Sciences : histoire orale

HAGENMULLER Paul, 2001-06-12

Sophie Jourdin — 2011-11-03T15:23:16Z

Paul Hagenmuller, born in Alsace in 1921, developed solid-state chemistry in France. He first initiated a research program at the University of Rennes (1956-60). In 1960 he set up a dynamic laboratory in Bordeaux. In 1964, Hagenmuller organized an international conference dedicated to the relations between structure and physical properties in oxides of the transition elements. The meeting gathered together chemists, crystallographers and solid-state physicists and prompted the establishment of an international community of solid-state chemists. In Bordeaux, Hagenmuller became the head of a research school working, at the interface between physics and chemistry, on the relation between atomic/electronic structure and physical properties, with a strong emphasis on industrial applications.

The Bordeaux research school has attracted scientists and students from all over the world (both developed and emerging countries) and many brilliant chemists of the next generation such as Jean Rouxel were trained in Bordeaux. Paul Hagenmuller retired in 1994. A jubilee celebration was organized at the Maison de la chimie in Paris in 1997. In 2001, his 80th birthday was celebrated in a special issue of the journal Solid State Chemistry.

HERVE ARRIBART (HA) : Pouvez vous retracer votre formation, vos débuts dans la carrière ?

PAUL HAGENMULLER (PH) : Depuis que je m'intéresse à la science je me suis préoccupé de la physique. Je me suis demandé pourquoi les matériaux avaient telle ou telle couleur, tel ou tel comportement électrique, magnétique, optique ... J'ai donc été porté vers la physique, plus tard vers la mécanique par extension, dès que j'ai entrepris mes études de science. Ces études ont eu lieu en 1940 à l'université de Strasbourg, repliée à Clermont Ferrand. Mon statut était celui d'un réfugié politique puisque j'avais quitté l'Alsace pour échapper au système politique allemand et parce que je me refusais d'être un jour mobilisé dans l'armée allemande. A Clermont, pour des raisons financières j'ai fait le choix de la chimie, séduit par la diversité des méthodes de préparation mais choqué parce que la chimie était alors très descriptive et n'était pas encore une science déductive, de réflexion.
Sur place, je suis entré en résistance, je faisais du sabotage. J'ai été arrêté en 1943 et envoyé en camp de concentration à Buchenwald. Là j'ai appris à me taire. J'ai travaillé sur les V2. J'ai appris le russe avec les prisonniers russes ; j'avais de bons contacts avec les communistes allemands. Puis j'ai été envoyé à Dora où c'était plus dur.
Après la guerre, André Chrétien m'a proposé un sujet de thèse sur la formation de nitrites complexes en solution aqueuse, puis une recherche sur la réduction de divers oxydes par des hydrures d'alcalino-terreux. J'ai accepté parce qu'il y avait un appareil mathématique. Puis au lendemain de ma thèse je me suis dit : il faut que je travaille sur des choses plus concrètes, les matériaux. J'ai voulu revenir à mes anciennes amours les matériaux. Je suis parti au Vietnam dans le cadre d'un accord avec la direction de l'enseignement supérieur et moi. Je partais pour deux ans 1954-56, au moment où la France se désengageait et voulait garder des relations culturelles. Au retour il était entendu que je pourrai choisir un poste de maître de conférences parmi ceux qui étaient disponibles en chimie. Ces deux ans de Vietnam ont été pour moi une période de décantation, de réflexion. Et quand je suis revenu j'ai voulu, d'une part, me préoccuper de physique ce qui suppose la détermination des structures atomiques - pour comprendre les propriétés physiques il faut savoir quelles sont les positions des atomes - et, d'autre part, il faut une certaine habileté à préparer des matériaux par des techniques nouvelles fort différentes.

HA : Quelles étaient alors les relations entre physique des solides et chimie des matériaux en France ?

PH : Aujourd'hui la physique s'est beaucoup rapprochée de la chimie parce que, de part et d'autre, on a compris que c'était indispensable pour faire des matériaux à propriétés spécifiques intéressantes sur le plan de la science fondamentale et intéressantes aussi sur le plan des applications. Au début des années 60, on en était à se chercher. Moi, j'avais fait un choix très clair : faire une chimie orientée vers la physique, plus tard vers la mécanique. Maintenant c'est devenu presque de routine, ne serait-ce que par ce que les chimistes pour bien connaître leurs matériaux sont obligés d'utiliser des méthodes de caractérisation physiques. La physique s'est imposée dans les perspectives de la recherche comme par les nécessités quotidiennes : savoir où sont les atomes et les électrons.
Donc au retour du Vietnam mon objectif était d'associer la physique et la chimie. J'ai eu la chance que dans mon poste à Rennes il y avait quantité d'excellents étudiants, mais en chimie personne ne voulait faire de la recherche sous prétexte qu'il n'y avait pas de moyens. J'ai décidé que j'allais lancer des thèses dans ce domaine à l'interface de la physique et de la chimie. On a d'abord tâtonné. On a travaillé sur le bore, sur les hydrures. Parmi les études réalisées à Rennes se trouvait la réduction d'oxydes par l'hydrure de lithium. On était intéressé par les hydrures de bore et d'aluminium qui comportaient des liaisons dites pont-hydrogène originales. Ceci m'a donc amené à réduire le V2O5 par l'hydrure de lithium et nous avons constaté qu'il y avait des phases intermédiaires qui devaient être les futurs bronzes de vanadium et de lithium, qu'on a appelées plus tard b et g. La phase a étant la solution solide de lithium dans V2O5. Alors j'ai pensé que ces matériaux étaient intéressants : s'il y a là un domaine d'existence, les propriétés physiques doivent varier à l'intérieur de ce domaine et si, par chance, ce domaine est suffisamment grand on peut faire ce qui est plus difficile dans les solutions solides limitées, de type oxydes non stœchiométriques. On s'est préoccupé de manière systématique des bronzes de vanadium qu'on a préparés par voie synthétique. Dans les années qui ont suivi - de 1960 à 70, j'étais alors à Bordeaux où un grand nombre de chercheurs de Rennes m'avaient suivi - on a préparé un grand nombre de phases de bronzes de vanadium par analogie avec les bronzes de tungstène qui avaient déjà été signalés. On a fait systématiquement des études magnétiques et électriques pour caractériser le mode de conductivité. Il est apparu que lorsqu'on insérait le lithium dans le réseau, on remplissait les états électroniques du vanadium, qui forment la bande de conduction. Les électrons devenaient donc de plus en plus délocalisés au fur et à mesure que leur nombre augmentait et on passait d'un état semi-conducteur à l'état métallique.

BERNADETTE BENSAUDE-VINCENT (BBV) : Quelles étaient vos relations avec le groupe de Robert Collongues ?

PH : Collongues avait été élève de Georges Chaudron, comme André Michel, Paul Lacombe, Jacques Bénard. J'avais d'excellentes relations avec Collongues. Nos domaines se recouvraient partiellement sur la non-stœchiométrie mais on avait des approches différentes. Lui enlevait des ions, nous on faisait de la chimie d'insertion. Collongues aimait bien se singulariser par rapport à moi mais dans la pratique nous avions la même politique sur des matériaux différents. Il y avait chez lui le même désir de systématique et de réflexion en profondeur. Collongues considérait que la bonne expérience était importante mais qu'elle devait illustrer une réflexion de fond. Il pensait que la science était avant tout la réflexion intellectuelle.
J'ai fait de la chimie sous pression à la manière d'un tailleur : choisir une structure cristallographique, écrire la formule d'une composition chimique, puis la stabiliser dans un degré d'oxydation élevé. Après avoir discuté la structure puis la formule, on préparait sous haute pression. C'était du design pour la conductivité électronique, les propriétés magnétiques, ou les propriétés magnéto-optiques et plus tard également pour la conductivité ionique.
Nous nous intéressions systématiquement à l'évolution de toute propriété physique originale en fonction de la composition et de la structure. Un nœud important dans cette évolution fut le colloque organisé à Bordeaux en 1964 sur les oxydes d'éléments de transition.

HA : Quelle fut la portée de ce colloque de 1964 ?

PH : Ce fut le moment où s'est constituée une communauté internationale de chimie du solide. Le colloque a rassemblé les chimistes qui nous étaient familiers, des cristallographes (Erwin-Felix Bertaut, Charles Guillaud), des physiciens (Jacques Friedel). Parmi les étrangers Mike Sienko, John Goodenough du Lincoln Laboratory au MIT qui est venu pour la première fois à Bordeaux ; des Allemands : Wilhelm Klemm, Rudolf Hoppe, Harold Schäfer ; des Hollandais, des Belges, etc. Il est apparu qu'une conjugaison des méthodes de mesure physique, des méthodes de détermination structurale et une certaine flexibilité pour les changements de composition, pouvaient permettre d'optimiser un certain nombre de propriétés physiques. D'abord le magnétisme, ensuite il y a eu la ferro-électricité - comment accroître la distortion ferro-électrique et par voie de conséquence la polarisation ; enfin, la conductivité ionique, d'abord dans des matériaux isolants au point de vue électronique et ensuite dans des matériaux dits cathodiques utilisables dans des batteries parce que conducteurs mixtes.
Je dois dire que ce qui fut déterminant pour l'avenir de la chimie du solide ce fut la venue de John Goodenough à ce congrès parce qu'il a popularisé parmi nous l'idée de l'importance de la liaison chimique. On a compris qu'on pouvait renforcer ou atténuer la liaison chimique en modifiant la composition, en particulier en jouant sur la liaison antagoniste. Par exemple si on compare le zirconate de baryum avec le titanate de baryum, la liaison baryum-oxygène est renforcée dans le zirconate par rapport au titanate. Inversement si on remplace dans le titanate de baryum, le baryum par le strontium comme la liaison strontium -oxygène est plus forte que la liaison baryum-oxygène, la liaison titane-oxygène est affaiblie, ce qui peut amener une variation très forte de la polarisation en fonction de la température, juste en dessous de la température de Curie. Et on peut avoir ainsi des matériaux aux propriétés intéressantes.

HA : Le rapprochement de la physique et de la chimie avec une orientation vers les applications constituerait-il donc l'identité de la chimie du solide à cette époque ?

PH : Oui nous avions un besoin civique de justifier les crédits que nous demandions par une application dans la vie économique. De plus, le travail avec des industriels fait naître des problèmes inattendus qui sont des challenges et qui sont nourrissants.
Une deuxième date importante dans l'institutionnalisation de la chimie du solide est 1978. Sur mon initiative la Société française de Chimie a créé en 1976 une division de chimie du solide, dont j'ai naturellement été le président. J'ai organisé la même année un premier colloque national de chimie du solide à Nantes. Sur ma proposition et sous ma présidence s'est tenu à Strasbourg en 1978 le premier congrès européen de chimie du solide, organisé par Jean-Claude Bernier (Strasbourg a été choisi pour une raison stratégique,). L'intervalle entre deux congrès consécutifs est maintenant de 3 ans ; le huitième congrès européen a lieu en juillet 2001 à Oslo.

HA : Quel était l'état des relations entre science et industrie en France à cette époque ?

PH : Il y avait une tradition de collaboration en métallurgie et en chimie : Chaudron et ses élèves, Lacombe, Bénard étaient très impliqués. Robert Collongues l'était aussi dans le domaine des monocristaux. Mais il y avait une forte hostilité syndicale au nom des grands principes : il ne faut pas mettre la science au service des grands intérêts privés. Les choses se sont atténuées à la veille de l'élection présidentielle de 1981. J'ai eu la visite de M. Kahane, longtemps doyen à Orsay, qui s'était rallié à la collaboration avec l'industrie privée. Cela a facilité cette évolution qui, de ma part, ne rencontrait aucune résistance car j'étais un scientifique et je n'avais pas à me poser des problèmes de déontologie qui me paraissaient un peu artificiels. Mais une partie de mon entourage était réticente à travailler avec l'industrie.

HA : Est-ce la crise pétrolière de 1973 qui a contribué à anoblir le rapprochement entre science et industrie ?

PH : Oui. Du fait de notre préoccupation entre propriétés physique et composition, nous avons été conduits à travailler sur des composés non-stœchiométriques d'intercalation et nous avons constaté après 1973 qu'il y avait possibilité d'intercalation ou désintercalation à basse température grâce à l'électrochimie comme on le faisait aux Etats Unis. Exxon et Bell étaient plus concernés que nous par la crise de l'énergie.
Les recherches sur la conductivité ionique ont été encouragées par la crise de l'énergie. Après la zircone déjà exploitée par Nernst, puis étudiée par la NASA et par Collongues ; il y avait eu AgI. Puis il y a eu l'alumine-b qui a suscité de nombreux travaux. CGE a dépensé beaucoup d'argent. L'alumine-b est un matériau très particulier. J'étais très sceptique. On a abaissé la température de fonctionnement, mais c'est encore trop haut pour un véhicule électrique. Et puis le soufre attaque la membrane. Finalement on a renoncé, pensant qu'avec des batteries au lithium on irait plus loin. Les derniers efforts de développement visaient plutôt le stockage d'énergie en période creuse. Les nasicons eux ne sont pas attaqués et ils présentent un avantage au plan fondamental car leur structure est plus simple. Ils ont de bonnes performances, qu'on pouvait maîtriser avec une juste proportion de sodium.

HA : Pouvez vous évoquer vos travaux sur la conduction ionique ?

PH : Avant 1973, on a publié un grand nombre de documents sur des conducteurs ioniques. On s'inspirait comme modèle de réflexion des bronzes de tungstène bien que la plupart des travaux publiés à l'époque fussent des études structurales et que les bronzes de tungstène soient métalliques. On avait également préparé une série de nouveaux bronzes de tungstène. Ce travail s'est étendu à des bronzes oxyfluorés, à des bronzes de vanadium et de molybdène contenant les deux cations vanadium et molybdène plus le sodium et le lithium. Puis au début des années 1970, on s'est attaqué aux premiers bronzes de manganèse NaxMnO2 et puis aux bronzes de cobalt KxCoO2.
Sur ces entrefaites il y a eu la grande crise pétrolière de 1973. Les pays occidentaux ont eu peur de manquer d'énergie et donc on s'est occupé de sources d'énergie non fossile et de stockage d'énergie. Un certain nombre de gens ont voulu faire des batteries. Exxon et la Bell Telephon, Whittingham et Murphy en particulier, ont travaillé sur ces matériaux non plus comme nous l'avions fait vers 500°C avec des phases en équilibre thermodynamique mais à basse température par intercalation ou désintercalation électrochimique.
Une spécialité à Bordeaux c'était les fluorures conducteurs. On remplaçait systématiquement l'oxygène par du fluor parce qu'il a la même taille et présente une liaison plus faible. On pouvait ainsi atténuer les interactions magnétiques. Comme pour la zircone, on dope les fluorures systématiquement. Watanabe avait déjà préparé les premières batteries au fluor.
Jean Rouxel s'était intéressé à l'époque où il était mon élève aux sulfures, aux sulfures à couche en particulier. Entre les couches de FeOCl et FeSCl par exemple, on pouvait intercaler beaucoup de choses, comme l'ammoniac ou les amines. Jean Rouxel a préparé NaxTiS2, un matériau qui avait été préparé par Rudorf à Fribourg, qui le considérait comme une curiosité. Mais Rouxel a très vite réalisé qu'il devait y avoir un domaine d'existence. Or il s'est avéré que Li xTiS2 avait un large domaine d'existence. Jean Rouxel a poussé dans cette voie et il a étudié un grand nombre de sulfures et sélénures à feuillets alors que nous nous intéressions plutôt aux oxydes. Il y avait une sorte d'accord empirique entre nous : Nantes les sulfures, Bordeaux, les oxydes. Nous avons étudié des matériaux sur le plan de la synthèse, dans des conditions d'équilibre thermodynamique plus que par intercalation désintercalation.
Il y a une grande variété de méthodes topologiques ou non de relative basse-température qui permettent d'obtenir des matériaux nouveaux. Mettre un mélange très fin de poudres sous hautes pression pour que se déclenche une réaction brutale qui prend fin lorsque l'un des deux constituants initiaux a disparu. Donc c'est un échauffement brutal suivi d'une trempe. Ce qui permet d'obtenir des borures ou des silicium stables seulement à haute température.
Beaucoup de ces matériaux sont métastables mais on peut les utiliser dans des dispositifs.
Jean Rouxel a apporté beaucoup dans le domaine des réactions d'intercalation-désintercalation. Les oxydes lorsqu'on les désintercale perdent des électrons cationiques. C'est une oxydation cationique. Lorsqu'on part de LixCoO2 vers CoO2 on perd des Li+, mais on perd également des électrons qui proviennent des niveaux d. Mais pour les séléniures, ce sont les niveaux anioniques qui sont les plus élevés. Et lorsqu'on oxyde, c'est l'anion qu'on oxyde. On passe de Se2- à Se- et de Se- à Se pour des raisons de stabilité de liaison. Et Jean Rouxel a montré qu'il y avait une évolution graduelle pour les éléments 3d à l'état de sulfure entre TiS2, qui a une structure à couches, et CuS2 qui a une structure avec un ion S de type pyrite. Il a fait une analyse précise dans les cas douteux où les niveaux cationiques et anioniques sont à peu près de même énergie. L'analyse très fine des distances inter-atomiques lui a montré si c'était le cation ou l'anion qui était oxydé. Il a également fait beaucoup de choses sur les bidimensionnels qui sont ici hors sujet.

HA : Qu'est-ce qui a manqué en France alors que les compétences étaient là pour donner l'impulsion sur les batteries au Lithium ?

PH : Il y a un très grand nombre de batteries réversibles au lithium pour des applications diverses depuis les montres jusqu'aux batteries de taille moyenne utilisées par les militaires pour observation spatiale avant bombardement. Mais le marché important, c'est le véhicule électrique, non polluant. Du moins en partie car on s'est résigné au véhicule hybride. Le véritable marché ce serait la voiture électrique -éventuellement hybride- ce qui suppose des batteries de grande taille. Probablement l'électrolyte sera un polymère PEO imprégné d'un sel de lithium avec un gros anion, type matériau Armand. La cathode sera probablement riche en cobalt ce sera un matériau voisin de LixCoO2, plutôt un oxyde qu'un sulfure parce que la tension est plus élevée. Mais pour l'anode ce n'est pas encore évident. Si on pouvait faire mieux que les composés d'intercalation du lithium on serait content. Mais actuellement il n'y a pas encore de solution. Il y a donc premièrement un problème de matériau qui freine cette évolution. Deuxièmement il y a un problème de prix. Ajoutez à cela qu'une batterie au lithium doit être scellée car le lithium est sensible à l'atmosphère et vous voyez que ce n'est pas évident. Une solution concurrente est la batterie hydrogène consistant à stocker l'hydrogène dans un alliage métallique et puis à libérer l'hydrogène. Ce modèle permet des puissances plus élevées que la batterie au lithium mais là aussi il y a un problème de vieillissement car après un certain nombre de cycles, l'alliage s'oxyde car l'oxyde est plus stable que l'hydrure. Ce problème n'est pas encore résolu avec un coût acceptable pour l'utilisateur. A cet égard, il y a une coupure entre le scientifique et l'utilisateur.

HA : Concernant les relations entre physique et chimie qu'est-ce qui a favorisé le rapprochement ?

PH : Les physiciens ont fait des efforts pour parler un langage plus proche de celui des chimistes. J'ai parlé déjà de John Goodenough. Nevil Mott aussi était un homme qui s'exprimait dans un langage compréhensible pour un chimiste. Par exemple, lorsqu'il a obtenu des transitions isolantes par changement de composition au sein d'un domaine d'existence, on comprenait ses préoccupations et il comprenait les nôtres bien qu'on raisonne sur des modèles un peu différents. On est ainsi arrivé à préparer dans des bronzes de tungstène oxyfluorés des matériaux qui sans changement de structure manifestaient une transition métal-isolant. Les physiciens ont fait des progrès. L'équipe de Friedel était très préoccupée de parler un langage qui nous était commun. Je pense à Denis Jérôme, Claude Berthier à Grenoble.

HA : Le travail de physiciens sur la caractérisation très fine vous a-t-il aidé ?

PH : Je me souviens de discussions à Orsay sur les hexaborures. Les physiciens voulaient des matériaux qu'on appelait thermo-ioniques - mais c'est un mot malheureux : on devrait plutôt dire thermo-électronique - c'est à dire ayant un faible potentiel d'ionisation et susceptibles de cracher un jet d'électrons relativement puissant sous tension faible. On en a fait une étude systématique et on a essayé de préparer des cristaux.

HA : Et quel était l'enjeu ?

PH : L'enjeu était d'avoir ponctuellement un faisceau d'électrons puissant, par exemple pour des soudures, des soudures localisées. Outre la collaboration avec les physiciens d'Orsay on a aussi collaboré avec ceux de Grenoble. Plus que ceux d'Orsay, les physiciens de Grenoble avaient un langage très compréhensible. Il y avait un grand homme à Grenoble, Louis Néel. Il avait publié son travail sur le ferrimagnétisme en s'appuyant sur des modèles structuraux très clairs. La répartition des cations entre les sites tétraédriques et les sites octaédriques de la structure spinelle. Donc on comprenait pourquoi on avait des interactions d'abord anti-ferromagnétiques - ce qui constitue la base du ferrimagnétisme - entre des sites tétraédriques A et des sites octaédriques B, et pourquoi l'aimantation résultante était accrue lorsque le réseau prévalent contenait des cations avec beaucoup d'électrons d célibataires. Tous ces travaux - encouragés par les recherches militaires - ont permis une collaboration très fructueuse avec Grenoble. Je pense à Bertaut en particulier. Nous avons été encouragés, par exemple, à faire des études basse-température par Pauthenay qui nous a dit : c'est aux basses- températures qu'on détecte les phénomènes peu énergétiques.
Alors c'est l'époque où nous avons manqué le prix Nobel - Je dis cela en plaisantant, bien sûr !-. Nous avons préparé les premiers oxydes purs de Cu3+ : par exemple SrLaCuO4. Nous avions une telle habitude des solutions solides qu'on pouvait imaginer de préparer une solution solide avec La2CuO4 contenant du Cu2+. Mais pour nous, les solutions solides, c'était du travail secondaire. On cherchait à préparer des oxydes purs. Si on avait été préoccupé des solutions solides on aurait pu trouver des oxydes contenant à la fois du cuivre Cu 2+ et 3++. Comme par routine on caractérisait tous nos matériaux jusqu'à la température de l'hélium liquide, on aurait trouvé la supraconductivité. On ne l'a pas fait parce qu'on voulait des phases pures et non pas des solutions solides.
Bernard Raveau l'a fait avant Alex Müller. Il avait un objectif : comprendre ce qui se passait au point de vue des corrélations. Passer d'un semi-conducteur à un métal. Müller était un très grand physicien. Il a été surpris aussi mais il a tout de suite expliqué. Raveau a fait ses solutions solides. C'est même moi qui ai transmis sa publication au M[aterials] R[esearch] B[ulletin] mais j'ai regretté à l'époque qu'il n'ait pas fait de mesure à l'hélium liquide.

HA : Après avoir évoqué vos collaborations en France, pourriez vous parler de vos liens avec l'étranger ? Vous avez été précurseur pour les relations scientifiques avec les pays en voie de développement comme la Chine, le Maroc et l'Inde. Quelles étaient vos motivations ? Comment voyez-vous la science des matériaux dans ces pays ?

PH : J'ai toujours été persuadé que la science devait être internationale. Cela me distingue de beaucoup de mes compatriotes. Je suis toujours étonné que l'on fasse des quêtes pour aider la recherche en France sur le SIDA. Toute la recherche sur le SIDA, toute recherche de pointe est internationale et ce n'est pas parce que la France dépensera un peu plus d'argent que nécessairement, il y aura des progrès significatifs. La science doit être internationale.
J'ai donc eu des liens d'abord avec les pays développés car dans ce type de relation on se fait connaître mais aussi on apprend. Je suis allé souvent aux Etats Unis, moins par enthousiasme culturel, que parce qu'on y rencontre des gens de qualité. J'ai rencontré Goodenough, Al Cotton... j'ai rencontré à Berkeley ou à Stanford des gens de grande qualité. J'ai eu des relations suivies pendant un temps avec la Grande Bretagne mais les Anglais ont un sentiment de quant à soi. J'espère qu'avec le temps la Grande Bretagne va évoluer vers une intégration dans l'Europe. Les Allemands sont très favorables à cette intégration. Dès 1961 j'avais pris l'initiative d'emmener tout mon laboratoire en Allemagne pour un voyage de 15 jours. On est allé à Stuttgart, Karlsruhe, Heidelberg, Darmstadt, Giessen, Göttingen etc.. On a été très bien reçu par Wilhelm Klemm avec qui j'ai toujours entretenu d'excellentes relations. Mais ses élèves étaient jaloux. Les Allemands se sont sentis bousculés parce qu'un peu jaloux de gens qui faisaient beaucoup de bruit. Ils avaient une bonne tradition de chimie préparative, en relation avec l'industrie. Les Allemands ont compris que pour faire des matériaux nouveaux il fallait des techniques nouvelles comme la haute pression. Mais leur but c'était la performance tandis que le nôtre c'était de stabiliser des structures électroniques peu usuelles, grâce à la synthèse. Les Allemands se sont senti un peu gênés. Les gens leur disaient : vous utilisez des équipements de haute pression mais ce que vous faites c'est de la botanique alors qu'il faudrait réfléchir. Le but d'un équipement est de faire des matériaux à façon pour répondre à des problèmes déterminés. Les collègues allemands avaient un autre point de vue et je regrette qu'il n'y ait pas eu davantage de liens.
En revanche, toujours parmi les pays développés, j'ai eu beaucoup de liens avec l'Europe de l'Est. Pour deux raisons. D'abord, il y avait des gens de qualité chez les Soviétiques, les Polonais et les Tchèques. De plus j'étais un peu agacé de cette Europe coupée en deux du fait de la guerre froide. Donc je trouvais raisonnable qu'il y ait une présence de la France là où c'était relativement facile, c'est à dire la science. C'était intéressant pour eux et pour nous car nous avons eu de ces pays des personnes remarquables. J'ai eu des relations systématiques avec des laboratoires à Prague, Cracovie, à Moscou, à Kiev, Novosibirsk, à Sofia. Avec la Roumanie, c'était impossible car Madame Ceaucescu interdisait aux scientifiques de discuter avec des étrangers.
Avec les pays en voie de développement, la situation change d'un pays à l'autre. J'ai eu des relations avec le Maroc parce que l'université de Bordeaux et l'université de Rabat avaient des liens traditionnels. Je suis allé y faire cours. Il y avait de très bons étudiants je les ai encouragés à faire une thèse. Le nombre a crû considérablement. 30 ou 35 Marocains ont fait des thèses avec moi. J'avais une politique de sélection impitoyable ; je prenais les meilleurs et je les surpayais. Je voulais qu'ils n'aient pas de souci matériel pendant leur thèse. J'ai eu des liens plus occasionnels avec la République du Congo et quelques Tunisiens mais ils préféraient Marseille.
Avec la Chine j'ai fait un choix politique. J'ai compris que la Chine était un potentiel économique et humain. La France devait être présente à un moment où la Chine était exclusivement tournée vers les Etats-Unis. Je suis allé souvent en Chine. J'ai fait venir des étudiants chinois en les choisissant bien sûr excellents. Mes espoirs ont été dépassés par le succès car ils ne sont pas retournés en Chine mais partis au Canada ou aux Etats-Unis comme professeurs ou dans l'industrie. Ils se sont bien débrouillés. Maintenant c'est différent ; une majorité d'étudiants chinois reviennent en Chine.
L'Inde est aussi un pays avec lequel j'ai eu des relations. C'est une société où le savoir est respecté, une science de caste malgré l'abolition officielle des castes. Thaïlande, Malaisie, Indonésie...j'ai privilégié les pays asiatiques par rapport aux pays africains car la culture asiatique favorise la réflexion métaphysique et par conséquent scientifique. Néanmoins j'ai eu aussi des collaborations avec le Brésil, le Chili et l'Argentine. Le but étant d'aider ces pays dans leur développement industriel. Je suis d'ailleurs membre de l'Académie des sciences brésilienne depuis 1988.
Vis à vis des étudiants du tiers monde, j'ai toujours considéré comme ma responsabilité de leur donner une thèse originale et non pas, comme on le fait souvent, de leur faire remplir des vides dans le laboratoire ou de servir de main d'œuvre. Les étudiants du tiers monde que l'on fait venir en Europe il faut bien les choisir et bien les former pour qu'ils deviennent des maîtres.

HA : Je serai curieux de connaître votre point de vue sur l'évolution de la chimie des matériaux et le rapprochement avec la biologie.

PH : Je ne me sens pas compétent dans l'interface chimie/biologie. Mais mon expérience à l'interface physique et chimie me rend plutôt sympathique cette perspective d'une ouverture de la chimie vers la biologie. Elle est défendue par Pierre Pottier, Guy Ourisson, Corriu.
Sur l'interface physique/chimie, cela s'est moins bien passé. Peut-être que je n'ai pas su convaincre. Quand on prêche, on se fait des adeptes mais aussi des ennemis. Cela est vrai au CNRS. Celui qui prêche secoue les caciques, les gens en place. Quelqu'un comme Fernand Gallais était fermement hostile à mon projet d'interface avec la physique. Par contre j'ai rencontré beaucoup de sympathies du côté de Pottier, de Jacques Livage.
Pour revenir aux oxydes supraconducteurs, il s'agit d'un cas intéressant de collaboration entre physiciens et chimistes. Très vite, j'ai compris que l'on avait plafonné et puis à un moment donné il était clair que Tc était d'autant plus élevé que la bande de conduction était plus étroite. Et plus la bande de conduction est étroite plus le matériau est instable et a tendance à se dismuter en donnant un mélange de deux phases. J'ai compris cela très vite mais beaucoup ne l'ont pas compris. Il y a donc eu un emballement. Il a rapproché les chimistes des physiciens. Il est dommage que personne n'ait proposé un modèle simple permettant aux chimistes d'innover de manière simple comme on avait innové dans le domaine de la conductivité ionique, du magnétisme, de la ferroélectricité, des magnéto-optiques ... ou même des composites thermo-structuraux. Il a manqué quelqu'un qui propose un modèle intuitif liant les propriétés à la liaison chimique. Goodenough aurait pu le faire mais il était trop vieux, trop pressé de publier des matériaux miracles. Les matériaux miracles sont difficiles à reproduire. Celui qui essaie il n'a pas le même four ... Ces matériaux sont métastables, ils ne sont jamais parfaitement purs. Ils n'ont jamais le même nombre de lacunes d'oxygène. Donc ce n'est jamais parfaitement répétitif. Cela exclut toute réplication sérieuse parce qu'un matériau n'est utilisable industriellement que s'il est relativement simple à préparer et à utiliser. Telle est la raison de l'échec de la diode Josephson sur laquelle IBM a dépensé beaucoup d'argent. A l'époque j'étais d'ailleurs conseiller d'IBM.

BBV : Est-ce qu'il y a eu des matériaux sortis de vote laboratoire qui ont été industrialisés ?

PH : Il y a d'abord eu les varistors. J'ai fait beaucoup avec la Thomson CSF dans ce domaine. Il y a eu LixCoO2 et puis il y a les céramiques composites de R. Naslain : fibres de carbone infiltrées par SiC qui permet de travailler à des hautes températures pour les matériaux de rentrée de la fusée ou du satellite dans l'atmosphère. Car lorsque l'engin revient dans l'atmosphère, il y a un risque d'oxydation. L'astuce consistait à infiltrer - non pas déposer en surface - SiC à partir d'une phase vapeur. Alors à l'air SiC s'oxyde en donnant SiO2 qui s'infiltre dans le matériau à base de carbone et permet de le prolonger.

BBV : Pourriez vous préciser quelles étaient vos relations avec l'industrie et comment elles ont évolué ?

PH : J'ai toujours eu des relations avec l'industrie. Quand j'étais à Rennes j'ai été contacté par Raymond Paul, un des responsables de la recherche à Rhône Poulenc et il m'a vivement encouragé à travailler avec Rhône Poulenc. J'ai eu plusieurs bourses de thèses payées par l'industrie - parfois il fallait publier des résultats plus tard. Rhône Poulenc a payé la thèse de Michel Pouchard sur les bronzes de vanadium au début des années 60. Ensuite il m'a paru tout naturel de travailler avec l'industrie. J'ai travaillé avec Saint-Gobain sur les verres, en particulier sur les verres conducteurs du lithium et du sodium avec Levasseur, sur les verres sulfurés à base de B2S3. Les verres sont un matériau merveilleux. Ils ont une composition qui est flexible. Vous tombez un peu à côté, cela n'a pas d'importance les propriétés ne sont guère modifiées. Vous n'avez pas le problème des matériaux cristallins où, par suite de la moindre erreur, de la moindre difficulté de préparation, une deuxième phase d'impuretés se forme à côté. Là il vous reste une phase. D'autant plus qu'on peut préparer les verres par trempe brutale donc énormément de matériaux sont vitreux alors qu'il y a 30 ou 40 ans c'était différent.
J'ai eu beaucoup de liens avec l'industrie locale : Aérospatiale et SNECMA, avec SNPA (société nationale des pétroles d'aquitaine : ancêtre d'Elf) sur comment purifier le gaz de Lacq...Ma porte était toujours ouverte, on élargissait le champ de nos recherches à la demande car l'industrie n'est pas un boulet.

BBV : Est-ce que ces liens étaient encouragés par le CNRS ?

PH : Le CNRS était informé bien sûr. Et puis quand on est devenu un laboratoire propre en 1966 Curien était très favorable aux relations avec l'industrie. On a un des contrats avec Saint-Gobain, avec Rhône Poulenc devenu Rhodia, avec Ugine Kuhlman devenu Péchiney. Nous avons même eu des liens avec General Electric aux USA pour les borures, avec BASF sur le di-oxyde de chrome pour les bandes d'enregistrement.

BBV : Quelles sont les méthodes et techniques utilisées dans votre laboratoire ? Et comment ont-elles évolué au cours de votre carrière ?

PH : Au début le B-A-BA c'était la diffraction X. Puis pour bien comprendre la structure on a eu un équipement pour des monocristaux. On a préparé des mono-cristaux pour déterminer les structures. Maintenant on a fait de gros progrès et on peut sur des spectres de poudres lorsque la poudre est de bonne qualité déterminer la structure par les méthodes Riedveld en faisant des hypothèses simples sur la structure la plus probable. La diffraction X a été fondamentale et a débouché ensuite sur la microscopie électronique en transmission qui permet de voir les défauts locaux. C'est merveilleux. La diffraction X était une méthode à grande distance. Par contre la microscopie électronique en transmission vous donne les défauts localisés et étendus. C'est une préoccupation que j'ai eu beaucoup à propos de non-stœchiométrie. Quand on passe d'une phase perovskite ABO3 à une phase brownmillérite A2B2O5, on perd de l'oxygène. Alors à haute température les lacunes d'oxygène sont désordonnées. A température plus basse, elles s'ordonnent en fonction du cation B. Quand c'est du fer ou du gallium, un cation isotrope, on a soit des tétraèdres parce qu'il y a pas de lacune, soit des octaèdres car les lacunes marchent par deux. Donc dans une structure brownmillérite on a une séquence octaèdre,-tétraèdre, octaèdre-tétraèdre, et dans la structure perovskite c'est octaèdre-octaèdre-octaèdre. Alors on peut trouver à condition de faire des recuits à température assez basse - quelques centaines de degrés - des phases intermédiaires avec 2 couches octaèdres, 1 couche tétraèdre, 3 couches octaèdres, 1 couche tétraèdre. Et bien sûr quand on chauffe le désordre s'installe à cause de l'entropie d'empilement. On a étudié de manière systématique comment on passe de défauts isolés aux défauts ordonnés, étendus. Et cela a des conséquences au point de vue de la conductivité de l'ion oxygène. Parce que maintenant on a de nouvelles préoccupations. On veut par exemple extraire l'oxygène de l'air par des membranes de perovskite lacunaire ou détruire les traces de CO en oxydant par l'eau. Dans ce cas, vous avez CO2 - qui est quand même moins toxique que CO, sauf sur le plan idéologique - et vous avez de l'hydrogène. On utilise des perovskites lacunaires qui doivent être conducteurs de l'oxygène - ce qui est normal - mais aussi conducteurs électroniques car le transfert se fait sous tension donc il faut que les ions O2- migrent à travers les lacunes de la structure. Il y a donc un aspect pratique pour les capteurs d'oxygène, la purification des gaz. Les Norvégiens utilisent ces méthodes massivement pour transformer le gaz de la Mer du Nord en un gaz exempt de CO. Norsk-Hydro dépense des sommes considérables pour cela. J'ai été invité pour parler avec les gens impliqués par ces recherches.
Donc pour résumer : nos efforts se sont situés à l'interface entre physique et chimie et se concentraient sur l'étude des relations entre composition, structure et propriétés avec la perspective d'applications industrielles.

Fin de l'enregistrement

haut de page

accueil du site

Pour citer l'entretien :

« Entretien avec Paul Hagenmuller », par Bernadette Bensaude-Vincent et Hervé Arribart, 12 juin 2001 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article124.
—

Entretien avec Paul Hagenmuller, par Bernadette Bensaude-Vincent et Hervé Arribart, 12 juin 2001

Lieu : Paris, France

Support : enregistrement sur cassette

Transcription : Bernadette Bensaude-Vincent et Hervé Arribart

Edition en ligne : Sophie Jourdin

BOILOT Jean-Pierre, 2000-12-12

Sophie Jourdin — 2011-10-28T12:00:58Z

Jean-Pierre Boilot worked on b-alumina in the 1970s and subsequently on ionic conductors within the framework of chimie douce.

BERNADETTE BENSAUDE-VINCENT (BBV) : Quel fut votre parcours individuel ?

JPB : Je suis entré au laboratoire Collongues en 1971, étant assistant à l'Ecole de céramique de Sèvres où j'enseignais la chimie. Mon sujet de thèse portait sur l'alumine-b plus exactement sur les gallates. On cherchait à améliorer la conduction ionique en remplaçant l'aluminium par du gallium. On connaissait, bien sûr, les travaux de Yao et Kummer et on savait déjà échanger les ions sodium par d'autres. Mais ceci n'a constitué qu'un chapitre de ma thèse qui devait en avoir 5 ou 6.
Après j'ai eu un rôle très particulier : travailler à l'interface de la physique et de la chimie. Cette expérience de collaboration de la physique et de la chimie du solide, c'était une innovation. Seul Yves Le Car avait commencé avant moi. Lui avait un financement industriel, avec CGE qui est devenu Alcatel. Cette collaboration est issue de discussions entre Robert Collongues et André Guinier qui était responsable d'un groupe de physique du solide à Orsay au bâtiment 510. Le Car a commencé à faire de la diffusion des rayons X, organisation des ions de conduction dans alumine-b. J'ai poursuivi dans cette voie. La collaboration s'est étendue. Je passais 50% de mon temps au labo Collongues et 50% en physique chez Guinier et chez Jérôme, un autre groupe de physique du solide qui faisait de la RMN. Une grande partie de ma thèse concernait des problèmes fondamentaux : comment les ions s'organisent, ordre désordre, stœchiométrie.

BBV : Quels étaient les modèles théoriques à l'époque ?

JPB : Peu de choses pour comprendre les mécanismes de conduction. C'est venu plus tard. Les physiciens durs ont attaqué le problème plus tard.
J'ai soutenu ma thèse d'Etat en 1975 devant un jury très impressionnant : Jacques Friedel, Jean Rouxel, Michel Fayard, qui est devenu directeur du secteur chimie au CNRS, Jeanine Théry et Robert Collongues. Je me souviens avoir été mauvais, je n'étais pas fier de moi.

BBV : Avez-vous poursuivi sur alumine-b ?

JPB : Oui de 1975 à 82 j'ai travaillé avec Gaston Colin, cristallographe et avec Philippe Colomban qui est arrivé au labo Collongues. Je l'avais eu comme étudiant à l'école de céramique. On a travaillé essentiellement sur deux aspects : alumine-b stœchiométrique et alumine-b''. Même type de base : compréhension, organisation des ions en utilisant les paramètres fondamentaux du solide : répulsion entre ions, transition au désordre etc.

BBV : Y avait-il alors une communauté française de chercheurs sur l'alumine-b ?

JPB : Oui, il y avait des séminaires organisés ici à Polytechnique par Bernard Sapoval->http://pmc.polytechnique.fr/bs/english.html] et Hervé Arribart. Les gens ici ont commencé à travailler sur l'alumine-b avec des porteurs de protons et ils utilisaient la RMN.
Donc si l'on fait le bilan de ces 10 ans, il y a deux caractéristiques propres à ce sujet

- C'étaient les premières recherches fondamentales menées parallèlement à la recherche industrielle car CGE en France, Ford, General Electric aux USA faisaient des recherches plus appliquées sur les accumulateurs sodium-soufre. C'était particulièrement motivant de voir qu'il y avait des possibilités d'application.
- Deuxième caractéristique : c'était la possibilité de travaux à l'interface physique-chimie. Ces deux aspects là se retrouvent plus tard dans les recherches sur les supra-conducteurs au cours des années 90.

BBV : Aviez-vous des contacts avec l'industrie ?

JPB : On avait des contacts avec CGE et on allait parfois à Marcoussis voir M. Dumas de CGE. Mais on faisait de la recherche fondamentale.
Des contacts avec l'industrie, il y en avait sans doute au labo Collongues. Mais je n'étais pas au courant. Par contre, au laboratoire Collongues, Didier Goureyet était plus proche des préoccupations industrielles, tout en étant en recherche fondamentale.

BBV : Avez-vous ressenti un certain pessimisme industriel sur l'alumine-b au cours de ces années ?

JPB : Non, il y eut une effervescence de 1970 à 76. Le pessimisme est venu après. Il y avait peut être des problèmes pour les gens qui ne travaillaient pas sur le sujet. C'est faux de dire qu'il y avait un pessimisme dans les années 70. Pour les années 80, c'est une autre histoire. Plus de problème d'énergie, d'autres problématiques sont arrivées : utiliser des systèmes. On savait que les batteries sodium-soufre ne seraient pas commerciales. Elles ne le seront peut-être jamais. Donc du point de vue industriel, c'était un tout petit peu moins motivant.

BBV : Avez-vous participé aux congrès internationaux des années 70-80 ?

JPB : Bien sûr je pourrai vous donner la liste. C'est un autre aspect important : il y avait une compétition internationale, essentiellement avec les Américains, avec les gens de General Electric - Roth - et les gens de Bell Telephon. J'ai commencé à participer en 1976 Schenectady ; 1979 Lake Geneva (USA), Gatlinburg (Tennessee) en 1981, Grenoble en 1983, Lake Tahoe en 1985 ; Garmisch en 1987. Outre cette série des Solid State Ionics il y avait Rome (1976) et Saint-Andrews en Ecosse, en 1978. A chaque fois on avait des papiers dans ces conférences.

BBV : Y-a-t-il eu une évolution ou réorientation de vos recherches sur cette période ?

JPB : On a pousuivi les mêmes pistes de recherche sur les deux alumines-b.
Philippe Colomban, chimiste, s'est consacré à l'élaboration des mono-cristaux d'alumine-b. Seuls deux groupes au niveau international savaient faire la synthèse des alumines-b : Colomban au laboratoire Collongues et Farrington chez General Electric. C'était un procédé à haute température avec quelques subtilités chimiques pour parvenir à faire l'alumine stoechiométrique. Mais il n'y eut pas de brevets sur les mono-cristaux. L'objectif était purement fondamental car les applications se faisaient sur un milieu polycristallin, céramique.
Parallèlement à partir de 1978, on a commencé à travailler sur d'autres conducteurs ioniques qui pouvaient remplacer l'alumine. Ils faisaient partie d'une série qu'on appelait nasicons : c'étaient des phosphates ou des phospho-silicates avec des ions sodium.
Le choix du sodium repose sur des arguments très simples : il faut un ion monovalent, de la bonne taille. S'il est trop gros il ne diffuse pas facilement ; s'il est trop petit (cas du proton ou du lithium) il vient se coller sur le réseau ; ou on a une interaction trop forte avec les anions (les chimistes disent trop polarisants). Les meilleurs ions sont Na+ et Ag+. Ensuite le choix dépend des applications. A cette époque là le problème était le stockage d'énergie, on visait des accumulateurs de haute puissance pour faire du stockage. Les critères de densité d'énergie massique portaient le choix sur les éléments légers, donc le sodium plutôt que l'argent.

BBV : Est-ce que la crise d'énergie a infléchi les recherches au labo Collongues ?

JPB : Peut-être mais à cette époque j'étais trop concentré sur ma thèse et je n'avais pas de vue d'ensemble. Pour revenir aux applications, les nasicons ont eu moins d'intérêt car ils sont moins stables, ils résistent moins bien au sodium liquide. Ils n'ont pas eu le succès de l'alumine-b mais des gens travaillent encore dessus. Il y a eu beaucoup de travail sur cette famille : diversité de compositions et de phases. Elle présente un intérêt pour la compréhension des paramètres fondamentaux du solide mais moins que l'alumine-b.

BBV : Rétrospectivement considérez vous que ce travail sur les nasicons a été positif ?

JPB : Oui on aurait peut-être pu arrêter un peu plus tôt. On a travaillé là dessus de 1978 à 1984 mais toujours en parallèle avec l'alumine-b. C'est un travail qui se faisait à Polytechnique où je suis venu en 1981. C'est un sujet qu'on a développé ici avec Colomban, toujours en liaison avec les physiciens du solide (Collin) d'Orsay dans le groupe de Robert Gomès qui avait pris la succession de Guinier.
Après on a pris un virage vers les sols-gels. La transition s'est faite par le biais des nasicons. On avait dans l'idée d'élaborer des phases amorphes pour conducteurs ioniques. Elles étaient dérivées du nasicon. On a préparé les premiers verres organo-minéraux en s'inspirant des conducteurs ioniques type nasicons. Notre modèle à nous était le conducteur ionique. Puis on a eu des résultats intéressants sur ces matériaux, sans rapport avec la conduction ionique. Ces hybrides organo-minéraux, à la frontière entre organique et minéral sont faits à température ambiante avec une chimie douce.

BBV : N'est-ce pas un paradoxe que de la chimie à haute température du labo Collongues sorti une chimie à température ambiante ?

JPB : Oui à la même époque Jacques Livage faisait des gels V205.

BBV : Qu'est-ce qui a motivé votre virage vers les verres ?

JPB : Du point de vue industriel, l'alumine-b c'était moins motivant et, du point de vue fondamental, on avait fait le tour. De plus, je démarrais un groupe ici à Polytechnique, c'était le moment de passer à un nouveau projet.

BBV : Est-ce que ce virage vers les verres organo-minéraux a changé votre place dans la recherche ?

JPB : Au niveau du CNRS, non, car on appartient toujours à la famille chimie du solide. Mais on a eu des contacts industriels nouveaux avec Saint-Gobain (Silor). Bien sûr pendant deux ans, on a eu un peu de ralentissement dans la production de publications. Mais le virage se fait bien.

BBV : Quelles sont les activités de votre laboratoire actuellement ?

JPB : Actuellement on est toujours sur la chimie douce. En plus des hybrides organo-minéraux, on travaille sur des objets nanométriques. On part de molécules et on essaie de construire des solides à partir de ces molécules. Ce sont essentiellement des matériaux pour l'optique : lasers ou stockage de l'information optique.

BBV : Quelles sont les techniques que vous utilisez ? Sont-elles totalement différentes de celles qu'on utilisait au laboratoire de Collongues ?

JPB : C'est de la chimie classique avec des béchers mais pas de haute température. C'est bien différent des labos d'alumine où on avait des fours à 2000°C. Le labo Collongues était surtout tourné vers l'élaboration de matériaux alors que maintenant on fait surtout de la caractérisation. Comme maintenant on dispose de nombreuses techniques, on peut faire des thèses sur la caractérisation avec peu de chimie.
Ce que m'a appris l'alumine-b c'est qu'il faut faire de la chimie. C'est le matériau qui est intéressant. C'est le message le plus important. Toutes les avancées qu'on a eues au laboratoire Collongues, c'est parce qu'on a su faire de la synthèse de matériaux avant et mieux que les autres. Notre premier travail est de faire de l'innovation en matériaux, mais on a beaucoup de collaboration en physique.
Notre troisième thème est la pile à combustible. Il est arrivé avec un ancien du laboratoire de Collongues : Philippe Barboux. Il travaillait sur les films minces de céramique et prépare maintenant des membranes conductrices ioniques pour les piles à combustibles. C'est donc un retour à la tradition d'origine.
Mais il y a un lien entre les verres, les particules nanométriques et les piles à combustibles. Ce sont toujours des procédés à basse-température. On travaille sur la diffusion de molécules comme autrefois on travaillait sur la diffusion des ions.

BBV : Combien de personnes travaillent dans votre groupe ?

JPG : Actuellement notre groupe de chimie du solide comprend 10 personnes et il est l'une des composantes de l'UMR-CNRS intitulée Laboratoire de Physique de la matière condensée qui comprend 50 personnes.

BBV : Quels sont vos liens avec l'étranger ?

JPB : Nous avons gardé des relations avec Bruce Dunn de UCLA (nous avons ici un chercheur permanent qui a fait son post-doc là bas). Nous avons également une collaboration avec un laboratoire allemand. Pas de programme européen, c'est trop de paperasses.

BBV : Comment voyez-vous la chimie du solide française sur la scène internationale ? Est-ce qu'elle n'a pas d'une certaine manière fait obstacle à l'essor d'une science des matériaux en France ?

JPB : C'était suite au démarrage de la physique du solide. Il y a avait a deux pôles de chimie du solide en France, celle de Hagenmuller à Bordeaux et celle de Collongues à Paris. L'une plus mandarinale que l'autre. Des gens comme Rouxel, je les mets dans la famille Hagenmuller. En fait, si on prend les labos actuels de chimie du solide, ce sont tous des descendants d'Hagenmuller ou des descendants de Collongues.
Les deux écoles sont tournées vers la science fondamentale plus que vers les applications. C'est totalement différent de l'approche science des matériaux aux USA. Elle n'existe pas en France. L'approche Materials Science est plus tournée vers les applications. En France, il y a eu beaucoup de recherche fondamentale. L'originalité française n'est pas dans la collaboration avec l'industrie mais dans l'approche physique, dans la collaboration entre chimistes et physiciens du solide. Je défends l'approche française. Si les gens avaient été très proches du milieu industriel, je ne crois pas qu'on aurait été aussi forts en chimie du solide.

BBV : Peut-on associer une coloration politique à cette discipline ?

JPB : Traditionnellement en France, les physiciens sont plutôt à gauche et les chimistes plutôt à droite. Quant à la couleur de ces deux écoles de chimie du solide, je dirais que Hagenenmuller était un gaulliste bon teint ; il serait plutôt proche de Pasqua aujourd'hui ; Collongues, lui, était plutôt centre droite, bon vivant.

Fin de l'enregistrement

haut de page

accueil du site

Pour citer l'entretien :

« Entretien avec Jean-Pierre Boilot », par Bernadette Bensaude-Vincent, 12 décembre 2000 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article121.

—

Entretien avec Jean-Pierre Boilot, par Bernadette Bensaude-Vincent, 12 décembre 2000

Lieu : Ecole polytechnique, Palaiseau, France

Support : non communiqué

Transcription : Bernadette Bensaude-Vincent

Edition en ligne : Sophie Jourdin

LIVAGE Jacques, 2001-01-04

Sophie Jourdin — 2011-10-28T11:49:52Z

Jacques Livage

Bernadette BENSAUDE-VINCENT (BBV) : Quel itinéraire vous a conduit de vos débuts dans un laboratoire de chimie des hautes températures à la « chimie douce » à température ambiante ? de la chimie du solide aux sol-gels ?

Jacques LIVAGE (JL) : D'abord mon origine n'est pas le laboratoire Collongues. Je l'ai rejoint dix ans après le début de ma thèse et à la suite d'un post-doc à Oxford. Après une formation de chimiste à l'Ecole de Chimie de Paris, j'ai préparé une thèse sur la zircone obtenue par précipitation. Ensuite je suis allé à Oxford pour étudier la résonance paramagnétique électronique - ce qui est un thème de physique. C'est en revenant que j'ai rejoint le laboratoire de Collongues.

BBV : En quelle année ?

JL : Je pense que c'était vers 1972 quand Collongues est venu s'installer à l'Ecole de chimie de Paris. J'étais sur place. Je ne connaissais pas a priori l'historique du laboratoire de Collongues. Alors pourquoi ai-je travaillé sur la chimie douce ? Il y a deux raisons.

- Cela tient à une raison personnelle. Au retour d'Oxford j'ai été journaliste scientifique à l'Usine nouvelle, à La recherche et journal Le Monde. Et c'est une idée que j'avais et que j'ai développée dans un article du Monde.
- La deuxième raison est opportuniste. Quand je suis arrivé chez Collongues, j'avais un contrat avec Kodak pour la réalisation de dorsales antistatiques qui étaient des oxydes de vanadium ayant des propriétés électriques. Il s'est avéré que pour pouvoir déposer cet oxyde, il était très commode de fabriquer des gels. C'est pourquoi je suis passé des hautes températures qui ordinairement servent à déposer des couches minces à la chimie douce. C'est donc une problématique industrielle qui a fait que je suis passé d'un thème haute-température à la chimie à température ambiante.

BBV : En arrivant chez Collongues, travailliez-vous sur contrat industriel ?

JL : Oui, il s'agissait d'un contrat Kodak qui portait sur des problèmes de mobilité électronique et la RPE que j'avais étudiée à Oxford est adaptée à l'étude des électrons. Donc j'avais une technique adaptée au problème.

BBV : Avez-vous pris des brevets ?

JL : Il y a eu des brevets pris. Malheureusement Kodak a pris les brevets sans nous en parler. Cela ne s'est pas très bien passé avec Kodak. Mais c'est un procédé qui a été commercialisé et qui est toujours utilisé actuellement. Toutes les pellicules que vous achetez sont faites de cette façon.

BBV : Avez vous continué dans ce domaine ?

JL : Oui on a continué, sans Kodak. Du moins sans Kodak France, en travaillant parfois avec Kodak Etats-Unis. C'est ce sujet là qui m'a fait découvrir les gels que personne n'étudiait à l'époque. Comme c'est un état de la matière qui est assez amusant, je me suis lancé dedans. Et il se trouve qu'en même temps que je travaillais sur les gels d'oxyde de vanadium, les verriers travaillaient sur les gels de silice. On s'est rencontré et puis on a travaillé ensemble.

A ce moment-là, du côté américain, il n'y avait pas grand monde. La Materials Society à Boston comptait une cinquantaine de personnes, pas plus. En France, on a créé un groupe sol-gel au CNRS qui regroupait une quinzaine de laboratoires français. C'était dans les années 80-90. C'était vraiment le démarrage : on rassemblait des laboratoires de chimie organique et de chimie minérale. Il y a eu des séminaires, des écoles d'été. Ensuite, avec des collègues allemands, on a fait un groupe européen et ensuite ça s'est diversifié.

Le domaine s'est constitué d'abord avec les verriers (les laboratoires de recherche sur le verre qui étudiaient les gels de silice). Ensuite se sont joints les céramistes dans le domaine de Materials Science qui ont beaucoup exploité cela pour fabriquer des céramiques. Et maintenant la voie la plus prometteuse ce sont les hybrides. Par la chimie, à température ambiante, on peut mélanger de l'organique et du minéral, en gros tous les intermédiaires entre du plastique, du plexiglass et de la silice, du verre. Et parmi ces matériaux hybrides, il y a un petit volet qui ne s'est pas encore développé : celui où au lieu de l'organique on a affaire à du biologique. Il s'agit d'insérer des enzymes, des cellules, des bactéries, des choses comme ça et de les faire travailler dans du verre.

BBV : Quelles peuvent être les applications de ces hybrides ?

JL : Pour ces matériaux hybrides ce sont les applications optiques qui sont actuellement en plein essor. On met des colorants organiques dans du verre. En fait, il y a des applications réelles, commerciales : typiquement des films minces sur du verre . Il y a pas mal d'industries qui ont lancé des départements sols-gels, par exemple le CEA.

L'oxyde de vanadium a des applications multiples :

- semi-conducteur on l'utilise en film mince pour les dorsales antistatiques. C'est facile on l'étale au pinceau. Le premier brevet pour l'application en couche mince est un brevet allemand (à Iena) de 1939. Mais le procédé ne fut commercialisé qu'en 1959
- c'est l'un des rares matériaux minéraux qui présente un comportement cristal liquide
- on l'utilise comme matériau d'électrode dans les batteries au lithium. Il a un fort potentiel, 3 volts et se laisse mettre en couche mince. Il est donc envisagé pour les portables ;
- au Japon et aux USA on l'utilise aussi comme solvant pour des liants.
- Une application plus classique mais pas encore commerciale concerne l'affichage électrochrome comme l'oxyde de tungstène.

BBV : Vous avez toujours travaillé en étroite collaboration avec l'industrie. Quelles sont les modalités de votre collaboration ?

JL : C'est essentiellement du financement de thèses et de post-doc. Actuellement les brevets sont pris par des industriels avec les noms des auteurs. Les brevets, les licences d'exploitation ce n'est pas nous. Nous n'en retirons aucun bénéfice financier. Nous les bénéfices que l'on a c'est

- que l'industrie finance des post-docs,
- qu'ils embauchent pas mal de gens qui sortent du labo. C'est quand même important pour un laboratoire de recherche et de formation.

BBV : Dans quelle mesure ces liens avec l'industrie ont-ils orienté le cours de vos recherches ?

JL : Au début, on l'a vu, c'est un intérêt industriel qui m'a aiguillé vers les gels. Mais après je ne pense pas qu'il y ait eu de virages. Les enjeux des gels sont très importants pour l'industrie et on était un des rares labos à faire de la recherche fondamentale en ce domaine. En fait c'est toute la chimie des solutions aqueuses. Toute l'industrie des céramiques, des catalyseurs des pigments utilisent déjà ces procédés mais n'en ont pas la science. On a plus apporté un savoir faire, une compréhension, une matière grise que des solutions à des problèmes directs.

BBV : Quelles sont les opérations que vous faites avec ces gels ? Quel genre de techniques utilisez-vous ?

JL : La caractérisation des gels n'est pas facile. Ce sont des systèmes qui ne sont pas cristallins.. La technique la plus importante c'est la RMN et puis l'absorption X les XAS.

La première étape c'est l'élaboration. Faire un gel c'est comme une mayonnaise, il faut le coup de main et puis il faut comprendre le pourquoi et le comment. On a un gel dans un flacon. C'est joli mais pour savoir ce qu'il y a dedans la deuxième étape c'est la caractérisation et puis après il faut voir s'il n'a pas de propriétés intéressantes. Les propriétés essentielles qu'on étudie au laboratoire sont des propriétés optiques et électriques.

BBV : Allez-vous jusqu'à l'étape de la fabrication de prototypes ?

JL : Prototype de laboratoire, non sophistiqué, oui. Mais pas les prototypes industriels. On n'est pas du tout équipé pour ça. De plus, je ne connais pas les besoins économiques. On a déposé une quinzaine de brevets sur 5 années. Mais toujours pris par les industriels. La seule fois où j'ai pris un brevet d'Etat par l'ANVAR cela a bloqué une collaboration avec Saint-Gobain.

C'est peut-être une politique personnelle mais j'ai choisi de faire de la recherche fondamentale et l'institution nous juge sur cette science.

Notre point fort c'est plutôt la matière grise. C'est de la chimie fondamentale. La chimie la plus répandue dans le monde est la chimie des solutions aqueuses. Du point de vue industriel c'est évidemment la moins chère, la plus simple. Et curieusement les connaissances théoriques là dessus sont beaucoup moins développées qu'en chimie organique.

BBV : Quels sont les problèmes théoriques soulevés par les gels ?

JL : Le problème essentiel est de savoir quelles sont les espèces que l'on a dans la solution. En général on n'a pas une espèce mais un mélange, très fugace donc des dynamiques, des cinétiques très rapides. Il n'est donc pas évident de savoir qui est important dans un bécher. Une fois que l'on a compris les mécanismes on peut maîtriser le système et fabriquer ce que l'on veut.

BBV : Comment nommer cette chimie ?

JL : "Chimie des hautes températures", c'était exclu vu qu'on travaille à température ambiante. "Chimie du solide" ne convenait plus, vu que les gels c'est de la matière molle.Chimie de la matière condensée c'était le pendant de la physique de la matière condensée pratqiuée au laboratoire de De Gennes.

BBV : Dans quelles circonstances avez vous lancé l'expression « chimie douce » ?

JL : Chimie douce est une expression que j'ai avancée du temps où j'étais journaliste scientifique. C'est une époque où j'écrivais un article dans Le Monde tous les mois. C'est le titre d'un article publié le 26 octobre 1977 dans Le Monde. C'était au moment du choc pétrolier, des problèmes d'énergie. L'idée était la suivante : ce que l'homme ave l'industrie fabrique à des hautes températures, la matière vivante le fabrique à température ambiante. Il y avait donc peut-être quelque chose à apprendre de ce côté là.

BBV : C'était donc une inspiration biomimétique ?

JL : Tout à fait. Absolument.

BBV : Quel est le devenir de cette expression chimie douce ?

JL : L'expression a été reprise facilement, indépendamment de moi. Dans les milieux anglo-saxons on parle de « chimie douce » en français et non de soft chemistry. De toute façon aux USA tous ces secteurs de chimie du solide, de la matière condensée etc sont couverts par l'ombrelle Materials Science.

Sol-gel n'est que l'un des aspects de la chimie douce. Elle comprend aussi la biominéralisation, les composés d'intercalation. Rouxel avait coutume de distinguer deux classes de composés en chimie du solide :

- à précurseur moléculaire (par précipitation)
- à précurseur liquide comme les argiles ce sont les composés d'intercalation.

La chimie douce suppose toujours une phase liquide : d'où la mobilité des ions.

BBV : Dans quelle communauté êtes-vous inséré. Dans quel journaux publiez-vous ?

JL : Dans des revues de physique, le Journal of Solid State Chemistry ; Chemistry of Materials. Il existe bien un Journal of Sol-Gel Science and Technology mais il n'a pas acquis le prestige des journaux de chimie des matériaux.

Tous les deux ans, nous avons un congrès de la communauté sol-gel. Le premier a eu lieu en 1981 en Italie. 300 ou 400 personnes se réunissent. Si l'on compte que chaque laboratoire envoie environ deux personnes on peut évaluer la communauté à 3 ou 4000 chercheurs.
Les pays forts en ce domaine sont les USA (verriers et céramistes), la France et le Japon. Puis l'Allemagne, la grande Bretagne et l'Italie.

BBV : Avez vous des contacts avec la chimie des colloïdes ?

JL : Peu de contacts. La chimie des colloïdes est plus orientée vers la recherche fondamentale sur les problèmes de surface. Sol-gel, c'est très industriel. Notre chance c'est d'intéresser l'industrie tout en faisant des recherches pas trop appliquées.

BBV : Quels sont les effectifs globaux de votre labo ?

JL : Le laboratoire de chimie de la matière condensée appartient à une UMR CNRS intitulée matériaux inorganiques. Elle comprend 100 personnes en trois unités rassemblées sur la montagne Sainte-Geneviève. L'équipe de Chimie de Paris avec Noël Boffier qui fait des batteries ; l'équipe de l'ESPCI avec Philippe Bosch, céramiste ; et notre groupe sol-gel ou chimie de la matière condensée. L'intérêt de cette union c'est 1) qu'on développe une politique commune et ainsi on évite la concurrence ; 2) on a une bonne implantation pour le recrutement des étudiants. J'enseigne à l'ENS et Clément Sanchez à l'X ce qui permet de recruter. Sol-gel n'est pas encore un sujet académique et les jeunes ont tendance à aller vers ce qu'ils ont appris à l'école. Nénamoins les sols-gels attirent les jeunes. Ce qui dans ce temps de pénurie est un gros avantage. On a 15 thésards en moyenne. C'est un labo qui est jeune la moyenne d'âge est inférieure à 40 ans.

BBV : Quelle est la part de l'industrie dans le financement de votre laboratoire ?

JL : 1/3 vient de l'Etat et 2/3 de l'industrie mais ce ratio n'inclut pas les salaires de chercheurs qui viennent de l'Etat. On a aussi beaucoup de contrats européens. La gestion est assurée au niveau central par Jussieu.

BBV : Vous sentez vous appartenir à une communauté de chimistes ou de materials science ?

JL : Non on est clairement chimiste. En France il n'y a pas de Materials Science

BBV : Comment expliquez vous l'échec des tentatives françaises pour constituer quelque chose comme un secteur science des matériaux ?

JL : Il y a eu des efforts faits par le CNRS quand il était question de faire des commissions regroupant physiciens et chimistes. J'étais à l'époque chargé de mission pour chimie et j'ai une des réunions avec mes homologues pour la physique. Mais ça n'a jamais marché. Le public n'a pas suivi. Je pense qu'il y a eu de très bonnes collaborations entre la physique et la chimie. Le CNRS a fait plusieurs tentatives.C'est l'université qui a fait blocage. Blocage dans les structures plus que dans les mentalités. Dans les structures universitaires on est dans des départements différents. La carrière d'un physicien ne dépend pas de celle d'un chimiste.

Ce qui ne veut pas dire qu'ils ne travaillent pas ensemble. Il y a beaucoup de collaborations Par exemple ce que j'ai fait sur les cristaux liquides c'est avec des physiciens d'Orsay. Pas mal de choses en électrochimie, sur les batteries aussi avec des labos de physique mais on vit dans des commissions séparées, au CNRS et à l'Université. Donc ce sont des milieux qui ne sont pas amenés à vivre ensemble. On ne trouve rien comme ces unités aux Etats Unis qui regroupent physique, chimie et mécanique.

Par contre ce qu'on a fait avec les physiciens ce sont des filières d'enseignement, des filières matériaux. Curieusement elles ne se trouvent pas tellement dans les grandes écoles. Mais dans les universités à Montpellier, Bordeaux, Nantes. La demande est profilée en liaison avec la demande industrielle. On recrute à Bac+2 et on les porte à Bac+5. Il y a des industriels parmi les enseignants et des stages en entreprise. Il y a aussi quelques instituts matériaux : à Nantes, Strasbourg, où il y a à la fois des physiciens et des chimistes.

BBV : Quel est le contenu de l'enseignement de matériaux ?

JL : Il est orienté sur trois dominantes. Les polymères, les métaux et les céramiques.

Mais surtout il existait une forte communauté chimie du solide qui occupait déjà la place. Historiquement elle est née avec Hagenmuller et Collongues. C'est là que la chimie minérale est devenue chimie du solide. Les deux familles ennemies (les écoles de Chaudron et de Chrétien) se sont réconciliées par l'intermédiaire de leurs élèves : Hagenmuller et Collongues. Deux personnes fondamentales pour le développement scientifique et pour le fait qu'elles se soient entendues ensemble. Ils ne se sont pas tirés dans les pattes. Ils se sont épaulés. Ils ont été capables de faire une politique scientifique commune. Ce sont deux personnalités très différentes, deux styles différents avec des thèmes de recherche différents. Je crois que c'est là que la communauté s'est soudée avec ces deux rameaux qui se sont bien entendu. et les élèves des uns et des autres ont continué.

Fin de l'enregistrement

—

haut de page

accueil du site

Pour citer l'entretien :

« Entretien avec Jacques Livage », par Bernadette Bensaude-Vincent, 12 décembre 2000 Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article122.

—

Entretien avec Jacques Livage, par Bernadette Bensaude-Vincent, 4 janvier 2001

Lieu : Laboratoire de chimie de la matière condensée, Tour 54 (5e étage), Université de Jussieu, Paris, France

Support : non communiqué

Transcription : Bernadette Bensaude-Vincent

Edition en ligne : Sophie Jourdin

EAGAR Thomas, 2002-05-06

Sophie Jourdin — 2011-09-19T08:55:20Z

Thomas Eagar

Lord Professor of Materials Engineering and Materials Systems, MIT.

Pour citer l'entretien :

« Entretien avec Thomas Eagar », par George Smith (Acting Director of the Dibner Institute) et Arne Hessenbruch, 6 mai 2002, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article83.

GEORGE SMITH (GS) : I am NOT, as such involved, but I'm starting to get interested, and this book [referring to Robert Cahn's Coming of Materials Science] has drawn me in very heavily. I've tended to be very skeptical, because of course the people, all the people I work with are really metallurgists, not Materials Scientists. [Richie Glue] knows less quantum mechanics than I do, and that's not saying very much. And you ! I would think of you very much as a metallurgist, trained at MIT. And you became chair of Materials Science ! What's your picture of the change from metallurgy to Materials Science ?

THOMAS EAGAR (TE) : Well, I have baggage, in that as a sophomore I took Cyril Smith's course, and the book The Search For Structure, and all that stuff, right ? If we go back to the beginnings of Materials Science, and... ... this is sort of a Cyril Smith view, it was at the Sorby Centennial Symposium, you may have come across that back in the 1960's. Cyril edited it. When I became a metallurgist, in the early 70's, they talked about metallurgy being structure-properties relationships. And then, Mert Flemings and a few other people kind of felt left out by that, so they started calling it processing-structure-properties, so by the time I was a Senior and a graduate student, it was processing-structure-properties, in about 1970, or actually 1972. Well, in '71 and '72 I served on an undergraduate committee to revise the undergraduate curriculum, I was the token undergraduate. Then they had a committee to revise the graduate curriculum, then I was the token graduate student the next year. That was the Morris Cohen committee. That committee was at the same time that Morris Cohen was coming out with the National Academy of Science report. You know that ?

ARNE HESSENBRUCH (AH) : COSMAT.

TE : Got the whole thing ?... I actually... [Marge Meyer] left me somewhere, the whole thing, I mean there was only one copy, you know this was before they made lots of copies of things. Anyway, I also, in 1973, while he was writing [Cosmat], was TA'ing for Morris Cohen, basically lecturing his course. And then in 1989, when they came out with Fleming's report, the NAS follow-up report, where they had the tetrahedron, processing, structure, properties, and performance, that's kind of where it was, but really, that... and I say "1880," I kind of subscribed to the Cyril Smith view that it was the Sorby's ability to do metallography and look at an internal structure. They always knew, if you go back a thousand years before, people would see crystalline structure on fractures or things like that, and Cyril goes through all that in The Search For Structure, but they really never could begin to explain it until Sorby basically gave them the tool of metallography. Then in the 1920's, x-rays came along. So they had several... they started developing new tools. In fact in 1985, I wrote an article for the Journal of Metals, where I kind of said that Materials Science had matured because it now had a theory, quantum mechanics, to explain what they could measure in characterization, and they could now produce (by things like molecular beam method, things like that) on an atom by atom scale. So Material Scientists have this whole range of structural scales, from atoms on up. Sorby started out by showing them that you can measure structure in the microscope and correlate that with properties. But they didn't have a theory to tie the two together. And they really didn't have very good first principles fabrication schemes to build up if they did have a theory. So anyway, the theory came along, the characterization tools came along from 1880 through, they're still coming along today, but I mean it was first Sorby, and then it was x-rays, and then you have the transmission electron microscope in 1950, and things like that, and they could start to measure things on an atomic scale, and all kinds of other scales in between. But measuring something doesn't allow you to do much with it unless you have a theory to go with it. Well quantum mechanics gave the theory, except the problem was quantum mechanics didn't have the power until the 1980's when the computer allowed them to do something more than a hydrogen molecule. In quantum mechanics, they had the fundamental equations, but they just couldn't solve the complexity of the equations. Now, we actually can design materials on a computer that have never been built before, and predict what the properties are. And now we actually, in the 1970's, 80's, and 90's have developed techniques so that with something complex you can actually build things up atom by atom if you have to. That's not necessarily what you want to do, but you can. So I said, this is the 1985 paper I wrote, I said, "That's what was placing Materials Science in a whole new realm to move forward." Because they had this triad of theory, characterization theory, and fabrication and processing techniques to build what they predicted. And I compared that to Biotechnology in 1985, and said, "It would be wonderful... Well, recombinant DNA gave you two of those : the characterization technique and the building technique." You got both, but you didn't have the theory. And at that time everybody said or people were saying Materials, Biotech, and Information Technology were the waves of the future. This is in 1985, now this is 17 years ago. I said "Well look. Information Technology is growing," (I didn't say too much about that but you could see the growth in 1985) "and Materials" I said, "really was poised, to be able to do some great things." And then, Biotech... and I was in favor of doing the human genome and stuff, although I'm not sure that was even out yet, but I was in favor of that, but I said "Until they develop a theory, they're not gonna be able… just because they have the characterization tools and the assembly tools, unless they know what they want to build, they're still gonna be doing things empirically." And that's a much slower process. And I think that's still true to a certain extent. Now they've got the human genome, and they're starting to develop others, then someone's gonna come along with the theory at some point, and figure out how these genes actually create these proteins and everything else. But they're not there yet, so there's still a lot of empiricism....But my thesis was that once you get past empiricism you have to have a theory to tie everything together. In Materials you have to have characterization, theory and then experimental assembly. Anyway, that was kind of my view of Materials Science. I wrote another paper about two or three years ago, where I said "Ok, lets look back and see if we can see what happened." Everybody has seen the growth of the Information Technology, and everybody still talks about biotechnology and growth. This was three or four years ago. The biotechnology boom hadn't quite taken off, although to a certain extent it has much promise still. But the thing about Materials is I called it, the paper was called "The Quiet Revolution in Materials Science and Engineering," and it's the "quiet revolution" because it has been a cost avoidance rather than a new business. Everybody in 1985 was predicting that Materials Science, Information Technology, and Biotechnology would create new businesses. And in Information Technology, and communications, and biotechnology, they have ! But what are the new businesses in Materials ? The employment is going down in the manufacturing industries. Steel companies have become four or five times more productive in the last 20-25 years. But the growth and the consumption of steel isn't going up, because there's only so much you can "eat." So the problem is there actually has been a revolution in Materials Science and Engineering, because we have this triad of theory, experiment, and stuff. We actually have had tremendous gains in productivity. I mean, the steel industry had doubled the productivity of the rest of American Manufacturing in the 1980's. For a whole decade ! That might be necessity.

GS : By how much did it grow ?

TE : It was like 6-8% a year versus three or four in manufacturing. And one percent, or zero, in the economy as a whole. I mean, you went from something like 6 man hours a ton to 1 man hour a ton to produce steel in a ten year period ! Well that was partly because they cut all the fat, they probably got half of that by cutting the fat, but the rest of it actually came from technology improvements and rethinking the way they did things. Part of that is that "necessity is the mother of invention." They were going to go out of business if they didn't ! Now it turns out they are eventually going to go out of business because we don't have the raw materials advantage that we had in the 1800's. We don't have the labor cost advantage we used to have. So frankly, the heavy metals producing industries, they're not glamorous industries that society wants to keep. They think of them as "dirty" industries they'd rather do offshore. Export your pollution, right ? That's not to say that Materials Science, and you can take steel or you can take silicon, you can take either one, the productivity gains were tremendous. But nobody notices that because people don't purchase a material, you buy a computer. You're buying functionality, you're not buying a material. That was my thesis in 1998 or whenever I wrote that article on "The Quiet Revolution." Which was sort of sequel to my 1985 article, on the idea that you have to have this triad of theory, fabrication, and characterization.

GS : A quick aside first and then I have two lines of questioning.

TE : Well, by the way, I've got a student who has applied for a patent on a, he calls it a "linear metal foam," but basically it's just holes in a substrate. The application is to blow air through this thing for a semiconductor cooling heat sink. Well, what you need now, because this thing is less than a cubic inch to cool the semiconductor, whereas the actual pins inside your computer now are maybe 50 cubic inches. You have a tremendous space advantage, but you need an air compressor ! You only need 30 psi, but we'd like to...

GS : No, we can do that...

TE : We want something...

GS : No, no, but that we can do.

TE : I know.

GS : We are doing things like that.

TE : In fact, I told Chris, he's trying to get venture capital and all this other stuff and start a business, he was actually one of the finalists in the 50K competition, but he finally pulled out, because it looked like he was close to getting real venture capital money. Intel's interested... it's the limiting thing on servers right now !

GS : Ok, let me pursue. These are two totally separate lines. You talk about theory, and I understand the point. Except I'm worried. You're right, but the ability to do computations in quantum mechanics beyond the hydrogen atom took off in the 1980's. But those are still not real computations. They're like the CMD computations. You make extraordinary simplifying assumptions, in order to get any kind of numbers out, and I look at them and I think of them more as engineering tools than physics.

TE : I'm not sure I disagree. I think I will agree with that, however, in some cases they've done very well, and the example I used to use when I was department head was Gerd Ceder who's now a full professor over there. He was an untenured associate when I became department head, and his claim to fame was lithium electrolytes for batteries. People used lithium cobalt and lithium manganese. I don't know what the anion was... maybe it was just lithium cobalt oxide and lithium manganese oxide. Basically, what they did is... Gerd basically developed this model, he was one of the first guys who could do ceramic systems as opposed to metals, where the bonding is non-directional, and everything. Anyway, and people couldn't do the ceramics because the bonding was longer range order, and as you say, they have to really do some very simplifying assumptions, and they can only do their calculations at absolute zero. We can't handle the entropy and so forth. I don't disagree with what you're saying, but what he did in that case is he was able to take out the cobalt and the manganese out of that oxygen lattice, which you can only do on the computer. He showed that the highest voltage you would get is if you completely removed the cobalt and the manganese part of the anion, and you just had lithium and oxygen in that crystal structure. Well that's an impossible thing to make physically, but from that, they basically came up with an alloy, lithium aluminium manganese or something, oxide... I don't remember exactly what it was right now, but the compound, which basically they predicted in the computer, what they need in terms of the interatomic spacing. That was really all it was. You can change the lattice spacing in the computer a lot easier than you can in the lab. Then [Nyet Ming Chang] went off as part of this team and made it. And Don Sadaway and Anne Mayes measured its properties and it was the best of the lithium electrolytes, solid electrolytes, for batteries. That was kind of one of the things that helped Gerd's whole tenure case and promotion case. He was really, so far as I could tell, the first person to predict the properties of a material in the computer before it had ever been made. Everybody else was always, "Ok we made the material, now lets go do our fudge factors and show..."

GS : Yeah, we well realize that what you're doing there is self-fulfilling prophecies.

TE : Yes.

AH : When was this ?

TE : This was about 1995 or so they did this. But it was the first, and you know, I took his tenure case forward, and the letters came through, and he was the first person to ever have, I mean that's what everybody was saying. And now the physicists looked down on him, because the physicists wanted to, they were interested in developing the fanciest new tools. Gerd was someone who basically said "Well what are the tools that are out there ?" He would pull whatever tools off the shelf, from the physicists, that made sense to solve this problem. He was an engineer ! He likes to think of himself as a scientist, but if you really get down to it, he's really an engineer, an engineer uses tools available, and engineer's not out there creating tools. That's the scientist's job. So, the physicists, I had to be very careful when I went out for letters, that I didn't try to get too many physicists who were going to look down and say "He doesn't have a computer program, a code, that he is the father of. Basically, I convinced Bob Brown, who was the engineering school dean, was that Gerd was a star because he could use any tool that was out there. He was intelligent enough to take the tools developed by others and apply them. Yes, they all have approximations, but he was able to put the right couple together, to come up with a prediction, which was a very useful prediction. And by the way, predicted the voltages out of 4.5 volts, predicted them within like a tenth or two-tenths of a volt. That's not too hard to believe that you can do that. All you're doing is changing the lattice spacing between the oxygen atoms. The other thing he did was that everybody really thought it was the lithium that was carrying the charge, and it turns out it was the oxygen vacancies. He kind of, not only did he, you know, predict it in the computer, but he actually, the computer told him what was counterintuitive to everyone else's assumption. Everybody figure, lithium's a wide ion, and it moves through there quickly, but no, it turns out it was the oxygen vacancies that were moving in the opposite direction. That came out, all those predictions, came out of the computer before anyone ever made the material. They made the material in almost the first time they made it, and they confirmed the theory. I'm not sure I can give you another example in the last seven years, that's maybe because I'm not department head anymore, and I'm not following all that, but it is going to come.

GS : Ok, fair enough. You realize the same thing is going on in quantum chemistry and physics. Long thought on the simplifying assumptions...a real interest in it. In the last few years, as computers have become more powerful, and being used to synthesize molecules. Now, let me ask the follow-on question, do you see any sign so far, of feedback from Materials Science Research into physics as such ?

TE : No. Do you think that physicists would even think of talking to a Materials Scientist. I mean, this is the hierarchy of snobbery !

GS : Well, I understand all of that, but remember there was a Scientific American article, roughly a year ago, by a physicist out in the Midwest, I think it was Wisconsin, talking about the design of materials along the lines you're proposing. I found the article to be a sales pitch.

TE : Well, they're worse than that. I don't remember that one, because I probably just looked at it and threw it away, you know, read a few of the figure captions and decided "This guy is a physicist and doesn't know what he's talking about." I remember the one that was in Technology Review, about 4 or 5 years ago, maybe 5 or 6 years ago. They had a little linear induction motor made out of atoms. I forget how, I said this... oh, they called it a planetary gear. It wasn't an induction motor, it was a planetary gear. And they actually had four or five atom molecules that were the gears. They tried to draw these things as if each little atom... this came out of Lawrence Livermore, right ? Some computational... basically it was a mathematician, who would work with some materials scientists, and it was all a big sales pitch. And I said "This is not a planetary gear, this is an interplanetary gear !" And the reason is anyone who has ever worked in Materials, knows that the surface atoms are extremely reactive, and if you put this in an oxygen environment, all these atoms would, you know, would oxidize, and you wouldn't have this structure anymore. The other thing is, there's no lubrication here, the atoms, one on one, actually like to bond. I had three reasons why it was an interplanetary gear : you had to operate it in an ultra-high vacuum, and I don't remember the other two, but it was absurd !

GS : Briefly, the Scientific American article starts an unusual paradox, if you look at boundary constraints, there's so much larger material strength. But this is the paradox, that we now, in quantum mechanics are understanding, in such a way that we can now start constructing better.

TE : Well you know, and I read all this stuff about carbon nanotubes, you know, having calculated the strength of them. We did iron whiskers in the 1950's ! They actually experimentally measured them, and it's not a theory, ok ? And actually, one time in my class, three years ago, I was pointing out surface tension in my welding class, and I was talking about Van der Waals bonding and stuff, and I pointed out that, you know, the strength of an atom-atom interaction is millions of psi, and that should be equivalent to the surface energy created and one student said "How do you do that ?" So I went back to my office, I had an hour after class, and I worked it out ! It's actually just, you integrate F dot dx to get the energy of the Leonard-Jones potential, and you compare that energy, per atom, to the area of surface, of what's the unbonded state. You predict that iron, to pull two iron atoms apart, F dot dx, that energy is equivalent to the surface energy created by iron, 1.5 Joules per square meter. You know, yes, I had to work it out, it took me an hour to work it out, mostly because I had to go back and remember my units conversion, right ? It wasn't a hard calculation. This is a freshman physics type of calculation. But the units conversion got me all screwed up. But it works out. You can prove, all these people are presenting this as if it's a wonderful revelation ! 50 years later ! People worked this out ! I don't know whether it was Cahn, whoever it was, but people worked this stuff out, I don't know, years ago. It's because they don't read the literature, or they need to sell something, to people today and say "I'm new, I'm different, I predicted carbon nanotubes are the strongest things going." You know, I got criticized once, because I said the carbon-carbon bond was the strongest bond. This was in some Technology Review article I wrote. And some chemist spoke to me and said "No, it's the silicon-oxygen bond in silicons." You know, one's like 2.2 eV and the other's like 2.3 ! Or 2.25 or something ! And "Oh ok, so I'm wrong !"

GS : Ok, quick comment and then I want to pursue this one step further. I don't know if you realize that this is something I followed in quantum chemistry. The Jones-Leonard potential has been derived, was derived for the first time successfully in the 1980's. And at that, only for helium.

TE : Oh yeah ?

GS : If you actually tried to do the derivation from first principles, you get totally wrong results. And they got it for helium, it was a huge computational endeavor. The problem is you have to integrate, average, across all possible orientations. So they finally broke it enough to say it actually works for helium.

TE : Because helium's symmetric.

GS : You got it ! Except it's not symmetric in electron orbits, so you have different orientation. Let me ask you a different question. Arne made me look at your curriculum. Which I guess has changed recently, and Suresh has changed it still further, but I'll leave that alone. What I noticed, and he was calling to my attention, is a bunch of solid-state quantum physics courses. Do you presuppose the material in those courses, in your classes, you are very seriously giving them quantum mechanics. Do you expect your students to understand that ?

TE : No. In fact, don't ask me to defend that new curriculum. That new curriculum is heading in the exact opposite direction of where I think the department ought to be heading. That curriculum was put together by some people who have never worked in industry and still think that we're producing PhD's to go on to academic jobs. As 10% of our doctoral students. 85% of our students go into industry. So our department, in their quest in this hierarchy of snobbery, likes to consider themselves, or they are more and more trying to consider themselves research or materials scientists. In materials engineering, there have been relatively few hires. In fact it's getting to the point where it's questionable whether we can even teach heat and fluid flow anymore. We were innovative in 1995 by requiring heat and fluid flow. We were the first Materials Department to even require heat and fluid flow of the undergraduates. But we're about one year away from having no one, except me, teach it, and I'm not going to. But they have not replaced the people, the materials engineers who could do that, and more and more, because all the students want to go into photonics. Which is one of these waves, I mean, this wave may be a fifteen year wave as opposed to a five or ten year wave, like advanced ceramics in the mid-1980's to early 90's. So maybe electronic materials is a longer wave and then biomaterials is coming along as a wave. But there's going to be something else. Whether biomaterials takes it over, you know, takes over electronic materials, but the industry is going to saturate. It's the old story of you know, the functionality... well I say old story ! Christiansen got his claim to fame for the Innovators' Dilemma, that the technology outstrips the need. And people are going to quit buying functionality that they don't need. Do you need a 1.8 GHz computer to do word processing ? Lets face it, most of the PC's in the world are just secretaries typewriters.

GS : Except for the internet.

TE : Except for the internet, yes. But, well, you don't need a, do you need 1.8 GHz for the internet ?

GS : Well they make sure you do by... put more crap on there !

TE : Well given that last mile speed, you don't need that !

GS : You're not really presupposing...well what you probably teach is practical, right ? You're teaching welding among other things.

TE : Well, yes, but I teach it from a completely different point of view, but that's only to graduate students. When I taught undergraduates, I used to teach the sophomores physical chemistry. And that we did expect them to have a good foundation in thermal and physical chemistry. And they were supposed to get it with mechanics in the old curriculum. And they were supposed to get a structural properties course, which unfortunately, we had some of our materials scientists think that teaching space groups was teaching structural properties. Well that was never... I mean I was on the committees ! Both the undergraduate and graduate committees, I was on the committees that formed the curriculum when I was an undergraduate student and when I was a graduate student. I served on the lunch committee and the Cohen committee. The idea is that you would give some student the appreciation for the types of structures over the scales of size. Well, it turns out that of all the people who teach the course for 20 years, we never could get anyone to teach it properly, until finally, Sam Allen and Ned Thomas wrote a book in our curriculum series. Which began to do it, and that's the first book, but it hasn't really taken off because frankly, there's not really any single materials scientist who knows all that material from the get go, from atoms to [Regie Blue], you know, if you talk about size scales, you talking about eight orders of magnitude ! Or seven orders of magnitude.

GS : Now, you're not presupposing...what about evidence ? In his undergraduate and graduate, David Parks tells me that in the graduate program, really does presuppose the quantum mechanics principles - in higher courses. I'm dubious.

TE : When they talk quantum mechanics, they're talking about the concept that electrons can tunnel through an energy barrier.

GS : Let me use mine as a philosopher now, my terminology. I easily see quantum mechanics playing a profound heuristic role and serving as the basis for computation. But that's a little different from the science of quantum mechanics. Actually infusing the discipline. Which is it ? Infusing or is it primarily heuristic and an underpinning concept ?

TE : It's conceptual underpinning. I don't even know if I would give it the glory of being heuristic. As a graduate student, I taught the chemical metallurgy course, which the first half of the course was Tom King, the department head, teaching blast furnaces. And the second half was Keith Johnson teaching quantum mechanics.

GS : (Laughs)

TE : And I said there's never been a broader course taught at any other materials department in the country ! We went from

GS : [To Arne Hessenbruch] You have to see a blast furnace to believe it !

TE : We went from particles in a box to blast furnaces all in one course, and I was the TA for it. Nobody remembers this, this was basically teaching two separate modules. But frankly, [Tom King] was doing the old, traditional "teach them what the practice is out there." And Keith Johnson had been hired, I guess he worked with Slater, but he was a chemical physicist. He was using the x-alpha technique, if you're familiar, this was a way of kind of, when computers weren't as powerful, of just solving a single atom and coming up with symmetric boundary conditions. As far as I understand. Keith never got into something that complex, because that was research, and I remember Tom King once saying that Keith had just come to listen, this was when Keith was coming up for tenure, and he was all excited because he just figured out why permanganate ion was purple. Somehow in the calculations he had found some energy band or spectrum that gave the wavelength of purple. That was about the strength of what you could do, is you could predict that "the sky is blue." Bob Rose used to joke at that time that the computational materials scientists were able to predict that copper melts below ten thousand Kelvin ! That was about the level of their accuracy in 1970 ! Today, it's not really quantum mechanics first principles, but using Thermocalc and things, you can actually predict the melting point of metals, complex alloy systems, 12 component systems, more accurately than you can measure them. You can predict them within ten degrees with a fair amount of reliability. That's not quantum mechanics. That's basically just taking huge databases of thermodynamic data and fitting and finding the best fit.

GS : Which to me is engineering science.

TE : That's engineering science. Yes, it's not basic science. If we go to what people do today, yes, actually, people use the old x-alpha technique as kind of a tool. They don't use it for undergraduates, but they use it for graduate classes now. People are trying to use some of these programs—actually one of these programs came out of the biology field— for first principle calculations. But there was a $50,000 program that Gerd got inexpensively, and he teaches a course on computational techniques in materials science. He's basically teaching them how to use some of the tools that you pull off the shelf. Physicists are developing them.

GS : I may try to take the course.

TE : I don't even know if he's still teaching it, but anyway. Basically, he's just pulling tools off of the shelf and showing them how to use them. It's interesting to me to see the tools the graduate students can pull off the shelf, whether it's Thermocalc or whether it's a first principles type of thing. The first principles things are certainly, as you pointed out, are coming up with very very simplistic models, but that doesn't mean that they're not useful.

GS : Well, let me now summarize. You said one thing earlier that I now want to understand. Mainly, the time is coming, for these calculations to become more and more pervasive. Fair enough. What it sounds to me, is the science side of this is in contrast to the metallurgists I grew up with. Now remember, what I know as an engineer dates starting in the 1950's. These metallurgists literally taught me on the spot. They wouldn't have known about quantum mechanics, or anything !

TE : They didn't even know "particles in a box," right ?

GS : They were in another world. What's happened, is the application of fundamental science to specific problems in the materials realm, there's been a transition from virtually no attention to the possibility of using highly current science in application, to a great emphasis on it. Is that a fair summary ?

TE : I think you're going back a little too much to the physicist, of what the latest thing is. I'll accept there's a ten or fifteen year delay.

GS : Ok. Fair enough. But twentieth century physics, fairly recent physics is being taught.

TE : Oh yes. I mean...

GS : And that's not true to the metallurgists who were coming up in the 1940's.

TE : In 1970, when I was taught, I was taught k-space, and reciprocal space, lattice to understand the band structure of metals. Which really was what Slater and others were doing in the 1930's. Right ? It made it down to the undergraduate curriculum, by 1970.

GS : Ok, that's impressive.

TE : It was just probably in the graduate program in the 1960's, and so the time lag might have been 25 years at that point. I would say the time lag now it ten to fifteen years. But it hasn't shrunk to three or four years or five years,

GS : And it's only when it shrinks down to something like that, that the possibility of feedback into the science starts growing.

TE : That's why the physicists look at what the materials scientists are doing, and they say, "These are not sophisticated models. What Gerd Ceder did is he's using models that are ten years old." Well why is he using models that are ten years old ? Well first of all, it takes about three or four or five years to recognize they exist, and then it takes a few years to learn how to use it, right ? And then by the time you use it, by the time you get a result out, it's ten or twelve years at the earliest ! Plus you have this kind of series of recognizing that technology exists, learning it yourself, and using it and applying it, and you have those three things, and that's going to take 12 years. I remember in 1984, when I worked for the Navy in Tokyo I went to Australia, and I met the guy who was the science master for Australia, and he happened to be a metallurgist. He worked for BHB. We were at a conference together, and he told me that the Australians had just done a study, to find that it took eight years for Australia to recognize—actually Australia was eight years behind in most of their science. Seven years of that was just recognizing that the work had been done somewhere else. It only took them about a year to catch up, once they recognize that the work had existed. But just sifting through the literature and realizing that over here, or at this institute in the Ukraine, or over here in Germany, or over here at Stanford or whatever, someone had come up with something really similar. It took them seven years to recognize these seminal contributions. Lets face it. They don't all come, they come from disparate places at disparate times.

GS : In physics, people are very aware of one another, of what they are trying to do in the backdrop. So there's very quick dissemination. Here it's individuals picking things up sort of in isolation, and playing with them until they become productive enough that it spreads. That's because you're not really doing research in these tools. You're doing research in the application.

TE : Right, and it may explain why [Bob Ranek], who was at NSF for like 30 years, kind of heading up a lot of their materials sciences, and he used to say, "Look. The physicists don't murder each other on proposals like the materials people do." Why ? Because the physicists, as you said, they all kind of know what they other guy is doing, and even if the other guy has a harebrain idea, you're a physicist, your kind of a liberal, and hey, you say "Maybe you'll come up with something." You don't have this arrogance that you know everything. In the materials science field, there's a few people who think they know everything, and no one else has ever learned anything. "Hand me down from on the high," you know ? A transfer of knowledge. It's a very dysfunctional approach to assume that all your colleagues are buffoons. Now it may be true that 98% of them are, but none the less, to assume that all of them are...

GS : Let me put the capstone on this line of discussion, and then start the second line. So if Bob Brown asked you, you wouldn't recommend moving the Materials Science & Engineering Department into the School of Science ?

TE : No.

GS : Is there anybody in your department who would be inclined ?

TE : Oh there are three or four very arrogant people who think that they are great scientists and great physicists, and what they don't realize, and Bob Rose (Bob was my assistant advisor) and I always talked about the fact that they are half solid-state physicists.

GS : What's the size of the department ?

TE : It's about 32 or 33 faculty. How many people did we train in physics ?

GS : PhD, graduate trained ?

TE : No I know. Not that many. Maybe two or three, I'd have to go back.

GS : Chemists ?

TE : Well, chemistry, you know, Gus Whit, who is retiring this year, had a degree in physical chemistry from Indiana. But most of them come out of Materials or Chemical Engineering departments.

AH : Wuensch is crystallography, sort of physics...

TE : Bernie had a joint... who's the great crystallographer in the physics department at MIT... [B.E. Warner]. Bernie did a thesis in our department, but [B.E. Warner] was his thesis advisor. Bernie's the guy who thinks that teaching space groups is teaching structural properties. I had to, as a tenured professor, had to mount a revolt. He was chairman of the undergraduate committee, he was head of the committee that created the curriculum. And I knew that what he was teaching was absolutely worthless to these student engineers. I mean if they were all going to go off and be physicists, it was probably the perfect course, but that's not what they were going to do. I had to lead a revolt. Bernie, who was usually a very kind and gentle person, Don Sadoway remembers it, one time I had finally brought it up again, and the undergraduates backed me up. None of the faculty dared to back me up, because Bernie is one of the most articulate people in the Department, and Bernie, when we had the vote, and the undergraduates on the committee sided with me—and the other faculty actually voted to make it a broader course rather than just space groups— and Bernie just lit into me, in front of the undergraduate students and everybody else. He told me how an ignorant welder couldn't appreciate blahblahblah

GS : [laughs] You're not an "ignorant" welder.
AH : When was this ?

TE : This was like 1978 or so, I was probably still an assistant professor when I had led this revolt.

GS : Tom's never been known not to hold back on a strong view !

TE : Hey, you know, if they didn't want me for a faculty member, they could have denied me tenure, and so what, I've got a life, I could go on somewhere else ! Which is what has bothered them ever since, you know ? Because they know they can't shut me up.

GS : Let me go to the other line. When Mel Bernstein talks about Materials Science (he was really the first person I was around), he taught at Tufts for a while...

TE : Where is he now ?

GS : [?]

TE : Oh.

GS : [Backow]...[?] He had the feeling that [Backow] was not going to listen to him and he wanted out. These are two people he knows pretty well...

TE : And he's absolutely right ! A single conversation with [Larry Backow] will tell you that he doesn't listen to what you're saying.

GS : I know, and that's what happened. A single conversation, in private, and he came out of that office and wanted out. When Mel talks about Materials Science, what he emphasizes, is the generality of materials over the word metals.

TE : Yes ?

GS : And to the extent that he was teaching a cute, a nice undergraduate course on materials, in which he emphasized the substitution of non-metallics for metallics and vice-versa. He went through the history of different bicycle materials.

TE : A typical approach. I've seen it many times, students like it.

GS : It's a good course and I'm very impressed by it. I'm curious about that in some ways, and I'll do it in my polemical way, which is probably surely wrong. As an outsider watching, of course you know I have a very slanted picture of the aircraft engine industry, and in effect applying the knowledge I got here to turbines, but generally, I got the impression that the metallurgists saw various materials coming to the forefront that might potentially replace metals. And they didn't want research on those materials to fall into other departments. They wanted to absorb it, but at the same time, the most widely used material in the world, concrete, they showed no interest in.

TE : Well, I think you're giving too much prescient knowledge to these metallurgists, ok ? I look at it as first of all, when our department was started, it was course 3. There was Civil Engineering, Mechanical Engineering (course 2 at MIT), and there was Mining Engineering. Now there's not a lot of mining that goes on in New England anymore. There's not a lot that goes on in the United States. But it was in 1888 that they added the title "Mining and Metallurgy." And you have to remember where metallurgy was, you had Bessemer. Who had come along twenty years before, and all of a sudden the steel industry was growing. Andrew Carnegie was the richest man in the world. He was the Bill Gates of today. So why did you go from mining to mining and metallurgy ? Well because metallurgy, the steel industry, was becoming the dominant industry. They were the semiconductor manufacturing industry of the day. And in fact even until 1961, remember when U.S. Steel wanted to raise prices and Kennedy had to stonewall them down, because it was going to cause worldwide inflation. It was like raising the price of oil, before the price of oil became the gold standard of...

During World War II, we bombed out most of the world's steel making capacity, so at the end of World War II, the United States had 75% of the world's stainless steel making capacity. Bethlehem and U.S. Steel had 40% of the world's steel making capacity between the two of them. You developed an arrogance among these businessmen that is unbelievable. From the days of Andrew Carnegie through Charles Schwab, who started Bethlehem, through, who was it Martin ? Well, anyway, the guy that ran Bethlehem through the depression. It turns out that during the depression, the ten most highly paid executives in U.S. industry, six of them were at Bethlehem Steel. And I can't remember the guy who ran Bethlehem Steel at the time. He made a profit when Bethlehem lost money during the depression, because he got paid a bonus as CEO, for every pound poured, every ton poured. It wasn't how much money they (the company) made. When I joined Bethlehem Steel in 1974, they had just had their most profitable year ever, 1973. They had been almost bankrupt in the late 60s, when they built the last integrated steel mill in the world to be built by a company. Every one since has been built by a nation. Bethlehem built Burns Harbor Indiana plant.

GS : You realize I worked on that.

TE : Did you ? Ok. So anyway, you know Burns Harbor, but Bethlehem was close to bankruptcy in the late 60's, but then when Burns Harbor started, it was an efficient mill. I remember in 1975, as a "looper," A "looper" was... Nick Grant had been a "looper" at Bethlehem Steel. They had the "loop" course, and back in the 1930's, late 30's, when Nick Grant went through it, he had been an undergraduate at Carnegie-Mellon before he came back to MIT.

GS : This is a term I don't know.

TE : The "looper ?" They had the Bethlehem Steel loop course, it was very famous. They took all their college graduates, and for one year, they would put them six weeks in the blast furnace, six weeks in accounting, six weeks... you did these six week stints for a whole year, until as a management trainee, you learned the entire loop of the company. You couldn't go through the whole thing, but you went through like eight of these things, eight of these modules. Then you were a "looper." I was hired, I was one of 500 college graduates, hired into the loop course. Well, when I went into the loop course, it was no longer a year's training. I was hired in the research department, and I had been working there for seven months. So when the next summer, they ran it for 2 weeks at corporate headquarters in a great big auditorium. And in the mornings we would have lectures from the vice presidents. Tells you something about 2 weeks worth of vice presidents, about how many vice presidents we had. And in the afternoons we would take tours of the Bethlehem plants to see how steel was made. With our white hard hats to show we were management and such. We would just walk through like a bunch of prima donnas through the steel plant. That was the loop course and how it had changed. But I remember the vice president of finance gets up, and he says "It doesn't cost Bethlehem Steel anything to make steel because our coke ovens were built in 1911 and our blast furnace was built in 1912, and they're fully depreciated." and out of 500 ignorant little people who were supposed to be impressed, and I had the audacity to raise my hand and said, "I don't understand why it doesn't cost any money to make steel just because something's been depreciated." And his answer was, "That's because you don't understand finance." And, you know, that was true. I did not understand finance. But it wasn't until two years later that I took a finance course at Lehigh, that I realized that he didn't understand finance either ! You don't save money by using something that's old and low-productivity just because it depreciated. On the books, on his books he might but in reality, you don't. And that's what killed the American Steel industry. But the point is why did we take metallurgy out ? The department over there has got like 23 endowed chairs. Something like 17 of them come from the steel industry or steel people. Ok ? If you look...

GS : You're even less that extreme at Carnegie-Mellon.

TE : Oh yeah.

AH : "Over there" being the department...

TE : The department, yes. In our department. And one of them is actually a chair of ferrous metallurgy. This is a guy gave four chairs, a Greek steel man, he gave them when I was department head. The first chair, or two chairs, he gave two chairs. He actually gave about 7 chairs to MIT, one in Chemical Engineering, his Master's thesis advisor, and he upgraded a junior chair to a full professor chair. Then he gave four million dollars with which we created two chairs, the [Metoulla ?] and the [Establa Solophotus ?], two chairs he gave for his parents. And he gave those gratis. No strings attached, didn't have do anything. When he came in to form the [Tom King] chair, of course Tom King was his thesis advisor, and the chair in his and his wife's name, and [Vicillian ?], [Venet ?], and [Solophotus ?]. The Tom King chair is a chair of metallurgy. And the [Solophotus] chair is a chair of ferrous metallurgy. I called up Bob Brown, after he came into my office and said he was going to give me three millions bucks, after he had already given us four million bucks, and this was like a year and a half later, and I said, "Bob, can we accept these ?" And Bob said, "Oh sure !" Bob has no compunction whatsoever. He would take it, and what does he care ? Screw him ! Solophotus will either be dead, or if he comes back, he can't get his money back. That's the ethics of Bob Brown. And that's the ethics of MIT, so far as that goes. But that's one of the things, I mean I always tell people that's one of the reasons I stepped down. There's a thousand reasons I stepped down. But that's one of them ! I know, and Vicillian calls me, every time he comes back into the United States, because he realizes that he can trust me, and I say, "Vicillian, you know..." what I did is, I created a good friend of his, [Claude Lupus], Who was an MIT graduate student at the same time. They're both of Greek origin. When Claude's mother was dying in Egypt, and he was living in Australia, he had to fly through Athens to get to Egypt, and he stayed at Vicillian's house. This was back in the 1970's. They're best friends, and I got Claude, well Bob Brown killed it, but Claude was a full professor at Carnegie-Mellon, and went off to Australia and worked with the World Bank and other things. He had a degree from France, it was the equivalent of a doctorate in economics before he came to MIT to get his doctorate in metallurgy. He made full professor at Carnegie-Mellon and went off to become the advisor to the CEO of [A-Max] or whatever, and worked in industry, basically as a consultant for the World Bank type of things, and made mega billion dollar projects around the world for twenty years. He wrote... at the end of that, wrote a textbook that's being used at about half of the materials departments to teach graduate thermodynamics. He also won an award, a practical award from AIME, ok ? He wanted to come back because his kids were going to start college in the United States, and I figured this was the perfect person, sixty years old, twilight of his career, make him a professor at MIT. Bob Brown wouldn't have it. It was basically, you know, give this guy...well anyway, what he did was let me make him a visiting professor for five years. So Claude's treated as a second class citizen, but he has the name [Vicillian Solophotus] on his chair ! And Claude is as much as a physical metallurgist as anyone else. Vicillian is very happy, but what happens when Claude's five years is up ? I don't have to find anybody, I'm no longer part of that ! Well it's not as if Tom Eagar's going to be quiet about the fact that MIT is going to use this to hire some photonics person in the chair of ferrous metallurgy ! Ok ? It's deceitful, it's dishonest, it's unethical, I don't care what you call it, but it's the MIT way of doing business.

GS : Can I read you correctly ? This is still...
AH : Yes, I have it all on tape, but you haven't signed anything yet !

TE : I'll sign it !

GS : So there's not a metallurgy department in a very real sense ?

TE : No, no, no. They have not hired, actually, they did hire one metallurgist, who will show up in the next year, but that's probably the first metallurgical hire in ten years. Mert Flemings actually fought very hard, got a lot of flak from the steel guys, to drop it down to 25% metallurgists. When I was a student it was 70% metallurgists, 25% ceramists, and 5% polymer people. Or polymer "person," I guess. Just one or two ! And they wanted to build up polymers in the 70's and 80's, and then Flemings actually, for all of my problems with Mert Flemings, he actually did a very good job of balancing it so it was 25% electronic materials, 25% ceramics, 25%..., well he never got it down to below about 30% metallurgists, and 20% polymers people. And, well, I mean I completed it. And at some point while I was department head, we were 25% of each. But it never had this thing where the steel guys wanted to bring the other things in—the steel guys wanted to keep the other stuff out ! Why is concrete out ? Because it's a competitor to steel !

GS : I understand. But I gather there's somebody in Civil Engineering taking a Materials Science approach to concrete right now.

TE : Well they have to, because there's more tons of that used than steel. However, they've hired several people in that field, but it's very hard for them to get tenured, because you have people like Bob Brown at the top, who says, "We don't want someone in concrete," just because it's one of the most heavily used materials, and it has the potential to be improved dramatically. Ok ? And the science has been done to show that, now you just need someone to show and prove the processing economics to do that. But Bob Brown wouldn't be interested in that because he gets his Materials Science off of the front page of the Wall Street Journal.

GS : Let me try something. Of course his background is applied mechanics.

TE : Yes, but he considers himself a Materials Scientist, because when he first started Mert Flemings gave him some money, some seed funds out of the Materials Processing Center, to do some problems on silicon crystal growth. So Bob Brown thinks he knows more about Materials Science than I do, ok ? Actually, he thinks I'm a dinosaur in Materials Science. We actually shifted to 15 or 20% metallurgists, and that's mostly just because some of us can't wait until we die. The department now is trying to shift to almost all electronic materials and biotechnology. Which is interesting, because when I started out as department head in 1995, I determined that we wanted a soft-tissue biotechnology...They had an opening, supposedly, for a biomaterials person, but Mert Flemings and everyone else in the department was thinking what I call a "hip corroder." Basically, looking at vitality and how metal implants corrode in the body because that's all they ever knew, from the 1960's on. That was what they thought of biomaterials. I went, and I talked to Doug Lauffenberger, and I realized the type of stuff that Bob Langer's doing, the type of stuff that they're doing in Chemical Engineering on soft-tissue engineering was the real future. And that's where people would be using the principles of polymer science. It took me two years of bringing in candidates for a faculty position in biomaterials before the faculty finally got a vision. We must have brought in a dozen, some of them very senior, and some of them, well most of them junior, candidates. And I was getting faculty coming to me and saying, "What are you bringing this person for ? This is a Chemical Engineer, they don't belong in the Materials Department !" It took me two years, and all of the sudden, after about two years, the faculty had the light hit them. They realized that soft-tissue engineering was what really the future of biomaterials is, and so now, they're running "whole hog" into it. The pendulum swings too far to a certain extent. But none of them, I mean fortunately, you know, the wicked leaders, he who they despise, the good leaders, he who the people revere, and the great leaders, he who the people say, "We did it ourselves !" I actually was the great leader in biomaterials in that department, because nobody in that department would now associate me as the person who forced them into soft-tissue engineering. But I fought them for two, two and a half years !

GS : Ok. I want to continue this line, but I want to do something different. I mean, from my background, when I hear ceramics, when I hear composites, my eyes tend to roll.

TE : Well, same here ! I wrote articles on that !

GS : Well, you know, Rob's article on the heart valve is one I constantly pull out, and tell people these are materials whose time has not yet come.

TE : And will not come.

GS : And will not come for forty years ! Well that's Rob's view. But now, David Parks offered the following description of the change in Materials Science. He said, "The old organization," and he was at Illinois, "Was a group of specialists defined by the Material they worked on."

TE : Yes.

GS : And a curriculum built around the individual. And that's just not true anymore. What you're doing is generalizing across materials constantly.

TE : Yes. That's true, and that came from... it came actually first out of the [Wench] committee. It was led in part in the background by Morris Cohen. If you want to go up to Swampscott, you might want to interview Morris Cohen. Morris, who was a steel man, he was revered by the steel industry, was the guy who led the charge nationally to take it from a metallurgy field to a broader field that covers Materials Science and Engineering, and looked holistically at the structure and properties relationship you had been looking at in steel and copper for all these years. The same things apply to other things. Which is why I laughed at Buckytubes being so strong when we were doing iron whiskers in the 1960's and the 1950's.

GS : I had lunch yesterday with [Dudley Hershey], and he of course, created the technology...

TE : You know these are people reinventing the wheel. Morris actually had the vision, and through COSMAT, he pushed that vision that it really was a holistic field of Materials Science and Engineering. I think, although you'd have to talk to Mert and Morris I think [Herb Polyman] was one of those, where all but everyone hated the man. And I only met him at few times in my life. He was one of the more arrogant people, but he was at MIT,

GS : Yes, I understand.

TE : But not in the Materials Department.

GS : He was incredibly arrogant from everything I hear.

TE : He belonged at Harvard. I mean there was absolutely no question.

GS : See I saw traces of him at GE.

TE : Well, you know what I always say. MIT is the second most arrogant school in Cambridge. You can quote me on that too.

GS : You don't have to be quoted, everybody knows that ! That's simple truth !

TE : So the industry in the 1960's and the 1970's was still feeling they were on top of the world. And I remember when I went to Bethlehem Steel in 1974, as a young employee, they had 25% of the world's steel industry sales, where they had 75%, but the guys that had been hired after World War II were now the managers 25 years later. They still thought in terms of "We control 75% of the world's steel industry." But they only had 25% of it, but they had the arrogance to try to do it. And that was the beginning of the end of the steel industry in the United States. They would not change, they were proud of their 1912 blast furnaces, because that was what made them profitable for all they knew. They were idiots, they were morons, I don't care what everybody else says. They were not looking at new technology. They were living in the past, they were flying, they were taking corporate jets from Bethlehem, Pennsylvania, down to Florida on the weekends to play golf. I can give you all kinds of stories. Just total corruption, I mean, well I don't know about "total corruption," but they were not businessmen. They were just people who had worked themselves by the corporate lobotomy to the top of the heap, and now they were taking all the perks they could. And I could tell you, we could spend hours on the perks these guys had. The automotive companies, and Kodak, and all these others never topped the steel company in terms of taking care of their executives. So those steel companies Were very upset for the next 15 or 20 years that MIT and other people were moving to this more holistic view of Materials Science, rather than metallurgy.

GS : I would think they resisted perhaps ?

TE : Oh yes. And I don't think we were the first department to change to "Metallurgy and Materials Science" as the title.

GS : No, you weren't.

TE : Ok. There were one or two others, but it was only because they didn't have as many politics to fight at the other schools that did it. I think you'd probably find that an individual at each one of these schools who was on the COSMAT committee and stuff, and so they did it earlier than we did, but only a few years earlier.

GS : It's interesting to know that the steel people resisted. [Bernstein's] an interesting case, because of course the handbook of steel, he co-edits and co-authors, and he had become just an outspoken proponent of broader materials.

TE : Well, it's a no-brainer ! I look at what the polymer folks are doing today, and I say, "They've discovered alloying." Ok ? What was discovered 150 years ago, they've now discovered !

GS : Well, 1500 !

TE : Well 1500. Well in terms of starting to understand, but yes. We've been doing it for years before, but we didn't really understand what zinc did to copper. But in any case, what it was that it was harder to alloy in polymers. You can't just throw them together, you actually have to synthesize them together as block polymers, but that's nothing more than alloys, the polymer analog to alloying in metals. And now, guess what ? Instead of monolithic silicon, they're going to silicon germanium, and the compound semiconductors and stuff. Well, surprise surprise ! When you marry two materials, you can actually enhance some properties at the expense of some others, which is something people don't always realize. That you don't get your bang for your buck in every area.

GS : There's no free lunch.

TE : There's no free lunch. Anyway, so the metallurgists still dominated the industry. A lot of them were wealthy and gave a lot of money to the department to create chairs, but they have been somewhat chagrined to see that the department shifted. Although in the late 1990's, many of them actually have acknowledged the wisdom of the department for having switched. Because most of the steel guys realize that the steel industry is gone. You have to remember that the steel industry was where our students went ! Where did Tom Eagar go when he graduated ? Bethlehem Steel ! They hired 70% of the graduates, and that's why 70% of the faculty were steel people. Why is the department swinging towards electronic materials and biotechnology ? Because that's where they're hiring students. The problem is the faculty still think that they're producing professors. Not students for industry. And the faculty don't like to think of themselves as engineers. My tenure case, one of the letters, and I know the person who wrote it because I got to read my whole tenure case when I was department head. This is one of my colleagues on the faculty. He described me as a "pure engineer."

GS : I would describe you that way.

TE : Yes. I describe myself as a pure engineer. I am proud to be an engineer. I'm one of the only people I know who is proud, working in academia, who is proud to be an engineer. I've always said that it would be wonderful if more than 20% of the faculty in the School of Engineering at MIT were engineers !

GS : Parks is another one.

TE : Parks is another one. Yes, he's one of the 20%. Now I also say I wouldn't hire more than 20% of my colleagues as a consultant ! Most of them are scientists who wouldn't be able to figure out any complex problem, make a decision on it, in the face of uncertainty, and have a chance of being right. I'm a pure engineer, and so I've accepted the fact that I'm a pure engineer. I'm proud of the fact that, although I don't like to use the proud word for religious reasons, but I actually am "pleased" to describe myself as an engineer. And I've come to realize that I am in a tremendous minority among academics. And it has created, I'm somewhat of an outcast because of that, or looked down upon by these other people. But I realize they're all third rate scientists. The people in the engineering schools who like to parade around pretending they are scientists, if you took them into a physics department, they'd be laughed out of the room, ok ? And anyone who looks at it objectively knows that. But these people, I mean some of them have a tremendous amount of arrogance. They think that they're doing the most wonderful stuff in the world, and all they're doing is second rate engineering. If they would recognize they were engineers, and accept it, and be pleased with the fact that they are engineers, they would do a much better job than they do. But they like to think of themselves...

GS : You're preaching to the choir.

TE : But you understand that this hierarchy goes from the scientists at the top, down towards the lower lever, the engineers. What I learned, in biotech, is that clinicians are beneath the engineers. Ok ? Because they are totally empirical. But there are very valuable clinicians out there. The thing is all these people add value to society, but what irritates me is that they can't respect each others' contributions.

GS : I have one last question, and then I'll be... this is the sort of thing you like. Is to hear this hierarchy. I have a minor question, in a way it's a selfish question. They pay very little attention to the mechanical behavior of metals, thinking of fracture mechanics. Which of course is the one area of your entire field that I know little about.

TE : That's because the scientists, don't even...do you know fracture was left out of the graduate curriculum 20 years ago ? And I brought it up in a faculty meeting and [Reggie] looks at me and says, "Yeah you're right !" I said, "We're not going to teach fatigue or brittle fracture in our graduate curriculum ?" And everybody kind of looks around the room and Reggie looks at me and he says, "Yeah you're right it's not here !" No one in the room had even realized they had left it out.

GS : Of course, you know my view is you learn from failures more than anywhere else in the real world, but you know that.

TE : Yeah, I know that.

GS : Now it's a hybrid field, because it's both Mechanical Engineering and Materials Science. Is that right ? Should it be a hybrid field ?

TE : I actually think it's one of the strengths, in fact as a freshman, the way I chose Materials Science and Engineering, first I happened to have 3.091 with [John Wulff], and I had [Jack Hash], who won the Goodwin Medal as the best TA at the institute. And my house tutor was a Materials Scientist. But the real reason I chose it was it was the only department in the school of engineering that had both science and engineering in the name. I didn't know if I wanted to be a scientist or an engineer. I didn't even know what a scientist or an engineer was at the time ! But I knew I wasn't ready to make the choice. And because of a host of reasons, but one was because science and engineering were both in the field. And I actually think that's a strength. I wish the faculty actually recognized where they lie on the spectrum of science and engineering. They are all on one end of the engineering side of that spectrum. What they consider Materials Science, the physicists would consider applications. They don't understand that there is this other half that goes all the way back to the fundamental science. You're talking about feedbacking control, well that's because they don't even recognize that Materials Scientists think that they are fundamental physicists, ok ? And the fundamental physicists look at them as these applied guys, and so there's a total disconnect. There's no feedback at all, and maybe you could speed things up a little in the world if maybe they developed a little respect for each other. But that's the whole respect thing that irritates me so much. These people don't respect other people's contributions. I'm used to people in my department looking at me as the far end, the engineering end of that spectrum. And I don't mind being there, but I have had a lack of respect from my colleagues for the work I do because of that, and I think that John Wulff can go back and point to that, and there's some other faculty who could go back and point that they were on the further engineering side. It doesn't bother me, because I got a better record than any of them. Ok ? So I can kind of thumb my nose at them and say, "Screw you !" But it would be a heck of a lot better if the collegiality were better.

GS : The collegiality is pretty good though. The mechanical behavior of materials with mechanical engineering, and of your people, I hear nothing but respect from [McClintock], Parks, yes, all of those guys.

TE : Subra has his own appointment over there, and he graduated from that department. And I think they...

GS : That's the problem. It's that that department doesn't know very much metallurgy.

TE : You said [Rob Ritchie] ? Yes, he was in that department, and he is very much in my work, he's more of a mechanical engineer. I think they get along. As well as anybody. And they had a certain respect for Reggie. Well, they did.

GS : But [Reggie] had a lot of respect for them.

TE : Reggie had a lot of respect for everybody. Reggie was one of the few people, who, you go around the country, and everybody asks how he's doing, ok ? He's genuinely loved by many many colleagues. I keep trying to get [pointing to Arne] his counterpart who's French, Bernadette, to interview Reggie in French, because I think they would hit it off profoundly. But because he's not a central figure in Materials Science, as you look at the literature, and they don't realize that he's a giant ! In fracture mechanics.

AH : Well, we're not just interested in the central figures.
GS : I understand, but Reggie would be a very interesting person, especially with her interviewing him, with his Parkinson's disease, his English is really difficult.

TE : Reggie bridged Mechanical Behavior and Materials extremely well. And he is a wonderful person, he respects everyone, and therefore had a lot of respect from a lot of people. But within the materials community, he was looked down on for the quality of his work.

GS : That's strange.

TE : Well that's not strange, he's at the engineering end of the spectrum !

GS : I know, but his work is a model of excellence.

TE : Well, still, I could say the same thing about mine compared to any colleague I know in my department, ok ? and I'm not trying to be arrogant here.

GS : Well, I know, I hired you !

TE : You can walk through my office and look at the awards up there ! And that's another thing that maybe we ought to bring up. You mentioned that at other schools there was one or two people. That is the model of Materials Science. Back in the 1940's and 1950's, and I can't go back any further, from what I gather from people, in the 40s, 50s and 60s there were five or six "dons". There was Morris Cohen in physical metallurgy, there was [Norten] in x-rays, there was, it became, Kingery in ceramics, there was [John Chipman] in chemical metallurgy, and there was the other Norten in physics of solids, the two brother Nortens. These people controlled the department. There were five or six fiefdoms in the department. They told the department head who they wanted to hire as junior faculty, they typically would hire two junior faculty to compete with each other, and these guys were basically slaves for the don, and they would cast one aside or both aside when it came to tenure time. [Ken Russell] likes to say that he was the guy who broke the system, because he and [John Breetus] were hired in to work with Morris Cohen and [Ben Averback]. John Breetus was, well, Tom King basically chose Ken Russell over John Breetus, Breetus is now at [Olin], against the wishes of the physical metallurgists. So Ken likes to say he was the guy that broke the system. Why did Tom King do that ? Because he and [John Elliot] were hired in to be John Chipman's gophers back in the fifties. And John Elliot had risen to the top, but this was a case where both of them got tenure, and Tom King actually went on to become department head, and he wanted to break the system. That's the way Ken Russell tells it. Tom Eagar likes to say that he was the first junior faculty member who refused to go on and work as a slave for a senior faculty member. I was offered the opportunity my first year. My first year budget was fifty dollars, and we can go through that, well actually I'll tell you this story, because this is on tape, you might as well hear it.

AH : Exactly !

TE : I was hired in to fill [Bob Moravian's] spot. You know Bob Moravian ?

GS : Yes.

TE : Bob had been told he wouldn't get tenure if he stayed in solidification, the same area as Mert Flemings. I was a graduate student at the time, I was going to borrow a strip chart recorder from him, and I had worked in his lab with Flemings back when I was an undergraduate. I was a graduate, and I needed to borrow a strip chart recorder, and I went to Bob's office, he wasn't there, I walked out and here he is coming up the steps from [Walter Owen's] office on the third floor, we were on the fourth floor. He walks in, and I say, "Hi Bob," and he says "Hi," and he walks in and I follow him into his office, and he's literally picking up books and throwing them across the room ! Bob was never a very calm guy ! And I said, "What's the matter Bob, you look upset ?" And he says, "You're damn right I'm upset, you know what Walter Owen just told me ?" And I said "No, what did he tell you ?" And he said, "He told me that if I stayed in solidification I wouldn't get tenure, but if I switch to some other field like welding, I can get tenure." Because MIT already had Flemings, who was only in his forties, and we didn't want two people in the same field. I said, "Well what are you going to do ?" He says, "I'm not going to switch to welding, I'm going to stay in solidification !" And I said, "Well then you won't get tenure ! Can I borrow your strip chart recorder ?" And two years later, he didn't get tenure, he went to Illinois, and they hired me to fill the slot.

GS : Welding.

TE : No, no. They didn't hire me to do welding, Nick Grant wanted me to do powder metallurgy and become his gopher. Mert Flemings wanted me to run his laboratory in solidification. But I knew that welding was a possibility and they were interested in that, so I basically said I wasn't going to work for anybody, because I had seen what had happened to these people when I was a student. And I didn't work for anybody, and they basically, within the first three months that I was on campus, the department wrote me off. And they gave me a secretary, who was on the fifth floor of building 13, I was on the first floor of building 8, had the little short door (if you know the short door). That was my office. I was sharing it with a graduate student. He got the better chair because he had been there longer, ok ? And had this old desk from the nineteen tens or something. I went to [Joe Docey] and I asked him, "Can I get some decent furniture ?" Because this was graduate student furniture, basically from the graduate student office. In any case, they gave me [Kathy Liden] as a secretary. Kathy Lidenwas a wonderful young women, but she was not too bright. She had been John Elliot's secretary, and he was over in Japan, he called her up long-distance, which back in the seventies was a big deal to call long-distance from Japan, and he says, "Send me this manuscript immediately !" This was before we had word processors or email. So she sends it to him, surface mail ! Kathy, well that was kind of her level of intelligence. And I was behind Ken Russell...

GS : These things don't get...

TE : I was behind Ken Russell and [Joel Clark], I was third in line. Joel Clark was another assistant professor, Ken Russell was a professor. They were over right next to her. This was before word processors, and I would handwrite out something, and she was supposed to type it up. I could write a three line letter and it would take me a week to get it back. Anyway, so Kathy came down one time to give me back one of my short little letters, and she says, "Oh Professor, what account do I charge your stamps to ?" I didn't even have an account, because in the old days, you always went around in one of these fiefdoms of one of these dons and they took care of you. Well I hadn't been willing to go along with this old system, of the fiefdoms so I had nothing. So I went up to Joe Docey, who was the administrative office, and Joe refuse to admit this anymore, and I said, "Joe, I don't even have an account number to pay for my stamps !" And Joe kind of hems and haws and says, "Well Tom, why don't you go ask some of the secretaries and they'll give you some." I'm supposed to go beg, as an assistant professor my job is to beg for stamps from secretaries, alright ? So I immediately go across to Walter Owens office, he's the department head, one of the three times I saw him before tenure. And I said "Walter," I gave each one of them a different problem, "I don't even have an account to pay for my long distance phone calls." And Walter thinks about it and he says, "Well, we'll give you an advance on your [Deserd] liaison program funds." So he's going to give me a loan on what I can earn. That's discretionary folks, ok ? So I went up to Mert Flemings, who was head of the committee that had hired me, Mertie had always liked me as an undergraduate when I worked in his lab, he always thought I was a Senior when I was actually a sophomore. That's what scared me away from working in his lab ! But I used to fix all the equipment, and the graduate students all liked me because they would break the equipment and I would fix it. Anyway, I go up to Mert, he's sitting on a million dollar a year DARPA contract, which was a lot of money back then, and he's got the only chair in the department, the ABEX chair. And I go in, and he'd hired me, he felt some responsibility at that time, and I said, "Mert, I don't even have an account to Xerox my proposals !" And he hems and haws as Mert will often do, and he says, "Well Tom, I'll give you an account number, but let me know if you spend more than fifty dollars." That was my first year budget ! Ok ? As a faculty member. I went back down to my office, that little door, and I sat there at my desk and I looked around at the walls...

GS : You didn't throw books ?

TE : I didn't throw books, I said, "Oh. So that's how it is. It's sink or swim." And I swore to myself, "Ok, it's sink or swim, we'll see whether I can swim or whether I'll sink, but if I do swim, I'm going to make sure that no junior faculty member ever has to go through this again." So anyway, I like to think that I broke the system. And the way I broke the system had nothing to do with me necessarily. In 1980, or 1979, I got my first ONR contract in 1977. My first contract, August 1st 1977. One year to the day that I had actually started on campus. And two years later, [Bruce Batuddle] at ONR, my contract monitor, calls up and says, "What would you do with half a million dollars a year ?" Well, that's a lot of money back then. What was happening is they were starting to get an increase in their ONR funding, but they couldn't hire any new contract monitors, so ONR had decided they were going to pick key areas of interest to ONR, and put a big slug of money in. And the first one they did, they did it with [Newnam] and piezoelectric materials at Penn State in 1978. And the second one, they chose an untenured, assistant professor...

GS : But on a topic of great interest...

TE : But on a topic of tremendous interest and at a university where they would love to see some students coming out in that area. And it turns out I only got $405,000, but nonetheless, all of the sudden, come 1980, I had a DOE basic energy sciences, an NSF, and an ONR, and I had $600,000 a year in research, which was only topped by Harry Gatos and [Kent Bond] in the department. And they both had junior faculty runts working for them, and big organizations and everything. I had more money per individual manager than anybody in the department. Mert Flemings was starting the Materials Processing Center, and he came over and begged me to put my contract through his center. Because that would all of the sudden show his center, he had a $360,000 NASA grant, if he had a $400,000 grant from me, he would all of the sudden have a nearly million dollar center overnight. He was begging me to put...

GS : You see the irony of this, given the questions of the website, is you're talking about a very complex social-political structure in this department. It essentially has nothing to do with the issue of Materials Engineering versus Materials Science. It has to do with the hierarchy of MIT, whether wrong or not. The obvious question is whether this is peculiar to MIT, or is this just a distortion ? Now at this point, I basically have to drop out for two reasons. I've got a board meeting, but has this been useful to you ?
AH : Oh yes, very useful. Very useful.
GS : I apologize for taking...

AH : Are you in a rush ?

TE : I'm going to have to leave in a little bit, I was supposed to be on the 10:45 but it was cancelled this morning, so I'm taking a later one. But, no, we've got a little bit more time actually.

GS : You want to ask the question, I see you've prepared...

TE : He's got characterization in here !

GS : That looks like a damn good book.

TE : It actually does.

AH : There's actually very little characterization in it.

TE : Well it says optical microscope, that's Sorby. He doesn't have x-rays in here, but he does earlier have Braggs...

GS : Yes. [Grines] are featured in chapter 30.

TE : No. R.W. Cahn is one of the great guys in Materials Engineering and so forth. And he's also a colleague of Morris Cohen's.

GS : [To Arne] Have you interviewed Morris Cohen ? [To Tom I want to thank you.
AH : No. This is actually something I'd like to do.

TE : Well you better do it soon ! I don't know really how much of this does go on to other schools. We produce 15 or 20%. Actually we produce 15% of all the doctorates, or we did, in the country, so I would expect that some of this probably gets carried over.

AH : I'm sure it does. That's the way of the world.
GS : Well, MIT... you should understand, I'm on the visiting committee at Caltech, MIT's is very very different from other schools. The department heads have incredible power.
AH : But political structures have an impact wherever they are.

GS : Fair enough. David's the one who made me realize that book existed. You'll see my pad. It has [Jed Buchwald's] name on it.

TE : Ok, well good to see you again.

GS : It's good to see you, and I may get you involved in this [world of steel]. The problem is to figure out why the step is vital.

TE : Oh, ok. [?]

GS : Yeah, but they're doing...getting 40,000 psi...

TE : So what are your questions ?

AH : Well, one of the things that I would like to get at is the impact of the processing on the field as a whole. Because while I tend to get stories coming from the other end saying about the impact of the development of the theories and so on. We've talked a lot now about the institutional inertia perhaps, something like that ? But a lot of the story of the field of materials research is really driven by market, by processing, and is a demand rather than a supply story.

TE : That's definitely true industrially. There's no question about that. In terms of the field being defined among the academics as having processing, as much as he and I don't get along now because of the way he treated me as department head, Mert Flemings really is the guy who has carried the banner. You have to understand, Flemings was not the brightest of students. He was ok, but he started out, and there was a guy named Taylor (I'd say Frederick, but it wasn't Frederick Taylor). Anyway, Professor Taylor in the Materials Department. Flemmings and [Dave Bergoni] ; and Dave Bergoni's and interesting person, you should talk to Dave. You've have probably come across his name. He was President of Case Western Reserve. Actually, his MIT number is [...Eagar writes number down...] (Because Dave is a very thoughtful guy) I'm pretty sure that's it. 4252. Dave and Mert Flemings and another guy Ed Hucky, were three roommates as graduate students. And they all worked for Taylor, who had the foundry. And Taylor had come from industry and had fantastic industrial contacts in the foundry industry. MIT had a foundry, they could melt several tons of steel in their foundry. It was on the top floor of building 35. They had a weld lab at one end, which was [Mel Adams], and they had Taylor's lab at the other end. And Taylor had a consulting business. It was quite a lucrative business, and it turns out that Dave, well they all graduated, and Hucky went to the University of Wisconsin at Madison I think, as a faculty member, Mert went off to ABEX and then came back two years later, working with Taylor. Dave Rigoni went off to, I can't remember where he started out, but he was dean at Dartmouth, he was Provost at Michigan, he was actually the guy who gave Chuck Vest his tenure at Michigan. When Chuck Vest was offered the job at MIT, he called up Dave to find out whether he should take it. I've heard this from both Chuck Vest and Dave. And Dave says, "Well there's two reasons why you might consider it. One, is they don't have a medical school, and two they don't have a football team." Anyway, Dave ended up as President of Case Western Reserve University, and then in his mid-fifties, he actually sort of got kicked out, I don't know the details at Case Western, but he sort of got pushed aside. He came back to his friend Mert, and he got an appointment as a senior lecturer, and he wrote the two undergraduate books in thermodynamics, Dave and I used to teach thermodynamics together to sophomores. And anyway, Dave will know some of these stories and stuff, back from the fifties, and he's a very thoughtful guy. He's not a typical metallurgist, he has been at manager at the universities, and I actually have a lot of respect for Dave. So he would teach his thermo in the morning, and he'd do venture capital in the afternoon. He's now seventy years old, and he still does his venture capital, but he no longer teaches for the last four or five years, but I think he probably still has a phone number here at MIT. You can leave a message and it will actually probably give you his venture capital firm in Wellesley. But Dave's a very interesting guy, but in any case, Flemings, the three of them used to go, these guys used to go out and do the consulting for Taylor's business. ... Mert was brought, Mert was kind of working along the old Taylor-ism stuff, as a young assistant professor working for...Taylor who was one of the dons, one of the bigger dons, but you know Mert was the junior faculty grunt working for him. And when Taylor died, Taylor had done very industrialized, very applied research. The dean at the time, Gordon Brown, a New Zealander, a prim and proper New Zealander supposedly, he was the guy who took MIT into engineering science in the late 50's. Around the time of Sputnik and everything else. And basically, Mert was brought in and told by John Chipman, who was department head, and sort of like Moravian, said, "If you stay in the foundry business, you won't get tenure. You're probably not going to get tenure around here because we don't want this kind of applied engineering science." Mert actually has told me this story, he went home, and he said that night, he was basically told he wasn't going to get tenure because he was in too applied of a field. He's told me the story. He went home and he that night decided to get rid of the huge furnace, you know, and just turn the whole thing into solidification science overnight. Because otherwise he wasn't going to get tenure. So he basically threw out the Taylor empirical stuff, and he rebuilt it, and he really built up the field of solidification science, which is, well he followed along some things that [Guy Rudder] and [Chalmers] Rudder and Chalmers were up in Canada. Anyway, he kind of followed along some of the stuff that they had started, but he really, with the quality of MIT students, really took it off. He did tremendous things for the field. And certainly deserved to get tenure and he did get tenure because he switched to engineering science. But, then you come along with COSMAT, and Morris Cohen pushing that we're going to have Materials Science and Engineering as opposed to just metallurgy. We need to look broadly at the field and all the classes of materials, although concrete was excluded. I never heard anyone bring up concrete and I think they always said, "Well it's a commodity or something." They didn't think of steel as a commodity, but they knew that plastics was a growing business.

AH : Bernie actually had a feasible argument for this kind of thing, he says that if you have something where very little capital and research goes into it, a cheap material, like concrete, than it's not a topic in Materials Research. It has to be...

TE : Well.

AH : An expensive material, one that you sink stuff into in order...

TE : I have a plot that I've used, actually, I stole it from [Jack Westboro]. It's an internal GE report. And it shows this on a log scale. The log of tons used, [drawing] yeah the log of tons versus the log of price. Ok ?

AH : Of any material ?

TE : Structural materials.

AH : Ok.

TE : Structural materials. And you have diamonds over here, at about a million dollars a ton. It might have been $100,000 a ton back then. And you have stone up here, crushed stone, at like ten to the thirteenth tons, I mean something incredible. You have concrete, it's not tons it's pounds. And you have steel. Ok ? Steel is like ten to the eleventh, I think stone is ten to the thirteenth, and concrete's like ten to the twelfth or something. And it goes all the way down here, and you have, you know, there is a wonderful correlation in this very narrow band, I can get this for you if you want, but it if you look at the...

AH : What time is this ?

TE : This is 1962 that he actually did it, and if you look at iso-market size lines, and they look like this, so this is steeper than the isomarket size. Which means that if it's a, if you can drop the price of the material by a factor of 2, you should increase the usage by a factor of four. Ok ? Based on the slope here. Which means that your market doubles. So if you actually, and I've used this argument a number of times, that we really should be pushing for reducing costs and processing of materials, rather than looking at more elaborate materials that are always going to be boutique materials that no one uses much. In any case, getting back to Flemings, and the COSMAT stuff, basically that's when Flemings started politicking with Morris Cohen that he should do processing-structure-properties. Because in the sixties it had always been the structure of properties. And Flemings started saying, because he was in the processing side of the department, he was one of the only guys ! He was the one arguing that we should add fluid flow, he taught a heat and fluid flow course. He is basically trying to carve out a niche for himself in a department that he didn't quite fit in. Ok ? And he did ! Very effectively. And he convinced a bunch of the rest of the people. Now the people in industry loved it, because they knew processing was where they made their money. So you're right about the fact that industry knew it, but if you look at academia, I think I have to give credit to Mert Flemings, for really being the guy who led the country ; you notice in here actually, he's quoted about as many times as anybody.

AH : We could talk about it then in a similar way to the way we talked about physics sort of seeping in with a time delay, that the market is sort of seeping into the academic world with a time delay.

TE : Yes.

AH : Does that make sense ?

TE : Yes. There's, the problem is the time delay, well there is feedback between the two, and it goes both ways. Ideas and knowledge seep into industry with a time delay. And in fact, this idea that the field is broader than just metals is something that came from academia, and has seeped back into industry with a time delay. Industry now accepts it, but in the seventies and eighties, they were fighting it tooth and nail. They were very upset, and threatening on withdrawing their support. It turns out they were going to withdraw their support because the profitability was going down, ok ? But they used it, and they come in and say, "Well we're not going to support you anymore like we used to, because you're not supporting us like you used to." And so in a sense, the whole broadening of the field to look at other materials was kind of a major thing. Another person you might want to talk to is Harry Gatos.

AH : Yes.

TE : You know Harry ?

AH : Yes, well I don't know him but...

Te : But Harry was really the person who brought electronic materials into the department. And he had been an undergraduate in the department, and I think he worked in mining. I don't remember exactly what he worked in as a student. He went out to Lincoln Lab and he became head of the whole solid-state division within a few years. Of course they were growing semiconductors. Harry became "Mr. Gallium Arsenide," you know, before it was popular. And in the mid-sixties, he was offered a full professorship in the department, and he brought a million dollars worth of equipment, which was a lot of equipment, with him from Lincoln Lab. And basically set up his own little fiefdom, he was another fiefdom, all of the sudden we had a new fiefdom in electronic materials they've never had before. And Gus Whit, who could be an interesting person to interview, to show you what they did to junior faculty, I don't know if you're interested in the internal politics. Gus was a physical chemist, he had been hired to work with [Phil DeBruin]. Phil DeBruin was a Dutchman who was a great man at [froth flotation], which is a way of recovering a good part of ores from the ores. DeBruin was kind of the last man standing in mining. And in 1962, they had a vote on whether to continue mining in the department. And with one dissenting vote, John Elliot, the department decided to drop mining. Well Phil DeBruin was still at MIT, and he became head of the graduate committee and graduate admissions and stuff. Gus Whit had been hired originally to come and work for Phil DeBruin. Gus was a surface chemist, a physical chemist from the University of Innsbruck or somewhere in Austria. And when he got here, he went in to meet with Tom King. 1962 was when John Chipman had stepped down, in '65 and Tom King became the department head, and Tom King called Gus in when he first came to MIT, and Gus thought he was coming over to work and be a gopher for Phil DeBruin in mining engineering, and Gus says, "We no longer have mining engineering in the department, we've eliminated it. You should go over and work with Harry Gatos in semiconductors." Ok ? And Gus says, "What do I do ?" Well, he went over and worked with Harry Gatos in semiconductors. And the two of them from the mid-60s through 1990 were the powerhouse, basically, in electronic materials. Until we finally started hiring some more in the eighties, and then the two of them retired. Well Gus is actually just retiring this year, but Gus really hadn't done anything for the last twelve years in terms of real science or research. But anyway, that's how they brought in electronic materials. They imported Harry Gatos. And that was one of the first electronic materials groups in the country.

AH : How do you see the impact of national politics and funding, lets say DARPA, and the NSF grants ?

TE : DARPA was very important in setting up the Materials Science Centers around the country. That was a big move, there's no question about it, in the early 60's, a tremendous boost to the whole field of Materials Science.

AH : Was there a field before that ?

TE : Well actually, it's not clear that there was, I mean you really have to talk to Morris Cohen or some other people of that genre. I was in elementary school, I was in grade school, or high school or something during that period. But certainly, that was one of the things that switched, helped push it from, helped push the academics from thinking of it as always "metallurgy," because certainly the Materials Science centers were not set up just be metallurgy. The military, you know, knew they needed all types of materials and they wanted to support all types of materials. NSF only inherited it because of the...

AH : Mansfield ?

TE : They inherited it because of Mansfield. And they continued to support it although they do a lot of sabre rattling, but it's still kind of a central thing to to the whole thing. So I think DARPA's deciding to fund the material science centers was or it might be that it was the beginning, but I can't tell you though.

AH : Yes. No it was. Then in your time, what's the, has it shifted...

TE : The funding ?

AH : Boundaries around ? Is it ?

TE : Well...

AH : That must've been...

TE : Yes. It has, I mean it used to be. After Sputnik it was mostly government funding. I mean I remember my old thesis advisor Bob Rose had all kinds of money in the sixties. In fact he used to tell us the story, the joke was "While you're up, get me a grant !" All you had to do was kind of... Well actually, to tell you a little more of the story that I had heard, because of the Manhattan Project, in World War II, you had John Chipman working on a lot of the physical chemistry. He was working on trying to create crucibles for uranium and stuff. There was no material, Uranium is too reactive, and so they were working on the physical chemistry of what they could use for crucibles to melt the stuff. And Morris Cohen was working on, well somehow, I don't remember what he was doing. But there were projects going on for the Manhattan Project. And I remember John Wulff telling the story, he was on the outside, he was one of these processing guys that they looked down on. But he knew uranium was very important, but he didn't know exactly why. And he had been studying trace elements in oils around the world. And he dropped in at a cocktail party and said, "You know there's a lot of uranium in the oils in the Balkans," or something like this, and the next morning there were two secret service agents in his office asking him what he knew about uranium. That type of thing. But anyway, what happened is because of their help on the Manhattan Project, Norton in ceramics, Cohen in physical metallurgy, and I think someone else. There were two or three grants that came from the Atomic Energy Commission that basically just funded these guys for the rest of their careers. I mean the Atomic Energy Commission became the Department of Energy and stuff. And it turns out I remember in the early eighties, Kingery and [Kobel] still had Norton's old grant. That was the last one remaining of this kind of gravy train of funding that you get as the equivalent of one and a half million dollars or two million dollars today. They would just get it for just kind of telling people in Washington, "This is how much money we need next year." It was sort of a reward for what they had done on the Manhattan Project. After Sputnik, it got to be very easy for even junior faculty to get funding. I remember when I started on the faculty in 1976, 25% of all NSF grants got funded. And if you were from a place like MIT, you probably had a 50% to 60% chance, probability of getting a grant funded. Today, or in the mid-nineties, it dropped to like 5% of NSF grants are funded. And if you're from MIT, it probably cuts your odds by half, because the other schools out there. What happened is in the seventies, a bunch of other schools found they couldn't compete on quality of proposals, so they started competing in Congress. And then at NSF, they started competing by sending more of their faculty off to be rotaters.

AH : This is in the seventies ?

TE : This is in the seventies and eighties. And a lot of these people basically just had it in for the schools that have been on these gravy trains, ok ? I mean in the late-eighties we lost the National Magnet Lab to Florida, and that was a pure buyout by the state of Florida. Alright ? And MIT was judged to have the best proposal, but the politics at the NSF were such that they decided they couldn't turn down the money from Florida, plus they wanted to send the message to these elite schools, that they weren't going to continue to just get things just because they had better proposals.

AH : I talked to Dale Corson at Cornell, and he spent half of his life in D.C. He said this is the way it always worked, there's no way you can run a department or a school without taking D.C. seriously.

TE : Well, yes and no, I mean that's one way to do it. And in a sense you could say the guys who worked on the Manhattan Project and made their contacts in D.C. were using their "old boy" connections to get their grants. But that's not what happened to me. Ok ? I was hired on as an assistant professor, I was still working at Bethlehem Steel. I talked to some professors on the phone and they said, "Well you ought to go talk to so and so in Washington." And I called up some of these guys. One of them was Bruce MacDonald at ONR. And Bruce actually was willing to let me come down from Pennsylvania to talk to him before I even started at MIT. And he told me what ONR was interested in. Now Bruce happened to be an old MIT grad, he was one of Morris Cohen's students. And he was in charge of the welding program, and he wanted, you know, and I was a welding engineer at Bethlehem, and that's how I got to know Bruce. I then talked to my old house tutor, who actually was a welding, head of the welding group at Union Carbide. They were doing a project on submerged dark welding of titanium, they didn't see a market for it, but they did have some useful results for the Navy, and they were not going to ask for a renewal. So Dave says, "Well why don't you write to the Navy, maybe they're interested in this." And I did, that was my first contract at ONR. I found out what the Navy was interested in by working connections, and that's why it helps to be at an elite school, because you have some of the connections. Bruce MacDonald was an old MIT person, and so he wanted to help if he could, but Bruce is an honest enough guy that if you didn't write a decent enough proposal he wasn't going to help you. But I found that when Dave Hill told me that, you know, the Navy is interested in this, and we're not interested in pursuing it as a company anymore, why don't you write a proposal ? That was my first proposal, and the first one funded, and since then, I did a good job for the Navy, and I'd serve on committees for them, or I'd spend part of my summer working with their engineers, but not politicking. Ok ? I've continued to be funded by ONR, but I have not had to do politicking. I have been continuously funded since 1977, 25 years by ONR, based on the quality of my work. Ok ? Now at NSF, I wrote a proposal to this guy [Bob Ranig] Bob Ranig was a very ecumenical guy, he was from UPenn. I called him up and said I'd like to come and meet with you, because that's what Tom King and Bob Rose and other people, the faculty of MIT said, he was head of materials science then and Bob says, "You don't need to come see me. Just write me a proposal. Tell me what it is you want to do, how you're going to do it, and if you're successful, so what ?" Ok ? That's been the outline of my proposals ever since. Those three things. I had continuous NSF funding until two years ago. I got kicked out for what I consider one of my better proposals because they kicked me over to the engineering side, not the materials side, where they do these panel reviews. And those things are vicious. You have a bunch of people from these other third-rate schools who come in and they don't even know what they're talking about and they say, "Oh this one's from Stanford, this one's from MIT, we're going to kill it because we hate these guys. They always get the money and we don't." Ok ? It's a terrible system, and I lost my NSF because of that, but I had continuous funding from NSF. Now that's partly, not necessarily because of the quality of my work, in terms of NSF peer review, but it was because when Bob Ranig, and when he left, Bruce MacDonald went over there. They knew I did engineering applied work, but did good science behind it, I mean I had good fundamental science behind it. And they liked my type of work. Bob Ranig told me once when I was a young un-tenured professor, I said, "Bob, I understand you had, you wanted, you had a lot of proposals on Fermi surfaces, and that's the type of work you do." And he said, "Tom, last year I had 33 proposals on Fermi surfaces, and I funded one of them. I had one proposal on welding, yours, and I funded it." Ok ? So there were all these materials scientists trying to be pseudo-physicists, and Bob didn't care about that. So it was really Bob Ranig and then Bruce MacDonald who liked the quality of my work. I never even walked through NSF until the early 1990's. I never walked through the door of that building. And so I've had people tell me the same thing you were told at Cornell, and I say, I've said, "Not true." Ok ? The department of energy, I ended up getting in, there was a committee that looked at what materials science the DOE should be funding, and [Kent Mullen] who was a faculty member here, served on that committee, he might have even been chair of it. He was kind of a golden boy that had gotten in with the DOE group from the old AEC stuff. During the Kingery and Kobel ceramics stuff. So he was in tight with those people because of some of the "old boy" connections, and Kent comes back and he tells me, "Oh we said welding was a high priority item. So it'd be good to send the proposal in to DOE basic energy sciences. So I got together with [Joe Sekelly], and we sent one in and we got it funded. Now that was rocky for, well they funded us for six years and then they dropped us the year we won an award for our paper. Which I always thought was sort of interesting. And then a year later, there was another report at DOE, the Packard committee report, which basically says the national labs and the universities should get together and do joint research. [Ken Hansen] in Nuclear Engineering over here was on the board of Idaho National Lab. So they got together and they said, "Oh, well we ought to do some joint MIT/Idaho National lab thing." And they put together this big program. Dave Parks was part of it, and I was part of it, and all of the sudden it turned out to become eventually, for a while, my biggest contract for DOE. That stayed for about ten or twelve years, and finally I got refunded separate of that program, and I'm still funded by that program. I've had a six month hiatus one time, just because of their funding cycle. But I still never have walked into the DOE, Gaithersburg building. Ok ? So you can say this but I mean yeah, I've worked closely with ONR, but they took a plier on me before, I did walk in that building and talk to Bruce MacDonald, because he's willing to take the time to talk to me, but in terms of all this other politicking ? Now since then I now have another DOE contract that came because some guy from the University of Alaska came six or seven years ago and said, "What can MIT do to help the University of Alaska ?" And so we set up this thing, and we actually have been going through Senator Stephens, who's head of the Senate Appropriations Committee and is from Alaska. And we've been able to get some funding, which now is my biggest contract, when it starts up again, and that's pure pork ! Ok ? If you want to call it that.

AH : You can call it whatever you want.

TE : But that basically is pork. It's pork going to the University of Alaska and then they ship some to us. So it's not as if I've never played that game, but I didn't start playing it until like 1996, and I've been here for two decades before I started playing the game. So yes, there are the "old boy" connections in Washington, and those are probably the most common. But is it absolutely necessary ? No. I guarantee that it's not absolutely necessary.

AH : I mean Dale Corson went up to a very senior position within the university administration, probably in that kind of position it's more important.

TE : And frankly, MIT has not been playing that as well as they used to. Our senior guys, well Chuck Vest is down there, but you look at our Provost and other people... Nam Suh is down as Director of Engineering at NSF, but I can't think of anything, and that was more than ten years ago. I can't think of anybody else. We've had Millie Dresselhaus who was number two at the Department of Energy, she was head of the energy sciences, but she only did it for a year. [Ernie Monitz] was down there in physics and energy sciences, but I can't think of anybody else at NSF. And we haven't really done rotations through ONR, other universities have done that, but MIT hasn't, MIT faculty haven't been willing to do that. It's not lucrative enough.

AH : Hasn't there been a shift in funding in some way, government funding ? Has it become more and more private ?

TE : Well, and the reason for that is there used to be a 50% chance of getting an ONR, or NSF contract, if you sent it in from MIT, but now you have a 2% chance. Ok, less than average. So what happens ? You go for industrial funding. Well, there's been more and more industrial funding as industry has dropped off its own in-house labs, so there's been more funding. Actually, I've always said, "Well if industry decides to go fund people, MIT will do just fine, because they're going to look for the best places. And we get the best students." So they're going to come and fund us and we have more industrial funding than anybody else by a factor of two. And that's true. We no longer can get the government funding like we used to, because we don't have the inside tracks, and in fact being from MIT is now more of a detriment than a plus in many cases. Sometimes it's political, but sometimes it is merit based. So there's not...I'm going to have to go here and catch my flight.

AH : How much time do we have left ?

TE : Another 5 minutes.

AH : Let's just make sure I ask this question. You said before that for religious reasons you couldn't use the word proud, were you being flippant or ?

TE : No. I'm actually a Mormon, ok ? I'm a Latter Day Saint. And pride is a sin. Now most Mormons don't do this, but I actually have tried to expunge the word proud from my vocabulary. Now actually when I used it, I used it in terms of other people being proud, but in terms of saying "I'm proud," I actually have done pretty well, I'll now say I'm pleased. I don't say I'm proud of my children, I am pleased that my children have done well or whatever. It's just more of a psychological thing than anything else. But yeah, it actually, it is something I've done. It's not typical Mormonism but it is more of a philosophy that you're not supposed to be proud and arrogant.

AH : The MRS, the Materials Research Society, is a different kettle of fish from the MIT department.

TE : Yeah, but Harry Gatos was the founder.

AH : Harry Gatos was one of the big guys, but in my opinion it would be Rustum Roy...

TE : Well there were a few others but..

AH : Rustum Roy always claims to be the...

TE : There's an arrogant guy. Rusty's fine, but Rusty claims lots of things that aren't necessarily true. Rusty was one of, he got it together, but it was really Harry Gatos', if you just look at what they were doing originally, it was Harry Gatos as the brainchild. He was the loner, he was this electronic materials person among all these other people who didn't even know what electronic materials were. He knew the people at Bell Labs who were decent physicists and stuff, and he decided that he ought to do something. And he got a few people, like Rusty and a few others, but it was the group of them that did it, but the guy who really was the brainchild behind it was Harry.

AH : Were you a member of the MRS when they started ?

TE : No. Because they were a bunch of scientists, physicists, and I'm on the far engineering side of it. I didn't join it for years.

AH : So in the 80s you also didn't join them ? Did you go to their meetings ?

TE : I've never been registered at one of their meetings, I've been to some of them when they're over here. I've been to some of them when I've been asked to talk, but I, usually it's the Boston meeting, and I just kind of slip in without registering, that way I don't have to pay the registration fee. I am a member now, and I think I joined in the late-80s just because they were growing and it was important to kind of read the things, and I edited one of their MRS bulletin things in the early eighties. But it's the same type of thing. I've never been part of the Center for Materials Science and Engineering, I have never put in a proposal to them. Why ? Because I've been able to get plenty of funding on my own, but they gave it out in smaller lumps, and it was just a bigger pain. I mean I can get better funding, and again, I'm on the far engineering side, they were trying to sell to the NSF that they were this wonderful Materials Science group, as half baked physicists, right ? And I didn't fit that model, ok ? Everybody thinks of me as the industrial guy, but it turns out it's sort of funny to me because I've had relatively little industrial funding. Ok ? I've had mostly basic energy sciences, NSF, and ONR. Ok ? And I've always basically had more fundamental science funding than all these other guys who claimed that they were the fundamental scientists.

AH : But from my understanding of the MRS, it is that it's focus is actually much more towards the application end and the engineering side, but certainly...

TE : Well, from a physicist's point of view, that's true. From a materials science view they're into fundamental science.

AH : Is that right ?

TE : Well yeah, they're kind of middle of the spectrum. Ok ? The physicists look at them as more applications oriented, but the materials scientists look at them as, oh, they're more fundamental. Because that's what, I mean there's a lot of support from industry for MRS, but, but even so, I think it depends on whether you're a physicist or whether you're really a materials scientist. You know, the spectrum I talked about before, where you have a physicist here.

AH : Sort of the pure, applied...

TE : Pure applied, and you have engineering all the way over here, well Tom Eagar is over there, but The materials science is right here in the middle. Ok ? The physicists look at materials science's applications. Materials Science and Engineering is really here, and this is Materials Engineering, and this is Materials Science.

AH : So the MRS is not really your place.

TE : No. The MRS is primarily, well, actually, I probably ought to, they're probably more central than Materials Science and Engineering.

AH : I should have asked you before with the Mormon question. Do you have any, do you do your science differently because you're Mormon ?

TE : No.

AH : It has no connection ? Two different worlds.

TE : I think I do it more objectively. Because, well more honestly, and I don't know if that's necessarily because I'm a Mormon, although it doesn't hurt. But I've always had a problem with these people that say, "Oh, well Buckytubes are wonderful." Ok, I've written all kinds of articles about people running off on these bandwagons of materials. Back in the 80's when, again, when people said ceramics were the future of everything, just like George doesn't believe it because of the fracture toughness, I never believed it, and I used to write articles that said this is, you know, that the ceramists don't know what they are talking about. They had never discovered fracture toughness. And that actually happens to deal more with my honesty, ok ? Now, and the other thing I think is I manage my lab quite differently. The reason I've got nine best paper awards, whereas most of my colleagues have zip, ok ? And I have lots of other types of honors and stuff, is not because I get along well with my faculty colleagues. I mean my department head now, Subra Suresh, is a politicker. I mean he's the fellow of this society, a fellow of that society, a fellow of that society. I think he has one best paper award. Ok ? He's actually a very distinguished person and very well thought of, but I have nine best paper awards, and he has one. I'm a honary member or a fellow of two societies, and he's an honorary member of seven or eight ! Ok ? He goes to the meetings and schmoozes. I don't go to any of the meetings and schmooze, because I'm not interested in that. I lead my department, I lead my research group, I don't manage it. And there's a distinct difference, and a lot of that comes from my leadership and management training as a member of the Mormon Church. Ok ? I'm a Bishop for the church right now, as far as that goes, but... I'm here to educate the students to learn to be professionals. SO I have to define a problem, and let them flounder for six months, or sometimes more. And if they flounder completely, I have to be able, you know, in a few weeks, to completely repair the damage and get them a thesis and get them out. Which has occured a couple of times. But in general, I'm there to give them a lot of flexibility. I provide the resources, the research money, and the resources, and I critique what they do, but I actually let them do it. And I actually sometimes, with some people I end up forcing them to work on one of their weaknesses and other people I let them work on their strengths, and it really depends on where I think they're going to grow and develop the most. And I think actually that is part of my religious upbringing. It is that the important thing is developing the person, and I don't really care about the research results. And I've actually, a few say, "Oh well," and then other faculty say "Well I proposed this and then they have a timeline of what they're going to do." And that's what they try to do. Once I get the money, other than the general topic area, I don't care what I do. I let the student go off and do whatever they want. And the thing is, when you have bright students at MIT, that's the way to manage them. You lead them. You don't manage them. And they will produce much better things than I could ever produce. And they have ! And that's why, you know, I have these nine best paper awards. Because they are bright students, and they actually, I've had a number of them come in and they're used to being told what to do. I mean John Elliot used to bring students in once a week and he would go over their lab notebook line by line. He would tell them how to clip the ends of the thermocouples, ok ? If a student doesn't come see me for six months, I might say, you know, ask my secretary to get an appointment, just tell them I want to see them and find out how they're doing. But usually I will walk through the lab or a luncheon seminar or something, and we'll talk. But I'll let them go for six months and I'll never bug them about what they doing. They know what their problem is, I've told them, you know, and they have to get back to me. And at first, some of them figure this out very quickly by talking to their older colleagues. Some of them don't learn it for six months, but after a while, all of the sudden, they learn it, and lo and behold, then they catch fire, because they realize the thesis isn't going to get done if they wait for me to do it. And I've had a number of them, I take them to lunch when they finish their doctorate, and one on one they ask me about things, and I've had a number of them say, "You ought to push the students harder." And I said, "You didn't feel a lot of pressure to finish your thesis ?" And they said, "Oh I felt a lot of pressure." I said, "But it was self-motivated." "Yeah. Because you weren't pushing me." I said, "Yeah, well don't you think you actually felt more pressure than if I had been pushing you ?" "Yeah !" Ok ? "And so you learned to do it yourself, right ?" And that actually comes from my religious background of the progression of the individual is more important than the task.

Fin de l'enregistrement

haut de page

accueil du site

Entretien avec Thomas Eagar, par George Smith (Acting Director of the Dibner Institute) et Arne Hessenbruch, 6 mai 2002

Lieu : Dibner Institute, MIT, USA.

Support : enregistrement sur cassette

Transcription : Arne Hessenbruch

[George Smith (Acting Director of the Dibner Institute)].

Édition en ligne : Sophie Jourdin.

BARBOUX Philippe, 2000-12-12

Sophie Jourdin — 2011-09-19T08:33:30Z

Philippe Barboux est professeur au Laboratoire de physique de la matière condensée, à l'Ecole Polytechnique – Palaiseau (France).

Pour citer l'entretien :

« Entretien avec Philippe Barboux », par Bernadette Bensaude-Vincent, 12 décembre 2000, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article46.

PHILIPPE BARBOUX (PB) : J'ai fait une thèse chez Collongues après avoir commencé la biologie à Polytechnique. A l'époque, en 1981, Bernard Sapoval voulait un rapprochement avec la chimie du solide, aussi m'a-t-il envoyé voir Collongues. C'était un personnage enthousiasmant. Je me rappelle cette visite dans son bureau à l'Ecole de chimie, en plein mois de mai avec deux arbres en fleurs derrière la fenêtre. Après une heure et demie de baratin sur les batteries, il m'avait convaincu, je me suis inscrit en thèse sous sa direction.
Il m'avait mis sur les gels conducteurs ioniques, dans le groupe de Livage. On y faisait la découverte de propriétés curieuses, amusantes. On étudiait la mobilité protonique à température ambiante dans l'eau.

BERNADETTE BENSAUDE-VINCENT (BBV) : Y-avait-il un enjeu industriel ?

PB : A l'époque, ils n'avaient pas – et moi non plus – réalisé tout le potentiel industriel. C'était novateur de chercher les applications de ces solides. Collongues avait, lui, une notion de ces applications mais ce n'était pas primordial dans son esprit. Dans le labo Collongues, on préparait des oxydes à hautes températures. Les Américains, en revanche, vendaient des applications même s'ils faisaient le même travail que nous.
J'ai fait deux thèses : d'abord, une thèse de troisième cycle, en 1984, qui m'a permis d'entrer au CNRS. Puis, comme la thèse d'Etat avait disparu j'ai fait une thèse d'université : les deux sur la mobilité des ions dans les systèmes poreux et les matériaux cristallins.
Après la thèse, j'ai voulu travailler avec Jean-Marie Tarascon sur les batteries au lithium mais on est passé aux supra-conducteurs en 1987.

BBV : Comment en êtes-vous venu aux piles à combustibles ?

PB : Aujourd'hui, je reviens à mon sujet de thèse. Les piles à combustible, c'est un sujet enthousiasmant pour recruter des étudiants en stage ou en thèse. J'ai commencé en septembre 99. La thématique est la diffusion dans les membranes. On travaille le nafion qui rentre dans les piles à combustible. C'est un polymère qui se déforme quand on applique une tension dessus. On mesure les déplacements du nafion. On a un projet muscle artificiel avec un étudiant qui fait de la robotique.

BBV : Avez-vous des liens avec l'industrie sur ce sujet ?

PB : Nous travaillons dans le cadre du CNRS, sans contrat industriel, sauf pour les thèses d'étudiants (thèse Cifre-Saint-Gobain). On a cependant des consultations ponctuelles : par exemple H2Tech une petite entreprise locale nous demande conseil mais juste au moment d'écrire leurs rapports. L'effort pour établir un contrat européen fut un échec. Renault nous a dit prenez des brevets d'abord après on verra.

BBV : Comment expliquer l'abandon du projet pile à combustible dans les années 80 après les efforts déployés dans les années 70 ?

PB : Dans les années 70, la recherche était sous-tendue par la volonté de faire des économies d'énergie et d'argent à cause de la crise pétrolière. De plus, à cette époque l'industrie française était en tête de la technologie sodium-soufre et alumine-bêta avec CGE. Sur la pile à combustible à base de zircone, Mme Antony a travaillé à Orléans dans les années 70.
Dans les années 90 se produit une remobilisation sur le thème du stockage d'énergie aux USA par suite de plusieurs accidents : d'une part, le tremblement de terre de San Francisco a révélé la non-fiabilité de la source d'énergie de secours (les batteries au plomb dans les hôpitaux n'ont pas marché). Et surtout plusieurs accidents d'explosion avec des batteries de portables ont focalisé l'attention sur la sécurité. Moli-Energy, où travaillait Tarascon, a fait faillite par suite d'une explosion de certains de leurs téléphones. Donc la recherche sur le stockage d'énergie est orientée vers deux objectifs : fiabilité et sécurité.
Pour augmenter la sécurité des batteries au lithium il y a deux voies :

la voie Armand, qui consiste à utiliser un électrolyte solide à la place de l'éther. Li-PEO avec un sulfure, par exemple. On joue sur la passivation et on ralentit la formation des dendrites de lithium métallique qui sont extrêmement dangereuses. Mais on perd en puissance.
la voie japonaise : ne pas avoir de lithium métallique mais seulement du lithium –ion grâce à un graphite d'intercalation à l'anode : Li-C6. C'est la batterie rocking-chair. Le problème c'est qu'on augment le poids et qu'on diminue la puissance.

BBV : Envisage-t-on des piles à combustibles pour les portables ?

PB : Oui, c'est récent depuis un an et demi on travaille sur des mini-piles à combustibles. Il y a des brevets américains sur des catalyseurs basse température avec du méthanol comme source d'hydrogène. On peut espérer un facteur 2. Beaucoup de gens travaillent dessus actuellement. L'idée est d'avoir des feutrines imbibées de méthanol qu'on recharge comme les briquets d'antan.

BBV : Quelles sont les chances de la pile à combustible pour les véhicules électriques par comparaison avec les batteries électriques ?

PB : La batterie Lithium-ion est envisageable. Problèmes de solidité et de résistance. La batterie polymère est envisageable mais le problème est qu'il faut plus que de l'énergie, de la puissance.
Actuellement il y a des recherches sur la pile à combustible à Westinghouse (zircone, haute-température) et en France à Grenoble. Le problème avec la zircone c'est qu'elle réagit avec l'oxyde de la cathode. Les électrodes interdiffusent l'une dans l'autre, d'où vieillissement rapide.

BBV : Quelle est la situation de la recherche en conduction ionique en France ?

PB : Dans les années 90, il n'y avait plus de recherche en conducteurs ioniques en France. En fait, on était tourné vers la recherche fondamentale. On était absent de la concurrence internationale au moment où les Japonais ont occupé le terrain des batteries qui s'exportent en même temps que leurs appareils.

Fin de l'enregistrement

haut de page

accueil du site

Entretien avec Philippe Barboux, par Bernadette Bensaude-Vincent, 12 décembre 2000

Lieu : Laboratoire de physique de la matière condensée, Ecole Polytechnique- Palaiseau, France.

Support : enregistrement sur cassette.

Transcription : Bernadette Bensaude-Vincent.

Edition en ligne : Sophie Jourdin.

COLOMBAN Philippe, 2003-02-18

Sophie Jourdin — 2011-09-19T08:07:32Z

Philippe Colomban, born in 1952, was trained as an engineer at the Ecole Nationale Supérieure de Céramiques Industrielles (at Sèvres). He started his research career in an industrial laboratory at Thomson-CSF where he prepared PLZT optically clear ceramics by sol-gel routes. Then he moved to a CNRS (Centre national de recherche scientifique) laboratory directed by Robert Collongues, where he studied proton conduction. He became an expert in the synthesis of pure monocrystals of beta-alumina. Later he moved to the ONERA (Office National d'Etudes et de Recherches Aérospatiales, The French Etablishment for Aerospace and Aeronautics).

Pour citer l'entretien :

« Entretien avec Philippe Colomban », par Bernadette Bensaude-Vincent, 18 février 2003, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article57.

BERNADETTE BENSAUDE-VINCENT (BBV) : D'abord je voudrais vous remercier d'avoir spontanément proposé de contribuer à notre site sur l'histoire des matériaux. Ce genre de feed-back est très enrichissant. Afin de préciser votre point-de-vue, pourriez vous rappeler un peu votre parcours de chercheur ?

PHILIPPE COLOMBAN (PhC) : Enfant, je rêvais d'être géologue mais comme l'Ecole de Nancy offrait peu de débouchés dans les années 1970, j'ai opté pour l'Ecole de Céramique. La céramique est assez proche de la géologie, en effet, dans la mesure où elle traite de roches synthétiques et d'exploitation des carrières. A l'Ecole de céramique (à Sèvres) j'ai eu comme enseignant Jean-Pierre Boilot alors jeune assistant et Mme A.M. Antony qui travaillait sur la zircone en tant que céramique. Elle connaissait bien Collongues qui, lui, travaillait à l'origine sur les oxydes fer et s'était attaqué aux cristaux de zircone.

BBV : A chacun son territoire, en quelque sorte ?

PhC : Tout à fait. C'est une caractéristique de la chimie française dans les années 1950-70. Les universitaires se répartissent les domaines d'après les chapitres du PASCAL (l'encyclopédie en français de Chimie Inorganique, le pendant du GMELIN allemand) : les oxydes de fer chez Chaudron puis chez ses élèves à Vitry, les nitrures à Limoges, la zircone à Orléans, les verres et métaux de transition pour Hagenmuller à Nantes (je crois puis Bordeaux, il faudrait interroger Paul Hagenmuller). Chaque élément est pris par les maîtres d'un lieu et ses " descendants ".

BBV : Comment êtes vous arrivé au laboratoire de Collongues ?

PhC : C'est Mme A.M. Antony qui m'a envoyé chez Collongues. Il m'a confié la conduction protonique. Le choix du sujet répondait à une incitation industrielle. Il faut dire que le laboratoire Collongues avait de gros moyens pour la synthèse de cristaux. Collongues était très ouvert, très souple et savait établir des relations de confiance avec les industriels. Ce n'étaient pas toujours des liens formalisés, par écrit, plutôt des accords qui formaient un réseau de contre-parties. Ce genre de liens est possible à Paris car on circule d'un lieu à l'autre, on a une oreille partout. Alors que les laboratoires de provinces, comme celui de Hagenmuller, ont développé des liens beaucoup plus formels, avec des rivalités plus marquées entre des centres de recherche qui veulent avoir le monopole d'un sujet. A cet égard, Livage est plutôt du style Hagenmuller, à défendre son pied carré. Collongues ne faisait jamais de rétention d'information, il était vraiment un meneur d'équipe.
Pour revenir à la conduction protonique Collongues avait reçu de l'argent de l'Air Liquide à la suite de la parution d'un article par Richard Brook alors à Leeds (qui par la suite est allé dirigé le département céramique du Max Planck Institut avant de devenir directeur du département céramiques à Oxford et de l'EPSRC, l'équivalent anglais du CNRS) et J. S. Lundsgaard, un danois qui a fait son PhD chez Brook avant de travailler à Odensee puis de monter une petite société (J.S. Lundsgaard, R. Brook, J. Materials Science 9 (1976) 1061)

BBV : Quel était l'intérêt industriel de la conduction protonique en 1975 ?

PhC : Elle était alors envisagée comme une alternative énergétique. On était après le premier choc pétrolier et les énergies propres étaient désirées. C'est l'époque de la mise au point du Nafion© par Dupont pour les piles à combustibles du programme Gemini et l'on voulait des matériaux susceptibles de fonctionner à plus haute température pour éviter les catalyseurs de platine. Pour l'Air Liquide l'intérêt était de pouvoir réaliser des capteurs de teneur en hydrogène stables, rapides pouvant fonctionner à une certaine température. Avec la Thonson-CSF (G. Velasco et M. Croset) je developpais plus tard de tels capteurs " microioniques ". Ce fut les premières réalisations d'un équivalent ionique de la microélectronique (La Recherche, 148 octobre 1983, 1292-1296). En Europe nous étions deux à travailler sur la conduction protonique, moi (!) et le laboratoire d'Odensee au Danemark dirigé par Johs Jensen, le " patron " de J. S. Lundsgaard. Avec Jensen j'organisais en 1981 un colloque à l'Ecole Polytechnique où je venais d'arriver pour monter une équipe de Chimie du solide formellement avec J. P. Boilot, mais qui était encore pour quelques années surtout à Limoges où il avait été nommé professeur dans la fournée du déménagement de l'Ecole de Céramique. Ce colloque était financé par une fondation danoise et l'Ambassade de France. Il fut le premier d'une série qui après internationalisation continue encore. Johs Jensen fut vraiment la cheville ouvrière du développement des travaux sur les piles à combustibles " propres " en Europe.

BBV : En quoi consistait essentiellement votre travail dans le laboratoire Collongues ?

PhC : J'y faisais essentiellement de la synthèse et de la diffraction des RX, les analyses de diffusion diffuse de RX étaient faites à Orsay avec G. Collin et J. P. Boilot, les études Raman et IR à Thiais avec G. Lucazeau et la diffusion de neutron à l'Institut Laüe-Langevin qui venait d'ouvrir avec A. Dianoux. Faire des cristaux de zircone, c'est simple. Pour fondre l'oxyde de zirconium à 2600°C, on couple avec des copeaux de zirconium la poudre : on met l'ensemble dans un creuset, lui-même dans un suceptor qui fournit le champ électromagnétique (MHz). Les copeaux de zirconium sont portés à haute température et ils s'oxydent avec l'air et donne une bulle de liquide qui fait fondre la poudre qui se trouve autour. Pour faire des cristaux d'alumine-bêta c'est plus compliqué car l'aluminium est trop exothermique. On est obligé de chauffer avec un morceau de graphite mais le graphite se met en position de couplage minimum sous l'effet du champ électromagnétique, et il ne chauffe pas. Aussi faut-il le maintenir avec une baguette d'alumine, avec le nez à 15 cm au dessus de quelque chose qui est à 2000°C. Une fois sur deux cela explose. On portait des grands masques comme les sidérurgistes qui ouvraient les poches d'acier (Je pense que c'est un apport de Collongues qui connaissait bien le milieu en tant que responsable de la Société des Hautes Températures et Réfractaires). On arrivait à fondre pendant une heure, à stabiliser et faire croître des cristaux. Cela c'est la technique " traditionnelle " française pour faire l'alumine-bêta, celle qui a été mise au point par Y Lecars. Les américains d'Oak Ridge, de Ford disposaient de gros creusets en iridium ce qui permettait un travail plus facile.
Par rapport à Y Lecars et le thésard suivant Jacques Antoine ce que j'ai apporté c'est le flux à haute-température. La base pour obtenir la phase souhaitée c'est la température. Le diagramme de phase, pour nous, céramistes, c'est le B.A.BA. Il donne le chemin, qui permet d'optimiser la température la plus basse pour obtenir une phase donnée. On ne part pas de la composition à obtenir pour faire une synthèse, on se " promène " dans le diagramme de phase. La technique pour faire l'alumine-bêta riche et l'alumine beta '' (à 1.66) c'est faire un flux à 2000°C avec NaAlO2 qui lui peut être attaqué chimiquement (par HCl) pour récupérer les cristaux d'alumine-bêta riche ou d'alumine béta''. C'est donc un savoir de céramiste qui utilise la synthèse cristalline. C'est grâce à la formation de l'Ecole de Céramique qui était encore restée une école technique plus que scientifique jusque dans les années 1950. Je dois être un des derniers à avoir recueilli l'héritage de millénaires. On avait encore un vieux professeur C. A. Jouenne qui avait été formé avant la guerre 14 dans la tradition ancestrale. On apprenait à " manger les argiles " pour reconnaître le taux de matières humiques, les teneurs en calcium, sodium, en sable, à goûter les céramiques pour mesurer les porosités, etc. On apprenait à reconnaître les fonctions organiques au nez. La céramique, c'est l'alchimie d'autrefois. Elle se perd.
J'ai quitté la synthèse dans les années 1992-94 quand je suis revenu de l'ONERA parce qu'il n'y avait plus d'argent. La synthèse cela coûte cher et il faut deux ou trois ans pour faire un produit. Et en plus ce n'est pas très valorisé au CNRS. Au CNRS (et à l'université) les chimistes du solide ne font presque plus de synthèse, ils ne font plus vraiment leur premier métier. Ils font le travail des physiciens qui eux repassent après pour " améliorer " les modélisations des chimistes. Il est vrai que les composés d'aujourd'hui sont " compliqués " à faire et à comprendre pour ceux qui n'ont pas une triple culture générale : de chimie minérale et organique/polymères et de physique. L'ONERA jusqu'aux années 90 permettait de faire de la " belle " synthèse de matériaux ayant des finalités militaires. Ceci à pris fin vers 90-92 avec la chute puis l'effondrement des crédits -et des motivations, le bottom-up- de recherche militaire et les bouleversements des structures capitalistiques et industrielles de l'armement.

BBV : Quand et pourquoi êtes vous allé à l'ONERA ?

PhC : J'y suis allé en 1989. Il n'y avait plus d'argent à Polytechnique. La mode avait tourné : les matériaux n'étaient plus privilégiés, la biologie intéressait davantage. Moi je voulais faire des vrais matériaux, pas de la chimie en flacon. J'ai regardé un peu autour de moi. A l'ONERA, ils cherchaient quelqu'un pour redynamiser les matériaux non-métalliques, l'ancien responsable étant parti pour la Société Aérospatiale. L'ONERA fonctionnait bien : ils faisaient de la recherche amont, bien financée par l'armée et ils allaient assez loin en développement. Il y avait une grande mobilité car souvent les équipes partaient dans l'industrie avec leur projet quand il passait en phase industrielle. J'y ai développé l'usage du sol-gel et des précurseurs polymériques pour réaliser des composites à matrice céramiques thermostables (à fibres C et SiC) et aussi les premiers composites tout-oxide et à gradient de propriétés pour l'absorption micro-onde (pour rendre les missiles invisibles au radar). Avec J. C. Badot on était les premiers à développer la spectrométrie d'impédance complexe pour comprendre la mobilité des ions dans des superconducteurs ioniques en l'occurrence protoniques. On obtenait des résultats comparables à ceux que l'on pouvait extraire de la RMN ou de la diffusion neutronique. Ceci me donnait le savoir-faire et les outils conceptuels pour aider à lancer à l'ONERA l'étude des matériaux absorbants les microondes.

BBV : En quoi consistaient vos travaux sur le sol-gel ?

PhC : Le premier article sur le sol-gel " français " je l'ai écris en 1974 et il est paru en 1975. Quand j'étais à la Thomson avec Monsieur Hildebrand, un chimiste remarquable rescapé du camp de Penemund (les V2 de Von Braun !) on m'a fait travailler sur un projet de lunettes pour pilotes des Mirages de la Force de frappe nucléaire. Il s'agissait d'avoir une obturation d'une fraction de seconde pour éviter l'aveuglement par le flash de la bombe. Les Américains avaient mis cela au point aux Laboratoires Sandia (Albuquerque) et le gardaient secret ; mais des renseignements avaient été " récupérés". La publication de la première utilisation pensée, voulue, du sol-gel concerne un mélange de titano-zirconate de plomb et de lanthane le PLZT (par G.H. Haertling, C.E. Land, G.S. Snow). Les propriétés ferro-électriques permettent de faire l'obturateur : on applique un champ électrique entre deux polariseurs, la lumière qui a été polarisée ne peut pas passer et cela se ferme en moins d'une milli-seconde. Pour faire cela, il faut une céramique transparente diélectrique avec des propriétés ferro-électriques particulières. Il faut un rapport particulier de zirconium et de titane mélangés intimement avec une homogénéité à l'échelle quasi-atomique pour que la transparence soit parfaite afin de ne pas gêner la vue du pilote, déjà soumis aux fortes accélérations (plusieurs g). Sandia, un labo quasi-militaire dans le Nouveau-Mexique, a fait le mélange à partir du liquide (la fabrication a été je crois reprise par Motorola pour les mémoires optiques). Mais la voie liquide inorganique ne donnant pas satisfaction ils ont pris des précurseurs alcolates (alkoxides) qui, en plus, ne coûtaient pas cher à l'époque. C'étaient des intermédiaires pour préparer des catalyseurs pour la grande industrie des polymères ou pour fabriquer certains alcools. On les vendait par bidon d'une quinzaine de gallons pour le même prix qu'aujourd'hui la bouteille de 75cl (environ 500F) et pour une qualité souvent supérieure.
Bref, à la Thomson on a fabriqué des obturateurs pour une cinquantaine de pilotes de chasse, puis quand les crédits militaires ont chuté, la Thomson a abandonné le projet et c'est le CEA-LETI-Crismatec (je crois Laboratoire d'Etudes des Techniques Electroniques) qui l'a poursuivi.

BBV : Y-a-t-il eu des applications civiles de ces travaux ?

PhC : Des mémoires optiques, la télévision Vidicon et des DVD ont été étudiés dans les années 1980 par Thomson-CSF. On stocke presque à l'échelle atomique du dipôle ferro-électrique. A la Thomson j'avais mis au point une des techniques de Sandia qui permettait d'obtenir des céramiques PLZT transparentes sans utiliser le frittage sous charge. Cela diminuait le coût de fabrication, étape indispensable pour les applications civiles. Ce type de mémoire reste à l'étude pour ses hautes capacités et sa permanence dans le temps. L'effacement est par-contre difficile. Pour ma part, j'ai utilisé le sol-gel pour faire l'alumine-bêta au potassium, qui frittait mal (Material Research Bulletin, 15 (1980) 1817-27). Cela permet d'avoir des poudres ultrafines qu'on peut fritter à plus basse température et d'obtenir un matériau avec moins de porosité, ce qui est indispensable pour faire des mesures. J'ai ensuite développé ce thème sol-gel à Polytechnique, en particulier pour les NASICON, l'alumine, la mullite, etc. On faisait de la mesure de conductivité à impédance complexe, méthode mise au point par les électro-chimistes. Lorsque j'ai développé cela chez Collongues, puis à Polytechnique pour les NASICON, c'était très nouveau pour les solides. Il faut dire que la conductivité des superconducteurs ioniques est égale à celle des acides et donc la transposition était facile.

BBV : Comment décririez-vous la chimie des sol-gel ?

PhC : Le sol-gel existe dans la nature (tout existe dans la nature !), ma formation de géologue acquise comme hobby d'adolescent m'a beaucoup servie) ; l'argile est un matériau nanométrique que l'on met en œuvre par sol-gel. Les céramiques traditionnelles sont des sol-gel, toutes les propriétés de plasticité, de rhéologie, de réactivité,… en découlent. Et il y a une abondante littérature que les chimistes ignorent ou veulent ignorer pour présenter leurs travaux comme des nouveautés. Il s'agit d'une littérature des années 30 à 50 - Norton, Jouenne etc. -. Littérature en allemand, en français mais peu en anglais. Livage a voulu présenter le sol-gel comme quelque chose de nouveau. Ma position à moi c'est que le sol-gel est la transposition de la technologie céramique traditionnelle à de nouvelles compositions par une étape qui est la synthèse chimique d'objets nanomètriques, comme les particules d'argile, où comme la proportion d'atomes à ou près de la surface est dominante développent des propriétés analogues permettant une mise en œuvre sol-gel.
La chimie des sol-gels a démarré à l'époque où on découvrait que, à partir de précurseurs organiques, on pouvait faire de la chimie inorganique. A mon avis elle se situe au confluent de quatre courants :
La céramique traditionnelle ; Sandia, le laboratoire américain avec J. Haertling qui a aussi inventé le Rainbow©, (l'usage de la piézoélectricité marié à un métal ou un polymère pour faire des actuateurs complexes comme battre les ailes de drones ou autre) ; Rustum Roy, de Penn State qui a fait de la chimie des silicates dans les années 50 ; et enfin Joe Mazdiyasni de USAF-Base et B.E. Yoldas, un Américain qui a travaillé je crois aussi avec Larry Hench, l'inventeur des applications en biologie du sol-gel il y plus de vingt ans. Des verriers (comme Dislich et la Société Schott dans les années 40-50, les japonais S. Sakka et K. Kamiya, plus tard) avaient brevetés et étudiés l'hydrolyse de la silice, mais sans sentir de mon point de vue la richesse du procédé.

BBV : Quand et pourquoi êtes vous revenu au CNRS ?

PhC : Pour deux raisons : la première j'aime changer, travaillant avec une petite équipe j'essaye de prendre les sujets " en avance " et de glisser vers d'autres quand ils deviennent " à la mode " et que les gros labo monolithique se mettent dessus. La seconde, en 1990 l'ONERA comptait plus de 2200 personnes, aujourd'hui cela doit être 1600. Les crédits - et donc les perspectives - commençaient à chuter : plus de grands projets où l'on peut partir de l'amont pour identifier des verrous " conceptuels " ou de synthèse, les résoudre et ensuite aider au développement. Je suis revenu au laboratoire où 15 ans plutôt j'avais appris la spectroscopie de vibration pour y développer la spectroscopie Raman des matériaux et nanophases, l'Imagerie Raman de systèmes en fonctionnement. Entre 1992 et 1996 j'avais deux employeurs, le CNRS et un temps partiel à l'ONERA où je menais encore des programmes de synthèse. Maintenant je reste conseiller à l'ONERA et cela se limite à des prestations intellectuelles, à contribuer à l'encadrement de thèses, à identifier les informations, les sujets utiles pour mes collègues de l'ONERA dans les congrès où je vais ou les visites.

BBV : Etiez vous libre de publier quand vous étiez à la Thomson et à l'ONERA ?

PhC : Savoir quel est le degré de publicité à donner à des informations, c'est un art qu'on apprend sur le tas. On apprend à gérer les échanges, à juger d'une situation, à discuter avec des brouillons, etc. C'est très important car c'est une garantie de réussite.
Il faut vraiment encourager la mobilité entre industrie, centre de recherche et de développement et laboratoire académique. On connaît les gens, on connaît la configuration, on sait alors cheminer de concert pour un objectif précis, bénéfique de part et d'autre.

BBV : Et les brevets ?

PhC : Ce sont les industriels qui les prennent. Il faut qu'il y ait de la technologie pour qu'un brevet soit efficace. Plus un brevet est généraliste plus il est facile de le détourner. Ce sont les derniers brevets d'une filière, liés au produit commercialisé qui " rapportent ", les premiers servent à " tenir la filière ". Et de toute façon un brevet a la vie courte, 20 ans dans le domaine de matériaux c'est très court.

BBV : Avez vous des liens privilégiés avec des étrangers ? En particulier fréquentez-vous les meetings de la MRS ?

PhC : J'ai participé assidûment et avec plaisir au meeting annuel de Boston pendant les années 85-95. Maintenant pour des raisons familiales la date ne tombe pas très bien. Je vais assez souvent à l'E-MRS de Strasbourg en juin et régulièrement aux meetings de l'American Ceramic Society, le principal vers le 1er mai, car il y a beaucoup d'échanges et celui de Cocoa Beach en janvier, même s'il y a des sessions fermées, " secrètes ", on apprend énormément. Les e-mail permettent de travailler ensemble au quatre coins du monde.

BBV : Avez vous noté des différences de style de recherche entre les divers pays ?

PhC : Certes oui. En particulier le contraste entre la France et l'Allemagne est saisissant quand il s'agit de monter des projets communs. En Allemagne, seul le chef d'un territoire bien défini peut prendre des décisions mais il est compétent. En France, c'est plus souple mais les compétences ne suivent pas forcément. Les coopérations avec les Asiatiques (Indiens, Vietnamiens, Japonais) doivent se faire grade à grade, en respectant la hiérarchie et on doit prendre son temps. Il faut savoir être lent. Avec les Américains, c'est tout le contraire ; il faut être rapide, même si c'est une mauvaise solution. En Amérique, le temps est une donnée de la recherche, mais pas en France.

BBV : Et la différence est-elle aussi importante dans les relations avec l'industrie ?

PhC : En France, l'industrie est maintenant à la marge. Quand l'Etat était un partenaire industriel il prenait en charge la recherche sur le long terme. Il y a eu des années fastes de 79 à 83 (cela a commencé avant l'arrivée de Chevènement), où l'Etat et l'armée ont fait de gros investissements : c'est l'époque des lancements du Rafale, du porte-avion, des missiles de croisière avec les problèmes de furtivité, d'Ariane, d'Hermès, etc. Mais après le départ de Chevènement, cela a été le commencement de la fin. Maintenant le militaire ne finance plus de recherches sur le long terme : on se pose les questions quand le problème survient sur le prototype. On fait du bottom-up et on dédaigne le top-down. Toute la charge de la recherche à long terme retombe sur le CNRS voire l'université. Et les universitaires français (hors écoles d'ingénieurs) ne veulent pas faire de technologie ou n'y connaissent rien. Alors qu'aux Etats Unis et surtout au Japon, ils ont un pied dans l'industrie, un pied dans l'université et la symbiose est possible.

BBV : Que pensez-vous des initiatives du CNRS pour encourager les liens entre recherche académique et industries ?

PhC : Elles viennent plus de la direction que des commissions. Les détachements sont une formule prometteuse : on touche 15% de salaire en plus pour un détachement dans l'industrie et 30% dans le militaire. Mais la difficulté c'est le retour. Les commissions trouvent bizarre que l'on revienne ; on se retrouve sans salaire pendant 4 mois ! Enfin, maintenant le plus souvent les représentants industriels dans les commissions ne sont pas ceux qui sont dans une position de pouvoir dans leur propre milieu. Ce n'était pas le cas il y a 30 ans.

Fin de l'enregistrement

haut de page

accueil du site

Entretien avec Philippe Colomban, par Bernadette Bensaude-Vincent, 18 février 2003

Lieu : CNRS Laboratoire de Dynamique. Interactions et Réactivité (UMR7075 CNRS & Université Pierre et Marie Curie), 2 rue H. Dunant, 94320 THIAIS, France

Support : enregistrement sur cassette.

Transcription : Bernadette Bensaude-Vincent.

Édition en ligne : Sophie Jourdin.

CARO Paul, 2002-06-20

Sophie Jourdin — 2011-09-19T08:03:18Z

Paul Caro, born in 1934, studied chemistry at the Ecole nationale supérieure de chimie de Paris (ENSCP), where he was attracted to Rare Earths chemistry (the f-elements) by one of the Professors, Félix Trombe (1906-1985) himself a student of Georges Urbain (1872-1938) one of the main promoters of the study of Rare Earths in France. Another student of Urbain teaching at the school was Paul Job who presented the chemistry of mineral "complexes" of d-elements which was to became later coordination chemistry. Paul Caro entered the Centre national de la recherche scientifique (CNRS) in 1955 and started his own research on rare earths elements or lanthanides in Trombe's laboratory. After he got his Ph D degree in 1962, (after two years in the military service …), he spent a few years in the United States, first in Leroy-Eyring's laboratory at Tempe in Arizona, specialized in rare earths non-stoechiometric oxides, then in Ames (Iowa) "the Mecca for rare earth chemists" where Rare Earth separation was done in the framework of the Manhattan project. During the 1960s the rare earths elements, already strategic in nuclear research as a model for separating actinides, became even more important because of their optical properties as unique materials for colour TV screen and lasers. Back in Paris, in 1969, Caro became deputy-director of the Laboratoire des terres rares located on the CNRS campus in Bellevue-Meudon. There he developed the experimental spectroscopy of lanthanides in solids and the theoretical interpretation (simulation) of the spectra (made of numerous sharp lines), using theoretical and mathematical tools, in particular Giulio Racah's algebra and tensor operator formalism made possible by the appearance of powerful computers. He also made extensive use of high resolution electron microscopy. In 1989, Caro started a second career as a science writer and popularizer.
Paul Caro who became corresponding member of the Academy of Sciences in 1978 was awarded the first Lecoq de Boisbaudran Prize set up by Rhodia Company in 2000. He has been the President of the Solid State Chemistry Division of the Société française de chimie (1985-89) and the President of the Association française pour l'avancement des sciences (AFAS) (1991-93).
Our interview is of special interest for rare earths science and applications, for the role of instruments in this domain and for the connections between science and industry in France.

Pour citer l'entretien :

« Entretien avec Paul Caro », par Bernadette Bensaude-Vincent et José Gomes, 20 juin 2002, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article56.

JOSE GOMES (JG) : Dans quelle mesure la chimie des terres rares est-elle une tradition française, dans la ligne des travaux de Georges Urbain ?

PAUL CARO (PC) : D'abord parce que les travaux de Georges Urbain ont porté essentiellement sur la chimie de ces éléments, dans le but de les obtenir à l'état pur. Il fut parmi les premiers en France à les isoler, à préciser leurs poids atomiques et à déterminer quelques unes de leurs propriétés chimiques et physiques. Son apport dans ce domaine fut considérable : il a découvert le Lutétium, mis au point des nouvelles méthodes de séparation de ces éléments et introduit l'usage systématique des moyens physiques (magnétisme) dans l'étude des terres rares et de leurs composés. L'autre grand apport français au domaine est celui d'un amateur : François Lecoq de Boisbaudran (1838-1912). Les séparations conduites par Urbain comportaient une quantité colossale d'opérations répétitives (les cristallisations fractionnées) qui exigeaient patience et détermination. Lorsque j'ai commencé on utilisait les techniques de séparation par échanges d'ions, un peu moins lourdes. Mais l'un des objectifs du laboratoire, au delà de la purification des sels était l'obtention des métaux étudiés chez Urbain depuis le début des années 30. La chimie des terres rares est fortement redevable du savoir-faire acquis par Georges Urbain et son école.

JG :Quelle était la situation de la chimie des terres rares en France quand vous êtes entré à l'Ecole nationale supérieure de chimie de Paris (ENSCP) en 1952 ?

PC : Le laboratoire des terres rares a été fondé par Urbain dans les années 1930, à l'ENSCP. Son deuxième laboratoire à l'ESPCI (Ecole supérieure de physique et de chimie industrielle) a été repris et dirigé par un autre de ses élèves Georges Champetier.
L'ENSCP développait la tradition de l'école de recherche de Georges Urbain grâce à l'enseignement de deux de ses anciens élèves : Paul Job et Félix Trombe. Trombe était plutôt un sous-élève car, faute de diplômes, il ne pouvait pas prétendre à une carrière universitaire. Job au contraire devint professeur à la Sorbonne où il enseignait la chimie des complexes organo-métalliques avec la théorie de Werner, ce qui deviendra par la suite la chimie de coordination. La chimie quantique qui a changé le tout, n'était même pas soupçonnée en France à l'époque où j'ai commencé. On écrivait tel complexe est violet et on n'avait aucune idée des raisons pour lesquelles il était violet ou rose. C'était très descriptif. Aussi les cours de Job nous paraissaient-ils prodigieusement ennuyeux. Par contre, on suivait aussi les cours d'un jeune théoricien nommé Hubert Curien qui nous a initiés à la cristallographie. Ces cours, dans un langage plus moderne, nous paraissaient beaucoup plus intéressants.

JG : Et en ce qui concerne la recherche ?

PC : Trombe a poursuivi deux pistes : l'une était la séparation des terres rares et la préparation de leurs métaux, l'autre, l'obtention de hautes températures dans des conditions qui évitaient les contaminations. Car pour fabriquer les métaux de terres rares, il faut des hautes températures. Trombe avait découvert en 1935 le ferromagnétisme du gadolinium métal, le premier métal magnétique en dehors du groupe du fer. Les propriétés physiques des métaux des terres rares sont très étranges. Trombe les étudiaient avec ses collaboratrices Charlotte Henry la Blanchetais et Françoise Gaume. Les oxydes de terres rares sont des matériaux très réfractaires qui fondent à des températures très élevées. Ce sont les matériaux les plus réfractaires, du moins certains des oxydes. Trombe poursuivait ces deux pistes très originales dans la culture scientifique française. Trombe a eu l'idée du four à électrons puis il a eu l'idée du four solaire. L'avantage de ces fours est que les poudres fondent au sein d'elles-mêmes pour ainsi dire sans creuset. Vous envoyez un flux d'énergie sur une poudre, le seul contact est avec de la poudre non fondue, donc vous n'avez pas de contamination, pas de corrosion du creuset. Quant au métal, c'est encore plus délicat. Le principe est simple : on fait une calciothermie c'est à dire que l'on fait agir du calcium métal sur un halogénure, chlorure ou fluorure, mais le métal rare fondu attaque le matériau du creuset à l'exception de ceux qui sont fait dans un métal "exotique", le tantale. Pour qu'il y ait une bonne métallurgie des lanthanides, il a fallu attendre que l'industrie prépare du tantale assez résistant. Dans les années 1960, il y a eu des feuilles de tantale suffisamment convenables - en provenance d'Autriche, je crois - pour qu'on puisse tenter de les souder sous vide. C'était d'ailleurs des crises nerveuses fréquentes car on loupait 9 creusets sur 10. Et cela coûtait très cher. Avant cela, on se transformait en charbonniers, on creusait de grosses barres de carbone au tour et dans ces creusets on faisait réagir du magnésium avec un mélange d'halogénures fondus et on pouvait obtenir des éponges de métaux rares. La course aux hautes températures était plus sévère pour les oxydes, à cause de leurs très hauts points de fusion, que pour les métaux pour lesquels le four à induction suffisait.

BERNADETTE BENSAUDE-VINCENT (BBV) : Quels étaient les enjeux de ces recherches un peu fastidieuses ?

PC : Trombe a su nouer des alliances : avec l'ESPCI, d'une part, et une autre alliance encore plus importante, avec le CEA (Commissariat à l'énergie atomique). Ce qui a transformé fondamentalement la recherche dans le domaine des terres rares c'est le Manhattan Project. Les terres rares étaient un modèle inactif pour la séparation des actinides nécessaire à la préparation du plutonium. C'est à Ames dans l'Iowa que se trouvait le seul spécialiste américain des lanthanides. Franck Spedding fut convoqué au Pentagone par la Maison Blanche, en 1942 je crois, et chargé de mettre au point des techniques de séparation. Il disposait de tout le personnel qu'il voulait. Il a d'abord essayé les échanges d'ions cela a très bien marché. La séparation des lanthanides est devenue un programme compagnon de la séparation des actinides. Par contre pendant la guerre, en France, les études sur les terres rares n'avaient pas avancé. D'abord Trombe était prisonnier. Et quand il est revenu, les techniques avaient évolué : les échanges d'ions rendaient les cristallisations fractionnées caduques.

BBV : Qu'est-ce qui t'a amené à travailler dans la chimie des Terres rares ?

PC : J'ai commencé à travailler dans le laboratoire de Trombe en 1955. Je dois dire que j'ai été recruté non parce que j'avais des qualités intellectuelles mais parce que je paraissais suffisamment costaud pour porter des flacons de 5 litres que l'on transvasait sans cesse à la sortie des colonnes échangeuses d'ions. C'était un travail de manoeuvre, en fait, la séparation des terres rares.
De plus, il y a une deuxième raison, à peine avouable, qui m'attirait dans le personnage de Trombe. A l'époque, avec mes camarades de l'Ecole de chimie, nous fréquentions beaucoup les catacombes, nous étions passionnés de spéléologie et Membres actifs du Spéléo Club de Paris. Or Trombe était l'un des grands spéléologues français. Il avait fait des explorations extraordinaires, notamment dans le Vercors. C'était pas tellement les terres rares qui m'attiraient, c'était le personnage. Il était un très mauvais professeur, il bafouillait tout le temps. Mais c'était un gentilhomme, excellent cavalier, grand sportif, grande allure. Il avait un côté gascon, un côté condottiere. Il a toujours souffert de ne pas avoir les diplômes qui lui auraient permis d'embrasser une carrière universitaire.

BBV : Pourrais-tu préciser quel est le problème avec les oxydes et avec les métaux ?

PC : Les oxydes, on l'a vu, ont un très haut point de fusion, ce sont donc des matériaux réfractaires. Pour préparer les métaux des terres rares, ce qui était l'un des objectifs de la recherche dans les années 30, il faut faire des calciothermies, et atteindre une température suffisante pour fondre le métal produit de façon à ce qu'il se sépare des sels fondus. L'inconvénient majeur est que les métaux des terres rares fondus attaquent - ou attaquaient à l'époque - tous les matériaux connus. On savait donc à peu près quelle technique il fallait utiliser mais on ne savait pas dans quoi le faire. Trombe s'était mis dans l'idée d'utiliser des systèmes d'auto-creusets, comme je l'expliquais tout à l'heure. Si l'on envoie un faisceau d'électrons ou un faisceau de photons concentrés sur un point, ce point va fondre au contact de la poudre elle-même ; ainsi il n'y aura pas de contamination. Alors on pouvait imaginer d'appliquer cela aux éponges métalliques préparées à base de sels fondus. Ces sortes d'éponges pleines de trous pouvaient être agglomérées un peu comme on faisait le fer au Moyen Age : on tapait dessus jusqu'au moment où il s'agglomérait parce qu'on ne pouvait pas le fondre. Peut-être pourrait-on trouver une technique de fusion sous vide qui permettrait de raffiner ainsi le métal ? Trombe a eu l'idée d'utiliser le soleil qui permet d'obtenir facilement, en concentrant le rayonnement, des températures ponctuelles de l'ordre de 3000°C.
C'est grâce à la spéléologie qu'il a pu installer un four solaire dans les Pyrénées. Il explorait une grotte dans le Lot avec l'armée, plus précisément avec le Colonel Bergeron, devenu Général plus tard, et au cours de l'expédition d'exploration, comme ils étaient assis dans l'eau - ce qui arrive souvent - Trombe racontait à Bergeron qu'il cherchait un endroit ensoleillé pour installer un four solaire. Les miroirs de DCA à Meudon ne suffisaient pas étant donné la fréquence des nuages en région parisienne. Alors le colonel lui a dit : l'armée peut mettre à votre disposition un fort dans une région bien ensoleillée. Il y en a un à Nice, un à Montlouis (en Cerdagne). Entre le fort de Cimiez à Nice et celui de Montlouis, Trombe, qui était pyrénéen, a choisi Montlouis. C'était probablement une erreur stratégique pour la suite car Nice a plus de prestige et Montlouis est très isolé.

JG : Quel était votre premier sujet de recherche ?

PC : J'ai fait une thèse sur les alliages de magnésium et d'yttrium préparés en creusets de carbone par réaction de magnésium fondu avec des halogénures de terres rares. J'avais obtenu ainsi un peu d'yttrium en éponge car il s'alliait avec le magnésium. On évaporait et on obtenait une éponge d'yttrium. C'était un truc lambda mais j'avais essayé d'utiliser un peu les appareils modernes comme la sonde de Castaing.

BBV : La sonde de Castaing ? Qu'est-ce que c'est ?

PC : C'était un microscope électronique qui permettait en analysant les électrons ou les photons ré-émis par l'échantillon, d'avoir une indication de la composition chimique de l'objet à une échelle très petite. C'était important pour les minéralogistes. Il y avait une sonde au BRGM (Bureau de Recherche Géologique et Minière) où j'allais dans le 15° arrondissement, pour repérer les compositions des alliages. Quand les phases se séparent, de petits cristaux apparaissent. On en fait l'analyse. Maintenant c'est une technique standard et très utilisée.

BBV : Quels sont les instruments dont disposait le laboratoire de Trombe ?

PC : C'était un arsenal de chimie préparative avec des fours à induction : hautes températures et vide. Il y avait la balance magnétique style Urbain qui permettait de contrôler les purifications et une thermobalance inventée par un autre élève de Trombe, Jean Loriers. Pour le reste il y avait des techniques chimiques ordinaires. Un peu plus tard au début des années 60, sont arrivés les rayons X et la fluorescence X, une technique qui permettait d'analyser quantitativement et individuellement les terres rares. L'instrumentation n'avait pas encore acquis le niveau de complexité qu'elle devait connaître à la fin des années 60.

BBV : Quelles étaient les relations entre le laboratoire de Trombe et les autres laboratoires de chimie du solide en France dans les années 1950-60 ?

PC : Dès avant mon arrivée au Laboratoire (1955), il y a eu une sorte de révolution de palais à Paris. Une scission dans la communauté scientifique française entre ceux qui, comme André Chrétien ou Paul Laffite ont occupé les chaires de la Sorbonne et d'autres qui furent éloignés et durent émigrer à Bellevue. Le laboratoire des terres rares, situé à l'ENSCP depuis sa création dans les années trente a été déménagé sur le campus du CNRS à Meudon-Bellevue. Le domaine de Meudon Bellevue appartenait à la danseuse américaine Isadora Duncan, elle l'avait légué à sa mort au Bureau des inventions qui y avait installé quelques laboratoires techniques, sur la bicyclette, la photographie et une station d'essais de moteurs. Le CNRS, à sa création à la fin des années 30, a hérité du Bureau des Inventions et donc du terrain de Meudon. Là on a envoyé un certain nombre de laboratoires de recherche plutôt encombrants, demandant de l'espace mais aussi dirigés par des personnages plutôt hauts-en-couleurs. Dans le lot, il y avait Trombe, Boris Vodar (spécialiste des hautes pressions), Claude Bonnemay (un électrochimiste), et aussi Aimé Cotton qui a installé à Meudon un laboratoire de physique et d'optique. Meudon abritait déjà le grand électro-aimant de l'Académie des Sciences. Ces laboratoires qui forment le noyau du CNRS avaient pour mission de faire de la recherche, pas de l'enseignement. D'où leur structure différente des laboratoires de la Sorbonne - dont l'archétype en chimie minérale était le laboratoire de Chrétien - qui avaient une double mission de recherche et d'enseignement. Les laboratoires du CNRS jouissaient de conditions favorables mais ils étaient un peu tenus à l'écart par ceux de la Sorbonne. Chrétien, détenteur de la chaire de chimie minérale, était le spécialiste du théâtre chimique dans la mesure où il avait beaucoup d'assistants qui organisaient des présentations avec des expériences toujours spectaculaires. Laffite avait la chaire de chimie générale et puisait généreusement pour son cours dans des livres américains, comme on l'a découvert plus tard. Tous deux avaient beaucoup d'assistants, beaucoup d'élèves qui, par la suite, ont peuplé l'université. Alors que les laboratoires de Meudon n'avaient pas d'élèves car ils étaient loin des milieux universitaires. Or pas d'élèves signifie pas de descendance. C'était une stratégie des professeurs de la Sorbonne d'éloigner ces gens qui avaient une grande gueule. Ils avaient un côté "les mains dans le cambouis". Ils avaient des gros instruments. Ils étaient des expérimentateurs, pas trop portés sur la théorie. Trombe était un excellent expérimentateur. Je l'ai vu, par exemple, fermer dans des conditions acrobatiques des ampoules scellées, il n'y avait que lui qui pouvait faire ça.
Le développement du campus de Bellevue s'est fait un peu en opposition à celui de la Sorbonne. Par contre, le campus CNRS de Vitry s'est développé en nouant des liens forts avec l'université et avec les écoles d'ingénieurs. Conscients du problème des élèves, Georges Chaudron, et Jean Bénard, professeurs, se sont ingéniés à squatter les comités du CNRS pour recruter. Il serait intéressant d'étudier la manière dont les laboratoires universitaires en chimie ont accaparé les postes de chercheurs CNRS.

BBV : Encore faudrait-il avoir accès aux archives.

PC : Paul Hagenmuller (élève de Chrétien) a encore mieux réussi car il a disséminé, il a joué la carte de la province et s'est créé une clientèle d'obligés. D'où des paysages contrastés pour la physique et la chimie en France. La physique se concentre sur l'axe Orsay-Grenoble, tandis que la chimie se déploie comme une juxtaposition de baronnies locales : Nantes, Bordeaux, Rennes, Caen, Paris. Il y avait des rivalités entre ces baronnies et aussi des alliances, par exemple, Paul Hagenmuller et Robert Collongues (lui même à cheval sur l'Ecole de Chimie et Vitry). A Rennes, au contraire, Prigent a eu des élèves plus indépendants et agressifs comme Jacques Lucas et Grandjean qui ont développé des pistes originales avec des applications industrielles. A Caen il y avait Deschanvres avant Bernard Raveau. Dans le domaine des terres rares, il ne faut pas oublier l'oeuvre de Jean Flahaut qui a longtemps dirigé à la Faculté de Pharmacie à Paris un laboratoire consacré à l'étude des sulfures des lanthanides.

BBV : Quels étaient les liens entre Chaudron, Collongues et Trombe ?

PC : Collongues était plus spécialisé dans les oxydes. Chaudron, Bénard et Collongues à Vitry ont fait union avec Trombe pour les hautes températures. Flahaut y participait aussi, de plus il était l'"héritier" d'Henri Moissan (1852-1907), l'inventeur du premier four "haute température" conservé à la Faculté de Pharmacie. La métallurgie exigeait des hautes températures. Par exemple des fours à images (il y en a un très joli à l'ENSCP).
Grâce au don de l'armée, Trombe avait le plus grand four solaire du monde. Quand il a commencé à faire des expériences avec ce four, il avait pour collègue Marc Foëx. C'était un chercheur extraordinaire - à mettre sur ta liste - qui a fait énormément d'études sur les systèmes d'oxydes mixtes et qui avait mis au point des méthodes astucieuses pour l'établissement des diagrammes d'équilibre. C'était un solitaire, un chercheur remarquable. Mes enfants l'appelaient le professeur Tournesol car il en avait l'allure. Donc sur le créneau des hautes températures il y avait Trombe, Foëx, Collongues, Chaudron. Ils ont formé une Société des Hautes Températures, dont on doit pouvoir retrouver les archives et qui a publié une revue. Chaudron et Trombe ont, en plus, publié un Traité des hautes températures, chez Masson dans le style des fameux "Pascal" de Chimie minérale. Tu peux y trouver des pistes historiques. Il y avait dans la série des "Pascal" un Tome consacré aux terres rares publié dans les années 30 et réédité par Trombe avec mise à jour dans les années 60 en deux volumes dans lequel vous trouverez des mises en perspectives historiques de l'histoire des recherches sur les lanthanides. Les membres de ce petit groupe des hautes températures étaient à la fois copains et rivaux. Comme Trombe s'intéressait de plus en plus à l'énergie solaire et de moins en moins à la séparation des terres rares, c'est un autre élève de Trombe, Jean Loriers, qui a pris en mains la séparation des terres rares. Assez rapidement il est apparu que les propriétés intéressantes des terres rares n'étaient pas les propriétés chimiques.

BBV : A quel moment se situait ce tournant dans ta propre trajectoire ?

PC : Je suis parti aux Etats-Unis en 62 après un petit stage à Montlouis. J'ai appris, il n'y a pas si longtemps, qu'à l'époque où je faisais ma thèse, on étudiait exactement la même chose aux Etats Unis, même technique de préparation d'Yttrium, mais en grande quantité, dans le plus grand secret. Pourquoi ? Parce que l'administration américaine s'était mis dans la tête de faire un avion à propulsion nucléaire ! Pour cela il fallait des grandes quantités d'yttrium pour des raisons de poids (l'yttrium est un élément léger) et pour des raisons de protection. Puis quelqu'un a dû dire au Congrès que ça n'était pas très raisonnable ! Donc ils ont arrêté le projet et, du coup, ils avaient de grandes quantités d'yttrium au moment où est tombée la demande de l'industrie des télévisions. La télévision était en noir et blanc et il y avait beaucoup d'études pour une TV couleur. On s'est rendu compte que le seul matériau qui pouvait fournir le rouge non saturable pour les écrans c'étaient les composés d'europium dilué dans une terre rare "inactive" comme l'yttrium. C'est RCA, je crois, qui a trouvé cela. Ils se sont fait piéger car ils ont présenté leur machine dans un salon et il y avait un type qui a regardé l'écran avec un petit spectroscope et qui a vu que le rouge formait des raies et non des bandes. Les autres composés - sulfures - donnaient des bandes. Il n'était pas difficile de trouver l'élément de base, c'était une terre rare.
J'étais allé aux Etats-Unis dans le laboratoire de Leroy Eyring pour étudier des points très particuliers de certains oxydes non-stoechiométriques de terres rares : des oxydes entre deux valences, ce que l'on appelle aujourd'hui "des valences mixtes", comme ceux du cérium, du praséodyme et du terbium pour des raisons pas claires à l'époque. En plus il n'y avait pas un oxyde intermédiaire mais 7 ou 8. Leroy Eyring avait mis au point des méthodes thermodynamiques pour mesurer la composition de ces oxydes. J'ai utilisé cela avant d'aller à Ames qui me paraissait être la Mecque des terres rares car c'était là qu'avait eu lieu la séparation pour le projet Manhattan et tous les lanthanides y étaient disponibles. Il y avait un gros laboratoire national dans lequel on avait la possibilité d'étudier les métaux. J'y ai travaillé avec John Corbett qui avait étudié des composés bizarres des lanthanides avec des halogènes. J'ai étudié chez lui le système entre le thulium métal et le trichlorure de thulium dans lequel j'ai trouvé un système non-stoechiométrique à valences mixtes analogue à celui des oxydes. Il y avait toutes les facilités possibles pour faire des expériences. A cette époque j'ai aussi étudié la cristallochimie des lanthanides et publié en 1967 la description des oxysels des lanthanides qui forment une catégorie à part de composés lamellaires à laquelle d'ailleurs certains oxydes appartiennent. Dans mon travail, les structures étaient décrites au moyen de polyèdres centrés sur les anions (alors que d'habitude on utilise le cation).

JG : Qui finançait ce labo ?

PC : C'était l'US Atomic Energy Commission. Il y avait toutes les sources de métaux gratuitement si je puis dire, puisqu'ils les produisaient. Ainsi il y avait beaucoup de thulium qui est un métal très cher.

BBV : Quelles étaient les techniques utilisées à Ames ?

PC : A cette époque il y eut un changement profond dans toute cette chimie préparative du fait de l'irruption des techniques mathématiques. D'abord il y eut la révolution apportée par la théorie des groupes dans l'explication des propriétés des composés de transition, ou composés des éléments d, (la lettre d signifie que pour ces éléments le nombre quantique orbital des derniers électrons est égal à 2), les anciens complexes dont nous parlait Job. Elle a permis de reconnaître que le spectre dépendait de la symétrie cristallographique du site. La couleur changeait suivant qu'il était tétraédrique ou octaédrique. On a vu alors se former les théories du champ du ligand, les théories du champ cristallin issues de la combinaison de la théorie des groupes et de la théorie quantique.
Il y a eu une deuxième révolution, que je trouve exemplaire dans l'histoire des sciences parce qu'elle est due à un homme seul, un physicien israélien, durant la guerre de 1948 en Israël. Giulio Racah, était spécialiste de la théorie de la spectroscopie atomique qui s'efforçait de comprendre les spectres d'arcs ou d'étincelles. Ces spectres sont dus à des atomes neutres ou une fois ionisés et ils sont caractérisés par un très grand nombre de raies. L'interprétation du spectre de l'hydrogène était facile mais dès que cela dépassait deux électrons dans le système cela devenait trop difficile car on voit des milliers de raies. Des méthodes mathématiques avaient déjà été mises au point pour tenter de comprendre cette spectroscopie.
Racah, qui avait la capacité de faire des calculs aussi bien qu'un ordinateur, a mis au point une méthode à base d'opérateurs tensoriels pour calculer les spectres des éléments pluri-électroniques. Il est allé au-delà de la théorie des tenseurs de rang 1 en inventant des nombres qui forment ce que l'on appelle l'algèbre de Racah.
Cette algèbre a rendu possible l'interprétation des spectres des atomes poly-électroniques et donc des configurations 4f N, (N électrons 4f, N varie de 1 à 14 du cérium au lutétium), celles des lanthanides dans les solides (la lettre f signifie que le nombre quantique orbital des derniers électrons de l'atome est égal à 3). Si on prend un spectre d'un cristal de lanthanide, du néodyme par exemple on va obtenir avec un spectromètre ordinaire dans le domaine Ultraviolet-Visible-Infrarouge, plus d'une centaine de raies très fines. A quoi correspondent ces raies ? L'interprétation n'est apparue qu'à la fin des années 60 parce qu'on avait un outil théorique, mais aussi des outils expérimentaux. Car, pour observer des spectres convenables, il faut travailler à la température de l'hélium liquide. Il fallait donc que l'instrumentation s'accompagne de l'utilisation de systèmes à basses températures.

BBV : Pourrais-tu préciser les apports théoriques et mathématiques ?

PC : Par comparaison avec l'effet de champ cristallin pour les éléments d, dits de "transition", dans le cas des éléments f l'ampleur de l'effet de l'hamiltonien (l'opérateur qui exprime l'ensemble des actions extérieures sur les états d'énergie de l'atome) est beaucoup plus faible. Par conséquent les spectres des lanthanides conservent dans les solides une allure très "atome libre", ce qui justifie l'usage des théories de la spectroscopie atomique. On a donc commencé à classer les opérateurs qui intervenaient sur les états de base de la configuration. Pour les configurations 4f N, que l'on n'obtient que dans le solide et pas dans les spectres d'étincelle, le nombre d'états n'est pas si énorme. Dans le cas du néodyme, c'est 364, dans le cas du gadolinium c'est 3600 et quelque chose. Donc on a une base, un corpus d'états chacun caractérisés par une suite de nombres quantiques, sur lesquels on peut appliquer des opérateurs qui sont la répulsion inter-électronique, le couplage spin-orbite, enfin toute une série d'opérateurs dont certains étaient connus au début du siècle. Mais c'est seulement grâce à l'algèbre de Racah qu'on a su calculer les éléments de matrice de ces opérateurs. Puis on appliquait sur tout cela, en plus, le champ cristallin qui, lui, dépendait de la symétrie au site de l'atome. C'est donc une conjonction entre des outils mathématiques : d'une part une théorie des groupes assez sophistiquée avec des groupes continus (j'ai écrit un livre là-dessus, c'est pas un truc qui se lit facilement il faut vraiment en avoir besoin) et d'autre part la théorie quantique appliquée avec le moins d'approximations possibles qui a rendu possible des comparaisons entre le calcul et l'expérience. On pouvait mesurer un spectre et à partir de cela faire des calculs. Maintenant on arrive à obtenir des spectres simulés ! Les spectres des lanthanides sont extrêmement précis et en général la théorie n'arrive pas au niveau de précision de l'expérience. On peut mesurer des effets hyper fins qui sont dus au noyau donc aux isotopes pour certains éléments. Il faut toujours ajouter des hamiltoniens ...
Donc ce qui a changé la manière d'envisager les terres rares c'est l'apparition de ces possibilités d'interprétation qui venaient des mathématiques et de la théorie quantique.

BBV : Peut-on revenir sur les enjeux industriels des terres rares ?

PC : Si on utilise l'europium pour les écrans couleurs c'est parce que ses propriétés de luminescence dans les solides sont spectaculaires. Comme elles dépendent de la pureté, la préparation n'est pas évidente. C'est ainsi qu'on est tombé dans une bataille industrielle sur la qualité des luminophores qui a fini par une victoire de Rhône-Poulenc. Rhône Poulenc a été le seul fabricant mondial de terres rares pures pour les écrans de télévision.

BBV : De quand date l'usine de La Rochelle ?

PC : Elle est très ancienne car il existait en France une industrie des terres rares depuis le début du siècle pour la fabrication de pierres à briquet et d'additifs pour le verre afin d'obtenir de meilleurs indices de réfraction. On les utilisait aussi - et on les utilise toujours - comme colorants pour la porcelaine. Enfin, il y a les mélanges de terres rares pour les catalyseurs. Aujourd'hui c'est important pour les automobiles mais, au début, c'était surtout pour le cracking du pétrole. Ce qu'a su faire l'usine de La Rochelle, (aujourd'hui elle appartient à la Société Rhodia), c'est la mise au point d'une technique de séparation non plus par échange d'ions mais par échange de solvants. Cette technique plus ou moins secrète leur a assuré la conquête du marché à l'époque où se multipliaient les applications. Car il y a aussi la luminescence des tubes fluorescents et surtout l'apparition des lasers de puissance au néodyme.

JG : Comment fonctionnent ces lasers ?

PC : La caractéristique des lanthanides dans les solides, c'est la possibilité qu'a l'atome de grimper sur les échelons d'une échelle d'énergie qui va de l'IR jusqu'à l'UV. Dans le cas du néodyme, on peut faire monter avec un flash ordinaire l'atome sur un niveau situé au milieu du visible. Il va redescendre en émettant un photon infrarouge qui peut être amplifié. De là les lasers au néodyme. Cette échelle d'énergie, c'est la propriété essentielle des terres rares et on ne la soupçonnait pas quand j'ai commencé ma carrière. On l'a découverte à la fin des années 60 et depuis on trouve les petits tableaux des états d'énergie affichés dans les bureaux, ce qui était impensable dans les années 50.

BBV : Est-ce qu'il y a eu à ce moment là dans les laboratoires français un investissement industriel ? Et sous quelle forme ? Contrats ?

PC : Il y a eu pas mal de contrats militaires car l'armée explorait toutes les possibilités pour faire des détections à infrarouge, des lasers. L'industrie s'est intéressée à des préparations ultrapures pour les lasers (les lasers qu'on utilise en chirurgie sont des lasers au néodyme). Le laboratoire de Collongues, par exemple, a fait la promotion de l'alumine-béta dopée néodyme comme matériau laser. Donc il y a eu une recherche soutenue par l'armée et par l'industrie.
Il y a eu aussi l'immense projet américain de fusion nucléaire par laser au néodyme, organisé en Californie à Livermore (le National Ignition Laboratory). Il fait appel à des lasers qui ont un diamètre de plusieurs dizaines de cm. On espère provoquer la fusion en concentrant le faisceau sur un mélange deutérium-tritium contenu dans une micro ampoule. D'autres terres rares sont utilisées dans des disques qui polarisent le faisceau. Donc les applications optiques ont pris le dessus. Le Laboratoire National d'Argonne (près de Chicago) et les laboratoires de l'armée ont démêlé les principes directeurs de toute cette spectroscopie pour exploiter cette propriété des lanthanides.

BBV : Et en France ?

PC : Maintenant tout le monde fait cela mais à l'époque on était les seuls au laboratoire de Bellevue à maîtriser un peu ces questions. Plus tard, une autre élève de Trombe, Françoise Gaume, a construit à l'Université de Lyon un grand laboratoire consacré à l'étude de la luminescence, dirigé ces dernières années par Georges Boulon.

BBV : A l'époque c'est à dire quand ?

PC : Quand je suis rentré des Etats-Unis, vers 1968. J'ai hésité à rentrer car on m'avait donné un poste aux Etats-Unis, mais ici on m'a donné un poste de maître de recherche au CNRS alors que j'étais relativement jeune. J'ai pris la sous-direction du laboratoire des terres rares qui était dirigé par Jean Loriers à l'époque avant qu'on le fractionne en trois groupes centrés sur des structures différentes. On a travaillé sur les propriétés optiques. Les propriétés magnétiques ce sont plutôt les groupes de Grenoble, les successeurs de Louis Néel qui les ont étudiées. Cela a donné l'autre grosse application technologique avancée des terres rares : les petits aimants qu'on utilise dans les téléphones, les baladeurs, etc. On a pu multiplier la puissance des aimants par 1000.
Nous, on a travaillé sur les propriétés optiques tandis que le groupe de Jean-Claude Achard, un autre élève de Trombe, s'est consacré aux propriétés des composés métalliques complexes, dans lesquels il y a des phénomènes physiques spectaculaires, comme les solitons. Cela passionnait les physiciens et c'était des objets de physique pure.
Et puis ma collègue Annick Percheron, une autre élève de Trombe, a beaucoup étudié les hydrures à base de terres rares qui sont des matériaux idéaux (des alliages Lanthane-Nickel) pour le stockage de l'hydrogène. D'où l'intérêt pour des moteurs à hydrogène où l'hydrogène est piégé dans un solide, donc pas de problème de sécurité. Le problème, c'est que le nickel est un élément lourd d'où le poids du véhicule et donc son autonomie réduite. La technologie existe mais c'est la sociologie de l'automobile qu'il faut changer.

BBV : Quels instruments avez-vous exploité au laboratoire de Bellevue après ton retour des USA ?

PC : On a développé les spectrographes et surtout la microscopie électronique à haute résolution que j'avais vu aux Etats Unis. J'ai assisté à un congrès au National Bureau of Standards à Washington sur les oxydes en 1972. C'était un congrès restreint, une trentaine de personnes. Quand les Japonais ont présenté les premières images de colonnes d'atomes observées avec un microscope électronique à haute résolution, tout le monde a été impressionné. Ils avaient un opérateur extraordinaire. Il faut dire que tout dépend du talent de l'opérateur en microscopie électronique. Sinon on ne voit pas grand chose car le fond de lumière est très bas. C'est un peu comme le photographe qui appuie sur le bouton au bon moment. Il y a de mauvais opérateurs et il y a des opérateurs de génie.

BBV : Comment avez vous appris cette technique à Bellevue ?

PC : J'avais dans mon équipe Gérard Schiffmacher qui avait ce talent et il était aussi très fort pour les calculs. Car on ne peut croire les images en microscopie électronique que si on a simulé l'image à partir d'un modèle de la structure. Un objet déterminé correspond à une infinité d'images différentes. Pour savoir si cette séquence d'images correspond à quelque chose de réel, il faut simuler la structure et voir si la structure engendre une séquence d'images similaires à ce qu'on observe en fonction de la focalisation des instruments. C'est une technique classique qui aujourd'hui se fait presque automatiquement. Mais à l'époque cela exigeait des calculs de diffraction assez compliqués en 3 dimensions. Il fallait maîtriser les programmes pour obtenir des images simulées que Gérard réussissait très bien. L'invasion des ordinateurs est un aspect crucial dans l'évolution de la chimie des solides.
J'avais dans le laboratoire une équipe qui étudiait les couches minces d'oxydes de terres rares avec Michel Gasgnier. Je me suis aperçu un peu par hasard que ces oxydes étaient de merveilleux objets pour la microscopie électronique à haute résolution. Ces oxydes présentent des textures lamellaires qui en font des objets parfaits de faibles épaisseurs. On avait là des matériaux qui permettaient d'obtenir des clichés avec des résolutions atomiques et donc d'étudier toute une série de phénomènes inconnus dans ces oxydes, comme des mâcles ou des dislocations, ce que nous avons fait avec Claude Boulesteix, alors à l'Université d'Orsay, et d'autres Collègues physiciens. Dans les années 70, on a fait les premiers plaidoyers pour l'utilisation de la microscopie électronique dans la chimie du solide en France. Donc on avait en somme transformé un laboratoire de préparation chimique un peu lourde en un laboratoire centré sur deux techniques physiques, la spectroscopie à basse température et l'examen de la matière avec le microscope électronique à haute résolution.

BBV : Qui finançait ces instruments ? Le CNRS ou l'industrie ?

PC : On avait quelques contrats avec l'industrie. Mais c'est le CNRS qui a financé les microscopes électroniques. Quand j'ai rapporté les photos avec colonnes d'atomes résolues du Congrès de Washington à Fernand Gallais qui dirigeait à l'époque la chimie au CNRS, je lui ai dit : "voilà ce qu'on fait aujourd'hui avec les microscopes électroniques fabriqués par les Japonais". Il ne m'a pas demandé à quoi cela servait. Il m'a dit "combien ?". On a acheté deux microscopes avec nos collègues physiciens de Bellevue. C'était l'époque où les directeurs de la chimie avaient cet esprit condottiere qu'avait Trombe. Le précédent directeur du CNRS avait créé le grand microscope de Toulouse, microscope à haute tension. C'était Gaston Dupouy, un copain de Trombe, qui dirigeait le labo de Toulouse. Notre microscope à nous était à basse tension, donc beaucoup moins cher. Et finalement ces microscopes à basse tension avaient des performances supérieures aux autres.

BBV : Donc il y avait une foi dans les grands instruments au CNRS ?

PC : Oui. C'est d'ailleurs à cette époque là que Trombe a eu l'autorisation de construire le four solaire d'Odeillo, dix fois plus gros que le four solaire de Montlouis. Avoir des grands instruments pour voir plus loin, c'était la stratégie.
Depuis les Japonais ont introduit la miniaturisation. Un instrument qui faisait autrefois trois étages de haut, a aujourd'hui une taille raisonnable. Mais le labo de Toulouse a gardé comme une pièce archéologique le premier microscope à haute tension. C'est un lieu où la chimie du solide a été étudiée sous l'angle expérimental.

BBV : Quels étaient les autres instruments utilisés en chimie du solide ?

PC : A cette époque, la chimie du solide reposait sur l'exploitation d'une autre technique, les rayons X, c'est à dire la cristallographie. Cela a été rendu possible grâce à l'arrivée des ordinateurs qui permettaient de faire les calculs. Nous-mêmes quand on a commencé à faire de la spectroscopie on était obligé d'aller passer des paquets de cartes dans l'ordinateur de l'université d'Orsay. C'était fastidieux. Il fallait des heures de calcul. L'informatique a révolutionné la chimie des solides conjointement avec les basses températures. Si Bernard Raveau (de Caen) a raté le Prix Nobel sur la supraconductivité c'est parce son laboratoire n'était pas équipé pour faire des expériences à basse température. Il fallait la température de l'hélium liquide et non celle de l'azote liquide.

BBV : Comment se traduit au niveau des résultats la différence entre une chimie basée sur le microscope électronique et une chimie basée sur les rayons X ? Pouviez-vous faire des relations entre structure et propriétés comme en cristallographie ?

PC : Oui, on voyait des mâcles (des défauts étendus), des dislocations, que la cristallographie ne permettait pas de voir. Le microscope électronique donne cette vision sur la sociologie intime du cristal qu'on ne peut obtenir avec les rayons X. Il y avait aussi les propriétés de surface qui ne peuvent être découvertes que par des instruments comme le microscope à balayage. A Bellevue on avait réussi à monter un groupe de laboratoires, une sorte de soviet, l'Action Locale de Bellevue (ALB), que j'ai présidée pendant longtemps. Son but était de faire du lobbying pour l'achat d'instruments. C'est ainsi qu'on a eu un microscope électronique, un microscope à balayage, des spectrographes. L'idée était que, pour avoir des informations en chimie, il fallait avoir des instruments. On était aidé par le laboratoire de physique de Jean Philibert spécialisé dans la microscopie électronique. En fait, comme nous l'avons montré avec la simulation des susceptibilités paramagnétiques des composés des lanthanides, la relation structure-propriété est très complexe et ne peut que difficilement se déduire de la connaissance des structures seules. Dans le cas cité la propriété magnétique dépend d'un "super espace" qui a une dimension (toujours supérieure à 3 !) imposée par la symétrie cristalline au site et qui se déduit de l'application des règles de la théorie des groupes au "champ cristallin". Ces concepts ont beaucoup de mal à pénétrer la conscience, un peu matérialiste, des chimistes - qui croient que quand on a la structure, on a tout...

BBV : Est-ce qu'il y a eu des échanges interdisciplinaires au sein du laboratoire de Bellevue ?

PC : Oui, on échangeait nos technologies, on a travaillé entre nous. Le groupe des laboratoires de Bellevue, j'aurais voulu en faire l'équivalent d'un laboratoire du Max Planck. On a mené une longue bataille administrative. Il y avait quatre secteurs à Bellevue : sciences physiques, sciences chimiques, sciences de la vie, et sciences humaines, des préhistoriens. Il a été impossible de faire un groupe uni. Toutes les documents de cette période sur l'action de l'ALB, je les ai donnés aux archives du CNRS conservées à Gif sur Yvette.

BBV : Quelles étaient les industries avec qui ces laboratoires CNRS avaient des liens ?

PC : On avait des contrats d'étude avec la DRET (Direction des Recherches et Etudes Techniques) une direction militaire. Avec Péchiney, avec Rhône Poulenc surtout et, bien sûr, des liens de conseils pour l'industrie mais à titre individuels. On a eu quelques thésards payés par l'industrie. Mais l'industrie n'imposait pas, ne pesait pas d'un poids trop lourd (du moins c'est ainsi que je l'ai perçu ; peut-être que je me suis fait manœuvrer). L'industrie récoltait des thèses et renforçait son système sans donner d'argent.

BBV : Qu'est-ce qui orientait les décisions d'orientation de recherche ? Les contrats avec l'industrie ?

PC : Il y avait deux choses. D'abord beaucoup de décisions provenaient de collaborations avec d'autres laboratoires de Nantes ou de Bordeaux. Ils apportaient leurs produits et nous on étudiait les spectres puisqu'on avait la technique, on dérivait les simulations optiques et magnétiques. On publiait en commun. Ensuite, ils se sont équipés et donc on a fait moins de collaborations de ce genre.

BBV : Est-ce que la chimie des terres rares a changé depuis cette époque ? Est-ce que l'approche matériaux n'a pas supplanté les autres ? Est-ce qu'il reste des enjeux fondamentaux ?

PC : Lors d'un congrès récent, je n'ai pas eu l'impression qu'il reste des enjeux fondamentaux. Aujourd'hui les techniques se sont raffinées mais il n'y a pas de changement fondamental. J'ai cependant le sentiment qu'il y a des choses à étudier du coté de la dynamique des réactions. A la fin, dans les années 90, j'ai étudié avec Michel Gasgnier les phénomènes de sonochimie associés à certaines réactions paradoxales sur les oxydes non stœchiométriques. Par contre, les enjeux techniques se sont multipliés. Aujourd'hui les terres rares sont utilisées en biologie parce qu'elles se substituent au calcium. Le calcium n'a pas de propriétés physiques alors que les terres rares en ont. On peut ainsi repérer les protéines chargées en terres rares. Les techniques de synchrotron ont permis d'obtenir des informations plus précises sur les sites cristallographiques et même sur les parties actives des sites en question. En biologie les terres rares permettent d'accélérer l'obtention de la structure des protéines pour laquelle il y a un énorme marché industriel, en pharmacie. Les techniques synchrotron exploitent les effets de seuil d'absorption X des éléments lourds. Généralement on emploie le sélénium mais on peut utiliser les terres rares.
On voit en plus beaucoup d'applications énergétiques : les batteries de téléphone portable sont souvent aux hydrures de lanthane. On trouve aussi des terres rares dans les piles à combustible. Le grand espoir c'est le catalyseur d'automobile pour lequel le cérium (ou des systèmes mixtes) s'est révélé un point de passage indispensable.

BBV : Quelle est la position des Français dans ces domaines ? Sont-ils compétitifs ?

PC : Oui les terres rares restent une spécialité française depuis Lecoq de Boisbaudran et Urbain. C'est encore un domaine très important en physique et en chimie. Le laboratoire de Grenoble est très important. Les ferrites, invention de Louis Néel et Félix Bertaud sont des oxydes à base de terres rares. L'école de Grenoble est orientée vers les métaux. Pour les propriétés optiques, il y a Paris, Lyon, et surtout Rennes qui a développé les fibres optiques à répétiteur dopé à l'erbium. Le CNET (Centre national d'études des télécommunications) avait beaucoup travaillé là dessus. François Auzel, ingénieur du CNET était un petit génie. Il a découvert ce que j'appelle l'effet Auzel : la possibilité d'exciter une luminescence visible avec un faisceau infrarouge, c'est à dire qu'en utilisant une énergie plus faible on peut obtenir une énergie plus élevée grâce à une addition de photons. Il faut mettre plusieurs terres rares. C'est utilisé par la poste pour marquer les enveloppes, je crois.

BBV : Cela a été découvert dans les années 70 et dans un laboratoire industriel ?

PC : Oui mais c'est un laboratoire d'Etat à vocation industrielle. Auzel était remarquable et a été injustement mis sur la touche.

BBV : Et des laboratoires du CNRS qu'est-ce qui est sorti comme découverte concernant les terres rares ?

PC : Cela dépend comment tu entends cela car dans ce genre de recherches on obtient souvent de petites avancées. Et qu'est-ce qu'on appelle une découverte ? A la question : "qui est-ce qui a découvert la télévision en couleurs ?", je réponds fermement Georges Urbain qui a le premier observé la luminescence rouge de l'europium vers 1908. Mais cela est entré dans le patrimoine commun. Ensuite quelqu'un faisant une bibliographie à la recherche de ce qui produit une luminescence rouge a trouvé l'europium. Cela s'est passé dans les laboratoires de RCA.
Pour ce qui concerne les labos du CNRS, je peux citer la découverte que j'ai faite avec mon collaborateur Pierre Porcher de la luminescence du prométhium (une terre rare qui n'existe pas dans la nature). C'est une histoire rocambolesque. Le CEA s'est trouvé en possession d'une grande quantité de prométhium récupérée je ne sais pas où. La structure des niveaux d'énergie était connue et il y avait un grand trou qui laissait prévoir une luminescence infrarouge intéressante comme dans le cas du néodyme. D'autant qu'on pouvait espérer faire un laser auto-entretenu car le prométhium est radioactif donc capable de s'auto exciter. On avait un contrat de l'armée pour faire un laser liquide. De l'oxychlorure de phosphore, un mélange hyper toxique dans lequel on a mis du prométhium. On a fait un spectrographe. Au début, on avait bien protégé les côtés mais pas le dessus. La jeune femme qui travaillait sur un appareil à rayons X à l'étage au dessus est venue affolée nous dire que le détecteur marchait tout seul ! C'est dire l'intensité du rayonnement émis par le prométhium ! Mais on a trouvé la luminescence proche infrarouge, très intense. On a essayé de faire la manip laser à Saclay. On a mis le produit dans la cavité on a eu juste eu le temps de voir quelque chose car le rayonnement était si puissant qu'il a détruit les deux miroirs nécessaires pour faire un laser...

BBV : Avez vous jamais songé à prendre des brevets à Bellevue ?

PC : On ne prenait pas de brevets. Qu'est-ce qui se passe quand on est en position de prendre un brevet ? Le CNRS donne à l'inventeur 50% des royalties à condition que quelqu'un achète le brevet. C'est potentiellement intéressant. Mais le brevet met la chose dans le domaine public. Si tu n'as pas une armée d'avocats pour défendre tes droits face aux contrefaçons ce n'est pas la peine. J'avais pris un brevet sur des couches minces de dysprosium métal qui avaient la propriété intéressante de décomposer l'eau et de capturer l'hydrogène. C'était une idée. Mais il valait mieux faire discrètement quelque chose avec Rhône-Poulenc qui donnait des miettes, car c'est toujours mieux que rien.
Le prométhium en revanche n'intéressait que le CEA, mais nous avons publié notre travail et plus tard il a été utilisé par des collègues américains pour des appareils dans des satellites. C'est la seule trace d'une publication qui a servi précisément à quelque chose. On a publié les spectres de dizaines de composés, on a semé. On a proposé des idées. C'est cela la recherche fondamentale.

BBV : Penses-tu que le développement de la chimie des terres rares en France est principalement le fait du CNRS ?

PC : Oui le CNRS et les grands laboratoires universitaires comme ceux de Grenoble et de Lyon, et d'autres, ont fait tout cet effort qui a débouché sur les matériaux luminophores, les aimants, les catalyseurs, etc.

Fin de l'enregistrement

haut de page

accueil du site

Entretien avec Paul Caro, par Bernadette Bensaude-Vincent et José Gomes, 20 juin 2002

Lieu : Académie des Sciences de Paris, France

Support : enregistrement sur cassette

Transcription : Bernadette Bensaude-Vincent.

Édition en ligne : Sophie Jourdin.

ARRIBART Hervé, 2001-02-19, 05-29, 02-20

Sophie Jourdin — 2011-06-16T07:31:17Z

Hervé Arribart is the Scientific Director of Saint-Gobain Recherche, an international company of French origin with an emphasis on glass manufacture. He took his PhD from the Ecole Polytechnique in Paris in the mid-1970s and subsequently researched ionic transport using nuclear magnetic resonance. In the late 1970s he worked with Jean Rouxel's group at the University of Nantes. In 1981 he joined the company Elf to work in research and development. In 1985 he moved to Saint-Gobain, where at first a large portion of his research was closely related to the practical problems of production. In 1990 he started a laboratory (a joint venture of Saint-Gobain and the CNRS) on the basic science of glass surfaces, using a diverse set of tools and especially the Atomic Force Microscope. In 1999 he moved to the more managerial position of Scientific Director. Hervé is also on the staff of this project.

2001-02-19 :

HERVE ARRIBART (HA) : I studied at the École Polytechnique in Paris. The selection to the school is done mainly on mathematics. But during my studies I learnt to appreciate physics in particular. I decided to pursue research in solid-state physics. It was a good place to study physics. While in my last year as an undergraduate I did a Diplome d'Étude Approfondie in parallel (an intermediary between an M.Sc. and a PhD typically done for a year before starting one's PhD studies). In Orsay, near the École Polytechnique, there is a very famous place in solid state physics, a lab started by Jacques Friedel - a great name in solid-state physics. I followed this course and afterwards I did the PhD at the École Polytechnique in the field of condensed matter physics. In principle I ought to have started with a topic distant from materials science. I extracted spin-polarized electrons from semiconductors. This was in 1974.

ARNE HESSENBRUCH (AH) : How did one extract spin-polarized electrons in 1974 ?

HA : It is true of all solids, but in semiconductors it is especially interesting that when light falls upon a surface there is a coupling between the spin of photons (in classical physics : the polarization of light) and the spin of electrons. Electrons in the upper layer absorb light photons depending upon the spin. If by some technique you can extract electrons from the conduction band of the semiconductor, you can find ways to select electrons of specific spins. This was quite important at the time because at big-science institutions such as LEP [Large Electron Positron collider] or SLAC [Stanford Linear Accelerator Center], there was a need for spin-polarized electrons. And of course you then needed solid-state physics to do it. But the man who in principle was my supervisor decided to do something else. His name is Claude Weisbuch, and he is now a good friend of mine. For a few years he was the scientific director of the French Department of Defense. He is still working in solid-state physics, in the optics of semiconductors. But he decided to do something else and Bernard Sapoval, another professor at the lab, proposed that I work on new materials. At that time there was little contact between solid-state physics and solid-state chemistry. The idea was to link up with chemists. This is why very early on in my career I had contact with chemists. We worked with Parisian solid state chemists on a new material. We found a new way to draw single crystals of an already existing material. It was very nice because we could examine transport and NMR phenomena. And the material, a copper vanadium sulfide exhibited astonishing properties : a large spread of conductivity that one can measure in a standard experiment. We suspected that this was due to mixed conduction properties. Mixed conductivity refers to conductivity by both electrons and ions. The experiment appeared to verify our a priori suspicion. This gave me the possibility to present a model for mixed conduction in this material and to understand the influence of ion transport and electron transport. I also used NMR in order to understand which ions moved. It turned out that the copper ions moved. So, this was the subject of my first thesis. At the time, in France, there were two theses. The first one was called "thèse de troisième cycle". The second was the "Docteur es sciences". This degree does not exist any longer. The thesis that is done now is shorter.

I decided to continue to work with chemists. I decided to combine NMR and transport measurements. I changed my collaborators, turning to two different groups. In my PhD there had been two chapters on NMR. But I wanted to study proton transport. I had two reasons. One was that protons give a strong NMR signal. The second reason was that two reasons had been given for proton transport. In one, protons move in individual jumps. In the other the proton is a part of a more complex molecule such as the ammonium ion (NH4+) or hydroxonium (H30+). In the former case we can see the transport phenomenon as a result of molecule rotation and proton jump. The molecule would turn and the proton jumps to the neighboring molecule, which again turns and so on. This was called the rotation-jump model. The second model was for the whole complex ion to jump. This was called the vehicle model because the whole molecule acts as a vehicle. So I worked with one group of chemists in Nantes, at the Institut de Matériaux de l'Université de Nantes. It had just been created by Jean Rouxel, a chemist. With them I worked on a substance called antimony acid - a solid. I was able to show using NMR that transport occurred in this case with rotation-jump. Protons used H30+ as a complex rotator. I was also able to show that the jump was due to quantum mechanics within a certain temperature range. It was not the usual ion transport of classical mechanics.

AH : A tunneling effect ?

HA : Yes, this is one aspect of protons, because protons are very light ions allowing for this quantum effect. The other material I studied was ammonium beta alumina. This was the standard beta aluminium in which the sodium had been ion exchanged with ammonium. This material was very interesting from the perspective of NMR. All kinds of ionic motion took place at different temperatures. At the lowest temperatures, that of liquid helium (1-4K), there was rotational quantum motion. As the temperature increases the motion becomes classical.

AH : If I may make a comparison with Stanley Whittingham here. You were working on some of the same materials, you were using some of the same tools (NMR), but you were asking very different questions, right ?

HA : Yes, that is true. I was not at all involved in the application. For two reasons : French chemists were interested in materials and did not look to the application. And chemists were between me and the application, so I had no contact with attitudes such as Whittingham's. I was very happy working on the solid-state physics problems.

AH : And we are talking about the late 1970s now ?

HA : Yes, I began the proton transport research, I think, in 1976.

AH : And it went on for how long ?

HA : For five or six years.

AH : And you lived in Nantes ?

HA : No, I remained in Paris while collaborating with the Nantes group.

AH : Were you employed in Nantes ?

HA : No, not at all. At the beginning I was employed at the Ecole Polytechnique as a research assistant, and then I was hired by the CNRS - in 1977.

AH : So, the CNRS paid your salary, you were able to do basically whatever you wanted, and you collaborated with Jean Rouxel and coworkers because you found it interesting ?

HA : Yes. It was a chance to work with an outstanding chemist. French chemists were really very good. The problem, as we just said, was that there was little interest in application.

AH : What did you do next ?

HA : After my PhD thesis, I found it interesting to go to industry.

AH : I imagine that there were many advantages and disadvantages to leaving academia for industry. For instance, where was status greater, what paid better, where were working conditions better ?

HA : First of all, it was rare, even more so than today, for CNRS people, or people within the public system, to go to industry. I cannot give you a clear answer about my motivation - it was not even clear to myself at the time. I did get a higher salary in industry. I also had personal reasons for leaving Paris and going to the Elf company. I went to an Elf research lab in the Southwest of France, in a very nice place in the Pyrénées. I had small children at the time and it was much better for them to grow up in the countryside and in a very nice climate. I was also curious. So the decision involved many elements. And anyway, it was not irreversible. The CNRS allowed me to take a three-year leave after which I could have gone back. With regard to the working conditions : I was of course less free than I had been at the CNRS, but I found it more stimulating because there were a lot of different problems on the horizon, arriving almost every day. We could easily get the necessary equipment at the CNRS and at Elf, so there were no differences there.

AH : The restrictions at Elf had to do with what you were allowed to study ?

HA : Yes.

AH : What did Elf want you to do ?

HA : In principle I was hired to work on solid-state sensors. Because it was not in the direct line of my previous work I proposed that I work on solid-state sensors and ion conduction. We developed a family of sensors named ISFETs (Ion Sensitive Field Effect Transistors). It was a new kind of transistor at the time but now it is very common. You control the electrode using field effects, opening and closing the circuit between the two other electrodes. This is the way the transistor works. My idea - not an original one - was to replace this way of controlling the electrode, the gate, to replace it with a membrane, selective to such and such an ion. If you put the device in a solution containing the ion for which you have designed the system, the membrane will be charged. This charge will change the state of the solid-state transistor. It worked all right for protons. We could use the device to measure pH and afterwards we just had to change the nature of the membrane, choosing a different solid electrolyte, such as calcium fluoride.

AH : Your toolkit remained the same and you still used NMR ?

HA : Not NMR, but yes. You need large samples in order to do NMR. So it was mainly electrochemistry and surface analysis. This was between 1982 and 1985. But as I told you, in industry new projects can arrive almost every day. I had developed some skills in electronics using instrumentation at the École Polytechnique. Elf applied for a patent for a medical analysis system, a small instrument to be sold to private practitioners, as opposed to hospitals. This had nothing to do with solid-state ionics. But the people working on this project needed someone who knew about electronics, and so I got progressively more involved. After one or two years it had become my main project. This worked very well. I was very proud to design an electronic system that required no manual setting. It was set in the factory forever. This was a critical issue, because we thought that doctors could not be expected to deal with electronics - and I am sure that we were right in this. So there was nothing to check or calibrate - the system was self-calibrating. So it worked very well, and after only two or three years Elf built a plant and people were hired. But in 1984 and 1985 there were big changes in chemistry. And there was a great redistribution of all chemical industries. And Elf, that had been an oil company, in this period expanded to become also a chemical company. As a result a lot of the more diversified lines of business lost in importance. Many projects like ours were discontinued. But because we were already quite advanced we found a way to keep going. In fact it was Dupont de Nemours that found that our system was complimentary to some of theirs. The result was that Elf shipped the patent and everything else to Dupont. For a few months I considered following the project to Dupont and to the United States. In the end I decided against. I still wanted to work in solid-state physics and not to work completely in the instrument making business. But for one or two years I continued as a consultant.

2000-05-29 :

HA : For both personal and professional reasons, I decided to stay in Paris, and then Saint-Gobain offered me a position, working in a new research field : polymer adhesion on glass and other materials. It was a new topic for me too. At the time adhesion was not even considered a science. It was before Pierre-Gilles de Gennes's Nobel Prize in polymer adhesion [1991]. It was rather considered an art. Even though I had no background in the field I was interested. What interested me in the Saint-Gobain proposal was that real breakthroughs were to be expected in the science of adhesion when two materials are brought into contact. In fact this was my first real industrial experience. Of course CNRS had not been an industrial experience at all, and even at Elf I was always in the research lab. As I explained, my work at Elf had nothing to do with the industrial activities. I never visited factories. At Saint-Gobain I had to do this, at least in the beginning.

AH : Did you not say that your development of the medical analysis system resulted in the setting up of a plant ?

HA : Yes. I did participate in the design of the plan, in order to make it efficient. But I had no role in the plant itself after construction. It was also a small plant for high-tech activity.

AH : You had nothing to do with the fabrication side of it, situated in the plant – merely the R&D before the plant became functional ?

HA : Yes, exactly. Saint-Gobain of course has many plants all over France and Europe, and even the United States. But at that time, the company was still franco-français [French through and through] in its general spirit and culture, despite the many factories in other countries. There were only French directors and the system was based on the French system of education. There is a hierarchy from the École Polytechnique through the École des Mines and the École Centrale to lesser schools, and you carry the status of your school within you for the rest of your life. I remember that I strongly felt the weight of tradition when I first joined the company. It is true that winds of change were already blowing then, but they were barely noticeable and needed a couple of years before really expressing themselves. But eventually the company changed its culture, and now the company considers itself an international one. I think a deep change has taken place during my 15 years with the company.

So, anyway, this was the first time I gained experience of the industrial aspect of research. My first task was to examine and synthesize different kinds of adhesion in Saint-Gobain's products and processes. I decided to simultaneously pursue fundamental reflection and a practical approach, helping the factories improve their processes. This was a very instructive experience. I learnt many things although I am not sure that I helped the factories all that much. I certainly learnt for myself that I preferred to stay within R&D and not to progress into production. On the fundamental side, I developed a network of contacts in public labs in France and the US. This became useful later on. After three years in the field, and having created a small research lab, I decided to gain some distance from the practical aspect of my work. It was also obvious to me that fundamental research was required first. Progressively the idea came to me to propose the creation a special laboratory dedicated to the basic aspects of polymer adhesion - and of course also to related issues such as the surface science of glass. But I knew that Saint-Gobain was not ready to have a laboratory for basic science by itself, so my idea was to set up a lab jointly with the CNRS. This was in 1988. From the administrative point of view this was feasible : a number of such joint ventures already existed, an example of which is Rhône-Poulenc. Of course I had to convince both Saint-Gobain and the CNRS of the utility of the project which was not straightforward. Although I managed to convince Saint-Gobain in a manner of hours, CNRS needed more prompting.

AH : Would you explain the nature of Saint-Gobain's research before your proposed laboratory ?

HA : It was a quite common kind of R&D geared towards problem solving. Helping the development of new products and solving problems within production.

AH : So the research agenda was driven by questions arising out of production ?

HA : Yes, and my idea was to get a more fundamental understanding of the questions which would enable us to help with such questions in a much better way.

Figure 1. Saint-Gobain Recherche, Paris

At Saint-Gobain I had to sell the idea primarily to the Vice-President of R&D. He took the decision just before retiring. The CNRS process was more complex. It has a democratic organization where decisions are taken by committees. The members consist of both elected researchers and individuals named by the Ministry of Research. They are divided up into different scientific sections. So here I had to convince a diverse group of people, and not just one person, as at Saint-Gobain. As I mentioned, I had developed a network of relationships in the fields of adhesion and surface science and now this turned out to be useful. I knew that many people approved of my research agenda. My project was accepted without much fanfare, but it still took a while because of the administrational hoops that a proposal has to jump through within the CNRS. They meet only twice a year, and every decision has to be validated by the CNRS directors and so on. It took maybe 12 months. The laboratory started on January 1, 1990. But there was only a building and neither instruments nor people.

Figure 2. Joint lab : Saint-Gobain Recherche & CNRS

The three yellow arrows point to the units of the joint lab within the Saint-Gobain Recherche building.

In the meantime I conferred with scientists in many other labs trying to recruit people. Of course the CNRS could not order people to go, so I had to entice scientists away. I estimated that I needed three scientists from the CNRS in addition to three scientists from Saint-Gobain. Two of the latter had already worked with me, and they followed me to the new project. A further researcher came from somewhere else – it was a young Chinese woman. We also had two or three technicians and some PhD students. Altogether, it took a year or so to gather everyone together. We also had to buy instruments and the process of getting the laboratory shipshape lasted altogether something like 2 years. We began to actually do some research in late 1990. And from then on the activities progressed rapidly. In two to three years we reached a plateau of 20 people, a level that had been stipulated by the CNRS. A third of the people had come from the CNRS, a third from Saint-Gobain, with PhD students constituting the last third.

AH : Where did they come from ?

HA : The latter were doing industrial PhDs (Contrat à Durée Déterminée) with Saint-Gobain, and their salary came jointly from the French Ministry of Research and from Saint-Gobain. Of the entire staff, about half each came from chemistry and physics. It was crucial that we develop knowledge and expertise in both these fields. Later we also developed an interest in mechanical problems.

Figure 3. The SPM from Park Scientif Instrument

AH : What was the instrumentation ?

HA : There was a conjunction of the beginning of our lab with the very early days of scanning probe microscopy. This new kind of instrumentation offered a very exciting opportunity. There was a risk in this. We purchased the first Atomic Force Microscope (AFM) ever in France. We bought it from Park Scientific Instruments. Later we built the first AFM for UHV purposes. There were many people then who thought the instrument had no future, so it was a risk to invest time and money in it.

AH : Why did people think it had no future ?

HA : The objection was that it was not clear that atomic resolution could actually be achieved with the AFM. It was not until 1993 that Binnig showed true atomic resolution.

AH : Well, yes, but before he had claimed to achieve atomic resolution. In 1993 he only claimed that so far he had been mistaken and only in 1993 did he achieve true resolution. Is that not right ?

HA : Yes. But in 1993 the community was convinced. The reason I did not hesitate was that atomic resolution was not actually the big issue for our purposes. Even a resolution of 1 nanometer amounted to a great deal. Much could be done with such a resolution in the field of adhesion, and also in fracture mechanics and surface chemistry.

AH : I have the impression that since 1995 or so many people argue that atomic resolution is not really that important, and that in the early 1990s it was still considered the holy grail. So you were unusual in that you had this attitude so early ?

HA : You are right that atomic resolution had a special ring to it in those days.

AH : Did you emphasize the issue of atomic resolution in your application to the CNRS ?

HA : I am not sure. Even today, nobody has achieved atomic resolution in glass. So it would have been a hard sell, also then. The same goes for polymers. And those two were our substances under investigation.
There is a difference between STM and AFM. They obey two different logics. The STM has remained a tool of basic research, in surface science. The AFM, even early on (and this would be interesting to discuss with Calvin Quate or Gerd Binnig), there was a hope that it could be useful, for example in other fields of science, such as mine, or in technology, such as process control, microelectronics, semiconductors, and so on. Generally speaking, in early phases there are always many people who think that a novelty will never become common. We have to remember that in 1987 or 1988 solid probe microscopes were still big and unwieldy instruments. Of course miniaturization had set in by 1990, but it was a novelty. Only very few people were convinced that the AFM would become so common. Calvin Quate is one of the few. The STM has revolutionized basic research on metals and semiconductors. There was a reaction against it, because surface science was done using diffraction techniques working in reciprocal space. Surface scientists were formed in this mode of research. They resisted the change, feeling that newcomers would enter their field without the kind of abstraction that had hitherto been key to access to the field. Working in ordinary space was too easy ! Of course it has not actually become easy because the instrument has brought its own problems, and there are still people working with diffraction and in reciprocal space. The two complement each other.

AH : So this is the background against which your decision has to be seen. You went out on a limb.

HA : Yes. The beginning of my lab coincided with the first commercial scanning probe microscopes (SPMs). We had to grasp the opportunity.

AH : How did you know about the AFM ? Was it a very visible instrument at the time ?

HA : No. I knew about it from publications, but in order to actually see an instrument, I had to travel to California - although I guess I could have seen one at IBM Zurich. There was an STM at Marseille, because two physicists there (Salvan and Humbert) had worked at IBM Zurich, and they had brought one back with them. But they had no experience with the AFM. So I went to the US and visited the very few labs with AFM, both academic labs and the start-up companies of PSI [Park Scientific Instruments] and DI [Digital Instruments]. At Stanford University I met Calvin Quate and at UC Santa Barbara I met Paul Hansma.

AH : Was there a relationship between Paul Hansma and DI ?

HA : I don't remember. But at any rate it was not as close as the one between Quate and Park. I think Park was a former student of Quate's.

AH : So you purchased an AFM from Park. What about the other kinds of instrumentation you purchased for your lab ?

HA : Yes, we had to get other instruments, partly because it took a long time for the AFM to arrive. I had to go to the US to compare the DI and the Park instruments, and I discussed it with the physicists and chemists in our lab before ordering, and then we had to wait for the delivery – maybe 4 months or so. We got a 40% discount, because we were the first French customers, and they hoped that we would open the French market for them. I had very good discussions with Quate, and I think he trusted me to be a good advertisement for him in France. I think we paid 400,000 French Francs, so that the catalogue price was in the order of 800,000 French Francs [approximately US$100,000].

We bought also an infra-red spectrometer, in order to study molecular grafting on oxides. This we used as a complement to the AFM. And as I said in a previous part of the interview, our approach was to combine the traditional surface science (very clean surfaces) with “true surfaces” interacting with the environment. The infra-red spectrometer, XPS (X-ray Photoelectron Spectroscopy), and LEED (Low-Energy Electron Diffraction) were good tools for the traditional surface science approach working in UHV Ultra-High Vacuum). And also HR-EELS (High-Resolution Electron Energy Loss Spectroscopy). Our choice was risky, but it turned out to be correct. Our decision to build bridges between the two approaches was taken in 1992 or 1993. Quite early on in our project we built a surface force apparatus (SFA). It is not at all an AFM – there is no concept of high resolution, but it is similar in that you can get a direct measurement of the force interacting between two objects only a few Ångstroms apart. The idea is to make the measurement quantitative in order to study whether the interaction is due to van der Waals or electrostatic forces. In fact this project took six years – not for technical reasons but simply because we had to get the right people.

AH : Each instrument had its strengths and weaknesses in terms of resolution and the scale of the surface analyzed. And each instrument required special skills. The AFM, for example, requires quite some expertise to disentangle signal from instrumental artifacts, right ?

HA : Yes, artefacts were a real concern at the beginning, when we all had very limited experience. We had to pay much attention in order to ascertain the results.

AH : Can you explain how one separates signal from artefact ?

HA : There are different kinds of artefact. One that now seems quite natural but was hard to understand then is the tip effect. If the surface under examination has sharper topographic features than the tip, then the tip will be imaged rather than the surface. We had trouble with this kind of artefact. In fact, when studying tin oxide deposits on some substrate we got very nice images that we at first interpreted as small crystals having the similar orientation. We were very excited to find a growth mechanism of specific orientations on isotropic surfaces such as glass. I decided to present this result at a small meeting in Davos, Switzerland. The topic there was in fact “The AFM for Technological Applications”. Famous scientists attended, including Calvin Quate, Jim Gimzewski, and Heinrich Rohrer. There were only some 10 people there, because this was very early, maybe 1991. The night before my presentation, I began to wonder that the result was really too beautiful to be true. I telephoned my lab and asked people there to turn the sample by some angle and do the experiment again. That way, the features should have changed if they belonged to the surface. But they did not, and so we knew that the features belonged to the tip. So I did not present that particular slide in my talk.

AH : So rotating the sample by some degree is one way of identifying artefacts.

HA : Yes, that will eliminate this kind of artefact, the tip effect. There are also adhesion artefacts, some of which have been solved in the meantime thanks to new recording techniques such as the tapping mode.

AH : Digital Instruments has a patent for the tapping mode, right ?

HA : Yes.

AH : So the Park instrument that you bought did not have the tapping mode ?

HA : No it did not. The tapping mode did not become available until 1993 or so. Later on, Park Scientific Instruments did do something similar, but they may not call it tapping mode. The DI patent covers the name. And in the straightforward contact mode many artefacts were possible ; for example when looking at soft materials and polymers surface scratches easily occur. If you do that you image the substrate only. One way to identify this effect is to scan again with a smaller tip-surface interaction. In some cases you will find miniature small squares where the surface had been damaged in the course of the first scan. Some artefacts are very common, others are quite specific and harder to identify.

AH : In what you have explained, the identification of artefacts is internal to the instrument itself. It is not that you can go and compare the results of an AFM scan with those from a different instrument ?

HA : You can change the tip, and you should identify artefacts unless you are very unlucky to get the same tip. Everybody understood that the AFM has great potential not just as an imaging instrument but also to measure adhesion, hardness and so on.

AH : Using force-distance curves ?

HA : Yes, force-distance curves. This turned out to be very useful for us. For instance in order to understand the electrostatic interaction between oxide and a silicon nitride tip under water. This was original work. For example, in polymer adhesion we checked if it stayed on the substrate and what scratching would do. Of course such ideas were floating around at the time.

AH : Were you important to the subsequent spread of the AFM in France ?

HA : Yes, people came to our lab. Another lab, at the Institut Curie, that got an AFM at almost the same time. For a while we were a small community but then gradually we grew larger and larger. Yes, we were the pioneers. It was exciting.

2001-02-20 :

HA : I went with one of my sons who was 11 years old at the time to see Park Scientific Instruments. There were no more than 10 people working there, in fact I think it was more like three. It was very small and familial. We discussed and had tea. I enjoyed discussing with these people. It was nothing like an established company.

AH : What did it look like ? Did they work out of a garage ?

HA : Something like between a home and a garage. It was a small house. Even Digital Instruments started out like this. Already in those days DI, and especially Virgil Elings, was much more commercially aggressive, but they were very small too at the time.

AH : Did you stay in touch with some of these guys ?

HA : I stayed in touch with Calvin Quate for five or six years, until 1996. After that I lost the contact but he will probably remember me because we had many discussions. It was curious to see his impact upon materials science. In fact it was very difficult for him to get the first paper on the AFM accepted in Physical Review Letters. Some of it was considered just a pure mechanical profilometer. It had good resolution but it was not really anything new. His project now is very interesting from what I can tell reading his articles in the scientific journals. And he really is a very nice person. Maybe the last time I saw him is when I invited him to give a talk at Saint-Gobain Recherche.

AH : So you stayed in touch with him in the early 1990s, while you were developing your own AFM. I guess the use of the AFM changed the project from what you had originally envisaged ? Did you continue using all the other tools or did you focus exclusively on the AFM ?

HA : We used the other tools.

AH : What did you buy for your laboratory ?

HA : Infrared spectrometer, XPS, HR-EELS (High Resolution Electron Energy Loss Spectrometer), LEED. Quite quickly we had three AFMs. I wanted to develop a PSTM working in the infrared but unfortunately that particular project died because the physicist we had working on it left.

AH : What journals show the history of these instruments best ?

HA : In the beginning it was mainly in the general physics journals such as Applied Physics, Applied Physics Letters, Physical Review Letters, Surface Science. Now there are specialized journals. A journal like Journal of Scientific Instruments is not so important in this respect. Langmuir is also important for soft matter.

AH : Do any of these journals have review articles ?

HA : I am almost sure that all of them do.

AH : We were talking about the various instruments you had in your lab. How did you apply them to your research project ?

HA : The idea was to have two parallel approaches. We were mainly interested in adhesion, molecular grafting and so on. One approach is the classical view of surface science, the ideal surface approach. The other is the REAL surface approach, taking the environment as a part of the system.

AH : Not working in Ultra-High Vacuum (UHV) ?

HA : Yes. But we were trying to make the two approaches meet.

AH : So when you started working with the AFM in UHV, the point was to simplify the experiment ?

HA : Yes.

Figure 4. UHV Chamber et AFM in UHV Chamber

If a probe were to be introduced directly into the UHV chamber, it would take days of pumping to achieve UHV. Instead, it is first introduced into an antechamber, whereupon a vacuum is produced there. Only then can walls be opened without reducing the UHV too much. By pushing the rods labelled 1 and 2, the sample is transported in successive stages into the central chamber. Several instruments are attached to the chamber, including an XPS. On the right, an AFM can be discerned in the UHV chamber.

AH : How did the various instruments complement each other ?

HA : The spectrometers provided structural information. They give a chemical signature. One point of interest was silver on magnesium oxide. In order to have a simple model of glass we chose to study this problem within pure single crystal. We had the probe in situ in the same UHV chamber where we had the instruments to add the deposition techniques. In the case of silver it was just thermal evaporation. We wanted in situ real-time studies of the atoms arriving upon the substrate, the oxide surface. There were two models in this problem. One was that the atoms remain isolated or form small islands, so that the growth process is two-dimensional, so that you first get a perfect monolayer before a second layer is started upon. The other is that growth is three-dimensional with occasional collapses into flatness. To study this it is of course useful both to look directly and to use diffraction techniques. But in order to understand the process you need to grasp the interaction between the silver and the oxide. And only spectroscopic techniques will help here. We always tried to look at a problem from two differing points of view – in this case geometrical and chemical.

AH : You make it sound easy. You just use one tool and you get the topography, and then you use another and you get the chemical composition.

HA : Well of course it is not at all easy. It was very difficult because for instance, the STM works very well when you have a smooth surface but when you have corrugation it becomes much more difficult, because this corrugation interferes with the instrument. In spectroscopy you integrate over the size of the beam which is much larger than the surface scanned by the AFM. So you have to do many different experiments to see what effect the temperature has and so on. You also have to model the interaction. This was a little known problem. What is the mechanism of very small silver clusters on magnesium oxide with other silver clusters in the neighborhood ? It was a new problem. So it took time to understand the system.

AH : What is the measure of success ? It was partly CNRS, so you were under pressure to publish ?

HA : Yes.

AH : And since it was partly Saint-Gobain you had to get patents ?

HA : We had to do both. It was an interesting exercise in communication. In my position as head of the lab, I could not use the same words, the same way of presenting things when addressing different audiences. From time to time it was necessary to gather the scientific and the industrial people together under one roof.

AH : And what language did you speak then ?

HA : Fortunately everyone was happy with this lab, so it was not quite so difficult. The conditions were good. Nonetheless your question is quite correct. It was interesting.

AH : How did you convince Saint-Gobain that this would have a pay-off ? And how did you negotiate long- and short-term goals ?

HA : The short term was a problem. It was not straightforward to plan a new product for the company. The pay-off was very diffuse and difficult to identify. One way of motivating the directors was the argument that we trained very good PhD researchers for Saint-Gobain. And this was not expensive for Saint-Gobain, because they shared all the expenses with CNRS. Up until now this has not been a problem.

AH : Stanley Whittingham told me that in the last 15 years or so there has been a tremendous shift in company planning towards the short term in industry. Partly this was due to the MBA education and the fanning out of this new generation of business administrators into all nooks and crannies of industry. As a result the long-term disappeared, because everything had to fit into the financial year so that you have something to show to your shareholders.

HA : It is true that this has taken hold in industry. We had the good fortune that it was not very developed in Saint-Gobain. But also, the time required for the development of new glass materials just is acknowledged to be greater than that in electronics or informatics. When we start new projects, we are simply not able to show a product six months later. So we are less exposed than people in other fields, but the general development that you alluded to certainly has taken place. Maybe our situation will also change in the future. We may be excessive.

AH : Has the accountancy changed for you ? Did you have to write annual reports ? And has it changed over the last ten years ?

HA : In general ?

AH : Well, for the CNRS I can sort of imagine it. In academia you would specify the number of publications that you have produced and that is the measure. End of story. And that is very simple accountancy. But if you account to a company, keeping in mind the increasing influence of MBAs : did you have to account for your expenses in ever greater detail ?

HA : I do not think there has been such a change in the last decade.

AH : And do you write annual reports ?

HA : Bi-annual. But I am not in this lab anymore ; I left two years ago.

AH : Okay, so during the 1990s up until two years ago you wrote biannual reports to the company and in that period the structure of the reports did not change.

HA : That is correct.

AH : Did you have to specify just how much money you spent ?

HA : Yes, but also there, no change took place. And I always reported to the same person within Saint-Gobain. He was basically content with what we did, so it was never critical. It is true, it might have changed with a different person in charge.

AH : So, how did the instrumentation change throughout the 1990s ? The AFM became commercially available to an ever greater extent, you were able to buy many more things off the shelf. Is that true also of all the other instruments ?

HA : Yes, there are different aspects to your question. We used to build many instruments ourselves, and this was of great use for training. And this has changed. A reason the French PhD has been shortened is that equipment is being bought and not made in-house. That is a general trend. Science is changing as a result, because using a commercial instrument is not the same. When you develop an instrument yourself you know exactly how to get the result. In the specific case of AFM/STM : probably the AFM has been developed much more than the STM. In the STM the major breakthrough was with the driver and that was quite early. I think it was possible to purchase an STM driver already by 1992. Variable temperature was a little more difficult, but it was certainly available by 1994. Different ways of scanning and acquiring information were developed. Otherwise the evolution was purely technical : cheaper, and more diverse (such as an STM expressly for electrochemical research). By contrast the AFM has developed rapidly. Tapping mode and other modes where you measure not only the distance but also hardness, conductivity, adhesion, chemistry. It has become possible to map all these parameters. This explains why more and more people use the AFM.

AH : It has also become cheaper, right ?

HA : Yes.

AH : It has certainly become more user-friendly, adaptable to different circumstances.

HA : Yes. For the STM : there have very beautiful studies made of the coupling between tunneling and modulation. You might modulate the tunneling current with light for instance. You can even leverage the spin of the tunneling electrons. So you can do beautiful physics. But this contributes little to the democratization of the technique.

AH : I have the sense that Calvin Quate, by contrast, is working hard to increase throughput.

HA : Yes, that is right. There can be two reasons for doing that. To make the investigated part of the surface larger – of use in the semiconductor industry. And to shorten the time required for a scan. He is trying to use the system technologically.

AH : Okay. Two years ago you left your lab. Your own lab. Why ?

HA : I wanted to try something new and I was lucky to find someone who was well capable of taking over and for whom I have a lot of respect. He is from a different background. So now it is a different group. I became the Scientific Director of Saint-Gobain Recherche. There are two parts to the job ; one is to be the scientific manager, the other is to establish contacts in the outside world, and to promote innovations within the company, for instance with the marketing people.

AH : You were promoted ?

HA : Yes.

AH : And you have become slightly removed from lab work ?

HA : Yes, completely, I am now involved in organizational work.

AH : In fact, our project resembles your job in the sense that we stand back and look at the scientific research and try to gain a perspective ?

HA : Yes, you could say that.

Fin de l'enregistrement

Pour citer l'entretien :

« Entretien avec Hervé Arribart », par Arne Hessenbruch, 19 février, 29 mai et 20 février 2001, Sciences : histoire orale, /spip.php ?article47.

Pour citer l'entretien :

« Entretien avec Hervé Arribart », par Arne Hessenbruch, 19 février, 29 mai et 20 février 2001, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article47.

Lieu : dans le salon (les 19 février et 29 mai 2001) et dans la petite salle de réunion (le 20 février 2001) du Dibner Institute, Etats-Unis.

Support : enregistrement sur cassette.

Transcription : Arne Hessenbruch.

Édition en ligne : Sophie Jourdin, Sacha Loeve.

MONDANGE Hélène, 2004-12-04

2010-02-18T09:21:38Z

Hélène Mondange, née en 1925, est chimiste. Diplômée de l'École nationale supérieure de chimie de Nancy (ENSIC) en 1948, elle rejoint le Centre d'études de chimie métallurgique (CECM), dirigé par Georges Chaudron, pour y commencer une thèse sur les oxydes de fer. Confrontée à diverses difficultés, en particulier celle d'être une femme dans un laboratoire de recherche des années 1950, elle ne soutiendra sa thèse que dix ans plus tard, en 1958, sur les phases cristallines de l'aragonite. Elle travaille dans l'ombre de Chaudron, l'aidant par exemple à la rédaction des chapitres du Pascal [1] qu'il signe. En 1967, elle rejoint Jacques Bénard au Laboratoire de physico-chimie des surfaces des solides de Chimie Paris, où elle enseignera avec enthousiasme et poursuivra ses recherches de chimie du solide jusqu'à la fin de sa carrière en 1983.


Autorisation de diffusion

PIERRE TEISSIER (PT) : Pouvez-vous me raconter votre formation ?

HÉLÈNE MONDANGE (HM) : Je suis née Hélène Dufy, dans le Charolais, où j'ai fait mes études durant la Seconde Guerre mondiale. En 1940, j'étais boursière en École primaire supérieure (EPS). Mes parents étaient paysans, je ne pouvais pas aller au lycée et je voulais devenir institutrice. L'EPS préparait aux Écoles normales d'institutrices qui permettaient d'enseigner dans les écoles primaires. Quand Pétain est arrivé au pouvoir, il a supprimé le système EPS comme étant subversif : tout le monde devait aller au lycée. Après la période de débâcle, mes parents ne voulaient pas que j'aille en pension au lycée. Je suis restée quelques mois en inactivité forcée. Puis une de mes enseignantes d'EPS est venue dire à mes parents que je devais aller au lycée. En janvier 1941, je suis donc entrée au lycée, mais en seconde car il était trop tard pour passer en première. En 1943, j'ai eu mon baccalauréat. Ensuite, j'ai fait deux années de « taupe » pour rentrer à l'École normale supérieure de Sèvres, alors équivalente pour les filles à l'ENS de la rue d'Ulm réservée aux garçons. J'ai été parmi les premières recalées au concours et je suis devenue « boursière de licence » : les premiers recalés des concours aux Écoles normales recevaient une bourse s'ils acceptaient de poursuivre leurs études hors de Paris. Il s'est trouvé que l'École de chimie de Nancy [future ENSIC] acceptait les boursières de licence car les concours pour les ENS et l'ENSIC tombaient le même jour. Je suis donc allée là-bas : nous n'étions que deux filles – toutes deux entrées comme boursières de licence –, sur une grosse promotion de cinquante-cinq étudiants. Je dis « grosse » parce que c'était le moment où les jeunes gens revenant de la guerre ou du STO [service du travail obligatoire] réintégraient le cycle universitaire. Les promotions précédentes comptaient plutôt quarante-cinq élèves. Les filles ne se présentaient pas beaucoup au concours d'entrée. Je suis donc restée à Nancy de 1945 à 1948. À l'époque, il y avait encore des cartes de rationnement en pain. L'ambiance à l'École était bonne entre les élèves : nous faisions une fois par mois des réunions entre promotions. Les garçons nous vouvoyaient mais se tutoyaient entre eux ; nous nous appelions par le nom de famille et pas par le prénom.

PT : C'est là-bas que vous avez connu Robert Collongues ?

HM : Oui, il était de la promotion qui me précédait avec Fernand Coussemant. C'était une promotion sans fille. Coussemant a longtemps travaillé à l'Institut français du pétrole (IFP) puis a été directeur de l'École nationale supérieure de chimie de Paris (ENSCP). Il a beaucoup travaillé avec Balaceanu qui fut directeur de l'IFP.

PT : Comment êtes-vous venue travailler avec Georges Chaudron à Vitry-sur-Seine ?

HM : Chaudron était un homme original, il voulait avoir des étudiants d'un peu partout. Il avait été directeur de l'Institut de chimie de Lille. Ensuite, juste avant la guerre, il a été nommé directeur du Centre d'études de chimie métallurgique (CECM) à Vitry. Ses élèves venaient d'horizons différents : Montuelle et Talbot étaient de l'Université de Lille, Montel de Chimie Paris, Fayard était normalien, il y avait un polytechnicien, un centralien, un Roumain, un Polonais... (Figure 1)

Figure 1 : Hélène Mondange et ses collègues du CECM

De gauche à droite : Gérard Montel, Hélène, H. Massiot, Aurel Berghezan. Avec l'aimable permission d'Hélène Mondange.

Chaudron avait proposé une thèse financée par le CNRS aux étudiants de la promotion qui me précédait. Collongues a accepté la proposition et a été retenu. Il est donc venu au CECM, alors dirigé par Chaudron à Vitry. L'année suivante, Chaudron a de nouveau proposé une bourse de thèse à Nancy. Cette année-là, il n'y eut qu'une fille qui accepta : c'était moi. Il n'était pas très disposé à accueillir une fille dans son laboratoire. J'ai su après coup que Chaudron avait demandé à Collongues quel genre de fille j'étais, si « je me peignais le visage » ! Il m'a vue au cours d'un entretien et ensuite il m'a engagée. Je ne savais pas que c'était le Chaudron des diagrammes des oxydes de fer – réduction du minerai dans les hauts fourneaux –, celui dont on nous avait parlé en « taupe », sinon j'aurais été beaucoup plus impressionnée.

PT : Ensuite vous avez commencé votre thèse à Vitry ?

HM : Je n'avais pas très envie d'aller à Vitry : je m'étais mariée et mon mari travaillait à Paris. Nous n'avions trouvé qu'une maison à Colombes, c'était difficile de se loger à Paris à l'époque. De Vitry à Colombes, il fallait près d'une heure et demie de transport. Pourtant je n'ai pas eu trop le choix, j'ai commencé ma thèse en septembre 1948 au CECM, j'étudiais alors les oxydes de fer. Ce qui est étrange, c'est qu'au début Chaudron ne m'a jamais directement demandé ce que je faisais au niveau scientifique ; il passait toujours par l'intermédiaire de Collongues pour connaître l'avancement de mon travail. J'étais dans le même bureau que Talbot et Collongues. Je me suis arrêtée en novembre 1949 pour mon premier enfant. Après ma maternité, je ne voulais plus être chercheuse, c'est dur quand on a un enfant et puis j'étais toujours plus attirée par l'enseignement : je voulais passer l'agrégation. Chaudron m'a dit qu'il ne fallait pas que je m'embête avec l'agrégation, que j'allais d'abord finir ma thèse en deux ans. Elle a encore duré huit ans ! Je pense qu'il était très intéressé par ce que j'avais commencé sur les oxydes de fer, entre-temps Collongues avait repris mon sujet. À Pâques 1950, quand je suis revenue, j'ai accepté de travailler avec Chaudron mais à l'ENSCP où il était devenu directeur. Paris, c'était beaucoup plus pratique pour moi, mais je travaillais seule !

PT : Vous avez perdu contact avec les autres du CECM ?

HM : Non, j'allais à Vitry de temps en temps, quelques fois par an. Je retournais voir Collongues et Talbot. Ils n'étaient pas plus d'une quinzaine à l'époque au CECM. Si l'on regarde cette photo de juillet 1949 (Figure 2), on compte treize personnes sans Chaudron : Aurel Berghezan, un Roumain qui est devenu professeur en Belgique, Jean Duflot (École centrale de Paris), Philippe Albert, Jean Talbot, M. Mouflard, Robert Collongues, Matei Pruna, Gérard Montel, Novak, un Polonais…

Figure 2 : La joyeuse équipe du CECM à la veille des vacances, juillet 1949.

de gauche à droite : Philippe Albert, Jean Talbot, Hélène Mondange, Robert Collongues, Matei Pruna, Jean Duflot, Gérard Montel, Mademoiselle Mouflard, Aurel Berghezan. Avec l'aimable permission d'Hélène Mondange.

J'étais alors la seule fille à préparer une thèse. Il y avait aussi une secrétaire, « Mademoiselle Billot », et une technicienne, Annie Binet, qui deviendra madame Duflot et travaillait avec Albert : elle dosait l'hydrogène, je crois, et, pour le recueillir, elle devait travailler longtemps sur un bain de mercure, ce qui préoccupait beaucoup Chaudron. Nous avions également un atelier dont les ouvriers étaient étroitement associés aux chercheurs. Il y avait parmi eux un souffleur de verre. Il y avait une très bonne ambiance dans ce labo, on était content d'être au laboratoire de « Monsieur Chaudron », les gens se serraient vraiment les coudes. Talbot jouait au football, je me rappelle, il était au PUC [Paris université club] et ça ne plaisait pas à Chaudron. Pendant les trois premiers mois où j'étais là, il n'y avait pas de cantine et chacun apportait sa gamelle. Ensuite, on s'est organisé : Duflot, qui était parisien, achetait aux Halles des sacs de patates et les ramenait au laboratoire où la femme de ménage avait accepté de faire des frites ou des pommes de terre bouillies. On avait un plat chaud et on mangeait tous ensemble. Il y avait aussi deux anciens du laboratoire Le Chatelier, des anciens camarades de Chaudron, qui avaient été ruinés par la guerre et qui venaient rendre des petits services : "le père Vial", qui aidait aux travaux pratiques de chimie appliquée et "le père Bossuet" qui exécutait les photographies et racontait des anecdotes sur le laboratoire Le Chatelier ("le thé du samedi après-midi" quand les petites repasseuses venaient apporter les blouses propres).

PT : Vous avez changé de sujet à votre retour ?

HM : En fait, j'ai passé un an à attendre un nouveau sujet de thèse en 1950 : Chaudron était très occupé. Quand Pruna a présenté sa thèse sur les carbonates en 1951, j'ai finalement repris son sujet. Deux points intéressaient Chaudron : la période d'incubation pour faire une comparaison avec l'acier ; et le frittage que j'étudiais principalement par dilatométrie. J'ai terminé ma thèse en 1958, soit près dix ans après le début ! Durant toute cette période j'ai été attachée de recherche au CNRS. En 1958, je me rappelle que l'un des étudiants m'a dit que j'étais la première fille à présenter une thèse sous la direction de Chaudron : j'étais très fière car c'était difficile pour les filles à cette époque, nous n'étions pas prises au sérieux !

PT : Comment Chaudron organisait-il la recherche dans son laboratoire ?

HM : Il y avait trois ou quatre équipes, on disait des "services", qui travaillaient sur des thèmes différents. Chaudron pensait que toutes les méthodes de chimie minérale pouvaient être appliquées aux métaux. Il y avait même une formule qu'il avait fait imprimer sur les chemises du CECM : « Dans un établissement de recherches, tout progrès dans un certain domaine doit être appliqué aussitôt dans les divers champs auxquels l'établissement s'intéresse. » Albert dirigeait le service de purification des métaux, Talbot étudiait la diffusion de l'hydrogène dans le palladium, il y avait aussi une équipe de chimie minérale, dirigée par M. Faivre, qui travaillait sur les phosphates et les carbonates.… En revanche, à l'ENSCP, il n'y avait pas encore de laboratoires de recherche, je crois que c'est Chaudron qui, en tant que directeur de l'École, y a insufflé la recherche. Je devais aller au CECM pour faire des observations de microscopie électronique. Je me rappelle qu'il existait un film tourné au temps de la thèse d'Albert. Il travaillait sur le dosage des impuretés par radioactivation et collaborait avec Irène Joliot-Curie (1897-1956). En fait, il avait surtout des rapports avec un jeune et brillant élève d'Irène qui s'appelait Pierre Sue. Il est mort très jeune. Le laboratoire d'analyse par radioactivation, créé à Orléans et dirigé par Albert, porte son nom.

PT : Quels ont été les successeurs de Chaudron à la tête du CECM ?

HM : Après le départ de Chaudron, il y a eu son élève, André Michel, complètement dévoué au patron, presque soumis, qui lui laissait encore prendre toutes les décisions. Puis vint Michel Fayard, un autre élève de Chaudron et ensuite Jean-Pierre Chevalier.

PT : À quelle époque est apparue la chimie du solide ?

HM : C'est Chaudron qui a initié la chimie du solide tout en se passionnant pour les métaux purs. Il avait été emballé par la fusion de zone développée par [William] Pfann. C'était le début des semi-conducteurs. Je me rappelle une conférence donnée par Aigrain au Laboratoire de chimie physique dans les années cinquante sur le « dopage » du silicium et du germanium préparés par fusion de zone. C'est Chaudron qui, avec ses élèves de Vitry, a commencé à purifier l'aluminium (le plus facile), puis le cuivre (par Le Héricy), le fer, le zirconium (par Langeron). On purifiait le fer jusqu'à des limites telles qu'il devenait très conducteur, mais ça n'a jamais été possible de transposer cette méthode au niveau industriel car ça coûtait trop cher. À ce propos, Chaudron et ses élèves ont écrit un excellent livre sur les métaux purs [Monographies sur les métaux de haute pureté].

PT : Comment situer la thèse de Collongues par rapport à cela ?

HM : C'est une thèse remarquable. Il y a un parallèle entre la décomposition du protoxyde de fer et l'eutectoïde fer-carbone, c'est-à-dire l'acier. Collongues m'avait dit qu'il y avait de nombreux points qu'il n'avait pas vus lors de la rédaction de sa thèse et que Chaudron les lui avait montrés. On peut dire que le travail d'interprétation de la thèse de Collongues est dû en partie à Chaudron.

PT : Qu'avez-vous fait après votre thèse ?

HM : Chaudron m'a demandé d'aller travailler à Vitry dans l'équipe Collongues mais celui-ci n'a jamais été mon patron. Je suis arrivée à l'automne 1958, en même temps qu'Anne-Marie Lejus, qui était une fille super. J'ai travaillé avec Monique Perez y Jorba sur les oxydes de titane. Je l'avais connue comme élève aux travaux dirigés de chimie appliquée de la Sorbonne qui se faisaient à l'ENSCP. Nous travaillions sur la co-précipitation des oxydes mixtes. À cette époque, il y avait aussi Jean Lefèvre, François Leprince-Ringuet…

PT : Vous êtes restée longtemps dans le service Collongues ?

HM : Un peu moins de deux ans, jusqu'en 1960. Ensuite j'ai été rattachée à Chaudron, à l'ENSCP comme maître-assistant. En fait, il avait besoin de quelqu'un pour l'aider sur le « Pascal ». C'est un ouvrage encyclopédique entrepris par Paul Pascal sur tous les éléments de la chimie minérale. Chaudron a été chargé d'écrire le chapitre sur le fer mais comme il était très occupé alors, il m'a demandé de coopérer avec lui. Comme je lui faisais remarquer qu'un maître-assistant devait faire de la recherche, il m'avait rétorqué que la recherche bibliographique était aussi de la recherche. Nous avions fait un pacte : il me donnait le jeudi, jour de congé des enfants, et je venais travailler le samedi. Le samedi matin, il recevait parfois Irène Joliot-Curie, parfois il n'avait pas le temps de me voir le matin et il m'emmenait chez lui pour le déjeuner. Madame Chaudron n'était pas toujours ravie de me voir arriver. Je m'occupais aussi de l'enseignement de métallurgie alors que je n'en avais jamais vraiment fait. Mais ce fut très intéressant de préparer ces travaux dirigés : la métallurgie associe la chimie, la cristallographie, la thermodynamique et la physique. Pendant ma thèse, j'étais aussi monitrice pour les travaux pratiques de chimie appliquée. Puis après ma thèse, j'aidais les étudiants de DEA à préparer les exposés du séminaire de métallurgie. Mon sujet de seconde thèse avait porté sur les dislocations : à cette époque, la thèse d'État devait être accompagnée d'une deuxième thèse qui était uniquement un travail bibliographique. Chaudron a mis très longtemps à croire aux dislocations (défauts à deux dimensions dans les cristaux) : il m'avait donc fait refaire des expériences de « microscopie sur fond noir » (dans un solvant de même indice optique que le solide) pour mettre en évidence certains défauts qui apparaissaient brillants sur fond noir.

PT : Vous étiez amenée à fréquenter beaucoup Chaudron ?

HM : Oui. Je peux dire qu'il était très paternaliste, dans le bon et le mauvais sens du terme. Il était très attaché à ses étudiants pour les questions scientifiques mais aussi pour les problèmes plus personnels. Le mariage d'un de ses jeunes chercheurs l'inquiétait toujours : « Est-ce que la jeune épouse comprendrait les exigences de la science ? ». C'était l'époque où Albert et les gens de son équipe se relayaient pour passer les nuits à surveiller la « zone fondue » : lent déplacement d'un barreau de métal dans un four pour fondre une étroite zone liquide qui « balayait » les impuretés du métal en tête ou en queue du barreau. Je me souviens de madame Jeanin qui faisait l'étonnement d'Albert : "elle travaille comme un homme !". C'était dans les années 1950. Je me rappelle qu'au cours de la journée du samedi, il lui arrivait de me raconter les "histoires de brigands" comme il disait, les potins de ses élèves. Pour la rédaction des thèses, il invitait même ses étudiants à passer quelques jours pendant les vacances d'été dans sa maison, à Étretat.

PT : C'était une sommité à l'époque ?

HM : Oui, on m'a même dit qu'il a été pressenti à un moment pour le prix Nobel pour les métaux qu'il avait purifiés. Aux Journées d'automne de la métallurgie, congrès international très couru, il était parmi les plus écoutés. Dans les années 50, à l'occasion de l'un de ces congrès, je me rappelle son opposition à Bastien, professeur de métallurgie à l'École centrale de Paris, à propos de la diffusion de l'hydrogène dans le fer. C'était un problème technique au départ : au moment de la Deuxième Guerre mondiale, les coques de bateaux américains en acier avaient été coupées en deux en naviguant dans des eaux froides. C'est le passage d'une rupture ductile à une rupture fragile à basse température qui explique cela. L'hydrogène qui se trouvait dans l'acier au niveau des fissures diffusait alors rapidement en diminuant la tension superficielle. L'hydrogène pénètre dans l'acier au moment de la soudure, l'eau vapeur dans l'air autour du chalumeau est ionisée et les protons pénètrent alors dans le métal. En protégeant les soudures de l'air ambiant le problème avait été résolu techniquement mais le débat entre les deux professeurs portait sur la compréhension du phénomène. C'est Dadian qui a fait sa thèse avec Chaudron sur ce sujet. Dans ce genre de colloque, Chaudron avait tendance à s'assoupir après le repas. Dans ces moments-là, nous craignions de n'avoir personne pour défendre « notre école » face à Bastien. En fait, comme souvent, il écoutait encore d'une oreille et participait vivement au débat engagé.

PT : Est-ce que Chaudron était intéressé par la physique ?

HM : Chaudron était avant tout un homme de paillasse ; la chimie théorique n'était pas son affaire ; il voulait que les expériences soient reproductibles mais ne s'intéressait pas à la théorie. Je me souviens d'une conférence de Nevill Mott, un théoricien anglais, au Laboratoire de chimie physique. Mott se servait de nos résultats pour justifier ses théories et ça semblait déplaire à Chaudron. Je ne sais pas si Chaudron ne voulait pas qu'un théoricien exploite son travail ou s'il voulait simplement être cité, ce que Mott n'avait pas fait. Quoiqu'il en soit, il trouvait les théories peu intéressantes, fumeuses même, il n'aimait pas trop les calculs. En revanche, les manipulations, les expériences, les instruments, il aimait beaucoup.

PT : Qu'était le Laboratoire de chimie physique ?

HM : C'est un laboratoire à côté de l'École de chimie, qui était dirigée par mademoiselle Yvette Cauchois. Celle-ci était une femme extraordinaire, elle avait travaillé sur les rayons X. C'était une femme qui m'impressionnait beaucoup et que j'admirais. Elle a pris sa retraite en décembre 1978. C'est un laboratoire qui est rattaché à l'Université de Paris comme l'Institut Poincaré, l'Institut Curie ou l'École de chimie.

PT : Quelle a été la suite de votre carrière ?

HM : À partir de Pâques 1967 et jusqu'à ma retraite en 1983, j'ai été affectée au laboratoire Bénard, Laboratoire de physico-chimie des surfaces des solides, à l'ENSCP. Bénard était très différent de son maître Chaudron, il n'était pas paternaliste du tout. Alors que j'étais encore avec Chaudron et que je le croisais dans les couloirs de l'École, il me paraissait glacial. J'étais chargée de la régie du laboratoire et d'un enseignement. J'étais très proche des étudiants qui venaient me faire signer les papiers et que je voyais très souvent lors des travaux pratiques et de la préparation des séminaires. À ce moment-là, j'ai beaucoup apprécié Bénard, il était extrêmement intéressant. J'aimais discuter de recherche avec lui, ce que je n'ai jamais pu faire avec Collongues, je ne sais pas pourquoi. Nous étions sans doute trop proches comme anciens de Nancy : quand je voulais parler science, il commençait toujours à plaisanter et c'était fini. Je trouvais qu'il était opportuniste mais c'est bien la seule chose que je puisse lui reprocher, il était diplomate. En tant qu'enseignant, il était excellent, comme Bénard d'ailleurs. J'ai assisté à ses cours car j'aimais savoir ce que le professeur disait quand j'étais chargée de TD. Il parlait très facilement, avait toujours une histoire amusante à raconter. Ses élèves l'aimaient beaucoup, lui étaient très dévoués. Je crois aussi qu'il a été un très bon directeur de laboratoire. Il a toujours défendu ses gens comme Chaudron avant lui. J'aimais beaucoup son épouse avec qui j'avais suivi les cours de chimie minérale et de physique à l'Université de Nancy.

PT : Et Chaudron, comment était son cours ?

HM : Chaudron était un chercheur dans l'esprit, un excellent chercheur. Il avait collaboré avec Georges Claude, le fondateur d'Air liquide, pour la mise au point des oxydes de fer utilisés comme catalyseur dans la synthèse de NH3 [ammoniac]. Il avait beaucoup de rapport avec les ingénieurs de l'IRSID [Institut de recherche en sidérurgie]. Quand je suis arrivée dans son laboratoire, il m'avait demandé d'assister à ses cours. À Nancy, les cours que j'avais reçus me paraissaient faits de certitude, la science sûre telle qu'elle a été faite. Au contraire, le cours de Chaudron portait plutôt sur la science en train de se faire, il était plein de points d'interrogation. Quand il disait un mot, ça lui faisait penser à un autre mot, alors il suspendait sa phrase pour réfléchir et les étudiants ne savaient pas s'il fallait se taire ou parler ; en fait, il fallait se taire car il réfléchissait. C'est ce que pensaient la plupart de ses élèves, je crois : son « cours était plein de silences » comme me l'avait fait remarquer un autre de ses élèves.

PT : Que dire d'autre sur votre expérience dans le laboratoire Bénard ?

HM : En 1977, Bénard a organisé le Colloque ordre-désordre, le 9 juillet 1977, ce qui pourrait vous intéresser. En ce qui concerne les personnes que j'ai rencontrées… Fayard appartenait au groupe Bénard alors que Talbot, avec qui tous deux étaient très amis, avait un laboratoire indépendant dans l'École. Talbot étudiait la corrosion. Je me rappelle qu'on l'avait dépêché comme conseiller technique pour le pont de Tancarville et le tout nouveau centre Pompidou qui montraient des signes de corrosions alarmants. Talbot avait trouvé que les ingénieurs avaient mis de l'étoupe au niveau des vis des constructions, or l'étoupe retient l'humidité. Les rivets s'étaient changés en une multitude de petites piles de corrosion. Il y eut aussi un anglais au laboratoire Bénard : Gordon Rhead qui a disposé pendant longtemps d'une bourse du CNRS. C'était amusant parce qu'il n'avait pas la même sensibilité que nous, qu'il était choqué par certaines choses au laboratoire. Il y avait aussi Albert Masson chez Bénard, il a fait une carrière à Jussieu ensuite. Une autre grand chercheur que j'ai connu est M. Huber. Il avait fait de la cristallographie avec Bragg, il était vraiment très brillant mais ne savait pas en tant qu'enseignant, se mettre au niveau de ses élèves. J'ai travaillé avec lui pour mettre au point une chambre de rayons X au laboratoire, qu'il a d'ailleurs fait construire lui-même. Il avait une réelle passion pour la mécanique. Il était responsable de l'atelier de mécanique à l'ENSCP. Son savoir-faire tenait d'un accident de santé : il avait contracté une tuberculose dans sa jeunesse ; envoyé à la montagne pour guérir, le père de la famille dans laquelle il se trouvait, était mécanicien et lui avait appris le métier. Au cours de nos entretiens, il m'a appris l'usage du réseau réciproque, ce qui simplifiait énormément la compréhension des diagrammes de Laue. Mais il avait fallu le pousser dans ses retranchements pour qu'il m'explique tout car il procédait naturellement par raccourcis. Ensuite, il s'est associé au laboratoire de Collongues quand celui-ci est venu à l'École mais il n'était pas très heureux avec lui. Ils ne s'entendaient pas bien. Félix Trombe travaillait aussi à l'École à l'époque de ma thèse, il menait des recherches au Laboratoire d'électrochimie avant de partir à Odeillo mettre en place le four solaire.

PT : À propos de l'École ?

HM : J'ai toujours entendu dire qu'il manquait de place à l'École. Un jour, j'ai même entendu dire Chaudron à propos d'Yvette Cauchois : « elle me grignote ». Il parlait des sous-sols qui communiquaient : mademoiselle Cauchois avait annexé une salle de l'École !

Fin

Pour citer l'entretien :

« Entretien avec Hélène Mondange », par Pierre Teissier, 4 décembre 2004, Sciences : histoire orale, /spip.php ?article34.

[1] la bible des chimistes français de l'époque : Paul Pascal, dir., Nouveau traité de Chimie minérale, 20 volumes (Paris : Masson, 1956–1964)

Pour citer l'entretien :

« Entretien avec Hélène Mondange », par Pierre Teissier, 4 décembre 2004, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article34.

Lieu : Quartier latin, Paris, France.

Support : non enregistré.

Transcription : Pierre Teissier.

GOODENOUGH John B., 2001-05

2010-02-04T14:39:22Z

John Goodenough, né en 1922 à Iena (Allemagne), est professeur et détient la Virginia H. Cockrell Centennial Chair in Engineering de l'University of Texas, Austin. Jeune homme, il s'est porté volontaire pour servir dans l'armée US comme météorologiste au cours de la Seconde Guerre mondiale. Après la guerre, il a étudié la physique à Northwestern University (près de Chicago) puis a travaillé au Lincoln Laboratory du MIT (Boston, Mass.) et dirigé l'Inorganic Chemistry Laboratory à Oxford University (Angleterre). Ses recherches portent sur les propriétés électroniques et ioniques des oxydes métalliques à la croisée de nombreux champs de recherche. Il a reçu le Von Hippel Award de la Material Research Society (MRS) en 1989 pour sa contribution à l'étude des solides où il s'est illustré par ses aptitudes à constamment lier les concepts de base de la physique et de la chimie à un large éventail de sujets théoriques. Goodenough est aussi reconnu comme l'un des scientifiques les plus influents des solid state ionics, champ de recherche sur les électrolytes solides.

BERNADETTE BENSAUDE-VINCENT (BBV) : So where did you start ? You graduated in chemistry, no ?

JOHN B. GOODENOUGH (JG) : No, not at all. Before World War II, I studied classics and mathematics. I took an introductory course in chemistry my freshman year at Yale as my science requirement for a Liberal Arts degree, but I had no thought of a career in science.

I had been awakened intellectually and spiritually while reading poetry at Groton School and trying to understand the metaphors of the Bible and the Church. Therefore, at Yale I was a young man in search of a calling for my life, so I read considerable philosophy. I became intrigued by the philosophy of science, and as I was reading Whitehead's Science and the Modern World, I came to the conclusion that, if I were ever to come back from the war and if I were to have the opportunity to go back to graduate school, I should study physics.

As an Army Air Force meteorologist, I dispatched tactical aircraft across the Atlantic Ocean during World War II. In 1946, while I was still stationed on the tiny island of Terceira in the Azores awaiting my turn to go home, a telegram arrived telling me to report back to Washington in 48 hours. In Washington, they sent me to Chicago where I was to have a choice to study physics or mathematics at either the University of Chicago or Northwestern University. My old Yale mathematics professor, Egbert Miles, had not forgotten me ! Confronted with this opportunity, I had a flashback to the evening I sat reading Whitehead before the military interruption. It seemed to me that "This is what I am supposed to do !" The next day I went to the University of Chicago to register for graduate studies in physics. When I arrived, the registration officer, Professor Simpson, said to me, " I don't understand you veterans. Don't you know that anyone who has ever done anything interesting in physics had already done it by the time he was your age ; and you want to begin ?"

BBV :It was really encouraging.

JG : Well, it didn't bother me at the time. I was simply grateful that, though still in the Army, my transition back to civilian life was so smooth. I left the Army in 1948 and continued my studies with the G. I. Bill of Rights. When I completed the 32-hour qualifying examination, I decided I did not want to go into nuclear physics, so I signed up to do my dissertation in solid-state physics with Professor Clarence Zener. When I finished my Ph.D. thesis, I had two job offers : one was to be an assistant professor at the University of Pennsylvania and the other was to join the Lincoln Laboratory of the Massachusetts Institute of Technology (MIT). I chose the latter.

ARNE HESSENBRUCH (AH) : What year was that ?

JG : That was 1952. Lincoln Laboratory had been established by the Air Force to develop the Semi-Automatic Ground Environment (SAGE) system for air defense. The system integrated radar, communications. and the digital computer. At that time the digital computer didn't have any memory other than a 16 x 16 bit electrostatic storage tube. Jay Forrester, an electrical engineer, had invented the coincident-current magnetic-core memory. This memory uses a magnetic torroid (core) with a square B-H hysteresis loop for each bit of stored information. Forrester had noted that the magnetic alloys Deltamax and Permalloy had the required square B-H hysteresis loops, and he had used them to prove the concept of his memory. However, the switching speeds were too slow. As an electrical engineer, he assumed the problem was eddy-current damping in his metallic cores, so he had ordered tape cores that were rolled to thicknesses as small as 1/8 mil. But the switching speed was still an order of magnitude too slow. Therefore, he had decided to investigate ferrimagnetic oxides that were insulators. My assignment was to help design a ferrimagnetic oxospinel that had a square B-H hysteresis loop. Those in Europe who had developed the ferrimagnetic spinels did not attempt to do this as they were convinced it was theoretically impossible. The problem was that you cannot role a brittle oxide as you can a metallic alloy in order to align the easy-magnetization axes of all the individual grains of a polycrystalline core, which is how the square B-H hysteresis loops are obtained in Deltamax and Permalloy.

The first thing I did was to analyze what controls the shape of a B-H hysteresis loop. I calculated where the domains of reverse magnetization are nucleated and what hinders their growth in a magnetic field. My calculations showed that if the crystallographic axes of easy magnetization are not well-aligned across a grain boundary, magnetic poles at the boundary may induce nucleation of reverse domains even where the applied magnetizing field is opposed to the magnetization in these domains. However, because the magnetization of a ferrimagnet is much smaller than that of a ferromagnet, nucleation of the reverse domains does not occur in a ferrospinel even where the easy-magnetization axes are misaligned until the magnetization is in the direction of the reverse-domain magnetization. This result meant that it was theoretically possible to obtain a square B-H hysteresis loop in a ferrimagnetic ceramic with unaligned grains provided some other defect could be introduced that would not only nucleate reverse domains at a desired reverse field, but would also release them, once nucleated, to grow until they reversed the magnetization. This was an important finding.

I also analyzed the factors that controlled the switching speed of a magnetic core. It was immediately apparent that the driving field to switch a core was restricted in the memory application to a magnetic field strength H = (H - Hc) < Hc where Hc is the threshold field to switch the magnetization direction. The coercive field Hc in the Permalloy tapes was too small to allow the driving force needed for fast switching. Moreover, the analysis showed that there is an intrinsic damping of spin rotations that would still be present in the absence of eddy currents. It was therefore clear that a somewhat larger coercive field Hc than that of Permalloy was needed, and the remaining problem was to discover the appropriate imperfection that should be introduced to provide many centers for nucleating domains of reverse magnetization at an acceptably large H » Hc.

Meanwhile, my colleagues were empirically mapping the MnO-MgO-Fe2O3 phase field to determine the compositional range of the ferrimagnetic spinels and the influence of annealing temperatures on the shape of the B-H hysteresis loop. It was in this phase field that promising hysteresis loops had been published. We found a certain compositional range rich in manganese in which the spinels were tetragonal rather than cubic. Previous workers had assumed that the tetragonal distortion was due to the disproportionation reaction 2 Mn(III) = Mn(II) + Mn(IV) since this reaction had been observed at the surface of Mn(III) oxides in acidic solution. However, I had read Pauling's The Nature of the Chemical Bond, which helped me to observe that the Mn(III) ion had an orbital degeneracy in a cubic octahedral site that would be removed by a distortion of the site to tetragonal symmetry. I therefore reasoned that at a critical Mn(III) concentration, there would be a cooperative orbital ordering that minimized the elastic energy and that the tetragonal distortion we observed was due to such a cooperative orbital ordering. Unknown to me at the time, Jahn and Teller had pointed out some years earlier that a molecule with an orbital degeneracy would distort so as to lower its energy, but my deduction was the first realization that, in a solid, cooperative orbital ordering to minimize the elastic energy would induce a crystallographic distortion below a transition temperature Tt. This effect is now known as a cooperative Jahn-Teller distortion. At higher temperatures and lower concentrations, the individual site distortions would be disordered and would fluctuate in what is known as a dynamic Jahn-Teller distortion. We also noted that we could obtain square B-H hysteresis loops in compositions that were cubic, but close to those that became tetragonal below a Tt, if the cores were annealed for a specific period at a precise temperature. In this way the technical problem was solved empirically ; the coincident-current magnetic memory proved to be a critical step in the development of the digital computer. However, I didn't know until some time later how the annealing procedure introduced defects that nucleated domains of reverse magnetization.

AH : When did you find this out ?

JG : The Russians were interested in our development of a computer memory. Therefore, I was invited to Sverdlovsk (now Katerinaberg) in 1961 to talk about our work. While there, Shur showed me evidence that the domains of reverse magnetization were nucleated within the grains and not at grain boundaries. In a 1964 experiment concerned with Li+-ion ordering on the octahedral sites of the spinel structure, I observed that the Li+ ions ordered with all trivalent counter cations except Mn(III). I then realized that annealing the memory cores for a specified period at a precise temperature was creating Mn(III)-rich chemical inhomogeneities within the cubic structure in order to reduce, through cooperativity, the elastic energy associated with dynamic Jahn-Teller fluctuations. These chemical inhomogeneities created magnetic poles within grains that were acting as the nucleation centers for reverse-magnetization domains in the memory cores.

BBV : So this is how you came to study oxides ?

JG : Yes. But let me tell you of one other deduction I made at that time that proved critical for my future studies. Néel had understood that the interactions between localized atomic moments may be antiferromagnetic as well as ferromagnetic. An open question at that time was the origin of the magnetic interactions and what determined their sign. Following a suggestion by Kramers, Phil Anderson had formulated the antiferromagnetic superexchange interaction in his Ph.D. thesis with Van Vleck. At the same time, neutron diffraction was developed as an experimental tool with which to measure directly the magnitudes of the atomic moments and their order below a long-range magnetic-ordering temperature. Wollan and Koehler had determined that the magnetic order in the antiferromagnetic perovskite LaMnO3 consisted of ferromagnetic (001) planes coupled antiparallel to one another along the c-axis (Figure 1 below). In La0.5Ca0.5MnO3, the magnetic order within the (001) planes consisted of both ferromagnetic and antiferromagnetic interactions. This anisotropic character of the sign of the (180o - f) Mn-O-Mn interactions in the pseudocubic MnO3 array was a mystery that delayed publication. I realized that the anisotropy must reflect a cooperative orbital ordering at the Mn(III) ions. As I had already worked out in my mind rules for the sign of the superexchange interactions that depended on the occupancies of the interacting orbitals, it was possible to predict the cooperative orbital ordering in LaMnO3 and the charge and orbital ordering in La0.5Ca0.5MnO3 so as to account for the magnetic order. We published back-to-back papers in the Physical Review. Kanamori subsequently provided a more mathematical formulation for the superexchange interactions, and the rules I formulated then are known as the Goodenough-Kanamori rules for the sign of a superexchange interaction. With these rules it has been possible to understand a variety of complex magnetic orderings in magnetic materials. Moreover, these studies led me to an investigation of the change from localized-electron configurations coupled by relatively weak interatomic superexchange interactions to itinerant electrons where the interatomic interactions become stronger than the intraatomic interactions. They also made me realize that, as a physicist, I could play a scientific role building a bridge between the engineer needing a material to realize a device and the chemist charged with the problem of designing a material that would perform the engineering function.

Figure 1. Perovskite structure

AH : And this realization came to you in the mid 1950's ?

JG : Yes, but its evolution was a bit more complex. When we had completed our project with the memory cores and working memories were being realized, Jay Forrester called us to his office. We expected to get a pat on the back, maybe a promotion. Although he spent 30 seconds congratulating us on a job well done, he had another purpose. "Now that you have worked yourselves out of a job, what are you planning to do ?" he asked.

AH : What an interesting managerial technique.

JG : Half the group decided to take the technology to industry ; I decided to stay and spent the next weekend figuring out what I should do next. I came up with the idea of a magnetic-film memory that would switch by a simultaneous rather than a sequential rotation of spins.

AH : Do you remember when that was ? Do you remember the year ?

JG : I believe it was 1956 or 1957.

BBV : So you stayed at the MIT Lincoln Laboratory for that ?

JG : Yes. I was put in charge of this new project as well as of the old ceramics laboratory. Since several people had left, I was permitted to hire a few new people. One of those I hired turned to me about a year later and said, "I want to become famous ; let me take charge of the magnetic-film project." He was an experimentalist, so I said, "All right, you can have it !" I gave my full attention to what was left of our ceramics laboratory. It turned out that the magnetic-film memory only filled a small niche in the market. It proved a difficult technology, and other developments came along that were more competitive. It appeared to be a good idea at the time, but it didn't become a winner. However, my decision to give the magnetic-film project to others made me concentrate on solid-state chemistry and gave me about 12 years in which I did some fundamental studies and wrote two books.

BBV : Which one : Metallic Oxides ?

JG : I wrote first Magnetism and the Chemical Bond. I realized I could tell a great deal about the nature of the chemical bond from the magnetic order and the crystallographic distortions because I knew how the signs of the interatomic exchange interactions depend on the number of electrons in the interacting orbitals and how cooperative orbital ordering would optimize the exchange interactions. In those days many people were interested in investigating the complex magnetic orderings revealed by neutron diffraction and in interpreting the origins of these complex orderings. For example, I was able in 1961 to show that where the Jahn-Teller distortions are fluctuating, the (180o-f) Mn(III)-O-Mn(III) interactions in a perovskite became isotropic, ferromagnetic vibronic superexchange interactions. Vibronic superexchange interactions are now returning as a subject of interest ; and we have recently shown they play an important role in the manganese oxides that exhibit a colossal magnetoresistance. Moreover, Tom Kaplan of my group was calculating the ground-state magnetic order where there were competitive interactions that gave rise to spiral-spin configurations, configurations that were quite complex in spinels where a spiral-spin configuration was superimposed on a Yaffet-Kittel triangular-spin configuration. I extrapolated the rules for the superexchange interactions to the case of itinerant-electron magnetism, reasoning that it was the perturbation expansion of the mathematical description and not the physics that broke down at the crossover from localized-electron to itinerant-electron magnetic interactions. In that book, my primary interest was in the variety of magnetic orderings that were observed in the d-block transition-metal alloys and compounds.

My book Les oxydes des métaux de transition is a French translation of a long review article entitled "Metallic Oxides". This review was an extension of my former book ; it concentrates on the transition from localized to itinerant electronic behavior. Localized-electron behavior occurs where the intraatomic interactions are stronger than the interatomic metal-metal or metal-anion-metal interactions, which is why the interatomic interactions between localized-electron configurations can be treated in second-order perturbation theory. The conventional one-electron band theory of itinerant electrons applies where the interatomic interactions are much stronger than the intraatomic electron-electron interactions. While I was still a graduate student, Mott had called attention to the fact that NiO should be a metal rather than an antiferromagnetic insulator according to the band theory. It is necessary to introduce into this theory the on-site electron-electron interactions to account for the localized-electron configuration of NiO. Hubbard presented the Hamiltonian that introduced this term, and the transition from antiferromagnetic insulator to Pauli paramagnetic metal where a band is half-filled is called the Mott-Hubbard transition. I realized that in oxides the metal-oxygen interactions open a large energy gap between the bonding and antibonding states of the valence s and p electrons ; d-electron redox energies may be found within this energy gap. Moreover, isostructural oxides were known of which some members were metallic and others were antiferromagnetic insulators. For example, TiO is a metal whereas MnO is an antiferromagnetic insulator ; SrVO3 is a metal whereas LaVO3 is an antiferromagnetic insulator. These observations meant that I should be able not only to determine the number of electrons in a d-electron bond from the sign of the spin-spin interaction across it but also to study the transition from localized to itinerant electronic behavior in d-block transition-metal oxides without the interference from overlapping broad bands that occurs in the magnetic alloys. However, our experiments designed to monitor this transition were frustrated at that time by lattice instabilities that gave rise to either phase separation or the appearance of a charge-density/spin-density wave (CSW/SDW). Before we could unravel why this was so, Senator Mansfield passed an amendment that forbade federally supported facilities like Lincoln Laboratory from engaging in fundamental research not targeted on a specific engineering application. So, I was told I could no longer continue my fundamental studies.

AH & BBV : When was this ?

JG : It was about 1970. So I had had about 12 years from 1958 to 1970 to do fundamental research.

AH : Was all of this done at Lincoln Laboratory ? Were you involved in the organization of the Department of Materials Science and Engineering at MIT ?

JG : Yes, the work was done at Lincoln Laboratory. No, I was not involved with the MIT-campus bid to establish an NSF-sponsored Materials Science Institute.

To return to my story, when I was told I couldn't continue untargeted fundamental research, I was forced to think through what I and my group should do next. It was the early 1970's, and the first energy crisis had arrived. People were lined up at the gas stations. So it seemed obvious that I should consider doing something related to energy.

AH : But there is a gap of more than a year because the energy crisis was in 1973.

JG : Yes, there was a gap during which time I developed a sole for a travelling-wave amplifier ; we made a MgO-Au composite that improved the secondary-electron emission by over a factor of 100. But the project manager who requested this development became preoccupied with a big radar sink for money, so the development was never exploited.

In the same period, researchers at the Ford Motor Co. had discovered fast Na+-ion conduction in a ceramic, sodium-beta-alumina. They proposed using it as the electrolyte and separator of a Na-S battery that used molten sodium as the anode and a molten sulfur compound as the cathode. It would operate at 300o C. I was asked by the DOE to be on the evaluation panel of this project. It was my introduction to solid alkali-ion electrolytes and to batteries. I was subsequently invited to Stanford University for two days to give a seminar on my work on the electronic properties of oxides with the perovskite structure and to interact with various solid-state research groups there. Each professor had his own fiefdom, and one of those was under Bob Huggins who asked me, "How would you design a Na+-ion electrolyte ?" Since perovskite-related materials were on my mind, I replied, "I would choose a host framework that contained tunnels as occurs in the hexagonal sodium-tungsten bronze, but I would choose structures in which the tunnels run in more than one direction and intersect one another. I would also choose a main-group element rather than a transition-metal atom as the framework cation to obtain a solid electrolyte, i.e. a framework that is not an electronic conductor." As I was flying back to Boston, it occurred to me that sodium-beta-alumina was a framework structure in which the mobile Na+ ions move in planes containing intersecting tunnels. I was interested to learn that, subsequent to my visit, Huggins and his post-doc Stan Whittingham used hexagonal tungsten bronze as a sodium-insertion electrolyte for measuring Na+-ion electrolytes. Meanwhile, I had decided to investigate Na+-ion conductivity in framework structures having tunnels running in three dimensions as I reasoned that a ceramic with three-dimensional Na+-ion conductivity would be superior to one with only two-dimensional Na+-ion conductivity. I embarked on this study before I turned to the problem of clean energy.

An analysis of the energy problem showed that there were only four alternatives to fossil fuels as energy sources : hydropower, geothermal, solar (including wind), and nuclear energy. Hydropower was already being exploited and geothermal energy is geographically limited. I didn't want to consider nuclear energy, so I analyzed the solar-energy problem.

AH : Why didn't you want to do nuclear ?

JG : I wasn't a nuclear scientist and we weren't a nuclear laboratory, so it wasn't appropriate for us. Similarly, wind energy was not matched to my interests. It would have been appropriate for us to work on photovoltaic cells, but others with more experience of broad-band semiconductors were doing photovoltaic development, so I began with wavelength-selective films for passive thermal heating. We developed some of these, but I soon realized that long-term energy storage was a key to harnessing solar energy. Since energy is most versatily stored long-term as chemical energy, I had the idea to generate hydrogen from water by photoelectrolysis. I soon discovered that Fujishima and Honda had already discovered this effect on TiO2 I also proposed the use of yttria stabilized zirconia for the electrolyte of a solid oxide fuel cell to be operated with the waste heat of a conventional power plant. As a third leg, I proposed continuing work on Na+-ion solid electrolytes for the Na-S battery. In that effort, I identified several framework structures (I called them skeleton structures) that supported three-dimensional, fast Na+-ion conductivity. One of these was Na1+3xZr2(P1-xSixO4)3, which has the hexagonal Fe2(SO4)3 framework. My colleagues named it NASICON, standing for NA SuperIonic CONductor, just as I was leaving Lincoln Laboratory.

AH & BBV : Who chose that name ? What was the name of your colleague who coined the word NASICON ?

JG : There were two I think : Alan Strauss and Kirby Dwight. When I requested funding to work on these energy products, the bureaucrats in Washington said, "The National Atomic Energy Laboratories are in trouble because atomic energy has gone out of favor. Therefore, the DOE will only support energy programs in these laboratories. Lincoln Laboratory is an Air Force laboratory and should involve itself with problems directly related to the Air Force." Therefore I decided that I should leave the MIT Lincoln Laboratory.

I had always wanted to help the third-world countries, and solar energy was a program that would be well suited to some of the countries newly enriched by the increase in oil prices. Therefore, when I was approached by an Iranian about the possibility of heading up a research institute in that country, I decided to explore the idea. I went to Tehran and raised $7 M from the Shah for an institute to be associated with the Aryamehr University there.

AH : When was this ?

JG : 1974 and 1975. While contemplating back in Boston whether to make such a move, a letter from Oxford University, England, arrived asking me to put my name in nomination for Professor and Head of the Inorganic Chemistry Laboratory. My wife did not hesitate to recommend that I put my name in nomination, and I thought, "If the people at Oxford have that much imagination, then perhaps that is what I should do." I was duly elected, and in 1976 I took up the post in Oxford.

BBV : So you abandoned your Iranian project ?

JG : I did.

BBV : And the $7 M ?

JG : Yes. As it turned out, within two years the Shah was ousted, the American Embassy was taken hostage, and the Institute I had helped establish was abandoned. My election as Professor and Head of the Inorganic Chemistry Laboratory at Oxford was quite extraordinary as I had had only one course in Qualitative Chemistry as a Yale freshman in 1940 and one in Organic Chemistry in 1948 at the University of Chicago. I came into Chemistry by the back door working with solid-state chemists trying to build a bridge between them and the engineer and using their expertise to design experiments to explore fundamental physics questions in solid-state science.

AH : Is that what the Oxford Inorganic Chemistry Laboratory was interested in ?

JG : The Oxford Inorganic Chemistry Laboratory included preparative organometallic chemistry, chemical crystallography, bioinorganic chemistry, thermodynamics, electrochemistry, and several spectroscopic groups as well as solid-state chemistry. My predecessor, Professor Stuart Anderson, was a solid-state chemist, and there was a preference to maintain continuity in that field. As I had been working with solid-state chemists, I presume the Dons thought I would bring a solid-state program that complemented other on-going activities there.

Initially, I decided to investigate the chemistry of the photoelectrolysis of water on oxide surfaces and to extend my studies of ionic transport in solids to include proton conduction in oxide-particle hydrates and insertion compounds for cathodes of rechargeable lithium batteries. These topics introduced me to electrochemistry as well as to catalysis, and I later undertook studies of methanol oxidation at the anode of a direct methanol-air fuel cell, of the oxygen-reduction reaction at fuel-cell cathodes, and the mechanistics of a partial-oxidation reaction on phosphopolymolybdates. The study having a large commercial impact was the development of a cathode for the lithium-ion rechargeable batteries that have enabled realization of the cellular telephone and laptop computers, for example.

In the early 1970's, Ted Geballe and his student Fred Gamble were investigating at Stanford the insertion of various chemical species between the layers of the metallic sulfide TiS2 in order to demonstrate the existence of two-dimensional superconductivity. Michel Armand, then a student with Bob Huggins, was interested in the possibility of reversible alkali-ion insertion in TiS2 for use as a battery electrode ; Stan Whittingham of Huggins' group had used hexagonal tungsten bronze, a one-dimensional Na+-ion conductor, as an electrode, and TiS2 offered two-dimensional conductivity. Brian Steele of Imperial College, London, suggested at a meeting (proceedings edited by Van Gool) the use of TiS2 as the cathode of a lithium battery. At that time, about 1973, the energy crisis had stimulated the EXXON corporation to expand into an energy company ; Stan Whittingham and Fred Gamble were hired to initiate an energy program. Before I left for Oxford in 1976, Stan Whittingham published a paper in Nature showing that lithium can be inserted rapidly and reversibly into TiS2 over the entire solid-solution range LixTiS2, 0 < x < 1, and that the compound gives a fairly flat open-circuit voltage versus a Lithium anode of about 2 V. This publication generated extensive interest, and EXXON committed considerable resources to the commercialization of a Li/LiClO4/TiS2 battery. However, a passivation layer at the anode resulted in lithium dendrite formation on recharge. After a few cycles, the dendrites grew across the explosive LiClO4 liquid electrolyte, shorting out the cell and blowing up the laboratory. Safety concerns eventually led EXXON to abandon the project and, subsequently, its expansion as an energy company.

As a consultant for the DOE on the Na/S battery, I had become increasingly aware of these developments. It became clear to me that to avoid these safety problems, it would be necessary to develop an anode that was an insertion compound. However, such an anode would lower the voltage of the cell. I considered the origin of the metallic conductivity of TiS2 and understood that it would be necessary to insert lithium into a metallic oxide if a larger cell voltage was to be obtained. However, unlike the sulfides, there are few layered oxides. On the other hand, there are several LiMO2 compounds having a transition-metal atom M that have layered structures analogous to that of LiTiS2, so I decided to investigate how many Li atoms can be removed before the oxide structure becomes unstable. Extraction of lithium meant operating on the M(IV)/M(III) redox couple. To obtain a large cell voltage, I wanted a cation for which the energy of the M(IV)/Mn(III) redox couple was unusually low ; and to prevent migration of M cations into the depleted lithium layer, I wanted both the M(IV) and M(III) species to have a strong octahedral-site preference since migration was through a tetrahedral site. Therefore, I chose chromium, cobalt, and nickel as possible M atoms. At that time, Koichi Mizushima was visiting me from the University of Tokyo, so I asked him to perform the experiments. We were delighted to find that we could take out most of the lithium from the cobalt and nickel oxides without migration of these cations to the depleted lithium layers. However, stable reversible lithium extraction is restricted to 50% - 60% extraction. Nevertheless, this amount gave a reasonable cell capacity at a voltage versus a Lithium anode of about 4 V.

At that time, all we had was a cathode material. The British battery makers were not interested ; they could not imagine beginning with a discharged cathode. A Japanese worker at Sony had been quietly investigating a special waste carbon as an anode host for the insertion of lithium in order to circumvent the safety problem of the battery, and he recognized immediately that my cathode was what was needed to make a high-energy-density rechargeable lithium battery. The Sony Corporation was looking for such a battery to enable marketing of the cellular telephone and the laptop computer. They have done an excellent job of commanding the market. It is my understanding that at the present time approximately 20% of the cobalt production in the world is used in these batteries. Already expensive, the price of cobalt threatens to go even higher. Therefore there continues to be a strong incentive to find less expensive alternatives.

With the publication of our results, Michael Thackeray was sent from South Africa to work with me. When he arrived, he said that he wanted to find a cheaper cathode and that he was inserting lithium into magnetite, Fe3O4. I was surprised because spinels were considered to be gem-like materials having little solubility of interstitial cations. However, I had heard Bruno Scrosati of Rome claim the same thing two weeks earlier, so I told Thackeray to repeat the experiment in my laboratory. This he did, and then I realized that the insertion of lithium was converting the spinel to a rock-salt structure. Both structures have a face-centered-cubic oxide-ion array. In the rock-salt structure, cations occupy all the octahedral sites of this array ; in spinels, only half of the octahedral sites are occupied to form a three-dimensional framework with an interconnected interstitial space of face-shared octahedral and tetrahedral sites. In the LiMO2 oxides, the M atoms occupy alternate (111) planes of octahedral sites. In the spinel, the remaining one cation to four oxide ions are ordered in tetrahedral sites of the interstitial space ; with two Li atoms for four oxygen atoms, the layered LiMO2 phase is more stable. Insertion of lithium into Fe3O4 was leaving the spinel framework intact ; the lithium entered octahedral sites of the interstitial space and pushed the tetrahedral-site iron into octahedral sites in a cascade. When I realized what was happening, I told Thackeray to insert lithium into the spinel Li[Mn2]O4 since I knew that in this spinel only Li+ ions would occupy the interstitial space and the [Mn2]O4 framework, though becoming metastable, would remain intact. This he did, and we found a flat open-circuit voltage versus a Lithium anode of 3 V. Removal of lithium gave 4 V. The possibility of an inexpensive cathode transporting Li+ ions in three dimensions stimulated extensive research on this cathode material even though the Li+ ions do not move as rapidly in this three-dimensional framework as they do in the layered oxides.

Unfortunately the manganese spinels do not retain their capacity on repeated cycling in the 4 V range. In the 3 V range, the flat open-circuit voltage reflects a two-phase range ; as the Mn(III) concentration increases with lithium insertion, a cooperative Jahn-Teller deformation from cubic to tetragonal symmetry occurs, and the deformation on repeated cycling tends to crack larger particles so as to cause capacity fade in the 3 V range as well. Recently, Sun Ho Kang came from South Korea to my laboratory in Texas, and we found that this latter problem can be solved by a simple ball-milling procedure that breaks the particles into many small microdomains. However, it looks like the manganese spinels will be restricted to the 3 V range and will face serious competition from other developments.

In order to increase the free interstitial volume for three-dimensional motion of the Li+ ions, I decided to reinvestigate the NASICON structure, but this time as an insertion electrode rather than as an electrolyte. The hexagonal M2(XO4)3 framework is found with several transition-metal atoms M and polyanions having X = Si, P, S, Mo(VI), or W(VI). For example, hexagonal Fe2(SO4)3 has the structure of the NASICON framework. Although the iron atoms are separated by (SO4)2- polyanions, the electronic transport is better than the Li+-ion transport. I was immediately struck by the observation that in this structure, the Fe(III)/Fe(II) redox couple gives 3.6 V versus lithium whereas the Fe2(MoO4)3 and Fe2(WO4)3 frameworks give 3.0 V. Changing the counter cation in the polyanion shifts the working redox energy just as shifting the Li+ ions from tetrahedral to octahedral sites in the [Mn2]O4 spinel framework changes the energy of the Mn(IV)/Mn(III) couple by 1 eV. Moreover, the more acidic polyanions bring the Fe(III)/Fe(II) redox couple into a useful energy range, thereby making an iron oxide a competitive electrode material. This fact was noted by Shigeto Okada of Nippon Telephone and Telegraph, and he was sent to my laboratory to work on stabilization of the hexagonal form of LixFe2(SO4)3. While he was with me, I asked my post doc, Kirakodu Nanjundaswamy, to investigate electrochemically the relative energies of several transition-metal redox couples in the NASICON structure with (SO4)2- and (PO4)3- polyanions. All the redox energies were found to shift by 0.8 eV on changing from (SO4)2- to (PO4)3-. At that time, my student Akshaya Padhi was looking for a thesis topic, so we decided to broaden the study by investigating lithium insertion into several different framework structures containing polyanions. In the course of that study, we found that all the lithium could be extracted from the olivine LiFePO4 and that it gave a constant open-circuit voltage versus Lithium of 3.4 V over most of the compositional range 0 < x < 1 of Li1-xFePO4 due to a small distortion of the FePO4 framework with x = 1. Professor Michel Armand of the University of Montreal recognized immediately that this material would be an excellent match to the polymer Li+-ion electrolyte that he had developed, so he persuaded the Hydro-Quebec Corp. to license our patent. He and Michel Gauthier of Hydro-Quebec then developed a fabrication procedure for achieving the full capacity on repeated charge-discharge cycles at a practical rate. This electrode material promises to be an inexpensive and environmentally friendly replacement for the present Li1-xCo1-yNiyO2 cathode, but other more competitive materials may yet be developed.

BBV : When did you come up with this new oxide ?

JG : In 1994.

BBV : So it is fairly recent. Were you still in Oxford ?

JG : No, I left Oxford in 1986. At that time, a generous donor had given to the University of Texas $8 M for Chairs in Science and Engineering provided the university could match it. In the end, $32 M was raised for a set of chairs, one of which was offered to me. From the endowment, they pay half my salary with enough left over to pay for a secretary and some expendables. Moreover, I didn't have to retire at 67, so I haven't yet ; I am an old tiger enjoying working here.

BBV :So you have a laboratory facility here ?

JG : Yes, we have managed to build up a nice laboratory in Texas. My battery work has been funded by the Robert A. Welch Foundation of Houston, TX. I am most grateful to that organization. They also supported the student with whom I developed the perovskites as solid oxide-ion electrolytes. Keqin Huang came from China to work with me on a solid oxide fuel cell (SOFC) based on the perovskite electrolyte Sr- and Mg-doped LaGaO3, first discovered by Ishihara of Japan. While still at Lincoln Laboratory, I had worked with a mechanical engineer to propose the SOFC as a bottoming cycle for a power plant ; our analysis was based as yttria-stabilized zirconia (YSZ) as the oxide-ion electrolyte. The DOE has since then provided Westinghouse with massive funding to develop the SOFC. Huang and I systematically developed a package of electrodes, buffer layers, and interconnects for a SOFC based on the gallate electrolyte, which we showed gave a competitive performance to SOFCs based on yttria-stabilized zirconia. Westinghouse has now hired Keqin Huang. It is not clear that the gallate electrolyte will be the winner, but the chemical lessons we learned in the process of building our cell will help in the selection of electrode materials and the use of buffer layers. I believe the SOFC technology, though difficult, will find commercial realization in the relatively near future.

But in 1986, while I was moving to Texas, Bednorz and Müller reported the discovery of high-temperature superconductivity in the copper oxides. This discovery brought me back to my study of the unusual physical properties that are encountered at the crossover form localized to itinerant electronic behavior in transition-metal oxides with perovskite-related structures, a study I had been forced to abandon in the early 1970's. Shortly after my arrival in Texas, a letter arrived from a physics professor at the Jilin University in northern China. He had a student interested in the high-pressure work we had done while I was at Lincoln Laboratory, and he wished to have him come to do a Ph.D. dissertation with me ; the degree was to be granted by the Jilin University. I arranged for the student, Jianshi Zhou, to come to the U. S. as a visiting scientist, and I put him to work on the copper-oxide superconductors. Fortunately for me, he continues at Texas in a most fruitful collaboration. We have used high pressure as a variable that allows not only the preparation of materials not accessible at ambient pressures, but also to monitor the change in electronic properties with increasing interatomic interactions in the region of crossover from localized to itinerant electronic behavior. High-temperature superconductivity in the copper oxides and a colossal magnetoresistance in the manganese oxides are found, for example, in mixed-valent systems at this crossover. I have invoked the Virial Theorem of mechanics to show that we can expect a first-order transition at the crossover with a (M-O) equilibrium bond length that is larger for localized than for itinerant electronic behavior. With this idea, we have demonstrated experimentally that where phase separation would occur at too low a temperature for atomic diffusion, it may be accomplished in perovskite-related structures by cooperative atomic displacements. Where these displacements are ordered and static, they give rise to the stabilization of charge-density/spin-density waves (CDW/SDWs). In a mixed-valent system, the cooperative oxide-ion displacements may remain only short-range ordered, in which case the electrons are strongly coupled to bond-length fluctuations that may either segregate a mobile, hole-rich phase or introduce vibronic particles consisting of hybridized electrons and oxygen vibrational modes. We have published a long review on this subject in volume 98 of Structure and Bonding that I edited. Our emphasis on bond-length fluctuations as the fundamental feature of the high-temperature copper-oxide superconductors has not yet been well-received by the physics community, which has concentrated on the importance of the interatomic spin-spin exchange interactions. Given correlation fluctuations that separate spin-rich and hole-rich regions, the spin-spin interactions clearly play a role, but they are associated with bond-length fluctuations that are a general phenomenon associated with the crossover from localized to itinerant electronic behavior. Unusual physical properties are found wherever the fluctuations are not ordered into a static CDW/SDW or do not give rise to a conventional phase separation as a result of atomic diffusion. However, short-range bond-length fluctuations are not detected directly by conventional diffraction techniques. Professor Takeshi Egami of the University of Pennsylvania has developed pair-distribution-function analysis of pulsed-neutron data that is providing a picture of the structure at time scales less than 10-13 seconds ; the data give direct confirmation of the existence of bond-length fluctuations.

AH : They model it on the computer ?

JG : The data analysis is done with the computer, but the pulsed-neutron data that are analyzed provide a picture of the lattice taken within a time that is short relative to a fluctuation. Egami is a careful experimentalist who was willing to develop a technique that could test our hypothesis directly ; his data are quite convincing, and I am very happy that he has been able to provide details of how these fluctuations order themselves into stripes, a detail that our indirect probes could not provide.

AH : So it's the matching of the neutron data with the simulation of the theory that is convincing because the two of them are similar.

JG : Not quite. There is no theoretical simulation of a model. Rather, there is an analysis of the data that provides a direct picture of the positions of the atoms in a short time interval rather than an average position obtained over a long time period. I believe their data on the copper oxides show that the bond-length fluctuations develop more and more long-range order on cooling to the critical temperature for the onset of superconductivity. I believe they order into a travelling CDW/SDW in which the electronic wavefunctions are hybridized with phonons to become heavy electrons, superconductive pairs condensing from the heavy electrons.

AH : So you don't go to many conferences either ?

JG : I go to a variety of conferences in electrochemistry, ceramics, materials science, solid-state chemistry, and physics. I limit myself to those where I am asked to give an invited or plenary lecture. This usually involves several invited talks a year, at least half of which are in Europe.

BBV : Over your career, you seem to have migrated from one discipline to another, finally coming back to where you started.

JG : I wouldn't say it was from one discipline to another, but from one inquiry to another and back again. But perhaps that's the way research goes, in spirals. I have found myself asking one question of a material at one stage and then returning to it to ask another question at a later stage. For example, when I applied the idea of cooperative orbital ordering to LaMnO3 and La0.5Ca0.5MnO3 to explain not only the structure but more fundamentally the anisotropic magnetic order with the formulation of the rules for the sign of the spin-spin superexchange interactions, Wollan and Koehler had also reported no magnetic order in the perovskite LaNiO3. I realized that the Ni(III) ion must have a low-spin configuration, but the lack of a cooperative orbital ordering as well as of magnetic order remained a mystery as everyone assumed the oxides are ionic compounds. At that time we were interested in how the mismatch of the equilibrium bond lengths of the two cations of a perovskite determined distortions of the structure from cubic symmetry or the stabilization of hexagonal polytypes. I went on to consider how the electronic properties would change as the strength of the interatomic spin-spin interactions increased. The metal-metal interactions across shared octahedral-site faces or edges seemed to be an obvious place to look for this change, and indeed TiO and VO are metallic whereas MnO is an antiferromagnetic insulator in which the Mn-O-Mn spin-spin interactions are stronger than the Mn-Mn interactions. When Morin discovered a semiconductor-metal transition in VO2 that is due to the onset of a CDW, I was prepared to think about it. Below the transition temperature Tt ? 67oC, the octahedral-site V(IV) sharing edges along the c-axis pair by forming V-V homopolar bonds. I realized that a change in the translational symmetry can transform a partially filled, narrow band of itinerant electrons into electrons of isolated molecular clusters. Professor Peierls had suggested such a possibility as a one-dimensional exercise in a physics textbook that I have not read, so the change from a one-dimensional narrow band to homopolar bonding between pairs of atoms of the chain is now known as a Peierls distortion. I further noted that MoO2, which is isostructural with VO2 at high temperatures, showed a similar Mo-Mo pairing at lower temperatures, but MoO2 remains metallic. The Mo(IV) ion has an additional d electron that occupies an orbital involved in Mo-O-Mo p bonding, so it dawned on me that covalent hybridization of metal-d and oxygen-p electrons could make the metal-oxygen-metal interactions strong enough to delocalize the electrons. This realization solved for me the mystery of LaNiO3. Paul Raccah had just joined my group from France and needed a project. I told him to prepare LaNiO3 ; he should find it is metallic ! Indeed, it is metallic. This was the first demonstration that the metal-oxygen orbital hybridization in an oxide could be strong enough to de-localize a d-electron configuration as a result of 180o M-O-M interactions. It solved the origin of the metallic conductivity of the sodium-tungsten bronzes, which had been puzzling since its discovery in about 1951. It also led me to map out where the electrons are localized and where they are itinerant in the single-valent oxides with perovskite structure as well as in oxides where metal-metal interactions de-localize the d electrons. At that time, I was unable to prepare the perovskite family LnNiO3, where Ln is a rare-earth atom, as these syntheses require a high oxygen pressure. Later, in Texas, J.-S. Zhou and I were able to show that LaNiO3 contains strong-correlation fluctuations within the band of itinerant electrons. As the size of the Ln3+ ion decreases, narrowing the s* band even further, these strong-correlation fluctuations order into a CDW/SDW below a transition temperature Tt that increases progressively with decreasing size of the Ln3+ ion. We were also able to show that the strong-correlation fluctuations introduce a progressive increase of a Curie-Weiss component in the paramagnetic susceptibility ; the character of the transition from Pauli to Curie-Weiss paramagnetism in the perovskites was addressed experimentally for the first time.

As another example, I had studied with Don Wickham the magnetism of the rock-salt system Ni1-xLixO, 0 £ x £ 0.5, and observed how the Li+ ions order into alternate (111) octahedral-site planes as x approaches x = 0.5. I was later to go back to this layered structure to demonstrate lithium extraction for the cathode of a lithium-ion battery.

I could cite other examples. Already in my first years at Lincoln Laboratory I understood the need to build bridges between physics, chemistry, and engineering in order to be able to design materials that would perform a desired engineering function as well as to explore the fundamental questions of solid-state science. This interdisciplinarity is the hallmark of materials science.

BBV : Do you think of yourself as a physicist, or a solid-state chemist or...

JG : I am a solid-state scientist.

AH : Don't you identify with any of the established categories ?

JG : Well, I would like the chemists to think I am a chemist, but I'm afraid they think I am a physicist. On the other hand, the physicists think I am a chemist.

BBV : That's like the story about Einstein who is a Jew in Germany, but he was a German in Switzerland.

JG : Well, that's life.

BBV : Yes, it's life. But you have been publishing in several journals.

JG : Yes, of course. I am a Fellow of the American Physical Society, and I publish a great deal in the Physical Review and Physical Review Letters. I also was elected as a Chemist to be a Foreign Associate of L'Institut de l'Academie des Sciences de France as I have published extensively in the Journal of Solid-State Chemistry, in the Journal of Electrochemical Society, and in other chemistry journals. I was elected a Fellow of the National Academy of Engineering because I publish in materials science journals such as the Materials Research Bulletin. Thus I identify with all three established categories and am an Associate Editor of several journals.

BBV : I understand you have strong links with the solid-state chemistry community.

JG : Yes, I do. I believe the solid-state chemistry community has been the most appreciative of my attempts to build a bridge between the chemist and the physicist. I have used the experimental strategies of the chemist to explore problems of interest to the solid-state physicist.

BBV : So finally the physicists are accepting you ?

JG : Yes, but sometimes I think a bit reluctantly by some.

AH : And you also publish in Nature.

JG : Yes, I publish in Nature.

BBV : Have you had any links with the people in Grenoble ?

JG : Yes, but no collaborative links aside from a few with workers using their neutron-diffraction facilities. My ties to Grenoble go back to 1954 when I paid a visit to L. Néel, R. Pauthenet, and E. F. Bertaut long before they built up the great facilities there. In 1954, I was able to take a one month leave of absence in addition to my annual vacation, and my wife and I made a splendid tour of Europe. Since I had been working on spinels, I decided to take a side trip from Switzerland to Grenoble to pay my respects to Louis Néel who received a Nobel Prize for his work on ferrimagnetism in these oxides. I also wished to see Erwin Bertaut who had done much pioneering x-ray diffraction on the spinels, perovskites, and garnets ; Pauthenet made the magnetic measurements. I brought to Bertaut my deduction of cooperative orbital ordering in the manganese and copper spinels, and he was delighted to have an explanation of his observations. From that time I have felt a special friendship for Bertaut and for Pauthenet before his too early death. Louis Néel was kind enough to invite me to give a paper at the next International Conference on Magnetism that was held in Grenoble. When I was in England, I went each Spring to Grenoble to referee applications for neutron-diffraction studies there. I have also been invited for 10-day stints to lecture at the University of Grenoble and at the CNRS Crystallography Laboratory that was founded by Bertaut.

BBV : And what are your relations with Professor Paul Hagenmuller ? He is in exactly the same field as you.

JG : My relations with Paul Hagenmuller also go back a long way. The CNRS decided to diversify from Paris some important scientific centers. Grenoble was the first ; Néel, Bertaut, and Pauthenet built up that facility. In the early 1960s Hagenmuller was chosen to develop a solid-state chemistry group in the University of Bordeaux. Already in the early 1960's, before his building was completed, Hagenmuller came to visit me in Lincoln Laboratory. I strongly advised him to build contacts with the physics community. He has had a little difficulty bringing a physics component into his laboratory, but he did develop techniques for physical measurements and his people have interacted with physicists in Paris and Grenoble. In the late 1960s I was able to accept an invitation from him to spend three months in his laboratory ; it was on that occasion that André Cassalot translated my "Metallic Oxides" into the French book Les oxydes des métaux de transition. I have visited, lectured, and collaborated with his people over the years ; and in 1976, Hagenmuller offered me a post in Bordeaux that I declined in favor of the position at Oxford. I received a Docteur honoris causa from the University of Bordeaux in 1967, and I have served as a CNRS advisor to his laboratory as well as to the Bellevue laboratory of Guillaud in Paris. I have had numerous enjoyable contacts with colleagues in France, including an early invitation from Jacques Friedel to spend a year with him in Paris and acting as examiner for many a Thése d'État at several universities. I have had less interaction with Germany.

AH : Why is that ?

JG : I believe it is just a coincidence. Right after World War II, Germany emphasized the rebuilding of their industrial base. Although there was a strong solid-state chemistry tradition in Germany, the chemists like Rabenau and Hoppe were isolated in different universities and were primarily preparative and structural chemists. The Max Planck Institutes did not establish solid-state centers until relatively recently, and they have been slow to recognize the need for interdisciplinarity. However, I have had a little contact with Arndt Simon and Manuel Cardona of the Max Planck Institute in Stuttgart, but there is relatively little overlap between their work and mine. I served with Manuel Cardona as an advisor to the Spanish CSIRO for several years. I also served as an advisor to the Materials Science Center in the University of Groningen when it was first being established under George Sawatzky on the retirement of Franz Jellinek and Cornelius Haas there. I have been better received in Europe than in the U. S.

BBV : But the solid-state community is small here.

JG : Yes, the solid-state chemistry community is only now becoming prominent in America. When I came to Lincoln Laboratory in 1952, the chemistry departments in this country considered that solid-state chemistry was only an exercise in stamp collecting as the community consisted largely of structural chemists. It was only in a few industrial interdisciplinary laboratories like the Bell Telephone Laboratories and IBM that the solid-state chemists were interacting with engineers and physicists. However, even there they served the physicists and engineers by providing them with single crystals. When I took charge of the small ceramics facility at Lincoln Laboratory, I said to myself that I wanted to make the physicist serve the chemist rather than the other way around, so I said to my people, "We have got to be the dog, not the tail ; we will let the physicists be the tail, not the other way around." I suppose it was that attitude that made Oxford accept me as a chemist.

AH : It seems that you have had quite a lot of contact with the Chinese and Japanese.

JG : I see you have done a lot of homework.

AH : We can see Chinese and Japanese names on your publications in the last five years.

JG : You should also see several Indian names. In my years in Texas I have had post doctoral and doctoral students from China and India as well as visiting scientists from Korea and Japan. I have already told you about J.-S. Zhou and Keqin Huang. My contacts with Japan also go back a long way. My first trip to Japan was in 1961. I had been invited there the year before by Nagamiya, but I could not go then. Junjiro Kanamori was his student, and he went to work with Jacques Friedel when I couldn't get leave to spend a year in Paris. Nagamiya and Kanamori were interested in my rules for the sign of the superexchange interactions and my prediction of cooperative orbital ordering in LaMnO3. There were other Japanese working on ferrites who came to visit me before 1961. One was Shuichi Iida of the University of Tokyo. It was his assistant, Koichi Mizushima, who came to me in Oxford and did the initial experiments on the Li1-xCoO2 and Li1-xNiO2 battery cathodes.

During my visit to Japan in 1961, Pauthenet of Grenoble and I were invited by Eiji Hirahara to lecture in Sendai ; I exchanged Christmas greetings with Hirahara every year until his death and interacted with him on the MnP-MnAs system. On that occasion I was also invited to lecture in Sapporo where I remember the pleasure of eating corn on the cob sold by a street vendor. In 1976, I was invited by H. Watanabe of Sendai to be a three-month visiting scholar of the Japanese Academy of Science, but I was only able to stay one month because I had to take up my new post in Oxford that autumn. I have had quite a few invitations to visit Japan, and I have enjoyed interacting with the scientists there. The Japanese have made a wonderful contribution to my fields of interest, and I have been a member of the Japanese Physical Society since about 1954.

The Japanese were interested in my work on magnetism in the early days and our work overlapped quite a bit. For example, Chikazumi was interested in my analysis of the factors that determine the shape of a B-H hysteresis loop, our discovery of cross-tie domain walls in thin films, and the damping factors that control the speed of domain-wall switching during a magnetization reversal ; he was in the process of writing a magnetism text book. Tom Kaplan, who was working with me in the late 1950's and early 1960's, discovered theoretically the possibility of spiral-spin configurations as a result of competitive exchange interactions ; the same theoretical discovery was made simultaneously in Japan and France, each from an analysis of the magnetic order in a different compound. We had a hard time convincing the theorists that the period of a spiral-spin configuration need not be commensurate with the crystal lattice. Tom Kaplan was interested in calculating the ground-state configuration ; as an experimentalist E. F. Bertaut of Grenoble was interested in deciphering the complex spin configurations revealed by his neutron-diffraction experiments. Both independently came up with the same mathematical formalism. There are moments when the time is ripe for certain ideas to emerge, and people working in different countries come up with similar solutions at the same time. Who gets the credit is important for the individual scientist, but it doesn't really matter for the progress of science.

More recently, the Japanese have been actively studying high-temperature superconductivity in the copper oxides and the colossal magnetoresistance in the manganese oxides. Professor Tokura has a large group growing single crystals, and we have made measurements on a few of his crystals. Mikio Takano, now a professor at the University of Kyoto, collaborated with me on the demonstration of a pressure-induced high-spin to low-spin transition at the Fe(IV) ions of CaFeO3.

AH : So the Japanese with whom you had contact were all in the university world ; it wasn't SONY or another corporation ?

JG : They were, for the most part, all in the university world or a research institute. But of course, SONY commercialized my work on cathodes for a rechargeable lithium-ion battery ; it was the basis of my selection as a Laureate of the 2001 Japan Prize. Because of this work, the Nippon Telephone and Telegraph Company sent Shigeto Okada to me and SONY sent me Yamada for a year.

AH : You allowed them to do that ?

JG : I have always been happy to receive good people who are funded by a home laboratory to which they will return. I don't have many sources of funding. David Nelson at the National Science Foundation has provided support for a post doc and a student and the Robert A. Welch Foundation has provided support for two students. I have had a little miscellaneous money from time to time that has helped me get through some lean times.

BBV : Does it cover equipment as well as students ?

JG : Not permanent equipment, but expendables.

BBV : You said you were interested in developing materials that would perform an engineering function. Do you go after research for industrial development ?

JG : No, I don't do industrial development ; but I do long-range targeted research. For example, when we developed LiFePO4 as a cathode material, we patented it and licensed it to the Hydro-Quebec Corporation. The people in Canada did the industrial development of how to fabricate a commercially viable material. Once I have identified a material that will perform a desired engineering function, I leave it to industry to commercialize it.

BBV : But if you have a problem-solving approach rather than an end-product approach, then the problem that you solve might be used for several end products rather than one. Which approach would you recommend for research productivity ?

JG : Research is productive not only when it produces a commercially viable end product, but also when it increases our understanding. Let me make a distinction between long-term targeted research and fundamental research that uncovers new phenomena or provides the understanding needed to know how to go about designing or searching for a new material for a specific engineering function. Examples of my targeted research efforts are the development of the ferrite memory core, of solid electrolytes, of battery cathodes, of materials for a solid oxide fuel cell, of wavelength-selective films for heating with solar energy, of a sole material for an amplifier tube that emits nearly 100 secondary electrons for every primary electron that strikes it, or our unsuccessful attempt to photo-electrolyze water with sunlight in one step rather than two. Yes, in the process of solving or evaluating these long-range targeted-research problems, we did more than obtain an end product ; we also learned a great deal about materials that not only increased our fundamental understanding, but also was to prove useful for solving another targeted-research problem. For example, our demonstration that a thin buffer layer can be used to prevent a chemical reaction between the electrolyte and the anode of a solid oxide fuel cell immediately suggests fabrication of a bilayer oxygen-permeable membrane for partial oxidation reactions. However, targeted research needs to be driven by a well-defined engineering need and a careful description of the engineering constraints expressed as a material "figure of merit" or some other set of criteria. If the engineer does not have a material in hand that can do his job, he can only turn to long-term targeted research to indicate the feasibility of the problem if not a solution to it. In my view, long-term targeted research is well served when there is a balance of fundamental research that can bring the discoveries needed to resurrect abandoned projects or to inspire new engineering concepts. I try to maintain such a balance in my research group. It would be unfair to ask a student to do a Ph.D. thesis involving an end product that is already under intensive development by industry.

I would also distinguish between the extrinsic and intrinsic properties of materials. For the most part, I have been interested in the intrinsic properties of a material whereas the industrial scientist is often concerned with how to optimize performance by changing its extrinsic properties such as shape, morphology, single-crystal versus polycrystal, or doping level. However, we did stabilize the capacity of the manganese-spinel cathodes by ball milling to create microdomains in our particles. Nevertheless, I am not a typical material scientist concerned with problems of fabrication and manufacture of materials that have already been identified as suitable for a particular end use. That's why I consider myself a solid-state scientist more than a materials scientist.

AH : But isn't the market the ultimate driver ?

JG : Engineering problems are driven by the market. But as a scientist, curiosity is also a driver ; one wants to understand the physical processes that govern the material properties we observe and exploit. Solving a problem in materials engineering may require addressing fundamental scientific questions. These are the problems that I prefer. For example, the market would like an electric car that performs as well as the cars we drive today. An engineering solution would be a direct methanol-air fuel cell. It would make possible an electric car powered by a liquid fuel just as the present-day internal-combustion engine is powered by gasoline. Conversion of the chemical energy in methanol to electric power in an electrochemical cell is a well-defined engineering problem, and the engineering constraints are defined by the performance of today's automobiles. However, to achieve adequate power requires identification of a solid H+-ion electrolyte and probably a better methanol-oxidation catalyst as well. Identification of materials that can perform these functions requires understanding of the processes that govern the phenomena of interest. Until these materials problems are solved, there is no point in proceeding with the engineering.

BBV : It seems to me that when you addressed the problem of an electric car in a 1978 paper, you didn't separate the electrolyte and electrode problems. You appeared to address both problems without separating them.

JG : The electrode and electrolyte problems are clearly separable ; each performs a different function. The anode must be an electronic conductor that catalyzes the oxidation of methanol, CH3OH, to carbon dioxide, CO2, and H+ ions whereas the electrolyte must be an electronic insulator that conducts protons. The cathode must be an electronic conductor that reduces the dioxygen molecule O2 to two oxide ions that combine with the H+ ions coming from the anode on the other side of the electrolyte. Carbon dioxide is the exhaust product at the anode, pure water is the exhaust product at the cathode. The entire package of electrodes and electrolyte must be considered together because the chemical potentials of the electrodes must be matched to the stability window of the electrolyte. With an H+-ion electrolyte, the cathode must be porous to allow escape of the water produced at the electrode-electrolyte interface. In a solid oxide fuel cell, an oxide-ion electrolyte allows use of a mixed oxide-ion/electronic conductor since there is no exhaust product emanating from the cathode/electrolyte interface in this case. Nevertheless, the chemical potentials of the electrodes must still lie within the stability window of the electrolyte.

BBV : Do you think you have contributed more to electrodes or to electrolytes ?

JG : I have contributed to both, but more to electrodes. My contribution to the lithium-ion battery has been the cathode, for example. I have made no contribution to either the liquid or the polymer electrolytes used in these rechargeable batteries. I have pioneered the use of a perovskite for the solid O2—ion electrolyte of a solid oxide fuel cell, but my more fundamental contribution was my early work on metallic perovskites that led the way to the use of these oxides as cathodes of the solid oxide fuel cell ; they include the purely metallic manganese oxides and the mixed oxide-ion/electronic conductors. All of the early fundamental work on metallic perovskites and my later work on perovskite oxide-ion electrolytes have provided a basis for selecting cathode and electrolyte materials, but the perovskite electrolyte faces stiff competition from oxides with the fluorite structure.

BBV : And what is your opinion about a specialized journal for the community of researchers working on solid-state ionics ?

JG : I have not been a strong advocate of specialized journals. On the other hand, solid-state ionics has become an important sub-field of electrochemistry, and I can understand the need for rapid publication of developmental results in a specialized journal. I would expect the more fundamental studies to be published in non-specialized journals. On the other hand, Physical Review and the Journal of the American Chemical Society cover so much territory that there was a need to create a Journal of Solid-state Chemistry. This journal has been quite successful, but I worry a bit that its emphasis may become too much on the preparation of new compounds and their structural characterization as new specialized journals are beginning to pull away papers on targeted research and the physics journals pull away the papers having a strong physics component such as those on high-temperature superconductivity and the colossal magnetoresistance.

When I went to Hawaii to receive the Olin Palladium Medal from The Electrochemical Society, I was struck by the tremendous impact of solid-state ionics on that society and on solid-state chemistry. The fact that people are making a great deal of money with the lithium-ion batteries and that the fuel cells are showing more commercial promise has brought financial support into the field. I expect the LiFePO4 cathode will stimulate the field further. It is cheap and environmentally benign, so it may become competitive in large batteries. I can't claim to have designed it ; but I did have an idea where to go fishing. In any case, the field of solid-state ionics is growing, and journals that cater to the field will undoubtedly prosper.

BBV : One more factual question. You have had a lot of students over the years. Did you teach ? Did you have to teach ? What difficulties did you have with teaching ?

JG : Lincoln Laboratory was a Research & Development facility separate from the MIT campus. During my 24 years there, I had only one Masters and two Ph.D. students and I only gave a short series of lectures, never a formal course.

The system at Oxford is totally different from that of a U. S. university. Students come up to Oxford to read Chemistry with two years of Advanced Level science courses that are equivalent roughly to the first two years in a U. S. college. Chemistry students were selected by each College by the Dons of that College who coached them for three years for a career-making final examination. The Inorganic Chemistry Laboratory provided a mandatory Practical Course and a series of 8-lecture courses that were optional, but generally provided material essential for the big final examination. I gave lectures on solid-state topics that were not necessarily covered in their finals, so the half-life of the attendance in my classes tended to be fairly short. After the final, the students did a fourth year of research for their undergraduate degree. My principal contribution to undergraduate teaching was probably the supervision I gave to those who chose to do this research year with me.

At Texas I am required to teach two graduate courses a year. I have also taught undergraduate courses in Mechanical Engineering and Electrical Engineering. I prefer teaching the graduate courses. Of course, my hope is that considerable learning occurs in the course of completing a Ph.D. with me. Those who have absorbed the most are a few excellent students and the better post docs.

AH : I would like to run with the instrument ball for a bit. How do you see the development of instrumentation having an impact on your work ?

JG : That 's a big question.

AH : Maybe you could start by saying what was available in 1951 when you started.

JG : Let me restrict myself to the field of transition-metal oxides. In 1951, ceramic materials were made mostly with high-temperature powder-metallurgy techniques or hydrothermal synthesis. The use of organometallic precursors to lower firing temperatures was a novel idea. Physicists wanted single crystals. The growth of single-crystal magnetite was a major undertaking and achievement. Zone refining of germanium to achieve single crystals of high purity was being developed ; oxide crystals were grown primarily by the Czochralski technique of pulling a seed crystal from the melt. Crystal growth from a flux was just being developed as an art. Now we have an image furnace with which we are able to grow oxygen-stoichiometric oxide crystals of high purity. In 1951, chemical characterization rarely included the analysis of oxygen stoichiometry ; thermal-analysis instruments were not commercially available, and mass spectrometers were used. High-pressure synthesis was carried out in a few laboratories, but techniques for applying high oxygen pressures were not yet developed. Thin films were prepared by primitive sputtering machines. Since those days, soft chemistry is widely used for synthesis and more complete chemical characterization of ceramic materials has become normative. Films are now deposited by a variety of techniques, many of which were not then available. Laser deposition is an example.

In 1951, the electron microscope did not have the high resolution that is available today. The first direct observation of a dislocation was made at that time. The principal tool for structure determination was X-ray diffraction, but analysis of the data was laborious. The first observation of antiferromagnetic order by neutron diffraction was made at that time. Neutron-diffraction and scattering measurements have now become sophisticated and fundamental tools in solid-state science. The advent of synchrotron radiation and pulsed neutron techniques have enabled direct observation of structure at short time scales, which is opening a whole new field of study.

Various spectroscopies were available in 1951, but photoelectron spectroscopy had not yet been developed and nuclear magnetic resonance was in its infancy. Mössbauer spectroscopy and the laser had not yet been imagined. A principal tool at that time was electron paramagnetic resonance. Impedance spectroscopy for measuring the ionic conductivity of electrolytes was not commercially available.

The superconducting magnet and the SQUID magnetometer did not exist. To obtain a magnetizing field of 50 kOe was a big-science project. The vibrating-sample magnetometer was developed at Lincoln Laboratory by Simon Foner in the late 1950s, and Don Smith of my group developed a vibrating-coil magnetometer that allowed us to do magnetic measurements under high pressure. However, the measurement of physical properties under high pressure is still restricted to a few laboratories.

The development of affordable, powerful computers for data collection and analysis has transformed the accuracy and speed with which measurements can be taken. It has quite revolutionized the experimental laboratory.

AH : So what was the infrastructure of the Lincoln Laboratory, of Oxford, and here in Texas ?

JG : The ceramics laboratory that I inherited at Lincoln Laboratory had high-temperature furnaces, a hand press, a hood, a powder x-ray diffractometer, and chemical benches. We were in the Digital Computer Division ; the Solid-state Division was much better equipped, but our access to their facilities was essentially non-existent as each person in that division had an agenda of their own. However, their mass spectrometer was a service facility to which we had access. We made routine transport measurements on the samples we prepared and characterized structurally. I developed a good working relationship with Jim Kafalas who had developed a high-pressure belt apparatus and was looking for something interesting to do with it. With him, John Longo and I demonstrated the relationship between bond-length mismatch in the perovskites and the hexagonal polytypes. Kafalas also developed high-pressure equipment for magnetic measurements with the vibrating-coil magnetometer. We used pressure to change from one polytype to another and to transform from high-spin to low-spin magnetic configurations. I came to appreciate the pressure variable as an extremely useful research tool. We also acquired sputtering equipment for the preparation of wavelength-selective films and for our MgO-Au composite film. At Lincoln, I relied primarily on developing chemical strategies that could provide important information with the measurement facilities at my disposal. I suppose that is why Oxford considered me as a solid-state chemist.

At Oxford, there was little money for equipment in the Inorganic Chemistry Laboratory. I was not given any significant start-up funding, so I relied on the availability of x-ray diffraction, facilities for chemical analysis, a glass-blowing shop and an electronics shop. I acquired furnaces for my own synthesis needs, the means to make impedance spectroscopy and routine electrochemical measurements as well as the optical equipment needed to study photo-electrolysis. The laboratory also had photoelectron spectroscopy and nuclear magnetic resonance, and I did some collaborations with those working with these instruments. Outdated equipment for electron paramagnetic resonance was put into use in the one systematic catalytic study I made on the phosphopolymolybdates. One group in the laboratory was given a second-hand vibrating-sample magnetometer that proved more frustrating than useful. At Oxford, I concentrated on ionic transport, battery cathodes, and photo-electrolysis ; I did relatively little work on the transition from localized to itinerant electronic behavior except to show that hybridization of the d electrons of a transition-metal atom with 6s2 core electrons of a counter cation could cause a localized electronic configuration to become delocalized.

AH : You just didn't have the infrastructure for magnetic measurements ? You couldn't have gone off and used magnetometers elsewhere in the university ?

JG : I suppose I could have developed a collaboration with someone in the Clarendon, but I was busy with another agenda.

AH : Were you a member of a College ?

JG : Yes, St. Catherine's.

AH : And were you able to build interdisciplinary connections through your college ?

JG : It should have been possible in principle, but it didn't turn out to be practical. When I arrived at the University of Texas at Austin, I was given $300 K as a start-up package and an empty room. Professor Hugo Steinfink had an x-ray diffraction laboratory that he has generously shared. He also had a high-pressure belt apparatus in disrepair that was a copy of the one developed by Kafalas at Lincoln Laboratory. I also had access to electron microscopes. With the help of post docs, I built up first my chemical facilities, including thermal analysis, impedance spectroscopy, a dry box, atomic absorption spectroscopy, an arbin battery tester, and equipment for routine electrochemical measurements. We do our own chemical analysis. We later added a SQUID magnetometer and an infrared image furnace for growing single crystals. J.-S. Zhou has developed measurement of transport and magnetic properties under pressure as well as specific-heat and thermal-conductivity measurements. Keqin Huang also developed apparatus for oxygen-permeation measurements. With our own synthetic facilities, we can develop our experimental strategies without relying on others. If you rely on getting crystals or samples from someone else, they have already done all the routine measurements on it. With only a special measurement technique, you must rely on collaborations. If you want to understand how physical properties vary with changing chemistry, you have to be able to make your own materials. I have always thought that was critical.

BBV : You never rely on others ?

JG : Occasionally we have received crystals that we could not prepare when others wanted us to collaborate by making measurements under pressure ; but for the most part we rely on our own samples designed to carry out a particular experimental strategy. People have also come to me for help in the interpretation of their data.

BBV : When you were at Oxford, did you have contact with other universities in England and Europe ?

JG : Yes. I went to Scotland to examine undergraduates. I also examined D. Phil. and Thèse d'Etat candidates in universities of England and France. I interacted some with Brian Steele of Imperial College, London, and his colleagues ; they were interested in the solid oxide fuel cell. At Cambridge, Sir Nevil Mott was interested in the transition from localized to itinerant electronic behavior, and Greenwood at Leeds was a solid-state chemist who did Mössbauer spectroscopy. At AERE Harwell, I collaborated in a European project with a Danish group on the development of lithium-ion batteries and an unsuccessful attempt to realize a methanol-air fuel cell. In France, the people in Montpellier were interested to interact on the subject of solid proton conductors, and I wrote a long review on iron oxides with Charles Gleitzer of Nancy. Hagenmuller sent me a young man from Bordeaux to work with me for over a year, and Jean Rouxel of Nantes sent me someone for six months. Pepe Fontcuberta came for a summer from Barcelona, and I had some interactions with electrochemists in Madrid. I was also asked to give a series of lectures at different universities in Norway on one occasion and in Germany on another. Emanuel Kaldish of the ETH in Switzerland arranged conferences for young people of the underdeveloped countries in Erice in Sicily, in New Delhi in India, in Cairo and Alexandria in Egypt. I also went to India, a country I have visited several times, as the Raman visiting professor.

BBV : And having this experience in Europe and the United States, do you have any idea why materials science generally never started in Europe as here although they have had a great tradition of solid-state chemistry ?

JG : The brief answer is our mission oriented defense and space efforts. England had a strong tradition in metallurgy and solid-state physics out of which grew a magnificent contribution to physical metallurgy. France and Holland had a strong tradition in magnetism out of which grew, secretly during World War II, the development of the ferrospinels that proved critical not only for the memory of the digital computer, but also for microwave devices. In this country, the development of the transistor was also seminal. Work on the nuclear bomb in Los Alamos and on radar at the Radiation Laboratory of MIT during the 1940s alerted the military people to the power of interdisciplinary research ; faced with the challenges of the Cold War, they encouraged this type of research in places like the Bell Telephone Laboratories, the Lawrence Livermore Laboratories, and the MIT Lincoln Laboratory. The military people also encouraged NSF to establish interdisciplinary materials laboratories in several of our universities. Bell Telephone had a monopoly in the early days, which enabled it to plough back its excess profits into research. In the 1950s and 1960s, the Bell Telephone Laboratories were the dominant player in the development of materials science both because of the changing nature of their business and because of large government contracts to develop military and space hardware. The development of fiber optics is an example of how their mission as a communications company kept them involved with materials problems. With the completion of the SAGE system at Lincoln Laboratory, IBM was chosen to manufacture the digital computers for it. The government allowed IBM to add 10% to the cost for product improvement ; they used these funds to build their Yorktown Heights research facility. Kennedy's decision to send a man to the moon within a decade added another set of materials problems that needed to be solved. Moreover, polymers were proving to be a great commercial success. It was the creation of mission-oriented laboratories and the technologies they spawned that challenged the traditional academic disciplines. Technical knowledge was being created rapidly outside of academia ; the traditional Metallurgy and Electrical Engineering departments were forced to expand their definition so as to include the new technologies and to prepare graduates for careers in these new types of laboratories. France under De Gaulle chose to become independent in military and space hardware, so a strong materials science effort was initiated in France under his leadership.

Also, during and following World War II, companies like DuPont de Nemours and Corning Glass had lively interdisciplinary research groups that produced numerous new products. It is unfortunate that most of these industrial facilities are now starved of corporate funds and must compete for government funding of their long-range targeted research.

The chemistry departments in the U. S. and Great Britain have been slow to build up solid-state chemistry as an interdisciplinary subject ; the inorganic chemistry community has been dominated by organometallic chemistry. The solid-state chemists have been incorporated into the materials science and engineering programs in the U. S. Only now as the engineers look for components at the molecular level are the chemistry departments becoming more involved. France, Holland, and Japan have recognized the importance of solid-state chemistry, but of course their development came only after a period of reconstruction following World War II. Russia has emphasized materials science as it, too, had military and space missions. Germany had a longer period of reconstruction, and their mission-oriented laboratories have all been industrial. The Max Planck Institutes are not mission oriented in the same way as the Department of Defense and Energy in this country, so materials science as we know it here has developed slowly in Germany.

Identity with a clear mission is important not only for the development of materials science, but also for the vitality of an interdisciplinary laboratory. For example, the MIT Lincoln Laboratory was the key player in the development of the digital computer during the 1950s. That success reflected a clear mission. When that mission was completed, the leadership lost its vision for further development of the digital computer, and therefore its most talented experienced staff in this field went elsewhere. By the end of the decade, it was clear that the future of the computer lay in making all the components smaller. Microelectronics was the next logical step. However, the Head of Lincoln Laboratory and the MIT administration did not wish to compete with industry in this next phase, so Ken Olsen took a group of computer engineers from the laboratory and founded the Digital Equipment Corporation. Others were given opportunities for leadership in several corporations. A few months later, a group of engineers who stayed with the laboratory had built a small computer that would be affordable by a single research unit. Wes Clark brought it down to the National Institute of Health where he solved in one afternoon a problem they had been working on for months. It was the first demonstration of the efficacy of a small computer. When he returned triumphant the next day, the Head of Lincoln Laboratory announced, "There will be no wet scientists in this laboratory." Consequently this innovative and motivated group left the laboratory.

On the other hand, there is also a strong cultural component. When I went to England, I found that members of the Inorganic Chemistry Laboratory downgraded targeted research ; "pure" research was only curiosity driven ! Moreover, I was astonished when a leader of a chemical industry told me they were hiring few people with a D. Phil degree because these people were only interested in "pure" research. This dichotomy between curiosity-driven and targeted research in a country where class distinctions are so important has, in my view, been a great impediment to Britain's development of materials science as we know it. In France, on the other hand, the Grandes Ecoles have been developing engineers for leadership posts. A British colleague acting as Director of the Institut Laue Langevin (ILL) laboratory in Grenoble told me that the British equipment salesmen knew everything about sales, but little about the performance of the equipment they were selling whereas the French salesmen were good engineers and could answer the specific questions posed by the experimental customer. France's delay in developing a strong presence in the field of materials science was largely due to the period of recuperation following World War II. Establishing the CNRS laboratories gave science a strong boost. However, the CNRS laboratories, like the Max Planck Institutes in Germany, tend to be built around an individual with a specific technique or area of specialization. They are rarely mission oriented unless they receive supplemental financial support from industry or a mission-oriented government agency. Nevertheless, they do build into the university structure the means to develop interdisciplinarity and thus to bid for targeted-research funds. Without the infrastructure of research scientists and equipment that the CNRS provides, the individual university professor with four or five students is isolated and generally unable to compete with larger groups in targeted research unless it is quite long-range.

BBV : Has it been possible for the European to do away with national identity ?

JG : There are now numerous large-science projects that are European rather than national, and science itself has an international character. However, cultural differences and national identities persist. The ILL in Grenoble, for example, is jointly supported by England, France, and Germany. The Director is rotated every three years between the three countries. Nevertheless, the groups from the different countries each bring a different style, sometimes to the irritation of one another. Also, Brussels funds projects that are required to be multinational. I had one with the French and Danes on batteries and had just negotiated another on fuel cells with the French and Germans when I returned to the U. S. These projects tend to be strategic, long-range, targeted research addressing fundamental materials problems. With the globalization of industry and a NATO alliance, the national barriers to cooperation are breaking down, but a national identity and competition for a market-share will accompany their European identity.

AH : You have just outlined the situation in the U. S., Britain, France, and Germany. Do you have any sense of how Japan fits into this process, or is that asking too much ?

JG : No. Japan has done a remarkable job in the area of materials science. The Japanese have not had a military mission, but they have realized their need to compete for external, high-technology markets. Therefore, they have set up mission-oriented government laboratories in support of their industries. They have also established interdisciplinary laboratories in association with universities ; these undertake the longer-range kinds of research that interests me. The large Tsukaba consortium is an interesting experiment that is well suited to the Japanese style. Japan is a homogenous society with a strong national identity ; its people strive to prove themselves after their defeat in World War II. They have built up an excellent cadre of scientists and engineers that is well supported with a sophisticated infrastructure of equipment ; and they make excellent measurements and theory. In my areas of interest, the Japanese are leading competitors and contributors. I am also happy that there are influential voices in Japan that are aware of our need to find a balance between nature's bounty and its exploitation by man.

AH : Now you are emphasizing the funding for equipment and the design of new instruments. I had the impression when you were talking about your own experience that you were de-emphasizing the role of instrumentation.

JG : I didn't mean to leave that impression. I emphasized the importance of being able to make your own materials if you wish to develop a chemical experimental strategy in materials science. I have used, for the most part, quite standard physical measurements because of the limitations of my own situation. However, where it was possible for me to develop instrumentation, I have supported it. Our most innovative instrumental developments have been in the area of high pressure. With Jim Kafalas, I used high-pressure synthesis of metastable phases and the measurement of magnetic properties under high pressure. Unfortunately my program at Lincoln Laboratory was terminated before I could fully exploit our facility. However, we did enough to attract J.-S. Zhou to Texas, and with him I have used pressure not only for the synthesis of metastable phases, but also as a variable to probe new electronic states in solids and transitions into or out of these states without changing the chemistry. Measurements made at the major national facilities are followed carefully ; they guide our strategies. I have already mentioned a number of these techniques.

AH : Can you point to instrumentation that has actually changed your trajectory, your research strategy, because you can now do things that you couldn't do before ?

JG : My research trajectory has been determined by questions I wanted to answer or by engineering challenges ; but of course the strategies we choose depend not only on our questions, but also on the facilities at our disposal. The advent of neutron diffraction, which allowed precise observation of the positions of lighter atoms such as oxygen as well as of ordered spin configurations, has certainly motivated much of my research even if the predictions made were to be confirmed experimentally by those with access to neutron diffraction. Similarly, the direct observation with high-resolution electron microscopy of extended defects such as shear planes and charge-density waves stimulated my research and clarified my view of solids. Access to high pressures has also allowed me to develop experimental strategies that have proven fruitful in my studies of phase transitions, especially high-spin to low-spin transitions and the crossover from localized to itinerant electronic behavior. I have made occasional use of Mössbauer spectroscopy. The development of the vibrating-sample, the vibrating-coil, and the SQUID magnetometer have played a central role. I should also mention that superconducting magnets have given us access to 50 kOe magnetizing fields that were, in 1951, restricted to a few centers. I have made less use of the laser, but the ability to deposit high quality films has been used from time to time. The ability to grow high-quality oxide single crystals with the IR image furnace has also shaped my strategies. Of course, we should not overlook the influence of computers on the automation of our experiments. The commercial availability of such instruments as Thermal Analysis or the Solartron have also enabled me to move into fields without having to build my own apparatus. Photoelectron spectroscopy is a technique that I have happily used whenever I could get access to it with a collaborative partner. The opportunity to find collaborators can be a great determinant to one's research trajectory.

AH : You have just told us about Japan. Do your Chinese colleagues give you any sense of what is going on in China ? Have you been to China ?

JG : Yes, I had the opportunity to make a fairly extensive visit to China a few years ago, and my colleague J.-S. Zhou keeps contacts there. The first observation is that China is changing rapidly. Under Mao Zedong the lid was on everything. Under Deng, people were allowed to make money, but politics remained tightly controlled. Under the present regime, people are more free to think as well as to make money, and the energies and imagination of the people has been unleashed, but within a nationalistic view and still restricted framework. The people value education. Western high-technology industries have moved their production facilities to China to have access to skilled, cheap labor. As a result, they are transferring manufacturing technical and managerial skills to China. The present government has decided it needs to compete with the world in high technology, so it is in the process of establishing research centers that are well-equipped with the latest tools. They have a big pool of educated talent, and they are beginning to bring back from the West with big salaries those they believe can lead their scientific as well as their technical development. China wishes to emerge as one of the leading countries in the science and technology arena. It is too early to tell how their investment will pay off. For the last 50 years, India has poured a substantial percentage of their gross national product into science and into technical education, but the return to the country has not been commensurate with the investment despite the emergence of excellent Indian scientists, many of whom work in the West. The political culture is extremely important.

AH : Have you seen the laboratories in China ?

JG : I was in China before the decisions were made to put a big investment into instrumentation in science research laboratories. I had no access to their military laboratories ; these were undoubtedly equipped first. At the time of my visit, researchers in the universities were not well equipped. Now the computer network and the cell telephones are as prevalent in the big cities as anywhere in the West.

In the last 30 years there has been a steady increase in the number of Asian students that come to this country for higher education. Many of them stay and make a wonderful contribution to our high-technology corporations and our schools. When I was younger, I was moved to wonder how the U. S. could best help the underdeveloped world to come into the technological age. I thought then we should be helping to set up research laboratories there, which is why I considered going to Iran in 1975. I have now come to realize that providing the opportunity to come to our graduate schools and the transfer of manufacturing facilities to their countries is a much more efficient method of providing help. But the political culture has to be right. It breaks your heart to see the conditions under which so many people struggle for life. Why hasn't Mexico taken off and done something more ? Why does a country like Argentina have 30% unemployment today ? It's sad. It shouldn't be. It shouldn't be like that.

Fin de l'enregistrement.

Pour citer l'entretien :

« Entretien avec John B. Goodenough », par Bernadette Bensaude et Arne Hessenbruch, mai 2001, Sciences : histoire orale, /spip.php ?article28.

Pour citer l'entretien :

« Entretien avec John B. Goodenough », par Bernadette Bensaude-Vincent et Arne Hessenbruch, mai 2001, Sciences : histoire orale, https://sho.spip.espci.fr/spip.php?article28.

Lieu : University of Texas, Austin (USA).

Support : enregistrement disque.

Transcription : Bernadette Bensaude-Vincent et Arne Hessenbruch.

Édition en ligne : Pierre Teissier