ABSTRACTS 721

atomique constante, &pares par n couches de carbone. Le nombre n’est Cgal a 2 dans un coke prepare & 1000°. Le traitement thermique de preparation des carbones B des temperatures croissantes, fait croitre n ind~finiment de sorte que f’affinid pour le sodium disparait compI~ment apres la ~aphitation.

76. Hydrogen inhibition of the graphite-water vapor reaction* G. L, Montet and G. E. Myers (Argonne National Laboratory, Argonne, Illinois). Preliminary results of an

electron microscopic investigation of the graphite-water vapor reaction indicate that even very low concentrations of hydrogen inhibit the reaction to a great extent. It is hoped that some insight into the mechanism of this reaction may be gained by studying both the uninhibited and inhibited reaction.

*Based on work performed under the auspices of the U.S. Atomic Energy Commission.

77. Etude de l’action de l’eau SW un graphite F. Lang et Y. LaFargue (Centre d’Etudes Nucleaires de Sac& CEA, Gzfsur-Yvette, Seine et Oise, France).

On peut distinguer trois types d’action: (I) Adsorption physique avec condensation capillaire; (2) Ad- sorption chimique sur sifftrents sites, en nombre limid et caracdrises par un niveau Cnergetique en relation avec leur reactivite. Nous avons &value le nombre d’atomes Ies constituant; (3) Reaction chim- ique d’oxydation. Ces trois processus sont simultanement presents B 25°C.

78. The reaction of carbon with carbon dioxide and its self-diffusion E. S. Golovina, V. S. Chapiigina and L. L. Kotova (The G. M. Krzh~~anousk~y Institute of Energetics,

‘~oscov~, USSR). The seIf-diffusion of carbon caused by the reaction of carbon with carbon dioxide on the phase boundary has been shown by using the radiocarbon Ci4 and method of radioautography. The photopyrometer method was used for determination of the temperature distribution in such carbon body. The self-diffusion coefficient of carbon has been estimated on the basis of these experimental results.

79. Topographical studies of gasification of pure and impure carbonaceous materials K. Adair, E. N. Boult, E. M. Freeman and H. Marsh (Northern Coke Research Lab~ato~s, Schootof Chem-

istry, The University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, U.K.). Topographical studies of gasification of graphite (cf. Hennig, Thomas) have proved significant. But, paracrystalline materials are difficult to replicate or examine by optical microscopy. Now, the advent of Stereoscanmicroscopy has made possible the direct study of surfaces of carbons, (cokes), films, etc., and the changes produced on gasification. The mode of action of catalytic impurities is of particular relevance. It is proposed to illustrate and discuss the complexity of certain changes, in particular those produced using different catalytic impurities.

80. A mass spectrometric study of the carbonisation of organic molecules S. Evans and H. Marsh (Northern Coke Research Laboratories, School of Chemistry, The University of New-

castle upon Tyne, Newcastle upon Tyne NEZ ?RU, U.K.). A mass spectrometric study, using an AEI MS9, is made of mesophase and liquid phases produced on carbonising single organic molecules, simpIe mix- tures of organic molecules, and solutions of organic molecuies in meta-quinquephenyl. Some fifty systems have been examined. Molecular weights, up to about 800 are reported indicating modes of con- densation to give the ‘solid material’ which is the precursor of cokes and graphites. Atomic hydrogen and atomic chlorine are used to depolymerise the ‘solid material’ to give further information.

V. STRUCTURAL STUDIES

81. Structural aspects of graphitization: advances and unsolved problems (Plenary Lecture). W. Ruland (European Research Associates, Union Carbide, BruxeZZes 18, Belgium).

82. X-ray determination of the structure of noncrystalline carbons S. L. Strong (Union Carbide Corporation, Carbon Products fiction, Parma Technicul Center, Check,

Ohio). Radial distribution functions have been obtained for several forms of noncrystalline carbon and are analyzed in terms of a model for the structure of these carbons. The parameters of the model employed, although related to the conventional parameters, such as L, and L,, are defined in terms of