1447. ---------------. [HOFER, L. J. E., COHN, E. M., AND PEEBLES, W. C.] Isothermal Decomposition of Nickel Carbide. Jour. Phys. and Colloid Chem., vol. 54, No. 8, November 1950, pp. 1161-1169; Chem. Abs., vol. 45, 1951, p. 1850.

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Literature Abstracts

Thermal stability of Ni₃C was studied magnetically and by X-ray diffraction 320°-355° on a fully carburized and on an almost fully carburized sample. An induction period precedes the decomposition. This period is analogous to that found for the decomposition of austenite. There is no detectable structural change in the carbide during the induction period. The carbide decomposed into free metal and free C without intermediate formation of a lower carbide. Shortening the induction period by temporary overheating did not affect the zero-order rate of the decomposition, except when the normal induction period was completely suppressed. In that case, the zero-order rate was approximately doubled. In the range 70-10% Ni₂C, the decomposition rate was constant; hence, the reaction was of apparent zero order in that range. Empirical-activation energies were found for the induction periods and quasi-zero-order range of decomposition of both the fully carburized carbide and the almost fully carburized carbide.

HOFER, L. J. E., PEEBLES, W. C., AND BEAN, E. H. X-Ray Diffraction Studies of the Action of Carbon Monoxide on Cobalt-Thoria-Kieselguhr Catalysts. II. See abs. 1442.