2276. MICHEL, A., BERNIER, R., AND LECLERC, G. [Thermomagnetic Study of Fischer Catalyst Containing Nickel.] Jour. chim. phys., vol. 47, 1950, pp. 269-273; Chem. Abs., vol. 44, 1950, p. 7638. Results of a thermomagnetic and structural study of Ni catalysts. An intimate relation existed between the catalytic activity of Ni and the crystal size. The most active catalysts possessed a certain type of magnetization-temperature curve that was correlated by means of X-rays with the crystal size. Under certain conditions of catalysis, the Ni catalyst was transformed into a paramagnetic hexagonal carbide of Ni. In the initial stages of catalysis the C formed a solid solution with the Ni and expanded the face-centered cubic structure. The lowering of the Curie point of active Ni catalysts after use for 100 hr. suggested that small amounts of C were present in these catalysts. |