INVESTIGATIONS OF DIFFUSION OF S-35 RADIOISOTOPE IN BETA-NI3S2 POLYCRYSTALS

The diffusion of S-35 radioisotope in beta-Ni3S2 polycrystals was stud ied at temperatures ranging from 848 K to 893 K and at Sulphur vapour pressure interval (5.6 x 10(-6)-3.2 x 10(-4)) Pa. The autoradigraphy a nd the tracer sectioning method were used. It was found, that the bulk diffusion is the main process of sulphur transport. The activation en ergy of the diffusion equals (190 +/- 10) kJ mol(-1). Under the condit ions used in the experiments the dominant anionic point defects are si ngle-ionized vacancies and quasi-free electrons. (C) 1997 Elsevier Sci ence Ltd.