Self-diffusion in cr₂o₃I. Chromium diffusion in single crystals

Abstract

Abstract Chromium self-diffusion coefficients in chromia (Cr2O3) single crystals were determined by both ion implantation and thick-film methods, using the 54Cr and 50Cr isotopes. The concentration profiles were established by secondary-ion mass spectrometry, and the diffusion coefficients were computed using a solution of Fick's law taking into account evaporation and exchange at the surface. Chromium diffusion was studied as a function of temperature T and oxygen pressure Po2. Both methods lead to diffusion coefficients of the same order of magnitude. The diffusion coefficients are lower than those given in the literature and do not depend on the oxygen pressure; they are well described by the relation