Diffusion Mechanisms in Transition-Metal Oxides.

摘要

Results are presented for cation self-diffusion in Cu sub 2 O and Cr sub 2 O sub 3 as a function of temperature and deviation from stoichiometry. A defect model for Cu sub 2 O involving neutral and singly charged copper vacancies, electron holes, and singly charged oxygen-interstitial ions is developed and fit to the tracer-diffusion data, the electrical-conductivity data, and the stoichiometry data, yielding concentrations and mobilities of these defects. The diffusion results for Cr sub 2 O sub 3 single crystals indicate that cation self-diffusion takes place by triply charged vacancies and that previous diffusion results for polycrystalline Cr sub 2 O sub 3 are dominated by grain-boundary diffusion. (ERA citation 09:006212)