Criterions for the Assumptions of Thermal Equilibrium of Interstitial Atoms and of Vacancies in Dissociative Diffusion

Abstract

Basic equations for dissociative diffusion are non-linear. To solve them analytically, it is usual way to assume that interstitial atoms or vacancies are in thermal equilibrium. To obtain a criterion for the assumption, the basic equations are approximated by linear equations when concentrations of substitutional atoms, interstitial atoms and vacancies come near to their thermal equilibrium values. It is found that the thermal equilibrium concentration as well as the diffusion constant is an important factor for the criterion.