Permissible values of vacancy flow factor and ratio of impurity diffusion coefficient to solvent self-diffusion coefficient in b.c.c. metals

Abstract

Under conditions in which the jump-frequency ratio must be positive from a physical viewpoint, the permissible relationship between the vacancy flow factor G and the ratio D ₂/D ₀ of impurity diffusion coefficient to solvent self-diffusion coefficient in b.c.c. metals is examined. In the diagram showing G versus D ₂/D ₀, the permissible zones are determined for two jump-frequency models. This result enables the use of experimental data to decide which model is appropriate in any particular diffusion system.