Diffusion studies in Ag-Zn alloys

Abstract

Diffusion studies were made in the alpha and beta phases of the silver-zinc system at 600°C with vapor-solid and solid-solid diffusion couples in order to determine intrinsic diffusion coefficients and interdiffusion coefficients. Intrinsic diffusion coefficients, DZn and DAg, determined experimentally for bothα andβ alloys, were compared with those predicted from the models of Darken, Manning, and Dayananda with the aid of thermodynamic and single crystal tracer diffusion data. The experimental values of Dzn were close to those predicted by the models of Darken and Manning, while the experimental DAg values were higher than those determined by both models. The experimental values of the ratio, DZn/DAg, were found to be lower than those predicted by either Darken’s or Manning’s relations. Also, Dayananda’s model was found to be inapplicable with the available tracer diffusion data. This disagreement is considered to reflect the inadequacy of the single crystal tracer diffusivities in the analysis of intrinsic diffusion in polycrystalline Ag-Zn alloys.