Effect of Antimony Impurity on Self-Diffusion of Silver

Coefficients for diffusion of ${\mathrm{Ag}}^{110}$ into single crystals of alpha silver antimony were measured as a function of temperature and concentration, over the range 550-900°C and 0-1½% antimony concentration. In addition, a number of measurements were made of the diffusion of ${\mathrm{Sb}}^{124}$ into similar alloys. The activation energy for silver self-diffusion was found to decrease by 1½ kcal per percent added antimony. Effects of impurity were appreciably less for solute diffusion than for solvent diffusion. The results are in qualitative agreement with theories of Overhauser and Lazarus, and indicate that effects due to changes in vacancy concentration are smaller than those resulting from changes in mobility energy.