Interdiffusion Coefficients in ε Phase of the Ag-Zn system

Abstract

In the temperature range 583 to 673 K interdiffusion coefficients were determined in the concentration range about 74 at%Zn to the ε⁄η phase boundary.
Concentration dependence of the coefficients underwent a change at about 83 at%Zn. The coefficients at solidus temperature of the ε phase, \Tilde{D}_Tm, were constantly kept up to 82 at%Zn, where the following equation was held.
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At composition of about 82 at%Zn Straalsund and Masson previously found an irregular change of zinc activity and attributed the activity change to an overlap of the Fermi surface across the Brillouin Zone. Because characteristic changes of the interdiffusion coefficient and the activity appeared at the same composition, the interdiffusion coefficient might be also affected by the zone overlap.
From marker experiments it was estimated that the ratio of intrinsic diffusivity of zinc to that of silver were twenty to fourty and trended to decrease with increasing zinc content.