Characterization of the defects responsible for the precipitation of silver from dilute PbAg solid solutions

Abstract

The diffusion coefficients of silver ( D ∗ ) have been measured during its precipitation from dilute PbAg solid solutions (92 × 10 −6 at/at and 184 × 10 −6 at/at) by using 110Ag radiotracer between 327 and 363 K. The diffusion activation energy Q D ∗ = 49.4 kJ/mol is smaller than the diffusion activation energy ( Q D = 60kJ/mol) of silver in pure lead but is in fair agreement with the activation energy for precipitation of silver previously measured by the authors ( E a = 50 kJ/mol). Evidence that the (PbAg) pair is the defect responsible on the one hand for silver migration during the precipitation in these dilute alloys and on the other hand for silver diffusion in pure lead and lead-silver solid solutions is reviewed.