Diffusion of Palladium in Copper and Silver

Abstract

The diffusion of palladium in single crystals of copper and silver has been measured by the tracer-sectioning technique. The results are ${D}_{\mathrm{Pd}\ensuremath{\rightarrow}\mathrm{Cu}}={1.71}_{\ensuremath{-}0.21}^{+0.23}\mathrm{exp}[\ensuremath{-}\frac{(54370\ifmmode\pm\else\textpm\fi{}300)}{\mathrm{RT}}] {\mathrm{cm}}^{2}/sec,$ and ${D}_{\mathrm{Pd}\ensuremath{\rightarrow}\mathrm{Ag}}={9.57}_{\ensuremath{-}1.37}^{+1.63}\mathrm{exp}[\ensuremath{-}\frac{56750\ifmmode\pm\else\textpm\fi{}300)}{\mathrm{RT}}] {\mathrm{cm}}^{2}/sec.$ The difference between the activation energies for Pd diffusion and self-diffusion in copper and silver is in only qualitative agreement with the theories of Lazarus and LeClaire. Correlation factors for palladium diffusion in silver are calculated using Lidiard's theory and the data on silver diffusion in palladium-silver alloys by Nachtrieb et al. From these correlation factors and Manning's theory, it is shown that palladium atoms repel vacancies in silver. This is in disagreement with the quenching studies of Hamaguchi.