Two- to ten-nanometer thick polycrystalline Pd films were prepared on the (111) surface of Ag single crystals and investigations of the Ag diffusion along Pd grain boundaries were carried out by using the Hwang–Balluffi method. The samples were monitored by Auger electron spectroscopy during isothermal heat treatment at 438 to 563K. Using plausible simplifying assumptions, the activation energy of the product of the grain boundary diffusion coefficient and k′ (k′ = cs/cg), where cs and cg were the surface and grain boundary concentrations, respectively was calculated (0.99eV) from the evaluated saturation coefficients of the surface accumulation. This energy, for a weak temperature-dependence of k′, was approximately equal to the activation energy for the grain-boundary diffusion.

Silver Grain Boundary Diffusion in Pd. Z.Balogh, Z.Erdélyi, D.L.Beke, A.Portavoce, C.Girardeaux, J.Bernardini, A.Rolland: Applied Surface Science, 2009, 255[9], 4844-7