Determination of Grain Boundary Diffusion Coefficients in C-regime byHwang-Balluffi method: Silver Diffusion in Pd

摘要

Diffusion controlled processes play a crucial role in the degradation of technicalmaterials. At low temperatures the most significant of them is the diffusion along grainboundaries. In thin film geometry one of the best methods for determining the grain boundary (GB)diffusion coefficient of an impurity element is the Hwang-Balluffi method, in which a surfacesensitive technique is used to follow the surface accumulation kinetics. Results of grain boundarydiffusion measurements, carried out in our laboratory by this method in three different materialssystems (Ag/Pd, Ag/Cu and Au/Ni) are reviewed. In case of Ag diffusion along Pd GBs the surfaceaccumulation was followed by AES method. The data points can be well fitted by an Arrheniusfunction with an activation energy Q=0.99eV.