Diffusion of inert gases in silver—II. Recrystallized and single crystalline silver

Abstract

The diffusion of Kr and Xe in pre-annealed, recrystallized silver foils and in silver single crystals was studied employing the technique of ion bombardment to label the solid with gas. Gas diffusion was followed by both release measurements and measurements of the concentration profiles of the gas remaining in the solid following annealing. At low bombardment doses, most of the gas release was compatible with a volume diffusion process with an activation enthalpy, ΔH, of 1.75 eV, a value which is slightly smaller than that of silver self-diffusion, but somewhat bigger than predicted by theory. A small fraction of the gas seemed to be trapped even at low gas concentrations (3 × 10 −5 at. %). The ΔH was independent of bombardment energy (5–450 keV) and hence of changes in the diffusion distance by about a factor of 10 2, as would be expected for a volume diffusion process. At higher doses, release was retarded and the apparent ΔH-values surpassed that of silver self-diffusion. This was explained as being due to interactions of gas atoms with radiation damage. The results are compared with those obtained on cold-worked silver and are used to explain the unusually big scatter in the published literature.