The tracer diffusivity of 110Ag was measured, at temperatures ranging from 800 to 950C, by means of serial sectioning. Polycrystalline samples were prepared from conventionally produced powder which contained about 0.2%Zr, or from purer powder which had been calcined in low-pressure O. The concentration profiles indicated the existence of both bulk and fast diffusion-path contributions to diffusion. It was found that the diffusion activation energies were equal to 227 and 249kJ/mol for samples which had been prepared from pure and normal powder, respectively. Diffusion was slower in samples which had been prepared from purer material.

N.Chen, S.J.Rothman, J.L.Routbort: Journal of Applied Physics, 1990, 68[5], 2523-5