Tracer diffusion measurements were performed, in vacuum and under high hydrostatic pressures, using amorphous samples. A marked structural relaxation effect was observed for both solutes, and led to a decrease in the diffusivity with annealing time. The relaxation time was nearly the same in both cases. For well-relaxed samples, the results could be described by:

Au:     D (m2/s) = 1.9 x 10-9 exp[-1.65(eV)/kT]

Hf:     D (m2/s) = 2.8 x 10-9 exp[-1.78(eV)/kT]

The activation volumes were equal to 0.51 and 0.52 atomic volumes, respectively.

A SIMS Investigation of Tracer Diffusivities in an Amorphous Ni54Zr46 Alloy. Y.Loirat, J.L.Bocquet, Y.Limoge: Journal of Non-Crystalline Solids, 2000, 265[3], 252-64