Tracer diffusion coefficients were measured for large- and small-sized impurities in several bulk metallic glass compositions. Molecular beam deposition was used to grow thin films, and secondary ion mass spectrometry was used to determine the concentration versus depth profiles of several tracers. A dependence of the atomic mobility of the tracer upon its size was found. The presence of Al reduced the diffusion coefficients in general, with a sharper decrease in the case of small-sized tracer. The results suggested the existence of 2 different diffusion mechanisms.

Diffusion in Amorphous NiZrAl Alloys. S.Flege, U.Fecher, H.Hahn: Journal of Non-Crystalline Solids, 2000, 270[1-3], 123-8