The tracer diffusivities of various impurity atoms in the metallic glass were measured, at 604 and 690K, by using secondary ion mass spectrometry. It was found that B atoms diffused some 2 orders of magnitude faster than Si atoms. The diffusivities of Be and Fe were intermediate, so that the overall trend in the coefficients was in the decreasing order: B – Be – Fe - Si. (table 91). This order was precisely opposite to the trend in the atomic radii of the diffusing species.

Size Dependence of Tracer-Impurity Diffusion in Amorphous Ti60Ni40. S.K.Sharma, M.P.Macht, V.Naundorf: Physical Review B, 1992, 46[5], 3147-50