Tracer diffusion in this amorphous alloy was measured at temperatures ranging from 598 to 690K (tables 303 and 304) by using secondary ion mass spectrometry for depth profiling. It was found that the temperature dependences of the diffusion coefficients obeyed an Arrhenius behavior and yielded activation energies of 2.05, 2.20, 2.33 and 2.35eV for the diffusion of B, Be, Fe and Si, respectively. The corresponding values of the pre-exponential factors were 7.4 x 10-4, 1.7 x 10-3, 2.5 x 10-3 and 5.8 x 10-4m2/s. The results revealed a size dependence of the diffusivity, in that the small B atoms diffused some 2 orders of magnitude faster than did the large Si atoms. The diffusivities of Be and Fe took intermediate values according to the trend: DB > DBe > DFe > DSi. This was opposite to that of the atomic radii of the species: rSi > rFe > rBe > rB.

S.K.Sharma, M.P.Macht, V.Naundorf: Physical Review B, 1994, 49[10], 6655-66

Table 300

Diffusivity of 59Fe in Ti