The vacancy-wind factor (for chemical diffusion) appearing in the Darken-Manning equation was calculated by computer simulation using migration energies determined previously by Schmidt and Bocquet. These migration energies had previously been shown to be consistent with the tracer diffusion behaviour in Ni3Al. It was shown that the vacancy-wind factor could differ considerably from that calculated using Manning's well-known expression. In particular, the vacancy-wind factor was no longer bounded above by the reciprocal of the geometrical tracer correlation factor.

Chemical Diffusion in Ni3Al. Murch, G.E., Belova, V.: Defect and Diffusion Forum, 2001, 194-199[1], 541-6

Table 1

Chemical diffusion coefficient in Ni3Al