Interdiffusion in the β-NiAl homogeneity range was studied by using the diffusion couple technique at 1000 to 1200C. Intrinsic diffusivities at 1000C, for various compositions (figures 6 and 7), were measured by means of Kirkendall marker experiments. Variations of the molar volume, with composition and partial molar volume of the species, were calculated by using the lattice parameter and the vacancy concentration. Tracer diffusion coefficients of the species were calculated from the intrinsic diffusivities. The influence of the vacancy wind effect upon the calculated results was determined.

On Diffusion in the β-NiAl Phase. A.Paul, A.A.Kodentsov, F.J.J.van Loo: Journal of Alloys and Compounds, 2005, 403[1-2], 147-53

Figure 6

Activation Energy for Interdiffusion in β-NiAl