Interdiffusion in the amorphous layers of Ni66.59P34.41/Ni38P62 sandwich structures was studied, at temperatures ranging from 470 to 550K, by using Auger electron depth profiling techniques. The Boltzmann-Matano method was used to obtain diffusion coefficients from the depth profile data. A marked compositional dependence of the diffusion coefficient was explained in terms of the concentration dependence of the free energy for an amorphous alloy, and the role of free volume in interdiffusion at the interface of the 2 layers. At a composition of 50at%P, the data could be described by:

D (cm2/s) = 1.20 x 10-10exp[-0.72(eV)/kT]

A.Bukaluk: Czechoslovak Journal of Physics, 1993, 43[9-10], 887-91