Interdiffusion rates in solid face-centered cubic Fe–Ni alloys were measured at pressures between 1 and 23GPa at 1423 to 1973K. The experiments were performed using piston cylinder and multi-anvil devices, with diffusion couples comprising pure Fe and Ni rods placed end to end. Concentration profiles in quenched samples were measured by electron microprobe, and interdiffusion coefficients were determined using the Boltzmann–Matano method. Over the entire range of pressure and temperature studied, the interdiffusion coefficients in the Fe-rich alloys were described well by:

D (m2/s) = 2.7 x 10-4 exp[-20.4Tm/T]

where Tm was the melting point of the alloy at the pressure of interest. These data were consistent, to within an order of magnitude, with data for other close-packed metals at the same homologous temperatures.

Interdiffusion of Solid Iron and Nickel at High Pressure. M.L.Yunker, J.A.Van Orman: Earth and Planetary Science Letters, 2007, 254[1-2], 203-13