Intrinsic diffusion in Ni₃Al

Intrinsic diffusion coefficients of Al and Ni in Ni₃Al are determined using Ni/NiAl couples. The composition of the NiAl is controlled so that the Kirkendall interface is present in the Ni₃Al phase formed in the couple. Concentration profiles are measured across the interface and interdiffusion coefficients of Ni₃Al are determined from the profiles using the Sauer-Freise technique. The Darken's equation is applied for the determination of the intrinsic diffusion coefficients. It is shown that the intrinsic diffusion coefficients of Al and Ni in Ni₃Al are in almost the same magnitude. The self-diffusion coefficients of Al and Ni in Ni₃Al are also estimated using the Manning equation. The present results are consistent with the diffusion mechanisms considering anti-site defects.