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.