Diffusion in the intermetallic compound CoGa

In this paper a model for diffusion by isolated vacancies is postulated for stoichiometric CoGa. The model is one in which the sublattices exist a priori and the distribution of atoms in each sublattice is random. Four atom-vacancy exchange frequencies and vacancy concentrations up to 6% were specified, as exhibited by stoichiometric CoGa. Monte Carlo computer simulation was used to determine the ratio of the diffusion coefficients. It was shown that the triple-defect mechanism which has been postulated to explain the high value of the measured ratio of the diffusion coefficients is actually unnecessary to invoke. The ratio can be explained readily by the present model of diffusion by isolated vacancies.