Measurements of diffusion coefficients of60Co in the intermetallic compound CoGa

Diffusion coefficients of 60Co are measured in the intermetallic compound CoGa for five compositions containing 45.2 to 60.0 at% Co, in the temperature range from 800 to 1050 °C. The variation of the activation energy with composition shows a small but sharp decrease at an off-stoichiometric composition. A linear relation is found between the logarithm of the frequency factor and the activation energy. The frequency factor attains remarkably high values. The composition dependence of the diffusion coefficient exhibits an off-stoichiometric, temperature-dependent minimum. Strong indications are found for a curvature in the In D versus 1/T plots.