Kinetics of two-phase layer growth during reactive diffusion

A quantitative model is proposed which describes the growth kinetics of a two-phase layer in a reactive diffusion experiment. The model is based on the concept of diffusion through the matrix phase being gradually blocked by the precipitates of a second phase with a low diffusivity of the components. The effect of precipitate morphology on the reaction zone growth is accounted for by introducing the dependence of diffusivity on the second phase fraction. Calculations according to this approach yielded a good match with experimental kinetics in the Ti–AlN system.