Construction of kinetic phase diagrams

It is a noted fact that the composition of a mixed solid phase grown at non -equilibrium can deviate from the equilibrium composition due to the very l ow diffusion rate in the solid phase. We present an analytical model for th e determination of the kinetic composition of a binary solid phase that is growing from a solution at a given supersaturation, giving rise to kinetic phase diagrams. The model is derived for growth at rough surfaces but is ex pected to apply also to growth at non-roughened surfaces. Kinetic phase dia grams for different undercooling and excess energy parameters are presented and discussed. If the interaction parameters, describing the excess free e nergy, are large the model equations can have two stable solutions, which i mplies the simultaneous growth of two solid phases with different compositi ons. This kinetic phase separation depends on the undercooling and the comp osition dependence of the attachment probabilities.