KINETICS OF FORMATION AND GROWTH OF A NEW PHASE WITH A DEFINITE STOICHIOMETRIC COMPOSITION

A kinetic description of the process of formation of a new phase with a well-defined ratio of the different components in a multi-component solid solution of arbitrary composition is developed. The process is d escribed in terms of cluster formation and growth in the conceptual fr amework of classical nucleation theory. Hereby the relation between th e rates of aggregation and dissolution of the aggregates of the evolvi ng phase is determined, however, by a different method as applied in t he classical theory avoiding the controversial introduction of so-call ed equilibrium distribution functions and the application of the princ iple of detailed balancing for clusters of supercritical sizes. Growth rates and steady state nucleation rates are derived for kinetic and d iffusion-limited growth modes as well as for the more general case, th at both transport processes as well as processes of aggregation of the primary units to the cluster determine the macroscopic growth rate.