Nucleation, growth and ageing scenarios in closed systems II: Dynamics of a new phase formation

Abstract

We simulate the dynamics of nucleation, growth and resorption of particles in an initially supersaturated closed medium, according to the approach worked out in the preceding paper, which applies to precipitation in solution, condensation in the vapor phase or crystallization from a melt. We find that the formation of the new phase obeys a generic scenario, involving mainly three stages, whatever the values of the parameters of the model: a phase of pure nucleation during which the supersaturation decreases, a plateau characterized by a quasi-equilibrium between nucleation and (positive) growth on the one hand, and resorption on the other hand, and an ageing stage ending with a single particle in thermodynamic equilibrium with its surrounding medium. During the plateau regime, very complex dynamical effects take place, which may be disentangled thanks to the full knowledge of the particle population obtained by our approach. We emphasize that the particles present in the system in the long time regime are not those formed at t = 0 , but rather during some (usually) short time interval(s) on the plateau. This point should be kept in mind when using crystal size distribution (CSD) to date events which have occurred in the past.