Phase separation in nanoparticles

The influences of the size, thermodynamic quantities and depletion of the parent phase on the separation thermodynamics of nanosized supersaturated binary solid solutions are studied theoretically. A quantitative analysis of the nucleation of one nucleus and of the decomposition in small isolated nanoparticles is presented. It is shown that three possibilities exist: phase separation, prohibition of decomposition, and formation of the metastable state of the nanoalloy. The conservation of matter leads to constraints on nucleation and growth of new phases. The case of solid–solid transition phenomena in a nanosystem is studied for regular solutions. This model leads to the existence of multiple equilibrium configurations for the same sets of initial parameters. Phase diagrams of small particles, i.e. probability-size, nucleation barrier-solubility, temperature-composition, are plotted within a regular solution model.