Papers by Author: A.S. Shirinyan

Abstract: The separation kinetics in a binary nanoparticle is studied by means of two-dimensional Monte-Carlo sampling and Ising-type model, where the species exchange positions due to vacancy mechanism. The model is developed in case of a free nanoparticle with a coating shell. The kinetics is shown to depend on the size of a nanosystem. We demonstrate a distinct size-induced freezing effect on kinetics of separation.

Abstract: The process of phase formation at the initial stage of the reaction diffusion and growth of a new phase particles - at the atomic level by applying the Monte-Carlo simulation of the crystalline nanoalloy is presented. The influence of initial composition on the kinetics of phase separation in a binary alloy with the fcc crystal lattice has been analyzed in detail. The dependences of various parameters of tire process - the average size of new-phase particles, volume of new-phase clusters, size distribution function, dispersion and supersaturation - on time have been calculated. The obtained results demonstrate the opportunity of a three-stage separation process at low initial supersaturation values and a two-stage separation at large initial supersaturation values.

Abstract: The influence of thermodynamic constraints like the size, depletion, surface tension and kinetic constraints like energy barrier for diffusion on nonsteady separation kinetics in binary nanopowder is investigated. Here we present a numeric analysis of size hysteresis and its peculiarities using the standard kinetic equation approach.