VACANCY MECHANISM OF MELTING AND SURFACE ROUGHENING OF METAL NANOPARTICLES

Abstract

Within the limits of the uniform approach with the assistance of the vacancy mechanism the description of melting and surface roughening of both free nanoparticles and nanoparticles deposited on the surface of solid body under conditions of thermodynamic equilibrium is offered. Surface roughening of a spherical particle is represented as a phase transition in vacancy subsystem, in which supersaturation is formed by reducing the particle size. It is shown that interaction between vacancies result in to the unification of vacancies on a surface in vacancy clusters, that can be regarded as the appearance of a surface roughness of nanoparticles. It is shown that increasing concentration of vacancies caused by the modification of effective vacancy formation energy with decreasing sizes of nanoparticles result into a modification of shear modulus of material. By vanishing the shear modulus (Born criteria of melting) the dependence of temperature of fusion of nanoparticles of different metals on radius was determined.