ON THE PROBLEM OF THE PHASE DIAGRAMM FOR BINARY METAL NANOPARTICLES

Abstract

The problem of the phase diagram for binary metal nanoparticles is stated and discussed. From this viewpoint, three size ranges of metal nanoparticles are distinguished: small metal nanoparticles less than 1-2 nm in size, for which concepts of the thermodynamic phase and phase transitions seem to fail completely, mesoscopic particles containing from several hundreds to several thousands of atoms and big particles of order of 100 nm in size, for which the size dependence of the surface energy is not principal. As a pattern of phase diagrams for mesoscopic particles, phase diagram for binary Au-Ag particles consisting of 2000 atoms has been obtained using molecular dynamics results and discussed. It has been found that the form of this phase diagram principally differs from that for the corresponding balk phases. The melting-crystallization hysteresis is treated as the main reason of such a divergence.

Keywords

• phase diagram
• binary nanoparticles Au Ag 
• melting-crystallization hysteresis