Melting Mechanisms of Coated Nanoparticles

Nanoparticles melt at lower temperatures as their dimension becomes smaller. With a coating layer of higher melting temperature, the nanoparticles become more resistant to melting. Using classical molecular dynamics simulations, the authors show the competition of two melting mechanisms of coated nanoparticles. Copper is the prototype of nanoparticle materials, and the coating materials have higher melting temperature but same crystal structure. Further, the authors develop an analytical formulation of critical conditions that separate the two melting mechanisms, and verify the formulation using molecular dynamics simulations. This critical condition can help guide the selection of coating materials for nanoparticles in high temperature applications.