Size- and temperature-dependent coalescence behavior of Ag-Co nanoparticles: a molecular dynamics study

Abstract The coalescence process of Ag-Co nanoparticles was investigated by molecular dynamics simulations. In the first case, the coalescence between two truncated octahedral (TO) seeds composed of 140 Ag and 140 Co atoms and two icosahedral (Ih) seeds composed of 147 Ag and 147 Co atoms was analyzed. In the second case, it was analyzed for two much larger seeds with 309-atom Ih and 314-atom TO. Five different coalescence temperatures were considered, in the range 400–600 K for each size. Common neighbor analysis (CNA) and radius of gyration analysis were carried out for the structural and chemical ordering changes for all systems. Molecular dynamics results show that the resultant structures of larger sizes are not very compact and more elongated than in the case of small-sized configurations. Also, the radius of gyration analysis shows that Ag atoms exhibit a larger radius of gyration compared to Co atoms for all sizes, indicating the tendency of Ag atoms of covering the Co atoms, which have higher surface and cohesive energy.