The topologically close-packed Fe70Cu15Ni15 nanoparticles : a simulation study

The classical molecular dynamics simulation is performed to investigate the frozen structure obtained by rapid cooling Fe70Cu15Ni15 nanodroplets, in terms of the system energy, the pair distribution function (PDF), and the largest standard cluster analysis (LaSCA). Interestingly, all frozen nanodroplets have a core-shell structure with copper atoms on the surface, whether they are amorphous or crystalline nanoparticles. Besides the familiar body-centered cubic (BCC) structure, a topologically close-packed (TCP) nanoparticle is observed for the first time. For a type of nanodroplets, the larger the size, the higher the onset temperature of crystallization, and the lower the potential energy of the nanoparticles at 300 K. For BCC nanoparticles crystallinity increases with size, but this is not the case for TCP nanoparticles. These findings indicate a simple and efficient way to produce core-shell nanoparticles.