Size effect in four-component Au-Cu-Pd-Pt nanoparticles and their stability

The four-component Au-Cu-Pd-Pt nanosystems of different sizes with the stoichiometric composition Au3CuPd12Pt4 were studied. The molecular dynamics method was used as a simulation method, the interatomic interaction was described by the tight-binding potential. Based on the results of a series of computer experiments, it was found that the four-component Au-Cu-Pd-Pt nanoparticles do not have a tendency to form a core-shell structure, even though gold atoms demonstrate an increased segregation to the surface. Melting and crystallization temperatures were determined for the studied Au-Cu-Pd-Pt nanoparticles. The dependence of the crystallization temperature on the cooling rate was also established. With an increase in the cooling rate, the crystallization temperature decreases, and the temperature range in which crystallization occurs increases, while the heating rate does not significantly affect the melting temperature. It is shown that the size effect and the effect of the temperature-changing rate make it possible to control the dominant presence of the fcc or hcp local structure, and also affect the temperature stability of the resulting crystalline phases.