On the problem of stability/instability in core-shell ternary Cu-Fe-Ni nanoparticles

Abstract

The article is devoted to the study of stability of ternary Cu-Fe-Ni nanoparticles (consisting of 5400 atoms) with a core-shell structure and its relationship with the surface segregation. The main focus is on modeling their structural formation using the LAMMPS software. The authors test the hypothesis that stability of nanoparticles depends on the spontaneous segregation of one of the components to the surface. Three configurations with different atomic distributions (configuration Cu45Fe45Ni10 with random distribution of atoms, as well as configurations – Cu25Fe25@Ni50 and Fe25Ni25@Cu50) are considered, and numerical modeling is performed for each of them using molecular dynamics methods and applying the tight-binding and embedded atom method potentials. The analysis showed that copper tends to segregate to the surface, while nickel concentrates in the core, significantly affecting mechanical properties of the nanoparticles. Patterns of the defect formation and their impact on the strength of nanostructures were identified. The article emphasizes that the correct choice of shell and core can both stabilize and destabilize the nanoparticles, providing prospects for the practical application of these materials.

Keywords

• molecular dynamics method
• lammps
• embedded atom model
• tight-binding potential
• polyhedral template matching method
• ternary nanoparticles
• nickel
• copper
• iron
• structural formation
• caloric curve