Identification of complex core-shell nanostructures from the radial distributions of the local density of components

Abstract

The paper is devoted to the substantiation and further development of the approach to the analysis of the mesoscopic and integral structure of binary metal nanoparticles from the radial distributions of the local density of the components. As an example, the local density distributions of Ni and Al obtained using the results of molecular dynamics modeling of binary Ni-Al nanoparticles with an initial uniform distribution of components and Ni@Al core-shell icosahedral nanostructures are considered. Both patterns demonstrate the surface segregation of Al atoms during relaxation and subsequent quenching of the initial configurations containing 5000 atoms in 1:1 ratio (nanoparticle radius 3 nm). During cooling, the temperature of the nanoparticles decreased from 1000 K to 0,01 K with a low for atomistic simulation cooling rate. Experimentally binary Ni-Al nanoparticles with a radius of about 100 nm (76Ni:24Al at.%) were synthesized by the wire electric explosion. The experimental intensity distributions obtained from the data of energy-dispersive analysis under the action of an electron beam are presented and analyzed. These distributions correspond to a greater extent to the initial configurations in our molecular dynamics experiments, i.e., they are obviously nonequilibrium. At the same time, it was concluded that the final molecular dynamic configurations are also not entirely equilibrium.

Keywords

• core-shell nanostructures
• ni-al nanoparticles
• radial density distributions
• embedded atom method
• tight binding potential
• molecular dynamics
• wire electric explosion method
• energy- dispersive analysis