Impact growth structures of nanoalloys: Atomistic simulation on an immiscible Cu-Ag system

Abstract

authoren The impact deposition of Ag (or Cu) atoms over Cu (or Ag) nanoparticle with truncated octahedral structure is studied by molecular dynamics. The embedded‐atom method is used to describe interatomic interactions. The simulations are performed at incident energies of 10 to 50 eV. The incident‐energy dependence of the deposition on configurations of Cu–Ag nanoparticles is analyzed. For the deposition of Ag atoms on Cu substrate, a perfect Cu‐core/Ag‐shell nanoparticle with truncated octahedral structure is obtained at all considered incident energies. A reversed core–shell nanoparticle with Cu covering the surface is observed at lower incident energies as Cu atoms are deposited on Ag substrate. An icosahedral multi‐core nanoparticle with Ag bridging several Cu cores is also observed with increased incident energy to 50 eV. These simulation results well agree with the experimental observations. The transformation from truncated octahedron to icosahedron is attributed to the incident energy and immiscibility of Cu–Ag.

Extended Dislocations in Plastically Deformed Metallic Nanoparticles

“…However, the prediction of the properties at other temperature is reliable, for example solubility energies (1052 K) and the enthalpy of mixing of liquid Cu-Ag solutions at 1423 K. Further, a simple Cu-Ag phase diagram can be predicted by current embedded-atom method (EAM) potential, which is comparable to experimental results. Many researchers have employed current potential to study the formation and properties of Cu-Ag nanostructures using an MD simulation method [18][19][20][21][22][23][24][25]. The success of investigations into the mechanical deformations of the Cu-Ag system particularly encourages this work.…”

Mass Transport in Nanoalloys Studied by Atomistic Models

“…The effects of nanoscale atomic mobility are even better appreciated by monitoring the evolution of nanoparticle and nanoalloy growth by MD simulations. There are several examples of such simulations in the literature [63,16,17,5,33,34,35,37,38,39,49,1]. Here we focus on the deposition of Cu atoms on preformed Ag clusters, which is often referred to as inverse deposition [5], since deposited atoms have the tendency to incorporate inside the preformed seed due to the smaller size and higher surface energy of Cu with respect to Ag.…”

“…Simulation studies of the evolution of nanoalloys are more numerous, mostly by Molecular Dy namics (MD) [25,4,5,33,34,35,36,37,38,39,40,40,41,42,43] or Monte Carlo (MC) methods [44,45]. In the following we show how MD simulations can be a very effective tool for studying diffusion in nanoparticles.…”

Structural and Thermodynamic Behaviors of CumAgn (m + n = 144–147) Nanoalloys during Cooling: Implications for Nanoparticle Structure Control

“…10−15 The binary combinations become more miscible at the nanoscale than their bulk counterparts and form a variety of configurations. 16,17 Due to the low surface energy and large atomic size of Ag as well as the existence of a miscibility gap in the Cu−Ag bulk, Cu−Ag nanoalloys are stable in the core−shell structure under certain conditions. 18,19 There is a significant lattice mismatch between the smaller atom Cu and the larger atom Ag, which leads to different stress in the core and shell of Cu@Ag nanoalloys.…”

“…One of the most important issues of the nanoalloys is to characterize their structures as well as their properties in producing the particles with well-defined sizes and shapes. Owing to the surface, size, and composition effects, the alloying nanoparticles present multi-structures, including core–shell, sub-cluster segregation, and three onion-like, mixed, and Janus configurations. − As a typical eutectic alloy of bulk Cu–Ag phase, Cu–Ag nanoalloys can be widely applied as catalysts, sensors, electrodes, lead-free nano-solders, and so forth. − The binary combinations become more miscible at the nanoscale than their bulk counterparts and form a variety of configurations. , Due to the low surface energy and large atomic size of Ag as well as the existence of a miscibility gap in the Cu–Ag bulk, Cu–Ag nanoalloys are stable in the core–shell structure under certain conditions. , There is a significant lattice mismatch between the smaller atom Cu and the larger atom Ag, which leads to different stress in the core and shell of Cu@Ag nanoalloys. When the core is small, its atoms are subjected to positive compressive stresses, and therefore the central position of the core is stable.…”