Size effect on alloying ability and phase stability of immiscible bimetallic nanoparticles |
| |
Authors: | S Xiao W Hu W Luo Y Wu X Li H Deng |
| |
Institution: | (1) Department of Applied Physics, Hunan University, 410082, Changsha, P.R. China |
| |
Abstract: | In the present paper, the surface and size effects on the
alloying ability and phase stability of immiscible alloy
nanoparticles have been studied with calculating the heats of
formation of Au-Pt alloy nanoparticles from the single element
nanoparticles of their constituents (Au and Pt) with a simple
thermodynamic model and an analytic embedded atom method. The
results indicated that, besides the similar compositional dependence
of heat of formation as in bulk alloys, the heat of formation of
alloy nanoparticles exhibits notable size-dependence, and there
exists a competition between size effect and compositional effect on
the heat of formation of immiscible system. Contrary to the positive
heat of formation for bulk-immiscible alloys, a negative heat of
formation may be obtained for the alloy nanoparticles with a small
size or dilute solute component, which implies a promotion of the
alloying ability and phase stability of immiscible system on a
nanoscale. The surface segregation results in an extension of the
size range of particles with a negative heat of formation. The
molecular dynamics simulations have indicated that the structurally
and compositionally homogeneous AuPt nanoparticles tend to form a
core-shell structure with temperature increasing. |
| |
Keywords: | 61 46 -w Nanoscale materials 64 75 +g Solubility segregation and mixing phase separation |
本文献已被 SpringerLink 等数据库收录! |
|