Shrinking kinetics by vacancy diffusion of hollow binary alloy nanospheres driven by the Gibbs-Thomson effect

• Published in: Philosophical magazine (Abingdon, England) England), 2008-04, Vol.88 (10), p.1525-1541
• Main Authors: Evteev, A.V., Levchenko, E.V., Belova, I.V., Murch, G.E.
• Format: Article
• Language: English
• Subjects: binary alloy; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; diffusion; Diffusion in solids; Diffusion of impurities; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; hollow nanospheres; Materials science; Monte Carlo; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Physics; Solubility, segregation, and mixing; phase separation; stability; Transport properties of condensed matter (nonelectronic); vacancies
• ISSN: 1478-6435; 1478-6443
• DOI: 10.1080/14786430802213413

The general treatment of the Gibbs-Thomson effect for a hollow nanosphere is presented. It allows for a vacancy composition profile across the nanoshell to be defined by a continuously decreasing function as well as by a continuous function with a minimum. The range for the controlling parameter of the vacancy motion within a binary alloy nanoshell is determined in terms of the phenomenological coefficients as well as the (measurable) tracer diffusion coefficients ( ) of the atomic components. On the basis of a theoretical description and kinetic Monte Carlo simulations, it is demonstrated that for a hollow random binary alloy nanosphere with an equi-atomic (initially homogeneous) composition and neglecting the radial dependence of vacancy formation free energy, the controlling parameter of the shrinking rate in the limiting case can be estimated with reasonable accuracy as the geometric mean of the tracer diffusion coefficients of the atomic components.