Continuum modeling of size effects on the composition and stresses in nanoparticles of ionic solids with application to ceria. (March 2016)

• Record Type: Journal Article
• Authors: Haftbaradaran, Hamed; Mossaiby, Farshid
• Is Part Of: Journal of the mechanics and physics of solids. Volume 88(2016:Mar.)
• Page Start: 1
• Page End: 11
• Publication Date: 2016-03
• Subjects: Ionic solids -- Space charge models -- Nanoparticles -- Ceria -- Size effects; Mechanics, Applied -- Periodicals; Solids -- Periodicals; Mechanics -- Periodicals; Mécanique appliquée -- Périodiques; Solides -- Périodiques; Mechanics, Applied; Solids; Periodicals; 531.05
• DOI: 10.1016/j.jmps.2015.12.002
• Languages: English
• ISSNs: 0022-5096

Abstract

Abstract: Owing to its broad potential applications, nanostructured ceria has been subject of intense investigation in the past few decades. Experiments have demonstrated that various material properties of the nanostructured ionic solids including ceria vary with the feature size. Here, we present a theoretical study of the size effects on the composition, defect concentrations and stresses in free-standing nanoparticles of nonstoichiometric ionic solids. To this end, a continuum model is developed which accounts for the highly nonlinear coupling between mechanical, chemical and electrical driving forces, and their effects on the thermodynamic equilibrium of the defect species. It is demonstrated that the model, once applied to the case of ceria, predicts size-dependent defect concentrations and surface stresses. It is further shown that the theoretical predictions of the size effects on the composition and lattice parameter are in good agreement with the experimental observations. Highlights: A theoretical model is developed for studying nanoparticles of ionic solids. The model accounts for the chemical, electrical and mechanical driving forces. Size effects on the nonstoichiometric composition and lattice constant are discussed. It is shown that the compressive surface stress is smaller in smaller nanoparticles. Theoretical predictions are shown to be in good agreement with the experimental data.