Influence of dispersity on local physical, structural, magnetic and thermodynamic properties of bcc Fe and its binary alloys

Abstract

Abstract The model was proposed for iron nano-particles (and solid solutions based on bcc-Fe) containing a core and a surface layer coherent with each other in the form of a two-phase stratifying parts (“surface” and bulk) system with different local physical properties. Using the results of measurements of the experimental temperature dependence of the heat capacity and the application of the Debye models for both the “core”-phase and the surface layer (“surface”-phase) as two-phase heat capacity components for Fe nanoparticles, it was shown by calculations that the local elastic modulus for the surface layer is nano-particles are approximately 2 times smaller than for the “core”-phase of the nano-particle iron. The purpose of the research is to establish the relationship between local physical properties (bulk modulus of elasticity, static displacements of iron atoms surrounding an impurity atom, magnetic moments) for the core part and the surface layer of nanoparticles. From the condition of local mechanical equilibrium it was shown that static displacements of Fe atoms around an impurity atom in various coordination spheres on the surface of nanoparticles of Fe-rich binary BCC solutions of Fe - (Cr, V, Mo, W) with nano-particles increase significantly (compared to static displacements of Fe atoms “core” of nano-particles).