Phase transformations in nanoparticles produced by electrospark treatment of metallic granules

Abstract

The results of the study of phase transformations in nanoparticles produced by electric electrospark treatment of copper and iron granules in water and organic liquids are shown. The laws of change equilibrium temperatures of phase transformations in nanoparticles depending of the shape, surface finish and ratio of the free energies of the initial and the formed nanoparticles was defined. The phase diagrams of binary alloys I, II, III and IV of the types in the nanoscale and bulk state are shown. Experimentally determined parameters termokinetics phase transformations during heating nanoparticles containing copper (CuO → Cu₂O) and iron (α-Fe → FeO, Fe₃O₄ → FeO, γ-Fe → α-Fe, α-Fe → Fe₃O₄, Fe₃O₄ → Fe, α-Fe → γ-Fe, dissolution C in γ-Fe, melting austenite), and the at cooling of the bulk material, obtained after melting of the iron nanoparticles (austenite solidification, carbon precipitation from of the austenite and γ-Fe → α-Fe transformation). Heat transformations γ-Fe → α-Fe, α-Fe → γ-Fe, dissolution C in γ-Fe, austenite melting during heating nanoparticles and austenite solidification, also γ-Fe → α-Fe transformations during cooling of the bulk material, obtained after melting of the iron nanoparticles were determined. Full text download