In the present paper, preparation of nanocomposite powders of mutually immiscible Fe and Cu metals with different Fe-to-Cu ratios by electric explosion of wires and their processing into bulk materials are reported. Near-fully dense nanocrystalline Fe-Cu specimens with high compressive and bending strengths are obtained by high pressure consolidation/cold sintering of the electrically exploded powders at 3 GPa. Reduction treatment in an H 2 -flow prior to consolidation results in an intimate contact between the oxide free powder surfaces and in an excellent inter-particle bonding integrity. The Cu-rich composition exhibits an attractive combination of high strength and relatively low electrical resistivity.
Magnetic nanoparticles based on iron and its oxides are promising in various biomedical applications. Currently, as a rule, ferromagnetic iron oxide particles with a low specific magnetic moment are used for medical purposes. In the present work, a new method for the synthesis of magnetic nanoparticles based on the electric explosion of a Fe wire is proposed. When wires are dispersed by high current electric pulse in an inert atmosphere containing less than 5% oxygen, nanoparticles with a core-shell structure are formed, where the core is α-Fe and the shell is formed by a mixture of oxides Fe 3 O 4 and FeO. The oxygen concentration in the buffer gas has been found to determine the size of the resulting nanoparticles, their shape, and iron content. The iron oxide shell protects the iron core from the external environment, preventing the rapid dissolution of Fe containing in the nanoparticles, in contrast to nanoparticles obtained in argon atmosphere. The specific magnetic moment of nanoparticles, depending on the content of iron oxides, varies from 90 to 180 emu/g. Keywords Fe-Fe 3 O 4 nanoparticles . Electrical explosion of a wire . Oxidation . Core-shell structures . Magnetic properties
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