Synthesis and characterization of iron oxide nanoparticles prepared by electrical explosion of fe wire in Ar-O 2 gas mixtures

Abstract

Iron oxide nanoparticles were prepared using a wire explosion method. Pure Fe wire was exploded in Ar-5%O 2, Ar-10%O 2 and Ar-30%O 2 gas mixtures. The variation in the oxygen partial pressure in the explosion chamber resulted in a full spectrum of iron oxide nanoparticles, the sizes of which ranged from 10 to 200 nm. The phases in the explosion products were augmented in the order FeO → magnetite (Fe 3O 4) → maghemite (γ-Fe 2O 3) → hematite (α-Fe 2O 3) as the oxygen partial pressure was increased. Among the oxide phases, magnetite (Fe 3O 4) and maghemite (γ-Fe 2O 3) were the major phases, and the identification and relative quantification of both phases was possible through a step-scan and peak deconvolution routine. The presence of the magnetite-maghemite phase mixture was also substantiated by a field-emission transmission electron microscopy (FE-TEM) study on individual particles. The average particle size and phase ratio (maghemite/magnetite) decreased with increasing oxygen partial pressure. © 2012 The Japan Institute of Metals.