Magnetic Fe–Co and Its Oxide Nanopowders Produced by Chemical Vapor Condensation

Abstract

Fe–Co magnetic nanopowders were prepared by chemical vapor condensation (CVC) process, and some of their characteristics such as size, phase, oxidation behavior, and magnetic properties were investigated. Thermal behaviors of Fe–Co nanopowders were also studied by means of annealing in the air. Iron pentacarbonyl (Fe(CO)₅) and dicobalt octacarbonyl (Co₂(CO)₈) were used as precursors. XRD patterns showed that Fe–Co nanopowders were obtained in pure Ar, but that the Fe and Co oxide nanopowders were produced in the Ar + O₂ mixtures. Fe–Co nanopowders obtained in pure Ar consist of a core and a shell with a thickness of 2–4 nm. The saturation magnetization and coercivity decreased with increasing oxygen content in the carrier gases. The CVC nanopowders obtained in different carrier gases showed different Mössbauer spectrums.