Enhanced magnetic properties of anisotropic Nd-Fe-B nanocomposites by Fe(C) coating

Abstract Nanostructured anisotropic Nd-Fe-B/Fe(C) composite powders were prepared by coating Fe(C) soft-magnetic nanoparticles on HDDR Nd-Fe-B hard magnetic powders using iron pentacarbonyl Fe(CO)5 as soft-phase precursor. The effect of Fe(CO)5-loading amount on soft-phase purity, coating morphology and magnetic properties of the composite powders was investigated. Dense and continuous Fe(C) soft-phase coatings with average particle sizes of 59–68 nm are obtained at Fe(CO)5 loading amount of x≤12 wt%, leadingto enhanced remanence and improved energy product of the coated powders. Positive value in δM-plots and single-phase-like demagnetization curves are observed in Nd-Fe-B/Fe(C) composite powders, indicating exchange coupling effect between the coated Fe(C) soft phase and the Nd-Fe-B hard phase.