Fabrication of spherical Fe-based magnetic powders via the in situ de-wetting of the liquid–solid interface

Abstract

Spherical Fe-based magnetic powders were obtained by taking advantage of the surface tension of a molten metal and the de-wetting of metal droplets on a solid graphite sea. The surface carbides inhibit the interfacial reaction and suppress the wetting of the alloy in the graphite substrate. Cross-sectional micrographs of the spherical particles indicate that the particles are fully dense without pores and bulk inclusions. The amorphous degree of the spherical powder was improved by directly quenching in water compared to the raw materials, and the directly quenched sample exhibits excellent soft magnetic properties. Our strategy is expected to provide a new route for the fabrication of spherical insulation coated Fe-based magnetic powders for use in high frequency devices as magnetic core powders.