Structure and magnetic properties of FeSi/Co₃O₄ inductor core used for smart meters

FeSi based inductor core with a Co₃O₄ coating was prepared by ball milling combined with subsequent molding and annealing. Effects of the Co₃O₄ content on microstructure and magnetic properties of the FeSi/Co₃O₄ inductor core were systematically studied. The results showed that Co₃O₄ nanoparticles were uniformly coating on the surfaces of FeSi magnetic powders by ball milling process. When the Co₃O₄ content increased from 0.0 to 10 wt%, the Co₃O₄ coating was thickened and gradually completely covered the surfaces of the FeSi magnetic powders. Consequently, the saturation magnetization and permeability were decreased due to the non-magnetism of the Co₃O₄ coating. Meanwhile, the increase of the Co₃O₄ content was beneficial for reducing eddy current loss and total core loss, and improving frequency stability of permeability, indicating good high-frequency inductance characteristic for the FeSi/Co₃O₄ inductor core with relatively high Co₃O₄ content. Thus, the FeSi/Co₃O₄ inductor core proposed in this work has potential application prospects in the field of inductor components.