Improvement of magnetic properties in lamellar Fe based soft magnetic composites by width-thickness ratio adjustment

Lamellar Fe based soft magnetic composites (SMCs) were fabricated using flaky iron powders obtained by ball milling. The magnetic properties of Fe based SMCs were optimized by regulating the width-thickness ratio of the iron powders, which was achieved by varying the ball milling time. During the ball milling process, the iron powder was subject to the squeezing and shearing forces exerted by the steel ball, thereby transforming into a lamellar morphology. The thickness of the lamellar iron powder gradually decreases with the ball milling time increases. And the width-to-thickness ratio of iron powder is significantly increased, which reduces the two-dimensional demagnetization factor of iron powder in magnetization direction and the effective eddy current diameter in the lamellar direction. Consequently, the magnetic permeability of iron powder core is significantly improved, and the eddy current loss is decreased, while the saturation magnetization exhibits slightly decline. When the ball milling time reaches 12 h, the lamellar Fe SMCs exhibit superior comprehensive performance, characterized by high saturation magnetization (215.48 emu/g), good magnetic permeability (78) and very low eddy current loss (0.745 kW/m3). © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.