Preparation of FeSiBC soft magnetic composites with excellent magnetic properties and environmental reliability based on mechanofusion method

It remains a challenging task to improve the environmental stability of soft magnetic composites (SMCs) due to conventional wet-coating methods. To address these problems, this study employs a mechanofusion (MF) method to construct a uniform, dense, and stable inorganic glass (GP) insulating layer on the surface of amorphous powders. The microstructure, composition, and soft magnetic properties of FeSiBC/GP composites were thoroughly characterized, elucidating the relationship between magnetic performance and the glass insulating layer. A three-dimensional loss separation model was applied to theoretically analyze the variation mechanism of power losses in SMCs, revealing that excessively thick insulating layer exert adverse effects by increasing hysteresis and residual losses. Notably, when the glass powder content reached 1.0 wt%, the insulating layer on the amorphous powder surface measured approximately 100 nm in thickness, resulting in optimal magnetic properties. Specifically, the SMCs exhibited power loss ( P cv ) of 159.43 mW/cm 3 (100 kHz, 50 mT), effective permeability ( μ e ) of 71.11 (∼1000 kHz), and DC bias performance of 61.75 % (100 Oe). Moreover, the environmental reliability of SMCs prepared via MF method was significantly superior to that of traditional wet coating methods. Consequently, SMCs fabricated using this innovative method demonstrate excellent soft magnetic performance and environmental reliability, making them highly promising for high-frequency electronic applications.