Low core loss and high DC bias performance of FeSiAl soft magnetic composites cores with hybrid insulating layers of MgO/SiO2

Soft magnetic composites (SMCs) play an indispensable role in electromagnetic conversion, transmission, and storage. However, in order to achieve miniaturization, energy conservation, and meet the application requirements of premagnetisation in direct-current (DC) components, SMCs are required to have low core loss and high DC bias performance. In this work, FeSiAl SMCs with hybrid insulating layers of MgO/SiO2 have been successfully prepared by the decomposition of magnesium acetate tetrahydrate and silicone resin. The presence of MgO and SiO2 insulating layers can effectively compensate for each other's coating defects, thereby forming complete insulating layers on the surface of FeSiAl powders to reduce the core loss. Finally, the FeSiAl@MgO/SiO2 SMC gets remarkable comprehensive magnetic properties with a low core loss (Pcv) of 163.7 mW/cm3 at 50 mT/100 kHz, a high DC bias performance of 53.7% at 100 Oe, and an effective permeability (μe) of 46, which is promising for high-frequency and high-power applications.