Preparation of Soft Magnetic Composites with a Bionic Shell Structure via a Multilayer Casting Sheet

Soft magnetic composites (SMC) with a bionic shell structure and a delicate, regular layered arrangement were prepared via a casting process. The permeability of composite samples was 140 at 5 MHz for plane anisotropy, while that of the spherical-particle-constructed material is only 14. According to classical loss separation results, the layered bulk material without an SiO2 coating exhibited lower hysteresis loss. In contrast, the layered bulk material coated with SiO2 showed lower eddy current loss, attributed to the increase in resistivity resulting from the SiO2 coating. The magnetic loss of the layered bulk materials was 588 kW/m3 at 50 mT and 100 kHz. SMC materials with this structure are anticipated to have strong potential for magnetic cores used in high-efficiency power supplies.