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.