Magnetic Properties of High DC Bias Performance Fe-Si-B-C-Cr Amorphous Soft Magnetic Composites

The present study investigates three types of Fe-Si-B-C-Cr non-crystalline magnetic powder and their effects on the magnetic properties of soft magnetic composites. Specifically, the study examines the impact of heat treatment temperature and particle size distribution. The results indicate a positive correlation between the size of the magnetic powder particles and saturation magnetization. Changes in heat treatment temperature similarly affected the magnetic properties of the three soft magnetic composites, with the optimal temperature for heat treatment determined to be 460 °C. Nonlinear fitting was used to separate the total loss, and it was found that non-crystalline soft magnetic composites made with small-sized magnetic powder exhibited lower eddy current loss under MHz magnetic field conditions. The relaxation phenomenon observed in the hysteresis loop with increasing frequency under a dynamic magnetic field explains the mechanism of power loss variation in soft magnetic composite materials with respect to magnetic field frequency and magnetic induction intensity. A high-performance non-crystalline soft magnetic composite with a power consumption of 372 kW/m3 was obtained at a magnetic induction intensity of 20 mT and a frequency of 1 MHz. Which demonstrated excellent stability under MHz magnetic field conditions as well as excellent DC bias characteristics, with a relative permeability above 90% under a DC bias magnetic field of 7.96 kA/m.