Ultra-low core loss and high permeability Fe-based amorphous soft magnetic composites with ultra-fine FeNi additives

The rapid development of wide bandgap semiconductor technology has set a higher standard for the permeability, core loss, and DC-bias performance of soft magnetic materials. In order to prepare soft magnetic materials with excellent high-frequency properties, novel Fe-based amorphous soft magnetic composites (SMCs) composed of FeSiBCCr amorphous powder and ultra-fine FeNi powder were developed by cold pressing. The effects of the mass ratio of FeNi powder on the micromorphology, densities, and magnetic properties of FeSiBCCr amorphous SMCs were thoroughly investigated. The results show that the ultra-fine FeNi powder is incorporated into the voids between the FeSiBCCr amorphous powder, which can effectively reduce the air gaps, resulting in excellent magnetic properties even at high frequency and temperature. The comprehensive soft magnetic properties of FeSiBCCr/FeNi SMCs have been significantly improved compared to those of individual FeSiBCCr SMCs. The composite SMCs, with the addition of 50 wt% FeNi powder and annealed at 450 °C, exhibit excellent magnetic properties with high effective permeability of 44.6, ultra-low core loss of 640 kW/m³ at 50 mT and 500 kHz, and high DC-bias performance of 93.8%. The demonstrated FeSiBCCr/FeNi SMCs with high performance are expected to be widely used in high-power and high-frequency electronics applications.