Designing Advanced Soft Magnetic Powder Cores with Ultralow Energy Loss by Combining Ultrasonic and Static Compaction

Power inductors are critical in electronics and automotive systems, with integrated inductors gaining attention for miniaturization and high power efficiency. Iron-based amorphous/nanocrystalline soft magnetic powders offer high permeability and low core loss, yet their high strength and brittleness pose compaction challenges. This study introduces an ultrasonic vibration-assisted cold pressing (UVP-CP) technique, which promotes particle rearrangement and interlocking by reducing interparticle friction, enabling the fabrication of dense powder cores under reduced forming pressure. Compared with conventionally cold pressed cores fabricated from the same powder system, the UVP-CP samples exhibit improved soft magnetic performance, achieving an effective permeability (µ_e) of 47.8 at 10 MHz and a core loss of 175.8 mW/cm³ at 50 mT/100 kHz. These values represent a 21.0% improvement in permeability and a 43.4% reduction in core loss over conventional counterparts, establishing a new paradigm for high performance integrated inductor fabrication.