Melt-coating synthesis FeSiAl@Ba(OH)2 magnetic powder core with enhanced permeability and reduced core loss for high-frequency applications

Soft magnetic composites with enhanced permeability and reduced power loss are urgently needed in the next generation of power electronics and electrical machines. However, traditional insulation techniques suffer from the uneven coating or complex process, which cannot meet these requirements. Here, the feasibility of Ba(OH) 2 as a coating layer of soft magnetic powder is explored. Due to its low melting point, Ba(OH) 2 exhibits good flowability in the molten state, enabling it to evenly coat FeSiAl particles and fill interparticle gaps, thereby forming a uniform, dense insulating layer. This novel coating strategy improves the formability of the magnetic powder cores and optimizes the cores’ soft magnetic performance. Compared with SMPCs without Ba(OH) 2 coating, FeSiAl@Ba(OH) 2 SMPCs have higher magnetic permeability (μ e  = 59.5), higher quality factor ( Q max  = 127.3), lower high-frequency power loss ( P cv  = 2062.9 mW/cm 3 @1 MHz and 50 mT), and good DC bias performance. Our results provide a new approach for the design of insulation coatings for SMPCs, demonstrating significant application potential for high-frequency electronic devices.