Effect of Added Dosage of FeSi Magnetic Powder on the Performance of FeSiAl/FeSi Composite Magnetic Powder Cores

After insulation coating the FeSiAl magnetic powder (Fe−9.6%Si−5.4%Al, D₅₀=32.46 μm) and FeSi magnetic powder (Fe−6.5%Si, D₅₀=19.76 μm) obtained by atomization method, and then FeSiAl/FeSi composite magnetic powder cores were prepared by compounding the two. The effect of the added dosage of FeSi magnetic powder on micro-morphology and magnetic performance of the FeSiAl/FeSi composite magnetic powder cores was investigated. The results demonstrate that the surface of the magnetic powder can form a tightly wrapped insulation layer after insulation treatment. Adding an appropriate amount of the FeSi magnetic powder to FeSiAl magnetic powder can improve the volume density and effective magnetic permeability of the composite magnetic powder core. The DC superposition characteristics of the composite magnetic powder core are significantly improved, but the power loss increases to varying degrees. When the mass fraction of FeSi magnetic powder is 20%, the composite magnetic powder core has the optimum magnetic performance, with an effective permeability of 59.4 at a frequency of 100 kHz, a DC superposition characteristic of 64.3% at a DC magnetization magnetic field of 7962 A/m, and a power loss of 181.5 mW/cm³ at 50 kHz and 100 mT.