Magnetic properties and lowering core loss in Fe-Si powder cores in high frequency range

The microstructure and magnetic performance of Fe-6.5 wt% Si soft magnetic powder cores were investigated. Samples annealed up to 1073 K exhibited stable real part of permeability (μ’) across a wide frequency range from 1 kHz to 1 MHz, with the initial value gradually increasing from 52 to 113. Core loss (P_cv) increased with frequency but was strongly dependent on the temperature. The effect of compaction pressure on magnetic properties was also assessed. P_cv separation analysis was conducted to evaluate the mechanisms influenced by compaction pressure. At 50 kHz and 100 mT, the lowest P_cv of 394 kW/m³, combined with a high B_s of 1.56 T and a moderately high permeability of 66, was achieved for the core annealed at 973 K and compacted of 1470 MPa. These findings indicate that Fe-Si powder cores are promising candidates for the power electronic devices operating in the mid-frequency range.