Assessment of Binder Content and Particle Size Effects on Core Loss in Fe-Si Powder Cores for Broad Frequency Range

The crystal structure and magnetic properties of Fe- 3.5 wt.% Si (Fe-Si) powder cores, varying in binder contents and median particle sizes, were examined to evaluate the influence of these factors on the core loss. With a median particle size of 10 μm, the core containing 1.0 % binder content exhibited the lowest core loss across a broad frequency range, potentially due to reduced eddy current within the cores. Conversely, with a fixed binder content of 1.0 %, core loss significantly varied with median particle size. The smallest particle size resulted in the lowest core loss in the high frequency range, which might be attributed to diminished eddy current loss. Specifically, a median particle size of 10 μm showed a core loss value of 20.7 J/m³ at 100 kHz and 100 mT, slightly lower than the previously reported 23.0 J/m³. These findings indicate that by optimizing binder content and particle size, Fe-Si powder cores can be effectively tailored for use across a wide frequency range.