A high-performance soft-magnetic composite (SMC) has been successfully fabricated in a toroidal mold without the application of compaction pressure by mixing three different alumina-coated Fe-based metal powders, namely carbonyl iron (FM), Fe-Si-Cr alloy (FSC), and Fe-Si-Al alloy (sendust), with epoxy resin in a centrifugal paste mixer. Surface coating with an alumina layer was performed via a sol–gel process, and its thickness was controlled by varying the coating time. Without the alumina coating, the SMC toroidal core with a FM:FSC:sendust mixing ratio of 8:22:70 by mass exhibited optimal magnetic properties including an effective permeability (μ_eff) of 33.9 and total core loss (P_t) of 252 mW/cm³ at 100 kHz with an amplitude (B) of 50 mT. With the alumina coating, however, the SMC toroidal core with the same mixing ratio exhibited a significantly reduced P_t value of 213 mW/cm³ while its μ_eff value was slightly decreased to 32.4, primarily due to the suppression of the macroscopic eddy-current loss from 115 mW/cm³ to 85 mW/cm³. These results indicate that an optimal mixture of the three different alumina-coated Fe-based metal powders is very effective for fabricating high-performance SMC cores without external pressure for molding, being applicable for miniature electronic components.

通过混合三种不同的氧化铝涂层的铁基金属粉末，即羰基铁（FM），Fe-Si-Cr，在不施加压紧压力的情况下，已经成功地在环形模具中制造了高性能软磁复合材料（SMC）合金（FSC）和Fe-Si-Al合金（参铝），在离心糊料混合器中与环氧树脂混合。氧化铝层的表面涂覆是通过溶胶-凝胶工艺完成的，其厚度通过改变涂覆时间来控制。无氧化铝涂层，所述SMC环形磁芯与FM：FSC：按质量计的铁硅铝8:22:70混合比表现出最佳的磁特性包括有效磁导率（μ _EFF 33.9）和总铁损（P_吨的252）100 kHz时的mW / cm ³，幅度为（B）为50 mT。与氧化铝涂层，但是，用相同的混合比SMC环形磁芯表现出显著降低P_吨的213毫瓦/平方厘米的值³，而其μ _EFF值略微下降至32.4，这主要是由于宏观eddy-的抑制电流损耗从115 mW / cm ³到85 mW / cm ³。这些结果表明，三种不同的氧化铝涂覆的铁基金属粉末的最佳混合物对于制造高性能SMC磁芯非常有效，而无须模压外部压力，适用于小型电子元件。