Abstract In order to enhance the microwave-absorbing and shielding properties of the composites, the flaky FeSiAl particles embedded in an epoxy polymer were aligned with a two-dimensional rotating magnetic field. The morphologies, electromagnetic (EM) characteristics, and microwave-absorbing and shielding properties of the unaligned and aligned FeSiAl/epoxy composites were investigated. The results showed that after alignment treatment, the flaky FeSiAl particles tend to orient uniformly in the rotating magnetic field, and the permittivity and permeability of the aligned composites were increased in the frequency range of 1–18 GHz compared with that of randomly distributed composites. The calculated microwave-absorbing properties indicated that the peak value of the return loss (RL) of the aligned composites can reach 8.8 dB, compared with 5.8 dB of the unaligned composites of 2.5 mm in thickness (60 wt%); and the bandwidth with RL value more than 6 dB is in a wider frequency range from 1 to 2.8 GHz. And the calculated shielding effectiveness (SE) of the aligned composites is 1.1–3 times higher than that of unaligned one in every thickness, and the maximum SE of the aligned one is 31.8 dB at 18 GHz with a thickness of 2.5 mm.

中文翻译：

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用二维旋转磁场排列片状 FeSiAl 颗粒以提高复合材料的微波吸收和屏蔽性能

摘要 为了增强复合材料的微波吸收和屏蔽性能，将片状FeSiAl颗粒嵌入环氧聚合物中，并在二维旋转磁场中排列。研究了未对齐和对齐的 FeSiAl/环氧树脂复合材料的形貌、电磁 (EM) 特性以及微波吸收和屏蔽性能。结果表明，取向处理后，片状FeSiAl颗粒在旋转磁场中趋于均匀取向，取向复合材料的介电常数和磁导率在1-18 GHz频率范围内比随机分布的复合材料有所提高。计算的微波吸收特性表明，对齐复合材料的回波损耗 (RL) 的峰值可以达到 8.8 dB，而 5。8 dB 厚度为 2.5 mm 的未对齐复合材料（60 wt%）；RL值大于6dB的带宽在1-2.8GHz更宽的频率范围内。并且计算出的对齐复合材料的屏蔽效率（SE）在每个厚度上都比未对齐的高 1.1-3 倍，并且对齐的复合材料在 18 GHz 下的最大 SE 为 31.8 dB，厚度为 2.5 mm。