We designed unique acicular or octahedral Fe₃O₄/rice husk-based activated carbon (AC) composites in electromagnetic wave (EMW) absorption. The key factors included the carbon layer structure and the regular metal oxide (Fe₃O₄) morphology. Particularly, the experiments involved a thorough ball milling method on biological substrates, which would significantly improve the absorber performance than conventional treated steps. The microstructures were controlled flexibly by adjusting the ratio of activator and magnetizing agent. The formed pores and the regular structures enhanced multiple interface polarizations. The minimum reflectance (R_Lmin) values of sample H4 reached –52.137, –41.918, –51.733, and –47.614 dB at 1.669, 2.002, 2.393, and 3.000 mm, respectively. The R_Lmin values were mainly concentrated in C, X and Kμ bands, and the reflectance (R_L ≤ –10 dB) values covered a wide frequency range of approximately 13 GHz. In summary, the composites had the characteristics of interface engineering, high specific surface area, strong dielectric, and magnetic loss.

我们在电磁波 (EMW) 吸收方面设计了独特的针状或八面体 Fe ₃ O ₄ /稻壳基活性炭 (AC) 复合材料。关键因素包括碳层结构和规则的金属氧化物 (Fe ₃ O ₄ ) 形态。特别是，实验涉及在生物基质上进行彻底的球磨方法，这将比传统的处理步骤显着提高吸收器的性能。通过调节活化剂和磁化剂的比例来灵活控制微观结构。形成的孔隙和规则结构增强了多界面极化。最小反射率 ( R _Lmin) 样本 H4 的值分别在 1.669、2.002、2.393 和 3.000 mm 处达到 –52.137、–41.918、–51.733 和 –47.614 dB。所述ř _LMIN的值主要集中在Ç，X和Kμ带，和反射率（[R_大号 ≤-10分贝）值覆盖约13千兆赫的很宽的频率范围内。综上所述，该复合材料具有界面工程、高比表面积、强介电和磁损耗等特点。