Abstract The carbon nanotubes/SiO2-coated carbonyl iron (CNTs/CI@SiO2) composites were fabricated as microwave absorption materials (MAMs) by a simple mechanical mixing method for the purpose of the MAMs with lightweight, thin thickness, broad bandwidth and high oxidation resistance. The effects of different concentration of CNTs on the electromagnetic properties of the CNTs/CI@SiO2 composites were investigated. The results indicate that the complex permeability does not change obviously with the increasing concentration of CNTs because of the constant concentration of CI@SiO2 in the composites. While the complex permittivity and attenuation constant increase with the increasing concentration of CNTs, and the impedance matching ratio decreases with the increasing concentration of CNTs. The reflection loss (RL) calculation results show that 2 wt% CNTs mixed with 65 wt% CI@SiO2 has the optimum microwave absorption properties. The minimum RL is −51.54 dB at 15.44 GHz with a matching thickness of 1.41 mm. The bandwidth corresponding to the RL below −10 dB is more than 6.08 GHz with a thickness of 1.5 mm. The enhanced microwave attenuation ability, improved impedance matching in air-absorber interface and the quarter-wavelength cancellation are believed to contribute the excellent microwave absorption properties of the CNTs/CI@SiO2 composites.

中文翻译：

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碳纳米管和SiO 2 包覆羰基铁微波吸收剂增强的电磁性能

摘要 碳纳米管/SiO2 包覆羰基铁（CNTs/CI@SiO2）复合材料作为微波吸收材料（MAMs），通过简单的机械混合方法制备，以实现轻质、薄厚度、宽带宽和高氧化性的 MAMs。抵抗性。研究了不同浓度的CNTs对CNTs/CI@SiO2复合材料电磁性能的影响。结果表明，由于复合材料中 CI@SiO2 的浓度恒定，复合材料的渗透率不会随着 CNTs 浓度的增加而发生明显变化。而复介电常数和衰减常数随着CNTs浓度的增加而增加，阻抗匹配比随着CNTs浓度的增加而降低。反射损耗 (RL) 计算结果表明，2 wt% CNTs 与 65 wt% CI@SiO2 混合具有最佳的微波吸收性能。最小 RL 在 15.44 GHz 时为 −51.54 dB，匹配厚度为 1.41 mm。-10 dB以下RL对应的带宽大于6.08 GHz，厚度为1.5 mm。增强的微波衰减能力、改善的空气吸收器界面阻抗匹配和四分之一波长抵消被认为有助于 CNTs/CI@SiO2 复合材料的优异微波吸收性能。