羰基铁粒径和填充含量对电磁波吸收性能的影响及其研究

Study on the Influence of Carbonyl Iron Particle Size and Filling Content on Electromagnetic Wave Absorption Performance

摘要: 本文以球型羰基铁为磁性吸收剂，硅橡胶为基体，选择粒径尺寸和填充含量为变量，测试2 GHz~18 GHz电磁参数数据，计算1.5 mm厚度下的电磁波衰减系数和反射率，旨在系统探索粒径和填充含量对吸波性能的调控机制。结果表明，羰基铁粒径的减小使比表面积增大，复介电常数影响明显，改善了阻抗匹配，反射率吸收强度增强，D50 ≤ 3 μm粒径时吸波材料反射率在4.24 GHz处反射率峰值为−18.5 dB；相同粒径羰基铁填充含量越高，复介电常数和复磁导率提升明显，电磁波衰减系数显著增大，89%含量在18 GHz处衰减系数达135.7 dB/cm，但介电常数的激增导致吸波材料表面阻抗失配，电磁波吸收峰向低频移动，且反射率峰值由80%含量时的−35.3 dB升高至−16.8 dB，有效吸收带宽变窄。本研究探究了“粒径/填充含量–电磁参数–吸波性能”的关联关系，为吸波材料调控设计提供研究基础。

Abstract: Spherical carbonyl iron was adopted as the magnetic absorber and silicone rubber as the matrix in this work. Particle size and filling content were set as variable factors. Electromagnetic parameters within the frequency range of 2 GHz~18 GHz were measured, and the electromagnetic wave attenuation coefficient and reflection loss under a thickness of 1.5 mm were calculated to systematically investigate the regulation mechanism of particle size and filling content on wave absorption performance. The results reveal that reducing the particle size of carbonyl iron increases its specific surface area, imposes a prominent effect on complex permittivity, optimizes impedance matching, and strengthens the absorption intensity of reflection loss. For carbonyl iron with D50 ≤ 3 μm, the minimum reflection loss of the wave-absorbing material reaches −18.5 dB at 4.24 GHz. For carbonyl iron of identical particle size, higher filling content directly raises the complex permittivity and complex permeability, which drastically increases the electromagnetic wave attenuation coefficient; the attenuation coefficient reaches 135.7 dB/cm at 18 GHz at a filling content of 89%. Nevertheless, the sharp rise in permittivity causes impedance mismatch on the surface of wave-absorbing materials. The electromagnetic wave absorption peak shifts toward low frequencies, the minimum reflection loss rises from −35.3 dB (80% filling content) to −16.8 dB, and the effective absorption bandwidth narrows accordingly. This study explores the correlation of “particle size/filling content-electromagnetic parameters-wave absorption performance”, providing theoretical and experimental foundations for the regulation and design of wave-absorbing materials.