短切中空多孔碳纤维复合材料的吸波性能

Microwave Absorbing Properties of Short Hollow Carbon Fiber Composites

以中空多孔聚丙烯腈(PAN)原丝为原料,通过预氧化处理和碳化处理工艺制备了中空多孔碳纤维,采用SEM和XRD对其微观结构和晶体结构进行了表征,并对其吸波性能进行了分析.研究结果表明,中空多孔碳纤维是一种非石墨结构的电损耗型雷达波吸收剂;随着短切中空多孔碳纤维体积分数的提高,随机分布的纤维/石蜡复合吸波材料的介电常数随之增大;用所得的电磁参数结果计算了不同厚度材料的反射率,在2～18GHz频率范围内,当体积分数为33.30%,厚度为2mm时,最低反射率为-21.36dB,其中<-5dB的反射率带宽为5.17GHz,<-10dB的反射率带宽为2.88GHz.

In order to get lightweight radar wave absorbers, hollow carbon fibers were prepared from polyacrylonitrile （PAN） hollow fibers by thermo-oxidative stabilization in air and carbonization in nitrogen. The microstructure and microwave absorbing properties of the resultant PAN-based hollow carbon fibers （PAN-HCFs） were studied by SEM, XRD and voter network analyzer. The reflectivity was simulated by using RAMCAD software. Results show that the electromagnetic parameters of the absorbing materials increase with increase of the PAN-HCFs volume fraction. The reflection coefficient apex moves to lower frequencies with the thickness of absorbing material increasing. With increase of volume fraction of the PAN-HCFs, the reflection coefficients increase greatly and the optimal thickness decreases at the same time. It is found that the 2mm thick composites containing 33.30% PAN-HCFs has an absorbing bandwidth of 5.17GHz below -5dB and 2.88GHz below -10dB in the frequency range of 2-18GHz.The lowest reflection is -21.36dB at 10GHz. The PAN-HCFs are proved to be a light conductive radar absorbing materials in view of its hollow structures and microwave absorption properties.