不同形状特征的碳基复合材料吸波性能分析

Analysis on absorption properties of carbon-based composite materials with different shape characteristics

基于短切碳纤维、碳纳米纤维、石墨烯及炭黑,分析研究碳基复合材料中吸收剂形状比对电磁特性,尤其是吸波性能的影响。采用矢量网络分析仪测试基于不同形状比吸收剂形成碳基复合材料的电磁参数,并且计算出样品理论反射损耗。结果发现,随着频率的增加,碳基复合材料的介电常数逐渐减小;碳纳米纤维样品厚度为2 mm,在8 GHz时反射损耗达到-8 d B;炭黑与石墨烯质量比为1∶1时,在0. 5~12. 8 GHz频段内损耗角正切tanδ随频率的增大而增大且样品厚度为2mm时,其在12~16. 2 GHz反射损耗小于-10 d B,且在12. 8 GHz时反射损耗达到-22. 5 d B。通过对不同形状比吸收剂形成碳基复合材料的电磁参数分析,发现具有一定长径比或较大比表面积的吸收剂复合有利于提升碳基复合材料的吸波性能。

Based on short carbon fiber,carbon nanofiber,graphene and carbon black,here was analyzed the shape ratio effect of the absorber in the carbon-based composite materials on the electromagnetic properties,especially the absorbing properties.The electromagnetic parameters of the carbon-based composites material filled with absorbents of different shape ratios were extracted by a vector network analyzer,and the theoretical reflection loss was calculated.It is found that the dielectric constant of carbon-based composites decreases as frequency increases.When the thickness is 2 mm for the carbon nanofiber samples,the reflection loss is-8 dB at 8 GHz.When the mass ratio of carbon black to the graphene is 1∶1,the loss tangent increases with frequency from 0.5 GHz to 12.8 GHz,and the reflection loss is less than-10 dB from 12 GHz to 16.2 GHz.When the sample thickness is 2 mm for the carbon black/graphene sample,the reflection loss reaches to-22.5 dB at 12.8 GHz.By analyzing the shape ratio effect of absorbents,it is found that the absorbents with certain aspect ratio or large specific surface area could improve the electromagnetic wave absorbing properties of carbon-based composite materials.