阵列式碳纤维复合材料的制备与微波吸收机理研究

Preparation and microwave absorption mechanism of arrayed carbon fiber composite materials

以碳纤维为代表的碳材料具有质轻、导电性好、化学稳定性强等突出的物理化学性质,将其作为吸波剂使用可以提升材料的吸波性能、使用寿命并有效降低重量。通过“电场取向优化+基体灌封固化”的工艺完成了不同组分阵列式碳纤维复合材料的制备,采用SEM、FT-IR等手段对材料的形貌和化学成分进行表征,利用矢量网络分析仪对材料在2~18 GHz频段内的复介电常数和复磁导率进行表征,分析了微观结构对材料电磁参数、界面阻抗匹配及电磁波吸收性能的影响规律,最后研究碳纤维空间排布形式、复配粉体成分对其吸波性能的影响机制。结果表明,材料的电磁损耗机制由电介质损耗、干涉相消、界面极化弛豫、磁损耗共同构成;当复合材料厚度为2.0 mm时,反射率<-10 dB(6.1~7.6 GHz),在6.5 GHz处最大衰减值为-15.2 dB,热导率达到3.2 W/(m·K);验证所制备的材料在满足电磁波吸收功能的同时还具有一定的导热性。

Carbon materials like carbon fibers have such advantages as light weight,good conductivity and strong chemical stability.It could improve the reflectivity and service life,and it can effectively reduce the weight of the carbon material filled electromagnetic absorbing materials.Here,carbon fibers with array distribution were prepared by the process of"orientation optimization-matrix encapsulation".The morphology and chemical composition of the material were characterized by SEM and FT-IR.The complex permittivity and permeability of the material were measured from 2 to 18 GHz by a vector network analyzer.The effects of microstructure were analyzed on the electromagnetic parameters,interface impedance matching and electromagnetic wave absorption performance.Finally,the effect of arrangement structure,composition and weight ratio on the wave absorption performance was studied through above characterization.It indicates that the electromagnetic loss is due to dielectric loss,interference cancellation,interface polarization relaxation,and magnetic loss.The result show that the reflectivity is less than-10 dB from 6.1 to 7.6 GHz,and the maximum attenuation value and thermal conductivity were-15.2 dB at 6.5 GHz and 3.2 W/(m·K)at 2.0 mm thickness,respectively.