轻质CB/RGO复合涂层的制备及其吸波性能研究

目的制备吸波性能优异的碳基复合吸波涂层。方法采用液相法在导电炭黑(CB)体系中原位生长还原氧化石墨烯(RGO)材料,合成了CB/RGO复合吸收剂,并以环氧树脂为基体制备了CB/RGO复合涂层。利用扫描电子显微镜(SEM)和透射电子显微镜(TEM)对制备的CB/RGO复合吸收剂进行微观结构表征,研究了吸收剂填充量和厚度对涂层电磁性能的影响规律。结果微观结构分析表明,CB以一种类似“葡萄状”的结构形态附着在石墨烯片层之间,在其表面实现包覆性生长,分散均匀且具有较好的附着力;制备的CB/RGO复合涂层质地均匀,密度仅为1.1 g/cm^3,兼具轻质柔性的特征。微波反射率测试结果显示,在高填充量3.0%和3.7%下,涂层均未表现出明显的强电磁吸收能力,而在低填充量1.6%和2.3%下,涂层表现出十分优异的微波吸收性能。结论当填充量为2.3%、厚度为1.9 mm时,涂层表现出最佳的吸波性能,最大吸波强度为−17.1 dB,有效吸波频宽达到6.63 GHz,覆盖整个测量频段的66.3%,显示出良好的宽频吸波性能。另外,当厚度为2.5 mm时,填充量为2.3%的涂层实现了雷达波在X波段的微波全吸收。

Preparation and Microwave Absorption Properties of Lightweight CB/RGO Composite Coating

The work aims to prepare the CB/RGO composite coating with excellent microwave absorbing properties.Reduced graphene oxide(RGO)was in-situ grown into the conductive carbon black(CB)system for synthesizing the CB/RGO composite absorbent by the liquid phase method,and the CB/RGO composite coatings were prepared by epoxy resin as matrix.The microstructure of the prepared CB/RGO composite absorbent was characterized by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The effect of the amount and the thickness of absorbent on the electromagnetic properties of the coatings was studied.From the microstructure analysis,the CB particles adhered to the graphene sheets with a“grape-like”structure,and achieved coating growth on the surface,which were dispersed evenly and had good adhesion.The prepared CB/RGO composite coatings possessed a uniform thickness and a density of only 1.1 g/cm3,and had both the lightweight and flexible characteristics.The microwave reflectance test results indicated that the coatings had no obvious strong electromagnetic absorption within high filler loadings of 3.0%and 3.7%,while the coatings showed excellent microwave absorption properties within low filler loadings of 1.6%and 2.3%.When the filler loading is 2.3%and the thickness is 1.9 mm,the coating exhibits the best absorbing performance,the maximum absorbing intensity is−17.1 dB,and the effective absorbing bandwidth reaches 6.63 GHz covering 66.3%of the entire measured bandwidth,showing good broadband absorbing performance.In addition,when the thickness is 2.5 mm,the coating with a filler loading of 2.3%realizes full absorption of the radar wave in the X-band.