轻薄炭黑涂层的制备及其微波吸收性能研究

利用混合强酸对炭黑(CB)进行氧化处理，并以有机硅树脂为基体制备了CB涂层。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、矢量网络分析(VNA)等方法对制备的4种不同填充量的涂层样品进行微观结构和电磁性能表征。微观结构分析表明：CB颗粒尺寸为纳米级，直径大小约为60 nm，氧化处理后的表面形态呈“褶皱”状；制备的CB涂层表面平整、厚度均匀，密度仅为1.1 g/cm3，兼具轻质柔性的特征。微波反射率测试结果显示，在8～18 GHz范围内，涂层样品均表现出了优异的微波吸收性能。当填充量为3.7%时，厚度仅为1.6 mm的涂层有效吸波频宽达到5.13 GHz，吸波强度为-26.5 dB；当填充量为2.3%时，厚度为1.9 mm的涂层有效吸波频宽达到最大值(5.44 GHz)，覆盖整个Ku波段，厚度为2.5 mm的涂层有效吸波频宽为4.44 GHz，覆盖整个X波段。

Preparation and microwave absorption properties of light and thin carbon black coating

Carbon black (CB) was oxidized by using mixed acids, and CB coatings were prepared using silicone resin as the matrix. The microstructure and electromagnetic properties of the as-prepared coating samples with four different filler loadings were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vector network analysis (VNA). Microstructural analyses show that the size of CB particles is nano-scale, the diameter is about 60 nm, and the surface morphology after oxidation treatment is pleated. The prepared CB coatings possess a flat surface and uniform thickness, and the density is only 1.1 g/cm3. The coatings have both the lightweight and flexible characteristics. The microwave reflectance test results indicate that the coating samples exhibit excellent microwave absorption properties in the range of 8 to 18 GHz. When the filler loading is 3.7%, the coating with a thickness of only 1.6 mm has an effective absorbing bandwidth of 5.13 GHz and the absorbing intensity of -26.5 dB. When the filler loading is 2.3%, the effective absorbing bandwidth of the coating (1.9 mm) reaches the maximum value (5.44 GHz) and covers the entire Ku band, the effective absorbing bandwidth of the coating (2.5 mm) is 4.44 GHz and covers the entire X-band.