仿生中空SiC纤维制备及吸波性能研究

Preparation and Microwave Absorbing Property of Bionic Hollow SiC Fiber

采用静电纺丝法结合碳热还原制备出仿生中空碳化硅纤维。借助XRD、SEM和EDS分析了样品的物相组成和微观形貌,发现纤维物相为β-SiC和少量无定形SiO_(2),纤维呈现出中空结构,纤维直径约为250nm,表面出现纳米孔洞。利用矢量网络分析仪测试了纤维材料2~18GHz频率范围内的电磁参数,结果表明,当纤维填充量为25wt%时,样品的损耗角正切值峰值较大,且具有较高的衰减常数,峰值达到307.87,同时当吸收层厚度为2.2mm时,在16.1 GHz时反射损耗为-34.6dB,有效带宽为8.2GHz。这是由于纤维的中空结构引起微波在材料内部发生多次反射、散射和德拜弛豫,从而赋予材料良好吸波性能。

Hollow SiC fibers were prepared by electrospinning combined with carbothermal reduction method.The phase,structure and microwave absorption property of SiC fiber were studied.The results show the main phase of fiber isβ-SiC and some amorphous SiO_(2).The SiC fiber has a hollow structure and the fiber diameter is about 250 nm,and the nanoholes appear on the SiC fiber surface.The electromagnetic parameters of the hollow SiC fiber were measured by a vector network analyzer and its reflection loss(RL)under different thicknesses were calculated.The results show that when the fiber filling amount is 25%,the sample has the bigger loss angle tangent and a high decay constant of 307.87.By calculating the reflection loss,it is found that its effective bandwidth is 8.2 GHz,and the reflection loss is-34.6 dB at 16.1 GHz as the thickness is 2.2 mm.This is because that the hollow structure of the fiber leads to multiple reflections,scattering and Debye relaxation of microwaves inside the material.