Co含量对轻质微波吸收剂C/Co纳米纤维吸波性能的影响  

Co Content on Absorption Property of C/Co Nanofibers as a Lightweight Microwave Absorber

作　　者：张雪珂 向军[1] 吴志鹏[1] 刘敏[1] 沈湘黔[2] 

机构地区：[1]江苏科技大学数理学院,镇江212003 [2]江苏大学材料科学与工程学院,镇江212013

出　　处：《无机材料学报》2017年第12期1299-1307,共9页Journal of Inorganic Materials

基　　金：国家自然科学基金(51474113)~~

摘　　要：采用静电纺丝法结合热处理制备了一种可应用于2~18 GHz频段的高性能轻质微波吸收剂C/Co纳米纤维,详细研究了金属Co含量对纳米纤维的电磁特性及微波吸收性能的影响。相对于纯碳纳米纤维,C/Co纳米纤维的微波吸收性能得到显著加强,其主要吸波机制仍是介电损耗。随着Co含量的增加,C/Co纳米纤维的电磁衰减能力逐渐下降,而微波吸收却先增强后减弱,含37.8wt%Co的C/Co-5纳米纤维因金属Co粒子和纳米碳纤维的良好结合与协同效应,以及纤维中特殊的Co粒子@石墨核壳结构所带来的良好阻抗匹配与足够高的电磁衰减能力而表现出最好的吸波性能。模拟计算结果表明,涂层厚度在1.1~5.0 mm间变化时,填充5wt%C/Co-5纳米纤维的硅胶吸波涂层的反射损耗(RL)值超过–20 d B的频率范围在3.2~18 GHz,最小RL值达到–78.8 d B,其中当涂层厚度仅为1.5 mm时,RL值低于–20 d B的吸收带宽可达6.0 GHz(12~18 GHz)。C/Co纳米纤维优异的微波吸收性能表明,这些磁性碳杂化纳米纤维有望成为一种极具应用前景的新型吸波材料。C/Co nanofibers （NFs） as a high-performance lightweight microwave absorber in the 2-18 GHz band were fabricated by a facile electrospinning process combined with subsequent heat treatment. The effects of Co content on the electromagnetic characteristics and microwave absorption properties of C/Co NFs were investigated. The microwave absorption performance of C/Co NFs is significantly enhanced as compared to that of pure carbon nanofibers （CNFs） and the primary microwave absorption mechanism is ascribed to the dielectric loss. With increase of Co content, the electromagnetic attenuation capability of C/Co NFs monotonically decreases, while their microwave absorbing ability firstly rises and then drops. The C/Co-5 NFs sample with 37.8wt% Co exhibits the best performance for microwave absorption due to a good impedance matching and sufficiently high electromagnetic attenuation capability, which result from proper combination and synergistic effect between Co particles and CNFs, as well as the particular Co particle@graphite core-shell structure in the NFs. The simulation results show that a reflection loss （RL） exceeding -20 dB is obtained in a wide frequency range of 3.2-18 GHz for the silicone composite contained only 5wt% C/Co-5 NFs by choosing an appropriate layer thickness between 1.1 mm and 5.0 mm, and an optimal RL value of -78.8 dB is obtained at a layer thickness of 2.5 mm. More importantly, when the absorber thickness is as thin as 1.5 mm, the absorption bandwidth （RL≤-20 dB） is up to about 6 GHz ranging from 12 GHz to 18 GHz, which covers the whole Ku-band. The excellent microwave absorption property together with light- weight and ultrathin thickness of C/Co NFs indicate that these magnetic carbon hybrid nanofibers can be used as a novel and promising microwave absorbing material.

关 键 词：C/Co纳米纤维 微波吸收 轻质 静电纺丝 

分 类 号：TM25[一般工业技术—材料科学与工程]