Fe-Ni/C复合纳米纤维的原位制备与微波吸收性能

采用静电纺丝技术结合稳定化和碳化处理原位制备了Fe-Ni/C复合纳米纤维, 其平均直径约为215 nm, 所生成的Fe-Ni合金纳米颗粒较均匀地分布在碳基纳米纤维的内部和表面, 且被石墨化碳层所包覆. 以Fe-Ni/C复合纳米纤维为吸收剂、 硅橡胶为基质制备成吸波涂层, 研究了碳化温度对电磁特性和微波吸收性能的影响. 结果表明, 涂层厚度为1.2~2.0 mm、 Fe-Ni/C复合纳米纤维质量分数为5%的吸波涂层表现出优良的微波吸收性能, 在7.4~18 GHz频率范围内的反射损耗均低于-20 dB; 随着复合纳米纤维的碳化温度由800 ℃升高到1200 ℃, 由于阻抗匹配特性的改善, 吸波涂层的微波吸收能力逐步加强, 其最小反射损耗由-22.6 dB降低到-63.0 dB.

In-situ Preparation and Microwave Absorption Performances of Fe-Ni/C Composite Nanofibers†

Fe-Ni/C composite nanofibers with an average diameter of about 215 nm were fabricated via an in-situ decomposition and reduction of electrospun polyacrylonitrile/iron acetylacetonate/nickel acetylacetonate precursor fibers during the thermal stabilization and carborization processes. The Fe-Ni alloy nanoparticles in-situ generated during carbonization are well distributed on the surface and inside the nanofibers and encapsulated mostly by the ordered graphitic layers, which can avoid the direct exposure of Fe-Ni alloy phase to air and preserve the structural and interfacial stabilization of Fe-Ni alloy nanoparticles. By dispersing the Fe-Ni/C composite nanofibers homogeneously into a silicone rubber matrix, their electromagnetic parameters were measured in the frequency range of 2—18 GHz and the influences of carbonization temperatures on the electromagnetic characteristics and microwave absorption properties were investigated. It is found that the absorbing coatings containing only 5%(mass fraction) Fe-Ni/C composite nanofibers as fillers with thickness of 1.2—2.0 mm exhibit excellent electromagnetic wave absorbing performances, and the reflection loss(RL) exceeding -20 dB can be obtained over the range of 7.4—18 GHz. The microwave absorption properties for the as-prepared nanocomposites are gradually enhanced with increasing the carbonization temperature from 800 ℃ to 1200 ℃ due to the better impedance match, accompanying with a decrease of the minimum RL values from -22.6 dB to -63.0 dB. Overall, the results reveal that the as-prepared Fe-Ni/C composite nanofibers can be a promising candidate for microwave absorbing materials with strong-absorption, light-weight and thin-thickness in X and Ku bands.