Ni0.4Co0.2Zn0.4Fe2O4/BaTiO3纳米纤维双层吸波涂层的微波吸收特性研究

摘要

BaTiO3 (BTO) nanofibers (NFs) and Ni0.4Co0.4Zn0.4Fe2O4 (NCZFO) NFs with average diameters of about 180 nm and 220 nm, respectively, were prepared by electrospinning method. Their phase structures, surface morphologies and electromagnetic parameters were characterized by X-ray diffraction (XRD), field mission scan-ning electron microscope (FESEM) and vector network analyzer. Microwave absorption properties of both single- and double-layer silicone rubber based absorbing coatings with either 70wt% BTO NFs or NCZFO NFs as micro-wave absorbents were evaluated according to the transmission line theory in the frequency range of 2–18 GHz. The results show that the double-layer absorbing coatings with the NCZFO NFs/silicone rubber composite (S1) as matching layer and the BTO NFs/silicone rubber composite (S2) as absorbing layer display superior microwave absorbing performance compared to the single-layer ones due to the proper combination of magnetic loss of NCZFO NFs and dielectric loss of BTO NFs, and the improved impedance matching characteristics. The double-layer absorb-ing coatings have a reflection loss (RL) of less than –20 dB over the frequency range of 4.9–18 GHz through appro-priately adjusting the thicknesses of the absorbing layer and matching layer. When the thicknesses of the absorbing layer and the matching layer are 2.3 and 0.5 mm, respectively, the minimum RL reaches –87.8 dB at 9.5 GHz and the absorption bandwidth with the RL values below –20 dB is up to 5 GHz. The optimal NCZFO NFs/BTO NFs double-layer absorbing coatings can become a novel microwave absorption material with strong-absorption and broad-band.%采用静电纺丝法制备了平均直径分别为180 nm和220 nm的BaTiO3(BTO)和Ni0.4Co0.2Zn0.4Fe2O4(NCZFO)纳米纤维, 使用X射线衍射(XRD)、场发射扫描电镜(FESEM)和矢量网络分析仪(VNA)对纤维的物相结构、表面形貌和微波电磁参数进行了表征, 并根据传输线理论分析评估了以 BTO和 NCZFO纳米纤维为吸收剂的硅橡胶基单层和双层结构吸波涂层在2~18 GHz范围内的微波吸收性能.结果显示,由于BTO纳米纤维的介电损耗与NCZFO纳米纤维的磁损耗的有机结合和阻抗匹配特性的改善, 以NCZFO纳米纤维/硅橡胶复合体(S1)为匹配层、BTO纳米纤维/硅橡胶复合体(S2)为吸收层的双层吸波涂层比相应单层吸波涂层表现出更为优异的吸收性能.通过调节匹配层与吸收层的厚度,在4.9~18 GHz范围内反射损耗可达–20 dB以下;当吸收层和匹配层的厚度分别为2.3 mm和0.5 mm时,最小反射损耗位于9.5 GHz达–87.8 dB,低于–20 dB的吸收带宽为5 GHz.优化设计的NCZFO/BTO纳米纤维双层吸波涂层有望发展成为一种新型的宽频带强吸收吸波材料.