同轴多孔FeCo基磁性纤维的可控制备与微波损耗机理研究

Increasing demand of military stealth technology and severe electromagnetic (EM) pollution give rise to opportunity of developing microwave absorbing materials. Preparation the efficient microwave absorbers by using the magnetic nano-material is the emphasis and difficulty of the design of microwave absorbing materials in GHz frequency. In order to obtain the magnetic microwave absorbers with wider frequency range of microwave absorbing property and higher strength, a series of FeCo fibers containing different chemical composition with coaxial and porous structure will be prepared by coaxial electrospinning. The influence of electrospinning process parameters and heat treatment conditions on the structure and property of the fibers will be investigated. By discussing the formation mechanisms of coaxial and porous structure, a reasonable structure model is expected to obtain, which will have some reference value for further study of microwave loss mechanism. Novel methods need to present for evaluation the coaxial electrospinning and characterization the profile degree of coaxial and porous fibers. A reliable resonance absorbing model is expected to explain the controllable preparation and microwave loss mechanism of coaxial-porous FeCo-based magnetic fibers, which contains the cross-section structure, saturation magnetization, electromagnetic parameters, reflection and microwave frequency. The research will provide reliable theoretical foundation and technical support to the existing research on the theory of design and the preparation of microwave absorbing materials, Which has considerable significance to the research on the microwave absorbing materials with wider frequency range of microwave absorbing property, lower density, higher strength and thinner thickness. It has important theoretical meaning and realistic value to study the controllable preparation and microwave loss mechanism of coaxial-porous FeCo-based magnetic fibers.

军事隐身技术的需求和电磁污染的日益严重为吸波材料的研究和发展提供了机遇。利用磁性纳米材料制备GHz频段高效微波吸收剂是军用隐身材料设计的重点和难点。针对现有磁性吸收剂在宽频和强吸收方面的不足，本项目拟采用同轴静电纺丝技术，研制不同成分的微纳米同轴多孔磁性FeCo纤维，研究静电纺丝参数和纤维热处理工艺对纤维结构和性能的影响规律，分析同轴多孔结构的形成机制，建立合理的同轴多孔纤维结构模型，提出评价同轴静电纺丝和表征同轴多孔纤维异形度的新方法，建立含同轴多孔纤维结构、饱和磁化强度、电磁参数、反射率和电磁波频率在内的多参数谐振吸收模型，阐明其微波损耗机理，以实现FeCo基同轴多孔纤维的可控制备。本研究将为吸波材料的设计与制备提供可靠的理论基础与技术支持，为研制"厚度薄、质量轻、频带宽、吸收强"的吸波材料提供一种新思路，具有重要的理论意义和实用价值。

军事隐身技术的需求和电磁污染的日益严重为吸波材料的研究和发展提供了机遇。利用纳米技术制备GHz频段高效微波吸收剂是军用隐身材料设计的重点和难点。本项目主要内容：（1）以静电纺丝制备FeCo微纳米纤维为目标，配制了具有可纺性的FeCo前驱体溶液，考察了其可纺性的影响因素，分析了前驱体分子量对溶液粘度的影响规律。以粘度、电导率和表面张力作为衡量指标研究了静电纺丝工艺对初生纤维形貌的影响，在此基础上分析了前驱体、控制和环境因素对获得良好FeCo微纳米纤维的作用，为静电纺丝制备无机微纳米纤维提供了新范例。（2）基于经典Maxwell方程，结合电动力学与复合材料理论，提出一种磁/电同轴纤维结构模型。构建了该模型电磁参数、反射率与纤维内外径、长径比和电导率等形貌特征与内部本征参数之间的关联，并进行了模拟仿真。结果表明磁/电同轴纤维对入射电磁波的耗散能力明显优于单一纤维。具有高电导率、薄外壳和大长径比磁/电同轴复合纤维可作为理想吸收剂的备选材料，为新型微波吸收剂的设计提供了参考。（3）获得一种具有共振吸收峰的轻质宽频吸波材料，当厚度为2.0-2.1mm时，其低于-10dB的带宽有3.02GHz，小于-5dB的带宽有6.79GHz，最低反射率分别为−12.44 dB 和−20.46 dB。在此基础上探讨了微波吸收剂的复合效应和结构效应对微波吸收带宽的影响。比较发现复合效应和结构设计均可引入新的微波损耗机制，二者进行协同有可能产生新的机理，结合复合效应和结构设计可拓宽微波吸收材料的带宽。本项目已发表和录用论文共11篇，其中SCI源刊3篇，EI源刊4篇；授权发明专利1项，实用新型专利授权3项；培养研究生6人，其中已毕业2人。本研究将为吸波材料的设计与制备提供可靠的理论基础与技术支持，为研制“厚度薄、质量轻、频带宽、吸收强”的吸波材料提供新思路，具有重要的理论意义和实用价值。