铁磁金属/钡铁氧体复合吸波材料的双负电磁参数调控

High-performance microwave absorption materials are the key of the stealth technology. As the response of a material to microwave has a close relationship with two parameters: permittivity and permeability, it is very important to get a precisely control of the permittivity and permeability to improve the performance of the microwave absorption materials. However, the adjusting range of the permittivity and permeability is limited to positive value in a narrow range due to the existence of magnetic bounds relation, which restricts the development of the high-performance microwave absorption materials. In this project, we plan to introduce negative permittivity and negative permeability into the microwave absorption materials, which will totally changing the microwave propagation property in the materials. Both experiment and calculation will be used to investigate the relationship among the microstructure, negative electromagnetic parameters and the microwave absorption properties. Including the characterization of the microstructure, investigation of the frequency dispersion of stealth coating’s permittivity and permeability and the prediction of microwave absorption property based on electromagnetic simulation. This project aims to provide both theoretical and experimental supports for the fabrication and application of negative electromagnetic parameters material in microwave stealth coating.

高性能新型吸波材料的研发是隐身技术领域的关键问题，而吸波性能与材料的复介电常数和复磁导率这两个电磁参数密切相关，因此对材料电磁参数的调控是改善吸波性能的重要手段。然而由于磁性材料存在磁极限，绝大多数吸波材料电磁参数的调控范围被限制在一个较窄的正数范围内，严重制约了吸波材料性能拓展的空间。针对该问题，本项目拟利用金属的等离子体振荡，结合磁性材料的低阻尼磁共振特性，将负介电常数及负磁导率纳入微波吸收材料的电磁参数调控范围中，探明电磁波在负电磁参数材料中的传播规律，揭示负电磁参数与微波吸收性能之间的关系，推动负电磁参数材料在隐身涂层领域的工程应用。具体研究内容包括：铁磁金属与钡铁氧体纳米吸波剂的合成及其微观结构表征；复合材料高频及微波电磁参数频散特性的变化规律及其调控；等效电磁参数的计算和吸波性能的优化设计。

高性能新型吸波材料的研发是隐身技术领域的关键问题，而吸波性能与材料的复介电常数和复磁导率这两个电磁参数密切相关，因此对材料电磁参数的调控是改善吸波性能的重要手段。本项目围绕该问题开展了系列研究，成功制备了以铁磁金属纳米纤维为主要功能相的吸波复合材料。通过利用金属的等离子体振荡，结合磁性材料的低阻尼磁共振特性，优化了材料的吸波性能，最大有效吸收带宽接近8GHz。项目研究成果揭示了复合材料的负物性参数归因于逾渗体系的异质性、复合性和临界性。在介电频散方面，亚逾渗组分复合材料介电常数为正值，特征是德拜弛豫；过逾渗组分复合材料可视为功能相中的载流子被基体相稀释，平均电子密度降低，介电常数可出现负值，由等离体振荡所导致。磁性组分低阻尼磁共振和逾渗网络的抗磁性是产生负磁导率的原因。上述研究结果对于材料电磁参数的调控具有重要理论指导意义。在此基础上，借鉴超材料的性能设计思路，探索性开展了复合材料功能相的微结构有序化相关研究，有序化微结构引入的周期性边界条件，可有效简化材料本征模型，实现对材料电磁性能的精准设计，这对于复合材料性能设计与调控，具有重要的实际应用价值。

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