新型宽频带电磁波吸收材料的设计合成及性能研究

The rapid development of wireless communications and high frequency circuit devices in gigahertz range has prompted the study of electromagnetic wave absorbing materials with self-concealing technology, anti-electromagnetic interference and radiation, and microwave darkrooms for civil and military applications. However, the present absorbing materials have serious problems in practical application due to their narrow absorption band-width, high density and weak anti-oxidation. In this project, we will design and prepare new-type nanocomposites as electromagnetic wave absorbing materials, in which metallic nano-magnet with hollow structure will be coated by a high-k dielectric film. The high permeability of metallic magnet will result in thin absorption thickness, and the hollow nanostructure will decrease the material density. The outer dielectric oxide film will reduce the eddy current loss of metallic magnet in electromagnetic wave and avoid the oxidation of inner nano-magnet. The dielectric and magnetic losses were employed to realize wide absorption band. Therefore, the new-type absorption materials with low density, anti-oxidation and wide absorption band (an absorption material will apply for several kinds of electromagnetic wave devices) can be invented. The wide-band absorption will be confirmed by the measurements of the paint layers and composited microwave darkroom compacts, which are prepared by mixing the suitable polymers with the synthesized nanocomposites. Finally, the original research results will be obtained on the fundamental study and preparation methods of new-type electromagnetic wave absorption materials.

电磁波吸收材料在军用"隐形"和民用高频电路、防电磁辐射、抗信号干扰等领域具有重要应用，但现有的电磁波吸收材料还存在频带窄、吸收波段单一、密度大、抗氧化性差等缺点，应用范围受到限制。本项目拟通过电磁介质复合材料的设计与制备，通过键合作用或掺杂的方式将中空纳米金属磁体与高介电氧化物薄膜复合。一方面利用纳米金属磁体高磁导率减少吸收层厚度，中空结构降低材料的密度；外层包裹高介电氧化薄膜抑制涡流损失，利用介电损耗与磁损耗的双重吸波机制实现宽频带电磁吸收；另外，外层氧化物薄膜又能有效地防止内层纳米金属磁体的氧化。从而研制出轻质、抗氧化、多频谱兼容的吸波材料（一种电磁波吸收材料适用于多种频率的设备），将优选出的材料与高分子聚合物复合研制出具有"隐形"功能的特种油漆、涂料、微波暗室用轻质板材等，验证这类新型吸波材料的宽频带吸收性能。最终在新型电磁波吸收材料的基础研究和制备方法上，取得一些原创性研究成果。

电磁波吸收材料在军用"隐形"和民用高频电路、防电磁辐射、抗信号干扰等领域具有重要应用。本项目针对目前国内外研制的电磁波吸收材料普遍还存在频带窄、吸收波段单一、密度大、易氧化等缺点，提出发展电磁介质复合化、抗氧化、多频谱兼容吸波材料的方向。通过研究制备出轻质、宽频带、抗氧化的吸波材料，完成了项目的研究目标。通过电磁介质复合材料的设计与实验，成功地制备出中空纳米磁体与高介电氧化物复合的核-壳结构。电磁波吸收性能测试表明，外层包裹高介电氧化薄膜抑制了涡流损失，介电损耗与磁损耗的双重吸波机制实现了宽频带电磁吸收。此类吸波剂具有中空的特点，因此制备的电磁波吸收材料密度小、质量轻。外层氧化物薄膜又能有效地防止内层纳米金属磁体的氧化，提高了材料的抗氧化能力。通过更进一步研究，这类电磁波吸收材料有望获得实际应用。

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