仿生多孔SiC纳米纤维制备及有序阵列结构与吸波性能研究

The SiC ceramic fibres usually have the low microwave absorption efficiency, which make them difficult meet the new requirement in radar stealth field of the modern military equipment. In view of that, the bionical porous with the ordered arrays structure design concept for the SiC ceramic microwave absorption nanofibers is proposed in this research. The design concept is not only based on the phenomenon of excellent infrared invisible property of polar bear hair with the multicavity hollow structure, but aslo the summary for the development trace of microwave absorption fibers. The microwave absorption property of SiC fibers will be improved by the combination of the approach including nanotechnology, porous structure and orderly array architecture. The bionical porous SiC nanofibers with the ordered arrays architecture will be prepared using non-hydrolytic sol-gel process, electrospinning technique and carbon thermal reduction method. For this objective, the non-hydrolytic SiO2 gels with high activity and organic solubility property will be used as the precursor of electrospinning method. The phase separation composition for the coaxial electrospinning will be selected and optimized, and the gathering unit of electrospinning will be improved. The carbon thermal reduction process will aslo be optimized. The organic solubility nature of non-hydrolytic SiO2 gels with high activity and their influence on the synthesis of SiC fibers using carbon thermal reduction method will be determined. The formation mechanism of the bionical porous structure and the ordered arrays of SiC nanofibers will be explained. The bionical porous and ordered arrays structure characteristics and their effect on the microwave absorption properties of SiC nanofibers will be exploited. The microwave absorption mechanism and application performance of the SiC nanofibers will be analyzed. This research is significantly important and valuable for the national defence consolidation, and also has an excellent potential application in aerospace military fields.

鉴于目前SiC陶瓷纤维微波吸收效率偏低，难以满足现代武器装备雷达隐身新要求。本项目运用仿生结构设计理念，借鉴北极熊毛发精巧多腔中空结构赋予其优异红外隐身性能的现象，总结纤维吸波材料发展轨迹，提出仿生多孔SiC纳米纤维有序阵列的设计构思。综合利用纳米化、多孔结构和有序阵列化提升SiC纤维吸波性能，采用非水解溶胶-凝胶、静电纺丝和碳热还原相结合的技术加以制备。以活性高且有机可溶的非水解SiO2凝胶为前驱体，优选与之匹配的分相组成，利用同轴静电纺丝技术，通过改良纤维收集装置，优化碳热还原制备技术，制备出仿生多孔SiC纳米纤维及其有序阵列。揭示非水解SiO2凝胶有机可溶性本质，确定其活性对SiC碳热还原合成的影响，阐明纤维仿生多孔及有序阵列结构形成过程，明确高效吸波SiC纤维仿生多孔结构及有序阵列特征，揭示其吸波机制及应用性能。本项目对强化国防具有重要研究意义和价值，在航天军工领域应用前景良好。

鉴于目前SiC纤维微波吸收效率偏低，难以满足现代武器装备雷达隐身新要求。本项目运用仿生结构设计理念，借鉴北极熊毛发精巧多腔中空结构赋予其优异红外隐身性能的现象，利用静电纺丝技术能够制备组成和结构可控的陶瓷纤维的优势，提出仿生多孔SiC纳米纤维有序阵列的设计构思，综合利用纳米化、多孔结构、有序阵列化和复合化提升SiC纤维吸波性能。研究了高活性SiO2凝胶非水解合成技术，采用静电纺丝技术制备出SiC实心纤维，优化纺丝工艺合成出多孔SiC纤维，通过改良纤维收集装置得到多孔SiC有序阵列，并利用水热技术获得多孔SiC/NiCo2O4复合纤维。分析测试纤维吸波性能发现，采用静电纺丝技术制备的实心碳化硅纤维具有一定的吸波特性，当吸波涂层厚度为3.0mm时，在9.1GHz下反射率为-24.7dB；多孔SiC纤维中孔结构对电磁波产生的反射、散射及干涉作用，因此其反射损耗进一步增加，有效吸波宽度提高。多孔SiC纤维有序阵列结构可以显著提高吸波性能，当吸波材料涂层厚度为2.5mm时，在11.2GHz下反射率可达-36.5dB。多孔SiC/NiCo2O4复合纤维反射损耗能够达到-36.3dB，但涂层厚度较厚，为7mm。在此基础上，采用静电纺丝技术制备出多孔镁橄榄石、镁铝尖晶石、氮化钛和氮化铌纤维，并测试了其吸波性能。多孔镁橄榄石和镁铝尖晶石纤维没有明显的吸波性能，多孔氮化钛和氮化铌纤维则具有良好的吸波性能，尤其是多孔氮化铌纤维，当吸波涂层厚度为2.0mm时，反射损耗就能够达到-62.3dB，其具有较强的高效吸波应用潜力。本项目对强化国防具有重要研究意义和价值，在航天军工领域应用前景良好。