电纺SiBCN纤维的分子结构设计、先驱体合成及其高温损伤机理研究

SiBCN纤维是一种非常新颖的陶瓷纤维，具有已知的非氧化物陶瓷纤维中最高的高温强度保持率和最优异的抗氧化性能。其室温强度高达4.0GPa，模量390GPa；在1800℃非氧化气氛和1500℃空气中长时间保温后，强度无明显退化。因此该纤维在航空航天防热领域极具应用潜力。正因为其新颖性，合成技术还有待改进、合成和高温损伤机理还急需深入分析，尤其是其在高温烧蚀等方面的研究还处于空白。本项目的目的就在于选用新的有机单体合成出SiBCN先驱体，摸清其合成机理；采用静电纺丝技术获得连续的SiBCN陶瓷纤维，研究原材料种类、合成路径、不熔化处理工艺等参数对其组织结构、价键种类及含量、高温强度保持率、高温晶化行为和抗氧化性能等的影响规律。在此基础上，将其取代现有某型号导弹弹头端帽中的陶瓷纤维，进行性能对比，获得该纤维在高温烧蚀状态下的损伤行为，掌握其损伤机制，为其在航天防热部件上的应用提供数据依据。

SiBCN fiber is a novel kind of ceramic fiber, which has highest strength retention rate and oxidation resistance at high temperature among the nonoxide ceramic fibers that has been known. The fracture strength and Young's modulus of SiBCN ceramic fiber are as high as 4.0GPa and 390GPa. The strength has no obvious degradation when servicing at nonoxidizing atmosphere under 1800℃ or 1500℃ in air for a long time, for this reason, SiBCN ceramic fiber has extremely potential applications in the field of thermal protection of aeronautics and astronautics. For its novelty, the synthetic technique need to be improved, the synthetic mechanism and high-temperature damage mechanism need to be further analysed, especially research on high temperature ablative are still blank in our nation. This project mainly aims at synthetizing SiBCN precursor with novel organic monomers and studying the synthesis mechanism, obtaining continuous SiBCN ceramic fiber with electrospinning technique and studying the influence of these parameters such as raw materials, synthesis route, unmelted treatment process etc. on the organization structure, bonding type and content, high-temperature strength retention rate, high-temperature crystallization behavior and oxidation resistance. SiBCN ceramic fiber will replace the ceramic fiber existing in models of warhead end cap products on this basis, comparing these properties, obtaining the damage behavior and mechanism in the condition of high temperature and ablation and providing data on the applications of thermal protection components in the field of aeronautics and astronautics.