基于三维光子晶体的新型热防护涂层设计与制备技术研究

As long-time flight of hypersonic aircraft in near space, the skin of the aircraft withstands extremely high temperatures due to aerothermal accumulation. But the single thermal protecting manner of traditional thermal protecting coating has low thermal protecting efficiency and cannot keep up with the development of hypersonic aircraft. A thermal protective coating system with both high emissivity and high reflectivity is urgently needed. Therefore, a novel thermal protective coating based on photonic crystal, which can be used to control the light transmission performance at photonic band gap because of their highly ordered microstructures, is designed and used in the project to improve the emissivity and reflectivity of thermal protecting coating in infrared band. This project intensively studies the thermal radiation characteristics of thermal-protective coating based on photonic crystal. By analyzing the effect of type, size of photonic crystal on the reflection, emissivity characteristics under the high temperature condition, the protective mechanism of thermal protective coating based on photonic crystal and the theory about photo-thermal regulating and controlling of high temperature photonic crystal will be proposed. Further the application of related deliverables can be expanded in aerospace engineer.

高超声速飞行器在近空间内长时间飞行过程中，气动热的累积使飞行器的外蒙皮需要承受极高的温度，由于传统防热涂层防热方式单一，不能同时兼具高辐射与高反射性能。基于此，本课题依据光子晶体具有禁带位置高反射率及禁带附近辐射率增强的特点，通过材料结构的高度有序性，获得涂层在近红外波段高反射率和中远红外波段高辐射率，深入研究光子晶体热防护涂层热辐射特性，提高涂层的防热效率；分析光子晶体类型、尺度在高温热环境下对反射、辐射特性的影响，获得光子晶体热防护涂层的热防护机制，建立高温光子晶体光热调控理论体系，拓展相关成果在航天工程上的应用。

本课题利用三维光子晶体具有禁带位置高反射率的特点，设计出适用于在临近空间运行的飞行器的热防护涂层，能够明显提高防护涂层的高温发射率。通过一维模型的导热-辐射传热计算，光子晶体热防护涂层能够阻止3.4%的热量进入临近空间飞行器内部，在100Kw/m2的热流密度下，热防护涂层能够降低530K的内外温差。此外，基于光子晶体光热调控理论，通过合理的设计光子晶体禁带，使光子晶体的带隙中心位于黑体辐射的最大值处，同时尽可能的扩大禁带的带宽，能够有效的提高光子晶体热防护套涂层的热防护能力。在此基础上，我们开展了光子晶体涂层多功能化研究，结果表明，光子晶体涂层具有非常好的抗激光特性和热控性能。此外，通过光子晶体热防护涂层的研究，我们发展了微球合成技术和大面积光子晶体制备技术。通过建立光热调控理论选择合适的功能材料，在对光谱的调节的基础上调控材料的环境热性能。