Al2O3/h-BN陶瓷动密封材料的仿生多级结构设计与高温失效机理研究

高温动密封问题已在航空动力装置中日益凸显。自润滑复合陶瓷作为高温动密封件的最佳候选材料之一，亟待进一步提升其力学/摩擦学性能和服役可靠性，并探明材料在典型高温使役条件下的性能退化及密封失效机制。本项目拟仿照贝壳珍珠层的“砖-泥”层叠状和界面微波纹型/微凸起/矿物桥多级结构，以Al2O3陶瓷为基体片层、高温润滑剂h-BN为弱界面层，构建具有高承载、耐磨损、抗高温氧化和耐振动冲击性能的陶瓷基动密封材料，并掌握多级结构对材料高温力学、摩擦学和可靠性能的影响规律，提出材料的微结构调控原理，突破其精细仿生可控制备技术；采用高温动密封模拟测试平台评价材料在热-力-摩擦多因素交互作用下的服役性能，阐明材料微结构/化学组成演化、各项高温性能退化与密封失效的映射关系，揭示其高温退化失效机制，并探索材料的失效控制方法。本项目的实施能够为动密封材料的性能提升和高温可靠性设计提供新思路，并丰富高温润滑与密封理论。

The dynamic sealing problem at high temperature has become increasingly prominent in the aircraft power plant. Self-lubricating composite ceramics as one of the best candidate materials for high-temperature dynamic seals, it is urgent to further improve the mechanical/tribological properties and service reliability of materials, and to explore their performance degradation and seal failure mechanisms under typical high-temperature operating conditions. The project is intended to imitate the “brick-and-mortar” laminated structure and interfacial microwaved structures/micro asperities/mineral bridges hierarchical structures of nacre, and take Al2O3 ceramic as the matrix layer and h-BN as the weak interfacial layer to construct a ceramic dynamic sealing material with high bearing capacity, wear resistance, high-temperature oxidation resistance and vibration impact resistance. Following is to propose the microstructure regulation principle of material by mastering the influence laws of hierarchical structures on the mechanical properties, tribology properties and reliability properties at high temperature, and then to put forward the controllable preparation technology of it. Next is to evaluate the service performance of the material under the interaction effects of heat-force-friction on the high-temperature dynamic seal simulation tester, and clarify the mapping relationship between microstructures/chemical composition evolution, performance degradation and seal failure of material, so as to reveal degradation failure mechanisms of material at high temperature and explore the failure control methods for it. The implementation of this project will provide new strategies for the performance improvement and reliability design of dynamic sealing materials for high-temperature application, and enrich the theory of high-temperature lubrication and sealing.