仿生高温抗砂涂层与自清洁机理

The turbine inlet temperature of aero-engine has exceeded 1500 ℃. Sand in air (melting point about 1200~1650 ℃) will melt and adhere to the surface of turbine components after being absorbed into the turbine, which will result in the blade damage and seriously threaten the engine safety. As desertification in China is nearly half and distributes in strategic areas, the problem of sand is particularly serious. The existing researches mainly focus on preparing and forming a dense layer to prevent the penetration and erosion of the molten sand. However, the coating has a prominent problem of sand sticking and accumulating, which causes the burnout of components has not been solved. This study proposes a multi-layer integrated bionic new structure of imitation onion layer-by-layer gradient combination and imitation lotus leaf micro-nano surface, which combines the dual properties of anti-sand adhesion and sand removal to achieve bionic self-cleaning properties. Firstly, constructing a dynamic adhesion model of high-temperature sand, revealing the self-cleaning mechanism of bionic microstructure structure-performance evolution and clarifying the new coating structure and mechanical design requirements. Secondly, developing a new technology of plasma spray-physical vapor deposition for controlling multiphase unit deposition. Forming a new method of multi-parameter group centralized control, and preparing biomimetic coating. Finally, the high-temperature sand-resistant test will be used to investigate the structure-activity evolution of bionic coatings under high temperature, and reveal the self-cleaning mechanism. The bionic structure high-temperature sand resistant coating proposed in this project has important theoretical value and technical support and is significant for China's independent development of advanced aero-engines.

航空发动机涡轮入口温度已超过1500℃，空气中砂尘（熔点1200~1650℃）将熔化、粘附在涡轮部件表面，导致部件损毁、严重威胁发动机安全，而我国沙化土地占比近半且分布于战略要地，砂尘问题尤为严重。现有研究主要是制备致密表层、阻止砂尘熔渗破坏涂层，但是，最根本的砂尘粘附堆积、导致部件烧毁问题并未解决。本研究提出仿荷叶微纳表面、仿洋葱逐层梯度结合的多亚层一体仿生新结构，将抗粘附、除堆积双模性能有机结合，实现仿生自清洁。首先，构建高温砂尘粘附堆积动态模型，揭示仿生微结构构效演变自清洁机制，阐明新型涂层结构与力学设计要求；其次，发展等离子-物理气相沉积多相态单元沉积调控新技术，形成多参数集联控制新方法，制备仿生涂层；最后，采用高温熔砂沉积试验探究高温下仿生涂层的抗粘/除积演变规律，揭示自清洁机理。本项目提出的仿生高温抗砂涂层，对我国自主发展先进航空发动机核心涂层具有重要理论价值和技术支撑意义。

环境中的砂尘在高温下将熔化、粘附在发动机叶片热障涂层表面，导致涂层失效、严重威胁发动机安全。本项目设计了仿生高温抗砂尘涂层，形成了PS-PVD多相态材料“变频”沉积多参数集联控制方法，并制备了涂层，考核了涂层的抗高温熔融砂尘性能，揭示了其抗粘/除积双模自清洁机理。具体进展如下：首先，构建了高温熔融砂尘粘附/堆积模型，揭示了涂层表面熔融砂尘粘附与砂尘累积导致涂层纵深应力梯度分布的规律，设计了新型仿生抗高温熔融砂尘涂层，并获专利授权；其次，开展了PS-PVD多相态沉积单元“变频”沉积调控技术研究，掌握了沉积单元相态受工艺参数的影响规律，形成了多参数集联控制新方法，实现了新型涂层的制备调控；最后，采用高温熔砂沉积试验研究了涂层表面砂尘粘附行为。研究了表面微纳结构与逐层结合强度对抗高温熔融砂尘粘附堆积行为的影响规律，揭示了涂层表面微纳结构抗粘附、逐层除砂尘堆积的双模自清洁机制。相关成果在Journal of Materials Science & Technology、Journal of Advanced Ceramics等本领域高水平国际期刊发表论文5篇，应邀做国际学术会议分会特邀报告1次和国内学术会议分会邀请报告3次。研究成果对未来发展航空发动机新型高温抗砂涂层技术方面具有潜在应用价值。