热障涂层中热生长氧化物与合金粘结层“镶嵌式”界面调控及失效机制

高温水蒸气服役环境和材料物性参数差异会降低热障涂层中热生长氧化物（TGO）与合金粘结层之间的结合强度，从而导致涂层脱落失效。避免TGO和粘结层平整界面的结构缺点，根据断裂力学理论设计和制备阻碍贯穿型裂纹生长的新型界面，是延长热障涂层寿命的关键科学问题。本项目分析和利用高温水蒸气对粘结层的金属氢损伤现象，调控活性元素氧化物生长，形成TGO和粘结层的“镶嵌式”界面，阻碍贯穿失效裂纹形成，从而提高涂层的断裂韧性。本项目拟采用理论计算和实验验证相结合的方法，分析含水气氛预处理对合金粘结层中活性元素Hf扩散的影响以及局部氧化铪的形成机制；揭示“镶嵌式”界面结构的均匀控制方法；研究“镶嵌式”结构对内应力的影响规律；阐释“镶嵌式”界面结构的失效模型。从而形成提高涂层粘结性能的“氢损伤+裂纹形核生长+钉扎氧化物形成”新思路和方法，延长高温含水环境中热障涂层寿命，为我国涡轮发动机技术进步提供一定的基础支撑。

Different parameters of the materials and high-temperature operating environments could reduce the adhesion between thermally growth oxide (TGO) and alloy bondcoat, which could result failure and spallation of the thermal barrier coatings (TBCs). To avoid the structural shortcoming of the planar interface between TGO and bonding layer, it is a key scientific problem to design and prepare a new type of interface according to the theory of fracture mechanics, which hinders the growth of through-wall crack. In this project, we will analyze and utilize the phenomenon of metal hydrogen damage caused by high temperature water vapor to the bonding layer, regulate the growth of RE oxides, form the "mosaic" interface between TGO and the bonding layer, hinders the formation of through-wall cracks, thus improving the fracture toughness of the coating. In this project, theoretical calculation and experiment are adopted to analyze the influence of aqueous atmosphere pretreatment on the Hf diffusion within the alloy bonding layer and the formation mechanism of local hafnia. It will be studied that to reveal the control method of uniform "mosaic" interface structure, to study the influence of "mosaic" structure on internal stress, and to explain the failure model of "mosaic" interface structure. Thus, it will formed a new idea and method of "hydrogen damage + crack nucleation growth + pinning oxide formation", which can improve the bonding performance of the coating. It could increase the TBCs life in high temperature and water containing environment, and provide a certain basic support for the turbine technology development in China.