抗熔融CMAS腐蚀的梯度Y2O3改性ZrO2热障涂层的设计及其功能实现机制

热障涂层（TBCs）是先进航空发动机叶片的关键技术之一。随着高推重比航空发动机的发展，发动机工作温度已经超过了环境沉积物（主要成分为CaO、MgO、Al2O3和SiO2，简称CMAS）的熔点，导致由熔融CMAS引起的涂层性能退化和过早剥落，成为影响发动机叶片热障涂层服役寿命和可靠性的瓶颈。特别是对EB-PVD制备的TBCs而言，其特有的柱状晶间隙会加速熔融CMAS的渗入。本项目团队近期研究发现，稀土改性可以有效提高涂层抗CMAS腐蚀能力，但其作用机理尚不明确，对涂层热循环寿命的影响也亟待研究。鉴于此，本项目提出一种表层富Y2O3、底层低Y2O3的梯度热障涂层设计思路，拟通过研究掌握梯度Y2O3改性ZrO2涂层的设计和制备方法，阐明梯度涂层阻熔融CMAS腐蚀的作用机理和对热循环寿命的影响机理，建立梯度涂层的PA EB-PVD结构优化方法，为长寿命抗高温CMAS腐蚀TBCs的研制提供理论指导。

Thermal barrier coatings (TBCs) technology is one of the key technologies for blades in advanced aero-engines. With the development of engines with high thrust-to-weight ratio, the turbine operating temperatures have exceeded the melting point of engine environmental deposits (The main compositions are CaO, MgO, Al2O3 and SiO2, or CMAS for short). As a result, the coating performance degradation and premature spallation caused by molten CMAS become the bottleneck problems of the service life and reliability of TBCs applied on turbine blades. Especially for TBCs prepared by EB-PVD, the infiltration of molten CMAS is accelerated due to the typical columnar intergranular gaps. In recent work, our group has found that the modification using rare earth oxides can effectively improve the coating resistance to CMAS corrosion. However, the protection mechanism is still unclear and the influence on thermal cycle life of TBCs should be also urgently studied. In view of this, a design thought of novel gradient thermal barrier coating with high Y2O3 content on the top and low content on the bottom is proposed in this project. The design and preparation methods will be mastered through study. The effect mechanisms of the gradient coating on preventing corrosion by molten CMAS and on thermal cycle life will be revealed. And the optimization method of coating structure by PA EB-PVD will be established. These will lay the theoretical foundation for the development of long-life TBCs with good CMAS corrosion resistance at high-temperatures.