纳米 YSZ 热障涂层高温时效过程中组织演变研究

燃气轮机长期运行过程中,热端部件如燃烧室内壁和前级涡轮叶片长期经受高温火焰冲击,涂层材料会产生时效行为。在时效过程中,热障涂层会发生组织演变,影响涂层性能与寿命。本文对一种高纯纳米YSZ热障涂层进行了不同温度的时效考核,研究材料在高温中组织演变行为,并对涂层孔隙率变化规律进行了热动力学分析。结果表明,在高温过程中,YSZ涂层中残留的纳米界面会进一步融合并逐渐演变为微米晶;受热动力学机制支配,涂层中孔隙闭合消损,造成涂层孔隙率下降。另外,本文还统计分析了涂层的相变行为。

Study on the Microstructural Development of a nano YSZ TBCin High-Temperature Ageing Processes

During a long run of gas turbines, the hot sections like combustion walls and 1st and/or 2nd turbine blades sustain hot flame attack which causes high-temperature ageing effect in coating materials. The ageing on TBCs could cause microstructural development which influences the coating life. In this paper, a high-purity nano YSZ TBC were aged at different temperatures to study the behavior of the microstructural evolution and to analyze the thermodynamic principles of the porosity changes in the coatings. The results show that some residual nano particles would grow to micro grains; controlled by a thermodynamic mechanism, the pores in the coating were gradually closed resulting in the decreasing of the porosity. The phase transformation behavior of the coating materials was also studied.