Abstract Al2O3-Y2O3 composite powder with TiO2 additive was plasma sprayed to prepare Al2O3-Y2O3 composite coatings. The microstructure and properties evolution of the Al2O3-Y2O3 coatings during high temperature and thermal shock resistance were investigated. The results show that the microstructure of the Al2O3-Y2O3-TiO2 coating was more uniform than that of the Al2O3-Y2O3 coating. Meanwhile, amorphous phase was formed in the two coatings. The Al2O3-Y2O3(-TiO2) coatings were heat treated for 2 h at temperatures of 800 °C, 1000 °C and 1200 °C, respectively. It was found that the microstructure and properties of the two coatings had no obvious change at 800 °C. Some of the amorphous phase was crystallized at 1000 °C, and meanwhile Y2O3 and Al2O3 reacted to form YAG phase and YAM phase. At 1200 °C, all of the amorphous phases were crystallized. After heat treatment, the microhardness of the two coatings was increased. The thermal shock resistance of the Al2O3-Y2O3 system coatings could be improved by using TC4 titanium alloy as substrate and with NiCrAlY bonding layer. Moreover, the Al2O3-Y2O3-TiO2 coating exhibited better thermal shock resistance due to the addition of TiO2.

中文翻译：

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等离子喷涂Al2O3-Y2O3复合涂层的高温抗热震性能演变

摘要 采用等离子喷涂添加TiO2 添加剂的Al2O3-Y2O3 复合粉末制备Al2O3-Y2O3 复合涂层。研究了Al2O3-Y2O3涂层在高温和抗热震性下的微观结构和性能演变。结果表明，Al2O3-Y2O3-TiO2涂层的微观结构比Al2O3-Y2O3涂层更均匀。同时，在两个涂层中形成了非晶相。Al2O3-Y2O3(-TiO2)涂层分别在800℃、1000℃和1200℃的温度下热处理2小时。发现两种涂层的微观结构和性能在800℃下均无明显变化。一些非晶相在 1000 ℃结晶，同时 Y2O3 和 Al2O3 反应形成 YAG 相和 YAM 相。在 1200 °C 时，所有非晶相都结晶。热处理后，两种涂层的显微硬度均有所提高。以TC4钛合金为基体并加入NiCrAlY结合层可以提高Al2O3-Y2O3体系涂层的抗热震性。此外，由于添加了 TiO2，Al2O3-Y2O3-TiO2 涂层表现出更好的抗热震性。