稀土钽酸盐陶瓷热障涂层的研究进展

摘要

Thermal barrier coatings ( TBCs) are one of the most important materials to keep high efficient gas turbine engines working stably.The effects of TBCs are to improve the corrosion resistance and operating temperature of gas turbine, reduce the fuel consumption and extend turbine lifetime, etc.The current TBCs are yttria stabilized zirconia ( YSZ) , there are some limitations of YSZ, such as, the operating temperature of YSZ is less than 1200℃due to volume change caused by phase transition, which lead to coatings failure.It is urgent for us to develop new kind of TBCs.There are several kinds of TBCs with better thermal conductivity or thermal expansion coefficient than YSZ, but YSZ exhibits better mechanical properties than these potential thermal barrier coatings ceramics, which depends on the ferroelastic properties of YSZ.Rare earth tantalates are a new kind of ferroelastic materials, its operation temperature is up to 1600 ℃. Furthermore, rare earth tantalates exhibit excellent high temperature phase stability, outstanding mechanical properties and minor volume change caused by phase transition, etc.As for thermophysics properties, the thermal conductivity of rare earth tantalates is lower than YSZ and other TBCs ceramics.Thus, rare earth tantalates are proposed as next generation thermal barrier coatings of gas turbine engines .%热障涂层材料是高效燃气轮机稳定工作最重要的材料之一.在燃气轮机使用中不仅能达到抗腐蚀、 提高工作温度的目的,还可以减少燃油消耗,延长发动机使用寿命等.目前广泛使用的热障涂层材料是氧化钇稳定氧化锆(YSZ),其具有一定局限性,在高温下YSZ发生相变体积变化致使涂层失效,因此使用温度在1200℃以下,发展新型热障涂层材料势在必行.现有的其他类型热障涂层材料虽然在热导率或热膨胀系数等方面优于氧化钇稳定氧化锆,但后者具有优异的力学性能,这是由其铁弹性决定的.而稀土钽酸盐作为一种新的铁弹体陶瓷热障涂层材料,除了其使用温度可达1600℃外,兼具有优异的高温相稳定性及力学性能、 相变前后体积变化小等优点,更重要的是其热导率低于YSZ及其它的热障涂层候选材料,这使得稀土钽酸盐陶瓷成为一种新型的热障涂层候选材料.