热障涂层与单晶高温合金互扩散控制方法研究进展

Research progress in methods for inhibiting interdiffusion between single crystal superalloys and thermal barrier coatings

目前,二代及更高级单晶涡轮叶片的表面服役温度已达到1050℃以上,因此涂层与基体间的元素互扩散十分严重。互扩散不仅会消耗涂层中的有益元素,降低涂层服役寿命,而且会在单晶基体中形成二次反应区,严重损害单晶基体的力学性能。扩散障和低互扩散性涂层是控制热障涂层与单晶基体间元素互扩散的有效方法。结合国内外最新研究进展,本文首先对扩散障的设计原理、基本特性以及分类作简要介绍,并具体分析了金属扩散障、陶瓷扩散障和活性扩散障存在的主要问题以及针对这些问题开展的相关研究工作;其次,对低互扩散性涂层在热障涂层领域中的应用与最新发展动态进行综述,详细讨论了纳米晶涂层、相平衡涂层和γ′基涂层的高温防护性能和阻扩散机制。在此基础上,指出了扩散障和低互扩散性涂层的未来发展方向。

Currently,the surface working temperature of second-generation or more advanced single crystal superalloy blade is above 1050℃,resulting in serious interdiffusion between coating and substrate.The interdiffusion not only consumes the beneficial elements of the coating and then reduces its service life,but also leads to the formation of secondary reaction zone in the substrate,which will seriously damage the high-temperature mechanical performance of the single crystal superalloy.Preparing diffusion barriers and designing the low inter-diffusivity coatings are effective ways to control the interdiffusion between thermal barrier coatings and single crystal superalloy substrates.Firstly,based on the latest international and domestic research progresses,the design principles,characteristics and classification of diffusion barriers were introduced briefly,and then the main problems and related research studies of metal diffusion barriers,ceramic diffusion barriers and active diffusion barriers were analyzed.Secondly,the application and latest progress of low inter-diffusivity coatings were reviewed,and the high-temperature protection properties and anti-diffusion mechanisms of nanocrystalline coatings,equilibrium coatings andγ′-based coatings were discussed in detail.Finally,the future development directions of different diffusion barriers and low inter-diffusivity coatings were pointed out.