防CMAS腐蚀热障涂层开裂的研究现状

针对热障涂层在服役过程中受CMAS(Ca O-Mg O-Al2O3-Si O2)腐蚀而造成的表层剥落及层间易开裂问题,探讨总结了CMAS对于热障涂层的腐蚀机理,指出目前所用方法存在的不足,因此急需研究抗CMAS腐蚀的新材料系统和相关工艺。开裂失效是热障涂层主要的失效形式,通过降低氧化层的氧化速度和增加陶瓷层的韧性,能有效延长涂层的使用寿命。基于对涂层结构复杂性的分析,可知涂层需从宏观、细观、微观三个角度进行表述,因此合理运用跨尺度理论对于分析涂层结构等问题有着较为重要的意义。为此提出开发防CMAS渗入的细观增韧的热障涂层,并进一步从跨尺度角度进行开裂分析。研究结果对于丰富涂层增韧途径、增强抗腐蚀性能,保障热障涂层乃至航空发动机的安全平稳运行具有重要的理论意义和工程应用价值。

Research Status on Cracking of Thermal Barrier Coatings against CMAS Corrosion

In view of peeling-off of coating surface and cracking between layers caused by CMAS (CaO-MgO-Al2O3-SiO2) corrosion, the corrosion mechanism of CMAS for thermal barrier coating was discussed. Due to some disadvantages of the currently used methods, it is urgent to study new material systems and related processes to resist CMAS corrosion. Crack failure, as the main failure mode of thermal barrier coating, can be effectively improved by reducing the oxidation rate of the oxide layer and increasing the toughness of the ceramic layer. Based on analysis on complexity of the coating structure, it could be found that the coating needs to be expressed from three perspectives: macroscopic, mesoscopic and microscopic. Therefore, the use of cross-scale theory had important significance for the analysis of coating structure and other issues. For this purpose, it was pointed out that a meso-toughening thermal barrier coating should be developed to prevent CMAS corrosion and coating cracking. The crack analysis for this kind of coating should also be carried out through cross scale. The results are important for enriching of toughening methods and enhancement of anti-corrosion properties of thermal barrier coatings, which can also ensure safe service of thermal barrier coatings and even that of aero engines.