【摘要】 稀土硅酸盐环境障涂层（EBCs）是应用于新一代高推重比航空发动机热端部件的重要材料，但在服役过程中，稀土硅酸盐面层易产生纵向裂纹，为腐蚀性介质进入EBCs体系内部提供通道，使硅黏结层发生氧化并产生裂纹，最终导致EBCs失效。二硅化钼（MoSi₂）具有优异的高温性能，有望改善稀土硅酸盐EBCs体系的高温稳定性。本工作采用MoSi₂改性Yb₂SiO₅面层，通过真空等离子喷涂技术（VPS）分别制备了以Yb₂SiO₅、 Yb₂SiO₅-5%MoSi₂（体积分数，下同）和Yb₂SiO₅-10%MoSi₂作为面层，以Yb₂Si2O₇作为中间层，以Si作为黏结层的三种环境障涂层体系，利用场发射扫描电子显微镜表征了涂层在1350℃热震前后的形貌变化。结果表明：掺杂MoSi₂不仅能改善涂层的损伤容限，还可消耗氧化性介质，减少其向涂层体系内部的扩散，使黏结层上TGO层厚度分别降低83%和88%，从而有效改善涂层体系的高温稳定性。更多还原

【Abstract】 Rare-earth silicate environmental barrier coatings（ EBCs） are important materials for the application in hot end components of new generation high thrust-to-weight ratio aero engines. However, the rare-earth silicate top layer is prone to form longitudinal cracks, which provides a channel for corrosive media to enter the interior of the EBC system, causing oxidation and cracking of the silicon bond layer, ultimately leads to the failure of EBCs under high temperature service environment. MoSi₂ has excellent high-temperature properties and is expected to improve the high-temperature stability of rare-earth silicate EBC systems. In this work, three kinds of EBCs with Yb₂SiO₅, Yb₂SiO₅-5%MoSi₂（Volume fraction,the same below）and Yb₂SiO₅-10%MoSi₂ as the top layer, Yb₂Si2O₇ as the intermediate layer and Si as the binder layer were prepared by vacuum plasma spraying（VPS）technique respectively. The morphological changes of the coating before and after thermal shock at 1350 ℃ were characterized by field emission scanning electron microscopy. The doping of MoSi₂ not only improves the damage tolerance of the Yb₂SiO₅ coating, but also consumes the oxidizing medium and reduces its diffusion into the interior of the coating system, which reduces the thickness of the TGO layer on the bonded layer by 83% and 88% and effectively improves the high-temperature stability of the coating system.更多还原