中文摘要：

以常规和纳米团聚体Al2O3—13TiO2（ω／％，下同）复合陶瓷粉末为原料，采用等离子喷涂工艺在TiAl合金表面制备常规和纳米结构陶瓷涂层。用扫描电镜（SEM）和X射线衍射（XRD）仪分析粉末和涂层形貌、微观结构及相组成，同时对纳米结构涂层的微观组织形成机制进行了讨论。结果表明：常规复合陶瓷涂层呈典型的等离子喷涂层状堆积特征；纳米结构复合陶瓷涂层由部分熔化区以及与常规等离子喷涂类似的片层状完全熔化区组成。根据组织结构的不同，部分熔化区又分为亚微米Al2O3粒子镶嵌在TiO2基质相的三维网状或骨骼状结构的液相烧结区和经过一定长大但仍保持在纳米尺度的残留纳米粒子的固相烧结区，不同的部分熔化组织源于复合陶瓷粉末中Al2O3与TiO2之间的熔点差异。由于等离子喷涂过程中涂层沉积时的快速凝固作用，不管是常规还是纳米涂层都以亚稳相γ-Al2O3为主。

英文摘要：

The conventional and nanostructured Al2O3-13TiO2 composite ceramic coatings（ω%, similarly hereinafter） were fabricated by plasma spraying on TiAl alloy surface with conventional and nanostructured agglomerated powders as starting materials. The morphology, microstructure and phase composition of the powder and the coating were investigated by means of scanning electron microscopy （SEM） and X-ray diffractometry （XRD）. Meanwhile, the formation mechanism of the coating microstructure was discussed. The results show that the conventional composite ceramic coating presents typical plasma-spraying lamellar accumulation structure. However, the nanostructured ceramic coating consists of not only fully melted regions but also partially melted regions, and the fully melted region has a lamellar-like structure as conventional coating. According to the different microstructure, the partially melted regions can be divided into liquid-phase sintered regions （three-dimensional net or skeleton-like structure： submicron Al2O3 particles distributed in the TiP2 matrix） and solid-phase sintered regions （residual nanoparticles have grown to some extent but still remained nano-scale）. The different partially melted regions come from the difference of the melting point between Al2O3 and TIP2. The main phase, in both the conventional and nanostructured coating, is the metastable phase ofy-Al2O3 due to the rapid solidification during the deposition of plasma spraying.