(1. 南京航空航天大學(xué) 江蘇省精密與微細(xì)制造技術(shù)重點(diǎn)實(shí)驗(yàn)室，南京 210016；
2. 南京航空航天大學(xué) 機(jī)電學(xué)院，南京 210016)
摘 要: 以Al2O3-13%TiO2(質(zhì)量分?jǐn)?shù))團(tuán)聚體復(fù)合陶瓷粉末為材料，采用等離子噴涂工藝在TiAl合金表面制備納米結(jié)構(gòu)陶瓷涂層。用掃描電鏡(SEM)和X射線衍射儀(XRD)分析粉末和涂層形貌、微觀結(jié)構(gòu)及相組成，討論涂層的微觀組織形成機(jī)理。結(jié)果表明：納米結(jié)構(gòu)復(fù)合陶瓷涂層由部分熔化區(qū)以及與常規(guī)等離子噴涂類似的片層狀完全熔化區(qū)組成；根據(jù)組織結(jié)構(gòu)的不同，部分熔化區(qū)又分為液相燒結(jié)區(qū)(亞微米A12O3粒子鑲嵌在TiO2基質(zhì)相的三維網(wǎng)狀或骨骼狀結(jié)構(gòu))和固相燒結(jié)區(qū)(經(jīng)過(guò)一定程度長(zhǎng)大但仍保持在納米尺度的殘留納米粒子)；等離子噴涂使部分α-A12O3以及全部θ-A12O3轉(zhuǎn)變?yōu)閬喎�(wěn)態(tài)γ-A12O3；納米結(jié)構(gòu)復(fù)合陶瓷涂層中的完全熔化區(qū)、液相燒結(jié)區(qū)及固相燒結(jié)區(qū)分別由等離子噴涂過(guò)程中納米團(tuán)聚體粉末中溫度高于A12O3熔點(diǎn)、介于TiO2熔點(diǎn)到A12O3熔點(diǎn)之間以及低于TiO2熔點(diǎn)區(qū)域沉積獲得，納米結(jié)構(gòu)涂層中不同部分熔化組織源于復(fù)合陶瓷粉末中A12O3與TiO2之間的熔點(diǎn)差異。
關(guān)鍵字: Al2O3-13%TiO2納米復(fù)合陶瓷涂層；等離子噴涂；納米團(tuán)聚體粉末；形成機(jī)理
（1. Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology,
Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
2. College of Mechanical and Electrical Engineering,
Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China）
Abstract:The nanostructured ceramic coatings were fabricated on TiAl alloy surface by plasma spraying with agglomerated Al2O3-13%TiO2 (mass fraction) powders. The morphology, microstructure and phase of the powders and coatings were investigated by scanning electron microscopy and X-ray diffractometry. The formation mechanism of the coating was discussed. The results show that the nanostructured ceramic coating consists of the fully melted regions and the partially melted regions, and the fully melted region has a lamellar-like structure as the conventional coating. According to different microsturctures, the partially melted regions are divided into liquid-phase sintered regions such as a three-dimensional net or skeleton-like structure, Al2O3-rich submicron particles distributing in the TiO2-rich matrix, and solid-phase sintered regions such as remained nanoparticles. Partially α-A12O3 phase and all θ-A12O3 phase in the nanostructured powder change to γ-Al2O3 after plasma spraying. The fully melted region, liquid-phase sintered region and solid-phase sintered region of nanostructured composite ceramic coating are derived from the region of the nanostructured agglomerated powders, where the temperature is beyond 2 045 ℃ (melting point of Al2O3), ranging between 1 840 (melting point of TiO2) and 2 045 ℃, and less than 1 840 ℃ during plasma spraying, respectively. The formation of the solid-phase and liquid-phase sintered regions in the partially melted region is attributed to the melting point difference between A12O3 and TiO2.
Key words: Al2O3-13%TiO2 nanostructured composite ceramic coating; plasma spraying; agglomerated powder; formation mechanism
