纳米及传统微米级热障涂层热循环过程中的组织演变研究  

Study on the Microstructure Evolution of Nano and Micron-size Thermal Barrier Coatings during Thermal Cycling

作　　者：周莉[1] 白宇[1] 唐健江[2] 韩志海[2] 

机构地区：[1]西安航空发动机(集团)有限公司 [2]西安交通大学金属材料强度国家重点实验室,西安710049

出　　处：《热喷涂技术》2013年第1期16-21,共6页Thermal Spray Technology

摘　　要：本文以超音速等离子喷涂方法沉积NiCoCrAlY金属粘结层,以普通大气等离子喷涂沉积纳米及微米级YSZ两种陶瓷表层,并对涂层进行热循环实验,对比研究不同结构热障涂层在热循环条件下的组织演变规律。结果表明:由于纳米团聚粉体的不充分熔化导致纳米涂层中存在较多的微裂纹和孔隙,微米、及纳米涂层的孔隙率分别为10%及15%,载荷300g下的显微硬度分别为776.1及606.9。两种结构的热障涂层在热循环过程中均出现了网状裂纹,但随着热循环次数的增加,这些微裂纹不断连接扩展,裂纹宽度不断增加,并且与纳米涂层相比,微米涂层裂纹的扩展和拓宽速度相对较快。纳米涂层由于孔隙率较高,热生长氧化物(TGO)生长速度较快,TGO的快速生长导致陶瓷层/金属粘接层界面的应力增大,使得横向裂纹(平行于陶瓷层/金属粘接层界面)萌生及扩展并引起涂层的剥落失效。The bond coatings were fabricated by Supersonic plasma spraying with NiCoCrA1Y, the conventional and nano-structured YSZ thermal barrier coatings （TBCs） were prepared by Atmosphere plasma spraying（APS）, the microstructure evolution laws of two different TBCs were compared under the thermal cycle conditions. The results show that there is lots of microcrack in the nano-structured coating with 15% void content because of incomplete melding of agglomerated nanopowder, while the void content of conventional coating is 10%. Under the loading of 300g, the micro-hardness of nano-structured coating is 776.1 and that of conventional coating is 606.9. Resillage appeared in these two coatings during the thermal cycle process and connected with each other as the number of cycles increasing, the width of crack was extended finally. Compare with nano-structured coating, the crack in conventional coating extended and broadened faster. Thermally grown oxide（TGO） in nano-structured coating grows faster because of the higher void content, then the stress between top coating and bond coating increasing, transverse crack （ parallelling with the interface between top coating and bond coating） appeared and extended, eventually resulted in coating failure with spalling.

关 键 词：热障涂层 TGO 热循环 组织演变 

分 类 号：TG174.4[金属学及工艺—金属表面处理]