等离子喷涂纳米陶瓷涂层的显微组织及结构分析

Study on Microstnicture and Phase Composition of Plasma Sprayed Nanostructured Zirconia Ceramic Coating

热障涂层由绝热陶瓷层和金属底层组成,是目前保证高温合金在火箭发动机热端部位正常工作的主要技术。应用等离子喷涂方法成功备了纳米氧化锆陶瓷涂层,并对其微观组织形貌及相结构等进行观察分析,探讨了纳米陶瓷涂层的沉积机理。研究表明,涂层中的孔隙主要为长条形和近球形,无贯穿性孔洞;纳米陶瓷涂层裂纹较为细小,无明显的方向性;纳米粉末和涂层均为四方相(t-ZrO2)氧化锆组成的熔融或者部分熔融状态的纳米结构。

Nanostructured zirconia coating as a thermal barrier coating was prepared by plasma spraying of agglomerated nanostructured ZrO2 feedstock. The microstructure and phase composition of the ce-ramic coating were analyzed, and its deposition mechanism was discussed. Results indicate that the pores in the plasma sprayed zirconia coating were stripe-like and near-sphere ～ like shaped, and no through holes were present in the coating. At the same time, small-sized cracks with random orientation were observed in the ceramic coating, and both the feedstock powders and plas-ma sprayed coating were composed of melt or half- melted nano-structured t-ZrO2.