Critical Thinking in Thermal Durability of Yttria Partially Stabilized Zirconia Ceramic Coating
DU Boyu1,2, YANG Jiasheng1, TAO Shiqian1,2,3, ZHAO Huayu1, ZHONG Xinghua1, ZHUANG Yin1, SHENG Jing1, NI Jinxing1, SHAO Fang1, TAO Shunyan1,2
1. The Key Laboratory of Inorganic Coating Materials CAS, Shanghai Institute of Ceramics,
Chinese Academy of Sciences, Shanghai 201899, China;
2. Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China;
3. Laboratory of Micro-Nano Optoelectronic Materials and Devices, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
Yttria partially stabilized zirconia (YSZ), a component of thermal barrier coatings, is widely used in complex high temperature conditions. The excellent thermal durability is attributed to non-transformable tetragonal phase (t′). Currently, it is uncertain for the maximum working temperature of t′ phase, and the mainstream view is still around 1200 ℃. Based on this, using atmospheric plasma spray (APS) process, YSZ coatings were fabricated followed by various thermal aging treatment. Evolution of microstructure, phase composition, sintering shrinkage and fracture toughness were investigated. The results show that the coating tested in 24 h@1400 ℃ still maintains m phase free even after 7–year room temperature storage; samples heat treated at 300 h@1400 ℃ and 300 h@1600 ℃ no broken, with m phase volume content of 3.55% and 35.41%, respectively. The average linear shrinkage of 300 h@1600 ℃ heat treated coatings is 0.4%. Grain growth and pore healing occurred during thermal aging treatment, bringing the increase of the bending strength and fracture toughness of coatings. Therefore, APS YSZ coatings can be used at 1400 ℃ for long time (~300 h) service.
2023, 
