Deposition and Texture of Columnar Thermal Barrier Coatings
CHENG Zefei1,2, YANG Jiasheng1,2, SHAO Fang1,2, ZHAO Huayu1,2, ZHONG Xinghua1,2, ZHUANG Yin1,2, NI Jinxing1,2, TAO Shunyan1,2
1. Key Laboratory of Inorganic Coating Materials, 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
As a novel technique, plasma spray–physical vapor deposition (PS–PVD) process combines advantages of high deposition rates and cost-efficiency of plasma spraying and columnar structure of electron beam-physical vapor deposition (EB–PVD), so that PS–PVD has received considerable attention to manufacture thermal barrier coatings (TBCs) for some advanced turbines. In this paper, yttria stabilized zirconia (YSZ) coatings were fabricated by PS–PVD. Field emission scanning electron microscopy (FE–SEM) and electron backscatter diffraction (EBSD) were used to observe and analyze the microstructure and crystallographic feature of the coating. The result shows that the microstructure of as-sprayed YSZ coating is columnar structure crystals. During the process of deposition, at a certain spraying distance, the transition zone from the center to the edge of the spraying spot, the end surface of columns is transformed from a quadrangular pyramid structure to a cauliflower-like structure, and the mono-column exhibits a certain preferred orientation, but other columns have different orientations, and the ceramic does not exhibit a distinct preferred orientation on the whole.