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4684 |
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Wednesday, May 11, 2016, Room 3H + 3I + 3J 9:00 AM Power Generation I |
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Thermal stability of sub-micro structured YSZ coatings deposited by APS and SPS |
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Minglong Zhai* / Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Jiasheng Yang / Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Xinghua Zhong/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Huayu Zhao/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Chengguang Liu/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China Shunyan Tao/ Shanghai Institute of Ceramics, Chinese Academy of Sciences, China |
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The sub-micro structured YSZ coatings were deposited by atmospheric plasma spray (APS) and suspension plasma spay (SPS) using nano particle feedstocks, respectively. Free-standing YSZ coatings were isothermal treated in air from 1200 to 1600 for 24h and at 1550 for 20h to 100h. The phase composition, microstructure, hardness and Youngs modulus of the thermal aged coatings were examined. Results showed that the as-sprayed coating was a metastable tetragonal (t-ZrO2) phase. No evidence of any tetragonal-monoclinic phase transformation was detected in the coatings that is isothermally heat-treated for 24 h even though the heat treatment temperature is enhanced from 1200 to 1600 , but the phase transformation occurred after 1550/40h heat treatment. During the process of the isothermal treatment, the grain size of the coatings have grown evidently. Experimental results show that APS coating has a lower grain growth activation energy. Two kinds of as-sprayed coatings have the similar hardness (H) and Youngs modulus (E), the H and E values of the coatings improved significantly due to the isothermal treatment. Keywords: thermal barrier coatings; sub-micro structured coating; thermal stability |