Microstructure and thermo-physical properties of yttria stabilized zirconia coatings with CMAS deposits

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• 作者：Jing Wu^a ; Hong-bo Guo ; ^a ; ^{guo.hongbo@buaa.edu.cn"" rel=""nofollow} ; Yu-zhi Gao^a ; Sheng-kai Gong^a
• 关键词：Thermal barrier coatings (TBCs) ; Calcium– ; magnesium– ; alumina– ; silicate (CMAS) ; Microstructure ; Thermal diffusivity ; Microhardness
• 刊名：Journal of the European Ceramic Society
• 出版年：2011
• 出版时间：September 2011
• 年：2011
• 卷：31
• 期：10
• 页码：1881-1888
• 全文大小：912 K

文摘

Yttria stabilized zirconia (YSZ) thermal barrier coatings (TBCs) are used to protect hot-components in aero-engines from hot gases. In this paper, the microstructure and thermo-physical and mechanical properties of plasma sprayed YSZ coatings under the condition of calcium–magnesium–alumina–silicate (CMAS) deposits were investigated. Si and Ca in the CMAS rapidly penetrated the coating at 1250 °C and accelerated sintering of the coating. At the interface between the CMAS and YSZ coating, the YSZ coating was partially dissolved in the CMAS, inducing the phase transformation from tetragonal phase to monoclinic phase. Also, the porosity of the coating was reduced from 25 % to 5 % . As a result, the thermal diffusivity at 1200 °C increased from 0.3 mm²/s to 0.7 mm²/s, suggesting a significant degradation in the thermal barrier effect. Also, the coating showed a 40 % increase in the microhardness. The degradation mechanism of TBC induced by CMAS was discussed.