• Journal of Inorganic Materials
  • Vol. 36, Issue 10, 1059 (2021)
FAN Wenqi1, SONG Xuemei2, HUANG Yiling2, and CHANG Chengkang1、*
Author Affiliations
  • 11. School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418, China
  • 22. Inorganic Materials Analysis and Testing Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
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    Abstract

    To study the microstructure changes and phase transitions of different depth areas in the YSZ coating caused by corrosion of the calcium magnesium aluminum silicate (CMAS) at high temperature, scanning electron microscope (SEM) and an X-ray diffractometer (XRD), energy-dispersive X-ray spectroscope (EDS) and electron backscatter diffraction (EBSD) were used to characterize and analyze the YSZ coating before and after corrosion. The results show that YSZ coating after high-temperature CMAS corrosion exhibits spalling, dense, light dense and obvious layered structure from top to bottom. The melting/recrystallization phenomenon occurs on the top of the YSZ coating, which causes a phase transition from initial t-ZrO2 particles to m-ZrO2 particles and the degree of the phase transition decreasing from top to bottom. It is also found that the CMAS-induced phase transition mainly occurs at the grain boundaries since the molten CMAS is easier to penetrate and erode along the grain boundaries of the coating.

    燃气轮机涡轮叶片通过涂覆热障涂层(TBCs), 不仅可以降低基板表面的温度[1], 而且可以保护基体免受氧化和腐蚀, 从而延长燃气轮机的使用寿命[2]。常用的TBCs主要由7wt%的氧化钇部分稳定氧化锆(YSZ)组成[3]。大气环境沉积物钙镁铝硅酸盐(CMAS)对涂层的高温侵蚀[4]以及YSZ陶瓷层的相转变[5]是导致热障涂层劣化和失效的主要原因。在服役过程中, 当发动机运行温度高于CMAS的熔点(1200 ℃以上)时, 沉积在陶瓷涂层表面的CMAS由固态转变为液态, 熔融的CMAS会沿着涂层的孔隙、微裂纹和晶界渗入到涂层内部并沉积, 导致涂层的应变容限降低。在热循环过程中, CMAS和TBCs之间由于热膨胀不匹配会在涂层内部产生较大的应力, 这种应力不断积累会诱发裂纹, 裂纹扩展最终导致TBCs失效[6,7,8,9,10]

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    Wenqi FAN, Xuemei SONG, Yiling HUANG, Chengkang CHANG. Structure Change and Phase Transition Distribution of YSZ Coating Caused by CMAS Corrosion[J]. Journal of Inorganic Materials, 2021, 36(10): 1059
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    Category: RESEARCH ARTICLE
    Received: Jan. 8, 2021
    Accepted: --
    Published Online: Nov. 26, 2021
    The Author Email: CHANG Chengkang (ckchang@sit.edu.cn)