悬浮液等离子体喷涂厚YSZ热障涂层结构与性能研究  

Investigation on Microstructure and Properties of Suspension Plasma Sprayed Thick YSZ Thermal Barrier Coatings

作　　者：杨加胜[1] 钟兴华[1] 陶顺衍[1] 邵芳[1] 程泽飞 赵华玉[1] 庄寅[1] 倪金星 YANG Jia-sheng;ZHONG Xing-hua;TAO Shun-yan;SHAO Fang;CHENG Ze-fei;ZHAO Hua-yu;ZHUANG Yin;NI Jin-xing(The Key Laboratory of Inorganic Coating Materials CAS,Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai 201899 China)

机构地区：[1]中国科学院上海硅酸盐研究所中国科学院特种无机涂层重点实验室

出　　处：《湘潭大学学报（自然科学版）》2019年第6期61-68,共8页Journal of Xiangtan University(Natural Science Edition)

基　　金：国家科技重大专项项目(2017-VI-0010-0082);上海市科委项目(18511108702)

摘　　要：采用悬浮液等离子体喷涂(SPS)工艺在以GH3128高温合金为基底,CoNiCrAlY为黏结层的表面上制备氧化钇部分稳定的氧化锆(YSZ)厚热障涂层(TTBCs),研究单片层的形貌特征及单片层之间的堆叠行为对涂层微结构的影响.对无支撑的YSZ涂层进行了1200~1600℃保温24 h和1550℃保温20~100 h的高温时效处理,分析涂层的物相组成和晶粒尺寸等的变化;对涂层试样进行了高温燃气焰流循环热考核,并对其失效机理进行了探讨.结果表明,SPS单片层由四方相晶粒组成.涂层经1550℃高温热处理40 h发生四方相(t)向单斜相(m)转变,且m相的含量随热处理时间的延长而增加,但对于24 h高温处理样品,即便将热处理温度提升到1600℃,也未见t→m相变.SPS涂层经热考核前后应力演变是其失效根源,通过相邻柱状晶的脱落可有效地释放陶瓷层中的应力集中,最终与界面附近陶瓷层微裂纹相互连接而导致涂层剥落.In the present work,YSZ thick thermal barrier coatings(TTBCs)were deposited onto the surface of GH3128 superalloy with CoNiCrAlY bondcoat via suspension plasma spraying(SPS)technology.The effect of morphological characteristics of splat and stacking behavior between splats on the microstructure of SPS coatings were investigated.Free standing TTBCs were isothermally heat treated from 1200℃to 1600℃for 20 h to 100 h.Thermal stability behavior of TBCs such as phase composition and grain size for thermal aged coatings were examined.The thermal cycling test of the coatings was carried out and the failure mechanism was discussed.The result shows that each of the observed splats contained one crystalized grain with tetragonal structure.SPS TBCs transform from the initial single phase structure of non-transformable tetragonal(t’)phase to monoclinic(m)phases after 1550℃/40 h thermal exposure and the m phase increased gradually with prolonged thermal aging time,but with no tetragonal-monoclinic transformation for shorter thermal aging time of 24 h even when the thermal aging temperature is improved to 1600℃.The failure of SPS coatings under thermal cycling test was mainly due to the evolution of the residual stresses generated at the undulating topcoat/TGO/bondcoat interface.Local spot spallations could effectively release the stresses in the topcoat.Finally,the delamination would occur when the linking cracks size in the topcoat near the topcoat/TGO/bondcoat interface reached to a critical level.

关 键 词：悬浮液等离子体喷涂 厚热障涂层 单片层 高温稳定性 热循环测试 

分 类 号：TQ174[化学工程—陶瓷工业]