8YSZ热障涂层表面织构设计及其抗热震性能  

Surface Texture Design of 8YSZ Thermal Barrier Coating and Its Thermal Shock Resistance

作　　者：丁琦恒 胡丽娜 雷海军 张文超 黄延凯 DING Qiheng;HU Lina;LEI Haijun;ZHANG Wenchao;HUANG Yankai(School of Electrical Engineering,Xinjiang University,Urumqi 830017,China;Xinjiang Production and Construction Corps Development and Reform Commission,Urumqi 830002,China;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]新疆大学电气工程学院,乌鲁木齐830017 [2]新疆生产建设兵团发展和改革委员会,乌鲁木齐830002 [3]华中科技大学煤燃烧国家重点实验室,武汉430074

出　　处：《表面技术》2024年第15期224-233,共10页Surface Technology

基　　金：新疆维吾尔自治区重大科技专项(2022A01002-2);新疆维吾尔自治区重点研发任务专项(2022B03028-4);新疆维吾尔自治区天池百人计划(TCBR202106)。

摘　　要：目的研究不同表面织构形貌对8YSZ热障涂层的抗热震性能和失效机制的影响。方法采用微电火花在高温镍基合金基体表面设计加工4种形貌的表面织构,并利用大气等离子喷涂技术制备相同厚度的8YSZ热障涂层。采用水淬法进行热冲击试验,利用场发射扫描电子显微镜(FESEM)、X射线衍射仪(XRD)和能谱仪(EDS),分析不同表面织构的微观结构演变、断裂形态、残余应力和元素分布,结合能量释放率准则,揭示不同织构形貌对失效机制的影响。结果表面无织构的涂层的界面韧性较小,裂纹在边界和内部萌生,为氧气和腐蚀介质的扩散提供了通道,经热冲击后会发生大尺寸断裂,在16次水淬后出现大面积屈曲失效。凸织构顶部出现严重的应力集中现象,能量释放率较大,经18次水淬后脱黏失效。凹梯形织构界面韧性较大,内部残余应力较小,经30次水淬后织构两侧出现裂纹,平均抗热冲击次数为53,抗热冲击性能较好。结论涂层与镍基合金基体之间的热膨胀系数存在较大差异,涂层受到热冲击后在界面产生较大的热失配应力,促使裂纹萌生。表面织构能够有效提高涂层的界面韧性,由于凹梯形织构具有最佳的偏转角,界面增韧效果最好,且能够有效阻挡裂纹的扩展,使得断裂失效缓慢,热冲击寿命得到显著提高。可为热障涂层的表面织构设计提供理论指导。Thermal barrier coatings(TBCs)provide thermal protection for high-temperature components in aero-engines and steam turbines.But thermal barrier coatings are prone to failure when exposed to cyclic thermal shock loads.To meet the increasing demand for device performance,optimizing surface texture has emerged as a promising strategy to extend the lifetime of TBCs.In this investigation,four surface textures(convex sine,concave semicircle,concave cosine,concave trapezoid)were processed on the substrate surface of nickel-based superalloys,and 8YSZ ceramic coating samples with equal thickness were prepared by atmospheric plasma spraying for the subsequent cyclic thermal shock test.A range of analytical techniques,including field emission scanning electron microscopy(FESEM),X-ray diffraction(XRD)and energy disperse spectroscopy(EDS),were employed in this paper to scrutinize microstructural evolution,fracture morphologies,residual stress distribution during thermal shock as well as the elemental composition distribution related to the diffusion of oxygen and corrosive medium.Combined with the energy release rate criterion,the influence of the morphology of different surface textures on the failure mechanism was revealed.The findings highlighted the critical role of surface texture in enhancing the performance of TBCs.TBC samples without these textures exhibited lower interfacial toughness in tests,making them susceptible to cracks and voids at the boundaries and within the coating itself.This higher propensity to failure provided avenues for oxygen and corrosive permeation,ultimately leading to catastrophic fracture during water quenching.Furthermore,the study showed that convex textures,characterized by pronounced stress concentrations at their vertices,exhibited significantly elevated energy release rates.Consequently,this structure exhibited debonding failure after only 18 water quenching cycles.In stark contrast,the concave trapezoidal texture exhibited superior interfacial toughness,minimal internal residual stress,

关 键 词：热障涂层 表面织构 热冲击 微观结构 失效机制 抗热震性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]