水氧腐蚀对Yb_(2)Si_(2)O_(7)涂层裂纹扩展的影响  

Effect of Water Oxygen Corrosion on Crack Propagation of Yb_(2)Si_(2)O_(7)Coating

作　　者：丁坤英 刘子剑 王梦潇 张涛 王者 DING Kunying;LIU Zijian;WANG Mengxiao;ZHANG Tao;WANG Zhe(Tianjin Key Laboratory for Airworthiness and Maintenance of Civil Aircraft,Civil Aviation University of China,Tianjin 300300,China)

机构地区：[1]中国民航大学,天津市民用航空器适航与维修重点实验室,天津300300

出　　处：《硅酸盐学报》2024年第9期2981-2994,共14页Journal of The Chinese Ceramic Society

基　　金：国家重点研发计划资助(2023YFB4302400)。

摘　　要：双硅酸镱(Yb_(2)Si_(2)O_(7),YbDS)与碳化硅复合材料(CMC)基体具有良好的热匹配能力,是目前环境障涂层(EBCs)中常用材料。然而,在高温水氧腐蚀环境中YbDS向单硅酸镱(Yb_(2)SiO_(5),YbMS)的转变导致涂层发生开裂和分层。为了分析水氧腐蚀对相转变和由此引发的EBC内应力的影响,本工作从实验观察和仿真计算,采用大气等离子喷涂制备Si+YbDS涂层,通过循环热载荷水氧腐蚀实验分析YbDS涂层的腐蚀产物和腐蚀速率,计算YbDS腐蚀过程中导致EBC内应力的再分布特征,分析由此引发的裂纹扩展。结果表明,完成沉积后的YbDS面层受残余压应力作用,而在蒸汽循环腐蚀后的YbDS涂层中出现了拉应力,较大的应力导致EBC过早开裂。YbDS成分挥发导致的孔隙增加对腐蚀区的应力影响较大,孔隙也提高了Ⅰ型裂纹的扩展速率。Introduction The aimed environmental barrier coatings(EBCs)need to meet the characteristics of low oxygen permeability,match thermal expansion coefficient,and keep phase stability under service conditions,which usually need to be designed as a multi-layer structures to avoid premature failure of gas turbine engines during operation.Yb_(2)Si_(2)O_(7)(YbDS)is considered the most promising candidate due to its excellent resistance to water vapor corrosion and damage tolerance,a similar coefficient of thermal expansion(4.1×10^(-6)/K)to that of the matrix material(SiC,4.7×10^(-6)/K),and does not generate high thermal cycling stress in EBCs systems.However,when YbDS was exposed to an environment containing with high-temperature water vapor,corrosion transformation may occur,which would reduce the durability of EBCs.To analyze the corrosion process,stress characteristics,and crack propagation laws of YbDS under the coupling effect of water-oxygen corrosion and thermal cycling,the compositional and structural changes of YbDS under high-temperature water-oxygen action were determined through experiments,also the influence of water-oxygen corrosion on the stress evolution of the coating was explored using finite element software Abaqus.The extended Finite Element Method(XFEM)was used to simulate the propagation path of cracks in YbDS,and the accelerating effect of water-oxygen corrosion on crack propagation was diScussed finally.Methods The Si powder was used for bond coat deposition,and Yb_(2)Si_(2)O_(7)powder was used for top coat deposition.Powders used in this experiment were designed with a particle size distribution suitable for thermal spray applications.Both the bond coat and top coat were deposited onto theφ25.4 mm×3 mm SiC substrate using the Praxair 3710 air plasma spraying system.Thermal cycling tests of the EBC system was conducted in an aluminum oxide tube furnace at 1325℃,The ratio of water vapor to oxygen was controlled to 9:1 by a gas-liquid mixing device,samples were took out and cooled to room temp

关 键 词：双硅酸镱 环境障涂层 水氧腐蚀 有限元分析 应力分析 

分 类 号：V254.2[一般工业技术—材料科学与工程]