摘要
采用等离子喷涂技术在高温合金上制备了热障涂层(粘接层为NiCoCrAlY,陶瓷层为ZrO2-8%Y2O3),利用扫描电镜(SEM)、拉曼光谱(RFS)等试验手段研究了热障涂层热震失效的过程及残余应力大小和分布状态。结果表明:150次热循环后,陶瓷层和热生长氧化物(TGO)生成裂纹,其中陶瓷层的裂纹已扩展至TGO;350次热循环后,出现贯通陶瓷层与金属过渡层的纵向裂纹,涂层局部出现剥离,剥离位置位于TGO与陶瓷层界面;拉曼光谱(RFS)分析结果显示TGO内应力水平分布不均,局部厚大区和凸凹处残余应力较大,是裂纹萌生、扩展的主要部位。
Thermal barrier coatings with NiCoCrAlY as bond coat and ZrO2 as ceramic coat was prepared by atmospheric plasma spraying method on GH99 superalloy surface.Thermal shock failure and residual stress of the coatings were studied by SEM and RFS.The results show that after 150 thermal cycles,micro-cracks in the thermally grown oxide（TGO） and cracks in the ceramic coat propagated to TGO were observed.After 350 thermal cycles,cracks propagate through the ceramic coat and bond coat,caused the top coat spalling-off partly from the interface of ceramic coat and TGO.RFS analysis indicates that the residual stress is not uniformly distributed in the coatings and is higher in the locations of larger block TGO,which leads to initiation and propagation of cracks along TGO.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2012年第4期116-120,共5页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金项目(60879018)
关键词
热障涂层
热循环
残余应力
热生长氧化物
thermal barrier coating（TBC）
thermal cycling
residual stress
thermally grown oxide（TGO）
