DZ466合金热障涂层CoCrAlY黏结层1050℃氧化行为  

Oxidation Behavior of CoCrAlY Bond Coating for Thermal Barrier Coating on DZ466 Super Alloy at 1050℃

作　　者：任维鹏[1] 李青[1] 肖程波[1] 宋尽霞[1] 何利民[2] 黄光宏[2] 曹春晓[1] 

机构地区：[1]北京航空材料研究院先进高温结构材料重点实验室,北京100095 [2]北京航空材料研究院金属腐蚀与防护研究室,北京100095

出　　处：《材料工程》2014年第6期74-78,83,共6页Journal of Materials Engineering

基　　金：国家863计划资助项目(2012AA03A511);工信部科技专项资助项目(2012ZX04007-021-03)

摘　　要：采用电子束物理气相沉积(EB-PVD)法在一种新型定向合金DZ466试样上沉积CoCrAlY黏结层和Y2O3部分稳定的ZrO2(YSZ)陶瓷层,对试样进行1050℃循环氧化实验并研究其氧化行为。采用X射线衍射仪、扫描电镜以及电子探针对涂层进行显微组织分析。结果表明:在1050℃氧化1500h(热循环31次)后,热障涂层未出现脱落现象。沉积态CoCrAlY黏结层主要由β-CoAl相和γ-Co固溶体相组成;1050℃氧化后,在黏结层与陶瓷层界面生成热生长氧化物(TGO)层,黏结层逐渐发生退化,β-CoAl相逐渐转化为γ-CoNi固溶体;氧化1200h后,TGO/黏结层界面出现由活性元素效应导致的氧化物栓;TGO层皱曲行为导致TGO/陶瓷层界面出现微裂纹,并且该微裂纹沿界面横向扩展。TGO的厚度增长模式符合分段抛物线规律,初期氧化速率常数约为6.1×10-14cm2/s,氧化400h后,氧化速率常数减小,为3.5×10-14cm2/s。CoCrAlY bond coating and Y2O3 partially stabilized ZrO2 ceramic coating were deposited by electron beam physical vapor deposition（EB-PVD）,and the cyclic oxidation behavior of the samples were measured at 1050℃.X-ray diffraction,scanning electron microscopy and electron probe microanalysis were employed to examine the microstructure.The results show that the thermal barrier coating（TBC）remains intact after exposure at 1050℃ for 1500h（31cycles）.As-deposited CoCrAlY bond coating consists ofβ-CoAl phase andγ-Co solid solution,thermally grown oxide（TGO）appears at the interface of bond coating and ceramic coating during exposure at 1050℃ and meanwhile degradation of bond coating occurs,β-CoAl phase gradually transforms intoγ-Co solid solution.Oxide pegs form at the TGO/bong coating interface due to reactive elements effect after oxidation for 1200h.Rumpling of TGO induces micro-cracks at interface of TGO/ceramic coating,and the micro-cracks propagate along the interface.Thickness growth mode of TGO follows staged parabolic law,the initial oxidation rate constant is about 6.1×10^-14cm^2/s,after exposure for 400h,the oxidation rate constant decreases to 3.5×10^-14cm2/s.

关 键 词：DZ466合金 CoCrAlY 黏结层 热生长氧化物 氧化速率常数 

分 类 号：TG174.451[金属学及工艺—金属表面处理]