Influence of Heat Treatment on the Bond Coat Cyclic Oxidation Behaviour in an Air-plasma-sprayed Thermal Barrier Coating System
来源期刊：材料热处理学报2004年第5期
论文作者：P.C. Patnaik B.R. Marple W.R. Chen X. Wu
关键词：TBC; CoNiCrAlY; TGO; low-pressure oxidation treatment; cyclic oxidation;
摘 要：It is generally believed that a thermally grown oxide (TGO) layer of alumina provides enhanced protection to the metallic bond coat in thermal barrier coating (TBC) systems at elevated temperatures. However, in an air-plasma-sprayed (APS) TBC system with Co-32Ni-21Cr-8A1-0.5Y (wt%) bond coat, the TGO layer formed upon thermal exposure in air was predominantly chromia and spinels, which would not effectively protect the bond coat at above 1000℃. In addition,mixed oxides of chromia, spinel and nickel oxide formed heterogeneously between the ceramic coating and CoNiCrAlY bond coat, which would promote crack initiation and lead to premature TBC failure. A heat treatment in a low-pressure condition was applied to the as-sprayed TBC system, with the aim to produce an alumina layer as well as reduce the amount of detrimental oxides. The influence of this low-pressure oxidation treatment (LPOT) on the bond coat cyclic oxidation behaviour of the TBC system was also investigated.
P.C. Patnaik1，B.R. Marple2，W.R. Chen1，X. Wu1
(1.Structures, Materials and Propulsion Laboratory, Institute for Aerospace Research, National Research Council Canada, Ottawa, Ontario, Canada, KIA OR6;
2.Industrial Materials Institute, National Research Council Canada, Boucherville, Quebec, Canada, J4B 6Y4)
摘要:It is generally believed that a thermally grown oxide (TGO) layer of alumina provides enhanced protection to the metallic bond coat in thermal barrier coating (TBC) systems at elevated temperatures. However, in an air-plasma-sprayed (APS) TBC system with Co-32Ni-21Cr-8A1-0.5Y (wt%) bond coat, the TGO layer formed upon thermal exposure in air was predominantly chromia and spinels, which would not effectively protect the bond coat at above 1000℃. In addition,mixed oxides of chromia, spinel and nickel oxide formed heterogeneously between the ceramic coating and CoNiCrAlY bond coat, which would promote crack initiation and lead to premature TBC failure. A heat treatment in a low-pressure condition was applied to the as-sprayed TBC system, with the aim to produce an alumina layer as well as reduce the amount of detrimental oxides. The influence of this low-pressure oxidation treatment (LPOT) on the bond coat cyclic oxidation behaviour of the TBC system was also investigated.
关键词:TBC; CoNiCrAlY; TGO; low-pressure oxidation treatment; cyclic oxidation;
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