Influence of post-spraying heat treatments on the oxidation and cracking behaviour of thermal-sprayed thermal barrier coatings

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Proceedings title12th International Conference on Fracture 2009 (ICF-12)
Conference12th International Conference on Fracture (ICF 2009): Ottawa, Ontario, Canada, July 12-17, 2009
Pages# of pages: 10
Subjectbarrier coating; post-spraying heat treatment; thermal cycling; crack propagation
AbstractThe durability of a thermal barrier coating (TBC) system is dominated by fracture near the interface between the ceramic topcoat and metallic bond coat, where a layer of thermally grown oxide (TGO) would form during service exposure. Even though the formation of a continuous alumina scale would help to protect the bond coat from further oxidation, the spontaneous formation of other mixed oxides such as spinel and nickel oxide are believed to be detrimental to TBC durability. The formation of such detrimental oxides may promote crack nucleation and accelerate crack propagation during thermal exposure, leading to premature TBC failure. The present study shows that post-spraying heat treatment in low-pressure oxygen environments can promote the formation of a thin alumina scale that suppresses the spontaneous formation of detrimental oxides during subsequent thermal exposure. This results in an improved oxidation resistance of the bond coat and, hence, it slows down crack propagation in the thermal-spray TBC systems. The relationship between the oxide scale growth and crack propagation is also established through extensive metallurgical examination, which serves as the basis for a TBC life prediction model.
Publication date
PublisherCurran Associates, Inc.
AffiliationNRC Institute for Aerospace Research; NRC Industrial Materials Institute; National Research Council Canada
Peer reviewedNo
NRC number52406
NPARC number18422700
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Record identifierbb9e6f9b-727d-4356-bfc1-1e89102f9fe3
Record created2011-08-23
Record modified2016-05-09
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