Effect of Substrate Curvature on Residual Stresses and Failure Modes of an Air Plasma Sprayed Thermal Barrier Coating System

D Liu, Maud Seraffon, Peter E J Flewitt, Nigel Simms J, John Nicolls R, David Rickerby S

Research output: Contribution to journalArticle (Academic Journal)peer-review

45 Citations (Scopus)

Abstract

A set of aerofoil shaped air plasma sprayed thermal barrier coated (APS-TBC) specimens
were adopted in this paper to investigate the stress distributions in the ceramic top coat (TC)
and the thermally grown oxide (TGO), the mechanism of local crack generation and
propagation at the TC / BC (bond coat) interface. The failure mode of the TBC system, the
distribution of asperities at TC / BC interface, thickness of the TC and BC, and the TC
microstructure were found to be influenced by substrate curvature. Residual stress was
therefore measured across the thickness of the TC, along the undulating TGO and mapped at
locations of asperities where failure tended to occur to interpret the initiation of local failure.
The role of the TGO was investigated via its chemical bonding with the TC and the
decohesion occurring at the TGO / BC interface. The crack propagation at the interface has
been discussed with respect to the macro-failure of the TBC system.
Original languageEnglish
JournalJournal of the European Ceramic Society
DOIs
Publication statusAccepted/In press - 2013

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