Bond coat engineering influence on the evolution of the microstructure, bond strength, and failure of TBCs subjected to thermal cycling

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DOIResolve DOI: http://doi.org/10.1007/s11666-014-0181-3
AuthorSearch for: ; Search for: ; Search for:
TypeArticle
Proceedings titleJournal of Thermal Spray Technology
Conference2014 International Thermal Spray Conference (ITSC), May 21-23, 2014, Barcelona, Spain
ISSN1059-9630
1544-1016
Pages18; # of pages: 8
Subjectbond coat; bond strength; CoNiCrAlY; furnace cycle testing (FCT); TBC
AbstractDifferent types of thermal spray systems, including HVOF (JP5000 and DJ2600-hybrid), APS (F4-MB and Axial III), and LPPS (Oerlikon Metco system) were employed to spray CoNiCrAlY bond coats (BCs) onto Inconel 625 substrates. The chemical composition of the BC powder was the same in all cases; however, the particle size distribution of the powder employed with each torch was that specifically recommended for the torch. For optimization purposes, these BCs were screened based on initial evaluations of roughness, porosity, residual stress, relative oxidation, and isothermal TGO growth. A single type of standard YSZ top coat was deposited via APS (F4MB) on all the optimized BCs. The TBCs were thermally cycled by employing a furnace cycle test (FCT) (1080 °C-1 h—followed by forced air cooling). Samples were submitted to 10, 100, 400, and 1400 cycles as well as being cycled to failure. The behavior of the microstructures, bond strength values (ASTM 633), and the TGO evolution of these TBCs, were investigated for the as-sprayed and thermally cycled samples. During FCT, the TBCs found to be both the best and poorest performing and had their BCs deposited via HVOF. The results showed that engineering low-oxidized BCs does not necessarily lead to an optimal TBC performance. Moreover, the bond strength values decrease significantly only when the TBC is about to fail (top coat spall off) and the as-sprayed bond strength values cannot be used as an indicator of TBC performance.
Publication date
LanguageEnglish
AffiliationAutomotive and Surface Transportation; National Research Council Canada
Peer reviewedYes
NRC numberNRC-AST-147063
NPARC number21272380
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Record identifier5cadbf6b-3a65-4887-be1c-41624d203123
Record created2014-11-25
Record modified2016-05-09
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