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Effect of water vapor on the spallation of thermal barrier coating systems during laboratory cyclic oxidation testing

Déneux, V. and Cadoret, Y. and Hervier, S. and Monceau, Daniel Effect of water vapor on the spallation of thermal barrier coating systems during laboratory cyclic oxidation testing. (2009) Oxidation of Metals, vol. 73 (n° 1-2). pp. 83-93. ISSN 1573-4889

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Official URL: http://dx.doi.org/10.1007/s11085-009-9170-1

Abstract

The effect of water and water vapor on the lifetime of Ni-based superalloy samples coated with a typical thermal barrier coating system—b-(Ni,Pt)Al bond coat and yttria stabilized zirconia (YSZ) top coat deposited by electron beam physical vapor deposition (EB-PVD) was studied. Samples were thermally cycled to 1,150 C and subjected to a water-drop test in order to elucidate the effect of water vapor on thermal barrier coating (TBC) spallation. It was shown that the addition of water promotes spallation of TBC samples after a given number of cycles at 1,150 C. This threshold was found to be equal to 170 cycles for the present system. Systems based on b-NiAl bond coat or on Pt-rich c/c0 bond coat were also sensitive to the water-drop test. Moreover, it was shown that water vapor in ambient air after minutes or hours at room temperature, promotes also TBC spallation once the critical number of cycles has been reached. This desktop spalling (DTS) can be prevented by locking up the cycled samples in a dry atmosphere box. These results for TBC systems confirm and document Smialek’s theory about DTS and moisture induced delayed spalling (MIDS) being the same phenomenon. Finally, the mechanisms implying hydrogen embrittlement or surface tension modifications are discussed.

Item Type:Article
Additional Information:Thanks to Springer Netherlands editor. The definitive version is available at http://www.springerlink.com/ The original PDF of the article can be found at Oxidation of Metals website : http://www.springerlink.com/content/2447l847565r12v1/
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS
Other partners > SAFRAN (FRANCE)
Laboratory name:
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Deposited By:Nihad Lahdifi

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