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Effect of APS flash bond coatings and curvature on TBC performance on rod specimens.
- Source :
-
Surface & Coatings Technology . Nov2019, Vol. 378, pN.PAG-N.PAG. 1p. - Publication Year :
- 2019
-
Abstract
- The addition of an air plasma sprayed (APS) "flash" bond coating layer on top of a high velocity oxy-fuel (HVOF) bond coating significantly extended the lifetime of APS yttria stabilized zirconia (YSZ) thermal barrier coatings (TBC) on rod specimens of superalloy 247 tested using 100-h cycles in air+10%H 2 O at 1100 °C. The flash bond coatings of both NiCoCrAlY and NiCoCrAlYHfSi powder were compared to an HVOF-only and a vacuum plasma sprayed (VPS) NiCoCrAlYHfSi bond coating. The flash coatings appear to form a mixed oxide-metal zone, which likely inhibits crack formation and therefore extends lifetime compared to conventional bond coatings. The underlying dense HVOF layer appeared to act as a source of Al for this intermixed zone and prevented the oxide from penetrating deeper into the bond coating. Residual stress in the thermally-grown Al 2 O 3 scale was measured using photo-luminescence piezospectroscopy (PLPS) as a function of time for each coating variation, including a comparison of concave and convex surfaces on a specially designed rod. • The effect of an outer flash coat on a dense bond coat on rods was studied. • The flash bond coating significantly increased coating lifetime. • Porosity of the top-coat correlated with coating lifetime. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02578972
- Volume :
- 378
- Database :
- Academic Search Index
- Journal :
- Surface & Coatings Technology
- Publication Type :
- Academic Journal
- Accession number :
- 139924741
- Full Text :
- https://doi.org/10.1016/j.surfcoat.2019.124940