TY - GEN
T1 - Effect of APS flash bond coatings on furnace cycle lifetime of disks and rods
AU - Pint, Bruce A.
AU - Lance, Michael J.
AU - Allen Haynes, J.
AU - Gildersleeve, Edward J.
AU - Sampath, Sanjay
N1 - Publisher Copyright:
Copyright © 2019 ASME.
PY - 2019
Y1 - 2019
N2 - Air plasma sprayed (APS) flash coatings on high velocity oxygen fuel (HVOF) bond coatings are well known to extend the lifetime of thermal barrier coatings. Recent work compared flash coatings of NiCoCrAlY and NiCoCrAlYHfSi applied to both rods and disk substrates of alloy 247. For rod specimens, 100-h cycles were used at 1100°C in wet air. Both flash coatings significantly improved the lifetime compared to HVOF-only and VPS-only MCrAlY bond coatings with no statistical difference between the two flash coatings. For disk specimens tested in 1-h cycles at 1100°C in wet air, the NiCoCrAlY flash coating significantly outperformed an HVOF-only NiCoCrAlYHfSi bond coating and a NiCoCrAlYHfSi flash coating. The flash coatings formed a mixed oxide-metal zone that appeared to inhibit crack formation and extend lifetime. In addition to the flash coating increasing the bond coating roughness, the underlying HVOF layer acted as a source of Al for this intermixed zone and prevented the oxide from penetrating deeper into the bond coating. The lower Y+Hf level in the Y-only flash coating appeared to minimize oxidation in the flash layer, thereby increasing the benefit compared to a NiCoCrAlYHfSi flash coating.
AB - Air plasma sprayed (APS) flash coatings on high velocity oxygen fuel (HVOF) bond coatings are well known to extend the lifetime of thermal barrier coatings. Recent work compared flash coatings of NiCoCrAlY and NiCoCrAlYHfSi applied to both rods and disk substrates of alloy 247. For rod specimens, 100-h cycles were used at 1100°C in wet air. Both flash coatings significantly improved the lifetime compared to HVOF-only and VPS-only MCrAlY bond coatings with no statistical difference between the two flash coatings. For disk specimens tested in 1-h cycles at 1100°C in wet air, the NiCoCrAlY flash coating significantly outperformed an HVOF-only NiCoCrAlYHfSi bond coating and a NiCoCrAlYHfSi flash coating. The flash coatings formed a mixed oxide-metal zone that appeared to inhibit crack formation and extend lifetime. In addition to the flash coating increasing the bond coating roughness, the underlying HVOF layer acted as a source of Al for this intermixed zone and prevented the oxide from penetrating deeper into the bond coating. The lower Y+Hf level in the Y-only flash coating appeared to minimize oxidation in the flash layer, thereby increasing the benefit compared to a NiCoCrAlYHfSi flash coating.
UR - https://www.scopus.com/pages/publications/85075493975
U2 - 10.1115/GT2019-90501
DO - 10.1115/GT2019-90501
M3 - Conference contribution
AN - SCOPUS:85075493975
T3 - Proceedings of the ASME Turbo Expo
BT - Ceramics; Controls, Diagnostics, and Instrumentation; Education; Manufacturing Materials and Metallurgy
PB - American Society of Mechanical Engineers (ASME)
T2 - ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition, GT 2019
Y2 - 17 June 2019 through 21 June 2019
ER -