Thermal cycle lifetimes of two thermal barrier coating (TBC) systems with the same plasma sprayed yttria-stabilized- zirconia (YSZ) topcoat but different low pressure plasma sprayed (LPPS) bond coats, conventional and cryomilled NiCrAlY feedstock powder, were studied. Thermal cycling tests consisted of 50 min at 1121C followed by 10 min air-cooling to room temperature. The coating produced with the cryomilled powder showed a 300% increase in lifetime when compared to the conventional one. Both TBCs failed as a result of delamination and spallation of the ceramic top coats. Several factors like thermally grown oxide (TGO) thickness, TGO composition, CTE mismatch, creep resistance of the NiCrAlY bond coat, and others that affected the thermal cycling life of the system, were analyzed in this work. Abstract only; no full-text paper available.

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