High-temperature properties of plasma-sprayed coatings of YSZ/NiCrAlY on Inconel substrate

Abstract

Eleven-layered functionally gradient thermal barrier coatings (TBCs) were sprayed on Inconel substrate by varying the feeding ratio of YSZ/NiCrAlY in 0.1 intervals in the range of 0-1 linearly as well as nonlinearly (concave and convex type). The performance of the coatings was evaluated in terms of high-temperature fatigue, oxidation resistance, and bond strength. The fatigue behavior and the oxidation resistance were governed by the oxidation of Al in the NiCrAlY bond coating. The bond strength was determined by continuity of the composition and the microstructure between the layers. The linearly sprayed TBCs showed the highest endurance at high-temperatures among the coatings investigated, indicating that the linear feeding technique can be used for the high-temperature applications. (C) 2002 Elsevier Science B.V. All rights reserved.