| Abstract: |
In this study, Al2O3-Y2O3 composite coatings have been manufactured by plasma spraying using in-house synthesized nanocomposite feedstock powders. Unlike a typical splatted lamellae characteristic in thermal sprayed coatings, the plasma sprayed Al2O3-Y2O3 coatings consisted of almost featureless and amorphous microstructure, with no formation of a discrete splat boundary. Subsequent heat treatment above 1000oC led to the precipitation of various crystalline phases, the sizes of which were controlled by heat treatment temperatures. The crystallization of Al2O3-Y2O3 nanocomposites resulted in a significant increase in hardness up to ~2400Hv, compared to 700-800Hv for the amorphous coating. Corrosion/erosion resistance of the coatings was evaluated using an inductively couple plasma with F-containing gases. The degree of crystallinity and the size of constituent phases significantly affect the plasma-induced damage behavior of the Al2O3-Y2O3 composite coatings.
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