In addition to changing the surface roughness of the superalloy,the substrate surface treatment can also modify the microstructure of the surface,which affects the high-temperature oxidation behavior of the high-temperature protective coating.However,there are few reports about the effect of su-peralloy surface treatment on the oxidation behavior of nanocrystalline coatings.In this work,nanocrystal-line coatings were sputtered on the nickel-based single crystal superalloy after two different surface treat-ments of polishing and shot peening,and their cyclic oxidation behavior at 1100℃ was investigated.The phase composition and microstructure of nanocrystalline coatings were characterized by SEM,XRD,and EDS.The results indicated that the cyclic oxidation kinetics of both nanocrystalline coatings at 1100℃ were similar.A dense oxide film could be formed on the surface of nanocrystalline coatings,showing ex-cellent oxidation resistance.However,the microstructure evolution of the interface between the nanocrys-talline coating and shot-peened superalloy substrate differed from that between the nanocrystalline coat-ing and polished superalloy substrate.The sustained formation of the γ′ phase in the nanocrystalline coat-ing near the polished substrate/coating interface was observed during high-temperature oxidation.This phenomenon was not found at the nanocrystalline coating near the shot peened substrate/coating inter-face,while the continuous growth of the γ'phase was observed at the substrate.
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