Sputtering nanocrystalline coating was prepared on a nickel-based single-crystal superalloy N5. The oxidation behavior of the superalloy substrate and its nanocrystalline coating was investigated at 900-1100 degrees C. Results indicated that the nanocrystalline coating enhanced the oxidation and scale spallation resistance of the single-crystal superalloy. Elements interdiffusion has not occurred between the substrate and coating. Refractory element, Ta, inherently contained in N5, had a significant effect on the scale microstructure and oxidation behavior of both the single-crystal superalloy substrate and its sputtering nanocrystalline coating. (C) 2015 Elsevier B.V. All rights reserved.