Comparative study of oxidation and interdiffusion behavior of AIP NiCrAlY and sputtered nanocrystalline coatings on a nickel-based single-crystal superalloy

The oxidation and interdiffusin behavior of NiCrAlY and sputtered nanocrystalline coatings on a single-crystal superalloy were studied. Results indicated that the superalloy substrate already possessed a high oxidation resistance. However the spallation resistance of oxide scale was very low. NiCrAlY coating enhanced the spallation resistance to some extent of the superalloy substrate at the expense of elevating oxidation rate and occurrence of severe interdiffusion. Sputtered nanocrystalline coating enhanced substantially the spallation resistance of the superalloy substrate meanwhile avoided elements interdiffusion. Its oxidation rate was lower than the superalloy substrate at 1000 °C but a little higher at 1100 °C.