Abstract:In order to improve the wear resistance and high-temperature oxidation resistance of superalloy GH202, the ultrafine-grain ceramic coating containing nano-size nickel particles was obtained by flow coat method on the surface of GH202. The interface microstructure between ceramic coating and superalloy GH202 substrate during vacuum diffusion was studied. It is shown that Al₂O₃ oxide layer and (Ti, N) compound exist in the alloy substrate close to interface. During long time diffusion, nano-size nickel powders gradually congregate and grow up, and the confluent interface appears, which shows that the nano-size nickel powders have the effect of restraining the coating from failure.

Key words: GH202 superalloy; nano-size nickel powder; ceramic coating; vacuum annealing; microstructure