Influence of NiCrAlY coatings by arc ion plating on hot corrosion behaviour of single crystal nickel-based superalloy

Ni28Cr11Al0.5Y coatings were deposited on a single crystal Ni-base superalloy substrate by arc ion plating.The corrosion behaviors of the superalloy and Ni28Cr11Al0.5Y coatings in molten 75%Na2SO4+25% K2SO4(mass fraction) at 900 ℃ were studied.The results indicate that the superalloy suffer catastrophic hot corrosion,and serious internal oxidation and internal sulfidation occur in a single crystal Ni-base superalloy.The regions near the layer of the surface are identified as the internal oxidizing zones,and the matrix region far from the layer of the surface is identified as the internal sulfidation zone.During the hot corrosion of Ni28Cr11Al0.5Y,the continuous Al2O3oxidation film forms,and with the hot corrosion time increasing,the oxidation film becomes thick and has better hot corrosion resistance property.