Solid particle erosion-wear behaviour of Cr3C2-NiCr coating on Ni-based superalloy

There are very few attempts to explore the erosion-wear behaviour of the Cr3C2-NiCr coating deposited on the nickel-based superalloy employed to resist the solid particle erosion damages for flue gas turbine blade. This work focuses on the erosion mechanism of Cr3C2-NiCr coating under service conditions. A 75wt% Cr3C2-25wt% NiCr composite coating was prepared on Ni-based superalloy substrate material using high-velocity oxygen-fuel spraying technique. The coating surface has been characterized. The erosion behaviour and the effects of air pressure, impingement angle, erosion temperature and particle size on the erosion resistance of coating were studied. The results indicate that the volume erosion rate of the specimen increases gradually with the increase in air pressure. The volume wear rates of coating material increase with the decrease in coating thickness. Coating shows better erosion resistance at 90 degrees impact angle as compared to 30 degrees impact angle. The maximum volume erosion rate occurs at impact angle of 60 degrees. So, the combined mode of erosion mechanism (i.e. ductile and brittle) is observed in the Cr3C2-NiCr coating on nickel-based superalloy. The erosion-wear resistance of the materials can be improved at high temperatures. With the increase in the particle size, the volume erosion rates of the coating material increase. Erosion particle size and shape are the key factors that influence the erosion-wear behaviour.