Silt Erosion Characteristics of a Cr_3C_2-NiCr Coating Fabricated by High Velocity Oxy-Fuel (HVOF) Thermal Spray

A Cr3C2-NiCr coating was prepared by high velocity oxy-fuel(HVOF)thermal spray on 1Cr18Ni9Ti stainless steel.Phases and microstructures of the coating were investigated by X-ray diffraction(XRD),optical microscopy(OM)and scanning election microscopy(SEM),respectively.The cavitation erosion resistance and silt erosion resistance of the coating were evaluated using a GB/T6383-2009 standard method in two experimental conditions(fresh water and water contained fine silt),compared with the coatings hydro machine material 1Cr18Ni9Ti stainless steel.The coating shows a layered structure and has a significantly higher microhardness(11.97 GPa)than that of the 1Cr18Ni9Ti stainless steel(2.1 GPa),which results in less mass losses both in cavitation erosion and silt erosion experiment.The HVOF coating has a predominant performance in the cavitation erosion and silt erosion resistance.The higher microhardness of the coating is the main cause which results in a less mass losses in the erosion experiments.And the mass loss usually happens at the edges of the pores.