Microstructure and Wear Properties of High Velocity Oxygen Fuel Sprayed Cr₃C₂-NiCr Coating

The Cr₃C₂-NiCr coating was prepared on H13 steel substrate by high velocity oxygen fuel spraying technique. The microstructure,phase composition and friction and wear properties of the coating were studied, and the wear mechanism was discussed. The results show that the Cr₃C₂-NiCr coating with a thickness of about 340 μm was closely combined with the H13 steel substrate. The coating was composed of Cr₃C₂ hard phase, NiCr bonding phase and a small amount of Cr₇C₃, and the structure was dense with a porosity of 0.63%. The stable friction coefficients of the Cr₃C₂-NiCr coating and H13 steel were 0.90 and 0.75, respectively, and the wear track depth and wear rate of the coating were only half that of H13 steel, showing that the coating had relatively good wear resistance. The main wear mechanism of the Cr₃C₂-NiCr coating was abrasive wear and fatigue wear.