Microstructure and Anti-Abrasion Properties of HVOF Sprayed Cr₃C₂-25NiCr Coating and WC-12Co Coating

Cr₃C₂-25NiCr coating and WC-12Co coating were prepared by high velocity oxygen fuel (HVOF) spraying technology on the surface of 0Cr13Ni5Mo stainless steel used for hydraulic turbines. The microstructure, micro-hardness, porosity, impact toughness and erosion corrosion resistance of the two coatings were analyzed in comparison by metallographic microscope, micro hardness tester, impact toughness tester, friction and wear tester, scanning electron microscope. The results show that the porosity of the Cr₃C₂-25NiCr coating was 0.97% and the average micro-hardness was 1 113 HV, while the porosity of the WC-12Co coating was 0.56% and the average micro-hardness was 1 241 HV. The WC-12Co coating had better impact toughness and erosion corrosion resistance compared with those of the Cr₃C₂-25NiCr coating. The failure of the coatings was mainly the result of combined erosion and corrosion of sand, water and bubbles.