Corrosion, Erosion Corrosion and Wear Behaviors of Ni-P-₂O₃ Coating

The corrosion, erosion-corrosion and wear behaviors of Ni-P-Al2O3 coating on the surfaces of steel 65Mn and W6Mo5Cr4V2 were systematicly studied by weight loss method. The surface morphology and chemical composition were also analyzed by means of SEM and EDS respectively. The results show that the corrosion and erosion-corrosion resistances of Ni-P-Al2O3 coating more excellent than those of 316L stainless steel, and increased with the increase of medium temperature and decreased when the steel was heat treated at 400 ℃. The corrosion rates of the Ni-P-Al2O3 coating in different solution under the same test condition were in the order of Na2S < HCl < H2SO4. The main corrosion characteristic of the Ni-P-Al2O3 coating was uniform corrosion in 20%Na2S and 20%H2SO4 solutions, localized corrosion in 20%HCl solution. The were resistance of Ni-P-Al2O3 coating is poorer than that of high-speed steel in the air.