Corrosion Resistance of Thermal Sprayed Ceramic Coatings in NaCl Solution

WC-Cr₃C₂-Ni coating and Al₂O₃-40TiO₂ coating were prepared by high-velocity oxygen-fuel spraying and plasma spraying, respectively. The corrosion resistance of the two thermal sprayed ceramic coatings in 3.5wt%NaCl solution was studied.The results show that WC-Cr₃C₂-Ni coating has passivation phenomenon in 3.5wt%NaCl solution and has good pitting resistance. Compared with Al₂O₃-40TiO₂ coating, the corrosion potential of WC-Cr₃C₂-Ni coating is higher and the corrosion current density is lower.The resistance R_ct of WC-Cr₃C₂-Ni coating is about 30 times of Al₂O₃-40TiO₂ coating, which indicate that the corrosion resistance of WC-Cr₃C₂-Ni coating in 3.5wt%NaCl solution is much better than that of Al₂O₃-40TiO₂ coating.