Preparation of (Ni-P)/(TiO₂/ZnO) Composite Coating and its Anti-corrosion Behavior in Natural Seawater

(Ni-P)/(TiO2/ZnO) composite coatings were prepared on carbon steel by electroless deposition technique and sol-gel method. The surface morphology and phase composition of the coating were characterized by optical microscopy, scanning electron microscopy, and X-ray diffraction. The anti-corrosion behavior in natural seawater was assessed by measurements of potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results showed that the (Ni-P)/(TiO2/ZnO) composite coating had better anti-corrosion behavior than the Ni-P coating. The composite coating fabricated by preparing TiO2/ZnO thin films directly on the Ni-P coating and then processing heat treatment at 350℃ had the best anti-corrosion property in seawater.