Electrochemical characterizations of different ceramic composite coatings on carbon steel piping using high velocity oxy-fuel spray

Environmental problems have had much attention for saving energy and cost in petroleum industry. For this reason the specification and the use of materials which combine erosion and corrosion resistances with high mechanical strength is a fundamental requirement in petroleum industry. High velocity oxygen fuel (HVOF) is one of the most commonly thermal spraying processes that can be deposited a wide range of chemical composition of material on the top surface of instrument and equipment to protect them from wear and corrosion phenomena. Usually a corrosion resistance of material is measured by electrochemical techniques. Electrochemical behaviors of coatings were mainly investigated by potentiodynamic polarization in sea water (3%NaCl) as a function of process parameters. The results were expected to facilitate the understanding and improvement of the carbon steel piping behavior in sea water. Potentiodynamic polarization and electrochemical impedance spectroscopy show that the HVOF coating of chromium carbide-nickle chromium has the higher corrosion resistance and protects the substrate from NaCl electrolyte penetration.