Zinc phosphate and zinc aluminium phosphate as anticorrosive pigments in epoxy powder coating:EIS study

Epoxy powder coatings have been widely used to protect metal substrates from corrosion [1,2]. Different kinds of organic and inorganic pigments have been used to improve theanticorrosion performance of epoxy powder coatings. Chromates due to their excellent anticorrosion performanceshave been widely used to improve the protection behavior ofthe epoxy coating. However, chromates are toxic and carcinogenic [3,4]. Environmentally regulations becomestricter in recent years. Attempts have been carried out to use environmentally friendly alternatives. Zinc phosphate is one ofthese alternatives. New modifications are performed and new generation of ZP has been produced [3-5]. In this work, theanti corrosive performance of zinc phosphate and zinc aluminum phosphate (first and second generation of phosphate based pigment respectively) in epoxy powder coating was studied using Electrochemical Impedance Spectroscopy (EIS).