Influence of submicron-sheet zinc phosphate synthesised by sol-gel method on anticorrosion of epoxy coating

Submicron-sheet zinc phosphate (SZP) was synthesised by sol-gel method. Anticorrosion behaviour of epoxy coating with SZP was investigated by electrochemical impedance spectroscopy, gravimetric test, adhesion test and scanning electron microscopy. Results showed that the submicron-sheet structure of SZP pigment can reduce defects in the coating, improve consistency of pigment/resin interface and lengthen diffusion pathways. SZP pigments in coating had more contact area with permeating water, ensuring PO43− quickly attained the specific density to inhibit corrosion on the steel surface. Thus, SZP pigment can enhance the barrier properties of coatings and effectively inhibit the corrosion reactions at coating/metal interface.