Electrochemical impedance spectroscopy investigation of the corrosion resistance of a waterborne acrylic coating containing active electrochemical pigments for the protection of carbon steel

Abstract

The aim of this work was to investigate the corrosion resistance of a water-based commercial paint system applied on carbon steel. Electrochemical impedance spectroscopy (EIS) in the conventional three-electrode configuration was employed to test the various components of the paint system during their exposure to 3 wt.% NaCl aqueous solution. An efficient protection against corrosion was provided by the acrylic polymer containing zinc phosphate pigments when it was applied as a multilayer system. In this way, the high density of pores produced in the polymer matrix during the curing process could be avoided to become direct ionic pathways for the transport of aggressive species from the environment towards the surface of the underlying metal substrate.