Anticorrosive behavior of a zinc-rich epoxy coating containing sulfonated polyaniline in 3.5% NaCl solution

An epoxy zinc-rich composite coating containing self-doped conducting sulfonated polyaniline (SPANi) nanofiber was prepared and the corrosion resistance of as-prepared coatings on Q235 substrate studied by open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET). Results suggested that a zinc-rich coating with addition of 1.0 wt% SPANi could enhance the cathodic protection time and barrier performance. To study corrosion diffusion, artificial scratch and adhesion strength were investigated via the salt spray test and pull-off test, respectively. Finally, the passivating action of coatings was demonstrated by analyses of corrosion products via X-ray diffraction spectroscopy.