Polyaniline/g-C3N4composites as novel media for anticorrosion coatings

In this paper, graphitic carbon nitride (g-C3N4) was first proposed for the pioneer application of anticorrosion coatings. Original g-C3N4was facilely treated using HNO3and the exfoliated g-C3N4sheets (E-g-C3N4) were fabricated, and then, polyaniline/E-g-C3N4composites (PANI/E-g-C3N4) as novel anticorrosive media were synthesized by chemical oxidative polymerization and devoted to the corrosion protection of coatings. The E-g-C3N4sheets and PANI/E-g-C3N4composites were characterized by X-ray diffraction, Fourier transform infrared, thermogravimetric analysis, and transmission electron microscopy. The anticorrosion properties of the samples prepared were investigated by electrochemical measurements including Tafel plots, electrochemical impedance spectra, and open-circuit potential. Accelerated corrosion tests of iron panels coated by PANI/E-g-C3N4were performed in 3.5 wt% NaCl solution. Anticorrosive mechanism of PANI/E-g-C3N4was discussed in detail. PANI/E-g-C3N4-3 fillers possessed superior corrosion inhibition than individual components on iron coatings, which was due to the synergetic effect of anticorrosion between E-g-C3N4and PANI.