Comparison study on anticorrosion performances of the epoxy coatings with two different nano-polyanilines for Q235 steel

Sulfuric acid doped nano-polyaniline was prepared by direct mixed oxidation in two different systems. A novel approach for preparing polyaniline (PANI) in FeCl2/H2O2 system was developed. The PANI possessed an excellent dispensability. Corrosion protection of epoxy coatings containing two kinds of polyaniline (PANI) on Q235 steel was studied by electrochemical impendance spectroscopy (EIS) technique and Tafel polarization test in 3.5wt% sodium chloride (NaCl) aqueous solution. The results indicated that the epoxy coating containing PANI obtained in FeCl2/H2O2 system had the best performance of the corrosion protection among three systems under investigation. The possible protective mechanism of PANI was discussed.