Electrosynthesis of PAni/PPy coatings doped by phosphotungstate on mild steel and their corrosion resistances

Polyaniline/polypyrrole (PAni/PPy), polyaniline-phosphotungstate/polypyrrole (PAni-PW12/PPY) and PAni/PPy-PW12 have been successfully electrodeposited on mild steel (MS) by cyclic voltammetry in aqueous oxalic acid solutions. It was found that the incorporation of PW12 enhanced the corrosion resistance of PAni/PPy coating. Moreover, in comparison to PAni-PW12/PPy, PAni/PPy-PW12 coating exhibited better corrosion resistance for mild steel. After immersion of 36h in 0.1 M HCI, for instance, the polarization resistance of PAni/PPy-PW12 coating reached 1695 Omega cm(2), more than those of both PAni/PPy and PAni-PW12/PPy. (C) 2015 Elsevier B.V. All rights reserved.