Performance studies of phosphate-doped polyaniline containing paint coating for corrosion protection of aluminium alloy

Polyaniline-phosphate polymer was prepared chemically by oxidation polymerization of aniline in phosphoric acid medium using ammonium persulphate. The PANI-phosphate polymer was characterized by FTIR, XRD, and SEM. The paints using PANI-phosphate as pigment in acrylic and epoxy binder were prepared. The protective performance of the coating formed on aluminum alloy AA 2024 T3 was studied by electrochemical impedance spectroscopy in 0.5% NaCl solution. Both the coating systems have exhibited the coating resistance values above 1M Omega cm(2) even after 50-days exposure in 0.5% NaCl solution. Besides the anticorrosion performance of PANI-containing coating is comparable with that of chromate-containing coating. (c) 2007 Wiley Periodicals, Inc.