Direct electrosynthesis of polyaniline–montmorrilonite nanocomposite coatings on aluminum alloy 3004 and their corrosion protection performance

Homogeneous and adherent polyaniline–montmorrilonite (MMT) nanocomposite coatings were electrosynthesized on aluminum (Al) alloy 3004 (AA 3004) by using the galvanostatic polarization method. The synthesized coatings were characterized by UV–Vis absorption spectrometry, Fourier transform infrared spectroscopy, X-ray diffraction patterns and scanning electron microscopy. The corrosion protection effect of the coatings was demonstrated by performing a series of electrochemical experiments of potentiodynamic and impedance measurements on Al in 3.5 wt% aqueous NaCl electrolytes. The corrosion current (icorr) values decreased from 6.55 μA cm−2 for uncoated Al to 0.102 μA cm−2 for nanocomposite-coated Al under optimal conditions.

► Polyaniline–montmorrilonite nanocomposite coatings were electrosynthesized on Al.
► The corrosion rate was found to be 190 times lower than that observed for uncoated Al.
► The redox catalytic property and the barrier effect were affected on corrosion performance.