Corrosion Protection of Mild Steel by Polyaniline/Tin-Doped Titania Nanocomposite

This study employed the template-free chemical oxidative polymerisation method to synthesise polyaniline (PANI) and polyaniline/tin-doped titania (PANI/Sn-doped TiO2) nanocomposite as corrosion inhibitors. FTIR and XRD were employed to characterise the chemical composition of the prepared samples. TEM and FESEM microscopy validated the presence of the PANI and that the Sn-doped TiO2 nanoparticle were successfully incorporated into PANI to form the nanocomposite. The synthesised materials were mixed in the polyvinyl butyral (PVB) binder, coated onto mild steel substrates, and exposed to 3.5 wt.% NaCl solution for 30 days. Altogether, three coating systems were tested, i.e., pure PVB, PVB + PANI, and PVB + PANI/Sn-doped TiO2. The corrosion parameters were measured via EIS and Tafel polarisation techniques. Overall, the PANI/Sn-doped TiO2 nanocomposite as a corrosion inhibitor effectively inhibited the corrosion of the mild steel, and its corrosion rate was 3.484 x 10-7 mm/year.