A study on corrosion protection of different polyaniline coatings for mild steel

The emeraldine base and salt (hydrofluoric acid and camphorsulfonic acid doped) forms of polyaniline (PANI) were synthesized and added to be epoxy coating. The corrosion protection of different PANI coatings was studied by EIS. Results indicated that different PANI coatings could offer the corrosion resistance of mild steel. However, the camphorsulfonic acid-doped PANI coating had the best performance in corrosion protection among the four systems under investigation. The corrosion product layer was analyzed by SEM and XPS, indicating that PANI changed the morphology and component of the corrosion product layer. Moreover, the protective mechanism imparted by PANI was discussed.