Electrodeposition of polypyrrole (PPy) and PPy-metal oxide nanocomposites on mild steel (MS) was carried out in oxalic acid solution by constant potential technique. The protection properties of coatings were studied in 0.5M H2SO4 solution by Tafel polarization and electrochemical impedance spectroscopy (EIS). The effect of different nanoparticles (Al2O3, ZnO, TiO2, CeO2 and SnO2) on the protection performance of the nanocomposite coatings was compared. The results reveal that PPy/Al2O3 nanocomposite provided the best performance for corrosion protection of the MS by reducing its corrosion current density by 18 times. Furthermore, corrosion protection behavior of PPy/nano-Al2O3 and PPy/micro-Al2O3 composites was compared.
