The effect of polypyrrole coating on the corrosion of copper and brass

In this study, the effect of polypyrrole coating on the corrosion of industrially important copper and brass was investigated in three corrosive media (0.1 M HCl, 0.1 M NaCl, and 0.1 M NaOH). The polypyrrole coating was applied using electro-polymerization in a 0.1 M oxalic acid solution containing 0.1 M pyrrole. Electrochemical behavior of copper and brass in corrosive media was determined using cyclic voltammetry, and the corrosion rate was assessed using the Tafel polarization method. Polypyrrole coating exhibited effectiveness in all corrosive media. In all three corrosive media, the polypyrrole coating increased the polarization resistance of copper and brass while reducing the corrosion rate. The highest corrosion rate was observed for both metals in the 0.1 M HCl solution, whereas the lowest corrosion rate occurred in the 0.1 M NaOH medium. Specifically, the highest corrosion rate for copper in the 0.1 M HCl medium was determined to be 1.740 mm/year, while the lowest corrosion rate for polypyrrole-coated copper electrode in the 0.1 M NaOH medium was 0.025 mm/year. The best coating efficiency (92.38%) was achieved for polypyrrole-coated copper in the 0.1 M NaOH medium.