Electrochemical Behavior of Polyterthiophene-Coated Types 304 and 316 Stainless Steels and Its Corrosion Performance

Polyterthiophene (P3T) film was synthesized on Types 304 (UNS S30400) and 316 (UNS S31600) stainless steel (SS) electrodes from an acetonitrile (ACN) solution containing 10^–2 M terthiophene (3T) and 10^–1 M lithium perchlorate (LiClO₄), by cycling voltammetry between 0 and 1.20 V, with a scan rate of 25 mV/s. The electrochemical behavior of the SS samples with and without polymer films were studied in 0.5 M sulfuric acid (H₂SO₄) and 3% sodium chloride (NaCl) solutions, using cyclic voltammetry, electrochemical impedance spectroscopy (EIS), and open-circuit potential measurements. It was shown that homogeneous and adherent P3T films deposited on the electrode surface reduce the corrosion rate of SS, but it does not protect the metal completely against corrosion. The obtained results were promising for using the conducting polymers in corrosion protection.