Corrosion protection efficiency of the electrochemically synthesized polypyrrole-azo dye composite coating on stainless steel

• Published in: Progress in organic coatings 2022-08, Vol.169, p.106942, Article 106942
• Main Authors: Yılmaz, Sıla Melahat, Atun, Gülten
• Format: Article
• Language: English
• Subjects: Azo dye; Azo dyes; Composite; Controlled release; Corrosion; Corrosion prevention; Electrode polarization; Electropolymerization; Infrared analysis; Infrared reflection; Infrared spectroscopy; Oxalic acid; Polypyrrole; Polypyrroles; Protective coatings; Spectrum analysis; Stainless steel; Stainless steels; Submerging; Sulfuric acid; Synthesis
• ISSN: 0300-9440; 1873-331X
• DOI: 10.1016/j.porgcoat.2022.106942

The polypyrrole-azo dye (Lanaset-Red-2B) composite coatings were electrochemically deposited on stainless steel 430 by means of repetitive cyclic voltammetry. The composite coatings were synthesized by addition of the dye in 10−6–10−3 M range to 0.1 M oxalic acid solution containing 0.1 M pyrrole monomer. All polypyrrole/Lanaset-Red-2B composite coatings are more protective with respect to the pristine polypyrrole in NaCl (3.5%) medium. The best protective coating synthesized in the presence of 10−5 M dye using optimized potential range, scan-rate and cycle number were characterized by infrared-reflection-absorption-spectroscopy, scanning-electron-microscopy and energy-dispersive-spectroscopy analyses. The electrochemical characterizations were performed by using potentiodynamic polarization and electrochemical-impedance-spectroscopy techniques. The steel coated with the polypyrrole/Lanaset-Red-2B composite is more resistant in 0.1 M H2SO4 solution comparing to NaCl (3.5%) during long-term immersion until 432 h. The corrosion protection efficiency of the coating is higher than that of its initial value at the end of 432 h immersion in both media due to controlled release of the Lanaset-Red-2B deposited as inhibitor in the polypyrrole structure. •The PPy-azodye (LR-2B) composite coatings were electrodeposited on the 430 SS.•The PPy/LR-2B coating inhibits corrosion of the steel in both saline and acid media.•The protection efficiency increases with immersion time in both NaCl and H2SO4 media.•The smart release of the LR-2B inhibitor leads to long-term corrosion protection.