Comparative study of polyanthranilic acid and sulphonated polyaniline on the mild steel corrosion in aqueous hydrochloric acid
Abhishek Dwivedi, Sudhish Kumar Shukla, Prem Kumar Bharti, Nakul Gupta, Kuldeep K. Saxena, Yagya Dutta Dwivedi
Abstract
Investigation of corrosion in mild steel specimens, using 0.5 N muriatic acid mixture with PANA and SPANI conducting polymers, has been done using Weight Loss (WL), Electrochemical Impedance Spectroscopy (EIS), Potentiodynamic Polarization (PDP), and Surface Morphology. The highest Inhibitor efficiency (IE) reported at 70 ppm for PANA was 86.18%, whereas 89.2% for SPANI, at a temperature of 35±1°C, under 3 h duration. Both polymers exhibit synergistic inhibitor actions at low acid concentrations and temperatures, indicating effective adsorption of polymers on the specimen surface and are seen to satisfy the Langmuir adsorption isotherm and follow cathodic and anodic types of properties. The estimated synergism value is unity, which is only attributed to a synergy that the higher IE in both polymers is achieved by adding surfactants. AFM supports all the above evaluation results. The results conclude that SPANI shows much better characteristics than PANA for the conditions examined.