Surface Modification of Mild Steel by Orthophenylenediamine and Its Corrosion Study

An attempt has been made towards the synthesis of strongly adherent orthophenylenediamine (OPD) coating on mild steel substrates, with an objective of using the OPD for corrosion protection of steel in hydrochloric acid medium. In this work, the OPD coatings were obtained by electrochemical reduction of orthonitroaniline (ONA) using dilute sulphuric acid as supporting electrolyte. The characterization of the coating was done by infrared spectroscopic and scanning electron microscopic studies. The non porous nature of the coating was determined by ferroxyl test. The performance of OPD as protective coating against corrosion of mild steel in aqueous hydrochloric acid was assessed by open circuit potential, potentiodynamic polarization, weight loss method. These studies revealed that the OPD coating on mild steel provide very good protection to mild steel against corrosion in hydrochloric acid environment