Corrosion Inhibition Character of Azure B for Mild Steel in Hydrochloric Acid Solution

The corrosion inhibition behavior of azure B (AB) on mild steel in 0.5 M hydrochloric acid medium was investigated by gravimetric, potentiodynamic polarization and electrochemical impedance measurements. The inhibition efficiency of AB showed an improvement with increasing concentration up to a critical value of AB, beyond this concentration no further effectiveness is observed. The adsorption of AB on mild steel surface was found to obey Langmuir adsorption isotherm. The synergetic effect was also studied between AB and KI, and the addition of KI enhances the inhibition efficiency of AB significantly. Quantum chemical parameters were used to correlate the inhibition efficiency and molecular structure of AB. Further, the surface adsorbed film was analyzed by scanning electron microscopy.