Black Tea as Green Corrosion Inhibitor for Carbon Steel in 1 M Hydrochloric Acid Solutions

Corrosion inhibitors from natural products have been considered preferential due to the environment friendly effect. Black tea was tested as corrosion inhibitor for carbon steel in 1 M HCl solution using electrochemical frequency modulation (EFM), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) techniques. The inhibition efficiencies obtained from all techniques employed are in good agreement with each other. Potentiodynamic polarization measurement indicates that black tea acts as a mixed type inhibitors. The adsorption of the extract on carbon steel is found to obey Temkin adsorption isotherm. SEM study confirmed the adsorption of the extract molecules on the carbon steel surface.