Curcumine Longa: Green and Sustainable Corrosion Inhibitor for Aluminum in HCl Medium

The inhibition effect of Curcumine Longa (CUR) on the corrosion of aluminum in presence of 1 M HCl solution was studied by weight loss, Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), quantum chemical calculations and SEM techniques. Weight loss and electrochemical results showed that inhibition efficiency of CUR increases with increase in the concentration and attained a maximum value of 89.60% at 100 ppm concentration. Polarization study revealed that CUR acts as mixed type inhibitor whereas EIS study showed that the CUR inhibits aluminum corrosion by getting adsorbed at metal/ electrolyte interfaces which followed the Langmuir adsorption isotherm. SEM study confirmed the film forming ability of CUR on the aluminum surface. Quantum chemical calculations study was performed to provide insight into adsorption behavior of CUR on the aluminum surface. Experimental and theoretical results were in good agreement and well complimented to each other.