Corrosion inhibition of carbon steel by new enaminonitrile derivatives in HCl Solution

In the present investigation new corrosion inhibitors, enaminonitrile derivatives (1-3) were synthesized characterized and tested as corrosion inhibitors for carbon steel in 1 M HCl using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation techniques. The corrosion inhibition efficiency measured by the above three techniques were in good agreement with each other. Electrochemical polarization data revealed the mixed mode of inhibition. The inhibition efficiency increases with increasing inhibitor concentration. Adsorption of enaminonitrile derivatives 1-3 was found to follow the Temkin adsorption isotherm. The mechanism of inhibition process was discussed in the light of the chemical structure and quantum-chemical calculations of the investigated inhibitors.