Effects of Arctostaphylos uva-ursi Extract as Green Corrosion Inhibitor for Cu10Ni Alloy in 1 M HNO3

Abstract

The corrosion inhibition of Cu10Ni alloy by Arctostaphylos uva-ursi extract (AUUE) in 1 M HNO3 has been investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM) and scanning electron microscope (SEM) techniques. Potentiodynamic polarization indicated that AUUE acted as mixed type inhibitor but mainly cathodic. The calculated adsorption thermodynamic parameters indicated that the adsorption was a spontaneous, exothermic process accompanied by an increase in entropy and obey Langmuir adsorption. The inhibition efficiency increases with increasing the concentration of the inhibitor and decreases with increasing the temperature. The SEM results showed the formation of a protective film on the alloy surface in the presence of AUUE. The results obtained from different electrochemical techniques were in good agreement.