Inhibition of Copper Corrosion in NaCl Solution by Propolis Extract

This study investigates the possibility of corrosion inhibition of copper by propolis extract in 0.51 mol dm(-3) NaCl solution. The influence of propolis extract concentration and temperature on corrosion behaviour of copper was studied using electrochemical methods. The protective effect of propolis coating deposited on the electrode surface and dried in air was also examined. The results of the study showed that with increasing propolis extract concentration in the solution there was a slight increase in open circuit copper potential to positive values, an increase in polarization resistance. and a decrease in the corrosion current density. A significantly more prominent change of all three of these parameters was observed in the case of propolis coating. Potentiodynamic measurements indicate that propolis extract acts as a mixed corrosion inhibitor, which is adsorbed on the electrode surface according to Langmuir's isotherm. The decrease in inhibition efficiency with increasing temperature indicates physical adsorption. Adsorption of propolis on the electrode surface was confirmed by the spectrophotometric method.