Investigation of the inhibition effect of indole-3-carboxylic acid on the copper corrosion in 0.5 M H2SO4

Inhibition of the copper corrosion by means of indole-3-carboxylic acid (ICA), was studied in 0.5 M H2SO4 solutions in the temperature range from 25 C to 55 C using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results obtained from the both measurement techniques revealed good inhibitor efficiency in the studied concentration range. Nyquist plots showed depressed semicircles with their centre below real axis. Moreover, the impedance spectra in the case of both non inhibited solutions and inhibited ones by means of lower inhibitor concentrations exhibited Warburg impedance. The adsorption behaviour of ICA followed Langmuir's isotherm. (C) 2008 Elsevier Ltd All rights reserved.