MARIAN BOBINA, NICOLAE VASZILCSIN, CORNELIA MUNTEAN INFLUENCE OF TRYPTOPHAN ON THE CORROSION PROCESS OF CARBON STEEL IN AQUEOUS WEAK ACID SOLUTIONS
Electrochemical behaviour of tryptophan as inhibitor in the corrosion process of carbon steel in acetic acid /acetate solution has been investigated by linear polarization, cyclic voltammetry and scanning electron microscopy. Tafel polarization method was used in order to investigate the influence of tryptophan as corrosion inhibitor at room temperature. The corrosion potential, resistance and corrosion rate have been determined by extrapolating Tafel slopes. These diagrams show that the tryptophan is a good corrosion inhibitor for carbon steel in weak acid media, and its inhibition efficiency increases with the increase of concentration in the range of 10-4 - 10-2 mol L-1. Scanning electron micrographs of the carbon steel surface revealed that tryptophan inhibits the corrosion process, due to his ability to adsorb on the metal surface. Also, the corrosion rate of carbon steel in the studied media has been determined by gravimetric method.
Keywords: tryptophan, corrosion inhibitor, Tafel polarization, scanning electron microscopy