The Inhibited Effect of Tyrosine Toward copper Corrosion in Nitric Acid Solution

The detailed study of tyrosine (Tyr) as corrosion inhibitor for copper in nitric acid solution has been performed through weight loss, electrochemical polarization, scanning electron microscopy (SEM), X-ray diffraction and FT-IR measurements. The effect of inhibitor concentration, temperature and immersion time against inhibitor action was investigated. Results show that Tyr may be used as an efficient inhibitor for copper in nitric acid at temperature 20°C. Potentiodynamic polarization studies reveal that Tyr acts as a cathodic inhibitor without any change in the mechanism of hydrogen evolution. The adsorption of this compound on copper surface obeys Langmuir’s adsorption isotherm and has a chemisorptions mechanism. Some Quantum Chemical parameters were calculated by the AM1 and MNDO Semi-empirical method to provide further insight into the mechanism of inhibition of the corrosion process