The Effect of Cysteine on the Behaviour of Copper in Neutral and Alkaline Sulphate Solutions

• Published in: International journal of electrochemical science Vol. 7; no. 10; pp. 9043 - 9057
• Main Authors: Petrović, Marija B., Radovanović, Milan B., Simonović, Ana T., Milić, Snežana M., Antonijević, Milan M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-10-2012
• Subjects: copper; corrosion; cysteine; polarization; sulphate; copper; corrosion; polarization; sulphate; cysteine
• ISSN: 1452-3981; 1452-3981
• DOI: 10.1016/S1452-3981(23)16179-7

The behavior of copper in the presence of cysteine in the concentration range 1∙10-6 M - 1∙10-2 M in a 0.5 M Na2SO4 solution (pH 7 and pH 9) is studied using potentiodynamic polarization and chronoamperometry. Potentiodynamic polarization shows that cysteine acts as a copper corrosion inhibitor both in alkaline and neutral sulphate solutions. The inhibitory action occurs through Cu(I)ads, which participates in the formation of the Cu(I)-cys film on the metal surface. At higher anodic potentials Cu(II)ads occurs, which is unfavourable for the adsorption of cysteine. The efficiency of corrosion inhibition increases as cysteine concentration increases. Chronoamperometry results are in accordance with the results of potentiodynamic polarization. The adsorption of cysteine proceeds according to the Langmuir adsorption isotherm.