Investigation of inhibition effect of some amino acids against steel corrosion in HCl solution

The inhibition effect of three amino acids against steel corrosion in HCl solutions has been investigated by potentiodynamic polarization method. Corrosion data such as corrosion rate, corrosion potential (Ecorr) and corrosion resistance (Rp) were determined by extrapolation of the cathodic and anodic Tafel region. Adsorption isotherm was investigated by weight-loss measurement. The used amino acids were alanine, glycine and leucine. The effect of inhibitor concentration and acid concentration against inhibitor action was investigated. The inhibition efficiency (IE) depended on the type of amino acid and its concentration. The inhibition effect ranged from 28 to 91%. The amino acids act as a corrosion inhibitor in HCl solution through adsorption on the steel surface and adsorption follows Langmuir isotherm. # 2003 Elsevier B.V. All rights reserved.