The environmental friendly inhibitor system glycine-Zn2+, has been investigated by weight loss method. A synergistic effect exists between glycine and Zn2+ system. The formulation consisting of 250 ppm of glycine and 50 ppm of Zn2+ offers good inhibition efficiency of 82%. Polarization study reveals that this formulation functions as an anodic inhibitor. The FTIR spectra study leads to the conclusion that the Fe2+ -Gly complex formed on anodic sites of the metal surface controlled the anodic reaction and Zn(OH)2 formed on the cathodic sites of the metal surface controlling the cathodic reaction. The surface morphology and the roughness of the metal surface have been analyzed with atomic force microscopy. A suitable mechanism of corrosion inhibition is proposed based on the results obtained from weight loss study and surface analysis technique. The eco-friendly inhibitor glycine-Zn2+ system may find application in cooling water system.
Key words: Glycine, corrosion inhibitor, synergistic effect, carbon steel, well water, zinc ion, amino acids.
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