The environmental friendly inhibitor system L-alanine-Zn²⁺ has been investigated by weight loss method. A synergistic effect exists between L-alanine and Zn²⁺ system. The formulation consisting of L-alanine - Zn²⁺ offers good inhibition efficiency. Polarization study reveals that this formulation functions as an anodic inhibitor. AC impedance spectra reveal that a protective film is formed on the metal surface. A suitable mechanism of corrosion inhibition is proposed based on the results obtained from weight loss study and electrochemical studies. At isoelectric point, the IEs of L-alanine and also the L-alanine-Zn²⁺ systems are very low. In some cases there is acceleration of corrosion (negative IEs).
Keywords:  Corrosion; Carbon steel; L- Alanine; Polarization study; AC impedance spectra