Effect of serine, threonine and glutamic acid on the corrosion of copper in aerated hydrochloric acid solution

The corrosion inhibition of three amino acid compounds on copper was investigated by electrochemical method. They suppressed cathodic current densities and shifted the corrosion potential towards more negative values. The interaction between amino acid and copper surface was certified by reflected FT-infrared spectroscopy. The quantum chemical parameters were obtained by PM3 semi-empirical calculation. Glutamic acid has the smaller net positive charge of nitrogen atom and the more net negative charge of oxygen atoms. The improved inhibition of glutamic acid was due to the stabilization of its adsorption on the copper surface by the oxygen atoms in its structure.