Abstract

The inhibition effect of four amino acids on the corrosion of 316L stainless steel in 1.0 M H₂SO₄ has been studied by open-circuit potential and potentiodynamic polarization measurements. Corrosion data such as corrosion rate, corrosion potential (E_Corr.) and corrosion current (I_Corr.) were determined by extrapolation of the cathodic and anodic Tafel region. Glycine, Leucine and Valine inhibit the corrosion process, but Arginine accelerate the corrosion phenomenon. Glycine has the highest inhibition efficiency, its efficiency increases with increasing the concentration to attain 84.2% at 0.1M. Different behaviours were observed, in case of Arginine, corrosion rate increase by increasing concentration. These results show that the presence of Arginine at high concentration turns the surface of 316L stainless steel electrochemically active, probably dissolving the passivation layer and promoting the stainless steel anodic dissolution. Results obtained from potentiodymaic and open-circuit potential measurements are in good agreement.

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