Evaluating the Corrosion Protection Behavior of Cysteine Amino-Acid on the St۱۲ Steel in the Neutral Chloride Media

In this study, evaluating the inhibitive mechanism of L-Cysteine through comparing its performance with the N-Acetyl-L-Cysteine compound on the mild steel in the sodium chloride medium is the main object. In this investigation, electrochemical impedance spectroscopy technique was used for electrochemical studying and corrosion protection evaluation in the absence and presence of L-Cysteine and N-Acetyl-L-Cysteine compounds. Also, surface studies using scanning electron microscopy was used to study the samples immersed in the L-Cysteine-containing solution. Results showed that LCysteine form an effective adsorbed layer on the steel surface due to the presence of amine and thiol groups. However, N-Acetyl-L-Cysteine showed insufficient inhibition and even more, increase the corrosion rate of steel. According to the results, inhibition efficiency was about ۶۱ percent in the present of L-Cysteine. The impedance resistance increase from ۹۰۰ ohm.cm۲ to ۲۳۰۰ ohm.cm۲ in the presence of L-cysteine after ۶ h immersion. The valuable results about the corrosion control potential of LCysteine as an amino acid in the neutral medium is proposed in the present investigation. It seems that, by removing amine group presented in the L-cysteine structure and its deactivation in the form of NAcetyl- L-Cysteine, the compound could not show any acceptable anti-corrosion performance for mild steel.

کلیدواژه ها:

Corrosion inhibitor ، L-Cysteine ، N-Acetyl-L-Cysteine ، Steel ، Mechanism ، بازدارنده خوردگی ، ال سیستئین ، ان استیل ال سیستئین ، فولاد ، مکانیزم