Adsorption and Corrosion Inhibition Behavior of L-Cystine and Synergistic Surfactants Additives on Mild Steel in 0.1 M H₂SO₄

Abstract

The adsorption and corrosion inhibition behavior of mild steel in 0.1 M H₂SO₄ in presence of L-cystine and L-cystine in combination with surfactants sodium dodecyl sulfate and cetyltrimethyl ammonium bromide at 30–60°C was investigated using weight loss and potentiodynamic polarization measurements. Inhibition efficiency of L-cystine is synergistically enhanced on addition of surfactants. Surface morphology of corroded steel samples was evaluated using scanning electron microscopy and atomic force microscopy, which further confirmed the existence of an adsorbed protective film on the mild steel surface. Calculated thermodynamic parameters reveal that adsorption process is spontaneous and obey Langmuir adsorption isotherm.

Keywords:

• AFM
• corrosion inhibition
• L-cystine
• mild steel
• SEM
• surfactants