Improving inhibition efficiency of 304 stainless steel using an organic extract in acidic and high temperature environment: Experimental and theoretical studies

Many organic inhibitors have been proposed for corrosion protection of 304 stainless steel (SS), but its effectiveness in acidic and high temperature environment is challenged. We utilized Tithonia diversifolia (Hemsl) A. grey leaf extract (TDLE) as an eco-friendly organic inhibitor to protect 304 stainless steel (SS) in acidic environment (1 M HCl) at high temperature (65 °C). The performance of TDLE was studied electrochemically using potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The surface of the metal was characterized using scanning electron microscopy (SEM). The theoretical calculation was also studied to understand the inhibition process. The corrosion inhibition efficiency increases reaching 98.48 % at 65 °C in the presence of 3.5 g/L TDLE. The inhibition of TDLE on 304 SS surface was adsorption spontaneously based in Langmuir's adsorption isotherm. The SEM images show significant improvement of the 304 SS surface with TDLE. A theoretical study indicates that methyl 3.5-dicaffeoyl quinate is the most active inhibitor in TDLE. The study revealed that TDLE had good performance for inhibiting in acidic and high temperature environment.