Understanding the corrosion inhibition effectiveness using Senecio anteuphorbium L. fraction for steel in acidic media

•Different families of Senecio anteuphorbium L. are used as an eco-friendly corrosion inhibitor for S300 steel in 1M HCl using PDP and EIS techniques.•The essential oil and the alkaloid fractions reveal a good corrosion inhibition efficiency.•The excellent performance capacity of these compounds is due to the formation of the barrier film onto the steel surface.•Characterization of the steel surface shows the formation of a protective layer with hydrophobic character. The effect of various families of Senecio anteuphorbium L. on the corrosion inhibition of steel S300 in hydrochloric acid was investigated using electrochemical techniques such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). Segregation of various families present in Senecio anteuphorbium L. were extracted and evaluated on corrosion inhibition. The essential oil, represents the majority part and consists mainly of sesquiterpenes, especially γ-selinene, cyperene, γ-cadinene and α-cyperone, which show good inhibition efficiency as the alkaloids group. The inhibition efficiency for the tested groups achieves the values varying from 75 % to 90 % involving the synergistic effect. The excellent performance of these compounds due to the formation of the barrier film on the steel surface. The morphology of the steel surface was examined using scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) spectroscopy to verify and evaluate the composition of the adsorbed film. The wettability behavior of the steel surface performed confirms the hydrophobic character of the formed film. The Fourier transform infrared spectroscopy (FTIR) and UV-Visible techniques provide powerful information's about the adsorption of inhibitor's molecules onto the steel surface. [Display omitted]