Medicago sativaas a green corrosion inhibitor for 1018 carbon steel in 0.5 M H₂SO₄solution

Abstract

A study on the use of the methanol extract of Medicago sativa as a green corrosion inhibitor for 1018 carbon steel in 0.5 M of sulfuric acid has been carried out by using potentiodynamic polarization curves, electrochemical impedance spectroscopy and gravimetric tests. Testing temperatures were 25°C, 40°C and 60°C. Results showed that M. sativa is a good corrosion inhibitor, with its efficiency increasing with its concentration and with time, but decreasing with the temperature. M. sativa forms a passive film on top of the steel with a passive current density and pitting potential values lower than that for uninhibited solution, and remained on the steel for 8-12 h. This film formed by iron ions and heteroatoms present in OH − and amine groups from the extract are adsorbed on the steel and form a protective film on to the steel. ARTICLE HISTORY

Corrosion inhibition of C-steel in acidic media from fruiting bodies of Melia azedarach L extract and a synergistic Ni2+additive

“…5 Many plant extracts have been used as effective corrosion inhibitors of iron and steel in acidic media. Examples of these plants are: Artemisia mesatlantica, 6 Murraya koenigii leaf, 7 strawberry fruit, 8 Medicago sativa, 9 Morinda tinctoria leaves, 10 Santolina chamaecyparissus, 11 Spirogyra algae 12 and Melia azedarach Linn (MAL) seeds. 13 Most green corrosion inhibitors are obtained from methanol, ethanol, aqueous, acid, or formaldehyde extracts of plant materials.…”

Ethanolic extract of Chrysophyllum albidum leaves and peels as a green inhibitor for AISI 1015 carbon steel in 1M H2SO4 solution

“…These atoms form bonds with the steel top surface electrons, hence minimizing the corrosion effect of the test medium. [ 48 ] It is also worthy of note that the mechanism of electrochemical corrosion of MS in H 2 SO 4 acid are: Fe → Fe 2+ + 2e (the anode process) and 2H + + 2e → H 2 (the cathode process).…”

KI effects on corrosion inhibition for 1018 steel in acid media using Medicago sativa

“…The corrosion current density increases initially when adding 1 and 2.5 mM of KI; thus, the efficiency values decrease ( Rodríguez Torres et al, 2016 ). However, by increasing the KI concentration to 5 mM, the current density decreases and the efficiency rises to 97%.…”

“…To prepare the inhibitory solution, 500 ppm of M. sativa extract was used, as it was considered the best concentration as previously reported ( Rodríguez Torres et al, 2016 ). We added different KI concentrations (1–5 mM) to evaluate the effect of halide ions on inhibition efficiency.…”

“…Medicago sativa (M. sativa) extract has been previously proved as a corrosion inhibitor for 1018 steel in acid media showing a maximum efficiency of 90% after 8 h, and it maintained until 12 h. After this time, the inhibition efficiency decreases ( Rodríguez Torres et al, 2016 ). The aim of the present work is to evaluate the effect of adding different concentrations of KI when using M. sativa as a corrosion inhibitor for 1018 steel in 0.5 M of H 2 SO 4 .…”