Effect of Thyme leaves hydroalcoholic extract on corrosion behavior of API 5L carbon steel in 0.5 M H2SO4

In this study,the effect of thyme leaves hydroalcoholic extract (as a green corrosion inhibitor) on corrosion behavior of api 5l carbon steel in 0.5 m h2so4 solution was investigated by tafel polarization and electrochemical impedance spectroscopy (eis). tafel polarization plots showed that thyme is a mixed inhibitor. also,tafel polarization and eis results indicated that the inhibition efficiency increases with increasing thyme leaves hydroalcoholic extract concentration to attain 89% at 12 g/l. impedance parameters change with increasing concentration of extract shows that the adsorption of this extract on the steel surface will form a protective layer on the steel surface. moreover,temkin isotherm revealed that thyme physically is absorbed on api 5l carbon steel surface in 0.5 m h2so4 solution. the adsorption isotherm was obtained -17.86 kj mol-1. © 2016 by cee (center of excellence in electrochemistry).