Corrosion inhibition of carbon steel in solutions containing H2S and HCl by using the Salvia officinalis extract was studied by the Tafel polarization and electrochemical impedance spectroscopy (EIS) methods. Tafel polarization and EIS results revealed that the protection efficiency increases with increasing inhibitor concentration to attain 93% at 7.5 g/l inhibitor. Also, the Tafel polarization plots showed that current inhibitor acts as a mixed type inhibitor. It was found that inhibition occurs due to the physical absorption of inhibitor on the metal surface that follows from longmuir isotherm.
