Carbon dioxide corrosion of carbon steel and corrosion inhibition by natural olive leaf extract

The corrosion of carbon steel in carbon dioxide saturated chloride carbonate solution with and without olive leaf extract at 25 °C and 65 °C has been studied by linear polarization resistance technique, electrochemical impedance spectroscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. In the absence of olive leaf extract, the corrosion products created under the testing conditions within 24 h at both testing temperatures have no significant protective properties. Measurements for uninhibited systems showed high corrosion current densities and low polarization resistances of carbon steel. Both linear polarization resistance technique and electrochemical impedance spectroscopy measurements reveal that olive leaf extract inhibits the carbon steel corrosion. The addition of a low‐concentration olive leaf extract decreases corrosion current densities, increases charge transfer and polarization resistance, resulting in more uniform and smoother steel surfaces. These effects are attributed to the adsorption of olive leaf extract on the carbon steel surface.