Synergistic Corrosion Inhibition Effects of Coptis Extract/Berberine and Thiourea on the Corrosion of Mild Steel in Carbon Dioxide Saturated Brine Solution

摘要

The synergistic inhibition effects of the coptis extract (CP)/berberine (BB) and thiourea (TU) on thecorrosion of mild steel in 3% NaCl solution saturated with CO2 at 60 ?C was investigated bypotentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and X-rayphotoelectron spectroscopy (XPS) methods. CP and BB act as moderate inhibitors, and inhibitionefficiency of the former is higher than that of the latter. The adsorption of them obeys Langmuiradsorption isotherm. The inhibition performance was significantly improved by the combined use ofthem with TU, and obvious synergistic corrosion inhibition effect was achieved.