The effects of Hypericum perforatum to electrochemical behaviour of mild steelin 3.5% NaCl solution

The corrosion behaviour of mild steel in 3.5% NaCl solution (pH=4.0, 6.0, and 8.0) with the absence and presence of Hypericum perforatumhas been investigated by electrochemical techniques such as potentiodynamic polarization, open circuit potential and electrochemical impedance spectroscopy (EIS). The optimum concentration of the studied inhibitors showing highest inhibition efficiency was also evaluated at constant temperature (298 K; pH=4.0). The inhibition efficiency was found to increase with an increase in concentration of Hypericum perforatum. Thermodynamic parameter for the adsorption process were determined. Scanning electron microscopy (SEM) observations of the copper surface confirmed the existence of such an adsorbed film.