Relevance of electrochemical and surface studies to probe zanthoxylum schinifolium (sichuan pepper) as an effective corrosion inhibitor for N80 steel in CO₂ saturated 3.5% NaCl solution

Abstract

The inhibition of the corrosion of N80 steel in 3.5 wt.% NaCl solution saturated with CO₂ by the extract of Zanthoxylum schinifolium (ZSE) has been studied using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Inhibition efficiency was found to increase with increasing concentration of the extract. The adsorption of the extract on the N80 steel surface obeyed the Temk in adsorption isotherm. Values of inhibition efficiency calculated from potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) are in good agreement. Polarization curves showed that ZSE behaves as a mixed-type inhibitor in NaCl solution. The adsorbed film on N80 steel surface containing inhibitor was confirmed by the XRD, SEM results. The results obtained showed that the ZSE could serve as an effective inhibitor of the corrosion of N80 steel in 3.5% NaCl saturated with CO₂.