Electrochemical behavior and mechanism of CO_2 corrosion on P110 steel in simulated oilfield solution

摘要

Purpose - This paper aims to further investigate the behavior and mechanism in simulated oilfield solution on CO_2 corrosion of P110 steel at various temperatures by potentiodynamic sweep and electrochemical impedance spectroscopy (EIS) measurements, especially discussing the influence of the coverage fraction of corrosion film. Design/methodology/approach - Potentiodynamic sweep and EIS measurements were applied to investigate the behavior and mechanism with the effect of temperature on CO_2 corrosion of P110 steel in simulated oilfield solution at 30℃, 60℃ and 90℃. Findings - The corrosion parameters of polarization curves, such as corrosion potential (Ecorr), corrosion current density (icorr), anodic and cathodic branches slopes (ba andbc), were analyzed and discussed in detail. In addition, the equivalent circuit models and ZsimpWin softwarewere utilized to fit and analyze the Nyquist plots. The plots showed that corrosion potential shifted more negatively as temperature increased. The corrosion current density (icorr) initially increased and then decreased with the increase of temperature. The impedance spectra measured at various temperatures had different time constants. Originality/value - The paper highlights that the coverage fraction u of corrosion film is one most important and key variable influencing CO_2 corrosion mechanisms.