利用EIS等技术研究了常温常压下P110 油管钢在模拟油田采出液中受CO2 腐蚀的电化学行为.结果表明: 附加的阴极反应?H2CO3 的直接还原, 是导致CO2 条件下的活性溶解腐蚀比相同PH 的强酸腐蚀更为严重的主要原因; 模拟介质中的阳极活性溶解过程遵循“PH 依赖机理”, 阴极反应则包括H+ 的还原、H2CO3 的还原、HCO－3 的还原和H2 O的还原“,”EIS and other techniques were used to study the behavior of steel P110 in CO 2 containing simulated oilfield brine at room temperature and pressure. It was found that the most important reason of H 2CO 3 being more corrosive than a completely dissociated acid resulted from an additional cathodic reaction: the direct reduction of H 2CO 3. The impedance spectra at both open circuit potential and anodic potential presented a typical character of three time constants: a capacitive semicircle was followed by an inductive and a small capacitive semicircle at low frequencies. This and other observations suggested that the active dissolution of steel P110 at relatively lower pH in the simulated fluid took place by “pH dependent mechanism”. The cathodic reactions mainly included H + reduction, direct H 2CO 3 reduction, HCO 3 reduction and direct H 2O reduction. The dominance of four reactions in cathodic current changed with pH of the media.