N80钢CO_2腐蚀过程的EIS研究

EIS Investigation on the CO_2 Corrosion Behavior of N80 Steel

应用电化学阻抗谱研究了N80钢在饱和CO2的模拟地层水中CO2腐蚀过程的电化学行为。结果表明:在饱和CO2的模拟地层水中阻抗谱出现三个时间常数,分别对应高频的容抗弧,中低频的感抗弧和低频的容抗弧。阳极极化条件下的阻抗谱与自腐蚀电位下的阻抗谱形状相同,表明腐蚀机理未发生改变。但极化条件下反应电阻下降,反应速率加快。阴极极化条件下,阻抗谱未出现感抗弧,表明阴极过程不存在吸附中间产物。

The impedance spectroscopies of CO2 corrosion process formed on NSO steel in saturated stratum water with saturated CO2 environment, were detected using electrochemical impedance spectroscopy （EIS）. The results show that three time constants appeared in the impedance spectroscopy in simulated stratum water with saturated CO2 environment, which corresponded to the capacitance in high frequency, the inductance in middle frequency and capacitance in low frequency respectively. The figures of the spectroscopies measured at anodic polarization and measured at self-corrosion potential were similar, indicating the same corrosion mechanism under two measured conditions. But the reaction impedance decreased, and then the corrosion rate increased. Under the cathodic polarization condition, there is no inductance appearing in the spectroscopy, whcih showed that no absorption materials existed in the cathodic corrosion process.