红壤模拟溶液中Cl-对X80管线钢腐蚀行为的影响

摘要

In this paper, the effect of Cl- ion on the corrosion behavior of X80 pipeline steel was monitored in an red soil by linear polarization curve, electrochemical impedance spectroscopy and scanning electron microscope. The results showed that, in the simulated acidic soil solution without Cl- ion, general corrosion is the main corrosion type for the X80 pipeline steel. When trace amounts of Cl- ion was introduced into the soil solution, the general corrosion is destroyed, and the corrosion type changes into localized corrosion. Within the range tested, the number and depth of the localized corrosion increase with the increase of Cl-ion. In the soil solution with Cl- ion, the impedance of X80 pipeline increases in the initial stage of the experiment, then decreases, and remains stable in the last stage. The effect of Cl- ion on corrosion behavior of pipeline steel buried in red soil could be taken into account in the practice of project.%利用线性极化曲线、电化学阻抗谱和扫描电子显微镜等方法研究了模拟酸性红壤中Cl-对X80管线钢腐蚀行为的影响。结果表明，在不含Cl-的模拟酸性土壤溶液中，X80管线钢主要发生均匀腐蚀；当存在低浓度的Cl-时，X80管线钢的均匀腐蚀遭到破坏，发生局部腐蚀；在本文测试范围内随着Cl-浓度的增加，点蚀坑数量增多，点蚀坑的直径增大，X80管线钢耐局部腐蚀性能下降。在含Cl-的溶液中，随着浸泡时间增加X80管线钢阻抗值先增大后减小，最后保持稳定。根据本文研究结果，铺设于酸性红壤中的管线钢必须考虑Cl-对其腐蚀行为的影响。