交流杂散电流对剥离涂层下X80钢腐蚀行为研究

摘要： 交流杂散电流严重威胁埋地管道的腐蚀，尤其是管道涂层出现破损时交流杂散电流的影响更为严重和复杂。为此，采用电化学方法、阵列电极技术（WBE）、扫描电镜（SEM）以及X射线能谱分析（EDS）等研究了不同交流杂散电流密度对剥离涂层下X80管线钢腐蚀行为的影响。结果表明：交流杂散电流对X80钢在土壤模拟溶液中的腐蚀起促进作用，其腐蚀产物以铁的氧化物为主，但交流杂散电流干扰会影响腐蚀产物的成分。此外，在氧浓差电池与闭塞电池自催化效应共同作用下，缝隙内部金属一直处于加速溶解状态，且交流干扰的存在，增强了金属的活性，更利于腐蚀的发生。

Effect of AC stray current on corrosion behavior of X80 steel under stripped coating

Stray alternating current (AC) has negative effect on the corrosion of buried pipelines, which might be more serious and complicated when the protective coating was damaged. Therein, the electrochemical test, array electrode technology (WBE), scanning electron microscope (SEM) and X-Ray energy spectrum analysis (EDS) were carried out to study the effect of AC stray current on corrosion behavior of X80 steel under stripped coating. As the results show, AC stray current accelerates the corrosion of X80 steel in the simulated soil solution. The main corrosion products were iron oxides, and the composition of the corrosion products could be affected by the current interference. What’s more, under the combined autocatalytic effect of the oxygen concentration cell and the occlusion cell, the metal inside the gap is in an accelerated dissolution state. Meanwhile, the existence of AC stray current interference enhances the activity of the metal and is more conducive to the occurrence of corrosion.