交流杂散电流对X80管线钢的腐蚀行为影响

目的 研究交流杂散电流干扰下管线钢的腐蚀机理.方法 采用电化学阻抗谱(EIS)、动电位极化扫描(Tafel)等电化学测试技术和表面分析技术研究不同交流电流密度干扰下(0～80 A/m2)X80管线钢在酸性土壤环境中的腐蚀行为.结果 酸性土壤环境中,即使是10 A/m2的交流电流密度,也会引起X80的交流腐蚀,且钢的腐蚀...

Effect of AC Stray Current on Corrosion Behavior of X80 Pipeline Steel

To study the corrosion mechanism of pipeline steel under the interference of alternating current(AC).Electrochemical impedance spectroscopy(EIS),potentiodynamic polarization scanning(Tafel),and surface analysis techniques were used to study the corrosion behavior of X80 pipeline steel in acid soil environment under different AC current density(0~80 A/m2).In acid soil environment,the AC corrosion of X80 can be enhanced even with the AC current density of 10 A/m2,and the corrosion rate of steel increased with the increase of AC current density.The results showed that the corrosion current density of steel coupon in acid soil solution was 9.6μA/cm2 without AC interference,however,it increased to 11.95μA/cm2 when the 10 A/m2 AC was applied.When the AC current density increased to 80 A/m2,the corrosion current density was 2.25 times of that without AC.The weight loss further verified the electrochemical test results.When the AC current density increased to 80 A/m~2,the corrosion rate was 3.5 times that of the non-interfered coupon.Pitting corrosion of X80 steel mainly occured in acid soil environment,and the AC stray current further enhanced the pitting corrosion of X80 steel.The electrochemical corrosion process of X80 steel is affected by the introduction of AC.In the positive half-cycle of AC,oxidation reaction occurs,while reduction reaction occurs in the negative half-cycle of AC.In the whole process of AC,the anodic oxidation of positive half-cycle is much greater than the cathodic reduction of negative half-cycle.