交流电流作用下X80钢在碱性溶液中阴极保护准则的适用性能

Cathodic Protection Criterion Applicability of X80 Steel with Alternating Current Interference in Alkaline Solution

采用极化曲线、电化学阻抗谱(EIS)、SEM等方法研究了不同交流电流密度条件下X80钢在0.5mol/L NaHCO3溶液中-850mV(vs.CSE)阴极保护准则下的腐蚀特征。结果表明,当阴极Tafel斜率大于阳极Tafel斜率时,X80钢交流电腐蚀较轻,当阴极Tafel斜率远小于阳极Tafel斜率时,X80钢发生交流电腐蚀;随着交流电流密度的增加,腐蚀产物膜电阻及电荷转移电阻均出现了波动,但总的趋势是减小的,表明X80钢不断发生交流电流腐蚀;最后确定了阴极保护准则下交流电流腐蚀防护范围。

The corrosion characteristics of X80 steel in 0. 5 mol/L NaHCO3 solution under the condition of different alternating current （AC） densities with the --850 mV （CSE） cathodic protection criterion was studied by polarization curves, electrochemical impedance spectroscopy（EIS） and SEM. The results show that when the cathodic Tafel slope was greater than the anodic Tafel slope, XS0 steel AC current corrosion was lighter, when the cathodic Tafel slope was less than the anodic Tafel slope, the steel was bound to an AC current corrosion. With the increase of AC density, the corrosion product film resistance and the charge transfer resistance exhibited fluctuation, but the general trend was decrease, indicating that X80 steel suffered corrosion constantly. Finally the alternating current corrosion protection scope under the cathodic protection criteria was determined.