管道聚乙烯类防腐层的抗阴极剥离性能

Anti-disbonding property of polyethylene coating of pipeline

采用电化学阻抗谱(EIS)的方法,测定了目前埋地钢质管道外防腐中使用最为广泛的3PE防腐层、聚乙烯热收缩套、聚乙烯热收缩带的阻抗变化。通过选用适合的电路对阻抗谱图进行拟合,得到了3种聚乙烯类防腐层在不同实验条件下电阻值的变化规律。研究了3种聚乙烯类防腐层在不同阴极极化电位下抗电解质渗透和阴极剥离的性能。结果表明:随着阴极极化电位的负移和实验时间的延长,试样的电阻值明显减小,在过负的极化电位下表现为急剧减小。证明过负的阴极极化电位使电解质更容易渗透防腐层,致使防腐层提前失效。

The impedance change of 3PE coating, PE heat shrinkable sleeve and/or shrinkable tape that have been widely used for external corrosion control of buried steel pipeline with the electrochemical impedance spectroscopy (EIS) method is measured. By means of fitting impedance spectrum with appropriate circuit, the change law of resistance values of 3 kinds of polyethylene coatings under different experimental conditions is obtained. The researchers carry out a study on the anti-electrolyte permeability property and anti-disbonding of the three polyethylene coatings under different cathodic polarization potentials. Result shows that with a negative shift of cathodic polarization potentials and elongation of experimental time, the resistance of samples is reduced obviously, which appears a sharp decrease under beneath polarization potential. This answer displays that too great a negative polarization potential will more easily result in infiltration of electrolytes to coating, causing earlier failure of coating.