采用阴极保护联合3PE防腐蚀层的方法对埋地钢质管道进行了防护。试验模拟了管道3PE防腐蚀层底漆存在、金属基体暴露、金属暴露孔处未与土壤介质接触及与土壤介质完全接触的不同情况, 探讨了阴极电流与通电电位之间的关系, 研究了通/断电位的负移对试样3PE防腐蚀蚀层阴极剥离的影响。结果表明, 试样阴极保护电流的变化与管道3PE防腐蚀层的缺陷存在、土壤接触方式、通电电位密切相关。通/断电电位正于-0.85 V(CSE)时, 难以阻止试样发生腐蚀, 通/断电位过度负移将造成3PE防腐蚀层的阴极剥离, 使3PE防腐蚀层提前失效。

Buried steel pipelines were protected by the method of 3PE anti-corrosive coating associated with cathodic protection. Different conditions, such as that 3PE anti-corrosive coating primer existsed, metal substrate exposed, metal exposed holes did not contact or contact completely with soil, were simulated. The relationship between cathodic current and potential was discussed, the influence of coating potential moved to negative analyzed too. The results show that the variation of cathodic protection current of the samples was bound up with the defect of the 3PE anti-corrosion coating of the samples, the ways contacted with soil and the impressed current. When the potential is higher that -0.85 V(CSE), it is difficult to prevent the samples from corrosion. When the potential moved to negative direction excessively, the protection of 3PE anti-corrosion coating was early invalidatied.