采用咪唑啉缓蚀剂对桥梁用环氧涂层进行改性,采用模拟腐蚀试验和电化学试验,研究了改性涂层对海洋干湿交替环境中X80管道钢的腐蚀防护作用。结果表明:随着缓蚀剂含量的增加,X80钢基体的全面腐蚀速率和最大蚀坑深度先迅速下降后缓慢下降,涂层表面明显的孔洞现象减弱,逐渐转变为分层特征,金属基体的点蚀程度逐渐减轻,腐蚀位置与涂层孔洞位置相对应;随着缓蚀剂含量的增加,腐蚀电位增大,自腐蚀电流密度减小,双电层电容减小,电荷转移电阻增大;涂层中缓蚀剂的作用主要是增加涂层的交联密度和消耗腐蚀性介质中的阴离子。

The epoxy coating for bridge was modified by imidazoline corrosion inhibitor. The corrosion protection effect of modified coating on X80 pipeline steel in marine dry-wet alternate environment was studied by simulated corrosion test and electrochemical test. The results showed that with the increase of corrosion inhibitor content, the overall corrosion rate and maximum corrosion pit depth of X80 steel substrate decreased rapidly at first and then decreased slowly. The obvious hole phenomenon on the coating surface gradually weakend and gradually transformed into stratification characteristics. The degree of pitting corrosion of the metal substrate gradually reduced, and the corrosion position corresponded to the hole position of the coating. With the increase of corrosion inhibitor content, the corrosion potential increased, the free corrosion current density decreased, the double layer capacitance decreased, and the charge transfer resistance increased. The role of corrosion inhibitor in the coating mainly included increasing the crosslinking density of the coating and consuming the anions in the corrosive medium.