Effect of cathodic protection on corrosion of pipeline steel under disbonded coating
Effect of cathodic protection on corrosion of pipeline steel under disbonded coating
复制标题
DOI：
10.1016/j.corsci.2009.05.027
复制
发表时间：
2009-09-01
影响因子：
8.3
通讯作者：
Cheng, Y. F.
中科院分区：
文献类型：
--
作者：
Chen, X.;Li, X. G.;Cheng, Y. F.
利用自行研制的阴极保护试验装置，通过测量局部电位、溶液pH值和溶解氧浓度，研究了阴极保护（CP）对X70管线钢在脱粘涂层下缝隙区域腐蚀的影响。结果表明，在钢筋腐蚀的早期阶段，由于几何尺寸的限制，阴极保护剂不能到达缝隙底部保护钢筋不受腐蚀。钢的腐蚀优先发生在缝隙内，这是由于缝隙溶液中溶解氧的耗尽导致阳极和阴极反应的分离。阴极保护剂在缓解脱粘涂层下缝隙中钢的顺序腐蚀中的主要作用是提高局部溶液的碱度。随着距离开漏区距离的增加，阴极极化强度的提高对缝隙底部阴极保护水平的要求越来越高。露天度假区与内部裂隙之间总是存在电位差，降低了CP的有效性。(C)2009爱思唯尔有限公司版权所有
In this work, a test rig was developed to study the effect of cathodic protection (CP) on corrosion of X70 pipeline steel in the crevice area under disbonded coating through the measurements of local potential, solution pH and dissolved oxygen concentration. Results demonstrated that, in the early stage of corrosion of steel, CP cannot reach the crevice bottom to protect steel from corrosion due to the geometrical limitation. Corrosion of steel occurs preferentially inside crevice due to a separation of anodic and cathodic reaction with the depletion of dissolved oxygen in the crevice solution. The main role of CP in mitigation of sequential corrosion of steel in crevice under disbonded coating is to enhance the local solution alkalinity. With the increase of distance from the open holiday, a high cathodic polarization is required to achieve appropriate CP level at crevice bottom. A potential difference always exists between the open holiday area and inside crevice, reducing the CP effectiveness. (C) 2009 Elsevier Ltd. All rights reserved