异种金属管道耦接引起的电位分布研究  

Potential Distributions for Coupling of Disimillar Metallic Pipes in 3.5%NaCl Solution

作　　者：陈日辉 周林[1] 张聪 高新华[2] 周小龙 雍兴跃[1] CHEN Rihui;ZHOU Lin;ZHANG Cong;GAO Xinhua;ZHOU Xiaolong;YONG Xingyue(State-Key Lab. of Organic-Inorganic Composites,Beijing University of Chemical Technology,Beijing 100029,China;Institute No. 701,China Shipbuilding Industry Corporation (CSIC),Wuhan 430064,China)

机构地区：[1]北京化工大学有机无机复合材料国家重点实验室,北京100029 [2]中国船舶重工集团公司第701研究所,武汉430064

出　　处：《腐蚀科学与防护技术》2019年第5期483-488,共6页Corrosion Science and Protection Technology

摘　　要：采用实验与数值模拟计算相结合的方法,研究了异种金属管道耦接条件下在3.5%NaCl溶液中,其管道内表面电位分布规律。结果表明,在静态3.5%NaCl溶液中,当直径为50 mm的碳钢与黄铜管道耦接时,会发生严重的电偶腐蚀。其中,黄铜管道作为阴极受到保护,其受到保护的长度为800 mm;碳钢管道作为阳极,受到加速腐蚀,其腐蚀段长度为260 mm。不管是阴极的保护段还是阳极的腐蚀段,其长度均受浸泡时间、溶液流速及界面状态(如腐蚀产物)的影响。一旦介质流动,碳钢管道腐蚀段长度会降低到240 mm。同时,阴极的保护长度也缩短,且与理论计算结果相差小于5.0%。数值模拟计算与实测结果一致表明,理论公式的计算结果可以用于估算异种金属管道耦合后,电位较负管道腐蚀的长度和电位较正管道受保护的长度。同时,还可以用于管道采用牺牲阳极法进行阴极保护时,确定牺牲阳极保护管道的最大长度。For pipelines of conveying conductive fluids, a relatively active metallic pipe will be subjected to galvanic corrosion when coupled with a relative noble metallic pipe. In such case, many influencing factors may affect the length of the corroded portion of the former pipe. Therefore, the distribution of the inner wall potential along the pipe length for a couple of brass pipe with carbon steel pipe in static 3.5%NaCl solution were assessed by means of electrochemical measurement as well as numerical simulation. Results show that the carbon steel pipe, acting as the anode, was subjected to the accelerated corrosion with a corroded portion of ca 260 mm in length. The brass pipe, acting as the cathode, was protected with a protected portion of ca 800 mm in length. However, in flowing 3.5%NaCl solution, the length of the corroded portion of carbon steel pipe was decreased to 240 mm, and the length of the protected portion of brass pipe was also decreased to 600 mm. It follows that the relative error of the computational simulation with the experimental results was below 5.0%. Therefore, the theoretical formula could be used to estimate the lengths of both the corroded portion and protected portion for the two dissimilar coupled pipes. At the same time, this formula could also be applied for the determination of the maximum length of the protected portion of a pipe, which is subjected to cathodic protection by sacrifice anode.

关 键 词：异种金属管道 电偶腐蚀 电位分布 理论计算 数值模拟 

分 类 号：TG172[金属学及工艺—金属表面处理]