文献类型：期刊文献

英文题名：Vertical galvanic corrosion of pipeline steel in simulated marine thermocline

作者：Deng, Peichang[1];Li, Ziyun[2];Li, Xiaogang[3];Hu, Jiezhen[2,3];Wang, Gui[2]

机构：[1]Ocean Univ Guangdong, Coll Chem & Environm, Zhanjiang 524088, Peoples R China;[2]Ocean Univ Guangdong, Coll Mech & Power Engn, Zhanjiang 524088, Peoples R China;[3]Univ Sci & Technol Beijing, Corros & Protect Ctr, Beijing 100083, Peoples R China

年份：2020

卷号：217

外文期刊名：OCEAN ENGINEERING

收录：SCI-EXPANDED(收录号：WOS:000597316900004)、、EI(收录号：20203809185012)、Scopus(收录号：2-s2.0-85090709152)、WOS

基金：The authors were sincerely grateful for the financial support from Natural Science Foundation of China (No. 51801033), National Basic Research Program of China (973 Program) (No. 2014CB643300), and Science and Technology Projects of Guangdong Province China (No. 2016A020225004).

语种：英文

外文关键词：Galvanic corrosion; Simulated marine thermocline; Pipeline steel; Dissolved oxygen; Exploitation of ocean resource

外文摘要：The dramatic changes of temperatures, pH values, dissolved oxygen contents, and nutrients typically occur in marine thermocline, which are the key factors giving rise to the corrosion of metals. Exploitation of offshore oil and gas has made marine metals gradually moving into deep sea and increased their penetration into the marine thermocline. This study investigates the corrosion of X70 pipeline steel in marine thermocline by simulating seawater thermocline identical to the formation mechanism of marine thermocline. Specifically, the corrosion of X70 pipeline steel was analyzed by means of wire beam electrode (WBE) technique, linear polarization (LP), corrosion morphology, and weight loss measurement. Results indicated that the steel's galvanic currents increased with experimental time, and the galvanic corrosion got worse vertically from the top to the bottom of the marine thermocline simulator. Corrosion on the upper part of the long steel was due to the temperature and dissolved oxygen in the upper thermocline regime, and on the lower part primarily due to the galvanic corrosion in the lower regime. The corrosion products of X70 pipeline steel were high-valence iron compounds for the high content of dissolved oxygen in upper thermocline layer, but low-valence iron compounds in the anoxic middle and lower layers. The rusts were composed of two layers, namely, a fluffy outer layer with poor adhesion and a thin inner layer with strong adhesion. The inner layer rust of the X70 pipeline was covering a smaller steel area in the lower part of the thermocline for the anodic activation of galvanic corrosion.