Effects of solution environments under disbonded coatings on the corrosion behaviors of X70 pipeline steel in acidic soils

作     者：Xu Chen Cui-wei Du Xiao-gang Li Chuan He Ping Liang Lin Lu 

作者机构：School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China School of Storage and Architecture Engineering Liaoning Shihua University Fushun 113001 China 

出 版 物：《International Journal of Minerals,Metallurgy and Materials》 (矿物冶金与材料学报（英文版）)

年 卷 期：2009年第16卷第5期

页      面：525-533页

核心收录：

学科分类：0820[工学-石油与天然气工程] 080706[工学-化工过程机械] 081704[工学-应用化学] 08[工学] 0817[工学-化学工程与技术] 0807[工学-动力工程及工程热物理] 082003[工学-油气储运工程] 

基　　金：supported by the National Science & Technology Infrastructure Development Program of China (No.2005DKA10400) 

主　　题：pipeline steel polarization cathodic protection crevice corrosion 

摘      要：A rectangle crevice assembly was used to study the effects of cathodic protection （CP） potential, crevice thickness, holiday size, bubbling CO2, and surface condition on the chemical and electrochemical environment of the local solution under disbonded coatings. It is found that the cathodic protection removes dissolved oxygen from the crevice and thus shifts the solution to a more al- kaline state. Furthermore, the potential of the steel reaches the protected potential range. The available protection distance increases with the negative applying potential. The steady potential and pH distribution are easily achieved, but the polarization degree is not satisfied within the thinner crevice. The difference in the solution environment is found to correlate to the holiday size. The smaller the holiday, the smaller the difference is. The presence of CO2 inhibits the formation of an alkaline environment. It is also found that the rust layer dramatically decreases the polarization rate in the crevice.