摘要
目的研究对比了3种不同配方Al-Zn-In合金阳极在南海环境条件下的腐蚀形貌及电化学容量、电化学效率等性能参数,为深海工程装备的阴极防护设计提供可靠的参考依据。方法通过在我国南海1200 m深海试验架上搭载阳极阴极保护测试装置及数据采集、存储系统,采用自放电测试(Free Running Test,FRT)试验方法研究了阳极在110 d长周期条件下的电化学性能,采用超景深三维显微镜对其表面腐蚀形貌进行了观测。结果1#—3#阳极下水后工作电位均快速活化,整个试验阶段,平均工作电位分别为-1.029、-1.033、-1.098 V(Ag/AgCl/海水);电化学效率分别为81.62%、78.02%、87.90%。仅自主设计的3#配方阳极的开路电位和电化学效率达到了UNE-EN 12496-2013阴极保护设计标准的要求。结论与模拟深海环境下的恒电流测试(Galvanostatic Test,GST)短期试验(4 d)结果相比,同一配方阳极在深海110 d长周期FRT测试条件下的电化学效率分别降低15.13%,18.87%和8.14%。长周期FRT试验更接近实际阳极服役状态,可为深海阴极保护设计参数选择提供可靠性参考。相较于1#和2#阳极,3#阳极In元素增加了1倍,使得工作电位更负,溶解区域晶粒细化,电化学效率更高。但是3#阳极表面却发现了局部未溶解区域。可见,仅通过增加In含量对于改善铝合金表面腐蚀形貌效果有限。
Sacrificial anode cathodic protection is one of the most important corrosion protection methods for deep-water steel structures.The electrochemical performance of sacrificial anode in deep-water environment directly affects the protection effect and service life of the facilities.By means of the cathodic protection test device and data acquisition/storage system installed on the 1200 m Deepwater test rack in the South China Sea,the free Running Test(FRT)was applied to study the electrochemical performance of sacrificial anode under the 110 days cycle condition.Solution morphology,electrochemical capacity,current efficiency and other performance of 3 kinds of composition Al-Zn-In-based sacrificial anodes were compared under the environmental conditions in the South China Sea,providing a reliable reference for the cathodic protection design of deepwater subsea engineering facilities.It was found that the working potentials of all sacrificial anodes were activated rapidly,and the average working potentials were-1.029 V(Ag/AgCl/seawater,the same below),-1.033 V and-1.098 V,and the electrochemical efficiencies were 81.62%,78.02%,87.90%respectively.The open circuit potential(OCP)and electrochemical efficiency of the No.3#sacrificial anode met the cathodic protection design of UNE-EN 12496-2013 standard.Compared with the short-term Galvanostatic Test(GST)in a simulated deep water environment,the electrochemical efficiency of sacrificial anodes with the same composition has been reduced by 15.13%,18.87%and 8.14%in the 110-days cycle FRT respectively.The long-period FRT is closer to the anode actual service condition,which could provide reliable reference for the cathodic protection design parameters of deep water.Compared with the No.1#and 2#sacrificial anode,the In element content of the No.3#anode was doubled,resulting in a more negative working potential,grain refinement in the dissolved region and higher electrochemical efficiency.However,local undissolved areas were found on the surface of the No.3#anode.The results
作者
张国庆
张伟
钱思成
于萱
ZHANG Guo-qing;ZHANG Wei;QIAN Si-cheng;YU Xuan(Offshore Oil Engineering Co.,Ltd.,Tianjin 300450,China;School of Chemical Engineering and Technology,Sun Yat-sen University,Guangdong Zhuhai 519000,China;Southern Ocean Science and EngineeringGuangdong Laboratory(Zhuhai),Guangdong Zhuhai 519000,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2022年第5期177-185,共9页
Surface Technology
基金
中国海洋石油集团有限公司的陵水17-2气田开发工程项目(18ZB-DD03)
国产阳极深水应用研究项目(CNOOC-05-GC00GC2016-03)
国家科技基础资源调查专项(2019FY101400)。
关键词
海工装备
深海腐蚀
阴极保护
牺牲阳极
电化学性能
Al-Zn-In合金
off shore facility
deep-water corrosion
cathodic protection
sacrificial anode
electrochemical performance
Al-Zn-In alloy
