AH32长尺试样在模拟海洋潮差区腐蚀行为的电偶电流研究  

Study on the Galvanic Current of Corrosion Behavior for AH32 Long-Scale Specimen in Simulated Tidal Zone

作　　者：赵林[1] 穆鑫[1] 董俊华[1] 伍立坪 王长罡[1] 柯伟[1] 

机构地区：[1]中国科学院金属研究所,沈阳110016

出　　处：《金属学报》2017年第11期1445-1452,共8页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目No.51671200;国家高技术研究发展计划项目No.2015AA034301;国家腐蚀平台基金;中国科学院海洋研究所海洋环境腐蚀与生物污损重点实验室资助项目No.MCKF201611~~

摘　　要：利用自制的模拟实验装置模拟实海潮差,监测了在模拟潮差区内AH32长尺试样的电偶电流和电极电位变化情况。结果表明,由于供氧差异形成的宏电池作用,AH32长尺试样在潮差区和全浸区内的电极电位分布不均衡,引发了内部的电偶电流,其实质为阴、阳极反应产生的净电流。在潮差区内,AH32长尺试样不同部位的电偶电流随潮位运动发生周期性变化;当潮位最高时,所有部位的电偶电流均处于极大值状态,且中间潮位部位的电偶电流最大,由此所引起的阳极电流也最大。根据电偶电流的变化计算出的干燥、润湿和浸没状态的时间分布表明,AH32长尺试样在潮位区不同部位的腐蚀量取决于润湿和浸没时间在该部位的分配。各部位在浸没态时存在宏电池作用,产生电偶电流。而在润湿态下,由于薄液膜的溶液电阻很大,导致宏电池驱动电位几乎等于在薄液膜上的电压降,因此宏电池作用极弱,且不产生电偶电流。润湿时间和润湿电量的关系显示,潮位运动中AH32长尺试样的最大润湿时间出现在平均中潮位以上的部位,表明因润湿引起的该部位的腐蚀失重最大。结合由浸没态引起的平均中潮位腐蚀失重最大的结果可以确定,在潮水涨落过程中AH32长尺试样的最大腐蚀失重量应出现在平均中潮位偏上的部位,这与腐蚀速率的测量结果一致。The environment of the tidal zone is very complex. The interactions of dry-wet alternation and sea erosion lead to serious corrosion of steel structures, which makes it difficult to adopt protective methods. Therefore, it is of great significance to study the corrosion and protection methods of steel in tidal zone. For long-scale steel through the tidal zone and immersion zone, there is a big difference in corrosion behavior with complete immersion condition, the potential of the steel surface changes due to the influence of oxygen concentration difference and tidal fluctuations or other factors. In this study, the galvanic current and open circuit potential of the long-scale AH32 steel were monitored in simulated tidal zone. The results shows that the potential at different tide levels and different immersion depths for a long-scale AH32 specimen is not unified, with the macro cell was formed by the difference of oxygen sup- ply, which caused internal galvanic current. The essence of the galvanic current is the net current that was generated by the sum of anode and cathode current. Galvanic current at different positions on the long-scale AH32 specimen varies with the tidal movement periodically in tidal zone. When tide is at the highest level, the galvanic current of all parts accesses a maximum value, and among these maximum values, the largest one is at the middle part of specimen, which causes the biggest anodic dissolution cur- rent density. According to the variation of the galvanic current, the time distributions of the drying, wetting and immersion states were calculated, and the results showed that the corrosion scale of the long-scale AH32 specimen at different positions depends on the time all location of wetting and immersion in tidal zone. The macro cell caused the galvanic current when all parts of the specimen were immersed. At wet- ting state, the solution resistance of the thin liquid film is very large, which leads to the change of the driv- ing potential of the macro cell into the potential dr

关 键 词：AH32钢 潮差区 长尺试样 电偶电流 电极电位 

分 类 号：TG172.5[金属学及工艺—金属表面处理]