Q235碳钢在静止和流动条件下的腐蚀不均匀性研究

目的研究Q235碳钢在静止和流动条件下腐蚀程度和主要腐蚀区域的差异。方法使用丝束电极(WBE)技术和电化学阻抗谱(EIS)技术分别研究了WBE在静止和流动条件下的电流密度分布、电荷转移电阻以及腐蚀形貌的变化和差异,同时分析了电极的极性转换现象。结果流动条件下Q235碳钢的电荷转移电阻明显降低。在静止条件下,Q235碳钢表面阳极电流区域所占的最大比例为47%,且阳极电流峰集中出现在WBE的中间区域,而四周边缘处的阳极电流峰较少。在流动条件下,Q235碳钢表面的阳极电流区域所占的最大比例为58%,阳极电流峰随机分布在整个WBE表面,且电流分布区间明显变窄。浸泡在静止条件下的58~#电极和流动条件下的39~#电极发生了多次极性转换现象。结论 Q235碳钢在静止和流动条件下均发生了明显的不均匀腐蚀现象。流动条件加剧了Q235碳钢的腐蚀且降低了腐蚀不均匀性。静止条件下Q235碳钢的腐蚀区域集中在中间区域,流动条件下Q235碳钢的腐蚀区域随机分布在整个碳钢表面。静止和流动条件下的钢电极均发生了电流的极性转换现象。

Corrosion Inhomogeneities of Q235 Carbon Steel under Static and Flowing Conditions

The work aims to study the difference of corrosion degree and main corrosion areas of Q235 carbon steel under static and flowing conditions. The changes and difference of current density distributions, charge transfer resistance and surface morphology of Q235 carbon steel were studied by WBE and EIS techniques. Meanwhile, the polarity reversals of the electrode were also analyzed. The charge transfer resistance of Q235 carbon steel under flowing conditions was reduced. Under static conditions, the maximum proportion of the anodic current area on the carbon steel surface was 47%, and the anodic current peaks were concentrated in the middle of the WBE and fewer anodic current peaks appeared at the edge of WBE. Under flowing conditions, the maximum proportion of the anodic current area on the carbon steel surface was 58%, and the anodic current peaks were randomly distributed across the WBE surface and the interval of current distributions was significantly narrowed. Polarity reversals occurred in No.58 and No.39 electrodes, which were respectively immersed in static and flowing conditions. In conclusion, the nonuniform corrosion of Q235 carbon steel could be found under both static and flowing conditions. Thecorrosion degree of Q235 carbon steel became more seriousand the corrosion inhomogeneities were reduced under flowing conditions. Under the static condition, the corrosion area of Q235 carbon steel was concentrated in the middle area, while the corrosion area of Q235 carbon steel under flowing condition was randomly distributed on the entire carbon steel surface. The reasons for polarity reversals were differentfrom each other. The polarity reversal of current occurred in steel electrodes under both static and flowing conditions.