在含硫污染的海洋大气环境中核电用钢的腐蚀行为

Corrosion behaviors of steels in marine atmospheric environment with SO_2 pollution

利用XRD,FTIR和SEM分析技术和电化学测试技术,研究了低合金钢P265GH和碳钢Q235在辽宁省红沿河地区大气暴露不同时间(最长时间为2年)的腐蚀行为.结果显示,这两种钢的腐蚀失重与实验时间的关系均符合幂函数△W=Atn规律,其n值处于0.5～1之间.SO2和Cl-的协同作用使钢的腐蚀加剧,钢表面形成的锈层保护性先随着暴露时间的延长而增强,在24个月后出现逆转现象,保护性降低.低合金钢P265GH的耐蚀性优于碳钢Q235.

X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, and electrochemical analysis techniques were used to study the corrosion products, morphologies, and electrochemical properties of rust layers. The corrosion behaviors of a low-alloy steel, P265GH, and a carbon steel, Q235, exposed to the atmosphere in the Hongyanhe area for up to 24 months were studied. The results show that the corrosion processes can be described using the equation AW=Atn; the dynamic parameter, n, is between 0.5 and 1. During the first 12-month period, the mass losses of the two steels increased at almost constant rates. The overall mass loss of the low-alloy steel P265GH was smaller than that of the carbon steel Q235 for the same exposure time, although it was almost the same during the first three months. The difference between the mass losses of the two steels increased with time; the low-alloy steel P265GH had better corrosion resistance. The synergistic effect of SO2 and CV plays an important role in promoting corrosion of the two steels.