Q235钢在模拟海水中的缝隙腐蚀

Crevice Corrosion of Q235 Steel in Simulated Seawater

采用丝束电极(WBE)联合电化学阻抗谱(EIS)等方法研究了Q235钢在模拟海水中的缝隙腐蚀行为,并配合离子选择性电极(ISE)传感器对缝隙腐蚀不同阶段的Cl-和H+变化进行观测。结果表明:缝隙腐蚀的发展过程符合氧浓差电池-闭塞电池理论;在缝隙腐蚀的诱发期与扩大期,缝内溶液中H+和Cl-含量增大,缝内溶液成分的极端值分别为pH 2.43,Cl-浓度3.45mol/L;当缝隙腐蚀进入闭塞电池阶段后,腐蚀过程符合Bockris机理,且pH与Cl-浓度保持着较好的线性相关;Q235钢在模拟海水中发生缝隙腐蚀的概率约为73.3%,点蚀率为6.1%。

The crevice corrosion of Q235 steel in simulated seawater was studied using a wire beam electrode（WBE）in combination with electrochemical impedance spectroscopy（EIS）.In addition,iron selective electrodes（ISE）were used as a senser to monitor the concentration change of H＋and Cl^-in different stages of crevice corrosion.The results indicated that the propagation of the crevice corrosion complied with the theory of oxygen concentration cell followed by occluded corrosion cell.The concentration of H＋and Cl^-kept increasing in the initiation and enlargement periods of the crevice corrosion,and the extreme values of the composition of the solution were pH 2.43 and Clconcentration of 3.45 mol·L-1 within the crevice.The corrosion progress complies with Bockris mechanism after the occluded cell began to take control with a good linear correlation between pH and the concentration of Cl^-.The crevice corrosion probability of Q235 steel was statistically estimated to be 73.3%,and the pitting ratio was 6.1%.