Abstract: Corrosion of oil and gas pipeline steel in the marine environment is one of the important factors that damage the integrity of oil and gas pipelines. The effects of different HCO〖_(3)^-〗 concentrations in simulated ocean solution on the electrochemical corrosion behavior of X100 steel were investigated by using potentiodynamic polarization and AC impedance technique. The results showed that the corrosion current density, the corrosion pits number and area of X100 steel increased with increasing of HCO〖_(3)^-〗 ion concentration. In addition, when HCO〖_(3)^-〗concentration was 0.1 and 0.5 mol/L, transition passivation zone appeared in the anodic polarization curve of X100 steel, and unstable product film was formed on the metal surface.

Key words: X100 pipeline steel, Electrochemical corrosion, Marine environment, Bicarbonate, Potentiodynamic polarization

摘要： 海洋环境中油气管线钢腐蚀是破坏油气管线完整性的重要因素之一。在模拟海洋溶液中，采用动电位极化和交流阻抗技术研究了不同HCO〖_(3)^-〗浓度对X100钢的电化学腐蚀行为影响。结果表明，HCO〖_(3)^-〗浓度在2.5×10-3~0.5 mol/L，随HCO〖_(3)^-〗浓度的升高，X100钢腐蚀电流密度随之增大，且金属表面腐蚀坑的数量和面积不断增加；此外，当HCO〖_(3)^-〗浓度为0.1、0.5 mol/L时，X100钢阳极极化曲线出现了过渡钝化区，金属表面形成了不稳定产物膜。

关键词: X100管线钢, 电化学腐蚀, 海洋环境, HCO〖_(3)^-〗, 动电位极化