高氯环境中饱和CO_2对13Cr油管钢腐蚀行为的影响

Effect of Saturated CO_2 on Corrosion Behavior of 13Cr Pipe Steel in High Chloride Environment

采用电化学阻抗(EIS)、极化曲线、电化学噪声(EN)和扫描电子显微镜(SEM)研究了高氯环境中饱和CO2对13Cr油管钢腐蚀行为的影响。结果表明:饱和CO2加速材料的腐蚀,增大了腐蚀的发生频率,使材料的腐蚀由点蚀转变为均匀腐蚀。碳酸对钝化膜的去羟基化作用和增大钝化膜的导通率,是材料腐蚀行为变化的原因。

The effect of saturated CO2 on corrosion behavior of 13Cr pipe steel in high concentration chloride environment was studied by EIS, polarization test, EN test and SEM. The results indicated that the corrosion rate and corrosion probability of 13Cr pipe steel were accelerated in high chloride environment with the presence of saturated CO2. The 13Cr pipe steel suffered from pitting corrosion in high chloride concentration environment, whilst, from uniform corrosion by the synergistic effect of CI and CO2. The stability of the passive film of 13Cr pipe steel decreased in high concentration chloride environment with saturated CO2, which can be explained by the dehydroxylation of the outer part of the passive film by carbonic acid and the increase of ionic conductivity of the passive film in aqueous electrolytes.