X80管线钢在CO32-&HCO3-体系下的电化学腐蚀行为研究

Effect of Different Concentrations of CO and HCO on Electrochemical Corrosion Properties of X80 Pipeline Steel

采用电化学循环极化、正交实验极差分析法,并结合金相显微镜观察腐蚀形貌,研究了CO32-与HCO3-在25组不同配比的质量浓度正交下对X80管线钢电化学腐蚀行为的影响规律。结果表明:由于电极表面电位变化的影响,不饱和溶液中的电化学腐蚀规律可能会受到溶液中电流波动影响,因此CO32-与HCO3-的相互作用规律并非线性规律,当单一离子质量浓度较低时,另一离子会在其质量浓度变化区间存在一个极值点,在该极值点之前腐蚀程度会随离子质量浓度增加而加剧,超过该极值质量浓度后X80钢的腐蚀程度反而会受到抑制;而当此单一离子质量浓度较高时,该极值点会发生变化。经过正交极差计算得出CO32-与HCO3-在模拟土壤环境中的影响因素的主次顺序为:NaHCO3、Na2CO3,即HCO3-在腐蚀体系中的影响比重大于CO32-。

The influences of CO32-and HCO3-on the electrochemical corrosion behavior of X80 pipeline steel under the orthogonality of 25 groups were studied by electrochemical cycle polarization and orthogonal experiment range analysis method,combined with metallographic observation of corrosion morphology.The results showed that due to the potential changes on the electrode surface,the electrochemical corrosion law in unsaturated solutions might be affected by the current fluctuations in the solution,so the interaction between CO32-and HCO3-was non-linear;when the single ion concentration was low,another ion would have an extreme point in its concentration change interval.Before this extreme point,the degree of corrosion would increase with the increase of ion concentration,and the degree of corrosion would be inhibited after exceeding the extreme value;when this single ion concentration was high,the extreme point changed.The orthogonal and range calculations showed that the order of the influencing factors of CO32-and HCO3-in the simulated soil environment was as follows:NaHCO3,Na2CO3,that was,the influence of HCO3-in the corrosion system was greater than that of CO32-.