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针对油气管道CO_2腐蚀环境,研究了Cr含量为1%~5%(质量分数)的5种低铬钢的阳极极化行为,讨论了半钝化行为受Cr含量的影响规律。测试了不同pH值下5种低铬钢的极化曲线,探究了不同Cr含量的低铬钢出现明显半钝化的临界pH值。利用Raman光谱,对比了在不同pH值溶液中极化生成的腐蚀膜的成分。结果表明,随着Cr含量的升高,低铬钢半钝化特征变得更加明显。在CO_2环境下,溶液pH值的升高对Cr(OH)_3沉积有利,基体中Cr的溶解导致低铬钢表面生成了Cr(OH)_3膜,在极化曲线测试过程中,显示出半钝化的特征。
According to the CO_2 corrosion environment of oil and gas pipelines, the anodic polarization behavior of five low chromium steels with Cr content of 1% ~ 5% (mass fraction) was studied. The influence of Cr content on the semi - passivation behavior was discussed. The polarization curves of five kinds of low chromium steels at different pH values were tested. The critical pH values of semi-passivated low chromium steels with different Cr contents were investigated. Using Raman spectroscopy, the composition of the corrosion film formed by polarization in different pH solutions was compared. The results show that with the increase of Cr content, the semi-passivation characteristics of low chromium steel become more obvious. Under the CO_2 environment, the increase of pH value of the solution favored the deposition of Cr (OH) 3, and the dissolution of Cr in the matrix resulted in the formation of Cr (OH) 3 film on the surface of low chromium steel. During the polarization curve test, Passivated features.