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利用极化曲线和阻抗技术 ,对低碳钢在不同pH值H2 S溶液中的腐蚀电化学行为进行了研究。结果表明 ,在溶液pH值较低时 ,腐蚀电极主要受阳极酸性溶解过程控制 ,表面无硫化物沉积 ,其阻抗谱除高频容抗弧外 ,低频有一感抗弧存在 ;随pH的升高 ,腐蚀电位明显负移 ,电流密度减小 ,表面出现硫化物的不连续沉积 ,腐蚀因溶液pH值的增加和硫化物的沉积而减小 ,电极过程主要受硫化物的生长所控制 ;在pH值为 6.2时 ,由于HS 的阴极去极化 ,腐蚀电流增加 ;当pH大于 7后 ,电极表面因氧化膜的生成而呈现钝化特征 ,极化电阻显著增加。基于溶液中HS 同OH 的竞争吸附 ,提出可能的腐蚀历程 ,据此可解释有关实验事实。
The corrosion behavior of low carbon steel in H2S solutions at different pHs was investigated by using polarization curves and impedance techniques. The results show that the corrosion electrode is mainly controlled by anodic dissolution process when the solution pH is low, and there is no sulphide deposition on the surface. In addition to the high frequency capacitive arc, there is an inductive arc in the impedance spectrum. With the increase of pH, corrosion The potential is negatively shifted, the current density is reduced, the discontinuous deposition of sulfide appears on the surface, the corrosion decreases due to the increase of solution pH and the deposition of sulfide, and the electrode process is mainly controlled by the growth of sulfide. 6.2, the corrosion current increased due to the depolarization of HS cathode. When the pH was greater than 7, the surface of the electrode showed passivation due to the formation of oxide film, and the polarization resistance increased significantly. Based on competitive adsorption of HS with OH in solution, a possible corrosion history is proposed, from which experimental facts can be explained.