研究了低碳钢在点蚀孔/缝隙腐蚀闭塞区模拟溶液中的腐蚀 行为.结果表明低碳钢在pH等于2～4的模拟闭塞区溶液中，阴极过程由氢离子的扩散步骤控 制，阴极去极化起着主要作用.当pH值小于2时，阴极过程表现为活化特征.阳极溶解过程遵 循着Bockris机理.碳钢在闭塞区的腐蚀不存在临界pH值和临界Cl-浓度，腐蚀速度(V c)的对数与pH值呈线性关系.闭塞区内溶液pH的微小变化，对腐蚀速度有明显的影响.外部 溶液中的Cl-离子迁入闭塞区后，会促使溶液pH下降.
The corrosion behaviors of mild steel in simulated solutions within pits and crevices were investigated by polarization measurement s an d EIS.The results showed that the cathodic process was controlled by the diffusi on of hydrogen ion at pH 2～4,and controlled by electrochemical process at pH lo wer than 2.The anodic dissolution took place by Bockris mechanism.A critical pH value or salt concentration was not observed for mild steel.The logarithm of cor rosion rate was inversely proportional to the pH value.A small change in pH valu e within pits/crevices would result in a marked change in corrosion rate. The en richment of Cl- anions within pits/crevices would cause a decrease in pH value .
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