碳钢在点蚀/缝隙腐蚀闭塞区模拟溶液中的腐蚀行为  

CORROSION BEHAVIOR OF MILD STEEL IN SIMULATED SOLUTIONS WITHIN PITS AND CREVICES

作　　者：赵景茂[1] 左禹[1] 熊金平[1] 

机构地区：[1]北京化工大学材料科学与工程学院,北京100029

出　　处：《中国腐蚀与防护学报》2002年第4期193-197,共5页Journal of Chinese Society For Corrosion and Protection

基　　金：国家重点基础研究项目 (G19990 6 5 0 )

摘　　要：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(Vc)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The corrosion behaviors of mild steel in simulated solutions within pits and crevices were investigated by polarization measurements and EIS.The results showed that the cathodic process was controlled by the diffusion of hydrogen ion at pH 2～4,and controlled by electrochemical process at pH lower 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 corrosion rate was inversely proportional to the pH value.A small change in pH value within pits/crevices would result in a marked change in corrosion rate. The enrichment of Cl - anions within pits/crevices would cause a decrease in pH value.

关 键 词：碳钢 点蚀 缝隙腐蚀 模拟溶液 

分 类 号：TG174.3[金属学及工艺—金属表面处理] TG172.9[金属学及工艺—金属学]