铁素体不锈钢在盐酸溶液中的腐蚀过程

利用电化学工作站,结合微观腐蚀形貌分析,研究了铁素体不锈钢在盐酸溶液中的腐蚀过程.结果表明:铁素体不锈钢在盐酸溶液中的腐蚀过程分为3个阶段:表面钝化膜的穿透、腐蚀产物膜的增厚以及阴阳极反应平衡.不锈钢在表面钝化膜的穿透和腐蚀产物膜的增厚阶段仅发生均匀腐蚀,而在反应平衡阶段不锈钢表面出现大量的晶间腐蚀和少量的点蚀.当盐酸质量分数大于10%时,铁素体不锈钢在盐酸溶液中的极化曲线钝化区完全消失,其腐蚀过程主要受阳极控制.随着盐酸质量分数的增大,溶液电阻Rs和电极反应的电荷转移电阻Rt均逐渐减小,同时腐蚀电极表面双电层结构中的充放电能力不发生改变.

Corrosion Process of Ferritic Stainless Steel in Hydrochloric Acid Solution

The corrosion process of ferritic stainless steel in hydrochloric acid solution was researched by electrochemical workstation and microstructure analysis. The results showed that the corrosion process of ferritic stainless steel in hydrochloric acid solution includes three periods: penetrating of ions into the passive film， thickening of corrosion production film and equilibrium of polarizing reactions. Uniform corrosion is the only way found in the periods of penetrating the passive film and thickening of corrosion production film， while abundant intercrystalline corrosion and a few pitting corrosions appear in the period of equilibrium of polarizing reactions. When the hydrochloric acid is above 10%， the corrosion process is completely controlled by the anodic reactions and the passive zone totally disappeared. Both the solution resistance R_s and the charge-transfer resistance R_t decrease with the increase of the concentration of hydrochloric acid， meanwhile the capacities of charging and discharging of the electric double layer in the surface of the stainless steel anode do not change obviously.