Effect of Chloride Ion on Iron Corrosion in NaOH Solution

Abstract

Potentiostatic polarization curves for the system , in which the level of reactable impurities had been reduced to 10−6 ppm, showed that Fe did not corrode and that the Fe behavior was similar to Pt. Introduction of chloride ion changed the potentiostatic polarization behavior and at corrosion occurred. Chloride ion also caused the development of a pronounced active dissolution region in the anodic polarization curves. At 0.2 µg/cc of chloride ion, the changes in the polarization curve were small. At 2 µg/cc of chloride ion a typical pattern had developed which showed a definite corrosion region, followed by “passivity” as the potential was increased. At 2000 µg/cc of chloride ion corrosion was marked, even in the “passive” region.