The Effect of Dissolved Chlorine on the Pitting Behavior of 304L Stainless Steel in a 0.5 N NaCl Solution

Abstract

Abstract Electrochemical experiments were performed on a 304L (UNS S30403) stainless steel alloy in a 0.5 N NaCl solution as a function of chlorine content (0 to 180 mg/L) at room temperature. Experiments performed included a measurement of the corrosion potential as a function of time, the determination of both the breakdown and repassivation potentials using cyclic polarization curves, and the use of a scratching electrode technique to measure the kinetic aspects of the breakdown of passivity. The addition of chlorine to a solution of pH 5 in the concentration range of 20 to 60 ppm chlorine resulted in a significant shift in the corrosion potential in the noble direction. At higher concentrations of chlorine, the corrosion potential shifts back toward that observed without chlorine additions. Chlorine also results in a monotonic shift in the breakdown potential, suggesting that the passive film is rendered more stable against the initiation of localized corrosion. However, the repassivation potential ex...