Electrochemical Studies of the Passive Film on 316 Stainless Steel in Chloride Media

The kinetics of passive film growth on 316 stainless steel in 3% sodium chloride solution have been studied by dc and ac electrochemical measurements. The inverse logarithmic rates of current decay showed two stages of film growth, both controlled by a high field conduction mechanism. Impedance measurements were interpreted on the basis that diffusion of the metallic species through the film controlled the film growth‐dissolution process. Capacitance data indicate that the film is 20–25Å thick, depending on potential, with a field strength of .