An AES and SIMS study of the influence of chloride on the passive oxide film on iron

The kinetics of passivation of Fe in pH 8.4 birate buffer solution at 0.0 V have been studied in both the presence and absence of 0.5 M Cl-. Cl- has no influence on the decay of the passive current with time over the course of several hours. Oxide films wer examined by AES and SIMS for possible Cl- incorporation into the oxide lattice. Neither technique was able to detect any Cl- within the film. The same is true even above the pitting potential, which probably indicates that Cl- incorporation into the oxide film is not a precursor to pit initiation. It also appears that Cl- does not cause any film thinning.Peer reviewed: YesNRC publication: Ye