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This paper contrastsmetastable and stable pitting of 316 austenitic stainless steel in chloride and bromide bearing solutions.Metastable and stable pitting characteristics were evaluated by potentiostatic and potentiodynamic polarization experiments, respectively. Results revealed that for a given concentration of halide anions, pitting and repassivation potentials rise by increasing the Br-:Cl- concentration ratio in the environment. Increasing the relative concentration of Br- also leads to a decrease in the values of metastable pit stability product. Furthermore, higher concentration of bromide in the solution reduces the growth kinetics of metastable pits. Using pencil electrodes, itwas also found that hindrance of the dissolution reactions in presence of bromide anion could be responsible for the lower aggressivity of bromide and the observed decrement in metastable growth kinetics. [ABSTRACT FROM AUTHOR]

In this research, pitting corrosion of martensitic stainless steel in presence of halide anions was investigated by using polarization techniques. Results confirm that the aggressivity of halides increases in the following order: I − < Br − < Cl − . Although fluoride does not offer any pitting by itself, its presence together with chloride increases the occurrence frequency of metastable pits and pitting potential, simultaneously. While the pitting was more probable in NaCl solution, its metastable stability product was observed equal or even less than other solutions. [ABSTRACT FROM AUTHOR]