The pitting corrosion behavior of the austenitic stainless steel in aqueous
chloride solution was investigated using electrochemical technique.
Corrosion potential (Ecorr) measurement, potentiodynamic experiments,
potential-hold experiments in the passive range, and microscopic examination
were used for the evaluation of corrosion characteristics. The experimental
parameters were chloride ion concentration, immersion time and anodic-hold
potential. Ecorr measurements along with microscopic examinations suggest
that in or above 3.5 % NaCl at pH 2 pitting took place on the surface in
absence of applied potential after 6 hour immersion. The potentiodynamic
experiment reveals that Ecorr and pitting potential (Epit) decreased and
current density in the passive region increased with the increase of
chloride ion concentrations. A linear relationship between Epit and chloride
ion concentrations was found in this investigation. The analysis of the
results suggests that six chloride ions are involved for the dissolution of
iron ion in the pitting corrosion process of austenitic stainless steel.