Chloride induced pitting initiation on 304L stainless steel in acidic sodium sulphate solutions

Author: Sá M. S. De   Rangel C. M.   Sequeira C. A. C.  

Publisher: Maney Publishing

ISSN: 0007-0599

Source: British Corrosion Journal, Vol.23, Iss.3, 1988-01, pp. : 186-189

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Abstract

The kinetics of pit initiation on 304L austenitic stainless steel in aqueous sodium sulphate solutions containing various concentrations of sodium chloride have been investigated by induction time measurements using the potentiostatic test method. Oxide films were grown on the surface of the steel by potentiostatic oxidation in the passive region. Pitting induction time has been found to be dependent on the oxide film thickness: the thicker the oxide film, the longer the induction time. Measurements at temperatures rangingfrom 20 to 80°C gave an apparent activation energy for pitting initiation of ~ 48·1 kJ mol−1, which suggests that the mechanism of single ion transport through the film is the rate determining step.