Long-term Potentiostatic Exposures of 304 Stainless Steel at Elevated Temperatures

Abstract

Stainless steels suffer from pitting and crevice corrosion in chloride environments. This localized corrosion can be prevented by determining a protection potential below which metals will not corrode by pitting or crevice corrosion. Above this potential, crevice corrosion will occur, but pitting will not initiate until the rupture potential is reached. The purpose of this experiment was to determine the protection potential of 304 stainless steel at elevated temperatures using two electrochemical techniques. The electrochemical hysteresis technique, which involves a reverse potentiodynamic scan in the active direction, was first used to identify the protection potential. The protection potential was then verified by long-term immersion of samples in different environments at fixed potentials 50 mV below or above the potentiodynamically-determined value.