Influence of the microstructure and alloying element on the polarization behaviour within the crevice of UNS S32304 duplex stainless steel

The influence of microstructure evolution and alloying element redistribution of UNS S32304 duplex stainless steel induced by annealing treatment on the crevice corrosion behaviour was studied. As the annealing temperature was increased from 1030 to 1150 °C, the crevice corrosion resistance was decreased and the active peaks were not only increased in magnitude but also shifted towards the more noble direction. Austenite and ferrite have greatly different polarization behaviour within the crevice. This study provides guidance to the material design and usage in industry field in consideration of different polarization behaviour induced by the evolution of microstructure and alloying elements.

► Crevice corrosion resistance declines as the annealing temperature is increased.
► Polarization behaviour within the crevice is studied in situ.
► A large IR drop and positive shift of active peak result in a low CCT.