A comparative study on the critical pitting criteria of a super ferritic stainless steel at different temperatures in chloride or bromide solution

Critical pitting criteria of S44660 are investigated in chloride or bromide solution. The more aggressive Cl- does not lead to lower Eb values in all temperature ranges. The Eb-T curves reveal that the pitting behavior with temperature can be divided into transpassivation, transition, and pitting region. The transition region, in which pitting is induced by transpassivation, is verified by potentiostatic tests. The much wider transition region in bromide solution is attributed to the weakened repassivation ability caused by the interaction between Br- and Mo, which indicates that pitting is more prone to occur in bromide solution at a lower temperature.

Automated summary

The critical pitting criteria of S44660 in chloride or bromide solution were investigated. The study found that the more aggressive Cl- does not necessarily lead to lower Eb values in all temperature ranges. The Eb-T curves revealed that the pitting behavior can be divided into transpassivation, transition, and pitting regions with temperature. Further investigations showed that the wider transition region in bromide solution is due to the weakened repassivation ability caused by the interaction between Br- and Mo, indicating that pitting is more likely to occur at lower temperatures in bromide solution.