Role of Acetonitrile on Corrosion of UNS N06022

Abstract Corrosion of UNS N06022 was studied in Acetonitrile - Water - HBr system at 65°C. Experiments were performed in 1.92M HBr concentration, while varying the acetonitrile to water ratio. The water content was varied between 17vol% to 100vol%. In pure aqueous solution, UNS N06022 exhibits an active passive transition. When the water content is decreased to 45vol%, there is evidence of an active passive transition, however, the active dissolution peak occurs at higher current density compared to the case of 100vol% water. However, in 83vol%-17vol% water UNS N06022 exhibits active dissolution and there is no evidence of an active passive transition. The results suggest that water content plays a crucial role in the passivation of the alloy in an Acetonitrile - Water - HBr environment.