Introduction of Cu2+ to the inside of the crevice by chelation and its effect on crevice corrosion of Type 316L stainless steel

Abstract

The chelated complex of Cu2+: [Cu(EDTA)]2− was used to introduce Cu2+ from outside to the inside of crevice. The introduced Cu2+was expected to act as an inhibitor for the crevice corrosion on stainless steels. Crevice corrosion tests confirmed the introduction of Cu2+ to the inside of the crevice via electromigration of [Cu(EDTA)]2−. Migrated [Cu(EDTA)]2− reacted with H+ and inhibited decrease in pH inside the crevice, where Cu2+ was separated from [Cu(EDTA)]2− and suppressed active dissolution of the stainless steel.