In situ investigation of crevice corrosion on UNS S32101 duplex stainless steel in sodium chloride solution

• Delayed and immediate crevice corrosions are investigated.
• The crevice corrosion morphologies are studied by SEM.
• The relocation of active dissolution region is observed.
• The mechanisms of crevice corrosion are discussed in detail.

The crevice corrosion of UNS S32101 in neutral 0.1 M NaCl solutions at room temperature was investigated directly by a facile method. Experimental results showed that both delayed and immediate crevice corrosion can be initiated. Morphology study indicated that the heaviest corrosion attack happened just below the passive/active boundary on the crevice wall. The relocation of the active dissolution regions during crevice corrosion was observed and explained by established theory. The mechanisms of the delayed and immediate types of crevice corrosion on UNS S32101 duplex stainless steel were discussed.