The crevice corrosion behaviour of stainless steel in sodium chloride solution

The crevice corrosion behaviour of 13Cr stainless steel in NaCl solution was investigated mainly by electrochemical noise measurements, considering the influences of the crevice opening dimension (a) and the area ratio of the electrode outside the crevice to the one inside the crevice (r). Results show that the increase of r value prolongs the incubation period of crevice corrosion, but crevice corrosion develops rapidly once the crevice corrosion occurs. The crevice corrosion develops preferentially at the crevice bottom and then spreads to the whole electrode surface. Proton could reduce on the uncorroded area and hydrogen bubbles form inside the crevice.

► There are three stages in crevice corrosion of 13Cr stainless steel in NaCl solution. ► The decrease of crevice thickness shortens the incubation period of crevice corrosion. ► The incubation period of crevice corrosion prolongs as the increase of the area ratio. ► Corrosion develops preferentially at crevice bottom and hydrogen reduction occurs inside the crevice. ► Crevice corrosion of 13Cr stainless steel in NaCl solution follows the passive dissolution mechanism.