Crevice and Pitting Corrosion Behavior of Stainless Steels in Seawater

Abstract Pitting and crevice corrosion tests in natural seawater were performed on a series of stainless steels (i.e. S31603, N08904, S32304, S31803, S32520, N08925 and S31266) in order to determine their resistance to these types of localized corrosion. Open circuit potential (OCP) measurements for these alloys show for short exposure times an ennoblement in the OCP. After a certain time, occasional fall and rise in the OCP values was observed, which can be related to nucleation and repassivation of pits and/or crevices on the metal surface. Analysis of the electrochemical behaviour and microscopic observations shows that only S31603 and S32304 alloys were susceptible to crevice and pitting corrosion, whereas the remaining alloys exhibited good resistance. Pitting potentials determined by the potentiodynamic technique also show S31603 and S32304 are susceptible to pitting corrosion under the experimental conditions used in this work.