Crevice corrosion of Q235 carbon steels in a solution of NaHCO3 and NaCl

The crevice corrosion of Q235 carbon steels in a solution of NaHCO3 and NaCl was investigated mainly by electrochemical noise. Three stages of crevice corrosion were found and include an induction stage, a transformation stage and a stable development stage. Principal component analysis and hierarchical agglomerative cluster analysis were used to identify the crevice corrosion stages. The electrode area ratio of the outer to the inner part of the crevice (r) significantly influenced the occurrence and development of crevice corrosion. The induction stage time increased as r increased.