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Electrochemical, surface analytical, and spectroscopic study of passive film and pits formation on food grade ferritic stainless steel AISI‐430 in aqueous acetic acid containing chloride ions
Author(s) -
Mahato Neelima,
Cho Moo Hwan,
Singh M. M.
Publication year - 2018
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201810173
Subject(s) - chloride , materials science , aqueous solution , acetic acid , corrosion , crystallinity , pitting corrosion , electrochemistry , metallurgy , polarization (electrochemistry) , chemistry , electrode , composite material , biochemistry
Pitting corrosion of food grade ferritic stainless steel AISI‐430 was studied in 20% aqueous acetic acid solution containing 0.5 M NaCl. Potentiodynamic polarization measurements at a slow scan rate reveal formation of metastable pits and repassivation. Surface analysis reveals remnants of the passive oxide layer adhered along the circumference of the pits, evidences of loss of microcrystallites, no significant loss in crystallinity during corrosion process and formation of mixed oxides of iron and chromium. The pitting of ferritic steel is an autocatalytic process, and the proposed mechanism suggests that both chloride and acetate ions play important role.