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Assessment of pitting corrosion in bare and passivated (wet scCO 2 ‐induced patination and chemical passivation) hot‐dip galvanized steel samples with SVET, FTIR, and SEM (EDS)
Author(s) -
Saarimaa Ville,
Fuertes Nuria,
Persson Dan,
Zavalis Tommy,
Kaleva Aaretti,
Nikkanen JuhaPekka,
Levänen Erkki,
Heydari Golrokh
Publication year - 2020
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.202011653
Subject(s) - materials science , passivation , galvanization , corrosion , fourier transform infrared spectroscopy , scanning electron microscope , pitting corrosion , metallurgy , zinc , analytical chemistry (journal) , layer (electronics) , composite material , chemical engineering , chemistry , chromatography , engineering
In this study, the local electrochemical activity of untreated and passivated (natural or chemical passivation) zinc specimens was observed during immersion in a 0.1‐M NaCl solution. The localized anodic activity during the exposure, measured with the scanning vibrating electrode technique, was linked to zinc dissolution by the pitting corrosion mechanism. It was correlated to specific corrosion products characterized by Fourier transmission infrared (FTIR) microscopy. FTIR molecule maps were produced from individual pitting corrosion sites (100–200 µm in width). With argon ion beam milling and latest energy‐dispersive X‐ray spectroscopy (EDS) technology, element maps with a high spatial resolution (≪100 nm) were recorded from abrasion‐ and beam‐sensitive corrosion products, showing a residual layer structure. This study demonstrates the capability of FTIR mapping, cross‐section polishing, and state‐of‐the‐art scanning electron microscopy imaging, and EDS element mapping to produce high‐resolution elemental, molecular, and visual information about pitting corrosion mechanisms on a hot‐dip galvanized steel sample.