Role of conductive corrosion products on the protectiveness of corrosion layers
- Elf Aquitaine Production, Pau (France)
- Inst. for Energiteknikk, Kjeller (Norway)
In the CO{sub 2} corrosion of steels, the bicarbonate ion HCO{sub 3}{sup {minus}} is simultaneously the buffer for carbonic acid, the source of FeCO{sub 3} precipitation and the product of the cathodic reaction. In addition to the spatial separation of the production of Fe{sup ++} and HCO{sub 3}{sup {minus}}, the galvanic coupling between the steel and cementite layers is also the principal cause of internal acidification in these layers, since the HCO{sub 3}{sup {minus}} ions are then removed from the steel surface by electromigration. This can facilitate the initiation of localized corrosion, by lateral galvanic coupling. This mechanism also explains the role of traces of free acetic acid and the existence of multiple steady states. Finally, transposition to the corrosion of iron by H{sub 2}S or to the corrosion of copper is also discussed.
- OSTI ID:
- 268159
- Report Number(s):
- CONF-960389-; TRN: IM9634%%231
- Resource Relation:
- Conference: National Association of Corrosion Engineers (NACE) annual corrosion conference and exposition: water and waste water industries, Denver, CO (United States), 24-29 Mar 1996; Other Information: PBD: 1996; Related Information: Is Part Of Corrosion/96 conference papers; PB: [6615] p.
- Country of Publication:
- United States
- Language:
- English
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