Electrochemical properties of iron dissolution in the presence of CO{sub 2} -- Basics revisited
- Inst. for Energiteknikk, Kjeller (Norway)
- Elf Aquitaine, Pau (France)
- Univ. of Belgrade (Yugoslavia). Faculty of Technology and Metallurgy
In order to shed more light on the anodic reaction mechanism in CO{sub 2} corrosion of mild steel, two different kinds of electrochemical measurements were used: potentiodynamic sweep and galvanostatic measurements. Experiments were conducted in a glass cell at room temperature (T = 22 {+-} 1 C), different CO{sub 2} partial pressures (0--1 bar), over a broad pH range (2--7) using a rotating cylinder at 4,000 rpm. Distinct and different anodic mechanisms were observed for pH < 4 and for pH > 5. In the intermediate area there seems to be a transition from one mechanism to another. New orders of reaction and Tafel slopes were extracted, very different from what was previously assumed. A coherent ensemble of mechanisms was proposed for the anodic reaction which is consistent with the experimental results. Consequences of the present findings for the CO{sub 2} corrosion area are discussed. For example, in the case of undissolved iron carbide layers, it is no longer possible to discriminate the roles of galvanic coupling and internal acidification.
- OSTI ID:
- 268158
- Report Number(s):
- CONF-960389--
- Country of Publication:
- United States
- Language:
- English
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