Carbon dioxide (CO2) corrosion of bare steel under an aerated aqueous boundary layer with imposed cathodic protection (CP) was modeled. The results show that an imposed CP current decreases the corrosion rate because it changes the steel potential to a more negative value while consuming the oxygen diffusing to the pipe surface as well as the hydrogen ions that dissociate from carbonic acid (H2CO3). This decrease of corrosion rate is greatest near the free corrosion potential and becomes less as the potential is shifted to a more negative value. This change of corrosion rate with the steel potential follows the Tafel relationship between them. At very negative potentials, the reduction of hydrogen ions and H2CO3 to hydrogen is increased and may lead to hydrogen-induced cracking.
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1 September 2004
Research Article|
September 01 2004
Predicting Carbon Dioxide Corrosion of Bare Steel Under an Aqueous Boundary Layer with Oxygen and Cathodic Protection Available to Purchase
F.M. Song;
F.M. Song
‡
*Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON,
Canada
M5S 3E5. Present address: Mechanical and Materials Engineering Division, South-west Research Institute, 6220 Culebra Road, San Antonio, TX 78238.‡Corresponding author. E-mail: [email protected].
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D.W. Kirk;
D.W. Kirk
**Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON,
Canada
M5S 3E5.
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J. W. Graydon;
J. W. Graydon
**Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON,
Canada
M5S 3E5.
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D. E. Cormack
D. E. Cormack
**Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON,
Canada
M5S 3E5.
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‡Corresponding author. E-mail: [email protected].
Online ISSN: 1938-159X
Print ISSN: 0010-9312
NACE International
2004
CORROSION (2004) 60 (9): 845–851.
Citation
F.M. Song, D.W. Kirk, J. W. Graydon, D. E. Cormack; Predicting Carbon Dioxide Corrosion of Bare Steel Under an Aqueous Boundary Layer with Oxygen and Cathodic Protection. CORROSION 1 September 2004; 60 (9): 845–851. https://doi.org/10.5006/1.3287866
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