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 o/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.
Predicting carbon dioxide corrosion of bare steel under an aqueous boundary layer with oxygen and cathodic protection
Vorhersage der Kohlendioxidkorrosion von ungeschütztem Stahl unter einer wässrigen Grenzschicht mit Sauerstoff und kathodischem Schutz
Corrosion, Houston ; 60 , 9 ; 845-851
2004
7 Seiten, 10 Bilder, 11 Quellen
Aufsatz (Zeitschrift)
Englisch
Predicting carbon dioxide corrosion of bare steel under an aqueous boundary layer
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