Localized Corrosion of Mild Steel in a CO2 Aqueous Environment - a Review

Abstract

Localized corrosion is a non-uniform loss of metal from the pipe wall which can lead to a loss of containment. Types of CO2 localized corrosion considered here include: pitting corrosion and so called mesa attack. The most common causes have been grouped into four categories, those related to: flow, chemical causes, metallurgical causes and biological causes. Localized CO2 corrosion mechanisms identified here include loss of protective layer, galvanic coupling, local water chemistry changes and bio-catalytic effects. Loss of protective corrosion product layer or inhibitor film leading to high (bare steel) corrosion rate is the most common mechanism; galvanic coupling between protected and unprotected areas might lead to even higher corrosion rates; often accompanied by local changes of water chemistry which stabilize localized attack propagation and or the bio-catalytic effect.