Localized CO2 corrosion propagation at moderate FeCO3 supersaturation initiated by mechanical removal of corrosion scale

The propagation of localized CO₂ corrosion was investigated at moderate iron carbonate supersaturation using an artificial defect method with re-formed corrosion scale. A mechanical tool was developed which locally removed pre-formed iron carbonate scale and initiated localized corrosion at a FeCO₃ supersaturation of 3–10. The localized corrosion rate was calculated based on electrochemical measurement using a simplified algorithm and was also measured at the deepest part of the defect using scanning electron microscopy. Localized corrosion was driven by a galvanic cell established between the two surfaces exposed in the artificial defect where an open circuit potential difference was maintained.