Determination of thickness and air-void distribution within the iron carbonate layers using X-ray computed tomography

Iron carbonate (FeCO₃) is a common corrosion product reported in oil and gas fields. The growth kinetics and the presence of connected voids within this layer have a significant influence on the protective capability afforded to the steel surface. X-ray micro-computed tomography (μCT) was used in conjunction with novel algorithms to determine the thickness and air-void distribution within the crystalline FeCO₃ layer. Then the relationship between the air-void distribution and corrosion behaviour was analysed. Mercury intrusion porosimetry (MIP) was used to validate the μCT results. The advantages and limitations of both methods for the pore characterisation were discussed.