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

Highlights: • μCT and novel algorithms were used to determine the thickness and air-void distribution within the iron carbonate layers. • The μCT results were validated by SEM morphology and mercury intrusion porosimetry (MIP) results. • The relationship between air-void distribution and corrosion behaviour was analysed. • The advantages and limitations of μCT and MIP for the pore characterisation were discussed. 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.