Electrochemical behaviour of N80 steel in CO2 environment at high temperature and pressure conditions

• Published in: Corrosion science Vol. 189; p. 109619
• Main Authors: Ren, Xiedong, Wang, Hu, Wei, Qiang, Lu, Yuan, Xiao, Bowen, Xie, Juan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 15.08.2021; Elsevier BV
• Subjects: A. Carbon steel; Aragonite; B. EIS; B. Polarization; B. SEM; B. XRD; C. Interfaces; Calcium carbonate; Carbon dioxide; Corrosion products; Electrochemical analysis; High strength steels; High temperature; Iron carbonate; Medium carbon steels; Scale formation; Submerging; Substrates; Surface analysis (chemical); B. SEM; A. Carbon steel; B. XRD; C. Interfaces; B. EIS; B. Polarization
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2021.109619

•Pt wire used as reference electrode for electrochemical measurements at high temperature and pressure.•Corrosion rate decreased and the passivation weakened with increase of temperature.•The protectiveness of the scale enhanced with immersion time at all temperatures.•The corrosion rate and precipitation of FeCO3 were inhibited by the formation of CaCO3.•CaCO3 of aragonite formed in 150°C provided better protection to substrate for its compact structure. This study investigates the scale formation behaviour of N80 steel in CO2 environment at different temperatures and immersion time by in-situ electrochemical and surface analysis techniques. It shows that the temperature and immersion time have significant influence on electrochemical behaviour, which is due to the different scales formed on N80 steel surface. The scales formed at 60°C and 90°C are mainly corrosion products. At 120°C and 150°C, the scale consists of CaCO3. The formation of CaCO3 inhibits the corrosion and the formation of FeCO3. CaCO3, formed in 150°C, is aragonite, which provides better protection to substrate for its compact structure.