High-temperature corrosion behavior of structural materials in supercritical carbon dioxide

Supercritical carbon dioxide (S-CO₂) power cycles have emerged as a promising technology for next-generation energy systems due to their high thermal efficiency and compact system design. However, the extreme operating conditions (typically > 550 °C and 15–32 MPa) pose significant challenges for the structural materials in these energy systems, primarily due to the high-temperature corrosion. This review provides a comprehensive overview of the corrosion behaviors of structural materials in S-CO₂ environments, with a particular focus on the key factors influencing the degradation behaviors. Corrosion mechanisms, including oxidation, carburization and their synergistic interactions, are analyzed in relation to operating temperature and pressure, second phase characteristics and environmental impurities such as H₂O, O₂, and SO₂. Special attention is given to the role of second phases (carbides, oxides and intermetallic compounds) in governing microstructural stability and corrosion resistance in high-temperature S-CO₂ environments. In addition, future research directions are proposed, emphasizing the importance of advanced characterization, multi-impurity modeling and second-phase engineering strategies. This work aims to inform the design of advanced structural materials and environmental control strategies for high-temperature S-CO₂ energy systems.