Intragranular corrosion behavior of 310S austenitic stainless steel in supercritical carbon dioxide environments

The corrosion resistance of 310S austenitic stainless steel in supercritical carbon dioxide (S–CO 2 ) at 500 °C and 25 MPa was evaluated for potential use in small modular reactors (SMRs). Over 3200 h, 310S demonstrated excellent durability, with minimal corrosion-induced weight gain of 0.0490 mg/cm 2 . Combined with multi-scale characterization methods (GIXRD, SEM, EDS, TEM, SAED), it was found that increasing exposure time led to a notable rise in surface roughness, from 0.0102 μm to 0.4968 μm, due to Fe 3 O 4 particle formation and intragranular oxidation, resulting in a distinct dual-layered oxide structure with an inner FeCr 2 O 4 layer. A continuous SiO 2 interface layer, along with a ∼50 nm amorphous carbon layer, effectively prevented carburization within the substrate. These findings highlight 310S stainless steel's suitability for high-temperature S–CO 2 applications, offering a promising candidate material for SMR systems where oxidation and carburization resistance are essential.