CORROSION BEHAVIOR OF AUSTENITIC STEELS IN SUPERCRITICAL CO2 POWER GENERATION SYSTEM

The power generation system with supercritical carbon dioxide（SCO2）as the working medium is a prospect technology in the field of concentration solar power. To investigate the corrosion behavior of typical materials in supercritical carbon dioxide power generation system，the corrosion experiment of austenitic steel samples of 316L and 321 exposed in SCO2 atmosphere at the temperature of 550 ℃ and the pressure of 25 MPa for 2000 h was conducted. The experimental results show that oxidation corrosion occurred in austenitic steel samples and 321 exhibits better corrosion resistance than 316L. The corrosion kinetics approximately follows a parabolic law. Both 321 and 316L forms a double oxide layer with chrome-rich scale and manganese chrome-spinel on the inside and iron-rich oxide nodules on the outside. In addition，carbon is mainly deposited on the surface of corrosion products while no carburizing phenomenon is found inside the material. Meanwhile，the corrosion mechanism model of austenitic steels is fabricated. © 2024 Science Press. All rights reserved.