The supercritical carbon dioxide cycle power generation system has the advantages of high efficiency

small space occupation and huge water saving

which has broad application prospects. To ensure the long-term safe and efficient operation of this system

the corrosion resistance of high-temperature structural materials is one of the decisive factors. In the experiment

the corrosion behavior and mechanism of the heat-resistant steel T91 was studied on a supercritical carbon dioxide corrosion platform. X-ray diffractometer

scanning electron microscopy and glow discharge spectrometer were used to analyze the type

compositions and distribution of the corrosion products on surface of the heat-resistant steel. The results showed that

the corrosion law of the heat-resistant steel T91 in supercritical carbon dioxide environment followed a parabolic corrosion law

indicating that the corrosion process was controlled by the ion diffusion. The main type of corrosion of heat-resistant steel T91 was general corrosion

and the C-rich products were detected on surface of the corrosion products on T91. The corrosion products on surface of the heat-resistant steel T91 were Fe_3O_4

(Fe

Cr)_3O_4 and carbides

and carbides dispersed in the matrix from the gas-solid interface to the substrate. In the supercritical carbon dioxide environment

carburization phenomenon occurred on the(Fe

Cr)_3O_4 layer and the substrate

indicating that oxidation and carbonation reaction occurred during the corrosion process. The results enriched the evolution law of C element in supercritical carbon dioxide corrosion.