1989 年 38 巻 434 号 p. 1341-1345
The electrochemical study for CO2 corrosion was carried out on various chromium steels under high temperature and pressure. The results are as follows. The corrosion potentials in the CO2 solution were about 0.2V higher than those in deaerated solution. Passivity was not observed in the anodic polarization curves for carbon and low Cr content steels.
FeCO3 films were formed on the surface in the CO2 solution under 100°C, but above 150°C, Fe3O4 and Fe2O3 films were formed in deaerated and CO2 solutions, respectively, for low Cr steels. NiO and Cr2O3 films were observed on the surface in high Ni and Cr steels at high temperature.
The contribution of an alloying element for the CO2 corrosion increased with increasing chromium content.