XPS ANALYSIS OF CO2 CORROSION PRODUCT SCALES ON P110 STEEL UNDER HIGH TEMPERATURE AND PRESSURE

摘要

CO2 corrosion product scales was prepared on P110 steel in carbon dioxide corrosion environment in autoclave, and the surface and cross-section morphology were observed with Scanning Electron Microscope (SEM), and the difference between outer surface and the inner layers in chemical composition was analyzed with X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) adjectively. The results showed that, the main corrosion product in both layers included FeCO3, a little CaCO3 and ferreous oxides, and that the amount of CaCO3 in inner layer, which included a little intermixtures of Fe and Fe3C, was more than that in surface layer, but the amount of the oxides in surface layer was a little more. It was concluded from the difference of Ca 2+ ion between the surface and the inner layers that the inner corrosion scale formed first on the P110 steel in the corrosion process.