• PROCESS AND PRODUCT TECHNOLOGY • 上一篇 下一篇
胡钢a; 许淳淳b
HU Gang; XU Chunchun
摘要: The electrochemical behavior of X70 pipeline steel in (0.5 mol·L^-1 Na2CO3+lmol·L^-1 NaHCO3) solution was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to analyze the composition and microstructure of the surface film. The results showed that there were two anodic peaks at -600 mV and -350 inV.The surface film formed at -600 mV mainly consisted of ferrous carbonates and ferrous hydroxycarbonates. It had a small reaction resistance. It was metastable and possessed poor p
rotective property. Numerous pits and microcracks existed on the film, which could be the active paths for the initiation of stress corrosion cracking. The surface film formed at -350 mV, mainly consisted of ferric oxides. It has high reaction resistance and offered good protection for the substrate.