【摘要】 利用高温高压釜对N80钢进行了两种温度、不同CO2分压下的腐蚀实验.测量了腐蚀速率,观察了腐蚀产物膜的宏观形貌及去除腐蚀产物膜后金属基体的表面状态,用扫描电镜(SEM)观察了腐蚀产物膜的微观形貌并测量了膜的厚度,对在不同条件下成膜的N80钢进行了电化学极化曲线与交流阻抗谱(EIS)分析.结果表明CO2分压升高,腐蚀产物膜保护性能提高,但由于介质的腐蚀性增强,腐蚀速率上升;膜局部缺陷是导致金属基体表面点蚀的主要诱因,CO2分压升高有利于减少65℃时膜表面的局部缺陷;在90℃下腐蚀产物膜的保护性能比65℃下对CO2分压的变化更为敏感.更多还原

【Abstract】 Corrosion tests of N80 steel under different CO2 partial pressures at 65 ℃ and 90 ℃ were carried out by a self-made high-temperature high-pressure autoclave. The mass losses of the steel under different CO2 partial pressures were measured. The morphologies of the corrosion scale and the descaled N80 steel were observed by SEM, and the thickness of the scale was measured. Electrochemical polarization curve and impedance spectroscopy analysis (EIS) were employed to study the corrosion behavior of N80 pre-corroded under different CO2 partial pressures at two temperatures. The results show that as the CO2 partial pressure increases, the protection property of the scale becomes better, but the corrosion rate increases because of the increase in solution corrosivity. The local defects of the corrosion scale are responsible for the pitting corrosion of metal matrix, the increase in CO2 partial pressure makes for reducing the defects. Compared with 65 ℃, the protection property of the corrosion scale is more sensitive to the change of CO2 partial pressure at 90 ℃.更多还原