超级13Cr钢在不同温度NaCl溶液中的膜层电特性与腐蚀行为*

采用全浸泡腐蚀实验方法和扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)、失重法、极化曲线、交流阻抗等分析手段,对超级13Cr油管钢在不同温度NaCl溶液中的腐蚀速率、腐蚀形貌、腐蚀产物及其膜层的电性能进行了分析,研究了溶液温度对其膜层电性能和腐蚀行为的影响。结果显示:超级13Cr油管钢在温度低于80℃的NaCl溶液中具有较好的耐腐蚀性,其表面膜层具有钝化特性,温度对其腐蚀有一定程度的影响,随溶液温度的升高,钝化膜层对基体的保护作用降低,其抗腐蚀性能降低,发生腐蚀的倾向性增大,当溶液温度高于60℃时尤为显著。超级13Cr在不同温度NaCl溶液中由点蚀引发了局部腐蚀,进而导致了全面腐蚀的发生,其腐蚀产物均由Fe和Cr的氧化物组成,且表面的腐蚀产物疏松不致密。

Films Electrochemical Characteristic and Corrosion Behaviors of Super 13Cr Tubing Steels in NaCl Solution at Different Temperature

The corrosion behaviors of super 13Cr tubing steels were investigated by immersion corrosion test in NaCl solution from 20 ℃ to 80 ℃.The corrosion rate,corrosion morphologies,corrosion products and electric characteristics of surface films were analyzed by scanning electron microscopy(SEM),energy dispersive analysis(EDS),X-ray Diffraction(XRD),weight loss,polarization and electrochemical impedance spectroscopy(EIS).The results shows that super 13Cr tubing steels has better general corrosion resistance properties in NaCl solution under 80 ℃,and the surface films has passive characteristics.The temperature of solution has influences on the corrosion of super 13Cr tubing steels in NaCl solutions in a certain degree.With increasing temperature,the corrosion resistance properties of super 13Cr tubing steels decrease,while the tendency of corrosion increases.The protection properties of passive films decrease for the substrate,which are significant with the solution above 60 ℃.The localized corrosion of super 13Cr tubing steels is caused by pitting in NaCl solution at different temperatures,and then results in general corrosion.The corrosion products consist of Fe and Cr oxides,which are incompact.