【摘要】 采用动电位扫描和交流阻抗方法研究了X70管线钢在0.5 mol/L Na2CO3+1 mol/L NaHCO3溶液中的阳极极化过程中的电化学行为,通过XPS和SEM对表面膜的组成和形貌进行了分析.结果表明,X70管线钢在阳极极化过程中分别于-600 mV和-350 mV电位处出现2个阳极电流峰;-600 mV时电极表面的反应阻力较小,表面膜主要由FeCO3、Fe2(OH)2CO3和FeOOH等化合物组成,表面膜上存在较多的微孔缺陷,处在一个不稳定状态,表面膜的保护性能较差;-350 mV时电极表面的反应电阻较大,表面膜主要由铁的氧化物Fe2O3和Fe3O4组成,表面膜具有较好的保护性能.更多还原

【Abstract】 The electrochemical behavior of X70 pipeline steel in 0.5 mol/LNa₂CO₃+1 mol/LNaHCO₃ solution has been studied by potentiodynamic polarization and electrochemical impedance spectroscopy （EIS） methods.X-ray photoelectron spectroscopy （XPS） and scanning electron microscopy （SEM） were used to examine the composition and morphologies of the surface film.The results showed that there were two anodic peaks appeared at -600 mV and -350 mV respectively in the process of anodic polarization.For the surface film formed at -600 mV,the reaction resistance of electrode surface was small,it was mainly consisted of FeCO₃?Fe₂（OH）₂CO₃ and FeOOH.There were many hollows and microcracks existed in the film.The film was metastable and poorly protective.For the film formed at -350 mV,the reaction resistance of electrode surface was big,it was mainly consisted of Fe₂O₃ and Fe₃O₄ and it has good protectiveness.更多还原