采用动电位极化曲线、恒电位极化曲线、电化学阻抗谱(EIS)、Mott-Schottky分析等电化学方法研究了X80管线钢在各种高浓度的NaHCO3溶液中形成钝化膜的电化学行为。结果表明， X80管线钢钝化膜的稳定性和耐蚀性会受到NaHCO3溶液浓度的影响。钝化膜电化学性质随HCO3-浓度升高而降低；内层Fe3O4的厚度不随HCO3-浓度变化，推测其形成与成膜电位有关；内外膜层厚度比随HCO3-浓度的升高而增大，钝化膜的稳定性和耐蚀性主要受外层γ-Fe2O3的影响。根据点缺陷(PDM)理论的分析认为，NaHCO3溶液浓度升高时钝化膜稳定性和耐蚀性的降低与溶液电导率的升高和HCO3-在缺陷点处吸附作用的增强有关。
The electrochemical behavior of the passive films formed on X80 pipeline steel in various concentrated NaHCO3 solutions was studied using potentiodynamic polarization curves, potentiostatic polarization curves, electrochemical impedance spectroscopy (EIS) as well as Mott-Schottky plots. The electrochemical test results indicated n-type semiconducting characters of the passive film, which was composed of two layers, with γ-Fe2O3 as the outer layer, and Fe3O4 as the inner layer. The properties of the passive films were influenced by the concentration of NaHCO3 solutions. The thickness of the inner layer merely remained constant, which was supposed to be dominated by the film forming polarization, whereas the thickness of the outer layer decreased with the increase of the concentration of NaHCO3 solution, which suggested that the outer layer plays a more important role to the corrosion resistance and stability of the passive film. According to the point defect model (PDM), higher donor density and lower thickness of the passive films was affected by the enhanced conductivity of the solution and the intensified adsorption of HCO3- at local defect sites with higher HCO3- concentration.
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| [3] | |
| [4] | |
| [5] |
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