带锈层NSB钢在模拟海水中的电化学腐蚀行为

采用极化曲线测试和电化学阻抗测试(EIS)方法研究带锈层NSB钢在3种温度(0,15,30℃)下、质量分数为3.5%的NaCl溶液(模拟海水)中全浸20 d后的电化学腐蚀特征,利用扫描电子显微镜观察试样腐蚀形貌,并对锈层的组成进行X射线衍射分析。结果表明:随着温度的升高,试样的腐蚀电流密度显著增加而电荷转移电阻降低;30℃全浸试样腐蚀锈层较0℃的疏松多孔,锈层对基体的保护作用减弱;全浸试样锈层由γ-FeOOH,α-FeOOH和Fe3O4三相组成,温度越高,锈层中具有良导电性的Fe3O4含量越高,导致试样耐蚀性下降。

Electrochemical Corrosion Behavior of NSB Steel with Rust Layer Simulated Seawater

The corrosion behavior of NSB steel with rust layer in 3.5%（w/%） NaC1 solution （simulated seawater） at three different temperatures （0, 15 and 30 ℃） was investigated by the measurement of polarization curves and electrochemical impedance spectroscopy （EIS）. The morphology and phase composition of rust layer were analyzed by scanning electron microscope （SEM） and the rust layer composition were analyzed by X-ray powder diffraction （XRD）. It is found that the corrosion current density of NSB steel increased remarkably and the charge-transfer resistance was reduced with the rising of the temperature; Due to loose and porous rust layer, the protection of rust layer at 30℃ is lower in comparison to that at 0℃; The rust layer is composed of γ-FeOOH, α-FeOOH and Fe3O4 phases; The fall of the corrosion resistance is attributed to the increasing of Fe3O4 with high conductivity at high temperature.