Effects of Cl- Ions on the Corrosion Behaviour of Low Alloy Steel in Deaerated Bicarbonate Solutions

作     者：Yunfei Lu Junhua Dong Wei Ke 

作者机构：Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Wuhan the Second Ship Design and Research Institute Wuhan 430064 China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2016年第32卷第4期

页      面：341-348页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

主　　题：Low alloy steelCorrosion behaviourCI Open circuit potentialElectrochemical impedance spectroscopy(EIS) 

摘      要：The effect of Cl- ions on corrosion evolution of NiCu low alloy steel during immersion tests （up to 70 days） in deaerated 0.05 mol/L bicarbonate solutions was investigated by in-situ electrochemical mea- surements combined with X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electron probe microanalysis （EPMA） characterisations. The results showed that due to the acceleration of substrate dis- solution in the presence of Cl, corrosion of NiCu low alloy steel underwent only two stages, i.e., a quick oxidation process followed by a final metastable passive state, without the initial slow anodic dissolu- tion as observed in the Cl--free bicarbonate solution. The main components of the formed rust layer in the Cl--free bicarbonate solution were α-FeOOH and Fe3O4, while apart from α-FeOOH, Fe6（OH）12CO3 was found evident instead of Fe3O4 in the Cl-containing solution. Metastable pits were only found in the Cl-containing solution where Cl- accumulated after the immersion test, confirming the attack of Cl on the substrate after penetrating the formed corrosion product layer.