Incubation and development of corrosion in microstructures of low ahoy steels under a thin liquid film of NaCI aqueous solution

• Published in: International journal of minerals, metallurgy and materials metallurgy and materials, 2010, Vol.17 (6), p.748-755
• Main Author: Wen-hua Zhang Shan-wu Yang Jia Guo Zhi-yong Liu Xin-lai He
• Format: Article
• Language: English
• Subjects: 低合金钢; 化学成分; 微观结构; 扫描电子显微镜; 氯化钠水溶液; 腐蚀行为; 薄液膜
• ISSN: 1674-4799; 1869-103X

Electrochemical measurement, optical microscopy, and scanning electron microscopy were employed to investigate the corrosion behavior of some low alloy steels. The steels were held under a thin liquid film of 0.5wt% NaCl aqueous solution. It is found that the steels with the same chemical composition but different micmstructures exhibit obviously different corrosion behaviors. However, the corrosion behavior of the steels with different compositions but the same microstructnres may be similar in the present investigation. The corrosion rate of bainite is slower than that of ferrite and pearlite. The corrosion products of bainite are uniform and fine. The size of carbon-rich phases produces a great impact on the corrosion of the steels, whether in the initial stage or in the long tenn. It is easy to induce large pitting for carbon-rich phases with large size, which damages the compactness of the rust layer.