低碳钢在湿热工业海洋大气中的腐蚀特征

以0.1 mol·L-1 NaCl+0.01 mol·L-1 NaHSO3溶液为腐蚀介质,采用干/湿周浸加速腐蚀实验、腐蚀失重、X射线衍射、扫描电镜和能谱分析等方法,研究了湿热工业海洋大气中低碳钢的腐蚀行为.结果表明:实验钢的腐蚀过程均遵循幂函数d=Atn分布规律,钢种不同,常系数A、n的值不同;腐蚀产物主要由非晶物质和少量Fe3 O4、α-FeOOH、β-FeOOH、γ-FeOOH晶体组成.所得锈层可分为主体锈层和界面疏松带两部分,由内至外锈层中Fe、O含量梯度变化很小.Cl-、SO2与水分的长期协同作用会导致内锈层结构变差,而添加稳定性或耐蚀性较高的元素可以改善锈层质量,进而增强钢材的耐腐蚀性能.

Corrosion characteristics of low-carbon steel in hot and humid industrial-marine atmosphere

The corrosion behavior of low-carbon steel was investigated in a simulated hot and humid industrial-marine atmosphere by X-ray powder diffraction ( XRD) , scanning electron microscopy with X-ray microanalysis ( SEM-EDS) , mass loss, and a wet/dry alternate immersion corrosion test using a 0. 1 mol·L-1 NaCl+0. 01 mol·L-1 NaHSO3 solution. The results indicate that the corrosion processes of the experimental steels agree well with the d=Atn power function, with different steels having different values of A and n. The corrosion products are mainly in the amorphous phase and contain a small amount of Fe3 O4 ,α-FeOOH,β-FeOOH, andγ-FeOOH crystals. It can be found that the rust layers have two parts—the body of the rust layer and a loose interface band. The Fe and O con-tent gradients in the rust layer, from inner to outer, change very little. It can be concluded that the long-term interaction of Cl-, SO2 and H2 O will lead to the deterioration of the inner structure. However, the addition of elements with high stability or corrosion resist-ance can improve the stability and density of the rust layer, and thereby enhance the corrosion resistance of the steels.