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对碳钢和Cr含量不同的实验钢在流速为0.8m/s的流动的3.5%(质量分数)NaCl溶液中的腐蚀行为进行研究,最长腐蚀周期为192h。对4种实验钢的腐蚀失重进行了比较,并利用动电位极化曲线、SEM、EPMA和TEM等分析手段,对实验钢表面形成锈层的特征进行了系统研究。结果表明,含Cr实验钢的腐蚀失重低于碳钢,并且随Cr的质量分数由0.5%提高至2%,腐蚀失重亦降低。Cr元素在内锈层中的富集是含Cr钢耐蚀性改善的重要原因。这种富集可使腐蚀产物颗粒获得细小的尺寸,致密内锈层形成的原因就是由于这种尺寸细小的腐蚀产物的形成,使内锈层的保护性获得明显的改善。
The corrosion behavior of experimental steels with different contents of carbon steel and Cr was investigated in 3.5% (mass fraction) NaCl solution with flow rate of 0.8 m / s, and the longest corrosion period was 192 h. The corrosion weight loss of the four kinds of experimental steels was compared. The characteristics of the rust layer on the surface of the experimental steels were systematically studied by means of potentiodynamic polarization curves, SEM, EPMA and TEM. The results show that the corrosion weight loss of Cr-containing experimental steels is lower than that of carbon steels, and the corrosion loss decreases with the mass fraction of Cr from 0.5% to 2%. The enrichment of Cr element in the inner rust layer is an important reason for the improvement of the corrosion resistance of Cr steel. This kind of enrichment can make the particles of the corrosion product obtain the fine size. The reason of the formation of the dense rust layer is that the formation of the corrosion product with the small size obviously improves the protection of the internal rust layer.