闪镀镍对冷轧板表面耐蚀性的影响

目的提供一种提高冷轧板(普冷板)表面耐蚀性的新方法。方法在冷轧板表面闪镀镍。利用扫描电镜观察表面形貌,利用EDS能谱测定表面沉积的镍元素含量,测试Tafel极化曲线和交流阻抗谱,研究闪镀镍对冷轧板表面状态和电化学性能的影响。采用点滴实验和湿热实验评价冷轧板表面的耐蚀性能。结果当闪镀温度为45~55℃,电流密度为3~6 A/dm2,闪镀时间为15~20 s时,沉积到基板表面的镍元素原子数分数达到40.1%以上。此时,冷轧板表面的点滴变色时间明显延长,在潮湿条件下的锈蚀面积明显减少。电化学测试也发现在冷轧板表面闪镀镍后,表面腐蚀电流明显降低,交流阻抗弧变大。结论闪镀镍可以改变冷轧板的表面状态和电化学性能,使冷轧板的表面活性和腐蚀倾向有所降低,从而提高冷轧板表面的耐蚀性能。该研究为冷轧板存储、运输、使用过程中的防锈提供了一种新方法,且方法简单有效、环保、实用。

Effects of the Pre-plating Ni on Corrosion Resistance of Cold Rolled Plate

ABSTRACT:Objective To provide a new way to improve the corrosion resistance of cold rolled plate. Methods The pre-plating Ni was used on the surface of cold rolled plate. The surface properties and electrochemical performance of the cold rolled plate were studied by scanning electron microscope ( SEM) , electrochemical methods, and energy dispersive spectrum analysis. The corrosion resistance of cold rolled plate was studied by damp heat test and spot test. Results The nickel content of substrate surface was over 40. 1% under conditions of temperature 45~55 ℃, current density 3~6 A/dm2 and electroplating time 15~20 s. The time of CuSO4 dropping corrosion test was significantly increased and the corrosion area was reduced. Electrochemical test showed that the properties was significantly improved. The corrosion resistance of cold rolled plate was remarkably enhanced. Conclusion Flash nickel plating could change the surface state and electrochemical properties of cold rolled plate. Surface activity and corrosion tend-ency were reduced. The corrosion resistance was greatly improved. This method might provide a new technique for the storage, transportation and use process of cold rolled plate, which is simple, effective, environment friendly and practical.