低压冷喷涂Cu-Zn复合涂层耐蚀性能的研究

Corrosion Resistance of Low Pressure Cold Sprayed Cu-Zn Composite Coatings

摘要:

本文使用低压冷喷涂技术，分别在45#钢基体与45#钢加镀铬层基体上制备铜锌涂层试样。通过静态浸泡与铜加速醋酸盐雾腐蚀试验（CASS）对涂层和涂层加镀铬层试样的腐蚀性能进行研究；采用SEM、XPS对腐蚀前后涂层与镀铬层的微观形貌与元素进行表征。结果表明：静态腐蚀过程中，铜锌涂层的耐腐蚀性优于铜锌涂层加镀铬层；CASS实验中，随着原始粉体中锌含量的增加，涂层试样与涂层加镀铬层试样的耐腐蚀性能提高，当铜锌比为6:4时，对应涂层试样、涂层加镀铬层试样与纯镀铬层的耐腐性能达到六级。铜锌涂层在腐蚀液中由于电化学腐蚀及氯化作用，导致铜锌均发生了腐蚀，其腐蚀产物主要为Zn(OH)2、Cu2O与CuCl2。铜锌涂层加镀铬层试样在腐蚀过程中，锌的腐蚀在一定成上可以起到减缓镀铬层腐蚀的作用，这种减缓的作用与镀铬层上析出的铜膜共同保护镀铬层，增强其耐腐蚀性能。

Abstract:

In this paper, a low-pressure cold spray technique was used to prepare copper-zinc coated samples on 45# steel substrate and 45# steel plus chrome-plated substrate. Corrosion performance of coatings and coatings with chrome plating by static soaking and copper accelerated acetate spray corrosion test (CASS). The microstructure and elements of the coating and chrome plating before and after corrosion were characterized by SEM and XPS. The results show that the corrosion resistance of copper-zinc coating is better than that of copper-zinc coating plus chrome plating during static corrosion. In the CASS experiment, with the increase of zinc content in the original powder, the corrosion resistance of the coating sample and the coating plus chrome plating sample is improve. When the copper-zinc ratio is 6:4, The corrosion resistance of the corresponding coating sample, the coating plus chrome layer sample and the pure chrome layer reaches the sixth grade. Copper and zinc coatings are corroded in the corrosive liquid due to electrochemical corrosion and chlorination. The corrosion products are mainly Zn(OH)2, Cu2O and CuCl2. In the process of corrosion of copper-zinc coating and chrome-plated layer, the corrosion of zinc can play a role in slowing the corrosion of chrome plating. The effect of this mitigation together with the copper film deposited on the chrome layer protects the chrome layer and enhances its corrosion resistance.