碳钢化学镀镍层无铬钝化工艺的研究  

Study on Chromium-Free Passivation of Electroless Nickel Coating on Carbon Steel

作　　者：杨春 

机构地区：[1]贵州理工学院化学工程学院,贵州贵阳550003

出　　处：《电镀与环保》2018年第1期36-39,共4页Electroplating & Pollution Control

基　　金：铝合金化学镀镍低铬钝化综合研究[黔科合区域合(2014)7007]

摘　　要：化学镀镍层通常采用铬酸盐进行钝化。钝化液中含有六价铬,废水处理成本很高。以镀层的耐硝酸变色时间为评价指标,根据钝化成膜理论,分别以VIB族元素的三种常见化合物——重铬酸钾、钼酸钠、钨酸钠为钝化剂,考察其钝化作用。然后,在选定的无铬钝化液中分别添加两种有机物质——植酸和二乙醇胺,考察用其钝化处理后镀层的耐硝酸变色时间。最后,将钼酸钠、植酸和二乙醇胺进行复配,并设计正交试验优化无铬钝化液的组成,并与传统铬酸盐钝化液的效果进行对比。结果表明:采用钼酸钠25g/L、植酸2.5mL/L、二乙醇胺3.0mL/L所组成的无铬钝化液对碳钢化学镀镍层进行钝化,耐硝酸变色时间可大幅提升至404s,与传统铬酸盐钝化的耐硝酸变色时间(416s)很接近。Electroless nickel coating was treated generally using chromate passivation. The passivation solution contains hexavalent chromium, and the cost of wastewater treatment is very high. The tarnish time of resistance to nitric acid was taken as an evaluation index, and according to the theory of passivation film formation, the passivation action of three kinds of common compounds in the periodic table VIB group elements, like potassium dichromate, sodium molybdate and sodium tungstate, as the passivating agent, was studied. Then, adding two kinds of organic substances, phytic acid and diethanolamine, in the selected chromium-free passivation solution to investigate the passivation treatment on the tarnish time of resistance to nitric acid. Finally, the sodium molybdate, phytic acid and diethanolamine were mixed and orthogonal test was designed to optimize the composition of the chromium-free passivation solution, and the effect of chromium-free passivation solution was compared with that of traditional chromate passivation solution. Results showed that, the chromate-free passivation solution consisting of sodium molybdate 25 g/L, phytic acid 2. 5 mL/L and diethanolamine 3.0 mL/L was used for passivation of electroless nickel coating on carbon steel, the tarnish time of resistance to nitric acid could be greatly increased to 404 s. The effect was close to that of traditional chromate passivation（the tarnish time of resistance to nitric acid was 416 s）.

关 键 词：化学镀镍层 无铬钝化 耐硝酸变色时间 正交试验 

分 类 号：TG174[金属学及工艺—金属表面处理]