酸性镀锌三价铬彩色钝化工艺研究
我们经过研究与探索,研究出一种实用型的三价铬钝化工艺。该工艺以CrCl3为主成膜剂;硝酸盐为氧化剂;Ni2+为活化金属离子,活化钝化液及增加钝化膜的耐蚀性。通过单因素实验,得到了这种三价铬彩色钝化液的最佳配方及工艺条件:50g/L铬盐, 10g/L硫酸镍,12g/LNaNO3,3g/L十二烷基硫酸钠。实验中还探讨了pH值、钝化温度、钝化时间和封闭剂浓度和耐蚀性的关系,并对钝化膜的成膜机理进行了简要的讨论。
根据国家标准的检验方法检验了这种三价铬钝化膜的性能，结果表明，该钝化膜具有满意的附着力，钝化膜呈现彩色，能够通过72小时的中性盐雾试验。但与吹冰价铬钝化膜相比还存在一定的差距，有待于进一步提高。
关键词： 三价铬；锌镀层；彩色钝化
Abstract： The purpose of this object is to find a low environmental toxicity of trivalent chromium passivation process, to replace the highly toxic hexavalent chromium passivation process. The new technics can form a Cr(Ⅲ) conversion layer which can present a corrosion protection of above 72h in the salt spray test.
Through a period of exploring and researching process, we find a new colorized trivalent chromating technology. In this processing solution, Cr(Ⅲ) which is offered by Chromium trichloride is the main element of the conversion layer; Nitrate is the oxidant; Ni2+ present in an amount effective to activate the bath and improve the corrosion resistance of the passivate film. According to one-way method, the optimal process conditions of a Cr(Ⅲ) passivate solution was obtained: 50g/L chromic salts, 10g/L nickel vitriol, 12g/LNaNO3,3g/L sodium dodecylsulfate, pH1.8,passivation temperature 30℃,passivation time 60s. The correlation among the passivating parameters and the morphology and corrosion resistance of the electroplated zinc coating were explored. The formation mechanism of passivate film were also discussed.
According to the national standard method, we test the performance of the trivalent chromium passivation film. The results show that the capability of the passivation film is satifacted. The passivation film has decorative colorized, and can pass 72 hours NSS test. However, there is still a gap compared with the hexavalent chromium passivation film, so the thchnic should be further improved.
Keywords: Cr(Ⅲ)； Zinc plating； Colorized passivation
目录
１．前言 1
1．1 三价铬彩钝的概况及内容1
1．2 三价铬彩钝研究的内容、目的（目标） 1
1.2.1 主要研究的内容1
1.2.2 本实验预期所要研究达到的目标1
1．3 三价铬彩钝工艺在国内外的过去及发展趋势2
1.3.1 第一代三价铬钝化技术3
1.3.2 第二代三价铬钝化技术3
1.3.3 第三代三价铬钝化技术3
1．4 三价铬彩钝的主要技术要求3
1.4.1 p H的调整: 4
1.4.2 氧化剂的调整4
1.4.3 铸件及酸性镀锌三价铬彩色钝化: 4
1.4.4 现有基础: 4
２．工艺技术原理5
2.1 添加剂的作用原理5
2.1.1 三价铬Cr(Ⅲ)钝化膜的主成分来源 5
2.1.2 氧化剂 5
2.1.3 络合剂 5
2.1.4 其他金属 5
2.1.5 成膜促进剂 6
2.1.6 封孔剂 6
2.1.7 润湿剂 6
3．工艺试验研究方法 8
3．1 工艺试验的方法 8
3．2 基础溶液及操作条件的确定和配制方法 8
3.2.1 氯化钾光亮镀锌：8
3.2.2 本实验所采用的工艺9
3.3选择钝化工艺配方和操作条件9
3.3.1 成膜剂9
3.3.2 氧化剂9
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