摘要：热浸镀Zn-5%Al合金（Galfan）镀层的耐蚀性是热浸镀纯锌层的2-3倍，且可完全阻止含硅钢浸镀时的硅反应性。但是由于没有找到很好的助镀剂，目前还不能单镀Zn-5%Al合金的生产。本实验就热浸镀Zn-5%Al合金的助镀剂及助镀工艺进行了研究，分析了镀层的表面质量和镀层的显微组织，试图找出一种较好的助镀剂。
实验结果表明，使用氯化锌和氯化铵进行助镀时，不管两种物质的相对含量如何变化，都不能达到很好的助镀效果。在众多成分中，以氯化锌和氯化铵为1.5：1获得的助镀效果较好。在氯化锌和氯化铵水溶液助镀剂中添加氟化物也不能改善浸镀Zn-5%Al合金的助镀效果。而用135g/L ZnCl2、90g/L NH4Cl和90g/L SnCl2的水溶液进行助镀的助镀效果相对较好。但是溶液中呈乳白色，且在室温下会有沉淀。研究发现，钢件在Zn-5%Al合金中浸镀30s以下时，镀层中没有明显的合金层。镀层主要由液相凝固下来形成的组织组成。而随着浸镀时间的延长，会在镀层中形成Fe-Al化合物Fe2Al5和FeAl3，但形成的Fe-Al化合物层比较零乱。镀层中没有Zn-Fe化合物的形成。
关键词:热浸镀，Galfan，助镀剂，镀层
Abstract: The corrosion resistance of hot-dip plating of Zn-5% Al alloy coating is 2-3 times than that of pure zinc layer. And it can completely suppress the silicon reactivity when galvanzing Si containing steel. However, for did not find a suitable fluxing agent, we can not individually plating of Zn-5% Al alloy production currentlly. The present work conducted research on the fluxing agents and fluxing process of hot-dip plating Zn-5% Al alloy. The surface quality of the coating and the coating microstructure were analyzed. And I am trying to find a good fluxing agent.
The experimental results indicated that when use ZnCl2 and NH4Cl to assisted deposition, regardless of the relative content of the two substances change, can not achieved good help plated. Among the many agent, ZnCl2 and a NH4Cl with 1.5:1 seem much better. Add fluoride in ZnCl2 and NH4Cl aqueous solution fluxing agent can not improve the assisted deposition of hot-dip plating Zn-5% Al alloy. The aqueous solution of 135g / L of ZnCl2, 90g / L of NH4Cl and 90g / L SnCl2 to assisted deposition, the assisted deposition effect is relatively good. But the solution is milky white, and there will be precipitated at room temperature. The study found that the alloy layer was not significant observed when the dip time is less than 30s. The coating mainly composed of crystals solidificated from liquid. With the increasing of the immersion time，Fe-Al the compounds, Fe2Al5 and FeAl3, will be formed in the coating. But the formation of Fe-Al compounds layer is messy. The Zn-Fe compound will not formed in the coating.
Keywords: Hot-dip galvanizing, Galfan, Fluxing agent, Coatin
