Zn-Al多元共晶合金镀层助镀工艺及耐蚀性研究

Reaserach on the Fluxes and Corrosion Resistance of Hot Dipping Zn-Al Base Multi-element Eutectic Alloy

用正交试验法研究了Zn-Al多元共晶耐蚀合金镀层的助镀工艺条件,用动电位极化法研究了几种镀层在中性NaCl溶液中的耐蚀性能,并分别对镀层的形貌和元素分布进行了观察和分析。极化数据的极差分析结果表明,助镀剂中含0.5%(质量分数,下同)CeCl3、助镀时间7 min、助镀温度80℃的镀层耐蚀性能最优,而且助镀工艺中CeCl3含量对其影响最大。镀层SEM观察和成分分析的结果也表明在助镀剂中添加一定量的CeCl3能使镀层组织致密,厚度增加,界面光滑,与基体结合良好,从而改善了镀层的性能。

The fluxing technology of hot-dip Zn-Al base multi-element eutectic alloy（ZA） was investigated by orthogonal test method.The corrosion resistance of ZA coatings in NaCl solution was tested by potentiadynamic polarization method at room temperature.On this base,the morphology and composition of the hot-dip ZA coatings were observed and analyzed by using scanning electron microscopy with energy dispersive spectroscopy.The range analysis results of electrochemical measurements indicate that the optimized composition and treatment parameters of hot dipping ZA fluxe are recommended as weight fraction of cerium chloride 0.5%,fluxing time 7 min,fluxing temperature 80℃,and that the content of cerium chloride in the fluxes has a significant effect on the corrosion resistance of ZA coatings.The SEM results also show that the addition of an appropriate cerium chloride in the fluxes could make the hot dipping ZA coatings have dense microstructure,increased thickness,smooth interface and well bonding with steel substrate,which improved the coatings＇ properties.