锌铁及其合金镀层黑色钝化膜耐蚀性能的研究

为了提高Zn-Fe合金镀层及Zn-Fe-TiO2复合镀层的耐蚀性,采用非银盐发黑剂,结合磷化工艺,并加入适当的添加剂及辅助成膜剂,系统研究了含铁0.2%～0.8%的Zn-Fe合金镀层黑色钝化工艺,得到了最佳的镀液组成及工艺条件.采用这种钝化工艺获得的钝化膜油黑发亮,色调均匀,耐蚀性高,附着力强,耐磨性好.在最佳镀液组成及工艺条件下,对Zn镀层、Zn-Fe合金镀层及Zn-Fe-TiO2复合镀层黑色钝化膜的耐蚀性进行了研究.5%NaCl中性溶液浸泡实验表明,经黑色钝化后,Zn-Fe合金镀层及Zn-Fe-TiO2复合镀层的耐蚀性有了很大的提高.Zn-Fe合金镀层的耐蚀性是纯Zn镀层的3倍多;Zn-Fe-TiO2复合镀层的耐蚀性是Zn-Fe合金镀层的2倍左右,是纯Zn镀层的5倍左右,是一种理想的代镉镀层.

Black Passivation and Corrosion Resistance of Zn-Fe Alloy Coatings

In order to improve the corrosion resistance of Zn-Fe alloy coating and Zn-Fe-TiO_2 composile coating, a black passivation technology was developed for Zn-Fe alloy coating containing 0.2% -0.8% Fe. In the process, phosphatization was incorporated to increase the thickness of the coatings, and transition element salt was used as a blackening reagent to take the place of the soluble silver salt, aside the adequate additives and assistant film torming agent were added. The optimal electrolyte components and process conditions were obtained. The obtained black chromate film has the properties of black and shining, uniform hue, high corrosion resistance, good adhesion and wear resistance. The corrosion resistance of black passivation fihn of Zn, Zn-Fe and Zn-Fe-TiO_2 electroplating were studied. The corrosion test (in 5% NaCI) shows that being black passivated, the corrosion resistance of Zn,Zn-Fe and Zn-Fe-TiO_2 coating make a good progress. Among them, the corrosion resistance of Zn-Fe-TiO_2 composite coating with black chromate fihn is more than two times of Zn-Fe coating,and 5 times of pure Zn coating. The composite coating reaches the domestic advanced level, and is an ideal substitute for cadmium coaling.