无氰碱性镀锌工艺性能的研究

Study on technical properties of cyanide-free alkaline galvanizing

本次使用的无氰碱性镀锌溶液的分散能力和深镀能力良好。电流密度为1.70~2.00 A/dm2,镀液温度在21~22℃时,锌层的沉积速率约为20μm/h,镀液中锌离子的浓度对沉积速率影响较大。锌层外观为均匀细致的银灰色或银白色,钝化后带有绿色、黄色和紫色的彩虹色。锌层结合力、耐蚀性、氢脆性均符合HB5035—1992的要求。在锌层上制备氧化磷化膜,膜层外观和耐蚀性符合工艺的要求。以霍尔槽试验、锌层外观、沉积速率变化等为依据调整镀液中锌离子的浓度,可通过增大锌板阳极的面积或补加浓缩液来补充镀液中的锌离子。小零件的试镀效果良好,满足交付标准。

The dispersing ability and deep plating ability of the cyanide-free galvanizing plating solution used in this time were good.When the current density was 1.70-2.00 A/dm2 and the bath temperature is 21-22℃,the deposition rate of zinc layer was about 20μm/h,and the concentration of zinc ions had a great influence on the deposition rate.The zinc layer had a uniform and fine silver-gray or silver-white appearance,with iridescent colors of green,yellow and purple after passivation.The binding force,corrosion resistance and hydrogen brittleness of the zinc layer met the requirements of HB5035—1992.The oxidation phosphating film was prepared on zinc layer,and the appearance and corrosion resistance of the film met the technological requirements.By adjusting the concentration of zinc ions in the plating solution according to the Hall bath test,the appearance of zinc layer and the change of deposition rate,the zinc ions in the plating solution could be supplemented by increasing the area of zinc plate anode or adding concentrated liquid.The test plating effect of small parts was good and met the delivery standard.