锌合金电子元器件多层电镀及镀层性能研究

采用多层电镀技术在锌合金基体上镀Ni-Cu-Ni镀层,研究阳极活化剂、电流密度、镀液温度、p H值及搅拌方式等对Ni-Cu-Ni镀层特性的影响,以无氰镀铜替代有氰镀铜Ni-Cu-Ni多层电镀工艺,通过增加中间Cu层厚度降低整体镀层中贵重金属Ni的用量以实现降低成本、无毒环保的绿色新工艺.研究表明,普通Ni作为打底层,镀酸Cu为中间层,镀光亮Ni作表层,利用镀层电位差及镀层错位效应可有效减少贵重金属Ni的用量,并在保持镀层美观的同时满足防腐等表面处理要求;Ni-Cu-Ni镀层结合力良好,150℃热震及锉刀划痕试验镀层无脱落起皮,镀件耐NSS可达48 h,耐5.0%Na Cl浸泡可达100 h.

Perfomance of multiple plating and coating layers of zinc alloy electronic components

For multi-layer plating technologies on the zinc alloy substrate plating with Ni-Cu-Ni layers, effects of the anode activator, current density, electrolyte solution temperature, pH and the mixing way on properties of Ni-Cu-Ni plating layers are studied. Our new technology is low-cost, non-toxic, and environmental friendly since the Ni layer was partially replaced by the Cu layer, saving the amount of noble metals Ni in the whole coating, as well as using a cyanide-free plating instead of cyanide plating. Results showed that the common Ni as a bottom layer, the acid Cu plating as a middle layer, the bright plating Ni as a top layer can effectively reduce the potential difference in the coating and plating resulting in saving the amount of noble metals Ni. Meanwhile, the excellent coating appearance was achieved as well as the anti-corrosion surface. Binding force between Ni-Cu-Ni plated layers and substrates was good, and the layers were not peeled or blistered at 150℃ heat shock in the peeling file scratch test. The NSS resistance time of plating pieces is 48 h, and resistance time immersed in 5.0% NaCl solutions was 100 h.