以镀酸性锌镍合金作为底层的电镀白铜锡工艺

Process for electroplating white copper–tin alloy with electroplated zinc–nickel alloy coating as a bottom layer

先通过酸性锌镍合金电镀工艺在钢铁基体或锌合金基体表面电镀锌镍合金,以代替传统的氰化物镀铜底层和氰化物镀黄铜锡中间镀层,然后电镀白铜锡。这种镀层结构在热震试验后没有出现镀层起泡和脱落,在中性盐雾试验24 h内没有红锈生成,具有较高的结合力和耐蚀性。

Zn–Ni alloy coating is electroplated as a bottom layer on either steel or zinc alloy substrate in an acidic bath for further white Cu–Sn alloy electroplating, which replaces the traditional copper bottom layer or yellow Cu–Sn intermediate layer electroplated in cyanide-containing baths. The coatings obtained have good adhesion and corrosion resistance in that no blistering or fall-off occurs after thermal shock test, and no red rust is formed in a 24-hour neutral salt spray test.