Selective Gold Plating for Electronic Contacts
电子接插件的选择性镀金
标签：选择性镀金, 接插件, 硬金, 阻镀胶, 省金工艺
音响端子、连接器与高端键盘触点只需局部金：采用可剥离光成像阻镀胶或耐镀胶带贴覆非功能区，仅对触点闪镀硬金 0.05–0.15 μm（金钴合金、硬度 150–200 HV），其余区域只镀镍或镍锡。选择性镀比全板镀省金 80% 以上。工艺关键是阻镀胶边界的"爬金"控制——胶体须致密固化后入槽，电流密度压到 0.5 A/dm² 以下可避免金沿胶边侧向生长。批量件以金相切片与 XRF 测厚双重验证，抽检 AQL 1.0。
Audio terminals, connectors and premium keyboard contacts need gold only at the mating zones: mask non-functional areas with strippable photoimaging resist or plating tape and flash hard gold (Au-Co, 150–200 HV) at 0.05–0.15 μm, leaving the rest nickel or nickel-tin. Selective work saves over 80% of gold versus full-panel plating. The critical control is "gold creep" at resist edges—cure the mask densely and run below 0.5 A/dm² to stop lateral growth. Verify by metallographic cross-section plus XRF, AQL 1.0.