塑料电镀 Ⅳ——金属化学沉积(英文)

Plating on Plastics Part Ⅳ——Electroless Metal Deposition

采用金属的无电流沉积即化学沉积的方法使塑料表面导电以实现后续电镀,这一过程中的化学沉积并非真正"无电",只不过是利用"内电流"。目前,在塑料上化学沉积金属已经取得工业应用的体系有2种,一种是以甲醛为还原剂的化学镀铜,另一种是硼氰化钾或次磷酸盐为还原剂的化学镀镍。加入不同类型的稳定剂可以避免化学镀溶液的快速分解或者分解不受控制。印制电路板电镀适宜采用化学镀铜,而装饰性塑料电镀,尤其是高质量要求的塑料件则适宜采用操作更简易的化学镀镍作为电镀前的预镀。化学镀层薄而且仅仅能满足后续电镀所需的导电,可以采用高镀速体系。对于高镀速体系,有时候使用附加的专用设备是明智的。

To have a surface conductive for subsequent electroplating, electroless metal deposition is used, which is not really electroless but uses an internal current source. Today, two systems are used commercially: one is for the deposition of copper by means of formaldehyde as the reducer and another of nickel using either boranates or hypophosphite as reducer. Different kinds of stabilizers prevent such solution systems from rapid or uncontrolled decomposition. While the electroless copper systems are preferably used to manufacture printed circuit boards, the much easier to handle electroless nickel solutions are preferably used to pre-plate plastic material for decorative application, especially if high quality is on demand. While the thickness of the deposited metal is thin and just provides the necessary conductivity for subsequent electroplating, high speed systems are available which sometimes make special additional equipment reasonable.