ABS (Acrylonitrile Butadiene Styrene) is commonly used in Plating on Plastic, although another type like Polypropylene can be used.
Plating on Plastic Process
Cleansing for Plastic can be used chlorinated solvent, DMF (Dimetylformamide), or Methanol. Should be done two cleansing process, the first using solvent and the second by using emulsifier to dissolved solvent with soil to the water, and to make easy rinsing.
Conditioning or Etching for ABS Plastic is very needed for Plating on Plastic. Etching process at the ABS Plastic using strong oxidation agents like Chromic Acid and Sulfuric Acid. Excessive etching process can degradation of the surface, and blister occur.
Concentrated sulfuric acid (s.g. 1.84) 50 % (v/v)
Water 50 % (v/v)
Chromic acid to saturation 15 g/lt
Sensitizing and nucleation actually as two different processes, sensitizing use the stannous ion or titanium, and nucleation use palladium ion. At this time, nucleation and sensitizing has been one process, there already containing HCl, Sn2+, Pd2+, and Sn4+ as a stabilizer of the palladium ion.
In the nucleation process, Palladium is not reduced to catalytic form, but merely absorbed as a Palladium (II) salt. In The Post nucleation process, The palladium is reduced to metallic form by means of a strong reducing agent, such as hypophosphorus acid or dimethylamine borane (DMAB).
Electroless nickel is commonly used, because it is more stable than electoless copper, only the operating temperature is adjusted to low temperatur.
Acid Copper layers have a more ductile with a bright and a good leveling than other layer, that is suitable for plating on plastic early.
Bright Nickel Plating
Bright nickel layer need not be too thick when the drying is done at room temperature.
Among the above process, the conditioner (etching) process is most attention. The speed reaction of conditioner depends on the composition of the mixture used.
Plastic Chrome process above is very suitable for mass production process. Carbon powder or copper powder layer can be used for conductive coating at Plating on PCB.