Acidic electroless copper deposition on aluminum-seeded ABS plastics

Copper (Cu) was successfully deposited onto aluminum (Al)-seeded acrylonitrile–butadiene–styrene (ABS) plastics in acidic electroless baths containing 15 wt.% copper sulfate and 5 wt.% of any of the acids including sulfuric acid (H2SO4), phosphoric acid (H3PO4), nitric acid (HNO3), or acetic acid (CH3COOH). Cu crystals were formed on the Al-seeded ABS surfaces deposited from all of the four acidic baths. Electroless Cu deposition was carried out at both room temperature and 60 °C, and the deposition rate was dramatically increased at the elevated temperature. Conductive Cu layers were developed on ABS surfaces only from the H2SO4, H3PO4, and CH3COOH baths but were not from the HNO3 one, and the possible reason of failure of the HNO3 bath is discussed. The electrolessly Cu deposited ABS surfaces were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The adhesion of conductive Cu layers to the ABS substrates was assessed and showed excellent strength. The acidic baths developed in this study may provide more alternative options for plating on plastics (POP) via the acidic electroless Cu deposition route.