A novel surface activation method for Ni/Au electroless plating of acrylonitrile–butadiene–styrene

Direct electroless metallization on acrylonitrile–butadiene–styrene (ABS) plastic with Pd-free activation method could reduce the cost of production. A novel surface activation method with the immobilization of Ni(0) nanoparticles by chitosan (CTS) film on ABS and then the deposition of Ni and Au on ABS were investigated in this paper. X-ray photoelectron spectroscopy (XPS), fourier transform infrared (FTIR) spectra and scanning electron microscopy (SEM) data revealed the related interfacial reaction mechanism in activation process. The Ni(0) nanoparticles immobilized by the CTS films were effective auto-catalysts in the nickel electroless plating process. The formations of Ni plating layers at different deposition time were observed by SEM. The x-ray diffraction (XRD) patterns revealed the Ni layer at 30 min was in an amorphous phase. Au was successfully plated on the Ni layers in a new, stable non-cyanide Au electroless plating bath with different reducing agents. The chemical compositions of Ni/Au layers were analyzed by inductive couple plasmas (ICP) and ion chromatography (IC) measurements. Inorganic element (P or S) from reducing agents made the surface morphology of Au layers different in SEM images. However, they did not change the Au crystallization phase at all based on XRD patterns.