Electroless plating route to the synthesis of glass microspheres/copper composites with excellent conductivity

A versatile electroless copper plating method for the fabrication of Cu-coated glass microspheres was successfully developed using hydrazine hydrate as the reducing reagent. To obtain the best morphology and electrical conductivity of Cu-coated glass microspheres, some main synthetic factors including the concentration of copper salt, volume of aqueous ammonia and bath temperature were investigated in detail. The crystal structure and shape of the copper layer were characterised by X-ray diffraction and scanning electron microscope techniques. The result showed that the glass microspheres with a uniform copper coating exhibited a face-centred cubic crystal structure and an excellent volume resistivity (ρ_ν) of 4.28 × 10^-4 Ω·cm. This method could also be extended for the fabrication of Ag- and Co-coated glass microspheres with superior conductivity.