Preparation of ultra fine copper–nickel bimetallic powders for conductive thick film

In this paper, ultrafine nickel-rich Cu–Ni bimetallic powders were synthesized with hydrothermal-reduction method. When polyethyleneglycol (PEG) was employed as protective agent, flake bimetallic powder particles, which have an excellent dispersibility and uniform size of 1.8–2.0 μm, can be prepared. Polyhedral powder particles, which have a uniform particle size in the range from 0.5 to 0.8 μm, were successfully synthesized using gelatin as protective agent. By thermal analysis, it was found that the oxidation-resistance of Cu–Ni powder particles was strong. Above-mentioned flake/polyhedral bimetallic powders were mixed with inorganic binder and vehicle to make conductive thick film. The low resistivity and high adhesion strength of thick film were attributed to high densification and rough interface from interfacial reaction, respectively.