Preparation of micron size copper-silver bimetallic powders

Spherical silver-rich copper-silver bimetallic powders having a uniform size of 0.6 similar to 0.8 pm have been synthesized with the two-stage reduction method. Ascorbic acid was first applied as reducing agent to control the formation rate of nuclei and growth rate of particles effectively, and then hydrazine hydrate was used to reduce metal completely. When pH value of reductive solution was stably controlled in the range of 7 similar to 8, non-agglomerated monodispersed silver-rich Cu-Ag bimetallic particles with smooth surface and uniform size were synthesized. With increasing silver content in powders, the particle size and dispersibility of bimetallic powders decreased and increased, respectively. The XRD and thermal analyzer were employed to analyze as-prepared bimetallic powders.