The invention relates to the preparation and storage method of
silver nano-particles for conductive
adhesive, in particular to a method for preparing
silver nano-particles by reducing high-concentration
silver nitrate by adopting a chemical liquid-
phase method. The method comprises the following steps: mixing
sodium hypophosphite,
polyvinyl pyrrolidone and
sodium hexametaphosphate to obtain reduction solution, adding
sulfuric acid dropwise to adjust pH value, adding
silver nitrate solution into the reduction solution under magnetically stirring to obtain
silver colloid, standing, centrifugally separating, recovering filtrate, concentrating, centrifugally separating, washing the
solid, vacuum-
drying to obtain
silver nano-particles, sealing and packaging, and storing at low temperature. The method adopts high-concentration
silver nitrate solution, and has the advantages of simple process flow, high yield of silver
powder, short
production cycle and good safety. In the
separation process, the filtrate can be recovered to improve the coefficient of
recovery of silver
powder. The silver nano-particle has spherical shape, uniform particle
diameter, narrow distribution, high purity, good dispersibility, good storage stability and long storage time without oxidization, and can be used for conductive filler such as conductive
adhesive.