Experimental Study on the Preparation of Superfine Silver Powder by Precipitation-transformation Method

An experimental study on the preparation of superfine silver powder by precipitation-transformation method was carried out with Ag2O as precursor,glucose as reducing agent,and PVP or other surfactants as dispersant.The effects of pH,dispersants,temperature,and concentrations of glucose on the morphology and size of the silver powder were investigated.The results show that particle size decreased at first and then increased with the rising of pH,acidic condition resulted in a wide size distribution,and basic condition lead to obvious aggregation and a wide size distribution of the silver particles;well dispersed spherical-like superfine silver powder could be obtained with PVP as dispersant;particle size decreased with the increasing concentrations of glucose;particles became larger and more agglomerated under the rising of temperature.Spherical-like superfine silver powder with good dispersity and particle size around 1 μm was prepared by a controlled double-jet process(CDJP)adding glucose(0.35 mol/L)and ammonium solutions(0.18 mol/L)into 100 mL ultrapure water containing 8 g Ag2O and 0.08 g PVP with reaction temperature maintained at 30 ℃ and pH at 8.0,and the particle size was under control.