Abstract：Effect of the concentration of AgNO_3 and ascorbic acid, the temperature and pH of reaction system, the type and dosage of addition agent on the morphology of ultrafine silver powders by liquid phase reduction method were explored.Particles were characterized and analyzed with SEM, particle size analyzer, surface area analyzer and particle image analyzer. It shows that pH value is a significant factor affecting the particle size, morphology and dispersion simultaneously, while the dosage of addition agent and ascorbic acid concentration are significant factors affecting particle morphology and dispersion respectively.As the pH value gradually increased from 2 to 10, particles presented shape change by irregular polyhedron, rod-shaped to spherical, and average particle size gradually decrease. As the dosage of addition agent increase, particles present shape change by irregular to spherical, spiky ball, and the sphericity of particles is the greatest when the dosage was 2.5%.With increasing ascorbic acid concentration, the dispersion of particles become worse, and particles are at best dispersion when it is 0.5 mol/L.

Keywords: ultrafine silver powders; liquid reduction method; process parameters; morphology