Preparation of silver particles by spray pyrolysis of silver-diammine complex solutions

A novel precursor solution system, containing NH3 as a complexing agent, was used for the production of Ag powders by spray pyrolysis, Solutions of Ag2CO3, Ag2O, and AgNO3 with NH4HCO3 were used in this study. Ag powders were obtained at unexpectedly low temperatures, i.e., 400 degrees C or less. The Ag powders with a shell-like morphology were obtained from Ag2CO3 and Ag2O solutions, whereas dense Ag particles of about 1 mu m diameter were obtained from AgNO3-NH4HCO3 solution. These morphologies are explained in terms of NH3 release during spray pyrolysis.