Synthesis of silver powder using a mechanochemical process

Fine silver powder was synthesized in a mechanochemical process by inducing a solid-state displacement reaction between AgCl and sodium. The process employed was ball milling in a planetary-type ball mill. The reaction products were elemental silver and NaCl in powder form. The silver particles were separated out by washing the NaCl by-product from the milled powder mixture. The milled powders were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD determination showed that the reaction between AgCl and sodium was complete in almost all the experiments carried out. In some cases a minor quantity of Ag₂Na was formed. SEM and TEM examinations revealed that, depending on the milling parameters employed, the size of the particles in the synthesized metallic silver powder was in the range 50-1000 nm.