Abstract

Silver powder was produced through water atomization with a pressure of 80 MPa and a flow rate of 220 L/min. Scanning electron microscopy analysis showed that as-prepared silver particles were aggregated and had various types of morphologies such as spherical, spheroidal and irregular. The volume average particle size of as-prepared silver powder was 7.7 μm at the drain rate of 0.024 kg/s. The particle size decreased with decreasing the drain rate. Powder X-ray diffraction revealed that the silver powder with a single phase and high crystallinity was formed. Surface treatment of silver powders classified to 5 μm was performed at 10,000°C by radio-frequency (RF) plasma under argon atmosphere. RF plasma treatment led to the formation of spherical particles from irregular particles. The crystallinity and crystallite of silver powder were increased by RF plasma treatment. X-ray photoelectron spectroscopy showed that the oxygen content in silver particles decreased from 500 ppm to 45 ppm. Thermomechanical analysis revealed that the shrinkage of silver powder reduced by the RF plasma treatment. It was clear that the particle characterization of silver powder was significantly modified by RF plasma treatment. The specific resistivity of silver paste sintered at 900°C exhibited 1.89×10^-8 Ωm.