CHARACTERIZATION OF SILVER-PALLADIUM SUBMICRONIC POWDERS .1. MORPHOLOGY AND THERMAL-PROPERTIES

Various properties of submicronic silver-palladium powders (70/30 and 75/25 Ag/Pd % wt/wt), recently obtained by a new process of precipitat ion in aqueous solution, are described. These powders are intended to be used in the multilayer ceramic capacitor industry. The morphology o f the particles has been analysed through various measurements, such a s SEM images, tap density, BET surface area, and the size distribution by a sedimentation technique. The powders were found to be made of sp herical shaped particles of mean diameter close to 0.3 mu m with a nar row size distribution. The individual grains were agglomerated only to a small extent. After being conditioned as a paste by blending with a n organic binder, screen-printed and fired, the particles sintered int o a conductive layer of low resistivity (15-30 mu W cm for 2 mu m thic kness) with only a few remaining voids, as observed by SEM. Thermal me asurements indicated no melting of a pure silver phase at 960 degrees C, thus indicating that alloying was achieved before this temperature.