PROCESS FOR PRODUCING METALLIC NANOPARTICLE WITH LOW-TEMPERATURE SINTERABILITY, METALLIC NANOPARTICLE, AND PROCESS FOR PRODUCING DISPERSION CONTAINING THE SAME

摘要

Provided is a fine silver powder coated with a protective material and capable of being sintered at a considerably lower temperature than conventional ones. The fine silver powder comprises silver particles which have an average particle diameter (DTEM) of 3-20 nm or an X-ray crystal-grain diameter (DX) of 1-20 nm and have been coated with an organic protective material constituted of a C6-12 primary amine (B).  This fine silver powder has such a property that when the powder is mixed with an organic medium to prepare a silver coating material and this coating material is applied, then burning the resultant coating film in the air at 120°C gives a conductive film having a resistivity of 25 µO·cm or lower.  This fine silver powder can be produced by: mixing a C6-12 primary amine (B) with a silver particle dispersion which comprises an organic medium and, dispersed therein as primary particles, silver particles coated with a primary amine (A) having an unsaturated bond and a molecular weight of 200-400; and keeping the mixture at 50-80°C with stirring to yield sediment particles.