US Patent 7776442 Particulate powder of silver and method of manufacturing same

A nanoparticle powder of silver has an average particle diameter measured by TEM observation (DTEM) of 30 nm or less, an aspect ratio of less than 1.5, an X-ray crystallite size (Dx) of 30 nm or less, a degree of single crystal grain {(DTEM)/(Dx)} of 5.0 or less, and a CV value {100×standard deviation (σ)/number average diameter (DTEM)} of less than 40%. The nanoparticle powder of silver has adhered to the particle surface thereof an organic protective agent having a molecular weight of 100 to 400. The nanoparticle powder is obtained by subjecting a silver salt to reduction treatment at a temperature of 85 to 150° C. in an alcohol having a boiling point of 85 to 150° C. and in the co-presence of an organic protective agent.