Umicore, S.a.

Thierry Charles Simon Vandevelde

Dan V Goia

Bernd Kempf

Peter Braumann

Sebastian Fritzsche

The invention is directed to a process for manufacture of fine precious metal containing particles, specifically silver-based particles and silver-based contact materials via an intermediate silver(+1)-oxide species. The process comprises in a first step the formation of a thermally instable silver (+1)-oxide species by adding a base to an aqueous silver salt solution comprising an organic dispersing agent. Due to the presence of the organic dispersing agent, the resulting silver (+1)-oxide species is thermally instable, thus the species is decomposing to metallic silver at temperature lower than 100&#xb0; C. The process optionally may comprise the addition of a powdered compound selected from the group of inorganic oxides, metals, and carbon-based compounds. Furthermore the process may contain additional separating and drying steps. The process is versatile, cost efficient and environmentally friendly and is used for the manufacture of silver-based particles and electrical contact materials. Silver nanoparticles made according to the process are characterized by a narrow particle size distribution. Electrical contact materials manufactured according to the process reveal improved contact welding properties.

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Zolder, Belgium

Thierry Charles Simon Vandevelde