Process for manufacture of silver-based particles and electrical contact materials

US7842274B2 · kind B2 · utility

Assignee

• Umicore, S.A. · BE

Inventors

• Dan V. Goia · Potsdam, US
• Sebastian Fritzsche · Hanau, DE
• Bernd Kempf · Alzenau, DE
• Peter Braumann · Alzenau, DE
• Thierry Charles Simon Vandevelde · Zolder, BE

Key dates

• Filing date: Mar 31, 2006
• Grant date: Nov 30, 2010
• Expiry date: Nov 28, 2027

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01H1/027
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

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° 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 …