Silver and metal oxides electrical contact material and method for making electrical contacts

Abstract

The invention relates to a material for electrical contacts, in particular for contact studs in low-voltage switchgear. The material consists of silver, tin oxide and other additives. A material is sought where the overtemperature is lowered as compared with known AgSnO.sub.2 material. According to the invention, the further additives are in combination oxides of the metals tantalum (Ta.sub.2 O.sub.5), copper (CuO) and bismuth (Bi.sub.2 O.sub.3). Further the material may contain also tungsten or oxygen containing tungsten compounds. Preferably the material contains 5 to 20 mass % SnO.sub.2, 0.1 to 5 mass % Ta.sub.2 O.sub.5 5 mass % CuO, 0.1 to 5 mass % Bi.sub.2 O.sub.3, optionally 0.05 to 3 mass % tungsten and silver as balance. In the method for producing contact studs, the powder metallurgical production of the material is followed by extrusion to a ribbon, from which contact studs can be separated which have an edge-parallel directional structure.

Dependencies are inferred from the claim text.