Material for electrical contacts consisting of silver@ or silver@-alloy matrix - incorporate tin oxide and other oxide(s) and carbide(s), has longer service life but is less brittle than other materials

摘要

Material used in the mfr. of electrical contacts consists of a predominantly Ag-contg. alloy matrix with regions of Sn oxide and other oxides and/or carbides. Other oxides and carbides are contained in the Sn oxide regions and/or in the boundary regions beteen Sn oxide and the Ag matrix. The total content of other oxides and carbides corresp. to 40 wt.% of Sn oxide content. Other oxides and carbides are those of Mo, W, Bi, Sb, Ge, V, Cu, or In. The Ag matrix contains none of the named other oxides and carbides (apart from possible soluble cpds.). The material is produced by mixing powdered Ag or Ag-alloy with a powder contg. Sn oxide plus other oxides/carbides, compressing and then sintering. Total material content of Sn oxides plus other oxides/carbides is 5-20 wt.%, pref. 8-15 wt.%. The concn. of other oxides/carbides in the Sn oxide regions (w.r.t. total Sn oxide content) is min. 0.01 wt.% and max. 10 wt.%, pref. 5 wt.%, esp. 2.5 wt.%, the most advantageous concn. being 0.1-1.5 wt.%. The Sn oxide regions in the material are less than 100 microns, pref. less than 10 microns, but not less than 0.5 microns in dia. Sn can be completely or partially replaced by Zn. ADVANTAGE - The material exhibits similar thermal behaviour to other contact materials, but is less brittle and has an increased service life.