Patent ID: 8187395
Filing Date: 2012-05-29
Classification: B22F,C22C,H01H

Abstract:
1. An electrical contact having high electrical conductivity for a compact electromagnetic relay, comprising: an internally oxidized and heat treated silver-oxide material which is prepared by subjecting an Ag alloy having a composition consisting essentially of, by weight, 5.1 to 9% Sn, 1.5 to 5% In, and 0.05 to 0.8% Te with the balance being Ag and unavoidable impurities, to an internal oxidation treatment and then subjecting to a heat treatment for diffusion, aggregation, and growth of precipitated oxides; wherein the internal oxidation of the Ag alloy produces a metallographic structure such that ultra-fine grains of Sn-based oxides and In-based oxides are dispersed and distributed in an Ag matrix, the heat treatment of the internally oxidized silver oxide material changes the metallographic structure such that coarse grains of composite oxides are formed as a result of coarsening of the ultra-fine grains of Sn-based oxides and the ultra-fine grains of In-based oxides, which are precipitated by the internal oxidation treatment, by the heat treatment for diffusion, aggregation, and growth of the precipitated oxides, and the heat treatment is conducted at a temperature ranging from 900° C. to 960° C. in an air atmosphere here for between 10 to 20 hours.