Electrical contact having high electrical conductivity made of internally oxidized silver-oxide material for compact electromagnetic relay

Abstract

Disclosed is an electrical contact having high electrical conductivity for a compact electromagnetic relay including an internally oxidized 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 0.005 to 0.06% Bi, 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 internally oxidized silver-oxide material has a metallographic structure such that coarse grains of composite oxides are dispersed and distributed in an Ag matrix, the coarse grains of composite oxides being formed as a result of coarsening of ultra-fine grains of Sn-based oxides and 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.