Abstract: A rivet-shaped electrical contact for relay is used as a movable contact for the relay. The rivet-shaped electrical contact includes a heavy-load contact portion formed of a first silver-oxide type contact material; and a light-load contact portion formed of a second silver-oxide type contact material. The hardness of the first silver-oxide type contact material is set to be higher than that of the second silver-oxide type contact material.

Abstract: A method of manufacturing a composite contact in which a flange section with a large diameter at an end of a base part with a small diameter, the composite contact having: a contact section which is made from silver alloy into an upper-surface part of the flange section; and a leg section which is made from copper alloy by forming a large-diameter part so as to form a lower-surface part of the flange section is made integrally with the base part, having the steps of: a primary-forming process forging a copper-alloy wire and a silver-alloy wire having a smaller diameter than that of the copper-alloy wire in a hole of a forming die in a state of being butted to each other so as to form a primary-formed body including a silver-alloy part and a copper-alloy part so that the wires are bonded with each other.

Abstract: A rivet-shaped electrical contact for relay is used as a movable contact for the relay. The rivet-shaped electrical contact includes a heavy-load contact portion formed of a first silver-oxide type contact material; and a light-load contact portion formed of a second silver-oxide type contact material. The hardness of the first silver-oxide type contact material is set to be higher than that of the second silver-oxide type contact material.

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.

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.

Abstract: An electrode for an ignition distributor of an internal combustion engine is disclosed which is made of a copper-based sintered alloy. The alloy contains a copper matrix, and grains of Al.sub.2 O.sub.3 having an average grain size of 10 to 100 .mu.m. The Al.sub.2 O.sub.3 grains are dispersed uniformly in the copper matrix at a ratio of from 45 to 60 percent by surface area as measured in an arbitrary cross-section. The electrode of this construction exhibits very low capacitive-discharge current peaks and starting voltages, and hence the generation of radio wave noise can be substantially eliminated.