Abstract: Electrical contact materials made from Ag-Sn-In system alloys which have been internally oxidized. A substratum or base part of the materials is internally oxidized after having been clad with a thin layer of alloys of the same alloy system, concentration of solute elements of which is, however, smaller than that of the substratum alloys, so that no segregation of the solute metal elements shall be produced within the substratum alloys. Electrical contact resistance and consequent temperature raise of the internally oxidized materials under operation are considerably lowered.

Abstract: Internal oxidation method of Ag alloys for electrical contact materials and the like, in which vacant lattice points or voids which form paths of oxygen and oxidation nuclei in the course of internal oxidation, are produced innumerably and on an atomic scale by having the alloys absorbed with hydrogen, helium, nitrogen, or neutron, or by having the alloys subjected to a reduction atmosphere of a decreased pressure or to vacuum, respectively prior to the internal oxidation.In the course of internal oxidation, solute metals fill in the voids and precipitate as oxides at the innumerable oxide nuclei on an atomic scale, without diffusing about much but only to such extent that they reach most adjacent voids, and consequently without any segregation and depletion thereof.

Abstract: In order to overlay a stainless steel material for decorative articles and ornaments with a precious metal alloy, a comparatively thin layer of said alloy or a plurality of constituent thin layers of said alloy are overlaid on a selected surface of said stainless steel and heated to a temperature higher than 800.degree. C. for the diffusion bonding of said layer or layers to the stainless body and for annealing of said body, and thereafter another thicker layer or constituent layers of a precious metal alloy are overlaid on the stainless steel material with or without heating said second-mentioned layer or layers.

Abstract: A tri-metallic electrical contact consisting of a head wire piece and a base wire piece which abut to an intermediate piece at its opposite ends, is produced by cold press operations performed by first and second die and punch sets. The first die and punch set causes plastic deformation of approximately only a half part of the aligned wire pieces, while keeping another half part of these pieces not deformed. The second die and punch set imparts, subsequent to, and independently from, the cold press operation performed by the first die and punch set, plastic deformation to the other half part of the pieces, whereby the abutting surfaces of the three wires are prevented from sliding movements laterally relative to each other during the cold press operations, and whereby irregular or insufficient deformation of the wires due to the differences of yield points of the wires is prevented.

Abstract: Ag-SnO alloy contact materials of such dimensions which are hard to achieve internal oxidation without producing depleted cores due to lack of tin oxides, are produced by metallurgically integrating pieces of said alloy material, said pieces being of such dimensions that they are easily internally oxidized without any depleted cores. Integration consists of congregating or assemblying said pieces by kneading under pressure and at a temperature higher than 700.degree. C. into a mass in which said pieces coalesce to each other without any distinctive silver interface thereamong, and through which tin oxides are uniformly dispersed substantially without any grain boundaries.

Abstract: Internally oxidized Ag-Sn-Bi alloy electrical contact materials are improved of their tensile strength and rate of consumption by the addition of 0.1-8.5 weight % of Cu, whereby they present stable contact resistance and less amount of consumption. The alloy may comprise 0.01-0.5 weight % of one or more elements of the iron family.

Abstract: A tri-metallic electrical contact consisting of a head wire piece and a base wire piece which abut to an intermediate piece at its opposite ends, is produced by cold press operations performed by first and second die and punch sets. The first die and punch set causes plastic deformation of approximately only a half part of the aligned wire pieces, while keeping another half part of these pieces not deformed. The second die and punch set imparts, subsequent to, and independently from, the cold press operation performed by the first die and punch set, plastic deformation to the other half part of the pieces, whereby the abutting surfaces of the three wires are prevented from sliding movements laterally relative to each other during the cold press operations, and whereby irregular or insufficient deformation of the wires due to the differences of yield points of the wires is prevented.

Abstract: Internally oxidized Ag-Sn alloy electrical contact materials have their electrical characteristics improved by being compounded with other Ag alloys containing metal elements which are in solid solution with Ag and are internally oxidizable. Compounds obtained in accordance with this invention include microscopic silver grain matrices containing Sn oxides and other silver grain matrices which contain metallic oxides of the said other Ag alloys and are intercoalesced with each other and with the first mentioned silver grain matrices, and present macroscopically improved electric characteristics as if they were a single alloy.

Abstract: An electrical contact material obtained through internally oxidizing a silver alloy which is the solid solution with 3 to 11 weight percent of tin and other solute metal element(s). The alloy material is improved of its contact resistance by diffusing into the silver matrix 0.1 to 5 weight percent of metals having a decomposition and sublimation temperature lower than the melting point of silver and then by internally oxidizing the material.

Abstract: An alloy for composite electrical contact materials which is composed of 5 to 10 weight percent of tin and 1.0 to 6 weight percent of indium, the balance being silver, said alloy being subjected to an internal oxidation. The alloy may contain, when added by one or more other solute metal elements selected from zinc, antimony, lead and bismuth, as much as 6 to 15 weight percent of tin and said other solute metal elements in total in which the latter are less than 30 percent of the former. The alloy may also comprise up to 0.5 weight percent of ferrous or alkali earth metals.

Abstract: An electrical contact material obtained through internally oxidizing a silver alloy which is the solid solution with 5 to 20 weight percent of one or more of the solute metal elements selected from tin, zinc and antimony and which contains 0.01 to 1.0% weight percent of bismuth. The silver alloy may also include up to 0.5 weight percent of ferrous metal or metals.