Degussa Aktiengesellschaft

Willi Malikowski

Wolfgang Weise

Roger Wolmer

Peter Braumann

Andreas Koffler

Harald Krappitz

Dieter Kaufmann

Andreas Szulczyk

Alexander Voelcker

Joerg Beuers

Wolfgang Bohm

Wolfgang Boehm

Bohm Wolfgang

Ulrich Muerrle

Cadmium-free hard solders having working temperatures of less than 630&deg; C., which are easily workable and yield ductile soldered joints, are composed of 30 to 60% by weight of silver, 10 to 36% by weight of copper, 15 to 32% by weight of zinc, 0.5 to 7% by weight of gallium, 0.5 to 7% by weight of tin and 0 to 5% by weight of indium.

Cadmium-free silver alloy as low-melting brazing filler material

Sintered silver-iron material for electrical contacts, with properties comparable with those of silver-nickel materials, is obtained by using iron powder having more than 0.25% carbon by weight and microhardness higher than 200 HV 0.025 and sintering in a hydrogen-free protective gas.

Sintered silver-iron material for electrical contacts and process for

Silver-iron materials for electrical switching contacts with properties which come very close to those of silver-nickel materials formed of 0.5 to 4.5% by weight iron and 0.05 to 2% by weight of one or more of the oxides magnesium oxide, calcium oxide, yttrium oxide, lanthanum oxide, titanium oxide, zirconium oxide, hafnium oxide, cerium oxide, niobium oxide, tantalum oxide, chromium oxide, manganese oxide, iron oxide, zinc oxide, aluminum oxide, indium oxide, silicon oxide, and tin oxide, the balance being silver.

Silver-iron material for electrical switching contacts (I)

Silver-iron materials for electrical switching contacts with properties which come very close to those of silver-nickel materials formed of 4.6 to 15% by weight iron and 0.05 to 5% by weight of one or more of the oxides magnesium oxide, calcium oxide, yttrium oxide, lanthanum oxide, cerium oxide, chromium oxide, iron oxide, aluminum oxide, indium oxide, silicon oxide, and tin oxide, the balance being silver.

Silver-iron material for electrical switching contacts (II)

Silver-iron materials for electrical switching contacts with properties which come very close to those of silver-nickel materials formed of 0.5 to 20% by weight iron 0.5 to 5% by one or more of the elements rhenium, iridium, and ruthenium, and 0.05 to 2% by weight of one or more of the oxides magnesium oxide, calcium oxide, yttrium oxide, lanthanum oxide, titanium oxide, zirconium oxide, hafnium oxide, cerium oxide, niobium oxide, tantalum oxide, chromium oxide, manganese oxide, iron oxide, zinc oxide, copper oxide, aluminum oxide, indium oxide, silicon oxide, and tin oxide, the balance being silver.

Silver-iron material for electrical switching contacts (III)

Cadmium-free brazing solders with working temperatures under 630.degree. C. containing 45 to 80 wt. % silver, 14 to 25 wt. % copper 10 to 25 wt. % gallium, 1 to 7 wt. % zinc and 0 to 5 wt. % indium and/or tin. The alloys have good cold workability and ductility.

Cadmium-free silver alloy brazing solder, method of using said solder,

When hard-substance parts are soldered onto steel bases, thermal stresses are produced between the hard substance and the steel. These stresses can be reduced by means of using a multilayer solder in which the middle layer consists of a precipitation-hardenable copper alloy or nickel alloy provided on both sides with a layer of a hard-solder alloy whose working temperature is at least 50.degree. C. below the melting point of the precipitation-hardenable copper alloy or nickel alloy. A tempering treatment at 250.degree. to 550.degree. C. is carried out after the soldering in order to achieve a precipitation hardening of the middle layer.

Method for soldering hard substances onto steels

Cadmium-free brazing solders with working temperatures under 630.degree. C. containing 45 to 80 wt. % silver, 5 to 13 wt. % copper, 10 to 25 wt. % gallium, 8 to 20 wt. % zinc, and 0 to 5 wt. % indium and/or tin.

Use of a cadmium-free silver alloy as brazing solder (III)

Solders for directly soldering together ceramic parts consisting essentially of 70 to 99% silver, 0.5 to 15% by weight indium or 0.5 to 10% by weight tin and 0.5 to 15% by weight titanium or zirconium, or mixtures thereof. These solders are very ductile, are workable at comparatively low temperatures and provide very firm bonding.

Direct bonding of ceramic parts by a silver alloy solder

To coat metallic or ceramic surfaces with hard substances by means of brazing, a powder mixture of 60 to 90% silver, 2 to 35% copper, 2 to 30% tin and/or indium and 2 to 20% titanium, zirconium, hafnium, chromium, vanadium, tantalum, niobium, titanium hydride, zirconium hydride and/or hafnium hydride together with an organic binder and then the hard-substance powder are deposited on the surface and heated to 900.degree. to 1200.degree. C. The particle sizes of the metallic powders must be less than the particle size of the hard-substance powder.

Method for coating surfaces with hard substances

There is described a contact material based on silver-tin oxide and additional metal oxide having a high working life, slight welding strength and low switching temperatures. Besides silver and tin oxide it contains 0.05 to 4% of molybdenum oxide and/or germanium oxide.

Material for electrical contacts

There is described a material for electrical contacts based on silver having 5 to 20 weight % tin oxide and 0.5 to 5 weight % tungsten oxide which has the welding strength reduced further without producing an increased switching temperature. The material contains additionally 0.1 to 5 weight % of bismuth oxide.

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Aschaffenburg, Germany

Willi Malikowski