Specialized metallurgical processes – compositions for use therei – Compositions – Consolidated metal powder compositions
Patent
1996-02-23
1998-08-18
Jenkins, Daniel J.
Specialized metallurgical processes, compositions for use therei
Compositions
Consolidated metal powder compositions
75234, 75247, 419 21, 419 38, 419 41, 419 53, B22F 316, C22C 105, C22C 506
Patent
active
057960178
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a contact material based on silver, there being present, in addition to silver, iron oxide as the main effective component and at least one further effective component. The invention also relates to the use of such a contact material in a switching device in power engineering and to the associated process for preparing the contact material.
Known contact materials for contact pieces in low-voltage switching devices in power engineering, e.g. in circuit breakers and in D.C. contactors, motor contactors and contactor relays include those, on the one hand, of the system silver-metal (AgMe) and, on the other hand, of the system silver-metal oxide (AgMeO). Representatives of the first system are, for example, silver-nickel (AgNi) or silver-iron (AgFe); representatives of the second system are, in particular, silver-cadmium oxide (AgCdO) and silver-tin oxide (AgSnO.sub.2). Further metal oxides such as, in particular, bismuth oxide (Bi.sub.2 O.sub.3), copper oxide (CuO) and/or tantalum oxide (Ta.sub.2 O.sub.5) may also be added.
The practical suitability of a contact material based on silver-metal or silver-metal oxide is determined by the so-called electrical "contact property spectrum". Important parameters in this context include the lifetime number of make-break operations on the one hand, which is determined by the erosion of the contact piece, and the so-called temperature rise on the other hand, i.e. the contact heating at the contact bridge and at the terminals which essentially results from the electrical resistance of the said contact construction. Also important are a sufficiently low welding tendency of the contact pieces and adequate corrosion resistance. For it should be noted that, owing to long-term corrosion of the material in air-break switching devices the switching properties may change over time.
DE-A-1 608 211 discloses an electrical contact material of the system silver-metal oxide which, in addition to cadmium or tin oxide, may also contain iron oxide. Further, DE-C-38 16 895 discloses the use of a silver-iron material containing from 3 to 30% by weight of iron and containing one or more of the additives manganese, copper, zinc, antimony, bismuth oxide, molybdenum oxide, tungsten oxide, chromium nitride in amounts of, in total, from 0.05 to 5% by weight, the remainder being silver, for electrical contacts. In addition, DE-A-39 11 904 discloses a powder-metallurgical process for preparing a semi-finished product for electrical contacts from a silver-based composite material containing iron, in which from 5 to 50% by weight of iron as the first minor constituent and from 0 to 5% by weight of a second minor constituent are used. The second constituent contains one or more substances from the group comprising the metals titanium, zirconium, niobium, tantalum, molybdenum, manganese, copper and zinc as well as their oxides and their carbides. The iron in elemental form is obtained in the process by chemical precipitation, in particular. Finally, JP-A-1/055345 discloses a material of the type mentioned at the outset, which is composed of from 0.5 to 20% by weight of iron oxide particles dispersed in a silver matrix, in which material a portion of the iron oxide is replaced by at least one of the oxides of nickel, cobalt, chromium, molybdenum, tungsten, cadmium, zinc, antimone, tin, bismuth, indium, lead, manganese, beryllium, calcium, magnesium or copper. The contact pieces manufactured therefrom are claimed to be distinguished, for use in switches, by good mechanical properties and high arc resistance.
WO-A-92/22080 discloses a contact material in which, in addition to the iron oxide, rhenium oxide and/or bismuth zirconate and/or boron oxide and/or zirconium oxide are present as a further effective component, the iron oxide being present as the main component in percentages by weight between 1 and 50%, and the minor components being present in percentages by weight between 0.01 and 5%. The iron oxide may here have the constitution Fe.sub.2 O.
REFERENCES:
patent: 2200855 (1940-05-01), Ruben
patent: 2572662 (1951-10-01), Richardson et al.
patent: 2985532 (1961-05-01), Simon
patent: 3922236 (1975-11-01), Douglas et al.
patent: 4426356 (1984-01-01), Nair
patent: 4764227 (1988-08-01), Rothregel et al.
patent: 4777335 (1988-10-01), Okutomi et al.
patent: 5198015 (1993-03-01), Tsuji et al.
patent: 5258052 (1993-11-01), Bevington
patent: 5279638 (1994-01-01), Asada et al.
patent: 5429656 (1995-07-01), Hauner et al.
patent: 5591926 (1997-01-01), Inada et al.
patent: 5610347 (1997-03-01), Behrens et al.
Jenkins Daniel J.
Siemens Aktiengesellschaft
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