Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H1/00—Contacts
  • H01H1/02—Contacts characterised by the material thereof
  • H01H1/021—Composite material
  • H01H1/023—Composite material having a noble metal as the basic material
  • H01H1/0237—Composite material having a noble metal as the basic material and containing oxides
  • H01H1/02372—Composite material having a noble metal as the basic material and containing oxides containing as major components one or more oxides of the following elements only: Cd, Sn, Zn, In, Bi, Sb or Te
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H1/00—Contacts
  • H01H1/02—Contacts characterised by the material thereof
  • H01H1/021—Composite material
  • H01H1/023—Composite material having a noble metal as the basic material
  • H01H1/0237—Composite material having a noble metal as the basic material and containing oxides
  • H01H1/02372—Composite material having a noble metal as the basic material and containing oxides containing as major components one or more oxides of the following elements only: Cd, Sn, Zn, In, Bi, Sb or Te
  • H01H1/02376—Composite material having a noble metal as the basic material and containing oxides containing as major components one or more oxides of the following elements only: Cd, Sn, Zn, In, Bi, Sb or Te containing as major component SnO2
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/05—Mixtures of metal powder with non-metallic powder
  • C22C1/059—Making alloys comprising less than 5% by weight of dispersed reinforcing phases
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
  • C22C32/001—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides
  • C22C32/0015—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides with only single oxides as main non-metallic constituents
  • C22C32/0021—Matrix based on noble metals, Cu or alloys thereof

Definitions

• the invention relates to a powder-metallurgically produced sintered material based on silver-tin oxide with additions of indium oxide and bismuth oxide for electrical contacts for switching nominal currents between 20 and 100 amperes and a method for the production thereof.
• Silver / metal and silver / metal oxide composites have proven themselves for the production of electrical contacts in low-voltage switchgear.
• the most common silver / metal composite is silver / nickel, the main application of which is lower currents.
• silver-cadmium oxide was used almost exclusively for high currents.
• tin oxide has established itself as an alternative to cadmium oxide in many areas.
• the silver-tin oxide composite shows a significantly lower burn-up rate than silver-cadmium oxide, which leads to a longer service life in the switchgear.
• the disadvantage of AgSn0 2 is that it tends to form a covering layer and thus to higher temperatures in the switchgear. With certain additives, such as WO 3 or MoO 3 , this problem could be dealt with. These materials have proven themselves extremely well in switching devices that have to withstand high thermal loads. With these additives, AgSnO 2 has proven itself particularly well in switchgear with nominal currents of more than 100 amps and under so-called AC4 load. With less Switching currents, however, the service life of these materials is relatively short.
• the AgSnO 2 WO 3 / MoO 3 material is manufactured by powder metallurgy using extrusion technology.
• the powder metallurgical production has the advantage that additives of any type and amount can be used. This allows the material to be specifically optimized for certain properties, such as welding force or heating.
• the combination of powder metallurgy with extrusion technology allows a particularly high level of economy in the manufacture of the contact pieces.
• An internally oxidized AgSnO 2 / In 2 O 3 material is also used.
• This material described in DE-OS 24 28 147, contains 5-10% SnO 2 and 1-6% In 2 O 3 .
• Internally oxidized materials have the disadvantage that the additives have to be selected with regard to the oxidation kinetics of the materials. A targeted change in the concentrations of the oxide additives to influence certain switching properties is often not possible due to the oxidation kinetics.
• the AgSnO 2 In 2 O 3 has the disadvantage, however, that it leads to high excess temperatures when switching.
• DE-OS 27 54 335 describes a contact material which contains 1.6 to 6.5 Bi 2 O 3 and 0.1 to 7.5 SnO 2 in addition to silver. This material can be produced both by internal oxidation and by powder metallurgy. Such high Bi 2 O 3 contents, however, lead to embrittlement, so that the material can only be produced by single sintering, but not by the more economical extrusion technology.
• the powder metallurgical production of contact materials based on silver-tin oxide by mixing the powders, cold isostatic pressing, sintering and extrusion into semi-finished products is known, for example, from DE-OS 43 19 137 and DE-OS 43 31 526.
• a process for its production should be found that is economical and brings further improvements for the material.
• This object is achieved in that it consists of 3.2 to 19.9% by weight of tin oxide, 0.05 to 0.4% by weight of indium oxiodine and bismuth oxide, the rest being silver.
• this material In the current range from 20 to 100 amperes, this material has an excellent service life with excess temperatures that are well below 100 ° C.
• Particularly good material properties can be achieved in the manufacture of the material by mixing the powders, cold isostatic pressing of the powder mixture, sintering at temperatures from 500 to 940 ° C and extrusion into wires or profiles if more than 60% by weight of the tin oxide powder used before mixing with the silver powder and the other oxide powders have a particle size of more than 1 ⁇ m.
• tin oxide normally has a particle size of less than 1 ⁇ m, more than 70% by weight, it is necessary to coarsen this powder.
• The is preferably done by annealing the tin oxide powder or the tin oxide powder together with the bismuth oxide powder at temperatures from 700 to 1400 ° C. until more than 60% by weight of the tin oxide or the mixed oxide powder have a particle size of more than 1 ⁇ m.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Composite Materials (AREA)
• Dispersion Chemistry (AREA)
• Contacts (AREA)
• Powder Metallurgy (AREA)
• Manufacture Of Alloys Or Alloy Compounds (AREA)
• Manufacture Of Switches (AREA)

Applications Claiming Priority (2)

Publications (2)

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Citations (4)

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• 1995
  • 1995-02-01 DE DE19503182A patent/DE19503182C1/de not_active Expired - Fee Related
• 1996
  • 1996-01-19 TW TW085100636A patent/TW460595B/zh active
  • 1996-01-20 DE DE59603939T patent/DE59603939D1/de not_active Expired - Lifetime
  • 1996-01-20 ES ES96100814T patent/ES2141979T3/es not_active Expired - Lifetime
  • 1996-01-20 EP EP96100814A patent/EP0725154B1/fr not_active Expired - Lifetime
  • 1996-01-31 BR BR9600289A patent/BR9600289A/pt not_active IP Right Cessation
  • 1996-01-31 US US08/594,143 patent/US5798468A/en not_active Expired - Fee Related
  • 1996-01-31 CN CN961013427A patent/CN1065002C/zh not_active Expired - Fee Related
  • 1996-01-31 KR KR1019960002278A patent/KR960031028A/ko not_active Application Discontinuation
  • 1996-02-01 JP JP8016749A patent/JPH08239723A/ja active Pending
  • 1996-02-01 SG SG1996000788A patent/SG70549A1/en unknown
  • 1996-02-01 RU RU96102037A patent/RU2144093C1/ru not_active IP Right Cessation

Patent Citations (4)

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