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
• • 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
  • H01H2001/02378—Composite material having a noble metal as the basic material and containing oxides containing iron-oxide as major component

Definitions

• Silver-based contact material use of such Contact material in a switching device in energy technology and method for producing the contact material
• the invention relates to a contact material based on silver-iron oxide (AgFe 2 O 3 / Fe 3 O 4 ), the iron oxide being the main active component in mass fractions of 3 to 20% and at least one further metal oxide being present as the secondary component.
• the invention relates to the use of such a contact material in a switching device in power engineering and to the associated method for producing the contact material.
• contact materials are known on the one hand of the silver-metal system (AgMe) and on the other hand of the silver-metal oxide (AgmeO) system.
• 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 2 ).
• metal oxides such as, in particular, bismuth oxide (Bi 2 O 3 ), copper oxide (CuO) and / or tantalum oxide (Ta 2 O 5 ).
• bismuth oxide Bi 2 O 3
• CuO copper oxide
• Ta 2 O 5 tantalum oxide
• DE-A 26 59 012 mentions a number of metals which should be suitable as embeddings for silver-containing contact materials.
• the practical usability of a contact material Silver-metal or silver-metal oxide base is made by the so-called electrical "contact property spectrum" determined. Relevant parameters are the lifespan switching number on the one hand, by the erosion of the contact piece is determined, and the so-called overtemperature on the other hand, i.e. the contact heating at the contact bridge and at the connections, which essentially result from the electrical resistance of the mentioned contact structure results. A sufficiently low tendency to sweat is also important of the contact pieces and sufficient corrosion resistance. Because it should be noted that long-term corrosion of the material in air switchgear Switching properties can change over time.
• a contact material known from silver metal oxide in which as metal oxides at least copper oxide as the main active component and at least one of the components zinc oxide, tin oxide, antimony oxide as Auxiliary components are present.
• the material inter alia also in parts of yttrium oxide or lanthanum oxide have from 0.005 to 2% by weight.
• JP-A-1/055345 a material of the type mentioned is known, that of a silver matrix with 0.5 to 20 percent by weight distribute iron oxide particles, in which a part of the Iron oxide by at least one of the oxides of nickel, Cobalt, chrome, molybdenum, tungsten, cadmium, zinc, antimony, Tin, bismuth, indium, lead, manganese, beryllium, calcium, Magnesium or copper is replaced.
• Contact pieces should be used for switches good mechanical properties and high arc resistance award.
• W0-A-92/22080 has already proposed a contact material in which rhenium oxide and / or bismuth zirconate and / or boron oxide and / or zirconium oxide are present in addition to the iron oxide as a further active component, the iron oxide as the main component in proportions by weight between 1 and 50 % and the secondary components are present in mass fractions between 0.01 and 5%.
• the iron oxide can have the constitution Fe 2 O 3 or Fe 3 O 4 , but optionally also a mixed form.
• the object is achieved in that the Subcomponent an oxide of an element of the third subgroup of the periodic table and in mass fractions of 0.1 up to 10%.
• the elements of the sixth subgroup of the Periodic table contains.
• the iron oxide as the main active component is preferably present either in mass fractions of 7.5 to 15% or in mass fractions of 4 to 7.5%, while the further oxide preferably has a mass fraction between 0.5 to 2%.
• the elements scandium (Sc), yttrium (Y) and lanthanum (La) with the other lantanides are suitable as elements for the further active component from the third subgroup of the periodic table.
• the further active component is yttrium oxide (Y 2 O 3 ).
• a material with the composition Ag / Fe 2 O 3 1O / Y 2 O 3 1 fulfills the requirements particularly well.
• ferrotungstate FeWO 4
• FeWO 4 ferrotungstate
• a material with the composition Ag / Fe 2 O 3 9 / Y 2 O 3 1 / FeWO 4 0.5 has proven particularly useful.
• the new contact materials are produced according to the invention in that initially silver powder and iron oxide powder are mixed together in a predetermined ratio, that this mixture is mixed with the other metal oxides and that then the further processing by alternating sintering and pressing.
• the table shows measured values for the overtemperature of the new one Materials, each on the contact bridge of the switching device was measured as the maximum and average bridge temperatures as well as measured values for the combustion behavior specified.
• the table contains a typical one Example with a meaningful composition of the invention Contact material.
• the measurements were taken directly a contact bridge of the 15KW test contactor with two each Contact pieces. The measurement results are described below in individual received.
• Example 1 Ag / Fe 2 O 3 1O / Y 2 O 3 1 contact material
• a material of the composition Ag / Fe 2 O 3 1O / Y 2 O 3 1 is to be produced.
• separate silver powder and iron oxide powder are first mixed in a predetermined ratio, and 1m% yttrium oxide powder is added to this powder mixture.
• the further production takes place in a known manner by alternating sintering and pressing under predetermined boundary conditions.
• the contact pieces are manufactured either by an extrusion technique or by a molding technique. In both cases, the backs are already provided with a solderable and / or weldable silver layer during manufacture to ensure a secure connection technology.
• the contact pieces of the constitution Ag / Fe 2 O 3 / Y 2 O 3 thus produced were subjected to comparative tests with known contact materials in the contactor specified, the results of which are shown in the table.
• the table first shows an AgNi20 contact material with the known good properties both with regard to the bridge temperature and with regard to the erosion. These values deteriorate significantly in the case of AgFe 2 O 3 contact materials with only iron oxide to replace the nickel, the maximum temperatures observed for individual switching bridges being inadmissibly high. An increase proportional to the oxide content is observed, while the burn-off decreases as expected.
• Zirconium oxide (ZrO 2 ) in particular has proven itself, with the results listed in the table.
• a low maximum bridge temperature and an excellent average bridge temperature are found here with a low iron oxide content, in particular with less than about 7.5% by weight of Fe 2 O 3 , although the burnup is unsatisfactory. The latter only drops at higher iron oxide contents, ie from about 7.5% by weight Fe 2 O 3 , although a deterioration in the temperature behavior can be observed.
• the table also shows that the temperature behavior especially by adding yttrium oxide in is surprisingly improved without the Burning deteriorated considerably.
• the yttrium oxide content can in the range between 0.1 and 10% by mass lie.
• the temperature behavior of the material Ag / Fe 2 O 3 1O / Y 2 O 3 1 in particular is directly comparable with that of AgNi10.
• the burn-up is now significantly lower than the burn-up in the known materials. For example, with a switching number of 50,000, a burn-up was only about 20% above the silver-nickel, while it is significantly higher with the other substitute materials.
• the other chemical elements of the third subgroup of the periodic table may also be considered as secondary components for an AgFe 2 O 3 material.
• Example 2 Ag / Fe 2 O 3 9 / Y 2 O 3 1 / FeWO 4 0.5 contact material
• this material separate is first Silver powder and iron oxide powder in the specified ratio mixed and this powder mixture 1 mass% yttrium oxide powder and 0.5% by mass of iron tungstate powder.
• the further one Manufactured in a known manner by alternating Sintering and pressing under specified conditions.
• Contact pieces are made from this material either by an extrusion technique or a molding technique. In both cases, the backs are made during manufacture the contact pieces with a solderable and / or weldable Silver layer to ensure a secure connection technology of the contact pieces.
• Example 2 it was found that the material according to Example 2 not only achieves the favorable temperature properties of the sintered contact materials of the constitution Ag / Fe 2 O 3 / Y 2 O 3 already proposed in Example 1, but also in particular improves the welding and short-circuit behavior . This material is therefore particularly suitable for use in circuit breakers.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Composite Materials (AREA)
• Materials Engineering (AREA)
• Contacts (AREA)
• Manufacture Of Switches (AREA)

Applications Claiming Priority (5)

Publications (2)

Family

ID=25928842

Family Applications (1)

Country Status (8)

Families Citing this family (10)

Family Cites Families (17)

• 1994
  • 1994-08-16 WO PCT/DE1994/000935 patent/WO1995006321A1/de active IP Right Grant
  • 1994-08-16 EP EP94923654A patent/EP0715765B1/de not_active Expired - Lifetime
  • 1994-08-16 DE DE59405126T patent/DE59405126D1/de not_active Expired - Fee Related
  • 1994-08-16 CN CN94193884A patent/CN1056012C/zh not_active Expired - Fee Related
  • 1994-08-16 US US08/601,059 patent/US5796017A/en not_active Expired - Fee Related
  • 1994-08-16 JP JP50725795A patent/JP3676365B2/ja not_active Expired - Fee Related
  • 1994-08-16 BR BR9407450A patent/BR9407450A/pt not_active Application Discontinuation
  • 1994-08-16 ES ES94923654T patent/ES2113671T3/es not_active Expired - Lifetime
• 2005
  • 2005-02-02 JP JP2005026537A patent/JP2005166683A/ja active Pending

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