EP0916146B1 - Method of producing a product from a silver-based contact material, contact material and product produced therefrom - Google Patents

Method of producing a product from a silver-based contact material, contact material and product produced therefrom Download PDF

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Publication number
EP0916146B1
EP0916146B1 EP97935481A EP97935481A EP0916146B1 EP 0916146 B1 EP0916146 B1 EP 0916146B1 EP 97935481 A EP97935481 A EP 97935481A EP 97935481 A EP97935481 A EP 97935481A EP 0916146 B1 EP0916146 B1 EP 0916146B1
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Prior art keywords
iron
oxide
contact material
silver
product
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EP97935481A
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German (de)
French (fr)
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EP0916146A1 (en
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Franz Hauner
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Metalor Technologies International SA
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Metalor Technologies International SA
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    • 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
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
    • 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

  • the invention relates to a method for producing a Product made of a contact material based on silver Iron oxide as the main active component.
  • the invention relates a contact material and a product from one such contact material, in particular a contact piece for a switching device of energy technology.
  • silver-based contact materials that contain certain active components have long proven themselves. Both metals and metal oxides are known as active components which have a favorable influence on the switching properties of the contact material.
  • the silver-based metallic contact materials are silver-nickel (AgNi) and silver-iron (AgFe). Silver-iron oxide (AgFe 2 O 3 ) may be mentioned in particular as a representative of the oxidic contact materials.
  • the practical usability of a contact material is determined by its electrical contact properties. authoritative The parameters are the lifespan number, the is determined by the erosion of the contact piece, the so-called Overtemperature resulting from contact heating the contact bridge and at the connections results in the tendency to weld and the corrosion resistance.
  • Silver-nickel contact materials in particular have good ones Switching properties, but it is disadvantageous that the during manufacture or during operation due to abrasion Nickel dust as well as that which forms as a switching product Nickel oxide harmful effects on the human organism can have.
  • a replacement material for silver-nickel contact materials is an oxidic contact material from DE-A-43 28 281 known on silver basis, which as the main active component iron oxide in proportions from 3% to 20% and as another Active component at least one oxide of an element of third subgroup of the periodic table in a mass fraction contains from 0.1% to 10%.
  • the use of Yttrium oxide as a further active component is used as particularly advantageous for the contact properties of such Contact material viewed.
  • DE-A-44 10 462 describes a silver-based contact material with iron oxide as the main active component.
  • iron oxide in addition to an oxide of an element of the third subgroup of the periodic table, in particular yttrium oxide, at least one metal oxide of an element of the 6th subgroup of the periodic table is added.
  • Iron tungstate (FeWO 4 ) in particular reduces contact heating and the tendency to weld and leads to a long service life of the contact material.
  • DE-A-41 17 311 is a contact material known on the basis of silver, which as the active components iron oxide in proportions between 1% and 50% and an oxide of one further chemical element in mass fractions between Contains 0.01% and 5%. It has been recognized that especially the temperature behavior of a silver-iron oxide contact material by adding rhenium oxide, bismuth zirconate, Boron oxide, zirconium oxide, molybdenum oxide or tungsten oxide can be influenced favorably.
  • a manufacturing process for a silver-based contact material with iron oxide as the main active component is from the DE-A-43 28 281, DE-A-41 17 311 and DE-A-44 10 462 are known, corresponding proportions of silver powder, iron oxide powder and powder to mix other active components and the resulting powder mixture powder metallurgically to a semi-finished product or to process it into a fitting.
  • Powders are all commercially available powders used.
  • the powder mixture is made by compression molding pressed into a molded part, which by sintering and if necessary, further pressing into a finished molding becomes.
  • the molded part can also be coated with a layer Pure silver for the safe connection of the contact piece with the Pad to be pressed by brazing.
  • the powder mixture is initially too a porous compact or ingot is pressed and / or sintered.
  • the compact or ingot is, if necessary, together with a Pure silver layer, extruded into one strand pressed, from which the fittings are separated and possibly undergo a subsequent treatment.
  • a disadvantage of mixing silver powder with commercial ones Oxide powders produced silver-iron oxide contact materials is their poor ductility. Such contact materials are poorly suited for the production of Rivets, especially rivets with a large head / shaft ratio. Since the rivet head is usually by a Compression deformation from a shaped piece in the form of a wire is formed, a high deformability of the used Material are required.
  • the invention has for its object a method for Manufacture of a product from a contact material excellent switching properties and one compared to the State of the art to provide significantly improved deformability.
  • Another object of the invention is such Contact material and a product, in particular in the form a rivet to indicate from the contact material, which is particularly suitable for use in energy technology.
  • this object is achieved by first forming a powder mixture of silver (Ag) and iron (Fe) in which the iron (Fe) is in the form of a powder an average grain size of greater than 1 ⁇ m is used, and then this powder mixture is further processed by powder metallurgy to give the shaped piece and the iron (Fe) is oxidized to iron oxide (Fe 2 O 3 / Fe 3 O 4 ).
  • the object is achieved according to the invention by a silver-based contact material with iron oxide as the main active component, which comprises silver and iron oxide (Fe 2 O 3 / Fe 3 O 4 ), the mean grain size of the oxide being greater than 1 ⁇ m, preferably greater than 3 ⁇ m is.
  • the invention is based on the knowledge that the deformability a silver-based contact material with iron oxide as the main active component essentially through the middle Grain size of the iron oxide particles determined in the silver matrix is.
  • the grain size of the iron oxide particles is from 1 ⁇ m to 10 ⁇ m such contact material with a large average grain size the iron oxide particles have a higher deformability as a contact material with a small average grain size.
  • iron powders are available whose average grain sizes are larger than 1 ⁇ m
  • the use of iron powder instead of iron oxide powder and subsequent oxidation of iron to iron oxide enables a contact material to be obtained in which the average grain size of the iron oxide particles is in a range of more than 1 ⁇ m.
  • the iron oxide can be pure Fe 2 O 3 or Fe 3 O 4 or a mixture of these oxides. Since no additional work step is necessary in comparison to conventional manufacturing methods, the method according to the invention is particularly inexpensive.
  • a product should be the one in any form Contact material can be understood.
  • a mere powder mixture or a loose compression of the powder mixture, the iron has not yet been oxidized to iron oxide is not a product in this sense.
  • the mentioned ingot, in which iron has been oxidized to iron oxide or a finished one Fitting, however, are such products.
  • iron in Form of a powder with an average grain size of larger than 3 ⁇ m is used.
  • the oxidation of the iron advantageously takes place in the Powder mixture because of the increasing compression of the powder mixture a complete one in subsequent steps Oxidation is difficult.
  • the oxidation is too possible in a blank of the product, which is still one has sufficiently high porosity or gas permeability.
  • a blank is, for example, that in extrusion technology to be provided ingot, which subsequently becomes a strand is pressed.
  • Such a blank can also be used in the Molding technology manufactured preliminary product for a molding his.
  • the iron is treated in a heat treatment oxidizing atmosphere, preferably in air or oxygen oxidized.
  • the heat treatment is advantageously carried out at a temperature of 500 ° C to 1000 ° C, preferably at about 700 ° C.
  • zirconium oxide ZrO 2
  • rhenium oxide ReO 2 / ReO 3 / Re 2 O 7
  • the rhenium oxide can be pure ReO 2 , ReO 3 or Re 2 O 7 , but it can also be present as a mixture of the oxides mentioned.
  • These metal oxides are known in particular to favorably influence, ie reduce, the excess temperature which results from the contact heating and essentially depends on the electrical resistance of the contact bridge.
  • the switching properties of the contact material can be favorably by adding more metals to the powder mixture and / or further metal oxides are added.
  • Cheap for the switching properties are, for example, metals from the 3rd and 6th subgroup of the periodic table and / or Oxides of these metals.
  • the contact material has favorable switching properties if the iron oxide (Fe 2 O 3 / Fe 3 O 4 ) is present in a mass fraction between 1% and 50% and an oxide of the further metal in a mass fraction between 0.01% and 5%.
  • the object regarding the product is solved by a Product made of a silver-based contact material, which Silver and iron oxide as the main active component, wherein the mean grain size of the iron oxide is greater than 1 ⁇ m, preferably is larger than 3 ⁇ m.
  • The is particularly suitable Contact material especially for a contact piece in the form of a Rivet for a switching device in energy technology, e.g. a low voltage switch.

Abstract

The invention concerns a method of producing a product from a silver-based contact material. According to this method, first, a powder mixture of silver and iron is formed in which the iron is used in the form of a powder having a mean grain size of more than 1 νm. This mixture is then further processed in a powder-metallurgical manner to form the product, the iron being oxidized to form iron-oxide. This method produces a silver- and iron-oxide contact material whose iron-oxide particles have a larger mean grain size than the prior art contact materials. A contact material of this type displays high ductility although its good switching properties remain unchanged. It is suitable in particular for use as a contact part in the form of a rivet for a power engineering switching device.

Description

Die Erfindung betrifft ein Verfahren zur Herstellung eines Erzeugnisses aus einem Kontaktwerkstoff auf Silberbasis mit Eisenoxid als Hauptwirkkomponente. Die Erfindung betrifft weiter einen Kontaktwerkstoff sowie ein Erzeugnis aus einem solchen Kontaktwerkstoff, insbesondere ein Kontaktstück für ein Schaltgerät der Energietechnik.The invention relates to a method for producing a Product made of a contact material based on silver Iron oxide as the main active component. The invention relates a contact material and a product from one such contact material, in particular a contact piece for a switching device of energy technology.

Für ein Kontaktstück in einem Schaltgerät der Energietechnik, z.B. in einem Leistungsschalter sowie in einem Gleichstrom-, Motor- oder Hilfsschütz, haben sich Kontaktwerkstoffe auf Silberbasis, die bestimmte Wirkkomponenten enthalten, seit langem bewährt. Als Wirkkomponenten, welche die Schalteigenschaften des Kontaktwerkstoffes günstig beeinflussen, sind sowohl Metalle als auch Metalloxide bekannt. Vertreter der metallischen Kontaktwerkstoffe auf Silberbasis sind Silber-Nickel (AgNi) und Silber-Eisen (AgFe). Als Vertreter der oxidischen Kontaktwerkstoffe sei insbesondere Silber-Eisenoxid (AgFe2O3) genannt.For a contact piece in a power engineering switchgear, for example in a circuit breaker as well as in a direct current, motor or auxiliary contactor, silver-based contact materials that contain certain active components have long proven themselves. Both metals and metal oxides are known as active components which have a favorable influence on the switching properties of the contact material. Representatives of the silver-based metallic contact materials are silver-nickel (AgNi) and silver-iron (AgFe). Silver-iron oxide (AgFe 2 O 3 ) may be mentioned in particular as a representative of the oxidic contact materials.

Die praktische Vewendbarkeit eines Kontaktwerkstoffes wird durch seine elektrischen Kontakteigenschaften bestimmt. Maßgebliche Kenngrößen dabei sind die Lebensdauerschaltzahl, die durch den Abbrand des Kontaktstückes bestimmt wird, die sogenannte Übertemperatur, die sich aus der Kontakterwärmung an der Kontaktbrücke und an den Anschlüssen ergibt, die Verschweißneigung und die Korrosionsbeständigkeit.The practical usability of a contact material is determined by its electrical contact properties. authoritative The parameters are the lifespan number, the is determined by the erosion of the contact piece, the so-called Overtemperature resulting from contact heating the contact bridge and at the connections results in the tendency to weld and the corrosion resistance.

Zur Messung der Schalteigenschaften eines Kontaktwerkstoffes wird üblicherweise ein in Z.f. Werkstofftechnik/J. of materials technologies 7 (1976) 381 bis 389, beschriebener Prüfschalter herangezogen, in den jeweils ein Kontaktstück aus dem Kontaktwerkstoff eingesetzt wird.For measuring the switching properties of a contact material is usually a in Z.f. Materials Engineering / J. of materials technologies 7 (1976) 381 to 389 Test switch used, in each of which a contact piece from the contact material is used.

Besonders Silber-Nickel-Kontaktwerkstoffe besitzen gute Schalteigenschaften, jedoch ist nachteilig, daß der sich bei der Herstellung oder während des Betriebs durch Abrieb bildende Nickelstaub sowie das sich als Schaltprodukt bildende Nickeloxid schädliche Auswirkungen auf den menschlichen Organismus haben können.Silver-nickel contact materials in particular have good ones Switching properties, but it is disadvantageous that the during manufacture or during operation due to abrasion Nickel dust as well as that which forms as a switching product Nickel oxide harmful effects on the human organism can have.

Als ein Ersatzwerkstoff für Silber-Nickel-Kontaktwerkstoffe ist aus der DE-A-43 28 281 ein oxidischer Kontaktwerkstoff auf Silberbasis bekannt, welcher als Hauptwirkkomponente Eisenoxid in Massenanteilen von 3 % bis 20 % und als eine weitere Wirkkomponente zumindest ein Oxid eines Elementes der dritten Nebengruppe des Periodensystems in einem Massenanteil von 0,1 % bis 10 % enthält. Insbesondere die Verwendung von Yttriumoxid als eine weitere Wirkkomponente wird dabei als besonders vorteilhaft für die Kontakteigenschaften eines derartigen Kontaktwerkstoffes angesehen.As a replacement material for silver-nickel contact materials is an oxidic contact material from DE-A-43 28 281 known on silver basis, which as the main active component iron oxide in proportions from 3% to 20% and as another Active component at least one oxide of an element of third subgroup of the periodic table in a mass fraction contains from 0.1% to 10%. In particular, the use of Yttrium oxide as a further active component is used as particularly advantageous for the contact properties of such Contact material viewed.

Ebenso ist in der DE-A-44 10 462 ein Kontaktwerkstoff auf Silberbasis mit Eisenoxid als Hauptwirkkomponente beschrieben. Zur Verbesserung der Kontakteigenschaften wird dabei neben einem Oxid eines Elements der dritten Nebengruppe des Periodensystems, insbesondere Yttriumoxid, zumindest ein Metalloxid eines Elements der 6. Nebengruppe des Periodensystems beigemengt. Insbesondere Eisenwolframat (FeWO4) verringert dabei die Kontakterwärmung sowie die Verschweißneigung und führt zu einer hohen Lebensdauer des Kontaktwerkstoffes.Likewise, DE-A-44 10 462 describes a silver-based contact material with iron oxide as the main active component. To improve the contact properties, in addition to an oxide of an element of the third subgroup of the periodic table, in particular yttrium oxide, at least one metal oxide of an element of the 6th subgroup of the periodic table is added. Iron tungstate (FeWO 4 ) in particular reduces contact heating and the tendency to weld and leads to a long service life of the contact material.

Desweiteren ist aus der DE-A-41 17 311 ein Kontaktwerkstoff auf Silberbasis bekannt, welcher als Wirkkomponenten Eisenoxid in Massenanteilen zwischen 1 % und 50 % und ein Oxid eines weiteren chemischen Elementes in Massenanteilen zwischen 0,01 % und 5 % enthält. Es ist dabei erkannt worden, daß sich insbesondere das Temperaturverhalten eines Silber-Eisenoxid-Kontaktwerkstoffes durch die Beimengung von Rheniumoxid, Wismutzirkonat, Boroxid, Zirkonoxid, Molybdänoxid oder Wolframoxid günstig beeinflussen läßt.Furthermore, DE-A-41 17 311 is a contact material known on the basis of silver, which as the active components iron oxide in proportions between 1% and 50% and an oxide of one further chemical element in mass fractions between Contains 0.01% and 5%. It has been recognized that especially the temperature behavior of a silver-iron oxide contact material by adding rhenium oxide, bismuth zirconate, Boron oxide, zirconium oxide, molybdenum oxide or tungsten oxide can be influenced favorably.

Als Herstellungsverfahren für einen Kontaktwerkstoff auf Silberbasis mit Eisenoxid als Hauptwirkkomponente ist aus der DE-A-43 28 281, der DE-A-41 17 311 und der DE-A-44 10 462 bekannt, entsprechende Anteile von Silberpulver, Eisenoxidpulver und Pulver weiterer Wirkkomponenten zu vermischen und die entstehende Pulvermischung pulvermetallurgisch zu einem Halbzeug oder zu einem Formstück weiterzuverarbeiten. Für die genannten Pulver werden dabei durchweg handelsübliche Pulver verwendet.As a manufacturing process for a silver-based contact material with iron oxide as the main active component is from the DE-A-43 28 281, DE-A-41 17 311 and DE-A-44 10 462 are known, corresponding proportions of silver powder, iron oxide powder and powder to mix other active components and the resulting powder mixture powder metallurgically to a semi-finished product or to process it into a fitting. For the above Powders are all commercially available powders used.

Für die Herstellung eines Formstücks aus dem Kontaktwerkstoff sind im wesentlichen zwei verschiedene pulvermetallurgische Verfahren bekannt.For the production of a molded part from the contact material are essentially two different powder metallurgical Process known.

Bei der Formteiltechnik wird die Pulvermischung durch Formpressen zu einem Formteil verpreßt, welches durch Sintern und ggf. weiteres Pressen zu einem fertigen Formstück verarbeitet wird. Für die Herstellung eines Formstücks in Form eines Kontaktstücks kann das Formteil zusätzlich mit einer Schicht aus Reinsilber zur sicheren Verbindung des Kontaktstucks mit der Unterlage durch Hartlöten verpreßt werden.In molding technology, the powder mixture is made by compression molding pressed into a molded part, which by sintering and if necessary, further pressing into a finished molding becomes. For the production of a shaped piece in the form of a contact piece the molded part can also be coated with a layer Pure silver for the safe connection of the contact piece with the Pad to be pressed by brazing.

Bei der Strangpreßtechnik wird die Pulvermischung zunächst zu einem porösen Preßling oder Barren gepreßt und/oder gesintert. Der Preßling oder Barren wird, ggf. zusammen mit einer Schicht aus Reinsilber, durch Strangpressen zu einem Strang gepreßt, aus welchem die Formstücke abgetrennt und eventuell einer nachfolgenden Behandlung unterzogen werden.In the extrusion technique, the powder mixture is initially too a porous compact or ingot is pressed and / or sintered. The compact or ingot is, if necessary, together with a Pure silver layer, extruded into one strand pressed, from which the fittings are separated and possibly undergo a subsequent treatment.

Ein Nachteil der durch Mischen von Silberpulver mit handelsüblichen Oxidpulvern hergestellten Silber-Eisenoxid-Kontaktwerkstoffen ist ihre schlechte Verformbarkeit. Derartige Kontaktwerkstoffe eignen sich schlecht für die Herstellung von Nieten, insbesondere von Nieten mit einem großem Kopf/Schaftverhältnis. Da der Nietenkopf in der Regel durch eine Druckverformung aus einem Formstück in Gestalt eines Drahtes herausgebildet wird, muß eine hohe Verformbarkeit des verwendeten Werkstoffs vorausgesetzt werden.A disadvantage of mixing silver powder with commercial ones Oxide powders produced silver-iron oxide contact materials is their poor ductility. Such contact materials are poorly suited for the production of Rivets, especially rivets with a large head / shaft ratio. Since the rivet head is usually by a Compression deformation from a shaped piece in the form of a wire is formed, a high deformability of the used Material are required.

Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren zur Herstellung eines Erzeugnisses aus einem Kontaktwerkstoff mit hervorragenden Schalteigenschaften sowie einer gegenüber dem Stand der Technik deutlich verbesserten Verformbarkeit anzugeben. Weiter ist es Aufgabe der Erfindung, einen derartigen Kontaktwerkstoff sowie ein Erzeugnis, insbesondere in Form einer Niete, aus dem Kontaktwerkstoff anzugeben, welches sich besonders für eine Anwendung in der Energietechnik eignet.The invention has for its object a method for Manufacture of a product from a contact material excellent switching properties and one compared to the State of the art to provide significantly improved deformability. Another object of the invention is such Contact material and a product, in particular in the form a rivet to indicate from the contact material, which is particularly suitable for use in energy technology.

Bezüglich des Verfahrens zur Herstellung eines Erzeugnisses aus einem Kontaktwerkstoff auf Silberbasis mit Eisenoxid als Hauptwirkkomponente wird diese Aufgabe gelöst, indem zunächst eine Pulvermischung aus Silber (Ag) und Eisen (Fe) gebildet wird, in der das Eisen (Fe) in Form eines Pulvers mit einer mittleren Korngröße von größer als 1 µm verwendet wird, und wobei danach diese Pulvermischung pulvermetallurgisch zu dem Formstück weiterverarbeitet und dabei das Eisen (Fe) zu Eisenoxid (Fe2O3/Fe3O4) oxidiert wird.With regard to the method for producing a product from a silver-based contact material with iron oxide as the main active component, this object is achieved by first forming a powder mixture of silver (Ag) and iron (Fe) in which the iron (Fe) is in the form of a powder an average grain size of greater than 1 μm is used, and then this powder mixture is further processed by powder metallurgy to give the shaped piece and the iron (Fe) is oxidized to iron oxide (Fe 2 O 3 / Fe 3 O 4 ).

Bezüglich des Kontaktwerkstoffes wird die Aufgabe erfindungsgemäß gelöst durch einen Kontaktwerkstoff auf Silberbasis mit Eisenoxid als Hauptwirkkomponente, welcher Silber und Eisenoxid (Fe2O3/Fe3O4) umfaßt, wobei die mittlere Korngröße des Oxids größer als 1 µm, vorzugsweise größer als 3 µm, ist.With regard to the contact material, the object is achieved according to the invention by a silver-based contact material with iron oxide as the main active component, which comprises silver and iron oxide (Fe 2 O 3 / Fe 3 O 4 ), the mean grain size of the oxide being greater than 1 μm, preferably greater than 3 µm is.

Die Erfindung geht von der Erkenntnis aus, daß die Verformbarkeit eines Kontaktwerkstoffes auf Silberbasis mit Eisenoxid als Hauptwirkkomponente im wesentlichen durch die mittlere Korngröße der Eisenoxid-Partikel in der Silbermatrix bestimmt ist. Innerhalb eines Intervalls für eine mittlere Korngröße der Eisenoxid-Partikel von 1 µm bis 10 µm weist ein derartiger Kontaktwerkstoff mit einer großen mittleren Korngröße der Eisenoxid-Partikel eine höhere Verformbarkeit auf als ein Kontaktwerkstoff mit einer kleinen mittleren Korngröße. Mit den herkömmlichen Herstellungsverfahren läßt sich jedoch kein Silber-Eisenoxid-Kontaktwerkstoff herstellen, welcher Eisenoxid-Partikel mit einer mittleren Korngröße von mehr als 1 µm aufweist, da Eisenoxid-Pulver im Handel nur mit einer mittleren Korngröße von weniger als 1 µm erhältlich sind.The invention is based on the knowledge that the deformability a silver-based contact material with iron oxide as the main active component essentially through the middle Grain size of the iron oxide particles determined in the silver matrix is. Within an interval for a medium one The grain size of the iron oxide particles is from 1 µm to 10 µm such contact material with a large average grain size the iron oxide particles have a higher deformability as a contact material with a small average grain size. With the conventional manufacturing process but do not produce a silver-iron oxide contact material, which iron oxide particles with an average grain size of has more than 1 µm, since iron oxide powder is only commercially available an average grain size of less than 1 µm available are.

Da jedoch Eisen-Pulver verfügbar sind, deren mittlere Korngrößen größer als 1 µm sind, läßt sich durch die Verwendung von Eisen-Pulver statt Eisenoxid-Pulver und anschließender Oxidation des Eisens zu Eisenoxid ein Kontaktwerkstoff erzielen, bei dem die mittlere Korngröße der Eisenoxid-Partikel in einem Bereich von mehr als 1 µm liegt. Das Eisenoxid kann dabei reines Fe2O3 oder Fe3O4 oder eine Mischung aus diesen Oxiden sein. Da im Vergleich zu herkommlichen Herstellungsverfahren kein zusätzlicher Arbeitsschritt notwendig wird, ist das erfindungsgemäße Verfahren besonders kostengünstig.However, since iron powders are available whose average grain sizes are larger than 1 μm, the use of iron powder instead of iron oxide powder and subsequent oxidation of iron to iron oxide enables a contact material to be obtained in which the average grain size of the iron oxide particles is in a range of more than 1 µm. The iron oxide can be pure Fe 2 O 3 or Fe 3 O 4 or a mixture of these oxides. Since no additional work step is necessary in comparison to conventional manufacturing methods, the method according to the invention is particularly inexpensive.

Unter einem Erzeugnis soll hier der in beliebiger Form vorliegende Kontaktwerkstoff verstanden werden. Eine bloße Pulvermischung oder eine lockere Pressung der Pulvermischung, wobei das Eisen noch nicht zu Eisenoxid oxidiert ist, stellt kein Erzeugnis in diesem Sinne dar. Der genannte Barren, in welchem Eisen zu Eisenoxid oxidiert wurde oder ein fertiges Formstück, sind jedoch solche Erzeugnisse.A product should be the one in any form Contact material can be understood. A mere powder mixture or a loose compression of the powder mixture, the iron has not yet been oxidized to iron oxide is not a product in this sense. The mentioned ingot, in which iron has been oxidized to iron oxide or a finished one Fitting, however, are such products.

Um bei guten Kontakteigenschaften gleichzeitig eine hohe Verformbarkeit zu erhalten, ist es vorteilhaft, daß Eisen in Form eines Pulvers mit einer mittleren Korngröße von größer als 3 µm verwendet wird.In order to ensure high ductility with good contact properties to get it, it is advantageous that iron in Form of a powder with an average grain size of larger than 3 µm is used.

Die Oxidation des Eisens erfolgt vorteilhafterweise in der Pulvermischung, da durch die zunehmende Verdichtung der Pulvermischung in nachfolgenden Arbeitsschritten eine vollständige Oxidation erschwert ist. Die Oxidation ist jedoch auch in einem Rohling des Erzeugnisses möglich, welcher noch eine genügend hohe Porosität bzw. Gasdurchlässigkeit aufweist. Ein solcher Rohling ist beispielsweise der in der Strangpreßtechnik bereitzustellende Barren, der nachfolgend zu einem Strang verpreßt wird. Ebenso kann ein solcher Rohling ein in der Formteiltechnik hergestelltes Vorprodukt für ein Formteil sein.The oxidation of the iron advantageously takes place in the Powder mixture because of the increasing compression of the powder mixture a complete one in subsequent steps Oxidation is difficult. However, the oxidation is too possible in a blank of the product, which is still one has sufficiently high porosity or gas permeability. On such a blank is, for example, that in extrusion technology to be provided ingot, which subsequently becomes a strand is pressed. Such a blank can also be used in the Molding technology manufactured preliminary product for a molding his.

Vorzugsweise wird das Eisen durch eine Wärmebehandlung in einer oxidierenden Atmosphäre, vorzugsweise in Luft oder Sauerstoff oxidiert. Vorteilhafterweise erfolgt dabei die Wärmebehandlung bei einer Temperatur von 500 °C bis 1000 °C, vorzugsweise bei etwa 700 °C.Preferably, the iron is treated in a heat treatment oxidizing atmosphere, preferably in air or oxygen oxidized. The heat treatment is advantageously carried out at a temperature of 500 ° C to 1000 ° C, preferably at about 700 ° C.

Für die Kontakteigenschaften des Kontaktwerkstoffs bzw. des Erzeugnisses aus dem Kontaktwerkstoff ist es von Vorteil, wenn als Oxid eines weiteren Metalls Zirkonoxid (ZrO2) oder Rheniumoxid (ReO2/ReO3/Re2O7) verwendet wird. Dabei kann das Rheniumoxid reines ReO2, ReO3 oder Re2O7 sein, es kann aber auch als Mischung der genannten Oxide vorliegen. Von diesen Metalloxiden ist insbesondere bekannt, daß sie die Übertemperatur, die sich aus der Kontakterwärmung ergibt und im wesentlichen von dem elektrischen Widerstand der Kontaktbrücke abhängt, günstig beeinflussen, d.h. verringern.For the contact properties of the contact material or the product made from the contact material, it is advantageous if zirconium oxide (ZrO 2 ) or rhenium oxide (ReO 2 / ReO 3 / Re 2 O 7 ) is used as the oxide of another metal. The rhenium oxide can be pure ReO 2 , ReO 3 or Re 2 O 7 , but it can also be present as a mixture of the oxides mentioned. These metal oxides are known in particular to favorably influence, ie reduce, the excess temperature which results from the contact heating and essentially depends on the electrical resistance of the contact bridge.

Die Schalteigenschaften des Kontaktwerkstoffs lassen sich gunstig beeinflussen, indem der Pulvermischung weitere Metalle und/oder weitere Metalloxide beigemischt werden. Günstig für die Schalteigenschaften sind beispielsweise Metalle aus der 3. und 6. Nebengruppe des Periodensystems und/oder Oxide dieser Metalle.The switching properties of the contact material can be favorably by adding more metals to the powder mixture and / or further metal oxides are added. Cheap for the switching properties are, for example, metals from the 3rd and 6th subgroup of the periodic table and / or Oxides of these metals.

Günstige Schalteigenschaften besitzt der Kontaktwerkstoff, wenn das Eisenoxid (Fe2O3/Fe3O4) in einem Massenanteil zwischen 1 % und 50 % und ein Oxid des weiteren Metalls in einem Massenanteil zwischen 0,01 % und 5 % vorliegen. The contact material has favorable switching properties if the iron oxide (Fe 2 O 3 / Fe 3 O 4 ) is present in a mass fraction between 1% and 50% and an oxide of the further metal in a mass fraction between 0.01% and 5%.

Die Aufgabe bezüglich des Erzeugnisses wird gelöst durch ein Erzeugnis aus einem Kontaktwerkstoff auf Silberbasis, welcher Silber und als Hauptwirkkomponente Eisenoxid umfaßt, wobei die mittlere Korngröße des Eisenoxids größer als 1 µm, vorzugsweise größer als 3 µm ist. Insbesondere eignet sich der Kontaktwerkstoff besonders für ein Kontaktstück in Form einer Niete für ein Schaltgerät der Energietechnik, z.B. ein Niederspannungsschalter.The object regarding the product is solved by a Product made of a silver-based contact material, which Silver and iron oxide as the main active component, wherein the mean grain size of the iron oxide is greater than 1 μm, preferably is larger than 3 µm. The is particularly suitable Contact material especially for a contact piece in the form of a Rivet for a switching device in energy technology, e.g. a low voltage switch.

Claims (13)

  1. Process for producing a product from a silver-based contact material with iron oxide as the main active component, in which first of all a powder mixture is formed from silver (Ag) and iron (Fe), in which mixture the iron (Fe) is used in the form of a powder with a main grain size of greater than 1 µm, and in which this powder mixture is then processed further by powder metallurgy to form the product, and during this operation the iron (Fe) is oxidized to form iron oxide (Fe2O3/Fe3O4).
  2. Process according to Claim 1, characterized in that iron (Fe) in the form of a powder with a mean grain size of greater than 3 µm is used.
  3. Process according to one of Claims 1 to 2, characterized in that the iron (Fe) is oxidized in the powder mixture or in a product blank.
  4. Process according one of Claims 1 to 3, characterized in that the iron (Fe) is oxidized by a heat treatment in an oxidizing atmosphere, preferably air or oxygen.
  5. Process according to Claim 4, characterized in that the heat treatment takes place at a temperature of from 500°C to 1000°C, preferably at 700°C.
  6. Process according to one of Claims 1 to 5, characterized in that an oxide of at least one further metal and/or at least one further metal is admixed with the powder mixture.
  7. Process according to Claim 6, characterized in that the oxide of the further metal is zirconium oxide (ZrO2) or rhenium oxide (ReO2/ReO3/Re2O7).
  8. Silver-based contact material which comprises silver and, as the main active component, iron oxide (Fe2O3/Fe3O4), the mean grain size of the iron oxide being greater than 1 µm, preferably greater than 3 µm.
  9. Contact material according to Claim 8, characterized in that the iron oxide (Fe2O3/Fe3O4) is present in proportions by mass between 1% and 50%.
  10. Contact material according to Claim 8 or 9, characterized in that it contains an oxide of a further metal, which is present in proportions by mass of between 0.01% and 5%.
  11. Contact material according to Claim 10, characterized in that the oxide of the further metal is zirconium oxide (ZrO2) or rhenium oxide (ReO2/ReO3/Re2O7).
  12. Product made from a silver-based contact material which comprises silver and, as the main active component, iron oxide (Fe2O3/Fe3O4), the mean grain size of the iron oxide being greater than 1 µm, preferably greater than 3 µm.
  13. Product according to Claim 12 which is designed as a contact piece, preferably in the form of a rivet, for power engineering switchgear, in particular for a low-voltage circuit breaker.
EP97935481A 1996-08-01 1997-07-24 Method of producing a product from a silver-based contact material, contact material and product produced therefrom Expired - Lifetime EP0916146B1 (en)

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DE19631141 1996-08-01
DE19631141 1996-08-01
PCT/DE1997/001569 WO1998006119A1 (en) 1996-08-01 1997-07-24 Method of producing a product from a silver-based contact material, contact material and product produced therefrom

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EP0916146B1 true EP0916146B1 (en) 2002-12-04

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EP (1) EP0916146B1 (en)
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DE (1) DE59708897D1 (en)
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CN1820335A (en) * 2004-06-18 2006-08-16 田中贵金属工业株式会社 Relay for sealed AC load and ag-base contact element material for use therein
CN112475295B (en) * 2020-09-30 2022-11-15 浙江福达合金材料科技有限公司 Silver ferric oxide electric contact material with oxide particles dispersed and distributed and preparation method thereof

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Publication number Priority date Publication date Assignee Title
US2394501A (en) * 1942-09-12 1946-02-05 Square D Co Electrical contact
DE1153178B (en) * 1959-08-01 1963-08-22 Duerrwaechter E Dr Doduco Use of a deformable silver-metal oxide material for electrical contacts
CH588152A5 (en) * 1972-12-11 1977-05-31 Siemens Ag
DE4117311A1 (en) * 1991-05-27 1992-12-03 Siemens Ag CONTACT MATERIAL ON A SILVER BASE FOR USE IN SWITCHGEAR DEVICES IN ENERGY TECHNOLOGY
ES2113671T3 (en) * 1993-08-23 1998-05-01 Siemens Ag SILVER BASED CONTACT MATERIAL, USE OF SUCH CONTACT MATERIAL IN A SWITCHING DEVICE FOR ENERGY TECHNIQUE, AND PROCEDURE FOR OBTAINING CONTACT MATERIAL.
DE4328281A1 (en) * 1993-08-23 1995-03-02 Siemens Ag Contact material based on silver for use in switching instruments in energy technology
DE4343550A1 (en) * 1993-12-20 1995-06-22 Siemens Ag Contact material based on silver for use in switching devices of power engineering
DE19543208C1 (en) * 1995-11-20 1997-02-20 Degussa Silver@-iron@ material contg. oxide additives

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WO1998006119A1 (en) 1998-02-12
EP0916146A1 (en) 1999-05-19
BR9710794A (en) 1999-08-17
DE59708897D1 (en) 2003-01-16
ES2187801T3 (en) 2003-06-16
US6056916A (en) 2000-05-02

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