EP0795367A1 - Silver-iron material for electrical switch contacts and process for its preparation - Google Patents

Silver-iron material for electrical switch contacts and process for its preparation Download PDF

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Publication number
EP0795367A1
EP0795367A1 EP97101342A EP97101342A EP0795367A1 EP 0795367 A1 EP0795367 A1 EP 0795367A1 EP 97101342 A EP97101342 A EP 97101342A EP 97101342 A EP97101342 A EP 97101342A EP 0795367 A1 EP0795367 A1 EP 0795367A1
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EP
European Patent Office
Prior art keywords
iron
silver
weight
materials
microhardness
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EP97101342A
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German (de)
French (fr)
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EP0795367B1 (en
Inventor
Wolfgang Dr. Weise
Willi Malikowski
Roger Wolmer
Peter Dr. Braumann
Andreas Koffler
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Umicore AG and Co KG
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Degussa GmbH
Degussa Huels AG
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    • 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
    • C22C1/0466—Alloys based on noble metals
    • 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
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/09—Mixtures of metallic powders
    • 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
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/12—Metallic powder containing non-metallic particles
    • 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
    • C22C32/0084—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 carbon or graphite as the main non-metallic constituent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C5/00—Alloys based on noble metals
    • C22C5/06—Alloys based on silver
    • 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
    • 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
    • H01H1/027—Composite material containing carbon particles or fibres
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
    • H01H11/04—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts
    • H01H11/048—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts by powder-metallurgical processes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/922—Static electricity metal bleed-off metallic stock
    • Y10S428/9265—Special properties
    • Y10S428/929—Electrical contact feature
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12014—All metal or with adjacent metals having metal particles
    • Y10T428/1216—Continuous interengaged phases of plural metals, or oriented fiber containing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12014—All metal or with adjacent metals having metal particles
    • Y10T428/1216—Continuous interengaged phases of plural metals, or oriented fiber containing
    • Y10T428/12167—Nonmetal containing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12771—Transition metal-base component
    • Y10T428/12861—Group VIII or IB metal-base component
    • Y10T428/12896—Ag-base component
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/28—Web or sheet containing structurally defined element or component and having an adhesive outermost layer
    • Y10T428/2813—Heat or solvent activated or sealable

Definitions

  • the invention relates to a sintered silver-iron material with 0.5 to 20% by weight of iron and 0 to 5% by weight of other metallic, oxidic, nitridic and / or carbidic additives, the rest silver, for electrical contacts and a method for the production of this material.
  • DE-AS 11-53-178 discloses silver contact materials which, in addition to silver and the component to be oxidized, range from 0.001 to 1%. Nickel, iron, molybdenum, cobalt, chromium, titanium and / or Contain vanadium.
  • DE-AS 11 06 965 describes a process for producing densely sintered shaped bodies made of silver with 5 to 50% of at least one of the metals vanadium, tantalum, chromium, molybdenum, tungsten, iron, cobalt or nickel, which can also serve as contact material.
  • silver-iron materials have so far not been used more widely because they tend to form cover layers when switching and thus lead to high contact heating. None of these materials achieve the favorable properties of the silver-nickel sintered materials.
  • the iron particles in the sintered material have a carbon content of more than 0.25% by weight and a microhardness of more than 200 HV 0.025.
  • the iron particles should preferably have a carbon content of more than 0.4% by weight and a microhardness of more than 400 HV 0.025.
  • Silver-iron materials in which the iron particles in the sintered state have a carbon content of 0.6 to 1.2% by weight and a microhardness of more than 600 HV 0.025, have proven best.
  • These materials are manufactured by mixing silver powder with 0.5 to 20% by weight iron powder and 0 to 5% by weight other metallic, oxidic, nitridic and / or carbidic additives, cold isostatic pressing, sintering at 650 to 940 ° C under protective gas and extrusion, using an iron powder which contains more than 0.25% by weight of carbon, and the sintering must take place in a hydrogen-free protective gas atmosphere.
  • the silver-iron material according to the invention shows practically the same behavior as silver-nickel materials with regard to the service life and the other properties.
  • the silver-iron materials can contain 0 to 5% by weight of metallic additives such as zinc, copper, manganese, rhenium, iridium and ruthenium, or non-metallic additives such as tungsten oxide, molybdenum oxide, iron oxides, magnesium oxide, calcium oxide, yttrium oxide, tantalum oxide, chromium oxide, manganese oxide, Zinc oxide, aluminum oxide, indium oxide, silicon oxide and zirconium oxide can be added.
  • metallic additives such as zinc, copper, manganese, rhenium, iridium and ruthenium
  • non-metallic additives such as tungsten oxide, molybdenum oxide, iron oxides, magnesium oxide, calcium oxide, yttrium oxide, tantalum oxide, chromium oxide, manganese oxide, Zinc oxide, aluminum oxide, indium oxide, silicon oxide and zirconium oxide can be added.
  • the materials according to the invention can also be processed better.
  • the reason for this is that the iron is distributed significantly more finely within the silver matrix during extrusion and that the iron does not deform into elongated iron lines due to the brittleness, as in the known silver-iron materials.
  • the materials can be manufactured economically and are comparable in their switching properties to the silver-nickel material, in particular the overtemperature and service life show values that silver-nickel materials also achieve.
  • AgNi20 90 110,000 2nd AgFe8.5Zn1.5 116 95,000 3rd AgFe8 130 95,000 4th AgFe8Re5 95 90,000 5 AgFe6MgO0.5 95 90,000 6 AgFe8.5Zn1.5 110 110,000 7 AgFe6 110 110,000 8th AgFe6Re0.5 80 100,000 9 AgFe4MgO0.5 80 105,000 10th AgFe4 80 100,000 11 AgFe10 120 125,000 12th AgFe8Al2O30.5 95 110,000 13 AgFe8SnO20.5 90 110,000 14 AgFe8SiO20.5 90 115,000 15 AgFe8Ir0.5 95 125,000 16 AgFe8Ru0.5 90 115,000
  • the wires can always be easily processed into contact pieces.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Composite Materials (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Powder Metallurgy (AREA)
  • Contacts (AREA)

Abstract

Gesinterte Silber-Eisenwerkstoffe für elektrisch Kontakte, die in ihren Eigenschaften mit Silber-Nickel-Werkstoffen vergleichbar sind, erhält man, wenn man Eisenpulver mit mehr als 0,25 Gew.% Kohlenstoff und Mikrohärten von mehr als 200 HV 0,025 einsetzt und das Sintern in einer wasserstofffreien Schutzgasatmosphäre durchführt.Sintered silver-iron materials for electrical contacts, whose properties are comparable to silver-nickel materials, can be obtained by using iron powder with more than 0.25% by weight carbon and microhardness of more than 200 HV 0.025 and sintering in in a hydrogen-free protective gas atmosphere.

Description

Die Erfindung betrifft einen gesinterten Silber-Eisen-Werkstoff mit 0,5 bis 20 Gew.% Eisen und 0 bis 5 Gew.% sonstiger metallischer, oxidischer, nitridischer und/oder carbidischer Zusätze, Rest Silber, für elektrische Kontakte und ein Verfahren zur Herstellung dieses Werkstoffs.The invention relates to a sintered silver-iron material with 0.5 to 20% by weight of iron and 0 to 5% by weight of other metallic, oxidic, nitridic and / or carbidic additives, the rest silver, for electrical contacts and a method for the production of this material.

Kontaktwerkstoffe für den Einsatz in der elektrischen Energietechnik müssen eine hohe Abbrandfestigkeit, geringe Verschweißkraft und niedrigen Kontaktwiderstand aufweisen. Für luftoffene Schaltgeräte in der Niederspannungstechnik hat sich für Schaltströme von kleiner als 100A der Verbundwerkstoff Silber-Nickel bewährt. Er besitzt eine hohe Abbrandfestigkeit bei sehr gutem Übertemperaturverhalten. Ein Nachteil des Werkstoffes liegt jedoch darin, daß Nickel, insbesondere in Form von Stäuben, schädliche Auswirkungen auf den menschlichen Organismus haben kann. Als Alternative zu Nickel ist daher verschiedentlich Eisen vorgeschlagen worden.Contact materials for use in electrical power engineering must have high erosion resistance, low welding force and low contact resistance. For air-tight switchgear in low-voltage technology, the composite material silver-nickel has proven itself for switching currents of less than 100A. It has a high erosion resistance with very good excess temperature behavior. A disadvantage of the material, however, is that nickel, especially in the form of dusts, can have harmful effects on the human organism. Iron has therefore been proposed variously as an alternative to nickel.

Aus der japanischen Patentanmeldung 79/148109 sind elektrische Kontaktwerkstoffe bekannt, die neben Silber noch Eisen, Nickel, Chrom und/oder Kobalt enthalten. Besonders Werkstoffe der Zusammensetzung AgFe10 zeigen einen hohen Verschleißwiderstand bei noch guter elektrischer Leitfähigkeit.From the Japanese patent application 79/148109 electrical contact materials are known which contain iron, nickel, chromium and / or cobalt in addition to silver. In particular, materials with the composition AgFe10 show a high wear resistance with good electrical conductivity.

Auch in der Zeitschrift

Figure imgb0001
Material & Methods Bd 44, No. 3, Sept. 56, Seite 121-126" werden Silber-Eisen-Werkstoffe für spezielle Kontaktanwendungen beschrieben. Aus der DE-AS 11-53-178 sind Silber-Kontaktwerkstoffe bekannt, die neben Silber und dem zu oxidierenden Bestandteil 0,001 bis 1 % Nickel, Eisen, Molybdän, Kobalt, Chrom, Titan und/oder Vanadium enthalten. Die DE-AS 11 06 965 beschreibt ein Verfahren zur Herstellung dichtgesinterter Formkörper aus Silber mit 5 bis 50 % mindestens eines der Metalle Vanadium, Tantal, Chrom, Molybdän, Wolfram, Eisen, Kobalt oder Nickel, die auch als Kontaktmaterial dienen können.Even in the magazine
Figure imgb0001
Material & Methods Vol 44, No. 3, Sept. 56, page 121-126 "describes silver-iron materials for special contact applications. DE-AS 11-53-178 discloses silver contact materials which, in addition to silver and the component to be oxidized, range from 0.001 to 1%. Nickel, iron, molybdenum, cobalt, chromium, titanium and / or Contain vanadium. DE-AS 11 06 965 describes a process for producing densely sintered shaped bodies made of silver with 5 to 50% of at least one of the metals vanadium, tantalum, chromium, molybdenum, tungsten, iron, cobalt or nickel, which can also serve as contact material.

Silber-Eisen-Werkstoffe fanden bisher jedoch keine breitere Anwendung, da sie beim Schalten zur Bildung von Deckschichten neigen und damit zu hohen Kontakterwärmungen führen. Keiner dieser Werkstoffe erreicht die günstigen Eigenschaften der Silber-Nickel-Sinterwerkstoffe.However, silver-iron materials have so far not been used more widely because they tend to form cover layers when switching and thus lead to high contact heating. None of these materials achieve the favorable properties of the silver-nickel sintered materials.

Bei allen bekannten Silber-Eisen-Werkstoff für elektrische Kontakte werden handelsübliche Eisenpulver eingesetzt, die Kohlenstoffgehalte von weniger als 0,05 Gew.% aufweisen und daher relativ weich sind. Gesintert wird üblicherweise in wasserstoffhaltigen Atmosphären, insbesondere in Stickstoff-Wasserstoffgemischen.In all known silver-iron materials for electrical contacts, commercially available iron powders are used which have carbon contents of less than 0.05% by weight and are therefore relatively soft. Sintering is usually carried out in atmospheres containing hydrogen, in particular in nitrogen-hydrogen mixtures.

Es war daher Aufgabe der vorliegenden Erfindung, einen gesinterten Silber-Eisen-Werkstoff mit 0,5 bis 20 Gew.% Eisen und 0 bis 5 Gew.% sonstiger metallischer, oxidischer, nitridischer und/oder carbidischer Zusätze, Rest Silber, für elektrische Kontakte zu entwickeln, der eine geringe Verschweißneigung, einen geringen Kontaktwiderstand und eine hohe Abbrandfestigkeit und damit hohe Lebensdauer aufweist, und mit diesen Eigenschaften den bekannten Silber-Nickel-Kontaktwerkstoffen möglichst nahe kommt. Außerdem sollte ein Verfahren zur Herstellung solcher Werkstoffe entwickelt werden.It was therefore an object of the present invention to provide a sintered silver-iron material with 0.5 to 20% by weight of iron and 0 to 5% by weight of other metallic, oxidic, nitridic and / or carbidic additives, the rest being silver, for electrical contacts to develop, which has a low tendency to weld, a low contact resistance and a high erosion resistance and thus a long service life, and with these properties comes as close as possible to the known silver-nickel contact materials. A method for manufacturing such materials should also be developed.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß die Eisenteilchen im gesinterten Werkstoff einen Kohlenstoffgehalt von mehr als 0,25 Gew.% und eine Mikrohärte von mehr als 200 HV 0,025 aufweisen.This object is achieved in that the iron particles in the sintered material have a carbon content of more than 0.25% by weight and a microhardness of more than 200 HV 0.025.

Vorzugsweise sollen die Eisenteilchen einen Kohlenstoffgehalt von mehr als 0,4 Gew.% und eine Mikrohärte von mehr als 400 HV 0,025 besitzen.The iron particles should preferably have a carbon content of more than 0.4% by weight and a microhardness of more than 400 HV 0.025.

Am besten bewährt haben sich Silber-Eisen-Werkstoffe, bei denen die Eisenteilchen im gesinterten Zustand einen Kohlenstoffgehalt von 0,6 bis 1,2 Gew.% und eine Mikrohärte von mehr als 600 HV 0,025 aufweisen.Silver-iron materials, in which the iron particles in the sintered state have a carbon content of 0.6 to 1.2% by weight and a microhardness of more than 600 HV 0.025, have proven best.

Die Herstellung dieser Werkstoffe erfolgt durch Mischen von Silberpulver mit 0,5 bis 20 Gew.% Eisenpulver und 0 bis 5 Gew.% sonstiger metallischer, oxidischer, nitridischer und/oder carbidischer Zusätze, kaltisostatischem Pressen, Sintern bei 650 bis 940°C unter Schutzgas und Strangpressen, wobei ein Eisenpulver eingesetzt wird, das mehr als 0,25 Gew.% Kohlenstoff enthält, und das Sintern in einer wasserstofffreien Schutzgasatmosphäre erfolgen muß.These materials are manufactured by mixing silver powder with 0.5 to 20% by weight iron powder and 0 to 5% by weight other metallic, oxidic, nitridic and / or carbidic additives, cold isostatic pressing, sintering at 650 to 940 ° C under protective gas and extrusion, using an iron powder which contains more than 0.25% by weight of carbon, and the sintering must take place in a hydrogen-free protective gas atmosphere.

Überraschenderweise hat es sich gezeigt, daß man beim Einsatz eines Eisenpulvers, das im Ausgangszustand und auch nach dem Sintern mehr als 0,25 Gew.% Kohlenstoff, vorzugsweise zwischen 0,6 bis 1,2 Gew.% Kohlenstoff enthält, und dadurch eine Mikrohärte von mehr als 200 HV 0,025, vorzugsweise mehr als 600 HV 0,025 aufweist, ein Werkstoff erhalten wird, der im praktischen Einsatz eine deutliche Verbesserung im Übertemperaturverhalten bringt. Um den Kohlenstoffgehalt von mehr als 0,25 Gew.% und damit die gewünschte Mikrohärte im gesinterten Zustand beizubehalten, muß das Sintern des Werkstoffs in einer wasserstofffreien Schutzgasatmosphäre erfolgen. Dadurch wird gewährleistet, daß der Kohlenstoffgehalt des Eisenpulvers während des Sinterns nicht verringert wird.Surprisingly, it has been found that when using an iron powder which contains more than 0.25% by weight of carbon, preferably between 0.6 to 1.2% by weight of carbon, both in the initial state and also after sintering, and thereby a microhardness of more than 200 HV 0.025, preferably more than 600 HV 0.025, a material is obtained which brings a significant improvement in the overtemperature behavior in practical use. In order to maintain the carbon content of more than 0.25% by weight and thus the desired microhardness in the sintered state, the material must be sintered in a hydrogen-free protective gas atmosphere. This ensures that the carbon content of the iron powder is not reduced during sintering.

Der erfindungsgemäße Silber-Eisen-Werkstoff zeigt hinsichtlich der Lebensdauer und der sonstigen Eigenschaften praktisch das gleiche Verhalten wie Silber-Nickel-Werkstoffe.The silver-iron material according to the invention shows practically the same behavior as silver-nickel materials with regard to the service life and the other properties.

Den Silber-Eisenwerkstoffen können 0 bis 5 Gew.% metallische Zusätze, wie Zink, Kupfer, Mangan, Rhenium, Iridium und Ruthenium, oder nichtmetallische Zusätze, wie Wolframoxid, Molybdänoxid, Eisenoxide, Magnesiumoxid, Calziumoxid, Yttriumoxid, Tantaloxid, Chromoxid, Manganoxid, Zinkoxid, Aluminiumoxid, Indiumoxid, Siliziumoxid und Zirkonoxid zugesetzt werden.The silver-iron materials can contain 0 to 5% by weight of metallic additives such as zinc, copper, manganese, rhenium, iridium and ruthenium, or non-metallic additives such as tungsten oxide, molybdenum oxide, iron oxides, magnesium oxide, calcium oxide, yttrium oxide, tantalum oxide, chromium oxide, manganese oxide, Zinc oxide, aluminum oxide, indium oxide, silicon oxide and zirconium oxide can be added.

Überraschenderweise lassen sich die erfindungsgemäßen Werkstoffe auch besser verarbeiten. Die Ursache liegt darin, daß das Eisen während des Strangpressens innerhalb der Silbermatrix deutlich feiner verteilt wird und daß sich das Eisen aufgrund der Sprödigkeit nicht zu langgestreckten Eisenzeilen verformt, wie in den bekannten Silber-Eisen-Werkstoffen. Die Werkstoffe lassen sich wirtschaftlich herstellen und sind in allen Schalteigenschaften mit dem Silber-Nickel-Werkstoff vergleichbar, insbesondere die Übertemperatur und Lebensdauer zeigen Werte, die auch Silber-Nickel-Werkstoffe erzielen.Surprisingly, the materials according to the invention can also be processed better. The reason for this is that the iron is distributed significantly more finely within the silver matrix during extrusion and that the iron does not deform into elongated iron lines due to the brittleness, as in the known silver-iron materials. The materials can be manufactured economically and are comparable in their switching properties to the silver-nickel material, in particular the overtemperature and service life show values that silver-nickel materials also achieve.

Dies wurde durch elektrische Schaltversuche in serienmäßigen Schützen nachgewiesen. Die Versuche wurden mit 5,5 KW unter den Schaltbedingungen AC4 nach DIN VDE 0660 durchgeführt. Die Übertemperaturmessung erfolgte an den Kontaktbrücken bei einer Strombelastung von 20 A nach jeweils 20.000 Schaltungen. Die Werkstoffe und die Ergebnisse der mit diesen Werkstoffen durchgeführten Schaltversuche nach einer Gesamtschaltbelastung von 60.000 Schaltspielen sind in folgender Tabelle enthalten und zeigen die Verbesserung der erfindungsgemäßen Werkstoffe 6 bis 16 hinsichtlich der Kontakterwärmung gegenüber den bekannten Werkstoffen AgNi20 und AgFe9,5Zn1,5(Werkstoff 1 und 2) und Werkstoffen mit konventionellen Eisenpulvern (3 bis 5), die weniger als 0,1 Gew.% Kohlenstoff enthalten. Nr. Werkstoff Mittlere Übertemperatur in K Lebensdauer 1 AgNi20 90 110.000 2 AgFe8,5Zn1,5 116 95.000 3 AgFe8 130 95.000 4 AgFe8Re5 95 90.000 5 AgFe6MgO0,5 95 90.000 6 AgFe8,5Zn1,5 110 110.000 7 AgFe6 110 110.000 8 AgFe6Re0,5 80 100.000 9 AgFe4MgO0,5 80 105.000 10 AgFe4 80 100.000 11 AgFe10 120 125.000 12 AgFe8Al2O30,5 95 110.000 13 AgFe8SnO20,5 90 110.000 14 AgFe8SiO20,5 90 115.000 15 AgFe8Ir0,5 95 125.000 16 AgFe8Ru0,5 90 115.000 This has been proven by electrical switching tests in standard contactors. The tests were carried out with 5.5 KW under the switching conditions AC4 according to DIN VDE 0660. The overtemperature measurement was carried out on the contact bridges with a current load of 20 A after every 20,000 switching operations. The materials and the results of the switching tests carried out with these materials after a total switching load of 60,000 switching cycles are contained in the following table and show the improvement of materials 6 to 16 according to the invention in terms of contact heating compared to the known materials AgNi20 and AgFe9.5Zn1.5 (material 1 and 2) and materials with conventional iron powders (3 to 5) that contain less than 0.1% by weight of carbon. No. material Average overtemperature in K lifespan 1 AgNi20 90 110,000 2nd AgFe8.5Zn1.5 116 95,000 3rd AgFe8 130 95,000 4th AgFe8Re5 95 90,000 5 AgFe6MgO0.5 95 90,000 6 AgFe8.5Zn1.5 110 110,000 7 AgFe6 110 110,000 8th AgFe6Re0.5 80 100,000 9 AgFe4MgO0.5 80 105,000 10th AgFe4 80 100,000 11 AgFe10 120 125,000 12th AgFe8Al2O30.5 95 110,000 13 AgFe8SnO20.5 90 110,000 14 AgFe8SiO20.5 90 115,000 15 AgFe8Ir0.5 95 125,000 16 AgFe8Ru0.5 90 115,000

Die Herstellung der erfindungsgemäßen Werkstoffe ist in den nachstehenden Beispielen dargestellt. Dabei wird stets ein Eisenpulver eingesetzt, das etwa 0,9 Gew.% Kohlenstoff enthält und eine Härte von etwa 800 HV 0,025 aufweist.

  • 1. 80 g Eisenpulver wird mit 920 g Silberpulver gemischt. Die Mischung wird kaltisostatisch gepreßt zu einem Strangpreßbolzen. Dieser wird unter wasserstofffreiem Stickstoff bei 850°C gesintert und zu Draht mit einem Durchmesser von 8 mm stranggepreßt. Der Draht wird durch Ziehen auf die gewünschten Enddurchmesser weiter verformt.
  • 2. 80 g Eisenpulver und 5 g Rheniumpulver werden mit 915 g Silberpulver gemischt. Die Mischung wird kaltisostatisch gepreßt zu einem Strangpreßbolzen. Dieser wird unter wasserstofffreiem Stickstoff bei 850°C gesintert und zu Draht mit einem Durchmesser von 8 mm stranggepreßt. Der Draht wird durch Ziehen auf die gewünschten Enddurchmesser weiter verformt.
The preparation of the materials according to the invention is shown in the examples below. An iron powder is always used which contains about 0.9% by weight of carbon and has a hardness of about 800 HV 0.025.
  • 1. 80 g of iron powder is mixed with 920 g of silver powder. The mixture is cold isostatically pressed into an extrusion billet. This is sintered under hydrogen-free nitrogen at 850 ° C and extruded into wire with a diameter of 8 mm. The wire is further deformed by pulling to the desired final diameter.
  • 2. 80 g of iron powder and 5 g of rhenium powder are mixed with 915 g of silver powder. The mixture is cold isostatically pressed into an extrusion billet. This is sintered under hydrogen-free nitrogen at 850 ° C and extruded into wire with a diameter of 8 mm. The wire is further deformed by pulling to the desired final diameter.

Die Drähte lassen sich stets gut zu Kontaktstücken weiterverarbeiten.The wires can always be easily processed into contact pieces.

Claims (4)

Gesinterter Silber-Eisenwerkstoff mit 0,5 bis 20 Gew.% Eisen und 0 bis 5 Gew.% sonstiger metallischer, oxidischer, nitridischer und/oder carbidischer Zusätze, Rest Silber, für elektrische Kontakte,
dadurch gekennzeichnet,
daß die Eisenteilchen im gesinterten Werkstoff einen Kohlenstoffgehalt von mehr als 0,25 Gew.% und eine Mikrohärte von mehr als 200 HV 0,025 aufweisen.Sintered silver-iron material with 0.5 to 20% by weight of iron and 0 to 5% by weight of other metallic, oxidic, nitridic and / or carbidic additives, the rest silver, for electrical contacts,
characterized by
that the iron particles in the sintered material have a carbon content of more than 0.25% by weight and a microhardness of more than 200 HV 0.025. Silber-Eisenwerkstoff nach Anspruch 1,
dadurch gekennzeichnet,
daß die Eisenteilchen im Werkstoff einen Kohlenstoffgehalt von mehr als 0,4 Gew.% und eine Mikrohärte von mehr als 400 HV 0,025 besitzen.Silver-iron material according to claim 1,
characterized by
that the iron particles in the material have a carbon content of more than 0.4% by weight and a microhardness of more than 400 HV 0.025. Silber-Eisenwerkstoff nach Anspruch 1 und 2,
dadurch gekennzeichnet,
daß die Eisenteilchen im Werkstoff einen Kohlenstoffgehalt von 0,6 bis 1,2 Gew.% und eine Mikrohärte von mehr als 600 HV 0,025 aufweisen.Silver-iron material according to claim 1 and 2,
characterized by
that the iron particles in the material have a carbon content of 0.6 to 1.2% by weight and a microhardness of more than 600 HV 0.025. Verfahren zur Herstellung von Silber-Eisenwerkstoffen nach Anspruch 1 bis 3, durch Mischen von Silberpulver mit 0,5 bis 20 Gew.% Eisenpulver und 0 bis 5 Gew.% sonstiger metallischer, oxidischer, nitridischer und/oder carbidischer Zusätze, kaltisostatischem Pressen, Sintern bei 650 bis 940°C und Strangpressen,
dadurch gekennzeichnet,
daß das Eisenpulver mehr als 0,25 Gew.% Kohlenstoff enthält und das Sintern in einer wasserstofffreien Schutzgasatmosphäre vorgenommen wird.Process for the production of silver-iron materials according to Claims 1 to 3, by mixing silver powder with 0.5 to 20% by weight of iron powder and 0 to 5% by weight of other metallic, oxidic, nitridic and / or carbidic additives, cold isostatic pressing, sintering at 650 to 940 ° C and extrusion,
characterized by
that the iron powder contains more than 0.25% by weight of carbon and that the sintering is carried out in a hydrogen-free protective gas atmosphere.
EP97101342A 1996-02-27 1997-01-29 Silver-iron material for electrical switch contacts and process for its preparation Expired - Lifetime EP0795367B1 (en)

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DE19607183A DE19607183C1 (en) 1996-02-27 1996-02-27 Sintered silver@-iron@ alloy for making electrical contacts
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US9018552B2 (en) * 2011-11-04 2015-04-28 Taiwan Electric Contacts Corp. Electrical contact including stainless steel material
EP2644723B1 (en) * 2012-03-26 2017-01-18 Umicore AG & Co. KG Composite material
CN103014402B (en) * 2012-12-21 2017-05-31 重庆川仪自动化股份有限公司 Alloy as electric contact material and its laminar composite are slided in high-melting point alloy element enhancing
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CN107675017B (en) * 2017-08-04 2020-03-31 福达合金材料股份有限公司 Silver iron nickel electrical contact material and preparation method thereof
CN108054031B (en) * 2017-09-11 2019-10-25 大连大学 A kind of sheet iron reticulates the Ag-based electrical contact material of distribution reinforcing
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CN1080766C (en) 2002-03-13
US5985440A (en) 1999-11-16
JPH09235634A (en) 1997-09-09
EP0795367B1 (en) 2001-06-20
ES2160270T3 (en) 2001-11-01
CN1161380A (en) 1997-10-08
DE59703840D1 (en) 2001-07-26

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