EP0024349B1 - Material for electric contacts and process for its manufacture - Google Patents

Material for electric contacts and process for its manufacture Download PDF

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Publication number
EP0024349B1
EP0024349B1 EP80104820A EP80104820A EP0024349B1 EP 0024349 B1 EP0024349 B1 EP 0024349B1 EP 80104820 A EP80104820 A EP 80104820A EP 80104820 A EP80104820 A EP 80104820A EP 0024349 B1 EP0024349 B1 EP 0024349B1
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EP
European Patent Office
Prior art keywords
oxide
silver
tin oxide
weight
cdo
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP80104820A
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German (de)
French (fr)
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EP0024349A1 (en
Inventor
Wolfgang Dr. Böhm
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Evonik Operations GmbH
Original Assignee
Degussa GmbH
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Publication date
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Application filed by Degussa GmbH filed Critical Degussa GmbH
Priority to AT80104820T priority Critical patent/ATE2032T1/en
Publication of EP0024349A1 publication Critical patent/EP0024349A1/en
Application granted granted Critical
Publication of EP0024349B1 publication Critical patent/EP0024349B1/en
Expired legal-status Critical Current

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Classifications

    • 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
    • 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
    • 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
    • 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
    • B22F2998/10—Processes characterised by the sequence of their steps

Definitions

  • the invention relates to a material for electrical contacts made of silver, tin oxide and a further metal oxide and a method for its production.
  • DE-B-11 90 677 describes materials for electrical contacts which, in addition to silver, must also contain 0.8 to 6% silver halide and 1 to 4.5% oxide from the group of copper, chromium, tin, cadmium, Iron, ruthenium, nickel, manganese, molybdenum, cobalt, tungsten, uranium, rhodium and palladium can contain.
  • halide-containing contact materials have not proven themselves in practice.
  • the object of the invention was to provide a material for electrical contacts made of silver, tin oxide and a further metal oxide and a method for its production which has a long service life, a low tendency to weld and shows no elevated temperatures when switching.
  • the material contains 8-20 wt .-% tin oxide, 0.05-5 wt .-% tungsten oxide, the rest of silver.
  • This material surprisingly results in a large reduction in the excess temperature, so that the same, in some cases even lower, temperatures are found in the switching device than in Ag / CdO.
  • the welding forces of Ag / Sn0 2 can also be significantly reduced by the addition of tungsten oxide.
  • a material which consists of 10-15% by weight of tin oxide, 0.2-1.5% by weight of tungsten oxide and the rest of silver has proven particularly useful. Surprisingly, even very low tungsten oxide contents result in significant improvements in terms of overtemperature and welding force. Particularly good results are obtained if the Sn0 2 is introduced evenly without agglomerates, with a primary grain size of ⁇ 5 ⁇ m.
  • This fine distribution of the metal oxide components can be achieved by sieving the Sn0 2 before mixing, or particularly advantageously by mixing and kneading the silver, tin oxide and tungsten oxide powders in a moist state.
  • the wet sieving removes secondary agglomerates of Sn0 2 before mixing.
  • secondary agglomerates are destroyed by the high shear forces that occur, and this results in an even and fine-grained distribution of the component.
  • the following table illustrates the essential improvements in switching behavior that were achieved with the material according to the invention compared to Ag / CdO and Ag / Sn0 2 using examples.
  • a 3 TB 54 switching device from Siemens was used for this.
  • the materials according to the invention were produced by powder metallurgy after wet kneading with the following extrusion.

Landscapes

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

Description

Die Erfindung betrifft einen Werkstoff für elektrische Kontakte aus Silber, Zinnoxid und einem weiteren Metalloxid und Verfahren zu seiner Herstellung.The invention relates to a material for electrical contacts made of silver, tin oxide and a further metal oxide and a method for its production.

Für die Herstellung von elektrischen Kontaktstücken hat sich für eine Vielzahl von Anwendungsfällen Ag/CdO bisher am besten bewährt. Aufgrund der Umweltbelastung durch CdO wird jedoch verstärkt versucht, CdO durch ein anderes Metalloxid zu ersetzen. Bei diesen Untersuchungen zeigte es sich, Daß Sn02 ein geeigneter Ersatz für CdO ist. Aufgrund der höheren thermischen Stabilität von Sn02 gegenüber CdO ergibt sich zudem eine deutlich verminderte Abbrandrate, die zur längeren Lebensdauer im Schaltgerät führt. Ein sehr wesentlicher Nachteil von Ag/Sn02 besteht jedoch darin, daß der Übergangswiderstand am Kontakt nach einigen tausend Schaltungen durch Deckschichtbildung zu hoch wird. Dies führt dann in der Regel zu erhöhten Temperaturen im Schaltgerät, die zur Zerstörung des Gerätes führen können und somit unzulässig sind.So far, Ag / CdO has proven to be the best for a large number of applications in the manufacture of electrical contact pieces. However, due to the environmental impact of CdO, attempts are being made to replace CdO with another metal oxide. These investigations showed that Sn0 2 is a suitable replacement for CdO. Due to the higher thermal stability of Sn0 2 compared to CdO, there is also a significantly reduced burn rate, which leads to a longer service life in the switchgear. A very important disadvantage of Ag / Sn0 2 , however, is that the contact resistance at the contact becomes too high after a few thousand switching operations due to the formation of a covering layer. This then generally leads to increased temperatures in the switching device, which can lead to the destruction of the device and are therefore inadmissible.

Ein weiterer Nachteil dieser Ag/Sn02-Werkstoffe gegenüber Ag/CdO besteht in der geringeren Sicherheit gegen Verschweissen. Die Kräfte, die zum Zerreissen der Schweissbrücke erforderlich sind, sind teilweise doppelt so hoch wie die bei Ag/CdO-Kontakten. Damit besteht die Gefahr von Schaltstörungen bei Einsatz von Ag/Sn02,Another disadvantage of these Ag / Sn0 2 materials compared to Ag / CdO is the lower security against welding. The forces required to tear the welding bridge are sometimes twice as high as those with Ag / CdO contacts. There is therefore a risk of switching faults when using Ag / Sn0 2 ,

Es ist daher versucht worden, durch den Zusatz weiterer Metalloxide zu Ag/Sn02 die Verschweißsicherheit zu erhöhen, wobei beispielsweise Wismutoxid (DE-A1-2754335) oder Indiumoxid (DE-A1-24 28147) verwendet werden. Diese Zusätze verbessern zwar die Verschweißsicherheit, bedingen jedoch eine erhöhte Temperatur am Kontakt und am Schaltgerät, was die Lebensdauer der Geräte beeinträchtigt.Attempts have therefore been made to increase the welding security by adding further metal oxides to Ag / Sn0 2 , bismuth oxide (DE-A1-2754335) or indium oxide (DE-A1-24 28147) being used, for example. Although these additives improve welding security, they require an increased temperature on the contact and on the switching device, which affects the service life of the devices.

In der DE-B-11 90 677 werden Werkstoffe für elektrische Kontakte beschrieben, die neben Silber noch zwingend 0,8 bis 6 % Silberhalogenid enthalten müssen und 1 bis 4,5 % Oxid aus der Gruppe des Kupfers, Chroms, Zinns, Cadmiums, Eisens, Rutheniums, Nickels, Mangans, Molybdäns, Kobalts, Wolframs, Urans, Rhodiums und Palladiums enthalten können. Solche halogenidhaltigen Kontaktwerkstoffe haben sich in der Praxis nicht bewährt.DE-B-11 90 677 describes materials for electrical contacts which, in addition to silver, must also contain 0.8 to 6% silver halide and 1 to 4.5% oxide from the group of copper, chromium, tin, cadmium, Iron, ruthenium, nickel, manganese, molybdenum, cobalt, tungsten, uranium, rhodium and palladium can contain. Such halide-containing contact materials have not proven themselves in practice.

In der DE-B2-1719 444 werden elektrischen Kontaktwerkstoffen auf der Basis von Silber und Kupfer auch Karbide, Nitride, Boride und/oder Oxide des Kadmiums, Kupfers, Mangans, Tantals, Zirkoniums, Titans, Molybdäns, Wolframs, Aluminiums und Magnesiums zugesetzt, wobei als weitere Komponente noch Zinnoxid, Zinkoxid, Kupferoxid oder Kobaltoxid zugegen ist. An speziellen Werkstoffkombinationen werden nur AgCdO, AgSn02, AgZnO und AgZnO mit Hartstoffzusatz, wie Zirkoniumdiborid, Tantalkarbid, Wolframkarbid u.ä., erwähnt. Auch diese Kontaktwerkstoffe haben sich in der Praxis nicht bewährt.In DE-B2-1719 444 electrical contact materials based on silver and copper are also added carbides, nitrides, borides and / or oxides of cadmium, copper, manganese, tantalum, zirconium, titanium, molybdenum, tungsten, aluminum and magnesium, tin oxide, zinc oxide, copper oxide or cobalt oxide being present as a further component. On special material combinations, only AgCdO, AgSn0 2 , AgZnO and AgZnO with hard material addition, such as zirconium diboride, tantalum carbide, tungsten carbide and the like, are mentioned. These contact materials have also not proven themselves in practice.

Aufgabe der Erfindung war es nun, einen Werkstoff für elektrische Kontakte aus Silber, Zinnoxid und einem weiteren Metalloxid und ein Verfahren zu seiner Herstellung zu schaffen, der eine hohe Lebensdauer besitzt, eine geringe Verschweißneigung und keine erhöhten Temperaturen beim Schalten zeigt.The object of the invention was to provide a material for electrical contacts made of silver, tin oxide and a further metal oxide and a method for its production which has a long service life, a low tendency to weld and shows no elevated temperatures when switching.

Diese Aufgabe wurde erfindungsgemäß dadurch gelöst, daß der Werkstoff 8-20 Gew.-% Zinnoxid, 0,05-5 Gew.-% Wolframoxid, Rest Silber enthält. Mit diesem Werkstoff tritt überraschenderweise eine starke Reduzierung der Übertemperatur ein, so daß die gleichen, teilweise sogar niedrigere Temperaturen im Schaltgerät als bei Ag/CdO gefunden werden. Auch die Verschweißkräfte von Ag/Sn02 können überraschenderweise durch den Zusatz von Wolframoxid wesentlich vermindert werden.This object was achieved in that the material contains 8-20 wt .-% tin oxide, 0.05-5 wt .-% tungsten oxide, the rest of silver. This material surprisingly results in a large reduction in the excess temperature, so that the same, in some cases even lower, temperatures are found in the switching device than in Ag / CdO. Surprisingly, the welding forces of Ag / Sn0 2 can also be significantly reduced by the addition of tungsten oxide.

Besonders bewährt hat sich ein Werkstoff, der aus 10-15 Gew.-% Zinnoxid, 0,2-1,5 Gew.-% Wolframoxid, Rest Silber besteht. Erstaunlicherweise werden schon durch sehr geringe Wolframoxidgehalte deutliche Verbesserungen hinsichtlich der Übertemperatur und Verschweißkraft erzielt. Besonders gute Ergebnisse erhält man, wenn das Sn02 gleichmäßig ohne Agglomerate eingebracht wird, mit einer Primärkorngröße von < 5 µm.A material which consists of 10-15% by weight of tin oxide, 0.2-1.5% by weight of tungsten oxide and the rest of silver has proven particularly useful. Surprisingly, even very low tungsten oxide contents result in significant improvements in terms of overtemperature and welding force. Particularly good results are obtained if the Sn0 2 is introduced evenly without agglomerates, with a primary grain size of <5 μm.

Diese feine Verteilung der Metalloxidkomponenten kann erreicht werden durch Nachsieben des Sn02 vor dem Mischen, oder besonders vorteilhaft durch Mischen und Kneten der Silber-, Zinnoxid- und Wolframoxidpulver in feuchtem Zustand. Durch das Naßsieben werden Sekundäragglomerate des Sn02 vor dem Mischen entfernt. Bei der Herstellung über Mischen und Kneten im feuchten Zustand werden durch die auftretenden hohen Scherkräfte Sekundäragglomerate zerstört, und damit wird eine gleichmäßige und feinkörnige Verteilung der Komponente bewirkt.This fine distribution of the metal oxide components can be achieved by sieving the Sn0 2 before mixing, or particularly advantageously by mixing and kneading the silver, tin oxide and tungsten oxide powders in a moist state. The wet sieving removes secondary agglomerates of Sn0 2 before mixing. In the production via mixing and kneading in the moist state, secondary agglomerates are destroyed by the high shear forces that occur, and this results in an even and fine-grained distribution of the component.

Es ist für das Schaltverfahren unerheblich, ob Zinnoxid und Wolframoxid durch vorherige Wärmebehandlung zu einem Mischoxid reagieren oder örtlich getrennt im Kontaktwerkstoff vorliegen.It is irrelevant for the switching process whether tin oxide and tungsten oxide react to a mixed oxide by prior heat treatment or whether they are locally separated in the contact material.

Die wesentlichen Verbesserungen im Schaltverhalten, die mit dem erfindungsgemäßen Werkstoff gegenüber Ag/CdO und Ag/Sn02 erreicht wurden, verdeutlicht die folgende Tabelle anhand von Beispielen. Hierzu wurde ein Schaltgerät 3 TB 54 der Firma Siemens verwendet. Die erfindungsgemäßen Werkstoffe wurden pulvermetallurgisch nach Naßkneten mit folgendem Strangpressen hergestellt.The following table illustrates the essential improvements in switching behavior that were achieved with the material according to the invention compared to Ag / CdO and Ag / Sn0 2 using examples. A 3 TB 54 switching device from Siemens was used for this. The materials according to the invention were produced by powder metallurgy after wet kneading with the following extrusion.

(Siehe die Tabelle, Seite 3)(See the table on page 3)

Figure imgb0001
Figure imgb0001

Claims (3)

1. A material for electrical contacts of silver, tin oxide and another metal oxide, characterised in that it contains from 8 to 20 % by weight of tin oxide, from 0.05 to 5 % by weight of tungsten oxide, remainder silver.
2. A material as claimed in Claim 1, characterised in that it contains from 10 to 15 % by weight of tin oxide and from 0.2 to 1.5 % by weight of tungsten oxide.
3. A process for producing the material for electrical contacts claimed in Claims 1 and 2 by sintering a powder-form mixture of the components, characterised in that the powder mixture is kneaded in moist form before sintering.
EP80104820A 1979-08-17 1980-08-14 Material for electric contacts and process for its manufacture Expired EP0024349B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT80104820T ATE2032T1 (en) 1979-08-17 1980-08-14 MATERIAL FOR ELECTRICAL CONTACTS AND PROCESS FOR ITS MANUFACTURE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2933338 1979-08-17
DE2933338A DE2933338C3 (en) 1979-08-17 1979-08-17 Material for electrical contacts and process for their manufacture

Publications (2)

Publication Number Publication Date
EP0024349A1 EP0024349A1 (en) 1981-03-04
EP0024349B1 true EP0024349B1 (en) 1982-12-15

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ID=6078672

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EP80104820A Expired EP0024349B1 (en) 1979-08-17 1980-08-14 Material for electric contacts and process for its manufacture

Country Status (14)

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US (1) US4330330A (en)
EP (1) EP0024349B1 (en)
JP (1) JPS5633444A (en)
AR (1) AR220647A1 (en)
AT (1) ATE2032T1 (en)
AU (1) AU529960B2 (en)
BR (1) BR8005126A (en)
CA (1) CA1149645A (en)
DE (2) DE2933338C3 (en)
ES (1) ES494261A0 (en)
IN (1) IN155263B (en)
MX (1) MX7137E (en)
YU (1) YU41511B (en)
ZA (1) ZA805021B (en)

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3017424A1 (en) * 1980-05-07 1981-11-12 Degussa Ag, 6000 Frankfurt MATERIAL FOR ELECTRICAL CONTACTS
DE3102067A1 (en) * 1981-01-23 1982-08-19 Degussa Ag, 6000 Frankfurt MATERIAL FOR ELECTRICAL CONTACTS
DE3232627A1 (en) * 1981-09-24 1983-04-07 Doduco KG Dr. Eugen Dürrwächter, 7530 Pforzheim Material for electrical contacts
DE3146972A1 (en) * 1981-11-26 1983-06-01 Siemens AG, 1000 Berlin und 8000 München METHOD FOR PRODUCING MOLDED PARTS FROM CADMIUM-FREE SILVER METAL OXIDE COMPOSITIONS FOR ELECTRICAL CONTACTS
US4452651A (en) * 1982-07-08 1984-06-05 Chugai Denki Kogyo K.K. Electrical contact materials and their production method
US4452652A (en) * 1982-07-08 1984-06-05 Akira Shibata Electrical contact materials and their production method
EP0152606B1 (en) * 1984-01-30 1987-09-09 Siemens Aktiengesellschaft Contact material and production of electric contacts
DE3405218A1 (en) * 1984-02-14 1985-09-05 Siemens AG, 1000 Berlin und 8000 München Sintered contact material and method for the preparation thereof
DE3541584A1 (en) * 1985-11-25 1987-05-27 Siemens Ag Process and appliance for preparing metal-composite materials, and contact pieces produced therewith for electrical switchgear
JPH06104873B2 (en) * 1986-07-08 1994-12-21 富士電機株式会社 Silver-metal oxide contact material and manufacturing method thereof
US4904317A (en) * 1988-05-16 1990-02-27 Technitrol, Inc. Erosion resistant Ag-SnO2 electrical contact material
EP0645049B1 (en) * 1992-06-10 1996-04-03 DODUCO GMBH + Co Dr. Eugen DÀ¼rrwächter Material for electrical contacts based on silver-tin oxide or silver-zinc oxide
US5258052A (en) * 1992-06-18 1993-11-02 Advanced Metallurgy Incorporated Powder metallurgy silver-tin oxide electrical contact material
EP0660964B2 (en) * 1992-09-16 2003-01-08 AMI DODUCO GmbH Material for electric contacts based on silver-tin oxide or silver-zinc oxide and process for its production
CN114334503B (en) * 2021-12-24 2022-11-15 佛山市诺普材料科技有限公司 Method for preparing silver tin oxide electrical contact material by low-temperature homogenization and material thereof

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2486341A (en) * 1945-06-30 1949-10-25 Baker & Co Inc Electrical contact element containing tin oxide
DE807416C (en) * 1949-10-20 1951-06-28 Eugen Duerrwaechter Dr Ing Electrical contact material and process for its manufacture
DE1190677B (en) * 1961-01-24 1965-04-08 Engelhard Ind Inc Process for producing electrical contacts by sintering silver powder with the addition of halogens
US3205565A (en) 1963-01-21 1965-09-14 Clevite Corp Sintered rubbing contact material and method for producing same
DE1719444B2 (en) * 1967-10-13 1975-09-04 Veb Keramische Werke Hermsdorf, X 6530 Hermsdorf Process for the production of a dispersion contact material with a silver or copper matrix
DE2306825B2 (en) * 1973-02-12 1977-08-11 National Research Institute For Metals, Tokio ELECTRICAL CONTACT MATERIAL MADE OF AN ALLOY CONTAINING SILVER AND AT LEAST ONE METAL OXIDE
FR2236261A1 (en) * 1973-07-05 1975-01-31 Sumitomo Electric Industries Electrical contacts of silver- indium- and tin- oxides - made by internal oxidn. of silver-indium-tin alloys, and with excellent properties
US3933485A (en) * 1973-07-20 1976-01-20 Chugai Denki Kogyo Kabushiki-Kaisha Electrical contact material
US3933486A (en) * 1974-02-12 1976-01-20 Chugai Denki Kogyo Kabushiki-Kaisha Silver-metal oxide composite and method of manufacturing the same
US4141727A (en) 1976-12-03 1979-02-27 Matsushita Electric Industrial Co., Ltd. Electrical contact material and method of making the same

Also Published As

Publication number Publication date
AR220647A1 (en) 1980-11-14
DE3061351D1 (en) 1983-01-20
US4330330A (en) 1982-05-18
ATE2032T1 (en) 1982-12-15
MX7137E (en) 1987-08-10
DE2933338B2 (en) 1981-06-04
ES8106560A1 (en) 1981-07-01
EP0024349A1 (en) 1981-03-04
BR8005126A (en) 1981-02-24
DE2933338C3 (en) 1983-04-28
ES494261A0 (en) 1981-07-01
AU529960B2 (en) 1983-06-30
JPS5633444A (en) 1981-04-03
JPH0141691B2 (en) 1989-09-07
ZA805021B (en) 1981-08-26
YU199780A (en) 1983-04-30
YU41511B (en) 1987-08-31
IN155263B (en) 1985-01-12
AU6090580A (en) 1981-02-19
DE2933338A1 (en) 1981-02-26
CA1149645A (en) 1983-07-12

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