EP1673836B1 - Contact surfaces for electrical contacts - Google Patents

Contact surfaces for electrical contacts Download PDF

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Publication number
EP1673836B1
EP1673836B1 EP04762578A EP04762578A EP1673836B1 EP 1673836 B1 EP1673836 B1 EP 1673836B1 EP 04762578 A EP04762578 A EP 04762578A EP 04762578 A EP04762578 A EP 04762578A EP 1673836 B1 EP1673836 B1 EP 1673836B1
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EP
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Prior art keywords
graphite particles
contact surface
layer
range
surface according
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EP04762578A
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German (de)
French (fr)
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EP1673836A1 (en
Inventor
Peter Rehbein
Volker Haas
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/02—Contact members
    • H01R13/03—Contact members characterised by the material, e.g. plating, or coating materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
    • H01R4/58—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation characterised by the form or material of the contacting members
    • 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
    • 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
    • Y10S428/9335—Product by special process
    • Y10S428/934—Electrical process
    • Y10S428/935—Electroplating
    • 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
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49117—Conductor or circuit manufacturing
    • Y10T29/49204—Contact or terminal manufacturing
    • 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
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49117—Conductor or circuit manufacturing
    • Y10T29/49204—Contact or terminal manufacturing
    • Y10T29/49224—Contact or terminal manufacturing with coating
    • 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
    • Y10T428/12486—Laterally noncoextensive components [e.g., embedded, etc.]
    • 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.]
    • 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.]
    • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
    • Y10T428/12625—Free carbon containing 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
    • Y10T428/12—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
    • Y10T428/12—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
    • Y10T428/12903—Cu-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
    • Y10T428/26—Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
    • Y10T428/263—Coating layer not in excess of 5 mils thick or equivalent
    • Y10T428/264—Up to 3 mils
    • Y10T428/265—1 mil or less

Definitions

  • the invention relates to improved contact surfaces for electrical contacts according to the preamble of the independent claim.
  • Electrical connectors such as sockets and plugs are typically made from a copper-based alloy substrate which provides good electrical conductivity.
  • the substrate is made of a copper-based alloy having high strength and high stress relaxation resistance.
  • cover layer In order to reduce the startup of the copper-base substrate at elevated temperature and to improve solderability, a cover layer is often applied to the substrate.
  • Typical cover layers consist of nickel, palladium / nickel alloys, tin or tin alloys.
  • tin is often used, which is usually hot-dip galvanized or electrodeposited layers in the range of a few ⁇ m. In this case, tin is characterized by its ductility and by its good electrical conductivity.
  • the substrate consists of copper-based alloys such as CuSn 4 bronze, CuNiSi, etc., which often serve as a base material for electrical connectors.
  • copper may diffuse out of the substrate and combine with the tin to form intemal metallic compounds such as Cu 6 Sn 5 and Cu 3 Sn.
  • intemal metallic compounds such as Cu 6 Sn 5 and Cu 3 Sn.
  • the formation of these intermetallic compounds reduces the Amount of unreacted or free tin on the surface. This degrades the electrical, corrosion and other performance characteristics.
  • Thermotin is known as a "tin layer" which is formed by thermal aging and which consists of 100% of inttenetalic phases.
  • thermotin has not yet proven to be a successful solution under all test conditions (e.g., chemical tests or abrasive loading) and therefore has a negligible market share.
  • tin alloys tend due to their low hardness or low wear resistance due to frequent mating or vehicle or engine vibration in the connector easily to increased oxidation (fretting corrosion) and to through. This abrasion or the fretting corrosion can lead to failure of a component (sensor, control unit, electrical components in general).
  • layer abrasion or layer spalling may lead to tribological wear mechanisms of the base material or the intermediate layer (often Cu or Ni) due to poor adhesion.
  • a composite coating for electrical contacts that includes a ductile metal matrix and a uniformly dispersed polymer component.
  • the polymer component is present in a concentration which reduces the frictional forces occurring when a contact is inserted into a corresponding socket.
  • the composite coating has lower friction and improved frictional oxidation as opposed to an electrodeposited tin coating.
  • the US-A 5,916,695 discloses an electrical contact with a copper-based substrate provided with a tin-based capping layer.
  • a barrier layer is applied between the substrate and the cover layer.
  • This barrier layer contains 20 to 40% by weight of nickel and preferably consists mainly of copper (Cu base).
  • the tin-based covering layer may contain additives such as SiO 2 , Al 2 O 3 , SiC, graphite or MoS 2 as lubricants.
  • the DE 4133 466 A1 shows a movable electrical sliding contact having a surface which is in sliding contact with a corresponding mating contact, the surface being coated with a mixture of materials in which graphite particles are dispersed in a matrix of silver.
  • the coating is applied by electroplating, wherein the electroplating liquid is provided with a concentration of metallic silver, calcium cyanide, potassium hydroxide, graphite powder and a dispersing agent for dispersing the graphite powder in the electroplating liquid.
  • the contact surfaces according to the invention have the advantage over the prior art that they require lower insertion forces while the electrical contact is still good.
  • FIG. 1 An embodiment of the invention is illustrated in the drawing and explained in more detail in the following description.
  • the figure shows the arrangement of the graphite particles in an Ag contact layer.
  • the core of the invention is the construction of an Ag covering layer with finely dispersed graphite particles embedded therein on a copper-based substrate for electrical contacts in the automobile, which allows lower insertion forces to be required with consistently good contacting.
  • an Ag contact surface 12 is formed by means of electroplating processes, for example, baths or reel-to-reel processes.
  • the Ag layer may be coated with or without intermediate layers as diffusion barriers, such as undilickeling, and with or without flash of precious metal, such as e.g. Au, Pt, Ru or Pd are deposited.
  • the layer thickness of the deposited Ag layer is according to the invention, depending on the application between about 1.0 and about 10 microns.
  • finely dispersed graphite particles 14 are introduced, for example.
  • the graphite particles are preferably present as platelets or flakes and have a length in the range of 1 to 10 microns, a thickness in the range of 0.05 to 2 microns and a width in the range of 0.05 to 2 microns. It is preferable if the maximum value, ie 2 ⁇ m, does not simultaneously occur with regard to thickness and width.
  • the graphite particles are anisotropically arranged along the plane of habit of the Ag layer, i.e., along the longest axis of the layer plane (see Fig.).
  • the aspect ratio of the graphite particles that is, the length to thickness ratio is 1: 2 to 1:40.
  • the contact surfaces of the invention allow lower insertion forces due to the existing lubricant graphite. Due to the electrical conductivity of the lubricant good contact is guaranteed. Antioxidants contained in the lubricant protect the surface against corrosion, high wear resistance and a high number of mating cycles are obtained.
  • the contact surfaces according to the invention are preferably used in electrical contacts in motor-car connectors.

Description

Die Erfindung betrifft verbesserte Kontaktoberflächen für elektrische Kontakte nach dem Oberbegriff des unabhängigen Anspruches.The invention relates to improved contact surfaces for electrical contacts according to the preamble of the independent claim.

Stand der TechnikState of the art

Elektrische Verbinder wie Buchsen und Stecker werden typischerweise aus einem Substrat aus einer Legierung auf Kupferbasis, das für eine gute elektrische Leitfähigkeit sorgt, hergestellt. Wenn der elektrische Verbinder während des Betriebs erhöhter Temperatur ausgesetzt wird, wie bspw. unter der Motorhaube eines Kraftfahrzeugs, wird das Substrat aus einer Legierung auf Kupferbasis mit hoher Festigkeit und hohem Spannungsrelaxations-Widerstand hergestellt.Electrical connectors such as sockets and plugs are typically made from a copper-based alloy substrate which provides good electrical conductivity. When the electrical connector is exposed to elevated temperature during operation, such as under the hood of a motor vehicle, the substrate is made of a copper-based alloy having high strength and high stress relaxation resistance.

Zur Verringerung des Anlaufens des Substrats aufKupferbasis bei erhöhter Temperatur und zur Verbesserung der Lötbarkeit wird häufig eine Deckschicht auf das Substrat aufgebracht. Typische Deckschichten bestehen aus Nickel, Palladium/Nickel-Legierungen, Zinn oder Zinnlegierungen. Zur Kostenminimierung wird häufig Zinn verwendet, wobei es sich meist um feuerverzinnte oder galvanisch abgeschiedene Schichten im Bereich weniger µm handelt. Hierbei zeichnet sich Zinn durch seine Duktilität sowie durch seine gute elektrische Leitfähigkeit aus.In order to reduce the startup of the copper-base substrate at elevated temperature and to improve solderability, a cover layer is often applied to the substrate. Typical cover layers consist of nickel, palladium / nickel alloys, tin or tin alloys. In order to minimize costs, tin is often used, which is usually hot-dip galvanized or electrodeposited layers in the range of a few μm. In this case, tin is characterized by its ductility and by its good electrical conductivity.

Üblicherweise besteht das Substrat aus Kupfer-Basis-Legierungen wie z.B. CuSn4-Bronze, CuNiSi, usw., die häufig als Grundwerkstoff für elektrische Steckverbindungen dienen. Bei erhöhten Temperaturen kann es dazu kommen, dass Kupfer aus dem Substrat heraus diffundiert und sich mit dem Zinn unter Bildung intemletallischer Verbindungen wie Cu6Sn5 und Cu3Sn vereinigt. Die Bildung dieser intermetallischen Verbindungen verringert die Menge an unreagiertem oder freiem Zinn an der Oberfläche. Dies verschlechtert die elektrischen, Korrosions- und andere Leistungsmerkmale.Usually, the substrate consists of copper-based alloys such as CuSn 4 bronze, CuNiSi, etc., which often serve as a base material for electrical connectors. At elevated temperatures, copper may diffuse out of the substrate and combine with the tin to form intemal metallic compounds such as Cu 6 Sn 5 and Cu 3 Sn. The formation of these intermetallic compounds reduces the Amount of unreacted or free tin on the surface. This degrades the electrical, corrosion and other performance characteristics.

Als Thermozinn ist eine durch Warmauslagerung entstehende "Zinnschicht" bekannt, die zu 100% aus intennetallischen Phasen besteht. Darüber hinaus werden häufig AuCo-Legierungen mit Unternickelung sowie Ag-Oberflächen, z.T. mit Unterkupferung oder Unternickelung, eingesetzt.Thermotin is known as a "tin layer" which is formed by thermal aging and which consists of 100% of inttenetalic phases. In addition, AuCo alloys with nickel plating and Ag surfaces, eg. with sub-copper or nickel-nickel, used.

Thermozinn hat sich bislang jedoch nicht unter allen Prüfbedingungen (z.B., chemische Tests oder abrasive Belastung) als erfolgreiche Lösung herausgestellt und hat daher nur einen vernachlässigbar kleinen Marktanteil.However, thermotin has not yet proven to be a successful solution under all test conditions (e.g., chemical tests or abrasive loading) and therefore has a negligible market share.

Es ist weiterhin bekannt, dass Zinnlegierungen aufgrund ihrer geringen Härte bzw. ihres geringen Verschleißwiderstandes durch häufiges Stecken oder fahrzeug- bzw. motorbedingte Vibrationen im Steckverbinder leicht zur verstärkten Oxidation (Reibkorrosion) und zum Durchrieb neigen. Dieser Durchrieb bzw. die Reibkorrosion können zu einem Ausfall einer Komponente (Sensor, Steuergerät, elektrische Komponenten allgemein) führen.It is also known that tin alloys tend due to their low hardness or low wear resistance due to frequent mating or vehicle or engine vibration in the connector easily to increased oxidation (fretting corrosion) and to through. This abrasion or the fretting corrosion can lead to failure of a component (sensor, control unit, electrical components in general).

Hinzu kommt, dass die Steckkräfte aufgrund der hohen Adhäsionsneigung und der plastischen Verformung für viele Anwendungsfälle wie hochpolige Steckverbinder )> 100 Pins bzw. Kontakte) zu hoch sind. Speziell Oberflächen auf der Basis von Zinn und Silber neigen zur Kaltverschweißung aufgrund von Adhäsion und sind in Selbstpaarungen durch hohe Reibwerte gekennzeichnet (Reibungskoeffizient µ ∼ 1).In addition, because of the high adhesion tendency and the plastic deformation, the insertion forces are too high for many applications such as multi-pin connectors)> 100 pins or contacts). Especially surfaces based on tin and silver are prone to cold welding due to adhesion and are characterized by high coefficients of friction in self-pairing (coefficient of friction μ~1).

Auch bei herkömmlichen Silber- oder Goldschichten kann es bei einem Schichtdurchrieb oder Schichtabplatzern aufgrund schlechter Haftung zu tribologischen Verschleißmechanismen des Grundmaterials oder der Zwischenschicht (häufig Cu oder Ni) kommen.Even with conventional silver or gold layers, layer abrasion or layer spalling may lead to tribological wear mechanisms of the base material or the intermediate layer (often Cu or Ni) due to poor adhesion.

Aufgrund der Altautorichtlinie EG 2000/53 ist es untersagt, bleihaltige Zinnschichten zu verwenden. Da das Blei die Whiskerbildung (Whisker sind winzige haarförmige Kristalle) hemmt, kommt es bei galvanischem Reinzinn verstärkt zum Whiskerwachstum, was zu Kurzschlüssen führen kann.Due to the old car directive EG 2000/53 it is forbidden to use tin layers containing lead. Since lead inhibits whisker formation (whiskers are tiny hair-shaped crystals), galvanic pure tin increasingly causes whisker growth, which can lead to short circuits.

In der US-A-5,028,492 wird eine Kompositbeschichtung für elektrische Kontakte beschrieben, die eine duktile Metallmatrix und eine gleichförmig verteilte Polymerkomponente beinhaltet. Dabei liegt die Polymerkomponente in einer Konzentration vor, die die beim Einstecken eines Kontakts in eine entsprechende Fassung auftretenden Reibkräfte reduziert. Die Kompositbeschichtung weist eine geringere Reibung und eine verbesserte Reiboxidation im Gegensatz zu einer galvanisch abgeschiedenen Zinnbeschichtung auf.In the US-A-5,028,492 For example, a composite coating for electrical contacts is described that includes a ductile metal matrix and a uniformly dispersed polymer component. In this case, the polymer component is present in a concentration which reduces the frictional forces occurring when a contact is inserted into a corresponding socket. The composite coating has lower friction and improved frictional oxidation as opposed to an electrodeposited tin coating.

Die US-A 5,916,695 offenbart einen elektrischen Kontakt mit einem kupferbasierten Substrat, das mit einer zinnbasierten Deckschicht versehen ist. Um die Diffusion des Kupfers aus dem Substrat in die Deckschicht und die damit verbundene Bildung von intermetallischen Schichten zu verhindern, wird zwischen dem Substrat und der Deckschicht eine Sperrschicht aufgebracht. Diese Sperrschicht enthält 20 bis 40 Gew.-% Nickel und besteht vorzugsweise hauptsächlich aus Kupfer (Cu-Basis). Die zinnbasierte Deckschicht kann u.a. Zusätze wie SiO2, Al2O3, SiC, Graphit oder MoS2 als Schmierstoffe enthalten.The US-A 5,916,695 discloses an electrical contact with a copper-based substrate provided with a tin-based capping layer. In order to prevent the diffusion of the copper from the substrate into the cover layer and the associated formation of intermetallic layers, a barrier layer is applied between the substrate and the cover layer. This barrier layer contains 20 to 40% by weight of nickel and preferably consists mainly of copper (Cu base). The tin-based covering layer may contain additives such as SiO 2 , Al 2 O 3 , SiC, graphite or MoS 2 as lubricants.

Die DE 4133 466 A1 zeigt einen bewegbaren elektrischen Schleifkontakt mit einer Oberfläche, die mit einem entsprechenden Gegenkontakt in Gleitkontakt ist, wobei die Oberfläche mit einem Materialgemisch beschichtet ist, bei welchem Graphitteilchen in einer Matrix aus Silber dispergiert sind. Die Beschichtung ist durch Elektroplattieren aufgebracht, wobei die Elektroplattierflüssigkeit mit einer Konzentration von metallischem Silber, Kalziumzyanid, Kaliumhydroxid, Graphitpulver und einem Dispergiermittel zum Dispergieren des Graphitpulvers in der Elektroplattierflüssigkeit versehen ist.The DE 4133 466 A1 shows a movable electrical sliding contact having a surface which is in sliding contact with a corresponding mating contact, the surface being coated with a mixture of materials in which graphite particles are dispersed in a matrix of silver. The coating is applied by electroplating, wherein the electroplating liquid is provided with a concentration of metallic silver, calcium cyanide, potassium hydroxide, graphite powder and a dispersing agent for dispersing the graphite powder in the electroplating liquid.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäßen Kontaktoberflächen haben gegenüber dem Stand der Technik den Vorteil, dass sie bei weiterhin guter elektrischer Kontaktierung niedrigere Steckkräfte erfordern.The contact surfaces according to the invention have the advantage over the prior art that they require lower insertion forces while the electrical contact is still good.

Weiterhin ist vorteilhaft, dass sie durch den Gehalt an Antioxidanzien im enthaltenen Schmierstoff einen Schutz der Oberfläche vor Korrosion bieten.Furthermore, it is advantageous that they provide protection of the surface from corrosion by the content of antioxidants in the lubricant contained.

Außerdem ergibt sich der Vorteil eines erhöhten Verschleißschutzes und somit einer Lebensdauererhöhung der Kontakte.In addition, there is the advantage of increased wear protection and thus an increase in the service life of the contacts.

Vorteilhafte Weiterbildungen der Erfindung ergeben sich aus den in den Unteransprüchen genannten Maßnahmen.Advantageous developments of the invention will become apparent from the measures mentioned in the dependent claims.

Kurze Beschreibung der ZeichnungShort description of the drawing

Ein Ausführungsbeispiele der Erfindung ist in der Zeichnung dargestellt und in der nachfolgenden Beschreibung näher erläutert. Die Figur zeigt die Anordnung der Graphitteilchen in einer Ag-Kontaktschicht.An embodiment of the invention is illustrated in the drawing and explained in more detail in the following description. The figure shows the arrangement of the graphite particles in an Ag contact layer.

Ausführungsbeispieleembodiments

Kern der Erfindung ist der Aufbau einer Ag-Deckschicht mit darin eingebetteten feindispersen Graphitteilchen auf einem kupferbasierten Substrat für elektrische Kontakte im Automobil, die es erlaubt, dass bei gleichbleibend guter Kontaktierung niedrigere Steckkräfte erforderlich sind.The core of the invention is the construction of an Ag covering layer with finely dispersed graphite particles embedded therein on a copper-based substrate for electrical contacts in the automobile, which allows lower insertion forces to be required with consistently good contacting.

Wie in der Figur gezeigt, wird zunächst auf dem elektrischen Kontakt, d.h., auf dem kupferbasierten Substrat 10 eine Ag-Kontaktoberfläche 12 mittels galvanischer Verfahren, bspw. Bäder oder reel-to-reel-Verfahren, erzeugt.As shown in the figure, first on the electrical contact, that is, on the copper-based substrate 10, an Ag contact surface 12 is formed by means of electroplating processes, for example, baths or reel-to-reel processes.

Die Ag-Schicht kann mit oder auch ohne Zwischenschichten als Diffusionsbarrieren, wie Untemickelung, sowie mit oder ohne Flash aus Edelmetall wie z.B. Au, Pt, Ru oder Pd abgeschieden werden.The Ag layer may be coated with or without intermediate layers as diffusion barriers, such as undilickeling, and with or without flash of precious metal, such as e.g. Au, Pt, Ru or Pd are deposited.

Die Schichtdicke der abgeschiedenen Ag-Schicht liegt erfindungsgemäß, je nach Anwendung zwischen etwa 1,0 und etwa 10 µm.The layer thickness of the deposited Ag layer is according to the invention, depending on the application between about 1.0 and about 10 microns.

In die Ag-Schicht sind feindisperse Graphitteilchen 14 eingebracht, bspw. durch Verwirbelung von Graphit und chemischen Hilfsstoffen zum Einbinden (Netzmittel), wobei die Graphitmengen im Bereich von 1 bis 3 Gew.-% Kohlenstoff der Ag-Schicht bzw. im Bereich von 3 bis 10 Flächen-% Kohlenstoff liegen. Die Graphitteilchen liegen bevorzugt als Plättchen oder Flakes vor und haben eine Länge im Bereich von 1 bis 10 µm, eine Dicke im Bereich von 0,05 bis 2 µm und eine Breite im Bereich von 0,05 bis 2 µm. Bevorzugt ist, wenn bzgl. Dicke und Breite nicht gleichzeitig der maximale Wert, also 2 µm, auftritt.In the Ag layer finely dispersed graphite particles 14 are introduced, for example. By turbulence of graphite and chemical excipients for binding (wetting agent), wherein the amounts of graphite in the range of 1 to 3 wt .-% carbon of the Ag layer or in the range of 3 up to 10 area% carbon. The graphite particles are preferably present as platelets or flakes and have a length in the range of 1 to 10 microns, a thickness in the range of 0.05 to 2 microns and a width in the range of 0.05 to 2 microns. It is preferable if the maximum value, ie 2 μm, does not simultaneously occur with regard to thickness and width.

Die Graphitteilchen sind anisotrop entlang der Habitusebene der Ag-Schicht, d.h., entlang der längsten Achse der Schichtebene angeordnet (vgl. Fig.).The graphite particles are anisotropically arranged along the plane of habit of the Ag layer, i.e., along the longest axis of the layer plane (see Fig.).

Das Aspektverhältnis der Graphitteilchen, d.h., das Verhältnis Länge zu Dicke beträgt 1:2 bis 1:40.The aspect ratio of the graphite particles, that is, the length to thickness ratio is 1: 2 to 1:40.

Die erfindungsgemäßen Kontaktoberflächen erlauben niedrigere Steckkräfte aufgrund des vorhandenen Schmierstoffs Graphit. Aufgrund der elektrischen Leitfähigkeit des Schmierstoffes ist eine gute Kontaktierung gewährleistet. Im Schmiermittel enthaltene Antioxidanzien schützen die Oberfläche vor Korrosion, es wird eine hohe Verschleißbeständigkeit sowie eine hohe Steckzyklenzahl erhalten.The contact surfaces of the invention allow lower insertion forces due to the existing lubricant graphite. Due to the electrical conductivity of the lubricant good contact is guaranteed. Antioxidants contained in the lubricant protect the surface against corrosion, high wear resistance and a high number of mating cycles are obtained.

Die erfindungsgemäßen Kontaktoberflächen finden bevorzugt Verwendung in elektrischen Kontakte in motomahen Automobilsteckverbindungen.The contact surfaces according to the invention are preferably used in electrical contacts in motor-car connectors.

Claims (6)

  1. Contact surface for electrical contacts, wherein a silver layer deposited by means of electroplating processes is disposed on a copper-based substrate, wherein the silver layer contains finely dispersed graphite particles in a quantity which amounts to 1 to 3% by weight of the silver layer, and wherein the length of the graphite particles is in the range from 0.5 to 20 µm, characterized in that the graphite particles are arranged anisotropically along the habit plane of the silver layer, the thickness to length ratio of the graphite particles being in the range from 1:2 to 1:40.
  2. Contact surface according to Claim 1, characterized in that the length of the graphite particles is in the range from 1 to 10 µm.
  3. Contact surface according to Claim 1 or 2, characterized in that the thickness of the graphite particles is in the range from 0.05 to 2 µm.
  4. Contact surface according to one of the preceding claims, characterized in that the layer thickness of the Ag layer is in the range from about 1 to about 10 µm.
  5. Contact surface according to one of the preceding claims, characterized in that the graphite particles do not simultaneously have the maximum thickness and width.
  6. Use of the contact surface according to one of the preceding claims for electrical contacts in automotive plug connections in close proximity to the engine.
EP04762578A 2003-10-06 2004-08-03 Contact surfaces for electrical contacts Active EP1673836B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10346206A DE10346206A1 (en) 2003-10-06 2003-10-06 Contact surface e.g. for motor vehicle electrical contacts in engine bay, has silver layer with finely dispersed graphite particles
PCT/DE2004/001733 WO2005046000A1 (en) 2003-10-06 2004-08-03 Contact surfaces for electrical contacts

Publications (2)

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EP1673836A1 EP1673836A1 (en) 2006-06-28
EP1673836B1 true EP1673836B1 (en) 2010-10-13

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US (1) US7638721B2 (en)
EP (1) EP1673836B1 (en)
DE (2) DE10346206A1 (en)
WO (1) WO2005046000A1 (en)

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Also Published As

Publication number Publication date
EP1673836A1 (en) 2006-06-28
DE502004011782D1 (en) 2010-11-25
US20070275611A1 (en) 2007-11-29
US7638721B2 (en) 2009-12-29
WO2005046000A1 (en) 2005-05-19
DE10346206A1 (en) 2005-04-28

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