WO1993006993A1 - Alliages d'argent destines aux revetements de connecteurs electriques - Google Patents

Alliages d'argent destines aux revetements de connecteurs electriques Download PDF

Info

Publication number
WO1993006993A1
WO1993006993A1 PCT/US1992/007731 US9207731W WO9306993A1 WO 1993006993 A1 WO1993006993 A1 WO 1993006993A1 US 9207731 W US9207731 W US 9207731W WO 9306993 A1 WO9306993 A1 WO 9306993A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrical component
coating layer
silver
copper
microns
Prior art date
Application number
PCT/US1992/007731
Other languages
English (en)
Inventor
John G. Cowie
George J. Muench
Julius C. Fister
Original Assignee
Olin Corporation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from US07/767,764 external-priority patent/US5139890A/en
Application filed by Olin Corporation filed Critical Olin Corporation
Publication of WO1993006993A1 publication Critical patent/WO1993006993A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/02—Contacts characterised by the material thereof
    • H01H1/021—Composite material
    • H01H1/023—Composite material having a noble metal as the basic material
    • 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
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/02—Contacts characterised by the material thereof
    • H01H1/021—Composite material
    • H01H1/025—Composite material having copper as the basic material

Definitions

  • This invention relates to silver coatings on electrical components. More particularly, a silver alloy coating layer is deposited on a copper base alloy component to improve both the electrical properties and the oxidation resistance.
  • Electrodes for interconnection systems are usually manufactured from copper or a copper base alloy for high electrical conductivity.
  • a protective coating is usually used to prevent copper oxidation. Copper oxidation is detrimental since copper oxide will increase the contact resistance of the component.
  • One widely used protective coating is gold.
  • Tin and palladium alloys are also widely used. For example, palladium alloys for connector applications are disclosed in a paper by Lees et al, presented at the Twenty Third Annual Connector and Interconnection Technology Symposium and include palladium/25% by weight nickel and palladium/40% by weight silver. Ternary alloys such as palladium/40% silver/5% nickel are also utilized.
  • Silver coatings have also been used to improve conductivity and provide corrosion resistance as disclosed in U.S. Patent No. 4,189,204 to Brown et al.
  • silver As a coating for connector contacts has been limited. Silver is characterized by poor sulfidation resistance and low hardness. However, silver has advantages over gold and a need exists for a reliable silver coating for electrical connector applications. Silver is comparatively inexpensive relative to gold and has high electrical conductivity. The metal is easily deposited by electrolytic means. When silver has been used as a coating material, the coating was usually electrolytically deposited to a thicknesses of from about 1 to about 2.5 microns (about 40-100 microinches) . Silver clads having a thickness in excess of about 25 microns have also been employed. These two thickness characteristics have generally been unacceptable because at the lower limits, the low hardness of silver leads to erosion to the base metal. At the higher thicknesses, both the weight and the cost of the silver become detrimental.
  • a silver coating with sufficient resistance to sulfidation and to wear that the coating is suitable for electrical contact/connector applications. It is a feature of the invention that a coating layer of a silver base alloy minimizes macrowear. Preferred additions to the silver alloy include niobium, zirconium and cobalt. Yet another feature of the invention is that the silver coating may be overcoated with a barrier layer to prevent tarnish.
  • a barrier layer is gold which provides tarnish resistance, lubricity and serves as a barrier to prevent copper migration to the surface of the coating.
  • An advantage of the coatings of the invention is that silver is cheaper than gold and more oxidation resistant than tin.
  • the silver layer is readily deposited by electrolytic means, although cladding and other deposition techniques may also be employed.
  • Yet another advantage is that good oxidation resistance at elevated temperatures is achieved. The resistance to both fretting wear and macrowear is well within the ' " requirements for connector applications.
  • Still another advantage of the invention is that in * high current applications, the thin tarnish layer formed by sulfidation does not detrimentally affect the electrical properties.
  • an electrical component having a copper or copper base alloy substrate and a coating layer contacting the substrate.
  • the coating layer is a silver base alloy containing cobalt, niobium or zirconium. The addition is present in an amount effective to increase the hardness of the coating layer.
  • the electrical components of the invention which have particular utility in connector applications, have a copper or a copper alloy substrate.
  • the component electrical connectors or contacts may be exposed to elevated temperatures in a variety of atmospheres such as under the hood of an automobile. Therefore, copper alloys which resist thermally induced softening are preferred. These alloys include beryllium copper and copper nickel alloys such as copper alloy C7025 (nominal composition 3.0% by weight nickel, 0.6% silicon, 0.1% magnesium and the balance copper).
  • the copper alloy substrate is shaped into a desired ** electrical connector or contact and then coated with a silver base alloy. 5
  • the silver alloy coating layer is deposited by a means which will produce a coating with wear resistance. Wear resistance is necessary because if the silver coating erodes, the copper substrate is exposed to the atmosphere and copper oxide forms.
  • Copper oxide has high electrical resistance and detrimentally affects the performance of the electrical component.
  • the silver alloy coating must further have good electrical conductivity.
  • the electrical resistance both before and after thermal aging must be less than 10 milliohms and preferably less than 2 milliohms.
  • a silver base alloy containing cobalt and having a thickness in the range of from about 1.0 microns (40 micro inches) to about 10 microns (400 micro inches) will meet the above stated requirements. More preferably, the thickness of the silver coating layer is from about 1.5 microns to about 3 microns. Below about 1.0 microns, the connector is prone to macro wear failure due to repeated insertions and withdrawals. When the silver thickness exceeds about 10 microns, the soft coating readily deforms, which can cause mechanical adhesion between the connector and a terminal.
  • the silver alloy layer may be deposited by any means known in the art such as cladding, electrolytic deposition, electroless deposition or vapor deposition.
  • a most preferred means is electrolytic deposition from a cyanide silver bath.
  • an unprotected silver alloy coating layer is not ideal.
  • the silver reacts with sulfur in the air and tarnishes.
  • the tarnish layer is sufficiently thin that relatively high currents, as used in automotive applications, pass through the connector and tarnish does not cause a problem.
  • the electrical resistance of a connector with an unprotected silver layer rises above 10 milliohms.
  • the rise in resistance is eliminated by applying a flash of a first barrier metal such as gold or palladium or an alloy thereof to the external surface of the silver layer.
  • a flash of a first barrier metal such as gold or palladium or an alloy thereof to the external surface of the silver layer.
  • Gold is more preferred and provides at least three benefits:
  • the gold flash is a diffusion barrier further preventing copper atoms from diffusing to the surface and then oxidizing.
  • Gold is considerably more expensive than silver. It is desirable to limit the thickness of the gold flash to that effective to minimize tarnishing. Preferably, the flash is less than about 0.5 microns thick, More preferably, the thickness of the flash is from about 0.05 microns to about 0.1 microns.
  • the gold may be deposited by any suitable means such as electrolytic, electroless or vapor deposition. Electrolytic deposition from a cyanide gold bath is most preferred.
  • a second barrier layer may be disposed between the silver alloy coating layer and the copper alloy substrate.
  • Typical second barrier layers include nickel, iron and chromium. These materials have higher electrical resistance than silver and slightly increase the contact resistance. Also, depending on the diffusion barrier, the formability of the connector may be diminished. Without the second barrier, copper will more readily diffuse into the silver coating. If copper reaches the surface, oxidation occurs. However, the rate of diffusion is sufficiently slow that when thickness of a pure silver coating layer exceeds about 3.5 microns, Applicant has not detected copper at the surface of the coating, even after 3000 hours at 150°C. The diffusion rate of copper through a silver base alloy is expected to be even slower.
  • the wear resistance of the silver coating layer may be further improved by increasing the hardness of the metal through the addition of an additive.
  • Alloys of silver with titanium, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten or mixtures thereof are all believed suitable. More preferred are niobium or zirconium.
  • the concentration of the alloying addition is that effective to increase hardness without unduly reducing the electrical conductivity of the coating layer.
  • the concentration of alloying addition is below about 10 atomic percent. Most preferred is a concentration of from about 1 to about 5 atomic percent.
  • a most preferred alloy addition to the silver base alloy is cobalt.
  • the cobalt should be present in a concentration effective to increase the hardness of the coating layer with out seriously degrading the resistance of the coating to oxidation at the anticipated operating temperatures, up to about 200°C.
  • the maximum acceptable amount of cobalt is less than about 2 percent by weight.
  • a more preferred cobalt range is from about 0.01 to about 1.0 percent by weight and a most preferred cobalt range is from about 0.05 to about 0.3 percent by weight.
  • the binary Ag-Co alloy forms a suitable coating layer, further additions may be made to the alloy in amount up to about 1% by weight each and preferably in amount up to about 0.5% by weight each with a total addition amount below about 2 percent by weight.
  • Suitable additions to the binary alloy are silicon, iron, copper, boron, aluminum, nickel, titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten and palladium.
  • the preferred additions are copper, niobium and palladium which increase the hardness of the Ag-Co ally without seriously degrading the oxidation resistance.
  • Static contact resistance was measured in a accordance with ASTM Standard B667, using a gold probe under dry circuit conditions. The static contact resistance was measured for the as deposited coating and after thermal exposure at 150°C in air for 500, 1000 and 3000 hours. As shown in Table I, an unprotected silver coating layer is effective for thermal exposures up to about 1000 hours. Above 1000 hours, the contact resistance of the coating becomes unacceptably high. With the inclusion of flash of gold over the silver, static contact resistance, even after thermal exposures in excess of 3000 hours, is well below 2 milliohms. TABLE I
  • Thickness Static Contact Resistance (microns) (milliohms) Ag_ Au 0 hr. 500 hr. 1000 hr. 3000 hr.
  • a fretting wear apparatus was employed.
  • the apparatus has an arm which wipes across the test sample. The distance of arm travel and applied load may both be specified.
  • the moving arm simulates the miniscule vibrations which cause fretting corrosion in a contact assembly.
  • a 50 gram load was applied for the fretting wear experiments.
  • Thermal aging was again at 150°C in air for times of up to 3000 hours. Electrical resistivity was continuously monitored by computer and the data printout provided by a chart recorder. The gradual increase in resistance could be determined and the point of failure identified. Results are summarized in Table 2. TABLE 2
  • buttons of binary silver cobalt alloys were prepared by arc melting in a vacuum. The buttons were then tested for hardness. As shown, even for very small additions of cobalt (ie. less than 0.05 percent by weight) ,there was a large increase in hardness (ie. greater than 20%) . By extrapolation, a cobalt content of about 0.3 percent by weight would double the hardness of the coating layer. Alloy Composition Hardness (Rockwell E)

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Contacts (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)

Abstract

On décrit un composant électrique, présentant une bonne résistance à l'oxydation et à l'usure, qui comporte un substrat de cuivre recouvert d'un alliage d'argent. L'argent est combiné avec au moins soit du cobalt, soit du niobium ou du zirconium pour qu'il ait plus de dureté. On peut déposer un placage d'or à la surface externe d'une couche de revêtement en alliage d'argent pour en améliorer les caractéristiques de frottement.
PCT/US1992/007731 1991-09-30 1992-09-15 Alliages d'argent destines aux revetements de connecteurs electriques WO1993006993A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US921,662 1978-07-03
US767,764 1991-09-30
US07/767,764 US5139890A (en) 1991-09-30 1991-09-30 Silver-coated electrical components
US92166292A 1992-07-30 1992-07-30

Publications (1)

Publication Number Publication Date
WO1993006993A1 true WO1993006993A1 (fr) 1993-04-15

Family

ID=27117952

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1992/007731 WO1993006993A1 (fr) 1991-09-30 1992-09-15 Alliages d'argent destines aux revetements de connecteurs electriques

Country Status (2)

Country Link
AU (1) AU2685292A (fr)
WO (1) WO1993006993A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0768729A2 (fr) * 1995-10-16 1997-04-16 General Motors Corporation Contact électrique revêtu
EP1027557A1 (fr) * 1996-07-26 2000-08-16 Catalytica, Inc. Structure de catalyseur chauffe electriquement a combustion et procede de demarrage d'une turbine a gaz utilisant cette structure
WO2013012594A1 (fr) * 2011-07-20 2013-01-24 Tyco Electronics Corporation Contact électrique argenté
US8944838B2 (en) 2013-04-10 2015-02-03 Tyco Electronics Corporation Connector with locking ring
EP3288120A1 (fr) * 2016-08-24 2018-02-28 Robert Bosch GmbH Contact enfichable
CN113166965A (zh) * 2019-01-24 2021-07-23 三菱综合材料株式会社 连接器用端子材及连接器用端子

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1904241A (en) * 1926-12-31 1933-04-18 Kammerer Erwin Compound metal stock
US2241816A (en) * 1940-01-16 1941-05-13 Mallory & Co Inc P R Silver electric contact
US2897584A (en) * 1957-05-22 1959-08-04 Sel Rex Corp Gold plated electrical contact and similar elements
JPS53139173A (en) * 1977-05-11 1978-12-05 Alps Electric Co Ltd Composite contact material
GB2029446A (en) * 1978-06-16 1980-03-19 Nippon Telegraph & Telephone Electrical contact material and method of producing the same
US4502899A (en) * 1981-06-30 1985-03-05 Matsushita Electric Works, Ltd. Electric joint material
US4529667A (en) * 1983-04-06 1985-07-16 The Furukawa Electric Company, Ltd. Silver-coated electric composite materials
JPS61130443A (ja) * 1984-11-29 1986-06-18 Tanaka Kikinzoku Kogyo Kk すり接点材料

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1904241A (en) * 1926-12-31 1933-04-18 Kammerer Erwin Compound metal stock
US2241816A (en) * 1940-01-16 1941-05-13 Mallory & Co Inc P R Silver electric contact
US2897584A (en) * 1957-05-22 1959-08-04 Sel Rex Corp Gold plated electrical contact and similar elements
JPS53139173A (en) * 1977-05-11 1978-12-05 Alps Electric Co Ltd Composite contact material
GB2029446A (en) * 1978-06-16 1980-03-19 Nippon Telegraph & Telephone Electrical contact material and method of producing the same
US4502899A (en) * 1981-06-30 1985-03-05 Matsushita Electric Works, Ltd. Electric joint material
US4529667A (en) * 1983-04-06 1985-07-16 The Furukawa Electric Company, Ltd. Silver-coated electric composite materials
JPS61130443A (ja) * 1984-11-29 1986-06-18 Tanaka Kikinzoku Kogyo Kk すり接点材料

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, Vol. 87, No. 56, issued 1977, (Columbus, Ohio, U.S.A.), BRATERSKAYA et al., "Composite Material Based on Dispersion Hardened Silver", see page 185, Column 1, No. 87: 105321e. *
METALS HANDBOOK, 10th ed., Volume 2, "Properties and Selection: Nonferrous Alloys and Special-Purpose Materials", ASM International, 1990, page 848. *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0768729A2 (fr) * 1995-10-16 1997-04-16 General Motors Corporation Contact électrique revêtu
EP0768729A3 (fr) * 1995-10-16 1998-11-18 General Motors Corporation Contact électrique revêtu
EP1027557A1 (fr) * 1996-07-26 2000-08-16 Catalytica, Inc. Structure de catalyseur chauffe electriquement a combustion et procede de demarrage d'une turbine a gaz utilisant cette structure
EP1027557A4 (fr) * 1996-07-26 2002-05-15 Catalytica Inc Structure de catalyseur chauffe electriquement a combustion et procede de demarrage d'une turbine a gaz utilisant cette structure
WO2013012594A1 (fr) * 2011-07-20 2013-01-24 Tyco Electronics Corporation Contact électrique argenté
US8944838B2 (en) 2013-04-10 2015-02-03 Tyco Electronics Corporation Connector with locking ring
EP3288120A1 (fr) * 2016-08-24 2018-02-28 Robert Bosch GmbH Contact enfichable
CN113166965A (zh) * 2019-01-24 2021-07-23 三菱综合材料株式会社 连接器用端子材及连接器用端子
EP3916133A4 (fr) * 2019-01-24 2022-10-05 Mitsubishi Materials Corporation Matériau de borne de connecteur et terminal de connecteur

Also Published As

Publication number Publication date
AU2685292A (en) 1993-05-03

Similar Documents

Publication Publication Date Title
US5139890A (en) Silver-coated electrical components
US5780172A (en) Tin coated electrical connector
EP0869867B1 (fr) Dispositif de connexion electrique recouvert d'etain
JP3089303B2 (ja) 電気的コネクター対
EP1284301B1 (fr) Revêtements à base d'étain-argent
US6083633A (en) Multi-layer diffusion barrier for a tin coated electrical connector
JP5284526B1 (ja) 電子部品用金属材料及びその製造方法
JP5968668B2 (ja) 電子部品用金属材料
WO2013042572A1 (fr) Matériau métallique pour composants électroniques et son procédé de production
US5139891A (en) Palladium alloys having utility in electrical applications
Pinnel Diffusion-related behaviour of gold in thin film systems
JP2726434B2 (ja) ＳｎまたはＳｎ合金被覆材料
US6641930B2 (en) Electrically conductive metal tape and plug connector
US7015406B2 (en) Electric contact
WO2014054189A1 (fr) Matériau métallique pour composants électroniques et son procédé de production
WO1993006993A1 (fr) Alliages d'argent destines aux revetements de connecteurs electriques
JP2504918B2 (ja) 電気接点要素
JP4427487B2 (ja) 錫被覆電気コネクタ
JPH05267299A (ja) 半導体装置
Lindborg et al. Intermetallic growth and contact resistance of tin contacts after aging
EP0033644A1 (fr) Couche de finition intermétallique d'un connecteur
Sato et al. Palladium with a thin gold layer as a sliding contact material
Antler Effect of fretting on the contact resistance of palladium electroplate having a gold flash, cobalt-gold electroplate, and DG R156
Antler Materials, coatings, and platings
JP2851245B2 (ja) Ｓｎ合金めっき材

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AU BB BG BR CA CS FI HU JP KP KR LK MG MN MW NO PL RO RU SD

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL SE BF BJ CF CG CI CM GA GN ML MR SN TD TG

NENP Non-entry into the national phase

Ref country code: CA

122 Ep: pct application non-entry in european phase