EP0225912A1 - Nickel-based electrical contact device - Google Patents
Nickel-based electrical contact deviceInfo
- Publication number
- EP0225912A1 EP0225912A1 EP86903756A EP86903756A EP0225912A1 EP 0225912 A1 EP0225912 A1 EP 0225912A1 EP 86903756 A EP86903756 A EP 86903756A EP 86903756 A EP86903756 A EP 86903756A EP 0225912 A1 EP0225912 A1 EP 0225912A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- contact
- hydrogen
- nickel
- amount
- surface region
- 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.)
- Ceased
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
- H01B1/02—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of metals or alloys
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R43/00—Apparatus or processes specially adapted for manufacturing, assembling, maintaining, or repairing of line connectors or current collectors or for joining electric conductors
- H01R43/16—Apparatus or processes specially adapted for manufacturing, assembling, maintaining, or repairing of line connectors or current collectors or for joining electric conductors for manufacturing contact members, e.g. by punching and by bending
Definitions
- the invention is concerned with devices having an electrically conducting member having electrical contact surface of nickel-based materials.
- a material consisting essentially of nickel and a controlled amount of hydrogen has contact properties comparable to those of gold such as, in particular, low and stable contact resistance.
- Preferred amounts of hydrogen in nickel are regarded to be such as to associate atoms of hydrogen with nickel atoms on dislocations, thus blocking oxidation at critical sites.
- surface contact resistance of the material is significantly less than 100 milliohms even after prolonged exposure to an oxidizing ambient.
- FIG. 1 is a perspective view of an electrical connector device in accordance with the invention.
- FIG. 2 is a schematic cross-sectional view of a portion of a device in accordance with the invention. Detailed Description
- the electrical connector device shown in FIG. 1 comprises housing 11 and contact pins 12.
- Housing 11 ismade of an electrically insulating material, and contact pins 12 have contact surfaces in accordance with the invention.
- FIG. 2 Shown in FIG. 2 are, in cross section, an electrically conducting member 21 on which layer 22 is situated.
- Member 21 may consist of a copper conductor material, and surface layer 22 is a nickel material which comprises hydrogen at least in a surface region 23.
- the incorporation of controlled amounts of hydrogen into nickel material results in enhanced contact properties such as low contact resistance and long-term stability of such resistance.
- Hydrogen may be incorporated in a nickel material in a variety of ways such as, e.g., in the course of electroplating, by sputtering in an argon-hydrogen atmosphere, and by indiffusion at a bulk surface which, preferably, has been subjected to plastic deformation by cold working.
- Preferred concentrations of hydrogen depend on conditions under which layers or bodies of nickel are produced and processed, and it is postulated that preferred concentrations increase in direct relationship with the cumber of nickel atoms on dislocations. In particular, greater amounts of hydrogen are beneficial for cold worked material, preferred amounts being directly related to level of cold working.
- nickel material is plastically deformed by a significant amount, such as, e.g., corresponding to at least 50 percent reduction of cross-sectional area prior to hydrogen diffusion, the latter being carried out at a temperature which is less than the recrystallization temperature of Ni.
- Hydrogen indiffusion is typically effected over a time of a few minutes, and indiffusion is facilitated by heating at a temperature below the recrystallization temperature of Ni.
- cold-worked material are those involving the use of microscopic flakes dispersed or embedded in a non-conductive matrix material as, e.g., in electrically conducting inks, pastes, and adhesives.
- hydrogen can be incorporated in nickel layers by electroplating out of a suitable nickel bath, solutions of nickel salts being considered most suitable where the anion is but weakly oxidizing.
- a contact material of the invention may be free or essentially free of elements other than nickel and hydrogen, impurities may be present and additional elements may be included such as, e.g., boron, silicon, germanium, phosphorus, arsenic, antimony, cr bismuth. When present in solid solution or, in other words, when incorporated in the nickel structure, impurities and additives are considered not to interfere with the beneficial effect of hydrogen in nickel. Amounts of at least 70 atom percent nickel-hydrogen are preferred in the contact material.
- Contacts of the invention may receive a final coating of "flash" comprising a significant amount of a coating material such as gold, one or several platinum-group elements, or gold and one or several platinum-group elements, the amount being sufficient to impart to the coated surface the appearance of such coating material.
- the structure of such coating may be essentially homogeneous or layered, and coating thickness typically is in a range from 0.01 to 0.05 micrometer.
- a cobalt-hardened gold coating may be electro-deposited from a slightly acidic solution (pH 5) comprising potassium gold cyanide, cobalt citride, and a citric buffer. (The presence of cobalt, nominally in a range of from 0.2 to 0.5 percent by weight, enhances surface hardness especially in the case of thicker coatings.)
- Preferred temperature of the plating bath is approximately 35 degrees C, and a plating current of approximately
- Example 1 A layer having a thickness of approximately 1.68 micrometer and having approximately 0.005 atom concentration of hydrogen in nickel was deposited on a copper substrate by sputtering from an essentially pure nickel target in an atmosphere of approximately 10 percent by volume hydrogen, remainder essentially argon. The layer was exposed to atmospheric test conditions at 75 degrees C and 95 percent relative humidity for 65 hours.
- Example 2 A layer having a thickness of approximately 0.48 micrometer was deposited as further described in Example 1 above. Ultimate contact resistance was in the range of from 10 to 13 milliohms.
- Example 3 A layer having a thickness of approximately 4.5 micrometers was deposited on a copper substrate by electroplating from a 2-molar nickel chloride solution at a temperature of approximately 75 degrees C, pH of the solution was approximately 3 as obtained by the addition of ammonium hydroxide, and current density during deposition was approximately 150 milliamperes/cm 2 . The layer was exposed to atmospheric test conditions as described in Example 1 above, and contact resistance was determined to be in the range of from 1 to 10 milliohms.
- Example 4 A layer was deposited as described in
- Example 3 above except that a 2-molar nickel citrate solution was used at a pH of approximately 6. Contact resistance of the layer was found to be in the range of from 0.3 to 10 milliohms.
- Example 5 A layer was deposited as described in Example 3 above except that a 1/2-molar nickel acetate solution was used at a pH of approximately 8. Contact resistance of the layer was in the range of from 2 to 15 milliohms.
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Contacts (AREA)
- Electroplating Methods And Accessories (AREA)
Abstract
Dispositif comprenant un élément électroconducteur ayant une surface de contact formée d'un matériau de contact à base de nickel. Selon l'invention, le matériau à base de nickel, au moins sur une région de la surface (par exemple 23), comprend des quantités mesurées d'hydrogène et présente une faible résistance au contact électrique même après avoir été longtemps exposé à une atmosphère oxydante. Lorsqu'il est utilisé comme couche de surface (par exemple 22) sur un élément électroconducteur (par exemple 21), un tel matériau se prête bien comme matériau de contact et représente une alternative bon marché à l'or. Et, lorsqu'il est préparé sous la forme de lamelles microscopiques, ledit matériau est approprié pour être utilisé dans des encres et des adhésifs électroconducteurs.Device comprising an electrically conductive element having a contact surface formed of a nickel-based contact material. According to the invention, the nickel-based material, at least over a region of the surface (for example 23), comprises measured quantities of hydrogen and has a low resistance to electrical contact even after having been exposed to an atmosphere for a long time. oxidizing. When used as a surface layer (e.g. 22) on an electrically conductive element (e.g. 21), such a material lends itself well as a contact material and represents a cheap alternative to gold. And, when prepared in the form of microscopic coverslips, said material is suitable for use in inks and electroconductive adhesives.
Description
NICKEL-BASED ELECTRICAL CONTACT DEVICE
Technical Field
The invention is concerned with devices having an electrically conducting member having electrical contact surface of nickel-based materials. Background of the Invention
Typically, the manufacture of high-quality electrical contacts has involved the usage of gold whose properties of low contact resistance and high chemical stability are key advantages in such usage. However, as the price of gold remains high, efforts continue at finding alternative materials for contact manufacture. Prominent among such alternatives are precious metals other than gold; e.g., silver-palladium alloys have been found suitable for certain applications.
While such alternate alloys are less expensive than gold, still further cost reduction is desired, and nonprecious metal alloys such as, e.g., copper-nickel alloys have been investigated for contact resistance and stability over time. See S. M. Garte et al., "Contact Properties of Nickel-Containing Alloys", Electrical Contacts, 1972, Illinois Institute of Technology. Summary of the Invention
It has been discovered that a material consisting essentially of nickel and a controlled amount of hydrogen has contact properties comparable to those of gold such as, in particular, low and stable contact resistance. Preferred amounts of hydrogen in nickel are regarded to be such as to associate atoms of hydrogen with nickel atoms on dislocations, thus blocking oxidation at critical sites. Typically, surface contact resistance of the material is significantly less than 100 milliohms even after prolonged exposure to an oxidizing ambient.
Brief Description of. the Drawing
FIG. 1 is a perspective view of an electrical connector device in accordance with the invention; and
FIG. 2 is a schematic cross-sectional view of a portion of a device in accordance with the invention. Detailed Description
The electrical connector device shown in FIG. 1 comprises housing 11 and contact pins 12. Housing 11 ismade of an electrically insulating material, and contact pins 12 have contact surfaces in accordance with the invention.
Shown in FIG. 2 are, in cross section, an electrically conducting member 21 on which layer 22 is situated. Member 21 may consist of a copper conductor material, and surface layer 22 is a nickel material which comprises hydrogen at least in a surface region 23. The incorporation of controlled amounts of hydrogen into nickel material results in enhanced contact properties such as low contact resistance and long-term stability of such resistance.
Hydrogen may be incorporated in a nickel material in a variety of ways such as, e.g., in the course of electroplating, by sputtering in an argon-hydrogen atmosphere, and by indiffusion at a bulk surface which, preferably, has been subjected to plastic deformation by cold working. Preferred concentrations of hydrogen depend on conditions under which layers or bodies of nickel are produced and processed, and it is postulated that preferred concentrations increase in direct relationship with the cumber of nickel atoms on dislocations. In particular, greater amounts of hydrogen are beneficial for cold worked material, preferred amounts being directly related to level of cold working. In the case of electrodeposited layers, preferred amounts are in the range of from 0.0004 to 0.0009 atom concentration of hydrogen in nickel; when severe cold work is applied up to 0.01 atom concentration is preferred.
Fortuitously, as dislocation slip bands produced by cold working also facilitate indiffusion of hydrogen, contact properties of cold-worked bulk nickel material are most favorably affected by hydrogen indiffusion. Accordingly, applications are preferred in which nickel material is plastically deformed by a significant amount, such as, e.g., corresponding to at least 50 percent reduction of cross-sectional area prior to hydrogen diffusion, the latter being carried out at a temperature which is less than the recrystallization temperature of Ni. Hydrogen indiffusion is typically effected over a time of a few minutes, and indiffusion is facilitated by heating at a temperature below the recrystallization temperature of Ni. Among applications of cold-worked material are those involving the use of microscopic flakes dispersed or embedded in a non-conductive matrix material as, e.g., in electrically conducting inks, pastes, and adhesives.
Conveniently, hydrogen can be incorporated in nickel layers by electroplating out of a suitable nickel bath, solutions of nickel salts being considered most suitable where the anion is but weakly oxidizing.
While a contact material of the invention may be free or essentially free of elements other than nickel and hydrogen, impurities may be present and additional elements may be included such as, e.g., boron, silicon, germanium, phosphorus, arsenic, antimony, cr bismuth. When present in solid solution or, in other words, when incorporated in the nickel structure, impurities and additives are considered not to interfere with the beneficial effect of hydrogen in nickel. Amounts of at least 70 atom percent nickel-hydrogen are preferred in the contact material.
Contacts of the invention may receive a final coating of "flash" comprising a significant amount of a coating material such as gold, one or several platinum-group elements, or gold and one or several platinum-group
elements, the amount being sufficient to impart to the coated surface the appearance of such coating material. The structure of such coating may be essentially homogeneous or layered, and coating thickness typically is in a range from 0.01 to 0.05 micrometer. For example, a cobalt-hardened gold coating may be electro-deposited from a slightly acidic solution (pH 5) comprising potassium gold cyanide, cobalt citride, and a citric buffer. (The presence of cobalt, nominally in a range of from 0.2 to 0.5 percent by weight, enhances surface hardness especially in the case of thicker coatings.) Preferred temperature of the plating bath is approximately 35 degrees C, and a plating current of approximately
5 milliamperes per cm2 is convenient. Typical plating times are of the order of half a minute. Prior to plating, a surface may be cleaned, e.g., by electrolytic scrubbing in an alkaline solution, rinsing in de-ionized water, and dipping in dilute hydrochloric acid at elevated temperature. Example 1. A layer having a thickness of approximately 1.68 micrometer and having approximately 0.005 atom concentration of hydrogen in nickel was deposited on a copper substrate by sputtering from an essentially pure nickel target in an atmosphere of approximately 10 percent by volume hydrogen, remainder essentially argon. The layer was exposed to atmospheric test conditions at 75 degrees C and 95 percent relative humidity for 65 hours. After such exposure contact resistance was determined to be in the range of from 7 to 10 milliohms. Example 2. A layer having a thickness of approximately 0.48 micrometer was deposited as further described in Example 1 above. Ultimate contact resistance was in the range of from 10 to 13 milliohms. Example 3. A layer having a thickness of approximately 4.5 micrometers was deposited on a copper substrate by electroplating from a 2-molar nickel chloride solution at a temperature of approximately 75 degrees C, pH of the
solution was approximately 3 as obtained by the addition of ammonium hydroxide, and current density during deposition was approximately 150 milliamperes/cm2. The layer was exposed to atmospheric test conditions as described in Example 1 above, and contact resistance was determined to be in the range of from 1 to 10 milliohms.
Example 4. A layer was deposited as described in
Example 3 above except that a 2-molar nickel citrate solution was used at a pH of approximately 6. Contact resistance of the layer was found to be in the range of from 0.3 to 10 milliohms.
Example 5. A layer was deposited as described in Example 3 above except that a 1/2-molar nickel acetate solution was used at a pH of approximately 8. Contact resistance of the layer was in the range of from 2 to 15 milliohms.
Claims
1. Device comprising an electrically conducting member having a contact surface, said contact surface being the surface of a surface region of said member and consisting of a contact material,
CHARACTERIZED IN THAT an amount of at least 70 atom percent of said contact material consists of nickel and hydrogen, said hydrogen being present in said amount in a significant small percentage so as to enhance an electrical contact property of said contact surface.
2. Device according to claim 1, CHARACTERIZED IN THAT hydrogen atoms in said contact material being in correspondence with nickel atoms on dislocations.
3. The method according to claim 1, CHARACTERIZED IN THAT said surface region being an electrodeposited layer in which atom concentration of hydrogen in said amount is in the range of from 0.0004 to 0.0009.
4. Device according to claim 1, CHARACTERIZED IN THAT said surface region being a layer which has been plastically deformed and in which atom concentration of hydrogen in said amount is in the range of from 0.0004 to 0.01.
5. Device according to claim 4, CHARACTERIZED IN THAT said surface region has been plastically deformed so as to result in cross-sectional area reduction greater than or equal to 50 percent.
6. Device according to claim 1, CHARACTERIZED IN THAT the contact resistance at said surface is less than 100 milliohms.
7. Device according to claim 1, CHARACTERIZED IN THAT said contact surface is essentially the entire surface of said member.
8. Device according to claim 7,
CHARACTERIZED IN THAT said member is a contact pin.
9. Device according to claim 7, CHARACTERIZED IN THAT said member is a conductive particle.
10. Device according to claim 9 , CHARACTERIZED IN THAT said particle is an ink particle.
11. Device according to claim 9, CHARACTERIZED IN THAT said particle is embedded in a non-conductive matrix material.
12. Device according to claim 11, CHARACTERIZED IN THAT said non-conductive matrix material is an adhesive material.
13. Device according to claim 1, CHARACTERIZED IN THAT said contact material has a surface coating which consists essentially of a coating material selected from the group consisting of gold, one or several platinum-group elements, and gold and one or several platinum-group elements.
14. Device according to claim 13, CHARACTERIZED IN THAT the amount of said coating material being sufficient to produce a surface appearance of said coating material.
15. Apparatus according to claim 13, CHARACTERIZED IN THAT said surface coating has a thickness in the range of from 0.01 to 0.05 micrometer.
16. Method for making a device having an electrically conducting member, comprising a step of providing said member with a contact surface which is the surface of surface region of a contact material, CHARACTERIZED BY producing said contact material so that at least a surface region thereof comprise an amount of at least 70 atom percent of nickel and hydrogen, with hydrogen being present in said amount in a significant small percentage so as to enhance an electrical contact property of said contact surface.
17. Method according to claim 16,
CHARACTERIZED BY conducting said step as a step of electrodepositing or a step or sputtering or a step of diffusion of hydrogen into nickel.
18. Method of claim 17,
CHARACTERIZED BY cold working said member prior to diffusion.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US73577985A | 1985-05-20 | 1985-05-20 | |
| US735779 | 1985-05-20 | ||
| US82398686A | 1986-01-30 | 1986-01-30 | |
| US823986 | 1986-01-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP0225912A1 true EP0225912A1 (en) | 1987-06-24 |
Family
ID=27112944
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP86903756A Ceased EP0225912A1 (en) | 1985-05-20 | 1986-05-02 | Nickel-based electrical contact device |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0225912A1 (en) |
| KR (1) | KR880700503A (en) |
| CA (1) | CA1260099A (en) |
| WO (1) | WO1986007205A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4732821A (en) * | 1986-01-30 | 1988-03-22 | American Telephone And Telegraph Company, At&T Bell Laboratories | Nickel-based electrical contact |
| US4934968A (en) * | 1986-12-22 | 1990-06-19 | Amp Incorporated | Nickel plated contact surface having preferred crystallographic orientation |
| WO1988004701A1 (en) * | 1986-12-22 | 1988-06-30 | Amp Incorporated | Nickel plated contact surface having preferred crystallographic orientation |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4361470A (en) * | 1974-09-03 | 1982-11-30 | Micro-Plate, Inc. | Connector contact point |
| GB2097426B (en) * | 1981-04-24 | 1984-01-18 | James John Gilbert | Electro-plating process and products therefrom |
-
1986
- 1986-05-02 WO PCT/US1986/000971 patent/WO1986007205A1/en not_active Application Discontinuation
- 1986-05-02 EP EP86903756A patent/EP0225912A1/en not_active Ceased
- 1986-05-02 KR KR1019870700029A patent/KR880700503A/en not_active Application Discontinuation
- 1986-05-20 CA CA000509516A patent/CA1260099A/en not_active Expired
Non-Patent Citations (1)
| Title |
|---|
| See references of WO8607205A1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CA1260099A (en) | 1989-09-26 |
| KR880700503A (en) | 1988-03-15 |
| WO1986007205A1 (en) | 1986-12-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
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| AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): BE DE GB NL |
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| 17P | Request for examination filed |
Effective date: 19870507 |
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| 17Q | First examination report despatched |
Effective date: 19911028 |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED |
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| 18R | Application refused |
Effective date: 19920502 |
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| RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: ROBBINS, MURRAY Inventor name: PLEWES, JOHN, TRAVIS Inventor name: HAUSER, JOACHIM, JACQUES |