SE1100035A1 - Electrical contact element - Google Patents
Electrical contact element Download PDFInfo
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- SE1100035A1 SE1100035A1 SE1100035A SE1100035A SE1100035A1 SE 1100035 A1 SE1100035 A1 SE 1100035A1 SE 1100035 A SE1100035 A SE 1100035A SE 1100035 A SE1100035 A SE 1100035A SE 1100035 A1 SE1100035 A1 SE 1100035A1
- Authority
- SE
- Sweden
- Prior art keywords
- contact
- silver
- layer
- contact element
- friction
- Prior art date
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- 229910052709 silver Inorganic materials 0.000 claims abstract description 52
- 239000004332 silver Substances 0.000 claims abstract description 52
- 239000002114 nanocomposite Substances 0.000 claims abstract description 27
- 239000000463 material Substances 0.000 claims abstract description 21
- -1 silver halide Chemical class 0.000 claims abstract description 17
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 35
- 229910052751 metal Inorganic materials 0.000 claims description 32
- 239000002184 metal Substances 0.000 claims description 32
- 239000011159 matrix material Substances 0.000 claims description 30
- 229910003481 amorphous carbon Inorganic materials 0.000 claims description 14
- XMBWDFGMSWQBCA-UHFFFAOYSA-N hydrogen iodide Chemical compound I XMBWDFGMSWQBCA-UHFFFAOYSA-N 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 5
- 239000010949 copper Substances 0.000 claims description 4
- 238000001704 evaporation Methods 0.000 claims description 4
- 230000008020 evaporation Effects 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims description 4
- 229910052723 transition metal Inorganic materials 0.000 claims description 4
- 150000003624 transition metals Chemical class 0.000 claims description 4
- CPELXLSAUQHCOX-UHFFFAOYSA-M Bromide Chemical compound [Br-] CPELXLSAUQHCOX-UHFFFAOYSA-M 0.000 claims description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 3
- 238000007598 dipping method Methods 0.000 claims description 3
- 150000004820 halides Chemical class 0.000 claims description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 229910052758 niobium Inorganic materials 0.000 claims description 2
- 239000010955 niobium Substances 0.000 claims description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 2
- 230000000737 periodic effect Effects 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 239000010410 layer Substances 0.000 description 78
- JKFYKCYQEWQPTM-UHFFFAOYSA-N 2-azaniumyl-2-(4-fluorophenyl)acetate Chemical compound OC(=O)C(N)C1=CC=C(F)C=C1 JKFYKCYQEWQPTM-UHFFFAOYSA-N 0.000 description 14
- 229910021612 Silver iodide Inorganic materials 0.000 description 14
- 229940045105 silver iodide Drugs 0.000 description 14
- 238000000576 coating method Methods 0.000 description 12
- 239000000314 lubricant Substances 0.000 description 10
- 239000011248 coating agent Substances 0.000 description 9
- 239000002245 particle Substances 0.000 description 9
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 8
- 229910052799 carbon Inorganic materials 0.000 description 8
- 239000004065 semiconductor Substances 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000005229 chemical vapour deposition Methods 0.000 description 4
- 229910052736 halogen Inorganic materials 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 238000005137 deposition process Methods 0.000 description 3
- 150000002367 halogens Chemical class 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 230000002269 spontaneous effect Effects 0.000 description 3
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 description 2
- 229910021607 Silver chloride Inorganic materials 0.000 description 2
- 239000011247 coating layer Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000000356 contaminant Substances 0.000 description 2
- 229910052740 iodine Inorganic materials 0.000 description 2
- 239000011630 iodine Substances 0.000 description 2
- 229910001507 metal halide Inorganic materials 0.000 description 2
- 150000005309 metal halides Chemical class 0.000 description 2
- 229910010271 silicon carbide Inorganic materials 0.000 description 2
- ADZWSOLPGZMUMY-UHFFFAOYSA-M silver bromide Chemical compound [Ag]Br ADZWSOLPGZMUMY-UHFFFAOYSA-M 0.000 description 2
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- 229910001316 Ag alloy Inorganic materials 0.000 description 1
- 229910018540 Si C Inorganic materials 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910002056 binary alloy Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000009396 hybridization Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 229910003465 moissanite Inorganic materials 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
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
-
- 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
Landscapes
- Contacts (AREA)
Abstract
Ett elektriskt kontaktelement (1, 5, 14, 15, 16, 21, 22) för att bilda elektrisk kontakt med ett kontaktorgan (2, 6, 7) för att möjliggöra att en elektrisk ström flyter mellan nämnda kontakt element och nämnda kontaktorgan, nämnda kontakt element innefattar en kropp (3) som har åtminstone en av sina kontaktytor belagd med ett kontaktskikt (4) som skall påföras nämnda kontaktorgan, varvid kontaktskiktet (4) innefattar ett silverlegerat MAX-fas material, eller en silverlegerad nanokomposit. Kontaktskiktet är åtminstone delvis belagt med ett friktionssänkande skikt (13, 19, 23, 26, 27) innefattande en silverhalogenid.(Fig. 1)An electrical contact element (1, 5, 14, 15, 16, 21, 22) to form electrical contact with a contact means (2, 6, 7) to enable an electric current to flow between said contact element and said contact means, said contact element comprises a body (3) which has at least one of its contact surfaces coated with a contact layer (4) to be applied to said contact means, wherein the contact layer (4) comprises a silver-alloyed MAX-phase material, or a silver-alloyed nanocomposite. The contact layer is at least partially coated with a friction-reducing layer (13, 19, 23, 26, 27) comprising a silver halide. (Fig. 1)
Description
15 20 25 30 35 2 absorbs contaminants, for example particles of dust, which may give an increased contact resistance. The contaminants in the lubricant may also lead to the lubricant oxidizing more easily and thus becoming less durable. 15 20 25 30 35 2 absorbs contaminants, for example particles of dust, which may give an increased contact resistance. The contaminants in the lubricant may also lead to the lubricant oxidizing more easily and thus becoming less durable.
An electrical contact coating layer of MAX-phase type or a nano-composite, such as a nanocomposite film comprising a matrix of amorphous carbon and crystallites of nano- size, i.e. with dimensions in the range of 1-100 nm, of at least one metal carbide embedded therein, has a dry friction coefficient that is substantially lower than metallic contact materials such as silver. Such a contact layer is described in patent application EP 1934995 Al, hereby incorporated by reference. However, in some applications, there is a demand to improve the friction and wear properties of the contact layer even further, and grease- or oil based lubricants are not suitable due to insufficient long-term stability.An electrical contact coating layer of MAX-phase type or a nano-composite, such as a nanocomposite film comprising a matrix of amorphous carbon and crystallites of nano-size, i.e. with dimensions in the range of 1-100 nm, or at least one metal carbide embedded therein, has a dry friction coefficient that is substantially lower than metallic contact materials such as silver. Such a contact layer is described in patent application EP 1934995 A1, hereby incorporated by reference. However, in some applications, there is a demand to improve the friction and wear properties of the contact layer even further, and grease- or oil based lubricants are not suitable due to insufficient long-term stability.
One object of the invention is to achieve an electrical contact element with a contact coating layer of MAX-phase type or a nano-composite film, such as a nanocomposite film comprising a matrix of amorphous carbon and crystallites of nano-size, and comprising a friction-reducing layer without the above-mentioned disadvantages when using a fat- or oil- based lubricant for friction-reducing purposes. The friction-reducing layer shall have a low friction at the contact surfaces, a good resistance to wear and a high corrosion resistance.One object of the invention is to achieve an electrical contact element with a contact coating layer of MAX-phase type or a nano-composite film, such as a nanocomposite film comprising a matrix of amorphous carbon and crystallites of nano-size, and comprising a friction-reducing layer without the above-mentioned disadvantages when using a fat- or oil-based lubricant for friction-reducing purposes. The friction-reducing layer shall have a low friction at the contact surfaces, a good resistance to wear and a high corrosion resistance.
The friction-reducing layer shall also be simple and inexpensive to manufacture.The friction-reducing layer shall also be simple and inexpensive to manufacture.
SUMMARY OF THE INVENTION According to one aspect of the invention said object is achieved by an electrical contact element having the features defined in claim l.SUMMARY OF THE INVENTION According to one aspect of the invention said object is achieved by an electrical contact element having the features defined in claim l.
An electric contact element for making an electric contact to a contact member for enabling an electric current to flow between said contact element and said contact member, said contact element comprising a body having at least one contact surface thereof coated with a contact layer to be applied against said contact member. The contact layer comprises a silver-alloyed MAX-phase-material, or a silver-alloyed nanocomposite, and the contact layer is at least partially coated with a friction-reducing layer comprising a silver halogenide.An electric contact element for making an electric contact to a contact member for enabling an electric current to fl ow between said contact element and said contact member, said contact element comprising a body having at least one contact surface thereof coated with a contact layer to be applied against said contact member. The contact layer comprises a silver-alloyed MAX-phase-material, or a silver-alloyed nanocomposite, and the contact layer is at least partially coated with a friction-reducing layer comprising a silver halide.
The silver alloyed MAX-phase-material, or silver alloyed nanocomposite film has a matrix of amorphous carbon and crystallites of nano-size, i.e. with dimensions in the range of 1- 100 nm, of at least one metal carbide embedded in the matrix. The silver is present as silver particles in the matrix and silver is segregating to the surface of the nanocomposite when it 10 15 20 25 30 35 3 is exposed to ions of a halogenide and form a low-friction layer comprising a silver halogenide.The silver alloyed MAX-phase-material, or silver alloyed nanocomposite fi lm has a matrix of amorphous carbon and crystallites of nano-size, i.e. with dimensions in the range of 1- 100 nm, or at least one metal carbide embedded in the matrix. The silver is present as silver particles in the matrix and silver is segregating to the surface of the nanocomposite when it 10 15 20 25 30 35 3 is exposed to ions of a halide and form a low-friction layer comprising a silver halide.
The silver in the silver alloyed contact layer is arranged in a phase embedded in carbon of said matrix and separated with respect to carbon of said matrix. The friction-reducing layer arranged on the contact layer has a thickness which is in the interval of from 0.001 um to 1000 um and preferably is smaller than 5 um. Examples of silver halogenides are silver iodide, silver chloride or silver bromide.The silver in the silver alloyed contact layer is arranged in a phase embedded in carbon of said matrix and separated with respect to carbon of said matrix. The friction-reducing layer arranged on the contact layer has a thickness which is in the interval of from 0.001 um to 1000 um and preferably is smaller than 5 um. Examples of silver halides are silver iodide, silver chloride or silver bromide.
The silver alloyed MAX-phase-material, or silver alloyed nanocomposite film has properties making it excellently suited to be used as such a contact layer. This is due to the nature of the matrix of amorphous carbon allowing a physical adaption of the interface surface of the contact layer to a corresponding or other contact layer on said contact member combined with the metal carbide crystallites embedded therein reducing the resistivity of the contact layer with respect to the layer being only of amorphous carbon. Furthermore, the presence of the metal carbide in said matrix or binding phase of amorphous carbon increases the wear resistance of the contact layer. Such a nanocomposite film has also the potential for a low friction coefficient with respect to a said contact member. However the friction properties could be further improved according to the present invention.The silver alloyed MAX-phase-material, or silver alloyed nanocomposite film has properties making it excellently suited to be used as such a contact layer. This is due to the nature of the matrix of amorphous carbon allowing a physical adaptation of the interface surface of the contact layer to a corresponding or other contact layer on said contact member combined with the metal carbide crystallites embedded therein reducing the resistivity of the contact layer with respect to the layer being only of amorphous carbon. Furthermore, the presence of the metal carbide in said matrix or binding phase of amorphous carbon increases the wear resistance of the contact layer. Such a nanocomposite film also has the potential for a low friction coefficient with respect to a said contact member. However the friction properties could be further improved according to the present invention.
According to one exemplary embodiment a silver-alloyed MAX-phase coating of Ti-Si-C or a silver alloyed nanocomposite of Ti-C is exposed to iodine and the silver content in the contact layer segregates to the surface and spontaneously reacts with the iodine to form a solid lubricating silver iodide layer on top of the coating.According to one exemplary embodiment a silver-alloyed MAX-phase coating of Ti-Si-C or a silver alloyed nanocomposite of Ti-C is exposed to iodine and the silver content in the contact layer segregates to the surface and spontaneously reacts with the iodine to form a solid lubricating silver iodide layer on top of the coating.
A contact element according to the invention exhibits a reduced friction for the contact surfaces, an improved resistance to wear, and an increased corrosion resistance of the contact surfaces compared with a non-coated contact layer of silver-alloyed MAX-phase- material, or a silver-alloyed nanocomposite of TiC In case of low friction at the contact surfaces, the operation of the contact element is facilitated and enables the use of higher contact forces. A low friction at the contact surfaces also results in increased resistance to wear, which leads to improved electrical and thennal properties and increases the expected service life.A contact element according to the invention exhibits a reduced friction for the contact surfaces, an improved resistance to wear, and an increased corrosion resistance of the contact surfaces compared with a non-coated contact layer of silver-alloyed MAX-phase- material, or a silver-alloyed nanocomposite of TiC In case of low friction at the contact surfaces, the operation of the contact element is facilitated and enables the use of higher contact forces. A low friction at the contact surfaces also results in increased resistance to wear, which leads to improved electrical and thennal properties and increases the expected service life.
“Matrix” is in this disclosure and with regard to the contact layer is to be interpreted to not only relate to a continuous majority phase in which particles of carbide and particles of silver are contained. The carbon matrix may also be a minority phase and not even continuous, and this matrix may in the extreme case only consist of a few atomic layers 10 15 20 25 30 35 4 around the carbide grains and silver particles. Thus, the matrix is to be interpreted as this type of binding phase.“Matrix” is in this disclosure and with regard to the contact layer is to be interpreted to not only relate to a continuous majority phase in which particles of carbide and particles of silver are contained. The carbon matrix may also be a minority phase and not even continuous, and this matrix may in the extreme case only consist of a few atomic layers 10 15 20 25 30 35 4 around the carbide grains and silver particles. Thus, the matrix is to be interpreted as this type of binding phase.
The different properties of the matrix of amorphous carbon and the nano-size crystallites of metal carbide makes it of course possible to optimize the contact layer for each intended use of the contact element by changing primarily the metal carbide/carbon matrix ratio. The hardness of the contact layer will increase with an increasing such ratio, while the resistivity thereof will decrease with an increasing metal carbide/carbon matrix ratio. However, the contact resistance will change With an increasing such ratio.The different properties of the amorphous carbon matrix and the nano-size crystallites of metal carbide makes it of course possible to optimize the contact layer for each intended use of the contact element by changing primarily the metal carbide / carbon matrix ratio. The hardness of the contact layer will increase with an increasing such ratio, while its resistivity will decrease with an increasing metal carbide / carbon matrix ratio. However, the contact resistance will change with an increasing such ratio.
The metal of the metal carbide is preferably a transition metal, i.e. an element from Group 3 to 12 of the periodic table. It has been found that such a metal gives the contact layer excellent properties especially with respect to a low contact resistance. As an example of metals well suited for said nano-size metal carbides niobium and titanium may be mentioned. Preferably the carbide is TiC.The metal of the metal carbide is preferably a transition metal, i.e. an element from Group 3 to 12 of the periodic table. It has been found that such a metal gives the contact layer excellent properties especially with respect to a low contact resistance. As an example of metals well suited for said nano-size metal carbides niobium and titanium may be mentioned. Preferably the carbide is TiC.
According to one embodiment the silver-alloyed film comprises only one metal to form the metal carbide, i.e. there is a binary system. It has turned out that it is mostly sufficient to have only one metal fonning a metal carbide embedded in said matrix of amorphous carbon for obtaining the properties of the contact layer aimed at.According to one embodiment the silver-alloyed film comprises only one metal to form the metal carbide, i.e. there is a binary system. It has turned out that it is mostly sufficient to have only one metal fonning a metal carbide embedded in said matrix of amorphous carbon for obtaining the properties of the contact layer aimed at.
According to another embodiment of the invention said silver-alloyed film comprises crystallites of nano-size of a carbide of at least one further, second metal. This metal may advantageously be a transition metal. It has been found that the addition of such a second metal improves the possibilities to adapt the properties of the contact layer to the demands put on the contact element in the intended use. Sometimes a very low contact resistance is more important than a high resistance to wear or conversely, and this may then be addressed by adding such a second metal. The so-called metal carbide properties of the nanocomposite film may be improved through the addition of this further carbide forming metal.According to another embodiment of the invention said silver-alloyed film comprises crystallites of nano-size of a carbide of at least one further, second metal. This metal may advantageously be a transition metal. It has been found that the addition of such a second metal improves the possibilities to adapt the properties of the contact layer to the demands put on the contact element in the intended use. Sometimes a very low contact resistance is more important than a high resistance to wear or conversely, and this may then be addressed by adding such a second metal. The so-called metal carbide properties of the nanocomposite film may be improved through the addition of this further carbide forming metal.
According to another embodiment of the invention said crystallites have a diameter-like dimension in the range of 5-50 nm. It has turned out that this size of the crystallites results in particularly advantageous Characteristics often asked for in a contact layer of this type.According to another embodiment of the invention said crystallites have a diameter-like dimension in the range of 5-50 nm. It has turned out that this size of the crystallites results in particularly advantageous Characteristics often asked for in a contact layer of this type.
According to one embodiment of the invention the thickness of said contact layer film is in the range of 0.05-10 um, Which is suitable for most applications.According to one embodiment of the invention the thickness of said contact layer film is in the range of 0.05-10 um, Which is suitable for most applications.
The coating with the silver halogenide is carried out, for example, electrolytically directly on contact-layer of the silver-alloyed MAX-phase-material, or the silver-alloyed nanocomposite of TiC material. The silver halogenide is preferably silver iodide that is 10 15 20 25 30 35 5 formed by a spontaneous reaction between silver and iodide by exposing the contact layer, at which silver has segregated, to I' ions. Thereby a simple and inexpensive deposition process is provided.The coating with the silver halide is carried out, for example, electrolytically directly on contact-layer of the silver-alloyed MAX-phase-material, or the silver-alloyed nanocomposite of TiC material. The silver halide is preferably silver iodide that is 10 15 20 25 30 35 5 formed by a spontaneous reaction between silver and iodide by exposing the contact layer, at which silver has segregated, to I 'ions. Thereby a simple and inexpensive deposition process is provided.
The coating of the silver halogenide could also obtained by dipping the contact element into a solution comprising at least one of the following ions: chloride, bromide or iodide.The coating of the silver halide could also be obtained by dipping the contact element into a solution comprising at least one of the following ions: chloride, bromide or iodide.
The halogen reacts with the silver present at the contact surface and forms the layer of the silver halogenide.The halogen reacts with the silver present at the contact surface and forms the layer of the silver halide.
Another possible coating method is evaporation. During evaporation, the contact element is placed in a closed chamber and a gas comprising at least one of the halogens is released into the chamber. The halogen reacts with silver, in the silver-alloyed MAX-phase-material, or the silver-alloyed nanocomposite, that has segregated to the surface of the contact element and thereby forms a solid compound of silver halogenide on at least part of the contact surface. The silver halogenide is preferably silver iodide that is formed by a spontaneous reaction between silver and iodide by exposing the contact layer, at which silver has segregated, to 12 vapor. Thereby a simple and inexpensive deposition process is provided.Another possible coating method is evaporation. During evaporation, the contact element is placed in a closed chamber and a gas comprising at least one of the halogens is released into the chamber. The halogen reacts with silver, in the silver-alloyed MAX-phase-material, or the silver-alloyed nanocomposite, that has segregated to the surface of the contact element and thereby forms a solid compound of silver halogen on at least part of the contact surface. The silver halide is preferably silver iodide that is formed by a spontaneous reaction between silver and iodide by exposing the contact layer, at which silver has segregated, to 12 vapor. Thereby a simple and inexpensive deposition process is provided.
A further example of a coating process which may be used is CVD (Chemical Vapour Deposition). In the CVD process, the material with which the whole of, or parts of, the contact surface is to be coated is evaporated. By a chemical reaction on or in the vicinity of that surface which is to be coated, a solid layer is formed on the surface. By means of the CVD process, the layer is given a uniform thickness with a low porosity.A further example of a coating process which may be used is CVD (Chemical Vapor Deposition). In the CVD process, the material with which the whole of, or parts of, the contact surface is to be coated is evaporated. By a chemical reaction on or in the vicinity of that surface which is to be coated, a solid layer is formed on the surface. By means of the CVD process, the layer is given a uniform thickness with a low porosity.
One advantage of coating the contact surface with a layer of a chemical compound as a silver halogenide, compared with using a grease- or oil-based lubricant according to the prior art, is that the layer with the metal halogenide has a longer durability than the layer with the fat- or oil-based lubricant. The silver halogenide provide a good adhesion to silver surfaces, is mechanically strong with a low friction coefficient, and is thermodynamically stable up to approximately 300°C. Another advantage is that the contact element is lighter to handle after the coating with the metal halogenide than after the coating with the fat- or oil-based lubricant. The fat- or oil-based lubricant is volatile and easily creeps to surfaces which should be free from lubricant. Additional advantages of the layer of the silver halo- genide are that a more uniform layer may be obtained and that the layer has better adhesion to the contact surface comprising silver than the layer of the fat- or oil-based lubricant.One advantage of coating the contact surface with a layer of a chemical compound as a silver halide, compared with using a grease- or oil-based lubricant according to the prior art, is that the layer with the metal halide has a longer durability than the layer with the fat- or oil-based lubricant. The silver halide provides good adhesion to silver surfaces, is mechanically strong with a low friction coefficient, and is thermodynamically stable up to approximately 300 ° C. Another advantage is that the contact element is lighter to handle after the coating with the metal halide than after the coating with the fat- or oil-based lubricant. The fat- or oil-based lubricant is volatile and easily creeps to surfaces which should be free from lubricant. Additional advantages of the layer of the silver halogen- genide are that a more uniform layer may be obtained and that the layer has better adhesion to the contact surface comprising silver than the layer of the fat- or oil-based lubricant.
Preferably the contact element is arranged to provide current transmission in switchgear for low voltage, medium voltage or high voltage, in a control system or in some form of electric circuit. 10 15 20 25 30 35 BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically illustrates an electric contact element according to an embodiment of the invention, Figure 2 shows, in a section, an electrical contact element of helical contact type, Figure 3 schematically shows a contact arrangement according to the present invention in a disconnector , Figure 4 schematically shows a sliding contact arrangement in a tap changer of a transformer according to an embodiment of the invention, Figure 5 schematically shows a contact arrangement according to the present invention in a relay, Figure 6 is a partially sectioned and exploded view of an arrangement for making an electric contact to a semiconductor chip according to another embodiment of the invention, Figure 7 schematically shows the material structure of a contact layer of silver alloyed MAX-phase, or silver-alloyed nanocomposite, contact layer, and Figure 8 schematically shows the material structure of a contact layer of silver-alloyed MAX-phase, or silver-alloyed nanocomposite, with a friction reducing layer applied on the contact surface.Preferably the contact element is arranged to provide current transmission in switchgear for low voltage, medium voltage or high voltage, in a control system or in some form of electric circuit. 10 15 20 25 30 35 BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically illustrates an electric contact element according to an embodiment of the invention, Figure 2 shows, in a section, an electrical contact element of helical contact type, Figure 3 schematically shows a contact arrangement according to the present invention in a disconnector, Figure 4 schematically shows a sliding contact arrangement in a tap changer of a transformer according to an embodiment of the invention, Figure 5 schematically shows a contact arrangement according to the present invention in a relay, Figure 6 is a partially sectioned and exploded view of an arrangement for making an electric contact to a semiconductor chip according to another embodiment of the invention, Figure 7 schematically shows the material structure of a contact layer of silver alloyed MAX-phase, or silver-alloyed nanocomposite, contact layer, and Figure 8 schematically shows the material structure of a contact layer of silver-alloy ed MAX-phase, or silver-alloyed nanocomposite, with a friction reducing layer applied on the contact surface.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Figure 1 schematically shows a contact element 1 forming an electric contact to a contact member 2 for enabling an electric current to flow between said contact element and the contact member. The contact element comprises a body 3, which may be for instance of aluminium or copper, or an alloy based on any of these two metals, and that has at least one contact surface thereof coated with a contact layer 4 to be applied against said contact member 2. The contact layer 4 is at least partly coated with a friction-reducing layer 27 of silver iodide. The contact layer 4 typically has a thickness of 0.05-10 um, and the friction- reducing layer 27 typically has a thickness of 0.()0l-l um. The thicknesses of the contact layer and the friction reducing layer shown in Fig 1 are exaggerated with respect to other dimensions of the contact element and the contact member for illustrating purposes. 10 15 20 25 30 35 Figure 2 shows another example of a contact device in which it is advantageous to coat at least one of the contact surfaces of the contact layer with a friction-reducing layer according to the invention. This embodiment relates to a helical contact arrangement having a contact element 5 in the form of a spring-loaded annular body, such as a ring of a helically wound wire, adapted to connect and maintain an electric contact to a first contact member 6, such as an inner sleeve or a pin, and a second contact member 7, such as an outer sleeve or a tube. The contact element 5 is, in a contact state, compressed such that at least a contact surface 8 thereof will bear spring-loadedly against the contact surface 9 of the first contact member 6 and at least another contact surface 10 of the first contact element 5 will bear spring-loadedly against at least a contact surface ll of the second contact member 7.DESCRIPTION OF THE PREFERRED EMBODIMENTS Figure 1 schematically shows a contact element 1 forming an electric contact to a contact member 2 for enabling an electric current to fl ow between said contact element and the contact member. The contact element comprises a body 3, which may be for instance of aluminum or copper, or an alloy based on any of these two metals, and that has at least one contact surface thereof coated with a contact layer 4 to be applied against said contact member 2. The contact layer 4 is at least partly coated with a friction-reducing layer 27 of silver iodide. The contact layer 4 typically has a thickness of 0.05-10 um, and the friction- reducing layer 27 typically has a thickness of 0. () 0l-l um. The thicknesses of the contact layer and the friction reducing layer shown in Fig 1 are exaggerated with respect to other dimensions of the contact element and the contact member for illustrating purposes. 10 15 20 25 30 35 Figure 2 shows another example of a contact device in which it is advantageous to coat at least one of the contact surfaces of the contact layer with a friction-reducing layer according to the invention. This embodiment relates to a helical contact arrangement having a contact element 5 in the form of a spring-loaded annular body, such as a ring of a helically wound wire, adapted to connect and maintain an electric contact to a first contact member 6, such as an inner sleeve or a pin, and a second contact member 7, such as an outer sleeve or a tube. The contact element 5 is, in a contact state, compressed such that at least one contact surface 8 thereof will bear spring-loadedly against the contact surface 9 of the first contact member 6 and at least another contact surface 10 of the first contact element 5. will bear spring-loadedly against at least a contact surface ll of the second contact member 7.
According to this embodiment of the invention at least one of the contact surfaces 8-11 is completely or partially coated with a silver-alloyed MAX-phase-material film, or a silver alloyed nanocomposite film, which in tum is completely or partly coated with a friction- reducing layer comprising a silver halogenide, such as silver iodide. The helical contact element is used, for example, in an electric circuit breaker in a switchgear unit.According to this embodiment of the invention at least one of the contact surfaces 8-11 is completely or partially coated with a silver-alloyed MAX-phase-material film, or a silver alloyed nanocomposite film, which in tum is completely or partly coated with a friction-reducing layer comprising a silver halide, such as silver iodide. The helical contact element is used, for example, in an electric circuit breaker in a switchgear unit.
Fig 3 illustrates very schematically how an electric contact arrangement according to the invention may be arranged in a disconnector 12. A friction reducing layer 13 of silver iodide is arranged on a contact layer of a silver-alloyed MAX-phase-material film, or a silver alloyed nanocomposite film, having a matrix of amorphous carbon and nano-size crystallites of metal carbide and silver particles embedded in the matrix. The film is arranged on at least one of the contact surfaces of two contact elements 14, 15 movable with respect to each other for establishing an electric contact there between and obtaining a visible disconnection of the contact elements.Fig 3 illustrates very schematically how an electric contact arrangement according to the invention may be arranged in a disconnector 12. A friction reducing layer 13 of silver iodide is arranged on a contact layer of a silver-alloyed MAX-phase-material fi lm, or a silver alloyed nanocomposite fi lm, having a matrix of amorphous carbon and nano-size crystallites of metal carbide and silver particles embedded in the matrix. The film is arranged on at least one of the contact surfaces of two contact elements 14, 15 movable with respect to each other for establishing an electric contact there between and obtaining a visible disconnection of the contact elements.
Fi g 4 illustrates schematically a sliding electric contact arrangement according to another embodiment of the invention, in which the contact element 16 is a movable part of a tap changer 17 of a transformer adapted to slide in electric contact along contacts 18 to the secondary winding of the transformer, accordingly forming the contact member, for tapping voltage of a level desired from said transformer. A friction reducing layer 19 comprising silver iodide is arranged on a contact layer of a silver-alloyed MAX-phase-material film, or a silver alloyed nanocomposite film, having a matrix of amorphous carbon and nano-size crystallites of metal carbide and silver particles embedded in the matrix. The contact film layer is arranged on the contact surface of the contact element 16 and/or on the contact member 18. The contact element 16 may in this way be easily moved along the winding while maintaining a low resistance contact thereto. 10 15 20 25 30 35 8 Figure 5 illustrates very schematically a contact arrangement according to another embodiment of the invention used in a relay 20, and one or both of the contact surfaces of opposite contact elements 21, 22 may be provided with a contact layer having a friction reducing layer 23 according to the invention, which will result in less wear of the contact surface and make them corrosion resistant as a consequence of the character of said contact layer material.Fi g 4 illustrates schematically a sliding electric contact arrangement according to another embodiment of the invention, in which the contact element 16 is a movable part of a tap changer 17 of a transformer adapted to slide in electric contact along contacts 18 to the secondary winding of the transformer, accordingly forming the contact member, for tapping voltage of a level desired from said transformer. A friction reducing layer 19 comprising silver iodide is arranged on a contact layer of a silver-alloyed MAX-phase-material film, or a silver alloyed nanocomposite film, having a matrix of amorphous carbon and nano-size crystallites of metal carbide and silver particles embedded in the matrix. The contact film layer is arranged on the contact surface of the contact element 16 and / or on the contact member 18. The contact element 16 may in this way be easily moved along the winding while maintaining a low resistance contact thereto. 10 15 20 25 30 35 8 Figure 5 illustrates very schematically a contact arrangement according to another embodiment of the invention used in a relay 20, and one or both of the contact surfaces of opposite contact elements 21, 22 may be provided with a contact layer having a friction reducing layer 23 according to the invention, which will result in less wear of the contact surface and make them corrosion resistant as a consequence of the character of said contact layer material.
An arrangement for making good electric contact to a semiconductor component 24 is illustrated in Fi g 6, but the different members arranged in a stack and pressed together with a high pressure, preferably exceeding 1 MPa and typically 6-8 MPa, are shown spaced apart for clarity. Each half of the stack comprises a pool piece 25 in the form of a Cu plate for making a connection to the semiconductor component. Each pool piece is provided with a a silver-alloyed MAX-phase-material film, or a silver alloyed nanocomposite film, having a matrix of amorphous carbon and nano-size crystallites of a metal carbide and silver particles embedded in the matrix, and having a friction reducing layer of silver iodide 26 according to the invention. The coefficient of thermal expansion of the semiconductor material, for instance Si, SiC or diamond, of the semiconductor component and of Cu differs a lot (2.2 x 106/K fen si and 16 x itró/K for cn), whieh means that the cn piates 25 and the semiconductor component 24 will move laterally with respect to each other when the temperature thereof changes.An arrangement for making good electric contact to a semiconductor component 24 is illustrated in Fig. G 6, but the different members arranged in a stack and pressed together with a high pressure, preferably exceeding 1 MPa and typically 6-8 MPa, are shown spaced apart for clarity. Each half of the stack comprises a pool piece 25 in the form of a Cu plate for making a connection to the semiconductor component. Each pool piece is provided with aa silver-alloyed MAX-phase-material film, or a silver alloyed nanocomposite film, having a matrix of amorphous carbon and nano-size crystallites of a metal carbide and silver particles embedded in the matrix, and having a friction reducing layer of silver iodide 26 according to the invention. The coefficient of thermal expansion of the semiconductor material, for instance Si, SiC or diamond, of the semiconductor component and of Cu differs a lot (2.2 x 106 / K fen si and 16 x itró / K for cn), whieh means that the cn piates 25 and the semiconductor component 24 will move laterally with respect to each other when the temperature thereof changes.
Figure 7 shows the contact layer 4 comprising a nanocomposite film having a matrix 28 of amorphous carbon and crystallites 29 of nano-size, i.e. with dimensions in the range of 1- 100 nm, of at least one metal carbide embedded therein. The metal is preferably a transition metal. The hybridization of the amorphous carbon matrix, i.e. how the carbon is bound to itself within the matrix, is preferably characterized by a high sp2/sp3 ratio, which makes the matrix more graphite-like than diamond-like. Silver particles 30 are added to the nanocomposite and is being arranged in a phase embedded in carbon of the matrix and separated with respect to the carbon of the matrix.Figure 7 shows the contact layer 4 comprising a nanocomposite film having a matrix 28 of amorphous carbon and crystallites 29 of nano-size, i.e. with dimensions in the range of 1- 100 nm, or at least one metal carbide embedded therein. The metal is preferably a transition metal. The hybridization of the amorphous carbon matrix, i.e. how the carbon is bound to itself within the matrix, is preferably characterized by a high sp2 / sp3 ratio, which makes the matrix more graphite-like than diamond-like. Silver particles 30 are added to the nanocomposite and is being arranged in a phase embedded in carbon of the matrix and separated with respect to the carbon of the matrix.
Figure 8 shows the contact layer 4 according figure 7 with a friction reducing layer 27 of silver iodide arranged on the contact surface 31. According to one embodiment, the friction reducing layer of silver iodide could instead comprise another halogenide, such as a silver chloride or silver bromide.Figure 8 shows the contact layer 4 according to figure 7 with a friction reducing layer 27 of silver iodide arranged on the contact surface 31. According to one embodiment, the friction reducing layer of silver iodide could instead comprise another halide, such as a silver chloride or silver bromide.
For coating the contact surface with the silver halogenide, a number of possible coating methods are available. Among these may be mentioned electrolytic coating, evaporation or dipping the contact surface into a solution comprising at least one of the following ions: iodide, chloride, or bromide. 10 15 20 25 In a particularly preferred exemplary embodiment, the whole of or parts of the contact surfaces is coated electrolytic directly on the contact-layer of the silver-alloyed MAX- phase-material, or the silver-alloyed nanocomposite, The silver halogenide is preferably silver iodide that is formed by a spontaneous reaction between silver and iodide by exposing the contact layer, at which silver has segregated, to 12- vapor. Thereby a simple and inexpensive deposition process of silver iodide is provided.For coating the contact surface with the silver halide, a number of possible coating methods are available. Among these may be mentioned electrolytic coating, evaporation or dipping the contact surface into a solution comprising at least one of the following ions: iodide, chloride, or bromide. 10 15 20 25 In a particularly preferred exemplary embodiment, the whole of or parts of the contact surfaces is coated electrolytically directly on the contact-layer of the silver-alloyed MAX-phase-material, or the silver-alloyed nanocomposite, The silver halide is preferably silver iodide that is formed by a spontaneous reaction between silver and iodide by exposing the contact layer, at which silver has segregated, to 12- vapor. Thereby a simple and inexpensive deposition process of silver iodide is provided.
In addition to the examples of contact devices described above, several types of contact devices are available in Which it is advantageous to coat the whole of, or parts of, the contact surface of the contact element with a contact layer of a silver-alloyed MAX-phase- material, or a silver-alloyed nanocomposite, and having a friction reducing layer of silver iodide arranged thereon. An example of such a contact device is a contact device in which a first contact element, for example a resilient sleeve with an essentially rectangular cross section, in contacted state is supplied with a second contact element, for example a flat pin.In addition to the examples of contact devices described above, several types of contact devices are available in Which it is advantageous to coat the whole of, or parts of, the contact surface of the contact element with a contact layer of a silver-alloyed MAX -phase- material, or a silver-alloyed nanocomposite, and having a friction reducing layer of silver iodide arranged thereon. An example of such a contact device is a contact device in which a first contact element, for example a resilient sleeve with an essentially rectangular cross section, in contacted state is supplied with a second contact element, for example a fl at pin.
Another example of a type of contact is a contact device with a first contact element in the form of a resilient cylindrical sleeve which, in contacted state, is applied to a second contact element in the form of a solid cylindrical pin or an inner sleeve, whereby the resilient force of the sleeve causes it to bear, in clamped state, with its contact surface against the contact surface of the pin. This last type of contact also comprises sleeves with a plurality of fingers adapted to form a cylindrical sleeve. When a pin or an inner sleeve is applied to the sleeve, the fingers will bear, in clamped state, against a contact surface on the sleeve or the pin.Another example of a type of contact is a contact device with a first contact element in the form of a resilient cylindrical sleeve which, in contacted state, is applied to a second contact element in the form of a solid cylindrical pin or an inner sleeve, whereby the resilient force of the sleeve causes it to bear, in clamped state, with its contact surface against the contact surface of the pin. This last type of contact also comprises sleeves with a plurality of fingers adapted to form a cylindrical sleeve. When a pin or an inner sleeve is applied to the sleeve, the fingers will bear, in clamped state, against a contact surface on the sleeve or the pin.
To further improve the friction, the mechanical, thermal and electrical properties of the friction-reducing layer, it is possible to dope the friction-reducing layer 27 with one or more substances, for example various metals. The quantity of dopants should not exceed 20 per cent by Weight of the total weight of the friction-reducing layer.To further improve the friction, the mechanical, thermal and electrical properties of the friction-reducing layer, it is possible to dope the friction-reducing layer 27 with one or more substances, for example various metals. The quantity of dopants should not exceed 20 per cent by Weight of the total weight of the friction-reducing layer.
Claims (14)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE1100035A SE1100035A1 (en) | 2011-01-17 | 2011-01-17 | Electrical contact element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE1100035A SE1100035A1 (en) | 2011-01-17 | 2011-01-17 | Electrical contact element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| SE1100035A1 true SE1100035A1 (en) | 2011-01-31 |
Family
ID=43535822
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| SE1100035A SE1100035A1 (en) | 2011-01-17 | 2011-01-17 | Electrical contact element |
Country Status (1)
| Country | Link |
|---|---|
| SE (1) | SE1100035A1 (en) |
-
2011
- 2011-01-17 SE SE1100035A patent/SE1100035A1/en not_active Application Discontinuation
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