WO2016011908A1 - 一种耐电弧烧蚀的钨合金开关触点及其制备方法 - Google Patents

一种耐电弧烧蚀的钨合金开关触点及其制备方法 Download PDF

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WO2016011908A1
WO2016011908A1 PCT/CN2015/084164 CN2015084164W WO2016011908A1 WO 2016011908 A1 WO2016011908 A1 WO 2016011908A1 CN 2015084164 W CN2015084164 W CN 2015084164W WO 2016011908 A1 WO2016011908 A1 WO 2016011908A1
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Prior art keywords
layer
rubber
metal
nickel
alloy
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PCT/CN2015/084164
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English (en)
French (fr)
Inventor
韩辉升
王振兴
丁阳
张红梅
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南通万德科技有限公司
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Priority to US15/318,144 priority Critical patent/US10079119B2/en
Publication of WO2016011908A1 publication Critical patent/WO2016011908A1/zh

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    • 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
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/1601—Process or apparatus
    • C23C18/1633—Process of electroless plating
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/1601—Process or apparatus
    • C23C18/1633—Process of electroless plating
    • C23C18/1689—After-treatment
    • C23C18/1692—Heat-treatment
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/18—Pretreatment of the material to be coated
    • C23C18/1803—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces
    • C23C18/1806—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces by mechanical pretreatment, e.g. grinding, sanding
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/18—Pretreatment of the material to be coated
    • C23C18/1803—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces
    • C23C18/1824—Pretreatment of the material to be coated of metallic material surfaces or of a non-specific material surfaces by chemical pretreatment
    • C23C18/1837—Multistep pretreatment
    • C23C18/1844—Multistep pretreatment with use of organic or inorganic compounds other than metals, first
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/31—Coating with metals
    • C23C18/32—Coating with nickel, cobalt or mixtures thereof with phosphorus or boron
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/48—Coating with alloys
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/48—Coating with alloys
    • C23C18/50—Coating with alloys with alloys based on iron, cobalt or nickel
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/52—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating using reducing agents for coating with metallic material not provided for in a single one of groups C23C18/32 - C23C18/50
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/12—Electroplating: Baths therefor from solutions of nickel or cobalt
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/56—Electroplating: Baths therefor from solutions of alloys
    • C25D3/562—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of iron or nickel or cobalt
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D7/00—Electroplating characterised by the article coated
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D7/00—Electroplating characterised by the article coated
    • C25D7/005—Jewels; Clockworks; Coins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
    • H01H11/04—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts
    • H01H11/041—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts by bonding of a contact marking face to a contact body portion
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
    • H01H11/04—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts
    • H01H11/041—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts by bonding of a contact marking face to a contact body portion
    • H01H11/042—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts by bonding of a contact marking face to a contact body portion by mechanical deformation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
    • H01H11/04—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts
    • H01H11/06—Fixing of contacts to carrier ; Fixing of contacts to insulating carrier
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
    • H01H11/04—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts
    • H01H11/041—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts by bonding of a contact marking face to a contact body portion
    • H01H2011/046—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts by bonding of a contact marking face to a contact body portion by plating
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H11/00—Apparatus or processes specially adapted for the manufacture of electric switches
    • H01H11/04—Apparatus or processes specially adapted for the manufacture of electric switches of switch contacts
    • H01H11/06—Fixing of contacts to carrier ; Fixing of contacts to insulating carrier
    • H01H2011/067—Fixing of contacts to carrier ; Fixing of contacts to insulating carrier by deforming, e.g. bending, folding or caulking, part of the contact or terminal which is being mounted

Definitions

  • the present invention relates to a component (i.e., an electrical contact or contact) between two conductors in a switch or circuit in an electrical or electronic product that is electrically contactable by mutual contact and a method of making the same.
  • a component i.e., an electrical contact or contact
  • An electrical contact or contact is an important component of a switch or two conductors that are in contact with each other to allow current to pass through, and functions to connect, carry and disconnect normal current and fault current, and its quality and service life are directly Determines the quality and service life of the entire switch or circuit. Electrical contacts or contacts are mainly used in relays, contactors, air switches, current limiting switches, motor protectors, micro switches, instrumentation, computer keyboards, handhelds, household appliances, automotive appliances (window switches, rearview mirrors). Switch, light switch, starter motor and other load switches), leakage protection switch, etc.
  • the switching components are often a combination of a printed circuit board (PCB) with contacts and rubber buttons with contacts.
  • the circular contacts on the PCB are divided into two non-conducting halves by a straight line or curve (such as an S-curve, an M-curve).
  • the contacts on the buttons are circular without splitting.
  • a circuit on the PCB can be turned on by making a face-to-face contact with a circular contact on the PCB with a circular contact of the same diameter on the button.
  • the contact material on the button is conductive rubber or metal.
  • the contact resistance is large, and the conductive rubber contact is not suitable for the PCB circuit with a large on-current (for example, a current greater than 50 mA).
  • the metal contacts are in contact with the PCB contacts, the contact resistance is small, and the metal contacts can be used for both the PCB circuit with a small current and the PCB circuit with a large current.
  • metal contacts have problems such as chemical corrosion resistance, arc erosion resistance, and high manufacturing cost, which limits their application.
  • switching elements In the atmosphere, switching elements often generate sparks or arcs when switching on or breaking circuits.
  • the presence of a switching arc phenomenon will cause oxidation and ablation of the contacts, and may carbonize the organic matter in the air to generate carbon deposits, causing the contact resistance of the switch to gradually increase or even break.
  • Patent Document No. 201220499100.X discloses "a three-layer composite electrical contact" which is coated with a layer of silver on the contact surface of the copper-based contact body to make the contact have better electrical conductivity. And it is more economical than using silver completely.
  • silver has poor atmospheric corrosion resistance and poor salt spray resistance.
  • Silver easily reacts with hydrogen sulfide (H 2 S) in the atmosphere to form black silver sulfide.
  • H 2 S hydrogen sulfide
  • Silver is used as a point contact, and although the initial surface resistance is small, its service life in the atmosphere is also limited.
  • the cost of silver plating is lower than that of gold, silver is also one of the precious metals.
  • Patent Document No. 200580045811.2 discloses a "flat primary battery with gold-plated end contacts" which can be used, for example, in a digital camera.
  • the battery can have an anode comprising lithium and a low resistance contact.
  • the anode and cathode may be in the form of a spirally crimped sheet with a separator therebetween.
  • the external positive and negative contacts are plated with gold to improve contact resistance.
  • the electrical resistance of the invention is small, but since the melting point of gold is less than that of refractory metals such as tungsten and molybdenum, the spark resistance of the voltage withstand voltage is not good. In addition, the high price of gold also limits the range of applications of the electrical contacts.
  • the patent document with the patent number 201020143455.6 discloses a "nickel-plated tungsten contact", which belongs to the technical field of basic electrical components, and aims to solve the problem that the existing tungsten contact is easily oxidized and affects the electrical conductivity.
  • the existing tungsten contacts are mainly made of rivet type studs and tungsten sheets which are welded by pure copper.
  • the outer surface of the tungsten contact welded with the seat pin and the tungsten piece is covered with a nickel-plated layer to form a nickel-plated tungsten contact.
  • the utility model has the advantages of simple and practical structure, stable electrical conductivity and durability, and is suitable for electric appliances such as automobiles, motorcycles and electric horns.
  • the patent's contacts use a tungsten sheet with a nickel-plated layer, but nickel has low arc-ablative resistance and is not suitable for harsher applications where the operating current or voltage is large.
  • nickel is used as a switch contact to contact and disconnect (switch on and off) the gold-plated contacts of the PCB.
  • the contact resistance of the switch is about 4,000 times. Significantly elevated, even making the circuit completely open.
  • U.S. Patent 4,019,910 discloses the preparation of an electroless plating bath of a multi-metal nickel alloy.
  • the nickel alloy contains, in addition to boron or phosphorus, one or more metals such as tin, tungsten, molybdenum or copper.
  • the electroless plating solution contains an ester complex obtained by reacting a mineral acid with a polybasic acid or a polyhydric alcohol, such as a diboron ester of glucoheptonic acid, a tungstate or a molybdate.
  • the nickel alloy is mainly composed of nickel, and the nickel content is usually in the range of about 60% to about 95% by weight.
  • the alloy has excellent mechanical properties and corrosion resistance, some of which are non-magnetic or non-ferromagnetic, such as phosphorus-containing nickel alloys, particularly nickel-phosphorus-tin-copper alloys.
  • the multi-metal nickel alloy disclosed in the invention contains a relatively large amount of boron or phosphorus, as used as a contact material, and the presence of a relatively large amount of boron or phosphorus will affect the initial resistance of the contact.
  • nickel alloys with a high nickel content, nickel content (such as nickel-copper alloy or monel, nickel-chromium alloy, etc.), nickel-containing stainless steel, or nickel obtained by electroless plating are the main constituents of nickel alloys. As the contacts of the switch, they have poor arc resistance and low switching life.
  • U.S. Patent Application No. 20090088511 discloses an electroless plating solution for selectively forming a cobalt-based alloy protective film on a bare copper wire.
  • the electroless plating bath contains cobalt ions and another metal ion (tungsten and/or molybdenum), a chelating agent, a reducing agent, a specific surfactant, and a tetraalkylammonium hydroxide.
  • tungsten and/or molybdenum tungsten and/or molybdenum
  • a chelating agent such as a palladium layer
  • a specific surfactant such as a specific surfactant
  • a tetraalkylammonium hydroxide such as a palladium layer
  • the protective film has the ability to prevent diffusion and prevent electromigration.
  • this protective film is relatively hard and brittle due to its high cobalt content.
  • the surface resistance increases due to the cobalt-based alloy easily generating cobalt oxide
  • U.S. Patent No. 6,821,324 describes an aqueous plating bath for cobalt tungsten phosphorous chemical deposition containing cobalt hexahydrate, from tungsten trioxide (WO 3 ) or phosphotungstic acid [H 3 P (W 3 O 10) 4 ]
  • tungsten trioxide WO 3
  • phosphotungstic acid H 3 P (W 3 O 10) 4
  • a soluble tungsten ion source, and a phosphorus-containing reducing agent which does not contain an alkali metal ion and an alkaline earth metal ion, and the resulting deposited film contains no oxygen and has a low electrical resistivity.
  • This deposited film can be used in capping or barrier layers in semiconductor chips, VLSI products, jewelry, nuts and screws, magnetic materials, wings, advanced materials and automotive parts to prevent inter-layer metal diffusion and migrate.
  • the plating solution described in the invention has a small selection of raw materials, and since the plating solution does not contain alkali metal ions and alkaline earth metal ions, the concentration of tungsten ions in the plating solution is low (especially when tungsten trioxide is used as a raw material).
  • the tungsten content in the formed cobalt-tungsten-phosphorus deposited film is difficult to adjust, and it is difficult to obtain a deposited film having a high tungsten content.
  • the bath described in the present invention can be deposited on substrates such as silicon, silicon dioxide, jewelry, magnetic materials, and metals, and deposition is not selective to the substrate.
  • the temperature of the switching arc can reach 6000 ° C, and in the presence of oxygen, when heated to above 300 ° C, cobalt is oxidized to form CoO or Co 3 O 4 , alloy with cobalt as the main component, arc ablation resistance Poor, not suitable as a contact material, so there are few cobalt alloy electrical contacts or contacts in the industry.
  • U.S. Patent No. 6,679,132 describes the formation of a cobalt-tungsten alloy from a bath containing no alkali metal, in which no tetramethylammonium hydroxide is used, and no catalyst is used before depositing the cobalt-tungsten metal alloy onto the substrate.
  • a substrate such as a palladium catalyst pretreats a deposited layer of a cobalt-tungsten alloy using the plating solution.
  • the cobalt-tungsten alloy contains a large amount of cobalt and is not resistant to switching arc ablation. The alloy also does not relate to how to perform selective chemical deposition.
  • the invention of the patent application No. 201110193369.5 provides a "ply-faced metal-rubber composite conductive particle" which is formed by bonding a metal surface layer to a rubber substrate or by cutting after bonding.
  • the metal surface layer is a pockmark having pits, bumps or both; the pits or bumps are on the outer surface, the inner surface or both surfaces of the metal surface layer.
  • the depth of the pit is smaller than the thickness of the metal surface layer, and the height of the bump is not less than one tenth of the thickness of the metal surface layer.
  • the metal surface layer is made of metal or alloy, the outer surface can be plated with gold, silver, copper or nickel; the rubber substrate is silicone rubber or urethane rubber; the metal surface layer and the rubber substrate can have a bonding layer, and the bonding layer is The heat vulcanized adhesive, primer or the same material as the rubber matrix.
  • the inner surface of the metal surface layer may be coated with an auxiliary agent such as a coupling agent.
  • the metal surface layer of the present invention has high strength, stable electrical conductivity, high strength of the adhesive layer, and sufficient rubber base.
  • the invention does not propose a solution to solve the problem of arc erosion resistance of conductive particles.
  • the invention also does not teach a specific method of how to obtain one or more layers on the outer surface of the metal facing.
  • the noble metal such as gold-plated silver on the surface of the invention has a large surface area, a large amount of precious metal, and a high cost.
  • tungsten has the highest melting point of various pure metals, which is 3410 ° C.
  • the vapor pressure of tungsten is very low and the evaporation rate is also small.
  • the chemical properties of tungsten are very stable. They do not react with air and water at normal temperature. When not heated, any concentration of hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid and aqua regia do not work for tungsten.
  • the alkaline solution does not work for tungsten.
  • Tungsten is also a material with relatively low electrical resistivity and good electrical conductivity.
  • tungsten has a higher resistivity than silver, copper, gold, aluminum, and molybdenum, but is smaller than zinc, nickel, cadmium, palladium, iron, platinum, tin, lead, antimony, titanium, and mercury. Point material helps to reduce the contact resistance of the contacts. However, the hardness of tungsten or tungsten alloy is very high.
  • the present invention will disclose an arc-resistant ablation tungsten alloy contact and a preparation method thereof.
  • the contact may be thermally vulcanized and thermally vulcanized with a rubber to form an arc-resistant ablation.
  • the rubber button of the contact is not limited to any one of the above-resistant ablation tungsten alloy contact and a preparation method thereof.
  • the first object of the invention is to overcome the drawbacks of conventional gold-plated, silver-based or silver-plated switch contacts with high cost and low arc erosion resistance, or to overcome copper-based, tin-based, nickel-based or stainless steel contacts, although the cost is relatively high. Low but poor resistance to arc ablation, The short-lived shortcoming provides a tungsten alloy switch contact with low manufacturing cost, high on-current, and arc ablation resistance.
  • the invention provides an arc-resistant ablation tungsten alloy switch contact, wherein the switch contact is a layered composite body having a three-layer structure, and the first layer is a hydrophobic rubber layer of 0.1-10 mm thick.
  • the second layer is a 0.01-2.0 mm thick metal foil layer
  • the third layer is a 2 ⁇ 10 -5 -0.02 mm thick tungsten alloy plating layer; wherein the third layer tungsten alloy plating layer is a composite of the first layer and the second layer
  • the body is immersed in an electroless plating solution, and a tungsten alloy is deposited on the surface of the second layer in the composite of the first layer and the second layer by chemical deposition, and the tungsten alloy plating layer contains a weight ratio of 30% or more.
  • the tungsten element contains an excessive metal element of iron, cobalt, nickel, copper or manganese in a weight ratio of 0-70%, or a main group element such as tin, antimony, lead, antimony or the like
  • the ions of the transition metal element such as nickel, cobalt, copper, manganese, etc. are added to the plating solution of the tungsten alloy in order to make the plating layer adhere to the metal substrate firmly, and to accelerate the rate of chemical deposition.
  • Ions of elements such as tin, antimony, lead or antimony may also be added to the plating solution to achieve specific properties of the coating. For example, adding a small amount of stannous ions to the plating solution, or simultaneously adding stannous ions, strontium ions, and lead ions, can reduce the hardness of the plating layer.
  • a small amount of phosphorus may also be deposited in the coating due to the use of a phosphorus or boron containing reducing agent.
  • the reason for using the tungsten alloy coating as the outermost layer is that the metal tungsten is chemically stable in the atmosphere, is a high melting point metal, has a very low vapor pressure, has good arc ablation resistance, and has a conductivity higher than that of most metals. Both are high. Therefore, such a contact can pass or withstand a larger current, and the contact life is longer.
  • the more hydrophobic the rubber material used the more advantageous it is for the tungsten alloy to be deposited on the metal surface of the rubber metal layered composite used in the present invention without depositing on the surface of the rubber material.
  • a hydrophilic rubber, a rubber material containing a surfactant or an antistatic agent, and a rubber material containing a large amount of a hydrophilic or water-absorptive filler are not suitable for use in the present invention. If these rubber materials are used, a tungsten alloy plating layer will also be deposited on these rubber materials during electroless plating.
  • the hydrophobic rubber layer is caused by a low content of a carboxyl group, a hydroxyl group, a carbonyl group, an amino group, an amide group, a nitrile group, a nitro group, a halogen group, a thiol group, a sulfonate group and a benzenesulfonate group in the rubber molecular chain, thereby making the rubber
  • the surface of the rubber material having a water contact angle greater than 65°; or the hydrophobic rubber layer is due to the rubber containing no or a small amount of hydrophilic filler or additive, so that the water contact angle of the rubber surface is greater than 65 °
  • the composition of the rubber material is caused by a low content of a carboxyl group, a hydroxyl group, a carbonyl group, an amino group, an amide group, a nitrile group, a nitro group, a halogen group, a thiol group, a sulfon
  • the hydrophobic rubber layer is prepared from a non-polar or weakly polar rubber; preference is given to ethylene propylene diene monomer, methyl vinyl silicone rubber or methyl vinyl phenyl silicone rubber.
  • EPDM rubber, methyl vinyl silicone rubber and methyl vinyl phenyl silicone rubber are non-polar rubbers, which are highly hydrophobic, and they have good weather resistance and can maintain good elasticity in the atmosphere for a long time. Therefore, they It is a preferred material for the hydrophobic rubber layer.
  • the hydrophobic rubber in the hydrophobic rubber layer has a repulsive ability to water, and water cannot be spread on the surface of the hydrophobic rubber.
  • the higher the hydrophobicity of the rubber material in the composite of the first layer of the hydrophobic rubber layer and the second layer of the metal foil the better.
  • the water contact angle of the rubber substrate needs to be greater than 65°.
  • selective chemical deposition refers to a tungsten alloy plating layer which is selectively deposited on a metal material without being deposited on a rubber material.
  • the carboxyl group, hydroxyl group, carbonyl group, amino group, amide group, nitrile group, nitro group, halo group, sulfhydryl group, sulfonate group and benzenesulfonate on the rubber molecular chain will increase the polarity and hydrophilicity of the rubber.
  • carboxyl, hydroxyl, sulfonate and benzenesulfonate will greatly increase the polarity and hydrophilicity of the rubber. If a hydrophilic polyurethane rubber is used in the rubber-metal composite, chemical deposition can occur on both the metal surface and the rubber surface.
  • the rubber material has a deposited layer of tungsten alloy, it will not only waste the electroless plating solution, but also be disadvantageous to the thermal vulcanization bonding or thermoplastic bonding of the rubber material with other rubber materials, and the thermal vulcanization bonding or thermoplastic bonding. It is required for subsequent processing.
  • the first layer of hydrophobic rubber layer is present for the purpose of preparing a first layer of hydrophobic rubber layer and other rubbers for thermal vulcanization or thermoplastic bonding to produce a rubber button comprising contacts.
  • the rubber substrate it is necessary to limit the content of these polar groups in the rubber substrate to obtain a highly selective tungsten alloy chemical deposition. In order to obtain the most selective chemical deposition, these groups cannot be contained in the rubber substrate.
  • the rubber body or surface contains no or a small amount of hydrophilic fillers, additives or surfactants, which is also beneficial for selective chemical deposition.
  • EPDM rubber methyl vinyl silicone rubber, methyl vinyl silicone rubber rubber is a non-polar or weakly polar, relatively hydrophobic rubber material suitable for lamination with metal foil. Complex. When electroless plating is performed using the aforementioned electroless plating solution, chemical deposition does not occur on the rubber layer.
  • the metal foil layer of the second layer is a metal sheet having bumps or pits, a metal sheet having convex lines or concave lines, a metal sheet having convex or concave surfaces, and an area of less than 1 mm 2 Small hole metal sheet, metal mesh, metal foam or metal fiber sintered felt to make contact with the contacts on the PCB with greater pressure and better conductivity; metal materials are magnesium, aluminum, titanium, chromium, manganese, Iron, cobalt, nickel, copper, zinc, antimony, molybdenum, silver, tin, gold or an alloy containing these elements; the metal foil layer is formed by a single metal material or a layered composite of different metal materials; Metals or alloys which are stable in the atmosphere, have high electrical conductivity and are relatively inexpensive, such as stainless steel or nickel alloys, are preferred.
  • the second layer of metal foil consists of 0.01-1.0 mm thick stainless steel, copper or copper alloy, nickel or nickel alloy flakes, on one or both sides of stainless steel, copper or copper alloy, nickel or nickel alloy flakes. It is plated with a pure nickel layer or a nickel alloy layer of 0.01-10 micrometers; a nickel alloy layer on a stainless steel, copper or copper alloy, nickel or nickel alloy sheet is prepared by vacuum coating, electroplating or electroless plating.
  • Plating a pure nickel or nickel alloy layer on stainless steel, copper or copper alloy, nickel or nickel alloy flakes The bonding strength with the tungsten alloy coating prevents the tungsten alloy coating from falling off during the use of the contacts.
  • copper and copper alloy flakes should be coated with a thin layer of pure nickel or nickel alloy on both sides of the copper and copper alloy flakes prior to chemical deposition of the tungsten alloy coating to improve oxidation and chemical resistance of copper and copper alloys. Performance.
  • the stainless steel selected is ordinary stainless steel, acid-resistant steel, or added with molybdenum to improve the atmospheric corrosion resistance, especially for special corrosion resistant stainless steel containing chloride atmosphere.
  • the thickness of the metal foil should not be too thin. If the thickness of the metal foil of the second layer is less than 0.01 mm, the tungsten alloy plating layer of the third layer may not be well supported, and is easily broken during processing before, during or after the compounding with the rubber. If the metal foil of the second layer is too thick, the overall hardness of the contact is increased while the metal material is wasted. Therefore, the thickness of the metal foil should not be greater than 1.0 mm.
  • the first layer of the hydrophobic rubber layer and the second layer of the metal foil are formed into a layered composite in advance for the convenience of applying the layered composite as a contact to prepare a rubber button.
  • the hydrophobic rubber on the layered composite can be directly vulcanized or thermoplastically bonded to other rubbers to form a rubber button. If the metal foil without the rubber layer and the other rubber are subjected to thermal vulcanization bonding and hot vulcanization molding, or thermoplastic bonding and thermoplastic molding to form a rubber button, gelation, poor adhesion, and the like may occur during the molding process.
  • the so-called overflow phenomenon means that during the molding process, the rubber overflows to the front side of the contact, thereby affecting the electrical conductivity of the contact. There is an overflow on the contacts, which is unacceptable for the quality of the contacts.
  • a second object of the invention is to provide a method of preparing the above-described switch that is resistant to arc ablation.
  • a second technical solution a method for preparing an arc-resistant ablation switch contact, comprising the following steps:
  • the metal foil is a stainless steel, copper or copper alloy, nickel or nickel alloy sheet of 0.01 mm to 1.0 mm thick; the metal foil is degreased and cleaned with a cleaning agent and an organic solvent; or by sandblasting Grinding the surface of the metal sheet by mechanical roughening; or chemical etching to treat pits or bumps having a diameter of less than 1 mm; or plating one or both sides of the metal sheet by plating or electroless plating to 0.1 ⁇ m To a pure nickel layer or a nickel alloy layer of 10 micrometers; then, the obtained metal foil is degreased and washed with a cleaning agent and an organic solvent;
  • Hydrophobic rubber is formed by thermal vulcanization bonding and thermal vulcanization, and bonded to a metal foil coated with a primer or an adhesion promoter to form a layered composite.
  • the purpose of cleaning with 5% hydrochloric acid is to remove the oxide on the surface of a part of the metal substrate, activate the surface of the metal substrate, and enhance the bonding strength between the metal substrate and the tungsten alloy plating layer. It is also feasible to use other cleaning and acid activation methods.
  • tungsten alloy plating layer immersing the above-mentioned cylinder or object in an electroless plating solution containing a soluble tungsten compound, stirring, and forming a tungsten alloy plating layer on a metal surface of a cylinder or an object by electroless plating; or Putting the above cylinder into a drum of an electroless plating solution containing a soluble tungsten compound, rotating the drum, and forming a tungsten alloy plating layer on the metal surface of the cylinder by electroless plating;
  • the bath contains 40-125 g/L of soluble tungsten compound, 0-60 g/L of soluble transition metal iron, nickel, cobalt, copper or manganese compound or any combination of these compounds, 0-30 g/L of soluble Tin, antimony, lead or antimony compound or any combination of these compounds, 20-100 g/L reducing agent, 30-150 g/L complexing agent, 20-100 g/L pH adjusting agent, 0.1-1 g/L Stabilizer, 0.1-1 g/L surfactant, 0-50 g/L brightener or roughness modifier; other additives such as electroless plating accelerator may also be added to the plating solution.
  • the accelerator can be selected from sodium fluoride. Sodium fluoride can be used as an accelerator, and can also increase the brightness of the coating;
  • Sodium hypophosphite is preferably used as the reducing agent.
  • the temperature of the electroless plating of the tungsten alloy plating layer is 65-85 ° C for 30-300 minutes, and the pH of the plating solution is 8.0-10.0.
  • the tungsten-containing alloy plating layer is subjected to electroless plating at a temperature of 70-80 ° C for 100-200 minutes, and the pH of the plating solution is 8.5-9.0; the plating solution contains a strong base having a pH buffering capacity. a weak acid salt; the pH adjusting agent is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium acetate, ammonia water, sodium pyrophosphate, potassium pyrophosphate, and preferably uses ammonia water or sodium hydroxide solution. Adjust the pH of the bath.
  • the choice of electroless plating time is related to the performance requirements or service life requirements of the arc ablation resistance of the switch product.
  • the longer the electroless plating time the thicker the tungsten alloy coating deposited on the metal substrate. A thicker tungsten alloy coating facilitates the switching arc resistance of the contacts.
  • the time of electroless plating is not as long as possible.
  • the electroless plating time is too long, not only the production efficiency is low, but also the alkaline electroless plating solution may damage the adhesion strength between the first layer of the hydrophobic rubber layer and the second layer of the metal foil layer, and even cause the peeling Layer phenomenon.
  • the time for electroless plating of the tungsten alloy plating layer is 200 minutes.
  • the soluble tungsten compound is one or more selected from the group consisting of potassium tungstate, sodium tungstate, ammonium tungstate, ammonium dithanoate, ammonium tetratitanate, ammonium heptoxide, and ammonium octatitanate.
  • Tungsten trioxide or tungstic acid can also be used. Although tungsten trioxide or tungstic acid is insoluble in neutral water, it is soluble in alkaline water.
  • tungsten trioxide or tungstic acid When tungsten trioxide or tungstic acid is used, it is first dissolved with sodium hydroxide alkali solution or ammonia water having a pH greater than 12, and then the electroless plating solution is disposed with dissolved tungstic acid or tungsten trioxide. It is preferred to prepare an electroless plating solution by using sodium tungstate which is easily dissolved in water and has a low price.
  • the soluble transition metal iron, cobalt, nickel, copper or manganese compound is ferrous sulfate, ammonium ferrous sulfate, cobalt sulfate, cobalt chloride, cobalt nitrate, cobalt ammonium sulfate, basic cobalt carbonate, cobalt sulfamate , cobalt acetate, cobalt oxalate, nickel sulfate, nickel chloride, nickel nitrate, nickel ammonium sulfate, basic nickel carbonate, nickel sulfamate, nickel acetate, nickel hypophosphite, nickel hypophosphite, nickel hydroxide, copper sulfate, One or more of copper chloride, copper nitrate, hydrated basic copper carbonate, copper acetate, manganese sulfate or manganese chloride.
  • nickel hydroxide When using nickel hydroxide, it is first dissolved with ammonia water. We found in the tungsten plating alloy that nickel sulfate and alkali were used in the electroless plating solution. Nickel carbonate is compounded as a precursor of nickel, and the plated tungsten alloy layer can have a bright silver white color, and the obtained tungsten alloy plating layer has a low surface resistance.
  • a compound containing a soluble transition metal element other than iron, cobalt, nickel, copper or manganese, and a compound of a soluble main group element such as a tin compound, a cerium compound, a cerium compound and a lead compound may be added to the plating solution, but it should be noted that these compound pairs The effect of electroless plating on the selectivity of the deposited substrate.
  • soluble lead compounds that are harmful to humans and the environment should be used sparingly or not.
  • silver is a commonly used element in electrical contacts or contacts, it is not recommended to add a soluble silver compound such as silver nitrate to the tungsten alloy plating solution.
  • the layered composite of the first layer of the hydrophobic rubber layer and the second layer of the metal foil layer is carried out.
  • the chemical deposition that occurs will occur not only on the metal foil layer of the second layer but also on the hydrophobic rubber layer of the first layer, so that chemical deposition is not selective to the substrate.
  • the deposition time is long enough, it is clearly visible to the naked eye that there are grayish black or silvery white deposits on the hydrophobic rubber layer and on the metal foil layer.
  • the surface of the metal foil layer and the surface of the hydrophobic rubber layer contained a large amount of silver. After the addition of silver nitrate is eliminated using the same formulation, the chemical deposition layer is formed only on the metal surface of the metal foil layer during the electroless plating.
  • the reducing agent is one or more of sodium hypophosphite, sodium borohydride, alkylamine borane, and hydrazine. If borohydride or aminoborane is used as the reducing agent, the tungsten alloy coating will contain a small amount of boron (mass fraction up to 7%). With ruthenium as a reducing agent, the content of non-metal (phosphorus or boron) in the obtained coating layer is almost zero, and the metal content can reach 99% or more. The use of sodium hypophosphite as a reducing agent has a good cost performance and its toxicity is also low.
  • the coating contains a small amount of phosphorus (mass fraction up to 15%) in addition to metal tungsten and other metal elements. Phosphorus is detrimental to the electrical conductivity of the contacts and can damage the corrosion resistance of the tungsten alloy. Therefore, it is necessary to control the phosphorus content in the tungsten alloy.
  • the phosphorus content in the coating can be controlled by controlling the concentration of sodium hypophosphite, the concentration of the complexing agent, and the pH. Controlling and controlling the phosphorus content provides a dense, non-porous tungsten alloy coating.
  • the contact resistance between the tungsten alloy coating and the tungsten alloy coating obtained by us is less than the contact resistance between 99.5% pure nickel and 99.5% pure nickel, and the obtained coating energy can be obtained. Significantly improve the resistance to switching arc of metal substrates.
  • the complexing agent is one or more of sodium citrate, ammonium citrate, sodium tartrate, sodium potassium tartrate, disodium ethylenediaminetetraacetate, and tetrasodium ethylenediaminetetraacetate.
  • the function of the complexing agent is to control the concentration of free metal ions available for reaction, improve the stability of the plating solution, prolong the life of the plating solution, and improve the quality of the plating layer.
  • Complexing agents have an effect on deposition rate, phosphorus content and corrosion resistance.
  • the pH adjuster is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogencarbonate, sodium acetate, ammonium sulfate, aqueous ammonia, sodium pyrophosphate, and potassium pyrophosphate.
  • the pH of the bath is preferably adjusted with ammonia or sodium hydroxide solution. This makes it possible to obtain a tungsten alloy coating which is stronger, more stable, and has better plating quality. The longer the electroless plating time, the thicker the tungsten alloy coating deposited on the metal substrate. A thicker tungsten alloy coating facilitates the switching arc resistance of the contacts. But the time of electroless plating is not as long as possible.
  • the electroless plating time is too long, not only the production efficiency is low, but also the alkaline electroless plating solution may be
  • the bond strength between the first layer of the hydrophobic rubber layer and the second layer of the metal foil layer is damaged, and even delamination is caused.
  • sodium hypophosphite is used as the reducing agent, the pH should not be greater than 12 because the excessively high pH causes the deposition rate to be accelerated, but the adhesion between the plating layer or the deposited layer and the metal substrate is deteriorated, so that the plating or deposition The color of the layer becomes darker and even becomes black.
  • a strong acid weak base salt or a strong base weak acid salt may be added to the plating solution as a pH buffer for the plating solution.
  • the stabilizer is potassium iodide, potassium iodate, benzotriazole, 4,5-dithiooctane-1,8-disulfonate, 3- a mixture of one or more of decyl-1-propane sulfonate, sodium thiosulfate, thiourea.
  • the brightener (or surface roughness modifier) may be one or more of other commercially available electroless brighteners.
  • the stabilizer is preferably sodium thiosulfate, thiourea or a mixture of the two, so that the tungsten alloy coating has a good metallic luster at the same time.
  • the role of the stabilizer is to inhibit the autocatalytic reaction occurring during the electroless plating process to stabilize the plating solution, prevent the intense autocatalytic reaction, and prevent the formation of a large amount of phosphorus-containing ferrous metal powder.
  • the stabilizer is a poisoning agent for electroless plating, that is, a countercatalytic reaction, so it cannot be excessively used, and it is necessary to control its amount in the plating solution so as not to affect the electroless plating efficiency.
  • the plating solution used for the electroless plating further contains 0.1-1 g/L of a surfactant;
  • the surfactant is: dodecylbenzenesulfonate, lauryl sulfate,
  • the addition of some surfactants helps the gas on the surface of the plated material to overflow, reduces the porosity of the coating, and densifies the coating, thereby increasing the arc resistance of the coating.
  • the plating solution used for the electroless plating may further contain a brightener or a roughness modifier of up to 50 g/L;
  • the brightener or roughness modifier is formaldehyde, acetaldehyde, ⁇ -naphthalene Phenol, 2-methyl aldehyde aniline, benzylideneacetone, cumyl aldehyde, benzophenone, chlorobenzaldehyde, pingpingjia, xifen base, butyne diol, propynyl alcohol, 1-diethylaminopropyl 2-yne, ethoxylated propynyl alcohol, sulfonyl benzoimide, sodium sulfonylimide, sodium vinyl sulfonate, sodium propyne sulfonate, pyridine-2-hydroxypropane sulfonic acid Salts, alkylphenol ethoxylates or commercially available electroplating or electroless plating
  • a composite of a hydrophobic rubber layer and a metal foil layer is used, and electroless plating is performed using the above plating solution to deposit a tungsten alloy plating layer on the surface of the metal.
  • XRF X-ray fluorescence spectrometer
  • the present invention selectively coats a tungsten-containing alloy by electroless plating on a layered composite of a hydrophobic rubber layer and a metal foil, which can effectively improve the electrical conductivity of the metal foil and the resistance to switching arc burning. Corrosion performance.
  • Contacts made of a tungsten alloy layer made of a stainless steel sheet (such as SS304 stainless steel sheet), a nickel sheet (such as N6 nickel sheet), a nickel alloy sheet (such as NCu30 nickel-copper sheet), and a printed circuit board (PCB)
  • the contact between the gold-plated contacts and the contact resistance between the contacts is less than the contact resistance between the similar contacts without the tungsten alloy and the gold-plated contacts on the printed circuit board (PCB), and has good conduction performance.
  • This tungsten-plated contact has better resistance to arc ablation by passing or withstanding higher currents than switch contacts coated with gold, platinum or silver. Moreover, the price of metallic tungsten is much lower than that of gold, platinum or silver.
  • the tungsten alloy contact of the present invention contains a hydrophobic rubber layer and has characteristics of being easily vulcanized and bonded with rubber to form a rubber button product containing a contact.
  • the product of the invention is suitable for use in various high-grade places, and is particularly suitable for making switch contacts that require large current (current greater than 50 mA) to pass through the button in the electrical and electronic equipment such as automobiles, power tools, game machines and the like.
  • 1 is a schematic cross-sectional view of the present invention; in the figure: 1, a rubber layer; 2, a metal foil layer; 3, a tungsten alloy plating layer;
  • Figure 2 is a process flow diagram of the preparation process of the present invention.
  • composition of plating solution sodium tungstate 100g/L, sodium hypophosphite 35g/L, sodium citrate 50g/L, sodium potassium tartrate 30g/L, ammonium sulfate 30g/L, sodium pyrophosphate 24g/L, potassium iodate 40mg /L, sodium thiosulfate 32 mg / L, sodium lauryl sulfate 1 g / L.
  • Amount of ammonia water is added to maintain the pH of the bath between 8.5 and 9.5.
  • a metal foil layer 2 was formed by using a zinc-copper sheet having a thickness of 0.1 mm, an HV hardness of 120 to 180, and a copper content of about 55% as a metal substrate.
  • the reason for choosing zinc white copper is that zinc white copper has excellent comprehensive mechanical properties, excellent corrosion resistance, good hot and cold processing formability, and is suitable for manufacturing various elastic components.
  • the smooth zinc-copper sheet was mechanically rolled into a fine corrugated sheet having a corrugation peak height of 0.2 mm and a peak pitch of 0.4 mm.
  • VTPS vinyl tri-tert-peroxysilane
  • DCP dicumyl peroxide
  • the fine corrugated zinc white copper sheet coated with a nickel layer and the above-mentioned kneaded rubber were subjected to thermal vulcanization bonding and hot vulcanization molding at 165 ° C, and the vulcanization time was 10 minutes.
  • a layered composite sheet of 1.25 mm thick zinc white copper and silicone rubber was formed.
  • the cavity of the mold for producing the composite sheet is coated with Teflon on the surface of the cavity. This composite sheet was die cut into small round particles having a diameter of 5 mm.
  • the small round particles are washed with an alkaline cleaning solution for several minutes, washed with water, then immersed in 5% hydrochloric acid for 3 minutes, and finally activated in 10% dilute sulfuric acid for 1 minute, then washed with distilled water or ionized water, dried. .
  • the 500 small wafers were placed in the above 300 ml plating solution at 80 ° C, stirred, taken out after 200 minutes, rinsed with distilled water or deionized water, drained, and dried in a constant temperature oven at 70 ° C to obtain Small round grains of a tungsten alloy are plated on the metal foil layer 2.
  • the thickness and density of the tungsten-plated alloy are related to the time during which the small rounds are placed in the bath. The longer the placement time, the thicker the thickness of the tungsten alloy plating layer 3.
  • the tungsten alloy is deposited only on the surface of the stainless steel in the small round grains, and is not deposited on the surface of the rubber layer 1 in the small round particles, as shown in FIG.
  • the silicon-containing rubber layer 1 is coated with a tungsten alloy-shaped small round grain and is thermally vulcanized and bonded with a silicone rubber (the silicone rubber surface in the small round grain and the other silicone rubber are thermally vulcanized and bonded, and the side coated with the tungsten alloy) It can be used as a contact for a circuit switch in a rubber button that is in contact with a gold-plated contact of a printed circuit board (PCB).
  • PCB printed circuit board
  • the contact resistance between the grain and the gold-plated contacts of the PCB is low, and the small round grains coated with tungsten alloy have better conduction stability: small round particles and PCB made of stainless steel without tungsten alloy plating 3
  • the gold-plated contacts pass 300 mA of DC power. After about 2,000 switching cycles, the contact resistance between the small round particles and the PCB gold-plated contacts is significantly increased (by about 1 ⁇ due to arc ablation when the circuit is turned on and off). Elevated to more than 100 ⁇ , even in the case of multiple tests, non-conductivity can occur; and under the same circuit conditions, the small round particles coated with tungsten alloy and the gold-plated contacts of the PCB pass 300 mA of DC power.
  • the contact resistance between the small wafer and the gold-plated contacts of the PCB after about 10,000 switching, Still below 1 ⁇ .
  • composition of plating solution sodium tungstate 90g/L, nickel sulfate 10g/L, basic nickel carbonate 16g/L, sodium hypophosphite 25g/L, sodium citrate 50g/L, sodium potassium tartrate 30g/L, ammonium sulfate 30g / L, sodium pyrophosphate 24 g / L, potassium iodate 40 mg / L, sodium thiosulfate 32 mg / L, sodium lauryl sulfate 1 g / L, sodium sulfonimide 20 g / L.
  • Amount of ammonia water is added to maintain the pH of the bath between 8.5 and 9.5.
  • a 0.075 mm thick flat stainless steel sheet (Model 304) was subjected to alkaline degreasing and anode degreasing, then washed with tap water, then rinsed with distilled water and alcohol, and one side was rubberized.
  • - Metallic adhesive selected from Megum 3270 manufactured by Rohm and Haas Company, USA
  • a methyl vinyl silicone rubber for example, manufactured by Shin-Etsu Co., Ltd.
  • KE 951U was subjected to thermal vulcanization bonding to form a 1.0 mm thick stainless steel-silicone rubber composite sheet. This composite sheet was die cut into small round particles having a diameter of 5 mm.
  • the small round pellets were washed with an alkaline cleaning solution at 70 ° C for about 5 minutes, washed with water, then washed with 5% hydrochloric acid for 3 minutes, then washed with deionized water and filtered.
  • the small round particles coated with tungsten alloy are heat-vulcanized and bonded by silicone rubber (the silicone rubber surface in small round grains and other silicone rubber are thermally vulcanized and bonded, and the side coated with tungsten-nickel alloy In addition, it can be used as a contact for a circuit switch in a rubber button.
  • the contact is in contact with a gold-plated contact of a printed circuit board (PCB).
  • PCB printed circuit board
  • the contact resistance between the gold-plated contacts of the PCB is low, and the small round grains coated with tungsten alloy have better conduction stability: small round particles made of stainless steel without tungsten alloy plating 3 and gold-plated contacts of the PCB After passing through 300 mA of DC power, after about 2,000 times of switching, the contact resistance between the small round particles and the gold-plated contacts of the PCB is significantly increased (from about 1 ⁇ to more than 100 ⁇ due to arc ablation during switching). In the case of multiple tests, even non-conducting can occur; and under the same circuit conditions, the small round particles coated with tungsten alloy and the gold-plated contacts of the PCB pass 500 mA of DC power, after switching about 20,000 times. The contact resistance between this small wafer and the gold-plated contacts of the PCB is still 1 ⁇ Next.
  • Example 2 Replace the stainless steel sheet in Example 2 with a 400 mesh stainless steel plain mesh (stainless steel model 304), using the process of 2 and the electroless plating solution, and the resulting contacts also have lower contact resistance and better Resistance to arc ablation.
  • the 400 mesh stainless steel mesh has a small mesh opening, and the silicone rubber does not penetrate the mesh of the stainless steel mesh when molded with the silicone rubber. If a stainless steel mesh with a small mesh size, such as a stainless steel mesh of 80 mesh or less, is used, a process problem in which the silicone rubber penetrates the stainless steel mesh is generated during molding. Therefore, it is necessary to use a stainless steel mesh having an increased mesh size to prepare a contact having a tungsten alloy plating layer 3.

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Abstract

本发明公开了一种耐电弧烧蚀的钨合金开关触点及其制备方法，触点部件具有三层结构，第一层为疏水性橡胶层，第二层为金属薄片层，第三层为钨合金的化学沉积层。本化学沉积所采用的镀液中含有25-125g/L的可溶性钨化合物、0-60g/L的可溶性的过渡金属铁、镍、钴、铜或锰的化合物、0-30g/L的可溶性的锡、锑、铅或铋化合物。当疏水性橡胶层和金属薄片层的层状复合体用此镀液进行化学镀时，钨合金镀层选择性地沉积在金属表面上，在疏水性橡胶表面根本上不发生钨合金的化学沉积。本发明所制备的开关触点，具有良好的金属色泽，较低的接触电阻，较高的耐开关电弧烧蚀性能和较长的使用寿命，并且适合与橡胶进行热硫化粘合和成型。

Description

一种耐电弧烧蚀的钨合金开关触点及其制备方法 技术领域
本发明具体涉及一种电力或电子产品中的开关或电路中两个导体之间可通过相互接触从而可供电流通过的零部件(也就是电触头或触点)及其制备方法。
背景技术
电触头或触点是开关或电路中两个导体之间通过相互接触从而可供电流通过的重要零部件，承担接通、承载和分断正常电流和故障电流的功能，其质量和使用寿命直接决定着整个开关或电路的质量和使用寿命。电触头或触点主要应用于继电器、接触器、空气开关、限流开关、电机保护器、微型开关、仪器仪表、电脑键盘、手持机、家用电器、汽车电器(车窗开关、后视镜开关、灯开关、起动电机等负荷开关)、漏电保护开关等。电触点或触点的制备材料很多，主要有银、银镍、银氧化铜、银氧化镉、银氧化锡、银氧化锡氧化铟、银氧化锌、紫铜、黄铜、磷铜、青铜、锡铜、铍铜、铜镍、锌白铜、不锈钢等。
在汽车电器、家用电器、电脑键盘和手持机等设备中，其开关部件常常是设有触点的印刷电路板(PCB)和设有触点的橡胶按键的组合。PCB上的圆形触点，被一条直线或曲线(如S型曲线、M型曲线)分割成不导通的两半。按键上的触点是不用分割的圆形。用按键上的一个相同直径的圆形触点，与PCB上的一个圆形触点作面对面的接触，就可以接通PCB上的一个电路。按键上的触点材料，是导电橡胶或金属。导电橡胶触点与PCB触点相接触时的接触电阻较大，导电橡胶触点不适用于接通电流较大(例如电流大于50毫安)的PCB电路。金属触点与PCB触点相接触时的接触电阻较小，金属触点既可以用于接通电流较小的PCB电路，也可以用于接通电流较大的PCB电路。但目前金属触点存在耐化学品腐蚀、耐电弧烧蚀性能不理想、制作成本高从而使其应用受到限制等问题。
在大气中，开关元件在接通电路或分断电路时常产生电火花或电弧。开关电弧现象的存在，将导致触点氧化和烧蚀，并且可能使空气中的有机质碳化从而产生积碳，使开关的接触电阻逐渐增大甚至断路。
申请专利号为201220499100.X的专利文件公开了“一种三层复合电触点”，该触点是在铜基触点本体的接触面上镀一层银，使得触点的导电性能更好，且比完全采用银制成要节省生产成本。虽然银的导电性和传热性在所有的金属中都是最高的，但银的耐大气腐蚀性能较差、耐盐雾性能较差。银易与大气中的硫化氢(H2S)反应生成黑色的硫化银。银作为点触点使用，虽然初始表面电阻小，但其在大气中的使用寿命也受到限制。虽然镀银的成本比黄金低，但银也是贵金属之一。另外，在这样的电触点中，没有橡胶层，因此，这种电触点不适于与橡胶进行热硫化粘合和热硫化成型从而制成含有电触点的橡胶按键。只有含有橡胶层的触点，或者全部由导电橡胶构成的触点，才可能顺利与其它橡胶进行热硫化粘合和热硫化成型从而制成含有电触点的橡胶按键，而不会在热硫化粘合和热硫化成型过程中产生溢胶、粘合不良等质量问题。
申请专利号为200580045811.2的专利文件公开了一种“具有镀金端触点的扁平一次电池”，该电池可用于例如数字照相机。该电池可具有包含锂的阳极和低电阻的触点。阳极和阴极可呈其间带有隔板的螺旋形卷曲的薄片形式。外部正负触点用金镀覆以改善接触电阻。该发明电触点的电阻虽小，但是由于黄金的熔点不及钨、钼等难熔金属，所以其耐电压产生的火花性能欠佳。另外，黄金高昂的价格也限制了该电触点的应用范围。
申请专利号为201020143455.6的专利文件公开了一种“镀镍钨触点”，属于基本电器元件技术领域，旨在解决现有的钨触点易氧化，影响导电性能的问题。在公知技术中，现有的钨触点主要是铆钉型座钉和钨片以纯铜为焊料熔焊制作成。本专利中采用在座钉和钨片焊连的钨触点外表面包罩连接镀镍层所组成为镀镍的钨触点。其结构简单实用，导电性能稳定，经久耐用，适用于汽车、摩托车、电喇叭等电器。该专利的触点采用钨片外加镀镍层，但镍的耐电弧烧蚀性能低，不宜用于工作电流或电压较大的较苛刻的场合。我们的测试表明，镍作为开关触点与PCB的镀金触点接触和分断(开和关)，在室温下，但工作电流为300毫安时，开关次数4000次左右之后，开关的接触电阻就显著升高，甚至使电路完全断路。
美国专利4019910公开了制备一种多金属的镍合金的化学镀液。该镍合金中除了含有硼或磷，还含有一种或一种以上的金属如锡、钨、钼或铜。该化学镀液中含有无机酸和多元酸或多元醇反应所得的酯复合物，如葡庚糖酸的二硼酯、钨酸酯或钼酸酯。该镍合金主要由镍组成，镍含量通常在大约60％至大约95％(重量比)的范围内。该合金有优良的机械性能和耐腐蚀性能，其中某些合金如含磷的镍合金，特别是镍-磷-锡-铜合金，具有非磁性或非铁磁性。该发明所公开的多金属的镍合金含有较大含量的硼或磷，如作为触点材料使用，较大含量的硼或磷的存在，将影响触点的初始电阻。我们的测试表明，纯镍、镍含量大的镍合金(如镍铜合金或蒙乃尔合金、镍铬合金等)、含镍的不锈钢、或用化学镀得到的镍为主要组成的镍合金，如果作为开关的触点，都具有较差的耐电弧性能和较低的开关使用寿命。
美国专利申请20090088511公开了在裸露的铜线上选择性地形成一种钴基合金保护膜的化学镀液。化学镀液中包含了钴离子和另一种金属离子(钨和/或钼)、螯合剂、还原剂、特定的表面活性剂和四烷基氢氧化铵。使用该发明所公开的镀液，不需要在化学镀之前使用一种子层(如钯层)。该保护膜具有防扩散、防电迁移的能力。但这种保护膜由于钴含量高，比较硬而脆。此外，由于在电弧作用下钴基合金很容易产生钴的氧化物而导致表面电阻上升。这种保护膜耐电弧烧蚀性能不好，不宜用来制作电触头或触点。
美国专利号为US 6821324的发明，描述了用于钴钨磷化学沉积的水性镀液含有六水氯化钴、来自三氧化钨(WO3)或磷钨酸[H3P(W3O10)4]的可溶性钨离子源，以及一种含磷的还原剂，不含碱金属离子和碱土金属离子，所得到的沉积薄膜不含氧，具有低的电阻率。这种沉积薄膜可用于半导体芯片、超大规模集成电路产品、珠宝、螺母和螺钉、磁性材料、机翼、先进材料和汽车部件等产品中的封盖层或阻挡层，以防止层间金属扩散和迁移。该发明所描述的镀液，原材料选择的种类少，由于镀液中不含碱金属离子和碱土金属离子，镀液中的钨离子 的浓度较低(特别是当三氧化钨用作原料时)，所形成的钴钨磷沉积薄膜中的钨含量难以调节，难以得到高钨含量的沉积薄膜。该发明所描述的镀液，可在硅、二氧化硅、珠宝、磁性材料和金属等基材上沉积，沉积对基材没有选择性。此外，开关电弧的温度可达6000℃，而在氧气存在的情况下，加热至300℃以上时，钴被氧化生成CoO或Co3O4，以钴作为主要成分的合金，耐电弧烧蚀性能不佳，不宜作为触点材料，所以工业上很少有钴合金电触头或触点。
美国专利号为6797312的发明，描述了用不含碱金属的镀液形成钴钨合金，在镀液中可不使用四甲基氢氧化铵，在沉积钴钨金属合金到基材上之前，不用催化剂如钯催化剂预处理基材，使用该镀液就可得到钴钨合金的沉积层。该钴钨合金中含有大量的钴元素，不耐开关电弧烧蚀。该合金该发明也没有涉及到如何进行选择性的化学沉积。
本专利权人的申请专利号为201110193369.5的发明提供了一种“麻面金属与橡胶复合导电粒”，由金属面层与橡胶基体粘合而成，或者粘合后分切而成。金属面层为麻面，具有凹坑、凸点或者两者均有；凹坑或凸点在金属面层的外表面、内表面或者两个表面均有。凹坑的深度小于金属面层厚度，凸点的高度不小于金属面层厚度的十分之一。金属面层的材质为金属或合金，外表面可镀金、银、铜或镍等；橡胶基体为硅橡胶或聚氨酯橡胶等；金属面层与橡胶基体之间可有粘接层，粘接层为热硫化胶粘剂、底涂剂或为与橡胶基体相同的材质。金属面层内表面可涂有偶联剂等助剂。本发明的金属面层强度高、导电性稳定，粘接层强度高，橡胶基体弹性足。该发明没有为解决导电粒的耐电弧烧蚀问题提出解决方案。该发明也没有提出如何在金属面层的外表面上获得一层或多层镀层的具体方法。该发明的麻面上镀金银等贵金属，由于表面积大，贵金属用量多，成本高。
众所周知，各种纯金属中以钨的熔点最高，为3410℃。钨的蒸气压很低，蒸发速度也较小。钨的化学性质很稳定，常温时不跟空气和水反应，不加热时，任何浓度的盐酸、硫酸、硝酸、氢氟酸以及王水对钨都不起作用。碱溶液对钨也不起作用。钨还是一种电阻率比较小、导电性比较好的材料。在各种纯金属中，钨的电阻率比银、铜、金、铝、钼大，但比锌、镍、镉、钯、铁、铂、锡、铅、锑、钛、汞小，作为触点材料时有利于降低触点的接触电阻。但钨或钨合金的硬度很高，以机械压制法或粉末冶金法，难以得厚度较小的钨或钨合金合金的薄片(特别是厚度小于0.05mm的钨合金薄片)，如果将较厚的钨合金的薄片，直接用于生产金属触点，不仅将增大金属触点的原材料成本，而且由于钨或钨合金合金的硬度大，进行分割或冲切加工困难。由于钨与其它金属性质的显著差异，在电子产品中，特别是在触点中，未有成熟的和广泛使用的应用技术。
本发明，将公开一种耐电弧烧蚀的钨合金触点及其制备方法，这种触点由于包含橡胶层，因而可与橡胶进行热硫化粘合和热硫化成型从而制备包含耐电弧烧蚀的触点的橡胶按键。
发明内容
第一发明目的：克服传统镀金、银基或镀银的开关触点成本较高、耐电弧烧蚀性能不太高的缺陷，或者克服铜基、锡基、镍基或不锈钢触点虽然成本较低但耐电弧烧蚀性能较差、 寿命较短的缺点，提供一种制造成本低、导通电流大、耐电弧烧蚀的钨合金开关触点。
第一技术方案：本发明提供的一种耐电弧烧蚀的钨合金开关触点，开关触点是具有三层结构的层状复合体，第一层为0.1-10mm厚的疏水性橡胶层，第二层为0.01-2.0mm厚的金属薄片层，第三层为2×10-5-0.02mm厚的钨合金镀层；其中，第三层钨合金镀层是第一层和第二层的复合体浸泡在化学镀液中，用化学沉积的方法将钨合金沉积在第一层和第二层的复合体中第二层的表面而形成的，钨合金镀层中含有重量比为30％以上的钨元素、含有重量比为0-70％的过度金属元素铁、钴、镍、铜或锰、或者主族元素锡、锑、铅、铋等。
在钨合金的镀液中加入镍、钴、铜、锰等过渡金属元素的离子，是为了使镀层与金属基材粘合牢固，并且为了加快化学沉积的速率。镀液中还可以加入锡、锑、铅或铋等元素的离子，以使镀层获得特定的性能。比如，在镀液中加入少量的亚锡离子，或者同时加入亚锡离子、锑离子和铅离子，可使镀层的硬度下降。由于使用了含磷或含硼的还原剂，少量的磷也可能沉积在镀层中。但由于镀层中磷和硼的含量高，将使镀层的初始表面电阻增大，因此，应采取控制镀液中还原剂的浓度和镀液温度等措施，来控制镀层中磷和硼的含量。
采用钨合金镀层做最外层原因在于：金属钨在大气中化学性质稳定，是高熔点金属，蒸气压极低，具有比较好的耐电弧烧蚀性能，并且，钨的电导率比大多数金属都高。因此这种触点能够通过或承受更大的电流，触点使用寿命更长。
一般来说，所用橡胶材料的疏水性越强，越有利于钨合金在本发明中所使用橡胶金属层状复合物中的金属面上沉积，而不在橡胶材料的表面上沉积。亲水性橡胶、含有表面活性剂或抗静电剂的橡胶材料、含有大量亲水性或吸水性填料的橡胶材料，不宜在本发明中使用。如果使用这些橡胶材料，在进行化学镀时，将使钨合金镀层也沉积在这些橡胶材料上。
作为优化：所述的疏水性橡胶层是由于橡胶分子链上羧基、羟基、羰基、氨基、酰胺基、腈基、硝基、卤基、巯基、磺酸根和苯磺酸根含量低，从而使橡胶表面的水接触角大于65°的橡胶材料构成；或者，所述的疏水性橡胶层是由于橡胶中不含或含有少量的亲水性的填料或添加剂，从而使橡胶表面的水接触角大于65°的橡胶材料构成。
作为优化：所述的疏水性橡胶层由非极性或极性弱的橡胶制备而成；优先选用三元乙丙橡胶、甲基乙烯基硅橡胶或甲基乙烯基苯基硅橡胶。
三元乙丙橡胶、甲基乙烯基硅橡胶和甲基乙烯基苯基硅橡胶是非极性橡胶，疏水性强，同时它们的耐候性好，在大气中能长期保持良好的弹性，因此，它们是所述的疏水性橡胶层的优先使用的材料。高腈基含量的丁腈橡胶和氢化丁腈橡胶、端羧基液体丁腈橡胶、氯磺化聚乙烯橡胶、氯醚橡胶、丙烯酸酯橡胶、聚氨酯橡胶等极性橡胶，以及亲水化的橡胶(如亲水性硅橡胶)和水膨胀橡胶等材料的极性大或含有大量亲水性物质，这些材料表面疏水性不 强。这些材料在含可溶性钨化合物的化学镀液中，钨合金镀层就会沉积在这些材料的表面。
疏水性橡胶层中的疏水性橡胶对水具有排斥能力，水不能在疏水性橡胶表面铺展开来。为了获得钨合金在金属材质上的选择性化学沉积，在由第一层疏水性橡胶层和第二层金属薄片的复合体中的橡胶材质的疏水性越高越好。在用镀液进行化学沉积时，为了使沉积在第一层疏水性橡胶层上的合金少得可以忽略不计，橡胶基材的水接触角需大于65°。这里所谓的选择性化学沉积，指的是钨合金镀层，选择性地沉积在金属材质上，而不沉积在橡胶材质上。橡胶分子链上羧基、羟基、羰基、氨基、酰胺基、腈基、硝基、卤基、巯基、磺酸根和苯磺酸根，将增大橡胶的极性和亲水性。特别是羧基、羟基、磺酸根和苯磺酸根，将极大的增大橡胶的极性和亲水性。如果在橡胶和金属的复合体中使用的是亲水性强的羧基橡胶，化学沉积将既可以发生在金属材质表面，也同时发生在橡胶材质表面。如果橡胶材质上有钨合金的沉积层，将不仅浪费化学镀的镀液，而且不利于橡胶材质与其它橡胶材质的热硫化粘合或热塑性粘合，而这种热硫化粘合或热塑性粘合是后续加工中所必需的。第一层疏水性橡胶层的存在，就是为了第一层疏水性橡胶层和其它橡胶进行热硫化粘合或热塑性粘合，从而制备包含触点的橡胶按键。
因此，必需限制这些极性基团在橡胶基材中的含量，以获得选择性良好的钨合金化学沉积。为了获得选择性最佳的化学沉积，橡胶基材中不能含有这些基团。同样的道理，橡胶材质本体或表面不含或少量含有亲水性强的填料、添加剂或表面活性剂，也有利于获得选择性的化学沉积。
三元乙丙橡胶、甲基乙烯基硅橡胶、甲基乙烯基硅苯基橡胶是非极性的或极性很弱的、疏水性比较强的橡胶材料，适宜于和金属薄片进行复合制备层状复合体。在使用前述的化学镀液进行化学镀时，化学沉积不发生在橡胶层上。
作为优化：所述的第二层的金属薄片层为具有凸点或凹点的金属片材，具有凸线条或凹线条的金属片材、具有凸面或凹面的金属片材、具有面积小于1mm2的小孔的金属片材、金属网、金属泡沫或者金属纤维烧结毡，以便与PCB上的触点接触压强更大，导通性更好；金属材质为镁、铝、钛、铬、锰、铁、钴、镍、铜、锌、铌、钼、银、锡、金或含有这些元素的合金；所述的金属薄片层是由单一的金属材质或者不同的金属材质的层状复合形成的；优选在大气中化学性能稳定、电导率较高且价格比较低的金属或合金，如不锈钢或镍合金。
作为优化：所述的第二层的金属薄片由0.01-1.0mm厚的不锈钢、铜或铜合金、镍或镍合金薄片构成，在不锈钢、铜或铜合金、镍或镍合金薄片的一面或两面，镀有0.01-10微米的纯镍层或镍合金层；不锈钢、铜或铜合金、镍或镍合金薄片上的镍合金层由真空镀膜、电镀或化学镀的方法制备。
在不锈钢、铜或铜合金、镍或镍合金薄片上镀一纯镍层或镍合金层，可以提高金属薄片 与钨合金镀层的粘合强度，避免钨合金镀层在触点使用过程中脱落。特别是铜和铜合金薄片，宜在化学沉积钨合金镀层之前，在铜和铜合金薄片的两面镀上一薄层纯镍层或镍合金，以提高铜和铜合金的耐氧化、耐化学腐蚀的性能。
所选用的不锈钢是普通不锈钢、耐酸钢、或者添加了钼元素的从而改善耐大气腐蚀性的，特别是耐含氯化物大气的腐蚀的特种不锈钢。
金属薄片的厚度不宜过薄。如果第二层的金属薄片厚度低于0.01mm，就可不能很好地支撑第三层的钨合金镀层，在与橡胶复合之前、之中或之后的加工中容易破裂。如果第二层的金属薄片太厚，就会增加触点的整体硬度，同时浪费金属材料。所以，金属薄片的厚度，不宜大于1.0mm。
预先将第一层的疏水性橡胶层和第二层的金属薄片制成层状复合体，是为了方便将层状复合体作为触点应用于制备橡胶按键。层状复合体上的疏水性橡胶，可直接与其它橡胶进行热硫化粘合或热塑性粘合而形成橡胶按键。如果将没有橡胶层的金属薄片和其它橡胶进行热硫化粘合和热硫化成型、或热塑性粘合和热塑性成型从而形成橡胶按键，就会在模塑过程中发生溢胶、粘合不良等现象。所谓溢胶现象，是指在模塑过程中，橡胶溢到触点的正面，从而影响触点的导电性能。触点上有溢胶现象，对触点的质量来说是不可接受的。
第二发明目的：提供上述耐开关电弧烧蚀的触点的一种制备方法。
第二技术方案：一种耐电弧烧蚀的开关触点的制备方法，包括如下步骤：
(1)金属薄片的处理：金属薄片为0.01mm至1.0mm厚的不锈钢、铜或铜合金、镍或镍合金薄片；用清洗剂和有机溶剂对金属薄片进行除油、清洗；或通过喷砂、打磨将金属薄片进行表面机械粗化处理；或通过化学蚀刻处理以处理出直径小于1mm的凹坑或凸点；或在金属薄片的一面或两面，用电镀或化学镀的方法镀有0.1微米至10微米的纯镍层或镍合金层；然后用清洗剂和有机溶剂对所得到的金属薄片进行除油、清洗；
(2)疏水性橡胶与金属薄片的粘合处理：疏水性橡胶通过热硫化粘合和热硫化成型，粘合在涂有底涂剂或粘合促进剂的金属薄片上，形成层状的复合片材；或者将具有自粘性疏水性橡胶，通过热硫化成型，粘合在涂有底涂剂或没有底涂剂的金属薄片上，形成层状的复合片材；
(3)切割处理：将上述步骤中的复合片材分割或冲切成包含有疏水性橡胶层和金属薄片层的直径为2-10mm的圆柱体，或者将上述步骤中的复合片材分割或冲切成横截面为椭圆形、多边形、十字形、星形、新月形或它们的任意组合的物体；用碱性清洗液清洗约5分钟，水洗后，用5％的盐酸清洗3分钟，然后用去离子水清洗干净，滤干；
用5％的盐酸清洗的目的，是为了除去部分金属基材表面的氧化物，使金属基材表面活化，增强金属基材和钨合金镀层之间的结合强度。使用其它清洗和酸液活化方法，也是可行的。
(4)钨合金镀层的制备：将上述圆柱体或物体，浸渍在含有可溶性钨化合物的化学镀液中，搅拌，用化学镀的方法在圆柱体或物体的金属表面形成钨合金镀层；或者，将上述圆柱体放入含有可溶性钨化合物的化学镀液的滚筒中，让滚筒转动，用化学镀的方法在圆柱体的金属表面形成钨合金镀层；
镀液中含有40-125g/L的可溶性钨化合物、0-60g/L的可溶性的过渡金属铁、镍、钴、铜或锰的化合物或这些化合物的任意组合、0-30g/L的可溶性的锡、锑、铅或铋化合物或这些化合物的任意组合、20-100g/L的还原剂、30-150g/L的络合剂、20-100g/L的pH值调节剂、0.1-1g/L的稳定剂、0.1-1g/L的表面活性剂、0-50g/L的光亮剂或粗糙度调节剂；还可在镀液中添加其它助剂，如化学镀加速剂。加速剂可选用氟化钠。氟化钠即可以作为加速剂，同时亦可增加镀层的光亮度；
优选选用次亚磷酸钠作为还原剂。当用次亚磷酸钠作为还原剂时，制得钨合金镀层所采用化学镀的温度为65-85℃，时间为30-300分钟，镀液的pH值为8.0-10.0。
(5)清洗、烘干：取出上述被镀钨，用蒸馏水或去离子水清洗多次、沥干、在75℃的恒温烘箱中烘干，即得等到金属面层上镀有钨合金的开关触点。
作为优化：所述的含钨合金镀层所采用化学镀的温度为70-80℃，时间为100-200分钟，镀液的pH值为8.5-9.0；镀液中含有具有pH缓冲能力的强碱弱酸盐；所述的pH调节剂为氢氧化钠、氢氧化钾、碳酸钠、乙酸钠、氨水、焦磷酸钠、焦磷酸钾中的一种或多种，优先使用氨水或氢氧化钠溶液调节镀液的pH值。
化学镀的时间的选定，与开关产品的耐电弧烧蚀的性能要求或使用寿命要求有关。化学镀的时间越长，沉积在金属基材上的钨合金镀层就会越厚。较厚的钨合金镀层有利于触点的耐开关电弧性能。但化学镀的时间并不是越长越好。化学镀的时间过长，不仅生产效率低，而且偏碱性的化学镀液，可能会伤害第一层的疏水性橡胶层和第二层的金属薄片层之间的粘合强度，甚至造成脱层现象。作为优选，如果要求在500mA的导通电流下开关次数可在1万次以上，所述钨合金镀层所采用化学镀的时间为200分钟。
本发明中，所述的可溶性钨化合物是钨酸钾、钨酸钠、钨酸铵、二钨酸铵、四钨酸铵、七钨酸铵、八钨酸铵中的一种或多种。也可选用三氧化钨或钨酸。虽然三氧化钨或钨酸不溶于中性的水，但它溶于碱性水。选用三氧化钨或钨酸时，需先用氢氧化钠碱溶液或pH大于12的氨水使之先溶解，然后用溶解了的钨酸或三氧化钨配置化学镀液。优先选用易溶解于水且价格价较低的钨酸钠配制化学镀液。
所述的可溶性过渡金属铁、钴、镍、铜或锰的化合物是硫酸亚铁、硫酸亚铁铵、硫酸钴、氯化钴、硝酸钴、硫酸钴铵、碱式碳酸钴、氨基磺酸钴、乙酸钴、草酸钴、硫酸镍、氯化镍、硝酸镍、硫酸镍铵、碱式碳酸镍、氨基磺酸镍、乙酸镍、次磷酸镍、次亚磷酸镍、氢氧化镍、硫酸铜、氯化铜、硝酸铜、水合碱式碳酸铜、乙酸铜、硫酸锰或氯化锰中的一种或多种。使用氢氧化镍时，先用氨水使之溶解。我们在镀钨合金时发现，在化学镀液中使用硫酸镍和碱 式碳酸镍复配作为镍的前体，可使镀得的钨合金层具有较明亮的银白色，所得钨合金镀层的表面电阻较低。
镀液中可加入铁、钴、镍、铜或锰以外的其它可溶性过渡金属元素的化合物，以及可溶性主族元素的化合物如锡化合物、锑化合物、铋化合物和铅化合物，但应注意这些化合物对化学镀对所沉积的基材的选择性的影响。此外，也要注意这些化合物的生理毒性、环境毒性和危险特性。比如，应尽量少用或不用对人体和环境有害的可溶性铅化合物。虽然银是电触头或触点中常用的元素，但不建议在钨合金镀液中加入硝酸银等可溶性银化合物。因为我们在实验中发现，在钨合金镀液中加入一定量的硝酸银(如5g/L)后，对第一层的疏水性橡胶层和第二层的金属薄片层的层状复合体进行化学镀时，所发生的化学沉积，将不仅发生在第二层为的金属薄片层上，也发生在第一层的疏水性橡胶层上，这样化学沉积对基材就没有选择性。当沉积时间足够长时，用肉眼就可清楚地看到疏水性橡胶层上和金属薄片层上都有灰黑色或银白色的沉积层。用X射线荧光光谱分析，发现金属薄片层的表面和疏水性橡胶层的表面都含有大量的银。使用同样的配方取消硝酸银的加入后，则在化学镀的过程中，化学沉积层只生成在金属薄片层的金属面上。
作为优化：所述的还原剂为次亚磷酸钠、硼氢化钠、烷基胺硼烷、肼中的一种或多种。如果以硼氢化物或氨基硼烷为还原剂时，钨合金镀层中将含有少量的硼(质量分数可达7％)。以肼作还原剂，所得到的镀层中非金属(磷或硼)的含量几乎为零，金属含量可达到99％以上。选用次亚磷酸钠作为还原剂有很好的性价比，其毒性也较低。选用次亚磷酸钠为还原剂时，由于有磷析出，发生磷与金属的共沉积，镀层中除有金属钨和其它金属元素外还含有少部分的磷(质量分数可达l5％)。磷对触点的导电性是有害的，并且可能伤害钨合金的耐腐蚀性能，因此，必需控制钨合金中的磷含量。通过控制次亚磷酸钠的浓度、络合剂的浓度、pH值等措施，可以控制镀层中的磷含量。控制控制磷含量可得到致密、无孔的钨合金镀层。选用次亚磷酸钠作为还原剂，我们所得到的钨合金镀层和钨合金镀层之间的接触电阻，比99.5％的纯镍和99.5％的纯镍之间的接触电阻小，所得到的镀层能显著提高金属基材的耐开关电弧性能。
作为优化：所述的络合剂为柠檬酸钠、柠檬酸铵、酒石酸钠、酒石酸钾钠、乙二胺四乙酸二钠盐、乙二胺四乙酸四钠盐中的一种或多种。络合剂的作用是控制可供反应的游离金属离子的浓度，提高镀液稳定性，延长镀液寿命，提高镀层质量。络合剂对沉积速率、磷含量和耐腐蚀性等均有影响。
pH调节剂为氢氧化钠、氢氧化钾、碳酸钠、碳酸氢钠、乙酸钠、硫酸铵、氨水、焦磷酸钠、焦磷酸钾中的一种或多种。优先使用氨水或氢氧化钠溶液调节镀液的pH值。这样能够获得结合力更强、更稳定，镀层质量更好的钨合金镀层。化学镀的时间越长，沉积在金属基材上的钨合金镀层就会越厚。较厚的钨合金镀层有利于触点的耐开关电弧性能。但化学镀的时间并不是越长越好。化学镀的时间过长，不仅生产效率低，而且带碱性的化学镀液，可能会 伤害第一层的疏水性橡胶层和第二层的金属薄片层之间的粘合强度，甚至造成脱层现象。当采用次亚磷酸钠作为还原剂时，pH值不可大于12，因为过高的pH虽然使沉积速度加快，但使得镀层或沉积层和金属基材之间的附着力变差，使镀层或沉积层的颜色变深，甚至变成黑色。在镀液中可加入强酸弱碱盐或强碱弱酸盐，作为镀液的pH缓冲剂。
作为优化：在不考虑颜色、光泽时，所述的稳定剂为碘化钾、碘酸钾、苯骈三氮唑、4,5-二硫代辛烷-1,8-二磺酸盐、3-巯基-1-丙磺酸盐、硫代硫酸钠、硫脲中的一种或多种的混合物。所述的光亮剂(或表面粗糙度调节剂)可为市售的其它化学镀光亮剂中的一种或多种。在考虑颜色、光泽时，所述的稳定剂优选为硫代硫酸钠、硫脲或者两者的混合物，使得钨合金镀层同时具有良好的金属光泽。稳定剂的作用是抑制化学镀过程中所发生的自催化反应从而稳定镀液，防止激烈的自催化反应、防止生成大量含磷的黑色金属粉末。但稳定剂是化学镀的毒化剂，即反催化反应，所以不能过度使用，需控制其在镀液中的用量，以免影响化学镀效率。
作为优化：所述的化学镀采用的镀液中，还含有0.1-1g/L的表面活性剂；所述的表面活性剂为：十二烷基苯磺酸盐、十二烷基硫酸盐、正辛基硫酸钠中的一种或多种的表面活性剂；作优先为：十二烷基硫酸钠或十二烷基苯磺酸钠。加入些表面活性剂有助于镀件表面气体的溢出，降低镀层的孔隙率，使镀层致密，从而增加镀层的耐电弧性能。
作为优化，所述的化学镀采用的镀液中，还可含有最多至50g/L的光亮剂或粗糙度调节剂；所述的光亮剂或粗糙度调节剂为甲醛、乙醛、β-萘酚、2-甲基醛缩苯胺、苄叉丙酮、枯茗醛、二苯甲酮、氯苯甲醛、平平加、西佛碱、丁炔二醇、丙炔醇、1-二乙胺基丙-2-炔、乙氧化丙炔醇、邻磺酰苯甲酰亚胺、邻磺酰苯酰亚胺钠、乙烯基磺酸钠、丙炔磺酸钠、吡啶-2-羟基丙磺酸内盐、烷基酚聚氧乙烯醚或市售的商品化的电镀或化学镀光亮剂。加入光亮剂，可得到银白色的光亮的难熔金属合金的镀层。可通过不同的光亮剂复配，提高光亮剂的效率，减少光亮剂的用量。
本发明中，使用疏水性橡胶层和金属薄片层的复合体，用上述镀液进行化学镀，可使钨合金镀层沉积在金属的表面。我们用X射线荧光光谱仪(XRF)检测金属表面的钨元素含量，可以发现，在同一镀液中，随着化学镀时间的延长，在金属表面检测到的钨信号越来越强。钨信号越来越强，意味着钨合金镀层随着化学镀时间而越来越厚。但即使化学镀时间长达300分钟，在疏水性橡胶表面检测到的钨信号基本上为零。
有益效果：本发明在疏水性橡胶层和金属薄片的层状复合体上以化学镀的方法选择性地镀上一层含钨的合金，可有效地提高金属薄片的导电性和耐开关电弧烧蚀性能。由不锈钢片(如SS304不锈钢片)、镍片(如N6镍片)、镍合金片(如NCu30镍铜合金片)制得的镀有钨合金层的触点，与印刷电路板(PCB)上的镀金触点接触，触点间的接触电阻，比没有镀钨合金的同类触点与印刷电路板(PCB)上的镀金触点间的接触电阻小，具有较好的导通性能。由没有镀钨合金的不锈钢片或镍片制得的触点与PCB镀金触点通过300毫安的直流电，室温下 连续开关约4000次后，由于存在开关时的电弧烧蚀，小圆片和PCB镀金触点之间的接触电阻就明显升高(由约1Ω升高至100Ω以上，甚至不导通)；而在同样的电路条件下，按本发明镀有钨合金的同类触点与PCB触点通过500毫安的直流电，开关约30000次后，触点和PCB触点之间的接触电阻，仍在1Ω以下。
这种镀有钨合金的触点，与镀有黄金、铂或白银的开关触点比较，能够通过或承受更大的电流，具有更好的耐电弧烧蚀性能。而且，金属钨的价格比黄金、铂或银低很多。
调节镀液的配方组成和化学镀的时间和温度，所得的触点可以有类似于黄金、银、白银、钢或某些氮化钛的颜色、光泽等外观效果。本发明中的钨合金触点含有疏水性橡胶层，具有易于与橡胶进行热硫化粘合和成型从而制成含触点的橡胶按键产品的特性。
本发明的产品适用于各种高档场所，尤其适合于制作汽车、电动工具、游戏机等电器电子设备中，在按键下需要大电流(大于50mA的电流)通过的开关触点。
附图说明
图1是本发明的一种剖面结构示意图；图中：1、橡胶层；2、金属薄片层；3、钨合金镀层；
图2是本发明的制备方法中一种工艺流程图。
具体实施方式
下面结合具体实施例对本发明作进一步说明。
实施例1：
以下是制备钨合金镀层的触点的实施例。
镀液组成：钨酸钠100g/L、次亚磷酸钠35g/L、柠檬酸钠50g/L、酒石酸钾钠30g/L、硫酸铵30g/L、焦磷酸钠24g/L、碘酸钾40mg/L、硫代硫酸钠32mg/L、十二烷基硫酸钠1g/L。氨水适量加入，使镀液的pH值维持在8.5至9.5之间。
工艺路线：
以0.1mm厚、HV硬度为120至180、含铜量约55％的锌白铜片材为金属基材，作成金属薄片层2。选用锌白铜的原因是由于锌白铜具有优良的综合机械性能，耐腐蚀性优异、冷热加工成型性好、适用于制造各种弹性元件。将平滑的锌白铜片材用机械法滚压成有细波纹状的片材，波纹峰高为0.2mm，峰间距为0.4mm。用工业酒精进行清洗除油，然后用pH值为9左右的碱性清洗液在60℃下进行进一步的清洗除油，水洗，然后用12.5％的硫酸溶液在50至70℃的温度下清洗1分钟，水洗，然后，在锌白铜细波纹状的片材的两面，以化学镀的方式，镀上厚度为2.5至5.0μm厚的镍层。将镀有镍层的细波纹状的锌白铜片材用去离子水清洗干净，冷风吹干。
将一种甲基乙烯基苯基硅橡胶(例如选用德国瓦克公司生产的
Figure PCTCN2015084164-appb-000001
R 401/60)和乙烯基三特丁基过氧硅烷(VTPS)、过氧化二异丙苯(DCP)用开炼机混炼均匀。VTPS在混炼胶中的含量是1％，DCP在混炼胶中的含量是0.5％。VTPS是一种含有不稳定的过氧化合物成份 的偶联剂，它既可以使含乙烯基的硅橡胶交联，同时也促进含乙烯基的硅橡胶与金属之间的粘合。
将镀有镍层的细波纹状的锌白铜片材和上述混炼胶在165℃下进行热硫化粘合和热硫化成型，硫化时间为10分钟。形成1.25mm厚的锌白铜和硅橡胶的层状复合片材。制得此复合片材的模具的模腔，是在模腔表面涂有特氟龙的。将此复合片材冲切成直径为5mm的小圆粒。把这种小圆粒用碱性清洗液清洗数分钟，水洗，然后用5％的盐酸浸泡3分钟，最后放在10％的稀硫酸中活化1分钟，然后用去蒸馏水或离子水清洗，干燥。
将这样的500粒小圆片，放入80℃的上述300ml镀液中，搅拌，200分钟后取出，用蒸馏水或去离子水漂洗、沥干、放在70℃恒温烘箱里烘干，即得到在金属薄片层2上镀有钨合金的小圆粒。在化学钨的过程中，应时刻注意溶液的pH值变化情况，及时用氨水或氢氧化钠溶液控制溶液的pH值，使pH值保持在8.5至9.5之间。所镀钨合金的厚度及致密度与小圆粒在镀液中放置的时间有关。放置的时间越长，钨合金镀层3的厚度越厚。钨合金只在小圆粒中的不锈钢表面沉积，不在小圆粒中的橡胶层1表面沉积，如图1所示。
这种含有硅的橡胶层1的镀有钨合金的小圆粒，和硅橡胶热硫化粘合(小圆粒中的硅橡胶面和其它硅橡胶热硫化粘合，镀有钨合金的一面朝外)，可以用作橡胶按键中用作电路开关的触点，该触点与印刷电路板(PCB)的镀金触点接触，触点间的接触电阻比直接由不锈钢片制得的小圆粒与PCB的镀金触点之间的接触电阻低，而且这种镀有钨合金的小圆粒有更好的导通稳定性：由没有钨合金镀层3的不锈钢制得的小圆粒与PCB镀金触点通过300毫安的直流电，开关约2000次后，由于电路接通和断开时的电弧烧蚀，小圆粒和PCB镀金触点之间的接触电阻就明显升高(由约1Ω升高至100Ω以上，多次试验时甚至可以出现不导通的情况)；而在同样的电路条件下，这种镀有钨合金的小圆粒与PCB镀金触点通过300毫安的直流电，开关约10000次后，这种小圆片和PCB镀金触点之间的接触电阻，仍在1Ω以下。
实施例2：
以下是制备含钨合金镀层的触点的实施例。
镀液组成：钨酸钠90g/L、硫酸镍10g/L、碱式碳酸镍16g/L、次亚磷酸钠25g/L、柠檬酸钠50g/L、酒石酸钾钠30g/L、硫酸铵30g/L、焦磷酸钠24g/L、碘酸钾40mg/L、硫代硫酸钠32mg/L、十二烷基硫酸钠1g/L、邻磺酰苯酰亚胺钠20g/L。氨水适量加入，使镀液的pH值维持在8.5至9.5之间。
工艺路线：
如图2所示，将0.075mm厚的平整的不锈钢片(型号304)进行碱性除油和阳极除油，然后先用自来水清洗，再用蒸馏水和酒精清洗干净，将其一面用一种橡胶-金属粘合剂(选用美国罗门哈斯公司生产的Megum 3270)进行底涂处理，然后，将底涂处理过的这一面，和一种甲基乙烯基硅橡胶(例如选用日本信越公司生产的KE 951U)进行热硫化粘合，形成1.0mm厚的不锈钢-硅橡胶复合片材。将此复合片材冲切成直径为5mm的小圆粒。
把这种小圆粒用70℃下的碱性清洗液清洗约5分钟，水洗，然后用5％的盐酸清洗3分钟，然后用去离子水清洗干净，滤干。
将这样的500粒小圆片，放入80℃的上述300mL镀液中，搅拌，240分钟后取出，用蒸馏水或去离子水漂洗、沥干、冷风吹干或放在70℃恒温烘箱里烘干，即得到金属薄片层2镀有钨合金的小圆粒。在化学钨的过程中，应时刻注意溶液的pH值变化情况，及时用氨水或氢氧化钠溶液控制溶液的pH值，使pH值再8.5至9.5之间。所镀钨合金的厚度与小圆粒在镀液中放置的时间有关。放置的时间越长，钨合金镀层3的厚度越厚。钨合金只在小圆粒中的不锈钢表面沉积，不在小圆粒中的橡胶层1表面沉积，如图1所示。
这种镀有钨合金的小圆粒，使用加热模压的方式和硅橡胶热硫化粘合(小圆粒中的硅橡胶面和其它硅橡胶热硫化粘合，镀有钨镍合金的一面朝外)，可用作橡胶按键中用作电路开关的触点，该触点与印刷电路板(PCB)的镀金触点接触，触点的接触电阻比直接由不锈钢片制得的小圆粒与PCB的镀金触点之间的接触电阻低，而且这种镀有钨合金的小圆粒有更好的导通稳定性：由没有钨合金镀层3的不锈钢制得的小圆粒与PCB镀金触点通过300毫安的直流电，开关约2000次后，由于存在开关时的电弧烧蚀，小圆粒和PCB镀金触点之间的接触电阻就明显升高(由约1Ω升高至100Ω以上，多次试验时甚至可以出现不导通的情况)；而在同样的电路条件下，这种镀有钨合金的小圆粒与PCB镀金触点通过500毫安的直流电，开关约20000次后，这种小圆片和PCB镀金触点之间的接触电阻，仍在1Ω以下。
实施例3：
以400目的不锈钢平纹网(不锈钢型号为304)代替实施例2中的不锈钢片，采用实施2中的工艺和化学镀液，所制得的触点，也具有较低的接触电阻和较好的耐电弧烧蚀性能。
400目的不锈钢网网孔很小，在和硅橡胶模压时，硅橡胶不会穿透不锈钢网的网孔。如果选用目数小的不锈钢网，如80目以下的不锈钢网，在模压时就会产生硅橡胶穿透不锈钢网孔的工艺问题。因此，需采用加大目数的不锈钢网来制备有钨合金镀层3的触点。
对于本技术领域的普通技术人员来说，在不脱离本发明原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也应视为本发明的保护范围。

Claims (10)

  1. 一种耐电弧烧蚀的钨合金开关触点，其特征在于：开关触点是具有三层结构的层状复合体；第一层为0.1-10mm厚的疏水性橡胶层，第二层为0.01-1.0mm厚的含镁、铝、钛、铬、锰、铁、钴、镍、铜、锌、铌、钼、银、锡或金的金属薄片层，第三层为2×10-5-0.02mm厚的钨合金镀层；其中，第三层钨合金镀层是第一层和第二层的复合体浸渍在含有可溶性钨化合物的化学镀液中，用化学沉积的方法将钨合金沉积在第一层和第二层的复合体中第二层的表面而形成的；第三层钨合金镀层中含有重量比不小于30％的钨元素。
  2. 根据权利要求1所述的耐电弧烧蚀的钨合金开关触点，其特征在于：所述的疏水性橡胶层是由于橡胶分子链上羧基、羟基、羰基、氨基、酰胺基、腈基、硝基、卤基、巯基、磺酸根和苯磺酸根含量低，从而使橡胶表面的水接触角大于65°的橡胶材料构成；或者，所述的疏水性橡胶层是由于橡胶中不含或含有少量的亲水性的填料或添加剂，从而使橡胶表面的水接触角大于65°的橡胶材料构成。
  3. 根据权利要求1或2所述的耐电弧烧蚀的钨合金的开关触点，其特征在于：所述的疏水性橡胶层由非极性或极性弱的橡胶制备而成；优先选用三元乙丙橡胶、甲基乙烯基硅橡胶或甲基乙烯基苯基硅橡胶。
  4. 根据权利要求1所述的耐电弧烧蚀的钨合金开关触点，其特征在于：所述的金属薄片层为具有凸点或凹点的金属片材、具有凸线条或凹线条的金属片材、具有凸面或凹面的金属片材、具有面积小于1mm2的小孔的金属片材、金属网、金属泡沫或者金属纤维烧结毡；金属材质为镁、铝、钛、铬、锰、铁、钴、镍、铜、锌、铌、钼、银、锡、金或含有这些元素的合金；所述的金属薄片层是由单一的金属材质或者不同的金属材质的层状复合形成的。
  5. 根据权利要求1-4任意一项所述的耐电弧烧蚀的钨合金开关触点，其特征在于：所述的金属薄片层的金属薄片由0.01-1.0mm厚的不锈钢、铜或铜合金、镍或镍合金薄片构成，在不锈钢、铜或铜合金、镍或镍合金薄片的一面或两面，镀有0.01-10微米的纯镍层或镍合金层、纯钴层或钴合金层；不锈钢、铜或铜合金、镍或镍合金薄片上的纯镍层或镍合金层、纯钴层或钴合金层由真空镀膜、电镀或化学镀的方法制备。
  6. 一种耐电弧烧蚀的钨合金开关触点的制备方法，其特征在于：开关触点的制备包括如下步骤：
    (1)金属薄片的处理：金属薄片为0.01mm至1.0mm厚的不锈钢、铜或铜合金、镍或镍合金薄片；用清洗剂和有机溶剂对金属薄片进行除油、清洗；或通过喷砂、打磨将金属薄片进行表面机械粗化处理；或通过化学蚀刻处理以处理出直径小于1mm的凹坑或凸点；或在金属薄片的一面或两面，用电镀或化学镀的方法镀有0.1微米至10微米的纯镍层或镍合金层；然后用清洗剂和有机溶剂对所得到的金属薄片进行除油、清洗；
    (2)疏水性橡胶与金属薄片的粘合处理：疏水性橡胶通过热硫化成型的方法，粘合在涂有底涂剂或粘合促进剂的金属薄片上，形成层状的复合片材；或者将具有自粘性的疏水性橡胶，通过热硫化成型，粘合在涂有底涂剂或没有底涂剂的金属薄片上，形成层状的复合片材；
    (3)切割处理：将上述步骤中的复合片材分割或冲切成包含有疏水性橡胶层和金属薄片层的直径为2-10mm的圆柱体，或者将上述步骤中的复合片材分割或冲切成横截面为椭圆形、多边形、十字形、星形、新月形或它们的任意组合的物体；用碱性清洗液清洗5分钟，水洗后用5％的盐酸清洗3分钟，然后用去离子水清洗干净，滤干；
    (4)钨合金镀层的制备：将上述圆柱体或物体，浸渍在含有可溶性钨化合物的化学镀液中，搅拌，用化学镀的方法在圆柱体或物体的金属表面形成钨合金镀层；或者，将上述圆柱体放入含有可溶性钨化合物的化学镀液的滚筒中，让滚筒转动，用化学镀的方法在圆柱体的金属表面形成钨合金镀层；
    镀液中含有25-125g/L的可溶性钨化合物、0-60g/L的可溶性的过渡金属铁、镍、钴、铜或锰的化合物或这些化合物的任意组合、0-30g/L的可溶性的锡、锑、铅或铋化合物或这些化合物的任意组合、20-100g/L的还原剂、30-150g/L的络合剂、20-100g/L的pH值调节剂、0.1-1g/L的稳定剂、0.1-1g/L的表面活性剂、0-50g/L的光亮剂或粗糙度调节剂；
    优选次亚磷酸钠为镀液中的还原剂；采用次亚磷酸钠为还原剂时，所得钨合金镀层所采用化学镀的温度为60-85℃，时间为30-300分钟，镀液的pH值为8.0-10.0；
    (5)清洗、烘干：将被镀物取出，然后用蒸馏水或去离子水多次清洗、沥干、然后放在75℃的恒温烘箱中烘干，即得到金属面层上镀有钨合金的开关触点。
  7. 根据权利要求6所述的耐电弧烧蚀的钨合金开关触点的制备方法，其特征在于：所述的稳定剂为碘化钾、碘酸钾、苯骈三氮唑、4,5-二硫代辛烷-1,8-二磺酸盐、3-巯基-1-丙磺酸盐、硫代硫酸钠、硫脲中的一种或多种的混合物，优选为硫代硫酸钠、硫脲或者两者的混合物。
  8. 根据权利要求6所述的耐电弧烧蚀的钨合金开关触点的制备方法，其特征在于：所述的化学镀采用的镀液中，含有还原剂次亚磷酸钠、硼氢化钠、烷基胺硼烷、肼或三氯化钛中的一种或多种，优先选用次亚磷酸钠。
  9. 根据权利要求6所述的耐电弧烧蚀的钨合金开关触点的制备方法，其特征在于：所述的化学镀采用的镀液中，还含有0.1-1g/L的表面活性剂；所述的表面活性剂为：十二烷基苯磺酸盐、十二烷基硫酸盐、正辛基硫酸钠中的一种或多种的表面活性剂；优选为：十二烷基硫酸钠或十二烷基苯磺酸钠。
  10. 根据权利要求6所述的耐电弧烧蚀的钨合金开关触点的制备方法，其特征在于：镀液中还可含有最多至50g/L的光亮剂或粗糙度调节剂；所述的光亮剂或粗糙度调节剂为甲醛、乙醛、β-萘酚、2-甲基醛缩苯胺、苄叉丙酮、枯茗醛、二苯甲酮、氯苯甲醛、平平加、西佛碱、丁炔二醇、丙炔醇、1-二乙胺基丙-2-炔、乙氧化丙炔醇、邻磺酰苯甲酰亚胺、邻磺酰苯酰亚胺钠、乙烯基磺酸钠、丙炔磺酸钠、吡啶-2-羟基丙磺酸内盐、烷基酚聚氧乙烯醚或市售的商品化的化学镀光亮剂中的一种或多种。
PCT/CN2015/084164 2014-07-21 2015-07-15 一种耐电弧烧蚀的钨合金开关触点及其制备方法 WO2016011908A1 (zh)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117779011A (zh) * 2024-02-23 2024-03-29 昆山一鼎工业科技有限公司 一种晶圆化学镀钨合金溶液、配制方法和化学镀方法

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104103435B (zh) 2014-07-21 2016-07-13 南通万德科技有限公司 一种耐电弧烧蚀的钨合金开关触点及其制备方法
CN104561959A (zh) * 2015-01-14 2015-04-29 江苏兴达钢帘线股份有限公司 促进化学镀锡青铜合金镀层形成的加速剂
JP6447475B2 (ja) 2015-11-30 2019-01-09 オムロン株式会社 接点部材、摺動接点、電気機器、および接点部材の製造方法
CN106409539A (zh) * 2016-08-30 2017-02-15 南通万德科技有限公司 一种聚合物基复合材料及其制备工艺
CN108807019A (zh) * 2017-08-14 2018-11-13 邓章初 开关用金属导电体及其制造方法
US10622509B2 (en) * 2017-12-18 2020-04-14 Ingentec Corporation Vertical type light emitting diode die and method for fabricating the same
CN109449014B (zh) * 2018-10-19 2020-12-04 南京理工大学 一种耐烧蚀平面三电极高压开关及其制备方法
CN114464473B (zh) * 2022-01-08 2023-08-01 浙江福达合金材料科技有限公司 一种高可靠性铆钉型电触头、成型设备及成型方法
CN116352100B (zh) * 2023-05-31 2023-07-28 赣州海盛钨业股份有限公司 一种高性能掺杂钨条的生产工艺

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3852879A (en) * 1968-09-25 1974-12-10 Mallory & Co Inc P R Electrical contact material
CN103547056A (zh) * 2012-07-12 2014-01-29 绿点高新科技股份有限公司 导电线路装置及其制造方法
CN103700517A (zh) * 2013-12-31 2014-04-02 南通万德科技有限公司 开关触点元件及其制备方法
CN104103435A (zh) * 2014-07-21 2014-10-15 南通万德科技有限公司 一种耐电弧烧蚀的钨合金开关触点及其制备方法

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3721778A (en) * 1971-06-21 1973-03-20 Chomerics Inc Keyboard switch assembly with improved operator and contact structure
US3862381A (en) * 1973-10-29 1975-01-21 Chomerics Inc Keyboard switch assembly with multilayer, coextensive contactor means
EP0234246A1 (de) * 1986-01-30 1987-09-02 Siemens Aktiengesellschaft Schaltkontaktstücke für Vakuumschaltgeräte und Verfahren zu deren Herstellung
US6436816B1 (en) * 1998-07-31 2002-08-20 Industrial Technology Research Institute Method of electroless plating copper on nitride barrier
US6399219B1 (en) * 1999-12-23 2002-06-04 Vapor Technologies, Inc. Article having a decorative and protective coating thereon
US7179546B1 (en) * 2004-12-03 2007-02-20 Vapor Technologies, Inc. Decorative and protective coating
DE602007010141D1 (de) * 2006-05-24 2010-12-09 Atotech Deutschland Gmbh Zusammensetzung zur stromlosen metallabscheidung und verfahren zur abscheidung von kupfer-zink-zinn,ignet ist
JP4719170B2 (ja) * 2007-02-28 2011-07-06 株式会社東芝 真空遮断器用接点材料の製造方法
CN100497685C (zh) * 2007-06-08 2009-06-10 东北大学 自蔓延熔铸-电渣重熔制备CuCr合金触头材料的方法
KR101501309B1 (ko) * 2007-09-26 2015-03-10 후루카와 덴키 고교 가부시키가이샤 가동 접점용 은 피복 복합 재료 및 그의 제조 방법
CN101696490A (zh) * 2009-11-02 2010-04-21 河南理工大学 一种纯铜表面磁控溅射制备耐磨抗电蚀合金层的方法
CN102522241B (zh) * 2011-12-12 2014-05-07 中铁电气化局集团有限公司 一种CuCr合金触头材料及其制备方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3852879A (en) * 1968-09-25 1974-12-10 Mallory & Co Inc P R Electrical contact material
CN103547056A (zh) * 2012-07-12 2014-01-29 绿点高新科技股份有限公司 导电线路装置及其制造方法
CN103700517A (zh) * 2013-12-31 2014-04-02 南通万德科技有限公司 开关触点元件及其制备方法
CN104103435A (zh) * 2014-07-21 2014-10-15 南通万德科技有限公司 一种耐电弧烧蚀的钨合金开关触点及其制备方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117779011A (zh) * 2024-02-23 2024-03-29 昆山一鼎工业科技有限公司 一种晶圆化学镀钨合金溶液、配制方法和化学镀方法
CN117779011B (zh) * 2024-02-23 2024-05-14 昆山一鼎工业科技有限公司 一种晶圆化学镀钨合金溶液、配制方法和化学镀方法

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