WO2016011913A1 - 一种含难熔金属合金镀层的开关触点及其制备方法 - Google Patents

一种含难熔金属合金镀层的开关触点及其制备方法 Download PDF

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Publication number
WO2016011913A1
WO2016011913A1 PCT/CN2015/084169 CN2015084169W WO2016011913A1 WO 2016011913 A1 WO2016011913 A1 WO 2016011913A1 CN 2015084169 W CN2015084169 W CN 2015084169W WO 2016011913 A1 WO2016011913 A1 WO 2016011913A1
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Prior art keywords
layer
alloy
nickel
refractory metal
rubber
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PCT/CN2015/084169
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English (en)
French (fr)
Inventor
韩辉升
王振兴
丁阳
张红梅
顾建祥
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南通万德科技有限公司
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Publication of WO2016011913A1 publication Critical patent/WO2016011913A1/zh

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    • 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
    • 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
    • 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

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).
  • 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 the switching arc phenomenon will cause the contacts to be oxidized and ablated, 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.
  • tungsten has the highest melting point.
  • the pure metals with a melting point higher than 1850 ° C are: tungsten (melting point 3410 ° C), cerium (melting point 3180 ° C), cerium (melting point 3045 ° C), cerium (melting point 2996 ° C), molybdenum (melting point 2610 ° C), bismuth (melting point 2468 °C), ⁇ (melting point 2227 ° C), vanadium (melting point 1900 ° C), chromium (melting point 1875 ° C) and zirconium (melting point 1852 ° C).
  • the refractory metal has a lower vapor pressure and a lower evaporation rate at high vacuum temperatures. The lower vapor pressure and evaporation rate of refractory metals is a consideration for our choice of alloys as contact materials.
  • the preparation methods of the refractory metal alloy include a powder metallurgy method, a vacuum arc melting method, and a vacuum electron bombardment melting method. It is most widely used in powder metallurgy because it is simple in process and can obtain fine grain ingots for further plastic processing.
  • the main process of the powder metallurgy method is: mechanically mixing the refractory metal powder (for example, tungsten powder and molybdenum powder) according to the ratio; pressing the raw material by a mechanical press or an isostatic pressing machine; and sintering in a high-temperature sintering furnace through hydrogen Alloy ingots.
  • the sintering temperature increases as the tungsten content increases, and the range is between 2150 and 2300 °C.
  • the sintered billet is rolled or forged material.
  • the preparation of alloys of refractory metals by these methods requires relatively expensive equipment, and the shape of the refractory metal alloy produced is also shaped.
  • 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. Silver is used as a point contact, and although the initial surface resistance is small, its service life in the atmosphere is also limited. Although the cost of silver plating is relatively low, 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 7,169,215 discloses a material and method for chemically depositing a copper-molybdenum alloy, and the resulting copper-molybdenum alloy containing no alkali metal ions and alkaline earth metal ions has a resistivity of less than 30 micro ohms/cm.
  • the alloy is deposited on a single silicon crystal, a silicon thermal oxide layer, and a copper and cobalt film on a silicon substrate.
  • the copper-molybdenum alloy can be used as a barrier layer between metal layers and an interconnect material on a chip. In these applications, the copper-molybdenum alloy can replace copper, but has a higher electrical resistivity than copper.
  • This invention discloses the activation of a substrate with a palladium solution followed by chemical deposition of copper molybdenum on various substrates. This invention does not involve selective chemical deposition.
  • the copper-molybdenum alloy has poor arc erosion resistance and is not an ideal arc-resistant ablation contact material.
  • U.S. Patent 4,019,910 discloses the preparation of an electroless plating bath of a multi-metal nickel alloy.
  • a multi-metal nickel alloy In addition to boron in the nickel alloy Or phosphorus, also containing 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 e.g., tungsten and/or molybdenum
  • a reducing agent e.g., a reducing agent
  • a specific surfactant etraalkylammonium hydroxide
  • this protective film is relatively hard and brittle due to the high cobalt content, and the surface resistance increases due to the cobalt oxide-based alloy easily generating cobalt oxide under the action of an electric arc.
  • This protective film is not resistant to arc ablation and should not be used to make electrical contacts or contacts.
  • 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.
  • 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 resistance, or to overcome copper-base, nickel-based or stainless steel contacts, although the cost is low but the arc resistance Poorly disadvantageous, a switch contact comprising a refractory metal alloy coating having low manufacturing cost, good conduction performance, and arc ablation resistance is provided.
  • the invention provides a switch contact comprising a refractory metal alloy plating layer, wherein the switch contact is a layered composite body having three layers of a layer structure, such as small cylindrical particles, prismatic particles or elliptical column particles,
  • the first layer is a 0.1-10 mm thick hydrophobic rubber layer
  • the second layer is a 0.01-1.0 mm thick metal foil layer
  • the third layer is a 2*10 -5 -0.02 mm thick refractory metal alloy chemical deposited layer.
  • the chemical deposition layer of the third layer of the refractory metal alloy is such that the composite of the first layer and the second layer is immersed in an electroless plating solution of a compound containing at least one soluble refractory metal, by chemical deposition a coating of a refractory metal alloy is deposited on the surface of the second layer of the composite of the first layer and the second layer; in the third layer or an outer layer of one third of the total thickness of the third layer, tungsten
  • the sum of the weight percentages of yttrium, lanthanum, cerium, lanthanum, molybdenum, niobium, tantalum, vanadium, chromium and zirconium is not less than 50%; and the transition metal containing not more than 50% by weight in the third layer of refractory metal alloy layer Elemental iron, nickel, cobalt, copper, manganese or any combination of these elements, weight 100 Any combination of no more than 10% tin, antimony, lead or bismuth or a ratio of
  • Tungsten is the preferred element for the preparation of refractory metal alloy coatings to provide excellent arc ablation resistance.
  • refractory metal elements other than tungsten it is preferred to use a molybdenum element having a higher melting point, a less toxic compound, a more abundant market supply, and a lower price, and an alloy of tungsten forming a refractory metal, that is, a tungsten-molybdenum alloy. Or molybdenum tungsten alloy.
  • the plating layer may contain a refractory metal element such as ruthenium, osmium, iridium, molybdenum, niobium, tantalum, vanadium, chromium or zirconium.
  • one or more electroless plating solutions may be used, such that the percentage of tungsten or other refractory metal elements in the refractory metal coating is stepped with the thickness of the coating. Variety.
  • refractory metal elements having a weight percentage of not less than 50% are contained to ensure good arc erosion resistance of the plating layer.
  • Tungsten-molybdenum alloys can be used at higher temperatures than pure molybdenum or molybdenum alloys.
  • a molybdenum-tungsten alloy is used as an electrode, a nozzle and a thimble component in a wave oven for producing a high-melting refractory ceramic fiber, the service life is much longer than that of a pure metal molybdenum product.
  • Molybdenum-tungsten alloys can also be used for gas rudders and shields of solid rocket motors due to their high melting point, ablation resistance and flame erosion resistance to solid particles.
  • Tungsten-molybdenum alloys combine some of the advantages of tungsten with some of the advantages of molybdenum.
  • the alloy can be used in a wide temperature range between molybdenum and tungsten. These factors are also the reasons why the tungsten-molybdenum alloy is preferentially used as the contact material in the present invention.
  • the use of the alloy as a contact material can, to a certain extent, combine the excellent arc erosion resistance of tungsten with the easy processing property of molybdenum.
  • the ions of transition metal elements such as iron, nickel, cobalt, copper, and manganese are added to the plating solution of the refractory metal alloy in order to firmly bond the plating layer to the metal substrate and to accelerate the speed 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 first layer is a 0.1-10 mm thick hydrophobic rubber layer.
  • the hydrophobic rubber layer is made of a hydrophobic rubber. Hydrophobic rubber has a repulsive ability to water, and water cannot spread on the surface of hydrophobic rubber.
  • a rubber material in a composite of a first layer of a hydrophobic rubber layer and a second layer of metal foil The higher the hydrophobicity, the better.
  • the water contact angle of the rubber substrate needs to be greater than 65°.
  • 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, an alloy of refractory metals will also be deposited on these rubber materials during electroless plating. In general, the stronger the hydrophobicity of the rubber material used, the more advantageous the refractory metal alloy is selectively chemically deposited on the metal surface of the rubber metal layered composite used in the present invention, not on the surface of the rubber material. Deposition.
  • 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 thermoset or thermoplastic.
  • the hydrophobic rubber layer is prepared from 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 with strong hydrophobicity, and they have good weather resistance and can maintain good elasticity in the atmosphere for a long time.
  • the metal foil is composited to prepare a layered composite. When electroless plating is performed using the aforementioned electroless plating solution, chemical deposition does not occur on the rubber layer. Therefore, they are the preferred materials for the hydrophobic rubber layer described.
  • selective chemical deposition refers to a refractory metal alloy coating that 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.
  • a hydrophilic carboxyl rubber is used in the rubber-metal composite, chemical deposition can occur on both the metal surface and the rubber surface. If the rubber material has a deposited layer of refractory metal 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 is necessary in subsequent processing.
  • the first layer of hydrophobic rubber layer is present for the purpose of thermally vulcanization bonding or thermoplastic bonding of the first layer of hydrophobic rubber layer with other rubbers to produce a rubber button comprising contacts.
  • 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, bismuth, molybdenum, silver, tin or gold or an alloy containing these elements; the second layer of metal foil is a single metal or a different metal layered composite; preferred conductivity is better High and relatively low cost metals or alloys.
  • 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 0.1-10 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 layer or a nickel alloy layer on a stainless steel, copper or copper alloy, nickel or nickel alloy sheet can improve the adhesion strength between the metal foil and the refractory metal alloy coating, and avoid the refractory metal alloy coating during the contact process. Falling off.
  • 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 before chemical deposition of the refractory metal alloy coating to improve the oxidation resistance and resistance of the copper and copper alloys. Chemical corrosion performance.
  • the above stainless steel is ordinary stainless steel, acid-resistant steel, or added with tungsten and molybdenum elements to improve 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 refractory metal 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, and the division or punching process becomes difficult, and 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 is thermally vulcanized or thermoplastically bonded to form a rubber button, an overflow phenomenon occurs 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 contact comprising a refractory metal alloy.
  • a second technical solution a method for preparing a switch contact comprising a refractory metal alloy, comprising the following steps:
  • the metal foil layer is 0.01-1.0 mm thick stainless steel, copper or copper alloy, nickel or nickel alloy flake, on one or both sides of stainless steel, copper or copper alloy, nickel or nickel alloy flakes, Or vacuum coating, plating or
  • the electroless plating method is plated with a pure nickel layer or a nickel alloy layer of 0.01-10 micrometers; the nickel alloy layer is preferably prepared by electroless plating;
  • the hydrophobic rubber layer is formed by thermal vulcanization and bonded to the metal foil layer coated with the primer or the adhesion promoter to form a composite sheet;
  • the self-adhesive hydrophobic rubber is formed by thermal vulcanization and bonded on a metal foil layer coated with a primer or without a primer to form a composite sheet;
  • the bath contains 20-150 g/L of soluble tungsten, lanthanum, cerium, lanthanum, molybdenum, niobium, tantalum, vanadium, chromium or zirconium compounds or any combination of these compounds, 0-60 g/L of soluble transition metal iron a compound of nickel, cobalt, copper or manganese or any combination of these compounds, 0-30 g/L of soluble tin, antimony, lead or antimony compound or any combination of these compounds, 20-150 g/L of reducing agent, 30 -150 g/L of complexing agent, 20-100 g/L of pH adjuster, 0.1-1 g/L of stabilizer, 0.1-2 g/L of surfactant, 0-50 g/L of brightener or roughness A modifier; other additives such as an 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
  • the electroless plating of the refractory metal alloy is performed at a temperature of 65-80 ° C for 45-270 minutes, and the pH of the plating solution is 8.5-9.5.
  • the soluble tungsten compound is one or more of sodium tungstate, potassium tungstate, ammonium tungstate, ammonium metatungstate, sodium phosphotungstate, tungstic acid, and tungsten trioxide.
  • the tungstic acid or tungsten trioxide which is insoluble in pure water is used as the tungsten source, the tungstic acid or tungsten trioxide is first dissolved with an alkali solution of sodium hydroxide, and then the electroless plating solution is disposed with the dissolved tungstic acid or tungsten trioxide. It is preferred to prepare an electroless plating solution by using sodium tungstate which is easy to dissolve and has a low price.
  • the soluble molybdenum compound is sodium molybdate, potassium molybdate, ammonium molybdate, phosphomolybdic acid, ammonium phosphomolybdate, molybdic acid, molybdenum trioxide.
  • a slightly water-soluble molybdic acid or water-insoluble molybdenum trioxide is used as a molybdenum source, it may be dissolved with a sodium hydroxide solution and then used to prepare an electroless plating solution.
  • the soluble compounds of the other refractory metals include sodium perrhenate, potassium perrhenate, ammonium perrhenate, potassium citrate, barium hydroxide or pentoxide pentoxide, potassium fluoroantimonate, potassium citrate, hydration. Cerium oxide, bismuth oxychloride octahydrate, potassium hexafluoroantimonate, sodium vanadate, sodium metavanadate, sodium orthovanadate, ammonium metavanadate, phthalic anhydride, potassium dichromate, chromium trioxide (used Previously dissolved in an alkali solution, potassium hexafluorozirconate, zirconyl nitrate, and the like.
  • the soluble nickel compound is one or more of nickel sulfate, nickel chloride, nickel nitrate, nickel ammonium sulfate, basic nickel carbonate, nickel sulfamate, nickel acetate, and nickel hypophosphite.
  • nickel hydroxide When using nickel hydroxide, it is first dissolved with ammonia water.
  • the nickel precursor in the electroless plating solution is compounded with nickel sulfate and basic nickel carbonate, so that the plated tungsten-molybdenum alloy layer has a bright silver-white color, and the obtained tungsten-molybdenum alloy coating layer is obtained.
  • the surface resistance is low.
  • the soluble cobalt compound is one or more of cobalt sulfate, cobalt chloride, cobalt nitrate, cobalt ammonium sulfate, basic cobalt carbonate, cobalt sulfamate, cobalt acetate, and cobalt oxalate.
  • the soluble copper compound is one or more of copper sulfate, copper chloride, copper nitrate, hydrated basic copper carbonate, and copper acetate.
  • soluble transition metal elements other than nickel, cobalt, and copper, and soluble tin compounds, antimony compounds, antimony compounds, and lead compounds may be added to the plating solution, but it should be noted that these compounds are electrolessly plated on the deposited substrate. The impact of selectivity. In addition, attention should be paid to the physiological toxicity, environmental toxicity and hazardous properties of these compounds. For example, soluble lead compounds that are harmful to humans and the environment should be used sparingly or not. Although 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-molybdenum alloy plating solution.
  • 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, hydrazine, and titanium trichloride. If borohydride or aminoborane is used as the reducing agent, the tungsten-molybdenum 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 coating contains a small amount of phosphorus in addition to the metal element.
  • Phosphorus is detrimental to the electrical conductivity of the contacts and may damage the corrosion resistance of the refractory metal alloy. Therefore, it is necessary to control the phosphorus content in the tungsten-molybdenum 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 coating of a refractory metal alloy such as a dense, non-porous tungsten-molybdenum alloy.
  • sodium hypophosphite having a lower priority and lower toxicity is preferred.
  • the contact resistance between the tungsten-molybdenum alloy coatings obtained by us is less than the contact resistance between the pure nickel and the nickel content of 99.5% or more and the pure nickel of 99.5% or more.
  • the resulting coating significantly improves the switching arc resistance of the metal substrate.
  • the use of sodium hypophosphite as a reducing agent has a good cost performance.
  • TiCl3 highly reductive titanium trichloride
  • the complexing agent is one or more of sodium citrate, ammonium citrate, sodium tartrate, sodium potassium tartrate, disodium edetate, and tetrasodium ethylenediaminetetraacetate.
  • the role of the complexing agent is to control the concentration of free metal ions available for reaction. Improve the stability of the bath, extend the life of the bath, and improve the quality of the coating.
  • Complexing agents have an effect on deposition rate, phosphorus content and corrosion resistance.
  • the pH of the plating solution is preferably 8.5 to 9.5. Due to the generation of by-product hydrogen ions during the electroless plating reaction, the pH of the plating solution is lowered. Use, in the process of electroless plating, need to add pH adjuster.
  • the pH adjusting agent is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, aqueous ammonia, sodium pyrophosphate, sodium acetate, and potassium pyrophosphate.
  • the pH of the bath is preferably adjusted with ammonia or sodium hydroxide solution. In this way, a tungsten-molybdenum alloy coating layer having stronger bonding strength, more stability, and better plating quality can be obtained.
  • ammonia or sodium hydroxide solution is also relatively cheap.
  • 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.
  • the plating solution In order to stabilize the plating rate and ensure the quality of the coating, the plating solution must have a buffering capacity to maintain the pH of the plating solution within a suitable range. Therefore, the plating solution contains a strong base weak acid salt as a pH buffer.
  • the stabilizers are potassium iodide, potassium iodate, benzotriazole, 4,5-dithiooctane-1,8-disulfonate, 3-mercapto-1. a mixture of one or more of 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 refractory metal 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, n-octyl
  • a surfactant is: dodecylbenzenesulfonate, lauryl sulfate, n-octyl
  • One or more surfactants in sodium sulfate preferably: sodium lauryl sulfate or sodium dodecylbenzene sulfonate.
  • 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 brightener or roughness modifier is formaldehyde, acetaldehyde, cuminaldehyde, chlorobenzaldehyde, ⁇ -naphthol, 2-methyl acetal, benzylideneacetone, benzophenone, pingpingjia, west Fosine, butynediol, propynyl alcohol, 1-diethylaminopropan-2-yne, ethoxylated propynyl alcohol, sulfonyl benzoimide, sodium sulfonimide, vinyl One or more of sodium sulfonate, sodium propyne sulfonate, pyridine-2-hydroxypropane sulfonate, alkylphenol ethoxylate or a commercially available commercial plating brightener. Two or more brighteners can be used at the same time to increase the brightening effect of the coating and reduce the amount of brightener.
  • 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 refractory metal alloy coating deposited on the metal substrate. Thicker refractory metal alloy coatings contribute to 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 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 electroless plating time of the refractory metal alloy plating layer is 200 minutes. Elevated electroless plating The temperature of the liquid will accelerate the rate of chemical deposition, but too high a bath temperature (above 90 ° C) will make the color of the electroless plating deeper and the adhesion of the coating to the metal substrate will decrease.
  • 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 refractory metal alloy plating layer on the surface of the metal.
  • XRF X-ray fluorescence spectrometer
  • the present invention selectively coats a layer of a refractory metal 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 Ablation performance.
  • Contacts made from stainless steel sheets or nickel sheets without refractory metal alloys are plated with gold-plated contacts of the PCB through 300 mA of direct current, and after continuous switching at room temperature for about 2000-4000 times, due to arc ablation during switching,
  • the contact resistance between the contacts made of these metal materials and the gold-plated contacts of the PCB is significantly increased (from about 1 ohm to more than 100 ohms, or even non-conducting); and under the same circuit conditions, according to the present Invented the same kind of contacts coated with tungsten-molybdenum alloy and the gold-plated contacts of the PCB through 300 mA of DC, after about 10,000 switching, the contact resistance between the contacts and the PCB contacts is still below 1 ohm.
  • a refractory metal alloy is relatively low in cost. Compared with gold or silver plated switch contacts, it can withstand higher currents and has better arc erosion resistance. Moreover, the preferred tungsten and molybdenum materials are much cheaper than gold, platinum or silver. In such a contact plated with a refractory metal alloy plating, since a part of tungsten is replaced by a molybdenum element, the raw material used for preparation is also low in cost.
  • the formulation composition of the plating solution and the time and temperature of the electroless plating are adjusted, and the obtained contact layer containing the refractory metal alloy plating layer may have an appearance effect similar to that of gold, silver, silver, steel or some titanium nitride.
  • the product of the invention is suitable for various low-voltage electrical appliances with strict requirements on the service life of the switch, and is particularly suitable for making switch contacts of electric appliances and the like, such as automobiles, electric tools, game machines, etc., which need to connect, carry and break currents greater than 50 mA. point.
  • the contacts prepared in the present invention contain a hydrophobic rubber layer.
  • the surface of the hydrophobic rubber layer has no alloy in which a refractory metal is deposited.
  • the presence of a hydrophobic rubber layer facilitates the thermal vulcanization bonding and thermal vulcanization molding of such contacts with other rubbers to produce a rubber button product with contacts.
  • Figure 1 is a schematic cross-sectional view of the present invention
  • Figure 2 is a process flow diagram of the preparation process of the present invention.
  • composition of the bath is:
  • Preparation of the plating solution The above various compounds are first dissolved in water or dissolved by heating, and then mixed together in proportion. Adjust the pH to 9.0 with ammonia water and dilute to the specified volume with water.
  • 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% was used as a metal substrate as the metal foil layer 2.
  • 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 0.1 mm and a peak pitch of 0.2 mm.
  • a nickel layer having a thickness of about 2.5 ⁇ m was plated by electroless plating using an electroless nickel plating bath containing nickel sulfate and sodium hypophosphite. Electroless nickel plating on metal substrates is a mature process and will not be described in detail herein.
  • the fine corrugated zinc white copper sheet coated with a nickel layer was washed with deionized water and dried by cold air.
  • VTPS vinyl tributyl butyl peroxysilane
  • DCP dicumyl peroxide
  • VTPS is a coupling agent containing an unstable peroxy compound component that crosslinks vinyl-containing silicone rubber and promotes vinyl-containing silicone rubber and metals (such as nickel, carbon steel, stainless steel, Bonding between copper, etc.).
  • the fine corrugated zinc white copper sheet coated with a nickel layer and the above-mentioned rubber compound were subjected to thermal vulcanization bonding at 165 ° C for heat-sealing molding, and the vulcanization time was 12 minutes.
  • a layered composite sheet of 1.25 mm thick zinc white copper and silicone rubber was formed.
  • the cavity surface of the mold of this composite sheet was obtained with a Teflon coating.
  • the presence of the Teflon coating prevents the rubber compound from sticking during hot vulcanization.
  • This composite sheet was die cut into small pieces having a diameter of 5 mm. The pellet was 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 min, then washed and drained.
  • the silicon wafer coated with a tungsten-molybdenum alloy is subjected to thermal vulcanization bonding and thermal vulcanization molding.
  • the silicone rubber face in the small wafer is thermally vulcanized and bonded to other silicone rubber, and the side coated with the tungsten-molybdenum alloy layer faces outward so that the tungsten-molybdenum alloy layer can be in contact with the contacts on the printed circuit board (PCB).
  • PCB printed circuit board
  • the contact is in contact with the gold-plated contacts on the PCB, has a stable and low contact resistance, and the small wafer coated with tungsten-molybdenum alloy has better conduction stability: no tungsten-molybdenum alloy coating Zinc white copper or zinc-plated copper plated with nickel-plated copper and gold-plated contacts of the PCB pass 300 mA of DC power. After about 3,000 switching, due to arc ablation during switching, small discs and PCB gold-plated contacts The contact resistance between the points is significantly increased (from about 1 ohm to more than 100 ohms, and even non-conduction may occur in multiple tests); and under the same circuit conditions, the tungsten-molybdenum is plated. The small wafer of the alloy and the gold-plated contacts of the PCB pass 300 mA of DC power. After about 10,000 switching, the contact resistance between the small wafer and the gold-plated contacts of the PCB is still below 1 ohm.
  • Preparation of the plating solution first dissolve the above various compounds in water, and heat to accelerate the dissolution progress.
  • titanium trichloride can be dissolved in water or a 10% hydrochloric acid solution.
  • the prepared titanium trichloride solution cannot be placed for a long time to avoid precipitation.
  • all the above solutions are mixed in proportion to form a mixed solution; the ferric chloride solution is added to the mixed solution in proportion and stirred uniformly; the pH is adjusted to 9.0 with ammonia water, and diluted with water. To the specified volume.
  • a 0.075 mm thick flat stainless steel sheet (Model 304) was subjected to alkaline degreasing and anode degreasing, and cleaned for use as a foil layer 2 with a rubber-metal binder on one side (Solomon, USA) Haze's Megum 14135) was primed and then heat treated with a base treated with a methyl vinyl phenyl silicone rubber (Elastosil R 401/60 from WACKER, Germany) Vulcanized bonding was used as the rubber layer 1 to form a 1.0 mm thick stainless steel-silicone rubber composite sheet. This composite sheet was die cut into small pieces having a diameter of 5 mm.
  • the pellet was washed with an alkaline cleaning solution for about 5 minutes, washed with water, then washed with 5% hydrochloric acid for 3 minutes, then washed with deionized water and filtered.
  • the tungsten molybdenum cobalt tin alloy is deposited only on the surface of the stainless steel in the small disc and is not deposited on the surface of the silicone rubber in the small wafer.
  • cobalt sulfate was added instead of nickel sulfate.
  • the precipitation of cobalt ions is slightly slower than the precipitation of nickel ions, so that it can be utilized.
  • the presence of the cobalt element achieves the purpose of good adhesion of the coating to the stainless steel substrate, and can also reduce the content of the transition metal having a lower melting point in the plating layer.
  • the purpose of adding stannous chloride to the plating solution is to obtain a soft chemical deposit layer in order to make the plating layer contain tin.
  • a softer chemical deposit such as the outer surface of a contact, will form a tighter contact with another contact that is in contact with it, such as a gold-plated contact on the PCB, and may reduce contact with it. The wear of the other contact.
  • This small disc coated with tungsten molybdenum cobalt tin alloy is thermally vulcanized and bonded with silicone rubber (the silicone rubber surface in the small wafer is thermally vulcanized and bonded to other silicone rubber, and the side coated with tungsten molybdenum cobalt tin alloy In addition, 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).
  • the contact resistance of the contact is smaller than that of a small wafer directly made of stainless steel.
  • the contact resistance between the gold-plated contacts of the PCB is low, and the small wafer coated with tungsten-molybdenum-cobalt-tin alloy has better conduction stability: a small circle made of stainless steel without tungsten-molybdenum-cobalt-tin alloy plating
  • the gold-plated contacts of the chip and the PCB pass 500 mA of DC power. After about 3,000 switching, the contact resistance between the small wafer and the gold-plated contacts of the PCB is significantly increased due to the arc ablation in the presence of the switch (by about 1 ohm.
  • this small wafer coated with tungsten-nickel alloy and PCB gold-plated contacts pass 500 mA DC, after about 20,000 switching, the contact between the small disc and the PCB gold finger Resistance, still below 1 ohm.
  • 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, a larger mesh stainless steel mesh is required to prepare a plated switch contact.

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Abstract

一种含难熔金属合金镀层的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（1），第二层为金属薄片层（2），第三层为难熔金属合金的化学沉积层（3）。本化学沉积所采用的镀液中含可溶性钨化合物和可溶性钼化合物等。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沉积时，难熔金属合金镀层（3）选择性地沉积在金属表面上。该方法制备的开关触点，具有良好的金属色泽，较低的接触电阻，较低的成本，较高的耐开关电话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

一种含难熔金属合金镀层的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)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，将使触点受到氧化和烧蚀，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。
各种纯金属中以钨的熔点最高。熔点高于1850℃的纯金属分别是：钨(熔点3410℃)、铼(熔点3180℃)、锇(熔点3045℃)、钽(熔点2996℃)、钼(熔点2610℃)、铌(熔点2468℃)、铪(熔点2227℃)、钒(熔点1900℃)、铬(熔点1875℃)和锆(熔点1852℃)。难熔金属有较低的蒸气压，在真空高温下有较低的蒸发速率。难熔金属较低的蒸气压和蒸发速率，是我们选择它们的合金作为触点材料的一个考虑因素。
难熔金属合金的制备方法有粉末冶金法、真空电弧熔炼法和真空电子轰击熔炼法等。以粉末冶金法应用最广泛，因为该法工艺简单并能获得晶粒细小的合金坯锭而有利于进一步的塑性加工。粉末冶金法主要工艺是：将难熔金属粉末(例如钨粉和钼粉)依比例进行机械混合；通过机械压机或等静压机压制成原坯；再在通氢的高温烧结炉中烧结成合金坯锭。烧结温度随钨含量的增加而提高，其范围在2150～2300℃之间。最后将烧结坯锭经轧制或锻造成 材。用这些方法制备难熔金属的合金，都需要较为昂贵的设备，所制得的难熔金属合金的形状也是有形状的。采用最广泛使用的粉末冶金法，较难制得厚度较小的难熔金属合金的薄片(特别是钨合金薄片)。如果将较厚的难熔金属合金的薄片，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，而且由于难熔金属合金的硬度大，进行分割或冲切加工困难。
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。虽然镀银的成本比较低，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7169215公开了化学沉积铜钼合金的材料和方法，所得到的不含碱金属离子和碱土金属离子的铜钼合金电阻率低于30微欧姆/厘米。该合金沉积于单个硅晶上、硅热氧化层上、硅衬底上的铜和钴薄膜上。该铜钼合金可用作金属层间的阻隔层和芯片上的互连材料。在这些应用中该铜钼合金虽然可以取代铜，但电阻率比铜高。该发明中公开了对基材用钯溶液活化，然后让铜钼在各种基材上进行化学沉积。该发明不涉及选择性化学沉积。该铜钼合金的耐电弧烧蚀的性能较差，不是理想的耐电弧烧蚀的触点材料。
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，由于在电弧作用下钴基合金很容易产生氧化钴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。
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、耐电弧性不太高的缺陷，或者克服铜基、镍基或不锈钢触点虽然成本较低但耐电弧性较差的缺点，提供一种制造成本低、导通性能好、耐电弧烧蚀的含难熔金属合金镀层的开关触点。
第一技术方案：本发明提供的一种含难熔金属合金镀层的开关触点，开关触点是具有三 层层状结构的层状复合体，如小圆柱粒、棱柱粒或椭圆柱粒，第一层为0.1-10mm厚的疏水性橡胶层，第二层为0.01-1.0mm厚的金属薄片层，第三层为2*10-5-0.02mm厚的难熔金属合金的化学沉积层；其中，第三层难熔金属合金的化学沉积层是第一层和第二层的复合体浸渍在含有至少一种可溶性的难熔金属的化合物的化学镀液中，用化学沉积的方法将难熔金属合金的镀层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；在第三层中或占第三层总厚度三分之一的外表层中，钨、铼、锇、钽、钼、铌、铪、钒、铬、锆的重量百分比之和，不低于50％；在第三层难熔金属合金层中含有重量百分比不超过50％的过渡金属元素铁、镍、钴、铜、锰或这些元素的任意组合、重量百分比不超过10％的锡、锑、铅或铋或这些元素的任意组合。
钨是制备难熔金属合金镀层优先选用的元素，以使镀层获得优良的耐电弧烧蚀性能。在除钨以外的难熔金属元素中，优先选用熔点较高的、化合物毒性较小、市场供应较充足且价格较低的钼元素，与钨形成难熔金属的合金，也就是钨钼合金，或钼钨合金。此外，可以使镀层中含有铼、锇、钽、钼、铌、铪、钒、铬或锆等难熔金属元素。在制备难熔金属合金时，可以使用一种或一种以上的化学镀液，使得在难熔金属的镀层中，钨元素或其它难熔金属元素的百分含量随镀层厚度而呈阶梯式的变化。在难熔金属合金镀层的外表面中，含有重量百分比不低于50％的难熔金属元素，以保证镀层具有良好的耐电弧烧蚀性能。
钨钼合金可以在比纯钼或钼合金更高的温度下使用。如在生产高熔点耐火陶瓷纤维的波歇炉中以钼钨合金作电极、流口及顶针部件时，其使用寿命比纯金属钼制品要长得多。钼钨合金由于熔点高、抗烧蚀性能和抗固体粒子的火焰冲蚀性好，也可用于固体火箭发动机的燃气舵和护板等部件。钨钼合金综合了钨的一些优点和钼的一些优点。因此，该合金可以在钼与钨之间的广阔温度范围内得到应用。这些因素，也是本发明中优先采用钨钼合金作为触点材料的原因。采用该合金作为触点材料，可在一定程度上，将钨的优良的耐电弧烧蚀性能和钼的易加工性能，综合在一起。
在难熔金属合金的镀液中加入铁、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度。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，将是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。
所述第一层为0.1-10mm厚的疏水性橡胶层。疏水性橡胶层由疏水性橡胶制成的。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。为了获得难熔金属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。在用前述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°。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，将使难熔金属的合金也沉积在这些橡胶材料上。一般来说，所用橡胶材料的疏水性越强，越有利于难熔金属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进行选择性化学沉积，而不在橡胶材料的表面上沉积。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，表面疏水性不强。这些材料在含可溶性难熔金属的化合物的化学镀液中，难熔金属的镀层就会沉积在这些材料的表面。
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。橡胶材料是热固性的或热塑性的。
作为进一步的优化：所述的疏水性橡胶层由三元乙丙橡胶、甲基乙烯基硅橡胶或甲基乙烯基苯基硅橡胶制备而成。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，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。因此，它们是所述的疏水性橡胶层的优先使用的材料。
这里所谓的选择性化学沉积，指的是难熔金属合金镀层，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。如果橡胶材质上有难熔金属合金的沉积层，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，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，从而可制备包含触点的橡胶按键。
因此，必需限制上述的这些极性基团在橡胶基材中的含量，以获得选择性化学沉积。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、抗静电剂或表面活性剂，也有利于获得选择性好的化学沉积。
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、锡或金或含有这些元素的合金；第二层的金属薄片是单一金属材质的或不同金属材质层状复合的；优选电导率较高且价格比较低的金属或合金。
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0.1-10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是由真空镀膜、电镀或化学镀的方法制备的。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难熔金属合金镀层的粘合强度，避免难熔金属合金镀层在触点使用过程中脱落。特别是铜和铜合金薄片，宜在化学沉积难熔金属合金镀层之前，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。
上述的不锈钢是普通不锈钢、耐酸钢、或者添加了钨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难熔金属合金镀层，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，分割或冲切加工变得困难，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或热塑性粘合而形成橡胶按键，就会在模塑过程中发生溢胶现象。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：提供上述含难熔金属合金的开关触点的一种制备方法。
第二技术方案：一种含难熔金属合金的开关触点的制备方法，包括如下步骤：
(1)金属薄片层的处理：金属薄片层为0.01-1.0mm厚的不锈钢、铜或铜合金、镍或镍合金薄片，在不锈钢、铜或铜合金、镍或镍合金薄片的一面或两面，或用真空镀膜、电镀或 化学镀的方法镀有0.01-10微米的纯镍层或镍合金层；优先选用化学镀的方法制备镍合金层；
(2)疏水性橡胶层与金属薄片层的粘合处理：疏水性橡胶层通过热硫化成型，粘合在涂有底涂剂或粘合促进剂的金属薄片层上，形成复合片材；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层上，形成复合片材；
(3)切割处理：将上述步骤中的复合片材分割或冲切成直径为2-10mm的圆柱体，用碱性清洗液清洗约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，沥干；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，增强金属基材和难熔金属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)难熔金属合金镀层的制备：将上述圆柱体，浸渍在含有可溶性难熔金属化合物化学镀液中，搅拌，用化学镀的方法形成难熔金属合金镀层；或者，将上述圆柱体放入含有可溶性难熔金属化合物的化学镀液的滚筒中，让滚筒转动，在小圆柱体的金属表面，形成难熔金属合金镀层；
镀液中含有20-150g/L的可溶性钨、铼、锇、钽、钼、铌、铪、钒、铬或锆的化合物或这些化合物的任意组合、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、20-150g/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、0.1-2g/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。氟化钠既可以作为加速剂，同时亦可以增加镀层的光亮度；
当采用次亚磷酸钠作为还原剂时，难熔金属合金镀层所采用化学镀的温度为65-80℃，时间为45-270分钟，镀液的pH值为8.5-9.5。
(5)清洗、干燥：取出后用蒸馏水或去离子水漂洗、沥干、冷风吹干或放在70℃的恒温烘箱中烘干，即得到金属面层镀有难熔金属合金的开关触点。
本发明中，所述的可溶性钨化合物是钨酸钠、钨酸钾、钨酸铵、偏钨酸铵、磷钨酸钠、钨酸、三氧化钨中的一种或多种。选用不溶于纯水的钨酸或三氧化钨作为钨源时，先用氢氧化钠碱溶液使钨酸或三氧化钨溶解，然后用溶解了的钨酸或三氧化钨配置化学镀液。优先选用易于溶解且价格价低的钨酸钠配制化学镀液。所述的可溶性钼化合物是钼酸钠、钼酸钾、钼酸铵、磷钼酸、磷钼酸铵、钼酸、三氧化钼。使用微溶于水的钼酸或不溶于水的三氧化钼作为钼源时，可先用氢氧化钠溶液使其溶解，然后用其配制化学镀液。所述的其它难熔金属的可溶性化合物包括高铼酸钠、高铼酸钾、高铼酸铵、锇酸钾、氢氧化钽或水合五氧化二钽、氟钽酸钾、铌酸钾、水合氧化铌、二氯氧化铪八水合物、六氟铪酸钾、钒酸钠、偏钒酸钠、原钒酸钠、偏钒酸铵、矾酸酐、重铬酸钾、三氧化二铬(使用之前用碱液溶解)、六氟锆酸钾、硝酸氧锆等。
所述的可溶性镍化合物是硫酸镍、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。我们在镀钨钼合金时发现，但化学镀液中镍的前体使用硫酸镍和碱式碳酸镍复配，可使镀得的钨钼合金层具有较明亮的银白色，所得钨钼合金镀层的表面电阻较低。所述的可溶性钴化合物是硫酸钴、氯化钴、硝酸钴、硫酸钴铵、碱式碳酸钴、氨基磺酸钴、乙酸钴、草酸钴中的一种或多种。所述的可溶性铜化合物硫酸铜、氯化铜、硝酸铜、水合碱式碳酸铜、乙酸铜中的一种或多种。
镀液中可加入镍、钴、铜以外的其它可溶性过渡金属元素的化合物，以及可溶性的锡化合物、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，但不建议在钨钼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，在钨钼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了。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。
所述的还原剂为次亚磷酸钠、硼氢化钠、烷基胺硼烷、肼、三氯化钛中的一种或多种。如果以硼氢化物或氨基硼烷为还原剂时，钨钼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，镀层中除有金属元素外还含有少量的磷。磷对触点的导电性是有害的，并且可能伤害难熔金属合金的耐腐蚀性能，因此，必需控制钨钼合金中的磷含量。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、无孔的钨钼合金等难熔金属合金的镀层。本发明中优先价格较低且毒性比较低的次亚磷酸钠。选用次亚磷酸钠作为还原剂，我们所得到的钨钼合金镀层之间的接触电阻，比镍含量为99.5％以上的纯镍和镍含量为99.5％以上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。选用次亚磷酸钠作为还原剂有很好的性价比。为了使镀液中的锡离子或亚锡离子沉积到镀层中，需使用还原性较强的三氯化钛(TiCl3)作还原剂，同时添加某些合适的络合剂如柠檬酸盐或EDTA。
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。
当采用次亚磷酸钠作为还原剂时，镀液的pH值优选为8.5-9.5。由于在化学镀反应过程中，副产物氢离子的产生，导致镀液pH值会下降。使用，在化学镀的过程中，需补充pH调节剂。所述的pH调节剂为氢氧化钠、氢氧化钾、碳酸钠、氨水、焦磷酸钠、醋酸钠、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，镀层质量更好的钨钼合金镀层。氨水或氢氧化钠溶液的价格也比较便宜。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。为了稳定镀速和保证镀层质量，镀液必须具备缓冲能力，使镀液的pH值维持在合适的范围内。因此，镀液中含有强碱弱酸盐作为pH值缓冲剂。
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，使得难熔金属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。
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。
所述的光亮剂或粗糙度调节剂为甲醛、乙醛、枯茗醛、氯苯甲醛、β-萘酚、2-甲基醛缩苯胺、苄叉丙酮、二苯甲酮、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。可同时使用两种或两种以上的光亮剂复配，以增加镀层的光亮效果，减少光亮剂的用量。
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难熔金属合金镀层就会越厚。较厚的难熔金属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。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，所述难熔金属合金镀层所采用化学镀的时间为200分钟。升高化学镀 液的温度，会使得化学沉积的速率加快，但过高的镀液温度(高于90℃)，将使化学镀层的颜色变深、镀层对金属基材的附着力下降。
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，可使难熔金属合金镀层沉积在金属的表面。我们用X射线荧光光谱仪(XRF)检测金属表面的难熔金属元素含量，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难熔金属元素信号越来越强。难熔金属元素信号越来越强，意味着难熔金属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难熔金属元素信号也几乎为零。
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难熔金属的合金，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)制得的镀有难熔金属合金层的触点，与PCB上的镀金触点接触，触点间的接触电阻，比没有镀难熔金属合金的同类触点与PCB上的镀金触点间的接触电阻小，具有较好的导通性能。由没有镀难熔金属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2000-4000次后，由于存在开关时的电弧烧蚀，由这些金属材质制备的触点和PCB镀金触点之间的接触电阻就明显升高(由约1欧姆升高至100欧姆以上，甚至不导通)；而在同样的电路条件下，按本发明镀有钨钼合金的同类触点与PCB镀金触点通过300毫安的直流电，开关约10000次后，触点和PCB触点之间的接触电阻，仍在1欧姆以下。
这种镀难熔金属合金的触点，成本较低。与镀有金或银的开关触点比较，能够通过获承受更大的电流，具有更好的耐电弧烧蚀性能。而且，优先选用的钨、钼材料的价格远低于黄金、铂或银。在这种镀有难熔金属合金镀层的触点，由于可用钼元素代替了部分钨元素，制备所用的原材料成本也较低。
调节镀液的配方组成和化学镀的时间和温度，所得的含有难熔金属合金镀层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。本发明的产品适用于各种对开关使用寿命有严格要求的低压电器，尤其适合于制作汽车、电动工具、游戏机等电器电子设备中，需要接通、承载和分断大于50mA的电流的开关触点。
本发明中制备的触点，含有疏水性的橡胶层。疏水性的橡胶层的表面，没有沉积难熔金属的合金。疏水性橡胶层的存在，便于这种触点与其它橡胶进行热硫化粘合和热硫化成型，从而制成带有触点的橡胶按键产品。
附图说明
图1是本发明的一种剖面结构示意图；
图2是本发明的制备方法中一种工艺流程图。
其中，图中：1、橡胶层；2、金属薄片层；3、难熔金属合金镀层。
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：
制备一种含难熔金属合金镀层的开关触点：
其镀液组成为：
Figure PCTCN2015084169-appb-000001
镀液的配制：先将上述各种化合物用水溶解或用水加热溶解，然后按比例混合在一起。用氨水调pH值至9.0，并加水稀释至规定体积。
工艺路线：
如图1、2所示，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，作为金属薄片层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0.1mm，峰间距为0.2mm。然后用pH值为9左右的碱性清洗液进行清洗除油，水洗，然后用工业酒精进行清洗除油，然后用12.5％的硫酸溶液在50至80℃的温度下清洗2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，用含有硫酸镍和次亚磷酸钠的化学镀镍镀液，镀上厚度约为2.5微米的镍层。金属基材上化学镀镍是一种成熟的工艺，不在此详述。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(德国瓦克公司生产的
Figure PCTCN2015084169-appb-000002
R 401/60)和乙烯基三特丁基过氧硅烷(VTPS)和过氧化二异丙苯(DCP)用开炼机混炼均匀，作为橡胶层1。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(如镍、碳钢、不锈钢、铜等)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℃下进行热硫化粘合何热硫化成型，硫化时间为12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表面，有特氟龙涂层。特氟龙涂层的存在，防止了混炼胶在热硫化过程中粘模。将此复合片材冲切成直径为5mm的小圆片。把这种小圆片用碱性清洗液清洗分钟，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1min，然后清洗，沥干。
将这样的500粒小圆片，放入80℃的上述600mL镀液中，搅拌，200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℃的恒温烘箱中烘干，即得到金属面层镀有钨钼合金即为难熔金属合金镀层3的小圆片。在化学镀的过程中，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。
这种含有硅橡胶层的镀有钨钼合金的小圆片，和硅橡胶进行热硫化粘合和热硫化成型。小圆片中的硅橡胶面和其它硅橡胶热硫化粘合，镀有钨钼合金层的一面朝外，以便钨钼合金层可以和印刷电路板(PCB)上的触点接触。这种小圆片和硅橡胶热硫化成型后，可制成橡胶按键。正是这种小圆片用作了橡胶按键中用作电路开关的触点。该触点与PCB上的镀金触点接触，具有稳定的和较低的接触电阻，而且这种镀有钨钼合金的小圆片有更好的导通稳定性：由没有钨钼合金镀层的锌白铜或镀有镍层的锌白铜制得的小圆片与PCB镀金触点通过300毫安的直流电，开关约3000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1欧姆升高至100欧姆以上，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，这种镀有钨钼合金的小圆片与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1欧姆以下。
实施例2：
制备一种含难熔金属合金镀层的开关触点：
镀液组成：
Figure PCTCN2015084169-appb-000003
Figure PCTCN2015084169-appb-000004
镀液的配制：先将上述各种化合物用水溶解，可加热加快溶解进度。其中三氯化钛可用水或10％的盐酸溶液溶解。配制的三氯化钛溶液不能长时间放置，以免发生沉淀。除三氯化钛溶液和氨水，将上述所有溶液按比例混合形成一混合液；将三氯化铁溶液按比例加入到混合液中，并搅拌均匀；用氨水调pH值至9.0，并加水稀释至规定体积。
工艺路线：
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，并清洗干净，用作金属薄片层2，将其一面用一种橡胶-金属粘合剂(美国罗门哈斯公司生产的Megum 14135)进行底涂处理，然后，将底涂处理过的这一面，和一种甲基乙烯基苯基硅橡胶(德国瓦克公司生产的Elastosil R 401/60)进行热硫化粘合，作橡胶层1，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的小圆片。
把这种小圆片用碱性清洗液清洗约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1000mL镀液小型滚筒中中，自动，240分钟后取出，用蒸馏水或去离子水漂洗、沥干、冷风吹干，即得等到金属面层镀有钨钼钴锡合金即为难熔金属合金镀层3的小圆片。在化学镀的过程中，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。钨钼钴锡合金只在小圆片中的不锈钢表面沉积，不在小圆片中的硅橡胶表面沉积。在镀液中，加入了硫酸钴而不是加入了硫酸镍。在化学镀过程中，钴离子的析出比镍离子的析出稍慢，这样就既可利用 钴元素的存在到达镀层与不锈钢基材粘合良好的目的，又可以减少镀层中具有较低熔点的过渡金属的含量。镀液中加入氯化亚锡的目的，是为了使镀层中含有锡元素而得到较软的化学沉积层。较软的化学沉积层，如作为一触点的外表面，将与对与之接触的另一触点(如PCB上的镀金的触点)形成更紧密的接触，并可减少对与之接触的另一触点的磨损。
这种镀有钨钼钴锡合金的小圆片，和硅橡胶热硫化粘合(小圆片中的硅橡胶面和其它硅橡胶热硫化粘合，镀有钨钼钴锡合金的一面朝外)，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，触点的接触电阻比直接由不锈钢片制得的小圆片与PCB的镀金触点之间的接触电阻低，而且这种镀有钨钼钴锡合金的小圆片有更好的导通稳定性：由没有钨钼钴锡合金镀层的不锈钢制得的小圆片与PCB镀金触点通过500毫安的直流电，开关约3000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1欧姆升高至100欧姆以上，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，这种镀有钨镍合金的小圆片与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金手指之间的接触电阻，仍在1欧姆以下。
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，需采用较大目数的不锈钢网来制备有镀层的开关触点。
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. 一种含难熔金属合金镀层的开关触点，其特征在于：开关触点是具有三层层状结构的层状复合体；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厚的难熔金属合金的化学沉积层；其中，第三层难熔金属合金的化学沉积层是第一层和第二层的复合体浸渍在含有至少一种可溶性的难熔金属的化合物的化学镀液中，用化学沉积的方法将难熔金属合金的镀层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；在第三层难熔金属合金层中或占第三层总厚度三分之一的外表层中，钨、铼、锇、钽、钼、铌、铪、钒、铬、锆的重量百分比之和，不低于50％；在第三层难熔金属合金层中含有重量百分比不超过50％的过渡金属元素铁、镍、钴、铜、锰或这些元素的任意组合、重量百分比不超过10％的锡、锑、铅或铋或这些元素的任意组合。
  2. 根据权利要求1所述的含难熔金属合金镀层的开关触点，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所述的含难熔金属合金镀层的开关触点，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或3所述的含难熔金属合金镀层的开关触点，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、锡或金或含有这些元素的合金；所述的金属薄片是单一金属材质的或不同金属材质层状复合的。
  5. 根据权利要求1或4所述的含难熔金属合金镀层的开关触点，其特征在于：所述的金属薄片层的金属薄片由0.01mm至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微米至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、纯钴层或钴合金层是由真空镀膜、电镀或化学镀的方法制备的。
  6. 一种含难熔金属合金镀层的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)金属薄片层的处理：金属薄片层为0.01mm至1.0mm厚的不锈钢、铜或铜合金、镍或镍合金薄片，在不锈钢、铜或铜合金、镍或镍合金薄片的一面或两面，用真空镀膜、电镀或化学镀的方法镀有0.05微米至10微米的纯镍层或镍合金层、纯钴层或钴合金层；
    (2)疏水性橡胶层与金属薄片层的粘合处理：疏水性橡胶层通过热硫化成型，粘合在涂 有底涂剂或粘合促进剂的金属薄片层上，形成复合片材；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层上，形成复合片材；
    (3)切割处理：将上述步骤中的复合片材分割或冲切成包括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、星形或者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，然后用5％的盐酸清洗3分钟，然后用去离子水清洗干净，沥干；
    (4)难熔金属合金镀层的制备：将上述圆柱体或物体，浸渍在含有可溶性钨化合物和可溶性的其它难熔金属化合物的化学镀液，搅拌，用化学镀的方法在圆柱体或物体的金属表面形成难熔金属合金镀层；或者，将上述圆柱体放入含有可溶性钨化合物和可溶性的其它难熔金属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或物体的金属表面，形成难熔金属合金镀层；
    镀液中含有20-150g/L的可溶性的钨、铼、锇、钽、钼、铌、铪、钒、铬或锆的化合物或这些化合物的任意组合、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、20-150g/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、0.1-2g/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，难熔金属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、干燥：取出上述被镀物，用蒸馏水或去离子水漂洗、沥干、冷风吹干或放在70℃的恒温烘箱中烘干，即得到金属面层镀有难熔金属合金的开关触点。
  7. 根据权利要求6所述的含难熔金属合金镀层的开关触点的制备方法，其特征在于：作为优选，所述的含难熔金属合金镀层所采用化学镀的时间为100-200分钟；镀液的温度为70-80℃；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。
  8. 根据权利要求6所述的含难熔金属合金镀层的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。
  9. 根据权利要求6所述的含难熔金属合金镀层的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，优先选用价格低的次亚磷酸钠。
  10. 根据权利要求6所述的含难熔金属合金镀层的开关触点的制备方法，其特征在于：所述的光亮剂或粗糙度调节剂为甲醛、乙醛、枯茗醛、氯苯甲醛、β-萘酚、2-甲基醛缩苯胺、苄 叉丙酮、二苯甲酮、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。
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CN108950610B (zh) * 2018-08-27 2021-01-01 重庆立道新材料科技有限公司 一种三价铬镀铬层增白剂及其镀铬电镀液
CN110541150B (zh) * 2019-08-22 2024-05-03 沈阳科友真空技术有限公司 一种干簧管继电器触点用多层膜结构及其制备方法
CN113122830A (zh) * 2021-04-25 2021-07-16 哈尔滨科友半导体产业装备与技术研究院有限公司 一种钨片或钨坩埚表面镀钽膜层及其制备方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6436816B1 (en) * 1998-07-31 2002-08-20 Industrial Technology Research Institute Method of electroless plating copper on nitride barrier
CN101809695A (zh) * 2007-09-26 2010-08-18 古河电气工业株式会社 可动触点用银包覆复合材料及其制造方法
JP2012107263A (ja) * 2010-11-15 2012-06-07 Kyowa Densen Kk メッキ構造及び被覆方法
CN104112608A (zh) * 2014-07-21 2014-10-22 南通万德科技有限公司 一种含难熔金属合金镀层的开关触点及其制备方法

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9263609B2 (en) * 2006-05-24 2016-02-16 Atotech Deutschland Gmbh Metal plating composition and method for the deposition of copper—zinc—tin suitable for manufacturing thin film solar cell

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6436816B1 (en) * 1998-07-31 2002-08-20 Industrial Technology Research Institute Method of electroless plating copper on nitride barrier
CN101809695A (zh) * 2007-09-26 2010-08-18 古河电气工业株式会社 可动触点用银包覆复合材料及其制造方法
JP2012107263A (ja) * 2010-11-15 2012-06-07 Kyowa Densen Kk メッキ構造及び被覆方法
CN104112608A (zh) * 2014-07-21 2014-10-22 南通万德科技有限公司 一种含难熔金属合金镀层的开关触点及其制备方法

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111020540A (zh) * 2019-12-05 2020-04-17 光山白鲨针布有限公司 一种中磷化学镀镍液及应用
CN111020540B (zh) * 2019-12-05 2022-04-01 光山白鲨针布有限公司 一种中磷化学镀镍液及应用
CN115116742A (zh) * 2022-08-23 2022-09-27 苏州聚生精密冲件有限公司 一种控制电容电阻及免焊锡铜导电片的电容制作工艺

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