WO2016011914A1 - 一种镀金的开关触点及其制备方法 - Google Patents

一种镀金的开关触点及其制备方法 Download PDF

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Publication number
WO2016011914A1
WO2016011914A1 PCT/CN2015/084170 CN2015084170W WO2016011914A1 WO 2016011914 A1 WO2016011914 A1 WO 2016011914A1 CN 2015084170 W CN2015084170 W CN 2015084170W WO 2016011914 A1 WO2016011914 A1 WO 2016011914A1
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Prior art keywords
layer
gold
rubber
metal
nickel
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PCT/CN2015/084170
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English (en)
French (fr)
Inventor
韩辉升
王振兴
张红梅
丁阳
邬国强
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南通万德科技有限公司
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Publication of WO2016011914A1 publication Critical patent/WO2016011914A1/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

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 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.
  • the surface of the contact may be plated with gold or silver.
  • Gold's chemical stability and atmospheric corrosion resistance are better than silver, and its electrical conductivity is similar to that of silver, so the contact gold plating is used in high-end applications.
  • the switch is turned on or off in addition to problems such as arc ablation, adhesion, and oxidation, as well as contact jitter.
  • Contact jitter refers to the continuous runout of the switch when the closed contact is closed or the closed contact is closed.
  • the jitter time can be longer than 20 milliseconds. This type of jitter can cause the switch to "batter" response, which can lead to various accidents.
  • 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. Although the conductivity and heat transfer properties of silver are the highest among all metals, 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.
  • H 2 S hydrogen sulfide
  • the document of the patent application number 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 gold plating layer disclosed in this document is plated by conventional plating or vacuum sputtering.
  • U.S. Patent No. 7,011,697 discloses an electroless gold plating solution comprising cyanide and ascorbic acid or a derivative thereof, and further comprising one or more deposition accelerators selected from the group consisting of copper compounds, antimony compounds and lead compounds.
  • U.S. Patent No. 5,164,004 discloses the addition of 0.1-10 g/L of a chelating agent such as diethylenetriaminetetraacetic acid, ethylenediaminetetraacetic acid or aminotriacetic acid to an electroless gold plating solution under conditions of high concentration of antimony or lead compounds. Gold precipitation does not occur in the gold plating solution, and the deposition rate of the plating solution is fast, and the crystal grains in the deposition layer are large.
  • U.S. Patent 5,560,764 discloses an electroless gold plating solution containing an alkali metal gold cyanide, a boron based reducing agent, an alkali metal hydroxide and 2-20 g/L of dimethylamine.
  • concentration of dimethylamine is less than 2g/L, the deposition rate of gold will decrease; the concentration of dimethylamine higher than 20g/L will accelerate the decomposition of the plating solution.
  • the gold of the gold plating solution is deposited on a predetermined area of the surface of the workpiece.
  • the control electroless gold plating solution containing triethanolamine will deposit a gold layer in the metallized and non-metallized regions, so that two adjacent metallized regions become electrically connected.
  • European Patent Application EP0702099 controls the deposition of an electroless gold plating layer to a predetermined area by adding 5-500 mg/L of sodium nitrobenzenesulfonate and/or p-nitrobenzoic acid as a reduction inhibitor.
  • U.S. Patent No. 5,803,957 discloses an electroless gold plating solution which deposits a gold layer on a metal portion of a non-conductive substrate by a small amount of polyvinylpyrrolidone contained in the gold plating solution. It can be seen that selective deposition of electroless gold plating can be controlled and achieved by adding certain special compounds to the electroless gold plating solution.
  • 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, aluminum or nickel; the rubber base is silicone rubber or urethane rubber; the metal surface layer and the rubber base can have a bonding layer, and the bonding
  • the layer is a hot vulcanizate, a 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, oxidation problems and contact jitter of conductive particles.
  • the invention does not teach a specific method of how to obtain one or more plating layers on the outer surface of the metal facing layer, nor does it teach how to selectively deposit the metal plating layer on the surface of the metal without depositing it on the rubber.
  • the first object of the invention is to overcome the disadvantages of copper-based, silver-based, nickel-based or stainless steel contacts, although the cost is low, the arc resistance is poor, the chemical stability is poor, and the contact jitter time is long, providing a conduction performance.
  • a first technical solution: a gold-plated switch contact disclosed in the present invention is a layered composite body having a three-layered layer structure. Such as small cylindrical particles, prismatic particles or elliptical column particles.
  • the first layer is a 0.1 mm to 10 mm thick hydrophobic rubber layer
  • the second layer is 0.01 mm to 1.0 mm thick containing magnesium, aluminum, titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, bismuth, molybdenum.
  • the third layer being a gold plating layer of 0.01-2.0 micron thick; wherein the third gold plating layer is a composite of the first layer and the second layer impregnated with a soluble gold compound
  • gold or a gold alloy is deposited by chemical deposition on the surface of the second layer in the composite of the first layer and the second layer.
  • the above electroless plating solution may further contain a soluble small amount of a compound of lead, antimony, tin, antimony or tungsten.
  • a compound of lead, antimony, tin, antimony or tungsten as accelerators for electroless gold plating, function to increase the rate of formation of the coating while preserving the quality of the coating.
  • the hydrophobic rubber layer of the gold-plated switch contact of the present invention is due to the low content of carboxyl, hydroxyl, carbonyl, amino, amido, nitrile, nitro, halo, sulfonyl, sulfonate and benzenesulfonate groups in the rubber molecular chain. Therefore, the rubber surface of the rubber surface is composed of a rubber material having a water contact angle of more than 65°; or the hydrophobic rubber layer is due to the rubber containing no or a small amount of hydrophilic filler or additive, thereby making the surface of the rubber water It is composed of a rubber material having a contact angle of more than 65°.
  • some patent documents disclose the selective deposition of electroless gold plating by adding certain specific compounds to the electroless gold plating solution.
  • the present invention achieves selective chemical deposition of a gold plating layer on a metal by controlling the hydrophobicity of the rubber layer in the rubber and metal layered composite. Hydrophobic rubber has a repulsive ability to water, and water cannot spread on the surface of 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 metal foil the better.
  • the water contact angle of the rubber substrate needs to be greater than 65°.
  • 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. It is therefore necessary to control the content of these groups in the rubber.
  • the hydrophobic rubber layer is prepared from a non-polar or weakly polar rubber.
  • 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, which are highly hydrophobic, and they have good weather resistance and can maintain good elasticity in the atmosphere for a long time. Therefore, they Is the superiority of the hydrophobic rubber layer First choice of materials.
  • the metal foil layer is a metal sheet having bumps or pits, a metal sheet having convex or concave lines, a metal sheet having convex or concave surfaces, and a metal sheet having small holes having an area of less than 1 mm 2 .
  • Metal mesh, metal foam or metal fiber sintered felt; metal materials are magnesium, aluminum, titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, antimony, molybdenum, silver, tin, antimony, tungsten or contain these elements
  • the metal foil is a single metal material or a layered composite of different metal materials.
  • the material of the metal foil layer is preferably a metal or alloy having a good chemical stability, a high electrical conductivity, and a relatively low price.
  • the foil of the metal foil layer is composed 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. Or a pure nickel or nickel alloy layer of 0.01-10 micron, a pure cobalt layer or a cobalt alloy layer; a pure nickel layer or a nickel alloy layer on a stainless steel, copper or copper alloy, nickel or nickel alloy sheet, a pure cobalt layer Or the cobalt alloy layer is prepared by vacuum coating, electroplating or electroless plating.
  • the second layer of metal foil is composed 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 gold plating layer, and prevent the gold plating layer from falling off during the use of the contact.
  • 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.
  • the stainless steel selected is ordinary stainless steel, acid-resistant steel, or added with tungsten and molybdenum 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 gold plating layer may not be well supported, and is easily broken during processing before, during or after the rubber compounding. 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.
  • the second object of the invention is to introduce the gold plating layer and the rubber layer into a contact at the same time, so that the contact integrates the advantages of rubber and gold, has low electrical resistance, good chemical stability, good atmospheric corrosion resistance and arc ablation resistance. Good, good resistance to contact jitter, etc. characteristic.
  • the present invention provides a method for preparing a gold-plated switch contact having a rubber layer and having excellent conduction performance, arc erosion resistance, and contact resistance.
  • the method for preparing a gold-plated switch contact disclosed in the present invention comprises 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 a pure nickel layer or a nickel alloy layer, a pure cobalt layer or a cobalt alloy layer to 10 micrometers; then the degreased and cleaned metal foil obtained by using a cleaning agent and an organic solvent;
  • the hydrophobic rubber layer 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 layer.
  • the electroless plating solution contains 1-15 g/L of soluble gold compound, 5-100 g/L of complexing agent, 1-10 g/L of stabilizer, 5-100 g/L of reducing agent, and stability of 0-50 g/L.
  • Agent 2-50g/L pH adjuster, 0.5mg/L-5g/L accelerator;
  • the soluble gold compound is potassium gold cyanide, potassium gold cyanide, gold potassium citrate, gold trichloride, chloroauric acid and its salt, potassium gold chloride and gold sodium sulfite;
  • the complexing agent is a water-soluble compound containing a hydroxyl group, a carboxyl group or an amino group, and potassium cyanide, and includes sodium citrate, potassium citrate, sodium tartrate, sodium salt of EDTA, and the like.
  • the stabilizer is ascorbic acid, sodium ascorbate, 1,2-diaminoethane, thiol, thiourea, methylthiourea or the like.
  • the reducing agent is formaldehyde, sodium phosphite, sodium borohydride, potassium borohydride, dimethylborane, a derivative of ruthenium or osmium, thiosulfate, sulfite, ascorbic acid and the like.
  • Ascorbic acid can be used as a stabilizer for the plating solution as well as a certain degree of reducibility.
  • the pH adjusting agent is potassium hydroxide, sodium hydroxide, ammonia water, inorganic acid (such as hydrochloric acid) or organic acid (such as lactic acid), strong acid weak base salt (such as ammonium sulfate) or strong base weak acid salt (such as sodium acetate). ).
  • the promoter is a divalent lead compound, a monovalent ruthenium compound, a tetravalent tin compound, and a trivalent ruthenium compound. Or a hexavalent tungsten compound.
  • the role of the accelerator is to increase the rate of formation of the coating while maintaining the quality of the coating.
  • the hexavalent tungsten compound sodium tungstate, potassium tungstate, ammonium tungstate, tungsten hexachloride. Sodium tungstate having low toxicity, good water solubility and low price is preferred.
  • the electroless plating temperature is controlled between 50-95 ° C to ensure a certain reaction speed. Below 50 ° C, the precipitation rate of gold is quite slow; above 95 ° C, the plating solution is unstable and may decompose.
  • the electroless plating time is controlled between 15 minutes and 2 hours to ensure the thickness of the gold plating layer.
  • the thickness of the gold plating layer is 0.3 ⁇ m or more, and when the switching current is 150 mA, the number of times of contact opening and closing reaches 20,000 times or more.
  • the electroless gold plating solution used is cyanide-containing or cyanide-free.
  • the composition of a cyanide-containing electroless gold plating solution is:
  • a small amount of cobalt chloride or nickel chloride may also be added to the plating solution.
  • Excessive metal cobalt and nickel can form a cyanide gold, cobalt and potassium complex in the plating solution, which can improve the brightness and hardness of the coating.
  • the purpose of adding sodium tungstate to the plating solution is to increase the deposition rate of the plating layer to a certain extent without affecting the quality of the gold plating layer (reflected to reach the specified switch life in a short gold plating deposition time). And the phenomenon that the gold plating layer overflows does not occur, and the adhesion of the gold plating layer to the metal substrate is also good.
  • Gold-plated, copper-based or nickel-based contacts are gold plated with an electroless gold plating solution containing sodium tungstate to obtain gold-plated contacts compared to gold-plated contacts obtained with an electroless gold plating solution without the addition of sodium tungstate. Both have better resistance to contact jitter, but the former has better arc ablation resistance, which means that the former has a better service life.
  • tungsten may be deposited in the gold plating layer during electroless plating. Elemental analysis of the coating by X-ray fluorescence spectroscopy (XRF) showed that the gold signal in the coating was strong and the tungsten signal was weak or almost zero. On the surface of the hydrophobic rubber in the object to be plated, neither the signal of tungsten nor the signal of gold was detected. This means that chemical deposition only occurs on the surface of the metal in the object to be plated.
  • XRF X-ray fluorescence spectroscopy
  • the invention selectively coats a layer of gold on the layered composite containing the hydrophobic rubber layer and the metal foil by electroless plating, and the obtained gold-plated product is used as a switch contact, and has good resistance to contact jitter. And anti-arc ablation performance, which can improve the reliability and service life of the contacts. Since the contacts contain a hydrophobic rubber layer, the contacts are suitable for thermal vulcanization bonding and thermal vulcanization molding with other rubbers to produce rubber button products with contacts. In addition, this gold-plated touch The contact resistance of the point is low, the atmospheric corrosion resistance is good, the storage time and the service life are long, and it is suitable for the contact of the rubber button in the high-end occasions such as automobiles.
  • Figure 1 is a schematic cross-sectional view of the present invention; Figure 1: 1, rubber layer; 2, metal foil layer; 3, gold plating layer.
  • the product has a three-layer structure: a rubber layer 1, a metal foil layer 2, a gold plating layer 3, and a zinc white copper sheet having a thickness of 0.1 mm, an HV hardness of 120 to 180, and a copper content of about 55%.
  • Metal substrate 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 hydroperoxide
  • DCP dicumyl peroxide
  • VTPS is a coupling agent containing a peroxy compound that crosslinks vinyl-containing silicone rubber and promotes vinyl-containing silicone rubber and metals (such as nickel, carbon steel, stainless steel, copper, etc.). The bond between.
  • 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 12 minutes.
  • a layered composite sheet of 1.0 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 round particles having a diameter of 5 mm.
  • the small round particles were washed with an alkaline washing solution for a minute, washed with water, then immersed in 5% hydrochloric acid for 3 minutes, and finally activated in 10% dilute sulfuric acid for about 1 minute, then washed and drained.
  • the plating solution is now available.
  • the configuration of the bath and the implementation of electroless gold plating should be carried out under good ventilation and safety protection to avoid operator poisoning.
  • the gold-plated small round particles containing a silicone rubber layer are subjected to thermal vulcanization bonding and thermal vulcanization molding with silicone rubber.
  • the silicone rubber surface of the small round particles is thermally vulcanized and bonded with other silicone rubber, and the gold plating layer is facing outward so that the gold plating layer can be combined with other contacts.
  • Gold-plated contacts on a printed circuit board (PCB) are in contact. After the small round pellets and silicone rubber are heat vulcanized, a rubber button with contacts is formed (this kind of small round pellet is used as a contact in the rubber button).
  • the contact is in contact with the gold-plated contacts on the PCB, with stable and low contact resistance, good arc erosion resistance and contact-jitter resistance: zinc-plated copper or nickel-plated zinc without gold plating
  • the small round particles made of white copper and the gold-plated contacts of the PCB pass 300 mA of direct current. After about 3,000 switching, the contact resistance between the small round particles and the gold-plated contacts of the PCB rises sharply due to arc ablation during switching.
  • this gold-plated contact and PCB gold-plated contacts pass 300 mA of direct current, after about 8000 switching, the contact resistance between this contact and the gold-plated contacts of the PCB is still below 1 ohm, and the contact jitter time after gold plating is also 5- when there is no gold plating. 25 milliseconds, down to less than 2 milliseconds.
  • the metal foil substrate used was the same as in Example 1.
  • a clean fine corrugated zinc white copper sheet was directly laminated with silicone rubber into a 1.0 mm thick sheet, and then the sheet was die cut into small round particles having a diameter of 3.0 mm.
  • the small round particles were plated with a layer of 2.5 ⁇ m thick nickel, and then the above-mentioned nickel-plated small round particles were plated with gold in the same manner as in Example 1.
  • the prepared gold-plated particles, as the contacts of the rubber button, have better arc erosion resistance and contact resistance.
  • the small round particles before gold plating were the same as in Example 1.
  • the electroless gold plating solution is cyanide-free, and its chemical composition is: potassium chloride potassium 2.0g/L, EDTA disodium 20g/L, potassium citrate 5.0g/L, sodium lactate 5.0g/L, thiosulfuric acid Sodium 15g / L, sodium sulfite 15g / L, thiourea 20g / L, sodium tungstate 0.2g / L.
  • Ammonia water is added in an appropriate amount, and the pH is adjusted to 8.5-9.5 with ammonia water.
  • the bath temperature was 60 °C.
  • the electroless plating time was 45 minutes.
  • the contacts thus obtained also have good arc erosion resistance and contact resistance.
  • the 400-mesh stainless steel plain mesh (stainless steel 304) was used instead of the fine corrugated zinc-copper sheet in Example 1, and then the same electroless plating solution and process were used to prepare the arc-resistant ablation performance and the anti-contact. Gold-plated switch contacts with good jitter performance.

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Abstract

本发明公开了一种镀金的开关触点及其制备方法，开关触点是具有三层层状结构的复合体，第一层为疏水性橡胶层，第二层为金属薄片层，第三层镀金层是第一层和第二层的复合体浸渍在含有可溶性金化合物化学镀镀液中，用化学沉积的方法将金或金合金选择性沉积地在复合体中金属薄片的表面而形成的。本发明所制备的开关触点，适于与橡胶进行热硫化粘合和成型，从而制成含有开关触点的橡胶按键。本发明所制备的开关触点，具有耐大气蚀腐性能好、表面接触电阻低、抗触点抖动性能好、耐电弧烧蚀性能好、使用寿命长等优点。

Description

一种镀金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。
为了抵抗开关接通或断开时产生的电弧烧蚀、粘连和氧化，在触点的表面可镀金或镀银。金的化学稳定性和耐大气腐蚀性能比银好，而导电性能与银相近，所以触点镀金应用于高端场合。
开关在接通或断开除了电弧烧蚀、粘连和氧化等问题，还有触点抖动的问题。触点抖动，是指开关在闭合触点的断开或断开触点的闭合时产生的持续跳动现象，抖动时间可长大20毫秒以上。这种抖动，轻者会造成开关“连击”响应，严重的会导致各种事故。
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。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。该文件所公开的的镀金层通过常规电镀或真空溅射的方式镀覆上去的。
美国专利7011697公开了一种化学镀金液，镀金液中包括氰化物和抗坏血酸或其衍生物，还包括一种或多种选自铜化合物、铊化合物和铅化合物的沉积加速剂。美国专利5614004公开了在化学镀金液中加入0.1-10g/L的螯合剂如二乙烯三胺四乙酸、乙二胺四乙酸或氨基三乙酸等，在高浓度的铊或铅化合物的条件下，镀金液中也不发生金的沉淀，同时镀液的沉积速度快，沉积层中晶粒较大。
美国专利5560764公开了一种化学镀金液，该镀金液含有碱金属金的氰化物、硼基还原剂、碱金属的氢氧化物和2-20g/L的二甲胺。二甲胺的浓度低于2g/L，金的沉积速率将降低；浓度高于20g/L的二甲胺则加速镀液的分解。该镀金液的金沉积在工件表面的预定区域上。而对照的含有三乙醇胺的化学镀金液，将在金属化区域和非金属化区域沉积金层，使两个相邻的金属化区域变得电联通起来。欧洲专利申请EP0702099则是通过添加5-500mg/L的硝基苯磺酸钠和/或对硝基苯甲酸作为还原抑制剂来控制化学镀金层沉积到预定区域。美国专利5803957公开了一种化学镀金液，则是通过该镀金液中含有的少量的聚乙烯吡咯烷酮，使得金层沉积在非导电性的基材上的的金属部位。由此可见，通过在化学镀金液中加入某些特殊的化合物，可以控制和实现化学镀金的选择性沉积。
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、铝或镍等；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、氧化问题和触点抖动问题提出解决方案。该发明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，也没有说明如何让金属镀层如何选择性的沉积在金属的表面上而不沉积在橡胶的方法。
发明内容
第一发明目的：克服铜基、银基、镍基或不锈钢触点虽然成本较低但耐电弧性较差、化学稳定性较差、触点抖动时间较长的缺点，提供一种导通性能好、耐电弧烧蚀性能好、触点抖动时间短的镀金的开关触点。
第一技术方案：本发明公开的一种镀金的开关触点，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0.1mm至10mm厚的疏水性橡胶层，第二层为0.01mm至1.0mm厚的含镁、铝、钛、铬、锰、铁、钴、镍、铜、锌、铌、钼、银、锡、钽或钨的金属薄片层，第三层为0.01-2.0微米厚镀金层；其中，第三层镀金层是第一层和第二层的复合体浸渍在含有可溶性的金化合物的化学镀液中，用化学沉积的方法将金或金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。
在上述化学镀液中，还可以含有可溶性的少量铅、铊、锡、锑或钨的化合物。这些化合物，作为化学镀金的促进剂，其作用是在保证镀层质量的前提下，提高镀层的生成速率。
本发明中镀金的开关触点的疏水性橡胶层，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。
前已述及，一些专利文件公开了通过在化学镀金液中加入某些特殊的化合物，实现化学镀金的选择性沉积。本发明是通过控制橡胶和金属层状复合体中橡胶层的疏水性，来实现镀金层在金属上选择性化学沉积。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。为了实现金的的选择性化学沉积，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。为了使沉积在第一层疏水性橡胶层上的金少得可以忽略不计，橡胶基材的水接触角需大于65°。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。因此必须控制橡胶中这些基团的含量。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)、水膨胀橡胶、含有大量亲水性或吸水性填料的橡胶材料、含有表面活性剂或抗静电剂的橡胶材料等材料的极性大、或材料表面的极性大，不宜在本发明中开关触点中使用。如果使用这样的橡胶材料，在进行化学镀金时，将使金也或多或少地沉积在这些橡胶材料上。如果橡胶材料上有金的沉积层，将不仅浪费宝贵的化学镀金的镀液，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。
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。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，因此，它们是所述的疏水性橡胶层的优 先选用的材料。
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、钽、钨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。金属薄片层的材质优选化学稳定性较好、电导率较高且价格比较低的金属或合金。
作为优化，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，或镀有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、纯钴层或钴合金层是由真空镀膜、电镀或化学镀的方法制备的。
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镀金层的粘合强度，避免镀金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，同时阻隔金原子向铜基基材、铜原子向镀金层的迁移。所选用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镀金层，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：将镀金层和橡胶层同时引入到一种触点中，使触点综合橡胶和金的优点，具有电阻低、化学稳定性好、耐大气腐蚀性能好、耐电弧烧蚀性能好、抗触点抖动性能好等 特性。
第二技术方案：本发明提供一种含有橡胶层的具有导通性能、耐电弧烧蚀性能、抗触点抖动性能好的镀金的开关触点的制备方法。
本发明的公开的一种镀金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、纯钴层或钴合金层；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：疏水性橡胶层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；或者将具有自粘性的疏水性橡胶，通过热硫化粘合和热硫化成型，粘合在涂覆有底涂剂或没有涂覆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％的盐酸清洗约2分钟，然后用去离子水清洗干净，沥干；
(4)镀金层的制备：将上述圆柱体或物体，浸渍在含有可溶性金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镀金层；或者，将上述圆柱体放入含有可溶性金化合物的化学镀液的滚筒中，让滚筒转动，用化学镀的方法在上述圆柱体或物体的金属表面，形成镀金层；
化学镀液中含有1-15g/L的可溶性金化合物、5-100g/L的络合剂、1-10g/L的稳定剂、5-100g/L的还原剂、0-50g/L的稳定剂、2-50g/L的pH调节剂、0.5mg/L-5g/L的促进剂；
所述的可溶性金化合物是氰化金钾、氰化亚金钾、柠檬酸金钾、三氯化金、氯金酸及其盐、氯化金钾和亚硫酸金钠；
所述的络合剂是含有羟基、羧基、氨基的水溶性化合物和氰化钾，包括柠檬酸钠、柠檬酸钾、酒石酸钠、EDTA的钠盐等。
所述的稳定剂为抗坏血酸、抗坏血酸钠、1,2-联氨基乙烷、硫醇、硫脲、甲基硫脲等。
所述的还原剂为甲醛、亚磷酸钠、硼氢化钠、硼氢化钾、二甲基硼烷、肼或肼的衍生物、硫代硫酸盐、亚硫酸盐、抗坏血酸等。抗坏血酸既可以作为镀液的稳定剂，也具有一定的还原性。
所述的pH调节剂是氢氧化钾、氢氧化钠、氨水、无机酸(如盐酸)或有机酸(如乳酸)、强酸弱碱盐(如硫酸铵)或强碱弱酸盐(如醋酸钠)。
所述的促进剂是二价的铅化合物、一价的铊化合物、四价的锡化合物、三价的锑化合物 或六价的钨化合物。促进剂的作用是在保证镀层质量的前提下，提高镀层的生成速率。所述的六价的钨化合物钨酸钠、钨酸钾、钨酸氨、六氯化钨。优选毒性低、水溶性好、价格较低的钨酸钠。
化学镀温度控制在50-95℃之间，以保证一定的反应速度。低于50℃,金的析出速度相当慢；高于95℃,镀液不稳定而可能分解。
化学镀的时间控制15分钟到2小时之间，以保证镀金层的厚度。通常镀金层的厚度在0.3μm以上，可以开关工作电流为150mA时，触点通断次数达到20000次以上。
(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，即得到上述被镀物的金属表面上镀有金层的开关触点。
本发明中，所使用的化学镀金液是含氰的，或不含氰的。一个含氰的化学镀金液的组成为：
Figure PCTCN2015084170-appb-000001
镀液中还可加入少量的氯化钴或或氯化镍。过度金属钴和镍在镀液中可形成氰化亚金钴钾复合物，可以提高镀层光亮度和硬度。镀液中加入钨酸钠的目的是为了在不影响镀金层的质量的情况下，使镀层沉积速度得到一定程度的提高(反映在在较短的镀金沉积时间内可到达规定的开关使用寿命)，并且不发生镀金层溢出的现象，镀金层对金属基材的附着性也好。用加入钨酸钠的化学镀金液，对不锈钢基、铜基或镍基触点进行镀金，所得到的镀金触点，与用没有加入钨酸钠的化学镀金液所得到的镀金触点相比，两者都有较好的抗触点抖动性能，但前者的耐电弧烧蚀性能更好，这意味着前者的使用寿命更好。
镀液中加入钨酸钠后，极少量的钨元素可能会在化学镀时沉积在镀金层中。用X射线荧光光谱分析(XRF)对镀层进行元素分析，可以看到镀层中金的信号很强，钨的信号很弱或几乎为零。在被镀物中的疏水性橡胶的表面上，则既检测不到钨的信号，也检测不到金的信号。这说明化学沉积只发生在被镀物中的金属的表面上。
有益效果：
本发明在含有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金，所制得的镀金产品作为开关触点，具有良好的抗触点抖动性能和抗电弧烧蚀性能，从而能够提高触点的可靠性和使用寿命。由于触点含有疏水性橡胶层，这种触点适合于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。此外，这种镀金触 点的接触电阻较低，耐大气腐蚀性能好，储存时间和使用寿命长，适合用于作为汽车等高端场合中的橡胶按键的触点。
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、镀金层。
具体实施方式
实施例1：
如图1所示，本产品为3层结构：橡胶层1、金属薄片层2、镀金层3，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。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Elastosil 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。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℃下进行热硫化粘合和热硫化成型，硫化时间为12分钟。形成1.0mm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的小圆粒。把这种小圆粒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左右，然后清洗，沥干。
配置组成如下的化学镀金液：
氰化亚金钾5g/，氰化钾10g/L，柠檬酸钠50g/L，EDTA二钠8g/L，氢氧化钾12g/L，硼氢化钾10g/L，钨酸钠0.5g/L。镀液现配现用。
将这样的500粒小圆片，放入80℃的上述300mL镀液中，不断搅拌，30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金的小圆粒。疏水性橡胶的表面上看不到有沉积的金层。
镀液的配置和化学镀金的实施，需在良好的通风条件下和安全防护下进行，以避免操作人员中毒。
这种含有硅橡胶层的镀金的小圆粒，和硅橡胶进行热硫化粘合和热硫化成型。小圆粒中的硅橡胶面和其它硅橡胶热硫化粘合，有镀金层的一面朝外，以便镀金层可以和其它触点如 印刷电路板(PCB)上的镀金触点接触。这种小圆粒和硅橡胶热硫化成型后，制成了含有触点的橡胶按键(正是这种小圆粒用作了橡胶按键中的触点)。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，较好的耐电弧烧蚀性能和抗触点抖动性能：由没有镀金的锌白铜或镀有镍层的锌白铜制得的小圆粒与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，小圆粒和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，这种有镀金层的触点与PCB镀金触点通过300毫安的直流电，开关约8000次后，这种触点和PCB镀金触点之间的接触电阻，仍在1欧姆以下，而且，镀金后的触点抖动时间，也由没有镀金时的5-25毫秒，降低到2毫秒以下。
实施例2：
所用的金属薄片基材和实施例1一样。将干净的细波纹状的锌白铜片材直接和硅橡胶复合成1.0mm厚的片材，然后，将此片材冲切成直径为3.0mm的小圆粒。将此小圆粒镀上一层2.5μm厚的镍，然后，再将上述镀有镍的小圆粒，按实施例1的方法镀金。所制得的镀金粒，作为橡胶按键的触点，具有较好的耐电弧烧蚀性能和抗触点抖动性能。
实施例3：
镀金前的小圆粒和实施例1一样。所采用的化学镀金液是不含氰的，其化学组成是：氯化金钾2.0g/L，EDTA二钠20g/L，柠檬酸钾5.0g/L，乳酸钠5.0g/L，硫代硫酸钠15g/L，亚硫酸钠15g/L，硫脲20g/L，钨酸钠0.2g/L。氨水适量加入，用氨水调节pH值为8.5-9.5。镀液温度为60℃。化学镀时间为45分钟。如此制得的触点，也具有较好的耐电弧烧蚀性能和抗触点抖动性能。
实施例4：
用400目的不锈钢平纹网(不锈钢材质304)，替代实施例1中的有细波纹状的锌白铜片材，然后采用相同的化学镀液和工艺，也制备得到耐电弧烧蚀性能和抗触点抖动性能较好的镀金的开关触点。

Claims (10)

  1. 一种镀金的开关触点，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0.1mm至10mm厚的疏水性橡胶层，第二层为0.01mm至1.0mm厚的含镁、铝、钛、铬、锰、铁、钴、镍、铜、锌、铌、钼、银、锡、钽或钨的金属薄片层，第三层为0.01-2.0微米厚镀金层；其中，第三层镀金层是第一层和第二层的复合体浸渍在含有可溶性的金化合物的化学镀液中，用化学沉积的方法将金或金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；镀金层中金的含量不小于50％。
  2. 根据权利要求1所述的镀金的开关触点，其特征在于：所述的化学镀液中含有少量可溶性的铅、铊、锡、锑或钨的化合物。
  3. 根据权利要求1所述的镀金的开关触点，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。
  4. 根据权利要求1或2所述的镀金的开关触点，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；作为优选，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。
  5. 根据权利要求1所述的镀金的开关触点，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、钽、钨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。
  6. 根据权利要求1或4所述的镀金的开关触点，其特征在于：所述的金属薄片层的金属薄片由0.01-1.0mm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，或镀有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、纯钴层或钴合金层是由真空镀膜、电镀或化学镀的方法制备的。
  7. 一种镀金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、纯钴层或钴合金层；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；或者将具有自粘性的疏 水性橡胶，通过热硫化粘合和热硫化成型，粘合在涂覆有底涂剂或没有涂覆底涂剂的金属薄片上，形成复层状的合片材；
    (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％的盐酸清洗约1分钟，然后用去离子水清洗干净，沥干；
    (4)镀金层的制备：将上述圆柱体或物体，浸渍在含有可溶性金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镀金层；或者，将上述圆柱体放入含有可溶性金化合物的化学镀液的滚筒中，让滚筒转动，用化学镀的方法在上述圆柱体或物体的金属表面，形成镀金层；
    化学镀液中含有1-15g/L的可溶性金化合物、5-100g/L的络合剂、1-10g/L的稳定剂、5-100g/L的还原剂、0-50g/L的稳定剂、2-50g/L的pH调节剂、0.5mg/L-5g/L的促进剂；
    所述的促进剂是二价的铅化合物、一价的铊化合物、四价的锡化合物、三价的锑化合物或六价的钨化合物；所述的六价的钨化合物钨酸钠、钨酸钾、钨酸铵、六氯化钨；
    (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金的开关触点。
  8. 根据权利要求7所述的镀金的开关触点的制备方法，其特征在于：所述的可溶性金化合物是氰化金钾、氰化亚金钾、氯化金、氯金酸及其盐、氯化金钾和亚硫酸金钠。
  9. 根据权利要求7所述的镀金的开关触点的制备方法，其特征在于：所述的化学镀液是含氰的；化学镀液的组成为：
    Figure PCTCN2015084170-appb-100001
    其中，氰化亚金钾和氰化金钾的总量不小于2g/L，氰化钾、柠檬酸钠、柠檬酸钾、和EDTA二钠的总量不小于5g/L,氢氧化钠和氢氧化钾的总量不小于2g/L，硼氢化钠、硼氢化钾和二甲基硼烷和次磷酸钠的总量不小于5g/L。
  10. 根据权利要求7所述的镀金的开关触点的制备方法，其特征在于：所述的化学镀液是不含氰的；化学镀液的组成为：
    Figure PCTCN2015084170-appb-100002
    其中，亚磷酸金钠、氯化金和氯化金钾的总量不小于2g/L，氰化钾、柠檬酸钠、柠檬酸钾和EDTA二钠的总量不小于5g/L,氢氧化钠和氢氧化钾的总量不小于2g/L，硫代硫酸钠、亚硫酸钠和次磷酸钠的总量不小于5g/L。
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CN106206154A (zh) * 2016-08-18 2016-12-07 南京信息工程大学 一种电控式大功率油开关
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
CN108359966A (zh) * 2017-09-30 2018-08-03 深圳市正天伟科技有限公司 一种半置换半还原型化学镀金液及其应用方法
CN109920661A (zh) * 2019-03-15 2019-06-21 东莞市诒茂电子科技有限公司 双面金属网状导电粒及带有双面金属网状导电粒的按键

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006057131A (ja) * 2004-08-19 2006-03-02 Univ Nagoya 撥水性を有するメッキ層を備えたメッキ製品及びその製造方法
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
CN104112607A (zh) * 2014-07-21 2014-10-22 南通万德科技有限公司 一种镀金的开关触点及其制备方法

Family Cites Families (3)

* 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
EP2032743B1 (en) * 2006-05-24 2010-10-27 ATOTECH Deutschland GmbH Metal plating composition and method for the deposition of copper-zinc-tin suitable for manufacturing thin film solar cell
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

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006057131A (ja) * 2004-08-19 2006-03-02 Univ Nagoya 撥水性を有するメッキ層を備えたメッキ製品及びその製造方法
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
CN104112607A (zh) * 2014-07-21 2014-10-22 南通万德科技有限公司 一种镀金的开关触点及其制备方法

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