Tungsten alloy wire and product and preparation method thereof

Abstract

The invention discloses a tungsten alloy wire which is composed of a tungsten alloy bus and a self-lubricating composite coating, and the self-lubricating composite coating sequentially comprises a pre-coating and a composite coating from inside to outside. The method has the beneficial effects that on one hand, the tungsten alloy bus is subjected to etching treatment through concentrated hydrochloric acid or hydrofluoric acid, and meanwhile, the pre-plating layer is added, so that the binding force between the electroplated layer and the tungsten alloy wire is enhanced; meanwhile, the lubricating composite coating is prepared by adding solid lubricating particles into the electroplating liquid for composite electroplating, so that the die loss in the drawing process is effectively reduced, and the cost is saved; and on the other hand, a nickel aminosulfonate pre-plating process is changed, and impact nickel is used as a pre-plating bottom layer of the diamond wire, so that the binding force of the grinding composite coating and the diamond wire bus is improved, and the problems of wire breakage or silicon wafer scratching and the like caused by falling of the grinding composite coating in the cutting process of the diamond wire can be prevented.

Description

Technical Field

[0001] The invention belongs to the technical field of diamond wires, and in particular relates to a tungsten alloy wire and a product thereof and a preparation method thereof. Background Art

[0002] Due to the advantages of low loss, low TTV, and high cutting efficiency, wire saw cutting is widely used in the cutting of hard and brittle materials such as monocrystalline silicon, polycrystalline silicon, and glass in the photovoltaic, semiconductor information, and LED industries. Wire saw cutting methods are divided into free mortar cutting and fixed abrasive cutting. Free mortar cutting uses bare metal wire to enter the slurry containing silicon carbide abrasives, and cuts by rolling extrusion grinding. This cutting method has problems such as low cutting efficiency and mortar pollution of the environment, and has gradually been replaced by fixed abrasive cutting methods. Fixed abrasive cutting wires are divided into electroplated diamond wire saws and resin diamond wire saws. Resin diamond wires have problems such as the loose bonding between the diamond abrasive and the wire core, and the diamond is easy to fall off during the cutting process. Therefore, the mainstream product on the market is electroplated diamond wire saws.

[0003] Electroplated diamond wire saw is a method of depositing diamond on a metal busbar by electroplating. According to the different metal busbars, it is divided into high-carbon steel diamond wire and tungsten alloy wire diamond wire. In order to reduce non-silicon costs and achieve grid parity, the photovoltaic industry will develop in the direction of thinning the electroplated diamond wire. The theoretical limit of the wire diameter of high-carbon steel diamond wire is about 30μm. Tungsten alloy wire has the advantages of high strength, high temperature resistance, and corrosion resistance. Tungsten alloy wire doped with rare earth elements has good processing performance, and the theoretical limit of the wire diameter is about 22μm, which makes up for the shortcomings of carbon steel wire in terms of wire diameter, tensile strength, and corrosion resistance.

[0004] On the one hand, the traditional method of refining tungsten alloy wire is to cover the surface of tungsten alloy wire with graphite emulsion by spraying, and then heat and dry it, so that a graphite layer with good lubrication performance is formed on the surface of the wire, which can allow the drawing process to continue. However, the differences in the selection of raw materials by different manufacturers lead to large differences in the particle size, suspension, viscosity and other aspects of the graphite emulsion. At the same time, the particle size of graphite powder in the fine wire graphite emulsion of most domestic manufacturers is >3μm. When the particle size of graphite powder is too large, when drawing 30-50μm fine wires, the lubricity of the graphite layer will decrease, increase mold loss and affect the yield of tungsten alloy wire. By using composite electroplating, a metal lubrication layer with fine crystallization, firmness and solid lubrication particles is electroplated on the surface of thick wire tungsten alloy wire, which can solve the problems of poor adhesion of traditional graphite layer and excessive graphite powder particle size, reduce mold loss and improve yield. However, metal tungsten is very active. Under oxygen-containing conditions, a dense black-blue passivation film is easily formed on the surface of tungsten alloy wire, which has high chemical stability. During electroplating, the presence of this passivation film usually results in a weak bond between the plated metal and the tungsten alloy busbar. On the other hand, when preparing diamond wire saws by composite electroplating, the metal tungsten alloy substrate and the electroplated nickel layer are also weakly bonded when electroplating with nickel sulfamate electroplating solution. Therefore, it is necessary to select appropriate pre-treatment methods and electroplating processes to solve the problem of adhesion of the electroplated layer on the surface of the tungsten substrate. Summary of the invention

[0005] In order to overcome the deficiencies of tungsten alloy busbars prepared by the prior art and the deficiencies of diamond wires in terms of yield, mold loss, coating bonding strength, etc., the present invention provides a tungsten alloy wire and its products and a preparation method.

[0006] The first technical solution provided by the present invention is: a tungsten alloy wire, which is composed of a tungsten alloy busbar and a self-lubricating composite coating, wherein the self-lubricating composite coating is a pre-coating and a composite coating from the inside to the outside. The tungsten alloy busbar is composed of metal tungsten and rare earth elements, and the proportion of metal tungsten elements is more than 80wt%, preferably 98.6-99.9wt%; the proportion of rare earth elements is more than 0.1%, preferably 0.1-1.4wt%. The proportion of the metal tungsten element can be 85wt% or 90wt% or 95wt% or 97wt% or 99wt% and a value between any two values; the proportion of rare earth elements is 0.2wt% or 0.5wt% or 0.8wt% or 1.1wt% or 1.4wt% and a value between any two values. Rare earth elements can refine tungsten grains in the tungsten alloy busbar, play a role in dispersion strengthening, and thus improve the tensile strength of the tungsten alloy wire itself. In addition, the rare earth elements in tungsten alloy wire are one or more of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, yttrium and the like.

[0007] The wire diameter of the tungsten alloy wire is 10-200µm, and the tensile strength is above 3000MPa. Furthermore, the wire diameter of the tungsten alloy wire is 10µm, 15µm, 20µm, 25µm, 30µm, 35µm, 40µm, 45µm, 50µm, 55µm, 60µm, 65µm, 70µm, 75µm, 80µm, 85µm, 90µm, 95µm, 100µm, 105µm, 110µm, 115µm, 120µm, 125µm, 130µm, 135µm, 140µm, 145µm, 150µm, 155µm, 160µm, 165µm, 170µm, 175µm, 180µm, 185µm, 190µm, 195µm, 200µm and all ranges and sub-ranges between the above values. The tensile strength of the tungsten alloy wire is 3000 MPa, 4000 MPa, 4500 MPa, 5000 MPa, 5500 MPa, 6000 MPa, 6500 MPa, 7000 MPa and all ranges and sub-ranges between the above values.

[0008] The pre-plating layer is a metal chromium plating layer, and the single-side thickness is 0.1-1µm; the composite plating layer is a metal-based composite plating layer, and the single-side thickness is 0.1-5µm. Furthermore, the single-side thickness of the pre-plating layer is 0.1µm, 0.2µm, 0.3µm, 0.4µm, 0.5µm, 0.6µm, 0.7µm, 0.8µm, 0.9µm, 1µm, and all ranges and sub-ranges between the above values; The composite coating is composed of a metal-based composite coating and a solid lubricant. The metal-based composite coating is one or more of a copper-based composite coating, a tin-based composite coating, a lead-based composite coating, a zinc-based composite coating, a nickel-based composite coating, an iron-based composite coating, a cobalt-based composite coating, etc., and is preferably a copper-based composite coating. Metal copper has good thermal conductivity and electrical conductivity, and also has the characteristics of low hardness and good ductility. During the drawing process of the tungsten alloy wire, it can be deformed simultaneously with the wire.

[0009] The single-side thickness of the composite coating is 0.1µm, 0.5µm, 1µm, 1.5µm, 2µm, 2.5µm, 3µm, 3.5µm, 4µm, 4.5µm, 5µm and all ranges and sub-ranges between the above values. Within this coating thickness range, the tungsten alloy wire can be completely covered by the electroplating layer and has good drawing performance.

[0010] The content of the solid lubricant in the composite coating is 0.1-10wt%. Further, the content of the solid lubricant in the composite coating is 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, 8.5wt%, 9wt%, 9.5wt%, 10wt% and all ranges and sub-ranges between the above values.

[0011] The particle size of the solid lubricant is 2-10 μm. For example, the particle size of the solid lubricant can be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm and all ranges and sub-ranges between the above values. Within this particle size range, the solid particles can be uniformly dispersed in the plating solution.

[0012] The solid lubricant is composed of 0-100 wt% of metal compounds, 0-100 wt% of inorganic substances and 0-100 wt% of organic substances, wherein the metal compounds include one or more of metal oxides, metal halides, metal sulfides and metal selenides; the inorganic substances are one or more of graphite, graphite fluoride and hexagonal boron nitride; and the organic substances are one or more of polytetrafluoroethylene, polyimide, nylon, polyethylene and melamine urate.

[0013] Furthermore, the metal oxide is one or more of metal oxides selected from lead oxide, copper oxide, zinc oxide, tin oxide, molybdenum oxide, etc.; the metal sulfide is one or more of metal sulfides selected from molybdenum disulfide, tungsten disulfide, iron sulfide, chromium sulfide, etc.; the metal halide is one or more of metal halides selected from calcium fluoride, barium fluoride, lanthanum fluoride, etc.; the metal selenide is niobium diselenide; the inorganic solid lubricant is one or more of inorganic substances selected from graphite, graphite fluoride, hexagonal boron nitride, etc.; the organic solid lubricant is one or more of organic solid lubricants selected from polytetrafluoroethylene, polyimide, nylon, polyethylene, melamine urate, etc. Preferably, the solid lubricant is composed of 30-40 wt% of metal compound, 30-40 wt% of inorganic substance and 30-40 wt% of organic substance.

[0014] In some preferred embodiments, the solid lubricant is molybdenum disulfide. Molybdenum disulfide has a hexagonal layered structure similar to graphite, and each unit layer is composed of three superimposed plane layers of S-MO-S. The sulfur atoms are connected to the corresponding molybdenum atoms by strong covalent bonds, and surround the molybdenum in the center like a triangular prism. The distance between unit layers is 0.625nm, and the van der Waals force between adjacent layers is weak, which greatly reduces the shear force during the dislocation sliding between the layers. Therefore, molybdenum disulfide has very excellent solid lubrication properties. In addition, molybdenum disulfide has good corrosion resistance and electrical conductivity, and the operating temperature in the atmospheric environment can reach 350°C, so it can exist stably in the electroplating solution, and at the same time, it is composited with the metal ions in the plating solution and deposited on the tungsten alloy wire under the action of the electric field force.

[0015] The present invention also provides a method for preparing the aforementioned tungsten alloy wire, comprising the following steps: Step 1: Pre-treat the tungsten alloy busbar; Step 2: electroplating, placing the tungsten alloy busbar obtained in step 1 in an electroplating tank to electroplate a pre-plating layer, and then electroplating a composite coating layer in the electroplating tank. After the electroplating is completed, the tungsten alloy wire is washed and soap-soaked, and then the wire is collected on the I-shaped wheel; Step 3: Drawing, install the tungsten alloy wire obtained in step 2 at the wire pay-off end of the water tank drawing machine, and the tungsten alloy wire reaches the required wire diameter after multiple drawing passes. Preferably, the outlet die in the drawing machine uses a natural diamond die, which can improve the surface quality of the tungsten wire and reduce the ovality of the tungsten wire.

[0016] The detailed steps of the pre-treatment in step 1 are: Step A, place the tungsten alloy busbar in an ultrasonic electrolytic alkaline washing tank for cleaning, the alkaline solution composition is one or more of sodium hydroxide, sodium carbonate, and trisodium phosphate, the alkaline solution concentration is 50-150g / L, the temperature is 50-80°C, the degreasing time is 1-5s, and the ultrasonic frequency is 10-100Hz. The tungsten alloy busbar has good corrosion resistance. It is insoluble in strong acids such as hydrochloric acid, sulfuric acid, and nitric acid at room temperature, and is only soluble in a mixed acid of hydrofluoric acid and concentrated nitric acid. After the tungsten alloy busbar is oxidized, the tungsten oxide formed on the surface is easily soluble in alkaline solution. Usually, after the tungsten alloy busbar is drawn with graphite emulsion, graphite and organic solvents may still remain on the surface. Therefore, it is necessary to remove impurities such as oxide scale, graphite emulsion, and organic solvents remaining on the surface of the tungsten alloy busbar by anodic oxidation of the tungsten wire and dissolving it in alkaline solution.

[0017] Step B, two-stage water washing, using countercurrent water washing method, after degreasing, the tungsten alloy busbar first enters the hot water washing tank, the water temperature is 50-70℃, the time is 1-5S, and then passes through the cold water washing tank; Step C, use concentrated hydrochloric acid or hydrofluoric acid to activate the surface of the tungsten alloy busbar, the acid temperature is 10-30°C, the time is 1-5S, and then activated with water washing. The activation mechanism in the pretreatment and electroplating process of the present invention is: hydrofluoric acid is highly corrosive, and the chemical strong corrosion of hydrofluoric acid removes the passivation film on the surface of the tungsten wire, and the surface of the tungsten wire is coarsened. There are gaps between the grains of the tungsten wire, and some are in the shape of barbs. When electroplating on such a surface, the chromium layer will firmly lock itself on the surface of the tungsten wire, thereby enhancing the bonding force between the chromium plating layer and the tungsten alloy wire. At the same time, metallic chromium and tungsten have the same body-centered cubic structure and similar thermal expansion coefficients, so chromium is selected as the pre-plating layer. When preparing a diamond wire saw, impact nickel is used for pre-plating. During the pre-plating process, hydrogen with strong reducing properties is precipitated on the cathode wire body, which plays a role in further activating the metal surface.

[0018] The process of electroplating the pre-plating layer in step 2 is: the current density is 4-20A / dm 2 , the electroplating time is 1-30S; the anode is a lead-tin alloy or a platinum-iridium anode; the electroplating solution composition is chromic anhydride: 100-400g / L, sulfuric acid 1-5g / L, La 3+ : 0.1-2.5g / L.

[0019] The process of electroplating the composite coating in step 2 is as follows: the electroplating solution composition is 250g / L of one or more of metal oxides, metal halides, metal sulfides, metal selenides, 100g / L of sulfuric acid, and 0.1-100g / L of solid lubricant; the current density is 8-10A / dm 2 The solid lubricant has a concentration of 0.1-100 g / L in the electroplating solution. For example, the solid lubricant concentration is 10 g / L, 20 g / L, 30 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L and all ranges and sub-ranges between the above values. Within this concentration range, the lubricating coating has a high particle content and good lubricity.

[0020] The present invention also provides a diamond wire saw made of the aforementioned tungsten alloy wire and a preparation method thereof, wherein the aforementioned tungsten alloy wire is subjected to alkali washing and acid washing pre-treatment according to the prior art, and after being primed with impact nickel, the diamond wire saw is prepared by composite electroplating. Preferably, the acid washing uses one or more of aminosulfonic acid, hydrochloric acid or sulfuric acid. The components of the impact nickel plating solution are nickel chloride: 200-300g / L, hydrochloric acid: 100-200ml / L, and the current density is 1-15A / dm 2 , the plating time is 5-15s, and the plating solution temperature is 15-35℃.

[0021] The beneficial effects of the present invention are as follows: on the one hand, the tungsten alloy busbar is etched by concentrated hydrochloric acid or hydrofluoric acid, and a pre-plating layer is added at the same time, thereby enhancing the bonding strength between the electroplating layer and the tungsten alloy wire. At the same time, a lubricating composite plating layer is prepared by adding solid lubricating particles to the plating solution for composite electroplating, thereby effectively reducing the mold loss during the drawing process and saving costs; on the other hand, the pre-plating process of nickel sulfamate is changed, and impact nickel is used as the pre-plating bottom layer of the diamond wire, thereby enhancing the bonding strength between the grinding composite plating layer and the diamond wire busbar, thereby preventing problems such as wire breakage or silicon wafer scratches caused by the shedding of the grinding composite plating layer during the cutting process of the diamond wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the cross section of the tungsten alloy wire of the present invention; Figure 2 This is a process flow chart of manufacturing tungsten alloy wire of the present invention; Figure 3 The present invention is a manufacturing process flow chart of the diamond wire saw; Figure 4 This is a scanning electron microscope image of the product prepared in Example 1 of the present invention; Figure 5 This is a scanning electron microscope image of the product prepared according to Comparative Example 1 of the present invention; Figure 6 This is a scanning electron microscope image of the product prepared in Example 2 of the present invention.

[0023] Among them: 1-tungsten alloy busbar, 2-pre-plating layer, 3-composite coating layer. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] like Figure 2 and Figure 3 As shown, in some embodiments, a method for preparing a tungsten alloy wire and a diamond wire comprises the following steps: Step 1: Pre-treatment of tungsten alloy busbar.

[0026] The pre-treatment step in step one is to put the tungsten alloy busbar from the wire-releasing end into the ultrasonic electrolysis alkaline washing tank, and then enter the electroplating tank after three steps of water washing, acid washing and water washing. The tungsten alloy busbar has good corrosion resistance. It is insoluble in strong acids such as hydrochloric acid, sulfuric acid, and nitric acid at room temperature. It is only soluble in a mixed acid of hydrofluoric acid and concentrated nitric acid. After the tungsten alloy busbar is oxidized, the tungsten oxide formed on the surface is easily soluble in alkaline solution. Usually, after the tungsten alloy busbar is drawn with graphite emulsion, graphite and organic solvents may still remain on the surface. Therefore, it is necessary to remove impurities such as oxide scale, graphite emulsion and organic solvents remaining on the surface of the tungsten alloy busbar by anodic oxidation of the tungsten wire and dissolving it in alkaline solution. The water washing is a two-stage water washing method, which adopts a countercurrent water washing method. After the tungsten alloy busbar is electrolyzed, it first enters the hot water washing tank, then enters the acid washing activation tank after passing through the cold water washing tank, and is washed again with deionized water before entering the electroplating tank.

[0027] In some embodiments, the alkali solution composition is one or more of sodium hydroxide, sodium carbonate, and trisodium phosphate, the alkali solution concentration is 50-150g / L, the temperature is 50-80°C, the oil removal time is 1-5s, and the ultrasonic frequency is 10-100Hz; the water temperature of the washing tank after electrolytic cleaning is 50-70°C, and the time is 1-5S.

[0028] In some embodiments, the acid solution uses concentrated hydrochloric acid or hydrofluoric acid to activate the surface of the tungsten alloy wire, and the acid solution temperature is 10-30° C. and the time is 1-5S.

[0029] Step 2: Electroplating self-lubricating composite coating. After activated water washing, the tungsten alloy busbar enters the electroplating tank for pre-plating of the bottom metal coating, and then enters the electroplating tank for electroplating of the lubricating composite coating. After the electroplating is completed, the wire is washed, dried, and soap-soaked, and the servo motor is used to reel the wire onto the I-shaped wheel at a certain pitch.

[0030] In some embodiments, the impact chromium plating solution comprises chromic anhydride: 100-400 g / L, sulfuric acid 1-5 g / L, La 3+ :0.1-2.5g / L Current density is 4-20A / dm 2 The electroplating time is 1-30S, and the anode is a lead-tin alloy or a platinum-iridium anode.

[0031] In some preferred embodiments, the lubricating composite coating is a copper-based composite coating, and the solid lubricant is molybdenum disulfide. The plating solution contains 200-300 g / L copper sulfate and 100-200 g / L sulfuric acid, the temperature is 10-30°C, and the current density is 5-20 A / dm 2 The wire is dried in a heating furnace at a temperature of 200-300°C for 1-5 seconds. After the wire is soaked in soap, a lubricating film can be formed on the surface to prevent oxidation of the steel wire surface, which is beneficial for wire arrangement at the take-up end and subsequent drawing.

[0032] Step 3: Drawing, install the electroplated tungsten alloy wire on the wire pay-off end of the water tank drawing machine, and the alloy wire diameter reaches the required wire diameter after multiple die drawing; In some embodiments, the outlet mold is a natural diamond mold, which can improve the surface quality of the tungsten wire and reduce the ovality of the tungsten wire.

[0033] Furthermore, step 4 can be performed: the drawn tungsten alloy wire is subjected to alkali washing, water washing, and pickling pretreatment, and after impact nickel priming, a diamond wire saw is prepared by composite electroplating. Acid washing uses one or more of aminosulfonic acid, hydrochloric acid or sulfuric acid. The components of the impact nickel plating solution are nickel chloride: 200-300g / L, hydrochloric acid: 100-200ml / L, and the current density is 1-15A / dm 2 The electroplating time is 5-15s, the electroplating solution temperature is 15-35°C, the single-side coating thickness is 0.1-1μm, and then a diamond wire saw is obtained.

[0034] Example 1

[0035] This embodiment provides a tungsten alloy wire and a preparation method thereof. The tungsten alloy wire is prepared according to the following steps: Step 1: The tungsten alloy busbar enters the ultrasonic electrolytic alkali washing tank from the pay-off end. The alkali solution is composed of sodium hydroxide, the concentration is 70g / L, the alkali solution temperature is 70℃, the alkali washing time is 5s, and the ultrasonic frequency is 25HZ. The deoiled tungsten alloy wire enters the hot water and cold water secondary washing tank, and the alkali on the surface of the tungsten wire is completely cleaned by countercurrent. The hot water washing temperature is 60℃ and the cold water washing temperature is 25℃. The washed tungsten alloy wire enters the pickling activation tank and is etched and activated with hydrofluoric acid. The hydrofluoric acid concentration is 20%, the temperature is 25℃, and the activation time is 3s.

[0036] Step 2: Electroplating is performed after pretreatment. First, metal chromium is pre-plated on the surface of the tungsten alloy busbar as the bottom bonding layer. The impact chromium anode is a lead-tin alloy, and the electroplating solution is composed of chromic anhydride: 250g / L, sulfuric acid: 2g / L, lanthanum nitrate: 5g / L, and the current density is 15A / dm 2 , the electroplating time is 9s, and the single-side coating thickness is 0.5μm. After the pre-plating is completed, the copper layer is electroplated on the metal chromium. The electroplating solution composition is copper sulfate: 250g / L, sulfuric acid 100g / L, and the current density is 10A / dm 2 The thickness of the single-side coating is 2μm. After washing, drying and soap dipping, the servo motor takes up the wire on the I-shaped wheel at a certain pitch.

[0037] Step 3: Drawing. Install the electroplated tungsten alloy wire on the wire-paying end of the water tank drawing machine. After multiple passes of die drawing, the alloy wire reaches the required wire diameter and obtains the final product.

[0038] Example 2

[0039] This embodiment provides a tungsten alloy wire and a preparation method thereof. The tungsten alloy wire is prepared according to the following steps: Step 1: The tungsten alloy busbar enters the ultrasonic electrolytic alkali washing tank from the pay-off end. The alkali solution is composed of sodium hydroxide, the concentration is 70g / L, the alkali solution temperature is 70℃, the alkali washing time is 5s, and the ultrasonic frequency is 25HZ. The deoiled tungsten alloy wire enters the hot water and cold water secondary washing tank, and the alkali solution on the surface of the tungsten alloy busbar is completely cleaned by countercurrent. The hot water washing temperature is 60℃ and the cold water washing temperature is 25℃. The washed tungsten alloy busbar enters the pickling activation tank, and is etched and activated with hydrofluoric acid. The hydrofluoric acid concentration is 20%, the temperature is 25℃, and the activation time is 3s.

[0040] Step 2: After the pretreatment is completed, self-lubricating composite coating is electroplated. First, metal chromium is pre-plated on the surface of the tungsten alloy busbar as the bottom bonding layer. The impact chromium anode is a lead-tin alloy, and the electroplating solution is composed of chromic anhydride: 250g / L, sulfuric acid: 2g / L, lanthanum nitrate: 5g / L, and the current density is 15A / dm 2 , the electroplating time is 9s, and the single-side coating thickness is 0.5μm. After the pre-plating is completed, a copper-based lubricating composite coating is electroplated on the metal chromium. The electroplating solution composition is copper sulfate: 250g / L, sulfuric acid 100g / L, and the current density is 10A / dm 2 Solid lubricating particles are molybdenum disulfide, with a particle concentration of 50g / L, a particle size of 2μm, and a single-side coating thickness of 2μm. After washing, drying, and soap dipping, the servo motor takes up the wire on the I-shaped wheel at a certain pitch.

[0041] Step 3: Drawing. Install the electroplated tungsten alloy wire on the wire-paying end of the water tank drawing machine. After multiple passes of die drawing, the alloy wire reaches the required wire diameter and the final product is obtained. The product structure diagram is shown in the figure. Figure 1 shown.

[0042] Example 3

[0043] This embodiment provides a tungsten alloy wire and a preparation method thereof. The tungsten alloy wire is prepared according to the following steps: Step 1: The tungsten alloy busbar enters the ultrasonic electrolytic alkali washing tank from the pay-off end. The alkali solution is composed of sodium hydroxide, the concentration is 70g / L, the alkali solution temperature is 70℃, the alkali washing time is 5s, and the ultrasonic frequency is 25HZ. The deoiled tungsten alloy wire enters the hot water and cold water secondary washing tank, and the alkali solution on the surface of the tungsten alloy busbar is completely cleaned by countercurrent. The hot water washing temperature is 60℃ and the cold water washing temperature is 25℃. The washed tungsten alloy busbar enters the pickling activation tank, and is etched and activated with hydrofluoric acid. The hydrofluoric acid concentration is 20%, the temperature is 25℃, and the activation time is 3s.

[0044] Step 2: After the pretreatment is completed, self-lubricating composite coating is electroplated. First, metal chromium is pre-plated on the surface of the tungsten alloy busbar as the bottom bonding layer. The impact chromium anode is a lead-tin alloy, and the electroplating solution is composed of chromic anhydride: 250g / L, sulfuric acid: 2g / L, lanthanum nitrate: 5g / L, and the current density is 15A / dm 2 , the electroplating time is 9s, and the single-side coating thickness is 0.5μm. After the pre-plating is completed, a copper-based lubricating composite coating is electroplated on the metal chromium. The electroplating solution composition is zinc sulfate: 250g / L, sulfuric acid 100g / L, and the current density is 10A / dm 2 The solid lubricating particles are niobium diselenide, with a particle concentration of 50g / L, a particle size of 2μm, and a single-side coating thickness of 2μm. After washing, drying, and soap dipping, the servo motor takes up the wire on the I-shaped wheel at a certain pitch.

[0045] Step 3: Drawing. Install the electroplated tungsten alloy wire on the wire-paying end of the water tank drawing machine. After multiple passes of die drawing, the alloy wire reaches the required wire diameter and obtains the final product.

[0046] Example 4

[0047] This embodiment provides a tungsten alloy wire and a preparation method thereof. The tungsten alloy wire is prepared according to the following steps: Step 1: The tungsten alloy busbar enters the ultrasonic electrolytic alkali washing tank from the pay-off end. The alkali solution is composed of sodium hydroxide, the concentration is 70g / L, the alkali solution temperature is 70℃, the alkali washing time is 5s, and the ultrasonic frequency is 25HZ. The deoiled tungsten alloy wire enters the hot water and cold water secondary washing tank, and the alkali solution on the surface of the tungsten alloy busbar is completely cleaned by countercurrent. The hot water washing temperature is 60℃ and the cold water washing temperature is 25℃. The washed tungsten alloy busbar enters the pickling activation tank, and is etched and activated with hydrofluoric acid. The hydrofluoric acid concentration is 20%, the temperature is 25℃, and the activation time is 3s.

[0048] Step 2: After the pretreatment is completed, self-lubricating composite coating is electroplated. First, metal chromium is pre-plated on the surface of the tungsten alloy busbar as the bottom bonding layer. The impact chromium anode is a lead-tin alloy, and the electroplating solution is composed of chromic anhydride: 250g / L, sulfuric acid: 2g / L, lanthanum nitrate: 5g / L, and the current density is 15A / dm 2 , the electroplating time is 9s, and the single-side coating thickness is 0.5μm. After the pre-plating is completed, a copper-based lubricating composite coating is electroplated on the metal chromium. The electroplating solution composition is tin sulfate: 250g / L, sulfuric acid 100g / L, and the current density is 10A / dm 2 Solid lubricating particles are molybdenum disulfide, with a particle concentration of 50g / L, a particle size of 2μm, and a single-side coating thickness of 2μm. After washing, drying, and soap dipping, the servo motor takes up the wire on the I-shaped wheel at a certain pitch.

[0049] Step 3: Drawing. Install the electroplated tungsten alloy wire on the wire-paying end of the water tank drawing machine. After multiple passes of die drawing, the alloy wire reaches the required wire diameter and obtains the final product.

[0050] Example 5

[0051] This embodiment provides a tungsten alloy wire and a preparation method thereof. The tungsten alloy wire is prepared according to the following steps: Step 1: The tungsten alloy busbar enters the ultrasonic electrolytic alkali washing tank from the pay-off end. The alkali solution is composed of sodium hydroxide, the concentration is 70g / L, the alkali solution temperature is 70℃, the alkali washing time is 5s, and the ultrasonic frequency is 25HZ. The deoiled tungsten alloy wire enters the hot water and cold water secondary washing tank, and the alkali solution on the surface of the tungsten alloy busbar is completely cleaned by countercurrent. The hot water washing temperature is 60℃ and the cold water washing temperature is 25℃. The washed tungsten alloy busbar enters the pickling activation tank, and is etched and activated with hydrofluoric acid. The hydrofluoric acid concentration is 20%, the temperature is 25℃, and the activation time is 3s.

[0052] Step 2: After the pretreatment is completed, self-lubricating composite coating is electroplated. First, metal chromium is pre-plated on the surface of the tungsten alloy busbar as the bottom bonding layer. The impact chromium anode is a lead-tin alloy, and the electroplating solution is composed of chromic anhydride: 250g / L, sulfuric acid: 2g / L, lanthanum nitrate: 5g / L, and the current density is 15A / dm 2 , the electroplating time is 9s, and the single-side coating thickness is 0.5μm. After the pre-plating is completed, the copper-based lubricating composite coating is electroplated on the metal chromium. The electroplating solution composition is molybdenum sulfate: 250g / L, sulfuric acid 100g / L, and the current density is 10A / dm 2 The solid lubricating particles are molybdenum disulfide (40wt%) + graphite (30wt%) + polyethylene (30wt%), with a particle concentration of 50g / L, a particle size of 2μm, and a single-side coating thickness of 2μm. After washing, drying, and soap dipping, the servo motor takes up the wire on the I-shaped wheel at a certain pitch.

[0053] Step 3: Drawing. Install the electroplated tungsten alloy wire on the wire-paying end of the water tank drawing machine. After multiple passes of die drawing, the alloy wire reaches the required wire diameter and obtains the final product.

[0054] Example 6

[0055] This embodiment provides a tungsten alloy wire and a preparation method thereof. The tungsten alloy wire is prepared according to the following steps: Step 1: The tungsten alloy busbar enters the ultrasonic electrolytic alkali washing tank from the pay-off end. The alkali solution is composed of sodium hydroxide, the concentration is 70g / L, the alkali solution temperature is 70℃, the alkali washing time is 5s, and the ultrasonic frequency is 25HZ. The deoiled tungsten alloy wire enters the hot water and cold water secondary washing tank, and the alkali solution on the surface of the tungsten alloy busbar is completely cleaned by countercurrent. The hot water washing temperature is 60℃ and the cold water washing temperature is 25℃. The washed tungsten alloy busbar enters the pickling activation tank, and is etched and activated with hydrofluoric acid. The hydrofluoric acid concentration is 20%, the temperature is 25℃, and the activation time is 3s.

[0056] Step 2: After the pretreatment is completed, self-lubricating composite coating is electroplated. First, metal chromium is pre-plated on the surface of the tungsten alloy busbar as the bottom bonding layer. The impact chromium anode is a lead-tin alloy, and the electroplating solution is composed of chromic anhydride: 250g / L, sulfuric acid: 2g / L, lanthanum nitrate: 5g / L, and the current density is 15A / dm 2 , the electroplating time is 9s, and the single-side coating thickness is 0.5μm. After the pre-plating is completed, a copper-based lubricating composite coating is electroplated on the metal chromium. The electroplating solution composition is copper sulfate: 250g / L, sulfuric acid 100g / L, and the current density is 10A / dm 2 The solid lubricating particles are graphite (50wt%) + polyethylene (50wt%), with a particle concentration of 50g / L, a particle size of 2μm, and a single-side coating thickness of 2μm. After washing, drying, and soap dipping, the servo motor is used to collect the wire onto the I-shaped wheel at a certain pitch.

[0057] Step 3: Drawing. Install the electroplated tungsten alloy wire on the wire-paying end of the water tank drawing machine. After multiple passes of die drawing, the alloy wire reaches the required wire diameter and obtains the final product.

[0058] Comparative Example 1 This comparative example provides a tungsten alloy wire and a preparation method thereof. The tungsten alloy wire is prepared according to the following steps: Step 1: The tungsten alloy busbar enters the ultrasonic electrolytic alkali washing tank from the pay-off end. The alkali solution is composed of sodium hydroxide, the concentration is 70g / L, the alkali solution temperature is 70℃, the alkali washing time is 5s, and the ultrasonic frequency is 25HZ. The deoiled tungsten alloy wire enters the hot water and cold water secondary washing tank, and the alkali solution on the surface of the tungsten alloy busbar is completely cleaned by countercurrent. The hot water washing temperature is 60℃ and the cold water washing temperature is 25℃. The washed tungsten alloy busbar enters the pickling activation tank, and is etched and activated with hydrofluoric acid. The hydrofluoric acid concentration is 20%, the temperature is 25℃, and the activation time is 3s.

[0059] Step 2: After the pretreatment is completed, electroplating is performed. The copper layer is electroplated on the tungsten alloy busbar. The electroplating solution composition is copper sulfate: 250g / L, sulfuric acid 100g / L, and the current density is 10A / dm 2The thickness of the single-side coating is 2μm. After washing, drying and soap dipping, the servo motor takes up the wire on the I-shaped wheel at a certain pitch.

[0060] Step 3: Drawing. Install the electroplated tungsten alloy wire on the wire-paying end of the water tank drawing machine. After multiple passes of die drawing, the alloy wire reaches the required wire diameter and obtains the final product.

[0061] Comparative Example 2 This comparative example provides a tungsten alloy wire and a preparation method thereof. The tungsten alloy wire is prepared according to the following steps: Step 1: The tungsten alloy busbar enters the ultrasonic electrolytic alkali washing tank from the pay-off end. The alkali solution is composed of sodium hydroxide, the concentration is 70g / L, the alkali solution temperature is 70℃, the alkali washing time is 5s, and the ultrasonic frequency is 25HZ. After degreasing, the tungsten alloy busbar enters the hot water and cold water secondary washing tank, and the alkali solution on the surface of the tungsten alloy busbar is completely cleaned by countercurrent. The hot water washing temperature is 60℃ and the cold water washing temperature is 25℃. After washing, the tungsten alloy busbar enters the pickling activation tank, and is etched and activated with hydrofluoric acid. The hydrofluoric acid concentration is 20%, the temperature is 25℃, and the activation time is 3s.

[0062] Step 2: Electroplating is performed after pretreatment. First, metal chromium is pre-plated on the surface of the tungsten alloy busbar as the bottom bonding layer. The impact chromium anode is a lead-tin alloy, and the electroplating solution is composed of chromic anhydride: 250g / L, sulfuric acid: 2g / L, lanthanum nitrate: 5g / L, and the current density is 15A / dm 2 , the electroplating time is 9s, and the single-side coating thickness is 0.5μm. After the pre-plating is completed, the copper layer is electroplated on the metal chromium. The electroplating solution composition is copper sulfate: 250g / L, sulfuric acid 100g / L, and the current density is 10A / dm 2 , the single-side coating thickness is 2μm.

[0063] Step 3: Drawing. Install the electroplated tungsten alloy wire on the wire-paying end of the water tank drawing machine. The alloy wire reaches the required wire diameter after multiple die drawing.

[0064] Comparative Example 3 This comparative example provides a tungsten alloy wire and a preparation method thereof. The tungsten alloy wire is prepared according to the following steps: Step 1: The tungsten alloy busbar enters the ultrasonic electrolytic alkali washing tank from the pay-off end. The alkali solution is composed of sodium hydroxide, the concentration is 70g / L, the alkali solution temperature is 70℃, the alkali washing time is 5s, and the ultrasonic frequency is 25HZ. After degreasing, the tungsten alloy busbar enters the hot water and cold water secondary washing tank, and the alkali solution on the surface of the tungsten alloy busbar is completely cleaned by countercurrent. The hot water washing temperature is 60℃ and the cold water washing temperature is 25℃. After washing, the tungsten alloy busbar enters the pickling activation tank, and is etched and activated with hydrofluoric acid. The hydrofluoric acid concentration is 20%, the temperature is 25℃, and the activation time is 3s.

[0065] Step 2: Electroplating is performed after pretreatment. First, metal chromium is pre-plated on the surface of the tungsten alloy busbar as the bottom bonding layer. The impact chromium anode is a lead-tin alloy, and the electroplating solution is composed of chromic anhydride: 250g / L, sulfuric acid: 2g / L, lanthanum nitrate: 5g / L, and the current density is 15A / dm 2 , the plating time is 9s, and the thickness of the single-side coating is 0.5μm. After the pre-plating is completed, the copper layer is electroplated on the metal chromium. The plating solution composition is copper pyrophosphate: 300g / L, potassium pyrophosphate 100g / L, and the current density is 8A / dm 2 , the single-side coating thickness is 2μm.

[0066] Step 3: Drawing. Install the electroplated tungsten alloy wire on the wire-paying end of the water tank drawing machine. The tungsten alloy wire reaches the required wire diameter after multiple die drawing.

[0067] Comparative Example 4 This comparative example provides a tungsten alloy wire and a preparation method thereof. The tungsten alloy wire is prepared according to the following steps: Step 1: Pre-plating metal chromium on the surface of the tungsten alloy busbar as the bottom bonding layer. The impact chromium anode is a lead-tin alloy, the plating solution composition is chromic anhydride: 250g / L, sulfuric acid: 2g / L, lanthanum nitrate: 5g / L, and the current density is 15A / dm 2 , the electroplating time is 9s, and the single-side coating thickness is 0.5μm. After the pre-plating is completed, a copper-based lubricating composite coating is electroplated on the metal chromium. The electroplating solution composition is copper sulfate: 250g / L, sulfuric acid 100g / L, and the current density is 10A / dm 2 Solid lubricating particles are molybdenum disulfide, with a particle concentration of 50g / L, a particle size of 2μm, and a single-side coating thickness of 2μm. After washing, drying, and soap dipping, the servo motor takes up the wire on the I-shaped wheel at a certain pitch.

[0068] Step 3: Drawing. Install the electroplated tungsten alloy wire on the wire-paying end of the water tank drawing machine. After multiple passes of die drawing, the alloy wire reaches the required wire diameter and obtains the final product.

[0069] Depend on Figure 4 , Figure 5 Corresponding to Example 1 and Comparative Example 1 respectively, Figure 4 and 5 It can be seen that after the pre-plating of the metal chromium layer, the coating has a good bonding strength with the tungsten alloy wire substrate, and there is no coating peeling after knotting.

[0070] The tungsten alloy wires prepared in Examples 2-6 and Comparative Examples 1-4 were tested for breaking tension, number of torsion turns, circle diameter, and pulling. The experimental results are shown in Tables 1 and 2: Table 1 Busbar specification (μm) Breaking force (N) Twist number Ring diameter (cm) Tensile strength (MPa) Example 2 31 4.97 285 12 6591 Example 3 31 4.94 283 9 6551 Example 4 31 4.96 285 11 6578 Example 5 31 4.97 287 10 6591 Example 6 31 4.96 286 9 6578 Comparative Example 1 31 4.71 283 7 6246 Comparative Example 2 31 4.95 278 7 6564 Comparative Example 3 31 4.93 296 8 6538 Comparative Example 4 31 4.73 281 8 6273 It can be seen from Table 1 that after the self-lubricating composite coating is added in Example 2, the physical properties of the tungsten alloy wire, such as breaking tensile force, number of torsion circles and circle diameter, are slightly higher than those of the uncoated tungsten alloy wire; while the breaking tensile force of the tungsten alloy wire without pretreatment is lower than that of the tungsten alloy wire after pretreatment.

[0071] Table 2 Mold specification (μm) 56 52 49 45 42 39 37 35 33 31 Example 2 Product mold usage mileage 975 983 967 988 935 946 831 835 867 889 Example 3 Product mold usage mileage 986 964 982 979 954 943 865 836 876 891 Example 4 Product mold usage mileage 975 973 962 984 964 968 873 875 868 817 Example 5 Product mold usage mileage 983 987 967 951 964 986 835 834 846 862 Example 6 Product mold usage mileage 968 946 978 923 956 986 846 815 835 864 Comparative Example 1 Product Mold Usage Kilometers 523 534 564 562 543 535 365 354 336 346 Comparative Example 2 Product Mold Usage Kilometers 986 956 946 953 943 985 346 378 397 339 Comparative Example 3 Product Mold Usage Kilometers 946 953 958 912 934 948 348 365 346 359 Comparative Example 4 Product Mold Usage Kilometers 495 452 462 475 435 461 333 327 342 312 According to the test results in Table 2, the mileage of tungsten alloy wire drawn by direct electroplated copper layer and other single coatings is 400km, and the aperture of the last four dies will gradually become larger and cannot be used any more. However, for electroplated self-lubricating composite coatings, the mileage of tungsten alloy wire drawn by the last four dies is more than 800km, which can effectively reduce the die loss.

[0072] The difference between Example 7-12 and Example 2 is that tungsten alloy busbars with different busbar diameters are prepared and made into diamond wire saws. The client performance of the diamond wire saw is shown in Table 3.

[0073] Table 3 Busbar specification (μm) Twist number Ring diameter (cm) Tensile strength (MPa) Client performance (line mark rate %) Example 7 30 292 8 6584 0.86 Example 8 40 382 10 6323 1.21 Example 9 50 375 7 5986 0.97 Example 10 60 438 8 5648 1.03 Embodiment 11 70 372 8 5423 1.12 Example 12 80 468 9 5272 1.06

[0074] Finally, it should be noted that the above is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied for herein.

Claims

1. A tungsten alloy wire, characterized in that: The invention is composed of a tungsten alloy busbar and a self-lubricating composite coating, wherein the self-lubricating composite coating is composed of a pre-coating layer and a composite coating from the inside to the outside.

2. The tungsten alloy wire according to claim 1, characterized in that: The wire diameter of the tungsten alloy wire is 10-200µm, and the tensile strength is above 3000MPa.

3. The tungsten alloy wire according to claim 1, characterized in that: The pre-plating layer is a metal chromium plating layer with a single-side thickness of 0.1-1µm; the composite plating layer is a metal-based composite plating layer with a single-side thickness of 0.1-5µm.

4. The tungsten alloy wire according to claim 3, characterized in that: The metal-based composite coating contains a solid lubricant, and the content of the solid lubricant in the metal-based composite coating is 0.1-10 wt %.

5. The tungsten alloy wire according to claim 4, characterized in that: The solid lubricant is composed of 0-100 wt% of metal compounds, 0-100 wt% of inorganic substances and 0-100 wt% of organic substances, wherein the metal compounds include one or more of metal oxides, metal halides, metal sulfides and metal selenides; the inorganic substances are one or more of graphite, graphite fluoride and hexagonal boron nitride; and the organic substances are one or more of polytetrafluoroethylene, polyimide, nylon, polyethylene and melamine urate.

6. A tungsten alloy wire product, characterized in that: The tungsten alloy wire is obtained by processing the tungsten alloy wire according to any one of claims 1 to 5.

7. A method for preparing a tungsten alloy wire, characterized in that: The following steps are involved: Step 1: Pre-treat the tungsten alloy busbar; Step 2: electroplating, placing the tungsten alloy busbar obtained in step 1 in an electroplating tank to electroplate a pre-plating layer, and then electroplating a composite coating layer in the electroplating tank. After the electroplating is completed, the tungsten alloy wire is washed and soap-soaked, and then the wire is collected on the I-shaped wheel; Step 3: Drawing. Install the tungsten alloy wire obtained in step 2 at the wire-paying end of the water tank drawing machine. The tungsten alloy wire can reach the required wire diameter after multiple drawing passes.

8. The method for preparing tungsten alloy wire according to claim 7, characterized in that: The detailed steps of the pre-treatment in step 1 are: Step A, placing the tungsten alloy busbar in an ultrasonic electrolytic alkali cleaning tank for cleaning, wherein the alkali solution comprises one or more of sodium hydroxide, sodium carbonate, and trisodium phosphate, wherein the alkali solution concentration is 50-150 g / L, the temperature is 50-80° C., the degreasing time is 1-5 s, and the ultrasonic frequency is 10-100 Hz; Step B, two-stage water washing, using countercurrent water washing method, after degreasing, the tungsten alloy busbar first enters the hot water washing tank, the water temperature is 50-70℃, the time is 1-5S, and then passes through the cold water washing tank; Step C: Activate the surface of the tungsten alloy busbar with concentrated hydrochloric acid or hydrofluoric acid at a temperature of 10-30°C for 1-5 seconds, and then wash with water for activation.

9. The method for preparing tungsten alloy wire according to claim 7, characterized in that: The process of electroplating the pre-plating layer in step 2 is: the current density is 4-20A / dm 2 , the electroplating time is 1-30S; the anode is a lead-tin alloy or a platinum-iridium anode; the electroplating solution composition is chromic anhydride: 100-400g / L, sulfuric acid 1-5g / L, La 3+ : 0.1-2.5g / L.

10. The method for preparing tungsten alloy wire according to claim 7, characterized in that: The process of electroplating the composite coating in step 2 is as follows: the electroplating solution composition is 250g / L of one or more of metal oxides, metal halides, metal sulfides, metal selenides, 100g / L of sulfuric acid, and 0.1-100g / L of solid lubricant; the current density is 8-10A / dm 2 .

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