Tungsten alloy wire and diamond wire saw made thereof, as well as preparation method and application thereof

Abstract

The preparation method of the present invention comprises the following steps: (1) preparation of alloy tungsten wire busbar, raw material → reduction → doping → reduction → isostatic pressing → sintering → vertical melting → rotary forging → annealing → wire drawing → electrolysis, to obtain 30-50 μm silver-white metallic luster alloy tungsten wire; (2) the alloy tungsten wire obtained in step (1) is subjected to the following steps: wire laying → pre-treatment → impact plating → sanding → sand consolidation → post-treatment → wire winding, to obtain alloy tungsten wire diamond wire saw. (3) the alloy tungsten wire diamond wire saw obtained in step (2) is used in conjunction with the customer's cutting technology, the cutting technology mainly comprising the optimization of guide wheel parameters, the adjustment of cutting fluid pH, the cutting tension, etc. The alloy tungsten wire busbar provided by the present invention has the advantages of finer specifications, higher strength, low brittle fracture frequency, good conductivity, corrosion resistance, etc., which greatly reduces the wire breakage rate in the production process and the customer application end, and can achieve the advantages of low wire breakage, high cutting efficiency, and good silicon wafer quality.

Description

Technical Field

[0001] The present invention belongs to the field of wire saw cutting, and in particular relates to a tungsten alloy wire and a diamond wire saw made of the same, as well as a preparation method and application thereof. Background Art

[0002] Diamond wire saws are made by bonding diamonds to the surface of the busbar. They have the characteristics of high cutting efficiency and excellent cutting quality. Diamond wire saws are widely used in wire cutting industries such as photovoltaic silicon wafers, semiconductors, sapphire, and magnetic materials.

[0003] As far as the application field of diamond wire is concerned, the manufacturing cost of tungsten busbar is 2 to 3 times that of carbon steel of the same specification, which hinders its market promotion due to its high cost; the preparation of single-doped Re or La alloy tungsten wire has been reported in the literature, but because its strength or toughness is not significantly improved, its industrialization has not been reported in the field of silicon wafer cutting.

[0004] At the same time, with the development of the photovoltaic silicon wafer diamond wire saw industry, silicon wafer cutting is moving towards thinner wires and larger wafers to meet customer demands for higher wafer output, higher wafer quality, and higher efficiency. Consequently, demands for diamond wire saws have been placed on them, including finer diameters, higher strength, improved toughness, more uniform diamonds, and fewer wire breakages. Currently, mass-produced diamond wire saws primarily use 92% or 100% carbon raw materials as carriers. However, due to the decreasing diameter, carbon steel raw materials cannot meet industry demands due to defects such as inclusions, rough grains, and insufficient strength. Therefore, the search for alternative wire materials is crucial for diamond wire saw cutting. Summary of the Invention

[0005] In order to overcome the deficiencies in the prior art, the present invention aims to provide a tungsten alloy wire and a diamond wire saw made thereof, as well as a preparation method and application thereof. The specific technical solutions are as follows:

[0006] A tungsten alloy wire is doped with 0.03-20% Re and / or 0.01-15% La by mass. The tungsten alloy wire has a diameter of 30-50 μm, a strength of ≥5100 MPa, and an elastic modulus of 350-450 GPa.

[0007] Preferably, the tungsten filament is doped with 3-20% by mass of Re and / or 2.5-15% by mass of La;

[0008] A method for preparing tungsten alloy wire comprises the following steps:

[0009] Step 1: After the raw tungsten powder is reduced with hydrogen, it is pickled and impurities are removed to obtain tungsten powder with a purity of ≥99%;

[0010] Step 2: spraying rhenium nitrate and lanthanum nitrate solutions onto the tungsten powder obtained in step 1 and stirring and mixing them so that the doping amount of Re is 0.03 to 20 wt% and / or La is 0.01 to 15 wt%;

[0011] Step 3: The mixed tungsten powder obtained in step 2 is subjected to a primary hydrogen reduction in a 700°C hydrogen reduction furnace and a secondary hydrogen reduction in a 850°C hydrogen reduction furnace to obtain a mixed alloy tungsten powder. Preferably, the concentration of hydrogen used in the two reductions is not less than 99%;

[0012] Step 4: isostatically press the mixed alloy tungsten powder obtained in step 3 to obtain a powder with a density of 8.0 to 15 g / cm 3 , semi-finished products with forming strength;

[0013] Step 5: pre-sinter the semi-finished product obtained in step 4 at a sintering temperature of 1200° C. for 45 to 65 minutes, and then perform vertical melting sintering at a sintering temperature of 2900° C. for 110 to 130 minutes;

[0014] Step 6: The product obtained in step 5 is subjected to rotary forging to form a blank, and then annealed in a hydrogen protection heating furnace at an annealing temperature of 1100° C.

[0015] Step 7: The product obtained in Step 6 is continuously swaged to produce a 2-3 mm diameter tungsten alloy rod. Graphite emulsion is evenly coated on the rod surface, and the rod is then drawn through a diamond die to produce a 30-50 μm diameter tungsten alloy wire. Preferably, the wire is drawn through 36 passes to produce a 30-50 μm diameter tungsten alloy wire.

[0016] Furthermore, the pickling and impurity removal in step 1 uses a mixed solution of aminosulfonic acid and hydrochloric acid, wherein the concentration of aminosulfonic acid is 50g / L and the concentration of hydrochloric acid is 60ml / L, so as to improve the adsorption uniformity of the tungsten powder to the doping element.

[0017] Preferably, the doping amount in step 2 is 3-20 wt% Re and / or 2.5-15 wt% La.

[0018] Preferably, the parameter of the isostatic pressing in step 3 is 150-230 MPa, and the pressing is maintained for 30-60 minutes.

[0019] Furthermore, in step 7, the diamond mold adopts a 7.5° small-angle diamond mold, the purpose of which is to reduce the compression ratio of the steel wire, improve the residual stress of the steel wire, and make the tissue deformation more uniform; the graphite emulsion adopts D50=0.2um nano-graphite powder, which can make the lubrication performance more uniform, reduce damage to the mold and avoid the generation of drawing groove defects.

[0020] A diamond wire saw made from the aforementioned tungsten alloy wire comprises, from the inside out, a tungsten alloy busbar, a pre-nickel plating layer, a sanding nickel layer, and a sand-fixing nickel layer. The wire has a diameter of 45 to 65 μm, a breaking strength of 6.5 to 11 N, excellent flexibility, and a bending failure rate of 0 times per 10 cycles. It also exhibits good corrosion resistance, passing a 72-hour salt spray test and achieving a Class 10 rating. This high-cutting-force diamond wire saw can achieve a single-wafer wire consumption of 0.9 to 2.2 m per silicon wafer. The pre-nickel plating layer has a thickness of 30 to 500 nm, enhancing its coverage and satisfying the magnetic properties required for sanding, effectively improving the sanding capability of the alloy tungsten busbar during the electroplating process.

[0021] A method for preparing the aforementioned diamond wire saw comprises the following steps:

[0022] Step 1: After the tungsten alloy wire is paid out, it is first treated with a 60g / L NaOH solution for 6 seconds; then treated with a 50g / L sulfamic acid solution for 3.5 seconds;

[0023] Step 2: impact plating, the impact plating is nickel sulfamate electroplating, Ni is 90g / L, boric acid is 35g / L, nickel chloride is 8g / L, the current density is 7ASD, and the impact plating layer thickness is 100nm;

[0024] Step 3: Sanding: The sanding is nickel sulfamate electroplating, with Ni of 100 g / L, boric acid of 30 g / L, nickel chloride of 6 g / L, current density of 9 ASD, diamond D50 particle size of 7.2 μm and diamond concentration of 2.0 g / L in the sanding plating solution;

[0025] Step 4: consolidation, the consolidation is nickel sulfamate electroplating, Ni is 110g / L, boric acid is 35g / L, nickel chloride is 8g / L, and the current density is 9.5ASD;

[0026] Step 5: Post-processing, which includes washing with pure water at room temperature, drying at 180°C, and winding to obtain a diamond wire saw with a wire diameter of 45 to 65 μm.

[0027] Furthermore, graphite emulsion exists on the surface of the alloy tungsten wire after doping, and its presence will affect the bonding strength of the coating. In step 1, electrolysis is adopted, and the steel wire is used as the anode to dissolve the metal on the surface so that the graphite attached thereto loses its carrier and detaches, exposing the fresh substrate, thereby enhancing the bonding strength between nickel and tungsten atoms and enhancing the bonding strength between the coating and the alloy tungsten wire.

[0028] A method for using a diamond wire saw comprises: rewinding a tungsten alloy wire saw under a tension of 3.5 to 6.0 N onto a slotted guide wheel to form a densely wired network running at a speed of 600 to 2100 m / min; pressing a silicon rod to be cut into the densely wired network at a table speed of 200 to 2100 mm / min under cooling with a cutting fluid; and utilizing the diamond cutting force of the tungsten alloy wire saw to cut the silicon rod into silicon wafers of uniform thickness; the wire network length is 4.5 to 8.0 km, and the slotted guide wheel length is 4.5 to 8.0 km. The diameter is 190-210 mm, the groove angle is 20-40°, the guide wheel groove depth is 150-240 μm, and the guide wheel groove R angle is 20-45°; the cutting fluid is a high COD (surfactant, corrosion inhibitor, dispersant, detergent and other high molecular organic matter) cutting water solution, and its pH is controlled at 3.5-6.5. The cutting process table speed range is 200-2100 mm / min, and the line speed range is 600-2100 m / min.

[0029] Preferably, the slotted guide wheel is a two-axis or three-axis one.

[0030] This invention utilizes the mechanisms of dispersion strengthening and solid solution strengthening in metal structures. By doping with rare earth elements such as Re and La, the size of metal precipitation grains is reduced, resulting in a denser structure. This comprehensively improves the strength and plasticity of the tungsten filament, resulting in high tensile strength and flexibility at a thin diameter. Graphite emulsions are present on the surface of the alloy tungsten filament after doping, which can affect the adhesion of the coating. During production, electrolysis is used, using steel wire as the anode to dissolve the metal on the surface, causing the attached graphite to lose its support and detach, exposing a fresh substrate. This strengthens the bonding strength between the nickel and tungsten atoms, and enhances the adhesion between the coating and the alloy tungsten filament.

[0031] This invention utilizes alloy tungsten wire as a carrier, doped with Re and La to achieve high strength, corrosion resistance, and low brittle fracture rates. Furthermore, the impact plating thickness is optimized in the diamond wire saw production process to improve sanding capacity. Furthermore, a cutting process with appropriate guide wheel parameters, low cutting fluid pH, and high cutting tension has been developed. This meets customer needs for thin wire, low wire breakage rates, high wafer quality, and high efficiency. This results in lower wire consumption per blade, higher cutting efficiency, lower average TTV, and reduced short wire rates. This invention is applicable to wire cutting industries for photovoltaic silicon wafers, semiconductors, sapphire, magnetic materials, and other materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A flow chart of the manufacturing process of a diamond wire saw made of tungsten alloy wire of the present invention;

[0033] Figure 2 This is a schematic diagram of a diamond wire saw punching pre-nickel plating layer according to the present invention;

[0034] Figure 3 This is a schematic diagram of the guide wheel parameters for the alloy tungsten wire diamond wire saw cutting technology of the present invention. DETAILED DESCRIPTION

[0035] The embodiments illustrate the method of the present invention. It should be understood that these embodiments are only used to explain the present invention and are not intended to limit the scope of the present invention. It should be understood that after reading the contents of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims appended hereto.

[0036] The raw materials used in the following examples can be purchased from the market.

[0037] Comparative Example

[0038] The invention discloses an ultrafine high-strength alloy tungsten wire diamond wire saw, which is composed of an alloy tungsten wire busbar and a metal-consolidated diamond with a nickel layer on the surface. The busbar is an alloy tungsten wire doped with Al, As, and Ga elements, the nickel plating is a nickel sulfamate system, and the diamond D50 particle size is 7.2 μm.

[0039] Preparation of alloy tungsten wire busbar:

[0040] 1. After the raw tungsten powder is reduced with hydrogen once, it is doped with Al, As, and Ga oxides and stirred and mixed in a mass ratio of 7:65:1, and the mass of the mixture is added to the total mass ratio of 0.1-0.3%.

[0041] 2. The tungsten powder doped in step 1 is reduced in a 700°C hydrogen reduction furnace, and then reduced again in a 850°C hydrogen reduction furnace. After acid washing and mixing, mixed alloy tungsten powder is obtained.

[0042] 3. The mixed powder obtained in step 2 is isostatically pressed to obtain a semi-finished product with a certain density and strength.

[0043] 4. The semi-finished product of step 3 is pre-sintered at a sintering temperature of 1200°C, and then vertical melting sintered at a sintering temperature of 2900°C.

[0044] 5. The sample in step 4 was rotary forged and then annealed in a hydrogen-protected heating furnace at a temperature of 1100°C.

[0045] 6. The sample obtained in step 5 is continuously swaged to obtain the desired diameter for wire drawing. The wire drawing die is a diamond die, and the wire drawing lubricant is graphite emulsion. Black wire with graphite emulsion attached to the surface is obtained, and its diameter is 44 μm.

[0046] 7. The 44 μm tungsten alloy wire sample obtained in step 6 was electrolyzed in an electrolyte of 100 g / L NAOH to obtain a 43 μm white alloy tungsten wire with a diameter of 43 ± 0.5 μm, a breaking tensile force ≥ 7.3 N, and an elastic modulus of 332 GPa.

[0047] Preparation of alloy tungsten diamond wire:

[0048] (1) The above alloy tungsten wire busbar is laid out and pre-treated for surface cleaning. The pre-treatment includes a NaOH alkali solution station with a concentration of 60g / L and a treatment time of 6s; the pre-treatment includes a sulfamic acid solution station with a concentration of 50g / L and a treatment time of 3.5s.

[0049] (2) Impact plating, wherein the impact plating is nickel sulfamate electroplating, wherein Ni is 90 g / L, boric acid is 35 g / L, nickel chloride is 8 g / L, current density is 7 ASD, and the impact plating layer thickness is 100 nm.

[0050] (3) Plating the plating solution using nickel sulfamate electroplating, with a nickel content of 100 g / L, a boric acid content of 30 g / L, and a nickel chloride content of 6 g / L at a current density of 9 ASD. The diamond D50 particle size in the plating solution was 7.2 μm, and the diamond concentration was 2.0 g / L.

[0051] (4) Consolidation, wherein the consolidation is nickel sulfamate electroplating, with Ni being 110 g / L, boric acid being 35 g / L, nickel chloride being 8 g / L, and a current density being 9.5 ASD.

[0052] (5) Post-processing, including a normal temperature pure water washing station and a drying station, with a drying temperature of 180°C. After winding, a 43 μm alloy tungsten diamond wire saw is obtained, with uniform sanding, a breaking force of ≥8.1N, a brittle fracture frequency of 0.2 times, and a knotted breaking force accounting for ≥30% of the total breaking force.

[0053] Tungsten alloy diamond wire cutting application: Cutting 210 silicon ingots, involving cutting processes such as: cutting tension of 5.6N, cutting tension ratio ≥ 63%, cutting guide wheel groove depth of 240μm, guide wheel R angle of 30°, cutting fluid pH = 5.0, cutting fluid supply volume of 1.7L. Single-cut wire consumption is reduced by 10%, wire breakage rate is reduced to <2.0%, and average silicon wafer TTV is ≤ 10μm.

[0054] Example 1

[0055] An ultrafine high-strength alloy tungsten wire diamond wire saw consists of an alloy tungsten wire busbar and a surface nickel layer of metal-consolidated diamond. The busbar is a Re-doped alloy tungsten wire, the nickel plating is a nickel sulfamate system, and the diamond D50 particle size is 7.2 μm.

[0056] Preparation of alloy tungsten wire busbar:

[0057] (1) The raw tungsten powder was reduced with hydrogen once, and then doped with rhenium nitrate and stirred to make the doping amount Re be 10.17 wt%.

[0058] (2) The tungsten powder doped in step (1) is reduced in a 700° C. hydrogen reduction furnace, and then reduced again in a 850° C. hydrogen reduction furnace, and then pickled and mixed to obtain mixed alloy tungsten powder.

[0059] (3) isostatically pressing the mixed powder obtained in step (2) to obtain a semi-finished product with a certain density and strength.

[0060] (4) The semi-finished product obtained in step (3) is pre-sintered at a sintering temperature of 1200°C, and then subjected to vertical melting sintering at a sintering temperature of 2900°C.

[0061] (5) The sample obtained in step (4) was subjected to rotary forging to form a blank, and then annealed in a hydrogen protection heating furnace at an annealing temperature of 1100°C.

[0062] (6) The sample obtained in step (5) is continuously swaged to obtain the desired diameter for wire drawing. The wire drawing die is a diamond die, and the wire drawing lubricant is graphite emulsion. A black alloy tungsten wire (hereinafter referred to as black wire) with graphite emulsion attached to the surface is obtained, and its diameter is 44 μm.

[0063] (7) The 44 μm black wire sample obtained in step (6) was subjected to electrolysis treatment, wherein the electrolyte was NAOH with a concentration of 100 g / L to obtain a 43 μm white alloy tungsten wire (hereinafter referred to as white wire) with a diameter of 43 ± 0.5 μm, a breaking tensile force ≥ 7.5 N, and an elastic modulus of 352 GPa.

[0064] Preparation of alloy tungsten diamond wire:

[0065] (1) The alloy tungsten wire busbar is laid out and pre-treated for surface cleaning. The pre-treatment includes a NaOH alkali solution station with a concentration of 60g / L and a treatment time of 6s; the pre-treatment includes a sulfamic acid solution station with a concentration of 50g / L and a treatment time of 3.5s.

[0066] (2) Impact plating, wherein the impact plating is nickel sulfamate electroplating, wherein Ni is 90 g / L, boric acid is 35 g / L, nickel chloride is 8 g / L, current density is 7 ASD, and the impact plating layer thickness is 100 nm.

[0067] (3) Plating the plating solution using nickel sulfamate electroplating, with a nickel content of 100 g / L, a boric acid content of 30 g / L, and a nickel chloride content of 6 g / L at a current density of 9 ASD. The diamond D50 particle size in the plating solution was 7.2 μm, and the diamond concentration was 2.0 g / L.

[0068] (4) Consolidation, wherein the consolidation is nickel sulfamate electroplating, with Ni being 110 g / L, boric acid being 35 g / L, nickel chloride being 8 g / L, and a current density being 9.5 ASD.

[0069] (5) Post-processing, including a normal temperature pure water washing station and a drying station, with a drying temperature of 180°C. After winding, a 43 μm tungsten alloy diamond wire saw is obtained, which is evenly sanded, has a breaking force of ≥8.2N, a brittle fracture frequency of 0, and a knotted breaking force accounting for ≥45% of the total breaking force.

[0070] Cutting process application of alloy tungsten diamond wire:

[0071] The cutting process for 210mm silicon ingots involves the following: cutting tension of 5.6N, cutting tension ratio ≥ 63%, cutting guide wheel groove depth of 240μm, guide wheel R angle of 30°, cutting fluid pH of 5.0, and cutting fluid supply of 1.7L. This reduces single-blade wire consumption by 10%, wire breakage rate to <2.0%, and average wafer TTV ≤ 10μm.

[0072] Example 2

[0073] An ultrafine high-strength alloy tungsten wire diamond wire saw consists of an alloy tungsten wire busbar and a surface nickel layer of metal-consolidated diamond. The busbar is a La-doped alloy tungsten wire, the nickel plating is a nickel sulfamate system, and the diamond D50 particle size is 7.2 μm.

[0074] Preparation of alloy tungsten wire busbar:

[0075] (1) The raw tungsten powder was reduced with hydrogen once, and then doped with lanthanum nitrate and stirred to make the doping amount La be 13.32 wt%.

[0076] (2) The tungsten powder doped in step (1) is reduced in a 700° C. hydrogen reduction furnace, and then reduced again in a 850° C. hydrogen reduction furnace, and then pickled and mixed to obtain mixed alloy tungsten powder.

[0077] (3) isostatically pressing the mixed powder obtained in step (2) to obtain a semi-finished product with a certain density and strength.

[0078] (4) The semi-finished product obtained in step (3) is pre-sintered at a sintering temperature of 1200°C, and then subjected to vertical melting sintering at a sintering temperature of 2900°C.

[0079] (5) The sample obtained in step (4) was subjected to rotary forging to form a blank, and then annealed in a hydrogen protection heating furnace at an annealing temperature of 1100°C.

[0080] (6) The sample obtained in step (5) is continuously swaged to obtain the desired diameter for wire drawing. The wire drawing die is a diamond die, and the wire drawing lubricant is graphite emulsion. A black tungsten alloy wire with graphite emulsion attached to the surface is obtained, and the diameter of the wire is 44 μm.

[0081] (7) The 44 μm black wire sample obtained in step (6) was subjected to electrolysis treatment, wherein the electrolyte was NaOH with a concentration of 100 g / L to obtain a 43 μm white alloy tungsten wire with a diameter of 43±0.5 μm, a breaking tensile force ≥7.8 N, and an elastic modulus of 410 GPa.

[0082] Preparation of alloy tungsten diamond wire:

[0083] (1) The alloy tungsten wire busbar is laid out and pre-treated for surface cleaning. The pre-treatment includes a NaOH alkali solution station with a concentration of 60g / L and a treatment time of 6s; the pre-treatment includes a sulfamic acid solution station with a concentration of 50g / L and a treatment time of 3.5s.

[0084] (2) Impact plating, wherein the impact plating is nickel sulfamate electroplating, wherein Ni is 90 g / L, boric acid is 35 g / L, nickel chloride is 8 g / L, current density is 7 ASD, and the impact plating layer thickness is 100 nm.

[0085] (3) Plating the plating solution using nickel sulfamate electroplating, with a nickel content of 100 g / L, a boric acid content of 30 g / L, and a nickel chloride content of 6 g / L at a current density of 9 ASD. The diamond D50 particle size in the plating solution was 7.2 μm, and the diamond concentration was 2.0 g / L.

[0086] (4) Consolidation, wherein the consolidation is nickel sulfamate electroplating, with Ni being 110 g / L, boric acid being 35 g / L, nickel chloride being 8 g / L, and a current density being 9.5 ASD.

[0087] (5) Post-processing, including a normal temperature pure water washing station and a drying station, with a drying temperature of 180°C. After winding and coiling, a 43 μm alloy tungsten diamond wire saw is obtained, with uniform sanding, a breaking force of ≥8.5N, 0 brittle fracture times, and a knotted breaking force accounting for ≥45% of the total breaking force.

[0088] Tungsten alloy diamond wire cutting application: Cutting 210 silicon ingots, involving cutting processes such as: cutting tension of 5.6N, cutting tension ratio ≥ 63%, cutting guide wheel groove depth of 240μm, guide wheel R angle of 30°, cutting fluid pH = 5.0, and cutting fluid supply volume of 1.7L. Single-cut wire consumption is reduced by 13%, wire breakage rate is reduced to <1.5%, and average wafer TTV is ≤ 10μm.

[0089] Example 3

[0090] An ultrafine high-strength alloy tungsten wire diamond wire saw consists of an alloy tungsten wire busbar and a surface nickel layer of metal-consolidated diamond. The busbar is a tungsten wire alloy doped with Re and La elements, the nickel plating is a nickel sulfamate system, and the diamond D50 particle size is 7.2μm.

[0091] Preparation of alloy tungsten wire busbar:

[0092] (1) The raw tungsten powder was reduced with hydrogen once, and then doped with rhenium nitrate and lanthanum nitrate, and stirred and mixed to make the doping amount Re be 10.17 wt% and La be 13.32 wt%.

[0093] (2) The tungsten powder doped in step (1) is reduced in a 700° C. hydrogen reduction furnace, and then reduced again in a 850° C. hydrogen reduction furnace, and then pickled and mixed to obtain mixed alloy tungsten powder.

[0094] (3) isostatically pressing the mixed powder obtained in step (2) to obtain a semi-finished product with a certain density and strength.

[0095] (4) The semi-finished product obtained in step (3) is pre-sintered at a sintering temperature of 1200°C, and then subjected to vertical melting sintering at a sintering temperature of 2900°C.

[0096] (5) The sample obtained in step (4) was subjected to rotary forging to form a blank, and then annealed in a hydrogen protection heating furnace at an annealing temperature of 1100°C.

[0097] (6) The sample obtained in step (5) is continuously swaged to obtain the desired diameter for wire drawing. The wire drawing die is a diamond die, and the wire drawing lubricant is graphite emulsion. A black alloy tungsten wire with graphite emulsion attached to the surface is obtained, and the diameter is 44 μm.

[0098] (7) The 44 μm black wire sample obtained in step (6) was subjected to electrolysis treatment, wherein the electrolyte was NAOH with a concentration of 100 g / L to obtain a 43 μm white wire alloy tungsten wire with a diameter of 43±0.5 μm, a breaking tensile force ≥7.9 N, and an elastic modulus of 420 GPa.

[0099] Preparation of diamond wire:

[0100] (1) The alloy tungsten wire busbar is laid out and pre-treated for surface cleaning. The pre-treatment includes a NAOH alkali solution station with a concentration of 60g / L and a treatment time of 6s; the pre-treatment includes a sulfamic acid solution station with a concentration of 50g / L and a treatment time of 3.5s.

[0101] (2) Impact plating, wherein the impact plating is nickel sulfamate electroplating, wherein Ni is 90 g / L, boric acid is 35 g / L, nickel chloride is 8 g / L, current density is 7 ASD, and the impact plating layer thickness is 100 nm.

[0102] (3) Plating the plating solution using nickel sulfamate electroplating, with a nickel content of 100 g / L, a boric acid content of 30 g / L, and a nickel chloride content of 6 g / L at a current density of 9 ASD. The diamond D50 particle size in the plating solution was 7.2 μm, and the diamond concentration was 2.0 g / L.

[0103] (4) Consolidation, wherein the consolidation is nickel sulfamate electroplating, with Ni being 110 g / L, boric acid being 35 g / L, nickel chloride being 8 g / L, and a current density being 9.5 ASD.

[0104] (5) Post-processing, including a normal temperature pure water washing station and a drying station, with a drying temperature of 180°C. After winding and coiling, a 43 μm alloy tungsten diamond wire saw is obtained, with uniform sanding, a breaking force of ≥8.8N, 0 brittle fracture times, and a knotted breaking force accounting for ≥45% of the total breaking force.

[0105] Tungsten alloy diamond wire cutting applications: Cutting 210 silicon ingots, using the following cutting process: cutting tension of 5.6N, cutting tension ratio ≥ 63%, cutting guide wheel groove depth of 240μm, guide wheel R angle of 30°, cutting fluid pH = 5.0, and cutting fluid supply volume of 1.7L. Single-cut wire consumption is reduced by 15%, wire breakage rate is reduced to <1%, and average wafer TTV is ≤ 10μm.

[0106] Example 4

[0107] An ultrafine high-strength alloy tungsten wire diamond wire saw consists of an alloy tungsten wire busbar and a surface nickel layer of metal-consolidated diamond. The busbar is a tungsten wire alloy doped with Re and La elements, the nickel plating is a nickel sulfamate system, and the diamond D50 particle size is 6.5μm.

[0108] Preparation of alloy tungsten wire busbar:

[0109] (1) The raw tungsten powder was reduced with hydrogen once, and then doped with rhenium nitrate and lanthanum nitrate, and stirred and mixed to make the doping amount Re be 10.17 wt% and La be 13.32 wt%.

[0110] (2) The tungsten powder doped in step (1) is reduced in a 700° C. hydrogen reduction furnace, and then reduced again in a 850° C. hydrogen reduction furnace, and then pickled and mixed to obtain mixed alloy tungsten powder.

[0111] (3) isostatically pressing the mixed powder obtained in step (2) to obtain a semi-finished product with a certain density and strength.

[0112] (4) The semi-finished product of step (3) is pre-sintered at a sintering temperature of 1200°C, and then subjected to vertical melting sintering at a sintering temperature of 2900°C.

[0113] (5) The sample obtained in step (4) was subjected to rotary forging to form a blank, and then annealed in a hydrogen protection heating furnace at an annealing temperature of 1100°C.

[0114] (6) The sample obtained in step (5) is continuously swaged to obtain the desired diameter for wire drawing. The wire drawing die is a diamond die, and the wire drawing lubricant is graphite emulsion. Black wire with graphite emulsion attached to the surface is obtained, and its diameter is 41 μm.

[0115] (7) The 41 μm black wire sample obtained in step (6) was subjected to electrolysis treatment, wherein the electrolyte was NAOH with a concentration of 100 g / L to obtain a 40 μm white wire alloy tungsten wire with a diameter of 40±0.5 μm, a breaking tensile force ≥7.0 N, and an elastic modulus of 371 GPa.

[0116] Preparation of alloy tungsten diamond wire:

[0117] (1) The alloy tungsten wire busbar is laid out and pre-treated for surface cleaning. The pre-treatment includes a NAOH alkali solution station with a concentration of 40g / L and a treatment time of 6s; the pre-treatment includes a sulfamic acid solution station with a concentration of 40g / L and a treatment time of 3.5s.

[0118] (2) Impact plating, wherein the impact plating is nickel sulfamate electroplating, wherein Ni is 90 g / L, boric acid is 35 g / L, nickel chloride is 8 g / L, current density is 6.5 ASD, and the impact plating layer thickness is 90 nm.

[0119] (3) Plating the plating solution using nickel sulfamate electroplating, with a nickel content of 100 g / L, a boric acid content of 30 g / L, a nickel chloride content of 6 g / L, and a current density of 8.0 ASD. The diamond D50 particle size in the plating solution was 6.5 μm, and the diamond concentration was 1.8 g / L.

[0120] (4) Consolidation, wherein the consolidation is nickel sulfamate electroplating, with Ni being 110 g / L, boric acid being 35 g / L, nickel chloride being 8 g / L, and a current density being 8.0 ASD.

[0121] (5) Post-processing, including a normal temperature pure water washing station and a drying station, with a drying temperature of 180°C. After winding and coiling, a 40 μm alloy tungsten diamond wire saw is obtained, which is evenly sanded, has a breaking force of ≥7.8N, a brittle fracture frequency of 0, and a knotted breaking force accounting for ≥43% of the total breaking force.

[0122] Tungsten alloy diamond wire cutting applications: Cutting 210 silicon ingots, using the following cutting process: cutting tension of 4.7N, cutting tension ratio ≥ 60%, cutting guide wheel groove depth of 240μm, guide wheel R angle of 28°, cutting fluid pH of 5.0, and cutting fluid supply of 1.7L. Single-cut wire consumption was reduced by 12%, wire breakage rate was reduced to <1.5%, and average wafer TTV was ≤10μm.

[0123] Example 5

[0124] An ultrafine high-strength alloy tungsten wire diamond wire saw consists of an alloy tungsten wire busbar and a surface nickel layer of metal-consolidated diamond. The busbar is a tungsten wire alloy doped with Re and La elements, the nickel plating is a nickel sulfamate system, and the diamond D50 particle size is 7.5μm.

[0125] Preparation of alloy tungsten wire busbar:

[0126] (1) The raw tungsten powder was reduced with hydrogen once, and then doped with rhenium nitrate and lanthanum nitrate, and stirred and mixed to make the doping amount Re be 10.17 wt% and La be 13.32 wt%.

[0127] (2) The tungsten powder doped in step (1) is reduced in a 700° C. hydrogen reduction furnace, and then reduced again in a 850° C. hydrogen reduction furnace, and then pickled and mixed to obtain mixed alloy tungsten powder.

[0128] (3) isostatically pressing the mixed powder obtained in step (2) to obtain a semi-finished product with a certain density and strength.

[0129] (4) The semi-finished product of step (3) is pre-sintered at a sintering temperature of 1200°C, and then subjected to vertical melting sintering at a sintering temperature of 2900°C.

[0130] (5) The sample obtained in step (4) was subjected to rotary forging to form a blank, and then annealed in a hydrogen protection heating furnace at an annealing temperature of 1100°C.

[0131] (6) The sample obtained in step (5) is continuously swaged to obtain the desired diameter for wire drawing. The wire drawing die is a diamond die, and the wire drawing lubricant is graphite emulsion. Black wire with graphite emulsion attached to the surface is obtained, and its diameter is 38 μm.

[0132] (7) The 38 μm black wire sample obtained in step (6) was subjected to electrolysis treatment, wherein the electrolyte was NAOH with a concentration of 100 g / L to obtain a 37 μm white alloy tungsten wire with a diameter of 37±0.5 μm, a breaking tensile force ≥6.2 N, and an elastic modulus of 356 GPa.

[0133] Preparation of alloy tungsten diamond wire:

[0134] (1) The alloy tungsten wire busbar is laid out and pre-treated for surface cleaning. The pre-treatment includes a NAOH alkali solution station with a concentration of 40g / L and a treatment time of 4.5s; the pre-treatment includes a sulfamic acid solution station with a concentration of 40g / L and a treatment time of 3.0s.

[0135] (2) Impact plating, wherein the impact plating is nickel sulfamate electroplating, wherein Ni is 90 g / L, boric acid is 35 g / L, nickel chloride is 8 g / L, current density is 7.5 ASD, and the impact plating layer thickness is 160 nm.

[0136] (3) Plating the plating solution using nickel sulfamate electroplating, with a nickel content of 100 g / L, a boric acid content of 30 g / L, a nickel chloride content of 6 g / L, and a current density of 6.7 ASD. The diamond D50 particle size in the plating solution was 6.5 μm, and the diamond concentration was 1.5 g / L.

[0137] (4) Consolidation, wherein the consolidation is nickel sulfamate electroplating, with Ni being 110 g / L, boric acid being 35 g / L, nickel chloride being 8 g / L, and a current density being 7.5 ASD.

[0138] (5) Post-processing, including a normal temperature pure water washing station and a drying station, with a drying temperature of 180°C. After winding and coiling, a 37 μm alloy tungsten diamond wire saw is obtained, with uniform sanding, a breaking force of ≥6.9N, 0 brittle fracture times, and a knotted breaking force accounting for ≥38% of the total breaking force.

[0139] Cutting process application of alloy tungsten diamond wire:

[0140] The cutting process for 182-mm silicon ingots involves the following: cutting tension of 4.1N, cutting tension ratio ≥53%, cutting guide wheel groove depth of 240μm, guide wheel R angle of 25°, cutting fluid pH of 5.0, and cutting fluid supply of 1.7L. This reduces single-blade wire consumption by 10%, wire breakage rate to <1.5%, and average wafer TTV ≤10μm.

[0141] Example 6

[0142] An ultrafine high-strength alloy tungsten wire diamond wire saw consists of an alloy tungsten wire busbar and a surface nickel layer of metal-consolidated diamond. The busbar is a tungsten wire alloy doped with Re and La elements, the nickel plating is a nickel sulfamate system, and the diamond D50 particle size is 7.2μm.

[0143] Preparation of alloy tungsten wire busbar:

[0144] (1) The raw tungsten powder was reduced with hydrogen once, and then doped with rhenium nitrate and lanthanum nitrate, and stirred and mixed to make the doping amount Re be 3 wt% and La be 15 wt%.

[0145] (2) The tungsten powder doped in step (1) is reduced in a 700° C. hydrogen reduction furnace, and then reduced again in a 850° C. hydrogen reduction furnace, and then pickled and mixed to obtain mixed alloy tungsten powder.

[0146] (3) isostatically pressing the mixed powder obtained in step (2) to obtain a semi-finished product with a certain density and strength.

[0147] (4) The semi-finished product of step (3) is pre-sintered at a sintering temperature of 1200°C, and then subjected to vertical melting sintering at a sintering temperature of 2900°C.

[0148] (5) The sample prepared in step (4) was subjected to rotary forging and then annealed in a hydrogen-protected heating furnace at a temperature of 1100°C.

[0149] (6) The sample from step (5) is continuously swaged to obtain the desired diameter for wire drawing. The wire drawing die is a diamond die, and the wire drawing lubricant is graphite emulsion. Black wire with graphite emulsion attached to the surface is obtained, and the diameter of the black wire is 44 μm.

[0150] (7) The 44 μm black wire sample in step (6) was electrolyzed, wherein the electrolyte was NAOH with a concentration of 100 g / L, to obtain a 43 μm white tungsten alloy wire with a diameter of 43 ± 0.5 μm, a breaking tensile force ≥ 7.7 N, and an elastic modulus of 375 GPa.

[0151] Preparation of diamond wire:

[0152] (1) The alloy tungsten wire busbar is laid out and pre-treated for surface cleaning. The pre-treatment includes a NaOH alkali solution station with a concentration of 60g / L and a treatment time of 6s; the pre-treatment includes a sulfamic acid solution station with a concentration of 50g / L and a treatment time of 3.5s.

[0153] (2) Impact plating, wherein the impact plating is nickel sulfamate electroplating, wherein Ni is 90 g / L, boric acid is 35 g / L, nickel chloride is 8 g / L, current density is 7 ASD, and the impact plating layer thickness is 100 nm.

[0154] (3) Plating the plating solution using nickel sulfamate electroplating, with a nickel content of 100 g / L, a boric acid content of 30 g / L, and a nickel chloride content of 6 g / L at a current density of 9 ASD. The diamond D50 particle size in the plating solution was 7.2 μm, and the diamond concentration was 2.0 g / L.

[0155] (4) Consolidation, wherein the consolidation is nickel sulfamate electroplating, with Ni being 110 g / L, boric acid being 35 g / L, nickel chloride being 8 g / L, and a current density being 9.5 ASD.

[0156] (5) Post-processing, including a normal temperature pure water washing station and a drying station, with a drying temperature of 180°C. After winding and reeling, a 43 μm alloy tungsten diamond wire saw is obtained, with uniform sanding, a breaking force of ≥8.5N, 0 brittle fracture times, and a knotted breaking force accounting for ≥42% of the total breaking force.

[0157] Tungsten alloy diamond wire cutting applications: Cutting 210 silicon ingots, using the following cutting process: cutting tension of 5.6N, cutting tension ratio ≥ 66.6%, cutting guide wheel groove depth of 240μm, guide wheel R angle of 30°, cutting fluid pH of 5.0, and cutting fluid supply of 1.7L. Single-cut wire consumption was reduced by 10%, wire breakage rate was reduced to <1.5%, and average wafer TTV was ≤11μm.

[0158] Example 7

[0159] An ultrafine high-strength alloy tungsten wire diamond wire saw consists of an alloy tungsten wire busbar and a surface nickel layer of metal-consolidated diamond. The busbar is a tungsten wire alloy doped with Re and La elements, the nickel plating is a nickel sulfamate system, and the diamond D50 particle size is 7.2μm.

[0160] Preparation of alloy tungsten wire busbar:

[0161] (1) The raw tungsten powder was reduced with hydrogen once, and then doped with rhenium nitrate and lanthanum nitrate, and stirred and mixed to make the doping amount Re be 20 wt% and La be 2.5 wt%.

[0162] (2) The tungsten powder doped in step (1) is reduced in a 700° C. hydrogen reduction furnace, and then reduced again in a 850° C. hydrogen reduction furnace, and then pickled and mixed to obtain mixed alloy tungsten powder.

[0163] (3) isostatically pressing the mixed powder obtained in step (2) to obtain a semi-finished product with a certain density and strength.

[0164] (4) The semi-finished product of step (3) is pre-sintered at a sintering temperature of 1200°C, and then subjected to vertical melting sintering at a sintering temperature of 2900°C.

[0165] (5) The sample prepared in step (4) was subjected to rotary forging and then annealed in a hydrogen-protected heating furnace at a temperature of 1100°C.

[0166] (6) The sample from step (5) is continuously swaged to obtain the desired diameter for wire drawing. The wire drawing die is a diamond die, and the wire drawing lubricant is graphite emulsion. Black wire with graphite emulsion attached to the surface is obtained, and the diameter of the black wire is 44 μm.

[0167] (7) The 44 μm black wire sample in step (6) was electrolyzed, wherein the electrolyte was NAOH with a concentration of 100 g / L, to obtain a 43 μm white tungsten alloy wire with a diameter of 43 ± 0.5 μm, a breaking tensile force ≥ 7.5 N, and an elastic modulus of 368 GPa.

[0168] Preparation of diamond wire:

[0169] (1) The alloy tungsten wire busbar is laid out and pre-treated for surface cleaning. The pre-treatment includes a NAOH alkali solution station with a concentration of 60g / L and a treatment time of 6s; the pre-treatment includes a sulfamic acid solution station with a concentration of 50g / L and a treatment time of 3.5s.

[0170] (2) Impact plating, wherein the impact plating is nickel sulfamate electroplating, wherein Ni is 90 g / L, boric acid is 35 g / L, nickel chloride is 8 g / L, current density is 7 ASD, and the impact plating layer thickness is 100 nm.

[0171] (3) Plating the plating solution using nickel sulfamate electroplating, with a nickel content of 100 g / L, a boric acid content of 30 g / L, and a nickel chloride content of 6 g / L at a current density of 9 ASD. The diamond D50 particle size in the plating solution was 7.2 μm, and the diamond concentration was 2.0 g / L.

[0172] (4) Consolidation, wherein the consolidation is nickel sulfamate electroplating, with Ni being 110 g / L, boric acid being 35 g / L, nickel chloride being 8 g / L, and a current density being 9.5 ASD.

[0173] (5) Post-processing, including a normal temperature pure water washing station and a drying station, with a drying temperature of 180°C. After winding and reeling, a 43 μm alloy tungsten diamond wire saw is obtained, with uniform sanding, a breaking force of ≥8.3N, 0 brittle fracture times, and a knotted breaking force accounting for ≥41% of the total breaking force.

[0174] Tungsten alloy diamond wire cutting applications: Cutting 210 silicon ingots, using the following cutting process: cutting tension of 5.6N, cutting tension ratio ≥ 60%, cutting guide wheel groove depth of 240μm, guide wheel R angle of 30°, cutting fluid pH = 5.0, and cutting fluid supply volume of 1.7L. Single-cut wire consumption was reduced by 12.5%, wire breakage rate was reduced to <1.5%, and average wafer TTV was ≤ 13μm.

[0175] Example 8

[0176] An ultrafine high-strength alloy tungsten wire diamond wire saw consists of an alloy tungsten wire busbar and a surface nickel layer of metal-consolidated diamond. The busbar is a tungsten wire alloy doped with Re and La elements, the nickel plating is a nickel sulfamate system, and the diamond D50 particle size is 7.2μm.

[0177] Preparation of alloy tungsten wire busbar:

[0178] (1) The raw tungsten powder was reduced with hydrogen once, and then doped with rhenium nitrate and lanthanum nitrate, and stirred and mixed to make the doping amount Re be 8.3 wt% and La be 10 wt%.

[0179] (2) The tungsten powder doped in step (1) is reduced in a 700° C. hydrogen reduction furnace, and then reduced again in a 850° C. hydrogen reduction furnace, and then pickled and mixed to obtain mixed alloy tungsten powder.

[0180] (3) isostatically pressing the mixed powder obtained in step (2) to obtain a semi-finished product with a certain density and strength.

[0181] (4) The semi-finished product of step (3) is pre-sintered at a sintering temperature of 1200°C, and then subjected to vertical melting sintering at a sintering temperature of 2900°C.

[0182] (5) The sample prepared in step (4) was subjected to rotary forging and then annealed in a hydrogen-protected heating furnace at a temperature of 1100°C.

[0183] (6) The sample from step (5) is continuously swaged to obtain the desired diameter for wire drawing. The wire drawing die is a diamond die, and the wire drawing lubricant is graphite emulsion. Black wire with graphite emulsion attached to the surface is obtained, and the diameter of the black wire is 44 μm.

[0184] (7) The 44 μm black wire sample in step (6) was electrolyzed, wherein the electrolyte was NAOH with a concentration of 100 g / L, to obtain a 43 μm white tungsten alloy wire with a diameter of 43 ± 0.5 μm, a breaking tensile force ≥ 7.8 N, and an elastic modulus of 390 GPa.

[0185] Preparation of diamond wire:

[0186] (1) The alloy tungsten wire busbar is laid out and pre-treated for surface cleaning. The pre-treatment includes a NAOH alkali solution station with a concentration of 60g / L and a treatment time of 6s; the pre-treatment includes a sulfamic acid solution station with a concentration of 50g / L and a treatment time of 3.5s.

[0187] (2) Impact plating, wherein the impact plating is nickel sulfamate electroplating, wherein Ni is 90 g / L, boric acid is 35 g / L, nickel chloride is 8 g / L, current density is 7 ASD, and the impact plating layer thickness is 100 nm.

[0188] (3) Plating the plating solution using nickel sulfamate electroplating, with a nickel content of 100 g / L, a boric acid content of 30 g / L, and a nickel chloride content of 6 g / L at a current density of 9 ASD. The diamond D50 particle size in the plating solution was 7.2 μm, and the diamond concentration was 2.0 g / L.

[0189] (4) Consolidation, wherein the consolidation is nickel sulfamate electroplating, with Ni being 110 g / L, boric acid being 35 g / L, nickel chloride being 8 g / L, and a current density being 9.5 ASD.

[0190] (5) Post-processing, including a normal temperature pure water washing station and a drying station, with a drying temperature of 180°C. After winding and reeling, a 43 μm alloy tungsten diamond wire saw is obtained, with uniform sanding, a breaking force of ≥8.6N, 0 brittle fracture times, and a knotted breaking force accounting for ≥45% of the total breaking force.

[0191] Tungsten alloy diamond wire cutting applications: Cutting 210 silicon ingots, using the following cutting process: cutting tension of 5.6N, cutting tension ratio ≥ 60%, cutting guide wheel groove depth of 240μm, guide wheel R angle of 30°, cutting fluid pH = 5.0, and cutting fluid supply volume of 1.7L. Single-cut wire consumption was reduced by 13%, wire breakage rate was reduced to <1.0%, and average wafer TTV was ≤ 10μm.

[0192] The parameters of the tungsten alloy diamond wire saw and the customer cutting verification data in the above comparative example and the eight embodiments are shown in Table 1 and Table 2 respectively.

[0193] Table 1 Performance parameters of diamond wires obtained in Examples 1 to 8

[0194]

[0195]

[0196] Table 2 Customer application performance of the products in Examples 1 to 8.

[0197]

[0198]

[0199] From the data in Table 1 and Table 2, we can see that:

[0200] The present invention can produce an alloy tungsten wire busbar with higher strength than carbon steel busbars of the same specifications, lower brittle fracture frequency, higher elastic modulus, and stronger corrosion resistance by doping the alloy busbar raw material with metal elements: Re and La according to a certain doping content. This significantly reduces the wire breakage rate during cutting. In the diamond wire manufacturing process, the alloy tungsten wire busbar significantly helps the sanding capacity and sanding uniformity by increasing the thickness of the impact-plated coating. The production line speed is significantly improved compared to ordinary carbon steel busbars. The resulting alloy tungsten wire diamond wire saw can maintain its busbar performance and possess mechanical properties such as lower brittle fracture frequency and higher breaking force. In photovoltaic silicon wafer cutting applications, through the optimization of specific cutting techniques (including: guide wheel groove depth, R angle change, reduction of cutting fluid pH, and increase in cutting tension load ratio), a significant improvement in cutting efficiency is achieved, and the single-wafer line consumption and silicon wafer TTV average are significantly reduced.

[0201] The above description is only a specific embodiment of the present invention. It should be noted that, for the field of diamond wire saw manufacturing, the present invention extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A tungsten alloy wire, characterized in that The tungsten wire is doped with 8.3-20% Re and 2.5-13.32% La by mass. The diameter of the tungsten alloy wire is 30-50 μm, the strength is ≥5100 MPa, and the elastic modulus is 350-450 GPa.

2. A method for preparing the tungsten alloy wire according to claim 1, comprising the following steps: Step 1: The raw tungsten powder is reduced with hydrogen, then pickled and impurities removed to obtain tungsten powder with a purity of ≥99%; Step 2: Spray rhenium nitrate and lanthanum nitrate solutions onto the tungsten powder obtained in step 1 and stir to mix, so that the doping amount of Re is 8.3-20 wt% and La is 2.5-13.32 wt%; Step 3: The mixed tungsten powder obtained in step 2 is subjected to a primary hydrogen reduction in a 700°C hydrogen reduction furnace and a secondary hydrogen reduction in a 850°C hydrogen reduction furnace to obtain a mixed alloy tungsten powder; Step 4: isostatically press the mixed alloy tungsten powder obtained in step 3 to obtain a tungsten powder having a density of 8.0 to 15 g / cm 3 , semi-finished products with forming strength; Step 5: pre-sinter the semi-finished product obtained in step 4 at a sintering temperature of 1200° C. for 45 to 65 minutes, and then perform vertical melting sintering at a sintering temperature of 2900° C. for 110 to 130 minutes; Step 6: The product obtained in step 5 is subjected to rotary forging to form a blank, and then annealed in a hydrogen protection heating furnace at an annealing temperature of 1100° C. Step 7: The product obtained in step 6 is continuously swaged to prepare an alloy tungsten rod with a diameter of 2 to 3 mm, the surface of which is evenly coated with graphite emulsion, and then drawn through a diamond die to a tungsten alloy wire with a diameter of 30 to 50 μm.

3. The method according to claim 2, characterized in that The pickling and impurity removal in step 1 adopts a mixed solution of aminosulfonic acid and hydrochloric acid, wherein the concentration of aminosulfonic acid is 50g / L and the concentration of hydrochloric acid is 60ml / L.

4. The method according to claim 2, characterized in that The process parameters of the isostatic pressing in step 3 are 150-230 MPa, and the pressing is maintained for 30-60 minutes.

5. The method according to claim 2, characterized in that In the step 7, the diamond mold is a 7.5° diamond mold, and the graphite emulsion is graphite nano powder with D50=0.2 μm.

6. A diamond wire saw made from the tungsten alloy wire according to claim 1, characterized in that It includes a tungsten wire alloy busbar, a pre-plated nickel layer, a top sand nickel layer and a solid sand nickel layer from the inside out, wherein the thickness of the pre-plated nickel layer is 30 to 500 nm, the diameter of the diamond wire saw is 45 to 65 μm, and the breaking tensile force is 6.5 to 11 N.

7. A method for preparing the diamond wire saw according to claim 6, comprising the following steps: Step 1: After the tungsten alloy wire is paid out, it is first treated with a 60g / L NaOH solution for 6 seconds; then treated with a 50g / L sulfamic acid solution for 3.5 seconds; Step 2: impact plating, the impact plating is nickel sulfamate electroplating, Ni is 90g / L, boric acid is 35g / L, nickel chloride is 8g / L, the current density is 7ASD, and the impact plating layer thickness is 100nm; Step 3: sanding, the sanding is nickel sulfamate electroplating, Ni is 100g / L, boric acid is 30g / L, nickel chloride is 6g / L, the current density is 9ASD, the diamond D50 particle size in the sanding plating solution is 7.2μm, and the diamond concentration is 2.0g / L; Step 4: consolidation, the consolidation is nickel sulfamate electroplating, Ni is 110g / L, boric acid is 35g / L, nickel chloride is 8g / L, and the current density is 9.5ASD; Step 5: Post-processing, which includes washing with pure water at room temperature, drying at 180°C, and winding to obtain a diamond wire saw with a wire diameter of 45 to 65 μm.

8. A method for using a diamond wire saw according to claim 6, characterized in that A tungsten alloy diamond wire saw is rewound onto a slotting guide wheel under a tension of 3.5 to 6.0 N to form a densely wired mesh running at a speed of 600 to 2100 m / min. The silicon rod to be cut is pressed into the densely wired mesh at a table speed of 200 to 2100 mm / min under cooling with a cutting fluid. The silicon rod is cut into silicon wafers of uniform thickness using the cutting force of the tungsten alloy diamond wire saw. The wire mesh length is 4.5 to 8.0 km, the slotting guide wheel diameter is 190 to 210 mm, the slotting angle is 20 to 40°, the guide wheel slot depth is 150 to 240 μm, and the guide wheel slot R angle is 20 to 45°. The cutting fluid is a cutting water solution with a high organic matter COD content, the pH of which is controlled at 3.5 to 6.

5. The cutting process table speed is 200 to 2100 mm / min, and the wire speed is 600 to 2100 m / min.

9. The method for using a diamond wire saw according to claim 8, characterized in that The slotted guide wheel has two axes or three axes.

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