Diamond fretsaw with carbon nanotube composite coating and preparation method

Abstract

The invention discloses a diamond fretsaw with a carbon nanotube composite coating and a preparation method. The diamond fretsaw comprises a base material and the composite coating deposited on the outer surface of the base material. Carbon nanotubes are uniformly distributed in the composite coating, and diamond abrasive particles are embedded in the surface of the composite coating. The problems that diamond abrasive particles of an existing fret saw are prone to falling off, a plating layer is prone to abrasion and the service life is short are solved, the composite plating layer is formed by adding the carbon nanotubes into the electroplating liquid, the mechanical performance of the composite plating layer can be remarkably improved, and the fret saw can still keep good cutting performance under high load; and meanwhile, the wear resistance, the strength, the thermal conductivity and the binding force of the composite coating are improved. In addition, the diamond abrasive particles are embedded in the composite plating layer, the binding force between the diamond abrasive particles and the base material can be enhanced through the carbon nano tubes in the composite plating layer, falling of the particles is reduced, and the service life of the wire saw is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of wire saw production, and in particular to a diamond wire saw with a carbon nanotube composite coating and a preparation method thereof. Background Art

[0002] Electroplated diamond wire saw is an important tool widely used in the cutting of hard and brittle materials (such as sapphire, silicon wafers, quartz glass, etc.). Its core technology is to evenly attach diamond abrasive particles to the surface of the base wire saw through the electroplating process, so as to cut the material by utilizing the high hardness and sharpness of diamond. However, with the increasing requirements for cutting accuracy, efficiency and cost control, the shortcomings of existing electroplated diamond wire saws are gradually emerging.

[0003] Diamond is widely used in the processing of high-hardness materials such as cutting and grinding due to its superhardness. In the process of cutting hard and brittle materials (such as sapphire), electroplated diamond wire saws have the characteristics of high cutting accuracy, high efficiency and low loss, so they are widely used in the field of precision machining. The electroplating process coats a layer of metal (usually nickel or nickel alloy) on the surface of the base wire saw, firmly embedding the diamond abrasive particles into it, making the surface of the wire saw extremely hard and wear-resistant, thereby achieving efficient cutting of high-hardness materials.

[0004] Existing electroplated diamond wire saws have the following major problems: (1) Diamond abrasives are easy to fall off. The diamond particles in the electroplating layer are attached to the substrate through the metal nickel layer. However, due to the limited strength of the electroplating layer, the electroplating layer is prone to wear or cracking during high-speed cutting, resulting in the falling off of diamond particles. The falling off of diamond particles not only leads to a decrease in the cutting performance of the wire saw, but also greatly shortens the service life of the wire saw. (2) The electroplating layer has insufficient wear resistance. The wear resistance of the electroplating layer plays a decisive role in the cutting performance and life of the wire saw. However, the traditional nickel-based electroplating layer is susceptible to external forces such as friction and impact during the cutting process, and has limited wear resistance, making it difficult to maintain stable performance under long-term high-load conditions. Therefore, the electroplating layer wears quickly, resulting in the wire saw needing to be replaced or maintained more frequently. (3) Low cutting efficiency and high cost. Due to the shedding of diamond abrasives and the wear of the electroplating layer, the cutting efficiency of the wire saw gradually decreases, and the vibration and heat generated during the cutting process will also affect the cutting effect. At the same time, frequent replacement of the wire saw not only increases downtime, but also increases production costs. (4) Unstable performance under high temperature and high pressure. When cutting hard and brittle materials such as sapphire at high temperature and high speed, the bonding strength between the electroplating layer and the diamond particles is insufficient, causing the wire saw to be easily deformed, broken or damaged. In addition, the thermal stability of the electroplating layer is not enough. As the temperature rises, the adhesion of the diamond particles will decrease, further accelerating the failure of the wire saw. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the existing wire saw diamond abrasive grains are easy to fall off, the coating is easy to wear and the service life is short; the purpose is to provide a diamond wire saw with a carbon nanotube composite coating and a preparation method, which solves the problems of the existing wire saw diamond abrasive grains being easy to fall off, the coating being easy to wear and the service life being short.

[0006] The present invention is achieved through the following technical solutions:

[0007] A diamond wire saw with a carbon nanotube composite coating comprises a base material and a composite coating deposited on the outer surface of the base material; carbon nanotubes are evenly distributed inside the composite coating, and diamond abrasive grains are embedded on the surface of the composite coating.

[0008] As one of the preferred technical solutions, the diameter of the base material is 0.18-0.23 mm.

[0009] As one of the preferred technical solutions, the diamond abrasive grains include coarse diamond abrasive grains and fine diamond abrasive grains, the particle size of the coarse diamond abrasive grains is 90-100 μm, the particle size of the fine diamond abrasive grains is 40-60 μm, and the content ratio of the coarse diamond abrasive grains to the fine diamond abrasive grains is 1:5-6.

[0010] The beneficial effect is that the diamond abrasives currently used in the electroplated diamond wire saw for sapphire are mostly fine-grained diamond abrasives. The present invention adds a certain proportion of coarse-grained diamond abrasives. The added coarse-grained diamond abrasives have a larger cutting edge, can remove materials faster, and improve cutting efficiency; according to the principle that under the same pressure, the larger the contact area, the greater the pressure that can be tolerated, the coarse-grained diamond abrasives can withstand greater cutting pressure, make the stress distribution more uniform, enhance wear resistance, and provide stronger cutting strength for the cutting process (the enhancement of cutting strength can be measured by comparing the wire diameter wear rate of the present invention with that of ordinary wire saws).

[0011] Another aspect of the present invention provides a method for preparing a diamond wire saw having a carbon nanotube composite coating, comprising the following steps:

[0012] Pre-treatment of the matrix material and diamond abrasive grains, including degreasing, acidification and activation;

[0013] Prepare basic electroplating solution;

[0014] Activation and dispersion of carbon nanotubes, finally the carbon nanotubes are evenly dispersed in the electroplating solution to form a composite electroplating solution;

[0015] The base material is pre-plated, the pre-treated base material is placed in an electroplating tank, and the composite electroplating solution is deposited on the base material to form a composite coating;

[0016] Sanding, electroplating diamond abrasives onto the composite coating, controlling the current density and electroplating time to make the diamond abrasives evenly distributed on the composite coating;

[0017] Thicken, control the current density and electroplating time and embed 2 / 3 volume of diamond particle size in the composite coating;

[0018] Post-processing: the electroplated diamond wire saw is cleaned, dried, and heat-treated to improve the hardness and bonding strength of the composite coating.

[0019] As one of the preferred technical solutions, the addition amount of carbon nanotubes is 0.1-0.4 g / L.

[0020] As one of the preferred technical solutions, the current density during the pre-plating process is in the range of 0.5-1.5A / dm 2 The electroplating time is 5-15min; the current density during the sand electroplating process ranges from 1.5-2.5A / dm 2 The electroplating time is 15-25min, and the current density during the thickening process is in the range of 1.5-2.0A / dm 2 The electroplating time is 60-90min.

[0021] As one of the preferred technical solutions, the carbon nanotubes are pre-treated to be positively charged, and the electrophoresis effect is used when the carbon nanotubes are deposited.

[0022] As one of the preferred technical solutions, the positively charged pretreatment method includes cationic surfactant modification.

[0023] As one of the preferred technical solutions, after the electroplating is completed, the electroplated wire saw is heat treated at a temperature of 230-260° C. for 30-60 minutes.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] 1. The present invention forms a composite coating by adding carbon nanotubes to the electroplating solution, which can significantly improve the mechanical properties of the composite coating, so that the wire saw can still maintain good cutting performance under high load; at the same time, the wear resistance, strength, thermal conductivity and bonding strength of the coating are improved. In addition, diamond particles are embedded in the composite coating, and the carbon nanotubes in the composite coating can enhance the bonding strength between the diamond particles and the substrate, reduce the shedding of particles, and extend the service life of the wire saw. Due to the enhanced performance of the composite coating, the vibration and heat generated during the cutting process can be effectively controlled, reducing damage to brittle materials such as sapphire.

[0026] 2. The electroplated diamond wire saw in the present invention has better wear resistance, higher hardness, self-sharpening and longer service life. The invention is suitable for large-scale production, has strong adaptability, and is suitable for various wire saw preparation needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0028] Figure 1 A schematic diagram of the microstructure of an electroplated diamond wire saw having a carbon nanotube composite coating in the present invention;

[0029] Figure 2 This is a schematic diagram of the wear of an ordinary wire saw;

[0030] Figure 3 It is a schematic diagram of the wear condition of the wire saw of the present invention;

[0031] Figure 4 This is a schematic diagram of the surface of a substrate for electrophoresis-assisted carbon nanotube deposition in the present invention. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0033] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0034] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0035] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0036] Example 1

[0037] This embodiment provides a method for preparing a diamond wire saw having a carbon nanotube composite coating, which is used to prepare the diamond wire saw, comprising the following steps:

[0038] The diamond abrasive (including coarse diamond abrasive and fine diamond abrasive) and the matrix material are pre-treated by degreasing, pickling and activation. The coarse diamond abrasive has a particle size of 90-100μm, the fine diamond abrasive has a particle size of 40-60μm, and the content ratio is 1:5. The matrix material is made of piano wire with a diameter of 0.2mm, so as to ensure that the matrix material has good mechanical strength and toughness, so as to ensure that it can withstand large tensile force and mechanical load during the cutting process.

[0039] The surface treatment of the substrate material mainly includes cleaning and roughening. Cleaning is to use organic solvents (such as ethanol, acetone, etc.) to remove impurities such as oil, dust, etc. on the substrate surface to ensure the surface is clean. Then, an acid solution (such as dilute hydrochloric acid or sulfuric acid) is used to pickle the substrate to further remove surface oxides, rust spots, etc., exposing the active metal surface.

[0040] Roughening is to roughen the substrate surface by physical or chemical methods to increase its surface roughness. Common methods include sandblasting, mechanical grinding or chemical etching to improve the adhesion of the composite coating. After the substrate treatment is completed, the surface moisture must be removed by hot air or natural drying to avoid bubbles or poor coating adhesion during the electroplating process.

[0041] Preparation of basic electroplating solution: Add the following ingredients to the electroplating tank to prepare the electroplating solution: nickel sulfate (NiSO4·6H2O), 250g / L; nickel chloride (NiCl2·6H2O), 50g / L; boric acid (H3BO3), 25g / L; surfactant, 0.5g / L; the pH value of the electroplating solution is adjusted to 4.0, and the temperature is controlled at 50°C. The composition and configuration of the electroplating solution directly affect the quality of the coating and the embedding effect of the diamond abrasive. In the nickel plating process, due to the dissociation of boric acid, it is beneficial to inhibit the hydrolysis reaction of nickel sulfate, so that the electrodeposition reaction can proceed smoothly.

[0042] Activation of carbon nanotubes: Multi-walled carbon nanotubes (MWCNTs) with a diameter of 10-20 nm and a length of 1-5 μm are selected, the agglomerated part of the carbon nanotube raw material is ground and crushed to disperse, and then ultrasonically dispersed for 40-50 minutes with an ultrasonic power of 200-300W.

[0043] Since nanomaterials usually have strong agglomeration, it is difficult to evenly distribute them in the electroplating solution. To further ensure the uniform dispersion of carbon nanotubes, this embodiment uses ultrasonic dispersion technology, which can effectively break the agglomeration of nanomaterials and evenly disperse them in the electroplating solution. The ultrasonic power is 300-500W and the duration is 30-60min.

[0044] Weigh 0.1-0.4g of carbon nanotubes and add them to the flask. Slowly add 20-30mL of pre-prepared mixed acid solution of concentrated nitric acid and concentrated sulfuric acid (ratio 1:3-4) to the flask. This process should be carried out in an ice-water bath, and the acid solution should be added slowly while stirring continuously. Because the mixed acid solution reacts violently and releases a lot of heat, ice-water bath and slow operation can avoid danger and prevent the carbon nanotubes from being damaged due to overheating. Transfer the flask to an oil bath pot and heat it under reflux at a certain temperature (such as 80-90℃) for 2-4 hours (during this process, the mixed acid solution will oxidize the surface of the carbon nanotubes, so that it is connected to oxygen-containing functional groups such as carboxyl (-COOH). The reaction formula is: some carbon bonds are broken under the action of strong oxidants, and then combined with oxygen in the acid solution to form functional groups such as carboxyl connected to the surface of the carbon nanotubes). After the reaction is completed, the reaction system is cooled to room temperature and slowly poured into a large amount of deionized water for dilution, followed by multiple centrifugation (8000-10000 rpm for 10-20 minutes) and water washing operations until the pH value of the supernatant is close to neutral, thereby washing away excess acid to obtain carbon nanotubes with carboxyl functional groups grafted on the surface.

[0045] Positively charged pretreatment:

[0046] In this embodiment, a cationic surfactant is used to pre-treat carbon nanotubes with positive charge. In this embodiment, hexadecyl trimethyl ammonium bromide (CTAB) is selected as a cationic surfactant. The content ratio of CTAB to carbon nanotubes with carboxyl functional groups grafted on the surface is between 1-3:1. The carbon nanotubes with carboxyl functional groups grafted on the surface are transferred to a clean container, deionized water is added, and the concentration of the carbon nanotubes is 1-5 mg / mL, and then ultrasonic dispersion is performed, the ultrasonic power is 200-400 W, and the ultrasonic time is 30-60 minutes to uniformly disperse the carbon nanotubes. The weighed CTAB is slowly added to the dispersed carbon nanotube solution, and the reaction is stirred at room temperature for 2-4 hours. Because the cationic part of CTAB will electrostatically adsorb with the carboxyl group on the surface of the carbon nanotube, the carbon nanotube is positively charged. The stirring speed can be controlled at 300-500rpm to ensure sufficient mixing reaction.

[0047] Dissolve the carbon nanotube mixed solution in the electroplating solution:

[0048] Mixing process: After the carbon nanotubes have been treated with cationic surfactants to be positively charged, the above carbon nanotube mixed solution is slowly added to the electroplating solution. Stirring should be performed during the addition process, and the stirring speed can be around 400-600rpm to help the carbon nanotubes disperse evenly in the electroplating solution. In order to further improve the dispersibility of the carbon nanotubes in the electroplating solution, the electroplating solution can be ultrasonically treated after addition, with an ultrasonic power of 300-500W and an ultrasonic time of 30-60 minutes.

[0049] Since carbon nanotubes carry positive charges, the use of electric fields during pre-plating and thickening can effectively assist the directional deposition of carbon nanotubes onto the substrate material. Figure 4 As shown, after the electrophoresis effect occurs, the surface of the base material is evenly distributed, the color and thickness are relatively consistent, and there are fewer uneven phenomena such as local accumulation or sparseness. The dispersion of carbon nanotubes is a key step to ensure that they are evenly distributed in the electroplating solution, so as to ensure that they can be deposited on the surface of the base material together with the basic electroplating solution during the subsequent electroplating process.

[0050] By adding carbon nanotube material into the electroplating solution and distributing it in the composite coating, the strength and wear resistance of the composite coating and the adhesion of diamond particles are enhanced.

[0051] Pre-plating, the current density during the pre-plating process ranges from 0.5-1.5A / dm 2 The electroplating time is 5-15 minutes. Preferably, the current density during the pre-plating process of this embodiment is 1.5A / dm 2 , the plating time is 10 minutes.

[0052] It is important to note that a higher current density may lead to uneven dispersion of carbon nanotubes in the electroplating solution, resulting in poor embedding in the composite coating, while a current density that is too low will reduce the electrodeposition rate. Too long an electroplating time will lead to carbon nanotube aggregation, while too short an electroplating time will result in insufficient deposition of the nanomaterial.

[0053] The temperature of the electroplating solution also has an important influence on the deposition efficiency and uniformity of nanomaterials. The electroplating temperature is controlled between 40-60°C, which can not only increase the deposition rate of nickel ions, but also prevent excessive agglomeration of carbon nanotubes.

[0054] The pretreated substrate material is placed in the electroplating tank, and the composite electroplating solution is deposited on the substrate material to form a composite coating; during the electroplating process, the electroplating solution is continuously stirred to ensure that the nanomaterial does not settle, and the stirring speed should be controlled to keep the particles suspended without causing excessive bubbles in the electroplating solution. Preferably, the stirring speed is 200-300RPM, and the duration is the entire electroplating process to ensure that the nanomaterial does not settle.

[0055] Sanding, electroplating diamond abrasives onto the composite coating, controlling the current density and electroplating time to make the diamond abrasives evenly distributed on the composite coating; refer to the existing buried sand process for sanding electroplating, the current density range of the sanding electroplating process is 1.5-2.5A / dm 2 The electroplating time is 15-25 min. Preferably, the current density is 2 A / dm 2 , the plating time is 20 minutes.

[0056] Thickening, thickening the composite coating, controlling the current density and electroplating time and embedding 2 / 3 of the volume of the diamond particle size in the composite coating; further, the current density during the thickening process is in the range of 1.5-2.0A / dm 2 The electroplating time is 60-90 minutes. Preferably, the current density during the thickening process is 1.5A / dm 2 , the plating time is 80 minutes.

[0057] After the electroplating is completed, the electroplating liquid remaining on the surface of the electroplated wire saw is thoroughly cleaned with deionized water. Preferably, it is dried at 70°C for 15 minutes and then heat treated in an oven at 250°C for 45 minutes to enhance the strength and bonding of the composite coating. After the electroplating is completed, the electroplated wire saw is heat treated at a temperature of 230-260°C for 30-60 minutes.

[0058] Finally, a diamond wire saw 1 is prepared through Example 1, and its specific structure is as follows: Figure 1As shown. Carbon nanotubes are evenly distributed inside the composite coating, and diamond abrasive particles are embedded on its surface. The base material can be spring steel wire, piano wire or other high-strength materials, so as to ensure that the base material has good mechanical strength and toughness, so as to ensure that it can withstand large tensile force and mechanical load during the cutting process.

[0059] The diameter of the base material is 0.18-0.23 mm. Preferably, the base material in this embodiment is a piano wire with a diameter of 0.2 mm. It can be known that the composite coating provides support during the cutting process and protects the base material from wear, and the diamond abrasive grains play a cutting role during the cutting process.

[0060] Example 2

[0061] The steps of this embodiment are basically the same as those of embodiment 1, except that the content ratio of the coarse-grained diamond abrasive grains to the fine-grained diamond abrasive grains is 1:6. A diamond wire saw 2 is prepared through embodiment 2.

[0062] Example 3

[0063] The steps of this embodiment are basically the same as those of embodiment 1, except that the ratio of the coarse-grained diamond abrasive grains to the fine-grained diamond abrasive grains is 1:5.5. A diamond wire saw 3 is prepared through embodiment 3.

[0064] Comparative Example 1

[0065] The steps of this comparative example 1 are basically the same as those of the embodiment 1, except that only fine-grained diamond abrasive grains are added. A diamond wire saw 4 is prepared through comparative example 1.

[0066] Comparative Example 2

[0067] The steps of Comparative Example 1 are basically the same as those of Example 1, except that only coarse diamond abrasive grains are added. A diamond wire saw 5 is prepared through Comparative Example 1.

[0068] Effect comparison:

[0069] (1) The wire diameter of the wire saw prepared in Example 1, Example 2, and Example 3 is 0.24±0.05mm, the wire diameter of the wire saw prepared in Comparative Example 1 is 0.24±0.01mm, and the wire diameter of the wire saw prepared in Comparative Example 2 is 0.28±0.01mm, and the input wire consumption is 1350m; the wire diameter of the ordinary wire saw (without carbon nanotube composite coating) is 0.22±0.01mm, and the input wire consumption is 2250m. A 6-inch sapphire crystal rod with a length of 40cm from the same manufacturer was cut, and 25 pieces were cut. The cutting amount was set to 158mm, the cutting time was set to 11h32min, the wire speed was set to 2200m / min, the wire tension was set to 47N, the cutting fluid flow was set to 45-50L / min, and the set temperature was 21-22 degrees Celsius; the specific results are shown in Table 1.

[0070] Table 1 Comparison of cutting results of 6-inch sapphire crystal rod

[0071]

[0072] Conclusion: By comparing diamond wire saw 1-3 and ordinary wire saw, it can be seen that after diamond wire saw 1-3 cuts sapphire crystal rod under the same conditions, the quality index of sapphire wafer is significantly improved. According to the change of wire diameter before and after cutting, the wear rate of diamond wire saw prepared in Example 1-3 is significantly lower than that of ordinary wire saw. Under the condition of ensuring the average quality index, the single-piece wire consumption of Example 1-3 is lower, the single-piece wire consumption of ordinary wire saw is about 70-80m / piece, and the single-piece consumption of diamond wire saw 1-3 is about 40-50m / piece, and the wire saw wear is lower. Ordinary wire saw can cut 6-inch sapphire crystal rod twice, and the diamond wire saw prepared in Example 1 can cut 6-inch sapphire crystal rod three times. Figure 2 This is the wear condition of ordinary wire saw. Figure 3 The wear condition of the diamond wire saw 1 of the present invention is shown. It can be seen that the abrasive grain shedding phenomenon of the ordinary wire saw is serious, while the abrasive grain shedding phenomenon of the diamond wire saw 1 is relatively low and has good self-sharpening property, which is due to the strong bonding force and high strength of the carbon nanotube reinforced composite coating.

[0073] Comparing diamond wire saws 1-5, the wire diameter wear rate after cutting reflects the cutting strength, and the average Ra is used to reflect the cutting accuracy. The cutting strength and cutting accuracy of diamond wire saws 1-3 are good and the quality indicators of wafers are the best. The cutting strength of diamond wire saw 4 is average, and the cutting accuracy of diamond wire saw 5 is poor. It can be seen that the combination of coarse-grained diamond abrasives and fine-grained diamond abrasives can better increase the performance of the wire saw.

[0074] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A diamond wire saw with a carbon nanotube composite coating, characterized in that: It comprises a base material and a composite coating deposited on the outer surface of the base material; carbon nanotubes are evenly distributed inside the composite coating, and diamond abrasive grains are embedded on the surface of the composite coating.

2. The diamond wire saw with carbon nanotube composite coating according to claim 1, characterized in that: The diameter of the base material is 0.18-0.23 mm.

3. The diamond wire saw with carbon nanotube composite coating according to claim 1, characterized in that: The diamond abrasive grains include coarse diamond abrasive grains and fine diamond abrasive grains, the particle size of the coarse diamond abrasive grains is 90-100 μm, the particle size of the fine diamond abrasive grains is 40-60 μm, and the content ratio of the coarse diamond abrasive grains to the fine diamond abrasive grains is 1:5-6.

4. A method for preparing a diamond wire saw having a carbon nanotube composite coating, characterized in that: The steps include: Pre-treatment of the matrix material and diamond abrasive grains, including degreasing, acidification and activation; Prepare basic electroplating solution; Activation and dispersion of carbon nanotubes, finally the carbon nanotubes are evenly dispersed in the electroplating solution to form a composite electroplating solution; The base material is pre-plated, the pre-treated base material is placed in an electroplating tank, and the composite electroplating solution is deposited on the base material to form a composite coating; Sanding, electroplating diamond abrasive grains onto the composite coating, controlling the current density and electroplating time to make the diamond abrasive grains evenly distributed on the composite coating; Thicken, control the current density and electroplating time and embed 2 / 3 volume of diamond abrasive grains in the composite coating; Post-processing: the electroplated diamond wire saw is cleaned, dried, and heat-treated to improve the hardness and bonding strength of the composite coating.

5. The method for preparing a diamond wire saw having a carbon nanotube composite coating according to claim 4, characterized in that: The added amount of carbon nanotubes is 0.1-0.4 g / L.

6. The method for preparing a diamond wire saw having a carbon nanotube composite coating according to claim 4, characterized in that: The current density during the pre-plating process ranges from 0.5-1.5A / dm 2 The electroplating time is 5-15min; the current density during the sand electroplating process ranges from 1.5-2.5A / dm 2 The electroplating time is 15-25min, and the current density during the thickening process is in the range of 1.5-2.0A / dm 2 The electroplating time is 60-90min.

7. The method for preparing a diamond wire saw having a carbon nanotube composite coating according to claim 4, characterized in that: The carbon nanotubes are pre-treated with positive charge, and the electrophoresis effect is used during the deposition of the carbon nanotubes.

8. The method for preparing a diamond wire saw having a carbon nanotube composite coating according to claim 4, characterized in that: Positively charged pretreatment methods include cationic surfactant modification.

9. The method for preparing a diamond wire saw having a carbon nanotube composite coating according to claim 4, characterized in that: After the electroplating is completed, the electroplated wire saw is heat treated at a temperature of 230-260°C for 30-60 minutes.

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