Composite diamond material, preparation method thereof and diamond modified fret saw

Abstract

The invention provides a composite diamond material, a preparation method thereof and a diamond modified fret saw, and belongs to the technical field of materials. The preparation method comprises the following steps: preparing melamine-formaldehyde resin microspheres, loading tungsten oxide on the surfaces of the melamine-formaldehyde resin microspheres and complexing nickel oxide to prepare tungsten oxide / nickel oxide coated melamine-formaldehyde resin microspheres, heating and calcining to prepare tungsten-nickel alloy coated carbon nanotube Janus nanosheets, and mixing and ball-milling the tungsten-nickel alloy coated carbon nanotube Janus nanosheets and activated diamond micro-powder subjected to plasma treatment to prepare the composite diamond material. The prepared composite diamond material can obviously improve the adhesive force with fretsaw steel, so that the hardness, the strength, the wear resistance, the heat conduction and heat resistance, the antistatic performance and the like of a fretsaw are improved, and the application range of the fretsaw is obviously widened.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of materials, in particular to a composite diamond material, a preparation method thereof and a diamond modified wire saw. BACKGROUND

[0002] In the cutting of hard and brittle materials such as silicon crystals, gems and ceramics, the cutting tools mainly include free abrasive wire saws and fixed abrasive wire saws. The preparation methods of the fixed abrasive wire saws include resin binder curing technology and electroplating technology. The resin binder diamond wire saw has poor wear resistance and heat resistance, and low abrasive holding force. The electroplated diamond wire saw cutting technology has the following shortcomings: poor mechanical properties, many defects, leading to the fracture of the electroplated diamond wire saw during cutting; low holding force of the plating layer on the diamond, and the cutting performance gradually decreases due to the wear and shedding of the diamond abrasive particles and other reasons as the number of processing increases; high cost and low preparation efficiency.

[0003] At present, in order to prolong the service life of the diamond wire saw, the mechanical properties of the diamond wire saw and the holding force of the plating layer on the diamond need to be improved. In addition, the wire saw generates a lot of heat during work, and has higher requirements for its heat resistance and heat dissipation. SUMMARY

[0004] The purpose of the present application is to provide a composite diamond material, a preparation method thereof and a diamond modified wire saw, which can significantly improve the adhesion to the wire saw steel material, thereby improving the hardness, strength, wear resistance, heat conduction and heat resistance, anti-static performance and the like of the wire saw, and thereby significantly widening the application range of the wire saw.

[0005] The technical scheme of the present application is as follows: The present application provides a preparation method of a composite diamond material, melamine-formaldehyde resin microspheres are prepared, tungsten oxide and nickel oxide are loaded on the surface and complexed, tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres are prepared, the tungsten-nickel alloy@carbon nanotube Janus nanosheet is prepared by heating and calcining, and the composite diamond material is prepared by mixing the activated diamond micro powder treated by plasma and ball milling.

[0006] As a further improvement of the present application, the following steps are included: S1. Melamine, formaldehyde, water, polyvinyl alcohol and oxalic acid are uniformly mixed, heated and stirred to react, centrifuged, washed, dried, and melamine-formaldehyde resin microspheres are prepared; S2. Sodium tungstate is dissolved in water, melamine-formaldehyde resin microspheres and ammonium chloride are added, concentrated hydrochloric acid is added dropwise, stirred, filtered, centrifuged and dried to obtain tungsten oxide@melamine-formaldehyde resin microspheres; S3. The tungsten oxide / melamine-formaldehyde resin microspheres are added into a solution containing a nickel salt, uniformly dispersed, a complexing agent is added, the solvent is evaporated by heating, a sol is obtained, then the temperature is increased and the vacuum degree is reduced, a xerogel is obtained, ball milling is performed, and tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres are prepared; S4. The tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres are calcined by heating under inert gas protection, ball milling is performed, and tungsten-nickel alloy@carbon nanotube Janus nanosheet is prepared; S5. Diamond micro-powder is soaked in acetone, filtered, dried, and treated by plasma to obtain activated diamond micro-powder; S6. The activated diamond micro-powder and the tungsten-nickel alloy@carbon nanotube Janus nanosheet are uniformly mixed, and ball milling is performed to obtain a composite diamond material.

[0007] As a further improvement of the present application, the mass ratio of the melamine, formaldehyde, water, polyvinyl alcohol and oxalic acid in step S1 is 1.5-2.5:1.5-2.5:95-105:0.4-0.6:0.15-0.25, the temperature of the heating and stirring reaction is 75-85℃, and the time is 5-15 min.

[0008] As a further improvement of the present application, the mass ratio of the sodium tungstate, melamine-formaldehyde resin microspheres, ammonium chloride and concentrated hydrochloric acid in step S2 is 2-4:4-6:0.5-1:1-2.

[0009] As a further improvement of the present application, the mass ratio of the tungsten oxide / melamine-formaldehyde resin microspheres, nickel salt and complexing agent in step S3 is 10:2-4:3-5, the nickel salt is selected from at least one of nickel chloride, nickel sulfate and nickel nitrate, the complexing agent is citric acid or sodium citrate, the heating temperature is 50-70℃, the temperature is increased to 120-150℃, and the vacuum degree is reduced to 0.01-0.1 MPa; the ball milling time is 1-2 h.

[0010] As a further improvement of the present application, the heating and calcination temperature in step S4 is 850-950℃, the time is 60-90 min, and the ball milling time is 3-5 h.

[0011] As a further improvement of the present application, the plasma treatment conditions in step S5 are as follows: the hydrogen flow rate is 40-60 sccm, the oxygen flow rate is 40-60 sccm, the substrate temperature is 350-450℃, the gas pressure is 3-4 kPa, the power is 600-700 W, and the time is 15-25 min.

[0012] As a further improvement of the present application, the mass ratio of the activated diamond powder and the tungsten-nickel alloy / carbon nanotube Janus nanosheet in step S6 is 10:4-7, and the ball milling time is 3-5h.

[0013] The present application further protects a composite diamond material prepared by the above preparation method.

[0014] The present application further protects a diamond modified wire saw, which adds the above composite diamond material to the coating, coats the wire saw, and prepares the diamond modified wire saw after curing.

[0015] The present application has the following beneficial effects: The present application prepares melamine-formaldehyde resin microspheres, adsorbs sodium tungstate on the surface, reacts to generate tungsten oxide by adding concentrated hydrochloric acid dropwise, then forms a complexing agent-nickel complex on the surface by complexing nickel ions, and obtains dry gel by heating to prepare tungsten oxide / nickel oxide / melamine-formaldehyde resin microspheres. By heating and calcining, CO and NH3 generated by pyrolysis of the inner core melamine-formaldehyde resin microspheres act as reducing gases to reduce tungsten oxide and nickel oxide into tungsten-nickel alloy. The combination of the two has good stability and good compatibility. During the particle rearrangement stage, it can better break the balance of capillary force and cohesive force, promote liquid phase filling, and improve the performance of the tungsten-copper alloy. It can also be used as a metal catalyst to grow carbon nanotubes in situ on its surface using CO as a carbon source. No high-risk carbon source and reducing gas needs to be added, making it more convenient and operable. Under the action of ball milling, Janus nanosheets are prepared. One side of the nanosheet is a carbon nanotube layer, which has good affinity and compatibility with diamond. At the same time, the network structure has good heat conduction and electrical conductivity, which can significantly improve the dissipation of high heat during the operation of the wire saw and reduce static electricity. The other side is a tungsten-nickel alloy layer, which has good strength and hardness, improving the wear resistance and strength of the diamond modified wire saw. At the same time, since it is similar to the steel material of the wire saw, it is a cubic crystal structure, greatly improving its compatibility and affinity, and can be well mixed.

[0016] The diamond micro-powder treated by plasma treatment uses high-energy particles in the plasma to bombard the surface of the diamond, causing the surface atoms to rearrange or form active groups, thereby enhancing the interaction between the two. This allows the tungsten-nickel alloy / carbon nanotube Janus nanosheet to be stably fixed on the surface of the diamond powder. After adding the coating, it can significantly improve the adhesion to the steel material of the wire saw, thereby improving the hardness, strength, wear resistance, thermal conductivity, heat resistance, and anti-static performance of the wire saw, and significantly expanding the application range of the wire saw. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0018] Embodiment 1 The embodiment provides a preparation method of a composite diamond material, comprising the following steps: S1. 1.5 g of melamine, 1.5 g of formaldehyde, 95 mL of water, 0.4 g of polyvinyl alcohol and 0.15 g of oxalic acid are uniformly mixed, heated to 75 DEG C, stirred for 5 min, centrifuged, washed, dried, and melamine-formaldehyde resin microspheres are prepared; S2. 2 g of sodium tungstate is dissolved in 200 mL of water, 4 g of melamine-formaldehyde resin microspheres and 0.5 g of ammonium chloride are added, 1 g of concentrated hydrochloric acid is added dropwise, stirred and uniformly mixed, filtered, centrifuged, dried, and tungsten oxide@melamine-formaldehyde resin microspheres are obtained; S3. 10 g of tungsten oxide / melamine-formaldehyde resin microspheres are added into a solution containing 2 g of nickel chloride, uniformly dispersed, 3 g of sodium citrate is added, heated to 50 DEG C, and the solvent is evaporated to obtain a sol; then the temperature is increased to 120 DEG C, the vacuum degree is reduced to 0.01 MPa, and the dry gel is obtained, and the tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres are prepared by ball milling for 1 h; S4. The tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres are heated to 850 DEG C under argon protection, calcined for 60 min, ball milled for 3 h, and the tungsten-nickel alloy@carbon nanotube Janus nanosheet is prepared; S5. Diamond micro-powder is soaked in acetone, filtered, dried, and treated by plasma to obtain activated diamond micro-powder; The plasma treatment conditions are as follows: the hydrogen flow rate is 40 sccm, the oxygen flow rate is 60 sccm, the substrate temperature is 350 DEG C, the gas pressure is 3 kPa, the power is 600 W, and the time is 15 min; S6. 10 g of activated diamond micro-powder and 4 g of tungsten-nickel alloy@carbon nanotube Janus nanosheet are uniformly mixed, and the composite diamond material is prepared by ball milling treatment for 3 h.

[0019] Embodiment 2 The embodiment provides a preparation method of a composite diamond material, comprising the following steps: S1. 2.5 g of melamine, 2.5 g of formaldehyde, 105 mL of water, 0.6 g of polyvinyl alcohol and 0.25 g of oxalic acid are uniformly mixed, heated to 85 DEG C, stirred for 15 min, centrifuged, washed, dried, and melamine-formaldehyde resin microspheres are prepared; S2. Dissolve 4 g of sodium tungstate in 200 mL of water, add 6 g of melamine-formaldehyde resin microspheres and 1 g of ammonium chloride, drop 2 g of concentrated hydrochloric acid, stir and mix uniformly, filter, centrifuge, dry, and obtain tungsten oxide@melamine-formaldehyde resin microspheres; S3. Add 10 g of tungsten oxide / melamine-formaldehyde resin microspheres to 150 mL of a solution containing 4 g of nickel nitrate, disperse uniformly, add 5 g of citric acid, heat to 70℃, evaporate the solvent, and obtain a sol; then increase the temperature to 150℃, reduce the vacuum degree to 0.1 MPa, and obtain a xerogel, ball mill for 2 h, and prepare tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres; S4. Heat the tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres to 950℃ under argon protection, calcine for 90 min, ball mill for 5 h, and prepare tungsten-nickel alloy@carbon nanotube Janus nanosheets; S5. Soak the diamond micro-powder in acetone, filter, dry, and treat by plasma to obtain activated diamond micro-powder; The conditions of the plasma treatment are as follows: hydrogen flow rate is 60 sccm, oxygen flow rate is 40 sccm, substrate temperature is 450℃, gas pressure is 4 kPa, power is 700 W, and time is 25 min; S6. Mix 10 g of activated diamond micro-powder and 7 g of tungsten-nickel alloy@carbon nanotube Janus nanosheets uniformly, and ball mill for 5 h to prepare a composite diamond material.

[0020] Example 3 The embodiment provides a preparation method of a composite diamond material, including the following steps: S1. Mix 2 g of melamine, 2 g of formaldehyde, 100 mL of water, 0.5 g of polyvinyl alcohol, and 0.2 g of oxalic acid uniformly, heat to 80℃, stir and react for 10 min, centrifuge, wash, dry, and prepare melamine-formaldehyde resin microspheres; S2. Dissolve 3 g of sodium tungstate in 200 mL of water, add 5 g of melamine-formaldehyde resin microspheres and 0.7 g of ammonium chloride, drop 1.5 g of concentrated hydrochloric acid, stir and mix uniformly, filter, centrifuge, dry, and obtain tungsten oxide@melamine-formaldehyde resin microspheres; S3. Add 10 g of tungsten oxide / melamine-formaldehyde resin microspheres to 150 mL of a solution containing 3 g of nickel nitrate, disperse uniformly, add 4 g of citric acid, heat to 60℃, evaporate the solvent, and obtain a sol; then increase the temperature to 135℃, reduce the vacuum degree to 0.05 MPa, and obtain a xerogel, ball mill for 1.5 h, and prepare tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres; S4. The tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres were heated to 900 DEG C under argon protection, calcined for 75 min, and ball milled for 4 h to obtain tungsten-nickel alloy@carbon nanotube Janus nanoplatelets; S4. The tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres were heated to 900 DEG C under argon protection, calcined for 75 min, and ball milled for 4 h to obtain tungsten-nickel alloy@carbon nanotube Janus nanoplatelets; The plasma treatment conditions were as follows: hydrogen flow rate 50 sccm, oxygen flow rate 50 sccm, substrate temperature 400 DEG C, gas pressure 3.5 kPa, power 650 W, and time 20 min; S6. 10 g of the activated diamond powder and 5.5 g of the tungsten-nickel alloy@carbon nanotube Janus nanoplatelets were uniformly mixed and ball milled for 4 h to obtain the composite diamond material.

[0021] Comparative Example 1 Compared with Example 3, the difference is that step S2 is not performed.

[0022] The details are as follows: S1. 2 g of melamine, 2 g of formaldehyde, 100 mL of water, 0.5 g of polyvinyl alcohol, and 0.2 g of oxalic acid were uniformly mixed, heated to 80 DEG C, stirred for 10 min, centrifuged, washed, and dried to obtain melamine-formaldehyde resin microspheres; S2. 10 g of the melamine-formaldehyde resin microspheres were added to 150 mL of a solution containing 3 g of nickel nitrate, uniformly dispersed, 4 g of citric acid was added, heated to 60 DEG C, and the solvent was evaporated to obtain a sol; then the temperature was increased to 135 DEG C and the vacuum degree was reduced to 0.05 MPa to obtain a xerogel, which was ball milled for 1.5 h to obtain nickel oxide@melamine-formaldehyde resin microspheres; S3. The nickel oxide@melamine-formaldehyde resin microspheres were heated to 900 DEG C under argon protection, calcined for 75 min, and ball milled for 4 h to obtain nickel@carbon nanotube Janus nanoplatelets; S4. The diamond powder was soaked in acetone, filtered, dried, and subjected to plasma treatment to obtain activated diamond powder; The plasma treatment conditions were as follows: hydrogen flow rate 50 sccm, oxygen flow rate 50 sccm, substrate temperature 400 DEG C, gas pressure 3.5 kPa, power 650 W, and time 20 min; S5. 10 g of the activated diamond powder and 5.5 g of the nickel@carbon nanotube Janus nanoplatelets were uniformly mixed and ball milled for 4 h to obtain the composite diamond material.

[0023] Comparative Example 2 Compared with Example 3, the difference is that step S3 is not performed.

[0024] The details are as follows: S1. Mix 2 g of melamine, 2 g of formaldehyde, 100 mL of water, 0.5 g of polyvinyl alcohol, and 0.2 g of oxalic acid. Heat to 80°C, stir for 10 min, centrifuge, wash, and dry to produce melamine-formaldehyde resin microspheres. S2. Dissolve 3g of sodium tungstate in 200mL of water, add 5g of melamine-formaldehyde resin microspheres and 0.7g of ammonium chloride, add 1.5g of concentrated hydrochloric acid dropwise, stir and mix, filter, centrifuge, and dry to obtain tungsten oxide @ melamine-formaldehyde resin microspheres; S3. Tungsten oxide@melamine-formaldehyde resin microspheres were heated to 900°C under argon, calcined for 75 minutes, and ball-milled for 4 hours to produce tungsten@carbon nanotube Janus nanosheets. S4. The diamond powder was soaked in acetone, filtered, dried, and plasma treated to obtain activated diamond powder; The plasma treatment conditions are as follows: a hydrogen flow rate of 50 sccm, an oxygen flow rate of 50 sccm, a substrate temperature of 400°C, a gas pressure of 3.5 kPa, a power of 650 W, and a time of 20 min; S5. 10 g of activated diamond powder and 5.5 g of tungsten-carbon nanotube Janus nanosheets were mixed and ball-milled for 4 h to produce a composite diamond material.

[0025] Comparative Example 3 Compared with embodiment 3, the difference is that step S5 is not performed.

[0026] The details are as follows: S1. Mix 2 g of melamine, 2 g of formaldehyde, 100 mL of water, 0.5 g of polyvinyl alcohol, and 0.2 g of oxalic acid. Heat to 80°C, stir for 10 min, centrifuge, wash, and dry to produce melamine-formaldehyde resin microspheres. S2. Dissolve 3g of sodium tungstate in 200mL of water, add 5g of melamine-formaldehyde resin microspheres and 0.7g of ammonium chloride, add 1.5g of concentrated hydrochloric acid dropwise, stir and mix, filter, centrifuge, and dry to obtain tungsten oxide @ melamine-formaldehyde resin microspheres; S3. 10 g of tungsten oxide / melamine-formaldehyde resin microspheres were added to 150 mL of a solution containing 3 g of nickel nitrate and dispersed evenly. 4 g of citric acid was added and the solution was heated to 60°C to evaporate the solvent to obtain a sol. The temperature was then raised to 135°C and the vacuum level was reduced to 0.05 MPa to obtain a xerogel. This was ball-milled for 1.5 h to obtain tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres. S4. The tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres were heated to 900℃ under argon protection, calcined for 75 min, and ball milled for 4 h to obtain tungsten-nickel alloy@carbon nanotube Janus nanosheets; S5. 10 g of diamond micro-powder and 5.5 g of tungsten-nickel alloy@carbon nanotube Janus nanosheets were uniformly mixed and ball milled for 4 h to obtain a composite diamond material.

[0027] Comparative Example 4 Compared with Example 3, the difference is that the tungsten-nickel alloy@carbon nanotube Janus nanosheets are replaced by equal mass of carbon nanotube powder.

[0028] Comparative Example 5 Compared with Example 3, the difference is that the tungsten-nickel alloy@carbon nanotube Janus nanosheets are replaced by equal mass of tungsten-nickel alloy powder.

[0029] Preparation method of tungsten-nickel alloy: 3 g of sodium tungstate was dissolved in 200 mL of water, 0.7 g of ammonium chloride was added, 1.5 g of concentrated hydrochloric acid was added dropwise, and the mixture was stirred and mixed uniformly, filtered, centrifuged, and dried to obtain tungsten oxide powder; S3. 10 g of tungsten oxide powder was added to a solution containing 3 g of nickel nitrate, dispersed uniformly, 4 g of citric acid was added, heated to 60℃, and the solvent was evaporated to obtain a sol; then the temperature was increased to 135℃ and the vacuum degree was reduced to 0.05 MPa to obtain a xerogel, the xerogel was ignited, and the tungsten-nickel alloy powder was obtained by calcination reduction under hydrogen atmosphere at 900℃ for 5 h.

[0030] Test Example 1 The composite diamond materials prepared in Examples 1-3 and Comparative Examples 1-5 were added to 5 wt% polyvinyl alcohol for granulation, and then pressed into a green body at 100 MPa. The green body was first heated to 700℃ at a rate of 5℃ / min for 1 h to remove the binder, then heated to 1500℃ at a rate of 3℃ / min for 3 h for sintering, and finally cooled to 250℃ at a rate of 4℃ / min, and then cooled to room temperature in the furnace. Performance tests were carried out, and the results are shown in Table 1.

[0031] The bending strength was tested by three-point bending method of Xww universal testing machine.

[0032] The hardness was tested by MC010 hardness tester, and the average value of 5 points was taken as the final hardness value.

[0033] The indentation method was selected to test the fracture toughness of the sample.

[0034] The thermal conductivity was tested by laser thermal conductivity instrument (DFX-500) (25℃).

[0035] Table 1

[0036] From the above table, it can be seen that the samples prepared from the composite diamond materials prepared in Examples 1-3 have good mechanical properties, hardness and thermal conductivity.

[0037] Test Example 2 The composite diamond materials prepared in Examples 1-3 and Comparative Examples 1-5 were added into a coating base to prepare a coating, which was stirred and mixed uniformly, and then uniformly coated on a core wire. The coated core wire was passed through a 145 μm diameter limiting die for diameter limiting, and then baked in a 100℃ hot field for 60 s. The baked core wire was cured by a light curing oven, and then collected to prepare a diamond modified wire saw, which was subjected to performance testing.

[0038] The formula of the coating is as follows: 40 wt% epoxy acrylate, 30 wt% polyether acrylate, 10 wt% polyester acrylate, 10 wt% composite diamond material, 2 wt% silicon oxide, 2 wt% silicon nitride, 5 wt% ethyl acetate and 1 wt% boron nitride.

[0039] The cutting efficiency was detected as follows: the prepared diamond modified wire saw was used to cut a silicon rod with a diameter of 100 mm at a wire speed of 2.5 m / s, a feeding speed of 0.5 mm / min and water as a cooling medium for 250 min, and the cutting efficiency of the diamond modified wire saw on the silicon rod and the firmness of the abrasive particles and the core wire were observed.

[0040] The flexibility test method was as follows: the prepared diamond modified wire saw was wound on a cylinder with a diameter of 10 mm, and then a microscope was used to check whether the coating surface of the diamond wire saw was cracked or peeled off.

[0041] The abrasion resistance test method was as follows: a GCr steel sheet (HRC=54) was used to scratch and grind the surface of the prepared diamond wire saw, and whether or not micro-powder was peeled off was observed.

[0042] The results are shown in Table 2.

[0043] Table 2

[0044] From the above table, it can be seen that the diamond modified wire saw prepared by adding the composite diamond materials prepared in Examples 1-3 into a coating and coating on a wire saw has good comprehensive performance.

[0045] The above description is merely preferred embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a composite diamond material, characterized in that: Melamine-formaldehyde resin microspheres were prepared, and tungsten oxide was loaded on the surface and complexed with nickel oxide to obtain tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres. After heating and calcining, tungsten-nickel alloy@carbon nanotube Janus nanosheets were obtained. The composite diamond material was obtained by mixing and ball milling with plasma-treated activated diamond micropowder.

2. The preparation method according to claim 1, characterized in that The following steps are involved: S1. Melamine, formaldehyde, water, polyvinyl alcohol, and oxalic acid were mixed, heated with stirring, centrifuged, washed, and dried to obtain melamine-formaldehyde resin microspheres; S2. Sodium tungstate was dissolved in water, melamine-formaldehyde resin microspheres and ammonium chloride were added, concentrated hydrochloric acid was added dropwise, stirred, filtered, centrifuged, and dried to obtain tungsten oxide @ melamine-formaldehyde resin microspheres; S3. Tungsten oxide / melamine-formaldehyde resin microspheres are added to a solution containing nickel salt and uniformly dispersed. A complexing agent is added and the solvent is evaporated by heating to obtain a sol. The temperature is then increased and the vacuum is reduced to obtain a xerogel. This is then ball-milled to obtain tungsten oxide / nickel oxide@melamine-formaldehyde resin microspheres. S4. The tungsten oxide / nickel oxide @ melamine-formaldehyde resin microspheres were heated and calcined under inert gas protection and ball milled to obtain tungsten-nickel alloy @ carbon nanotube Janus nanosheets; S5. The diamond powder was soaked in acetone, filtered, dried, and plasma treated to obtain activated diamond powder; S6. Activated diamond powder and tungsten-nickel alloy@carbon nanotube Janus nanosheets were uniformly mixed and ball-milled to produce a composite diamond material.

3. The preparation method according to claim 2, characterized in that The mass ratio of melamine, formaldehyde, water, polyvinyl alcohol and oxalic acid in step S1 is 1.5-2.5:1.5-2.5:95-105:0.4-0.6:0.15-0.25, and the heating and stirring reaction is carried out at a temperature of 75-85° C. and for 5-15 minutes.

4. The preparation method according to claim 2, characterized in that The mass ratio of sodium tungstate, melamine-formaldehyde resin microspheres, ammonium chloride and concentrated hydrochloric acid in step S2 is 2-4:4-6:0.5-1:1-2.

5. The preparation method according to claim 2, characterized in that In step S3, the mass ratio of the tungsten oxide / melamine-formaldehyde resin microspheres, the nickel salt, and the complexing agent is 10:2-4:3-5, the nickel salt is selected from at least one of nickel chloride, nickel sulfate, and nickel nitrate, the complexing agent is citric acid or sodium citrate, the heating temperature is 50-70°C, the temperature is increased to 120-150°C, and the vacuum degree is reduced to 0.01-0.1MPa; the ball milling time is 1-2h.

6. The preparation method according to claim 2, characterized in that The heating and calcining temperature in step S4 is 850-950° C., the time is 60-90 min, and the ball milling time is 3-5 h.

7. The preparation method according to claim 2, characterized in that The conditions for the plasma treatment in step S5 are: a hydrogen flow rate of 40-60 sccm, an oxygen flow rate of 40-60 sccm, a substrate temperature of 350-450° C., a gas pressure of 3-4 kPa, a power of 600-700 W, and a time of 15-25 min.

8. The preparation method according to claim 2, characterized in that In step S6, the mass ratio of the activated diamond micropowder to the tungsten-nickel alloy@carbon nanotube Janus nanosheets is 10:4-7, and the ball milling treatment time is 3-5 hours.

9. A composite diamond material obtained by the preparation method according to any one of claims 1 to 8.

10. A diamond modified wire saw, characterized in that: The composite diamond material according to claim 9 is added to a coating, coated on a wire saw, and cured to obtain a diamond-modified wire saw.

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