Efficient grinding diamond abrasive and preparation process thereof

Abstract

The invention relates to the field of abrasive materials, in particular to an efficient grinding diamond abrasive material and a preparation process thereof.The efficient grinding diamond abrasive material is prepared by coating diamond micro-powder for multiple times to prepare composite diamond micro-powder, then blending the composite diamond micro-powder with electrolytic copper powder, filler, a wetting agent and modified polyvinyl alcohol to obtain slurry, and conducting freezing-unfreezing gel forming to obtain the efficient grinding diamond abrasive material. The prepared diamond grinding material is good in water resistance and efficient in grinding; the preparation method comprises the following steps: depositing a tungsten coating on the surface of diamond micro-powder, then carrying out vacuum high-temperature treatment to obtain pretreated diamond micro-powder with a tungsten carbide layer growing in situ on the surface, generating a silicon oxide layer on the pretreated diamond micro-powder by using tetraethoxysilane, and then generating praseodymium-doped cerium oxide nanoparticles on the surface of the modified diamond micro-powder by using a homogeneous precipitation method; the preparation method comprises the following steps: carrying out chain extension treatment on a prepolymer generated by polytetrahydrofuran ether glycol and 4, 4 '-dicyclohexylmethane diisocyanate by using a silicon-containing chain extender to obtain a polyurethane prepolymer, and then modifying polyvinyl alcohol by using the polyurethane prepolymer and phenolic resin.

Description

Technical Field

[0001] The present invention relates to the technical field of abrasives, and specifically to a high-efficiency grinding diamond abrasive and its preparation process. Background Art

[0002] Silicon carbide materials have characteristics such as high thermal conductivity, wide bandgap, high breakdown voltage, strong radiation resistance, and good chemical stability. They are excellent substrate materials for manufacturing semiconductor devices. Existing epitaxial wafer substrate materials generally require advantages such as super-smooth flatness, defect-free and damage-free surfaces, etc. The surface processing quality is closely related to the device performance.

[0003] Ultra-fine diamond is an ideal polishing abrasive for silicon carbide materials. However, the agglomeration of ultra-fine diamond particles affects the surface quality of the material. When preparing abrasives by combining it with a binder, there are problems such as easy detachment of diamond, and the prepared abrasives cannot continuously and stably perform grinding, thus affecting the surface quality of the workpiece. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-efficiency grinding diamond abrasive and its preparation process to solve the problems in the prior art.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] A preparation process of a high-efficiency grinding diamond abrasive includes the following steps:

[0007] S1: Mix composite diamond micropowder, electrolytic copper powder, filler, and wetting agent, and add a blend of modified polyvinyl alcohol and deionized water to obtain a slurry.

[0008] S2: After sieving the slurry, pour it into a mold, cycle freeze, and heat up for curing to obtain a high-efficiency grinding diamond abrasive.

[0009] Further, the working conditions of cycle freezing are: cycle freeze at -20°C for 2 - 4 times; the working conditions of heat-up curing are: the temperature is 160°C.

[0010] Further, by mass fraction, the raw material composition of the slurry is: 18 - 26 parts of composite diamond micropowder, 37 - 43 parts of electrolytic copper powder, 6 - 13 parts of filler, 1 - 3 parts of wetting agent, 2 - 5 parts of deionized water, and 13 - 19 parts of modified polyvinyl alcohol.

[0011] Further, the filler is obtained by compounding alumina, zinc oxide, and graphite in a mass ratio of 2:1:1.

[0012] Further, the preparation of the composite diamond micropowder includes the following steps:

[0013] (1) Ultrasonically clean the diamond micropowder successively with acetone, ethanol, and deionized water, and then dry it. Then, deposit a 60 - 80 nm tungsten coating on the diamond surface by magnetron sputtering, and then perform vacuum high-temperature treatment to obtain pretreated diamond micropowder;

[0014] (2) Mix tetraethyl orthosilicate, absolute ethanol, and deionized water, keep it at 48 - 52 °C for 1 - 3 h, add the pretreated diamond micropowder, stir at 80 - 100 °C for 2 - 4 h, let it stand for precipitation, and dry to obtain modified diamond micropowder;

[0015] (3) Mix the modified diamond micropowder and absolute ethanol, ultrasonically oscillate for 8 - 10 min, add a mixed solution of cerium nitrate hexahydrate, praseodymium nitrate, hexamethylenetetramine, and deionized water, stir in a water bath at 70 - 75 °C for 1 - 2 h, centrifuge, wash, and dry, and calcine in an air atmosphere at 650 °C for 2 h to obtain composite diamond micropowder.

[0016] Aiming at the agglomeration problem of ultra-fine abrasive grains in traditional abrasives, the present invention modifies diamond micropowder to improve its dispersion uniformity. First, deposit a tungsten coating on the surface of diamond micropowder by magnetron sputtering, and then use vacuum high-temperature treatment to in-situ transform the tungsten coating on the surface of diamond micropowder into a tungsten carbide coating to obtain pretreated diamond micropowder, thereby improving the grinding performance of the abrasive. To further improve the polishing quality of the abrasive, tetraethyl orthosilicate is used as the silica precursor to synthesize silica-coated pretreated diamond micropowder as modified diamond micropowder, and then homogeneous precipitation method is used to generate praseodymium-doped cerium oxide nanoparticles on the surface of the modified diamond micropowder, thereby greatly improving the polishing effect of the abrasive.

[0017] Further, the preparation of the modified polyvinyl alcohol includes the following steps:

[0018] 1) Under a nitrogen atmosphere, mix polytetrahydrofuran ether diol, 4,4'-dicyclohexylmethane diisocyanate, and dibutyltin dilaurate, heat up to 78 - 82 °C and keep it for 1 - 2 h, cool down to 48 - 52 °C, add a silicon-containing chain extender, and heat up to 78 - 82 °C and keep it for 1 - 2 h to obtain a polyurethane prepolymer;

[0019] 2) Mix polyvinyl alcohol and deionized water, stir in a water bath at 95 - 100 °C for 3 - 4 h, add the polyurethane prepolymer and phenolic resin, stir for 5 - 10 min, add hydrochloric acid, formaldehyde, and a thickening agent, stir, and discharge to obtain the modified polyvinyl alcohol.

[0020] Further, the thickening agent is one of starch, pectin, agar, sodium carboxymethylcellulose, sodium polyacrylate, polyoxyethylene, and polyvinylpyrrolidone.

[0021] Further, the preparation of the silicon-containing chain extender includes the following steps:

[0022] Under a nitrogen atmosphere, eugenol, toluene, and Karstedt catalyst were mixed, and the temperature was raised to 60 °C. Then, 1,1,3,3-tetramethyldisiloxane was added, and the mixture was kept warm for 46 - 48 h. After rotary evaporation, a silicon-containing chain extender was obtained.

[0023] Furthermore, the mass ratio of polyvinyl alcohol, polyurethane prepolymer, and phenolic resin is 10:2:4.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] The present invention provides a high-efficiency grinding diamond abrasive and its preparation process. The diamond micropowder is subjected to multiple coating treatments to prepare composite diamond micropowder, and then it is blended with electrolytic copper powder, filler, wetting agent, and modified polyvinyl alcohol to obtain a slurry. Based on freeze-thaw gel forming, a water-resistant and high-efficiency grinding diamond abrasive is prepared.

[0026] In the present invention, electrolytic copper powder with good thermal conductivity and large ductility is introduced as an abrasive component, which can reduce local overheating in the polishing area while improving its wear resistance; alumina, graphite, and zinc oxide are introduced as fillers in the abrasive. Among them, alumina and zinc oxide can adjust the friction coefficient of the abrasive, and the introduction of graphite improves its heat resistance;

[0027] In order to improve the uniformity of the dispersion of diamond micropowder in the abrasive, the diamond micropowder is modified. First, a 60 - 80 nm tungsten coating is deposited on the surface of the diamond micropowder by magnetron sputtering, and then vacuum heat treatment is carried out to obtain pretreated diamond micropowder with an in-situ grown tungsten carbide layer on the surface, which helps to reduce abrasive clogging and improve its self-sharpening property. To further improve the polishing property of the abrasive, tetraethyl orthosilicate is used to form a silica layer on the pretreated diamond micropowder, and then homogeneous precipitation is used to form praseodymium-doped cerium oxide nanoparticles on the surface of the modified diamond micropowder, thereby greatly improving the polishing property and thermal stability of the abrasive.

[0028] In the present invention, polyvinyl alcohol is selected as the binder to prepare abrasives with high porosity and high self-sharpening property. However, polyvinyl alcohol has poor water resistance and problems such as difficult regulation of pore structure. To improve this situation, eugenol and 1,1,3,3-tetramethyldisiloxane are used as raw materials, and a silicon-containing chain extender is obtained under the catalysis of karstedt. Then, the prepolymer formed by polytetrahydrofuran ether diol and 4,4'-dicyclohexylmethane diisocyanate is chain-extended to obtain a polyurethane prepolymer. Then, the water-resistant polyurethane prepolymer and phenolic resin are used to modify the water resistance of polyvinyl alcohol and regulate the pore structure; the isocyanate groups in the polyurethane prepolymer and the hydroxymethyl groups in the phenolic resin react with the hydroxyl groups in polyvinyl alcohol, effectively improving the water resistance of polyvinyl alcohol. At the same time, the addition of a thickener can greatly increase the viscosity of the slurry after mixing with the abrasive, effectively improving the problem of abrasive settlement, increasing its porosity, providing sufficient chip space, effectively avoiding abrasive blockage, maintaining good self-sharpening property of the abrasive, and enabling the abrasive to grind continuously, stably and efficiently, thereby improving the polishing effect of the abrasive. Detailed implementation mode

[0029] The following will combine the embodiments of the present invention to clearly and completely describe the technical solutions in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention.

[0030] It should be noted that if there are directional indications such as up, down, left, right, front, and back in the embodiments of the present invention, the directional indications are only used to explain the relative position relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly. In addition, the technical solutions between the embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0031] The following further details the technical solutions of the present invention in combination with specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0032] Example 1: A preparation process for an efficient grinding diamond abrasive, including the following steps:

[0033] S1: Mix composite diamond micropowder, electrolytic copper powder, filler, and wetting agent, and add a blend of modified polyvinyl alcohol and deionized water to obtain a slurry;

[0034] By mass fraction, the raw material composition of the slurry is: 18 parts of composite diamond micropowder, 37 parts of electrolytic copper powder, 6 parts of filler, 1 part of wetting agent, 2 parts of deionized water, and 13 parts of modified polyvinyl alcohol;

[0035] The preparation of the composite diamond micropowder includes the following steps:

[0036] (1) Ultrasonically clean the diamond micropowder with acetone, ethanol, and deionized water in sequence and then dry it. Then, deposit a 70-nm tungsten coating on the diamond surface by magnetron sputtering, and then perform vacuum high-temperature treatment to obtain pretreated diamond micropowder;

[0037] (2) Mix 2.5 mL of tetraethyl orthosilicate, 80 mL of absolute ethanol, and 20 mL of deionized water, keep it at 48 °C for 3 h, add 1 g of pretreated diamond micropowder, stir at 80 °C for 4 h, let it stand for precipitation, and dry to obtain modified diamond micropowder;

[0038] (3) Mix 0.2 g of modified diamond micropowder and 48 mL of absolute ethanol, ultrasonically oscillate for 8 min, add a mixed solution of 0.5 g of cerium nitrate hexahydrate, 0.1 g of praseodymium nitrate, 1 g of hexamethylenetetramine, and 80 mL of deionized water, stir in a water bath at 70 °C for 2 h, perform centrifugal separation, washing, and drying, and calcine in an air atmosphere at 650 °C for 2 h to obtain composite diamond micropowder;

[0039] The preparation of the modified polyvinyl alcohol includes the following steps:

[0040] 1) Under a nitrogen atmosphere, mix 25 g of polytetrahydrofuran ether diol, 7.5 g of 4,4'-dicyclohexylmethane diisocyanate, and 0.3 g of dibutyltin dilaurate, heat up to 78 °C and keep it for 2 h, cool down to 48 °C, add 1.8 g of a silicon-containing chain extender, and heat up to 78 °C and keep it for 2 h to obtain a polyurethane prepolymer;

[0041] 2) Mix 10 g of polyvinyl alcohol and 100 mL of deionized water, stir in a water bath at 95 °C for 4 h, add 2 g of the polyurethane prepolymer and 4 g of phenolic resin, stir for 5 min, add 1.2 g of hydrochloric acid, 0.8 g of formaldehyde, and 2.5 g of thickener, stir, and discharge to obtain modified polyvinyl alcohol;

[0042] The preparation of the silicon-containing chain extender includes the following steps:

[0043] Under a nitrogen atmosphere, mix 0.34 g of eugenol, 40 mL of toluene, and 1.2 mg of karstedt catalyst, heat up to 60 °C, add 0.13 g of 1,1,3,3-tetramethyldisiloxane, continue to keep it warm for 46 h, and perform rotary evaporation to obtain the silicon-containing chain extender;

[0044] The thickener is polyvinylpyrrolidone;

[0045] The filler is obtained by compounding alumina, zinc oxide, and graphite in a mass ratio of 2:1:1;

[0046] S2: After sieving the slurry, pour it into a mold, freeze it cyclically, and then heat it up for curing to obtain a high-efficiency grinding diamond abrasive;

[0047] The working conditions for cyclic freezing are: cyclic freezing at -20°C for 2 times; the working conditions for heating and curing are: temperature of 160°C and time of 4 h.

[0048] Example 2: A preparation process of a high-efficiency grinding diamond abrasive, comprising the following steps:

[0049] S1: Mix composite diamond micropowder, electrolytic copper powder, filler, and wetting agent, and add a blend of modified polyvinyl alcohol and deionized water to obtain a slurry;

[0050] By mass fraction, the raw material composition of the slurry is: 22 parts of composite diamond micropowder, 41 parts of electrolytic copper powder, 9 parts of filler, 2 parts of wetting agent, 3 parts of deionized water, and 16 parts of modified polyvinyl alcohol;

[0051] The preparation of the composite diamond micropowder includes the following steps:

[0052] (1) Ultrasonically clean the diamond micropowder with acetone, ethanol, and deionized water in sequence and dry it, then deposit a 70-nm tungsten coating on the diamond surface by magnetron sputtering method, and then perform vacuum high-temperature treatment to obtain pretreated diamond micropowder;

[0053] (2) Mix 2.5 mL of tetraethyl orthosilicate, 80 mL of absolute ethanol, and 20 mL of deionized water, keep it at 50°C for 2 h, add 1 g of pretreated diamond micropowder, stir at 90°C for 3 h, let it stand for precipitation, and dry to obtain modified diamond micropowder;

[0054] (3) Mix 0.2 g of modified diamond micropowder and 48 mL of absolute ethanol, ultrasonically oscillate for 9 min, add a mixture of 0.5 g of cerium nitrate hexahydrate, 0.1 g of praseodymium nitrate, 1 g of hexamethylenetetramine, and 80 mL of deionized water, stir in a water bath at 72°C for 1.5 h, centrifuge, wash, and dry, and calcine in an air atmosphere at 650°C for 2 h to obtain composite diamond micropowder;

[0055] The preparation of the modified polyvinyl alcohol includes the following steps:

[0056] 1) Under a nitrogen atmosphere, mix 25 g of polytetrahydrofuran ether glycol, 7.5 g of 4,4'-dicyclohexylmethane diisocyanate, and 0.3 g of dibutyltin dilaurate, heat it up to 80°C and keep it warm for 1.5 h, cool it down to 50°C, add 1.8 g of a silicon-containing chain extender, and heat it up to 80°C and keep it warm for 1.5 h to obtain a polyurethane prepolymer;

[0057] 2) Mix 10 g of polyvinyl alcohol and 100 mL of deionized water, stir in a water bath at 98 °C for 3.5 h, add 2 g of polyurethane prepolymer and 4 g of phenolic resin, stir for 8 min, add 1.2 g of hydrochloric acid, 0.8 g of formaldehyde, and 2.5 g of thickener, stir, and discharge to obtain modified polyvinyl alcohol;

[0058] The preparation of the silicon-containing chain extender includes the following steps:

[0059] Under a nitrogen atmosphere, mix 0.34 g of eugenol, 40 mL of toluene, and 1.2 mg of karstedt catalyst, heat up to 60 °C, add 0.13 g of 1,1,3,3-tetramethyldisiloxane, continue to keep warm for 47 h, and perform rotary evaporation to obtain the silicon-containing chain extender;

[0060] The thickener is polyvinylpyrrolidone;

[0061] The filler is prepared by compounding alumina, zinc oxide, and graphite in a mass ratio of 2:1:1;

[0062] S2: After sieving the slurry, pour it into a mold, perform cyclic freezing, and heat up for curing to obtain a high-efficiency grinding diamond abrasive;

[0063] The working conditions for cyclic freezing are: cyclic freezing at -20 °C for 3 times; the working conditions for heating up for curing are: temperature of 160 °C and time of 4 h.

[0064] Example 3: A preparation process of a high-efficiency grinding diamond abrasive, including the following steps:

[0065] S1: Mix the composite diamond micropowder, electrolytic copper powder, filler, and wetting agent, and add the blend of modified polyvinyl alcohol and deionized water to obtain a slurry;

[0066] By mass, the raw material composition of the slurry is: 26 parts of composite diamond micropowder, 43 parts of electrolytic copper powder, 13 parts of filler, 3 parts of wetting agent, 5 parts of deionized water, and 19 parts of modified polyvinyl alcohol;

[0067] The preparation of the composite diamond micropowder includes the following steps:

[0068] (1) Ultrasonically clean the diamond micropowder with acetone, ethanol, and deionized water in sequence and dry it, then deposit a 70-nm tungsten coating on the diamond surface by magnetron sputtering, and then perform vacuum high-temperature treatment to obtain pretreated diamond micropowder;

[0069] (2) Mix 2.5 mL of tetraethyl orthosilicate, 80 mL of absolute ethanol, and 20 mL of deionized water, keep warm at 52 °C for 1 h, add 1 g of pretreated diamond micropowder, stir at 100 °C for 2 h, let it stand for precipitation, and dry to obtain modified diamond micropowder;

[0070] (3) Mix 0.2 g of modified diamond micropowder and 48 mL of absolute ethanol, ultrasonically oscillate for 10 min, add a mixed solution of 0.5 g of cerium nitrate hexahydrate, 0.1 g of praseodymium nitrate, 1 g of hexamethylenetetramine, and 80 mL of deionized water, stir in a water bath at 75 °C for 1 h, centrifuge, wash, and dry, and calcine in an air atmosphere at 650 °C for 2 h to obtain composite diamond micropowder;

[0071] The preparation of the modified polyvinyl alcohol includes the following steps:

[0072] 1) Under a nitrogen atmosphere, mix 25 g of polytetrahydrofuran ether glycol, 7.5 g of 4,4'-dicyclohexylmethane diisocyanate, and 0.3 g of dibutyltin dilaurate, heat up to 82 °C and keep warm for 1 h, cool down to 52 °C, add 1.8 g of a silicon-containing chain extender, and heat up to 82 °C and keep warm for 1 h to obtain a polyurethane prepolymer;

[0073] 2) Mix 10 g of polyvinyl alcohol and 100 mL of deionized water, stir in a water bath at 100 °C for 3 h, add 2 g of the polyurethane prepolymer and 4 g of phenolic resin, stir for 10 min, add 1.2 g of hydrochloric acid, 0.8 g of formaldehyde, and 2.5 g of a thickener, stir, and discharge to obtain modified polyvinyl alcohol;

[0074] The preparation of the silicon-containing chain extender includes the following steps:

[0075] Under a nitrogen atmosphere, mix 0.34 g of eugenol, 40 mL of toluene, and 1.2 mg of karstedt catalyst, heat up to 60 °C, add 0.13 g of 1,1,3,3-tetramethyldisiloxane, continue to keep warm for 48 h, and perform rotary evaporation to obtain the silicon-containing chain extender;

[0076] The thickener is polyvinylpyrrolidone;

[0077] The filler is prepared by compounding alumina, zinc oxide, and graphite in a mass ratio of 2:1:1;

[0078] S2: Pour the slurry through a sieve into a mold, perform cyclic freezing, and heat up for curing to obtain a high-efficiency grinding diamond abrasive;

[0079] The working conditions for cyclic freezing are: cyclic freezing at -20 °C for 4 times; the working conditions for heating up and curing are: temperature of 160 °C and time of 4 h.

[0080] Comparative Example 1: Using Example 3 as a control group, replace the composite diamond micropowder with diamond micropowder, and the other processes are normal.

[0081] Comparative Example 2: Using Example 3 as a control group, no polyurethane prepolymer is prepared, and the other processes are normal.

[0082] Source of raw materials (only for demonstration):

[0083] Electrolytic copper powder AM-Cu-002-4: Zhejiang Asia-America Nano-Tech Co., Ltd.; Wetting agent pe100: Guangzhou Hengyu Chemical Co., Ltd.; Diamond micropowder 0602047: Forsman Technology (Beijing) Co., Ltd.; Phenolic resin (99%, industrial grade): Wuhan Jixin Yibang Biotechnology Co., Ltd.; Tetraethyl orthosilicate T110594, Cerium nitrate hexahydrate C105378, Praseodymium nitrate P106054, Hexamethylenetetramine H431222, Poly(tetrahydrofuran) ether diol P118599, 4,4'-Dicyclohexylmethane diisocyanate D155475, Dibutyltin dilaurate D100274, Polyvinyl alcohol P139537, Formaldehyde F111939, Eugenol E110640, Karstedt catalyst K110178, 1,1,3,3-Tetramethyldisiloxane T110097, Alumina A406645, Graphite G434784, Zinc oxide Z431819: Shanghai Aladdin Biochemical Technology Co., Ltd.; Acetone, Ethanol, Hydrochloric acid, Toluene, analytical grade: Reagents of Sinopharm Group.

[0084] Performance test: The abrasives prepared in the examples and comparative examples were subjected to performance tests:

[0085] Flexural strength: The sample size was cut into a cylindrical shape with a diameter of 202 mm and a thickness of 4 mm, and a flexural testing machine was used to test the performance of the sample; Water resistance: The abrasive was soaked in water for 24 h, taken out and dried, and the flexural strength was measured again. If the change rate of the flexural strength was within 0-1%, it was considered qualified, otherwise it was unqualified; Polishing performance: The 4H-N silicon carbide wafer was used as the polishing object. The substrate was precision ground before polishing, and the average roughness was 0.065 μm. The parameters of the surface polishing machine were as follows: the outer diameter of the polishing disc was 280 mm, the working pressure of the polishing machine was 0.2 MPa, the rotation speed of the polishing disc was 120 r / min, the rotation speed of the workpiece holder was 30 r / min, the flow rate of the polishing fluid was 200 mL / min, the time was 8 min, the temperature was 20 °C, and the humidity was 50%. The surface roughness of the workpiece after polishing was measured using a white light interferometer; The test results are shown in Table 1;

[0086] Table 1

[0087]

[0088] The present invention provides a high-efficiency grinding diamond abrasive and its preparation process. The diamond micropowder is subjected to multiple coating treatments to prepare composite diamond micropowder, and then it is blended with electrolytic copper powder, filler, wetting agent, and modified polyvinyl alcohol to obtain a slurry. Based on freeze-thaw gel forming, a diamond abrasive with good water resistance and high grinding efficiency is prepared.

[0089] Example 3 was compared with Comparative Example 1. In order to improve the uniformity of the dispersion of diamond micropowder in the abrasive, the diamond micropowder was modified. First, a tungsten coating with a thickness of 60-80 nm was deposited on the surface of the diamond micropowder by magnetron sputtering, and then vacuum heat treatment was carried out to obtain pretreated diamond micropowder with a tungsten carbide layer grown in situ on the surface, which helped to reduce abrasive clogging and improve its self-sharpening property. To further improve the polishing property of the abrasive, a silica layer was formed on the pretreated diamond micropowder using tetraethyl orthosilicate, and then doped praseodymium cerium oxide nanoparticles were formed on the surface of the modified diamond micropowder by homogeneous precipitation method, thereby greatly improving the polishing property and thermal stability of the abrasive.

[0090] Example 3 was compared with Comparative Example 2. In the present invention, polyvinyl alcohol was selected as the binder to prepare an abrasive with high porosity and high self-sharpening property. However, polyvinyl alcohol has poor water resistance and problems such as difficult regulation of the pore structure. In the present invention, to improve this situation, eugenol and 1,1,3,3-tetramethyldisiloxane were used as raw materials to obtain a silicon-containing chain extender under the catalysis of karstedt, and then the prepolymer formed by polytetrahydrofuran ether glycol and 4,4'-dicyclohexylmethane diisocyanate was chain-extended to obtain a polyurethane prepolymer. Then, the water-resistant polyurethane prepolymer and phenolic resin were used to modify the water resistance of polyvinyl alcohol and adjust the pore structure; the isocyanate groups in the polyurethane prepolymer and the hydroxymethyl groups in the phenolic resin reacted with the hydroxyl groups in polyvinyl alcohol, effectively improving the water resistance of polyvinyl alcohol. At the same time, the addition of a thickening agent can greatly increase the viscosity of the slurry after mixing with the abrasive, effectively improving the problem of abrasive settlement, increasing its porosity, and providing sufficient chip space to effectively avoid abrasive clogging and maintain the good self-sharpening property of the abrasive, enabling the abrasive to continuously, stably and efficiently perform grinding, thereby improving the polishing effect of the abrasive.

[0091] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention. All equivalent structural transformations made using the specification of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A preparation process for high-efficiency grinding diamond abrasives, characterized in that: The steps include: S1: Mix composite diamond powder, electrolytic copper powder, filler and wetting agent, and add a mixed solution of modified polyvinyl alcohol and deionized water to obtain a slurry; S2: The slurry is sieved and poured into a mold, and then cyclically frozen and heated to solidify to obtain a high-efficiency diamond abrasive for grinding.

2. The process for preparing a high-efficiency diamond grinding abrasive according to claim 1, characterized in that: The working conditions of cyclic freezing are: cyclic freezing at -20℃ for 2-4 times; the working conditions of heating and curing are: temperature is 160℃.

3. The preparation process of a high-efficiency diamond grinding abrasive according to claim 1, characterized in that: The raw material composition of the slurry is as follows, by weight: 18-26 parts of composite diamond micropowder, 37-43 parts of electrolytic copper powder, 6-13 parts of filler, 1-3 parts of wetting agent, 2-5 parts of deionized water, and 13-19 parts of modified polyvinyl alcohol.

4. The process for preparing a high-efficiency diamond grinding abrasive according to claim 1, characterized in that: The filler is prepared by mixing aluminum oxide, zinc oxide and graphite in a mass ratio of 2:1:

1.

5. The process for preparing a high-efficiency diamond grinding abrasive according to claim 1, characterized in that: The preparation of the composite diamond micropowder comprises the following steps: (1) Ultrasonic cleaning and drying of diamond micropowder with acetone, ethanol and deionized water in sequence, and then depositing a 60-80 nm tungsten coating on the surface of diamond by magnetron sputtering, followed by vacuum high temperature treatment to obtain pretreated diamond micropowder; (2) Mix ethyl orthosilicate, anhydrous ethanol and deionized water, keep warm at 48-52°C for 1-3 hours, add pretreated diamond powder, stir at 80-100°C for 2-4 hours, let stand for precipitation, and dry to obtain modified diamond powder; (3) The modified diamond powder and anhydrous ethanol are mixed, ultrasonically vibrated for 8-10 minutes, and a mixture of cerium nitrate hexahydrate, praseodymium nitrate, hexamethylenetetramine and deionized water is added, stirred in a water bath at 70-75°C for 1-2 hours, centrifuged, washed, dried, and calcined in an air atmosphere at 650°C for 2 hours to obtain composite diamond powder.

6. The process for preparing a high-efficiency diamond grinding abrasive according to claim 1, characterized in that: The preparation of the modified polyvinyl alcohol comprises the following steps: 1) In a nitrogen atmosphere, polytetramethylene glycol, 4,4'-dicyclohexylmethane diisocyanate and dibutyltin dilaurate are mixed, the temperature is raised to 78-82°C and kept for 1-2 hours, the temperature is lowered to 48-52°C, a silicon-containing chain extender is added, the temperature is raised to 78-82°C and kept for 1-2 hours to obtain a polyurethane prepolymer; 2) Mix polyvinyl alcohol and deionized water, stir in a water bath at 95-100°C for 3-4 hours, add polyurethane prepolymer and phenolic resin, stir for 5-10 minutes, add hydrochloric acid, formaldehyde and thickener, stir, and discharge to obtain modified polyvinyl alcohol.

7. The process for preparing a high-efficiency diamond grinding abrasive according to claim 6, characterized in that: The thickener is one of starch, pectin, agar, sodium carboxymethyl cellulose, sodium polyacrylate, polyoxyethylene and polyvinyl pyrrolidone.

8. The process for preparing a high-efficiency diamond grinding abrasive according to claim 6, characterized in that: The preparation of the silicon-containing chain extender comprises the following steps: In a nitrogen atmosphere, eugenol, toluene and Karstedt catalyst were mixed, the temperature was raised to 60°C, 1,1,3,3-tetramethyldisiloxane was added, the temperature was kept for 46-48 hours, and the silicon-containing chain extender was obtained by rotary evaporation.

9. The process for preparing a high-efficiency diamond grinding abrasive according to claim 6, characterized in that: The mass ratio of the polyvinyl alcohol, the polyurethane prepolymer and the phenolic resin is 10:2:

4.

10. A high-efficiency diamond abrasive for grinding, characterized in that: The invention is prepared by the preparation process according to any one of claims 1 to 9.

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