A high-efficiency diamond grinding abrasive and its preparation process

Abstract

The invention relates to the field of abrasives, and in particular to a high-efficiency grinding diamond abrasive and a preparation process thereof. Diamond micropowder is subjected to multiple coating treatments to prepare composite diamond micropowder, which is then blended with electrolytic copper powder, a filler, a wetting agent, and modified polyvinyl alcohol to obtain a slurry. The slurry is formed by freeze-thaw gel formation to prepare a high-efficiency grinding diamond abrasive with good water resistance. A tungsten coating is deposited on the surface of the diamond micropowder, followed by vacuum high-temperature treatment to obtain a pretreated diamond micropowder with a tungsten carbide layer grown in situ on the surface. Tetraethyl orthosilicate is used to generate a silicon oxide layer on the pretreated diamond micropowder, and then a homogeneous precipitation method is used to generate praseodymium-doped cerium oxide nanoparticles on the surface of the modified diamond micropowder. A prepolymer generated from polytetramethylene ether glycol and 4,4'-dicyclohexylmethane diisocyanate is chain extended using a silicon-containing chain extender to obtain a polyurethane prepolymer, and then the polyvinyl alcohol is modified using the polyurethane prepolymer and a phenolic resin.

Description

Technical Field

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

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

[0003] Ultrafine diamond is an ideal polishing abrasive for silicon carbide materials. However, the agglomeration of ultrafine diamond particles affects the surface quality of the material. When it is prepared with a binder to prepare abrasives, there are problems such as easy loss of diamonds. In addition, the prepared abrasive cannot be ground continuously and stably, 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 diamond grinding abrasive and a preparation process thereof, so as to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A preparation process for high-efficiency grinding of diamond abrasives comprises the following steps:

[0007] S1: Mixing composite diamond powder, electrolytic copper powder, filler, and wetting agent, and adding a blend of modified polyvinyl alcohol and deionized water to obtain a slurry;

[0008] S2: The slurry is sieved and poured into a mold, and then cyclically frozen and heated to solidify to obtain a high-efficiency diamond grinding abrasive.

[0009] Furthermore, the working conditions of cyclic freezing are: cyclic freezing at -20°C for 2-4 times; the working conditions of heating and curing are: temperature at 160°C.

[0010] Furthermore, the raw material composition of the slurry is, by mass, 18-26 parts of composite diamond powder, 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] Furthermore, the filler is a mixture of aluminum oxide, zinc oxide, and graphite in a mass ratio of 2:1:1.

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

[0013] (1) The diamond powder is ultrasonically cleaned and dried with acetone, ethanol, and deionized water in sequence, and then a 60-80 nm tungsten coating is deposited on the diamond surface by magnetron sputtering, followed by vacuum high-temperature treatment to obtain pretreated diamond powder;

[0014] (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 to precipitate, and dry to obtain modified diamond powder;

[0015] (3) The modified diamond micropowder and anhydrous ethanol were mixed, ultrasonically vibrated for 8-10 minutes, and a mixture of cerium nitrate hexahydrate, praseodymium nitrate, hexamethylenetetramine, and deionized water was added. The mixture was stirred in a water bath at 70-75°C for 1-2 hours, centrifuged, washed, and dried, and calcined in an air atmosphere at 650°C for 2 hours to obtain composite diamond micropowder.

[0016] To address the agglomeration problem of ultrafine abrasive particles in traditional abrasives, the present invention modifies diamond micropowder to improve its dispersion uniformity. First, a tungsten coating is deposited on the surface of the diamond micropowder using magnetron sputtering. Then, the tungsten coating on the surface of the diamond micropowder is converted in situ into a tungsten carbide coating using vacuum high-temperature treatment to obtain pretreated diamond micropowder, thereby improving the grinding performance of the abrasive. To further improve the polishing quality of the abrasive, ethyl orthosilicate is used as a silica precursor to synthesize silica-coated pretreated diamond micropowder as modified diamond micropowder. Then, a homogeneous precipitation method is used to generate praseodymium-doped cerium oxide nanoparticles on the surface of the modified diamond micropowder, thereby significantly improving the polishing effect of the abrasive.

[0017] Furthermore, the preparation of modified polyvinyl alcohol comprises the following steps:

[0018] 1) Under a nitrogen atmosphere, polytetramethylene glycol, 4,4'-dicyclohexylmethane diisocyanate, and dibutyltin dilaurate are mixed, heated to 78-82°C and kept warm for 1-2 hours, cooled to 48-52°C, a silicon-containing chain extender is added, and the temperature is raised to 78-82°C and kept warm for 1-2 hours 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 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.

[0020] Furthermore, the thickener is one of starch, pectin, agar, sodium carboxymethyl cellulose, sodium polyacrylate, polyoxyethylene, and polyvinyl pyrrolidone.

[0021] Furthermore, the preparation of the silicon-containing chain extender comprises the following steps:

[0022] Under nitrogen atmosphere, eugenol, toluene and Karstedt catalyst were mixed, heated to 60°C, 1,1,3,3-tetramethyldisiloxane was added, and the mixture was kept warm for 46-48 hours and rotary evaporated to obtain a silicon-containing chain extender.

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

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

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

[0026] The present invention introduces electrolytic copper powder with good thermal conductivity and high ductility as an abrasive component, which reduces local overheating in the polishing area while improving its wear resistance. Aluminum oxide, graphite, and zinc oxide are introduced into the abrasive as fillers, wherein aluminum oxide 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 diamond powder dispersion in the abrasive, the diamond powder is modified. First, a 60-80nm tungsten coating is deposited on the surface of the diamond powder by magnetron sputtering, and then vacuum high-temperature treatment is performed to obtain pretreated diamond powder with an in-situ growth of a tungsten carbide layer on the surface. This helps to reduce abrasive clogging and improve its self-sharpening properties. To further improve the polishing properties of the abrasive, ethyl orthosilicate is used to generate a silicon oxide layer on the pretreated diamond powder. Then, a homogeneous precipitation method is used to generate praseodymium-doped cerium oxide nanoparticles on the surface of the modified diamond powder, thereby significantly improving the polishing properties and thermal stability of the abrasive.

[0028] In the present invention, polyvinyl alcohol is selected as a binder to prepare an abrasive with high porosity and high self-sharpening property. However, polyvinyl alcohol has poor water resistance and has problems such as difficult to control the pore structure. In order to improve this situation, the present invention uses eugenol and 1,1,3,3-tetramethyldisiloxane as raw materials, obtains a silicon-containing chain extender under Karstedt catalysis, and then performs chain extension treatment on the prepolymer generated by polytetramethylene ether glycol and 4,4'-dicyclohexylmethane diisocyanate to obtain a polyurethane prepolymer. Then, the water-resistant polyurethane prepolymer and phenol are used to prepare the abrasive with high porosity and high self-sharpening property. The formaldehyde resin modifies the water resistance of polyvinyl alcohol and adjusts its pore structure; the isocyanate group in the polyurethane prepolymer and the hydroxymethyl group in the phenolic resin react with the hydroxyl group in the polyvinyl alcohol, effectively improving the water resistance of the polyvinyl alcohol. At the same time, the addition of the thickener can greatly increase the viscosity of the slurry after mixing it with the abrasive, effectively improve the abrasive sedimentation problem, increase its porosity, and provide it with sufficient chip space, which can effectively avoid abrasive clogging, maintain good self-sharpening properties of the abrasive, and enable the abrasive to grind continuously, stably and efficiently, thereby improving the polishing effect of the abrasive. DETAILED DESCRIPTION

[0029] The following will provide a clear and complete description of the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0030] It should be noted that if the embodiments of the present invention involve directional indications such as up, down, left, right, front, and back, such directional indications are only used to explain a specific posture, such as the relative position relationship between components, the movement status, etc. If the specific posture changes, the directional indication will also change accordingly. In addition, the technical solutions between the various embodiments may be combined with each other, but they must be based on the premise that they can be implemented by ordinary technicians in this field. If the combination of technical solutions is mutually inconsistent or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0031] The technical solutions of the present invention are further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely used to explain the present invention and are not intended to limit the present invention.

[0032] Example 1: A process for preparing a high-efficiency diamond grinding abrasive, comprising the following steps:

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

[0034] The raw material composition of the slurry is as follows: 18 parts of composite diamond powder, 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 comprises the following steps:

[0036] (1) The diamond powder was ultrasonically cleaned and dried with acetone, ethanol, and deionized water in sequence, and then a 70 nm tungsten coating was deposited on the diamond surface by magnetron sputtering, followed by vacuum high-temperature treatment to obtain pretreated diamond powder;

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

[0038] (3) 0.2 g of modified diamond powder and 48 mL of anhydrous ethanol were mixed and ultrasonically vibrated for 8 min. 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 was added. The mixture was stirred in a water bath at 70 ° C for 2 h, centrifuged, washed, and dried. The mixture was calcined in an air atmosphere at 650 ° C for 2 h to obtain composite diamond powder.

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

[0040] 1) Under nitrogen atmosphere, 25 g of polytetramethylene glycol, 7.5 g of 4,4'-dicyclohexylmethane diisocyanate, and 0.3 g of dibutyltin dilaurate were mixed, heated to 78°C and kept warm for 2 h, cooled to 48°C, 1.8 g of a silicon-containing chain extender was added, and the temperature was raised to 78°C and kept warm 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 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 comprises the following steps:

[0043] Under nitrogen atmosphere, 0.34 g of eugenol, 40 mL of toluene, and 1.2 mg of Karstedt catalyst were mixed, heated to 60°C, 0.13 g of 1,1,3,3-tetramethyldisiloxane was added, and the mixture was kept warm for 46 h and rotary evaporated to obtain a silicon-containing chain extender;

[0044] The thickener is polyvinyl pyrrolidone;

[0045] The filler is a mixture of aluminum oxide, zinc oxide and graphite in a mass ratio of 2:1:1;

[0046] 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;

[0047] The working conditions of cyclic freezing are: cyclic freezing twice at -20℃; the working conditions of heating and curing are: temperature at 160℃, time for 4h.

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

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

[0050] The raw material composition of the slurry is as follows: 22 parts of composite diamond powder, 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 comprises the following steps:

[0052] (1) The diamond powder was ultrasonically cleaned and dried with acetone, ethanol, and deionized water in sequence, and then a 70 nm tungsten coating was deposited on the diamond surface by magnetron sputtering, followed by vacuum high-temperature treatment to obtain pretreated diamond powder;

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

[0054] (3) 0.2 g of modified diamond powder and 48 mL of anhydrous ethanol were mixed and ultrasonically vibrated for 9 min. 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 was added. The mixture was stirred in a water bath at 72 °C for 1.5 h, centrifuged, washed, and dried. The mixture was calcined in an air atmosphere at 650 °C for 2 h to obtain composite diamond powder.

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

[0056] 1) Under a nitrogen atmosphere, 25 g of polytetramethylene glycol, 7.5 g of 4,4'-dicyclohexylmethane diisocyanate, and 0.3 g of dibutyltin dilaurate were mixed, heated to 80°C and kept warm for 1.5 h, cooled to 50°C, 1.8 g of a silicon-containing chain extender was added, and the temperature was raised to 80°C and kept 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 comprises the following steps:

[0059] Under nitrogen atmosphere, 0.34 g of eugenol, 40 mL of toluene, and 1.2 mg of Karstedt catalyst were mixed, heated to 60°C, 0.13 g of 1,1,3,3-tetramethyldisiloxane was added, and the mixture was kept warm for 47 h and rotary evaporated to obtain a silicon-containing chain extender;

[0060] The thickener is polyvinyl pyrrolidone;

[0061] The filler is a mixture of aluminum oxide, zinc oxide and graphite in a mass ratio of 2:1:1;

[0062] 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;

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

[0064] Example 3: A preparation process for high-efficiency grinding of diamond abrasives, comprising the following steps:

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

[0066] The raw material composition of the slurry is as follows: 26 parts of composite diamond powder, 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 comprises the following steps:

[0068] (1) The diamond powder was ultrasonically cleaned and dried with acetone, ethanol, and deionized water in sequence, and then a 70 nm tungsten coating was deposited on the diamond surface by magnetron sputtering, followed by vacuum high-temperature treatment to obtain pretreated diamond powder;

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

[0070] (3) 0.2 g of modified diamond powder and 48 mL of anhydrous ethanol were mixed and ultrasonically vibrated for 10 min. 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 was added. The mixture was stirred in a water bath at 75 ° C for 1 h, centrifuged, washed, and dried. The mixture was calcined in an air atmosphere at 650 ° C for 2 h to obtain composite diamond powder.

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

[0072] 1) Under a nitrogen atmosphere, 25 g of polytetramethylene glycol, 7.5 g of 4,4'-dicyclohexylmethane diisocyanate, and 0.3 g of dibutyltin dilaurate were mixed, heated to 82°C and kept warm for 1 hour, cooled to 52°C, 1.8 g of a silicon-containing chain extender was added, and the temperature was raised to 82°C and kept warm for 1 hour 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 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 thickener, stir, and discharge to obtain modified polyvinyl alcohol;

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

[0075] Under nitrogen atmosphere, 0.34 g of eugenol, 40 mL of toluene, and 1.2 mg of Karstedt catalyst were mixed, heated to 60°C, 0.13 g of 1,1,3,3-tetramethyldisiloxane was added, and the mixture was kept warm for 48 h, and rotary evaporated to obtain a silicon-containing chain extender;

[0076] The thickener is polyvinyl pyrrolidone;

[0077] The filler is a mixture of aluminum oxide, zinc oxide and graphite in a mass ratio of 2:1:1;

[0078] 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;

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

[0080] Comparative Example 1: Taking Example 3 as the control group, diamond micropowder was used to replace the composite diamond micropowder, and the other processes were normal.

[0081] Comparative Example 2: Example 3 was used as the control group, in which no polyurethane prepolymer was prepared and the other processes were normal.

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

[0083] Electrolytic copper powder AM-Cu-002-4: Zhejiang Yamei Nanotechnology 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, polytetramethylene ether glycol P118599, 4,4'-bicyclo[3-(4-(4-nitropropene)-1,4-dihydro ... Hexylmethane 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: Sinopharm Group reagents.

[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 the sample performance was tested using a flexural testing machine; Water resistance: The abrasive was soaked in water for 24 hours, taken out and dried, and the flexural strength was measured again. If the flexural strength change rate was between 0-1%, it was qualified, otherwise it was unqualified; Polishability: 4H-N silicon carbide wafers were used as the polishing object. The substrate was precision ground before polishing, with an average roughness of 0.065 μm. The parameters of the plane 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 polishing disc speed was 120 r / min, the workpiece holder speed was 30 r / min, the flow rate of the polishing liquid 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 tested using a white light interferometer; the test results are shown in Table 1;

[0086] Table 1

[0087]

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

[0089] Example 3 is compared with Comparative Example 1. In order to improve the uniformity of the dispersion of diamond powder in the abrasive, the diamond powder is modified. A 60-80 nm tungsten coating is first deposited on the surface of the diamond powder by magnetron sputtering. Then, the diamond powder is subjected to vacuum high-temperature treatment to obtain a pretreated diamond powder with an in-situ growth of a tungsten carbide layer on the surface. This helps to reduce abrasive clogging and improve its self-sharpening properties. To further improve the polishing properties of the abrasive, a silicon oxide layer is generated on the pretreated diamond powder using tetraethyl orthosilicate. Then, praseodymium-doped cerium oxide nanoparticles are generated on the surface of the modified diamond powder by a homogeneous precipitation method, thereby significantly improving the polishing properties and thermal stability of the abrasive.

[0090] Comparing Example 3 with Comparative Example 2, polyvinyl alcohol is selected as a binder in the present invention to prepare an abrasive with high porosity and high self-sharpening property. However, polyvinyl alcohol has poor water resistance and has problems such as difficult control of the pore structure. In order to improve this situation, the present invention uses eugenol and 1,1,3,3-tetramethyldisiloxane as raw materials, obtains a silicon-containing chain extender under Karstedt catalysis, and then performs chain extension treatment on the prepolymer generated by polytetramethylene ether glycol and 4,4'-dicyclohexylmethane diisocyanate to obtain a polyurethane prepolymer, and then uses water-resistant polysiloxane to obtain a polyurethane prepolymer. Urethane prepolymer and phenolic resin modify the water resistance of polyvinyl alcohol and adjust its pore structure; the isocyanate group in the polyurethane prepolymer and the hydroxymethyl group in the phenolic resin react with the hydroxyl group in the polyvinyl alcohol to effectively improve the water resistance of the polyvinyl alcohol. At the same time, the addition of the thickener can greatly increase the viscosity of the slurry after mixing it with the abrasive, effectively improve the problem of abrasive particle sedimentation, increase its porosity, and provide it with sufficient chip holding space, which can effectively avoid abrasive clogging, maintain the good self-sharpening property of the abrasive, and enable the abrasive to grind continuously, stably and efficiently, thereby improving the polishing effect of the abrasive.

[0091] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structural transformations made using the present invention specification under the inventive concept of the present invention, or any direct / indirect application 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 of diamond abrasives, characterized in that: The steps include: S1: Mix composite diamond powder, electrolytic copper powder, filler, and wetting agent PE100, and add a blend 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; The working conditions for cyclic freezing are: 2-4 cycles of cyclic freezing at -20℃; the working conditions for heating and curing are: temperature 160℃; The raw material composition of the slurry is as follows: 18-26 parts of composite diamond powder, 37-43 parts of electrolytic copper powder, 6-13 parts of filler, 1-3 parts of wetting agent PE100, 2-5 parts of deionized water, and 13-19 parts of modified polyvinyl alcohol. The filler is a mixture of aluminum oxide, zinc oxide and graphite in a mass ratio of 2:1:1; The preparation of the composite diamond micropowder comprises the following steps: (1) The diamond powder is ultrasonically cleaned and dried with acetone, ethanol, and deionized water in sequence, and then a 60-80 nm tungsten coating is deposited on the diamond surface by magnetron sputtering, followed by vacuum high-temperature treatment to obtain pretreated diamond powder; (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 to precipitate, and dry to obtain modified diamond powder; (3) The modified diamond micropowder and anhydrous ethanol were mixed, ultrasonically vibrated for 8-10 minutes, and a mixture of cerium nitrate hexahydrate, praseodymium nitrate, hexamethylenetetramine, and deionized water was added. The mixture was stirred in a water bath at 70-75°C for 1-2 hours, centrifuged, washed, and dried, and calcined in an air atmosphere at 650°C for 2 hours to obtain composite diamond micropowder. The preparation of the modified polyvinyl alcohol comprises the following steps: 1) Under a nitrogen atmosphere, polytetramethylene glycol, 4,4'-dicyclohexylmethane diisocyanate, and dibutyltin dilaurate are mixed, heated to 78-82°C and kept warm for 1-2 hours, cooled to 48-52°C, a silicon-containing chain extender is added, and the temperature is raised to 78-82°C and kept warm 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; In the preparation of modified polyvinyl alcohol, the thickener is one of starch, pectin, agar, sodium carboxymethyl cellulose, sodium polyacrylate, polyoxyethylene, and polyvinyl pyrrolidone; The preparation of the silicon-containing chain extender comprises the following steps: Under a nitrogen atmosphere, eugenol, toluene, and Karstedt catalyst were mixed, heated to 60°C, 1,1,3,3-tetramethyldisiloxane was added, and the mixture was kept warm for 46-48 hours, and rotary evaporated to obtain a silicon-containing chain extender; The mass ratio of the polyvinyl alcohol, the polyurethane prepolymer and the phenolic resin is 10:2:

4.

2. A high-efficiency diamond grinding abrasive, characterized in that: The product is prepared by the preparation process described in claim 1.

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