Modified diamond abrasive, and preparation method therefor and use thereof

Abstract

The present invention belongs to the technical field of abrasives. Provided are a modified diamond abrasive, and a preparation method therefor and the use thereof. The preparation method for the modified diamond abrasive comprises: modifying a diamond abrasive by means of a silane coupling agent, so as to obtain a first abrasive; uniformly mixing the first abrasive, a polyamide acid solution and an ionic liquid, and then subjecting the mixture to spray granulation, so as to obtain a second abrasive; and subjecting the second abrasive to an imidization treatment, so as to obtain the modified diamond abrasive, wherein the viscosity of the polyamide acid solution is 200-900 cp. The obtained modified diamond abrasive has a high sphericity degree and a high mechanical strength, thereby effectively solving the problems of passivation and a grinding efficiency reduced along with same of a grinding blade of a traditional diamond abrasive.

Description

A modified diamond abrasive and its preparation method and application Technical Field

[0001] The present disclosure relates to the technical field of abrasives, and in particular to a modified diamond abrasive and a preparation method and application thereof. Background Art

[0002] With the advancement of high-tech and materials science, the demand for machining precision is increasing across various industries, especially for semiconductor materials, which require both high removal rates and high surface finish. Increasing the abrasive particle size to improve removal rates can degrade the surface quality of the polished part. To address this issue, secondary spherical abrasives, formed by the agglomeration of primary abrasives, are currently used for grinding and polishing. These abrasives offer high cutting force, sustained abrasiveness, and high self-sharpening properties. During the grinding and polishing process, the large size of the secondary spherical abrasives effectively improves grinding efficiency. After surface passivation, the abrasives fall off under pressure, exposing a new surface that can continue to provide cutting force. The falling small abrasives refine the surface of the polished part, ensuring a high surface finish. Diamond, with its high hardness and wear resistance, is often used to manufacture various superhard products for grinding, polishing, and cutting. However, diamond's inherent chemical inertness and poor bonding with binders can lead to poor mechanical strength and sphericity in secondary spherical abrasives, making them less suitable for grinding and polishing.

[0003] Summary of the Invention

[0004] The purpose of the present disclosure is to overcome the deficiencies of the prior art and to provide a modified diamond abrasive with high mechanical strength and sphericity, and a preparation method and application thereof.

[0005] To achieve the above objectives, the technical solution adopted in the present disclosure is: a method for preparing a modified diamond abrasive, comprising the following steps:

[0006] Modifying the diamond abrasive by using a silane coupling agent to obtain a first abrasive;

[0007] After uniformly mixing the first abrasive, the polyamic acid solution and the ionic liquid, spraying and granulating the mixture to obtain the second abrasive;

[0008] The second abrasive is subjected to imidization treatment to obtain a modified diamond abrasive;

[0009] The viscosity of the polyamic acid solution is 200-900 cp.

[0010] This invention modifies diamond abrasives using a silane coupling agent and polyamic acid, followed by imidization. A silicon oxide-polyimide layer is constructed on the diamond surface as a binder, improving the mechanical strength and sphericity of the modified diamond abrasive. During the grinding process, the diamond abrasive gradually breaks down along the binder interface under pressure. This not only makes the modified diamond abrasive self-sharpening, improving grinding efficiency, but also produces small-particle diamond abrasives that enhance the surface finish of polished parts. Furthermore, the improved diamond abrasives slowly release new grinding edges, providing continuous grinding force. This effectively addresses the problem of edge dulling and the resulting reduction in grinding efficiency associated with conventional diamond grinding methods.

[0011] In the process of improving diamond abrasives, the silane coupling agent can form a silicon oxide film on the diamond surface, which can enhance the bonding strength between the polyamic acid and the diamond abrasive. The second abrasive can be further enhanced by imidization to improve the mechanical strength of the modified diamond abrasive. In addition, the addition of an ionic liquid to the second abrasive can form intermolecular hydrogen bonds between the proton donor in the ionic liquid and the proton acceptor C=O on the imide ring, promoting orderly molecular stacking, increasing the strength of the binder, and further improving the mechanical strength of the modified diamond abrasive. The ionic liquid can also promote the imidization process of the polyamic acid, improving efficiency while reducing energy consumption. Finally, the ionic liquid and the silane coupling agent interact to improve the sphericity of the modified diamond abrasive.

[0012] In one embodiment, the viscosity of the polyamic acid solution is 200-900cp, for example, it can be 200cp, 300cp, 400cp, 500cp, 550cp, 600cp, 700cp, 800cp, 900cp, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 400-800cp.

[0013] In the present disclosure, the viscosity of the polyamic acid solution affects the sphericity and mechanical strength of the modified diamond abrasive. If the viscosity of the polyamic acid solution is too low, the mechanical strength and sphericity of the modified diamond abrasive are poor. If the viscosity of the polyamic acid solution is too high, the mechanical strength of the modified diamond abrasive does not increase significantly, and the sphericity of the modified diamond abrasive decreases. When the viscosity of the polyamic acid solution is 400-800cp, the mechanical strength and sphericity of the modified diamond abrasive are better.

[0014] In the present disclosure, the viscosity of the polyamic acid solution is measured by the rotation method in GB / T 10247-2008 at a test temperature of 25°C.

[0015] When other reaction parameters remain unchanged, the present disclosure adjusts the viscosity of the polyamic acid solution by controlling the reaction time and temperature during the preparation of the polyamic acid solution.

[0016] In one embodiment, the solid content of the polyamic acid solution is 10-30%; for example, it can be 10%, 12%, 15%, 17%, 20%, 23%, 25%, 28%, 30%, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 15-25%.

[0017] In the present application, the solid content of the polyamic acid solution refers to that the total mass of the dianhydride monomer and the diamine monomer is 10-30%, based on the mass of the polyamic acid solution being 100%.

[0018] In one embodiment, based on the solid content of the polyamic acid solution, the mass of the ionic liquid is 2-10% of the mass of the polyamic acid solution; for example, it can be 2%, 4%, 6%, 8%, 10%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable; preferably, it is 4-8%.

[0019] In the present disclosure, the content of ionic liquid is one of the key factors affecting the mechanical strength and sphericity of the modified diamond abrasive. If the content of ionic liquid is low, the effect of the ionic liquid is small, and the mechanical strength and sphericity of the modified diamond abrasive are low. If the content of ionic liquid is high, the mechanical strength and sphericity of the modified diamond abrasive will be significantly reduced.

[0020] In one embodiment, the mass ratio of the first abrasive to the polyamic acid solution is 1:1.2-1.5; for example, it can be 1:1.2, 1:1.3, 1:1.4, 1:1.5, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0021] In one embodiment, the mass ratio of the silane coupling agent to the diamond abrasive is 1:1-1.3, for example, 1:1.1, 1:1.2, or 1:1.3, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0022] Specifically, the preparation method of the first abrasive comprises the following steps: adding a silane coupling agent and a diamond abrasive into a solvent, reacting the mixture after ultrasonic treatment, and washing and drying the resulting reactant to obtain the first abrasive;

[0023] Specifically, the ultrasonication time can be 10-60 min, such as 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, but is not limited to the listed values.

[0024] Specifically, the reaction temperature is 50-100°C, such as 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, but is not limited to the listed values.

[0025] Specifically, the reaction time can be 3-12 h, for example, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, but is not limited to the listed values.

[0026] In the present disclosure, the drying method, temperature and time are not limited, as long as the product can be dried.

[0027] In one embodiment, the imidization treatment step is: under inert gas protection, keeping the second abrasive at a temperature of 90-120° C. for 30-60 minutes, then keeping it at a temperature of 220-280° C. for 10-30 minutes, and finally keeping it at a temperature of 330-360° C. for 10-30 minutes.

[0028] By sequentially increasing the temperature to perform imidization treatment on the second abrasive, the imidization treatment can further improve the mechanical strength of the modified diamond abrasive.

[0029] Specifically, the present invention discloses that during the imidization treatment process, the temperature rising rate is 5-10° C. / min.

[0030] In one embodiment, the polyamic acid solution is obtained by solution polymerization of a dianhydride monomer and a diamine monomer in an organic solvent, wherein the dianhydride monomer is at least one of pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and perylenetetracarboxylic dianhydride (PTDA), the diamine monomer is at least one of 4,4'-diaminodiphenyl ether (ODA), 3,4'-diaminodiphenyl ether (3,4'ODA) and 1,4-phenylenediamine (PPD), and the organic solvent is at least one of N,N-dimethylacetamide and N-methylpyrrolidone.

[0031] Specifically, the polymerization reaction temperature is 5-25° C., and the polymerization reaction time is 1-12 hours.

[0032] In one embodiment, the ionic liquid is an imidazolium ionic liquid and / or a pyridine ionic liquid.

[0033] Specifically, the anion in the ionic liquid is one of chlorine, bromine, tetrafluoroboric acid, hexafluorophosphoric acid, and bis(trifluoromethanesulfonyl)imide.

[0034] In one embodiment, the silane coupling agent is at least one of ethyl silicate, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane.

[0035] In one embodiment, the spray granulation parameters are: drying temperature of 300-400° C., nozzle pressure of 2-2.5 MPa, and nozzle diameter of 0.05-0.08 mm.

[0036] In another aspect, a modified diamond abrasive is provided, which is prepared by the method for preparing the modified diamond abrasive.

[0037] In another aspect, the invention provides a use of the modified diamond abrasive in preparing abrasive tools.

[0038] Compared with the prior art, the beneficial effects of the present disclosure are: through modification with silane coupling agent and polyimide, the sphericity and mechanical strength of the modified diamond abrasive are improved, which effectively solves the problem of blunting of the grinding edge and reduction of grinding efficiency of traditional diamond abrasive. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG1 is an infrared spectrum of the modified diamond abrasive of Example 1;

[0040] FIG2 is a scanning electron microscope image of the diamond abrasive of Example 1;

[0041] FIG3 is a scanning electron microscope image of the modified diamond abrasive of Example 1. DETAILED DESCRIPTION

[0042] In order to better illustrate the purpose, technical solutions and advantages of the present disclosure, the present disclosure will be further described below in conjunction with specific embodiments and comparative examples. Its purpose is to understand the content of the present disclosure in detail, rather than to limit the present disclosure. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of the present disclosure are all commonly used ordinary reagents and instruments.

[0043] The first polyamic acid solution was prepared in-house by adding 4,4'-diaminodiphenyl ether and pyromellitic dianhydride to N-methylpyrrolidone, stirring and reacting at 5°C for 10 hours to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 550 cp, wherein the molar ratio of pyromellitic dianhydride to 4,4'-diaminodiphenyl ether was 1:1;

[0044] The second polyamic acid solution was prepared in-house, and its preparation method was as follows: 3,4'-diaminodiphenyl ether and 3,3,4,4'-biphenyltetracarboxylic dianhydride were added to N,N-dimethylacetamide, and stirred at 5°C for 10 hours to obtain a polyamic acid solution with a solid content of 30% and a viscosity of 900 cp, wherein the molar ratio of 3,4'-diaminodiphenyl ether to 3,3,4,4'-biphenyltetracarboxylic dianhydride was 1:1;

[0045] The third polyamic acid solution was prepared in-house, and its preparation method was as follows: 1,4-phenylenediamine and perylenetetracarboxylic dianhydride were added to N-methylpyrrolidone, and stirred at 10°C for 10 hours to obtain a polyamic acid solution with a solid content of 10% and a viscosity of 200 cp, wherein the molar ratio of 1,4-phenylenediamine to perylenetetracarboxylic dianhydride was 1:1;

[0046] The fourth polyamic acid solution is homemade, and its preparation method is as follows: 4,4'-diaminodiphenyl ether and pyromellitic dianhydride are added to N-methylpyrrolidone, and stirred at 10°C for 12 hours to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 400cp, wherein the molar ratio of pyromellitic dianhydride to 4,4'-diaminodiphenyl ether is 1:1;

[0047] The fifth polyamic acid solution is homemade, and its preparation method is as follows: 4,4'-diaminodiphenyl ether and pyromellitic dianhydride are added to N-methylpyrrolidone, and stirred at 15°C for 8 hours to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 800cp, wherein the molar ratio of pyromellitic dianhydride to 4,4'-diaminodiphenyl ether is 1:1;

[0048] The sixth polyamic acid solution was prepared in-house, and its preparation method was as follows: 4,4'-diaminodiphenyl ether and pyromellitic dianhydride were added to N-methylpyrrolidone, and stirred at 20°C for 3 hours to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 900 cp, wherein the molar ratio of pyromellitic dianhydride to 4,4'-diaminodiphenyl ether was 1:1;

[0049] The seventh polyamic acid solution is homemade, and its preparation method is as follows: 4,4'-diaminodiphenyl ether and pyromellitic dianhydride are added to N-methylpyrrolidone, and stirred for reaction at 25°C for 2 hours to obtain a polyamic acid solution with a solid content of 20% and a viscosity of 1000cp, wherein the molar ratio of pyromellitic dianhydride to 4,4'-diaminodiphenyl ether is 1:1.

[0050] Example 1

[0051] This embodiment provides a method for preparing a modified diamond abrasive, comprising the following steps:

[0052] Preparation of a first abrasive: adding tetraethyl orthosilicate to a 75% by volume ethanol solution, ultrasonicating for 10 minutes, then adding diamond abrasive with an average particle size of 50 nm, ultrasonicating for 15 minutes, and stirring at 80°C for 6 hours. The resulting product was washed three times with a 75% by volume ethanol solution and then dried at 50°C to obtain the first abrasive, wherein the mass ratio of tetraethyl orthosilicate to diamond abrasive was 1:1.25;

[0053] Preparation of a second abrasive: The first abrasive, the first polyamic acid solution, and N-ethylpyridinium tetrafluoroborate were ultrasonically mixed for 1 hour, and the resulting mixture was spray granulated using the following spray granulation parameters: drying temperature of 350° C., nozzle pressure of 2 MPa, and nozzle diameter of 0.05 mm, to obtain the second abrasive; wherein the mass ratio of the first abrasive to the first polyamic acid solution was 1:1.4, and the mass of the N-ethylpyridinium tetrafluoroborate was 4% of the mass of the first polyamic acid solution, based on the solid content of the first polyamic acid solution;

[0054] Preparation of modified diamond abrasive: The second abrasive was placed in an oven, heated to 90°C at a heating rate of 5°C / min under a nitrogen atmosphere, and kept warm for 30 min. The temperature was then increased to 250°C and kept warm for 10 min. Finally, the temperature was increased to 350°C and kept warm for 10 min. The modified diamond abrasive was naturally cooled to room temperature to obtain the modified diamond abrasive.

[0055] Example 2

[0056] This embodiment provides a method for preparing a modified diamond abrasive, comprising the following steps:

[0057] Preparation of a first abrasive: γ-methacryloxypropyltrimethoxysilane was added to a 75% by volume ethanol solution, and after ultrasonication for 20 minutes, diamond abrasive with an average particle size of 200 nm was added. After ultrasonication for 30 minutes, the solution was stirred at 50°C for 10 hours. The resulting product was washed three times with a 75% by volume ethanol solution and then dried at 50°C to obtain a first abrasive, wherein the mass ratio of γ-methacryloxypropyltrimethoxysilane to diamond abrasive was 1:1;

[0058] Preparation of a second abrasive: The first abrasive, the second polyamic acid solution, and 1-propyl-3-methylimidazolium chloride were ultrasonically mixed for 2 hours, and the resulting mixture was spray granulated using the following spray granulation parameters: drying temperature of 300° C., nozzle pressure of 2.2 MPa, and nozzle diameter of 0.08 mm to obtain the second abrasive; wherein the mass ratio of the first abrasive to the second polyamic acid solution was 1:1.5, and the mass of the 1-propyl-3-methylimidazolium chloride was 4% of the mass of the second polyamic acid solution, based on the solid content of the second polyamic acid solution;

[0059] Preparation of modified diamond abrasive: The second abrasive was placed in an oven, and heated to 120°C at a heating rate of 10°C / min under a nitrogen atmosphere for 45 min, then heated to 220°C for 30 min, and finally heated to 330°C for 30 min. The temperature was naturally cooled to room temperature to obtain the modified diamond abrasive.

[0060] Example 3

[0061] This embodiment provides a method for preparing a modified diamond abrasive, comprising the following steps:

[0062] Preparation of a first abrasive: γ-aminopropyltriethoxysilane was added to a 75% by volume ethanol solution, and after ultrasonication for 30 minutes, diamond abrasive with an average particle size of 50 nm was added. After ultrasonication for 60 minutes, the mixture was stirred at 50°C for 3 hours. The resulting product was washed three times with a 75% by volume ethanol solution and then dried at 50°C to obtain the first abrasive, wherein the mass ratio of γ-aminopropyltriethoxysilane to diamond abrasive was 1:1;

[0063] Preparation of a second abrasive: The first abrasive, the third polyamic acid solution, and N-ethylpyridinium tetrafluoroborate were ultrasonically mixed for 5 hours, and the resulting mixture was spray granulated using the following spray granulation parameters: drying temperature of 360° C., nozzle pressure of 2.5 MPa, and nozzle diameter of 0.05 mm to obtain the second abrasive; wherein the mass ratio of the first abrasive to the third polyamic acid solution was 1:1.2, and the mass of the N-ethylpyridinium tetrafluoroborate was 4% of the mass of the third polyamic acid solution, based on the solid content of the third polyamic acid solution;

[0064] Preparation of modified diamond abrasive: The second abrasive was placed in an oven, heated to 100°C at a heating rate of 8°C / min under a nitrogen atmosphere, and kept warm for 60 min, then heated to 280°C and kept warm for 20 min, and finally heated to 360°C and kept warm for 20 min. The mixture was naturally cooled to room temperature to obtain modified diamond abrasive.

[0065] Example 4

[0066] This embodiment provides a method for preparing a modified diamond abrasive, which differs from the preparation method of Example 1 only in that a fourth polyamic acid solution is used to replace the first polyamic acid solution.

[0067] Example 5

[0068] This embodiment provides a method for preparing a modified diamond abrasive, which differs from the preparation method of Example 1 only in that a fifth polyamic acid solution is used to replace the first polyamic acid solution.

[0069] Example 6

[0070] This embodiment provides a method for preparing a modified diamond abrasive, which differs from the preparation method of Example 1 only in that a sixth polyamic acid solution is used to replace the first polyamic acid solution.

[0071] Example 7

[0072] This embodiment provides a method for preparing a modified diamond abrasive, which differs from the preparation method of Example 1 only in that, based on the solid content of the first polyamic acid solution, the mass of N-ethylpyridinium tetrafluoroborate is 8% of the mass of the first polyamic acid solution.

[0073] Example 8

[0074] This embodiment provides a method for preparing a modified diamond abrasive, which differs from the preparation method of Example 1 only in that, based on the solid content of the first polyamic acid solution, the mass of N-ethylpyridinium tetrafluoroborate is 2% of the mass of the first polyamic acid solution.

[0075] Example 9

[0076] This embodiment provides a method for preparing a modified diamond abrasive, which differs from the preparation method of Example 1 only in that, based on the solid content of the first polyamic acid solution, the mass of N-ethylpyridinium tetrafluoroborate is 10% of the mass of the first polyamic acid solution.

[0077] Comparative Example 1

[0078] This comparative example provides a method for preparing a modified diamond abrasive, comprising the following steps:

[0079] Preparation of a first abrasive: A diamond abrasive having an average particle size of 50 nm, a first polyamic acid solution, and N-ethylpyridinium tetrafluoroborate were mixed by ultrasonication for 1 hour, and the resulting mixture was spray granulated using the following spray granulation parameters: a drying temperature of 350° C., a nozzle pressure of 2 MPa, and a nozzle diameter of 0.05 mm, to obtain the first abrasive; wherein the mass ratio of the diamond abrasive to the first polyamic acid solution was 1:1.4, and the mass of the N-ethylpyridinium tetrafluoroborate was 4% of the mass of the first polyamic acid solution, based on the solid content of the first polyamic acid solution;

[0080] Preparation of the second abrasive: placing the first abrasive in an oven, heating the oven at a heating rate of 5°C / min under a nitrogen atmosphere to 90°C for 30 min, then heating the oven to 250°C for 10 min, and finally heating the oven to 350°C for 10 min, and naturally cooling the oven to room temperature to obtain the second abrasive;

[0081] Preparation of modified diamond abrasive: Tetraethyl orthosilicate was added to a 75% by volume ethanol solution, ultrasonicated for 10 minutes, then a second abrasive was added, ultrasonicated for 15 minutes, and stirred at 80°C for 6 hours. The resulting product was washed three times with a 75% by volume ethanol solution and then dried at 50°C to obtain a modified diamond abrasive, wherein the mass ratio of tetraethyl orthosilicate to the second abrasive was 1:1.25.

[0082] Comparative Example 2

[0083] This comparative example provides a preparation method of a modified diamond abrasive, which differs from the preparation method of Example 1 only in that it does not contain ionic liquid, that is, the step of preparing the second abrasive is: mixing the first abrasive and the first polyamic acid solution with ultrasound for 1 hour, and spraying and granulating the obtained mixture. The parameters of the spray granulation are: drying temperature of 350°C, nozzle pressure of 2 MPa, and nozzle diameter of 0.05 mm to obtain the second abrasive; wherein the mass ratio of the first abrasive to the first polyamic acid solution is 1:1.4.

[0084] Comparative Example 3

[0085] This comparative example provides a method for preparing a modified diamond abrasive, which differs from the preparation method of Example 1 only in that the seventh polyamic acid solution is used to replace the first polyamic acid solution.

[0086] Comparative Example 4

[0087] This comparative example provides a method for preparing a modified diamond abrasive, which differs from the preparation method of Example 1 only in that, based on the solid content of the first polyamic acid solution, the mass of N-ethylpyridinium tetrafluoroborate is 1% of the mass of the first polyamic acid solution.

[0088] Performance Testing

[0089] (1) Using an infrared spectrometer to test the modified diamond abrasive of Example 1;

[0090] (2) Sphericity: The diamond abrasive of Example 1, the modified diamond abrasives of Examples 1-9, and the modified diamond abrasives of Comparative Examples 1-4 were tested using a scanning electron microscope (SEM), and the sphericity of the modified diamond abrasives was calculated using Formula I, where sphericity = volume of diamond abrasive / specific surface area of ​​diamond abrasive. According to Formula I, the closer the sphericity is to 1, the better the sphericity of the modified diamond abrasive.

[0091] (3) Mechanical strength: The strength of the abrasive is tested by pressing the abrasive particles under static charge, that is, 5g of abrasive sample is placed on the surface of a cylindrical disk, and then another cylindrical disk is placed on it, and then the pressure is applied to 30 kg / cm 2, sieve out the crushed part of the abrasive, and determine it by the ratio of the weight of the remaining uncrushed part to the total weight. The larger the ratio, the greater the strength of the abrasive, and vice versa, it means that the strength of the abrasive is small.

[0092] The test results are shown in Figure 1-3 and Table 1.

[0093] FIG1 is an infrared spectrum of the modified diamond abrasive of Example 1. As can be seen from FIG1 , 1370 cm -1 is the CN stretching vibration peak, 1500cm -1 The characteristic peak of benzene ring, 1720cm -1 and 1780cm -1 They are symmetrical imine C=O bond and asymmetrical imine C=O bond, and at 1550cm -1 and 1660cm -1 There is no amide peak nearby, indicating that the imidization reaction is almost complete.

[0094] FIG2 is an SEM image of the diamond abrasive of Example 1, and FIG3 is an SEM image of the modified diamond abrasive of Example 1. It can be seen from FIG2 and FIG3 that the modified diamond abrasive is a secondary particle formed by the accumulation of diamond abrasives, and the modified diamond abrasive is spherical.

[0095] Table 1

[0096] As can be seen from Table 1, the modified diamond abrasive prepared in the present disclosure has high sphericity and mechanical strength.

[0097] By comparing Example 1, Examples 4-6 and Comparative Example 3, it can be seen that when the viscosity of the polyamic acid solution is 400-800 cp, the sphericity and mechanical strength of the obtained modified diamond abrasive are higher.

[0098] By comparing Example 1, Examples 7-9 and Comparative Example 4, it can be seen that when the mass of the ionic liquid is 4-8% of the mass of the polyamic acid solution, the sphericity and mechanical strength of the obtained modified diamond abrasive are higher.

[0099] By comparing Example 1 with Comparative Example 1, it can be seen that the change in the modification sequence of the diamond abrasive will cause the sphericity and mechanical strength of the modified diamond abrasive to decrease.

[0100] Comparison of Example 1 and Comparative Example 2 shows that the absence of ionic liquid in the process of preparing the second abrasive will reduce the sphericity and mechanical strength of the modified diamond abrasive.

[0101] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present disclosure rather than to limit the scope of protection of the present disclosure. Although the present disclosure has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present disclosure may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present disclosure.

Claims

1. A method for preparing a modified diamond abrasive, characterized in that: The following steps are involved: Modifying the diamond abrasive by using a silane coupling agent to obtain a first abrasive; After uniformly mixing the first abrasive, the polyamic acid solution and the ionic liquid, spraying and granulating the mixture to obtain the second abrasive; The second abrasive is subjected to imidization treatment to obtain a modified diamond abrasive; The viscosity of the polyamic acid solution is 200-900 cp.

2. The preparation method according to claim 1, wherein The solid content of the polyamic acid solution is 10-30%. Based on the solid content of the polyamic acid solution, the mass of the ionic liquid is 2-10% of the mass of the polyamic acid solution.

3. The preparation method according to claim 1, wherein The mass ratio of the first abrasive to the polyamic acid solution is 1:1.2-1.5; and / or the mass ratio of the diamond abrasive to the silane coupling agent is 1:1-1.

3.

4. The preparation method according to claim 1, wherein The imidization treatment steps are: under the protection of inert gas, keeping the second abrasive at a temperature of 90-120° C. for 30-60 minutes, then keeping it at a temperature of 220-280° C. for 10-30 minutes, and finally keeping it at a temperature of 330-360° C. for 10-30 minutes.

5. The preparation method according to claim 1, wherein The polyamic acid solution is obtained by a solution polymerization reaction of a dianhydride monomer and a diamine monomer in an organic solvent, wherein the dianhydride monomer is at least one of pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride and perylenetetracarboxylic dianhydride; the diamine monomer is at least one of 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether and 1,4-phenylenediamine; and the organic solvent is at least one of N,N-dimethylacetamide and N-methylpyrrolidone.

6. The preparation method according to claim 1, wherein The ionic liquid is an imidazole ionic liquid and / or a pyridine ionic liquid.

7. The preparation method according to claim 1, wherein The silane coupling agent is at least one of ethyl orthosilicate, γ-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane.

8. The preparation method according to claim 1, wherein The parameters of the spray granulation are: drying temperature of 300-400° C., nozzle pressure of 2-2.5 MPa, and nozzle diameter of 0.05-0.08 mm.

9. A modified diamond abrasive, characterized in that: The modified diamond abrasive is prepared by the preparation method of any one of claims 1 to 8.

10. Use of the modified diamond abrasive according to claim 9 in preparing abrasive tools.

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