High-hardness silicon carbide grinding powder and processing technology thereof

Abstract

The invention discloses high-hardness silicon carbide grinding powder and a processing technology thereof, and relates to the technical field of silicon carbide grinding powder.The processing technology comprises the steps that surface passivated silicon carbide micro powder, gamma-glycidyl ether oxypropyl triethoxy silane and gamma-aminopropyl triethoxy silane are added into absolute ethyl alcohol, argon is introduced, and a silicon carbide intermediate is obtained; adding lauryl methacrylate, perfluorooctyl acrylate, sodium persulfate and ferrous sulfate into the silicon carbide intermediate, pickling to remove impurities, washing with ultrapure water, and drying to obtain modified silicon carbide micro powder; the treated silicon carbide micro powder is high in electrification property, particle aggregation is inhibited through the electrostatic-space synergistic effect, and the dispersity and fluidity of a silicon carbide system are remarkably improved. Carrying out wet grading on the modified silicon carbide micro powder to obtain silicon carbide ultrafine powder; and taking the silicon carbide ultrafine powder, adding polyethylene glycol, introducing argon, and carrying out hot pressing to obtain the high-hardness silicon carbide grinding powder.

Description

Technical Field

[0001] This invention relates to the field of silicon carbide grinding powder technology, specifically a high-hardness silicon carbide grinding powder and its processing technology. Background Technology

[0002] Silicon carbide abrasive powder is a granular material. Silicon carbide has high hardness, wear resistance and chemical stability, and is commonly used as an abrasive and reinforcing material. It has a wide range of applications in ceramics, semiconductors, photovoltaics and other fields.

[0003] Silicon carbide has a Mohs hardness of 9.2, which is only 0.8 different from diamond, the hardest known substance in nature. It is extremely hard and is an ideal abrasive material. Secondly, silicon carbide has good wear resistance and can adapt to various high-wear environments. Furthermore, the chemical stability of silicon carbide allows it to adapt to various complex processing environments and does not easily contaminate the processed materials.

[0004] To further improve the hardness of silicon carbide and optimize the production process of silicon carbide grinding powder, this invention provides a high-hardness silicon carbide grinding powder and its processing technology. Summary of the Invention

[0005] The purpose of this invention is to provide a high-hardness silicon carbide grinding powder and its processing technology to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] Step 1: Argon gas is introduced, and surface passivated silicon carbide micro powder, γ-glycidyl etheroxypropyltriethoxysilane, and γ-aminopropyltriethoxysilane are added to anhydrous ethanol to obtain silicon carbide intermediate;

[0008] Step 2: Add lauryl methacrylate, perfluorooctyl acrylate, sodium persulfate, and ferrous sulfate to the silicon carbide intermediate, acid wash to remove impurities, wash with ultrapure water, and dry to obtain modified silicon carbide micro powder.

[0009] Step 3: The modified silicon carbide micro powder is subjected to wet classification to obtain silicon carbide ultrafine powder;

[0010] Step 4: Take silicon carbide ultrafine powder, add polyethylene glycol, pass argon gas through, and hot press to obtain high-hardness silicon carbide grinding powder.

[0011] A more optimized method for preparing surface passivated silicon carbide micro powder is as follows: take silicon carbide micro powder and deposit it for 2-4 hours under the conditions of temperature 1040-1060℃, microwave power 550-650W, and pulse bias voltage 45-55V to obtain surface passivated silicon carbide micro powder.

[0012] The optimized modified silicon carbide micro powder includes the following components, in parts by weight: 0.05-0.15 parts by weight of lauryl methacrylate, 0.04-0.06 parts by weight of perfluorooctyl acrylate, 0.005-0.015 parts by weight of sodium persulfate, and 0.005-0.015 parts by weight of ferrous sulfate.

[0013] A more optimized method for preparing silicon carbide micro powder is as follows: add nano-silicon carbide and modified silica sol to silicon carbide coarse powder, adjust the pH value to 8-10, ball mill for 39-41 hours, and dry to obtain silicon carbide micro powder.

[0014] A more optimized method for preparing modified silica sol is as follows: γ-aminopropyltriethoxysilane is added to silica sol and reacted at a temperature of 50-60℃ for 5-7 hours to obtain modified silica sol.

[0015] A more optimized method for preparing coarse silicon carbide powder is as follows: mix the dried powder with the sintering aid powder, grind it initially, introduce argon gas, heat it, remove impurities, and obtain coarse silicon carbide powder.

[0016] A more optimized method for preparing the dried powder is as follows: weigh sodium carbonate and iron oxide, mix them evenly to prepare a composite catalyst; weigh glucose and sodium silicate, add them to the composite catalyst, stir evenly, and dry under vacuum conditions at a temperature of 105-115℃ for 45-50 hours to obtain the dried powder.

[0017] A more optimized method for preparing the sintering aid powder is as follows: add nano-cerium oxide, methylglycine diacetic acid, ammonium hydrogen fluoride, and ammonium fluoroaluminate to the modified silica sol, mix evenly, freeze-dry, and grind to obtain the sintering aid powder.

[0018] A more optimized sintering aid powder includes the following components, listed in parts by weight: 0.1-0.3 parts by weight of nano-cerium oxide, 0.005-0.015 parts by weight of methylglycine diacetic acid, 0.05-0.15 parts by weight of ammonium bifluoride, 0.05-0.15 parts by weight of ammonium fluoroaluminate, and 1-3 parts by weight of modified silica sol.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. A solution-sol method is used to prepare the sintering aid powder. Modified silica sol serves as a dispersion system to accommodate other reactants, promoting uniform component distribution. Nano-cerium oxide, with its high specific surface area, fills the pores in the silicon carbide synthesis process, reducing pore formation and thus improving material density. Furthermore, the reversible redox properties of cerium ions and the presence of numerous oxygen vacancies on the surface promote atomic diffusion, significantly increasing the chemical reaction rate and enhancing material density and mechanical strength. Methylglycine diacetic acid forms a metal chelate with cerium ions through coordination, reducing intermolecular electrostatic repulsion and further maintaining system stability. Ammonium bifluoride and ammonium fluoroaluminate decompose at high temperatures, lowering the sintering temperature.

[0021] 2. High-temperature and high-pressure ball milling shaping method is adopted, and nano-silicon carbide is added as a grinding aid. It has high hardness and can participate in the physical grinding process as an abrasive to improve ball milling efficiency. Secondly, the high specific surface area of ​​nano-silicon carbide can prevent the coarse silicon carbide powder from agglomerating during the ball milling process. Modified silica sol is used as a dispersant to make the coarse silicon carbide powder evenly dispersed during the ball milling process, thereby improving the ball milling efficiency and flowability of the material.

[0022] 3. By using microwave plasma chemical vapor deposition technology, a diamond-like film is generated on the substrate surface to improve the hardness and mechanical strength of the substrate.

[0023] 4. The alkoxy groups in γ-glycidoxypropyltriethoxysilane and γ-aminopropyltriethoxysilane can form chemical bonds with the hydroxyl groups on the surface of silicon carbide micropowder, forming a silane coupling agent intermediate layer on the surface of silicon carbide micropowder. Then, using lauryl methacrylate and perfluorooctyl acrylate as acrylic acid graft polymerization monomers, sodium persulfate as an initiator, and ferrous sulfate as a reducing agent, the acrylic acid graft polymerization monomers are grafted onto the silane coupling agent intermediate layer to form an organic polymer coating layer. The treated silicon carbide micropowder has strong charge and inhibits particle aggregation through electrostatic-spatial synergistic effect, significantly improving the dispersibility and flowability of the silicon carbide system.

[0024] 5. Using hot isostatic pressing technology and adding polyethylene glycol as a dispersant, the internal pores of silicon carbide particles are closed, atomic diffusion and grain rearrangement are promoted to improve the density of the structure and form a uniform and dense stable structure. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The sources and types of substances involved in this invention are not particularly limited, and exemplary examples include:

[0027] The silica sol, with product number JN-830A, is provided by Foshan Nanhai Kening Chemical Co., Ltd.; the nano-cerium oxide, with product number JD1227143709, is provided by Shanghai Jiadeer Chemical Technology Co., Ltd.; the nano-silicon carbide, with product number YM-SiC-100N, is provided by Yumu (Ningbo) New Materials Co., Ltd.; and the polyethylene glycol, with product number 25322-68-3, is provided by Shandong Xinheng Chemical Co., Ltd.

[0028] Example 1: A processing technology for high-hardness silicon carbide grinding powder;

[0029] Step 1: Preparation of coarse silicon carbide powder

[0030] S1: Weigh 1g of sodium carbonate and 3.2g of iron oxide, mix them evenly, and prepare a composite catalyst; weigh 10g of glucose and 40g of sodium silicate, add 4.2g of the composite catalyst, stir evenly, and dry under vacuum at 105℃ for 45h to obtain a dry powder.

[0031] S2: Add 1g of γ-aminopropyltriethoxysilane to 10g of silica sol and react at 50℃ for 5h to obtain modified silica sol;

[0032] S3: Add 0.1g of nano-cerium oxide, 0.005g of methylglycine diacetic acid, 0.05g of ammonium hydrogen fluoride, and 0.05g of ammonium fluoroaluminate to 1g of modified silica sol, mix evenly, freeze dry, and grind to obtain sintering aid powder;

[0033] S4: Mix the dry powder with the calcination aid powder, grind it initially, introduce argon gas, heat it to 800℃ at a heating rate of 6℃ / min; then heat it to 1300℃ and maintain the temperature for 2 hours to remove impurities and obtain coarse silicon carbide powder.

[0034] Step 2: Preparation of silicon carbide micro powder

[0035] 1g of nano-silicon carbide and 0.3g of the modified silica sol obtained above were added to 50g of coarse silicon carbide powder, the pH value was adjusted to 8, and the mixture was ball-milled for 39h at a speed of 200r / min and then dried to obtain silicon carbide micro powder.

[0036] Step 3: Preparation of silicon carbide ultrafine powder

[0037] S1: Take the silicon carbide micro powder obtained above and deposit it for 2 hours under the conditions of temperature 1040℃, microwave power 550W, pulse bias voltage 45V. Control the gas flow rate ratio of hydrogen:trimethylsilane = 500:5 to obtain surface passivated silicon carbide micro powder.

[0038] S2: Argon gas is introduced, and 50g of surface passivated silicon carbide micro powder, 1.5g of γ-glycidyl etheroxypropyltriethoxysilane and 1.5g of γ-aminopropyltriethoxysilane are added to 350mL of anhydrous ethanol. The reaction is carried out at a reaction temperature of 35℃ for 5h to obtain silicon carbide intermediate.

[0039] S3: Add 0.05g lauryl methacrylate, 0.04g perfluorooctyl acrylate, 0.005g sodium persulfate, and 0.005g ferrous sulfate to the silicon carbide intermediate obtained above, adjust the pH to 5, the reaction temperature to 75℃, and the reaction time to 5h; acid wash to remove impurities, wash with ultrapure water, and dry to obtain modified silicon carbide micro powder.

[0040] S4: The modified silicon carbide micro powder obtained above is subjected to wet classification to obtain silicon carbide ultrafine powder with a particle size D50 of 50-1000nm.

[0041] Step 4: Preparation of high-hardness silicon carbide grinding powder

[0042] Take 50g of the silicon carbide ultrafine powder obtained above, add 0.3g of polyethylene glycol 400, introduce argon gas, maintain the temperature at 1300℃ and the pressure at 150MPa, and hot press for 3h to obtain high-hardness silicon carbide grinding powder.

[0043] Example 2: A processing technology for high-hardness silicon carbide grinding powder;

[0044] Step 1: Preparation of coarse silicon carbide powder

[0045] S1: Weigh 1g of sodium carbonate and 3.2g of iron oxide, mix them evenly, and prepare a composite catalyst; weigh 10g of glucose and 40g of sodium silicate, add 4.2g of the composite catalyst, stir evenly, and dry under vacuum at 110℃ for 48h to obtain a dry powder.

[0046] S2: Add 1g of γ-aminopropyltriethoxysilane to 10g of silica sol and react at 55℃ for 6h to obtain modified silica sol;

[0047] S3: Add 0.2g of nano-cerium oxide, 0.01g of methylglycine diacetic acid, 0.1g of ammonium hydrogen fluoride, and 0.1g of ammonium fluoroaluminate to 2g of modified silica sol, mix evenly, freeze dry, and grind to obtain sintering aid powder;

[0048] S4: Mix the dry powder with the calcination aid powder, grind it initially, introduce argon gas, heat it to 800℃ at a heating rate of 6℃ / min; then heat it to 1300℃ and maintain the temperature for 2 hours to remove impurities and obtain coarse silicon carbide powder.

[0049] Step 2: Preparation of silicon carbide micro powder

[0050] 1g of nano-silicon carbide and 0.3g of the modified silica sol obtained above were added to 50g of coarse silicon carbide powder, the pH value was adjusted to 9, and the mixture was ball-milled for 40h at a speed of 200r / min and dried to obtain silicon carbide micro powder.

[0051] Step 3: Preparation of silicon carbide ultrafine powder

[0052] S1: Take the silicon carbide micro powder obtained above and deposit it for 3 hours under the conditions of temperature 1050℃, microwave power 600W, pulse bias voltage 50V. Control the gas flow rate ratio of hydrogen:trimethylsilane = 500:5 to obtain surface passivated silicon carbide micro powder.

[0053] S2: Argon gas is introduced, and 50g of surface passivated silicon carbide micro powder, 1.5g of γ-glycidyl etheroxypropyltriethoxysilane and 1.5g of γ-aminopropyltriethoxysilane are added to 350mL of anhydrous ethanol. The reaction is carried out at a reaction temperature of 40℃ for 6h to obtain silicon carbide intermediate.

[0054] S3: Add 0.1g lauryl methacrylate, 0.05g perfluorooctyl acrylate, 0.01g sodium persulfate, and 0.01g ferrous sulfate to the silicon carbide intermediate obtained above, adjust the pH to 6, the reaction temperature to 80℃, and the reaction time to 6h; acid wash to remove impurities, wash with ultrapure water, and dry to obtain modified silicon carbide micro powder.

[0055] S4: The modified silicon carbide micro powder obtained above is subjected to wet classification to obtain silicon carbide ultrafine powder with a particle size D50 of 50-1000nm.

[0056] Step 4: Preparation of high-hardness silicon carbide grinding powder

[0057] Take 50g of the silicon carbide ultrafine powder obtained above, add 0.3g of polyethylene glycol 400, introduce argon gas, maintain the temperature at 1300℃ and the pressure at 150MPa, and hot press for 4h to obtain high-hardness silicon carbide grinding powder.

[0058] Example 3: A processing technology for high-hardness silicon carbide grinding powder;

[0059] Step 1: Preparation of coarse silicon carbide powder

[0060] S1: Weigh 1g of sodium carbonate and 3.2g of iron oxide, mix them evenly, and prepare a composite catalyst; weigh 10g of glucose and 40g of sodium silicate, add 4.2g of the composite catalyst, stir evenly, and dry under vacuum at 115℃ for 50h to obtain a dry powder.

[0061] S2: Add 1g of γ-aminopropyltriethoxysilane to 10g of silica sol and react at 60℃ for 7h to obtain modified silica sol;

[0062] S3: Add 0.3g of nano-cerium oxide, 0.015g of methylglycine diacetic acid, 0.15g of ammonium hydrogen fluoride, and 0.15g of ammonium fluoroaluminate to 3g of modified silica sol, mix evenly, freeze dry, and grind to obtain sintering aid powder;

[0063] S4: Mix the dry powder with the calcination aid powder, grind it initially, introduce argon gas, heat it to 800℃ at a heating rate of 6℃ / min; then heat it to 1300℃ and maintain the temperature for 2 hours to remove impurities and obtain coarse silicon carbide powder.

[0064] Step 2: Preparation of silicon carbide micro powder

[0065] 1g of nano-silicon carbide and 0.3g of the modified silica sol obtained above were added to 50g of coarse silicon carbide powder, the pH value was adjusted to 10, and the mixture was ball-milled for 41h at a speed of 200r / min and then dried to obtain silicon carbide micro powder.

[0066] Step 3: Preparation of silicon carbide ultrafine powder

[0067] S1: Take the silicon carbide micro powder obtained above and deposit it for 4 hours under the conditions of temperature 1060℃, microwave power 650W, pulse bias voltage 55V. Control the gas flow rate ratio of hydrogen:trimethylsilane = 500:5 to obtain surface passivated silicon carbide micro powder.

[0068] S2: Argon gas is introduced, and 50g of surface passivated silicon carbide micro powder, 1.5g of γ-glycidyl etheroxypropyltriethoxysilane and 1.5g of γ-aminopropyltriethoxysilane are added to 350mL of anhydrous ethanol. The reaction is carried out at a reaction temperature of 45℃ for 7h to obtain silicon carbide intermediate.

[0069] S3: Add 0.15g lauryl methacrylate, 0.06g perfluorooctyl acrylate, 0.015g sodium persulfate, and 0.015g ferrous sulfate to the silicon carbide intermediate obtained above, adjust the pH to 7, the reaction temperature to 85℃, and the reaction time to 7h; acid wash to remove impurities, wash with ultrapure water, and dry to obtain modified silicon carbide micro powder.

[0070] S4: The modified silicon carbide micro powder obtained above is subjected to wet classification to obtain silicon carbide ultrafine powder with a particle size D50 of 50-1000nm.

[0071] Step 4: Preparation of high-hardness silicon carbide grinding powder

[0072] Take 50g of the silicon carbide ultrafine powder obtained above, add 0.3g of polyethylene glycol 400, introduce argon gas, maintain the temperature at 1300℃ and the pressure at 150MPa, and hot press for 5h to obtain high-hardness silicon carbide grinding powder.

[0073] Comparative Example 1: No calcination aid powder was added; all other procedures were the same as in Example 2. The specific operations are as follows:

[0074] Step 1: Preparation of coarse silicon carbide powder

[0075] S1: Weigh 1g of sodium carbonate and 3.2g of iron oxide, mix them evenly, and prepare a composite catalyst; weigh 10g of glucose and 40g of sodium silicate, add 4.2g of the composite catalyst, stir evenly, and dry under vacuum at 110℃ for 48h to obtain a dry powder.

[0076] S2: The dry powder is initially ground, argon gas is introduced, and the temperature is raised to 800℃ at a rate of 6℃ / min; then the temperature is raised to 1300℃ and maintained at a constant temperature for 2 hours to remove impurities and obtain coarse silicon carbide powder.

[0077] Step 2: Preparation of silicon carbide micro powder

[0078] S1: Add 1g of γ-aminopropyltriethoxysilane to 10g of silica sol and react at 55℃ for 6h to obtain modified silica sol;

[0079] S2: Add 1g of nano-silicon carbide and 0.3g of the modified silica sol obtained above to 50g of coarse silicon carbide powder, adjust the pH value to 9, ball mill at 200r / min for 40h, and dry to obtain silicon carbide micro powder.

[0080] Step 3: Preparation of silicon carbide ultrafine powder

[0081] S1: Take the silicon carbide micro powder obtained above and deposit it for 3 hours under the conditions of temperature 1050℃, microwave power 600W, pulse bias voltage 50V. Control the gas flow rate ratio of hydrogen:trimethylsilane = 500:5 to obtain surface passivated silicon carbide micro powder.

[0082] S2: Argon gas is introduced, and 50g of surface passivated silicon carbide micro powder, 1.5g of γ-glycidyl etheroxypropyltriethoxysilane and 1.5g of γ-aminopropyltriethoxysilane are added to 350mL of anhydrous ethanol. The reaction is carried out at a reaction temperature of 40℃ for 6h to obtain silicon carbide intermediate.

[0083] S3: Add 0.1g lauryl methacrylate, 0.05g perfluorooctyl acrylate, 0.01g sodium persulfate, and 0.01g ferrous sulfate to the silicon carbide intermediate obtained above, adjust the pH to 6, the reaction temperature to 80℃, and the reaction time to 6h; acid wash to remove impurities, wash with ultrapure water, and dry to obtain modified silicon carbide micro powder.

[0084] S4: The modified silicon carbide micro powder obtained above is subjected to wet classification to obtain silicon carbide ultrafine powder with a particle size D50 of 50-1000nm.

[0085] Step 4: Preparation of high-hardness silicon carbide grinding powder

[0086] Take 50g of the silicon carbide ultrafine powder obtained above, add 0.3g of polyethylene glycol 400, introduce argon gas, maintain the temperature at 1300℃ and the pressure at 150MPa, and hot press for 4h to obtain high-hardness silicon carbide grinding powder.

[0087] Comparative Example 2: No nano-silicon carbide was added; all other procedures were the same as in Example 2, and the specific operations were as follows:

[0088] Step 1: Preparation of coarse silicon carbide powder

[0089] S1: Weigh 1g of sodium carbonate and 3.2g of iron oxide, mix them evenly, and prepare a composite catalyst; weigh 10g of glucose and 40g of sodium silicate, add 4.2g of the composite catalyst, stir evenly, and dry under vacuum at 110℃ for 48h to obtain a dry powder.

[0090] S2: Add 1g of γ-aminopropyltriethoxysilane to 10g of silica sol and react at 55℃ for 6h to obtain modified silica sol;

[0091] S3: Add 0.2g of nano-cerium oxide, 0.01g of methylglycine diacetic acid, 0.1g of ammonium hydrogen fluoride, and 0.1g of ammonium fluoroaluminate to 2g of modified silica sol, mix evenly, freeze dry, and grind to obtain sintering aid powder;

[0092] S4: Mix the dry powder with the calcination aid powder, grind it initially, introduce argon gas, heat it to 800℃ at a heating rate of 6℃ / min; then heat it to 1300℃ and maintain the temperature for 2 hours to remove impurities and obtain coarse silicon carbide powder.

[0093] Step 2: Preparation of silicon carbide micro powder

[0094] Add 0.3g of the modified silica sol obtained above to 50g of coarse silicon carbide powder, adjust the pH value to 9, ball mill for 40h at a speed of 200r / min, and dry to obtain silicon carbide micro powder.

[0095] Step 3: Preparation of silicon carbide ultrafine powder

[0096] S1: Take the silicon carbide micro powder obtained above and deposit it for 3 hours under the conditions of temperature 1050℃, microwave power 600W, pulse bias voltage 50V. Control the gas flow rate ratio of hydrogen:trimethylsilane = 500:5 to obtain surface passivated silicon carbide micro powder.

[0097] S2: Argon gas is introduced, and 50g of surface passivated silicon carbide micro powder, 1.5g of γ-glycidyl etheroxypropyltriethoxysilane and 1.5g of γ-aminopropyltriethoxysilane are added to 350mL of anhydrous ethanol. The reaction is carried out at a reaction temperature of 40℃ for 6h to obtain silicon carbide intermediate.

[0098] S3: Add 0.1g lauryl methacrylate, 0.05g perfluorooctyl acrylate, 0.01g sodium persulfate, and 0.01g ferrous sulfate to the silicon carbide intermediate obtained above, adjust the pH to 6, the reaction temperature to 80℃, and the reaction time to 6h; acid wash to remove impurities, wash with ultrapure water, and dry to obtain modified silicon carbide micro powder.

[0099] S4: The modified silicon carbide micro powder obtained above is subjected to wet classification to obtain silicon carbide ultrafine powder with a particle size D50 of 50-1000nm.

[0100] Step 4: Preparation of high-hardness silicon carbide grinding powder

[0101] Take 50g of the silicon carbide ultrafine powder obtained above, add 0.3g of polyethylene glycol 400, introduce argon gas, maintain the temperature at 1300℃ and the pressure at 150MPa, and hot press for 4h to obtain high-hardness silicon carbide grinding powder.

[0102] Comparative Example 3: Silicon carbide micropowder was not passivated using microwave plasma chemical vapor deposition technology; all other procedures were the same as in Example 2, with the specific operations as follows:

[0103] Step 1: Preparation of coarse silicon carbide powder

[0104] S1: Weigh 1g of sodium carbonate and 3.2g of iron oxide, mix them evenly, and prepare a composite catalyst; weigh 10g of glucose and 40g of sodium silicate, add 4.2g of the composite catalyst, stir evenly, and dry under vacuum at 110℃ for 48h to obtain a dry powder.

[0105] S2: Add 1g of γ-aminopropyltriethoxysilane to 10g of silica sol and react at 55℃ for 6h to obtain modified silica sol;

[0106] S3: Add 0.2g of nano-cerium oxide, 0.01g of methylglycine diacetic acid, 0.1g of ammonium hydrogen fluoride, and 0.1g of ammonium fluoroaluminate to 2g of modified silica sol, mix evenly, freeze dry, and grind to obtain sintering aid powder;

[0107] S4: Mix the dry powder with the calcination aid powder, grind it initially, introduce argon gas, heat it to 800℃ at a heating rate of 6℃ / min; then heat it to 1300℃ and maintain the temperature for 2 hours to remove impurities and obtain coarse silicon carbide powder.

[0108] Step 2: Preparation of silicon carbide micro powder

[0109] 1g of nano-silicon carbide and 0.3g of the modified silica sol obtained above were added to 50g of coarse silicon carbide powder, the pH value was adjusted to 9, and the mixture was ball-milled for 40h at a speed of 200r / min and dried to obtain silicon carbide micro powder.

[0110] Step 3: Preparation of silicon carbide ultrafine powder

[0111] S1: Argon gas is introduced, and 50g of silicon carbide micro powder, 1.5g of γ-glycidyl etheroxypropyltriethoxysilane and 1.5g of γ-aminopropyltriethoxysilane are added to 350mL of anhydrous ethanol. The reaction is carried out at a reaction temperature of 40℃ for 6h to obtain silicon carbide intermediate.

[0112] S2: Add 0.1g lauryl methacrylate, 0.05g perfluorooctyl acrylate, 0.01g sodium persulfate, and 0.01g ferrous sulfate to the silicon carbide intermediate obtained above, adjust the pH to 6, react at 80℃ for 6h; acid wash to remove impurities, wash with ultrapure water, and dry to obtain modified silicon carbide micro powder.

[0113] S3: The modified silicon carbide micro powder obtained above is subjected to wet classification to obtain silicon carbide ultrafine powder with a particle size D50 of 50-1000nm.

[0114] Step 4: Preparation of high-hardness silicon carbide grinding powder

[0115] Take 50g of the silicon carbide ultrafine powder obtained above, add 0.3g of polyethylene glycol 400, introduce argon gas, maintain the temperature at 1300℃ and the pressure at 150MPa, and hot press for 4h to obtain high-hardness silicon carbide grinding powder.

[0116] Comparative Example 4: Without the addition of γ-glycidoxypropyltriethoxysilane and γ-aminopropyltriethoxysilane, the procedure was the same as in Example 2, and the specific steps are as follows:

[0117] Step 1: Preparation of coarse silicon carbide powder

[0118] S1: Weigh 1g of sodium carbonate and 3.2g of iron oxide, mix them evenly, and prepare a composite catalyst; weigh 10g of glucose and 40g of sodium silicate, add 4.2g of the composite catalyst, stir evenly, and dry under vacuum at 110℃ for 48h to obtain a dry powder.

[0119] S2: Add 1g of γ-aminopropyltriethoxysilane to 10g of silica sol and react at 55℃ for 6h to obtain modified silica sol;

[0120] S3: Add 0.2g of nano-cerium oxide, 0.01g of methylglycine diacetic acid, 0.1g of ammonium hydrogen fluoride, and 0.1g of ammonium fluoroaluminate to 2g of modified silica sol, mix evenly, freeze dry, and grind to obtain sintering aid powder;

[0121] S4: Mix the dry powder with the calcination aid powder, grind it initially, introduce argon gas, heat it to 800℃ at a heating rate of 6℃ / min; then heat it to 1300℃ and maintain the temperature for 2 hours to remove impurities and obtain coarse silicon carbide powder.

[0122] Step 2: Preparation of silicon carbide micro powder

[0123] 1g of nano-silicon carbide and 0.3g of the modified silica sol obtained above were added to 50g of coarse silicon carbide powder, the pH value was adjusted to 9, and the mixture was ball-milled for 40h at a speed of 200r / min and dried to obtain silicon carbide micro powder.

[0124] Step 3: Preparation of silicon carbide ultrafine powder

[0125] S1: Take the silicon carbide micro powder obtained above and deposit it for 3 hours under the conditions of temperature 1050℃, microwave power 600W, pulse bias voltage 50V. Control the gas flow rate ratio of hydrogen:trimethylsilane = 500:5 to obtain surface passivated silicon carbide micro powder.

[0126] S2: Argon gas is introduced, and 50g of surface passivated silicon carbide micro powder is added to 350mL of anhydrous ethanol. The reaction is carried out at a reaction temperature of 40℃ for 6h to obtain silicon carbide intermediate.

[0127] S3: Add 0.1g lauryl methacrylate, 0.05g perfluorooctyl acrylate, 0.01g sodium persulfate, and 0.01g ferrous sulfate to the silicon carbide intermediate obtained above, adjust the pH to 6, the reaction temperature to 80℃, and the reaction time to 6h; acid wash to remove impurities, wash with ultrapure water, and dry to obtain modified silicon carbide micro powder.

[0128] S4: The modified silicon carbide micro powder obtained above is subjected to wet classification to obtain silicon carbide ultrafine powder with a particle size D50 of 50-1000nm.

[0129] Step 4: Preparation of high-hardness silicon carbide grinding powder

[0130] Take 50g of the silicon carbide ultrafine powder obtained above, add 0.3g of polyethylene glycol 400, introduce argon gas, maintain the temperature at 1300℃ and the pressure at 150MPa, and hot press for 4h to obtain high-hardness silicon carbide grinding powder.

[0131] Comparative Example 5: Silicon carbide ultrafine powder was not treated with hot isostatic pressing (HIP). All other procedures were the same as in Example 2, and the specific operations are as follows:

[0132] Step 1: Preparation of coarse silicon carbide powder

[0133] S1: Weigh 1g of sodium carbonate and 3.2g of iron oxide, mix them evenly, and prepare a composite catalyst; weigh 10g of glucose and 40g of sodium silicate, add 4.2g of the composite catalyst, stir evenly, and dry under vacuum at 110℃ for 48h to obtain a dry powder.

[0134] S2: Add 1g of γ-aminopropyltriethoxysilane to 10g of silica sol and react at 55℃ for 6h to obtain modified silica sol;

[0135] S3: Add 0.2g of nano-cerium oxide, 0.01g of methylglycine diacetic acid, 0.1g of ammonium hydrogen fluoride, and 0.1g of ammonium fluoroaluminate to 2g of modified silica sol, mix evenly, freeze dry, and grind to obtain sintering aid powder;

[0136] S4: Mix the dry powder with the calcination aid powder, grind it initially, introduce argon gas, heat it to 800℃ at a heating rate of 6℃ / min; then heat it to 1300℃ and maintain the temperature for 2 hours to remove impurities and obtain coarse silicon carbide powder.

[0137] Step 2: Preparation of silicon carbide micro powder

[0138] 1g of nano-silicon carbide and 0.3g of the modified silica sol obtained above were added to 50g of coarse silicon carbide powder, the pH value was adjusted to 9, and the mixture was ball-milled for 40h at a speed of 200r / min and dried to obtain silicon carbide micro powder.

[0139] Step 3: Preparation of silicon carbide ultrafine powder

[0140] S1: Take the silicon carbide micro powder obtained above and deposit it for 3 hours under the conditions of temperature 1050℃, microwave power 600W, pulse bias voltage 50V. Control the gas flow rate ratio of hydrogen:trimethylsilane = 500:5 to obtain surface passivated silicon carbide micro powder.

[0141] S2: Argon gas is introduced, and 50g of surface passivated silicon carbide micro powder, 1.5g of γ-glycidyl etheroxypropyltriethoxysilane and 1.5g of γ-aminopropyltriethoxysilane are added to 350mL of anhydrous ethanol. The reaction is carried out at a reaction temperature of 40℃ for 6h to obtain silicon carbide intermediate.

[0142] S3: Add 0.1g lauryl methacrylate, 0.05g perfluorooctyl acrylate, 0.01g sodium persulfate, and 0.01g ferrous sulfate to the silicon carbide intermediate obtained above, adjust the pH to 6, the reaction temperature to 80℃, and the reaction time to 6h; acid wash to remove impurities, wash with ultrapure water, and dry to obtain modified silicon carbide micro powder.

[0143] S4: The modified silicon carbide micro powder obtained above is subjected to wet classification to obtain high-hardness silicon carbide grinding powder with a particle size D50 of 50-1000nm.

[0144] experiment:

[0145] The performance of silicon carbide grinding powders prepared in Examples 1-3 and Comparative Examples 1-5 was measured.

[0146] The experiment was conducted according to GB / T23538-2023 "Method for Determining the Toughness of Ordinary Abrasives in Ball Milling", with a sample mass of 15g. The Mohs hardness of the silicon carbide grinding powder was tested using the Mohs hardness test method, with a sample mass of 1g. The flowability of the silicon carbide grinding powder was tested using the Karl von Schüco method, with a test cylinder volume of 10mL and a sample mass of 5g. The data obtained from the above experiments are shown in Table 1 below.

[0147] Table 1

[0148] Ball milling toughness % Mohs hardness Compression % Example 1 83 9.7 12.9 Example 2 85 9.8 13 Example 3 84 9.7 12.8 Comparative Example 1 65 8.7 19 Comparative Example 2 73 8.9 20 Comparative Example 3 66 8.8 16 Comparative Example 4 77 9.1 21 Comparative Example 5 67 8.7 15

[0149] Conclusion: Based on the analysis of the above experimental data, the silicon carbide grinding powder prepared in Examples 1-3 of this invention has high hardness and good flowability, which enhances cutting force and improves grinding efficiency; while the silicon carbide grinding powder prepared in Comparative Examples 1-5 has significantly reduced hardness and flowability, and poor grinding efficiency.

[0150] Comparative analysis of Comparative Example 1 (without sintering aid powder) and Example 2 shows that the nano-cerium oxide in the sintering aid powder has a high specific surface area, which fills the pores of the material during the synthesis of silicon carbide, reducing the formation of pores and thus improving the density of the material. Secondly, since the cerium ions of cerium oxide have reversible redox properties and there are a large number of oxygen vacancies on the surface as active sites, it promotes atomic diffusion and significantly improves the chemical reaction rate. The modified silica sol, as a dispersion system, accommodates other reactants and promotes the uniformity of component distribution. Ammonium bifluoride and ammonium fluoroaluminate decompose at high temperatures, lowering the sintering temperature and making the reaction more complete. It also improves the hardness and flowability of silicon carbide grinding powder.

[0151] Comparative analysis of Comparative Example 2 (without nano-silicon carbide) and Example 2 shows that nano-silicon carbide has high hardness and can be used as an abrasive in the physical grinding process to improve ball milling efficiency. Secondly, nano-silicon carbide has a high specific surface area, which can prevent silicon carbide coarse powder from agglomerating during the ball milling process. It significantly improves the ball milling toughness and flowability of silicon carbide grinding powder.

[0152] Comparative analysis of Comparative Example 3, which uses microwave plasma chemical vapor deposition technology to passivate silicon carbide micropowder, with Example 2 shows that using microwave plasma chemical vapor deposition technology generates a high-hardness diamond-like film on the surface of silicon carbide powder, which significantly improves the hardness of silicon carbide grinding powder.

[0153] Comparative analysis of Comparative Example 4 (without γ-glycidoxypropyltriethoxysilane and γ-aminopropyltriethoxysilane) and Example 2 shows that the alkoxy groups in γ-glycidoxypropyltriethoxysilane and γ-aminopropyltriethoxysilane can form chemical bonds with the hydroxyl groups on the surface of silicon carbide micropowder, forming a silane coupling agent intermediate layer on the surface of silicon carbide micropowder. Then, using lauryl methacrylate and perfluorooctyl acrylate as acrylic acid graft polymerization monomers, sodium persulfate as an initiator, and ferrous sulfate as a reducing agent, the acrylic acid graft polymerization monomers are grafted onto the silane coupling agent intermediate layer to form an organic polymer coating layer. The treated silicon carbide micropowder has strong charge, and inhibits particle aggregation through electrostatic-spatial synergistic effect, significantly improving the flowability of silicon carbide grinding powder.

[0154] Comparative analysis of Comparative Example 5 (which does not use hot isostatic pressing) and Example 2 shows that using hot isostatic pressing and adding polyethylene glycol as a dispersant promotes the closure of pores inside silicon carbide particles, facilitates atomic diffusion and grain rearrangement, improves structural density, and significantly increases the hardness of silicon carbide grinding powder.

[0155] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A high-hardness silicon carbide grinding powder and its processing technology, characterized in that: Includes the following steps: Step 1: Argon gas is introduced, and surface passivated silicon carbide micro powder, γ-glycidyl etheroxypropyltriethoxysilane, and γ-aminopropyltriethoxysilane are added to anhydrous ethanol to obtain silicon carbide intermediate; Step 2: Add lauryl methacrylate, perfluorooctyl acrylate, sodium persulfate, and ferrous sulfate to the silicon carbide intermediate, acid wash to remove impurities, wash with ultrapure water, and dry to obtain modified silicon carbide micro powder. Step 3: The modified silicon carbide micro powder is subjected to wet classification to obtain silicon carbide ultrafine powder; Step 4: Take silicon carbide ultrafine powder, add polyethylene glycol, pass argon gas through, and hot press to obtain high-hardness silicon carbide grinding powder.

2. The processing technology of high-hardness silicon carbide grinding powder according to claim 1, characterized in that: The preparation method of the surface passivated silicon carbide micro powder is as follows: take silicon carbide micro powder and deposit it for 2-4 hours under the conditions of temperature 1040-1060℃, microwave power 550-650W, and pulse bias voltage 45-55V to obtain surface passivated silicon carbide micro powder.

3. The processing technology of high-hardness silicon carbide grinding powder according to claim 1, characterized in that: The modified silicon carbide micro powder comprises the following components, in parts by weight: 0.05-0.15 parts by weight of lauryl methacrylate, 0.04-0.06 parts by weight of perfluorooctyl acrylate, 0.005-0.015 parts by weight of sodium persulfate, and 0.005-0.015 parts by weight of ferrous sulfate.

4. The processing technology of high-hardness silicon carbide grinding powder according to claim 2, characterized in that: The preparation method of the silicon carbide micro powder is as follows: add nano silicon carbide and modified silica sol to silicon carbide coarse powder, adjust the pH value to 8-10, ball mill for 39-41 hours, and dry to obtain silicon carbide micro powder.

5. The processing technology of high-hardness silicon carbide grinding powder according to claim 4, characterized in that: The modified silica sol is prepared by adding γ-aminopropyltriethoxysilane to the silica sol and reacting at 50-60℃ for 5-7 hours to obtain the modified silica sol.

6. The processing technology of high-hardness silicon carbide grinding powder according to claim 4, characterized in that: The method for preparing the silicon carbide coarse powder is as follows: dry powder and sintering aid powder are mixed, pre-ground, argon gas is introduced, the temperature is raised, and impurities are removed to obtain silicon carbide coarse powder.

7. The processing technology of high-hardness silicon carbide grinding powder according to claim 6, characterized in that: The method for preparing the dried powder is as follows: weigh sodium carbonate and iron oxide, mix them evenly to prepare a composite catalyst; weigh glucose and sodium silicate, add them to the composite catalyst, stir evenly, and dry under vacuum conditions at a temperature of 105-115℃ for 45-50 hours to obtain the dried powder.

8. The processing technology of high-hardness silicon carbide grinding powder according to claim 6, characterized in that: The preparation method of the sintering aid powder is as follows: nano-cerium oxide, methylglycine diacetic acid, ammonium hydrogen fluoride, and ammonium fluoroaluminate are added to the modified silica sol, mixed evenly, freeze-dried, and ground to obtain the sintering aid powder.

9. The processing technology of high-hardness silicon carbide grinding powder according to claim 8, characterized in that: The calcination aid powder comprises the following components, in parts by weight: 0.1-0.3 parts by weight of nano-cerium oxide, 0.005-0.015 parts by weight of methylglycine diacetic acid, 0.05-0.15 parts by weight of ammonium bifluoride, 0.05-0.15 parts by weight of ammonium fluoroaluminate, and 1-3 parts by weight of modified silica sol.

10. A high-hardness silicon carbide grinding powder prepared by the processing technology of a high-hardness silicon carbide grinding powder according to any one of claims 1-9.