Metal-based ceramic bond diamond grinding wheel and preparation method thereof

Abstract

The invention relates to the field of machine manufacturing, and particularly discloses a metal-based ceramic bond diamond grinding wheel and a preparation method thereof.The metal-based ceramic bond diamond grinding wheel comprises the following raw materials of a diamond grinding material, a reinforcing phase and a composite bond; wherein carbon fibers are selected as the reinforcing phase, the composite binding agent comprises a metal binding agent and the balance of ceramic binding agent, and the ceramic binding agent comprises the following raw materials of calcium fluoride, aluminum fluoride, lithium borate, boric acid and the balance of silicon dioxide; the preparation method comprises the following steps: S1, premixing the diamond grinding material and the reinforcing phase, then adding the composite binding agent, spraying a polyvinyl alcohol solution after mixing, and mixing and granulating to obtain granules; s2, the granules are loaded into a mold to be subjected to hot press molding to obtain a grinding wheel blank; and S3, sintering the grinding wheel blank at high temperature to obtain the metal-based ceramic bond diamond grinding wheel. The emery grinding wheel has the advantages that the abrasion resistance and the impact resistance of the grinding wheel are improved, and then the service life of the emery grinding wheel is prolonged.

Description

Technical Field

[0001] This application relates to the field of mechanical manufacturing, and more specifically, to a metal-based ceramic bonded diamond grinding wheel and its preparation method. Background Technology

[0002] In the automotive manufacturing industry, the machining quality of engine blocks and cylinder heads directly affects the performance and reliability of the entire vehicle. Among these, the grinding process for cylinder blocks and cylinder heads is a crucial step in ensuring the surface precision and smoothness of the parts. Traditional grinding processes mostly use ordinary grinding wheels for grinding; however, as the automotive industry's requirements for engine performance continue to increase, traditional grinding wheels are gradually showing their shortcomings in terms of processing efficiency, processing quality, and service life.

[0003] Traditional grinding wheels have limited material hardness and wear resistance, making them prone to wear during high-speed grinding. This leads to rapid changes in the shape of the grinding wheel, requiring frequent correction or replacement, which not only increases production costs but also affects production efficiency. Furthermore, due to the insufficient wear resistance of traditional grinding wheels, they are difficult to maintain stable grinding performance after long-term use, thus affecting the dimensional accuracy and surface quality of the machined parts and failing to meet the requirements of high-precision machining.

[0004] Therefore, further improving the wear resistance and impact resistance of grinding wheels is crucial for extending their service life. Summary of the Invention

[0005] In order to improve the wear resistance and impact resistance of grinding wheels, and thus extend the service life of diamond grinding wheels, this application provides a metal-based ceramic bonded diamond grinding wheel and its preparation method.

[0006] In a first aspect, this application provides a metal-based ceramic-bonded diamond grinding wheel, employing the following technical solution: A metal-based ceramic bonded diamond grinding wheel comprises the following raw materials in parts by weight: 40-50 parts diamond abrasive, 3-5 parts reinforcing phase and 45-55 parts composite binder; The reinforcing phase is made of carbon fiber, and the composite binder includes 65-75 wt% metal binder and the balance ceramic binder. The ceramic binder comprises the following raw materials by mass percentage: 4-6% calcium fluoride, 4-6% aluminum fluoride, 10-15% lithium borate, 25-35% boric acid and balance silicon dioxide.

[0007] By adopting the above technical solution, the diamond abrasive in this application serves as the grinding body, providing high hardness and wear resistance. Based on this, carbon fiber is used as a reinforcing phase. The high strength and high modulus of carbon fiber can absorb impact energy, inhibit crack propagation, and improve impact resistance. In this application, a combination of metal and ceramic binders is used as the bonding agent. The metal binder provides the grinding wheel with good toughness and strength, solidifying the diamond abrasive, enabling the grinding wheel to resist greater impact and wear during high-speed grinding, thereby extending the service life of the grinding wheel. Ceramic binders endow grinding wheels with good thermal and chemical stability, inhibit the softening of metal binders at high temperatures, and reduce the coefficient of thermal expansion. This reduces the difference in the coefficient of thermal expansion between the binder and the diamond abrasive, reducing the risk of interfacial separation due to thermal stress during sintering or use. Furthermore, the difference in the coefficient of thermal expansion between the ceramic and metal phases introduces a compressive stress field. During cooling, the ceramic phase shrinks less, generating compressive stress on the metal phase, inhibiting crack propagation, and improving the impact resistance of the grinding wheel. Moreover, the ceramic phase enhances the interfacial bonding with the abrasive through chemical bonding, reducing abrasive peeling during grinding.

[0008] Ultimately, this application achieves a synergistic improvement in the wear resistance, impact resistance, and service life of grinding wheels by combining the high hardness of diamond abrasive, the impact resistance of carbon fiber reinforcement, and the low coefficient of expansion and chemical stability of ceramic binder through the composite of metal matrix and ceramic binder.

[0009] Optionally, the ceramic binder comprises the following raw materials by weight percentage: 5% calcium fluoride, 5% aluminum fluoride, 12% lithium borate, 28% boric acid and the balance silicon dioxide.

[0010] By adopting the above technical solution, the addition of calcium fluoride and aluminum fluoride adjusts the melting point, improves wettability, and promotes the interfacial bonding between diamond and the binder. Boric acid, as a flux, promotes liquid-phase sintering and improves binder fluidity. Lithium borate, as a phase with a low coefficient of thermal expansion, reduces thermal stress and prevents grinding wheel cracking. Silica, as the base glassy phase, lowers the sintering temperature and forms a network structure. The combination of lithium borate and boric acid reduces the coefficient of thermal expansion, reduces thermal stress during grinding, and prevents binder cracking and abrasive shedding. Meanwhile, calcium fluoride and aluminum fluoride form a lubricating film at high temperatures, reducing grinding friction and wear, and improving the wear resistance of the grinding wheel.

[0011] In this application, calcium fluoride and aluminum fluoride are added in the form of fluorides. On the one hand, calcium fluoride itself lowers the melting temperature of the binder, promotes the formation of the liquid phase, and improves the wettability of the binder for diamond abrasive, which helps to enhance the bonding force between the binder and the abrasive. Aluminum fluoride is similar. On the other hand, the addition of fluorides can adjust the thermal expansion coefficient of the binder to be closer to that of carbon fiber, reducing interfacial stress caused by thermal expansion mismatch, preventing debonding and cracking. Moreover, fluorides form chemical bonds with metal ions in carbon fiber or binder, enhancing the interfacial bonding strength. Furthermore, fluorides reduce the surface tension of the binder melt, improving its wettability for carbon fiber, making the binder more uniformly wrap the fiber, reducing porosity and defects, and improving the quality of interfacial bonding. Ultimately, in this application, carbon fiber absorbs impact energy through mechanisms such as crack deflection and pull-out, while the fluoride-optimized interfacial bonding ensures that the fiber is not easily debonded under stress, fully utilizing the toughening effect of the fiber. In addition, the fluoride interfacial bonding improves the binding force of the binder on carbon fiber and diamond abrasive, reducing wear caused by abrasive shedding during grinding.

[0012] Optionally, the metal binder comprises the following raw materials by weight percentage: 3-6% Ag, 20-30% Sn, 20-30% Co and balance copper; More preferably: 5% Ag, 25% Sn, 25% Co and the balance copper.

[0013] By adopting the above technical solution, the metal binder is mainly composed of copper, which has excellent toughness and ductility, can absorb impact energy and prevent crack propagation. The addition of cobalt can improve the hardness and wear resistance of the metal binder and reduce abrasive wear during grinding. Silver further enhances the toughness of the metal binder through solid solution strengthening and grain boundary strengthening, making it less prone to brittle fracture under impact loads. In the composite binder, the metal binder and ceramic binder are tightly bonded to form a uniform matrix. The addition of tin can reduce interfacial tension and promote the wetting and bonding of the metal phase and ceramic phase. This reduces defects at the metal-ceramic interface, improves the interfacial bonding strength, and enhances the overall performance of the composite binder, avoiding performance degradation caused by phase separation. Ultimately, the metal binder combined with the ceramic binder in this application results in better wear resistance and grinding performance of the grinding wheel.

[0014] Optionally, the ceramic binder may also include 2-5 wt% aluminum phosphate and 1-2 wt% aluminum titanate.

[0015] By adopting the above technical solution, aluminum phosphate can form Co-OP and Sn-OP chemical bonds with cobalt and tin in the metal binder during sintering, and form a three-dimensional cross-linked network with silicon dioxide and lithium borate in the ceramic binder. This significantly improves the interfacial bonding strength of the composite binder, reduces delamination during grinding, enhances wear resistance, and can absorb impact energy, thereby improving impact resistance.

[0016] Titanium dioxide in aluminum titanate can form Cu-Ti and Sn-Ti intermetallic compounds with Cu and Sn in the metal binder, while aluminum oxide can form Si-O-Al covalent bonds with silicon dioxide in the ceramic binder, achieving bidirectional chemical anchoring at the interface between the metal binder and the ceramic binder. Moreover, the thermal expansion coefficient of aluminum titanate is close to that of the ceramic binder. Ultimately, in this application, the low expansion characteristics of aluminum titanate offset the thermal stress of the metal binder. At the same time, aluminum phosphate forms a low-melting-point liquid phase during sintering, which can fully wet the surface of the metal and ceramic binders, fill the interfacial voids, and improve the interfacial bonding tightness. Furthermore, at the high temperature of grinding, aluminum phosphate can soften again to fill the interfacial microcracks and delay crack propagation. The liquid phase filling effect of aluminum phosphate eliminates interfacial voids, aluminum titanate provides interfacial chemical bonding strength, and the liquid phase characteristics of aluminum phosphate can improve the brittleness of aluminum titanate and enhance the interface's resistance to impact fracture. Ultimately, the overall performance of the grinding wheel is better.

[0017] Optionally, the carbon fiber is added after modification treatment, which includes the following steps: 1) First, the carbon fiber is subjected to oxygen-argon atmosphere plasma treatment with a treatment power of 100-150w and a treatment time of 5-10min to obtain activated carbon fiber. 2) The activated carbon fibers were placed in an ethanol solution of vinyltriethoxysilane and reacted at 50-60℃ for 3-4 hours. After filtration and drying, the primary modified carbon fibers were obtained. 3) The primary modified carbon fiber is placed in an ethanol solution containing butyl acrylate and an initiator and reacted at 60-70℃ for 8-10 hours. After filtration, grafted carbon fiber is obtained. Then, the grafted carbon fiber is placed in an ethanol suspension containing nano-alumina and soaked under ultrasonic treatment for 2-4 hours. After filtration and drying, modified carbon fiber is obtained.

[0018] By adopting the above technical solution, carbon fibers are first subjected to plasma treatment in an oxygen atmosphere to introduce active sites on the carbon fiber surface. Then, they are treated in an ethanol solution of vinyltriethoxysilane to introduce unsaturated double bonds on the carbon fiber surface. Then, under the action of an initiator, a layer of polybutyl acrylate polymer is grafted onto the carbon fiber surface. Then, the carbon fiber is immersed in a nano-alumina ethanol suspension. The carboxyl groups on the surface of polybutyl acrylate form hydrogen bonds with the hydroxyl groups on the surface of nano-alumina, so that the nano-alumina particles are adsorbed on the carbon fiber surface. Finally, the nano-alumina particles adsorbed on the carbon fiber surface can form Al-O-Si covalent bonds with the silica in the ceramic binder, which improves the interfacial bonding strength. At the same time, the steric hindrance of the polymer layer effectively prevents the agglomeration between carbon fibers, improves the dispersion uniformity of carbon fibers, and finally produces a grinding wheel with better overall mechanical properties and wear resistance.

[0019] Optionally, during carbon fiber modification, the volume ratio of oxygen to argon in step 1) is (4-5):(5-6), and the plasma treatment power is 80-120w, with a treatment time of 5-10min. In step 2), the ethanol solution of vinyltriethoxysilane is prepared by mixing vinyltriethoxysilane with water and ethanol in a volume ratio of 1:(3-4):(8-10), and the mass ratio of activated carbon fibers to the ethanol solution of vinyltriethoxysilane is 1:(8-10). In step 3), the reaction solution is prepared by mixing butyl acrylate, initiator, acrylic acid and ethanol, and the mass ratio of butyl acrylate to acrylic acid is 1:(0.3-0.4), the amount of initiator added is 0.5-1wt% of butyl acrylate, the amount of ethanol added is 3-5 times the mass of butyl acrylate, and the mass ratio of the initial modified carbon fiber to butyl acrylate is 1:(1.2-1.5). The ethanol suspension containing nano-alumina was prepared by mixing nano-alumina, polyethyleneimine and anhydrous ethanol in a mass ratio of 1:(0.1-0.2):(6-8), and the mass ratio of grafted carbon fiber to nano-alumina was 1:(0.3-0.5).

[0020] By adopting the above technical solution, the mixed atmosphere of argon and oxygen achieves both activation and etching effects.

[0021] Optionally, during carbon fiber modification, in step 3), an aminosilane coupling agent is added to the ethanol suspension containing nano-alumina, and the amount of aminosilane coupling agent added is 3-5 wt% of the nano-alumina.

[0022] By adopting the above technical solution, the addition of aminosilane coupling agent realizes the silanization of alumina surface, introduces amino functional groups, forms covalent bonds with polyacrylate layer, enhances bonding force, and improves the adsorption stability of alumina on carbon fiber.

[0023] Optionally, the composite binder is prepared by the following method: Weigh calcium fluoride, aluminum fluoride, lithium borate, boric acid, and silicon dioxide by mass percentage, and mix them by ball milling to obtain a ceramic binder; Ag, Sn, Co and copper were weighed according to mass percentage, melted in an argon atmosphere at 1100-1200℃, then water-quenched, crushed and ball-milled to obtain a metal binder; A composite binder is prepared by mixing a ceramic binder and a metal binder in a certain proportion.

[0024] Secondly, this application provides a method for preparing a metal-based ceramic-bonded diamond grinding wheel, employing the following technical solution: A method for preparing a metal-based ceramic bonded diamond grinding wheel includes the following steps: S1. Premix diamond abrasive with reinforcing phase, then add composite binder, mix and spray in 5-8 wt% polyvinyl alcohol solution, mix and granulate to obtain granules; S2. Load the granules into the mold and pre-press them at 10-20MPa for 20-30 minutes, then press them at 180-200℃ for 30-40 minutes, and then unpress them to obtain the grinding wheel blank. S3. First, heat the grinding wheel blank to 280-320℃ and hold for 1-2 hours. Then, heat it to 600-650℃ and hold for 1-2 hours. Next, heat it to 850-920℃ and hold for 40 minutes to 1 hour. Then, cool it in the furnace to obtain a metal-based ceramic bonded diamond grinding wheel.

[0025] By adopting the above technical solution, the sintering process in this application adopts a three-step process. First, the polyvinyl alcohol binder is removed by treatment at low temperature. Then, the ceramic binder is pre-fired at medium temperature to promote the initial reaction of the ceramic binder. Finally, the metal binder is sintered at high temperature to melt and impregnate the carbon fiber and diamond.

[0026] In summary, this application has the following beneficial effects: 1. In this application, diamond abrasive is used as the grinding body, providing high hardness and wear resistance. On this basis, carbon fiber is used as the reinforcing phase. The high strength and high modulus of carbon fiber can absorb impact energy, inhibit crack propagation, and improve impact resistance. In this application, the binder is a combination of metal binder and ceramic binder. The metal binder provides the grinding wheel with good toughness and strength, and consolidates the diamond abrasive, so that the grinding wheel can resist greater impact force and wear during high-speed grinding, thereby extending the service life of the grinding wheel. 2. In this application, by combining metal matrix and ceramic binder, the high hardness of diamond abrasive, the impact resistance of carbon fiber reinforcement phase, and the low expansion coefficient and chemical stability of ceramic binder are combined to achieve a synergistic improvement in the wear resistance, impact resistance and service life of grinding wheels. Detailed Implementation

[0027] The present application will be further described in detail below with reference to the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from commercially available sources.

[0028] In the following examples, the length of the carbon fiber is 0.1-1 mm.

[0029] The following preparation examples are examples of the preparation of composite binders. Preparation Example 1 A method for preparing a composite binder includes the following steps: Based on the ceramic binder, weigh the following components by mass percentage: calcium fluoride, aluminum fluoride, lithium borate, boric acid, and silicon dioxide: 5% calcium fluoride, 5% aluminum fluoride, 12% lithium borate, 28% boric acid and the balance silicon dioxide are ball-milled and mixed at a ball-to-material ratio of 5:1, at a speed of 200 rpm for 2 hours, and then passed through a 200-mesh sieve to obtain a ceramic binder. Based on the metal binder, Ag powder, Sn powder, Co powder and copper powder were weighed according to the following mass percentages: 5% Ag, 25% Sn, 25% Co and the balance copper. They were melted at 1150℃ in an argon atmosphere, then water-quenched and crushed, and ball-milled to a powder with a particle size D50 of 5μm. The powder was then passed through a 200-mesh sieve to obtain the metal binder. A composite binder was prepared by mixing ceramic binder and metal binder in a 70:30 mass ratio in a three-dimensional mixer for 2 hours.

[0030] Preparation Example 2 A method for preparing a composite binder includes the following steps: Based on the ceramic binder, weigh the following components by mass percentage: calcium fluoride, aluminum fluoride, lithium borate, boric acid, and silicon dioxide: 4% calcium fluoride, 4% aluminum fluoride, 10% lithium borate, 25% boric acid and the balance silicon dioxide are mixed by ball milling at a ball-to-material ratio of 5:1, at a speed of 200 rpm for 2 hours, and then passed through a 200-mesh sieve to obtain a ceramic binder. Based on the metal binder, Ag powder, Sn powder, Co powder and copper powder were weighed according to the following mass percentages: 3% Ag, 20% Sn, 20% Co and the balance copper. They were melted at 1100℃ in an argon atmosphere, then water-quenched and crushed, and ball-milled to a particle size D50 of 5μm. The powder was then passed through a 200-mesh sieve to obtain the metal binder. A composite binder was prepared by mixing ceramic binder and metal binder in a 65:35 mass ratio in a three-dimensional mixer for 2 hours.

[0031] Preparation Example 3 A method for preparing a composite binder includes the following steps: Based on the ceramic binder, weigh the following components by mass percentage: calcium fluoride, aluminum fluoride, lithium borate, boric acid, and silicon dioxide: 6% calcium fluoride, 6% aluminum fluoride, 15% lithium borate, 35% boric acid and the balance silicon dioxide are mixed by ball milling at a ball-to-material ratio of 5:1, at a speed of 200 rpm for 2 hours, and then passed through a 200-mesh sieve to obtain a ceramic binder. Based on the metal binder, Ag powder, Sn powder, Co powder and copper powder were weighed according to the following mass percentages: 6% Ag, 30% Sn, 30% Co and the balance copper. They were melted at 1200℃ in an argon atmosphere, then water-quenched and crushed, and ball-milled to a powder with a particle size D50 of 5μm. The powder was then passed through a 200-mesh sieve to obtain the metal binder. A composite binder was prepared by mixing a ceramic binder and a metal binder in a 75:25 mass ratio in a three-dimensional mixer for 2 hours.

[0032] Preparation Example 4 A composite binder is prepared according to the method in Example 1, except that aluminum phosphate and aluminum titanate are added to the ceramic binder raw materials, and the mass percentage of aluminum phosphate is 3 wt% and the mass percentage of aluminum titanate is 1.5 wt%. The mass percentage of silica is adjusted accordingly. When calcium fluoride, aluminum fluoride, lithium borate, boric acid and silica are weighed and ball-milled, aluminum phosphate and aluminum titanate are also weighed.

[0033] Preparation Example 5 A composite binder is prepared according to the method in Example 1, except that aluminum phosphate and aluminum titanate are added to the ceramic binder raw materials, and the mass percentage of aluminum phosphate is 2 wt% and the mass percentage of aluminum titanate is 1 wt%. The mass percentage of silica is adjusted accordingly. When calcium fluoride, aluminum fluoride, lithium borate, boric acid and silica are weighed and ball-milled for mixing, aluminum phosphate and aluminum titanate are also weighed.

[0034] Preparation Example 6 A composite binder is prepared according to the method in Example 1, except that aluminum phosphate and aluminum titanate are added to the ceramic binder raw materials, and the mass percentage of aluminum phosphate is 5 wt% and the mass percentage of aluminum titanate is 2 wt%. The mass percentage of silica is adjusted accordingly. When calcium fluoride, aluminum fluoride, lithium borate, boric acid and silica are weighed and ball-milled, aluminum phosphate and aluminum titanate are also weighed.

[0035] Preparation Example 7 A composite binder, prepared according to the method in Example 1, except that no tin is added to the metal binder.

[0036] Preparation Example 8 A composite binder was prepared according to the method in Example 4, except that only aluminum phosphate was added to the ceramic binder.

[0037] Preparation Example 9 A composite binder was prepared according to the method in Example 4, except that only aluminum titanate was added to the ceramic binder.

[0038] Comparative Preparation Example 1 A composite binder, prepared according to the method in Example 1, except that aluminum fluoride in the ceramic binder is replaced by an equal amount of aluminum oxide.

[0039] Comparative Preparation Example 2 A composite binder, prepared according to the method in Example 1, except that calcium fluoride is not added to the ceramic binder.

[0040] Example 1

[0041] A method for preparing a metal-based ceramic bonded diamond grinding wheel includes the following steps: S1. 45 kg of diamond abrasive and 4 kg of reinforcing carbon fiber are premixed at 500 rpm for 10 min. Then, 50 kg of the composite binder prepared in Preparation Example 1 is added and the mixture is continued at 800 rpm for 20 min. After mixing, a 6 wt% polyvinyl alcohol solution is sprayed in, which is 2.5 wt% of the diamond abrasive. The mixture prepared above is then granulated to obtain granules. S2. Load the granules into the mold and pre-press them at 15MPa for 25min, then press them at 190℃ for 35min, and then release the pressure to obtain the grinding wheel blank. S3. First, heat the grinding wheel blank to 300℃ and hold for 1.5h. Then, heat it to 620℃ and hold for 1.5h. After that, heat it to 900℃ and hold for 50min. Then, cool it in the furnace to obtain a metal-based ceramic bonded diamond grinding wheel.

[0042] Example 2

[0043] A method for preparing a metal-based ceramic bonded diamond grinding wheel includes the following steps: S1. 40 kg of diamond abrasive and 3 kg of reinforcing carbon fiber are premixed at 500 rpm for 10 min. Then, 45 kg of the composite binder prepared in Preparation Example 2 is added and the mixture is continued at 800 rpm for 20 min. After mixing, a 5 wt% polyvinyl alcohol solution is sprayed in, which is 2 wt% of the diamond abrasive. The mixture prepared above is then granulated to obtain granules. S2. Load the granules into the mold and pre-press them at 10MPa for 30 minutes, then press them at 180℃ for 40 minutes, and then unpress them to obtain the grinding wheel blank. S3. First, heat the grinding wheel blank to 280℃ and hold for 2 hours. Then, heat it to 600℃ and hold for 2 hours. After that, heat it to 850℃ and hold for 1 hour. Then, cool it in the furnace to obtain a metal-based ceramic bonded diamond grinding wheel.

[0044] Example 3

[0045] A method for preparing a metal-based ceramic bonded diamond grinding wheel includes the following steps: S1. Premix 50kg of diamond abrasive with 5kg of reinforcing carbon fiber at a speed of 500rpm for 10min. Then add 55kg of the composite binder prepared in Preparation Example 3 and continue mixing at a speed of 800rpm for 20min. After mixing, spray in a polyvinyl alcohol solution with a mass fraction of 8wt%, where the polyvinyl alcohol solution is 3wt% of the diamond abrasive. Then mix and granulate the mixture to obtain granules. S2. Load the granules into the mold and pre-press them at 20MPa for 20min, then press them at 200℃ for 30min, and then release the pressure to obtain the grinding wheel blank. S3. First, heat the grinding wheel blank to 320℃ and hold for 1 hour. Then, heat it to 650℃ and hold for 1 hour. After that, heat it to 920℃ and hold for 40 minutes. Then, cool it in the furnace to obtain a metal-based ceramic bonded diamond grinding wheel.

[0046] Examples 4-9 A method for preparing a metal-based ceramic bonded diamond grinding wheel is carried out according to the method in Example 1, except that the composite binder in step S1 is selected from the composite binders prepared in Examples 4-7.

[0047] Example 10

[0048] A method for preparing a metal-based ceramic bonded diamond grinding wheel is carried out according to the method in Example 1, except that in step S1, the reinforcing phase carbon fiber is modified and added in the form of modified carbon fiber. The modification treatment specifically includes the following steps: 1) The carbon fiber is first subjected to oxygen-argon atmosphere plasma treatment, with the volume ratio of oxygen to argon being 5:5, and the plasma treatment power being 100W for 8 minutes to obtain activated carbon fiber. 2) A vinyltriethoxysilane ethanol solution was prepared by mixing vinyltriethoxysilane with water and ethanol in a volume ratio of 1:3:9. Then, activated carbon fibers were placed in the vinyltriethoxysilane ethanol solution with a mass ratio of 1:9. The reaction was carried out at 55°C for 3.5 h, and then filtered and dried to obtain the initial modified carbon fibers. 3) Prepare butyl acrylate according to the mass ratio of the initial modified carbon fiber to butyl acrylate of 1:1.3. Mix butyl acrylate, potassium persulfate initiator, acrylic acid and ethanol to prepare a reaction solution. The mass ratio of butyl acrylate to acrylic acid is 1:0.3, the amount of initiator added is 0.8 wt% of butyl acrylate, and the amount of ethanol added is 4 times the mass of butyl acrylate. Then the modified carbon fiber was placed in the above reaction solution and reacted at 65°C for 9 hours. After filtration, the grafted carbon fiber was obtained. Then the grafted carbon fibers were placed in an ethanol suspension containing nano-alumina, soaked under ultrasonic treatment for 3 hours, filtered and dried to obtain modified carbon fibers. The ethanol suspension containing nano-alumina was prepared by mixing nano-alumina, polyethyleneimine, anhydrous ethanol, and aminosilane coupling agent KH-550. The mass ratio of nano-alumina, polyethyleneimine, and anhydrous ethanol was 1:0.2:7, the amount of aminosilane coupling agent added was 4 wt% of nano-alumina, and the mass ratio of grafted carbon fiber to nano-alumina was 1:0.4.

[0049] Example 11

[0050] A method for preparing a metal-based ceramic bonded diamond grinding wheel is carried out according to the method in Example 1, except that in step S1, the reinforcing phase carbon fiber is modified and added in the form of modified carbon fiber. The modification treatment specifically includes the following steps: 1) The carbon fiber is first subjected to oxygen-argon atmosphere plasma treatment, with the volume ratio of oxygen to argon being 5:5, and the plasma treatment power being 80W for 10min to obtain activated carbon fiber. 2) A vinyltriethoxysilane ethanol solution was prepared by mixing vinyltriethoxysilane with water and ethanol in a volume ratio of 1:3:8. Then, activated carbon fibers were placed in the vinyltriethoxysilane ethanol solution with a mass ratio of 1:8. The reaction was carried out at 50°C for 4 hours, and then filtered and dried to obtain the initial modified carbon fibers. 3) Prepare butyl acrylate according to the mass ratio of the initial modified carbon fiber to butyl acrylate of 1:1.2. Mix butyl acrylate, potassium persulfate initiator, acrylic acid and ethanol to prepare a reaction solution. The mass ratio of butyl acrylate to acrylic acid is 1:0.3. The amount of initiator added is 0.5 wt% of butyl acrylate and the amount of ethanol added is 3 times the mass of butyl acrylate. Then the modified carbon fiber was placed in the above reaction solution and reacted at 60°C for 10 hours. After filtration, the grafted carbon fiber was obtained. Then the grafted carbon fibers were placed in an ethanol suspension containing nano-alumina, soaked under ultrasonic treatment for 2 hours, filtered and dried to obtain modified carbon fibers. The ethanol suspension containing nano-alumina was prepared by mixing nano-alumina, polyethyleneimine, anhydrous ethanol, and aminosilane coupling agent KH-550. The mass ratio of nano-alumina, polyethyleneimine, and anhydrous ethanol was 1:0.1:6, the amount of aminosilane coupling agent added was 3 wt% of nano-alumina, and the mass ratio of grafted carbon fiber to nano-alumina was 1:0.3.

[0051] Example 12

[0052] A method for preparing a metal-based ceramic bonded diamond grinding wheel is carried out according to the method in Example 1, except that in step S1, the reinforcing phase carbon fiber is modified and added in the form of modified carbon fiber. The modification treatment specifically includes the following steps: 1) The carbon fiber is first subjected to oxygen-argon atmosphere plasma treatment, with the volume ratio of oxygen to argon being 4:6, and the plasma treatment power being 120W for 5 minutes to obtain activated carbon fiber. 2) A vinyltriethoxysilane ethanol solution was prepared by mixing vinyltriethoxysilane with water and ethanol in a volume ratio of 1:4:10. Then, activated carbon fibers were placed in the vinyltriethoxysilane ethanol solution with a mass ratio of 1:10. The reaction was carried out at 60°C for 3 hours, and then filtered and dried to obtain the initial modified carbon fibers. 3) Prepare butyl acrylate according to the mass ratio of the initial modified carbon fiber to butyl acrylate of 1:1.5. Mix butyl acrylate, potassium persulfate initiator, acrylic acid and ethanol to prepare a reaction solution. The mass ratio of butyl acrylate to acrylic acid is 1:0.4. The amount of initiator added is 1 wt% of butyl acrylate and the amount of ethanol added is 5 times the mass of butyl acrylate. Then the modified carbon fiber was placed in the above reaction solution and reacted at 70°C for 8 hours. After filtration, the grafted carbon fiber was obtained. Then the grafted carbon fibers were placed in an ethanol suspension containing nano-alumina, soaked under ultrasonic treatment for 4 hours, filtered and dried to obtain modified carbon fibers. The ethanol suspension containing nano-alumina was prepared by mixing nano-alumina, polyethyleneimine, anhydrous ethanol, and aminosilane coupling agent KH-550. The mass ratio of nano-alumina, polyethyleneimine, and anhydrous ethanol was 1:0.2:8, the amount of aminosilane coupling agent added was 5 wt% of nano-alumina, and the mass ratio of grafted carbon fiber to nano-alumina was 1:0.5.

[0053] Comparative Examples 1-2 A method for preparing a metal-based ceramic bonded diamond grinding wheel is carried out according to the method in Example 1, except that the ceramic bond is selected from the ceramic bond prepared in Comparative Preparation Example 1 and Comparative Preparation Example 2, respectively.

[0054] Comparative Example 3 A method for preparing a metal-based ceramic-bonded diamond grinding wheel is carried out according to the method in Example 1, except that the ceramic binder is replaced by an equal amount of metal binder.

[0055] Comparative Example 4 A method for preparing a metal-based ceramic-bonded diamond grinding wheel is carried out according to the method in Example 1, except that the metal binder is replaced by an equal amount of ceramic binder.

[0056] Performance testing The diamond grinding wheels obtained in the above embodiments and comparative examples were subjected to impact strength testing using an XJ-300A impact testing machine. Referring to GB / T6569-2006 standard, the bending strength was tested using the three-point bending strength method on an SKZ-500 digital display bending strength testing machine. Additionally, the wear ratio (×10) was calculated in accordance with GB / T 6569-2006. 3 The wear resistance was characterized by testing, and the test results are shown in Table 1 below.

[0057] Table 1:

[0058] Based on the test results in Table 1 above, the diamond grinding wheel prepared in this application embodiment has excellent impact strength as well as good bending strength and wear resistance. Based on the test results of Examples 1 and 4-6, when aluminum phosphate and aluminum titanate are added to the ceramic binder, its impact strength is improved. The introduction of chemically bonded phases in the ceramic binder enhances interfacial bonding, inhibits crack propagation, and improves bending strength and wear ratio. Its low expansion coefficient raw material reduces phase separation caused by thermal stress. Based on the test results of Example 7, when tin is not added to the metal binder in Example 7, its impact strength and wear resistance are reduced. Based on the test results of Examples 8 and 9, when aluminum phosphate or aluminum titanate is added alone to the ceramic binder, its effect is reduced compared to Example 4.

[0059] Combining the test results of Examples 1 and 10-12, the addition of modified carbon fiber synergistically improves its impact strength, flexural strength, and wear resistance. The surface polymer layer of the modified carbon fiber helps inhibit agglomeration, promotes uniform dispersion in the matrix, and facilitates good chemical bonding with the binder. Combining the test results of Examples 1 and Comparative Examples 1 and 2, when the ceramic binder is added in oxide form, the wear resistance is lower than in Example 1. Fluorides help improve wear resistance by adjusting the melting point and improving wettability. Combining the test results of Comparative Examples 3 and 4, when a metal binder is used in Comparative Example 3, the impact strength and flexural strength are significantly reduced. When a ceramic binder is used in Comparative Example 4, the flexural strength is low. The brittleness of the ceramic binder limits the mechanical properties. The metal binder and ceramic composite binder achieve a balance in toughness.

[0060] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A metal-based ceramic-bonded diamond grinding wheel, characterized in that, Including the following parts by weight of raw materials: 40-50 parts diamond abrasive, 3-5 parts reinforcing phase and 45-55 parts composite binder; The reinforcing phase is made of carbon fiber, and the composite binder includes 65-75 wt% metal binder and the balance ceramic binder. The ceramic binder comprises the following raw materials by mass percentage: 4-6% calcium fluoride, 4-6% aluminum fluoride, 10-15% lithium borate, 25-35% boric acid and balance silicon dioxide.

2. The metal-based ceramic bonded diamond grinding wheel according to claim 1, characterized in that: The ceramic binder comprises the following raw materials by weight percentage: 5% calcium fluoride, 5% aluminum fluoride, 12% lithium borate, 28% boric acid and the balance silicon dioxide.

3. The metal-based ceramic bonded diamond grinding wheel according to claim 1, characterized in that: The metal binder comprises the following raw materials by weight percentage: 3-6% Ag, 20-30% Sn, 20-30% Co and the balance copper.

4. The metal-based ceramic bonded diamond grinding wheel according to claim 1, characterized in that: The metal binder comprises the following raw materials by weight percentage: 5% Ag, 25% Sn, 25% Co and the balance copper.

5. The metal-based ceramic bonded diamond grinding wheel according to claim 1, characterized in that: The ceramic binder also includes 2-5 wt% aluminum phosphate and 1-2 wt% aluminum titanate.

6. The metal-based ceramic bonded diamond grinding wheel according to claim 1, characterized in that: The carbon fiber is added after modification treatment, which includes the following steps: 1) The carbon fiber is first subjected to oxygen-argon atmosphere plasma treatment to obtain activated carbon fiber; 2) The activated carbon fibers were placed in an ethanol solution of vinyltriethoxysilane and reacted at 50-60℃ for 3-4 hours. After filtration and drying, the primary modified carbon fibers were obtained. 3) The modified carbon fiber is placed in a reaction solution containing butyl acrylate and an initiator and reacted at 60-70℃ for 8-10 hours. After filtration, the grafted carbon fiber is obtained. Then, the grafted carbon fiber is placed in an ethanol suspension containing nano-alumina and soaked under ultrasonic treatment for 2-4 hours. After filtration and drying, the modified carbon fiber is obtained.

7. The metal-based ceramic bonded diamond grinding wheel according to claim 6, characterized in that: When modifying carbon fiber, the volume ratio of oxygen to argon in step 1) is (4-5):(5-6), and the plasma treatment power is 80-120w, and the treatment time is 5-10min. In step 2), the ethanol solution of vinyltriethoxysilane is prepared by mixing vinyltriethoxysilane with water and ethanol in a volume ratio of 1:(3-4):(8-10), and the mass ratio of activated carbon fibers to the ethanol solution of vinyltriethoxysilane is 1:(8-10). In step 3), the reaction solution is prepared by mixing butyl acrylate, initiator, acrylic acid and ethanol, and the mass ratio of butyl acrylate to acrylic acid is 1:(0.3-0.4), the amount of initiator added is 0.5-1wt% of butyl acrylate, the amount of ethanol added is 3-5 times the mass of butyl acrylate, and the mass ratio of the initial modified carbon fiber to butyl acrylate is 1:(1.2-1.5). The ethanol suspension containing nano-alumina was prepared by mixing nano-alumina, polyethyleneimine and anhydrous ethanol in a mass ratio of 1:(0.1-0.2):(6-8), and the mass ratio of grafted carbon fiber to nano-alumina was 1:(0.3-0.5).

8. The metal-based ceramic bonded diamond grinding wheel according to claim 6, characterized in that: During carbon fiber modification, in step 3), an aminosilane coupling agent is added to the ethanol suspension containing nano-alumina, and the amount of aminosilane coupling agent added is 3-5 wt% of the nano-alumina.

9. A metal-based ceramic-bonded diamond grinding wheel according to claim 3, characterized in that: The composite binder is prepared by the following method: Weigh calcium fluoride, aluminum fluoride, lithium borate, boric acid, and silicon dioxide by mass percentage, and mix them by ball milling to obtain a ceramic binder; Ag, Sn, Co and copper were weighed according to mass percentage, melted in an argon atmosphere at 1100-1200℃, then water-quenched, crushed and ball-milled to obtain a metal binder; A composite binder is prepared by mixing a ceramic binder and a metal binder in a certain proportion.

10. The method for preparing a metal-based ceramic-bonded diamond grinding wheel according to any one of claims 1-9, characterized in that: Includes the following steps: S1. Premix diamond abrasive with reinforcing phase, then add composite binder, mix and spray in 5-8 wt% polyvinyl alcohol solution, mix and granulate to obtain granules; S2. Load the granules into the mold and pre-press them at 10-20MPa for 20-30 minutes, then press them at 180-200℃ for 30-40 minutes, and then unpress them to obtain the grinding wheel blank. S3. First, heat the grinding wheel blank to 280-320℃ and hold for 1-2 hours. Then, heat it to 600-650℃ and hold for 1-2 hours. Next, heat it to 850-920℃ and hold for 40 minutes to 1 hour. Then, cool it in the furnace to obtain a metal-based ceramic bonded diamond grinding wheel.

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