Diamond reinforced alumina slurry suitable for DLP printing and preparation method thereof

Abstract

The invention discloses diamond reinforced alumina slurry suitable for DLP printing and a preparation method thereof.The slurry is grafted with modified diamond particles through a coupling agent and a polymer, polar groups such as hydroxyl groups and epoxy groups are introduced to the surfaces of the diamond particles through hydrolysis and combination reactions, and the interface bonding force with alumina particles is enhanced; the problem of interfacial compatibility of diamond particles and aluminum oxide is solved, uniform dispersion of the particles and resin is ensured by adopting a three-step composite dispersion process, namely a ball milling-vacuum stirring composite dispersion process, the overall uniformity of the diamond-enhanced aluminum oxide slurry is ensured by adopting a vacuum homogenizer, and the obtained slurry is moderate in viscosity, high in light curing speed and high in strength. The printed and formed ceramic part has excellent mechanical property and wear resistance after being sintered, and is suitable for rapid manufacturing of high-precision complex ceramic parts.

Description

Technical Field

[0001] This invention belongs to the field of photopolymerization 3D printing technology, and specifically relates to a diamond-reinforced alumina slurry suitable for DLP printing and its preparation method. Background Technology

[0002] As a novel additive manufacturing process that has emerged in recent years, 3D printing has been industrialized in numerous industries, including military, aerospace, intelligent equipment, transportation engineering, and healthcare, thanks to its high-efficiency output, complex structure forming, precision machining characteristics, and ability to meet customized needs. Among these, digital optical processing (DLP) based forming systems have attracted much attention in the field of rapid manufacturing of ceramic parts due to their fast forming speed and high precision.

[0003] Alumina ceramics (Al2O3) are widely used in electronic packaging, structural components, and other fields due to their high hardness, wear resistance, and high temperature resistance. However, traditional single alumina pastes have the following drawbacks: 1. The mechanical properties of a single alumina matrix are limited, and it is prone to failure, especially under high load or wear conditions; 2. Uneven dispersion of ceramic particles in the slurry leads to poor flowability during printing and high shrinkage rate after curing; 3. The existing reinforcing phases (such as silicon carbide and carbon fiber) have insufficient interfacial bonding with alumina, making it difficult to synergistically improve material performance.

[0004] Diamond, as the hardest known material, can significantly improve the wear resistance and rigidity of composite materials when combined with alumina. However, diamond has a strong surface inertness, poor compatibility with polar alumina matrix, and is prone to agglomeration in the slurry, leading to slurry stratification and insufficient curing during DLP printing.

[0005] Therefore, it is of great significance to develop a diamond-reinforced alumina slurry with uniform dispersion and excellent photocuring properties. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the prior art by providing a diamond-reinforced alumina slurry suitable for DLP printing and its preparation method, thereby solving the interfacial compatibility problem between diamond and alumina through optimization of the composition and preparation process.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A diamond-reinforced alumina slurry suitable for DLP printing comprises the following components by weight percentage: 60%-78% alumina ceramic particles, 5%-15% modified diamond particles, 15%-25% photocurable resin system, 0.5%-2% dispersant, and 0.1%-1% slurry additives, wherein the surface of the diamond particles is modified by coupling agent or polymer grafting.

[0008] The coupling agent is a silane coupling agent with a particle size of 0.5-2 μm.

[0009] The alumina ceramic particles have a particle size of 1-5 μm.

[0010] The photocurable resin system comprises a photosensitive prepolymer, an active diluent, and a photoinitiator.

[0011] The dispersant is one or a combination of epoxy-containing coupling agents, acid-containing copolymers, amphoteric polymers, and amino acid ester copolymers.

[0012] The slurry additives include defoamers and leveling agents.

[0013] A method for preparing a diamond-reinforced alumina paste suitable for DLP printing includes the following steps: (1) Diamond surface modification Surface-modified diamond particles are obtained by surface treatment with a surface modifier. (2) Powder ball milling dispersion Modified diamond particles, alumina ceramic particles and ball milling solvent are mixed and added to a ball mill for ball milling to obtain uniformly dispersed alumina and diamond powder. (3) Preparation of light-curing resin system Weigh the photosensitive prepolymer, reactive diluent, photoinitiator and defoamer according to the proportions, mix and stir evenly, and then put them into a vacuum mixer to stir evenly. (4) Slurry preparation The alumina and diamond powder dispersed by ball milling are thoroughly mixed with the prepared photocurable resin system, dispersant and defoamer, and then homogenized and dispersed in a vacuum homogenizer to obtain a uniformly dispersed diamond-reinforced alumina slurry.

[0014] In step (3), the ratio of photosensitive prepolymer to reactive diluent in the photocurable resin system is 1:2-1:10.

[0015] In step (4), the viscosity of the diamond-reinforced alumina slurry is 500-1500 mPa·s at room temperature.

[0016] During ball milling, the rotation speed is 200-500 rpm and the time is 4-12 h; during vacuum stirring, the vacuum degree is 10⁻¹ Pa - 10⁻³ Pa, the rotation speed is 50-500 rpm, and the time is 2-10 min; during vacuum homogenization, the vacuum degree is 10⁻¹ Pa - 10⁻³ Pa, the rotation speed is 800-2000 rpm, and the time is 1-5 min.

[0017] The beneficial effects of this invention are: (1) This invention discloses a diamond-reinforced alumina slurry suitable for DLP printing and its preparation method. The slurry modifies diamond particles by using coupling agents and polymer grafting. Polar groups such as hydroxyl and epoxy groups are introduced on the surface of the slurry through hydrolysis and chemical reaction to enhance the interfacial bonding force with alumina particles. This solves the problem of interfacial compatibility between diamond particles and alumina. A three-step composite dispersion process is adopted, namely, a ball mill-vacuum stirring composite dispersion process to ensure uniform dispersion of particles and resin, and a vacuum homogenizer to ensure the overall uniformity of the diamond-reinforced alumina slurry. The resulting slurry has moderate viscosity and fast photocuring speed. The printed ceramic parts have excellent mechanical properties and wear resistance after sintering, and are suitable for the rapid manufacturing of high-precision complex ceramic parts.

[0018] (2) The “three-step” composite dispersion process: First, alumina and modified diamond are added to the dispersant solution and ball-milled. Second, photosensitive resin is prepared and stirred by a vacuum mixer to ensure that the photosensitive oligomer, active diluent, photoinitiator and defoamer are mixed evenly. Third, slurry is prepared. After the diamond alumina powder is mixed evenly with the photocurable resin system, high-speed vacuum homogenization is performed to ensure the uniformity of the dispersion of diamond and alumina particles in the resin system. The dispersion uniformity is ≤5μm.

[0019] (3) Optimization of photocuring system: By adjusting the ratio of photosensitive prepolymer to reactive diluent in the photosensitive resin system (1:2-1:10), the viscosity of the slurry is controlled at 500-1500 mPa·s (25℃) to meet the leveling and curing speed requirements of DLP printing (curing time 5-15s / layer).

[0020] (4) High dispersion, excellent printing performance, process compatibility and mechanical properties are improved. Attached Figure Description

[0021] Figure 1 This is a flow chart of the slurry preparation process of the present invention; Figure 2 This is a schematic diagram of the interfacial bonding between modified diamond and alumina particles; Figure 3 This is a schematic diagram of an alumina-diamond composite material sample formed by DLP printing. Detailed Implementation

[0022] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. 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. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. 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.

[0024] This invention provides a diamond-reinforced alumina paste suitable for DLP printing and its preparation method, such as... Figures 1 to 3 As shown.

[0025] A diamond-reinforced alumina slurry suitable for DLP printing comprises the following components by mass percentage: 60%-78% alumina ceramic particles, 5%-15% modified diamond particles, 15%-25% photocurable resin system, 0.5%-2% dispersant, and 0.1%-1% slurry additives. The surface of the diamond particles is modified by coupling agent or polymer grafting. The coupling agent is a silane coupling agent with a particle size of 0.5-2 μm. The alumina ceramic particles have a particle size of 1-5 μm and a purity ≥99.8%.

[0026] The photocurable resin system includes photosensitive prepolymer, reactive diluent, and photoinitiator; while the photosensitive prepolymer (such as acrylates), reactive diluent (such as one or more acrylate diluents such as tripropylene glycol diacrylate, trimethylolpropane triacrylate, hexanediol diacrylate, and dipentaerythritol hexaacrylate) and photoinitiator (such as benzoin dimethyl ether) etc.

[0027] The dispersant is one or a combination of epoxy-containing coupling agent KH-560, acid-containing copolymer KOS110, amphoteric polymer KOS163, and amino acid ester copolymer Solsperse20000.

[0028] The slurry additives include defoamers, such as silicones; and leveling agents, such as acrylate leveling agents.

[0029] A method for preparing a diamond-reinforced alumina paste suitable for DLP printing includes the following steps: (1) Diamond surface modification Surface-modified diamond particles are obtained by surface treatment with surface modifiers. Silane coupling agents, such as KH-560, or polymer grafting, such as maleic anhydride, can be used to treat the diamond particles. Through hydrolysis and chemical reactions, polar groups such as hydroxyl and epoxy groups are introduced on the surface to enhance the interfacial bonding force with alumina particles.

[0030] (2) Powder ball milling dispersion Modified diamond particles and alumina ceramic particles are mixed with a ball milling solvent and then ball milled in a ball mill to obtain uniformly dispersed alumina and diamond powders. The ball milling solvent, i.e., the dispersant solution, can be one or a combination of anhydrous ethanol, acetone, or isopropanol. The ball milling process is carried out at a speed of 200-500 rpm for 4-12 hours.

[0031] (3) Preparation of light-curing resin system Weigh the photosensitive prepolymer, reactive diluent, photoinitiator, and defoamer according to the specified ratio, mix them thoroughly, and then place them in a vacuum mixer to stir evenly; the vacuum degree of the vacuum mixer is 10. -1 Pa-10 -3 The rotation speed is 50-500 rpm, and the time is 2-10 min to ensure that the photosensitive oligomer, reactive diluent, photoinitiator and defoamer are mixed evenly.

[0032] (4) Slurry preparation The alumina and diamond powders, after being dispersed by ball milling, were thoroughly mixed with the prepared photosensitive resin, dispersant, and defoamer, and then homogenized and dispersed in a vacuum homogenizer with a vacuum degree of 10. -1 Pa-10 -3 Pa, rotation speed of 800-2000 rpm, time of 1-5 min; to obtain a uniformly dispersed diamond-reinforced alumina slurry with a dispersion uniformity ≤5μm.

[0033] Preferably, the ratio of photosensitive prepolymer to reactive diluent in the photocurable resin system is 1:2-1:10, and the viscosity of diamond-reinforced alumina slurry is 500-1500 mPa·s at room temperature (25°C) to meet the leveling and curing speed requirements of DLP printing (curing time 5-15 s / layer).

[0034] The ball milling process is performed at a speed of 200-500 rpm for 4-12 hours; the vacuum degree during vacuum stirring is 10. -1 Pa-10 -3 Pa, rotation speed 50-500 rpm, time 2-10 min; vacuum degree in the vacuum homogenizer is 10 -1 Pa-10 -3 Pa, speed 800-2000 rpm, time 1-5 min.

[0035] The following description, in conjunction with specific embodiments, provides further details: Example 1 Slurry composition (by mass percentage) • Alumina particles: 70%, particle size 2-4μm; • Modified diamond particles: 10% (KH-560 modified), particle size 1μm; • Photocurable resin system: 18% (resin system percentage: 98%, of which dipentaerythritol hexaacrylate: tripropylene glycol diacrylate: bisphenol A content ratio = 5:4:1, photoinitiator content 2%) • Dispersant: 1.5% of the acid-containing copolymer KOS110; • Slurry additives: 0.5%, including 0.3% silicone defoamer and 0.2% acrylate leveling agent.

[0036] Preparation steps (1) Diamond surface modification: Diamond was surface treated with 1.5% wt silane coupling agent for 2 hours.

[0037] (2) Ball milling dispersion: The modified diamond and alumina powders were added to anhydrous ethanol solution (100% of the powder mass) in a certain proportion and ball-milled at a speed of 400 rpm for 6 hours with a ball-to-powder ratio of 5:1.

[0038] (3) Photosensitive resin ratio: Weigh and mix 8.82% dipentaerythritol hexaacrylate, 7.06% tripropylene glycol diacrylate, 1.8% bisphenol A, 0.36% trimethylbenzoyl (TPO) and 0.3% silicone defoamer. After mixing thoroughly, stir evenly using a vacuum mixer (100 rpm, 10⁻¹ Pa) for 3 minutes.

[0039] (4) Slurry preparation: The alumina dispersed by ball milling was mixed with diamond powder, photosensitive resin, 1.5% KOS110, and 0.2% acrylate. After mixing, the mixture was subjected to high-speed vacuum homogenization treatment (vacuum degree 10-1 Pa, rotation speed 1500 rpm, time 2 min) to ensure the uniformity of the dispersion of diamond and alumina particles in the resin system, with a dispersion uniformity ≤5μm.

[0040] (5) DLP printing: The printing equipment used was a BMF-S240, with the following parameters: laser power 50mw / cm2, exposure time 3s, cured layer thickness 30μm, slurry leveling time 50s, and squeegee frequency 3 times / layer.

[0041] (6) Degreasing and sintering: The printed sample was placed in a tube furnace filled with argon gas and heated to 600°C at a rate of 1°C / min. It was held at this temperature for 30 minutes for degreasing treatment, and then slowly heated to 1650°C at a rate of 0.5°C / min. After holding at this temperature for 1 hour, it was cooled to room temperature with the furnace.

[0042] Performance testing • Slurry viscosity: 850 mPa·s (25℃); • Laser curing power: Printed layer thickness: 25μm, curing time: 2s / layer; • Sintered flexural strength: 385MPa, hardness HV 1850, volumetric wear rate: 0.02mm³ / N・m.

[0043] Example 2 (Unmodified diamond comparison group) ① Slurry composition (mass percentage) • Unmodified diamond particles were used: 10%, and the remaining components and manufacturing steps were the same as in Example 1.

[0044] ② Performance differences • The slurry contains 12% particulate aggregates, which cause interlayer delamination during printing; • After sintering, the flexural strength is 260MPa, the hardness is HV 1300, and the wear rate is 0.05mm³ / N・m.

[0045] Example 3 (High Diamond Content Group) Slurry composition (by weight): • Alumina particles: 45%, particle size 1-3μm; • Modified diamond particles: 35%, modified with maleic anhydride grafting, particle size 0.8μm; • Photocurable resin system: 18% (photosensitive prepolymer: reactive diluent = 1:8, wherein the photosensitive prepolymer is bisphenol A epoxy acrylate, the reactive diluent is hexanediol diacrylate, and the photoinitiator accounts for 2.5% of the resin system). • Dispersant: 1.2%, and KH-560 and Solsperse20000 are compounded in a 1:1 ratio; • Slurry additives: 0.8%, namely 0.5% silicone defoamer and 0.3% acrylate leveling agent.

[0046] Preparation steps: (1) Diamond surface modification: Treatment with 2% wt maleic anhydride for 3 hours introduces hydroxyl groups.

[0047] (2) Ball milling dispersion: Anhydrous ethanol was used as the solvent (120% of the powder mass), the rotation speed was 500 rpm, the time was 8 hours, and the ball-to-powder ratio was 6:1.

[0048] (3) Preparation of light-curing resin: Use a vacuum mixer with a vacuum level of 10⁻² Pa and a speed of 200 rpm for 5 minutes.

[0049] (4) Slurry preparation: Vacuum homogenizer with a vacuum degree of 10⁻² Pa, a rotation speed of 1800 rpm, and a time of 3 min, achieves a dispersion uniformity of ≤4 μm.

[0050] (5) Printing and sintering: The printing equipment used was a BMF-S240, with parameters set as follows: laser power 60mw / cm², exposure time 4s, and curing layer thickness 25μm per layer; degreasing heating rate 1℃ / min to 650℃ and holding for 40min; sintering heating rate 0.5℃ / min to 1700℃ and holding for 1.5h.

[0051] In this embodiment, a high diamond content can improve wear resistance, while the compound dispersant enhances particle dispersion stability.

[0052] Example 4 (Low Viscosity Slurry Group) Slurry composition (by weight): Alumina particles 65% (particle size 1-2μm); 5% modified diamond particles (KH-560 modified, particle size 0.5μm); The photocurable resin system comprises 29% (photosensitive prepolymer: reactive diluent = 1:10, the photosensitive prepolymer is polyurethane acrylate, the reactive diluent is trimethylolpropane triacrylate, and the photoinitiator accounts for 2% of the resin system). Dispersant 0.8% (KOS163); Slurry additives 0.2% (organic silicone defoamer 0.1% + acrylate leveling agent 0.1%).

[0053] Preparation steps: (1) Diamond surface modification: Surface treatment of diamond with 1% wt KH-560 for 1.5 hours.

[0054] (2) Ball milling dispersion: Isopropanol was used as the solvent (80% of the powder mass), the rotation speed was 300 rpm, the time was 4 h, and the ball-to-powder ratio was 4:1.

[0055] (3) Preparation of light-curing resin: Use a vacuum mixer with a vacuum level of 10⁻³ Pa and a speed of 150 rpm for 2 minutes.

[0056] (4) Slurry preparation: Vacuum homogenizer with a vacuum degree of 10⁻³ Pa, a rotation speed of 1200 rpm, and a time of 1 min, achieves a dispersion uniformity of ≤3 μm.

[0057] (5) Printing and sintering: The printing equipment used was a BMF-S240, with parameters set as follows: laser power 45mw / cm², exposure time 2s, and curing layer thickness 20μm per layer; degreasing heating rate 1℃ / min to 600℃ and holding for 30min; sintering heating rate 0.5℃ / min to 1600℃ and holding for 1h.

[0058] In this embodiment, the low-viscosity slurry is suitable for printing with a fine layer thickness of 20μm, which meets the requirements for printing high-precision micro parts.

[0059] Example 5 (High alumina content group) Slurry composition (by weight): • Alumina particles: 80%, particle size 3-5μm, purity 99.9%; • Modified diamond particles: 5% (KH-560 and maleic anhydride composite modification, particle size 1.5μm); • Photocurable resin system: 13% (photosensitive prepolymer: reactive diluent = 1:5, photosensitive prepolymer is epoxy acrylate, reactive diluent is tripropylene glycol diacrylate, photoinitiator accounts for 3% of the resin system); • Dispersant: 1.5% (KOS110); • Slurry additives: 0.5%, including 0.3% silicone defoamer and 0.2% acrylate leveling agent.

[0060] Preparation steps: (1) Diamond surface modification: Diamond was surface treated with 1.8% wt composite modifier (KH-560: maleic anhydride = 2:1) for 2.5 hours.

[0061] (2) Ball milling dispersion: A mixture of acetone and anhydrous ethanol (volume ratio 1:1, powder mass 110%) was used at a rotation speed of 450 rpm for 12 hours, with a ball-to-particle ratio of 5:1.

[0062] (3) Preparation of light-curing resin: Use a vacuum mixer with a vacuum level of 10⁻² Pa and a speed of 300 rpm for 8 minutes.

[0063] (4) Slurry preparation: Vacuum homogenizer with a vacuum degree of 10⁻² Pa, a rotation speed of 2000 rpm, and a time of 4 min, achieves a dispersion uniformity of ≤5 μm.

[0064] (5) Printing and sintering: The printing equipment used was BMF-S240, with a laser power of 55mw / cm², an exposure time of 5s, and a layer thickness of 35μm. The degreasing heating rate was 1℃ / min to 700℃ and held for 50min, and the sintering heating rate was 0.5℃ / min to 1680℃ and held for 2h.

[0065] In this embodiment, the high alumina content increases the matrix strength, and the composite modification enhances the interfacial bonding force.

[0066] Example 6 (Control group without dispersant) Slurry composition (by weight): Same as Example 1, but with the dispersant (acid-containing copolymer KOS110) removed, and the proportions of the remaining components unchanged, namely 70% alumina, 10% modified diamond, 18% photocurable resin system, and 0.5% slurry additives.

[0067] Preparation steps: Except for the absence of a dispersant, the remaining steps—diamond modification, ball milling, resin preparation, homogenization, printing and sintering—are exactly the same as in Example 1.

[0068] This embodiment compares the effects of dispersants on slurry dispersibility and part performance to verify the necessity of dispersants.

[0069] The performance test results of the above embodiments are shown in Table 1 below: Table 1 Performance test results for each embodiment Therefore, it can be seen that surface treatment of diamond particles with silane coupling agents (such as KH-560) or polymer grafting (such as maleic anhydride) introduces polar groups such as hydroxyl and epoxy groups on their surface through hydrolysis and chemical reactions, which significantly enhances the interfacial bonding force with alumina particles.

[0070] The diamond-reinforced alumina slurry suitable for DLP printing disclosed in this invention and the preparation method thereof produce a slurry with the following properties: 1. High dispersibility: Due to the modification of the diamond particle surface, the modified diamond-reinforced alumina slurry forms a strong interfacial bond at the junction of diamond and alumina. Combined with the ball milling-high-speed homogenization composite dispersion process, the proportion of particle agglomerates in the slurry is less than 3%, ensuring tight interlayer bonding during printing.

[0071] 2. Excellent printing performance: The paste has a moderate viscosity and can achieve precise molding of 20-80μm layer thickness on DLP equipment. The dimensional accuracy error of the preform after curing is ≤±1%.

[0072] 3. Process compatibility: It is suitable for mainstream DLP printing equipment and can form complex structural parts (such as parts with internal holes, thin-walled parts, complex through-hole structures, etc.), which broadens the application scenarios of alumina ceramic 3D printing.

[0073] 4. Improved mechanical properties: After high-temperature sintering, the flexural strength of the diamond alumina composite material can reach 350-450MPa, and the hardness (HV) ≥1800, which is 40%-60% higher than that of single alumina ceramics, and the wear resistance (volume wear rate) is reduced by more than 50%.

[0074] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this invention is defined by the appended claims and their equivalents.

[0075] The endpoints and any values ​​of the ranges disclosed herein are not limited to the exact ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0076] In the description of this invention, it should be understood that the terms "front", "rear", "left", "right", "center", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of this invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

Claims

1. A diamond-reinforced alumina paste suitable for DLP printing, characterized in that, It includes the following components by weight percentage: 60%-78% alumina ceramic particles, 5%-15% modified diamond particles, 15%-25% UV-curable resin system, 0.5%-2% dispersant, and 0.1%-1% slurry additives, and the surface of the diamond particles is modified by coupling agent or polymer grafting.

2. The diamond-reinforced alumina paste suitable for DLP printing according to claim 1, characterized in that: The coupling agent is a silane coupling agent with a particle size of 0.5-2 μm.

3. The diamond-reinforced alumina paste suitable for DLP printing according to claim 1 is characterized in that: The alumina ceramic particles have a particle size of 1-5 μm.

4. The diamond-reinforced alumina paste suitable for DLP printing according to claim 1, characterized in that: The photocurable resin system comprises a photosensitive prepolymer, an active diluent, and a photoinitiator.

5. A diamond-reinforced alumina paste suitable for DLP printing according to claim 1, characterized in that: The dispersant is one or a combination of epoxy-containing coupling agents, acid-containing copolymers, amphoteric polymers, and amino acid ester copolymers.

6. A diamond-reinforced alumina paste suitable for DLP printing according to claim 1, characterized in that: The slurry additives include defoamers and leveling agents.

7. A method for preparing a diamond-reinforced alumina paste suitable for DLP printing according to any one of claims 1 to 6, characterized in that, Includes the following steps: (1) Diamond surface modification Surface-modified diamond particles are obtained by surface treatment with a surface modifier. (2) Powder ball milling dispersion Modified diamond particles and alumina ceramic particles are mixed with a ball milling solvent and then ball milled to obtain uniformly dispersed alumina and diamond powder. (3) Preparation of light-curing resin system Weigh the photosensitive prepolymer, reactive diluent, photoinitiator and defoamer according to the proportions, mix and stir evenly, and then put them into a vacuum mixer to stir evenly. (4) Slurry preparation The alumina and diamond powder dispersed by ball milling were thoroughly mixed with the prepared photocurable resin system, dispersant and defoamer, and then homogenized and dispersed in a vacuum homogenizer to obtain a uniformly dispersed diamond-reinforced alumina slurry.

8. A method for preparing a diamond-reinforced alumina paste suitable for DLP printing according to claim 7, characterized in that: In step (3), the ratio of photosensitive prepolymer to reactive diluent in the photocurable resin system is 1:2 to 1:

10.

9. A method for preparing a diamond-reinforced alumina paste suitable for DLP printing according to claim 7, characterized in that: In step (4), the viscosity of the diamond-reinforced alumina slurry is 500-1500 mPa·s at room temperature.

10. A method for preparing a diamond-reinforced alumina paste suitable for DLP printing according to claim 7, characterized in that: The ball milling process is performed at a speed of 200-500 rpm for 4-12 hours; the vacuum degree during vacuum stirring is 10. -1 Pa-10 -3 Pa, rotation speed 50-500 rpm, time 2-10 min; vacuum degree in the vacuum homogenizer is 10 -1 Pa-10 -3 Pa, speed 800-2000 rpm, time 1-5 min.

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