Preparation process of diamond / zirconium oxide composite ceramic suitable for photocuring molding
By preparing a ternary composite slurry of zirconia-diamond-photocurable resin and combining it with fluid dynamics optimization, the problems of insufficient wear resistance and thermal conductivity of porous zirconia ceramics were solved, achieving high-precision photocurable printing and improved fluid performance, making it suitable for high-efficiency fluid handling scenarios.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUPERHARD MATERIALS IND TECHNOLOGY RESEARCH INSTITUTE
- Filing Date
- 2026-01-27
- Publication Date
- 2026-04-28
AI Technical Summary
Existing porous zirconia ceramics suffer from poor wear resistance and low thermal conductivity in high-wear conditions and thermal management scenarios. Furthermore, the zirconia slurry for photopolymerization printing has issues such as contradictions between solid content and rheological properties, poor diamond dispersion, and lack of optimization of structural fluid properties, leading to difficulties in printing and uneven performance.
High-performance porous composite ceramics were prepared by using a ternary system of zirconia-diamond-photocurable resin composite slurry, which was pre-dispersed by ball milling, vacuum stirring and vacuum homogenization, combined with photocurable printing and hydrodynamic optimization. Modifiers were used to improve the interfacial compatibility between diamond and zirconia, and pore shape and pore size were optimized by CFD simulation.
It achieves uniform dispersion of diamond particles with high solid content, improves the wear resistance and thermal conductivity of composite ceramics, reduces fluid resistance, and improves mass transfer efficiency, making it suitable for high-precision photopolymerization printing and the fabrication of complex structural parts.
Smart Images
Figure CN121930009A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the interdisciplinary field of additive manufacturing and advanced ceramic materials, and specifically relates to a preparation process for diamond / zirconia composite ceramics suitable for photocuring. Background Technology
[0002] Zirconia ceramics are widely used in mechanical manufacturing, medical, and chemical industries due to their excellent mechanical strength, good chemical stability, and biocompatibility. Among them, porous zirconia ceramics, with their high throughput and low energy consumption characteristics brought by the three-dimensional interconnected pore structure, have greater advantages in fluid mass transfer-related fields (such as reactor carriers and filter elements). However, traditional porous zirconia ceramics have drawbacks such as poor wear resistance and low thermal conductivity, which can easily lead to structural failure or insufficient heat transfer efficiency in high-wear conditions (such as filtration of fluids containing solid particles) or scenarios requiring thermal management (such as high-temperature reactors).
[0003] Introducing diamond particles into a zirconia ceramic matrix can significantly improve the wear resistance and thermal conductivity of composite ceramics by taking advantage of diamond's high hardness (HV≥100GPa) and high thermal conductivity (2000-2500W / (m·K)). However, the poor interfacial compatibility between diamond and zirconia makes them prone to agglomeration in the slurry, leading to difficulties in printing and uneven final performance.
[0004] Photopolymerization technology, as a core branch of photopolymer additive manufacturing, possesses micron-level forming precision and high efficiency in surface exposure, making it an ideal technology for fabricating complex porous ceramic structures. However, existing zirconia pastes suitable for photopolymerization printing have the following problems: The contradiction between solid content and rheological properties: In order to ensure the leveling of printing, the solid content of the slurry is mostly below 70%, which leads to insufficient density of ceramics after sintering and a decrease in mechanical properties; if the solid content is increased, the viscosity will increase sharply due to uneven particle dispersion, which cannot meet the interlayer spreading requirements.
[0005] Diamond has poor dispersibility: The surface of diamond is inert and has weak interfacial bonding with zirconia particles and photocurable resin. Direct addition can easily form agglomerates, which not only affects printing accuracy but also produces interfacial defects after sintering, reducing the strength of composite ceramics.
[0006] Lack of optimization of structural fluid performance: Existing porous ceramic structure designs rely heavily on experience and do not incorporate systematic parameter optimization based on fluid dynamics characteristics. This leads to problems such as vortices and local high pressure within the pores, increasing fluid resistance and reducing mass transfer efficiency.
[0007] Therefore, developing a diamond / zirconia composite slurry that balances high solids content and good dispersibility, combined with photopolymerization printing technology and fluid dynamics optimization design, to prepare high-performance porous composite ceramics has become the key to solving the above problems. Summary of the Invention
[0008] The purpose of this invention is to address the shortcomings of the prior art by providing a preparation process for diamond / zirconia composite ceramics suitable for photocuring, which combines high solids content and good dispersibility in the diamond / zirconia composite slurry with photocuring printing technology and fluid dynamics optimization design to prepare high-performance porous composite ceramics.
[0009] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A preparation process for diamond / zirconia composite ceramics suitable for photocuring includes composite slurry preparation, photocuring printing, debinding and sintering, and hydrodynamic optimization. The composite slurry adopts a ternary system of "zirconia-diamond-photocurable resin" and is prepared by a three-step method of "ball milling pre-dispersion-vacuum stirring-vacuum homogenization". The preparation process steps are as follows: (1) Raw material selection Zirconia powder with a mass percentage of 62%-75%: Zirconia powder with a median particle size D50 of 1.2-8.0 μm and a purity of ≥99.5% was selected, and yttrium oxide stabilizer was added to the zirconia powder; 3%-7% diamond particles: Micron-sized diamonds with a particle size of 0.5-4.5μm are selected, modified with a modifier, the amount of which is 1.0%-2.5% of the diamond mass, and hydroxyl or epoxy groups are introduced on the diamond surface through hydrolysis. 15%-25% UV-curable resin system: The process employs a photosensitive prepolymer, a reactive diluent, and a photoinitiator. The photosensitive prepolymer provides the curing framework, the reactive diluent adjusts the viscosity, and the photoinitiator ensures rapid curing under ultraviolet light. 0.8%-2.5% dispersant: By combining amino acid ester copolymers with amphoteric polymers, steric hindrance and charge repulsion effects are utilized to suppress particle aggregation; 0.2%-1.2% of additives: A combination of silicone defoamer and acrylate leveling agent is used to eliminate air bubbles generated during slurry preparation. (2) Ball milling pre-dispersion Modified diamond, zirconium oxide powder and anhydrous ethanol are added to a ball mill jar. The ball milling particle size is 5-10 mm and the ball-to-particle ratio is 4:1-6:1. The ball milling is carried out to achieve preliminary particle dispersion. (3) Vacuum stirring Mix the photosensitive prepolymer, reactive diluent, photoinitiator and additives in a ratio of 40~55:40~50:1~2:2~4, and place them in a vacuum mixer to stir to ensure that the resin system is uniform. (4) Vacuum homogenization The ball-milled powder slurry is mixed with the resin system in step (3), a dispersant is added, and the mixture is processed in a vacuum homogenizer to obtain a composite slurry; (5) 3D model design A 3D interconnected hole model derived from face-centered cubic was built using SolidWorks. The model size is a 20-50mm cube and includes two sets of structures: a hole diameter gradient group and a hole shape topology group. Printing parameters were set. (6) Simulation model construction and optimization of fluid dynamics Import the three-dimensional interconnected hole model designed in step (5) into ANSYS, extract the real fluid domain through Boolean difference set operation, use structured mesh generation, optimize the fluid performance of the porous structure, and screen the flow field structure; (7) Photopolymerization printing Based on the optimized flow field structure in steps (5) and (6), the composite slurry obtained in step (4) is introduced into the photopolymer printer, the printing parameters are set and photopolymer printing is performed. After printing, the uncured slurry on the surface of the green body is cleaned with isopropanol or alcohol and then dried for later use. (8) Degreasing and sintering Degreasing process: Place the green body in a tube furnace, heat it to 200~300℃ and hold it for 1~2 hours to remove low-boiling-point organic matter, then continue to heat it to 500~550℃ and hold it for 2~3 hours to remove resin and dispersant, and high-purity argon gas is introduced for protection throughout the process. Sintering process: After degreasing, the temperature is raised to 1550~1620℃ and held for 3~5 hours. Then, it is cooled to room temperature in the furnace and sintered in a high-purity argon atmosphere to obtain diamond / zirconia composite ceramics.
[0010] The modifier is silane coupled with KH-560, stearic acid, or maleic anhydride.
[0011] In step (1), the photosensitive prepolymer is bisphenol A diacrylate or epoxy acrylate; the reactive diluent is 1,6-hexanediol diacrylate and trimethylolpropane triacrylate in a mass ratio of 3:2; and the photoinitiator is TPO and 819 in a mass ratio of 1:1.
[0012] In step (3), the vacuum degree of the vacuum mixer is 10. -1 ~10 -3 Pa, rotation speed 100~300rpm, time 3~8min; In step (4), the vacuum degree of the vacuum homogenizer is 10. -1 ~10 -3 Pa, rotation speed 800~1500rpm, time 2~6min.
[0013] In step (5), the aperture gradient group is a circular through hole with an aperture of 2~4mm.
[0014] In step (5), each face of the hole topology group is provided with multiple through holes, and the hole shape is set as a multi-hole through hole structure, including petal shape, hexagon, square, heart shape or four-pointed star shape.
[0015] In step (7), the printing parameters are set to a layer thickness of 10-50 μm and an ultraviolet light power of 30-60 mW / cm. 2 Exposure time is 2-5 seconds per layer, and leveling time is 30-120 seconds.
[0016] In step (6), the flow field structure boundary conditions and solution settings are as follows: The working fluid is air, the inlet velocity is 1 m / s, the outlet pressure is 0 Pa, and there is no slippage on the wall. A pressure-based solver was selected, the SSTk-omega model was used to simulate turbulence, and the SIMPLE algorithm was used to couple pressure and velocity, iterating until the residuals were <10. -6 .
[0017] The beneficial effects of this invention are: (1) This invention discloses a preparation process for diamond / zirconia composite ceramics suitable for photocuring. By modifying the surface of diamond particles, designing the composite slurry formulation, combining photocuring and debinding sintering, and optimizing the three-dimensional interconnected structure with specific pore shape / pore size and fluid dynamics simulation, a diamond / zirconia composite ceramic with high mechanical strength, excellent wear resistance and thermal conductivity, and low flow resistance and mass transfer efficiency is prepared. The solid content of the composite slurry reaches 72%-78%, and the process is completed in 25s. -1 With a viscosity of 1.8-3.0 Pa·s at shear rates, it meets the interlayer spreading requirements of photopolymer printing while ensuring the density of the composite ceramic after sintering, making it suitable for high-precision forming of 10-50 μm layer thicknesses in photopolymer printing.
[0018] (2) Improved performance of composite ceramics: Diamond particles are uniformly dispersed in the zirconia matrix, which makes the flexural strength of the composite ceramics reach 380-450 MPa, which is 20%-35% higher than that of pure zirconia ceramics; the thermal conductivity reaches 45-60 W / (m·K), which is 40%-60% higher; and the wear resistance is significantly better than that of traditional porous zirconia ceramics, with a wear rate ≤5×10 -6 mm 3 / (N·m), through diamond surface modification and composite dispersion process, the problem of diamond agglomeration was solved and the interfacial bonding force between diamond and zirconia matrix was improved.
[0019] (3) Structural fluid performance optimization: The pore size and shape of the printed diamond / zirconia composite ceramic porous structure are optimized by combining CFD simulation to reduce fluid resistance, improve flow field uniformity, and achieve synergistic optimization of "structure-performance-function"; the hexagonal / square pore shape and pore size of 2.5-3.5mm selected by CFD simulation have a 15%-22% lower pressure drop than the traditional circular pore structure under the same working conditions, a flow field uniformity of more than 25% and a mass transfer efficiency of 30%-45%, which is suitable for high-efficiency fluid processing scenarios.
[0020] (4) Strong process compatibility: It is compatible with mainstream photopolymerization printing equipment and can prepare structural parts with internal holes, thin walls and complex through holes. Moreover, the debinding and sintering process is stable, which broadens the application boundaries of porous composite ceramics. Attached Figure Description
[0021] Figure 1 This is a process flow diagram of the present invention; Figure 2 These are schematic diagrams of the microstructure of diamond / zirconia composite ceramics before and after sintering ((e) shows the microstructure before sintering, and (f) shows the microstructure after sintering). Figure 3 This is a physical image of a hexagonal hole-shaped diamond / zirconia composite ceramic sample printed using photopolymerization. Figure 4 These are CFD simulation pressure contour images of different pore structures; Table 1 shows a comparison of parameters for each embodiment. 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] This invention provides a preparation process for diamond / zirconia composite ceramics suitable for photocuring, such as... Figures 1 to 4 As shown.
[0024] A preparation process for diamond / zirconia composite ceramics suitable for photocuring includes composite slurry preparation, photocuring printing, debinding and sintering, and hydrodynamic optimization. The composite slurry adopts a ternary system of "zirconia-diamond-photocurable resin" and is prepared by a three-step method of "ball milling pre-dispersion-vacuum stirring-vacuum homogenization". The preparation process steps are as follows: (1) Raw material selection Zirconia powder: Zirconia powder with a median particle size D50 of 1.2-8.0 μm and a purity of ≥99.5% was selected, and 3 mol% yttrium oxide stabilizer was added to the zirconia powder to ensure the formation of a stable tetragonal zirconia matrix after sintering, thereby improving the mechanical properties of the ceramic. Diamond particles: Micron-sized diamonds with a particle size of 0.5-4.5μm are selected and modified by silane coupling with KH-560, or by grafting with stearic acid or maleic anhydride. The amount of modifier is 1.0%-2.5% of the diamond mass. Hydroxyl groups (-OH) or epoxy groups (-COC-) are introduced on the diamond surface through hydrolysis to enhance the interfacial compatibility with zirconium oxide and resin. UV-curable resin system: The process employs a photosensitive prepolymer, a reactive diluent, and a photoinitiator. The photosensitive prepolymer provides the curing framework, the reactive diluent adjusts the viscosity, and the photoinitiator ensures rapid curing under ultraviolet light. Preferably, the photosensitive prepolymer can be bisphenol A diacrylate / epoxy acrylate, the reactive diluent is a mixture of 1,6-hexanediol diacrylate and trimethylolpropane triacrylate in a 3:2 mass ratio, and the photoinitiator is a mixture of TPO and 819 in a 1:1 mass ratio. The photosensitive prepolymer provides the curing framework, the reactive diluent adjusts the viscosity, and the photoinitiator ensures rapid curing under ultraviolet light. Dispersant: By combining amino acid ester copolymers with amphoteric polymers, and utilizing steric hindrance and charge repulsion effects, particle agglomeration can be inhibited. Solsperse-20000 and KOS163 can be combined. Additives: The use of silicone defoamers, such as BYK-066N, combined with acrylate leveling agents, such as BYK-333, eliminates air bubbles generated during slurry preparation and improves the smoothness between printing layers.
[0025] (2) Ball milling pre-dispersion Modified diamond and zirconium oxide powders were added to an agate ball mill jar with an anhydrous ethanol at a solvent-to-powder mass ratio of 1:1.5. The agate balls had a particle size of 5-10 mm, a ball-to-powder ratio of 5:1, and the milling speed was 400 rpm for 8 hours to achieve initial particle dispersion.
[0026] (3) Vacuum stirring The photosensitive prepolymer, reactive diluent, photoinitiator, and additives were mixed in proportion and stirred in a vacuum mixer at a vacuum degree of 10. -2 Stir at 50-200 rpm for 5 minutes to ensure the resin system is homogeneous.
[0027] (4) Vacuum homogenization The ball-milled powder slurry is mixed with the resin system from step (3), a dispersant is added, and the mixture is processed in a vacuum homogenizer for 4 minutes at a vacuum degree of 10. -2 Pa, rotation speed 800-1500 rpm, to obtain composite slurry.
[0028] (5) 3D model design A 3D interconnected via model derived from Face-Centered Cube (FCC) was built using SolidWorks. The model size is a 20-50mm cube and includes two sets of structures: a aperture gradient group and a aperture topology group. Printing parameters were set. Among them, the aperture gradient group consists of circular through holes with apertures of 2, 2.5, 3, 3.5, and 4 mm, respectively, which are used to analyze the influence of aperture on fluid resistance. Each face of the orifice topology group has 7×7 through holes with a reference diameter of 2mm. The orifice shapes include petal, hexagon, square, heart, or quadrangular star shapes, which are used to screen the optimal flow field structure.
[0029] (6) Simulation model construction and optimization of fluid dynamics Import the three-dimensional interconnected through-hole model designed in step (5) into ANSYS, extract the real fluid domain through Boolean difference set operation, adopt structured mesh generation, refine the mesh at the corner of the channel, the minimum mesh size is 5μm, the mesh distortion rate is ≤0.3, optimize the fluid performance of the porous structure, and screen the flow field structure. The flow field structure boundary conditions and solution settings are as follows: The working fluid is air, with a density of 1.29 kg / m³ at room temperature. 3 Kinematic viscosity 1.8 × 10⁻⁶ -5 Pa·s, inlet velocity 1 m / s, outlet pressure 0 Pa, no wall slippage; A pressure-based solver was selected, employing the SST k-omega model and the SIMPLE algorithm to simulate the flow field under conditions of inlet velocity 0.5-2 m / s and outlet pressure 0 Pa. The total pressure drop, velocity distribution, and vortex region proportion were analyzed. The SIMPLE algorithm coupled pressure and velocity, iterating until the residuals were <10. -6 The optimal structure with hexagonal or square holes and a diameter of 2.5-3.5mm was selected. Optimization and screening: Analysis of the total pressure drop, velocity distribution, and vortex ratio of different structures showed that the hexagonal and square apertures, due to their smooth boundaries and lack of obvious vortices, had total pressure drops of 680 Pa and 720 Pa, respectively. Compared with the four-cornered star aperture (1050 Pa), the hexagonal aperture reduced pressure by 35%-38%, and the square aperture reduced pressure by 31%-33%. When the aperture was 2.5-3.5 mm, the flow field uniformity was the best, the standard deviation of the cross-sectional velocity was ≤0.25 m / s, and the mass transfer efficiency was the highest.
[0030] (7) Photopolymerization printing Based on the optimized flow field structure in steps (5) and (6), a photopolymerization printer was used to set the printing parameters and the composite slurry obtained in step (4) was photopolymerized and printed. After printing, the uncured slurry on the surface of the green body was cleaned with isopropanol or alcohol and dried for later use. Using a MicroArch® S240 UV printer, the printing parameters were set to a layer thickness of 10-50μm and a UV light power of 30-60mW / cm. 2 Exposure time is 2-5 seconds per layer, and leveling time is 30-120 seconds.
[0031] (8) Degreasing and sintering Degreasing process: The green body is placed in a GSL-1700X tube furnace and heated to 200~300℃ at a rate of 0.5-5℃ / min and held for 1~2 hours to remove low-boiling-point organic matter. Then, the temperature is further increased to 520℃ at a rate of 0.5-5℃ / min and held for 2~3 hours to remove resin and dispersant. High-purity argon gas is introduced throughout the process for protection. Sintering process: After degreasing, the temperature is raised to 1550~1620℃ at a rate of 0.5-5℃ / min and held for 2~4h. Then, the temperature is cooled to room temperature in the furnace. Sintering under a high-purity argon atmosphere can avoid the reaction between diamond and oxygen to generate CO / CO2, thus obtaining diamond / zirconia composite ceramics and ensuring the stability of the composite phase.
[0032] The following description, in conjunction with specific embodiments, provides further details: Example 1
[0033] Preparation of composite slurry Raw material ratio (mass percentage): 65% zirconia powder (D50=1.735μm, containing 3mol% yttrium oxide), 7% modified diamond particles (particle size 1μm, KH-560 modification: diamond and modifier added to anhydrous ethanol, stirred at 60℃ for 3h, vacuum dried and passed through a 300-mesh sieve, modifier dosage 1.8%), 25% photocurable resin system (including photosensitive prepolymer: 5 parts bisphenol A diacrylate; reactive diluent: 3 parts 1,6-hexanediol diacrylate + 2 parts trimethylolpropane triacrylate; photoinitiator: 0.8 parts TPO + 1.2 parts 819), 2% dispersant (Solsperse-20000:KOS163=1:2), 1% additives (BYK-066N:BYK-333=1:3).
[0034] Dispersion process: Ball milling (using anhydrous ethanol as solvent, ball-to-material ratio 5:1, speed 400 rpm, 8 h) → vacuum stirring (10 -2 Pa, 200 rpm, 5 min) → Vacuum homogenization (10 -2The viscosity of the resulting slurry was 2.2 Pa·s (25 s⁻¹) at 1500 rpm for 4 min. -1 ), aggregate particle size ≤4μm.
[0035] Photopolymer printing Model: 20mm×20mm×20mm cube, hexagonal aperture (7×7 apertures / face, aperture diameter 2.5mm); Parameters: layer thickness 25μm, UV power 50mW / cm² 2 Exposure time 3s / layer, leveling time 60s, printing green body size error ±0.5%.
[0036] Degreasing and sintering: Degreasing: Heating to 200℃ at 1℃ / min (1h) → Heating to 520℃ at 0.5℃ / min (2.5h) under high-purity argon atmosphere; Sintering: Heating to 1600℃ at 2℃ / min (3h) and cooling with the furnace to obtain composite ceramics.
[0037] Performance testing: XRD analysis revealed that the phase composition consisted of pure tetragonal zirconia and diamond, with no impurities. The flexural strength was 420 MPa, the thermal conductivity was 52 W / (m·K), and the wear rate was 3.2 × 10⁻⁶. -6 mm 3 / (N·m); Fluid performance: CFD simulation showed a total pressure drop of 680Pa (inlet velocity 1m / s), flow field uniformity of 92%, and experimental test showed a flux increase of 38% compared to the traditional circular orifice structure. Example 2
[0038] Preparation of composite slurry: The raw material ratio is the same as in Example 1, except that the diamond particle size is changed to 2.5 μm (KH-560 modified, modifier dosage 1.8%); the dispersion process (ball milling 400 rpm × 8 h → vacuum stirring 200 rpm × 5 min → vacuum homogenization 1500 rpm × 4 min) remains unchanged, and the slurry viscosity is 2.5 Pa·s (25 s). -1 ), aggregate particle size ≤ 4.5 μm.
[0039] Photopolymerization printing: Model (20mm cube, 7×7 hexagonal holes / face, 2.5mm hole diameter), parameters (layer thickness 25μm, UV power 50mW / cm²). 2 Exposure for 3 seconds per layer, leveling for 60 seconds), same as in Example 1.
[0040] Degreasing and sintering: Same as in Example 1, i.e., degreasing → sintering at 1600℃ for 3 hours.
[0041] Performance testing: The phase composition is tetragonal zirconia + diamond; the flexural strength is 400 MPa, the thermal conductivity is 48 W / (m·K), and the wear rate is 3.8 × 10⁻⁶. -6 mm 3 / (N·m); CFD total pressure drop 690Pa, flow field uniformity 90%, flux increased by 35% compared with traditional circular orifice. Example 3
[0042] Preparation of composite slurry: The raw material ratio is the same as in Example 1, except that the D50 of the zirconia powder is changed to 4.0 μm (containing 3 mol% yttrium oxide); the dispersion process remains unchanged, and the slurry viscosity is 2.4 Pa·s (25 s). -1 ), aggregate particle size ≤ 4.2 μm.
[0043] Photopolymerization printing: The model and parameters are the same as in Example 1.
[0044] Degreasing and sintering: Same as in Example 1.
[0045] Performance testing: The phase composition is tetragonal zirconia + diamond; the flexural strength is 390 MPa, the thermal conductivity is 46 W / (m·K), and the wear rate is 4.1 × 10⁻⁶. -6 mm 3 / (N·m); CFD total pressure drop 700Pa, flow field uniformity 88%, flux increased by 33% compared to traditional circular orifice. Example 4
[0046] Preparation of composite slurry: The raw material ratio is the same as in Example 1, except that the dispersant is changed to Solsperse-20000:KOS163=1:1; the dispersion process remains unchanged, and the slurry viscosity is 2.6 Pa·s (25 s). -1 ), aggregate particle size ≤ 4.8 μm.
[0047] Photopolymerization printing: The model and parameters are the same as in Example 1.
[0048] Degreasing and sintering: Same as in Example 1.
[0049] Performance testing: The phase composition is tetragonal zirconia + diamond; flexural strength is 385 MPa, thermal conductivity is 45 W / (m·K), and wear rate is 4.3 × 10⁻⁶. -6 mm 3 / (N·m); CFD total pressure drop 710Pa, flow field uniformity 87%, flux increased by 32% compared to traditional circular orifice. Example 5
[0050] Preparation of composite slurry: Same as in Example 1 (slurry viscosity 2.2 Pa·s, agglomerate particle size ≤ 4 μm).
[0051] Photopolymerization printing: The model and parameters are the same as in Example 1.
[0052] Degreasing and sintering: The degreasing process is the same as in Example 1, but the sintering is changed to a temperature increase of 2℃ / min to 1550℃ (holding for 3h).
[0053] Performance testing: The phase composition is tetragonal zirconia + diamond; bending strength is 380 MPa, thermal conductivity is 44 W / (m·K), and wear rate is 4.5 × 10⁻⁶. -6 mm 3 / (N·m); CFD total pressure drop 720Pa, flow field uniformity 86%, flux increased by 30% compared to traditional circular orifice. Comparative Example 1
[0054] Compared with Example 1, the preparation of the composite slurry with unmodified diamond was the same except that the diamond particles were not surface modified; the results showed that the slurry viscosity was 3.8 Pa·s (25 s⁻¹). -1 The aggregate particle size is ≥15μm, and interlayer delamination occurs during printing; the sintered composite ceramic has a flexural strength of 280MPa, a thermal conductivity of 30W / (m·K), and a wear rate of 1.8×10⁻⁶. -5 mm 3 / (N·m), the performance is significantly inferior to that of Example 1. Comparative Example 2
[0055] Compared to Example 1, the printed model has a four-cornered star-shaped aperture with a diameter of 2.5 mm, while all other parameters remain the same. Results: CFD simulation showed a total pressure drop of 1050 Pa (inlet velocity 1 m / s), flow field uniformity of 65%, and experimental flux reduction of 35% compared to Example 1, verifying the necessity of aperture optimization. Parameters for each example are shown in Table 1 below.
[0056] Table 1. Parameter Comparison of Various Embodiments
[0057] If this patent uses terms such as "first" and "second" to define components, those skilled in the art should know that the use of "first" and "second" is merely for the convenience of describing the invention and simplifying the description, and the above terms have no special meaning.
[0058] 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.
[0059] 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 preparation process for diamond / zirconia composite ceramics suitable for photocuring, characterized in that, The process includes composite slurry preparation, photopolymerization printing, debinding and sintering, and hydrodynamic optimization. The composite slurry adopts a ternary system of "zirconia-diamond-photopolymerized resin" and is prepared using a three-step method of "ball milling pre-dispersion-vacuum stirring-vacuum homogenization". The preparation process steps are as follows: (1) Raw material selection Zirconia powder with a mass percentage of 62%-75%: Zirconia powder with a median particle size D50 of 1.2-8.0 μm and a purity of ≥99.5% was selected, and yttrium oxide stabilizer was added to the zirconia powder; 3%-7% diamond particles: Micron-sized diamonds with a particle size of 0.5-4.5μm are selected, modified with a modifier, the amount of which is 1.0%-2.5% of the diamond mass, and hydroxyl or epoxy groups are introduced on the diamond surface through hydrolysis. 15%-25% UV-curable resin system: The process employs a photosensitive prepolymer, a reactive diluent, and a photoinitiator. The photosensitive prepolymer provides the curing framework, the reactive diluent adjusts the viscosity, and the photoinitiator ensures rapid curing under ultraviolet light. 0.8%-2.5% dispersant: By combining amino acid ester copolymers with amphoteric polymers, steric hindrance and charge repulsion effects are utilized to suppress particle aggregation; 0.2%-1.2% of additives: A combination of silicone defoamer and acrylate leveling agent is used to eliminate air bubbles generated during slurry preparation. (2) Ball milling pre-dispersion Modified diamond, zirconium oxide powder and anhydrous ethanol are added to a ball mill jar. The ball milling particle size is 5-10 mm and the ball-to-particle ratio is 4:1-6:
1. The ball milling is carried out to achieve preliminary particle dispersion. (3) Vacuum stirring Mix the photosensitive prepolymer, reactive diluent, photoinitiator and additives in a ratio of 40~55:40~50:1~2:2~4, and place them in a vacuum mixer to stir to ensure that the resin system is uniform. (4) Vacuum homogenization The ball-milled powder slurry is mixed with the resin system in step (3), a dispersant is added, and the mixture is processed in a vacuum homogenizer to obtain a composite slurry; (5) 3D model design A 3D interconnected hole model derived from face-centered cubic was built using SolidWorks. The model size is a 20-50mm cube and includes two sets of structures: a hole diameter gradient group and a hole shape topology group. Printing parameters were set. (6) Simulation model construction and optimization of fluid dynamics Import the three-dimensional interconnected hole model designed in step (5) into ANSYS, extract the real fluid domain through Boolean difference set operation, use structured mesh generation, optimize the fluid performance of the porous structure, and screen the flow field structure; (7) Photopolymerization printing Based on the optimized flow field structure in steps (5) and (6), the composite slurry obtained in step (4) is introduced into the photopolymer printer, the printing parameters are set and photopolymer printing is performed. After printing, the uncured slurry on the surface of the green body is cleaned with isopropanol or alcohol and then dried for later use. (8) Degreasing and sintering Degreasing process: Place the green body in a tube furnace, heat it to 200~300℃ and hold it for 1~2 hours to remove low-boiling-point organic matter, then continue to heat it to 500~550℃ and hold it for 2~3 hours to remove resin and dispersant, and high-purity argon gas is introduced for protection throughout the process. Sintering process: After degreasing, the temperature is raised to 1550~1620℃ and held for 3~5 hours. Then, it is cooled to room temperature in the furnace and sintered in a high-purity argon atmosphere to obtain diamond / zirconia composite ceramics.
2. The preparation process of diamond / zirconia composite ceramics suitable for photocuring as described in claim 1, characterized in that: The modifier is silane coupled with KH-560, stearic acid, or maleic anhydride.
3. The preparation process of diamond / zirconia composite ceramics suitable for photocuring as described in claim 1, characterized in that: In step (1), the photosensitive prepolymer is bisphenol A diacrylate or epoxy acrylate; the reactive diluent is 1,6-hexanediol diacrylate and trimethylolpropane triacrylate in a mass ratio of 3:2; and the photoinitiator is TPO and 819 in a mass ratio of 1:
1.
4. The preparation process of diamond / zirconia composite ceramics suitable for photocuring as described in claim 1, characterized in that: In step (3), the vacuum degree of the vacuum mixer is 10. -1 ~10 -3 Pa, rotation speed 100~300rpm, time 3~8min; In step (4), the vacuum degree of the vacuum homogenizer is 10. -1 ~10 -3 Pa, rotation speed 800~1500rpm, time 2~6min.
5. The preparation process of diamond / zirconia composite ceramics suitable for photocuring as described in claim 1, characterized in that: In step (5), the aperture gradient group is a circular through hole with an aperture of 2~4mm.
6. The preparation process of diamond / zirconia composite ceramics suitable for photocuring as described in claim 1, characterized in that: In step (5), each face of the hole topology group is provided with multiple through holes, and the hole shape is set as a multi-hole through hole structure, including petal shape, hexagon, square, heart shape or four-pointed star shape.
7. The preparation process of diamond / zirconia composite ceramics suitable for photocuring as described in claim 1, characterized in that: In step (7), the printing parameters are set to a layer thickness of 10-50 μm and an ultraviolet light power of 30-60 mW / cm. 2 Exposure time is 2-5 seconds per layer, and leveling time is 30-120 seconds.
8. The preparation process of diamond / zirconia composite ceramics suitable for photocuring as described in claim 1, characterized in that: In step (6), the flow field structure boundary conditions and solution settings are as follows: The working fluid is air, the inlet velocity is 1 m / s, the outlet pressure is 0 Pa, and there is no slippage on the wall. A pressure-based solver was selected, the SSTk-omega model was used to simulate turbulence, and the SIMPLE algorithm was used to couple pressure and velocity, iterating until the residuals were <10. -6 .