Highly thermally conductive ceramic material and additive manufacturing method thereof

Abstract

This invention discloses a high thermal conductivity ceramic material and its additive manufacturing method. The method includes the following steps: ball milling and mixing aluminum nitride, a sintering aid, a first wetting and dispersing agent, and an organic solvent, followed by drying and sieving to obtain modified aluminum nitride powder; vacuum ball milling and mixing a photocurable prepolymer and a photocurable monomer to obtain a photocurable premix; vacuum ball milling and mixing the modified aluminum nitride powder, the photocurable premix, a second wetting and dispersing agent, a plasticizer, and a photoinitiator under light-protected conditions to obtain a photocurable ceramic slurry; layer-by-layer printing and curing using the photocurable ceramic slurry to obtain an aluminum nitride ceramic green body; and sequentially pyrolyzing, degreasing, and sintering the aluminum nitride ceramic green body to obtain a high thermal conductivity ceramic material. The aluminum nitride ceramic green body prepared by this invention has strong interlayer bonding, high solid content, and high green body precision, and its thermal conductivity after sintering is higher than 200 W / m·K. The method of this invention has simple process steps.

Description

Technical Field

[0001] This invention relates to the field of aluminum nitride ceramics technology, and more particularly to a high thermal conductivity ceramic material and its additive manufacturing method. Background Technology

[0002] Aluminum nitride (AlN) ceramics possess high thermal conductivity, excellent dielectric properties, low coefficient of thermal expansion, and good insulation properties, making them widely used in high-power integrated circuits, electronic devices, optics, and intelligent manufacturing, where heat dissipation is crucial. To maximize the heat dissipation capacity of AlN ceramic components, they can be designed as heat sink structures with complex shapes or microchannels. Traditional molding methods such as dry pressing and isostatic pressing are suitable for preparing simple-shaped AlN ceramic materials, while tape casting is only suitable for preparing AlN substrates with a thickness of less than 1 mm. For complex-shaped parts, machining methods are costly and involve significant wear due to the high hardness and brittleness of AlN ceramics. Gel molding and thermal injection molding require molds, leading to long processing cycles and increased costs, thus limiting the development and application of high thermal conductivity AlN ceramics. Additive manufacturing (3D printing) utilizes the layer-by-layer principle, slicing a 3D model created by computer modeling software into layers of continuously stacked 2D models, and then manufacturing and stacking these layers to obtain a 3D solid. 3D printing boasts advantages such as high flexibility and mold-free operation, enabling the freeform shaping of parts and finding wide application in complex ceramic structures. Additive manufacturing technologies mainly include bond jetting (BJ), direct writing (DIW), layered solid fabrication (LOM), fused deposition modeling (FDM), selective laser melting (SLM), stereolithography (SLA), and surface photopolymerization (DLP). Among these, SLA and DLP both belong to photopolymerization (VPP), which involves mixing ceramic powder with photosensitive resin liquid and using photo-induced, layered photopolymerization to fabricate complex-shaped devices, showing great application potential in the additive manufacturing of functional ceramics.

[0003] High-solids-content, low-viscosity ceramic slurry is the primary challenge in photopolymer 3D printing of ceramics. High solids content helps increase the density of the green body and ceramic body, reduces sintering shrinkage, and minimizes crack formation; low viscosity facilitates uniform slurry coating during printing, resulting in a complete ceramic green body. Furthermore, good bonding strength between layers in 3D printing is essential to prevent delamination and warping, requiring a high single-layer curing thickness and optimized layer thickness. Due to the high refractive index and absorbance of aluminum nitride, ultraviolet light has difficulty penetrating the aluminum nitride slurry, resulting in low single-layer curing thickness. While increasing ultraviolet light power and exposure time can improve the single-layer curing depth to some extent, this is accompanied by an increase in over-curing width, reducing molding accuracy. To address the issue of low curing depth in aluminum nitride, researchers employed a powder coating technique, depositing Y(NO3)3 onto the surface of AlN powder. Through low-temperature (450℃) calcination and high-temperature (1500℃) nitrogen atmosphere treatment, yttrium aluminate (YAG) was formed on the aluminum nitride powder surface, reducing the absorbance of the aluminum nitride powder to 405nm ultraviolet light to 0.171, thereby increasing the curing depth of the slurry (Additive Manufacturing 74 (2023) 103732). This method requires pretreatment and calcination of the aluminum nitride powder, involving cumbersome steps and complex processes. Furthermore, the types of aluminum nitride sintering aids are limited to yttrium oxide. Patent CN 117776734 A discloses an aluminum nitride ceramic part and its forming method, which improves the curing depth of the slurry by grading three aluminum nitride powders of different particle sizes. Nanoscale aluminum nitride powder in graded powders has a high specific surface area and activity, easily adsorbing oxygen or water from the air, leading to an increase in oxygen content. The thermal conductivity of AlN ceramics is closely related to oxygen content, as oxygen replaces nitrogen to form aluminum vacancy defects, increasing phonon scattering. Furthermore, the second phase formed during sintering by the reaction of the oxide layer on the surface of aluminum nitride powder with sintering aids has a much lower thermal conductivity than aluminum nitride material, thus deteriorating the thermal conductivity of aluminum nitride ceramics. Larger particle sizes can increase the curing depth, but also increase the curing width, leading to a decrease in precision.

[0004] Therefore, there is an urgent need to provide an additive manufacturing method using high thermal conductivity aluminum nitride ceramics to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a high thermal conductivity ceramic material and its additive manufacturing method, which solves the technical problems in the prior art of using photopolymerization technology to prepare aluminum nitride ceramics, which makes it difficult to achieve both high curing depth and curing precision, and the prepared aluminum nitride ceramics have poor thermal conductivity.

[0006] In a first aspect, the present invention provides an additive manufacturing method for a high thermal conductivity ceramic material, comprising the following steps:

[0007] Aluminum nitride, sintering aid, first wetting and dispersing agent and organic solvent were ball-milled and mixed, then dried and sieved to obtain modified aluminum nitride powder;

[0008] The photocurable prepolymer and the photocurable monomer were mixed by vacuum ball milling to obtain the photocurable premix;

[0009] Under light-protected conditions, modified aluminum nitride powder, photocurable premix, second wetting and dispersing agent, plasticizer and photoinitiator are mixed by vacuum ball milling to obtain photocurable ceramic slurry;

[0010] Based on the three-dimensional model of the component, a light-curing ceramic slurry is used for layer-by-layer printing and curing to obtain an aluminum nitride ceramic preform;

[0011] Aluminum nitride ceramic blanks are sequentially pyrolyzed, degreased, and sintered to obtain high thermal conductivity ceramic materials.

[0012] In a second aspect, the present invention provides a high thermal conductivity ceramic material, which is obtained by the additive manufacturing method of the high thermal conductivity ceramic material provided in the first aspect of the present invention.

[0013] Compared with the prior art, the beneficial effects of the present invention include:

[0014] The aluminum nitride ceramic green body prepared by this invention has strong interlayer bonding, high solid content, and high green body precision (over-curing width less than 100 μm), and its thermal conductivity after sintering is higher than 200 W / m·K. The method of this invention has simple process steps. Attached Figure Description

[0015] Figure 1 It is the ultraviolet absorbance spectrum of aluminum nitride powder, wetting and dispersing agent and modified aluminum nitride powder obtained in step (1) of Example 1 of this invention;

[0016] Figure 2 This is a cross-sectional SEM image of the aluminum nitride ceramic blank obtained in step (4) of Embodiment 1 of the present invention;

[0017] Figure 3 This is an optical photograph of the high thermal conductivity ceramic material obtained in step (5) of Embodiment 1 of the present invention;

[0018] Figure 4 This is a SEM image of the aluminum nitride ceramic material obtained in step (5) of Comparative Example 4 of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] In a first aspect, the present invention provides an additive manufacturing method for a high thermal conductivity ceramic material, comprising the following steps:

[0021] S1. Aluminum nitride modification: Aluminum nitride, sintering aid, first wetting and dispersing agent and organic solvent are ball-milled and mixed, then dried and sieved to obtain modified aluminum nitride powder;

[0022] S2. Preparation of photocurable premix: The photocurable prepolymer and the photocurable monomer are mixed by vacuum ball milling to obtain the photocurable premix;

[0023] S3. Preparation of photocurable ceramic slurry: Under light-protected conditions, modified aluminum nitride powder, photocurable premix, second wetting and dispersing agent, plasticizer and photoinitiator are mixed by vacuum ball milling to obtain photocurable ceramic slurry;

[0024] S4, 3D printing: Based on the three-dimensional model of the component, a photocurable ceramic slurry is used for layer-by-layer printing and curing to obtain an aluminum nitride ceramic blank;

[0025] S5. Pyrolysis, Degreasing and Sintering: The aluminum nitride ceramic blank is first pyrolyzed in a protective atmosphere, then degreased in air, and finally sintered in a nitrogen atmosphere to obtain a high thermal conductivity ceramic material.

[0026] This invention adjusts the refractive index difference between aluminum nitride powder and resin by adding rare earth fluorides and oxides with low absorbance that also act as sintering aids, thereby reducing the absorbance of the powder and increasing the curing depth. The invention also employs phosphate ester wetting and dispersing agents, which not only achieve good dispersion of AlN powder and its miscibility with photosensitive resin, reducing slurry viscosity, but also possess a high refractive index, improving the overall performance of the slurry. The addition is done in two steps: one part is added during ball milling of the ceramic powder, adsorbing onto the powder surface and promoting uniform dispersion of ceramic powders of different densities through electrostatic steric hindrance, reducing the absorbance and thus increasing the curing depth; the other part is added during the preparation of the photocurable ceramic slurry, achieving effective wetting and dispersion of the solid powder in the resin, reducing the viscosity of the photocurable slurry. Furthermore, the addition of plasticizers to the photocurable ceramic slurry improves printing accuracy and solves the problem of microcracks easily generated during degreasing of the preform. This invention first pyrolyzes the aluminum nitride ceramic green body in a protective atmosphere, ensuring uniform pyrolysis of the photocurable resin, reducing the generation of large amounts of gas, and avoiding defects such as cracking caused by excessively rapid decomposition of the photosensitive resin due to direct thermal oxidation and decomposition in air. Subsequently, debinding in air reduces carbon residue generated by thermal pyrolysis, preventing excessive carbon residue from hindering subsequent densification sintering. Finally, sintering is performed in a nitrogen atmosphere to prevent oxidation of aluminum nitride and ensure chemical stability. The aluminum nitride ceramic green body prepared by this invention exhibits strong interlayer bonding, high solid content, and high green body precision (over-curing width less than 100 μm), with a thermal conductivity exceeding 200 W / m·K after sintering. The method of this invention has simple process steps.

[0027] In this embodiment, in step S1, the aluminum nitride is micron-sized aluminum nitride with an average particle size of 1-2 μm.

[0028] In this embodiment, in step S1, the sintering aid is a combination of at least one of samarium fluoride and samarium oxide with yttrium fluoride, and its addition amount is 5% to 7% of the mass of aluminum nitride.

[0029] Preferably, yttrium fluoride accounts for 25% to 60% of the total mass of the sintering aid.

[0030] In this embodiment, in step S1, the average particle size of the sintering aid is 1-2 μm.

[0031] In this embodiment, in step S1, the first wetting and dispersing agent is a phosphate ester wetting and dispersing agent, and its addition amount is 0.5% to 1% of the total mass of aluminum nitride and sintering aid.

[0032] In some specific embodiments of the present invention, the first wetting and dispersing agent is BYK110.

[0033] In this embodiment, in step S1, the organic solvent is ethanol, and its addition amount is 70%~80% of the total mass of aluminum nitride and sintering aid.

[0034] In this embodiment, in step S1, the ball milling method is planetary ball milling, the ball milling time is 5 to 10 hours, the ball milling speed is 300 to 400 rpm, the ball milling medium is zirconia balls with a diameter of 2 to 10 mm, and the mass ratio of zirconia balls to aluminum nitride is (3 to 5): 1.

[0035] In this embodiment, in step S1, the mesh size of the sieve is 100~200 mesh.

[0036] In this embodiment, in step S2, the photocurable prepolymer is a low-viscosity (approximately 350 mPa·s) difunctional aliphatic polyurethane acrylate. By using a low-viscosity difunctional aliphatic polyurethane acrylate as the photocurable prepolymer, this invention effectively reduces the viscosity of the photosensitive resin, resulting in a cured monolayer with good toughness and strength, reducing the generation of multilayer stress, and preventing bending deformation of the preform.

[0037] In this embodiment, in step S2, the photocurable monomer is a combination of o-phenylphenoxyethyl acrylate (OPPEA), 1,6-hexanediol diacrylate (HDDA), and pentaerythritol tetraacrylate ethoxylate (PPTTA). This invention improves the curing depth by introducing the high-refractive-index monofunctional monomer o-phenylphenoxyethyl acrylate (1.576), which increases the refractive index of the photosensitive resin. It also improves the reactivity and reduces viscosity and volume shrinkage by introducing the difunctional monomer 1,6-hexanediol diacrylate. Finally, it increases the curing crosslinking density and further enhances the preform strength by introducing the tetrafunctional monomer pentaerythritol tetraacrylate ethoxylate (PPTTA).

[0038] Preferably, in the photocurable monomer, the mass ratio of o-phenylphenoxyethyl acrylate to pentaerythritol tetraacrylate is 1:(1.5~2.5), more preferably 1:2. This invention achieves both high single-layer strength and curing depth by controlling the mass ratio of o-phenylphenoxyethyl acrylate to pentaerythritol tetraacrylate within the above range. If the proportion of the high refractive index (1.576) monomer is too high, the over-curing width decreases, and the precision improves, but the strength of the single layer decreases. In multilayer printing, this can easily lead to a decrease in interlayer bonding force and delamination. If the proportion of the high refractive index (1.576) monomer is too low, the curing depth increases, the over-curing width increases, the precision decreases, and the internal stress increases, making warping and deformation more likely.

[0039] Preferably, in the photocurable monomer, the mass ratio of o-phenylphenoxyethyl acrylate to 1,6-hexanediol diacrylate is 1:(0.5~1.5), more preferably 1:1. This invention achieves both high solids content and high precision by controlling the mass ratio of o-phenylphenoxyethyl acrylate to 1,6-hexanediol diacrylate within the above range. If the proportion of HDDA monomer is too high, the over-curing width increases, and the precision decreases; if the proportion of HDDA monomer is too low, on the one hand, it will lead to an increase in slurry viscosity, making it difficult to obtain ceramic slurries with higher solids content, and on the other hand, it will lead to a decrease in the strength of the green body.

[0040] In this embodiment, in step S2, the mass ratio of the photocurable prepolymer to the photocurable monomer is 1:(3.5-4.5), and more specifically 1:4.

[0041] In this embodiment, in step S2, the ball milling method is planetary ball milling under vacuum conditions, the milling time is 5~10 minutes, the rotation speed is 1000~2000 rpm, and the vacuum degree is -100~-95 kPa. This invention achieves uniform mixing of materials through vacuum ball milling and performs vacuum degassing on the materials.

[0042] In this embodiment, in step S3, the volume percentage of modified aluminum nitride powder in the photocurable ceramic slurry is 50% to 55%. By controlling the volume percentage of modified aluminum nitride powder within the above range, this invention can achieve uniform slurry spreading and obtain aluminum nitride ceramic blanks with good printing quality and high density.

[0043] In this embodiment, in step S3, the second wetting and dispersing agent is a polyphosphate ester wetting and dispersing agent, and its addition amount is 2% to 4% of the mass of the modified aluminum nitride powder.

[0044] In some specific embodiments of the present invention, the second wetting and dispersing agent is BYK110.

[0045] In this embodiment, in step S3, the plasticizer is at least one of dioctyl phthalate (DOP) or dibutyl phthalate (DBP), and its addition amount is 4% to 10% of the mass of the photocurable ceramic slurry.

[0046] In this embodiment, in step S3, the photoinitiator is at least one of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO) and 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide (TMO), and its addition amount is 0.5% to 1.5% of the mass of the photocurable premix.

[0047] In this embodiment, in step S3, the ball milling method is planetary ball milling under vacuum conditions. The milling time is 5-20 minutes, the rotation speed is 1500-2000 rpm, the vacuum degree is -100--95 kPa, and the milling media are zirconia balls with a diameter of 2-5 mm. The mass ratio of zirconia balls to slurry is 1:(20-30). This invention achieves uniform mixing of materials through vacuum ball milling and performs vacuum degassing on the materials.

[0048] In this embodiment, step S4 uses surface exposure with a wavelength of 405 nm and an exposure energy of 36~48 mJ / cm². 2 The slice thickness is 20~30μm.

[0049] In this embodiment, step S5, the pyrolysis process includes: in a protective atmosphere, first heating to 250~350℃ and holding for 1~3 hours, then heating to 500~600℃ and holding for 1~3 hours, with a heating rate of 0.5~2℃ / min. By employing the above-mentioned staged holding process, this invention ensures the complete pyrolysis of various organic substances within the billet, avoiding the generation of defects.

[0050] In this embodiment, step S5 includes the following steps: in air, the degreasing temperature is 500~600 ℃, the holding time is 2~4 hours, and the heating rate is 0.5~2℃ / min.

[0051] In this embodiment, step S5 includes the following sintering process: pressureless sintering in a nitrogen atmosphere, sintering temperature of 1600~1800℃, further 1680~1720℃, and holding time of 1~10h, further 3~5h.

[0052] This invention does not limit the type of protective atmosphere, and those skilled in the art can select it according to the actual situation. In some specific embodiments of this invention, the protective atmosphere is nitrogen or argon, etc.

[0053] In a second aspect, the present invention provides a high thermal conductivity ceramic material, which is obtained by the additive manufacturing method of the high thermal conductivity ceramic material provided in the first aspect of the present invention.

[0054] Example 1

[0055] (1) Add 80g of aluminum nitride powder (average particle size 1.68μm), 2.4g of yttrium fluoride (average particle size 1.5μm), 1.6g of samarium fluoride (average particle size 1.8μm), 0.42g of wetting and dispersing agent BYK110 and 60g of anhydrous ethanol to a ball mill jar. The grinding balls are zirconia balls with a diameter of 2-10mm and a total weight of 240g. The mixture is ball-milled on a planetary ball mill for 6 hours at a speed of 365rpm. The slurry is poured out, dried at 70℃ and then passed through a 100-mesh sieve to obtain modified aluminum nitride powder.

[0056] (2) The monofunctional monomer OPPEA, the difunctional monomer HDDA, the tetrafunctional monomer PPTTA and the prepolymer difunctional aliphatic polyurethane acrylate (viscosity ~350mPa·s) were mixed in a planetary high-speed vacuum mixer at a mass ratio of 1:1:2:1, with a speed of 1000rpm, a mixing time of 10min and a vacuum degree of -98kPa to obtain a light-curing premix.

[0057] (3) 6.656g of photocurable premix, 1.6g of wetting and dispersing agent BYK110, 2.163g of dioctyl phthalate, 0.065g of photoinitiator TPO and 40g of modified aluminum nitride powder were added sequentially into a light-shielding plastic container, and 2g of zirconia grinding balls with a diameter of 2-5mm were added. The mixture was then mixed in a planetary high-speed vacuum mixer at a speed of 2000rpm for 15min and a vacuum degree of -98kPa to obtain a photocurable ceramic slurry with a volume percentage of modified aluminum nitride powder of 55vol%.

[0058] (4) Pour the photocurable ceramic slurry into the material tank of the 3D printer, use surface exposure, wavelength 405nm, and set the exposure energy to 36mJ / cm. 2 This resulted in a single-layer curing depth of 50~55μm. Based on the three-dimensional model of the component, the slice thickness was set to 25μm, and layer-by-layer exposure printing was performed to obtain an aluminum nitride ceramic preform. The over-curing width was measured to be 85μm.

[0059] (5) The above-mentioned aluminum nitride ceramic blank was placed in a degreasing furnace and heated to 300℃ at a rate of 0.5℃ / min under flowing nitrogen atmosphere, and held for 1 hour. Then, the temperature was further increased to 550℃ and held for 2 hours. After cooling in the furnace, the blank was degreased by heating to 600℃ at a rate of 0.5℃ / min under air atmosphere for 2 hours. The sample was then sintered under nitrogen atmosphere without pressure at a sintering temperature of 1720℃ for 3 hours. The thermal conductivity of the prepared aluminum nitride ceramic was 219 W / m·K.

[0060] Example 2

[0061] (1) Add 80g of aluminum nitride powder (average particle size 1.68μm), 2.4g of yttrium fluoride (average particle size 1.5μm), 1.6g of samarium fluoride (average particle size 1.8μm), 0.42g of wetting and dispersing agent BYK110 and 60g of anhydrous ethanol to a ball mill jar. The grinding balls are zirconia balls with a diameter of 2-10mm and a total weight of 240g. The mixture is ball-milled on a planetary ball mill for 6 hours at a speed of 365rpm. The slurry is poured out, dried at 70℃ and then passed through a 100-mesh sieve to obtain modified aluminum nitride powder.

[0062] (2) The monofunctional monomer OPPEA, the difunctional monomer HDDA, the tetrafunctional monomer PPTTA and the prepolymer difunctional aliphatic polyurethane acrylate (viscosity ~350mPa·s) were mixed in a planetary high-speed vacuum mixer at a mass ratio of 1:1:2:1, with a speed of 1000rpm, a mixing time of 10min and a vacuum degree of -98kPa to obtain a light-curing premix.

[0063] (3) 6.656g of photocurable premix, 1.6g of wetting and dispersing agent BYK110, 2.313g of dibutyl phthalate (DBP), 0.065g of photoinitiator TPO and 40g of modified aluminum nitride powder were added sequentially into a light-proof plastic container, and 2g of zirconia grinding balls with a diameter of 2-5mm were added. The mixture was then mixed in a planetary high-speed vacuum mixer at a speed of 2000rpm for 15min and a vacuum degree of -98kPa to obtain a photocurable ceramic slurry.

[0064] (4) Pour the photocurable ceramic slurry into the material tank of the 3D printer, use surface exposure, wavelength 405nm, and set the exposure energy to 48mJ / cm. 2 This resulted in a single-layer curing depth of 50~55μm. Based on the three-dimensional model of the component, the slice thickness was set to 25μm, and layer-by-layer exposure printing was performed to obtain an aluminum nitride ceramic preform. The over-curing width was measured to be 96μm.

[0065] (5) The above-mentioned aluminum nitride ceramic blank was placed in a degreasing furnace and heated to 300℃ at a rate of 0.5℃ / min under flowing nitrogen atmosphere, and held for 1 hour. Then, the temperature was further increased to 550℃ and held for 2 hours. After cooling in the furnace, the temperature was increased to 600℃ at a rate of 0.5℃ / min and held for 2 hours under air atmosphere for degreasing treatment. The sample was then sintered under nitrogen atmosphere without pressure at a sintering temperature of 1720℃ for 3 hours. The thermal conductivity of the prepared aluminum nitride ceramic was 220 W / m·K.

[0066] Example 3

[0067] (1) Add 80g of aluminum nitride powder (average particle size 1.2μm), 1.6g of yttrium fluoride (average particle size 1.5μm), 4.0g of samarium oxide (average particle size 2.0μm), 0.856g of wetting and dispersing agent BYK110 and 65g of anhydrous ethanol to a ball mill jar. The grinding balls are zirconia balls with a diameter of 2-10mm and a total weight of 240g. The ball mill is run on a planetary ball mill for 6 hours at a speed of 365rpm. The slurry is poured out, dried at 70℃ and then passed through a 100-mesh sieve to obtain modified aluminum nitride powder.

[0068] (2) The monofunctional monomer OPPEA, the difunctional monomer HDDA, the tetrafunctional monomer PPTTA and the prepolymer difunctional aliphatic polyurethane acrylate (viscosity ~350mPa·s) were mixed in a planetary high-speed vacuum mixer at a mass ratio of 1:1:2:1, with a speed of 1500rpm, a mixing time of 5min and a vacuum degree of -98kPa to obtain a light-curing premix.

[0069] (3) 8.177g of photocurable premix, 0.8g of wetting and dispersing agent BYK110, 3.509g of dioctyl phthalate, 0.041g of photoinitiator TMO and 40g of modified aluminum nitride powder were added sequentially into a light-shielding plastic container, and 2g of zirconia grinding balls with a diameter of 2-5mm were added. The mixture was then mixed in a planetary high-speed vacuum mixer at a speed of 1500rpm for 20min and a vacuum degree of -98kPa to obtain a photocurable ceramic slurry with a volume percentage of 50vol% of modified aluminum nitride powder.

[0070] (4) Pour the photocurable ceramic slurry into the material tank of the 3D printer, use surface exposure, wavelength 405nm, and set the exposure energy to 48mJ / cm. 2 This resulted in a single-layer curing depth of 50~55μm. Based on the three-dimensional model of the component, the slice thickness was set to 25μm, and layer-by-layer exposure printing was performed to obtain an aluminum nitride ceramic preform. The over-curing width was measured to be 75μm.

[0071] (5) The above-mentioned aluminum nitride ceramic blank was placed in a degreasing furnace and heated to 300℃ at a rate of 0.5℃ / min under flowing nitrogen atmosphere, and held for 1 hour. Then, the temperature was further increased to 550℃ and held for 2 hours. After cooling in the furnace, the blank was degreased again under air atmosphere by heating to 550℃ at a rate of 0.5℃ / min and holding for 2 hours. The sample was then sintered under nitrogen atmosphere without pressure at a sintering temperature of 1680℃ for 5 hours. The thermal conductivity of the prepared aluminum nitride ceramic was 206 W / m·K.

[0072] Comparative Example 1

[0073] (1) Add 80g of aluminum nitride powder (average particle size 1.68μm), 2.4g of yttrium fluoride (average particle size 1.5μm), 1.6g of samarium fluoride (average particle size 1.8μm), 0.42g of wetting and dispersing agent BYK110 and 60g of anhydrous ethanol to a ball mill jar. The grinding balls are zirconia balls with a diameter of 2-10mm and a total weight of 240g. The mixture is ball-milled on a planetary ball mill for 6 hours at a speed of 365rpm. The slurry is poured out, dried at 70℃ and then passed through a 100-mesh sieve to obtain modified aluminum nitride powder.

[0074] (2) The monofunctional monomer OPPEA, the difunctional monomer HDDA, the tetrafunctional monomer PPTTA and the prepolymer difunctional aliphatic polyurethane acrylate (viscosity ~350mPa·s) were mixed in a planetary high-speed vacuum mixer at a mass ratio of 1:1:2:1, with a speed of 1000rpm, a mixing time of 10min and a vacuum degree of -98kPa to obtain a light-curing premix.

[0075] (3) 6.656g of photocurable premix, 1.6g of wetting and dispersing agent BYK110, 2.163g of dioctyl phthalate, 0.065g of photoinitiator TPO and 40g of modified aluminum nitride powder were added sequentially into a light-proof plastic container, and 2g of zirconia grinding balls with a diameter of 2-5mm were added. The mixture was then mixed in a planetary high-speed vacuum mixer at a speed of 2000rpm for 15min and a vacuum degree of -98kPa to obtain a photocurable ceramic slurry.

[0076] (4) Pour the photocurable ceramic slurry into the material tank of the 3D printer, use surface exposure, wavelength 405nm, and set the exposure energy to 36mJ / cm. 2 This resulted in a single-layer curing depth of 50~55μm. Based on the three-dimensional model of the component, the slice thickness was set to 25μm, and layer-by-layer exposure printing was performed to obtain an aluminum nitride ceramic preform. The over-curing width was measured to be 85μm.

[0077] (5) The above-mentioned aluminum nitride ceramic green body was placed in a degreasing furnace and heated to 300℃ at a rate of 0.5℃ / min in air and held for 1 hour. Then, the temperature was further increased to 550℃ and held for 2 hours. Then, the temperature was further increased to 600℃ at a rate of 0.5℃ / min and held for 2 hours for degreasing treatment. After degreasing treatment, micro-cracks appeared on the surface and sides of the sample. It can be seen that the photosensitive resin polymerized in the green body decomposed violently in a short time, causing defects such as cracking in the ceramic sample during the degreasing process.

[0078] Comparative Example 2

[0079] (1) Add 80g of aluminum nitride powder (average particle size 1.68μm), 2.4g of yttrium fluoride (average particle size 1.5μm), 1.6g of samarium fluoride (average particle size 1.8μm), 0.42g of wetting and dispersing agent BYK110 and 60g of anhydrous ethanol to a ball mill jar. The grinding balls are zirconia balls with a diameter of 2-10mm and a total weight of 240g. The mixture is ball-milled on a planetary ball mill for 6 hours at a speed of 365rpm. The slurry is poured out, dried at 70℃ and then passed through a 100-mesh sieve to obtain modified aluminum nitride powder.

[0080] (2) The monofunctional monomer OPPEA, the difunctional monomer HDDA, the tetrafunctional monomer PPTTA and the prepolymer difunctional aliphatic polyurethane acrylate (viscosity ~350mPa·s) were mixed in a planetary high-speed vacuum mixer at a mass ratio of 1:1:2:1, with a speed of 1000rpm, a mixing time of 10min and a vacuum degree of -98kPa to obtain a light-curing premix.

[0081] (3) 6.656g of photocurable premix, 1.6g of wetting and dispersing agent BYK110, 2.163g of dioctyl phthalate, 0.065g of photoinitiator TPO and 40g of modified aluminum nitride powder were added sequentially into a light-proof plastic container, and 2g of zirconia grinding balls with a diameter of 2-5mm were added. The mixture was then mixed in a planetary high-speed vacuum mixer at a speed of 2000rpm for 15min and a vacuum degree of -98kPa to obtain a photocurable ceramic slurry.

[0082] (4) Pour the photocurable ceramic slurry into the material tank of the 3D printer, use surface exposure, wavelength 405nm, and set the exposure energy to 36mJ / cm. 2 This resulted in a single-layer curing depth of 50~55μm. Based on the three-dimensional model of the component, the slice thickness was set to 25μm, and layer-by-layer exposure printing was performed to obtain an aluminum nitride ceramic preform. The over-curing width was measured to be 85μm.

[0083] (5) The above-mentioned aluminum nitride ceramic green body was placed in a degreasing furnace and heated to 300℃ at a rate of 0.5℃ / min under flowing nitrogen atmosphere, and held for 1 hour. Then, the temperature was increased to 550℃ and held for 2 hours, followed by a further increase to 600℃ at a rate of 0.5℃ / min and held for 2 hours. No cracks or delamination were observed in the degreased green body. The degreased sample was then subjected to pressureless sintering in a nitrogen atmosphere at a sintering temperature of 1720℃ for 3 hours. The density of the prepared aluminum nitride ceramic was only 2.57 g / cm³. 3 It is much lower than the 3.31 g / cm³ of Example 1. 3This indicates that the ceramic cannot be fully densified, with a thermal conductivity of only 46 W / m·K. This is because the 3D-printed aluminum nitride blank contains a lot of organic matter, and the high carbon residue after thermal decomposition hinders the densification of the ceramic during sintering.

[0084] Comparative Example 3

[0085] (1) Add 80g of aluminum nitride powder (average particle size 1.68μm), 2.4g of yttrium fluoride (average particle size 1.5μm), 1.6g of samarium fluoride (average particle size 1.8μm) and 60g of anhydrous ethanol to a ball mill jar. Use zirconia balls with a diameter of 2-10mm and a total weight of 240g as grinding balls. Ball mill for 6 hours on a planetary ball mill at a speed of 365rpm. Pour out the slurry, dry it at 70℃, and then pass it through a 100-mesh sieve to obtain modified aluminum nitride powder.

[0086] (2) The monofunctional monomer OPPEA, the difunctional monomer HDDA, the tetrafunctional monomer PPTTA and the prepolymer difunctional aliphatic polyurethane acrylate (viscosity ~350mPa·s) were mixed in a planetary high-speed vacuum mixer at a mass ratio of 1:1:2:1, with a speed of 1000rpm, a mixing time of 10min and a vacuum degree of -98kPa to obtain a light-curing premix.

[0087] (3) 6.656g of photocurable premix, 1.8g of wetting and dispersing agent BYK110, 2.163g of dioctyl phthalate, 0.065g of photoinitiator TPO and 40g of modified aluminum nitride powder were added sequentially into a light-proof plastic container, and 2g of zirconia grinding balls with a diameter of 2-5mm were added. The mixture was then mixed in a planetary high-speed vacuum mixer at a speed of 2000rpm for 15min and a vacuum degree of -98kPa to obtain a photocurable ceramic slurry.

[0088] (4) Pour the photocurable ceramic slurry into the material tank of the 3D printer, use surface exposure, wavelength 405nm, and set the exposure energy to 36mJ / cm. 2 This resulted in a single-layer curing depth of 50~55μm. Based on the three-dimensional model of the component, the slice thickness was set to 25μm, and layer-by-layer exposure printing was performed to obtain an aluminum nitride ceramic preform. The over-curing width was measured to be 137μm.

[0089] (5) The above-mentioned aluminum nitride ceramic blank was placed in a degreasing furnace and heated to 300℃ at a rate of 0.5℃ / min under flowing nitrogen atmosphere, and held for 1 hour. Then, the temperature was further increased to 550℃ and held for 2 hours. After cooling in the furnace, the temperature was increased to 600℃ at a rate of 0.5℃ / min and held for 2 hours under air atmosphere for degreasing treatment. Then, the sample was sintered without pressure in a nitrogen atmosphere at a sintering temperature of 1720℃ and a holding time of 3 hours. The thermal conductivity of the prepared aluminum nitride ceramic was 194 W / m·K. It can be seen that when the wetting and dispersing agent is added to the photocurable ceramic slurry at one time, it affects the uniform dispersion of the sintering aid in the aluminum nitride powder, reducing the printing accuracy and the thermal conductivity of the ceramic.

[0090] Comparative Example 4

[0091] (1) Add 80g of aluminum nitride powder (average particle size 1.68μm), 2.4g of yttrium fluoride (average particle size 1.5μm), 1.6g of samarium fluoride (average particle size 1.8μm), 0.42g of wetting and dispersing agent BYK110 and 60g of anhydrous ethanol to a ball mill jar. The grinding balls are zirconia balls with a diameter of 2-10mm and a total weight of 240g. The mixture is ball-milled on a planetary ball mill for 6 hours at a speed of 365rpm. The slurry is poured out, dried at 70℃ and then passed through a 100-mesh sieve to obtain modified aluminum nitride powder.

[0092] (2) The monofunctional monomer OPPEA, the difunctional monomer HDDA, the tetrafunctional monomer PPTTA and the prepolymer difunctional aliphatic polyurethane acrylate (viscosity ~350mPa·s) were mixed in a planetary high-speed vacuum mixer at a mass ratio of 1:1:2:1, with a speed of 1000rpm, a mixing time of 10min and a vacuum degree of -98kPa to obtain a light-curing premix.

[0093] (3) 6.656g of photocurable premix, 1.6g of wetting and dispersing agent BYK110, 0.065g of photoinitiator TPO and 40g of modified aluminum nitride powder were added to a light-proof plastic container in sequence, and 2g of zirconia grinding balls with a diameter of 2-5mm were added. The mixture was then mixed in a planetary high-speed vacuum mixer at a speed of 2000rpm for 15min and a vacuum degree of -98kPa to obtain a photocurable ceramic slurry.

[0094] (4) Pour the photocurable ceramic slurry into the material tank of the 3D printer, use surface exposure, wavelength 405nm, and set the exposure energy to 36mJ / cm. 2 This resulted in a single-layer curing depth of 50~55μm. Based on the three-dimensional model of the component, the slice thickness was set to 25μm, and layer-by-layer exposure printing was performed to obtain an aluminum nitride ceramic preform. The over-curing width was measured to be 200μm.

[0095] (5) The above-mentioned aluminum nitride ceramic blank was placed in a degreasing furnace and heated to 300℃ at a rate of 0.5℃ / min under flowing nitrogen atmosphere and held for 1 hour. Then, the temperature was increased to 550℃ and held for 2 hours. After cooling in the furnace, the temperature was increased to 600℃ at a rate of 0.5℃ / min and held for 2 hours under air atmosphere for degreasing treatment. Then, the sample was sintered under nitrogen atmosphere without pressure at a sintering temperature of 1720℃ and a holding time of 3 hours. The thermal conductivity of the prepared ceramic was 174 W / m·K. Scanning electron microscopy revealed that there were micropores and cracks in some areas of the sample. Figure 4 This indicates that plasticizers not only help release the internal stress generated during photocuring and form microchannels during degreasing, thereby inhibiting the formation of pores and microcracks in the ceramic body after sintering, but also help reduce the over-curing width of 3D printing and improve the accuracy of the printed blank.

[0096] Comparative Example 5

[0097] (1) Add 80g of aluminum nitride powder (average particle size 1.2μm), 1.6g of yttrium fluoride (average particle size 1.5μm), 4.0g of samarium oxide (average particle size 2.0μm), 0.856g of wetting and dispersing agent BYK110 and 65g of anhydrous ethanol to a ball mill jar. The grinding balls are zirconia balls with a diameter of 2-10mm and a total weight of 240g. The ball mill is run on a planetary ball mill for 6 hours at a speed of 365rpm. The slurry is poured out, dried at 70℃ and then passed through a 100-mesh sieve to obtain modified aluminum nitride powder.

[0098] (2) The monofunctional monomer OPPEA, the tetrafunctional monomer PPTTA and the prepolymer difunctional aliphatic polyurethane acrylate (viscosity ~350mPa·s) were mixed in a planetary high-speed vacuum mixer at a mass ratio of 2:2:1. The speed was 1500rpm, the mixing time was 5min, and the vacuum degree was -98kPa to obtain the light-curing premix.

[0099] (3) 8.177g of photocurable premix, 0.8g of wetting and dispersing agent BYK110, 3.509g of dioctyl phthalate, 0.041g of photoinitiator TMO and 40g of modified aluminum nitride powder were added sequentially into a light-proof plastic container, and 2g of zirconia grinding balls with a diameter of 2-5mm were added. The mixture was then mixed in a planetary high-speed vacuum mixer at a speed of 1500rpm for 20min and a vacuum degree of -98kPa to obtain a photocurable ceramic slurry.

[0100] (4) Pour the photocurable ceramic slurry into the material tank of the 3D printer, use surface exposure, wavelength 405nm, and set the exposure energy to 36mJ / cm. 2This results in a single-layer curing depth of 50~55μm. The single-layer cured film is soft and has low strength. During the printing process, the cured layer is easily rolled up, causing local defects in the blank and making it impossible to obtain a complete blank structure.

[0101] Comparative Example 6

[0102] (1) Add 80g of aluminum nitride powder (average particle size 1.2μm), 1.6g of yttrium fluoride (average particle size 1.5μm), 4.0g of samarium oxide (average particle size 2.0μm), 0.856g of wetting and dispersing agent BYK110 and 65g of anhydrous ethanol to a ball mill jar. The grinding balls are zirconia balls with a diameter of 2-10mm and a total weight of 240g. The ball mill is run on a planetary ball mill for 6 hours at a speed of 365rpm. The slurry is poured out, dried at 70℃ and then passed through a 100-mesh sieve to obtain modified aluminum nitride powder.

[0103] (2) The difunctional monomer HDDA, the tetrafunctional monomer PPTTA and the prepolymer difunctional aliphatic polyurethane acrylate (viscosity ~350mPa·s) were mixed in a planetary high-speed vacuum mixer at a mass ratio of 2:2:1. The mixing speed was 1500rpm, the mixing time was 5min, and the vacuum degree was -98kPa to obtain the photocurable premix.

[0104] (3) 8.177g of photocurable premix, 0.8g of wetting and dispersing agent BYK110, 3.509g of dioctyl phthalate, 0.041g of photoinitiator TMO and 40g of modified aluminum nitride powder were added sequentially into a light-proof plastic container, and 2g of zirconia grinding balls with a diameter of 2-5mm were added. The mixture was then mixed in a planetary high-speed vacuum mixer at a speed of 1500rpm for 20min and a vacuum degree of -98kPa to obtain a photocurable ceramic slurry.

[0105] (4) Pour the photocurable ceramic slurry into the material tank of the 3D printer, use surface exposure, wavelength 405nm, and set the exposure energy to 48mJ / cm. 2 This resulted in a single-layer curing depth of 50~55μm. Based on the three-dimensional model of the component, the slice thickness was set to 25μm, and layer-by-layer exposure printing was performed to obtain an aluminum nitride ceramic preform. The over-curing width was measured to be 170μm.

[0106] (5) The above-mentioned aluminum nitride ceramic preform was placed in a degreasing furnace and heated to 300℃ at a rate of 0.5℃ / min under flowing nitrogen atmosphere, and held for 1 hour. Then, the temperature was further increased to 550℃ and held for 2 hours. After cooling in the furnace, the preform was degreased again under air atmosphere at a rate of 0.5℃ / min to 550℃ and held for 2 hours. The sample was then sintered without pressure in a nitrogen atmosphere at a sintering temperature of 1680℃ for 5 hours. The thermal conductivity of the prepared aluminum nitride ceramic was 200 W / m·K. It can be seen that when there is no high refractive index monomer in the photosensitive resin, the accuracy of the printed preform is significantly reduced.

[0107] Comparative Example 7

[0108] (1) Add 80g of aluminum nitride powder (average particle size 1.68μm), 2.4g of yttrium fluoride (average particle size 1.5μm), 1.6g of samarium fluoride (average particle size 1.8μm), 0.42g of wetting and dispersing agent BYK110 and 60g of anhydrous ethanol to a ball mill jar. The grinding balls are zirconia balls with a diameter of 2-10mm and a total weight of 240g. The mixture is ball-milled on a planetary ball mill for 6 hours at a speed of 365rpm. The slurry is poured out, dried at 70℃ and then passed through a 100-mesh sieve to obtain modified aluminum nitride powder.

[0109] (2) According to the mass ratio of monofunctional monomer OPPEA, difunctional monomer HDDA, tetrafunctional monomer PPTTA and prepolymer epoxy acrylate (viscosity 30~60Pa·s) 1:1:2:1, the prepolymer epoxy acrylate was heated to 60℃ and added to the monomers. The mixture was then mixed in a planetary high-speed vacuum mixer at a speed of 1000rpm for 10min and a vacuum degree of -98kPa to obtain a light-curing premix.

[0110] (3) 6.656g of photocurable premix, 1.6g of wetting and dispersing agent BYK110, 2.163g of dioctyl phthalate, 0.065g of photoinitiator TPO and 40g of modified aluminum nitride powder were added sequentially into a light-proof plastic container, and 2g of zirconia grinding balls with a diameter of 2-5mm were added. The mixture was then mixed in a planetary high-speed vacuum mixer at a speed of 2000rpm for 15min and a vacuum degree of -98kPa to obtain a photocurable ceramic slurry.

[0111] (4) Pour the photocurable ceramic slurry into the 3D printer's slurry tank. Due to the high viscosity and poor fluidity of the slurry, it is difficult to spread it evenly on the printing table after the scraper passes over it, making it impossible to perform multi-layer printing.

[0112] Comparative Example 8

[0113] (1) Add 80g of aluminum nitride powder (average particle size 1.68μm), 2.4g of yttrium fluoride (average particle size 1.5μm), 1.6g of samarium fluoride (average particle size 1.8μm), 0.42g of wetting and dispersing agent BYK110 and 60g of anhydrous ethanol to a ball mill jar. The grinding balls are zirconia balls with a diameter of 2-10mm and a total weight of 240g. The mixture is ball-milled on a planetary ball mill for 6 hours at a speed of 365rpm. The slurry is poured out, dried at 70℃ and then passed through a 100-mesh sieve to obtain modified aluminum nitride powder.

[0114] (2) The monofunctional monomer OPPEA, the difunctional monomer HDDA, the tetrafunctional monomer PPTTA and the prepolymer difunctional aliphatic polyurethane acrylate (viscosity ~350mPa·s) were mixed in a planetary high-speed vacuum mixer at a mass ratio of 1:1:2:1, with a speed of 1000rpm, a mixing time of 10min and a vacuum degree of -98kPa to obtain a light-curing premix.

[0115] (3) 11.422g of photocurable premix, 1.6g of wetting and dispersing agent BYK110, 2.644g of dioctyl phthalate, 0.114g of photoinitiator TPO and 40g of modified aluminum nitride powder were added to a light-shielding plastic container in sequence, and 2g of zirconia grinding balls with a diameter of 2-5mm were added. The mixture was then mixed in a planetary high-speed vacuum mixer at a speed of 2000rpm for 15min and a vacuum degree of -98kPa to obtain a photocurable ceramic slurry with a volume percentage of 45vol% of modified aluminum nitride powder.

[0116] (4) Pour the photocurable ceramic slurry into the material tank of the 3D printer, use surface exposure, wavelength 405nm, and set the exposure energy to 36mJ / cm. 2 This resulted in a single-layer curing depth of 50~55μm. Based on the three-dimensional model of the component, the slice thickness was set to 25μm, and layer-by-layer exposure printing was performed to obtain an aluminum nitride ceramic preform. The over-curing width was measured to be 82μm.

[0117] (5) The above-mentioned aluminum nitride ceramic green body was placed in a degreasing furnace and heated to 300℃ at a rate of 0.5℃ / min under flowing nitrogen atmosphere and held for 1 hour. Then, the temperature was further increased to 550℃ and held for 2 hours. After cooling in the furnace, it was degreased by heating to 600℃ at a rate of 0.5℃ / min under air atmosphere and held for 2 hours. Then, the sample was sintered under nitrogen atmosphere without pressure at a sintering temperature of 1720℃ and a holding time of 3 hours. The thermal conductivity of the prepared aluminum nitride ceramic was 164 W / m·K. It can be seen that when the solid content of the slurry is less than 50 vol%, although a green body with tight interlayer bonding and a printing accuracy of less than 100 μm can be obtained, the density of the prepared ceramic decreases and the thermal conductivity is less than 200 W / m·K due to the low solid content.

[0118] Comparative Example 9

[0119] (1) Add 80g of aluminum nitride powder (average particle size 1.68μm), 2.4g of yttrium fluoride (average particle size 1.5μm), 1.6g of samarium fluoride (average particle size 1.8μm), 0.42g of wetting and dispersing agent BYK110 and 60g of anhydrous ethanol to a ball mill jar. The grinding balls are zirconia balls with a diameter of 2-10mm and a total weight of 240g. The mixture is ball-milled on a planetary ball mill for 6 hours at a speed of 365rpm. The slurry is poured out, dried at 70℃ and then passed through a 100-mesh sieve to obtain modified aluminum nitride powder.

[0120] (2) The monofunctional monomer OPPEA, the tetrafunctional monomer PPTTA and the prepolymer difunctional aliphatic polyurethane acrylate (viscosity ~350mPa·s) were mixed in a planetary high-speed vacuum mixer at a mass ratio of 2:2:1. The mixing speed was 1000rpm, the mixing time was 10min, and the vacuum degree was -98kPa to obtain the light-curing premix.

[0121] (3) 6.656g of photocurable premix, 1.6g of wetting and dispersing agent BYK110, 2.163g of dioctyl phthalate, 0.065g of photoinitiator TPO and 40g of modified aluminum nitride powder were added sequentially into a light-proof plastic container, and 2g of zirconia grinding balls with a diameter of 2-5mm were added. The mixture was then mixed in a planetary high-speed vacuum mixer at a speed of 2000rpm for 15min and a vacuum degree of -98kPa to obtain a photocurable ceramic slurry.

[0122] (4) Pour the photocurable ceramic slurry into the 3D printer's slurry tank. Due to the high viscosity and poor fluidity of the slurry, it is difficult to spread evenly on the printing table after the scraper passes over it, making it impossible to perform multi-layer printing.

[0123] Please see Figure 1 ,pass Figure 1 It can be seen that the modified aluminum nitride powder prepared in Example 1 of the present invention has an ultraviolet absorbance of 0.1271 at 405 nm, indicating that the present invention significantly reduces the absorbance of modified AlN powder by selecting appropriate sintering aids and wetting and dispersing agents and combining them with ball milling process.

[0124] Please see Figure 2 ,pass Figure 2 It can be seen that the aluminum nitride ceramic green body prepared in Example 1 of the present invention has a tight bond between layers and no defects such as delamination or pores.

[0125] Please see Figure 3 ,pass Figure 3It can be seen that the high thermal conductivity ceramic material prepared in Example 1 of the present invention has a complex shape, but after debinding and sintering, the shape remains intact and without cracks.

[0126] Please see Figure 4 ,pass Figure 4 It can be seen that the aluminum nitride ceramic material prepared in Comparative Example 4 (without plasticizer) of the present invention has poor contact between grains in some areas after sintering, and there are micro-cracks.

[0127] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An additive manufacturing method for a high thermal conductivity ceramic material, characterized in that, Includes the following steps: Aluminum nitride, sintering aid, first wetting and dispersing agent and organic solvent are first ball-milled and mixed, then dried and sieved to obtain modified aluminum nitride powder; The photocurable prepolymer and the photocurable monomer are mixed by a second ball milling process to obtain a photocurable premix. Under light-protected conditions, the modified aluminum nitride powder, the photocurable premix, the second wetting and dispersing agent, the plasticizer, and the photoinitiator are mixed by a third ball mill to obtain a photocurable ceramic slurry. Based on the three-dimensional model of the component, the photocurable ceramic slurry is used for layer-by-layer printing and curing to obtain an aluminum nitride ceramic preform; The aluminum nitride ceramic preform was sequentially pyrolyzed, degreased, and sintered to obtain a high thermal conductivity ceramic material. The aluminum nitride is micron-sized aluminum nitride with an average particle size of 1-2 μm; The sintering aid is a combination of samarium fluoride and yttrium fluoride, or a combination of samarium fluoride, samarium oxide and yttrium fluoride; its addition amount is 5% to 7% of the mass of the aluminum nitride, and its average particle size is 1-2 μm; The yttrium fluoride accounts for 25% to 60% of the total mass of the sintering aid; Both the first wetting and dispersing agent and the second wetting and dispersing agent are BYK110; The organic solvent is ethanol, and its addition amount is 70% to 80% of the total mass of the aluminum nitride and the sintering aid.

2. The additive manufacturing method for the high thermal conductivity ceramic material according to claim 1, characterized in that, During the first ball milling process, the ball milling method is planetary ball milling, the ball milling time is 5-10 hours, and the ball milling speed is 300-400 rpm; and / or, During the sieving process, the sieve mesh size is 100-200 mesh.

3. The additive manufacturing method for the high thermal conductivity ceramic material according to claim 1, characterized in that, The photocurable prepolymer is a difunctional aliphatic polyurethane acrylate; and / or... The photocurable monomer is a combination of o-phenylphenoxyethyl acrylate, 1,6-hexanediol diacrylate, and pentaerythritol ethoxylate tetraacrylate; and / or The mass ratio of the photocurable prepolymer to the photocurable monomer is 1:(3.5-4.5); and / or, During the second ball milling process, the ball milling method is a planetary ball milling under vacuum conditions, the ball milling time is 5~10 min, the rotation speed is 1000~2000 rpm, and the vacuum degree is -100~-95 kPa.

4. The additive manufacturing method for the high thermal conductivity ceramic material according to claim 3, characterized in that, In the photocurable monomer, the mass ratio of o-phenylphenoxyethyl acrylate to pentaerythritol tetraacrylate is 1:(1.5~2.5); and / or, The mass ratio of o-phenylphenoxyethyl acrylate to 1,6-hexanediol diacrylate is 1:(0.5~1.5).

5. The additive manufacturing method for the high thermal conductivity ceramic material according to claim 1, characterized in that, In the photocurable ceramic slurry, the modified aluminum nitride powder accounts for 50% to 55% by volume; and / or, The plasticizer is at least one of dioctyl phthalate or dibutyl phthalate, and its addition amount is 4% to 10% of the mass of the photocurable ceramic slurry; and / or, The photoinitiator is at least one selected from (2,4,6-trimethylbenzoyl)diphenylphosphine oxide and 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, and its addition amount is 0.5% to 1.5% of the mass of the photocurable premix; and / or, During the third ball milling process, the ball milling method is a planetary ball milling under vacuum conditions, with a milling time of 5 to 20 minutes, a rotation speed of 1500 to 2000 rpm, and a vacuum degree of -100 to -95 kPa.

6. The additive manufacturing method for the high thermal conductivity ceramic material according to claim 1, characterized in that, During the printing and curing process, surface exposure is used with a wavelength of 405nm and an exposure energy of 36~48mJ / cm. 2 The slice thickness is 20~30μm.

7. The additive manufacturing method for the high thermal conductivity ceramic material according to claim 1, characterized in that, The pyrolysis process includes: in a protective atmosphere, first heating to 250~350 °C and holding for 1~3 hours, then heating to 500~600 °C and holding for 1~3 hours, with a heating rate of 0.5~2 °C / min; and / or, The degreasing process includes: in air, degreasing at a temperature of 500~600 ℃, holding at that temperature for 2~4 hours, and a heating rate of 0.5~2 ℃ / min; and / or, The sintering process includes: pressureless sintering in a nitrogen atmosphere, with a sintering temperature of 1600~1800℃ and a holding time of 1~10h.

8. A high thermal conductivity ceramic material, characterized in that, The high thermal conductivity ceramic material is obtained by the additive manufacturing method of the high thermal conductivity ceramic material according to any one of claims 1 to 7.

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