A method for preparing aluminum nitride ceramic slurry and aluminum nitride ceramic based on stereolithography.

Abstract

This invention discloses an aluminum nitride ceramic slurry based on stereolithography and a method for preparing aluminum nitride ceramics, relating to the field of aluminum nitride ceramic additive manufacturing technology. The method for preparing the aluminum nitride ceramic slurry based on stereolithography provided by this invention utilizes a UV monomer with strong diluent properties as an active diluent and modifies the aluminum nitride ceramic powder with an acrylic block copolymer, effectively improving the surface wettability of aluminum nitride and its compatibility with photosensitive resins. This invention leverages the synergistic effect of the diluent and modifier to significantly reduce the viscosity of the aluminum nitride ceramic slurry, resulting in a ceramic slurry with good photocurability, low viscosity, and a solid content of 50-70 vol%, expanding the applications of photocurable aluminum nitride ceramics and enabling the preparation of high-performance aluminum nitride ceramics.

Description

Technical Field

[0001] This invention relates to the field of aluminum nitride ceramics technology, and in particular to an aluminum nitride ceramic slurry based on stereolithography and a method for preparing aluminum nitride ceramics. Background Technology

[0002] In recent years, the rapid development of electronic technology has led to a continuous reduction in the size of electronic components, posing significant challenges to the thermal conductivity and mechanical properties of electronic component materials. AlN ceramics, due to their high thermal conductivity, superior mechanical properties, corrosion resistance, good chemical stability, and matching thermal expansion coefficient with Si, have become ideal packaging materials for next-generation semiconductor devices and integrated circuits. 3D molding technology, a moldless manufacturing technique, provides greater design freedom for complex-shaped AlN ceramic parts and can meet the demands for personalized, precise, and rapid manufacturing.

[0003] The key to applying 3D molding technology in aluminum nitride ceramics lies in formulating aluminum nitride ceramic slurries with high solid content and low viscosity. Currently, there are very few aluminum nitride ceramic slurries that can be used for 3D printing, which greatly limits the application and development of 3D molding technology in aluminum nitride ceramics. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the viscosity of aluminum nitride ceramic slurry with high solid content (50-70 vol.%) is too high and unsuitable for photocuring. The present invention provides an aluminum nitride ceramic slurry with high solid content and low viscosity based on stereolithography, and provides high-performance aluminum nitride ceramic parts made from the slurry.

[0005] To address the above problems, the present invention proposes the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing aluminum nitride ceramic slurry based on stereolithography, comprising the following steps:

[0007] S1. Preparation of modified aluminum nitride powder: Take 85-95 parts of aluminum nitride powder, 1-10 parts of sintering aid, and 0.1-5 parts of acrylic block copolymer by mass, and mix them by ball milling. After ball milling, dry and sieve to obtain modified powder.

[0008] S2. Preparation of photosensitive resin premix: Take 14-76 parts by weight of reactive diluent, 14-76 parts by weight of polyfunctional acrylate monomer, and 5-30 parts by weight of plasticizer, and disperse and mix them by ultrasonication to obtain photosensitive resin premix.

[0009] S3. Preparation of aluminum nitride ceramic slurry: By volume percentage, take 50-70 vol.% of the modified powder, 27-47 vol.% of the photosensitive resin premix, 0.25-3 vol.% of the photoinitiator, and 0.25-3 vol.% of the polymeric dispersant, and mix them evenly at high speed to obtain aluminum nitride ceramic slurry.

[0010] Specifically, in step S1, during ball milling, zirconia grinding balls are used, and the mass ratio of zirconia grinding balls: anhydrous ethanol: powder is 2:2:1. Ball milling is performed in a planetary ball mill at a speed of 100–350 r / min for 1–6 h. After ball milling, the powder is dried to remove the solvent and sieved through a 200–300 mesh sieve to obtain modified aluminum nitride powder.

[0011] Furthermore, the aluminum nitride powder is nano-sized or submicron-sized aluminum nitride powder.

[0012] Furthermore, the acrylic block copolymer is BZ-2431 or KMT-3331. Compared with polyacrylic acid, the acrylic block copolymer of the present invention contains not only hydrophilic acrylic acid monomers, but also other hydrophobic monomers such as styrene and acrylate. Experiments have shown that the acrylic block copolymer modifies aluminum nitride powder by connecting the hydrophilic group at one end to the hydrophilic group on the surface of aluminum nitride, while the hydrophobic group at the other end contacts the resin system. That is, the aluminum nitride powder modified by the acrylic block copolymer is coated with an amorphous surface layer, which greatly improves the compatibility between the powder and the resin, effectively improves the wettability of aluminum nitride powder and photosensitive resin premix, reduces the shear viscosity of ceramic slurry, and is beneficial for photocuring printing.

[0013] Furthermore, the sintering aid is selected as SmF3. This invention uses samarium fluoride as a sintering aid. Compared to oxides, the addition of samarium fluoride does not introduce additional oxygen elements, and it has a stronger ability to remove oxygen from the raw materials, resulting in a better improvement in the thermal conductivity of aluminum nitride.

[0014] This invention uses SmF3 as a sintering aid, which can effectively eliminate oxygen impurities, purify and strengthen grain boundaries during the sintering process of aluminum nitride ceramic blanks, and ultimately produce aluminum nitride ceramic parts with dense structure, high thermal conductivity and excellent mechanical properties.

[0015] Furthermore, the reactive diluent is ethyl 2-ethyleneoxyethoxyacrylate (VEEA).

[0016] Furthermore, the multifunctional acrylate monomer is one or more of tripropylene glycol diacrylate (TPGDA), trimethylolpropane triacrylate (TMPTA), and pentaerythritol tetraacrylate (PPTTA).

[0017] Furthermore, the plasticizer is either dioctyl phthalate (DOP) or dibutyl phthalate (DBP).

[0018] Furthermore, the photoinitiator is selected from (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO), and the polymeric dispersant is selected from one or more of BYK-110, BYK-111, and KOS110.

[0019] Furthermore, in step S3, the equipment used for high-speed homogenization is a high-speed homogenizer with a rotation speed of 2000-2500 r / min and a mixing time of 1-5 min.

[0020] In a second aspect, the present invention provides an aluminum nitride ceramic slurry, which is prepared by the method for preparing aluminum nitride ceramic slurry based on stereolithography as described in the first aspect.

[0021] Thirdly, the present invention provides a method for preparing aluminum nitride ceramics, using the aluminum nitride ceramic slurry described in the second aspect, or the aluminum nitride ceramic slurry prepared by the method for preparing aluminum nitride ceramic slurry based on stereolithography described in the first aspect, as raw material, performing stereolithography to form a green body, and then degreasing and sintering the green body to obtain aluminum nitride ceramics; wherein the solid content of the aluminum nitride ceramic slurry is 50-70 vol.%.

[0022] Specifically, during the photopolymerization molding process, the 3D model of the ceramic part to be printed is layered using 3D software to determine the shape of each layer to be exposed and polymerized, and a printing control program is generated; photopolymerization printing is performed to obtain a ceramic blank; the ceramic blank is cleaned; the cleaned ceramic blank is degreased and sintered to obtain aluminum nitride ceramic.

[0023] Furthermore, degreasing is carried out using a two-step vacuum-air debinding method, the specific process of which is as follows:

[0024] First, perform vacuum debinding: In the vacuum debinding furnace, first raise the temperature from room temperature to 100-160℃ and hold for 1-2 hours, then raise the temperature to 300-350℃ and hold for 1-2 hours, and finally raise the temperature to 450-550℃ and hold for 3-6 hours before cooling to room temperature with the furnace; the heating rate is 0.5-2℃ / min.

[0025] Then, air debinding is performed: In the air debinding oven, the temperature is first raised from room temperature to 100-160℃ and held for 1-2 hours, then raised to 300-350℃ and held for 1-2 hours, and finally raised to 350-450℃ and held for 2-6 hours before being cooled to room temperature with the oven; the heating rate is 0.5-2℃ / min.

[0026] Furthermore, the specific sintering operation is as follows: sintering is carried out in a nitrogen atmosphere sintering furnace at a temperature of 1750–1850℃ for 2–6 hours.

[0027] Fourthly, the present invention provides an aluminum nitride ceramic, which is prepared by the preparation method described in the third aspect.

[0028] Compared with the prior art, the technical effects achieved by the present invention include:

[0029] This invention provides a method for preparing aluminum nitride ceramic slurry based on stereolithography. The method utilizes an acrylic block copolymer to modify the aluminum nitride ceramic powder, effectively improving the surface wettability of aluminum nitride and its compatibility with photosensitive resins. By leveraging the synergistic effect of a diluent and modifier, this invention significantly reduces the viscosity of the aluminum nitride ceramic slurry, resulting in a ceramic slurry with good photocurability, low viscosity, and a solid content of 50-70 vol%. This expands the applications of photocurable aluminum nitride ceramics and enables the preparation of high-performance aluminum nitride ceramics.

[0030] Instruction manual illustrations

[0031] Figure 1 The rheological diagrams are for the slurry in Example 5 and Comparative Example 2. Detailed Implementation

[0032] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the embodiments described below are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] Example 1

[0034] This embodiment provides an aluminum nitride ceramic slurry based on stereolithography and the aluminum nitride ceramic prepared from the slurry. The aluminum nitride ceramic slurry prepared in this embodiment has a solid content of 70 vol.%, and uses 5 wt% KMT-3331 as the modifier, 5 wt% SmF3 as the sintering aid, and VEEA as the reactive diluent.

[0035] The specific implementation steps are as follows:

[0036] 1) Weigh 60g of aluminum nitride powder, place it in an oven, and dry it at 60℃ for 2 hours for later use.

[0037] 2) Preparation of modified aluminum nitride powder: The dried aluminum nitride powder was placed in 120g of anhydrous ethanol, and then 3g of KMT-3331, 3.2g of SmF3 and 120g of zirconia grinding balls were added. The above materials were ball-milled by planetary ball mill at a speed of 350r / min for 6h. After ball milling, the anhydrous ethanol was removed by rotary evaporator. Then, the powder was placed in an oven at 80℃ for 6h. After drying, it was passed through a 300-mesh sieve to obtain modified aluminum nitride powder.

[0038] 3) Preparation of photosensitive resin premix: Weigh 2.1g of ethyl 2-ethyleneoxyethoxyacrylate (VEEA), 3.3g of pentaerythritol tetraacrylate (PPTTA), and 2.3g of dioctyl phthalate (DOP), mix them, and ultrasonically disperse them for 10min to make them evenly mixed.

[0039] 4) Preparation of aluminum nitride ceramic slurry: Modified aluminum nitride powder was added to the photosensitive resin premix, along with 0.6g of KOS110 polymeric dispersant and 0.3g of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO) photoinitiator. The mixture was then homogenized using a high-speed homogenizer at a speed of 2500 r / min for 2 min.

[0040] 5) The 3D model of the ceramic part to be printed is layered using 3D software to determine the shape of each layer to be exposed and polymerized, and a printing control program is generated.

[0041] 6) Perform photopolymerization printing to obtain a ceramic blank.

[0042] 7) Clean the ceramic blank thoroughly.

[0043] 8) Perform debinding treatment on the ceramic blank. First, perform vacuum debinding: In a vacuum debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 2 hours, then raise the temperature to 350℃ and hold for 2 hours, and finally raise the temperature to 550℃ and hold for 6 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min. Then, perform air debinding: In an air debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 1 hour, then raise the temperature to 350℃ and hold for 1 hour, and finally raise the temperature to 450℃ and hold for 2 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min.

[0044] 9) Sinter the blank after debinding: Sinter at 1850℃ for 6 hours in a nitrogen atmosphere sintering furnace to obtain aluminum nitride ceramic.

[0045] Example 2

[0046] This embodiment provides an aluminum nitride ceramic slurry based on stereolithography and the aluminum nitride ceramic prepared from the slurry. The aluminum nitride ceramic slurry prepared in this embodiment has a solid content of 65 vol.%, uses 4 wt% KMT-3331 as the modifier, 5 wt% SmF3 as the sintering aid, and VEEA as the reactive diluent.

[0047] The specific preparation steps are as follows:

[0048] 1) Weigh 60g of aluminum nitride powder, place it in an oven, and dry it at 60℃ for 2 hours for later use.

[0049] 2) Preparation of modified aluminum nitride powder: The dried aluminum nitride powder was placed in 120g of anhydrous ethanol, and then 2.4g of KMT-3331, 3.2g of SmF3, and 120g of zirconia grinding balls were added. The material was ball-milled using a planetary ball mill at 350r / min for 6h. After ball milling, the anhydrous ethanol was removed by rotary evaporation, and then the powder was placed in an oven at 80℃ for 6h.

[0050] After drying, the powder is passed through a 300-mesh sieve to obtain modified aluminum nitride powder.

[0051] 3) Preparation of photosensitive resin premix: Weigh 2.7g of ethyl 2-ethyleneoxyethoxyacrylate (VEEA), 4.1g of pentaerythritol tetraacrylate (PPTTA), and 2.9g of dioctyl phthalate (DOP), mix them, and ultrasonically disperse them for 10min to make them evenly mixed.

[0052] 4) Preparation of aluminum nitride ceramic slurry: Modified aluminum nitride powder was added to the photosensitive resin premix, along with 0.6g of KOS110 polymeric dispersant and 0.2g of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO) photoinitiator. The mixture was homogenized using a high-speed homogenizer at a speed of 2500r / min for 2min.

[0053] 5) The 3D model of the ceramic part to be printed is layered using 3D software to determine the shape of each layer to be exposed and polymerized, and a printing control program is generated.

[0054] 6) Perform photopolymerization printing to obtain a ceramic blank.

[0055] 7) Clean the ceramic blank thoroughly.

[0056] 8) Perform debinding treatment on the ceramic blank. First, perform vacuum debinding: In a vacuum debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 2 hours, then raise the temperature to 350℃ and hold for 2 hours, and finally raise the temperature to 550℃ and hold for 6 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min. Then, perform air debinding: In an air debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 1 hour, then raise the temperature to 350℃ and hold for 1 hour, and finally raise the temperature to 450℃ and hold for 2 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min.

[0057] 9) Sinter the blank after debinding: Sinter at 1850℃ for 6 hours in a nitrogen atmosphere sintering furnace to obtain aluminum nitride ceramic.

[0058] Example 3

[0059] This embodiment provides an aluminum nitride ceramic slurry based on stereolithography and the aluminum nitride ceramic prepared from the slurry. The aluminum nitride ceramic slurry prepared in this embodiment has a solid content of 60 vol.%, and uses 3 wt% KMT-3331 as the modifier, 5 wt% SmF3 as the sintering aid, and VEEA as the reactive diluent.

[0060] The specific preparation steps are as follows:

[0061] 1) Weigh 60g of aluminum nitride powder, place it in an oven, and dry it at 60℃ for 2 hours for later use.

[0062] 2) Preparation of modified aluminum nitride powder: The dried aluminum nitride powder was placed in 120g of anhydrous ethanol, and then 1.8g of KMT-3331, 3.2g of SmF3 and 120g of zirconia ball milling balls were added. The above materials were ball milled by planetary ball mill at a speed of 350r / min for 6h. After ball milling, the anhydrous ethanol was removed by rotary evaporator. Then, the powder was placed in an oven at 80℃ for 6h. After drying, it was passed through a 300-mesh sieve to obtain modified aluminum nitride powder.

[0063] 3) Preparation of photosensitive resin premix: Weigh 3.4g of ethyl 2-ethyleneoxyethoxyacrylate (VEEA), 5.1g of pentaerythritol tetraacrylate (PPTTA), and 3.6g of dioctyl phthalate (DOP), mix them, and ultrasonically disperse them for 10min to make them evenly mixed.

[0064] 4) Preparation of aluminum nitride ceramic slurry: Add modified aluminum nitride powder to photosensitive resin premix, and add 0.6g of KOS110 polymeric dispersant and 0.24g of (2,4,6-trimethylbenzoyl)

[0065] Diphenylphosphine oxide (TPO) photoinitiator was mixed uniformly using a high-speed homogenizer at a speed of 2500 r / min for 2 min.

[0066] 5) The 3D model of the ceramic part to be printed is layered using 3D software to determine the shape of each layer to be exposed and polymerized, and a printing control program is generated.

[0067] 6) Perform photopolymerization printing to obtain a ceramic blank.

[0068] 7) Clean the ceramic blank thoroughly.

[0069] 8) Perform debinding treatment on the ceramic blank. First, perform vacuum debinding: In a vacuum debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 2 hours, then raise the temperature to 350℃ and hold for 2 hours, and finally raise the temperature to 550℃ and hold for 6 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min. Then, perform air debinding: In an air debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 1 hour, then raise the temperature to 350℃ and hold for 1 hour, and finally raise the temperature to 450℃ and hold for 2 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min.

[0070] 9) Sinter the blank after debinding: Sinter at 1850℃ for 6 hours in a nitrogen atmosphere sintering furnace to obtain aluminum nitride ceramic.

[0071] Example 4

[0072] This embodiment provides an aluminum nitride ceramic slurry based on stereolithography and the aluminum nitride ceramic prepared from the slurry. The aluminum nitride ceramic slurry prepared in this embodiment has a solid content of 55 vol.%, and the modifier used is 2 wt% KMT-3331, the sintering aid is 5 wt% SmF3, and the reactive diluent is VEEA.

[0073] The specific implementation steps are as follows:

[0074] 1) Weigh 60g of aluminum nitride powder, place it in an oven, and dry it at 60℃ for 2 hours for later use.

[0075] 2) Preparation of modified aluminum nitride powder: The dried aluminum nitride powder was placed in 120g of anhydrous ethanol, and then 1.2g of KMT-3331, 3.2g of SmF3, and 120g of zirconia grinding balls were added. The above materials were ball-milled by a planetary ball mill at a speed of 350r / min for 6h. After ball milling, the anhydrous ethanol was removed by rotary evaporation. Then, the powder was placed in an oven at 80℃ for 6h. After drying, it was passed through a 300-mesh sieve to obtain modified aluminum nitride powder.

[0076] 3) Preparation of photosensitive resin premix: Weigh 4.1g of ethyl 2-ethyleneoxyethoxyacrylate (VEEA), 6.2g of pentaerythritol tetraacrylate (PPTTA), and 4.4g of dioctyl phthalate (DOP), mix them, and ultrasonically disperse them for 10min to make them evenly mixed.

[0077] 4) Preparation of aluminum nitride ceramic slurry: Modified aluminum nitride powder was added to the photosensitive resin premix, along with 0.6g of KOS110 polymeric dispersant and 0.3g of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO) photoinitiator. The mixture was then homogenized using a high-speed homogenizer at a speed of 2500 r / min for 2 min.

[0078] 5) The 3D model of the ceramic part to be printed is layered using 3D software to determine the shape of each layer to be exposed and polymerized, and a printing control program is generated.

[0079] 6) Perform photopolymerization printing to obtain a ceramic blank.

[0080] 7) Clean the ceramic blank thoroughly.

[0081] 8) Perform debinding treatment on the ceramic blank. First, perform vacuum debinding: In a vacuum debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 2 hours, then raise the temperature to 350℃ and hold for 2 hours, and finally raise the temperature to 550℃ and hold for 6 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min. Then, perform air debinding: In an air debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 1 hour, then raise the temperature to 350℃ and hold for 1 hour, and finally raise the temperature to 450℃ and hold for 2 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min.

[0082] 9) Sinter the blank after debinding: Sinter at 1850℃ for 6 hours in a nitrogen atmosphere sintering furnace to obtain aluminum nitride ceramic.

[0083] Example 5

[0084] This embodiment provides an aluminum nitride ceramic slurry based on stereolithography and the aluminum nitride ceramic prepared from the slurry. The aluminum nitride ceramic slurry prepared in this embodiment has a solid content of 50 vol.%, and uses 1 wt% KMT-3331 as the modifier, 5 wt% SmF3 as the sintering aid, and VEEA as the reactive diluent.

[0085] The specific implementation steps are as follows:

[0086] 1) Weigh 60g of aluminum nitride powder, place it in an oven, and dry it at 60℃ for 2 hours for later use.

[0087] 2) Preparation of modified aluminum nitride powder: The dried aluminum nitride powder was placed in 120g of anhydrous ethanol, and then 0.6g of KMT-3331, 3.2g of SmF3 and 120g of zirconia ball milling balls were added. The above materials were ball milled by planetary ball mill at a speed of 350r / min for 6h. After ball milling, the anhydrous ethanol was removed by rotary evaporator. Then, the powder was placed in an oven at 80℃ for 6h. After drying, it was passed through a 300-mesh sieve to obtain modified aluminum nitride powder.

[0088] 3) Preparation of photosensitive resin premix: Weigh 5.0g of ethyl 2-ethyleneoxyethoxyacrylate (VEEA), 7.6g of pentaerythritol tetraacrylate (PPTTA), and 5.4g of dioctyl phthalate (DOP), mix them, and ultrasonically disperse them for 10min to make them evenly mixed.

[0089] 4) Preparation of aluminum nitride ceramic slurry: Add dried aluminum nitride powder to photosensitive resin premix, and add 0.6g of KOS110 polymeric dispersant and 0.37g of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO) photoinitiator. Mix evenly using a high-speed homogenizer at a speed of 2500r / min for 2min.

[0090] 5) The 3D model of the ceramic part to be printed is layered using 3D software to determine the shape of each layer to be exposed and polymerized, and a printing control program is generated.

[0091] 6) Perform photopolymerization printing to obtain a ceramic blank.

[0092] 7) Clean the ceramic blank thoroughly.

[0093] 8) Perform debinding treatment on the ceramic blank. First, perform vacuum debinding: In a vacuum debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 2 hours, then raise the temperature to 350℃ and hold for 2 hours, and finally raise the temperature to 550℃ and hold for 6 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min. Then, perform air debinding: In an air debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 1 hour, then raise the temperature to 350℃ and hold for 1 hour, and finally raise the temperature to 450℃ and hold for 2 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min.

[0094] 9) Sinter the blank after debinding: Sinter at 1850℃ for 6 hours in a nitrogen atmosphere sintering furnace to obtain aluminum nitride ceramic.

[0095] Comparative Example 1

[0096] This comparative example provides an aluminum nitride ceramic slurry and an aluminum nitride ceramic prepared from the slurry. The prepared aluminum nitride ceramic slurry has a solid content of 50 vol.%, uses 1 wt% KH570 as a modifier, 5 wt% Y2O3 as a sintering aid, and HDDA as an active diluent.

[0097] The specific implementation steps are as follows:

[0098] 1) Weigh 60g of aluminum nitride powder, place it in an oven, and dry it at 60℃ for 2 hours for later use.

[0099] 2) Preparation of modified aluminum nitride powder: The dried aluminum nitride powder was placed in 120g of anhydrous ethanol, and then 0.6g of KH570, 3.2g of Y2O3 and 120g of zirconia ball milling balls were added. The above materials were ball milled by planetary ball mill at a speed of 350r / min for 6h. After ball milling, the anhydrous ethanol was removed by rotary evaporation. Then, the powder was placed in an oven at 80℃ for 6h. After drying, it was passed through a 300-mesh sieve to obtain modified aluminum nitride powder.

[0100] 3) Preparation of photosensitive resin premix: Weigh 5.0g of 1,6-hexanediol diacrylate (HDDA), 7.6g of pentaerythritol tetraacrylate (PPTTA), and 5.4g of dioctyl phthalate (DOP), mix them, and ultrasonically disperse them for 10min to make them evenly mixed.

[0101] 4) Preparation of aluminum nitride ceramic slurry: Add dried aluminum nitride powder to photosensitive resin premix, and add 0.6g of KOS110 polymeric dispersant and 0.37g of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO) photoinitiator. Mix evenly using a high-speed homogenizer at a speed of 2500r / min for 2min.

[0102] 5) The 3D model of the ceramic part to be printed is layered using 3D software to determine the shape of each layer to be exposed and polymerized, and a printing control program is generated.

[0103] 6) Perform photopolymerization printing to obtain a ceramic blank.

[0104] 7) Clean the ceramic blank thoroughly.

[0105] 8) Perform debinding treatment on the ceramic blank. First, perform vacuum debinding: In a vacuum debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 2 hours, then raise the temperature to 350℃ and hold for 2 hours, and finally raise the temperature to 550℃ and hold for 6 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min. Then, perform air debinding: In an air debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 1 hour, then raise the temperature to 350℃ and hold for 1 hour, and finally raise the temperature to 450℃ and hold for 2 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min.

[0106] 9) Sinter the blank after debinding: Sinter at 1850℃ for 6 hours in a nitrogen atmosphere sintering furnace to obtain aluminum nitride ceramic.

[0107] Comparative Example 2

[0108] This comparative example provides an aluminum nitride ceramic slurry and an aluminum nitride ceramic prepared from the slurry. The prepared aluminum nitride ceramic slurry has a solid content of 50 vol.%, uses 1 wt% polyacrylic acid as a modifier, 5 wt% Y2O3 as a sintering aid, and HDDA as an active diluent.

[0109] The specific implementation steps are as follows:

[0110] 1) Weigh 60g of aluminum nitride powder, place it in an oven, and dry it at 60℃ for 2 hours for later use.

[0111] 2) Preparation of modified aluminum nitride powder: The dried aluminum nitride powder was placed in 120g of anhydrous ethanol, and then 0.6g of polyacrylic acid, 3.2g of Y2O3 and 120g of zirconia ball milling balls were added. The above materials were ball milled by planetary ball mill at a speed of 350r / min for 6h. After ball milling, the anhydrous ethanol was removed by rotary evaporation. Then, the powder was placed in an oven at 80℃ for 6h. After drying, it was passed through a 300-mesh sieve to obtain modified aluminum nitride powder.

[0112] 3) Preparation of photosensitive resin premix: Weigh 5.0g of 1,6-hexanediol diacrylate (HDDA), 7.6g of pentaerythritol tetraacrylate ethoxylate (PPTTA), and 5.4g of dioctyl phthalate (DOP).

[0113] Mix and ultrasonically disperse for 10 minutes to ensure uniform mixing.

[0114] 4) Preparation of aluminum nitride ceramic slurry: Add dried aluminum nitride powder to photosensitive resin premix, and add 0.6g of KOS110 polymeric dispersant and 0.37g of (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO) photoinitiator. Mix evenly using a high-speed homogenizer at a speed of 2500r / min for 2min.

[0115] 5) The 3D model of the ceramic part to be printed is layered using 3D software to determine the shape of each layer to be exposed and polymerized, and a printing control program is generated.

[0116] 6) Perform photopolymerization printing to obtain a ceramic blank.

[0117] 7) Clean the ceramic blank thoroughly.

[0118] 8) Perform debinding treatment on the ceramic blank. First, perform vacuum debinding: In a vacuum debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 2 hours, then raise the temperature to 350℃ and hold for 2 hours, and finally raise the temperature to 550℃ and hold for 6 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min. Then, perform air debinding: In an air debinding furnace, first raise the temperature from room temperature to 160℃ and hold for 1 hour, then raise the temperature to 350℃ and hold for 1 hour, and finally raise the temperature to 450℃ and hold for 2 hours before cooling to room temperature with the furnace; the heating rate is 2℃ / min.

[0119] 9) Sinter the blank after debinding: Sinter at 1850℃ for 6 hours in a nitrogen atmosphere sintering furnace to obtain aluminum nitride ceramic.

[0120] Comparative Example 3

[0121] This comparative example uses a commercially available aluminum nitride substrate manufactured using a casting process from Esenda Corporation.

[0122] The ceramic slurry and ceramic products prepared in the above embodiments and comparative examples were subjected to relevant performance tests, and the results are shown in Table 1 below.

[0123] Table 1. Performance results of ceramic slurries and ceramic products prepared in the examples and comparative examples.

[0124]

[0125] Note: The viscosity of the slurry is based on a shear rate of 100 s. -1 The value measured at that time is expressed in Pa·s.

[0126] The rheological properties test results of the slurries prepared in Example 5 and Comparative Example 2 are shown in the figure. Figure 1 .

[0127] Depend on Figure 1As shown in Table 1, at a solid content of 50 vol.%, the aluminum nitride ceramic slurry prepared in Example 5 using VEEA dilution and acrylic block copolymer modification exhibits significantly lower viscosity and better rheological properties compared to the slurry in Comparative Example 2. In other words, the effect achieved by combining acrylic block copolymer modification with diluent 2-ethyleneoxyethoxyethyl acrylate (VEEA) in this invention is superior to that achieved by combining silane coupling agent KH570, polyacrylic acid modification, and 1,6-hexanediol diacrylate (HDDA). Furthermore, the aluminum nitride substrates prepared using the slurry provided by this invention, especially those prepared with a solid content between 60 and 70 vol.%, show better performance than the commercially available aluminum nitride substrates prepared by tape casting in Comparative Example 3. This demonstrates that the aluminum nitride ceramic slurry based on stereolithography provided by this invention can achieve stereolithography at high solid contents of 50–70 vol.%, expanding the application of stereolithography-cured aluminum nitride ceramics and enabling the preparation of high-performance aluminum nitride ceramics.

[0128] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0129] The above description describes specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing aluminum nitride ceramic slurry based on stereolithography, characterized in that, Includes the following steps: S1. Preparation of modified aluminum nitride powder: Take 85-95 parts of aluminum nitride powder, 1-10 parts of sintering aid, and 0.1-5 parts of acrylic block copolymer by mass, ball mill and mix, dry and sieve to obtain modified powder; S2. Preparation of photosensitive resin premix: Take 14-76 parts by weight of reactive diluent, 14-76 parts by weight of polyfunctional acrylate monomer, and 5-30 parts by weight of plasticizer, and disperse and mix them by ultrasonication to obtain photosensitive resin premix. S3. Preparation of aluminum nitride ceramic slurry: By volume percentage, take 50-70 vol.% of the modified powder, 27-47 vol.% of the photosensitive resin premix, 0.25-3 vol.% of the photoinitiator, and 0.25-3 vol.% of the polymeric dispersant, and mix them at high speed to obtain aluminum nitride ceramic slurry. The aluminum nitride ceramic slurry has a solid content of 50-70 vol.%; the acrylic block copolymer is one or more of BZ-2431 and KMT-3331; the reactive diluent is ethyl 2-ethyleneoxyethoxyacrylate; and the sintering aid is SmF3.

2. The method for preparing aluminum nitride ceramic slurry based on stereolithography as described in claim 1, characterized in that, The multifunctional acrylate monomers are one or more of tripropylene glycol diacrylate, trimethylolpropane triacrylate, and pentaerythritol tetraacrylate.

3. The method for preparing aluminum nitride ceramic slurry based on stereolithography as described in claim 1, characterized in that, The plasticizer is either dioctyl phthalate or dibutyl phthalate.

4. The method for preparing aluminum nitride ceramic slurry based on stereolithography as described in claim 1, characterized in that, The photoinitiator is selected from (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, and the polymeric dispersant is selected from one or more of BYK-110, BYK-111, and KOS110.

5. An aluminum nitride ceramic slurry, characterized in that, It is prepared by the method for preparing aluminum nitride ceramic slurry based on stereolithography as described in any one of claims 1-4.

6. A method for preparing aluminum nitride ceramics, characterized in that, Using the aluminum nitride ceramic slurry as described in claim 5 as raw material, photocuring molding is performed to prepare a green body, and the prepared green body is degreased and sintered to obtain aluminum nitride ceramic; wherein, the solid content of the aluminum nitride ceramic slurry is 50-70 vol..

7. An aluminum nitride ceramic, characterized in that, It is prepared by the method described in claim 6.

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