Photocurable silicon oxynitride ceramic slurry, preparation and method for preparing complex structure porous ceramic

Abstract

The application discloses a photocuring silicon oxynitride ceramic slurry, a preparation method and a complex structure porous ceramic preparation method. The slurry comprises modified ceramic mixed powder obtained by mixing ceramic powder and a surface modifier and a dispersing agent and a premixed liquid. The mixed ceramic powder comprises ceramic powder and a sintering aid. The ceramic powder is silicon oxynitride powder. The sintering aid is yttrium oxide powder and aluminum oxide powder. The premixed liquid comprises a mixture and a photoinitiator. The mixture is a mixed liquid of bisphenol A type difunctional epoxy acrylate resin, difunctional aliphatic polyurethane acrylate resin, isobornyl methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene. The photoinitiator is 2,4,6-trimethylbenzoyl phenyl phosphonate. The complex structure porous ceramic preparation method using the slurry comprises printing, debinding and sintering processes. The application realizes photocuring forming of silicon oxynitride ceramic complex parts and preparation of complex structure ceramics.

Description

Technical Field

[0001] This invention belongs to the field of silicon oxynitride ceramic technology, specifically relating to a photocurable silicon oxynitride ceramic slurry, its preparation, and a method for preparing complex porous ceramic structures. Background Technology

[0002] Silicon oxynitride ceramics possess excellent thermal shock resistance, good mechanical properties, and good oxidation resistance, making them a promising high-temperature ceramic material. Silicon oxynitride materials have a similar crystal structure to silicon nitride, meaning they exhibit similar mechanical properties. However, compared to silicon nitride, silicon oxynitride exhibits better thermal shock resistance, a lower dielectric constant, and a lower dielectric loss angle, making it one of the few high-performance materials capable of replacing silicon nitride ceramics in the aerospace industry. Furthermore, due to its diverse chemical bonds and structural diversity, silicon oxynitride also demonstrates better oxidation resistance than silicon nitride, silicon oxynitride, and other refractories. In addition, silicon oxynitride ceramics possess excellent thermal shock resistance, especially porous silicon oxynitride ceramics, which have a low coefficient of thermal expansion (α = 1.26 × 10⁻⁶). -6 ℃ -1 b = 3.89 × 10 -6 ℃ -1 c = 3.99 × 10 -6 ℃ -1 In terms of chemical stability, silicon oxynitride has excellent corrosion resistance in environments with a large amount of acid and molten non-ferrous metals, so silicon oxynitride is very promising to become a high-performance material for use in the field of refractory materials.

[0003] The excellent properties exhibited by silicon oxynitride make it a promising high-temperature structural and functional material for manufacturing hot-end components of aero-engines. In the field of porous silicon oxynitride ceramics, Li adopted a technical solution of using Al2O3-Y2O3 sintering aid to prepare porous Si2N2O / Si3N4 composite material by gel casting method. The test results show that the porous Si2N2O / Si3N4 material has excellent comprehensive performance and the flexural strength can reach 230MPa (Li SQ, Pei YC, Yu CQ, et al. Mechanical and dielectric properties of porous Si2N2O–Si3N4 initu composites[J]. Ceramics International, 2009, 35(5): 1851-1854. DOI: 10.1016 / j.ceramint.2008.10.021.). However, due to the non-uniform and complex structure of the hot-end components of aero-engines, high requirements are placed on manufacturing precision and processes. Furthermore, the harsh working environment of these components demands stringent requirements on the uniformity, stability, reliability, high-temperature performance, and mechanical properties of the manufactured products, which traditional molding processes can no longer meet. Meanwhile, the continuous development of ceramic photopolymerization (DLP) technology enables the fabrication of complex structural and functional ceramic prototypes. Therefore, exploring the process of molding complex Si2N2O ceramics using DLP technology is of significant strategic importance for the development of aero-engines with higher thrust-to-weight ratios.

[0004] However, current research on silicon oxynitride ceramics mainly focuses on the reaction sintering of Si2N2O ceramics and traditional forming and processing techniques, and there is a lack of research on the DLP preparation process of silicon oxynitride ceramics. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a photocurable silicon oxynitride ceramic slurry, preparation method and complex structure porous ceramic preparation method, which can realize the photocuring forming of complex silicon oxynitride ceramic parts and the preparation of complex structure ceramics.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] A photocurable silicon oxynitride ceramic slurry comprises a modified ceramic mixed powder obtained by ball milling mixed ceramic powder, surface modifier, and dispersant, and a premixed liquid; the mass of the premixed liquid is 85-99% of the modified ceramic mixed powder.

[0008] The mixed ceramic powder consists of ceramic powder and sintering aids; the ceramic powder is silicon oxynitride powder with AR purity; the sintering aids are yttrium oxide powder and alumina powder with AR purity, with a mass of 4-6% and 2-4% of the ceramic powder mass, respectively.

[0009] The premix includes mixture A and a photoinitiator; mixture A is a mixture of bisphenol A-type difunctional epoxy acrylate resin, difunctional aliphatic polyurethane acrylate resin, isoborneol methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, with a mass ratio of (5-7):(3-5):(26-28):(8-10):(26-28):(26-28); the photoinitiator is 2,4,6-trimethylbenzoylphenylphosphonate (TPO, C 22 H 21 O2P) accounts for 4-6% of the mass of mixture A.

[0010] The silicon oxynitride powder of purity AR, the sintering aid yttrium oxide powder, and the alumina powder, after ball milling, have a median particle size of 5-7 μm.

[0011] The surface modifier is silane coupling agent KH570, and its mass is 3-5% of the ceramic powder mass;

[0012] The dispersant is dehydrated sorbitol fatty acid, and its mass is 1-5% of the ceramic powder mass.

[0013] A method for preparing a photocurable silicon oxynitride ceramic slurry includes the following steps:

[0014] (1) Select silicon oxynitride powder, yttrium oxide powder, and alumina powder with a purity of AR and prepare a mixed ceramic powder in a mass ratio of 100:(4-6):(2-4). Add 3-5% by weight of the ceramic powder surface modifier silane coupling agent KH570 and 1-5% by weight of the ceramic powder dispersant sorbitol fatty acid. Use anhydrous ethanol as the ball milling medium and stir the mixture evenly in a homogenizer. During the ball milling modification process, add agate grinding balls, the amount of which is 100-300% of the ceramic powder mass. The ball milling modification time is 12-24 hours to obtain the modified ceramic mixed powder.

[0015] (2) Mixture A is formed by mixing bisphenol A type-difunctional epoxy acrylate resin, difunctional-aliphatic polyurethane acrylate resin, isoborneol methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene in a mass ratio of (5-7):(3-5):(26-28):(8-10):(26-28):(26-28); a photoinitiator is added to mixture A to obtain a premixed solution. The photoinitiator is the free radical photoinitiator 2,4,6-trimethylbenzoylphenylphosphonate, accounting for 4-6% of the mass of mixture A.

[0016] (3) Add the modified ceramic mixed powder to the premixed liquid in batches. The mass of the premixed liquid is 85-99% of the mass of the modified ceramic mixed powder. While defoaming in the homogenizer, stir and mix evenly to obtain silicon oxynitride ceramic slurry.

[0017] A method for preparing complex-structured porous ceramics using a photocurable silicon oxynitride ceramic slurry includes the following steps:

[0018] (1) Printing process: Laser exposure power is 27-31mW / cm 2 The layer-by-layer exposure time is 1-5s, the layer thickness is 20-100μm, and the scraper speed is 10-30° / s.

[0019] (2) Degreasing process: The degreasing atmosphere is argon. The following temperature regime is determined according to the TG-DSC curve. The heating range is 25-750℃, of which the heating rate between 300-500℃ is 0.1-0.5℃ / min. The temperature is held at 300℃, 400℃ and 500℃ for 2-6h, 2-6h and 2-6h respectively. The heating rate in the remaining stages is 0.1-0.5℃ / min. The temperature is held at 50℃ for 1-4h, and then cooled with the furnace. After degreasing, the furnace is pre-fired, and the temperature is raised to 800℃ at a rate of 0.5-1.5℃ / min, and held for 0.5-2.5h.

[0020] The decarbonization process uses air as the atmosphere and a heating range of 25-800℃. The heating rate is 1-5℃ / min between 300-500℃ and 2-8℃ / min in the remaining stages. The furnace is held at 150℃, 500℃ and 800℃ for 1-3h, 1-3h and 1-3h respectively, and then cooled with the furnace.

[0021] (3) Sintering process: The sintering atmosphere is nitrogen, the pressure is 1-9 MPa, the heating range is 25-1650℃, the heating rate is 2-8℃ / min, and the temperature is held at 1600℃ and 1650℃ for 0.5-2.5h and 1-3h respectively, and then cooled with the furnace.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) This invention discloses a method for preparing photocurable silicon oxynitride ceramic slurry. Since this invention uses silicon oxynitride powder with a purity of AR as the ceramic powder raw material, the median particle size after ball milling is 5-7 μm. The prepared ceramic slurry has a suitable viscosity, which ensures the stability during the printing process. Therefore, it has the advantages of preparing ceramic samples with uniform composition and good interlayer bonding.

[0024] (2) Since the present invention uses bisphenol A type-difunctional epoxy acrylate resin, difunctional-aliphatic polyurethane acrylate resin, isobornyl methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene as photocurable prepolymer and active monomer, it ensures that the ceramic slurry has sufficient single-layer curing depth, and at the same time can significantly reduce the viscosity of the slurry and improve the stability of the slurry. Mixture A is prepared in a certain proportion, so the mixture has the advantages of low viscosity, high curing depth and high stability.

[0025] (3) Because this invention uses silane coupling agent KH570 to modify the surface of ceramic powder, the hydrophilic groups of the modifier can dehydrate and condense with the hydroxyl groups on the surface of the powder, and the lipophilic ends can bind well with the photosensitive resin, thereby improving the compatibility between the powder and the resin and increasing the solid content and stability of the ceramic slurry; sorbitol fatty acid is used as a dispersant, which can form a coating film on the surface of silicon oxynitride ceramic powder to prevent powder agglomeration and flocculation. Therefore, the prepared ceramic slurry has the advantages of low viscosity, high solid content, high curing depth, and high stability.

[0026] (4) Since the present invention determines the degreasing process based on the TG-DSC curve, the degreasing is divided into two steps: argon degreasing and air decarburization, thereby ensuring that the degreased green billet is free from defects such as cracks and internal stress. The degreasing atmosphere is argon, and the heating range is 25-750℃. The heating rate between 300-500℃ is 0.2℃ / min. The temperature is held at 300℃, 400℃ and 500℃ for 3h, 4h and 4h respectively. The heating rate in the remaining stages is 0.5℃ / min. The temperature is held at 50℃ for 1-4h, and then cooled with the furnace. After degreasing, the billet is pre-fired in the furnace, heated to 800℃ at a rate of 1℃ / min, and held for 1.5h. The decarbonization atmosphere was air, and the heating range was 25-800℃. The heating rate was 2℃ / min between 300-500℃, and 5℃ / min for the remaining stages. The samples were held at 150℃, 500℃, and 800℃ for 1h, 2h, and 1h respectively, and then cooled in the furnace. Therefore, the degreased ceramic samples have the advantages of a smooth surface and no cracking or deformation.

[0027] (5) Because the present invention adopts a suitable sintering regime, the sintering atmosphere is nitrogen, the pressure is 5MPa, the heating range is 25-1650℃, the heating rate is 5℃ / min, and the temperature is held at 1600℃ and 1650℃ for 1h and 2h respectively, and then cooled with the furnace, the sintered ceramic sample has the advantages of dense structure and excellent comprehensive performance.

[0028] (6) This invention discloses a method for preparing a photocurable silicon oxynitride ceramic slurry. First, silicon oxynitride ceramic powder, yttrium oxide powder, and alumina powder are mixed with anhydrous ethanol in a certain proportion. Agate balls, KH570, and dehydrated sorbitol fatty acids are added for ball milling modification, simultaneously dispersing agglomerates and improving the dispersion performance of the ceramic powder. After ball milling the premixed liquid according to the component proportions, the dried modified powder is mixed with the premixed liquid. The mixed slurry is then subjected to multi-stage vacuum degassing and high-speed stirring using a homogenizer, ensuring thorough mixing of the modified powder and the resin premixed liquid, resulting in a stable and homogeneous photocurable silicon oxynitride ceramic slurry. The slurry is then printed to form a green body, which is then degreased and sintered to finally obtain a silicon oxynitride ceramic with a complex structure. Attached Figure Description

[0029] Figure 1 (a) is an unmodified slurry; (b) is a photocurable silicon oxynitride ceramic slurry prepared in Example 1 of the present invention; (c) is a photocurable test piece of Example 1.

[0030] Figure 2 The test strip is printed from a photocurable silicon oxynitride ceramic slurry prepared in Example 1.

[0031] Figure 3 The ceramic sample prepared in Example 1 was printed, degreased, and sintered. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings.

[0033] Example 1: A photocurable silicon oxynitride ceramic slurry, comprising modified ceramic mixed powder obtained by ball milling mixed ceramic powder, surface modifier, and dispersant, and a premixed liquid; the mass of the premixed liquid is 85% of the modified ceramic mixed powder;

[0034] The mixed ceramic powder consists of ceramic powder and sintering aids; the ceramic powder is silicon oxynitride powder with AR purity; the sintering aids are yttrium oxide powder and alumina powder with AR purity, accounting for 4% and 2% of the mass of the ceramic powder, respectively.

[0035] The premix comprises mixture A and a photoinitiator; mixture A is a mixture of bisphenol A-type difunctional epoxy acrylate resin, difunctional aliphatic polyurethane acrylate resin, isoborneol methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, with a mass ratio of 5:3:26:8:26:26; the photoinitiator is 2,4,6-trimethylbenzoylphenylphosphonate (TPO, C 22 H 21 O2P) accounts for 4% of the mass of mixture A.

[0036] The silicon oxynitride powder of purity AR, yttrium oxide powder and alumina powder of sintering aids, after ball milling, have a median particle size of 5 μm.

[0037] The surface modifier is silane coupling agent KH570, and its mass is 3% of the ceramic powder mass;

[0038] The dispersant is dehydrated sorbitol fatty acid, and its mass is 1% of the mass of the ceramic powder.

[0039] A method for preparing a photocurable silicon oxynitride ceramic slurry includes the following steps:

[0040] (1) Select silicon oxynitride powder, yttrium oxide powder and alumina powder with purity AR and prepare a mixed ceramic powder in a mass ratio of 100:4:2. Add 3% by mass of surface modifier silane coupling agent KH570 and 1% by mass of dispersant sorbitol fatty acid to the mixture. Use anhydrous ethanol as the ball milling medium and stir the mixture evenly in a homogenizer. During the ball milling modification process, add agate grinding balls, the amount of agate grinding balls being 100% of the mass of the ceramic powder. The ball milling modification time is 12 hours. The modified ceramic mixed powder is obtained.

[0041] (2) Mix bisphenol A type-difunctional epoxy acrylate resin, difunctional-aliphatic polyurethane acrylate resin, isobornyl methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene in a mass ratio of 5:3:26:8:26:26 to form mixture A; add a photoinitiator to mixture A to obtain a premixed solution. The photoinitiator is the free radical photoinitiator 2,4,6-trimethylbenzoylphenylphosphonate, accounting for 4% of the mass of mixture A;

[0042] (3) Add the modified ceramic mixed powder to the premixed liquid in batches. The mass of the premixed liquid is 85% of the mass of the modified ceramic mixed powder. While defoaming in the homogenizer, stir and mix evenly to obtain silicon oxynitride ceramic slurry.

[0043] A method for preparing complex-structured porous ceramics using a photocurable silicon oxynitride ceramic slurry includes the following steps:

[0044] (1) Printing process: Laser exposure power is 27mW / cm 2 The layer-by-layer exposure time is 1 second, the layer thickness is 20 μm, and the scraper speed is 10° / s.

[0045] (2) Degreasing process: The degreasing atmosphere is argon. The following temperature regime is determined according to the TG-DSC curve. The heating range is 25-750℃, of which the heating rate between 300-5000℃ is 0.1℃ / min. The temperature is held at 300℃, 400℃ and 500℃ for 2h, 2h and 2h respectively. The heating rate in the remaining stages is 0.1℃ / min. The temperature is held at 50℃ for 1h and cooled with the furnace. After degreasing, the furnace is pre-fired, and the temperature is raised to 800℃ at a rate of 0.5℃ / min and held for 0.5h.

[0046] The decarbonization process uses air as the atmosphere and a heating range of 25-800℃. The heating rate is 1℃ / min between 300-500℃ and 2℃ / min in the remaining stages. The furnace is then held at 150℃, 500℃ and 800℃ for 1h, 1h and 1h respectively, and then cooled with the furnace.

[0047] (3) Sintering process: The sintering atmosphere is nitrogen, the pressure is 1MPa, the heating range is 25-1650℃, the heating rate is 2℃ / min, and the temperature is held at 1600℃ and 1650℃ for 0.5h and 1h respectively, and then cooled with the furnace.

[0048] The silicon oxynitride ceramic slurry prepared in this embodiment has a smooth and fluid surface, good flow properties, high precision in printing the green body, and no surface defects; it has little shrinkage and no cracks after degreasing; and the sintered ceramic sample has no surface defects and no obvious deformation.

[0049] Figure 1 The images show the silicon oxynitride ceramic slurry prepared in Example 1 and the corresponding photocuring test sheet. (a) is the slurry without surface modification, (b) is the slurry prepared in this example, and (c) is the photocuring test sheet. From the comparison of (a) and (b), it can be seen that the silicon oxynitride ceramic slurry after surface modification in this example has no obvious lateral diffusion and warping deformation during the printing process, has good dimensional accuracy, and the curing depth is greater than 60 μm when the exposure time is 3s, which meets the printing requirements.

[0050] Figure 2 The figure shows a test strip prepared from the silicon oxynitride ceramic slurry in Example 1. As can be seen from the figure, there is no obvious layering along the Z-axis, indicating that the silicon oxynitride ceramic slurry has a uniform and stable composition, good rheological properties, no lateral diffusion or warping deformation, and high dimensional accuracy.

[0051] Figure 3 The ceramic sample prepared by the silicon oxynitride ceramic slurry in Example 1 shows that the sample has a clear outline, high precision in the formation of structural holes, and no breakage. This indicates that the silicon oxynitride ceramic slurry in this example has good rheological and curing properties, and there is no obvious shrinkage or diffusion during the printing process. It can be used for photocuring of silicon oxynitride ceramics, and the debinding and sintering process is beneficial to the precision manufacturing of silicon oxynitride ceramics.

[0052] Example 2: A photocurable silicon oxynitride ceramic slurry, comprising modified ceramic mixed powder obtained by ball milling mixed ceramic powder, surface modifier, and dispersant, and a premixed liquid; the mass of the premixed liquid is 92% of the modified ceramic mixed powder;

[0053] The mixed ceramic powder consists of ceramic powder and sintering aids; the ceramic powder is silicon oxynitride powder with AR purity; the sintering aids are yttrium oxide powder and alumina powder with AR purity, accounting for 5% and 3% of the mass of the ceramic powder, respectively.

[0054] The premix comprises mixture A and a photoinitiator; mixture A is a mixture of bisphenol A-type difunctional epoxy acrylate resin, difunctional aliphatic polyurethane acrylate resin, isoborneol methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, with a mass ratio of 6:4:27:9:27:27; the photoinitiator is 2,4,6-trimethylbenzoylphenylphosphonate (TPO, C 22 H 21 O2P) accounts for 5% of the mass of mixture A.

[0055] The silicon oxynitride powder of purity AR, yttrium oxide powder and alumina powder of sintering aids, after ball milling, have a median particle size of 6 μm.

[0056] The surface modifier is silane coupling agent KH570, and its mass is 4% of the ceramic powder mass;

[0057] The dispersant is dehydrated sorbitol fatty acid, and its mass is 3% of the mass of the ceramic powder.

[0058] A method for preparing a photocurable silicon oxynitride ceramic slurry includes the following steps:

[0059] (1) Select silicon oxynitride powder, yttrium oxide powder and alumina powder with purity AR and prepare a mixed ceramic powder in a mass ratio of 100:5:3. Add 4% by mass of surface modifier silane coupling agent KH570 and 3% by mass of dispersant sorbitol fatty acid to the mixture. Use anhydrous ethanol as the ball milling medium and stir the mixture evenly in a homogenizer. During the ball milling modification process, add agate grinding balls, the amount of agate grinding balls being 200% of the mass of ceramic powder, and the ball milling modification time being 18 hours. The modified ceramic mixed powder is obtained.

[0060] (2) Mix bisphenol A type-difunctional epoxy acrylate resin, difunctional-aliphatic polyurethane acrylate resin, isobornyl methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene in a mass ratio of 6:4:27:9:27:27 to form mixture A; add a photoinitiator to mixture A to obtain a premixed solution. The photoinitiator is the free radical photoinitiator 2,4,6-trimethylbenzoylphenylphosphonate, accounting for 5% of the mass of mixture A;

[0061] (3) Add the modified ceramic mixed powder to the premixed liquid in batches. The mass of the premixed liquid is 92% of the mass of the modified ceramic mixed powder. While defoaming in the homogenizer, stir and mix evenly to obtain silicon oxynitride ceramic slurry.

[0062] A method for preparing complex-structured porous ceramics using a photocurable silicon oxynitride ceramic slurry includes the following steps:

[0063] (1) Printing process: Laser exposure power is 29mW / cm 2 The layer-by-layer exposure time was 3 seconds, the layer thickness was 60 μm, and the scraper speed was 20° / s.

[0064] (2) Degreasing process: The degreasing atmosphere is argon. The following temperature regime is determined according to the TG-DSC curve. The heating range is 25-750℃, of which the heating rate between 300-5000℃ is 0.3℃ / min. The temperature is held at 300℃, 400℃ and 500℃ for 4h, 4h and 4h respectively. The heating rate in the remaining stages is 0.3℃ / min. The temperature is held at 50℃ for 2.5h. The furnace is cooled. After degreasing, the furnace is pre-fired, and the temperature is raised to 800℃ at a rate of 1℃ / min. The holding time is 1.5h.

[0065] The decarbonization process uses air as the atmosphere and the heating range is 25-800℃. The heating rate is 3℃ / min between 300-500℃ and 4℃ / min in the remaining stages. The furnace is then held at 150℃, 500℃ and 800℃ for 2h, 2h and 2h respectively, and then cooled with the furnace.

[0066] (3) Sintering process: The sintering atmosphere is nitrogen, the pressure is 5MPa, the heating range is 25-1650℃, the heating rate is 5℃ / min, and the temperature is held at 1600℃ and 1650℃ for 1.5h and 2h respectively, and then cooled with the furnace.

[0067] The beneficial effects of this embodiment are similar to those of Embodiment 1.

[0068] Example 3: A photocurable silicon oxynitride ceramic slurry, comprising modified ceramic mixed powder obtained by ball milling mixed ceramic powder, surface modifier, and dispersant, and a premixed liquid; the mass of the premixed liquid is 99% of the modified ceramic mixed powder;

[0069] The mixed ceramic powder consists of ceramic powder and sintering aids; the ceramic powder is silicon oxynitride powder with AR purity; the sintering aids are yttrium oxide powder and alumina powder with AR purity, accounting for 6% and 4% of the ceramic powder mass, respectively.

[0070] The premix comprises mixture A and a photoinitiator; mixture A is a mixture of bisphenol A-type difunctional epoxy acrylate resin, difunctional aliphatic polyurethane acrylate resin, isoborneol methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, with a mass ratio of 7:5:28:10:28:28; the photoinitiator is 2,4,6-trimethylbenzoylphenylphosphonate (TPO, C 22 H 21 O2P) accounts for 6% of the mass of mixture A.

[0071] The silicon oxynitride powder of purity AR, yttrium oxide powder and alumina powder of sintering aids, after ball milling, have a median particle size of 7 μm.

[0072] The surface modifier is silane coupling agent KH570, and its mass is 5% of the ceramic powder mass;

[0073] The dispersant is dehydrated sorbitol fatty acid, and its mass is 5% of the ceramic powder mass.

[0074] A method for preparing a photocurable silicon oxynitride ceramic slurry includes the following steps:

[0075] (1) Select silicon oxynitride powder, yttrium oxide powder and alumina powder with purity AR and prepare a mixed ceramic powder in a mass ratio of 100:6:4. Add 5% by mass of surface modifier silane coupling agent KH570 and 5% by mass of dispersant sorbitol fatty acid to the mixture. Use anhydrous ethanol as the ball milling medium and stir the mixture evenly in a homogenizer. During the ball milling modification process, add agate grinding balls at a mass of 300% of the ceramic powder. The ball milling modification time is 24 hours. The modified ceramic mixed powder is obtained.

[0076] (2) Mix bisphenol A type-difunctional epoxy acrylate resin, difunctional-aliphatic polyurethane acrylate resin, isobornyl methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene in a mass ratio of 7:5:28:10:28:28 to form mixture A; add a photoinitiator to mixture A to obtain a premixed solution. The photoinitiator is the free radical photoinitiator 2,4,6-trimethylbenzoylphenylphosphonate, accounting for 6% of the mass of mixture A;

[0077] (3) Add the modified ceramic mixed powder to the premixed liquid in batches. The mass of the premixed liquid is 99% of the mass of the modified ceramic mixed powder. While defoaming in the homogenizer, stir and mix evenly to obtain silicon oxynitride ceramic slurry.

[0078] A method for preparing complex-structured porous ceramics using a photocurable silicon oxynitride ceramic slurry includes the following steps:

[0079] Printing process: Laser exposure power is 31mW / cm 2 The layer-by-layer exposure time was 5 seconds, the layer thickness was 100 μm, and the scraper speed was 30° / s.

[0080] (2) Degreasing process: The degreasing atmosphere is argon. The following temperature regime is determined according to the TG-DSC curve. The heating range is 25-750℃, of which the heating rate between 300-5000℃ is 0.5℃ / min. The temperature is held at 300℃, 400℃ and 500℃ for 6h, 6h and 6h respectively. The heating rate in the remaining stages is 0.5℃ / min. The temperature is held at 50℃ for 4h and cooled with the furnace. After degreasing, the furnace is pre-fired, and the temperature is raised to 800℃ at a rate of 1.5℃ / min and held for 2.5h.

[0081] The decarbonization process uses air as the atmosphere and a heating range of 25-800℃. The heating rate is 5℃ / min between 300-500℃ and 8℃ in other stages. The furnace is then cooled.

[0082] (3) Sintering process: The sintering atmosphere is nitrogen, the pressure is 9MPa, the heating range is 25-1650℃, the heating rate is 8℃ / min, and the temperature is held at 1600℃ and 1650℃ for 2.5h and 3h respectively, and then cooled with the furnace.

[0083] The beneficial effects of this embodiment are similar to those of Embodiment 1.

[0084] Example 4: A photocurable silicon oxynitride ceramic slurry, comprising modified ceramic mixed powder obtained by ball milling mixed ceramic powder, surface modifier, and dispersant, and a premixed liquid; the mass of the premixed liquid is 90% of the modified ceramic mixed powder;

[0085] The mixed ceramic powder consists of ceramic powder and sintering aids; the ceramic powder is silicon oxynitride powder with AR purity; the sintering aids are yttrium oxide powder and alumina powder with AR purity, with a mass of 5.5% and 3.5% of the ceramic powder mass, respectively.

[0086] The premix comprises mixture A and a photoinitiator; mixture A is a mixture of bisphenol A-type difunctional epoxy acrylate resin, difunctional aliphatic polyurethane acrylate resin, isoborneol methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, with a mass ratio of 7:4:26:9:26:28; the photoinitiator is 2,4,6-trimethylbenzoylphenylphosphonate (TPO, C 22 H 21 O2P) accounts for 5.5% of the mass of mixture A.

[0087] The silicon oxynitride powder of purity AR, the sintering aids yttrium oxide powder and alumina powder, after ball milling, have a median particle size of 6.5 μm.

[0088] The surface modifier is silane coupling agent KH570, and its mass is 4% of the ceramic powder mass;

[0089] The dispersant is dehydrated sorbitol fatty acid, and its mass is 4% of the ceramic powder mass.

[0090] A method for preparing a photocurable silicon oxynitride ceramic slurry includes the following steps:

[0091] (1) Select silicon oxynitride powder, yttrium oxide powder and alumina powder with purity AR and prepare a mixed ceramic powder in a mass ratio of 100:6:2. Add 5% by mass of surface modifier silane coupling agent KH570 and 5% by mass of dispersant sorbitol fatty acid to the mixture. Use anhydrous ethanol as the ball milling medium and stir the mixture evenly in a homogenizer. During the ball milling modification process, add agate grinding balls at a mass of 250% of the ceramic powder and ball mill for 20 hours to obtain the modified ceramic mixed powder.

[0092] (2) Mix bisphenol A type-difunctional epoxy acrylate resin, difunctional-aliphatic polyurethane acrylate resin, isobornyl methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene in a mass ratio of 7:4:26:9:26:28 to form mixture A; add a photoinitiator to mixture A to obtain a premixed solution. The photoinitiator is the free radical photoinitiator 2,4,6-trimethylbenzoylphenylphosphonate, accounting for 5.5% of the mass of mixture A;

[0093] (3) Add the modified ceramic mixed powder to the premixed liquid in batches. The mass of the premixed liquid is 90% of the mass of the modified ceramic mixed powder. While defoaming in the homogenizer, stir and mix evenly to obtain silicon oxynitride ceramic slurry.

[0094] A method for preparing complex-structured porous ceramics using a photocurable silicon oxynitride ceramic slurry includes the following steps:

[0095] Printing process: Laser exposure power is 30mW / cm 2 The layer-by-layer exposure time was 4 seconds, the layer thickness was 800 μm, and the squeegee speed was 25° / s.

[0096] (2) Degreasing process: The degreasing atmosphere is argon. The following temperature regime is determined according to the TG-DSC curve. The heating range is 25-750℃, of which the heating rate between 300-5000℃ is 0.4℃ / min. The temperature is held at 300℃, 400℃ and 500℃ for 3h, 5h and 3h respectively. The heating rate in the remaining stages is 0.4℃ / min. The temperature is held at 50℃ for 3h and cooled with the furnace. After degreasing, the furnace is pre-fired, and the temperature is raised to 800℃ at a rate of 0.9℃ / min and held for 2h.

[0097] The decarbonization process uses air as the atmosphere and a heating range of 25-800℃. The heating rate is 4℃ / min between 300-500℃ and 6℃ / min in the remaining stages. The furnace is held at 150℃, 500℃ and 800℃ for 1.5h, 1.7h and 2.5h respectively, and then cooled with the furnace.

[0098] (3) Sintering process: The sintering atmosphere is nitrogen, the pressure is 7MPa, the heating range is 25-1650℃, the heating rate is 6℃ / min, and the temperature is held at 1600℃ and 1650℃ for 2h and 2.5h respectively, and then cooled with the furnace.

[0099] The beneficial effects of this embodiment are similar to those of Embodiment 1.

Claims

1. A photocurable silicon oxynitride ceramic slurry, characterized in that: It includes a modified ceramic mixed powder obtained by ball milling mixed ceramic powder, surface modifier, and dispersant, as well as a premixed liquid; the mass of the premixed liquid is 85-99% of the modified ceramic mixed powder. The mixed ceramic powder consists of ceramic powder and sintering aids; the ceramic powder is silicon oxynitride powder with AR purity; the sintering aids are yttrium oxide powder and alumina powder with AR purity, accounting for 4-6% and 2-4% of the ceramic powder mass, respectively. The premix includes mixture A and a photoinitiator; mixture A is a mixture of bisphenol A-type difunctional epoxy acrylate resin, difunctional aliphatic polyurethane acrylate resin, isoborneol methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, with a mass ratio of (5-7):(3-5):(26-28):(8-10):(26-28):(26-28); the photoinitiator is 2,4,6-trimethylbenzoylphenylphosphonate (TPO, C 22 H 21 O2P accounts for 4-6% of the mass of mixture A.

2. The photocurable silicon oxynitride ceramic slurry according to claim 1, characterized in that: The silicon oxynitride powder of purity AR, the sintering aids yttrium oxide powder and alumina powder, after ball milling, have a median particle size of 5-7 μm.

3. The photocurable silicon oxynitride ceramic slurry according to claim 1, characterized in that: The surface modifier is silane coupling agent KH570, and its mass is 3-5% of the ceramic powder mass.

4. The photocurable silicon oxynitride ceramic slurry according to claim 1, characterized in that: The dispersant is dehydrated sorbitol fatty acid, and its mass is 1-5% of the mass of the ceramic powder.

5. A method for preparing a photocurable silicon oxynitride ceramic slurry according to any one of claims 1-4, characterized in that, Includes the following steps: (1) Select silicon oxynitride powder, yttrium oxide powder and alumina powder with purity AR and prepare a mixed ceramic powder in a mass ratio of 100:(4-6):(2-4). Add 3-5% of the surface modifier silane coupling agent KH570 and 1-5% of the dispersant sorbitol fatty acid to the ceramic powder. Use anhydrous ethanol as the ball milling medium and stir the mixture evenly in a homogenizer. Add agate grinding balls during the ball milling modification process. The amount of agate grinding balls added is 100-300% of the mass of the ceramic powder. The ball milling modification time is 12-24h. The modified ceramic mixed powder is obtained. (2) Mix bisphenol A type-difunctional epoxy acrylate resin, difunctional-aliphatic polyurethane acrylate resin, isoborneol methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene in a mass ratio of (5-7):(3-5):(26-28):(8-10):(26-28):(26-28) to form mixture A; add a photoinitiator to mixture A to obtain a premixed solution. The photoinitiator is the free radical photoinitiator 2,4,6-trimethylbenzoylphenylphosphonate, accounting for 4-6% of the mass of mixture A. (3) Add the modified ceramic mixed powder to the premixed liquid in batches. The mass of the premixed liquid is 85-99% of the mass of the modified ceramic mixed powder. While defoaming in the homogenizer, stir and mix evenly to obtain silicon oxynitride ceramic slurry.

6. A method for preparing complex-structured porous ceramics using a photocurable silicon oxynitride ceramic slurry as described in claim 5, characterized in that, Includes the following steps: (1) Printing process: Laser exposure power is 27-31mW / cm 2 The layer-by-layer exposure time is 1-5s, the layer thickness is 20-100μm, and the scraper speed is 10-30° / s. (2) Degreasing process: The degreasing atmosphere is argon. The following temperature regime is determined according to the TG-DSC curve. The heating range is 25-750℃, of which the heating rate between 300-500℃ is 0.1-0.5℃ / min. The temperature is held at 300℃, 400℃ and 500℃ for 2-6h, 2-6h and 2-6h respectively. The heating rate in the remaining stages is 0.1-0.5℃ / min. The temperature is held at 50℃ for 1-4h. The furnace is cooled. After degreasing, the furnace is pre-fired. The temperature is raised to 800℃ at a rate of 0.5-1.5℃ / min and held for 0.5-2.5h. The decarbonization process uses air as the atmosphere and a heating range of 25-800℃. The heating rate is 1-5℃ / min between 300-500℃ and 2-8℃ / min in the remaining stages. The furnace is held at 150℃, 500℃ and 800℃ for 1-3h, 1-3h and 1-3h respectively, and then cooled with the furnace. (3) Sintering process: The sintering atmosphere is nitrogen, the pressure is 1-9 MPa, the heating range is 25-1650℃, the heating rate is 2-8℃ / min, and the temperature is held at 1600℃ and 1650℃ for 0.5-2.5h and 1-3h respectively, and then cooled with the furnace.

7. A photocurable silicon oxynitride ceramic slurry, characterized in that, It includes a modified ceramic mixed powder obtained by ball milling mixed ceramic powder, surface modifier, and dispersant, as well as a premixed liquid; the mass of the premixed liquid is 85% of the modified ceramic mixed powder. The mixed ceramic powder consists of ceramic powder and sintering aids; the ceramic powder is silicon oxynitride powder with AR purity; the sintering aids are yttrium oxide powder and alumina powder with AR purity, accounting for 4% and 2% of the ceramic powder mass, respectively. The premix comprises mixture A and a photoinitiator; mixture A is a mixture of bisphenol A-type difunctional epoxy acrylate resin, difunctional aliphatic polyurethane acrylate resin, isoborneol methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, with a mass ratio of 5:3:26:8:26:26; the photoinitiator is 2,4,6-trimethylbenzoylphenylphosphonate (TPO, C 22 H 21 O2P), accounting for 4% of the mass of mixture A; The silicon oxynitride powder of purity AR, yttrium oxide powder and alumina powder of sintering aids, after ball milling, have a median particle size of 5 μm. The surface modifier is silane coupling agent KH570, and its mass is 3% of the ceramic powder mass; The dispersant is dehydrated sorbitol fatty acid, and its mass is 1% of the mass of the ceramic powder.

8. The method for preparing a photocurable silicon oxynitride ceramic slurry according to claim 7, characterized in that, Includes the following steps: (1) Select silicon oxynitride powder, yttrium oxide powder and alumina powder with purity AR and prepare a mixed ceramic powder in a mass ratio of 100:4:

2. Add 3% by mass of surface modifier silane coupling agent KH570 and 1% by mass of dispersant sorbitol fatty acid to the mixture. Use anhydrous ethanol as the ball milling medium and stir the mixture evenly in a homogenizer. Add agate grinding balls during the ball milling modification process. The amount of agate grinding balls added is 200% of the mass of ceramic powder. The ball milling modification time is 12h. The modified ceramic mixed powder is obtained. (2) Mix bisphenol A type-difunctional epoxy acrylate resin, difunctional-aliphatic polyurethane acrylate resin, isobornyl methacrylate, trimethylolpropane triacrylate, dipentaerythritol hexaacrylate, and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene in a mass ratio of 5:3:26:8:26:26 to form mixture A; add a photoinitiator to mixture A to obtain a premixed solution. The photoinitiator is the free radical photoinitiator 2,4,6-trimethylbenzoylphenylphosphonate, accounting for 4% of the mass of mixture A. (3) Add the modified ceramic mixed powder to the premixed liquid in batches. The mass of the premixed liquid is 85% of the mass of the modified ceramic mixed powder. While defoaming in the homogenizer, stir and mix evenly to obtain silicon oxynitride ceramic slurry.

9. A method for preparing complex-structured porous ceramics using a photocurable silicon oxynitride ceramic slurry as described in claim 8, characterized in that, Includes the following steps: (1) Printing process: Laser exposure power is 27mW / cm 2 The layer-by-layer exposure time is 1 second, the layer thickness is 20 μm, and the scraper speed is 10° / s. (2) Degreasing process: The degreasing atmosphere is argon. The following temperature regime is determined according to the TG-DSC curve. The heating range is 25-750℃, of which the heating rate between 300-500℃ is 0.1℃ / min. The temperature is held at 300℃, 400℃ and 500℃ for 2h, 2h and 2h respectively. The heating rate in the remaining stages is 0.1℃ / min. The temperature is held at 50℃ for 1h and cooled with the furnace. After degreasing, the furnace is pre-fired, and the temperature is raised to 800℃ at a rate of 0.5℃ / min and held for 0.5h. The decarbonization process uses air as the atmosphere and a heating range of 25-800℃. The heating rate is 1℃ / min between 300-500℃ and 2℃ / min in the remaining stages. The furnace is then held at 150℃, 500℃ and 800℃ for 1h, 1h and 1h respectively, and then cooled with the furnace. (3) Sintering process: The sintering atmosphere is nitrogen, the pressure is 5MPa, the heating range is 25-1650℃, the heating rate is 2℃ / min, and the temperature is held at 1600℃ and 1650℃ for 0.5h and 1h respectively, and then cooled with the furnace.

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