Silicon carbide ceramic slurry, silicon carbide ceramic material and preparation method and application thereof

Abstract

The invention provides silicon carbide ceramic slurry, a silicon carbide ceramic material and a preparation method and application thereof, and relates to the technical field of additive manufacturing. The silicon carbide ceramic slurry is composed of silicon carbide powder, a carbon source, a photosensitive active monomer, a photosensitive active diluent, a photoinitiator, a dispersant, a leveling agent and an anti-settling agent. The carbon source comprises but is not limited to one or more of phenolic resin, diamond, carbon nanotubes, short carbon fibers and cellulose. The silicon carbide ceramic preform with high residual carbon rate is obtained by adding a carbon source or compounding a plurality of carbon sources, so that more secondary silicon carbide is generated in the reaction sintering step, and the silicon carbide ceramic material with good performance is finally obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic additive manufacturing, and in particular to a silicon carbide ceramic slurry, a silicon carbide ceramic material, and a preparation method and application thereof. Background Art

[0002] Silicon carbide ceramic materials have excellent mechanical properties, high-temperature resistance, thermal conductivity, and chemical stability. In recent years, silicon carbide ceramics have been widely used in traditional industrial fields and emerging high-tech fields such as semiconductors, nuclear energy, and national defense. As the requirements for material performance in specific application scenarios continue to increase, the demand for complex silicon carbide ceramics in components such as space mirrors, engine guide vanes, and combustion chambers is becoming increasingly urgent. However, the inherent high hardness and brittleness of silicon carbide ceramics not only pose challenges to mechanical processing, but also limit their large-scale application. Traditional mechanical processing methods often cannot meet the demand for high-precision processing of complex-shaped silicon carbide ceramics, and are prone to problems such as cracks and fractures during the processing process. At the same time, the processing efficiency is insufficient and the yield rate is low. Therefore, it has become a consensus in academia and industry to develop near-net-shape forming technology to address the challenges brought by silicon carbide precision processing. Near-net-shape forming technology can produce silicon carbide ceramic components with complex shapes and excellent performance at a lower cost, thus meeting the needs of various application scenarios.

[0003] The photocuring process for silicon carbide ceramics involves uniformly dispersing silicon carbide powder in a photosensitive resin system. UV radiation from a photocuring device triggers the polymerization of the photosensitive resin, resulting in a near-net-shape silicon carbide blank. The preform is pyrolyzed, and then subjected to silicon infiltration and reaction sintering to create the reaction-sintered silicon carbide ceramic product.

[0004] However, the preparation methods of silicon carbide ceramics provided in the prior art have the problems of complicated procedures, high processing costs, long processing time, and limited improvement in mechanical properties. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the first object of the present invention is to provide a silicon carbide ceramic slurry that can be used to prepare reaction-sintered silicon carbide with high mechanical properties; the second object of the present invention is to provide an application of the silicon carbide ceramic slurry.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a silicon carbide ceramic slurry. The slurry comprises the following raw materials in parts by mass: 30 to 80 parts of silicon carbide powder, 20 to 50 parts of a carbon source, 20 to 40 parts of a photoactive monomer, 20 to 40 parts of a photoactive diluent, a photoinitiator, a dispersant, a leveling agent, and an anti-settling agent. The photoinitiator is added in an amount of 1% to 5% of the total mass of the photoactive monomer and the photoactive diluent, the dispersant is added in an amount of 0.5% to 3% of the mass of the silicon carbide powder, the leveling agent is added in an amount of 0.5% to 2% of the mass of the silicon carbide powder, and the anti-settling agent is added in an amount of 0.5% to 2% of the mass of the silicon carbide powder.

[0008] Furthermore, the carbon source includes but is not limited to one or more of phenolic resin, diamond, carbon nanotube, chopped carbon fiber, and cellulose.

[0009] Furthermore, the particle size of the silicon carbide powder is in the range of 0.02 to 100 μm. Preferably, the particle size of the silicon carbide powder is in the range of 1 to 50 μm and / or 0.02 to 0.5 μm.

[0010] The photosensitive active monomer includes but is not limited to one or more of ethoxylated trimethylolpropane triacrylate, ethoxylated pentaerythritol tetraacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, epoxy soybean oil acrylate, aliphatic polyurethane acrylate, modified polyurethane acrylate, aromatic polyurethane acrylate, and bisphenol A epoxy acrylate, preferably ethoxylated pentaerythritol tetraacrylate.

[0011] The photosensitive active diluent includes but is not limited to one or more of 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, trimethylolpropane ethoxy triacrylate, ethoxypentaerythritol tetraacrylate, propoxylated neopentyl glycol diacrylate, tripropylene glycol diacrylate, cyclotrimethylolpropane formal acrylate, isobornyl acrylate, hydroxyethyl acrylate, and hydroxyethyl methacrylate, preferably 1,6-hexanediol diacrylate.

[0012] The photoinitiator includes but is not limited to one or more of diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide, 2-isopropylthioxanthone, 2,4,6-trimethylbenzoyl-di (p-tolyl) phosphine oxide, bis (1- (2,4-difluorophenyl) -3-pyrrolyl) titanocene, preferably diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide.

[0013] The dispersant includes but is not limited to one or more of BYK-108, BYK-180, KOS163, KOS110, KOS2400, 17000, and K-271, preferably BYK-108.

[0014] The leveling agent includes but is not limited to one or more of BYK-323, BYK-333, BYK-354, H421, LS3003, DH-4072, AKN-1181, and AKN-1035, preferably BYK-323.

[0015] The anti-settling agent includes but is not limited to one or more of KMT-4542, DH-6900, BYK-410, K-635, and AKN-7020, preferably KMT-4542.

[0016] The present invention also provides a method for preparing the silicon carbide ceramic slurry according to the above-mentioned method, which can be performed by any of the following two methods, specifically comprising the following steps:

[0017] Method 1: Silicon carbide powder and a carbon source are mixed and ball-milled for 1 to 24 hours, and then a photosensitive active monomer, a photosensitive active diluent, a photoinitiator, a dispersant, a leveling agent, and an anti-settling agent are added and mixed with a vacuum non-contact stirrer for 1 to 10 minutes to obtain the silicon carbide ceramic slurry; the solid phase volume fraction of the obtained silicon carbide ceramic slurry is controlled to be above 40%, and the viscosity is controlled to be 1 to 10 Pa·s;

[0018] Method 2: Silicon carbide powder, a carbon source, a photosensitive active monomer, a photosensitive active diluent, a photoinitiator, a dispersant, a leveling agent, and an anti-settling agent are mixed and ball-milled for 1 to 48 hours to obtain the silicon carbide ceramic slurry; the solid phase volume fraction of the obtained silicon carbide ceramic slurry is controlled to be above 40%, and the viscosity is controlled to be 1 to 10 Pa·s.

[0019] The present invention also provides a use of the above-mentioned silicon carbide ceramic slurry in preparing a silicon carbide ceramic material.

[0020] The present invention also provides a method for preparing a silicon carbide ceramic material, which comprises the following steps: constructing a geometric model, slicing the geometric model according to a single layer thickness of 10 μm to 100 μm to obtain a data file, and importing the data file into a 3D printer; preparing the silicon carbide ceramic slurry as described above; using a 3D printer in combination with the data file to print and photocuring the silicon carbide ceramic slurry, with a single layer exposure time of 5 to 360 seconds, to obtain a porous silicon carbide ceramic green body; after the porous silicon carbide ceramic green body is fully cleaned and dried, pyrolysis treatment is carried out under inert gas protection or vacuum conditions, with a heating rate of 1 to 10°C / min, a pyrolysis temperature of 600 to 1500°C, and a holding time of 10 to 300 minutes to obtain a silicon carbide ceramic preform; and densifying the silicon carbide ceramic preform under vacuum conditions by high-temperature silicon infiltration reaction sintering at a temperature of 1450 to 2000°C and a holding time of 10 minutes to 6 hours to obtain the silicon carbide ceramic material.

[0021] Among them, the steps of constructing a geometric model, slicing the geometric model according to a single layer thickness of 10μm to 100μm, obtaining a data file, and importing the data file into a 3D printer specifically include: using three-dimensional modeling software to construct a geometric figure, converting it into a data file recognizable by a 3D printer such as OBJ or STL, slicing the geometric model according to a single layer thickness of 10μm to 100μm, obtaining a data file, and importing the data file into a 3D printer.

[0022] The present invention also provides a silicon carbide ceramic material prepared according to the above-mentioned method for preparing the silicon carbide ceramic material.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention provides a silicon carbide ceramic slurry, a silicon carbide ceramic material, and a preparation method and application thereof. The method for preparing the silicon carbide ceramic material regulates the type and content of the carbon source in the ceramic slurry so that the solid content and curing depth of the ceramic slurry are increased while having a suitable viscosity. For example, after adding small-particle diamond, the viscosity of the slurry is significantly reduced, and after adding cellulose, the curing depth of the slurry is significantly increased; the carbon source is sintered and densified in the subsequent siliconization reaction. This method does not require the powder to be modified, crushed, or other treatments, which greatly saves molding time. It has the advantages of high solid content, high curing depth, low viscosity, and high sintered body density, and the resulting silicon carbide ceramic has excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art; obviously, the drawings described below are some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 A flow chart of a method for preparing a silicon carbide ceramic slurry provided by the present invention;

[0027] Figure 2 The silicon carbide ceramic slurry of Example 1 of the present invention;

[0028] Figure 3 is the viscosity characteristic curve of the silicon carbide ceramic slurry of Example 1 of the present invention;

[0029] Figure 4 The silicon carbide ceramic green body of Example 1 of the present invention;

[0030] Figure 5 The silicon carbide ceramic preform of Example 1 of the present invention;

[0031] Figure 6 The silicon carbide ceramic material of Example 1 of the present invention;

[0032] Figure 7 This is a microstructure image of the silicon carbide ceramic material of Example 1 of the present invention;

[0033] Figure 8 This is the porous silicon carbide ceramic green body of Example 1 of the present invention. DETAILED DESCRIPTION

[0034] The inventors have discovered that the mechanical properties of reaction-sintered silicon carbide sintered bodies are closely affected by the carbon source in the preform. The carbon source in the silicon carbide photocuring process comes primarily from two sources: cracking products from the photosensitive resin, and additional carbon sources added to the slurry. To expand the application range of reaction-sintered silicon carbide ceramics, the most critical issue is to introduce a carbon source into the photocuring slurry while precisely controlling the carbon morphology, carbon content, and carbon distribution in the preform to enhance the mechanical properties of the sintered body.

[0035] Chinese patent document CN119100797A discloses a method for obtaining a silicon carbide powder with a composite structure by subjecting submicron green silicon carbide to a series of processes including pelletizing, solidification, air flow crushing, modification, heat treatment, and fumigation bleaching. During the paste mixing process, the composite structure of the silicon carbide powder does not disintegrate, and the modified liquid phase layer is not easily detached. This overcomes the problems of fine-particle silicon carbide powder severely absorbing light sources and being difficult to print, and the low sintering activity and low green density of coarse-particle powder.

[0036] Chinese patent document CN114436658A discloses a method for obtaining a light-cured silicon carbide ceramic slurry by modifying silicon carbide powder to obtain a modified silicon carbide powder coated with silicon dioxide, then mixing the modified silicon carbide powder, a photosensitive resin, and a dispersant, and then ball-milling the mixture. While this patent document addresses, to a certain extent, the issues of slurry fluidity during photocuring and insufficient curing depth due to the silicon carbide powder's severe absorption of light sources, the process of crushing and modifying the silicon carbide powder is complex, resulting in high processing costs and a long processing time. Furthermore, without the addition of an additional carbon source to the slurry, the resulting secondary silicon carbide during sintering is relatively small, resulting in limited improvements in mechanical properties.

[0037] In view of this, the present invention provides a slurry for photocuring 3D printing reaction-sintered silicon carbide ceramics and its application, wherein the slurry includes silicon carbide powder, a carbon source, a photosensitive active monomer, a photosensitive active diluent, a photoinitiator, a dispersant, a leveling agent, and an anti-settling agent.

[0038] The present invention provides a silicon carbide ceramic slurry. The slurry comprises the following raw materials in parts by mass: 30 to 80 parts of silicon carbide powder, 20 to 50 parts of a carbon source, 20 to 40 parts of a photoactive monomer, 20 to 40 parts of a photoactive diluent, a photoinitiator, a dispersant, a leveling agent, and an anti-settling agent. The photoinitiator is added in an amount of 1% to 5% of the total mass of the photoactive monomer and the photoactive diluent, the dispersant is added in an amount of 0.5% to 3% of the mass of the silicon carbide powder, the leveling agent is added in an amount of 0.5% to 2% of the mass of the silicon carbide powder, and the anti-settling agent is added in an amount of 0.5% to 2% of the mass of the silicon carbide powder.

[0039] In some specific embodiments of the present invention, the resin monomer includes a photosensitive active monomer and a photosensitive active diluent.

[0040] In some specific embodiments of the present invention, the carbon source includes but is not limited to one or more of phenolic resin, diamond, carbon nanotube, chopped carbon fiber, and cellulose.

[0041] In some specific embodiments of the present invention, the photosensitive active monomer includes but is not limited to one or more of ethoxylated trimethylolpropane triacrylate, ethoxylated pentaerythritol tetraacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, epoxy soybean oil acrylate, aliphatic polyurethane acrylate, modified polyurethane acrylate, aromatic polyurethane acrylate, and bisphenol A epoxy acrylate.

[0042] In some specific embodiments of the present invention, the photosensitive active diluent includes but is not limited to one or more of 1,6-hexanediol diacrylate (HDDA), trimethylolpropane triacrylate (TMPTA), trimethylolpropane ethoxy triacrylate (TMP3EOTA), ethoxypentaerythritol tetraacrylate (PPTTA), propoxylated neopentyl glycol diacrylate (NPG2PODA), tripropylene glycol diacrylate (TPGDA), cyclotrimethylolpropane formal acrylate (CTFA), isobornyl acrylate (IBOA), hydroxyethyl acrylate (HEA), and hydroxyethyl methacrylate (HEMA).

[0043] In some specific embodiments of the present invention, the photoinitiator can be selected from one or more of diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO), phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide (819), 2-isopropylthioxanthone, 2,4,6-trimethylbenzoyl-di (p-tolyl) phosphine oxide, and bis (1- (2,4-difluorophenyl) -3-pyrrolyl) titanocene.

[0044] In some specific embodiments of the present invention, the dispersant includes but is not limited to one or more of BYK-108, BYK-180, KOS163, KOS110, KOS2400, 17000, and K-271.

[0045] In some specific embodiments of the present invention, the leveling agent includes but is not limited to one or more of BYK-323, BYK-333, BYK-354, H421, LS3003, DH-4072, AKN-1181, and AKN-1035.

[0046] In some specific embodiments of the present invention, the anti-settling agent includes but is not limited to one or more of KMT-4542, DH-6900, BYK-410, K-635, and AKN-7020.

[0047] The present invention provides a method for preparing the silicon carbide ceramic slurry as described above, Figure 1 As shown, the preparation method can be performed by any of the following two methods, which specifically includes the following steps:

[0048] Method 1: Silicon carbide powder and a carbon source are mixed and ball-milled for 1 to 24 hours, and then a photosensitive active monomer, a photosensitive active diluent, a photoinitiator, a dispersant, a leveling agent, and an anti-settling agent are added and mixed with a vacuum non-contact stirrer for 1 to 10 minutes to obtain the silicon carbide ceramic slurry; the solid phase volume fraction of the obtained silicon carbide ceramic slurry is controlled to be above 40%, and the viscosity is controlled to be 1 to 10 Pa·s;

[0049] Method 2: Silicon carbide powder, a carbon source, a photosensitive active monomer, a photosensitive active diluent, a photoinitiator, a dispersant, a leveling agent, and an anti-settling agent are mixed and ball-milled for 1 to 48 hours to obtain the silicon carbide ceramic slurry; the solid phase volume fraction of the obtained silicon carbide ceramic slurry is controlled to be above 40%, and the viscosity is controlled to be 1 to 10 Pa·s.

[0050] The present invention is described in detail below with reference to specific embodiments.

[0051] Example 1

[0052] A method for preparing a silicon carbide ceramic slurry and a silicon carbide ceramic material, comprising:

[0053] S1: 70 parts of silicon carbide powder with a particle size of 10 μm and 30 parts of diamond with a particle size of 3.5 μm were selected; the two powders were mixed and ball-milled in a planetary ball mill at 300 rpm for 3 h. The mixed ceramic powder after ball milling was set aside for later use.

[0054] S2: Select 50 parts of aliphatic polyurethane acrylate and HDDA as resin monomers, and mix them in a mass ratio of 1:1; select TPO as a photoinitiator, the mass of which is 1% of the resin monomer; select KOS110 as a dispersant, the mass of which is 1% of the mixed ceramic powder in S1; select BYK-323 as a leveling agent, the mass of which is 1% of the mixed ceramic powder in S1; select K-635 as an anti-settling agent, the mass of which is 1% of the mixed ceramic powder in S1; 100 parts of the mixed ceramic powder obtained in step 1 are mixed with the resin monomer, photoinitiator, dispersant, leveling agent and anti-settling agent, and homogenize them in a non-contact stirrer at a speed of 1200r / min for 3min, and finally prepare a reaction-sintered silicon carbide ceramic slurry for photocuring 3D printing, such as Figure 2 The obtained slurry has good fluidity and its viscosity is 5.9Pa·s (30s -1 ),like Figure 3 As shown in the viscosity characteristic curve, the solidification depth of the obtained slurry flow is 55μm.

[0055] S3: The model in the modeling software is imported into the slicing software, sliced at a thickness of 40 μm, and then the sliced data file is imported into the DLP light-curing printer for printing; the printing parameters of the printer are a wavelength of 405 nm and a curing time of 45 s; after the printing is completed, a porous silicon carbide ceramic green body is obtained, such as Figure 4 As shown, the green body is intact without obvious layers or cracks.

[0056] S4: Degreasing the porous silicon carbide ceramic green body obtained in S3 in high-purity nitrogen (nitrogen gas volume fraction ≥ 99.999%), heating rate 6 ° C / min, treatment temperature 800 ° C, holding time 120 min, to obtain a silicon carbide ceramic preform, such as Figure 5 As shown, at this time the resin has been converted into residual carbon, and the green body has changed from gray to black.

[0057] S5: The formed preform and a pre-arranged amount of polycrystalline silicon particles (the mass of which is 60% of the mass of the preform) are used as silicon sources, and high-temperature siliconization reaction sintering is carried out under vacuum conditions at a temperature of 1700°C and a holding time of 1 hour to obtain a silicon carbide ceramic material, such as Figure 6 As shown in the figure, the surface of the material is bright silver. Figure 7 As shown in the figure, a large number of pores in the preform after pyrolysis disappear after sintering by high-temperature siliconization reaction, and the structure is densified.

[0058] The properties of the silicon carbide ceramic slurry of Example 1 and the mechanical properties of the silicon carbide ceramic material formed by photocuring are shown in Table 1.

[0059] The porous silicon carbide ceramic green body prepared by photocuring 3D printing of the silicon carbide ceramic slurry of Example 1 is as follows Figure 8 As shown, it is explained that the silicon carbide ceramic slurry and the method for preparing the silicon carbide ceramic material can be used to prepare silicon carbide ceramic materials with complex structures.

[0060] Example 2

[0061] A method for preparing a silicon carbide ceramic slurry and a silicon carbide ceramic material, comprising:

[0062] S1: 70 parts of silicon carbide powder with a particle size of 10 μm and 30 parts of phenolic resin (residual carbon rate of 45%) were selected; the two powders were mixed and ball-milled in a planetary ball mill at 300 rpm for 6 hours. The mixed ceramic powder after ball milling was set aside for later use.

[0063] S2: Select 40 parts of epoxy soybean oil acrylate and PPTTA as resin monomers, and mix them in a mass ratio of 1:1; select TPO as a photoinitiator, the mass of which is 1% of the resin monomer; select BYK-180 as a dispersant, the mass of which is 1% of the mixed ceramic powder in S1; select LS3003 as a leveling agent, the mass of which is 1% of the mixed ceramic powder in S1; select AKN-7020 as an anti-settling agent, the mass of which is 1% of the mixed ceramic powder in S1; 100 parts of the mixed ceramic powder obtained in step 1 are mixed with the resin monomer, photoinitiator, dispersant, leveling agent and anti-settling agent, and homogenize them in a non-contact stirrer at a speed of 1400r / min for 3 minutes, and finally prepare a reaction-sintered silicon carbide ceramic slurry for photocuring 3D printing. The obtained slurry has a curing depth of 50μm and a viscosity of 6.8Pa·s(30s -1 ).

[0064] S3: The model in the modeling software is imported into the slicing software, sliced at a thickness of 30 μm, and then the sliced data file is imported into the DLP light-curing printer for printing; the printing parameters of the printer are a wavelength of 405 nm and a curing time of 45 seconds; after printing, a porous silicon carbide ceramic green body is obtained.

[0065] S4: Degreasing the porous silicon carbide ceramic green body obtained in S3 under the protection of high-purity nitrogen (nitrogen gas volume fraction ≥ 99.999%), with a heating rate of 3°C / min, a treatment temperature of 800°C, and a holding time of 120 min to obtain a silicon carbide ceramic preform.

[0066] S5: The formed preform and a pre-arranged appropriate amount of polycrystalline silicon particles (the mass of which is 60% of the mass of the preform) are used as silicon sources, and high-temperature siliconization reaction sintering is carried out under vacuum conditions at a temperature of 1600° C. and a holding time of 3 hours to obtain a silicon carbide ceramic material.

[0067] The properties of the ceramic slurry of Example 2 and the mechanical properties of the photocured silicon carbide ceramic are shown in Table 1.

[0068] Example 3

[0069] A method for preparing a silicon carbide ceramic slurry and a silicon carbide ceramic material, comprising:

[0070] S1: 65 parts of silicon carbide powder with a particle size of 10 μm and 35 parts of cellulose (residual carbon rate of 40%) were selected; the two powders were mixed and ball-milled in a planetary ball mill at 400 rpm for 3 hours. The mixed ceramic powder after ball milling was set aside for later use.

[0071] S2: Select polyethylene glycol dimethacrylate and TMP3EOTA as 60 parts of resin monomers and mix them in a mass ratio of 1:1; select 819 as a photoinitiator, the mass of which is 1% of the resin monomer; select KOS110 as a dispersant, the mass of which is 1% of the mixed ceramic powder in S1; select BYK-323 as a leveling agent, the mass of which is 1% of the mixed ceramic powder in S1; select DH-6900 as an anti-settling agent, the mass of which is 1% of the mixed ceramic powder in S1; 100 parts of the mixed ceramic powder obtained in step 1 are mixed with the resin monomer, photoinitiator, dispersant, leveling agent and anti-settling agent, and homogenized in a non-contact stirrer at a speed of 1200r / min for 3 minutes, and finally prepare a reaction-sintered silicon carbide ceramic slurry for photocuring 3D printing. The obtained slurry has a curing depth of 65μm and a viscosity of 6.1Pa·s(30s -1 ).

[0072] S3: The model in the modeling software is imported into the slicing software, sliced at a thickness of 30 μm, and then the sliced data file is imported into the DLP light-curing printer for printing; the printing parameters of the printer are a wavelength of 405 nm and a curing time of 30 seconds; after printing, a porous silicon carbide ceramic green body is obtained.

[0073] S4: Degreasing the porous silicon carbide ceramic green body obtained in S3 under the protection of high-purity argon (argon gas volume fraction ≥ 99.99%), with a heating rate of 2.7°C / min, a treatment temperature of 900°C, and a holding time of 90 min to obtain a silicon carbide ceramic preform.

[0074] S5: The formed preform and a pre-arranged appropriate amount of polycrystalline silicon particles (the mass of which is 70% of the mass of the preform) are used as silicon sources, and high-temperature siliconization reaction sintering is carried out under vacuum conditions at a temperature of 1800° C. and a holding time of 2 hours to obtain a silicon carbide ceramic material.

[0075] The properties of the ceramic slurry of Example 3 and the mechanical properties of the photocured silicon carbide ceramic are shown in Table 1.

[0076] Example 4

[0077] A method for preparing a silicon carbide ceramic slurry and a silicon carbide ceramic material, comprising:

[0078] S1: 60 parts of silicon carbide powder with a particle size of 10 μm and 40 parts of chopped carbon fiber powder with a diameter of 1 μm were selected; the two powders were mixed and ball-milled in a planetary ball mill at 500 rpm for 3 hours, and the mixed ceramic powder after ball milling was set aside for later use.

[0079] S2: Select 40 parts of NPG2PODA and bisphenol A epoxy acrylate as resin monomers, and mix them in a mass ratio of 1:1; select 2-isopropylthioxanthone as a photoinitiator, the mass of which is 1% of the resin monomer; select 17000 as a dispersant, the mass of which is 1% of the mixed ceramic powder in S1; select AKN-1181 as a leveling agent, the mass of which is 1% of the mixed ceramic powder in S1; select DH-6900 as an anti-settling agent, the mass of which is 1% of the mixed ceramic powder in S1; 100 parts of the mixed ceramic powder obtained in step 1 are mixed with the resin monomer, photoinitiator, dispersant, leveling agent and anti-settling agent, and homogenize them in a non-contact stirrer at a speed of 1200r / min for 3 minutes, and finally prepare a reaction-sintered silicon carbide ceramic slurry for photocuring 3D printing. The obtained slurry has a curing depth of 45μm and a viscosity of 6.3Pa·s(30s -1 ).

[0080] S3: The model in the modeling software is imported into the slicing software, sliced at a thickness of 30 μm, and then the sliced data file is imported into the DLP light-curing printer for printing; the printing parameters of the printer are a wavelength of 405 nm and a curing time of 60 seconds; after printing, a porous silicon carbide ceramic green body is obtained.

[0081] S4: Degreasing the porous silicon carbide ceramic green body obtained in S3 under the protection of high-purity nitrogen (nitrogen gas volume fraction ≥ 99.999%), with a heating rate of 2.1°C / min, a treatment temperature of 800°C, and a holding time of 120 min to obtain a silicon carbide ceramic preform.

[0082] S5: The formed preform and a pre-arranged appropriate amount of polycrystalline silicon particles (the mass of which is 80% of the mass of the preform) are used as silicon sources, and high-temperature siliconization reaction sintering is carried out under vacuum conditions at a temperature of 1700° C. and a holding time of 0.5 h to obtain a silicon carbide ceramic material.

[0083] The properties of the ceramic slurry of Example 4 and the mechanical properties of the photocured silicon carbide ceramic are shown in Table 1.

[0084] Example 5

[0085] A method for preparing a silicon carbide ceramic slurry and a silicon carbide ceramic material, comprising:

[0086] S1: Prepare 70 parts of 10μm silicon carbide powder, 10 parts of 3.5μm diamond, and 20 parts of phenolic resin (47% residual carbon). Mix the three powders and mill them in a planetary ball mill at 300 rpm for 3 hours. Set the milled mixture aside for later use.

[0087] S2: Select 55 parts of modified polyurethane acrylate and hydroxyethyl methacrylate as resin monomers, and mix them in a mass ratio of 1:1; select bis(1-(2,4-difluorophenyl)-3-pyrrolyl) titanocene as a photoinitiator, the mass of which is 1% of the resin monomer; select K-271 as a dispersant, the mass of which is 1% of the mixed ceramic powder in S1; select DH-4072 as a leveling agent, the mass of which is 1% of the mixed ceramic powder in S1; select K-635 as an anti-settling agent, the mass of which is 1% of the mixed ceramic powder in S1; 100 parts of the mixed ceramic powder obtained in step 1 are mixed with the resin monomer, photoinitiator, dispersant, leveling agent and anti-settling agent, and homogenize them in a non-contact stirrer at a speed of 1200r / min for 3 minutes, and finally prepare a reaction-sintered silicon carbide ceramic slurry for photocuring 3D printing. The obtained slurry has a curing depth of 50μm and a viscosity of 9.2Pa·s (30s -1 ).

[0088] S3: The model in the modeling software is imported into the slicing software, sliced at a thickness of 30 μm, and then the sliced data file is imported into the DLP light-curing printer for printing; the printing parameters of the printer are a wavelength of 405 nm and a curing time of 65 seconds; after printing, a porous silicon carbide ceramic green body is obtained.

[0089] S4: Degreasing the porous silicon carbide ceramic green body obtained in S3 under the protection of high-purity nitrogen (nitrogen gas volume fraction ≥ 99.999%), with a heating rate of 2.5°C / min, a treatment temperature of 600°C, and a holding time of 300min to obtain a silicon carbide ceramic preform.

[0090] S5: The formed preform and a pre-arranged appropriate amount of polycrystalline silicon particles (the mass of which is 60% of the mass of the preform) are used as silicon sources, and high-temperature siliconization reaction sintering is carried out under vacuum conditions at a temperature of 1450° C. and a holding time of 6 hours to obtain a silicon carbide ceramic material.

[0091] The properties of the ceramic slurry of Example 5 and the mechanical properties of the photocured silicon carbide ceramic are shown in Table 1.

[0092] Example 6

[0093] A method for preparing a silicon carbide ceramic slurry and a silicon carbide ceramic material, comprising:

[0094] S1: Prepare 70 parts of 10μm silicon carbide powder, 20 parts of cellulose (40% residual carbon), and 10 parts of phenolic resin (47% residual carbon). Mix the three powders and mill them in a planetary ball mill at 300 rpm for 3 hours. Set the milled mixture aside for later use.

[0095] S2: Select 60 parts of isobornyl acrylate and bisphenol A epoxy acrylate as resin monomers, and mix them in a mass ratio of 2:1; select 819 as a photoinitiator, the mass of which is 1% of the resin monomer; select KOS2400 as a dispersant, the mass of which is 1% of the mixed ceramic powder in S1; select H421 as a leveling agent, the mass of which is 1% of the mixed ceramic powder in S1; select K-635 as an anti-settling agent, the mass of which is 1% of the mixed ceramic powder in S1; 100 parts of the mixed ceramic powder obtained in step 1 are mixed with the resin monomer, photoinitiator, dispersant, leveling agent and anti-settling agent, and homogenized in a non-contact stirrer at a speed of 1200r / min for 3 minutes, and finally prepare a reaction-sintered silicon carbide ceramic slurry for photocuring 3D printing. The obtained slurry has a curing depth of 45μm and a viscosity of 5.5Pa·s (30s -1 ).

[0096] S3: The model in the modeling software is imported into the slicing software, sliced at a thickness of 30 μm, and then the sliced data file is imported into the DLP light-curing printer for printing; the printing parameters of the printer are a wavelength of 405 nm and a curing time of 75 seconds; after printing, a porous silicon carbide ceramic green body is obtained.

[0097] S4: Degreasing the porous silicon carbide ceramic green body obtained in S3 under the protection of high-purity nitrogen (nitrogen gas volume fraction ≥ 99.999%), with a heating rate of 3°C / min, a treatment temperature of 700°C, and a holding time of 60min to obtain a silicon carbide ceramic preform.

[0098] S5: The formed preform and a pre-arranged appropriate amount of polycrystalline silicon particles (the mass of which is 120% of the mass of the preform) are used as silicon sources, and high-temperature siliconization reaction sintering is carried out under vacuum conditions at a temperature of 2000° C. and a holding time of 30 minutes to obtain a silicon carbide ceramic material.

[0099] The properties of the ceramic slurry of Example 6 and the mechanical properties of the photocured silicon carbide ceramic are shown in Table 1.

[0100] Comparative Example 1

[0101] Compared with Example 1, this example selected phenolic resin as the carbon source, and other conditions were the same. The curing depth test was carried out by irradiating ultraviolet light with a wavelength of 405nm for 30s, and the curing depth was measured to be 47μm; at a shear rate of 30s -1 The slurry viscosity is 5.8 Pa·s; the printed green body is pyrolyzed and reactively sintered, and the resulting ceramic has a bending strength of 320 MPa.

[0102] Comparative Example 2

[0103] Compared with Example 1, this example does not add additional carbon source, and other conditions are exactly the same. The curing depth test was carried out by irradiating ultraviolet light with a wavelength of 405nm for 30s, and the curing depth was measured to be 59μm; at a shear rate of 30s -1 When the slurry viscosity is 5.1Pa·s, the printed green body is pyrolyzed, and the deformation and bending of the preform are more serious; the ceramic bending strength after reaction sintering is 234MPa.

[0104] Table 1 Properties of silicon carbide ceramic slurry and mechanical properties of photocured silicon carbide ceramic materials

[0105]

[0106] As shown in Table 1, in Examples 1-6, the viscosity of the slurry can be adjusted by adding different combinations of photosensitizing monomers and photosensitizing diluents and adjusting their ratios. The addition of different carbon sources can also control the flexural strength of the prepared silicon carbide ceramics, reaching up to 420 MPa, significantly higher than the 234 MPa achieved in Comparative Example 2, which does not add any additional carbon source.

[0107] Those skilled in the art will appreciate that the above-described embodiments are specific examples of the present invention, and that in actual applications, various changes in form and detail may be made thereto without departing from the spirit and scope of the present invention. Any person skilled in the art may make changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope defined in the claims.

Claims

1. A silicon carbide ceramic slurry, characterized in that: The slurry comprises the following raw materials in parts by mass: 30 to 80 parts of silicon carbide powder, 20 to 50 parts of a carbon source, 20 to 40 parts of a photosensitive active monomer, 20 to 40 parts of a photosensitive active diluent, and a photoinitiator, a dispersant, a leveling agent, and an anti-settling agent; Among them, the added amount of the photoinitiator is 1% to 5% of the total mass of the photosensitive active monomer and the photosensitive active diluent, the added amount of the dispersant is 0.5% to 3% of the mass of the silicon carbide powder, the added amount of the leveling agent is 0.5% to 2% of the mass of the silicon carbide powder, and the added amount of the anti-settling agent is 0.5% to 2% of the mass of the silicon carbide powder.

2. The silicon carbide ceramic slurry according to claim 1, characterized in that The carbon source includes one or more of phenolic resin, diamond, carbon nanotube, chopped carbon fiber, and cellulose.

3. The silicon carbide ceramic slurry according to claim 1, characterized in that The particle size of the silicon carbide powder ranges from 0.02 to 100 μm; Preferably, the particle size of the silicon carbide powder is in the range of 1 to 50 μm and / or 0.02 to 0.5 μm.

4. The silicon carbide ceramic slurry according to claim 1, characterized in that The photosensitive active monomer includes one or more of ethoxylated trimethylolpropane triacrylate, ethoxylated pentaerythritol tetraacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, epoxy soybean oil acrylate, aliphatic polyurethane acrylate, modified polyurethane acrylate, aromatic polyurethane acrylate, and bisphenol A epoxy acrylate.

5. The silicon carbide ceramic slurry according to claim 1, characterized in that The photosensitive active diluent includes one or more of 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, trimethylolpropane ethoxy triacrylate, ethoxypentaerythritol tetraacrylate, propoxylated neopentyl glycol diacrylate, tripropylene glycol diacrylate, cyclotrimethylolpropane formal acrylate, isobornyl acrylate, hydroxyethyl acrylate, and hydroxyethyl methacrylate.

6. The silicon carbide ceramic slurry according to claim 1, characterized in that The photoinitiator includes one or more of diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide, 2-isopropylthioxanthone, 2,4,6-trimethylbenzoyl-di (p-tolyl) phosphine oxide, and bis (1- (2,4-difluorophenyl) -3-pyrrolyl) titanocene; The dispersant includes one or more of BYK-108, BYK-180, KOS163, KOS110, KOS2400, 17000, and K-271; The leveling agent includes one or more of BYK-323, BYK-333, BYK-354, H421, LS3003, DH-4072, AKN-1181, and AKN-1035; The anti-settling agent includes one or more of KMT-4542, DH-6900, BYK-410, K-635, and AKN-7020.

7. A method for preparing a silicon carbide ceramic slurry according to any one of claims 1 to 6, characterized in that: The preparation method comprises the steps of first mixing silicon carbide powder and a carbon source and ball milling for 1 to 24 hours, then adding a photosensitive active monomer, a photosensitive active diluent, a photoinitiator, a dispersant, a leveling agent, and an anti-settling agent, and then mixing the mixture with a vacuum non-contact stirrer for 1 to 10 minutes to obtain the silicon carbide ceramic slurry; Alternatively, the preparation method comprises mixing silicon carbide powder, a carbon source, a photosensitive active monomer, a photosensitive active diluent, a photoinitiator, a dispersant, a leveling agent, and an anti-settling agent and ball milling them for 1 to 48 hours to obtain the silicon carbide ceramic slurry; The solid phase volume fraction of the obtained silicon carbide ceramic slurry is controlled to be above 40%, and the viscosity is controlled to be 1-10 Pa·s.

8. Use of the silicon carbide ceramic slurry according to any one of claims 1 to 6 in preparing silicon carbide ceramic materials.

9. A method for preparing a silicon carbide ceramic material, characterized in that: The preparation method comprises the following steps: Constructing a geometric model, slicing the geometric model according to a single layer thickness of 10 μm to 100 μm to obtain a data file, and importing the data file into a 3D printer; Preparing a silicon carbide ceramic slurry according to any one of claims 1 to 6; Printing and photocuring the silicon carbide ceramic slurry using a 3D printer combined with the data file, with a single-layer exposure time of 5 to 360 seconds, to obtain a porous silicon carbide ceramic green body; After the porous silicon carbide ceramic green body is fully cleaned and dried, pyrolysis treatment is performed under inert gas protection or vacuum conditions at a heating rate of 1 to 10°C / min, a pyrolysis temperature of 600 to 1500°C, and a holding time of 10 to 300 minutes to obtain a silicon carbide ceramic preform; The silicon carbide ceramic preform is densified by high-temperature silicon infiltration reaction sintering under vacuum conditions at a temperature of 1450-2000° C. for a holding time of 10 minutes to 6 hours to obtain the silicon carbide ceramic material.

10. A silicon carbide ceramic material obtained by the method for preparing a silicon carbide ceramic material according to claim 9.

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