High-solid and low-viscosity photocured alumina matrix ceramic slurry and preparation method thereof

Abstract

This invention relates to the field of photocurable 3D printing materials, specifically to a high-solids, low-viscosity photocurable alumina-based ceramic slurry and its preparation method. By mass percentage, it comprises the following raw materials: 32-38% photocurable resin, 1.5-2.5% photoinitiator, 2.5-3.5% dispersant, and the balance being ceramic powder particles; wherein the ceramic powder particles include Al2O3 powder and SiC powder, with SiC powder accounting for 0.1-20% of the total mass of the ceramic powder particles, and the ceramic powder particles are graded according to large, medium, and small particle sizes. The ceramic slurry provided by this invention not only possesses good rheological properties and stability, but also improves the solids content, viscosity, and stability of the slurry, resulting in printed parts with high mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of photocurable 3D printing materials, specifically to a high-solids, low-viscosity photocurable alumina matrix ceramic slurry and its preparation method. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] 3D printing, also known as additive manufacturing technology, has unique advantages in manufacturing parts with complex structures and geometries. The additive manufacturing of complex ceramic parts with high mechanical properties has become a hot research topic both domestically and internationally in recent years. The ceramic slurry needs to maintain good rheological properties, stability, and dispersibility while maximizing the solid content to improve the density and mechanical properties of the printed parts.

[0004] However, due to the inherent material properties of alumina, alumina-based ceramic slurries produce parts with low mechanical properties. Therefore, it is necessary to provide a photocurable ceramic slurry to improve the mechanical properties of parts printed from alumina-based ceramic slurries. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a high-solids, low-viscosity photocurable alumina-based ceramic slurry exhibiting excellent rheological properties and stability. The solids content, viscosity, and stability of the slurry are controlled by adjusting the ceramic and polymer components of the slurry system. Furthermore, nano-silicon carbide particles and silicon carbide whiskers are added to toughen the printed parts using nanophase and whisker reinforcement. The present invention also provides a method for preparing the high-solids, low-viscosity photocurable alumina-based ceramic slurry.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] In the first aspect, a high-solids, low-viscosity photocurable alumina-based ceramic slurry is composed of the following raw materials by weight percentage: 32-38% photocurable resin, 1.5-2.5% photoinitiator, 2.5-3.5% dispersant, and the balance being ceramic particle powder;

[0008] The ceramic powder comprises Al2O3 powder and SiC powder, with SiC powder accounting for 0.1-20% of the total mass of the ceramic powder. The ceramic powder is graded by large, medium, and small particle sizes, with large particle size being 1.5-2.5 μm, medium particle size being 0.35-0.45 μm, and small particle size being 0.05-0.15 μm. The dispersant is one or more of the following: silane coupling agent KH-550, silane coupling agent KH-560, rheology modifier BYK-410, and stearic acid SA.

[0009] This invention selects silane coupling agent KH-550, silane coupling agent KH-560, rheology modifier BYK-410 and stearic acid SA as dispersants, which can adsorb long chains of dispersant functional groups on the surface of ceramic particles and powder, forming steric stabilization between particles, thereby effectively improving the stability and dispersion of ceramic slurry, and further reducing the shear viscosity of slurry.

[0010] This invention optimizes the ceramic particle distribution by using a three-level particle size distribution of ceramic particles (wherein, the large and medium-sized ceramic particles are Al2O3 powder, and the small-sized ceramic particles are Al2O3 powder or nano-silicon carbide particles) and adding SiC powder (especially nano-silicon carbide particles and / or silicon carbide whiskers) as an additive phase to the ceramic components, thereby reducing the viscosity of the slurry and improving the mechanical properties of the sintered ceramic.

[0011] On the other hand, a method for preparing the above-mentioned high-solids, low-viscosity photocurable alumina matrix ceramic slurry involves modifying ceramic particle powder with a dispersant, so that the ceramic particle powder adsorbs the long chains of functional groups of the dispersant to obtain modified ceramic particle powder; the modified ceramic particle powder is then mixed evenly with photocurable resin and photoinitiator to obtain the final product.

[0012] This invention first modifies ceramic powder particles using a dispersant. The hydroxyl groups on the surface of the ceramic powder particles physically adsorb onto one end of the dispersant, freeing the hydrophobic long chains in the dispersant and thus increasing the compatibility of the ceramic powder particles with organic matter. Simultaneously, the free hydrophobic long chains on the surface of the modified ceramic powder particles act as steric hindrance, making them more dispersed and stable in photocurable resins, improving the solid-liquid compatibility of the ceramic slurry, and facilitating the preparation of high-performance ceramic slurries.

[0013] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:

[0014] Due to the characteristics of carbide ceramics such as low density, low coefficient of thermal expansion, high thermal conductivity, and high rigidity, this invention incorporates SiC powder as a reinforcing phase into the ceramic slurry. While maintaining the excellent properties of the original alumina-based slurry, high-quality, high-rigidity ceramic parts are produced. This invention improves the solid-liquid compatibility of the slurry system by adjusting the composition and ratio of ceramic and polymer components in the slurry, optimizing the deposition of solid ceramic particles in the slurry, thereby formulating an alumina-based slurry with high solid content, low viscosity, and good stability. Simultaneously, silicon carbide whiskers and nano-silicon carbide particles are introduced as additive phases; through whisker toughening and nano-phase toughening, the mechanical properties of the components subsequently printed from the slurry are improved. Attached Figure Description

[0015] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0016] Figure 1 This is a sedimentation diagram of the slurry with added silicon carbide whiskers in Example 1;

[0017] Figure 2 Shear viscosity diagram of the slurry with added silicon carbide whiskers in Example 1;

[0018] Figure 3 The graph shows the slurry performance of Comparative Example 1 and the addition of different dispersants in Example 2. Figure 3 (a) shows the sedimentation of the slurry. Figure 3 (b) is the slurry shear viscosity diagram;

[0019] Figure 4 Contact angle test diagrams for modified powders with different dispersants added in Example 2 and Comparative Example 1;

[0020] Figure 5 The images shown are scanning electron microscope (SEM) images of the modified powders of Example 2 and Comparative Example 1 with different dispersants. Figure 5 (a) is unmodified powder, (b) is KH560 modified powder, (c) is BYK410 modified powder, and (d) is SA modified powder.

[0021] Figure 6 The shear viscosity diagram is for the slurry with added silicon carbide particles in Example 3. Detailed Implementation

[0022] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] The development and research of ceramic slurry systems based on photopolymerization 3D printing technology is of great significance for broadening the application scope of photopolymerization technology and promoting its development. With the development of photopolymerization additive manufacturing technology, more ceramic material systems and structures can be realized through 3D printing. Existing alumina-based ceramic slurries have good rheological properties and excellent printing performance, but the mechanical properties of the formed parts need improvement. Therefore, this invention provides a high-solids, low-viscosity photopolymerization alumina-based ceramic slurry and its preparation method.

[0024] A typical embodiment of the present invention provides a high-solids, low-viscosity photocurable alumina-based ceramic slurry, which is composed of the following raw materials by weight percentage: 32-38% photocurable resin, 1.5-2.5% photoinitiator, 2.5-3.5% dispersant, and the balance being ceramic particle powder;

[0025] The ceramic powder comprises Al2O3 powder and SiC powder, with SiC powder accounting for 0.1-20% of the total mass of the ceramic powder. The ceramic powder is graded by large, medium, and small particle sizes, with large particle sizes of 1.5-2.5 μm, medium particle sizes of 0.35-0.45 μm, and small particle sizes of 0.05-0.15 μm. The dispersant is one or more of the following: silane coupling agent KH-550, silane coupling agent KH-560, silane coupling agent BYK-410, and stearic acid SA.

[0026] The ceramic powder in the slurry adopts a three-stage particle size distribution (where the large and medium-sized ceramic powders are Al2O3 powder, and the small-sized ceramic powders are either Al2O3 powder or nano-silicon carbide particles). This allows the small-sized ceramic powder to fully fill the voids in the large-sized ceramic particles, ensuring that the sintered alumina matrix ceramic has a high density. Simultaneously, the particle size distribution maximizes the solid content of the slurry, ensuring the mechanical properties of the sintered ceramic. Furthermore, the addition of SiC powder (especially nano-silicon carbide particles and / or silicon carbide whiskers) as an additive phase reduces the viscosity of the slurry and improves the mechanical properties of the sintered ceramic.

[0027] In some embodiments, the large particle size is 1.8–2.2 μm, preferably 1.9–2.1 μm.

[0028] In some embodiments, the particle size is 0.37–0.43 μm, preferably 0.39–0.41 μm.

[0029] In some embodiments, the particle size is 0.07–0.13 μm, preferably 0.09–0.11 μm.

[0030] In some embodiments, the SiC powder is silicon carbide whiskers (SiC w The silicon carbide whiskers have a diameter of 0.1–0.4 μm and a length of 5–15 μm (preferably 8–12 μm). The SiC nanoparticles have a particle size of 0.05–0.1 μm.

[0031] In some embodiments, the photocurable resin is an acrylate monomer HDDA (1,6-hexanediol diacrylate) and TMPTA (trimethylolpropane triacrylate).

[0032] In some embodiments, the photoinitiator is 1,1-dimethoxy-1-phenylacetophenone PI651.

[0033] In some embodiments, the viscosity of the ceramic slurry is 1 to 5 Pa·s.

[0034] Another embodiment of the present invention provides a method for preparing the above-mentioned high-solids, low-viscosity photocurable alumina matrix ceramic slurry. The method involves modifying ceramic particle powder with a dispersant so that the ceramic particle powder adsorbs the long chains of the functional groups of the dispersant to obtain modified ceramic particle powder; the modified ceramic particle powder is then mixed evenly with a photocurable resin and a photoinitiator to obtain the final product.

[0035] This method for preparing ceramic slurry effectively improves the modification effect of ceramic powder, resulting in a ceramic slurry with higher stability and better solid-liquid compatibility, while reducing sedimentation caused by excessive modifier. Furthermore, the obtained high-solids, low-viscosity photocurable alumina-based ceramic slurry exhibits good rheological properties, effectively improving the slurry's solid-liquid compatibility and stability while reducing its viscosity.

[0036] The ceramic particle powder adsorption described in this invention is obtained through physical adsorption; in some embodiments, the modification process is as follows: ceramic particle powder and dispersant are added to a solvent and ultrasonically dispersed to obtain the product.

[0037] In one or more embodiments, the ceramic particle powder is first dried, and then ultrasonically dispersed with a dispersant in a solvent. Specifically, the first drying is vacuum drying. More specifically, the temperature of the first drying is 110–130°C, and the drying time is 10–15 h. More specifically, the heating rate of the first drying is 0.1–3°C / min. Drying under these conditions yields better results.

[0038] In one or more embodiments, a second drying process is performed after ultrasonic dispersion. Specifically, the second drying is vacuum drying. More specifically, the temperature for the second drying is 110–130°C, and the time is 10–15 hours. More specifically, the heating rate for the second drying is 0.1–3°C / min. Drying under these conditions yields better results.

[0039] In one or more embodiments, the solvent is a mixture of ethanol and water. Specifically, the mass ratio of ethanol to water is any, preferably 8.5–9.5:1.5–0.5.

[0040] In one or more embodiments, the ultrasonic dispersion temperature is room temperature. Room temperature as described in this invention refers to the temperature of an indoor environment, typically between 15 and 30°C.

[0041] In some embodiments, a photocurable resin and a photoinitiator are mixed evenly to obtain a liquid phase portion of a ceramic slurry, and then modified ceramic particle powder is added to the liquid phase portion of the ceramic slurry and mixed evenly.

[0042] In one or more embodiments, the mixing temperature of the photocurable resin and the photoinitiator is 30–40°C, and the mixing time is 25–35 min. Under these conditions, the mixing is more uniform.

[0043] In one or more embodiments, the method for mixing the liquid phase of the ceramic slurry with the modified ceramic powder is wet ball milling. Specifically, in wet ball milling, the material-to-ball ratio is 1:4 to 6, the milling time is 7 to 9 hours, and the rotation speed is 150 to 200 r / min. Specifically, in wet ball milling, zirconia grinding balls are used.

[0044] The embodiments of the present invention will be further described below through multiple examples.

[0045] Example 1

[0046] A photocurable ceramic slurry and its preparation method are disclosed. The photocurable ceramic slurry is composed of raw materials with the mass ratios shown in Table 1.

[0047] Table 1. Ceramic Powder Gradation Composition of Example 1 Ceramic Slurry

[0048] Group <![CDATA[2μm Al2O3]]> <![CDATA[0.4μm Al2O3]]> <![CDATA[0.1μm Al2O3]]> <![CDATA[0.1μm SiC w ]]> SW-1 50wt% 33.33wt% 8.33wt% 8.33wt% SW-2 50wt% 33.33wt% 12.5wt% 4.17wt% SW-3 50wt% 33.33wt% 4.17wt% 12.5wt% SW-4 50wt% 25wt% 16.67wt% 8.3wt% SW-5 50wt% 33.33wt% - 16.67wt% SW-6 50wt% 25wt% - 25wt% SW-7 40wt% 30wt% - 30wt%

[0049] The preparation process of photocurable ceramic slurry is as follows:

[0050] Silicon carbide whiskers of corresponding mass fractions were weighed according to different mass ratios to obtain mixed ceramic powders. The mixed ceramic powders were then modified using dispersant KH560 to obtain the ceramic component portion of the ceramic slurry. The photocurable resins HDDA (1,6-hexanediol diacrylate) and TMPTA (trimethylolpropane triacrylate) were mixed with the photoinitiator 2,2-dimethoxy-2-phenylacetophenone (PI651) to obtain the liquid phase portion of the ceramic slurry, which was then mixed with the modified ceramic powder to obtain the ceramic slurry. The modification process included drying the mixed powder, ultrasonic dispersion, and drying the modified powder. The drying conditions were: vacuum drying; heating to 120°C at a rate not exceeding 3°C / min; drying for 12 hours. The solvent for ultrasonic dispersion included an ethanol / water mixture with a mass ratio of 9:1. The ultrasonic dispersion included ultrasonically dispersing the dried ceramic powder, dispersant, and solvent at room temperature for 1 hour. The method for mixing photocurable resin and photoinitiator includes: magnetically stirring the resin and photoinitiator under a 35°C water bath for 30 minutes to obtain the liquid phase of the ceramic slurry. The method for mixing the liquid phase of the ceramic slurry with the modified ceramic powder is wet ball milling. The grinding balls used in the wet ball milling are zirconia grinding balls, the material-to-ball ratio is 1:5, the milling time is 8 hours, and the rotation speed is 180 r / min.

[0051] Example 2

[0052] A photocurable ceramic slurry and its preparation method are disclosed. The photocurable ceramic slurry is composed of the raw materials shown in Table 2.

[0053] Table 2. Composition of photocurable ceramic slurry in Example 2

[0054] Group dispersant prepolymer ceramic powder f1 KH560 HDDA+TMPTA Al2O3+SiC

[0055] The ceramic powder is composed of three particle sizes: coarse (2μm), medium (0.4μm), and fine (0.1μm) silicon carbide nanoparticles, in a mass ratio of 5:3:2. The dispersant accounts for 4% of the total mass, the prepolymer 36%, and the ceramic powder 60%.

[0056] The preparation process of photocurable ceramic slurry is as follows:

[0057] Alumina ceramic powder of the corresponding mass fraction was weighed according to the mass ratio to obtain mixed ceramic powder. The mixed ceramic powder was then modified using dispersant KH560 to obtain the ceramic component portion of the ceramic slurry. The photocurable resin HDDA (1,6-hexanediol diacrylate) and TMPTA (trimethylolpropane triacrylate) were mixed with the photoinitiator 2,2-dimethoxy-2-phenylacetophenone (PI651) to obtain the liquid phase portion of the ceramic slurry, which was then mixed with the modified ceramic powder to obtain the ceramic slurry. The modification process included drying the mixed powder, ultrasonic dispersion, and drying the modified powder. The drying conditions were: vacuum drying; heating to 120°C at a rate of 3°C / min; drying for 12 hours. The solvent for ultrasonic dispersion included an ethanol / water mixture with a mass ratio of 9:1. The ultrasonic dispersion included ultrasonically dispersing the dried ceramic powder, dispersant, and solvent at room temperature for 1 hour. The method for mixing photocurable resin and photoinitiator includes: magnetically stirring the resin and photoinitiator under a 35°C water bath for 30 minutes to obtain the liquid phase of the ceramic slurry. The method for mixing the liquid phase of the ceramic slurry with the modified ceramic powder is wet ball milling. The grinding balls used in the wet ball milling are zirconia grinding balls, the material-to-ball ratio is 1:5, the milling time is 8 hours, and the rotation speed is 180 r / min.

[0058] Example 3

[0059] A photocurable ceramic slurry and its preparation method are disclosed. The photocurable ceramic slurry is composed of raw materials with the mass ratios shown in Table 3.

[0060] Table 3. Ceramic slurry and ceramic powder gradation composition in Example 3

[0061] Group <![CDATA[2μm Al2O3]]> <![CDATA[0.4μm Al2O3]]> 0.05-0.1μm SiC S-1 50wt% 33.33wt% 16.67wt% S-2 50wt% 25wt% 25wt% S-3 60wt% 30wt% 10wt% S-4 50wt% 40wt% 10wt% S-5 60wt% 20wt% 20wt%

[0062] The preparation process of photocurable ceramic slurry is as follows:

[0063] Silicon carbide nanoparticles of corresponding mass fractions were weighed according to different mass ratios to obtain mixed ceramic powders. The mixed ceramic powders were then modified using dispersant KH560 to obtain the ceramic component portion of the ceramic slurry. The photocurable resins HDDA (1,6-hexanediol diacrylate) and TMPTA (trimethylolpropane triacrylate) were mixed with the photoinitiator 2,2-dimethoxy-2-phenylacetophenone (PI651) to obtain the liquid phase portion of the ceramic slurry, which was then mixed with the modified ceramic powder to obtain the ceramic slurry. The modification process included drying the mixed powder, ultrasonic dispersion, and drying the modified powder. The drying conditions were: vacuum drying; heating to 120°C at a rate of 3°C / min; drying for 12 hours. The solvent for ultrasonic dispersion included an ethanol / water mixture with a mass ratio of 9:1. The ultrasonic dispersion included ultrasonically dispersing the dried ceramic powder, dispersant, and solvent at room temperature for 1 hour. The method for mixing photocurable resin and photoinitiator includes: magnetically stirring the resin and photoinitiator under a 35°C water bath for 30 minutes to obtain the liquid phase of the ceramic slurry. The method for mixing the liquid phase of the ceramic slurry with the modified ceramic powder is wet ball milling. The grinding balls used in the wet ball milling are zirconia grinding balls, the material-to-ball ratio is 1:5, the milling time is 8 hours, and the rotation speed is 180 r / min.

[0064] To highlight the beneficial effects of the present invention, the following comparative examples are provided.

[0065] Comparative Example 1

[0066] A photocurable ceramic slurry and its preparation method are disclosed. The photocurable ceramic slurry is composed of the raw materials shown in Table 3.

[0067] Table 4. Composition of Photocurable Ceramic Slurry in Comparative Example 1

[0068] Group dispersant prepolymer ceramic powder f0 - HDDA+TMPTA <![CDATA[Al2O3+SiC]]> f2 SA HDDA+TMPTA <![CDATA[Al2O3+SiC]]> f3 BYK410 HDDA+TMPTA <![CDATA[Al2O3+SiC]]>

[0069] The ceramic powder is composed of three particle sizes: coarse, medium, and fine. The coarse particles are 2μm alumina powder, the medium particles are 0.4μm alumina powder, and the fine particles are 0.1μm silicon carbide nanoparticles, with a mass ratio of 5:3:2. The dispersant accounts for 4% of the mass, the prepolymer accounts for 36%, and the ceramic powder accounts for 60%.

[0070] The preparation process of photocurable ceramic slurry is as follows:

[0071] Weigh alumina ceramic powder according to the specified mass ratio to obtain a mixed ceramic powder. Then, modify the mixed ceramic powder using a dispersant to obtain the ceramic component portion of the ceramic slurry. Mix the photocurable resin HDDA (1,6-hexanediol diacrylate) and TMPTA (trimethylolpropane triacrylate) with the photoinitiator 2,2-dimethoxy-2-phenylacetophenone (PI651) to obtain the liquid phase portion of the ceramic slurry, which is then mixed with the modified ceramic powder to obtain the ceramic slurry. The modification process includes drying the mixed powder, ultrasonic dispersion, and drying the modified powder. The drying conditions are: vacuum drying; heating to 120°C at a rate of 3°C / min; drying for 12 hours. The solvent for ultrasonic dispersion includes an ethanol / water mixture with a mass ratio of 9:1. The ultrasonic dispersion includes ultrasonically dispersing the dried ceramic powder, dispersant, and solvent at room temperature for 1 hour. The method for mixing photocurable resin and photoinitiator includes: magnetically stirring the resin and photoinitiator under a 35°C water bath for 30 minutes to obtain the liquid phase of the ceramic slurry. The method for mixing the liquid phase of the ceramic slurry with the modified ceramic powder is wet ball milling. The grinding balls used in the wet ball milling are zirconia grinding balls, the material-to-ball ratio is 1:5, the milling time is 8 hours, and the rotation speed is 180 r / min.

[0072] Effect test

[0073] To verify the performance of the photocurable ceramic slurry and photocurable ceramics prepared by this invention, this invention also provides an effect test.

[0074] Sedimentation and viscosity tests were performed on the ceramic slurry in Example 1, see reference. Figure 1 and Figure 2 , Figure 1 The settling curve of the ceramic slurry prepared in Example 1 of this invention is shown. Figure 2 This is the viscosity curve of the ceramic slurry obtained in Example 1 of the present invention. Figure 1 It can be seen that with the increase of silicon carbide whisker content, the slurry settling rate increases significantly, but is not lower than 85%. This may be because silicon carbide whiskers are long rods, which easily cause agglomeration and settling of ceramic particles. Figure 2 It can be seen that the viscosity increases with the increase of silicon carbide whisker content, but at a shear rate of 30s... -1 At that time, the viscosity of the slurry was no higher than 3 Pa·s.

[0075] Sedimentation experiments and viscosity tests were conducted on the ceramic slurries in Example 2 and Comparative Example 1, as described in the references. Figure 3 , Figure 3 The graph shows the slurry properties of Example 2 and Comparative Example 1 with different dispersants. Figure 3 (a) It can be seen that for ceramic slurries with high solid content, the dispersant has a significant effect on improving the slurry viscosity, with KH560 showing the best effect in Example 2. Figure 3 (b) It can be seen that all three dispersants play a certain role in the sedimentation of ceramic slurries. The ceramic slurry modified in Example 2 maintains less sedimentation at a lower viscosity, making it the optimal choice for modified alumina-based ceramic slurries.

[0076] To further confirm the modification effect of the dispersant on the ceramic powder, the modified powders from the ceramic slurry of Example 2 and Comparative Example 1 were pressed into tablets, and the contact angle with the trifunctional resin TMPTA was measured. The contact angle was used to characterize the compatibility between the two phases; a larger contact angle indicated less compatibility. The results are as follows: Figure 4 As shown. The better the solid-liquid compatibility of the ceramic slurry, the more stable and dispersed the ceramic powder in the liquid phase, and the less likely it is to form particle agglomeration and sedimentation. From Figure 4 It can be seen that the KH560 modified powder has the smallest contact angle with TMPTA, resulting in excellent stability of the prepared ceramic slurry, with less particle agglomeration and sedimentation. The low sedimentation rate of the SA-modified slurry in Comparative Example 1 is mainly due to the excessive viscosity of the slurry, which makes it difficult for the solid phase to settle, rather than indicating good dispersion. KH560 in Example 2 provides the best improvement in the solid-liquid compatibility of the ceramic slurry.

[0077] The morphology of the modified powders in the ceramic slurries of Example 2 and Comparative Example 1 was characterized using scanning electron microscopy. Please refer to [link to relevant documentation]. Figure 5 , Figure 5 The images shown are scanning electron microscope (SEM) images of the modified powders of Example 2 and Comparative Example 1 with different dispersants. Figure 5 (a) Unmodified powder, (b) KH560 modified powder, (c) BYK410 modified powder, and (d) SA modified powder. As shown in the figure, the unmodified powder in Comparative Example 1 exhibits severe agglomeration, with alumina powders of different particle sizes clustering together to form clumps. The BYK410-modified and SA-modified ceramic powders in Comparative Example 1 are also relatively dispersed, but their surface adsorption effect is not as good as that of KH560. In contrast, the modified powder in Example 2 is more dispersed, with adsorbent modifiers on the particle surface.

[0078] Viscosity tests were performed on the ceramic slurry in Example 3, see reference. Figure 6 , Figure 6 This is the viscosity curve of the ceramic slurry obtained in Example 3 of the present invention. Figure 6 It was found that all five slurries exhibited significant shear thinning, which is beneficial for smoothing during the printing process. With the increase of the content of 0.05-0.1μm small-diameter SiC particles, the slurry viscosity showed an upward trend, but remained relatively stable at a shear rate of 30s. -1 At that time, the viscosity of the slurry was no higher than 3 Pa·s. It exhibited the same excellent rheological properties as the slurry with silicon carbide whiskers added in Example 1.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-solids, low-viscosity photocurable alumina-based ceramic slurry, characterized in that, Based on mass percentage, it consists of the following raw materials: 32-38% UV-curable resin, 1.5-2.5% photoinitiator, 2.5-3.5% dispersant, and the balance is ceramic particle powder; The ceramic powder comprises Al2O3 powder and SiC powder, with SiC powder accounting for 0.1-20% of the total mass of the ceramic powder. The ceramic powder is graded by large, medium, and small particle sizes, with a large particle size of 2 μm, a medium particle size of 0.4 μm, and a small particle size of 0.1 μm. The dispersant is a silane coupling agent KH-560. The SiC powder consists of SiC nanoparticles with a particle size of 0.1 μm. The photoinitiator is 1,1-dimethoxy-1-phenylacetophenone. The settling rate of the high-solids, low-viscosity photocurable alumina matrix ceramic slurry is not less than 85%.

2. The high-solids, low-viscosity photocurable alumina-based ceramic slurry as described in claim 1, characterized in that, The photocurable resin is 1,6-hexanediol diacrylate and trimethylolpropane triacrylate.

3. The high-solids, low-viscosity photocurable alumina-based ceramic slurry as described in claim 1, characterized in that, The viscosity of the ceramic slurry is 1~5 Pa·s.

4. A method for preparing the high-solids, low-viscosity photocurable alumina-based ceramic slurry according to claim 1, characterized in that, The ceramic particle powder is modified by using a dispersant to allow the ceramic particle powder to adsorb the long chains of the functional groups of the dispersant, thereby obtaining modified ceramic particle powder; the modified ceramic particle powder is then mixed evenly with a photocurable resin and a photoinitiator to obtain the final product.

5. The method for preparing the high-solids, low-viscosity photocurable alumina-based ceramic slurry as described in claim 4, characterized in that, The modification process is as follows: ceramic particle powder and dispersant are added to a solvent and ultrasonically dispersed to obtain the desired product.

6. The method for preparing the high-solids, low-viscosity photocurable alumina-based ceramic slurry as described in claim 5, characterized in that, The ceramic particles are first dried, and then added to a solvent with a dispersant for ultrasonic dispersion; the first drying is vacuum drying; the temperature of the first drying is 110~130 ℃, the time is 10~15 h; the heating rate of the first drying is 0.1~3℃ / min. After ultrasonic dispersion, a second drying process is performed; the second drying is vacuum drying; the temperature of the second drying is 110~130 ℃, and the time is 10~15 h; the heating rate of the second drying is 0.1~3 ℃ / min. The solvent is a mixture of ethanol and water; the mass ratio of ethanol to water is 8.5~9.5:1.5~0.

5.

7. The method for preparing the high-solids, low-viscosity photocurable alumina-based ceramic slurry as described in claim 4, characterized in that, The photocurable resin and photoinitiator are mixed evenly to obtain the liquid phase of the ceramic slurry. Then, the modified ceramic particle powder is added to the liquid phase of the ceramic slurry and mixed evenly.

8. The method for preparing the high-solids, low-viscosity photocurable alumina-based ceramic slurry as described in claim 7, characterized in that, The mixing temperature of the photocurable resin and the photoinitiator is 30~40 ℃, and the mixing time is 25~35 min; The method for mixing the liquid phase of the ceramic slurry with the modified ceramic powder is wet ball milling; in wet ball milling, the material-to-ball ratio is 1:4~6, the milling time is 7~9 h, and the rotation speed is 150~200 r / min; in wet ball milling, the milling balls used are zirconia milling balls.

Images