Photocuring 3D printing TPMS structure silicon carbide ceramic and preparation method thereof

Abstract

The invention belongs to the technical field of silicon carbide 3D printing, and particularly relates to photocuring 3D printing TPMS structure silicon carbide ceramic and a preparation method thereof. Silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin are uniformly mixed to obtain silicon carbide slurry, the mass ratio of the silicon carbide powder with the average particle size of 30-60 microns to the silicon carbide powder with the average particle size of 0.5-5 microns in the silicon carbide powder is 1: (1-3), and the mass ratio of the silicon carbide powder, the magnesium oxide, the cerium oxide and the photosensitive resin is (55-70): (0.5-2): (1-3): (24-45); carrying out DLP photocuring 3D printing on the silicon carbide slurry to obtain a silicon carbide ceramic green body with a TPMS structure; and sequentially carrying out degumming sintering and siliconizing sintering on the silicon carbide ceramic green body with the TPMS structure to obtain the silicon carbide ceramic with the TPMS structure. The silicon carbide ceramic with the TPMS structure prepared by the method disclosed by the invention is high in forming precision, high in solid content and high in yield.

Description

Technical Field

[0001] This invention relates to the field of silicon carbide 3D printing technology, specifically to photopolymerization 3D printing of TPMS structured silicon carbide ceramics and its preparation method. Background Technology

[0002] Silicon carbide ceramics, with their comprehensive qualities such as high specific stiffness, high thermal conductivity, low coefficient of thermal deformation, and good stability, are widely used in high-end manufacturing fields such as aerospace, automotive, and electronic equipment, heat dissipation solutions, and optical systems. However, due to the high hardness and low toughness of silicon carbide materials, coupled with their increasing application in complex structures such as porous, hollow, and thin-walled structures, manufacturing them is challenging. TPMS (Porous Topology Optimized Molecular Structure) is a mathematically defined surface structure characterized by high specific surface area, continuous curvature, and interconnected internal flow channels. The performance of TPMS porous silicon carbide ceramics is closely related to the preparation method; the quality of the preparation method directly determines the quality of the structure. Traditional manufacturing processes, such as slip casting and isostatic pressing, are difficult to achieve such topology-optimized structures.

[0003] Additive manufacturing essentially involves printing objects layer by layer based on digital models to achieve rapid prototyping. Compared to traditional manufacturing processes, it eliminates the need for expensive molds to print precise and complex structures, and near-net-shape manufacturing reduces subsequent processing, significantly improving yield. By combining silicon carbide materials with TPMS structures using additive manufacturing technology, structural components with high specific surface area, lightweight yet high strength, high thermal shock resistance, and excellent thermal insulation properties can be fabricated and widely applied in aerospace, petrochemical, and semiconductor industries. Photopolymerization 3D printing technology utilizes ultraviolet light to induce a polymerization reaction in the slurry, forming a three-dimensional solid. It boasts high molding precision, allowing for accurate control of pore distribution and wall thickness, perfectly replicating the biomimetic channels of TPMS.

[0004] However, due to the high absorbance and high refractive index of silicon carbide under ultraviolet light, less ultraviolet light reaches the polymerizable components in the ceramic slurry, reducing the degree of polymer network formation and thus reducing the thickness of the slurry curing. Furthermore, the dispersion of silicon carbide powder in the ceramic slurry still faces significant challenges, as it is prone to sedimentation, leading to a decrease in solid content and severely affecting the uniformity of the printed blank. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies that combine silicon carbide materials with TPMS structures using additive manufacturing, where silicon carbide leads to decreased curing and stability of the slurry, thus reducing the structural precision and uniformity of the prepared silicon carbide ceramics. This invention proposes a photopolymerization 3D printing method for TPMS-structured silicon carbide ceramics. First, silicon carbide ceramic powder with a specific particle size range is mixed uniformly with magnesium oxide, cerium oxide, and photosensitive resin in a certain proportion to obtain a silicon carbide slurry. The prepared silicon carbide slurry is then used for DLP photopolymerization 3D printing to generate a TPMS-structured silicon carbide ceramic green body. The TPMS-structured silicon carbide ceramic green body is then subjected to debinding sintering and silicon infiltration sintering sequentially to finally obtain the TPMS-structured silicon carbide ceramic. The silicon carbide slurry prepared using the method described in this invention exhibits good curing performance and stability, while the prepared TPMS-structured silicon carbide ceramic has high structural precision and good uniformity. Furthermore, the manufacturing process is simple and the yield is high.

[0006] The first aspect of this invention proposes a method for preparing photopolymerizable 3D printed TPMS-structured silicon carbide ceramics, the method comprising the following steps:

[0007] (1) Silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin are mixed evenly to obtain silicon carbide slurry, wherein the silicon carbide powder contains silicon carbide powder with an average particle size of 30-60 μm and silicon carbide powder with an average particle size of 0.5-5 μm, the mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm is 1:1-3, and the mass ratio of silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin is 55-70:0.5-2:1-3:24-45;

[0008] (2) A digital model of TPMS structured silicon carbide ceramic is constructed using 3D modeling software, sliced ​​and imported into a 3D printer, and the silicon carbide slurry is printed by DLP photopolymerization 3D printing to obtain TPMS structured silicon carbide ceramic green body.

[0009] (3) The TPMS structure silicon carbide ceramic green body is debinded and sintered to obtain a degreased silicon carbide ceramic green body, and the degreased silicon carbide ceramic green body is infiltrated and sintered to obtain a TPMS structure silicon carbide ceramic.

[0010] Preferably, the photosensitive resin is prepared by mixing 1,6-hexanediol diacrylate and trimethylolpropane triacrylate to obtain a mixed solution, and then adding phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and phosphate copolymer to the mixed solution, wherein the volume ratio of 1,6-hexanediol diacrylate to trimethylolpropane triacrylate is 2-10:1, and the ratio of the mixed solution, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and phosphate copolymer is 100mL:1.6-4.8g:3-10mL.

[0011] Preferably, the mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm is 1:1-2.

[0012] Preferably, the mass ratio of silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin is 60-68:0.5-1:1-2.3:30-40.

[0013] Preferably, the volume ratio of 1,6-hexanediol diacrylate to trimethylolpropane triacrylate is 3-4:1; the ratio of the mixed solution, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, and phosphate ester copolymer is 100mL: 2.5-4.5g: 5.2-9.8mL.

[0014] Preferably, the conditions for DLP photopolymerization 3D printing of the silicon carbide slurry include: a light intensity of 28–46 mW / cm². 2 The layer thickness is 0.05–0.07 mm, and the exposure time is 6–10 seconds.

[0015] Preferably, the conditions for debinding and sintering the TPMS-structured silicon carbide ceramic green body include: sintering under an inert atmosphere, debinding time of 9–15 h, heating rate of 0.3–0.9 °C / min, heating to 400–550 °C, and holding time of 2–3 h.

[0016] Preferably, the conditions for silicon infiltration sintering of the degreased silicon carbide ceramic green body include: mixing the degreased silicon carbide ceramic green body with silicon powder, and sintering the resulting mixture under an inert atmosphere for 5-8 hours, with a heating rate of 2-5℃ / min, heating to 1450-1750℃, and holding for 2-3 hours; the mass ratio of the degreased silicon carbide ceramic green body to the silicon powder is 1:1-2, and the particle size of the silicon powder is 0.5-2mm.

[0017] A second aspect of the present invention provides a photopolymerizable 3D printed silicon carbide ceramic with a TPMS structure prepared by the method described above.

[0018] The photopolymerization 3D printing of TPMS structured silicon carbide ceramics and its preparation method described in this invention have the following beneficial effects:

[0019] (1) In this invention, the particle size of silicon carbide powder affects the absorbance and sedimentation rate. By mixing silicon carbide powders of different particle sizes and adding them to photosensitive resin, silicon carbide ceramic slurry is prepared. The slurry has good curing performance under low ultraviolet light intensity. The cured thickness of the silicon carbide slurry is greater than 100 μm after an exposure time of 6 s, and the sedimentation rate of silicon carbide powder is reduced. Specifically, the 24-hour sedimentation height of the silicon carbide slurry is less than 9.5%, and the solid content is greater than 70 wt%. At the same time, by using DLP photopolymerization 3D printing technology and reaction sintering process, silicon carbide ceramics with TPMS structure, high forming accuracy and high solid content are successfully manufactured. The characteristic consistency error of the TPMS structure ceramic green body is less than 0.05%.

[0020] (2) In the preferred case, the proportion of silicon carbide powder with a specific particle size is controlled at a certain level, and the proportion of raw materials for preparing silicon carbide slurry is effectively controlled, so that the curing thickness of the prepared silicon carbide slurry at an exposure time of 6s is greater than 120μm, and the 24h settling height of the silicon carbide slurry is less than 5%. Detailed Implementation

[0021] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0022] The particle size of silicon carbide powder has a significant impact on absorbance and sedimentation rate. Larger silicon carbide powder has lower absorbance, which can increase the curing thickness of the slurry, while smaller silicon carbide powder has a weaker sedimentation effect, which can improve the uniformity of the green body. Therefore, by uniformly mixing large and small particle sizes, the problem of limited curing thickness of ceramic slurry and easy sedimentation of silicon carbide powder can be solved by controlling the particle size of silicon carbide powder.

[0023] The first aspect of this invention proposes a method for preparing photopolymerizable 3D printed TPMS-structured silicon carbide ceramics, the method comprising the following steps:

[0024] (1) Silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin are mixed evenly to obtain silicon carbide slurry, wherein the silicon carbide powder contains silicon carbide powder with an average particle size of 30-60 μm and silicon carbide powder with an average particle size of 0.5-5 μm, the mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm is 1:1-3, and the mass ratio of silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin is 55-70:0.5-2:1-3:24-45;

[0025] (2) A digital model of TPMS structured silicon carbide ceramic is constructed using 3D modeling software, sliced ​​and imported into a 3D printer, and the silicon carbide slurry is printed by DLP photopolymerization 3D printing to obtain TPMS structured silicon carbide ceramic green body.

[0026] (3) The TPMS structure silicon carbide ceramic green body is debinded and sintered to obtain a degreased silicon carbide ceramic green body, and the degreased silicon carbide ceramic green body is siliconized and sintered to obtain a TPMS structure silicon carbide ceramic.

[0027] In the method described in this invention, in a specific embodiment, in step (1), silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin are mixed and stirred and degassed in a gravity mixer by revolution / rotation to obtain a homogeneous silicon carbide slurry. The rotation speed is 800-1300 rpm and the mixing time is 10-60 min.

[0028] In the method described in this invention, in a specific embodiment, the photosensitive resin is prepared as follows: 1,6-hexanediol diacrylate and trimethylolpropane triacrylate are mixed to obtain a mixed solution. A phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and a phosphate ester copolymer are added to the mixed solution. The volume ratio of 1,6-hexanediol diacrylate to trimethylolpropane triacrylate is 2 to 10:1. Specifically, for example, it can be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1. When the volume ratio of 1,6-hexanediol diacrylate to trimethylolpropane triacrylate is less than 2:1, the viscosity of the ceramic slurry is too high, which will affect the flow. The uniformity of the printed layer thickness and the curing speed are important, as excessively fast curing may cause warping or interlayer cracking in the ceramic green body. When the volume ratio of 1,6-hexanediol diacrylate to trimethylolpropane triacrylate is greater than 10:1, the slurry viscosity is too low, which will accelerate particle sedimentation, leading to a decrease in the uniformity of the green body. Moreover, low crosslinking density will reduce the mechanical properties of the green body. The ratio of the mixed solution, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and phosphate ester copolymer is 100mL:1.6-4.8g:3-10mL. Specifically, for example, it can be 100mL:2g:6mL, 100mL:3g:7mL, 100mL:4g:8mL, or 100mL:3g:9mL. Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide is used as a photoinitiator, and phosphate ester copolymer is used as a dispersant.

[0029] In a preferred embodiment of the method of the present invention, the volume ratio of 1,6-hexanediol diacrylate and trimethylolpropane triacrylate is 3-4:1; the ratio of the mixed solution, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and phosphate ester copolymer is 100mL:2.5-4.5g:5.2-9.8mL.

[0030] In the method described in this invention, in a specific embodiment, in step (1), the mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm is 1:1-3. Specifically, for example, it can be 1:1, 1:1.5, 1:2, 1:2.5 or 1:3. When the mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm is less than 1:3, the slurry viscosity increases sharply and the printing curing depth decreases. When the mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm is greater than 1:1, the slurry stability deteriorates, the particle settling rate increases, and the step effect between green layers is significant, resulting in a decrease in printing accuracy.

[0031] In a preferred embodiment of the method described in this invention, the mass ratio of silicon carbide powder with an average particle size of 30 to 60 μm and silicon carbide powder with an average particle size of 0.5 to 5 μm is 1:1 to 2, for example, 1:1, 1:1.5 or 1:2.

[0032] In the method described in this invention, in a specific embodiment, in step (1), the mass ratio of the silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin is 55-70:0.5-2:1-3:24-45. Specifically, for example, it can be 55:1:2:42; 60:0.8:2.2:37; 65:0.7:2:32.3; or 70:0.6:2:27.4. Magnesium oxide is used to reduce the silicon diffusion temperature and increase the density, while cerium oxide can inhibit SiC oxidation and improve high-temperature strength.

[0033] In a preferred embodiment of the method described in this invention, the mass ratio of silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin is 60-68:0.5-1:1-2.3:30-40.

[0034] In the method described in this invention, in a specific embodiment, in step (1), the prepared silicon carbide ceramic slurry has a curing thickness of 100-157 μm, a dynamic viscosity of 1.5-4 Pa·s, and a 24h settling height of 4-10.6% under an exposure time of 6 s.

[0035] In the method described in this invention, the specific operation process of step (2) is as follows: a digital model of the TPMS structure silicon carbide ceramic blank is constructed by three-dimensional modeling software, the model is imported into the 3D printing software, and parameters such as the thickness of the printed slice, exposure intensity, and exposure time are set to generate a 3D printing slice file; the prepared silicon carbide slurry is poured into the material tank of the 3D printer, and the TPMS structure silicon carbide ceramic blank is formed by DLP photopolymerization 3D printing; after completion, the printed blank is removed from the printing platform, and the residual slurry on the surface of the blank is cleaned by using an ultrasonic cleaner and a cleaning agent, and then dried at room temperature. Specifically, the cleaning agent is 95% ethanol, the ultrasonic frequency is 40kHz, and the ultrasonic time is 1 to 10 minutes.

[0036] In the method described in this invention, in a specific embodiment, the conditions for DLP photopolymerization 3D printing of the silicon carbide slurry in step (2) include: a light intensity of 28–46 mW / cm². 2 The layer thickness is 0.05–0.07 mm, and the exposure time is 6–10 seconds.

[0037] In the method described in this invention, in a specific embodiment, the conditions for debinding and sintering the TPMS structured silicon carbide ceramic green body in step (3) include: being carried out under an inert atmosphere, debinding time of 9 to 15 hours, heating rate of 0.3 to 0.9 °C / min, heating to 400 to 550 °C, and holding time of 2 to 3 hours.

[0038] In the method described in this invention, in a specific embodiment, in step (3), the conditions for silicon infiltration sintering of the degreased silicon carbide ceramic blank include: mixing the degreased silicon carbide ceramic blank with silicon powder, and sintering the resulting mixture under an inert atmosphere for a sintering time of 5 to 8 hours, a heating rate of 2 to 5 °C / min, heating to 1450 to 1750 °C, and holding for 2 to 3 hours;

[0039] In this paper, the mass ratio of the degreased ceramic green body to the silicon powder is 1:1 to 2, specifically, for example, 1:1, 1:1.5 or 1:2. When the mass ratio of the degreased silicon carbide ceramic green body to the silicon powder is less than 1:2, molten silicon will overflow and stick to the crucible, and free silicon may be formed, resulting in a decrease in ceramic density. When the mass ratio of the degreased silicon carbide ceramic green body to the silicon powder is greater than 1:1, the amount of silicon may be insufficient to fill the pores, resulting in high porosity, and uneven local reaction may cause internal stress, leading to warping of the green body.

[0040] A second aspect of the present invention provides a photopolymerizable 3D printed silicon carbide ceramic with a TPMS structure prepared by the method described above.

[0041] The following examples further illustrate the photopolymerization 3D printing of TPMS-structured silicon carbide ceramics and its preparation method according to the present invention. The examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0042] Unless otherwise specified, all reagents used in the following examples are commercially available.

[0043] Example 1

[0044] The photosensitive resin is prepared as follows: 1,6-hexanediol diacrylate and trimethylolpropane triacrylate are mixed in a volume ratio of 4:1 to obtain a mixed solution. A phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and phosphate copolymer (product brand name BYK-111) is added to the mixed solution. The ratio of the mixed solution to the phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and phosphate copolymer is 100 mL: 2.98 g: 6.91 mL.

[0045] A method for preparing photopolymerizable 3D printed TPMS structured silicon carbide ceramic, the method comprising the following steps:

[0046] (1) Silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin prepared in Example 1 were mixed and mixed by rotation in a gravity mixer. The mixture was mechanically stirred at 1000 rpm for 20 min to obtain silicon carbide ceramic slurry. The mass ratio of silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin was 67.75:0.75:1.5:30. The mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm was 1:1.5. The solid content of the prepared silicon carbide ceramic slurry was 70 wt%. The curing thickness was 127 μm after an exposure time of 6 s, the dynamic viscosity was 2.63 Pa·s, and the sedimentation height was 6.69% after 24 h.

[0047] (2) A digital model of TPMS-structured silicon carbide ceramic was constructed using 3D modeling software. After slicing, the model was imported into a 3D printer. The slice thickness was set to 60 μm, the exposure time to 8 s, and the exposure intensity to 36 mW / cm². 2 The ceramic green body was formed by DLP photopolymerization 3D printing, and the residual slurry on the surface of the ceramic green body was cleaned by ultrasonication for 5 minutes. It was then dried at room temperature to obtain a TPMS structure silicon carbide ceramic green body. The characteristic consistency error of the TPMS structure ceramic green body was <0.05%.

[0048] (3) The TPMS structured silicon carbide ceramic green body is debinded and sintered under vacuum atmosphere. The temperature is raised to 500℃ at a heating rate of 0.5℃ / min and held for 2h to allow the resin to fully decompose and obtain a debinded silicon carbide ceramic green body. The debinded silicon carbide ceramic green body is mixed with Si particles at a mass ratio of 1:1.5 and then heated to 1550℃ at a heating rate of 3℃ / min and held for 2h to obtain TPMS structured silicon carbide ceramic.

[0049] Example 2

[0050] The photosensitive resin is prepared as follows: 1,6-hexanediol diacrylate and trimethylolpropane triacrylate are mixed in a volume ratio of 4:1 to obtain a mixed solution. Then, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and a phosphate copolymer are added to the mixed solution. The ratio of the mixed solution to the phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and the phosphate copolymer is 100 mL: 2.98 g: 6.91 mL.

[0051] A method for preparing photopolymerizable 3D printed TPMS structured silicon carbide ceramic, the method comprising the following steps:

[0052] (1) Silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin prepared in Example 1 were mixed and mixed by rotation in a gravity mixer. The mixture was mechanically stirred at 1000 rpm for 20 min to obtain silicon carbide ceramic slurry. The mass ratio of silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin was 67.75:0.75:1.5:30. The mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm was 1:2. The solid content of the prepared silicon carbide ceramic slurry was 70 wt%. The cured thickness was 108 μm after an exposure time of 6 s, the dynamic viscosity was 2.98 Pa·s, and the sedimentation height was 5.17% after 24 h.

[0053] (2) A digital model of TPMS-structured silicon carbide ceramic was constructed using 3D modeling software. After slicing, the model was imported into a 3D printer. The slice thickness was set to 50 μm, the exposure time to 7 s, and the exposure intensity to 36 mW / cm². 2 The ceramic green body was formed by DLP photopolymerization 3D printing, and the residual slurry on the surface of the ceramic green body was cleaned by ultrasonication for 5 minutes. It was then dried at room temperature to obtain a TPMS structure silicon carbide ceramic green body. The characteristic consistency error of the TPMS structure ceramic green body was <0.05%.

[0054] (3) The TPMS structured silicon carbide ceramic green body is debinded and sintered under vacuum atmosphere. The temperature is raised to 500℃ at a heating rate of 0.5℃ / min and held for 2h to allow the resin to fully decompose and obtain a debinded silicon carbide ceramic green body. The debinded silicon carbide ceramic green body is mixed with Si particles at a mass ratio of 1:1.5 and then heated to 1550℃ at a heating rate of 3℃ / min and held for 2h to obtain TPMS structured silicon carbide ceramic.

[0055] Example 3

[0056] The photosensitive resin is prepared as follows: 1,6-hexanediol diacrylate and trimethylolpropane triacrylate are mixed in a volume ratio of 4:1 to obtain a mixed solution. Then, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and a phosphate copolymer are added to the mixed solution. The ratio of the mixed solution to the phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and the phosphate copolymer is 100 mL: 2.98 g: 6.91 mL.

[0057] A method for preparing photopolymerizable 3D printed TPMS structured silicon carbide ceramic, the method comprising the following steps:

[0058] (1) Silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin prepared in Example 1 were mixed and mixed by rotation in a gravity mixer. The mixture was mechanically stirred at 1000 rpm for 20 min to obtain silicon carbide ceramic slurry. The mass ratio of silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin was 67.75:0.75:1.5:30. The mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm was 1:1. The solid content of the prepared silicon carbide ceramic slurry was 70 wt%. The curing thickness was 151 μm after an exposure time of 6 s, the dynamic viscosity was 2.06 Pa·s, and the sedimentation height was 9.41% after 24 h.

[0059] (2) A digital model of TPMS-structured silicon carbide ceramic was constructed using 3D modeling software. After slicing, the model was imported into a 3D printer. The slice thickness was set to 70 μm, the exposure time to 8 s, and the exposure intensity to 36 mW / cm². 2 The ceramic green body was formed by DLP photopolymerization 3D printing, and the residual slurry on the surface of the ceramic green body was cleaned by ultrasonication for 5 minutes. It was then dried at room temperature to obtain a TPMS structure silicon carbide ceramic green body. The characteristic consistency error of the TPMS structure ceramic green body was <0.05%.

[0060] (3) The TPMS structured silicon carbide ceramic green body is debinded and sintered under vacuum atmosphere. The temperature is raised to 500℃ at a heating rate of 0.5℃ / min and held for 2h to allow the resin to fully decompose and obtain a debinded silicon carbide ceramic green body. The debinded silicon carbide ceramic green body is mixed with Si particles at a mass ratio of 1:1.5 and then heated to 1550℃ at a heating rate of 3℃ / min and held for 2h to obtain TPMS structured silicon carbide ceramic.

[0061] Example 4

[0062] The photosensitive resin is prepared as follows: 1,6-hexanediol diacrylate and trimethylolpropane triacrylate are mixed in a volume ratio of 3:1 to obtain a mixed solution. Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and phosphate copolymer are added to the mixed solution. The ratio of the mixed solution, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and phosphate copolymer is 100mL:2.99g:6.94mL.

[0063] A method for preparing photopolymerizable 3D printed TPMS structured silicon carbide ceramic, the method comprising the following steps:

[0064] (1) Silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin prepared in Example 1 were mixed and mixed by rotation in a gravity mixer. The mixture was mechanically stirred at 1000 rpm for 20 min to obtain silicon carbide ceramic slurry. The mass ratio of silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin was 67.75:0.75:1.5:30. The mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm was 1:1.5. The solid content of the prepared silicon carbide ceramic slurry was 70 wt%. The curing thickness was 113 μm after an exposure time of 6 s, the dynamic viscosity was 3.05 Pa·s, and the sedimentation height was 4.89% after 24 h.

[0065] (2) A digital model of TPMS-structured silicon carbide ceramic was constructed using 3D modeling software. After slicing, the model was imported into a 3D printer. The slice thickness was set to 60 μm, the exposure time to 7 s, and the exposure intensity to 36 mW / cm². 2 The ceramic green body was formed by DLP photopolymerization 3D printing, and the residual slurry on the surface of the ceramic green body was cleaned by ultrasonication for 5 minutes. It was then dried at room temperature to obtain a TPMS structure silicon carbide ceramic green body. The characteristic consistency error of the TPMS structure ceramic green body was <0.05%.

[0066] (3) The TPMS structured silicon carbide ceramic green body is debinded and sintered under vacuum atmosphere. The temperature is raised to 500℃ at a heating rate of 0.5℃ / min and held for 2h to allow the resin to fully decompose and obtain a debinded silicon carbide ceramic green body. The debinded silicon carbide ceramic green body is mixed with Si particles at a mass ratio of 1:1.5 and then heated to 1550℃ at a heating rate of 3℃ / min and held for 2h to obtain TPMS structured silicon carbide ceramic.

[0067] Example 5

[0068] The photosensitive resin is prepared as follows: 1,6-hexanediol diacrylate and trimethylolpropane triacrylate are mixed in a volume ratio of 4:1 to obtain a mixed solution. Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and phosphate copolymer are added to the mixed solution. The ratio of the mixed solution, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and phosphate copolymer is 100mL:3.05g:9.72mL.

[0069] A method for preparing photopolymerizable 3D printed TPMS structured silicon carbide ceramic, the method comprising the following steps:

[0070] (1) Silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin prepared in Example 1 were mixed and mixed by rotation in a gravity mixer. The mixture was mechanically stirred at 1000 rpm for 20 min to obtain silicon carbide ceramic slurry. The mass ratio of silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin was 67.75:0.75:1.5:30. The mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm was 1:1.5. The solid content of the prepared silicon carbide ceramic slurry was 70 wt%. The curing thickness was 123 μm after an exposure time of 6 s, the dynamic viscosity was 2.69 Pa·s, and the sedimentation height was 4.97% after 24 h.

[0071] (2) A digital model of TPMS-structured silicon carbide ceramic was constructed using 3D modeling software. After slicing, the model was imported into a 3D printer. The slice thickness was set to 60 μm, the exposure time to 8 s, and the exposure intensity to 36 mW / cm². 2 The ceramic green body was formed by DLP photopolymerization 3D printing, and the residual slurry on the surface of the ceramic green body was cleaned by ultrasonication for 5 minutes. It was then dried at room temperature to obtain a TPMS structure silicon carbide ceramic green body. The characteristic consistency error of the TPMS structure ceramic green body was <0.05%.

[0072] (3) The TPMS structured silicon carbide ceramic green body is debinded and sintered under vacuum atmosphere. The temperature is raised to 500℃ at a heating rate of 0.5℃ / min and held for 2h to allow the resin to fully decompose and obtain a debinded silicon carbide ceramic green body. The debinded silicon carbide ceramic green body is mixed with Si particles at a mass ratio of 1:1.5 and then heated to 1550℃ at a heating rate of 3℃ / min and held for 2h to obtain TPMS structured silicon carbide ceramic.

[0073] Comparative Example 1

[0074] The process was carried out in accordance with Example 1, except that the mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm was 1:0.5. The prepared silicon carbide ceramic slurry had a cured thickness of 172 μm, a dynamic viscosity of 1.62 Pa·s, a 24-hour settling height of 12.5%, and a characteristic consistency error of <1% for the prepared TPMS structured ceramic green body.

[0075] Comparative Example 2

[0076] The process was carried out in accordance with Example 1, except that the mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm was 1:4. The prepared silicon carbide ceramic slurry had a cured thickness of 88 μm, a dynamic viscosity of 4.03 Pa·s, a 24-hour settling height of 3.8%, and a characteristic consistency error of <0.05% for the prepared TPMS structured ceramic green body.

[0077] Comparative Example 3

[0078] The process was carried out in accordance with Example 1, except that the mass ratio of silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin was 80:3:4:13. The prepared silicon carbide ceramic slurry had a cured thickness of 52 μm and a dynamic viscosity of 8 Pa·s after an exposure time of 6 s. The sedimentation height after 24 h was 2%. The viscosity was too high, and the printing failed.

[0079] The results from Examples 1-5 and Comparative Examples 1-3 show that silicon carbide ceramic slurry can be prepared by mixing silicon carbide powders of different particle sizes and adding them to photosensitive resin. The slurry has good curing performance under low ultraviolet light intensity, and the sedimentation rate of silicon carbide powder is reduced. Furthermore, the prepared TPMS structured silicon carbide ceramic has high molding precision and high solid content.

[0080] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing photopolymerizable 3D printed TPMS-structured silicon carbide ceramics, characterized in that, The method includes the following steps: (1) Silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin are mixed evenly to obtain silicon carbide slurry, wherein the silicon carbide powder contains silicon carbide powder with an average particle size of 30-60 μm and silicon carbide powder with an average particle size of 0.5-5 μm, the mass ratio of silicon carbide powder with an average particle size of 30-60 μm to silicon carbide powder with an average particle size of 0.5-5 μm is 1:1-3, and the mass ratio of silicon carbide powder, magnesium oxide, cerium oxide and photosensitive resin is 55-70:0.5-2:1-3:24-45; (2) A digital model of TPMS structured silicon carbide ceramic is constructed using 3D modeling software, sliced ​​and imported into a 3D printer, and the silicon carbide slurry is printed by DLP photopolymerization 3D printing to obtain TPMS structured silicon carbide ceramic green body. (3) The TPMS structure silicon carbide ceramic green body is debinded and sintered to obtain a degreased silicon carbide ceramic green body, and the degreased silicon carbide ceramic green body is infiltrated and sintered to obtain a TPMS structure silicon carbide ceramic.

2. The preparation method according to claim 1, characterized in that, The photosensitive resin is prepared by mixing 1,6-hexanediol diacrylate and trimethylolpropane triacrylate to obtain a mixed solution, and then adding phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and phosphate copolymer to the mixed solution. The volume ratio of 1,6-hexanediol diacrylate to trimethylolpropane triacrylate is 2-10:1, and the ratio of the mixed solution, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and phosphate copolymer is 100mL:1.6-4.8g:3-10mL.

3. The preparation method according to claim 1 or 2, characterized in that, The mass ratio of silicon carbide powder with an average particle size of 30–60 μm to silicon carbide powder with an average particle size of 0.5–5 μm is 1:1–2.

4. The preparation method according to claim 3, characterized in that, The mass ratio of silicon carbide powder, magnesium oxide, cerium oxide, and photosensitive resin is 60–68. 0.5～1：1～2.3：30～40。 5. The preparation method according to claim 2, characterized in that, The volume ratio of 1,6-hexanediol diacrylate to trimethylolpropane triacrylate is 3 to 4:1; The ratio of the mixed solution, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and phosphate ester copolymer is 100 mL: 2.5–4.5 g: 5.2–9.8 mL.

6. The preparation method according to claim 1, characterized in that, The conditions for DLP photopolymerization 3D printing of the silicon carbide slurry include: light intensity of 28–46 mW / cm². 2 The layer thickness is 0.05–0.07 mm, and the exposure time is 6–10 seconds.

7. The preparation method according to claim 1, characterized in that, The conditions for debinding and sintering the TPMS structured silicon carbide ceramic green body include: sintering under an inert atmosphere, debinding time of 9–15 h, heating rate of 0.3–0.9 °C / min, heating to 400–550 °C, and holding time of 2–3 h.

8. The preparation method according to claim 1, characterized in that, The conditions for silicon infiltration sintering of degreased silicon carbide ceramic green bodies include: mixing degreased silicon carbide ceramic green bodies with silicon powder, and sintering the resulting mixture under an inert atmosphere for 5-8 hours, with a heating rate of 2-5℃ / min, heating to 1450-1750℃, and holding for 2-3 hours. The mass ratio of the degreased silicon carbide ceramic preform to the silicon powder is 1:1 to 2, and the particle size of the silicon powder is 0.5 to 2 mm.

9. A photopolymerizable 3D printed TPMS structured silicon carbide ceramic prepared by the method of any one of claims 1 to 8.