Preparation method of photocuring 3D printing silicon carbide porous ceramic membrane

Abstract

The invention discloses a preparation method of a photocuring 3D printing silicon carbide porous ceramic membrane, which comprises the following steps: preparing silicon carbide slurry by using silicon carbide powder and photosensitive resin as raw materials, obtaining a ceramic membrane green body by using a photocuring 3D printing forming process, and then obtaining the silicon carbide porous ceramic membrane through a glue discharging-sintering process. By regulating and controlling the components of the photosensitive resin and the silicon carbide powder in the slurry, the slurry shows relatively high curing depth and relatively low curing width, and a high-precision ceramic membrane green body is successfully prepared; meanwhile, by changing the solid content of the slurry and the particle size of silicon carbide particles, the pore structure of the silicon carbide porous ceramic membrane is regulated and controlled, and the prepared ceramic membrane is uniform in pore structure. The silicon carbide porous ceramic membrane is prepared through photocuring 3D printing, the problems that silicon carbide slurry is difficult to photocure, low in precision and the like are solved, the preparation process is simple, the forming rate is high, and an effective way is provided for preparing the silicon carbide porous ceramic membrane in a complex shape.

Description

Technical Field

[0001] The invention relates to a method for preparing a photocuring 3D printed silicon carbide porous ceramic membrane, and belongs to the field of membrane material preparation. Background Art

[0002] Silicon carbide is a compound composed of carbon-silicon covalent bonds, and its basic structural units are SiC4 and CSi4 tetrahedrons. It has the advantages of high hardness, low density, good wear resistance, high thermal conductivity, high thermal expansion coefficient, and strong chemical stability. Silicon carbide ceramic membrane has the advantages of high mechanical strength, low thermal expansion coefficient, corrosion resistance and thermal shock resistance, and is considered to be one of the materials with the most development potential in high-temperature ceramic membrane dust removal technology.

[0003] 3D printing ("additive manufacturing") is a manufacturing technology that converts digital models into physical parts by accumulating materials layer by layer. It has significant advantages over "equivalent material manufacturing" and "subtractive manufacturing" technologies in the field of complex structural parts preparation. There are many types of 3D printing technologies, including material extrusion molding 3D printing (DIW, FDM), laser powder bed sintering 3D printing (SLS, SLM), light-curing 3D printing (DLP, LCD, SLA), etc. Among them, light-curing 3D printing technology has the advantages of high molding accuracy, fast speed, diverse materials, and flexible structure. Light-curing 3D printing ceramic molding technology relies on the photopolymerization reaction of slurry to complete the three-dimensional molding of materials. First, the ceramic powder is mixed with photosensitive resin to prepare ceramic slurry, and then the ceramic green body is printed by light-curing. After the debinding-sintering process, the ceramic material is obtained. Saikat Sinha Ray et al. [Ceramics International 46 (2020) 12480-12488] prepared two different alumina ceramic slurries using coarse alumina particles and fine alumina particles as raw materials, and prepared rectangular alumina green bodies by DLP-3D printing, and obtained alumina ceramics after debinding and sintering. Chen et al. [CeramicsInternational 50 (2024) 1732–1741] mixed alumina powder, sintering aid and photosensitive resin to prepare alumina ceramic membrane slurry, and prepared alumina ceramic membrane green bodies by DLP light curing-3D printing technology, and obtained porous alumina ceramic membranes after high-temperature sintering.

[0004] Due to the high UV absorbance and refractive index of non-oxide ceramics, the curing depth of non-oxide ceramic photocuring slurry is low, making it difficult to complete part molding. Shi et al. [Additive Manufacturing 79 (2024) 103942] used alumina coating to reduce the light absorption of silicon carbide powder. The prepared silicon carbide slurry showed good curing depth. After photocuring 3D printing-sintering, a lattice structured silicon carbide ceramic was obtained. Ho et al. [Additive Manufacturing 73 (2023) 103664] used SiO2 / MgSO4 co-coating method to prepare silicon carbide slurry with good curing performance and obtained silicon carbide ceramic gears with higher precision. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a photocurable 3D printed silicon carbide porous ceramic membrane. By regulating high-curability photosensitive resin and silicon carbide particles, the problem of difficulty in curing silicon carbide ceramic slurry is solved. The silicon carbide porous ceramic membrane slurry prepared by the present invention has good curing performance and stability; the silicon carbide porous ceramic membrane prepared by the present invention has a higher porosity and better pore uniformity.

[0006] The technical solution of the present invention is: A method for preparing a photocurable 3D printed silicon carbide ceramic film, the specific steps of which are as follows: A. Preparation of silicon carbide slurry: trimethylolpropane triacrylate (TMPTA) and hexafunctional polyurethane acrylate (6-PUA) are mixed in a certain proportion to form a photosensitive resin; a certain amount of ceramic powder (silicon carbide (SiC) powder, mullite (3Al2O3·2SiO2) powder, zirconium oxide (ZrO2) powder, calcium oxide (CaO) powder) is added to the photosensitive resin; auxiliary additives are added, and the auxiliary additives are BYK-P104S dispersant and BYK-045 defoamer, and the mixture is evenly mixed by ball milling for a period of time; an appropriate amount of 819 photoinitiator is weighed and added to the ball-milled silicon carbide slurry, and the mixture is evenly mixed by mechanical stirring; bubbles in the slurry are removed by rotary degassing and vacuum degassing to obtain a homogeneous silicon carbide slurry.

[0007] B. 3D printing of silicon carbide ceramic membrane green body. A digital model of the silicon carbide ceramic membrane is constructed through 3D modeling software. The model is imported into the 3D printing software. The slice thickness and exposure intensity of the print are set to generate a 3D printing slice file. The prepared silicon carbide slurry is poured into the trough of the 3D printer. The silicon carbide ceramic membrane green body is formed through photocuring 3D printing. After completion, the printed green body is removed from the printing platform, the slurry remaining on the surface of the green body is cleaned with a cleaning agent, and then dried at a certain temperature.

[0008] C. Sintering of silicon carbide ceramic membrane: placing the silicon carbide ceramic membrane green body in a high-temperature sintering furnace, setting the heating rate and holding time of the debinding-sintering process, and cooling with the furnace after sintering to obtain a silicon carbide porous ceramic membrane.

[0009] Preferably, the ceramic powder content in the silicon carbide porous ceramic membrane slurry is 45-65 wt%, the 819 photoinitiator content is 0.5-1.5 wt%; the auxiliary additives contain half of the dispersant and half of the defoamer, with a total content of 1-3 wt%; and the rest is photosensitive resin.

[0010] Preferably, the content of TMPTA in the photosensitive resin is 80-95 wt%, and the content of PUA is 5-20 wt%.

[0011] Preferably, the amount of mullite (3Al2O3·2SiO2) powder added in the ceramic powder is 2-4wt% of the total amount of the ceramic powder, the amount of zirconium oxide (ZrO2) added is 1-2 wt%, the amount of calcium oxide (CaO) added is 1-2 wt%, and the rest is silicon carbide (SiC) powder.

[0012] Preferably, the particle size of the silicon carbide powder is 5 μm, 10 μm, 20 μm, 30 μm, or 50 μm.

[0013] Preferably, the ball milling mixing speed is 350-450 rpm, and the ball milling mixing time is 2-6 h; the mechanical stirring mixing speed is 500-800 rpm, and the mixing time is 30-60 min; and the silicon carbide slurry degassing rotation speed is 1000-2000 rpm.

[0014] Preferably, the slice thickness of the photocuring process is 25-50 μm, and the exposure intensity is 100-300 mJ / cm 2 .

[0015] Preferably, the cleaning agent is 1,6-hexanediol diacrylate (HDDA) and deionized water, and the drying process is drying at 25 °C for 6 h. Preferably, the debinding time of the silicon carbide ceramic membrane green body is 2-6 h, and the heating rate is 0.5-1.5 °C / min.

[0016] Preferably, the sintering temperature of the silicon carbide ceramic film is 1300-1500°C, the sintering time is 2-4 h, and the heating rate is 2-3°C / min.

[0017] The beneficial effects of the present invention are: The present invention uses photosensitive resin and ceramic powder as raw materials, adopts ball milling mixing and degassing process to obtain photocuring 3D printing silicon carbide ceramic membrane slurry, then obtains silicon carbide ceramic membrane green body by photocuring 3D printing, and then obtains silicon carbide ceramic membrane after debinding-sintering. By combining trimethylolpropane triacrylate (TMPTA) and multifunctional polyurethane (PUA) resin, and optimizing the addition amount of silicon carbide powder, the slurry has good curing performance under low ultraviolet light intensity, and the photocuring 3D printing silicon carbide porous ceramic membrane slurry is successfully prepared. At the same time, by changing the solid content of the slurry and the particle size of silicon carbide particles, the pore structure of the silicon carbide porous ceramic membrane is regulated, and the prepared ceramic membrane has a uniform pore structure. The present invention uses photocuring 3D printing to prepare silicon carbide ceramic membranes, which solves the problems of difficulty in photocuring and low precision of silicon carbide slurry. The preparation process is simple and the forming rate is high, which provides an effective way to prepare silicon carbide ceramic membranes with complex shapes. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is an analysis of the photocuring characteristics of the silicon carbide porous ceramic membrane slurry prepared in Example 3 of the present invention.

[0019] Figure 2 The microscopic morphology of the silicon carbide ceramic membrane green body prepared in Example 3 of the present invention.

[0020] Figure 3 This is the microscopic morphology of the sintered silicon carbide ceramic film prepared in Example 3 of the present invention.

[0021] Figure 4 This is the pore size distribution of the sintered silicon carbide ceramic membrane prepared in Example 3 of the present invention.

[0022] Figure 5 The air permeability of the sintered silicon carbide ceramic membrane prepared in Example 3 of the present invention. DETAILED DESCRIPTION Example 1

[0023] Firstly, trimethylolpropane triacrylate (TMPTA) monomer and hexafunctional polyurethane acrylate (6-PUA) monomer were mixed into a photosensitive resin (TMPTA:6-PUA=95 wt%:5 wt%), and then 45 wt% of ceramic powder (SiC(10 μm):3Al2O3·2SiO2:ZrO2:CaO=96:2:1:1) was added to the photosensitive resin, 0.5 wt% of BYK-P104S dispersant and 0.5 wt% of BYK-045 defoamer were added, and the mixture was ball-milled at 300 rpm for 2 h; 0.5 wt% of 819 photoinitiator was added to the ball-milled silicon carbide slurry, and the mixture was mechanically stirred at 500 rpm for 30 min; and the mixture was degassed at 1000 rpm for 20 min to obtain silicon carbide slurry. The digital model of the silicon carbide ceramic membrane was constructed using 3D modeling software and imported into the software associated with the 3D printer. The slice thickness was set to 50 μm and the exposure intensity was set to 100 mJ / m 2 , generate the slice file required for printing, and form it through light-cured ceramic 3D printing. Use HDDA resin and deionized water to clean the residual slurry on the surface of the green body, dry it at 25 °C for 4 hours, heat it to 600 °C at a heating rate of 0.5 °C / min in an air atmosphere, and keep it warm for 2 hours to fully decompose the resin, and then heat it to 1300 °C at a heating rate of 2 °C / min and keep it warm for 2 hours. The average pore size of the prepared silicon carbide porous ceramic membrane is 5.3 μm, the porosity is about 45%, and the gas permeability is 160 m 3 / (m 2 ·h·kPa). Example 2

[0024] Firstly, trimethylolpropane triacrylate (TMPTA) monomer and hexafunctional polyurethane acrylate (6-PUA) monomer were mixed into a photosensitive resin (TMPTA:6-PUA=80 wt%:20 wt%), and then 65 wt% of ceramic powder (SiC(10 μm):3Al2O3·2SiO2:ZrO2:CaO=92:4:2:2) was added to the photosensitive resin, 1.5 wt% of BYK-P104S dispersant and 1.5 wt% of BYK-045 defoamer were added, and the mixture was ball-milled at 500 rpm for 6 h; 2 wt% of 819 photoinitiator was added to the ball-milled silicon carbide slurry, and the mixture was mechanically stirred at 800 rpm for 60 min; and the mixture was degassed at 2000 rpm for 20 min to obtain silicon carbide slurry. The digital model of the silicon carbide ceramic membrane was constructed using 3D modeling software and imported into the software associated with the 3D printer. The slice thickness was set to 25 μm and the exposure intensity was set to 300 mJ / m 2, generate the slice file required for printing, and form it through light-cured ceramic 3D printing. Use HDDA resin and deionized water to clean the residual slurry on the surface of the green body, dry it at 25 °C for 6 h, heat it to 600 °C at a heating rate of 1.5 °C / min in an air atmosphere, and keep it warm for 2 h to fully decompose the resin, and then heat it to 1500 °C at a heating rate of 3.0 °C / min and keep it warm for 2 h. The average pore size of the prepared silicon carbide porous ceramic membrane is 2.2 μm, the porosity is about 40%, and the gas permeability is 15 m 3 / (m 2 ·h·kPa). Example 3

[0025] Firstly, trimethylolpropane triacrylate (TMPTA) monomer and hexafunctional polyurethane acrylate (6-PUA) monomer were mixed into a photosensitive resin (TMPTA:6-PUA=90 wt%:10 wt%), and then 25 wt% of ceramic powder (SiC(10 μm):3Al2O3·2SiO2:ZrO2:CaO=94:3:1.5:1.5) was added to the photosensitive resin, 1.0 wt% of BYK-P104S dispersant and 1.0 wt% of BYK-045 defoamer were added, and the mixture was ball-milled at 400 rpm for 4 h; 1.0 wt% of 819 photoinitiator was added to the ball-milled silicon carbide slurry, and the mixture was mechanically stirred at 600 rpm for 45 min; and the mixture was degassed at 1500 rpm for 20 min to obtain silicon carbide slurry. The digital model of the silicon carbide ceramic membrane was constructed using 3D modeling software and imported into the software associated with the 3D printer. The slice thickness was set to 50 μm and the exposure intensity was set to 200 mJ / m 2 , generate the slice file required for printing, and form it through light-cured ceramic 3D printing. Use HDDA resin and deionized water to clean the residual slurry on the surface of the green body, dry it at 25 °C for 2 h, heat it to 600 °C at a heating rate of 1.0 °C / min in an air atmosphere, and keep it warm for 2 h to fully decompose the resin, and then heat it to 1400 °C at a heating rate of 2.5 °C / min and keep it warm for 2 h. The average pore size of the prepared silicon carbide porous ceramic membrane is 3.5 μm, the porosity is about 43%, and the gas permeability is 60 m 3 / (m 2 ·h·kPa).

[0026] Figure 1 The photocuring characteristics of the silicon carbide porous ceramic membrane slurry prepared in this embodiment are shown in FIG. 1 , and the exposure intensity is 200 mJ / m 2When , the curing depth of the slurry reaches 60 μm, and the curing width is close to 0, indicating that the slurry has good curing performance and can meet the requirements of high-precision photocuring 3D printing. Figure 2 This is the surface and cross-sectional micromorphology of the silicon carbide porous ceramic membrane green body prepared in this embodiment. The silicon carbide particles are evenly distributed in the cured resin, and the resin acts as a binder. After a layer-by-layer 3D printing process, the ceramic membrane green body is obtained. Figure 3 This is the surface and cross-sectional micromorphology of the sintered silicon carbide porous ceramic membrane prepared in this embodiment. During the sintering process, the resin decomposes and acts as a pore-forming agent, leaving a large number of interconnected pores in the silicon carbide ceramic membrane, and the pores are evenly distributed. In addition, the silicon carbide particles are connected by sintering necks, which provides good strength to the silicon carbide membrane. Figure 4 The pore size distribution of the silicon carbide porous ceramic membrane prepared in this example has good concentration, and the main pore size is about 3.5 μm. Figure 5 The gas permeability of the silicon carbide porous ceramic membrane prepared in this example is about 60 m 3 / (m 2 ·h·kPa). Example 4

[0027] Firstly, trimethylolpropane triacrylate (TMPTA) monomer and hexafunctional polyurethane acrylate (6-PUA) monomer were mixed into a photosensitive resin (TMPTA:6-PUA=90 wt%:10 wt%), and then 55 wt% of ceramic powder (SiC(10 μm):3Al2O3·2SiO2:ZrO2:CaO=94:3:1.5:1.5) was added to the photosensitive resin, 1.0 wt% of BYK-P104S dispersant and 1.0 wt% of BYK-045 defoamer were added, and the mixture was ball-milled at 400 rpm for 4 h; 1.0 wt% of 819 photoinitiator was added to the ball-milled silicon carbide slurry, and the mixture was mechanically stirred at 600 rpm for 30 min; and the mixture was degassed at 2000 rpm for 20 min to obtain silicon carbide slurry. The digital model of the silicon carbide ceramic membrane was constructed using 3D modeling software and imported into the software associated with the 3D printer. The slice thickness was set to 25 μm and the exposure intensity was set to 300 mJ / m 2, generate the slice file required for printing, and form it through light-cured ceramic 3D printing. Use HDDA resin and deionized water to clean the residual slurry on the surface of the green body, dry it at 25 °C for 2 h, heat it to 600 °C at a heating rate of 1.0 °C / min in an air atmosphere, and keep it warm for 2 h to fully decompose the resin, and then heat it to 1400 °C at a heating rate of 2.5 °C / min and keep it warm for 4 h. The average pore size of the prepared silicon carbide porous ceramic membrane is 3.2 μm, the porosity is about 42%, and the gas permeability is 55 m 3 / (m 2 ·h·kPa). Example 5

[0028] Firstly, trimethylolpropane triacrylate (TMPTA) monomer and hexafunctional polyurethane acrylate (6-PUA) monomer were mixed into a photosensitive resin (TMPTA:6-PUA=90 wt%:10 wt%), and then 55 wt% of ceramic powder (SiC(5 μm):3Al2O3·2SiO2:ZrO2:CaO=94:3:1.5:1.5) was added to the photosensitive resin, 1.0 wt% of BYK-P104S dispersant and 1.0 wt% of BYK-045 defoamer were added, and the mixture was ball-milled at 450 rpm for 4 h; 1.0 wt% of 819 photoinitiator was added to the ball-milled silicon carbide slurry, and the mixture was mechanically stirred at 600 rpm for 30 min; and the mixture was degassed at 2000 rpm for 20 min to obtain silicon carbide slurry. The digital model of the silicon carbide ceramic membrane was constructed using 3D modeling software and imported into the software associated with the 3D printer. The slice thickness was set to 25 μm and the exposure intensity was set to 300 mJ / m 2 , generate the slice file required for printing, and form it through light-cured ceramic 3D printing. Use HDDA resin and deionized water to clean the residual slurry on the surface of the green body, dry it at 25 °C for 2 h, heat it to 600 °C at a heating rate of 1.0 °C / min in an air atmosphere, and keep it warm for 2 h to fully decompose the resin, and then heat it to 1300 °C at a heating rate of 2.5 °C / min and keep it warm for 2 h. The average pore size of the prepared silicon carbide porous ceramic membrane is 2.5 μm, the porosity is about 42%, and the gas permeability is 14 m 3 / (m 2 ·h·kPa). Example 6

[0029] Firstly, trimethylolpropane triacrylate (TMPTA) monomer and hexafunctional polyurethane acrylate (6-PUA) monomer were mixed into a photosensitive resin (TMPTA:6-PUA=90 wt%:10 wt%), and then 55 wt% of ceramic powder (SiC(50 μm):3Al2O3·2SiO2:ZrO2:CaO=94:3:1.5:1.5) was added to the photosensitive resin, 1.0 wt% of BYK-P104S dispersant and 1.0 wt% of BYK-045 defoamer were added, and the mixture was ball-milled at 450 rpm for 4 h; 1.0 wt% of 819 photoinitiator was added to the ball-milled silicon carbide slurry, and the mixture was mechanically stirred at 600 rpm for 30 min; and the mixture was degassed at 2000 rpm for 20 min to obtain silicon carbide slurry. The digital model of the silicon carbide ceramic membrane was constructed using 3D modeling software and imported into the software associated with the 3D printer. The slice thickness was set to 25 μm and the exposure intensity was set to 300 mJ / m 2 , generate the slice file required for printing, and form it through light-cured ceramic 3D printing. Use HDDA resin and deionized water to clean the residual slurry on the surface of the green body, dry it at 25 °C for 2 h, heat it to 600 °C at a heating rate of 1.0 °C / min in an air atmosphere, and keep it warm for 2 h to fully decompose the resin, and then heat it to 1400 °C at a heating rate of 2.5 °C / min and keep it warm for 2 h. The average pore size of the prepared silicon carbide porous ceramic membrane is 9.4 μm, the porosity is about 41%, and the gas permeability is 131 m 3 / (m 2 ·h·kPa).

Claims

1. A method for preparing a photocurable 3D printed silicon carbide porous ceramic membrane slurry, characterized in that: The preparation method comprises the following steps: A. Preparation of silicon carbide slurry: trimethylolpropane triacrylate (TMPTA) and hexafunctional polyurethane acrylate (6-PUA) are mixed in a certain proportion to form a photosensitive resin; a certain amount of ceramic powder (silicon carbide (SiC) powder, mullite (3Al2O3·2SiO2) powder, zirconium oxide (ZrO2) powder, calcium oxide (CaO) powder) is added to the photosensitive resin; auxiliary additives are added, and the auxiliary additives are BYK-P104S dispersant and BYK-045 defoamer, and the mixture is evenly mixed by ball milling for a period of time; an appropriate amount of 819 photoinitiator is weighed and added to the ball-milled silicon carbide slurry, and the mixture is evenly mixed by mechanical stirring; bubbles in the slurry are removed by rotary degassing and vacuum degassing to obtain a homogeneous silicon carbide slurry; B. 3D printing of silicon carbide ceramic membrane green body: construct a digital model of the silicon carbide ceramic membrane through 3D modeling software, import the model into the 3D printing software, set the slice thickness and exposure intensity of the print, and generate a 3D printing slice file; pour the prepared silicon carbide slurry into the trough of the 3D printer, and form the silicon carbide ceramic membrane green body through photocuring 3D printing; after completion, remove the printed green body from the printing platform, use a cleaning agent to clean the slurry remaining on the surface of the green body, and dry it at a certain temperature; C. Sintering of silicon carbide ceramic membrane: placing the silicon carbide ceramic membrane green body in a high-temperature sintering furnace, setting the heating rate and holding time of the debinding-sintering process, and cooling with the furnace after sintering to obtain a silicon carbide porous ceramic membrane.

2. The method for preparing a photocurable 3D printed silicon carbide porous ceramic membrane slurry according to claim 1, characterized in that: The ceramic powder content in the silicon carbide porous ceramic membrane slurry is 45-65 wt%, the 819 photoinitiator content is 0.5-1.5 wt%, the auxiliary additives include half of the dispersant and half of the defoamer, and the total content is 1-3 wt%, and the rest is photosensitive resin.

3. The method for preparing a photocurable 3D printed silicon carbide porous ceramic membrane slurry according to claim 1, characterized in that: The content of TMPTA is 80~95 wt%, and the content of PUA is 5~20 wt%.

4. The method for preparing a photocurable 3D printed silicon carbide porous ceramic membrane slurry according to claim 1, characterized in that: Ceramic powder is composed of a variety of materials, among which mullite (3Al2O3·2SiO2) powder is added in an amount of 2~4 wt% of the total amount of ceramic powder, zirconium oxide (ZrO2) is added in an amount of 1~2 wt%, calcium oxide (CaO) is added in an amount of 1~2 wt%, and the rest is silicon carbide (SiC) powder.

5. The method for preparing a photocurable 3D printed silicon carbide porous ceramic membrane slurry according to claim 1, characterized in that: The particle sizes of silicon carbide powder are 5 μm, 10 μm, 20 μm, 30 μm and 50 μm.

6. The method for preparing a photocurable 3D printed silicon carbide porous ceramic membrane slurry according to claim 1, characterized in that: The ball milling mixing speed is 350~450 rpm, and the ball milling mixing time is 2~6 h; the mechanical stirring mixing speed is 500~800 rpm, and the mixing time is 30~60 min; the silicon carbide slurry degassing rotation speed is 1000~2000 rpm.

7. The method for preparing a photocurable 3D printed silicon carbide porous ceramic membrane according to claim 1, characterized in that: The slice thickness of the light-curing 3D printing process is 25~50 μm, and the exposure intensity is 100~300 mJ / cm 2 .

8. The method for preparing a photocurable 3D printed silicon carbide porous ceramic membrane according to claim 1, characterized in that: The cleaning agents used in step C are 1,6-hexanediol diacrylate (HDDA) and deionized water, and the drying process is drying at 25 °C for 6 h.

9. The method for preparing a photocurable 3D printed silicon carbide porous ceramic membrane slurry according to claim 1, characterized in that: The heating rate of the debinding process is 0.5~1.5 ℃ / min, and the holding time is 2~6 h; the sintering process temperature is 1300~1500 ℃, the heating rate is 2~3 ℃ / min, and the holding time is 2~4 h.

Images