Silicon carbide ceramic and method of making and use thereof

Abstract

The application provides a silicon carbide ceramic and a preparation method and application thereof, and relates to the technical field of ceramic 3D printing preparation.The preparation method comprises the following steps: mixing silicon carbide powder, carbon black, a dispersing agent and water, grinding, drying and sieving to obtain a powder; mixing the powder with a solidifying agent and then feeding the mixture into a 3D printer, spraying resin at a specified position through a bonding spraying mode, and solidifying the resin by reacting with the solidifying agent to obtain a ceramic green body; mixing high-residual-carbon resin with ethanol to obtain an impregnation solution, and then impregnating and carbonizing the ceramic green body under vacuum to obtain a pretreated ceramic green body; and reacting and sintering the pretreated ceramic green body with silicon particles in a vacuum reaction sintering furnace to obtain a silicon carbide ceramic.The application combines raw material pre-carbonization, vacuum impregnation and carbonization and reaction sintering and silicon infiltration, effectively improves the bulk density and the density of the 3D printed silicon carbide ceramic, and the obtained silicon carbide ceramic can be used for preparing pump flow parts with complex structures.

Description

Technical Field

[0001] This invention relates to the field of ceramic 3D printing preparation technology, specifically to a silicon carbide ceramic, its preparation method, and its application. Background Technology

[0002] Silicon carbide ceramics possess numerous excellent properties, including high wear resistance, high decomposition temperature, and good corrosion resistance, making them ideal for the harsh corrosive and abrasive conditions of specialized industrial pumps. They have been widely used in this field. The wear resistance of silicon carbide ceramics is positively correlated with their bulk density; generally, higher bulk density results in better wear resistance.

[0003] Traditional ceramic forming methods rely on molds to prepare silicon carbide ceramic green bodies. This process is time-consuming, costly, and challenging when producing complex pump flow components such as impellers and volutes. 3D printing technology eliminates the limitations of molds, enabling rapid prototyping and customization. However, 3D-printed ceramic green bodies have significant porosity, resulting in low bulk density after sintering. Therefore, improving the bulk density of 3D-printed silicon carbide ceramic products is crucial for their application in pump flow components.

[0004] To improve the density of 3D-printed silicon carbide ceramic preforms, various combinations of forming and post-processing techniques have emerged in the prior art. One approach involves pre-introducing carbon sources such as carbon black into the printing powder, followed by selective laser sintering (SLS) forming, and then pyrolysis and silicon infiltration reaction sintering. For example, patent application CN106083059A discloses a method for manufacturing complex structure silicon carbide ceramic parts based on laser 3D printing technology. This method involves mixing silicon carbide powder with a carbon-source-containing binder, followed by laser sintering, and then pyrolysis and silicon infiltration reaction sintering to obtain the silicon carbide ceramic part. However, this approach is prone to cracking due to rapid heating and cooling during laser sintering, and the removal of the binder during pyrolysis creates numerous pores within the preform. Furthermore, the amount of silicon infiltration is difficult to control during silicon infiltration, leading to problems such as silicon enrichment causing material brittleness and blockage of silicon infiltration pathways resulting in uneven preform strength. Therefore, the yield rate needs improvement.

[0005] The second approach involves using binder jetting 3D printing to form a silicon carbide ceramic preform, followed by densification treatment using chemical vapor infiltration (CVI) combined with hot isostatic pressing (HIP). For example, patent application CN107098714A discloses a method for manufacturing silicon carbide-based ceramic parts based on 3DP additive manufacturing technology. This method involves obtaining a ceramic preform through binder jetting printing, followed by debinding, and then using a combination of chemical vapor infiltration and hot isostatic pressing to improve density. However, this type of densification process is time-consuming and requires expensive equipment. Furthermore, chemical vapor infiltration has limited penetration depth into complex internal flow channels, making it difficult to achieve uniform densification within the preform. This is unfavorable for the large-scale production of pump flow components with complex internal flow channels, such as impellers and volutes.

[0006] The third approach involves adding a high-carbon-residue resin impregnation and pyrolysis process after the binder-sprayed ceramic blank is obtained and degreased, but before silicon diffusion reaction sintering, to replenish the carbon source inside the blank, thereby improving the density after silicon diffusion reaction sintering. For example, patent application CN115286394A discloses a method for preparing binder-sprayed printed silicon carbide ceramic materials, in which a phenolic resin and alcohol-based impregnation solution is impregnated on a degreased blank, crosslinked and cured, and then pyrolyzed at high temperature to convert it into pyrolyzed carbon, which is then reacted and sintered with silicon. Patent application CN116425548A discloses a binder-sprayed printed silicon carbide ceramic composite material based on particle-graded powder and its preparation method, which uses silicon carbide powder of various particle sizes to print a blank, and similarly impregnates the blank with a phenolic resin and ethanol solution before silicon diffusion reaction sintering. While the above solutions improve the density of silicon carbide ceramics to some extent through resin impregnation and carbonization, none of them have specifically optimized the raw material ratio, printing process and impregnation process parameters for pump flow parts with complex structures such as impellers and volutes that have stringent requirements for wear and corrosion resistance. The resulting ceramic materials still have room for further improvement in bulk density and wear resistance, making it difficult to directly meet the application requirements of special industrial pump flow parts under harsh working conditions.

[0007] In summary, existing 3D printing technologies for silicon carbide ceramics still suffer from problems in the densification process, including crack sensitivity, uneven silicon infiltration, long densification cycles, and high equipment costs. Furthermore, they lack a systematic optimization scheme that considers both powder formulation and impregnation carburization process parameters for pump flow components applications. This results in silicon carbide ceramic products whose bulk density and wear and corrosion resistance fail to meet the stringent requirements of specialized industrial pumps under high-abrasion conditions. Therefore, there is an urgent need for an additive manufacturing method for pump flow components that can retain the advantages of 3D printing technology—freedom from mold limitations and the ability to form complex structures in one step—while significantly improving the density and wear and corrosion resistance of silicon carbide ceramics. Summary of the Invention

[0008] To address the aforementioned issues, this invention provides a silicon carbide ceramic and its preparation method.

[0009] A method for preparing silicon carbide ceramics includes the following steps: S1. Mix silicon carbide powder, carbon black, dispersant and water, grind, dry and sieve to obtain powder; S2. The powder is mixed with a curing agent to obtain a first mixture; the first mixture is fed into a 3D printer, and a first resin is sprayed into the first mixture to carry out a curing reaction to obtain a ceramic green body; S3. Immerse the ceramic green body in the second mixture, soak it at -50 kPa and 30°C for 60 min, dry it at room temperature and then cure it at 80°C to obtain the pretreated ceramic green body; the second mixture is composed of the second resin and ethanol in a mass ratio of 6:4. S4. The pretreated ceramic green body and the pretreated silicon particles are mixed and sintered under vacuum to obtain silicon carbide ceramic; the pretreated silicon particles include the following components in parts by weight: 90 parts silicon particles, 3 parts carbon black, 2 parts boron nitride, 2 parts polyvinylpyrrolidone K90, and 3 parts water.

[0010] In a preferred embodiment, the silicon carbide powder in step S1 is composed of silicon carbide powder with a particle size of 20μm~50μm and silicon carbide powder with a particle size of 60μm~150μm in a mass ratio of (1~3):(7~9).

[0011] In a preferred embodiment, the particle size of the carbon black in step S1 is 5 μm to 10 μm.

[0012] In the preferred embodiment, in step S1, the mass ratio of carbon black to silicon carbide powder is (8~15):100.

[0013] In a preferred embodiment, in step S1, the mass of the dispersant is 0.6% of the mass of the silicon carbide powder.

[0014] In a preferred embodiment, the dispersant in step S1 is at least one of BYK-111 and BYK-066N.

[0015] In a preferred embodiment, in step S2, the mass ratio of the curing agent to the powder is 1:300.

[0016] In a preferred embodiment, the mass ratio of the curing agent to the first resin in step S2 is 1:10.

[0017] In a preferred embodiment, the curing agent in step S2 is a sulfonic acid curing agent.

[0018] In a preferred embodiment, the first resin in step S2 is a 3D furan resin.

[0019] In a preferred embodiment, the second resin in step S3 is at least one of 3D furan resin and phenolic resin.

[0020] In the preferred embodiment, in step S4, the pretreated ceramic green body and the pretreated silicon particles are mixed at a mass ratio of 10:9.

[0021] In the preferred embodiment, the sintering temperature in step S4 is 1600℃~1750℃.

[0022] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: (1) In the technical solution of the present invention, by optimizing the raw material ratio, ceramic green body forming process and impregnation process, the production efficiency of ceramic green body and the wear resistance of the obtained ceramic material are significantly improved. By fully mixing and grinding silicon carbide with carbon black and dispersant, not only is the uniformity and density of powder improved, but also a carbon source is introduced, and finally a high density silicon carbide ceramic product is prepared.

[0023] (2) The present invention uses 3D printing technology to prepare ceramic green bodies, thereby realizing the one-time molding of complex structural parts, getting rid of the limitations of molds and reducing costs.

[0024] (3) The present invention adopts a manufacturing process that combines silicon carbide flow parts with metal shell, so that the final ceramic pump has excellent wear resistance and is suitable for harsh application environments under high wear conditions. Detailed Implementation

[0025] The following description, in conjunction with embodiments, clearly and completely describes the technical solutions of this application, so that those skilled in the art can fully understand this application. Obviously, the described embodiments are merely some preferred embodiments of this application, and not all embodiments. Any equivalent modifications or substitutions made by those skilled in the art to the following embodiments without creative effort are within the protection scope of this application.

[0026] In the following embodiments, the 3D furan resin and curing agent were purchased from Shared Intelligent Equipment Co., Ltd. The phenolic resin was purchased from Leixiang Chemical Industrial Store in Erqi District, Zhengzhou City. The dispersant was purchased from an e-commerce platform.

[0027] A specific embodiment of the present invention provides a method for preparing silicon carbide ceramics, comprising the following steps: S1. Mix silicon carbide powder, carbon black, dispersant, and water, ball mill at 20-45 r / min for 1-2 hours, dry at 100℃, and pass through a 100-500 mesh sieve to obtain powder. The silicon carbide powder is composed of silicon carbide powder with a particle size of 20μm-50μm and silicon carbide powder with a particle size of 60μm-150μm in a mass ratio of (1-3):(7-9); the dispersant is BYK-066N or / and BYK-111, and the amount of dispersant is 0.6% of the mass of silicon carbide powder; the mass ratio of carbon black to silicon carbide powder is (8-15):100, and the particle size of the carbon black is 5μm-10μm; the amount of water is 10%-50% of the total mass of silicon carbide powder, carbon black, dispersant, and water.

[0028] S2. The powder obtained in step S1 is mixed with the curing agent at a mass ratio of 1:300 to obtain a first mixture. A first resin is sprayed into the first mixture using a 3D printer to carry out a curing reaction, thereby obtaining a ceramic green body. The curing agent is a sulfonic acid curing agent; the first resin is a 3D furan resin; and the mass ratio of the curing agent to the first resin is 1:10.

[0029] S3. Immerse the ceramic green body in the second mixture under the following conditions: immersion at -50 kPa and 30°C for 60 min, air-dry at room temperature for 12-24 h, and then cure at 80°C to obtain the pretreated ceramic green body. The second mixture consists of a second resin and ethanol in a 6:4 mass ratio, and the second resin is 3D furan resin and / or phenolic resin.

[0030] S4. The pretreated ceramic green body and pretreated silicon particles are mixed at a mass ratio of 10:9 and placed in a vacuum sintering furnace. The mixture is sintered at 20~200 Pa and 1600℃~1750℃ for 3 hours to obtain silicon carbide ceramic. The pretreated silicon particles comprise the following components by mass: 90 parts silicon particles, 3 parts carbon black, 2 parts boron nitride, 2 parts polyvinylpyrrolidone K90, and 3 parts deionized water.

[0031] Example 1 A method for preparing silicon carbide ceramics includes the following steps: S1. Mix silicon carbide powder, carbon black, dispersant, and water, ball mill at 45 r / min for 2 hours, dry at 100℃, and pass through a 100-mesh sieve to obtain powder. The silicon carbide powder consists of 100 parts of silicon carbide powder with a particle size of 20μm~50μm and 900 parts of silicon carbide powder with a particle size of 60μm~150μm; the dispersant is BYK-066N, and the amount of dispersant is 6 parts; the carbon black has a particle size of 8μm and is used in 100 parts; the amount of water is 240 parts.

[0032] S2. The powder obtained in step S1 is mixed with the curing agent at a mass ratio of 1:300 to obtain a first mixture. A first resin is sprayed into the first mixture using a 3D printer to carry out a curing reaction, thereby obtaining a ceramic green body. The curing agent is a sulfonic acid curing agent; the first resin is a 3D furan resin; and the mass ratio of the curing agent to the first resin is 1:10.

[0033] S3. Immerse the ceramic green body in the second mixture under the following conditions: pressure holding at -50 kPa and 30°C for 60 min, air drying at room temperature for 24 h, and then heating to 80°C for curing to obtain the pretreated ceramic green body. The second mixture consists of a second resin and ethanol in a 6:4 mass ratio, and the second resin is a 3D furan resin.

[0034] S4. The pretreated ceramic green body and pretreated silicon particles are mixed at a mass ratio of 10:9 and placed in a vacuum reactor for sintering at 80 Pa and 1700 °C for 3 hours to obtain silicon carbide ceramic. The pretreated silicon particles consist of the following components in parts by mass: 90 parts silicon particles, 3 parts carbon black, 2 parts boron nitride, 2 parts polyvinylpyrrolidone K90, and 3 parts deionized water.

[0035] Example 2 The preparation method of silicon carbide ceramics in this embodiment is basically the same as that in Example 1, except that the second resin in step S3 is phenolic resin.

[0036] Example 3 A method for preparing silicon carbide ceramics includes the following steps: S1. Mix silicon carbide powder, carbon black, dispersant, and water, ball mill at 30 r / min for 2 hours, dry at 100℃, and pass through a 200-mesh sieve to obtain powder. The silicon carbide powder consists of 300 parts of silicon carbide powder with a particle size of 20 μm to 50 μm and 700 parts of silicon carbide powder with a particle size of 60 μm to 150 μm; the dispersant is BYK-111, with a dispersant dosage of 6 parts; the carbon black has a particle size of 5 μm and is used in 100 parts; the water dosage is 240 parts.

[0037] S2. The powder obtained in step S1 is mixed with the curing agent at a mass ratio of 1:300 to obtain a first mixture. A first resin is sprayed into the first mixture using a 3D printer to carry out a curing reaction, thereby obtaining a ceramic green body. The curing agent is a sulfonic acid curing agent; the first resin is a 3D furan resin; and the mass ratio of the curing agent to the first resin is 1:10.

[0038] S3. Immerse the ceramic green body in the second mixture under the following conditions: pressure holding at -50 kPa and 30°C for 60 min, air drying at room temperature for 24 h, and then heating to 80°C for curing to obtain the pretreated ceramic green body. The second mixture consists of a second resin and ethanol in a 6:4 mass ratio, and the second resin is a 3D furan resin.

[0039] S4. The pretreated ceramic green body and pretreated silicon particles are mixed at a mass ratio of 10:9 and placed in a vacuum reactor for sintering at 80 Pa and 1700 °C for 3 hours to obtain silicon carbide ceramic. The pretreated silicon particles consist of the following components in parts by mass: 90 parts silicon particles, 3 parts carbon black, 2 parts boron nitride, 2 parts polyvinylpyrrolidone K90, and 3 parts deionized water.

[0040] Comparative Example 1 The difference between the preparation method of silicon carbide ceramics in this embodiment and that in Example 1 is that step S3 is omitted, while the remaining steps are the same.

[0041] Comparative Example 2 The difference between the preparation method of silicon carbide ceramics in this embodiment and that in Example 3 is that step S3 is omitted, while the remaining steps are the same.

[0042] Product performance testing According to GB / T 25995-2010 "Test Methods for Density and Apparent Porosity of Fine Ceramics", the apparent porosity and apparent porosity of the silicon carbide ceramics prepared in Examples 1-3 and Comparative Examples 1-2 were tested using an apparent porosity and bulk density meter (model: XQK-01). According to GB / T 6569-2006 "Test Methods for Flexural Strength of Fine Ceramics", the flexural strength of the silicon carbide ceramics was tested using a room temperature compressive strength flexural testing machine (model: CCS-600 / 20p). According to GB / T16534-2009 "Test Methods for Room Temperature Hardness of Fine Ceramics", the hardness of the silicon carbide ceramics was tested using a micro Vickers hardness tester (model: TMVP-1). According to GB / T 18301-2012 "Test Methods for Room Temperature Abrasion Resistance of Refractory Materials", the wear amount of the silicon carbide ceramics was tested using a room temperature abrasion testing machine (model: NMJ-02). The test results are shown in Table 1.

[0043] Table 1. Performance test results of silicon carbide ceramics

[0044] The results in Table 1 show that vacuum impregnation and carburization treatment can improve the bulk density of sintered silicon carbide ceramics, and 3D furan resin has a better effect on improving bulk density than phenolic resin. The gradation ratio of fine silicon carbide powder to coarse silicon carbide powder has a certain influence on the bulk density of silicon carbide; an excessively high proportion of fine silicon carbide is not conducive to improving the bulk density. The higher the bulk density of the ceramic material, the higher the hardness and the lower the wear, that is, the better the wear resistance of the ceramic material. There is no significant difference in the apparent porosity data of the samples in each group. The reason for this is that the pretreated silicon particles added before sintering form silicon vapor during the sintering process, filling the pores of the silicon carbide material, resulting in no significant difference in apparent porosity data. The relationship between the flexural strength and bulk density of the ceramic material is not positively correlated. The reason for this may be that micro-defects generated during sample preparation cause fluctuations in the flexural strength data. Overall, impregnation and carburization can improve the flexural strength of silicon carbide materials.

[0045] The embodiments described above are merely preferred embodiments of this application and are not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by anyone skilled in the art. Any simple equivalent changes and modifications made based on the scope of protection claimed in this application and the content of the specification should be included within the scope of protection of this application.

Claims

1. A method for preparing silicon carbide ceramics, characterized in that, Includes the following steps: S1. Mix silicon carbide powder, carbon black, dispersant and water, grind, dry and sieve to obtain powder; S2. The powder is mixed with a curing agent to obtain a first mixture; the first mixture is fed into a 3D printer, and a first resin is sprayed into the first mixture to carry out a curing reaction to obtain a ceramic green body; S3. Immerse the ceramic green body in the second mixture, soak it at -50 kPa and 30°C for 60 min, dry it at room temperature and then cure it at 80°C to obtain the pretreated ceramic green body; the second mixture is composed of the second resin and ethanol in a mass ratio of 6:

4. S4. The pretreated ceramic green body and the pretreated silicon particles are mixed and sintered under vacuum to obtain silicon carbide ceramic; the pretreated silicon particles include the following components in parts by weight: 90 parts silicon particles, 3 parts carbon black, 2 parts boron nitride, 2 parts polyvinylpyrrolidone K90, and 3 parts water.

2. The preparation method according to claim 1, characterized in that, In step S1, the silicon carbide powder is composed of silicon carbide powder with a particle size of 20μm~50μm and silicon carbide powder with a particle size of 60μm~150μm in a mass ratio of (1~3):(7~9); Or / and, the particle size of the carbon black in step S1 is 5μm~10μm.

3. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of carbon black to silicon carbide powder is (8~15):100; Or / and, in step S1, the mass of the dispersant is 0.6% of the mass of the silicon carbide powder.

4. The preparation method according to claim 1, characterized in that, In step S2, the mass ratio of the curing agent to the powder is 1:300; Or / and, the mass ratio of the curing agent to the first resin in step S2 is 1:

10.

5. The preparation method according to claim 1, characterized in that, In step S1, the dispersant is at least one of BYK-111 and BYK-066N; Or / and, in step S2, the curing agent is a sulfonic acid curing agent.

6. The preparation method according to claim 1, characterized in that, In step S2, the first resin is 3D furan resin; Or / and, in step S3, the second resin is at least one of 3D furan resin and phenolic resin.

7. The preparation method according to claim 1, characterized in that, In step S4, the pretreated ceramic green body and pretreated silicon particles are mixed at a mass ratio of 10:

9.

8. The preparation method according to claim 1, characterized in that, The sintering temperature in step S4 is 1600℃~1750℃.

9. Silicon carbide ceramics prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the silicon carbide ceramic of claim 9 in the preparation of pump flow parts.

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