Closed silicon carbide ceramic component and preparation method thereof

Abstract

The invention discloses a closed silicon carbide ceramic component and a preparation method thereof.The preparation method comprises the following steps that S1, a three-dimensional digital model of a target closed structural component is subdivided, and at least two semi-closed printing units with openings are obtained; s2, a 3D printing process based on a powder bed is adopted, and silicon carbide biscuit units of all the semi-closed printing units are prepared; s3, residues in the biscuit units are removed from the openings of the biscuit units, and then degreasing treatment is conducted; s4, the cleaned biscuit units are subjected to alignment bonding on the butt joint faces through bonding slurry, an integral biscuit is formed, and the bonding slurry comprises silicon carbide powder, a carbon source and a silicon source; and S5, carrying out reactive sintering treatment on the integral biscuit to prepare the closed silicon carbide ceramic component. According to the method, a process path of split printing, residue cleaning, alignment bonding and integrated sintering is designed, and the technical bottleneck that a high-performance closed silicon carbide component cannot be prepared through traditional 3D printing is broken through.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials technology, and in particular to a closed silicon carbide ceramic component and its preparation method. Background Technology

[0002] Silicon carbide ceramics, due to their high strength, high hardness, excellent wear resistance, corrosion resistance, and good high-temperature stability, have broad application prospects as key structural components in cutting-edge fields such as aerospace, semiconductor equipment, and nuclear energy. With the technological advancements in these fields, the demand for silicon carbide ceramic components with complex geometries, especially those with internal closed flow channels and cavities, is becoming increasingly urgent. Traditional subtractive manufacturing and isostatic pressing techniques are insufficient for efficiently and cost-effectively manufacturing such complex components.

[0003] In recent years, additive manufacturing (3D printing) technology, especially binder jetting technology based on powder beds, has provided a revolutionary solution for near-net-shape forming of complex ceramic components. This technology, by bonding powder layer by layer, can directly manufacture green blanks with extremely high design freedom, which are then debonded and sintered to obtain the final part, effectively overcoming the limitations of traditional processes in terms of geometric complexity. However, when manufacturing completely enclosed hollow structures, the unbonded powder or support material trapped inside the cavity after printing cannot be effectively removed, becoming a significant bottleneck in the application of this technology.

[0004] To address the aforementioned powder removal challenges, a common approach in existing technologies is to virtually divide the closed structure into two or more open sub-components on a 3D model, print and remove powder from each sub-component separately, and then assemble them together. However, this modular manufacturing strategy shifts the technical difficulty from powder removal to connection. Currently, common methods for connecting modular ceramic blanks include using organic adhesives or inorganic ceramic slurries. Organic adhesives completely decompose during subsequent high-temperature sintering, resulting in porous and weak areas at the joints, severely impairing the overall performance of the component. While co-sintering with ordinary ceramic slurries (mainly composed of matrix ceramic powder and temporary binder) results in high porosity and low strength at the interface due to the lack of an effective densification mechanism during sintering. This becomes a source of crack initiation and propagation, failing to meet the stringent requirements of high-performance components for overall uniformity, especially high connection strength and excellent high-temperature reliability. Summary of the Invention

[0005] The present invention aims to solve the technical problem that existing 3D printing technology cannot remove printing residues in the closed cavity and that the bonding interface performance after split printing is far lower than that of the substrate, making it difficult to manufacture high-performance integrated closed silicon carbide structural parts.

[0006] To address the above problems, the first aspect of this invention provides a method for preparing a closed silicon carbide ceramic component, comprising the following steps: S1. Divide the three-dimensional digital model of the target closed structural component to obtain at least two semi-closed printing units with openings. S2. Using a powder bed-based 3D printing process, silicon carbide preform units for each of the semi-enclosed printing units are prepared respectively. S3. Remove the internal residue from the opening of each green blank unit and then perform degreasing treatment; S4. Use adhesive slurry to align and bond the cleaned green blank units on the mating surface to form an integral green blank. The adhesive slurry contains silicon carbide powder, carbon source and silicon source. S5. The overall green blank is subjected to reaction sintering treatment to allow silicon to penetrate into the green blank matrix and the bonding layer, and react with the carbon source to generate silicon carbide, thereby obtaining a closed silicon carbide ceramic component.

[0007] This invention designs a process path of split printing, residue cleaning, alignment bonding, and integrated sintering, breaking through the technical bottleneck of traditional 3D printing's inability to fabricate high-performance closed silicon carbide components. Specifically, the invention ensures the complete removal of residues within the closed cavity through a split design; it employs a special bonding slurry containing a silicon source and undergoes unified reaction sintering, enabling the bonding interface to be completely integrated with the green substrate in terms of microstructure and performance, thus successfully achieving a synergistic balance between complex geometries and excellent overall performance.

[0008] Furthermore, in step S1, a positioning and docking structure is designed on the split docking surface. This docking structure is selected from at least one of the following: mortise and tenon joint, stepped structure, and labyrinth groove structure. Designing a precision docking structure on the split surface improves the alignment accuracy and bonding strength of the separate raw blank units during bonding. This mechanical interlocking design not only increases the bonding area but also provides stable mechanical support before reaction sintering, preventing misalignment and helping to guide the uniform distribution of the bonding slurry, thus laying the structural foundation for ultimately obtaining a high-strength, defect-free interface.

[0009] Furthermore, in step S2, stereolithography or binder jetting is used for printing, and the internal cavity is filled with a water-soluble or thermally decomposable support material during printing. Using stereolithography or binder jetting 3D printing processes enables the high-precision fabrication of blank units with complex shapes; filling the internal cavity with water-soluble or thermally decomposable support materials stabilizes the internal cavity structure and ensures that these support materials can be completely removed in subsequent steps.

[0010] Furthermore, in step S2, the method for removing internal residues is selected from gas purging, liquid flushing, and vibration. The internal residues removed include support material and printing paste / powder. Effective cleaning methods can be selected for different residues (such as solidified paste, loose powder, and soluble support material) to ensure that the internal cavity of each semi-enclosed unit is thoroughly cleaned, providing an impurity-free blank for subsequent high-temperature reaction sintering.

[0011] Furthermore, in the adhesive slurry, the silicon source is selected from at least one of micron-sized silicon powder, nano-sized silicon powder, organosilicon compounds, and silica sol. Different silicon sources can be selected based on the required reactivity, slurry rheology, and cost to ensure participation in the interfacial integration reaction during subsequent sintering.

[0012] Furthermore, in the adhesive slurry, the molar ratio of carbon to silicon is C:Si = (0.5~2):1. Pre-introducing a silicon source into the adhesive slurry significantly improves the bonding strength. The silicon in the preform preferentially reacts with the carbon in the preform to generate silicon carbide, improving the strength between the bonding surface and the substrate. Precisely controlling the molar ratio of carbon to silicon in the adhesive slurry ensures that the silicon-carbon reaction proceeds fully, maximizing the generation of the silicon carbide bonding phase, while controlling the content of residual silicon or residual carbon at a reasonable level, ensuring that the final performance of the interface region is highly matched with the substrate.

[0013] Furthermore, the particle size of the silicon carbide powder used in the adhesive slurry is smaller than that of the silicon carbide powder used in the green body unit. Using finer-particle-size silicon carbide powder in the adhesive slurry helps improve the slurry's rheological properties, allowing it to better fill the microscopic gaps at the mating surfaces and ensure tight contact. Simultaneously, the finer particles have a higher specific surface area and reactivity, enabling them to react more rapidly and fully with silicon and carbon during subsequent reaction sintering, promoting rapid densification of the adhesive layer and thus achieving a stronger bond with the substrate.

[0014] Furthermore, in step S4, the alignment and bonding specifically includes: aligning the mating surfaces of each green blank unit with the assistance of a positioning fixture, uniformly applying the bonding slurry to the mating surfaces, applying pressure to ensure the green blank units are tightly bonded, and then curing and shaping. This process ensures the repeatability and reliability of the bonding process; the applied pressure ensures the minimization of interface gaps and the uniform distribution of the slurry; and the curing and shaping ensures the bonded body has sufficient strength before entering high-temperature sintering, facilitating handling and furnace loading, and reducing the risk of breakage during production.

[0015] Further, step S5 specifically includes: placing the entire green blank in a high-temperature sintering furnace and adding an appropriate amount of silicon source, heating it to 400~800°C under vacuum and holding it for 0.5~2 hours; then heating it to 1400~1650°C and holding it for 1~3 hours to carry out silicon melting and reaction. By employing a sintering process, organic matter is thoroughly removed and a uniform carbon skeleton is formed at a low temperature stage; then, the reaction with silicon at a high temperature stage ensures that the green blank matrix and the adhesive layer can simultaneously and uniformly complete the densification process, ultimately obtaining an integrated component with a uniform microstructure and consistent mechanical properties.

[0016] A second aspect of this invention provides a closed silicon carbide ceramic component, which is prepared by the above-described method. This closed silicon carbide ceramic component has a complex geometry (especially a closed internal cavity), and its overall structural performance is uniform, without the weak interfaces caused by traditional bonding. This component exhibits excellent structural integrity and reliability under harsh conditions such as high temperature, thermal cycling, and load-bearing, making it particularly suitable for high-end fields such as aerospace and semiconductor equipment.

[0017] In summary, compared with the prior art, the present invention has the following beneficial effects: (1) Solving the problem of integrated molding of closed silicon carbide ceramic components: This invention pioneered the technical route of "segmentation printing - cavity cleaning - reaction bonding - integrated sintering". By intelligently segmenting the closed structure into semi-closed units that can be cleaned in three-dimensional space, it solves the industry bottleneck of traditional 3D printing where the performance of components is reduced due to the inability to remove internal cavity residues. Then, relying on the synchronous reaction sintering of the special bonding slurry containing silicon source with the whole blank, the molten silicon penetrates into the bonding layer and the pores of the blank, and silicon carbide is generated in situ to achieve interface metallurgical bonding. Finally, while ensuring the absolute cleanliness of the internal cavity, it realizes the near-net-shape forming and performance integration of closed complex components.

[0018] (2) Achieve a significant improvement in the performance of the bonding interface: This invention transforms the bonding layer from a physical filler into an active reaction system. During the reaction sintering process, the silicon source and silicon carbide source in the bonding layer react synchronously with the matrix to generate a new silicon carbide phase. This new phase forms a direct intercrystalline bond with the silicon carbide particles in the matrix and constructs an interpenetrating network with continuous transition of composition and structure in the interface region. By precisely controlling the carbon / silicon molar ratio in the bonding slurry, the final phase composition of the interface region is highly consistent with the matrix, thereby achieving the same mechanical strength and thermophysical properties as the matrix, completely eliminating the problem of weak performance of traditional bonding interfaces.

[0019] (3) It gives the component excellent thermodynamic stability and service reliability: Since the entire component (including the joint) is made of homogeneous reaction sintered silicon carbide material, the inherent thermal mismatch problem of heterogeneous material connection is completely avoided. The perfect match between the interface and the matrix in terms of thermal expansion coefficient makes it possible for the component to not generate local thermal stress concentration at the joint when subjected to drastic temperature changes or steady-state high temperature loads. This results in excellent thermal shock resistance and thermal fatigue resistance, and extremely high service reliability and lifespan under extreme conditions such as high temperature, thermal cycling and high load.

[0020] (4) Combining complex molding capabilities and process adaptability: Based on fully leveraging the advantages of 3D printing technologies such as stereolithography / binder jetting in manufacturing complex internal channels and topology optimization structures, the splitting strategy, adhesive slurry formulation, and reaction sintering process involved in this invention are highly compatible with existing mature ceramic preparation systems, providing customized solutions for high-performance silicon carbide ceramics for high-end fields such as lightweight components for aerospace and high-cleanliness chambers for semiconductor equipment. Attached Figure Description

[0021] Figure 1 This is a flowchart of a method for preparing a closed silicon carbide ceramic component according to a specific embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the microstructure of the bonding interface of the components in a specific embodiment of the present invention.

[0023] Figure 3 This is a physical image of the nozzle component in Embodiment 1 of the present invention. Detailed Implementation

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0027] The present invention provides a closed silicon carbide ceramic component based on 3D printing and reaction sintering and its preparation method. Through the whole process of split printing, residue cleaning, alignment bonding and integrated sintering, the technical problem of traditional methods being unable to manufacture closed silicon carbide components with clean interior and high interface performance is solved, and the preparation of components with complex structure and overall performance is finally realized.

[0028] Combination Figure 1 As shown, the fabrication method of the closed silicon carbide ceramic component specifically includes the following steps: S1, structural design and partitioning; S2, semi-closed unit printing; S3, cleaning and degreasing; S4, precision bonding of green body units; S5, integrated reaction sintering. The specific implementation process of each step is as follows: S1. Structural Design and Partitioning This step aims to transform an indivisible closed structure into a manufacturable semi-closed unit and lay the foundation for subsequent high-precision bonding.

[0029] Import the 3D digital model of the target enclosed structural component using computer-aided design software to identify its completely enclosed internal cavities or flow channels. Based on the component's geometry, stress conditions, and subsequent process requirements (such as facilitating degreasing and silicon infiltration), virtual partitioning is performed in non-critical load-bearing areas or areas with regular shapes, dividing the overall model into two or more semi-enclosed printing units. Crucially, each partitioned printing unit must retain at least one opening for subsequent removal of internal residues. Finally, a unit-by-unit printing file suitable for the selected 3D printing process is generated.

[0030] Preferably, the split surface needs to be designed with a precision mating structure, such as interlocking tenons and mortises, steps or labyrinth grooves, to improve the mating accuracy and mechanical interlocking effect.

[0031] S2, Semi-closed unit printing The goal of this step is to transform the digital model into a physical entity and use powder bed 3D printing technology to accurately form each semi-enclosed preform unit.

[0032] In a specific embodiment, the materials are prepared according to the selected printing process: If stereolithography is used, silicon carbide micropowder, carbon source (such as phenolic resin, carbon black), photosensitive resin, etc. are uniformly mixed in a ball mill to prepare a ceramic slurry. If binder jetting technology is used, silicon carbide micropowder, carbon source, and binder are thoroughly mixed in a dry mixer to prepare a composite powder.

[0033] Printing process: Using appropriate 3D printing equipment, each semi-enclosed silicon carbide preform unit is printed layer by layer according to the unit printing file generated by S1. When printing to form the internal cavity structure, water-soluble support material (such as polyvinyl alcohol PVA) or thermally decomposable support material (such as polylactic acid PLA) is used for filling to maintain structural stability during the printing process.

[0034] S3, Cleaning and Degreasing This step aims to purify the interior of the green body unit and remove most of the organic matter, providing a clean, porous green body for subsequent high-temperature processing.

[0035] Cleaning: After printing, thoroughly remove all internal residues using physical methods through the pre-drilled openings on each semi-enclosed unit. The cleaning method can be selected based on the type of residue: for uncured paste or loose powder, use ultrasonically assisted organic solvents (such as ethanol or acetone) for rinsing, or compressed air / airflow for purging; for water-soluble support materials, use warm water immersion to dissolve and rinse; for thermally decomposable support materials, remove them simultaneously during the initial degreasing stage. This step must ensure that all residues inside the cavities are completely removed.

[0036] Degreasing treatment: The cleaned green blank unit is placed in an atmosphere sintering furnace and heated to 400~600℃ under air or inert atmosphere protection, and held for 1~3 hours. This process aims to fully decompose, volatilize and remove organic components such as photosensitive resin and binder in the green blank, forming a pure porous silicon carbide / carbon green blank unit with a certain strength.

[0037] S4, Precision bonding of raw blank units This step is the core of achieving interface integration, which uses a specially formulated reactive adhesive slurry to connect the separate raw blanks into a whole blank.

[0038] Preparation of the bonding slurry: A bonding slurry rich in reactants and matching the composition of the green body is prepared. A typical formulation is: 50-70 wt.% fine-grained or nano-sized silicon carbide powder, 20-40 wt.% silicon source, and 5-15 wt.% carbon source (such as carbon black or liquid phenolic resin). The powder is mixed with solvents such as ethanol and acetone and ground into a paste in a three-dimensional mixer, controlling its viscosity within the range of 5000-20000 mPa·s to facilitate coating and filling. The molar ratio of carbon to silicon (C:Si) in the slurry needs to be precisely controlled, typically between 0.5:1 and 2:1, to ensure complete reaction and control residual silicon content. Preferably, the particle size of the silicon carbide powder used in the bonding slurry is smaller than that used in the green body unit, allowing the bonding slurry to better fill the microscopic gaps at the mating surfaces and achieve rapid densification during subsequent reaction sintering.

[0039] Alignment and Bonding: Fix each cleaned and degreased green blank unit to the positioning fixture, ensuring accurate alignment and fit of its designed parting surfaces. Apply the prepared bonding slurry evenly to the mating interface, utilizing vacuum assistance or capillary action to fully fill the mating gaps and micropores on the green blank surface. Apply a slight pressure of 0.1~0.5MPa to ensure tight contact, then cure and set at 80~120℃ for 0.5~1 hour to form a monolithic blank with sufficient handling strength.

[0040] S5, Integrated Reaction Sintering This step is crucial for final densification and achieving integrated performance. Through a unified reaction sintering process, the bonding interface and the green body are completely integrated in terms of microstructure.

[0041] The bonded monolithic blank and silicon source are placed in a high-vacuum, high-temperature sintering furnace. In a specific embodiment, the sintering process is divided into the following two stages: Low-temperature carbonization stage: Slowly raise the temperature to 400-800°C at a rate of 1-3°C / min and hold for 0.5-2 hours. The purpose of this stage is to further decompose and carbonize the small amount of residual organic matter in the adhesive slurry and the raw blank, forming a uniform and continuous carbon network.

[0042] High-temperature reaction sintering stage: Continue heating at a rate of 3~5℃ / min to the target sintering temperature of 1400~1650°C, and hold at this temperature for 1~3 hours. During this stage, silicon volatilizes to form silicon vapor, providing a silicon source for the green body. The gaseous silicon permeates into the porous green body and bonding layer through capillary action, reacting with the carbon within to generate a new silicon carbide phase in situ. This process not only fills the pores inside the green body, achieving densification, but more importantly, the newly grown silicon carbide phase at the bonding interface forms a direct intergranular bond with the matrix silicon carbide particles, thus firmly bonding the interface and matrix together at the atomic scale. Its microstructure is as follows: Figure 2 As shown. After sintering, the furnace is cooled to room temperature to obtain a high-performance closed silicon carbide ceramic component.

[0043] The above-described implementation method, through precise control of process parameters throughout the entire process, produces closed silicon carbide ceramic components that are clean inside, structurally intact, and thermodynamically stable. This method is particularly suitable for manufacturing closed load-bearing structures that require lightweight design in the aerospace field, as well as components such as heating plates, cavities, and manifolds with complex internal flow channels in semiconductor equipment.

[0044] The technical effects of the present invention will be described below with reference to specific embodiments. Unless otherwise specified, the raw materials used in the embodiments of this application were all purchased through commercial channels.

[0045] In a specific embodiment, performance testing is performed on the component, and the testing items include: Sealing performance testing: The airtightness of the internal sealed cavity of the component is tested using helium mass spectrometry leak detection method.

[0046] Interface mechanical property testing: The bonding strength of the adhesive interface is characterized by the interface shear strength test.

[0047] Thermal cycling reliability testing: The component is subjected to a specified number of thermal cycles, and then the bonding interface area is inspected for damage such as cracks and separation to evaluate its thermal shock resistance and long-term thermal stability.

[0048] Interface microstructure analysis: The microstructure of the bonding interface is observed using a scanning electron microscope to check for defects such as gaps and holes.

[0049] Interface element analysis: Elemental surface distribution analysis is performed using an energy dispersive spectrometer.

[0050] Example 1 The steps for fabricating a semiconductor reaction chamber nozzle with an internal spiral cooling channel are as follows: (1) Digital model and partitioning design: A 3D solid model of the target nozzle was constructed using 3D modeling software. The nozzle contains a closed spiral cooling channel. Based on the model's geometric features and subsequent process requirements, the nozzle model was virtually divided into two completely symmetrical semi-cylindrical shell units along its axial symmetry plane. The inner wall of each shell unit contains a half-spiral channel groove. Interlocking precision stepped structures were designed at the edges of the split surface to facilitate alignment. A slice file suitable for stereolithography printing was generated.

[0051] (2) Ceramic slurry preparation and semi-closed unit printing: Stereopolymerization technology was used for printing. The ceramic slurry was prepared by uniformly mixing 85 wt.% silicon carbide micropowder (D50=1.0μm), 10 wt.% phenolic resin, 2 wt.% carbon powder, and 3 wt.% photosensitive resin to form a homogeneous slurry. Using this slurry, two semi-enclosed nozzle preform units were printed according to the design document in step (1). During printing, water-soluble polyvinyl alcohol (PVA) was used as the support material to fill the internal spiral flow channel area.

[0052] (3) Cleaning and degreasing treatment: After printing, the uncured slurry and PVA support material in the flow channels are thoroughly removed by ultrasonic cleaning with ethanol through the openings at both ends of the preform unit. Then, the cleaned preform unit is placed in a muffle furnace and heated to 550°C at a programmed rate of 1°C / min in air atmosphere, and held at that temperature for 2 hours to complete the degreasing process, obtaining a pure porous silicon carbide / carbon preform unit.

[0053] (4) Preparation of adhesive slurry and precision bonding of raw blank: Prepare the reactive adhesive slurry: The slurry comprises 50 wt.% nano-silicon carbide powder (D50=200nm), 30 wt.% micron-sized silicon powder, 10 wt.% carbon black, and 10 wt.% phenolic resin ethanol solution. Ball mill the above components to form a homogeneous slurry, controlling the viscosity to approximately 10000 mPa·s. With the aid of a precision alignment fixture, align two cleaned and degreased semi-cylindrical blank units along the designed stepped parting surfaces. Apply the adhesive slurry evenly, press and fix them together, and cure at 50°C.

[0054] (5) Integrated reaction sintering: The bonded monolithic preform and silicon source were placed in a high-vacuum sintering furnace, and the temperature was increased to 600℃ at a rate of 1℃ / min, held for 2 hours to fully decompose residual organic matter; then the temperature was increased to 1550℃ at a rate of 5℃ / min, and sintered in a vacuum environment (≤10 -2 (Pa) Hold at this temperature for 1 hour to allow for the infiltration and reaction sintering of gaseous silicon. Cool to room temperature with the furnace to obtain a dense, integrated silicon carbide nozzle component. The product appearance is as follows: Figure 3 As shown.

[0055] (6) Performance testing: The fabricated nozzle component was tested. Helium mass spectrometry leak detection showed that the internal spiral cooling channel was completely sealed, with a leak rate of less than 1×10⁻⁶. -9 Pa·m 3 Three-point bending tests showed that the component's bending strength reached 320 MPa, and fracture occurred in the matrix rather than the bonding interface, proving that the interfacial bond strength was higher than that of the raw blank matrix. After 100 thermal cycles from room temperature to 1200℃, no cracks or separation were observed at the bonding interface. Scanning electron microscopy revealed no visible gaps at the bonding interface. Elemental distribution showed that Si and C elements were continuous and uniform at the interface, achieving integrated microstructure.

[0056] Example 2 The steps for fabricating an electrostatic chuck base for semiconductors with internal multi-channel cooling channels are as follows: (1) Digital model and partitioning design: A 3D solid model of the target electrostatic chuck base was constructed using 3D modeling software. The base contains isolated, multi-path, parallel tree-like branching cooling channels. For ease of manufacturing, the model was divided into upper and lower cover-type units along the symmetry plane of the channel tree, with half of the channel groove machined into the inner surface of each unit. A labyrinth groove and locating pin hole composite docking structure was designed on the split surface. A slice file suitable for adhesive jet printing was generated.

[0057] (2) Composite powder preparation and semi-closed unit printing: The printing process employed binder jetting technology. Ceramic slurry preparation: 90 wt.% silicon carbide powder (D50=25μm) and 10 wt.% phenolic resin powder were dry-mixed uniformly in a mixer. Using this composite powder, two cover plate blank units were printed according to the design document from step (1). During printing, the complex internal flow channel areas were filled with thermally decomposable polymethyl methacrylate microspheres as a support material.

[0058] (3) Cleaning and degreasing treatment: After printing, most of the loose powder is initially removed by high-pressure airflow and vibration. Then, the flow channel is pressurized and rinsed with organic solvent through the flow channel opening to thoroughly remove residual powder and PMMA support material fragments. The cleaned preform unit is then placed in a tube furnace and heated to 600°C at a rate of 2°C / min under flowing nitrogen protection, and held for 3 hours to complete the degreasing and preliminary carbonization treatment, resulting in a porous preform unit.

[0059] (4) Preparation of adhesive slurry and precision bonding of raw blank: Prepare the reactive adhesive slurry: The slurry comprises 60 wt.% submicron silicon carbide powder (D50 = 0.8 μm), 25 wt.% silica sol, 10 wt.% sucrose, and 5 wt.% polyvinyl butyral. Ball mill the above components to form a homogeneous slurry, controlling the viscosity to approximately 15000 mPa·s. Using a precision alignment fixture, align two cleaned and degreased cover plate blanks, uniformly apply the adhesive slurry, press them together, and cure at 80°C for 2 hours to set.

[0060] (5) Integrated reaction sintering: The bonded monolithic blank and an appropriate amount of silicon source were placed in a high-vacuum sintering furnace, and the temperature was increased to 700℃ at a rate of 2℃ / min, held for 1.5 hours to fully decompose residual organic matter; then the temperature was increased to 1600℃ at a rate of 5℃ / min, and sintered in a vacuum environment (≤10 -2 The furnace is held at a constant temperature for 2 hours to allow for the infiltration and reaction sintering of gaseous silicon. The furnace is then cooled to room temperature to obtain the electrostatic chuck base component.

[0061] (6) Performance testing: The fabricated base component was tested. Helium mass spectrometry leak detection showed that all internal cooling channels were well sealed. Interfacial shear strength testing showed a strength value >95 MPa, with the fracture located in the matrix. After 100 thermal cycles from room temperature to 1200°C, the bonded interface remained intact. Scanning electron microscopy showed no visible gaps at the bonded interface. Interfacial elemental distribution showed that Si and C elements were continuous and uniform at the interface.

[0062] Comparative Example 1 This comparative example uses the same preparation process as Example 2, except that the adhesive slurry used in step (4) consists of 80 wt.% submicron silicon carbide powder (D50=0.8μm) and 20 wt.% phenolic resin ethanol solution. This slurry does not contain any form of silicon source, and after curing and carbonization, the adhesive layer mainly consists of silicon carbide particles and amorphous carbon generated by the pyrolysis of phenolic resin.

[0063] Performance Testing: Helium mass spectrometry leak detection indicated that all internal cooling channels were well-sealed. Interfacial shear strength testing showed a strength of approximately 65 MPa, with the fracture occurring entirely along the bond interface, exhibiting brittle fracture. After 100 thermal cycles from room temperature to 1200°C, visible microcracks appeared at the bond interface. Scanning electron microscopy revealed significant micron-sized gaps at the bond interface. Energy dispersive spectroscopy analysis showed a continuous carbon-rich layer in the interface region, with discontinuous Si element distribution, indicating hindered silicon penetration and the absence of an effective new silicon carbide bonding phase at the interface.

[0064] The comparative experimental results show that even under identical process conditions, the lack of a silicon source in the adhesive slurry prevents effective densification and chemical bonding of the interface during subsequent reaction sintering. The adhesive interface is essentially a weakly bonded layer composed of silicon carbide particles and carbon, with insufficient sintering. Its mechanical properties, sealing reliability, thermal stability, and microstructure are all far below the levels achieved in Example 2 of this invention.

[0065] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the scope of protection of this invention.

Claims

1. A method for preparing a closed silicon carbide ceramic component, characterized in that, Includes the following steps: S1. Divide the three-dimensional digital model of the target closed structural component to obtain at least two semi-closed printing units with openings. S2. Using a powder bed-based 3D printing process, silicon carbide preform units for each of the semi-enclosed printing units are prepared respectively. S3. Remove the internal residue from the opening of each green blank unit and then perform degreasing treatment; S4. Use adhesive slurry to align and bond the cleaned green blank units on the mating surface to form an integral green blank. The adhesive slurry contains silicon carbide powder, carbon source and silicon source. S5. The overall green blank is subjected to reaction sintering treatment to allow silicon to penetrate into the green blank matrix and the bonding layer, and react with the carbon source to generate silicon carbide, thereby obtaining a closed silicon carbide ceramic component.

2. The method for preparing a closed silicon carbide ceramic component according to claim 1, characterized in that, In step S1, a positioning docking structure is designed on the split docking surface. The docking structure is selected from at least one of the following: mortise and tenon structure, step structure, and labyrinth groove structure.

3. The method for preparing a closed silicon carbide ceramic component according to claim 1, characterized in that, In step S2, stereolithography or adhesive jetting is used for printing, and the internal cavity is filled with water-soluble or thermally decomposable support material during printing.

4. The method for preparing a closed silicon carbide ceramic component according to claim 3, characterized in that, In step S2, the method for removing internal residues is selected from one of gas purging, liquid flushing, and vibration. The internal residues removed include support material and printing paste / powder.

5. The method for preparing a closed silicon carbide ceramic component according to claim 1, characterized in that, In the adhesive slurry, the silicon source is selected from at least one of micron-sized silicon powder, nano-sized silicon powder, organosilicon compounds, and silica sol.

6. The method for preparing a closed silicon carbide ceramic component according to claim 5, characterized in that, In the adhesive slurry, the molar ratio of carbon to silicon is C:Si = (0.5~2):

1.

7. The method for preparing a closed silicon carbide ceramic component according to claim 1, characterized in that, The particle size of the silicon carbide powder used in the adhesive slurry is smaller than that of the silicon carbide powder used in the green body unit.

8. The method for preparing a closed silicon carbide ceramic component according to claim 1, characterized in that, In step S4, the alignment and bonding specifically includes: with the assistance of positioning fixtures, aligning the mating surfaces of each raw blank unit, uniformly applying the bonding slurry to the mating surfaces, applying pressure to make the raw blank units fit tightly together, and then curing and shaping them.

9. The method for preparing a closed silicon carbide ceramic component according to claim 1, characterized in that, Step S5 specifically includes: placing the entire green blank in a high-temperature sintering furnace, placing an appropriate amount of silicon source around the green blank, heating it to 400~800°C in a vacuum environment, holding it at that temperature for 0.5~2 hours; then heating it to 1400~1650°C, holding it at that temperature for 1~3 hours, to carry out silicon melting and reaction.

10. A closed silicon carbide ceramic component, characterized in that, It is prepared by any one of the preparation methods described in claims 1-9.

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