A method for connecting a silicon carbide ceramic component and a green blank

Abstract

The present invention belongs to the technical field of reaction-sintered SiC ceramics, and discloses a method for connecting a silicon carbide ceramic component to a blank. The steps are as follows: machining a defective part of the reaction-sintered silicon carbide to produce a workpiece to be repaired, using the SiC blank to complement and process a single-degree-of-freedom complementary part, applying an adhesive, connecting by gap fitting, then applying pressure to dry and polish, contacting the sintered body in the connecting part with a sufficient Si source, sintering in a specific environment, and finishing after treatment to obtain a SiC ceramic component. The present invention controls the accuracy and margin by gap fitting the complementary part of the blank, utilizes the dynamic principle of capillary force adsorbing free Si in the SiC sintered body and the Si source continuously replenishing the sintered body, and achieves the effect of improving purity and densification through homogeneous reaction connection, making the connection of the sintered body and the blank a reality, improving the utilization rate of high-purity SiC ceramic components for semiconductor equipment, avoiding repeated preparation processes, and being easy to operate and simple in process.

Description

Technical Field

[0001] The invention relates to the technical field of reaction-sintered SiC ceramics, in particular to a method for connecting a silicon carbide ceramic component and a green blank. Background Art

[0002] Reaction sintered SiC has been widely used in the field of semiconductor front-end process equipment due to its advantages such as high densification and purity, excellent physical and chemical properties, fast reaction speed, low cost, unchanged component size before and after sintering, and ability to produce products with complex shapes.

[0003] As key components in integrated circuit manufacturing equipment, SiC precision components come into direct or indirect contact with wafers, placing high demands on material purity, density, and physical and chemical properties, particularly the absence of any defects. In the process of manufacturing SiC ceramic components using reaction sintering, improper finishing techniques, sintering temperature control, or usage can easily lead to defects such as porosity, pores, cracks, surface corrosion, and fatigue, rendering the product useless. For precision components with complex structures, repeated preparation processes are cumbersome, difficult to process, and time-consuming, labor-intensive, resulting in significant waste. Effectively connecting and repairing defective SiC ceramic components can directly improve material utilization and product qualification rates.

[0004] At present, the main connection processes for silicon carbide ceramics include brazing, diffusion welding, glass solder method, reaction connection method, and bonding method. Among them, reaction connection forms SiC as an intermediate layer through Si-C reaction, which does not have the problem of thermal expansion coefficient mismatch and is an ideal connection method. However, patent CN110790586A believes that due to the influence of thermodynamic factors or multiple sintering, defects will be concentrated in the core, that is, the Si content in the SiC after reaction sintering has reached saturation. Secondary sintering will cause the Si inside the ceramic, especially in the core, to volatilize and lose, resulting in loose defects in the core of the SiC ceramic after sintering, which will affect the mechanical properties and surface accuracy of the material.

[0005] Therefore, it is particularly important to use a simpler and more effective method to effectively connect and repair SiC ceramic component products to avoid Si volatilization loss during secondary sintering, which in turn affects the mechanical properties and surface accuracy of the material. Summary of the Invention

[0006] In response to the above technical problems, the present invention proposes a method for connecting silicon carbide ceramic components and blanks. By machining defective parts and single-degree-of-freedom complementary parts, and then sintering again after connection, the material utilization rate and product qualification rate are directly improved, and repeated preparation steps are avoided. The operation is easy and the process is simple.

[0007] To achieve the above object, the technical solution of the present invention is implemented as follows:

[0008] A method for connecting a silicon carbide ceramic component to a green blank, comprising the following steps:

[0009] S1: Machining a specific shape of the defective part of the silicon carbide ceramic component to obtain a repaired workpiece;

[0010] S2: Use SiC blank matching machine to add single degree of freedom complementary parts;

[0011] S3: Apply pre-mixed adhesive, connect the workpiece to be repaired and the complementary part to obtain a connecting part, press dry the connecting part, polish it, contact it with sufficient Si source and sinter it again, clean it and then finish it to obtain a qualified SiC ceramic component product.

[0012] Furthermore, the machining accuracy in step S1 is ±0.1 mm, and the surface roughness Ra of the workpiece to be repaired needs to be 0.8-3.2 to facilitate the fitting and the specific shape to match the complementary part.

[0013] Furthermore, the single-degree-of-freedom complementary part in step S2 is loosely fitted with the workpiece to be repaired, and protrudes from the workpiece to be repaired after fitting.

[0014] Furthermore, the binder in step S3 may be in the form of a paste, an emulsion, or a suspension, and the binder includes 15%-35% of a thermoplastic resin, 20%-40% of SiC powder, 3%-7% of carbon black, and the balance being an organic solvent.

[0015] Furthermore, the thermoplastic resin is at least one of silicone resin, phenolic resin, and acrylic resin; the SiC powder gradation should be the same as the SiC gradation when the original ceramic component is formed; the carbon black is submicron-grade and modified by polyethylene glycol dispersion, with a particle size of 0.5 μm; and the organic solvent contains polyethylene glycol and ethanol.

[0016] Furthermore, the "pressurizing" in step S3 refers to applying a pressure of 0.1-10 MPa at the connection position on the connector, "drying" refers to standing at room temperature for 48-60 hours or keeping warm in a drying oven environment at 60-80°C for 4-6 hours to solidify the connecting layer, and polishing refers to removing the excess on the complementary part blank after connection.

[0017] Furthermore, in step S3, "contacting with sufficient Si source" means providing sufficient elemental Si powder, Si particles or Si blocks, and only contacting the sintered body part in the connector, not contacting the blank or connecting layer in the connector, and BN barrier protection can be applied.

[0018] Furthermore, the "secondary sintering" in step S3 refers to a vacuum environment at a temperature of 1470-1570°C for 1-3 hours. At temperatures above the melting point of Si, the furnace pressure should be kept above the saturated vapor pressure at Si's highest sintering temperature to prevent the loss of liquid Si from the material through vaporization. Ultimately, the green body continuously absorbs free Si from the SiC sintered body, reacting and infiltrating the connecting layer, while the Si source continuously replenishes the sintered body, achieving uniform densification without compromising surface precision.

[0019] The principle of forming dense and high-purity ceramics is that molten Si enters the SiC blank under the combined action of temperature gradient thermodynamics and capillary force dynamics. Subsequently, under the further promotion of reaction kinetics of residual C in the blank, "reaction infiltration" occurs and secondary SiC is generated. A small amount of free Si fills the remaining pores. When cooled, the free Si produces 10.9% recrystallization expansion, releasing the internal stress to the surface, and finally forming dense and high-purity Si / SiC composite ceramics.

[0020] The beneficial effects produced by the present invention are:

[0021] (1) The present invention provides a method for connecting a silicon carbide ceramic component to a blank. By machining defective parts and single-degree-of-freedom complementary parts, and then re-sintering after connection, the defects of the reaction-sintered SiC material are effectively repaired. By controlling the gas pressure in the furnace during the re-sintering process, when the temperature is higher than the melting point of Si, it is made higher than the saturated vapor pressure at the highest sintering temperature of Si, so as to prevent the gasification loss of liquid Si in the material. Ultimately, the blank continuously absorbs free Si in the SiC sintered body and reacts and infiltrates with the connecting layer, and the Si source continuously replenishes the sintered body, achieving the purpose of uniform densification without affecting the surface accuracy, thereby ensuring the mechanical properties and surface accuracy after connection.

[0022] (2) The method for connecting a silicon carbide ceramic component to a blank provided by the present invention controls precision and margin by gap-fitting complementary blank parts. It utilizes the dynamic principle of capillary force adsorption of free Si from the SiC sintered body and the continuous replenishment of the Si source to the sintered body, achieving the effect of improving purity and densification through homogeneous reaction connection. Molten Si enters the SiC blank under the combined action of temperature gradient thermodynamics and capillary force dynamics. Subsequently, further promoted by the reaction dynamics of residual C in the blank, "reaction infiltration" occurs and secondary SiC is generated. A small amount of free Si fills the remaining pores. When cooled, the free Si undergoes a 10.9% recrystallization expansion, releasing internal stress to the surface, ultimately forming a dense, high-purity Si / SiC composite ceramic.

[0023] (3) The present invention provides a method for connecting a silicon carbide ceramic component to a green body, making it possible to connect a sintered body to a green body. By connecting the green body to the sintered body, defective silicon carbide ceramic components can be repaired, directly improving material utilization and product qualification rates, avoiding repeated preparation steps, and making the process easy to operate and simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 It is a schematic diagram of the connection between the complementary parts that should be set for different defects of silicon carbide ceramic component products and the silicon carbide ceramic component products.

[0026] Figure 2 It is a schematic diagram of the sintering method after the connection of the silicon carbide ceramic sintered body component and the green green complementary part.

[0027] Figure 3 A photo of a silicon carbide ceramic component (vacuum chuck base) and its defect location (a) and the repaired ceramic component (b).

[0028] Figure 4 These are macroscopic pictures of the furnace sample silicon carbide sintered body-green blank connection sample of Example 1 after re-sintering, where (a) is before polishing and (b) is after polishing.

[0029] Figure 5 This is a metallographic photograph of the connecting layer area of the furnace sample of Example 1.

[0030] Figure 6 This is a metallographic photograph of the connecting layer area of the furnace sample of Example 4.

[0031] Figure 7 This is a metallographic photograph of the connecting layer area of the furnace sample of Example 5. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The present invention provides a method for connecting a silicon carbide ceramic component to a blank, specifically, the method includes machining a specific shape on the defective part of the ceramic component to obtain a workpiece to be repaired; using a SiC blank repair machine to add a single degree of freedom complementary part; connecting the workpiece to be repaired and the single degree of freedom complementary part by an adhesive, and adopting a clearance fit connection method. The connection structure of the degree of freedom complementary part and the workpiece to be repaired is as follows: Figure 1 Then, it is sintered again after contacting with sufficient Si source, and then cleaned and finely processed to obtain SiC ceramic component products. Among them, the Si source only contacts the sintered body part in the connecting part, and does not contact the green body or connecting layer in the connecting part ( Figure 2 The green body and the connecting layer can be coated with BN for permeation resistance. By gradually increasing the furnace pressure above the Si melting point to a level above the saturated vapor pressure of Si at the sintering temperature, this prevents the vaporization and loss of liquid Si in the material. Ultimately, the green body continuously absorbs free Si from the SiC sintered body, reacting and infiltrating the connecting layer, while the Si source continuously replenishes the sintered body, achieving uniform densification without compromising surface accuracy.

[0034] Example 1

[0035] The method for connecting the silicon carbide ceramic component and the green blank in this embodiment comprises the following steps:

[0036] A reaction-sintered silicon carbide vacuum chuck base for a photolithography machine, measuring 332 mm x 21 mm, had a large crack (18 mm) on its side. This defect was machined into an arched column with an R5 height of 21 mm and a roughness of 0.8, resulting in the workpiece to be repaired. A complementary single-degree-of-freedom part with the same radius and a height of 22 mm was also machined from the SiC blank. An adhesive consisting of 25% phenolic resin, 30% silicon carbide micropowder, 5% carbon black, 5% polyethylene glycol, and 35% ethanol was applied and gap-fitted to the workpiece to be repaired. After applying a pressure of 6 MPa, the base was dried at room temperature for 48 hours, and the complementary part was polished to the desired dimensions and accuracy. The connector was placed in a vacuum environment, a sufficient amount of Si powder was placed on the chuck base, and the product was sintered at 1550°C for 2 hours. When the temperature reached 1400°C, Ar gas was introduced to raise the furnace pressure to 90 Pa (the saturated vapor pressure of Si at 1550°C is 32 Pa). After cooling to room temperature, the furnace was cleaned and finely processed to obtain qualified SiC ceramic components. Furthermore, the furnace sample of this example also consisted of two parts (reaction-sintered silicon carbide and SiC green blank), and the roughness of the sintered silicon carbide to be repaired was 0.8. They were then joined using the same process conditions.

[0037] The furnace samples and the product were tested according to the methods of GB / T 6569 "Test method for flexural strength of fine ceramics", GB / T 3045 "Chemical analysis method of silicon carbide as a common abrasive" and GB / T 13841 "Surface roughness of electronic ceramic parts".

[0038] Three-point bending tests showed that the average bending strength of 12 3*4*40mm specimens in the parent material area was 344.6MPa. The fracture surface of the connecting layer, positioned at different locations, was located in the center of the specimen. The average bending strength of the 12 specimens was 342MPa, indicating that the mechanical properties of the connecting layer and the parent material are basically consistent. The surface roughness was less than Ra0.8, and the surface accuracy after fine machining met the design requirements.

[0039] Figure 3 Photos of the silicon carbide vacuum chuck base and its defective location (a) and the ceramic component after repair (b) are shown. Macroscopically, the vacuum chuck connected using this method shows virtually no signs of repair, and the connection is essentially identical before and after, demonstrating excellent results.

[0040] Figure 4 The following are macroscopic images of the furnace sample (sintered body-green blank connection) after re-sintering in this example. (a) is before polishing, and the cross section of the connection layer is not obvious macroscopically. After polishing (b), a bright line can be barely seen with the naked eye, which is caused by the Si pool. Figure 5 This is a metallographic photograph of the connecting layer area of the sample. Microscopically, the connecting layer is 80μm wide. The connecting surface on the sintered body side is smoother, and the connecting surface on the green body side is rougher. The carbon black in the binder reacts thoroughly to generate a large amount of fine secondary SiC. The connecting effect is good, and the microstructure of the connecting layer and the base material are basically consistent.

[0041] Example 2

[0042] The method for connecting the silicon carbide ceramic component and the green blank in this embodiment comprises the following steps:

[0043] A reaction-sintered silicon carbide ceramic component, measuring 250 mm x 30 mm, contained a bubble on a boss. The defect was machined to create a parallelogram with upper and lower bases of 3 mm and 5 mm sides, respectively, and a quadrangular prism 8 mm high, with a roughness of Ra 1.6, resulting in the workpiece to be repaired. Simultaneously, the SiC blank was machined into a single-degree-of-freedom complementary component with a matching shape, projecting beyond the workpiece after mating. An adhesive consisting of 30% acrylic resin, 25% silicon carbide powder, 3% carbon black, 2% polyethylene glycol, and 40% ethanol was applied and gap-fitted to the workpiece and complementary component. A pressure of 1 MPa was applied using a fixture clamp, and the components were placed in a 60°C drying oven for 6 hours before being polished to the desired dimensions and accuracy. The connector was placed in a vacuum environment, and a sufficient amount of Si blocks were placed on the ceramic component, followed by sintering at 1500°C for 2 hours. When the temperature reached 1400°C, the vacuum pump was turned off and the furnace pressure slowly increased to 50 Pa (the saturated vapor pressure of Si at 1500°C is 18 Pa). This pressure was then maintained by repeatedly turning the vacuum pump on and off. After cooling to room temperature, the repaired SiC ceramic component was cleaned and finely processed. Furthermore, the furnace sample of this example also consisted of two parts (reaction-sintered silicon carbide and SiC green blank), with the roughness of the sintered silicon carbide to be repaired being 1.6. The components were then joined using the same process conditions.

[0044] The furnace samples were tested according to the methods of GB / T 6569 "Test method for flexural strength of fine ceramics", GB / T 3045 "Chemical analysis method of silicon carbide as a common abrasive" and GB / T 13841 "Surface roughness of electronic ceramic parts".

[0045] Three-point bending tests showed that the average bending strength of 12 3*4*40mm specimens in the parent material area was 343MPa. The fracture surface of the connecting layer was located in different positions, and the average bending strength of the 12 specimens was 340MPa, indicating that the mechanical properties of the connecting layer and the parent material are basically consistent. The surface roughness is less than Ra0.8, and the surface accuracy after fine machining meets the design requirements.

[0046] Example 3

[0047] The method for connecting the silicon carbide ceramic component and the green blank in this embodiment comprises the following steps:

[0048] A reaction-sintered silicon carbide ceramic component, measuring 250 mm x 30 mm, contained a bubble on a boss. A single-degree-of-freedom (DOF) complementary component blank was machined, with upper and lower base diameters of 3 mm and 5 mm, respectively, and a height of 8 mm. The roughness Ra reached 3.2, resulting in the workpiece being repaired. Simultaneously, the SiC blank was machined into a single-degree-of-freedom (DOF) complementary component with a matching shape, projecting beyond the workpiece after mating. An adhesive consisting of 25% phenolic resin, 30% silicon carbide micropowder, 5% carbon black, 5% polyethylene glycol, and 35% ethanol was applied and gap-fitted to the workpiece and complementary component. After applying a pressure of 0.1 MPa and drying at room temperature for 60 hours, the complementary component was polished to the desired dimensions and precision. The connector was placed in a vacuum environment, a sufficient amount of Si powder was placed on a suction cup base, and sintered at 1470°C for 3 hours. When the temperature reached 1400°C, Ar gas was introduced to raise the furnace pressure to 50 Pa (the saturated vapor pressure of Si at 1470°C is 14 Pa). After cooling to room temperature, the furnace was cleaned and finely processed to obtain qualified SiC ceramic components. Furthermore, the furnace sample of this example also consisted of two parts (reaction-sintered silicon carbide and SiC green blank), and the roughness of the sintered silicon carbide to be repaired was 3.2. They were then joined using the same process conditions.

[0049] The furnace samples were tested according to the methods of GB / T 6569 "Test method for flexural strength of fine ceramics", GB / T 3045 "Chemical analysis method of silicon carbide as a common abrasive" and GB / T 13841 "Surface roughness of electronic ceramic parts".

[0050] Analysis of the qualified SiC ceramic components and accompanying furnace samples revealed that the flexural strength of both the base material and the bonding layer was 340 MPa. The bonding layer was approximately 85 μm wide, likely due to the low pressure. The surface roughness was < Ra 0.8, and the surface accuracy after fine machining met the design requirements. The results were essentially identical to those in Example 1, with minor discrepancies likely due to systematic errors.

[0051] Example 4

[0052] The method for connecting the silicon carbide ceramic component and the green blank in this embodiment comprises the following steps:

[0053] A reaction-sintered silicon carbide vacuum chuck base for a photolithography machine, measuring 332 mm x 21 mm, had a large crack (18 mm) on its side. A 21 mm high, arched column with a roughness of Ra 0.8 was machined to create the workpiece to be repaired. A complementary single-degree-of-freedom part with the same radius and a height of 22 mm was also machined from the SiC blank. An adhesive consisting of 15% phenolic resin, 20% silicon carbide micropowder, 3% carbon black, 5% polyethylene glycol, and 57% ethanol was applied and gap-fitted to the workpiece to be repaired. A pressure of 10 MPa was applied, the parts were placed in an 80°C drying oven for 4 hours, and then polished to the desired dimensions and accuracy. The connector was placed in a vacuum environment, a sufficient amount of Si powder was placed on the chuck base, and the parts were sintered at 1570°C for 1 hour. When the temperature reached 1400°C, Ar gas was introduced to raise the furnace pressure to 90 Pa (the saturated vapor pressure of Si at 1570°C is 32 Pa). After cooling to room temperature, the furnace was cleaned and finely processed to obtain a qualified SiC ceramic component. Furthermore, the furnace sample of this example also consisted of two parts (reaction-sintered silicon carbide and SiC green blank), and the roughness of the sintered silicon carbide to be repaired was 0.8. They were then joined using the same process conditions.

[0054] The furnace samples were tested according to the methods of GB / T 6569 "Test method for flexural strength of fine ceramics", GB / T 3045 "Chemical analysis method of silicon carbide as a common abrasive" and GB / T 13841 "Surface roughness of electronic ceramic parts".

[0055] The three-point bending test showed that when the connecting layer was set at different positions, the fracture was in the middle of the sample. The average bending strength of the 12 samples was 290 MPa, and the surface roughness was < Ra0.8. Figure 6 This is the metallographic structure of the furnace sample of this embodiment. It can be seen from the figure that due to the low C source content and the low SiC solid content in the binder, a large amount of free Si or Si pools appeared in the connecting layer, and there were fewer SiC particles, which could not effectively hinder the expansion of cracks.

[0056] Example 5

[0057] The method for connecting the silicon carbide ceramic component and the green blank in this embodiment comprises the following steps:

[0058] A reaction-sintered silicon carbide vacuum chuck base for a photolithography machine, measuring 332 mm x 21 mm, had a large crack (18 mm) on its side. This defect was machined into an arched column with an R5 height of 21 mm and a roughness of 0.8, resulting in the workpiece to be repaired. A complementary single-degree-of-freedom part with the same radius and a height of 22 mm was also machined from the SiC blank. An adhesive consisting of 35% phenolic resin, 40% silicon carbide powder, 7% carbon black, 1% n-butanol, and 17% ethanol was applied and gap-fitted to the workpiece to be repaired. After applying a pressure of 6 MPa, the base was dried at room temperature for 48 hours, and the complementary part was polished to the desired dimensions and accuracy. The connector was placed in a vacuum environment, a sufficient amount of Si powder was placed on the chuck base, and the product was sintered at 1550°C for 2 hours. When the temperature reached 1400°C, Ar gas was introduced to raise the furnace pressure to 90 Pa (the saturated vapor pressure of Si at 1550°C is 32 Pa). After cooling to room temperature, the furnace was cleaned and finely processed to obtain qualified SiC ceramic components. Furthermore, the furnace sample of this example also consisted of two parts (reaction-sintered silicon carbide and SiC green blank), and the roughness of the sintered silicon carbide to be repaired was 0.8. They were then joined using the same process conditions.

[0059] The furnace samples were tested according to the methods of GB / T 6569 "Test method for flexural strength of fine ceramics", GB / T 3045 "Chemical analysis method of silicon carbide as a common abrasive" and GB / T 13841 "Surface roughness of electronic ceramic parts".

[0060] The three-point bending test shows that when the connecting layer is set at different positions, the fracture mainly occurs in the base material area. The average bending strength of the 12 specimens is 350 MPa, and the surface roughness is less than Ra0.8. Figure 7 This is the metallographic structure of the furnace sample of this embodiment. It can be seen from the figure that due to the excessive C source, a large number of small particles of secondary SiC are generated in the connecting layer, which effectively hinders the expansion of cracks, resulting in the connecting layer strength being slightly stronger than the base material.

[0061] Comparative Example 1

[0062] The method for connecting the silicon carbide ceramic component to the green blank in this comparative example differs from that in Example 1 in that, when the temperature is higher than 1400°C, vacuum is continuously drawn by a Roots pump to reduce the pressure in the furnace to 20 Pa, which is lower than the saturated vapor pressure of Si at 1550°C (32 Pa). The specific steps are as follows:

[0063] A reaction-sintered silicon carbide vacuum chuck base for a photolithography machine, measuring 332mm x 21mm, had a large crack (18mm) on its side. This defect was machined into an arched column with an R5 height of 21mm and a roughness of Ra0.8. A complementary single-degree-of-freedom part with the same radius and a height of 22mm was also machined from the SiC blank. A bonding agent consisting of 25% phenolic resin, 30% silicon carbide micropowder, 5% carbon black, 5% polyethylene glycol, and 35% ethanol was applied and gap-fitted to the workpiece being repaired and the complementary part. After applying a pressure of 6MPa, the workpiece was dried at room temperature for 48 hours, and the complementary part was polished to the desired dimensions and accuracy. The connecting part was placed in a vacuum environment, a sufficient amount of Si powder was placed on the chuck base, and the product was sintered at 1550°C for 2 hours. When the temperature reached 1400°C, Ar gas was introduced to raise the furnace pressure to 20 Pa (the saturated vapor pressure of Si at 1550°C is 32 Pa). After cooling to room temperature, the furnace was cleaned and fine-machined to produce qualified SiC ceramic components. The final repaired suction cup base sample, which was sent to the furnace with the furnace, showed a loose core, poor surface morphology, and fell short of the machining accuracy standards.

[0064] Comparative Example 2

[0065] The method for connecting the silicon carbide ceramic component to the green body in this comparative example is different from that in Example 1 in that the silicon source is in direct contact with the green body and the connecting layer in the connecting member, rather than with the sintered body. The specific steps are as follows:

[0066] A reaction-sintered silicon carbide vacuum chuck base for a photolithography machine, measuring 332 mm x 21 mm, had a large crack (18 mm) on its side. This defect was machined into an arched column with an R5 height of 21 mm and a roughness of Ra 0.8. A complementary single-degree-of-freedom part with the same radius and a height of 22 mm was also machined from the SiC blank. A bonding agent consisting of 25% phenolic resin, 30% silicon carbide powder, 5% carbon black, 5% polyethylene glycol, and 35% ethanol was applied and gap-fitted to the workpiece being repaired and the complementary part. After applying a pressure of 6 MPa, the parts were dried at room temperature for 48 hours, and the complementary part was polished to the desired dimensions and accuracy. The connector was placed in a vacuum environment, with the Si powder in direct contact with the blank and the connecting layer, and then sintered at 1550°C for 2 hours. When the temperature reached 1400°C, Ar gas was introduced to raise the furnace pressure to 90 Pa (the saturated vapor pressure of Si at 1550°C is 32 Pa). After cooling to room temperature, the components were cleaned and finished to obtain qualified SiC ceramic parts. However, the Si in the connecting layer was not fully impregnated, resulting in defects such as pores, and the bonding or repair effect was not achieved.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for connecting a silicon carbide ceramic component to a green blank, characterized in that: Here are the steps: S1: machining the defective part of the silicon carbide ceramic component to obtain a repaired workpiece; S2: Use SiC blank matching machine to add single degree of freedom complementary parts; S3: Connecting the workpiece to be repaired and the single-degree-of-freedom complementary part by applying an adhesive to obtain a connected part; S4: After being pressed, dried and polished, the connector is contacted with the Si source and sintered again. After cleaning and fine processing, a qualified SiC ceramic component product is obtained. Herein, contact with the Si source means that the Si source only contacts the sintered body part of the connector, and does not contact the blank or connecting layer in the connector. The conditions for re-sintering are: sintering at a temperature of 1470-1570℃ in a vacuum environment for 1-3h. When the temperature reaches 1400℃, the gas pressure in the furnace is increased to make the gas pressure higher than the saturated vapor pressure of the Si sintering temperature.

2. The method for connecting a silicon carbide ceramic component to a green body according to claim 1, characterized in that: The machining accuracy in step S1 is ±0.1 mm, and the surface roughness Ra of the workpiece to be repaired is 0.8-3.

2.

3. The method for connecting a silicon carbide ceramic component to a green body according to claim 2, characterized in that: In step S2, the single-degree-of-freedom complementary part is loosely fitted with the workpiece to be repaired, and protrudes from the workpiece to be repaired after fitting.

4. The method for connecting a silicon carbide ceramic component to a green body according to claim 3, characterized in that: In step S3, the binder is in the form of a paste, an emulsion or a suspension.

5. The method for connecting a silicon carbide ceramic component to a green body according to claim 1 or 4, characterized in that: In step S3, the binder includes 15%-35% thermoplastic resin, 20%-40% SiC powder, 3%-7% carbon black, and the balance is organic solvent.

6. The method for connecting a silicon carbide ceramic component to a green body according to claim 5, characterized in that: The thermoplastic resin is at least one of silicone resin, phenolic resin, and acrylic resin; the SiC powder gradation should be the same as the SiC gradation when the original ceramic component is formed; the carbon black is submicron-grade and modified by polyethylene glycol dispersion, with a particle size of 0.5 μm; the organic solvent contains polyethylene glycol and ethanol.

7. The method for connecting a silicon carbide ceramic component to a green body according to claim 5, characterized in that: In step S4, applying pressure refers to applying a pressure of 0.1-10 MPa at the connection position on the connector; drying refers to standing and drying at room temperature or baking to solidify the connection layer; and polishing refers to removing the excess on the blank of the complementary part after connection.

8. The method for connecting a silicon carbide ceramic component to a green body according to claim 7, characterized in that: In step S4, the Si source is elemental Si powder, Si particles or Si blocks.

Images