Connection method of silicon carbide material and silicon carbide ceramic connection joint

Abstract

The invention relates to the technical field of ceramic material processing, in particular to a connection method of a silicon carbide material and a silicon carbide ceramic connection joint. The connecting method of the silicon carbide material comprises the steps that inorganic glue is applied to the surfaces of two silicon carbide base materials to be welded, the surfaces, coated with the inorganic glue, of the two silicon carbide base materials to be welded are glued, and a glued joint is obtained; wherein the inorganic glue is prepared from the following components: SiO2, Ti H2, Si C and graphene; and carrying out spark plasma sintering on the glued joint to obtain the silicon carbide ceramic joint. The method has the effect of improving the high-temperature resistance of the silicon carbide material connection joint.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic material processing, and in particular, to a connection method for silicon carbide materials and a silicon carbide ceramic connection joint. Background Art

[0002] SiC ceramic matrix composites are widely used due to their high strength, high hardness, high modulus, low coefficient of thermal expansion, good thermal shock resistance, excellent high-temperature oxidation and corrosion resistance, etc. Currently, the preferred manufacturing technology for large-sized complex SiC ceramic matrix composite structural parts is to manufacture each component separately and then further assemble and connect them. In order to ensure the stability of the connection of complex components of SiC ceramic matrix composites and the application of large and complex integral component products, it is necessary to ensure that the connection joint has good high-temperature performance and sealed connection.

[0003] Currently, a series of assembly and connection methods for SiC ceramic matrix composites, such as brazing and diffusion bonding, require high-temperature and high-pressure test conditions, which easily lead to large residual stresses in the joints, and high temperatures will exacerbate the metallurgical reactions inside the joints, resulting in the formation of a large amount of brittle intermetallic compounds. Under high-temperature service conditions, these brittle intermetallic compounds are prone to generating microcracks, leading to crack propagation during service and thus triggering catastrophic accidents. Summary of the Invention

[0004] The present invention aims to improve the high-temperature performance of the connection joint of silicon carbide materials.

[0005] To solve the above problems, as a first aspect, the present invention provides a connection method for silicon carbide materials, including:

[0006] Coating an inorganic glue on the surfaces of two silicon carbide base materials to be welded, and bonding the surfaces of the two silicon carbide base materials to be welded coated with the inorganic glue to obtain a bonded joint; wherein, the inorganic glue includes the following components: SiO2, TiH2, SiC and graphene;

[0007] Performing spark plasma sintering on the bonded joint to obtain a silicon carbide ceramic connection joint.

[0008] Optionally, in the inorganic glue, the molar ratio of SiO2, TiH2, SiC and graphene is (0.5 to 1):(3 to 3.5):(0.5 to 1):(1.5 to 2).

[0009] Optionally, the bonding of the surfaces of the two silicon carbide base materials to be welded coated with the inorganic glue includes: the bonding pressure is 1 to 5 MPa.

[0010] Optionally, bonding the surfaces of the two silicon carbide base materials to be welded coated with the inorganic glue includes: the bonding temperature is 50 to 120 °C, and the heat preservation time is 4 to 8 h.

[0011] Optionally, subjecting the bonded joint to spark plasma sintering includes: the sintering temperature is 1100 to 1500 °C, the sintering pressure is 10 to 20 MPa, and the sintering time is 15 to 30 min.

[0012] Optionally, the heating rate of the spark plasma sintering is 100 to 110 °C / min.

[0013] Optionally, the preparation method of the inorganic glue includes:

[0014] Mix SiO2, TiH2, SiC and graphene evenly, and at the same time add grinding balls and a dispersion solvent for ball milling to obtain a mixed slurry. Dry and grind the mixed slurry to obtain a composite powder;

[0015] Mix the composite powder and an adhesive evenly to obtain the inorganic glue.

[0016] Optionally, the adhesive is an aqueous solution of Na2SiO3 or a solution of sodium aluminosilicate.

[0017] Optionally, the molar ratio of SiO2 in the composite powder to the adhesive is 2:3 to 3:2.

[0018] As a second aspect, the present invention also provides a silicon carbide ceramic connection joint, which is prepared by using the connection method of the silicon carbide material as described above.

[0019] The beneficial effects of the present invention compared with the prior art are:

[0020] The present invention couples the bonding of silicon carbide materials with spark plasma sintering (SPS). First, the sintering powder TiH2 is added to the silicate-based inorganic glue. After low-temperature curing, a three-dimensional MAX phase, namely the three-dimensional high-temperature resistant ceramic skeleton Ti3SiC2, is in-situ generated in the joint by using the spark plasma sintering process, thereby improving its high-temperature resistant performance. The welding rate of the silicon carbide joint prepared by using the connection process of the present invention reaches more than 95%, the room-temperature shear strength is above 50 MPa, the high-temperature (1500 °C) shear strength is above 20 MPa, and the helium leakage rate after sealing is ≤ 10 -10 Pa m 3 / s. Description of the Drawings

[0021] Figure 1 It is a flowchart of the connection method of the silicon carbide material in the exemplary embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the connection body to be welded in Embodiment 1 of the present invention. Detailed implementation manners

[0023] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following provides a detailed description of specific embodiments of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used in the description of this application in the specification are only for the purpose of describing specific implementation manners and are not intended to limit this application;

[0025] As used herein, the term "including" and its variations are open-ended, that is, "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are used to distinguish different objects and are not used to describe a specific order or primary-secondary relationship. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0026] At present, the connection methods of ceramic materials mainly include the following: sintered metal powder method, diffusion welding, brazing, etc. Among them, brazing and diffusion welding require high-temperature and high-pressure test conditions, which easily lead to large residual stresses in the joints. Moreover, high temperatures will exacerbate the metallurgical reactions in the joints, resulting in the formation of a large amount of brittle intermetallic compounds. Under high-temperature service conditions, these brittle intermetallic compounds are prone to generate microcracks, leading to crack propagation during service and thus triggering catastrophic accidents. Taking brazing as an example, AgCuTi filler metal is a commonly used active filler metal. This filler metal utilizes the good reaction activity between Ti and SiC ceramics at high temperatures to solve the problem of difficult welding of SiC ceramics. Ti and SiC ceramics generate TiC and Ti5Si3 compounds at the interface through interfacial chemical reactions, thereby forming a good metallurgical bond. Brazing SiC ceramics with AgCuTi filler metal can obtain relatively high joint strength. However, due to the relatively low melting point of the filler metal, the filler metal layer in the joint is prone to softening during high-temperature service. Therefore, such joints are not suitable for situations where the joint needs to serve at high temperatures. The working temperature of ceramic joints brazed with AgCuTi filler metal is generally only 400 to 500 °C, which limits the high-temperature application of ceramic welded joints.

[0027] An embodiment of the present invention provides a method for connecting silicon carbide materials. Referring to Figure 1 as shown, it includes:

[0028] Step S1: Coat an inorganic glue on the surfaces of two silicon carbide base materials to be welded, and then bond the surfaces of the two silicon carbide base materials coated with the inorganic glue to obtain a bonded joint. Among them, the inorganic glue includes the following components: SiO2, TiH2, SiC, and graphene.

[0029] Step S2: Perform spark plasma sintering on the bonded joint to obtain a silicon carbide ceramic connection joint.

[0030] The bonding technology has the advantage of uniform stress distribution. It can avoid the stress concentration problem caused by traditional mechanical connection without damaging the base material, and can keep the base intact, which is an advantage that traditional technologies cannot provide at present. At the same time, the bonding technology is easy to operate, has a simple preparation process, does not require ultra-high temperature treatment, can be joined at a relatively low temperature, and can provide reliable bonding strength within a wide temperature range.

[0031] According to the application environment and conditions of SiC single crystal and SiC ceramic matrix composites, in order to meet the requirements of high temperature resistance and sealing performance of their connection joints, the key to ceramic material bonding technology lies in developing a sealant that can be cured at low temperature, has less thermal weight loss, and still has good mechanical properties after high temperature heat treatment. Currently, sealants mainly include organic sealants and inorganic sealants. The mechanical properties and bonding strength of inorganic sealants are generally higher than those of organic sealants. During high temperature heat treatment, the thermal weight loss and volume shrinkage of inorganic sealants are much lower than those of organic sealants. Moreover, there is a risk of instantaneous carbonization of organic sealants in transient high temperature service environments. Therefore, inorganic sealants are more suitable for bonding SiC single crystal and SiC ceramic matrix composites.

[0032] Currently, the most widely used inorganic sealants are phosphate-based sealants and silicate-based sealants respectively. The maximum service temperature of phosphate-based sealants is about 900 °C, and the maximum service temperature of silicate-based sealants is about 1000 °C. Therefore, considering the high temperature resistance of the sealant itself and the thermal weight loss caused by component volatilization (phosphorus is volatile), it is more promising to use silicate-based sealants to achieve low temperature sealing and high temperature use of SiC ceramics.

[0033] For the development of high temperature resistant silicate-based sealants, the core lies in how to reduce the heat loss during the high temperature process, reduce the volume shrinkage, and at the same time improve its high temperature strength. Specifically, from the perspective of physical methods, ceramic reinforcing particles can be added to the sealant, which can increase the solid content of the sealant, improve the sealing performance, and relieve volume shrinkage. From the chemical method perspective, the curing agent or adhesive in the sealant can be modified. Modifying and optimizing the composition of the sealant itself can essentially reduce the thermal weight loss of the sealant and improve the high temperature mechanical properties.

[0034] The present invention couples the bonding of silicon carbide materials with spark plasma sintering. First, sintering powder TiH2 is added to the silicate-based inorganic adhesive. After low temperature curing, a three-dimensional MAX phase, namely the three-dimensional high temperature resistant ceramic framework Ti3SiC2, is in-situ generated in the joint by using the spark plasma sintering process, thereby improving its high temperature resistance. The welding rate of the silicon carbide joint prepared by the connection process of the present invention reaches more than 95%, the room temperature shear strength is above 50 MPa, the high temperature (1500 °C) shear strength is above 20 MPa, and the helium leakage rate after sealing is ≤ 10 -10 Pa m 3 / s.

[0035] The MAX phase is a new type of nano-layered ternary carbide or nitride material, with the chemical general formula M n +1AX n, where M represents a transition metal element, A is mainly an element in Group IIIA or Group IVA of the periodic table, X is C and / or N, and n is generally 1, 2, or 3, corresponding to 211, 312, and 413 type MAX phases respectively. As a class of processable nano-layered materials, the special combination of element types and laminated structure of MAX phases endows them with both excellent ceramic and metal properties. In the crystal structure of MAX phases, the M-site atoms and X-site atoms are closely packed in octahedral positions, forming a strongly covalent M n +1X n strong covalent bond layer, and the M n +1X n layers are separated by weakly metallic bond A layers with metallic properties. Due to the unique bonding structure, MAX phases possess both ceramic and metal properties. On the one hand, they are hard, lightweight, easy to machine and cut, and also have excellent ceramic characteristics such as oxidation resistance, high temperature resistance, and creep resistance; on the other hand, they have a relatively large density of states at the Fermi level, which is dominated by the d-d orbitals of the M element, making their electrical conductivity higher than that of pure M metals in some cases, showing good electrical and thermal conductivity and excellent damage tolerance and other excellent metal-like characteristics. Specifically, in the process of spark plasma sintering in the present invention, the following reactions occur among TiH2, SiC, and graphene powders:

[0036] TiH2 → Ti + 2H

[0037] 3Ti + SiC + C → Ti3SiC2

[0038] TiH2, SiC, and graphene powders generate a three-dimensional MAX phase, namely a three-dimensional high-temperature resistant ceramic framework Ti3SiC2, which can improve the high-temperature resistance of the adhesive joint. While applying pressure to the adhesive joint, the sample is directly heated by a direct current pulse current flowing through the interior of the sample, triggering phenomena such as spark plasma and local Joule heat, thereby realizing the low-temperature rapid sintering of the material. Compared with traditional heat treatment, spark plasma sintering is faster, which further promotes the densification of the inorganic glue and further improves the densification of the joint.

[0039] In some alternative embodiments, in the inorganic glue of step S1, the molar ratio of SiO2, TiH2, SiC, and graphene is (0.5 to 1):(3 to 3.5):(0.5 to 1):(1.5 to 2).

[0040] Specifically, the inorganic glue of the present invention selects SiO2 powder (AR≥99.99%, 200 to 800 mesh) as the curing agent, and selects TiH2 (AR≥99.99%, 325 mesh), SiC (AR≥99.99%, 200 to 800 mesh) and graphene experimental-grade powder (average radial size of 40 to 50 um, D50<10 um) as the sintering powder. By adjusting the molar ratio of each substance, the formation of MAX phase Ti3SiC2 is promoted.

[0041] In some alternative embodiments, in step S1, when bonding the surfaces of two silicon carbide base materials to be welded coated with inorganic glue, the bonding pressure is 1 to 5 MPa, the bonding temperature is 50 to 120 °C, and the heat preservation time is 4 to 8 h.

[0042] Specifically, the bonding process is as follows: After the surfaces of two silicon carbide base materials to be welded coated with inorganic glue are fitted to each other, apply a pressure of 1 to 5 MPa to the upper ends of the two fitted silicon carbide base materials to be welded, and place them in a vacuum drying oven. Set the bonding temperature and heat preservation time. By first performing low-temperature curing connection on the silicon carbide base material coated with inorganic glue below 200 °C, the thermal stress can be reduced by 70 to 80%, avoiding microcracks or debonding. At the same time, the inorganic glue can achieve molecular-level densification in this temperature range, thereby forming a nanoscale interlocking structure with the SiC surface.

[0043] In some alternative embodiments, in step S2, when performing spark plasma sintering on the bonded joint, the sintering temperature is 1100 to 1500 °C, the sintering pressure is 10 to 20 MPa, the sintering time is 15 to 30 min, and the heating rate is 100 to 110 °C / min.

[0044] By adopting the spark plasma sintering process, the bonded joint is subjected to spark plasma sintering at 1100 °C to 1500 °C, and at the same time, a corresponding pressure is applied to the bonded joint. During this process, SiO2, TiH2, SiC and graphene are in-situ generated to construct the MAX phase Ti3SiC2 phase, thereby improving the high-temperature shear strength of the joint and being beneficial to its high-temperature service above 1500 °C.

[0045] In some alternative embodiments, the preparation method of the inorganic glue may include the following steps:

[0046] Step 1: Mix SiO2, TiH2, SiC, and graphene uniformly, then add grinding balls and a dispersing solvent for ball milling to obtain a mixed slurry. The mixed slurry is then dried and ground to obtain a composite powder. Specifically, the raw powders can be weighed into a ball mill according to the proportions. Then, grinding balls and a dispersing solvent are added at a ball-to-material ratio of 4:1. The grinding balls can be ZrO2 grinding balls, and the dispersing solvent can be anhydrous ethanol. The amount of dispersing solvent added is sufficient to completely cover the powder and the grinding balls. The ball mill is then placed in a drum ball mill and ball milled at 200 to 400 rpm for 6 to 12 hours to obtain a uniformly mixed slurry. The slurry is then dried in a thermostat at 80 to 100°C. Finally, the mixed powder is ground using an agate grinder and passed through a 100-mesh sieve to obtain a composite powder suitable for bonding and sintering.

[0047] Step 2: Evenly mix the composite powder with an adhesive to obtain an inorganic adhesive. Specifically, the adhesive can be a Na2SiO3 aqueous solution or a sodium aluminosilicate solution, and the molar ratio of the adhesive to the SiO2 in the composite powder is 2:3 to 3:2.

[0048] Another embodiment of the present invention provides a silicon carbide ceramic joint, which is prepared using the above-described method for connecting silicon carbide materials. It should be noted that the silicon carbide ceramic joint of the present invention can be formed by connecting single silicon carbide using the above-described method, or by connecting single silicon carbide and a silicon carbide composite material using the above-described method, or by connecting two silicon carbide composite materials using the above-described method.

[0049] The present invention is described in detail below through specific examples and comparative examples:

[0050] Example 1

[0051] The method for connecting silicon carbide materials in this embodiment includes the following steps:

[0052] Step (1): Preparation of inorganic glue

[0053] Mix SiO2 powder, TiH2 powder, SiC powder and graphene powder evenly by stirring at a molar ratio of 0.5:3:0.5:1.5, and place them in a ball milling tank. Then add ZrO2 grinding balls with diameters of 5 mm, 10 mm, and 15 mm and an appropriate amount of absolute ethanol according to a ball-to-material ratio of 4:1, so that the absolute ethanol completely covers the raw material powder and the grinding balls. Place the ball milling tank in a drum-type ball mill and ball mill for 8 h at a rotation speed of 350 rpm to obtain a mixed slurry. Then place the mixed slurry in an incubator at 80 °C and dry for 24 h to obtain a dried mixed powder. Finally, grind the mixed powder with an agate grinder and pass through a 100-mesh sieve to obtain a composite powder. Pour a 65% aqueous solution of Na2SiO3 into a beaker, place the beaker on a magnetic stirrer, stir it at room temperature, and the stirring speed is 50 rpm. Slowly add the evenly mixed composite powder into the aqueous solution of Na2SiO3 until it is evenly mixed to prepare an inorganic glue. Among them, the molar ratio of Na2SiO3 to SiO2 in the composite powder is 2:3.

[0054] Step (2): Bonding of silicon carbide materials

[0055] Use a diamond grinding disc to polish the surface of the silicon carbide base material to remove surface impurities, oil stains, cutting marks, etc. Then place it in absolute ethanol for ultrasonic cleaning and drying for bonding. Then, the inorganic glue prepared in step (1) is respectively coated on the surfaces of two silicon carbide base materials to be welded through screen printing. Then, the two surfaces of the two silicon carbide base materials coated with the inorganic glue are fitted together and assembled into a structure of base material / inorganic glue / base material as shown in Figure 2 shown, and apply a pressure P, specifically a pressure of 5 MPa, to its upper end. Then place this structure in a vacuum drying oven, set the connection temperature to 100 °C and the heat preservation time to 6 h, and bond the silicon carbide base material in a vacuum environment to obtain a bonded joint.

[0056] Step (3): Spark plasma sintering

[0057] Use high-strength graphite as the sintering die material. During the sintering process, measure the sample temperature with an infrared thermometer. To improve the measurement accuracy, a temperature measurement hole is left in the middle of the graphite outer die. The deeper the temperature measurement hole, the closer the measured temperature is to the actual temperature of the sample, but the deepening of the temperature measurement hole will cause the die strength to decrease. Therefore, in the experiment, the depth of the temperature measurement hole is set to 1 / 2 of the wall thickness of the graphite outer die. After loading the bonded joint into a Φ20 mm inner die, load it into the outer die and compact the upper and lower pressure heads. Then place the bonded joint loaded into the graphite die in a multi-functional sintering furnace for sintering. Adopt a pulsed current mode, and the specific process parameters are as follows: sintering temperature is 1100 °C, sintering pressure is 15 MPa, sintering time is 30 min, heating rate is 100 °C / min, and cool with the furnace after sintering is completed. Finally, obtain a silicon carbide ceramic connection joint.

[0058] Example 2

[0059] The difference between this example and Example 1 is that in the inorganic glue of step (1), the molar ratio of SiO2, TiH2, SiC and graphene is 1:3.5:1:2.

[0060] Example 3

[0061] The difference between this example and Example 1 is that in step (3), the sintering temperature is 1500 °C, the sintering pressure is 20 MPa, and the sintering time is 15 min.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 1 is that referring to the public literature "Preparation and Bonding Properties of High Temperature Resistant Adhesives for SiC Composites", a phosphate hybrid phenolic resin high temperature resistant adhesive PA-PF was prepared with phosphate resin as the matrix, Al2O3 as the curing agent, and ZrO2, Ti and Y2O3 powders as heat resistant fillers by introducing phenolic resin. The SiC ceramic was directly bonded with PA-PF to obtain a SiC ceramic connection joint.

[0064] Comparative Example 2

[0065] The difference between this comparative example and Example 1 is that referring to the public literature "Preparation and Bonding Properties of High Temperature Resistant Adhesives for SiC Composites", a modified silicate high temperature resistant adhesive SA-AN was prepared with Ni2SiO4, Ti, ZrO2 and Si powder modified sodium silicate resin as the matrix and Al and ZnO powder mixture as the curing agent. The SiC ceramic was directly bonded with SA-AN to obtain a SiC ceramic connection joint.

[0066] Comparative Example 3

[0067] The difference between this comparative example and Example 1 is that referring to "Preparation and Properties of Silicate Adhesives for High Temperature Resistant SiC Composites", an adhesive was prepared by designing the proportion of inorganic fillers such as Al2O3, SiO2, LaPO4, etc. and using polyethylene glycol (PEG) for modification.

[0068] The data of the welding rate, room temperature shear strength and high temperature (1500 °C) shear strength of the adhesives in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1. It can be seen from Table 1 that the room temperature shear strength and the shear strength at 1500 °C of the SiC ceramic connection joints in the examples of the present invention are significantly better than those in Comparative Examples 1 to 3. This shows that bonding the SiC material with the inorganic glue of the examples of the present invention and coupling with spark plasma sintering is beneficial to promoting the formation of the three-dimensional MAX phase Ti3SiC2 in the joint, thereby improving the high temperature resistance of the joint.

[0069] Table 1 Room temperature shear strength and high temperature shear strength data of silicon carbide ceramic connection joints in Examples 1 to 3 and Comparative Examples 1 to 3

[0070]

[0071] Although the present invention is disclosed as above, the scope of protection of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will all fall within the scope of protection of the present invention.

Claims

1. A connection method for silicon carbide materials, characterized in that, Including: Applying an inorganic glue onto the surfaces of two silicon carbide base materials to be welded, and bonding the surfaces of the two silicon carbide base materials to which the inorganic glue is applied to obtain a bonded joint; wherein, the inorganic glue comprises the following components: SiO2, TiH2, SiC and graphene; Performing spark plasma sintering on the bonded joint to obtain a silicon carbide ceramic connection joint.

2. The connecting method of the silicon carbide material according to claim 1, wherein In the inorganic glue, the molar ratio of SiO2, TiH2, SiC and graphene is (0.5 to 1):(3 to 3.5):(0.5 to 1):(1.5 to 2).

3. The connecting method of the silicon carbide material according to claim 1, characterized in that, The bonding of the surfaces of the two silicon carbide base materials to which the inorganic glue is applied includes: the bonding pressure is 1 to 5 MPa.

4. The connection method of the silicon carbide material according to claim 1, characterized in that, The bonding of the surfaces of the two silicon carbide base materials to which the inorganic glue is applied includes: the bonding temperature is 50 to 120 °C, and the heat preservation time is 4 to 8 h.

5. The connection method of the silicon carbide material according to claim 1, characterized in that, The spark plasma sintering of the bonded joint includes: the sintering temperature is 1100 to 1500 °C, the sintering pressure is 10 to 20 MPa, and the sintering time is 15 to 30 min.

6. The connecting method of the silicon carbide material according to claim 5, characterized in that, The heating rate of the spark plasma sintering is 100 to 110 °C / min.

7. The connection method of the silicon carbide material according to claim 1, characterized in that, The preparation method of the inorganic glue includes: Mixing SiO2, TiH2, SiC and graphene evenly, and simultaneously adding grinding balls and a dispersion solvent for ball milling to obtain a mixed slurry, and drying and grinding the mixed slurry to obtain a composite powder; Mixing the composite powder and an adhesive evenly to obtain the inorganic glue.

8. The connection method of the silicon carbide material according to claim 7, wherein, The adhesive is an aqueous solution of Na2SiO3 or a sodium aluminosilicate solution.

9. The joining method of the silicon carbide material according to claim 7, wherein The molar ratio of SiO2 in the composite powder to the adhesive is 2:3 to 3:

2.

10. A silicon carbide ceramic connection joint, characterized in that, The silicon carbide ceramic connection joint is prepared by using the connection method of the silicon carbide material according to any one of claims 1 to 9.

Images