A method for assembling ceramic matrix composite and metal with improved connection hole precision

Abstract

This invention discloses a method for assembling ceramic-based composites and metal to improve the accuracy of connecting holes. The method includes steps S1, assembling the composite component; S2, placing the assembled composite component in a CVI deposition furnace to deposit a SiC substrate; S3, placing the composite component with the deposited SiC substrate on a CNC milling machine and machining positioning holes on the composite component that match the solid cylindrical pins of the metal part; S4, placing the composite component in a CVI deposition furnace and depositing a silicon carbide protective coating on the surface; S5, using the solid cylindrical pins on the metal part to position and test-fit the positioning holes on the composite component, and applying adhesive to the mating surfaces; S6, machining the connecting holes; and S7, surface cleaning. In this invention, the solid cylindrical pins are embedded in the positioning holes, achieving rapid positioning of the composite component and the metal part. The assembly is simple, and if dimensional deviations occur, only the metal part needs to be replaced. The product has high maintainability and a short maintenance cycle.

Description

Technical Field

[0001] This invention relates to the field of composite material assembly technology, and more specifically to an assembly method for ceramic-based composite materials and metals that improves the accuracy of connecting holes. Background Technology

[0002] Currently, during the high-temperature chemical vapor deposition (CVD) process of ceramic matrix composites, stress release occurs, resulting in micro-deformation and thermal warping of the components. Furthermore, the formation of ceramic products on the surface of the composite during CVD causes dimensional deviations, making it difficult to fabricate precision and complex product components as a whole. To shorten product development cycles and improve product quality, the current approach often adopts a design scheme that combines ceramic matrix composites with metals. Ceramic matrix composites provide a lightweight skeleton with high temperature resistance, low density, high specific strength, high specific modulus, and oxidation resistance, while metal components ensure product precision.

[0003] Chinese invention patent No. ZL202011472045.0 proposes a method for assembling a metal reinforcing component with a ceramic-based composite support. The metal component mainly serves as a reinforcement, and the metal reinforcing component has pre-drilled connecting holes (hollow cylindrical pins) before assembly. The precision requirement of the connecting hole of a single metal part is low, and there are still assembly errors and assembly errors caused by deformation of the composite components during the subsequent assembly process with the composite material. It cannot meet the overall precision requirements of multiple ultra-high precision connecting holes.

[0004] In existing methods, the connection hole structure between ceramic matrix composites and metal parts is mostly that the flat metal parts and ceramic matrix composites are bonded together with adhesive. After chemical vapor deposition preparation, deviations in the surface of the ceramic matrix composite and the diameter and position of the composite holes can lead to deviations in the installation position of the metal parts. This often requires repeated disassembly and reassembly to adjust the position of the metal parts, resulting in large errors in the overall assembly accuracy of the product. Furthermore, since the metal parts and ceramic matrix composites are mostly bonded together with adhesive, the metal parts are prone to peeling off. This restricts the development of ceramic matrix composite components to higher dimensional accuracy, making it difficult to meet the market demand for high-precision products in fields such as deep space aerospace. The quality stability is poor and the production cycle is long.

[0005] Therefore, it is crucial to adopt certain measures and new methods to further improve and optimize the connection structure between ceramic matrix composites and metal parts, and to enhance the accuracy of the connection holes. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention provides an assembly method for ceramic matrix composites and metals that improves the accuracy of connecting holes. This method solves the problems of hole deformation in ceramic matrix composites during vapor deposition, high difficulty in rework when connecting holes with metal parts, and low assembly accuracy.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] On the one hand, a method for assembling ceramic-based composites and metals to improve the accuracy of connecting holes is provided, which includes the following steps:

[0009] Step S1: Assemble composite components by assembling the various parts and components into composite components.

[0010] Step S2: Composite component substrate deposition. The assembled composite component is placed in a CVI deposition furnace, and a SiC substrate is deposited on the surface of the composite component.

[0011] Step S3: Hole making of composite component. After the SiC substrate deposition is completed, the composite component is placed on a CNC milling machine. Positioning holes that match the solid cylindrical pins on the metal parts are machined on the composite component, and there is a gap between the hole wall of the positioning hole on the composite component and the solid cylindrical pin.

[0012] Step S4: Surface protective deposition of composite components. The composite component with completed hole making is placed in a CVI deposition furnace, and a surface silicon carbide protective coating is deposited on the surface of the composite component.

[0013] Step S5: The composite component and the metal part are bonded and assembled. The solid cylindrical pin on the metal part is used to position and test fit with the positioning hole on the composite component. The mating surfaces between the metal part and the positioning hole are bonded with adhesive.

[0014] Step S6: Machining connecting holes. Place the glued composite component and the metal part together on a CNC milling machine. Machining connecting holes on the metal plate of the metal part. The connecting holes pass through the solid cylindrical pin on the lower surface of the metal plate.

[0015] Step S7: External cleaning. Use a lint-free cloth dampened with alcohol to clean the exterior of the composite components and metal parts, as well as the inner walls of the connecting holes, to remove any excess material.

[0016] In this invention, a solid cylindrical pin on a metal part is embedded into a positioning hole on a composite component. The position of the solid cylindrical pin is consistent with the position of the final connection hole on the metal part. The solid cylindrical pin enables rapid positioning of the ceramic-based composite and the metal part, which is easy to assemble and the metal part has a robust structure that is not prone to falling off. The product accuracy is entirely guaranteed by the metal part. If the dimensions are out of tolerance, only the metal part needs to be replaced. The product has strong maintainability and a short maintenance cycle.

[0017] Furthermore, the specific process parameters for depositing the SiC substrate on the surface of the composite component in step S2 are as follows: the deposition temperature is 1000~1050℃, the vacuum degree is less than 1000Pa; argon gas at a flow rate of 0.3L / min~0.4L / min is used as the reaction protective gas, and H2 at a flow rate of 0.4~0.5L / min is used as the carrier gas. Trichloromethylsilane is fed into the CVI deposition furnace to react with H2, and the deposition time is 45~50h.

[0018] Furthermore, in step S3, the gap between the hole wall of the positioning hole on the composite component and the solid cylindrical pin is 0.2mm ~ 0.3mm.

[0019] Furthermore, in step S3, the cutting tool of the CNC milling machine is a glass drill with an electroplated diamond coating, and the diamond coating has a particle size of 120~160 mesh.

[0020] Furthermore, the specific process parameters for depositing a surface silicon carbide protective coating on the surface of the composite component in step S4 are as follows: the deposition temperature is 950~1000℃, the vacuum degree is less than 1000Pa; argon gas at a flow rate of 0.2L / min~0.3L / min is used as the reaction protective gas, and H2 at a flow rate of 0.1~0.2L / min is used as the carrier gas. Trichloromethylsilane is fed into the deposition furnace to react with H2, and the deposition time is 30~35h.

[0021] Furthermore, the machining process of the connecting holes in step S6 includes roughing and finishing. After roughing, the center position coordinates of each connecting hole are checked on a CNC milling machine using a lever dial indicator. The center position coordinates of the connecting holes are compared with the theoretical hole position coordinates to verify and adjust the center position coordinates of the connecting holes until they are consistent with the theoretical hole position coordinates. Then, the connecting holes are finished to the required values.

[0022] Furthermore, the specific process requirements for machining the connecting hole in step S6 are as follows: the connecting hole is machined using climb milling, and the depth of cut of the CNC milling machine tool is 0.1~0.15mm;

[0023] The cooling method for the connecting hole is as follows: water is sprayed into the connecting hole, and compressed air is used to clean the chips from the cutting edge of the tool.

[0024] On the other hand, a connection structure for assembling ceramic-based composite materials and metal to improve the accuracy of connection holes includes a composite material component and a metal part. The composite material component has a positioning hole. The metal part includes a metal plate and a solid cylindrical pin disposed in the middle of the lower surface of the metal plate. The solid cylindrical pin is embedded in the positioning hole and the mating surface between the solid cylindrical pin and the positioning hole is bonded by applying an adhesive. The metal plate has a connection hole that passes through the solid cylindrical pin and the positioning hole.

[0025] Furthermore, the diameter of the solid cylindrical pin is 2 mm to 3 mm larger than the diameter of the connecting hole, and the diameter of the positioning hole is 2 mm to 3 mm larger than the diameter of the solid cylindrical pin.

[0026] Furthermore, the shape of the metal plate matches the composite component and is no larger than the connection part on the composite component.

[0027] This invention discloses an assembly method for ceramic-based composites and metals that improves the accuracy of connecting holes, and its beneficial effects are as follows:

[0028] 1. In this invention, a solid cylindrical pin on the metal part is embedded into a positioning hole on the composite component. The position of the solid cylindrical pin is consistent with the position of the final connection hole on the metal part. The solid cylindrical pin is used to achieve rapid positioning of the ceramic-based composite and the metal part. The assembly difficulty is low, and the metal part has a reliable structure and is not easy to fall off. The product accuracy is entirely guaranteed by the metal part. If the size is out of tolerance, only the metal part needs to be replaced. The product has strong maintainability and short maintenance cycle.

[0029] 2. After the metal parts and ceramic matrix composite components in this invention are assembled, the connection holes are only machined at the solid cylindrical pins of the metal parts to ensure the precision requirements of the final product. This avoids the need to machine both the connection holes on the flat metal parts and the ultra-hard ceramic matrix composite components with silicon carbide as the matrix, which are required in the prior art. This results in less tool wear and higher machining accuracy.

[0030] 3. In this invention, there is a gap between the positioning hole on the composite component and the solid cylindrical pin on the metal part. Therefore, it is only necessary to process the positioning hole on the composite component that matches the solid cylindrical pin on the metal part before assembly. The requirements for the preparation accuracy of the composite component before assembly are low, which can greatly improve the product assembly progress.

[0031] 4. In this invention, there is a gap between the positioning hole on the composite component and the solid cylindrical pin on the metal part. This gap facilitates the overflow and filling of adhesive between the bonding surface of the metal part and the bonding surface of the composite component. This gap can also be used as a thermal expansion gap for the metal part to prevent the metal part from being damaged by heat to the holes of the composite component or the whole product. Attached Figure Description

[0032] Figure 1 This is a schematic diagram illustrating the steps of an assembly method for ceramic-based composite materials and metals to improve the accuracy of connecting holes according to the present invention.

[0033] Figure 2 This is a schematic diagram of the steps for processing the connecting hole according to the present invention.

[0034] Figure 3 This is a schematic diagram of the connection structure of an assembly method for ceramic matrix composites and metals according to the present invention.

[0035] Figure 4 This is a schematic diagram of the structure of the metal part of the present invention.

[0036] Figure 5 This is a structural schematic diagram of the composite material component of the present invention.

[0037] Among them, 1. composite components; 2. metal parts; 3. metal plates; 4. solid cylindrical pins; 5. positioning holes; 6. connecting holes; 7. adhesives. Detailed Implementation

[0038] The present invention is described in detail with reference to specific embodiments to enable those skilled in the art to understand the invention. However, it should be understood that the invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0039] Example 1

[0040] refer to Figure 1 This embodiment illustrates the steps of an assembly method for ceramic matrix composites and metals to improve the accuracy of connecting holes. The purpose is to solve the problems of hole deformation in ceramic matrix composites during vapor deposition, and the difficulty of rework and low assembly accuracy when connecting holes with metal parts. The assembly method in this embodiment will be described in detail below.

[0041] A method for assembling ceramic-based composites and metals to improve the accuracy of connecting holes includes the following steps:

[0042] Step S1: Assemble composite component 1 by assembling the various parts and components into composite component 1.

[0043] Step S2: Substrate deposition of composite component 1. The assembled composite component 1 is placed in a CVI deposition furnace, and SiC substrate is deposited on the surface of the composite component 1.

[0044] Specifically, the specific process parameters for depositing the SiC substrate on the surface of the composite component 1 in step S2 are: deposition temperature of 1000~1050℃ and vacuum degree of less than 1000Pa.

[0045] Argon gas at a flow rate of 0.3 L / min to 0.4 L / min was used as the protective gas for the reaction, and H2 at a flow rate of 0.4 L / min was used as the carrier gas. Trichloromethylsilane was fed into the CVI deposition furnace to react with H2, and the deposition time was 45 to 50 h.

[0046] In this embodiment, after the parameters of the CVI deposition furnace are set, the assembled composite component 1 is placed in the CVI deposition furnace, and the CVI deposition furnace is started. The deposition temperature of the CVI deposition furnace is 1050°C, the vacuum degree is 1000Pa, argon gas at a flow rate of 0.4L / min is used as the reaction protective gas, and H2 at a flow rate of 0.5L / min is used as the carrier gas.

[0047] Trichloromethylsilane is fed into a CVI deposition furnace to react with H2 for 50 hours, thereby depositing a SiC matrix on the surface of the composite component 1. This enables the composite component 1 to meet the requirements for use under ultra-high temperature and long life conditions, and allows the composite component 1 to resist high temperature stress environment for a long time.

[0048] Step S3: Hole making of composite component 1. After the SiC substrate deposition is completed, the composite component 1 is placed on a CNC milling machine. Positioning holes 5 that match the solid cylindrical pins 4 on the metal part 2 are machined on the composite component 1, and there is a gap between the hole wall of the positioning hole 5 on the composite component 1 and the solid cylindrical pins 4.

[0049] Specifically, in step S3, the gap between the hole wall of the positioning hole 5 and the solid cylindrical pin 4 on the composite component 1 after SiC substrate deposition is 0.2 mm ~ 0.3 mm. In step S3, the cutting tool of the CNC milling machine is a glass drill with an electroplated diamond coating, and the particle size of the diamond coating is 120~160 mesh.

[0050] In this embodiment, the solid cylindrical pin 4 can also be a triangular prism or a multi-faceted prism, which is more conducive to the angular positioning of the metal part 2 and the composite component 1 during the assembly process, thereby improving assembly efficiency and assembly quality.

[0051] The cutting tool of the CNC milling machine used to process ceramic matrix composite component 1 is: electroplated diamond-coated glass drill; the diamond coating particle size is: 140±20 mesh.

[0052] Furthermore, the diameter of the positioning hole 5 prepared by the tool on the CNC milling machine is 2 mm to 3 mm larger than the diameter of the solid cylindrical pin 4, thereby ensuring that the gap between the hole wall of the positioning hole 5 and the solid cylindrical pin 4 is 0.2 mm to 0.3 mm.

[0053] Therefore, only the positioning hole 5 matching the solid cylindrical pin 4 of the metal part 2 needs to be machined on the composite component 1 before assembly. The preparation accuracy requirements of the composite component 1 before assembly are low, which can greatly improve the product assembly progress. Moreover, the hole gap between the solid cylindrical pin 4 and the positioning hole 5 on the composite component 1 facilitates the overflow and filling of adhesive on the bonding surface between the metal plate 3 on the metal part 2 and the composite component 1. The hole gap between the solid cylindrical pin 4 and the positioning hole 5 on the composite component 1 can also serve as a thermal expansion gap for the metal part 2, preventing the positioning hole 5 on the composite component 1 or the entire product from being damaged by heat.

[0054] Step S4: Surface protective deposition of composite component 1. The composite component 1 with completed hole making is placed in a CVI deposition furnace, and a surface silicon carbide protective coating is deposited on the surface of the composite component 1.

[0055] Specifically, the specific process parameters for depositing a surface silicon carbide protective coating on the surface of the composite component 1 in step S4 are: deposition temperature of 950~1000℃ and vacuum degree of less than 1000Pa.

[0056] Argon gas at a flow rate of 0.2 L / min to 0.3 L / min was used as the protective gas for the reaction, and H2 at a flow rate of 0.1 L / min was used as the carrier gas. Trichloromethylsilane was fed into the deposition furnace to react with H2, and the deposition time was 30 to 35 h.

[0057] In this embodiment, the composite component 1 with the holes made is placed in a CVI deposition furnace, and a silicon carbide protective coating is deposited on the surface of the composite to prevent the fiber bundles from oxidizing in a high-temperature environment.

[0058] After setting the parameters of the CVI deposition furnace, place the composite component 1 with the positioning hole 5 prepared inside the CVI deposition furnace, start the CVI deposition furnace, the deposition temperature of the CVI deposition furnace is 950℃, the vacuum degree is 1000Pa, argon gas at 0.2L / min is used as the reaction protective gas, and H2 at a flow rate of 0.2L / min is used as the carrier gas.

[0059] Trichloromethylsilane was fed into a CVI deposition furnace to react with H2 for 35 hours, thereby depositing a surface silicon carbide protective coating on the surface of the composite component 1.

[0060] Step S5: The composite component 1 and the metal part 2 are bonded and assembled. The solid cylindrical pin 4 on the metal part 2 is used to position and test fit with the positioning hole 5 on the composite component 1. The mating surfaces between the metal part 2 and the positioning hole 5 are bonded with adhesive 7.

[0061] In this embodiment, the adhesive used for bonding is a common resin-curing adhesive. Other types of adhesives may also be selected depending on the service temperature conditions of the product.

[0062] After the protective deposition of the silicon carbide protective coating on the surface of the composite component 1 is completed, the solid cylindrical pin 4 in the middle of the lower surface of the metal plate 3 on the metal part 2 is inserted into the positioning hole 5 on the composite component 1. The mating surfaces between the metal part 2, the solid cylindrical pin 4, the composite component 1 and the positioning hole 5 are bonded together by applying resin curing adhesive. During the assembly process, it is ensured that there is a gap between the hole wall of the positioning hole 5 and the solid cylindrical pin 4. The gap can serve as a thermal expansion gap for the metal part 2 to prevent damage to the composite component 1, and can also serve as an overflow channel for the resin curing adhesive to improve the adhesive strength.

[0063] Step S6: Machining the connecting hole 6. Place the composite component 1 and the metal part 2 together on a CNC milling machine after the adhesive is completed. Machining the connecting hole 6 on the metal plate 3 of the metal part 2. The connecting hole 6 passes through the solid cylindrical pin 4 on the lower surface of the metal plate 3.

[0064] Specifically, the machining process of the connecting hole 6 in step S6 includes roughing and finishing;

[0065] After rough machining, the center position coordinates of each connecting hole 6 are checked on a CNC milling machine using a lever dial indicator. The center position coordinates of the connecting hole 6 are compared with the theoretical hole position coordinates to verify and adjust the center position coordinates of the connecting hole 6 until they match the theoretical hole position coordinates. Then, the connecting hole 6 is finished to the required value.

[0066] Specifically, the specific process requirements for machining the connecting hole 6 in step S6 are as follows:

[0067] The connecting hole 6 is drilled using climb milling, and the depth of cut of the CNC milling machine tool is 0.1~0.15mm;

[0068] The cooling method for drilling the connecting hole 6 is as follows: clean water is sprayed into the hole of the connecting hole 6, and the cutting edge of the tool is cleaned of chips by compressed air to prevent the chips from scratching the hole wall.

[0069] In this embodiment, the composite component 1 and the metal part 2 after adhesive bonding are placed together on a CNC milling machine and clamped securely. A connecting hole 6 is machined on the metal plate 3 of the metal part 2. The connecting hole 6 passes through the solid cylindrical pin 4 on the lower surface of the metal plate 3.

[0070] The processing procedure is as follows:

[0071] Step S61: Rough machining. During rough machining, first use a center drill to determine the position of the connecting hole 6, then use an alloy drill bit to make the connecting hole 6, and finally use an alloy end mill to ensure that the dimensional accuracy of the connecting hole 6 is ±0.05mm.

[0072] Step S62: Self-inspection. With the flange product clamped in its original position, use a lever dial indicator to self-inspect the coordinate value of the center position of the connecting hole 6 and verify it with the theoretical hole position coordinate value of the connecting hole 6 in the CNC program. After verifying and adjusting the measured coordinate value of the center position of the connecting hole 6 to match the theoretical hole position coordinate value, proceed to the next step of finishing.

[0073] Step S63: Finishing. The carbide end mill adopts climb milling cutting method. The depth of cut of the carbide end mill is 0.1~0.15mm. At the same time, the cutting area is cooled by spraying clean water, and the cutting edge is cleaned with compressed air in time to prevent the chips from scratching the hole wall, thereby forming a high-precision connecting hole 6.

[0074] Step S7: External cleaning. Use a lint-free cloth dampened with alcohol to clean the exterior of the composite component 1 and the metal part 2, as well as the inner wall of the connecting hole 6, to remove any excess material.

[0075] Example 2

[0076] refer to Figure 2 This embodiment presents a schematic diagram of a connection structure applied to an assembly method of ceramic matrix composites and metals. Its purpose is to solve the problems of pore deformation in ceramic matrix composites during vapor deposition, and the difficulty of rework and low assembly accuracy when connecting with pores in metal parts. The connection structure in this embodiment will be described in detail below.

[0077] A ceramic-based composite and metal connection structure for improving the accuracy of connection holes includes a composite component 1 and a metal component 2. The composite component 1 has a positioning hole 5. The metal component 2 includes a metal plate 3 and a solid cylindrical pin 4 disposed in the middle of the lower surface of the metal plate 3.

[0078] Specifically, the solid cylindrical pin 4 is embedded in the positioning hole 5 and the mating surfaces between the solid cylindrical pin 4 and the positioning hole 5 are bonded together by applying adhesive 7. The metal plate 2 has a connecting hole 6 that passes through the solid cylindrical pin 4 and the positioning hole 5.

[0079] In this embodiment, the composite component 1 is composed of multilayer ceramic matrix composite parts. After the assembly and deposition of each component, positioning holes 5 are prepared on the composite component 1. The metal part 2 includes a metal plate 3 and a solid cylindrical pin 4. The metal plate 3 has a flat plate structure. The solid cylindrical pin 4 is fixedly set in the middle of the lower surface of the metal plate 3 and is embedded in the positioning hole 5 opened on the composite component 1. The connection hole 6 is then machined in one overall clamping process using a CNC machining equipment.

[0080] This method ensures that the metal part 2 can be quickly installed into the composite component 1, improving assembly and positioning efficiency. It also reduces the machining accuracy requirements of the positioning holes 5 on the composite component 1, improving the machining efficiency of the composite component 1. The metal part 2 and the composite component 1 are connected by adhesive bonding. Compared with screwing or riveting, the working intensity is low and the operation is simple.

[0081] Specifically, the diameter of the solid cylindrical pin 4 is 2 mm to 3 mm larger than the diameter of the connecting hole 6, the diameter of the positioning hole 5 is 2 mm to 3 mm larger than the diameter of the solid cylindrical pin 4, and the shape of the metal plate 2 matches the composite component 1 and is not larger than the connecting part on the composite component 1.

[0082] In this embodiment, the diameter of the solid cylindrical pin 4 is 2 mm to 3 mm larger than the diameter of the connecting hole 6, which makes it easier to prepare the connecting hole 6 on the solid cylindrical pin 4. This reduces the positional accuracy requirement of the positioning hole 5 on the composite component 1, i.e., the hole diameter size requirement. It solves the problem of large assembly error and poor positional accuracy of the connecting hole 6 in the assembly with hollow cylindrical pins. It is easy to ensure the processing of the connecting hole 6 while taking into account the weight control of the product and saving material costs.

[0083] The diameter of the positioning hole 5 is 2 mm to 3 mm larger than the diameter of the solid cylindrical pin 4, ensuring the gap between the hole wall of the positioning hole 5 and the solid cylindrical pin 4. This gap can serve as a thermal expansion gap for the metal part 2, preventing damage to the composite component 1, and can also serve as an overflow channel for the resin curing adhesive, improving the adhesive's adhesion. The metal part 2 and the composite component 1 are bonded together by the adhesive layer. Compared with screwing or riveting, this method has lower working intensity and is easier to operate.

[0084] It can also ensure that the solid cylindrical pin 4 on the metal part 2 can be quickly installed into the positioning hole 5 on the composite component 1, thereby improving the assembly positioning efficiency and reducing the machining accuracy requirements of the positioning hole 5 on the composite component 1, thus improving the machining efficiency of the composite component 1.

[0085] Furthermore, the length of the solid cylindrical pin 4 on the metal part 2 is less than the depth of the positioning hole 5 on the composite component 1, which makes it easy for the metal part 2 to avoid interference with other parts on the surface of the composite component 1, and can also serve as a thermal expansion gap for the metal part 2, preventing the metal part 2 from being damaged by axial expansion due to heat.

[0086] Although specific embodiments of the invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by a person skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of this patent.

Claims

1. A method for assembling ceramic-based composites and metals to improve the accuracy of connecting holes, characterized in that, Includes the following steps: Step S1: Assemble composite component (1); Assemble each component into composite component (1). Step S2, substrate deposition of composite component (1): The assembled composite component (1) is placed in a CVI deposition furnace, and a SiC substrate is deposited on the surface of the composite component (1). Step S3: Hole making of composite component (1); After the SiC substrate deposition is completed, the composite component (1) is placed on a CNC milling machine, and positioning holes (5) that match the solid cylindrical pin (4) on the metal part (2) are machined on the composite component (1), and there is a gap between the hole wall of the positioning hole (5) on the composite component (1) and the solid cylindrical pin (4). Step S4: Surface protection deposition of composite component (1); The composite component (1) with completed hole making is placed in a CVI deposition furnace, and a surface silicon carbide protective coating is deposited on the surface of the composite component (1); Step S5: The composite component (1) and the metal part (2) are bonded and assembled; the solid cylindrical pin (4) on the metal part (2) is positioned and tested with the positioning hole (5) on the composite component (1), and the mating surfaces between the metal part (2) and the positioning hole (5) are bonded with adhesive (7). Step S6: Machining the connecting hole (6); Place the composite component (1) and the metal part (2) together on a CNC milling machine after gluing, and machine the connecting hole (6) on the metal plate (3) of the metal part (2). The connecting hole (6) passes through the solid cylindrical pin (4) on the lower surface of the metal plate (3). Step S7, External cleaning: Use a lint-free cloth soaked in alcohol to clean the exterior of the composite component (1) and the metal part (2), as well as the inner wall of the connecting hole (6), of any excess material.

2. The method for assembling ceramic-based composite materials and metals to improve the accuracy of connecting holes according to claim 1, characterized in that, The specific process parameters for depositing the SiC substrate on the surface of the composite component (1) in step S2 are: deposition temperature of 1000~1050℃ and vacuum degree of less than 1000Pa. Argon gas at a flow rate of 0.3 L / min to 0.4 L / min was used as the protective gas for the reaction, and H2 at a flow rate of 0.4 L / min was used as the carrier gas. Trichloromethylsilane was fed into the CVI deposition furnace to react with H2, and the deposition time was 45 to 50 h.

3. The method for assembling ceramic-based composite materials and metals to improve the accuracy of connecting holes according to claim 1, characterized in that, In step S3, the gap between the hole wall of the positioning hole (5) on the composite component (1) and the solid cylindrical pin (4) is 0.2 mm to 0.3 mm.

4. The assembly method of ceramic matrix composite and metal for improving the accuracy of connecting holes according to claim 1, characterized in that: In step S3, the cutting tool of the CNC milling machine is a glass drill with an electroplated diamond coating, and the diamond coating has a particle size of 120~160 mesh.

5. The method for assembling ceramic-based composite materials and metals to improve the accuracy of connecting holes according to claim 1, characterized in that, The specific process parameters for depositing a surface silicon carbide protective coating on the surface of the composite component (1) in step S4 are: deposition temperature 950~1000℃, vacuum degree less than 1000Pa. Argon gas at a flow rate of 0.2 L / min to 0.3 L / min was used as the protective gas for the reaction, and H2 at a flow rate of 0.1 L / min was used as the carrier gas. Trichloromethylsilane was fed into the deposition furnace to react with H2, and the deposition time was 30 to 35 h.

6. The method for assembling ceramic-based composites and metals to improve the accuracy of connecting holes according to claim 5, characterized in that: The machining process of the connecting hole (6) in step S6 includes roughing and finishing; After rough machining, the center position coordinates of each connecting hole (6) are checked by lever dial indicator on CNC milling machine. The center position coordinates of the connecting hole (6) are compared with the theoretical hole position coordinates of the connecting hole (6) to check and adjust the center position coordinates of the connecting hole (6) until they are consistent with the theoretical hole position coordinates of the connecting hole (6). Then, the connecting hole (6) is finished to the required value.

7. The method for assembling ceramic matrix composites and metals to improve the accuracy of connecting holes according to claim 6, characterized in that: The specific process requirements for machining the connecting hole (6) in step S6 are as follows: The connecting hole (6) is drilled using climb milling, and the depth of cut of the CNC milling machine tool is 0.1~0.15mm; The cooling method for the connection hole (6) is as follows: water is sprayed into the hole of the connection hole (6), and the cutting edge is cleaned with compressed air.

8. A connection structure made using the assembly method of ceramic matrix composite and metal according to any one of claims 1-7 for improving the accuracy of connection holes, characterized in that: It includes a composite material component (1) and a metal part (2); the composite material component (1) has a positioning hole (5); the metal part (2) includes a metal plate (3) and a solid cylindrical pin (4) disposed in the middle of the lower surface of the metal plate (3); the solid cylindrical pin (4) is embedded in the positioning hole (5) and the mating surface between the solid cylindrical pin (4) and the positioning hole (5) is bonded by applying adhesive (7); The metal plate (3) has a connecting hole (6) through which a solid cylindrical pin (4) and a positioning hole (5) pass.

9. The connection structure according to claim 8, characterized in that: The diameter of the solid cylindrical pin (4) is 2 mm to 3 mm larger than the diameter of the connecting hole (6); The diameter of the positioning hole (5) is 2 mm to 3 mm larger than the diameter of the solid cylindrical pin (4).

10. The connection structure according to claim 8, characterized in that: The shape of the metal plate (3) matches the composite component (1) and is not larger than the connection part on the composite component (1).

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