Preparation method of fiber-reinforced ceramic-based / carbon-based composite material honeycomb structure

Abstract

The invention discloses a preparation method of a fiber-reinforced ceramic-based / carbon-based composite material honeycomb structure, and belongs to the field of preparation of ceramic-based / carbon-based composite material honeycomb structures. According to the invention, a unique path is formed through a wiring method to lay the fiber bundles, so that the integrated molding preparation of the honeycomb structure of the fiber-reinforced ceramic-based / carbon-based composite material is realized, and the thickness consistency of the honeycomb structure is ensured. The contact wall surfaces of different units of the honeycomb structure form the same common wall surface through a routing method, so that the overall stability of the honeycomb structure is remarkably improved. The laying path and density of the fiber bundles are accurately controlled around the three-edged positioning column through a routing method, the unit size precision of the honeycomb structure is improved, and the consistency of the honeycomb structure units is ensured. The laid fiber bundles are pressed and shaped through a tablet press, overall densification forming treatment is carried out through a chemical vapor deposition (CVI) process, and the strength and the high-temperature resistance of the honeycomb structure of the ceramic-based / carbon-based composite material are improved. The invention has the advantages of integration, high strength, stable structure and high preparation precision.

Description

Technical Field

[0001] The invention relates to a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure, belonging to the technical field of preparing ceramic-based / carbon-based composite honeycomb structures. Background Art

[0002] Standing at the forefront of the 21st century, hypersonic vehicles, as an important carrier of space technology, can significantly improve human ability to enter, control and utilize space, and play a nearly decisive role in the development and game of near-space resources. As key components of hypersonic vehicles, thermal protection materials and structures such as nose cones, leading edges / wing leading edges, scramjet engine combustion chambers, and rocket engine nozzles / throat liners play a pivotal role and have become the safety cornerstone for the development of hypersonic vehicles.

[0003] As the flight speed and altitude change, the aerodynamic / thermal load conditions of hypersonic aircraft are constantly changing, and the requirements for the design and manufacture of lightweight, heat-insulating and load-bearing integrated thermal protection structures are gradually increasing. The higher the flight speed and the longer the time in the atmosphere, the more stringent the requirements are. Typical working environment characteristics such as "high temperature, long time, oxygen, and complex thermal / mechanical loads" have made hypersonic aircraft pose urgent needs and severe challenges to the lightweight thermal protection structure.

[0004] Ceramic-based / carbon-based composite materials have extremely high melting points and excellent anti-oxidation and anti-ablation properties. They can be used for a long time in an oxidizing environment above ultra-high temperature and maintain non-ablation and structural integrity. They are a type of ultra-high temperature non-ablative heat protection material with great application prospects. They are important or primary candidate materials for key thermal structures such as nose cones and leading edges of hypersonic vehicles. Ceramic-based / carbon-based composite honeycomb structures have the characteristics of low density, high strength, high modulus, low expansion coefficient, high temperature resistance, thermal shock resistance, ablation resistance and excellent high-temperature mechanical properties. They are widely used in the aerospace field. Therefore, the preparation of ceramic-based / carbon-based composite honeycomb structures has become a research hotspot in the field of hypersonic vehicle thermal protection materials and structures.

[0005] Common preparation processes for ceramic-based / carbon-based composite materials include RMI, CVI, PIP, etc. The RMI process is prone to damage the fiber, which affects the performance of the material; the CVI process can be used to prepare ceramic-based / carbon-based composite materials at a lower temperature, with less damage to the fiber, and the integrity of the component structure can be maintained during the preparation process. As long as the wall is not too thick, the net size molding preparation of complex-shaped products can be achieved; the PIP process has the disadvantages of high material porosity and a long preparation cycle.

[0006] The preparation of existing fiber-reinforced ceramic-based / carbon-based composite honeycomb structures has the following technical difficulties: (1) Insufficient interface bonding strength: Traditional fiber-reinforced ceramic-based / carbon-based composite honeycomb structures use an adhesive process to bond each unit together. Under high loads, interface peeling is prone to occur, resulting in insufficient overall stability of the structure; (2) Difficulty in controlling unit dimensional accuracy and poor thickness consistency: In a honeycomb structure, the dimensional accuracy and thickness consistency of each unit have a direct impact on the performance of the entire structure, and it is difficult to achieve high precision and thickness consistency; (3) During heat treatment and sintering, thermal stress and thermal deformation cause structural damage, and material properties are affected; (4) As the honeycomb structure extends in length and width, the preparation cost and cumulative error will continue to increase. Due to the lack of auxiliary assembly molds, the assembly positioning accuracy of each unit of the traditional array honeycomb structure is difficult to guarantee, and the assembly effect does not meet existing needs, which is not conducive to large-scale production.

[0007] In summary, the fiber-reinforced ceramic-based / carbon-based composite honeycomb structures made by various existing preparation processes have insufficient interface bonding strength, and it is difficult to ensure the unit size accuracy and thickness consistency. The structure is easily damaged during the sintering process, and it is difficult to mass-produce array honeycomb structures. There is a loss in material properties, which to a certain extent limits the wide application and development of fiber-reinforced ceramic-based / carbon-based composite honeycomb structures in the field of hypersonic aircraft thermal protection technology. Therefore, the preparation process and interface bonding method of fiber-reinforced ceramic-based / carbon-based composite honeycomb structures are studied, and a simple, fast, high-precision, and consistent thickness preparation process and a stable, high-strength interface bonding method are proposed, which are of great significance to the development of fiber-reinforced ceramic-based / carbon-based composite honeycomb structures. Summary of the invention

[0008] In order to solve the technical problems of insufficient interface bonding strength of existing fiber reinforced ceramic-based / carbon-based composite honeycomb structures, difficulty in ensuring unit size accuracy and thickness consistency, easy structural damage during sintering, and difficulty in large-scale production, and to improve the comprehensive performance of fiber reinforced ceramic-based / carbon-based composite honeycomb structures, the present invention provides a method for preparing a fiber reinforced ceramic-based / carbon-based composite honeycomb structure.

[0009] The purpose of the present invention is achieved through the following technical solutions.

[0010] The present invention discloses a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure, comprising the following steps:

[0011] S1. According to the designed size and position of the honeycomb structure, a positioning plate and a triangular positioning column are prepared, and a triangular through hole is processed at the corresponding position of the positioning plate;

[0012] S2. According to the number of units of the honeycomb structure, insert the triangular positioning column into the triangular through hole of the positioning plate and press it tightly;

[0013] S3. According to the designed size and thickness of the honeycomb structure, a fiber bundle with a suitable diameter is selected, and the first layer of fiber bundles is laid around the triangular positioning column by the wiring method;

[0014] 3.1. Lay transverse fiber bundles along the upper and lower edges of the first, second and third rows of honeycomb structure units respectively;

[0015] 3.2. Lay longitudinal fiber bundles along the left and right edges of the first and third rows of honeycomb structure units, respectively;

[0016] 3.3. Lay the longitudinal fiber bundle along the right edge of the fourth row of honeycomb structure units;

[0017] S4. According to the designed height of the honeycomb structure, based on the laid first layer of fiber bundles, the second to N layers of fiber bundles are laid around the triangular prism positioning column by a routing method;

[0018] S5, pressing and shaping the laid fiber bundles by a tablet press, and vertically pulling out the triangular prism positioning column to obtain a honeycomb wall preform;

[0019] S6, placing the honeycomb wall preform in a vacuum drying oven for drying, and using a chemical vapor deposition (CVI) process for overall densification and molding to obtain a honeycomb wall with a densification degree of 100%;

[0020] S7. Perform deposition treatment on the surface of the honeycomb wall, remove the positioning plate, and obtain the final fiber-reinforced ceramic-based / carbon-based composite honeycomb structure.

[0021] In step S1, the positioning plate and the triangular positioning column are both made of stainless steel. Preferably, the triangular through holes on the positioning plate have internal angles of 120°, 30°, and 30°, respectively; preferably, the internal angles of the triangular positioning column are 120°, 30°, and 30°, respectively, and the size is consistent with the triangular through holes on the positioning plate; the positioning plate and the triangular positioning column are auxiliary manufacturing and positioning tools, mainly used to ensure that the dimensional accuracy and positioning accuracy of each unit in the honeycomb structure remain consistent, and eliminate manufacturing cumulative errors; the bottom of the triangular positioning column has a small hole connected to the fiber bundle.

[0022] In the steps S3 and S4, the fiber bundle is a carbon fiber bundle / ceramic-based fiber bundle. Preferably, the diameter of the fiber bundle is 0.1 mm. The routing method refers to an integrated molding preparation method designed according to the shape of the fiber-reinforced ceramic-based / carbon-based composite honeycomb structure, and the fiber bundle is laid through the path (steps 3.1, 3.2 and 3.3), so that after each routing, there are only two layers of fiber bundles on any surface of each unit of the honeycomb structure, and the honeycomb wall surface of the same thickness is formed in the subsequent densification treatment to ensure the thickness consistency of the honeycomb structure.

[0023] In step S5, after the triangular prism positioning column is vertically pulled out, the fiber bundle connected at the bottom moves upward accordingly, and the fiber bundle replaces the triangular prism positioning column to position and reinforce the honeycomb wall preform. The honeycomb wall preform is a two-dimensional laminated preform or a 2.5D braided preform or a three-dimensional four-way braided preform. Preferably, the planar preform is a 2.5D braided preform, and the compressive strength, bending strength and tensile strength of the composite material are relatively high.

[0024] In the step S6, the drying temperature in the vacuum drying oven is 150°C to 200°C. Preferably, the drying temperature is 180°C. The CVI process is used to densify the preform, which is to place the preform in a deposition furnace, introduce a precursor gas into the preform voids at a certain temperature, diffuse the precursor gas from the surface of the porous preform to the inside, and undergo a gas phase pyrolysis reaction, and a multiphase deposition reaction occurs at the gas-solid interface in the preform voids. The ceramic-based composite material is deposited on the fiber surface in the form of a coating, and gaseous by-products are generated and diffused and removed from the inside of the preform to the outside. As the deposition continues, the coating becomes stacked to form a continuous ceramic-based / carbon-based composite material matrix. After the honeycomb wall preform is subjected to overall densification molding by the CVI process, the thickness of the formed fiber-reinforced ceramic-based / carbon-based composite honeycomb wall is consistent, and the contact is tight and there is no gap.

[0025] Beneficial effects:

[0026] 1. The present invention discloses a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure, which forms a unique path for laying fiber bundles through a wiring method, thereby realizing the integrated molding preparation of a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure and ensuring the thickness consistency of the honeycomb structure during the entire preparation process.

[0027] 2. The present invention discloses a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure. Through a wiring method, the contact walls of different units of the honeycomb structure are formed using an integrated molding technology to form the same common wall surface, thereby avoiding the interface peeling phenomenon commonly seen in traditional preparation methods, thereby significantly improving the overall stability of the honeycomb structure.

[0028] 3. The present invention discloses a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure, which uses a wiring method to accurately control the laying path and density of the fiber bundle around a triangular prism positioning column, thereby improving the unit size accuracy of the honeycomb structure and ensuring the consistency of the honeycomb structure units.

[0029] 4. The present invention discloses a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure, which uses a tablet press to press and shape the laid fiber bundles, and uses a chemical vapor deposition (CVI) process to perform an overall densification molding process, which has little impact on the ceramic-based / carbon-based composite material, better retains the high performance of the material itself, and further improves the high strength and high temperature resistance of the ceramic-based / carbon-based composite material's special-shaped lattice structure.

[0030] 5. The present invention discloses a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure, which adopts a wiring method, preform molding and CVI process densification to simplify the preparation process, reduce costs and improve the preparation process stability and preparation accuracy of the honeycomb structure, and facilitate large-scale production of array honeycomb structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A stainless steel positioning plate for a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure of the present invention;

[0032] Figure 2 A positioning device for a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure according to the present invention;

[0033] Figure 3 A schematic diagram of a carbon fiber bundle laying path (routing method) in a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure of the present invention;

[0034] Figure 4 A schematic diagram of a preparation method of a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure of the present invention;

[0035] Figure 5 A schematic diagram of a 3×4 honeycomb structure of a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure of the present invention.

[0036] Among them: 1—positioning plate, 2—triangular through hole, 3—triangular positioning column, 4—carbon fiber bundle, 5—honeycomb wall, 6—honeycomb structure. DETAILED DESCRIPTION

[0037] In order to better illustrate the purpose and advantages of the present invention, the invention is further described below with reference to the accompanying drawings and examples.

[0038] Embodiment 1:

[0039] This embodiment provides a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure.

[0040] Figure 1 and Figure 2 The stainless steel positioning plate 1 and the triangular positioning column 3 of the method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure disclosed in this embodiment are: Figure 3 The carbon fiber bundle laying path (routing method) of the method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure disclosed in this embodiment is: Figure 4 Schematic diagram of a preparation method of a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure disclosed in this embodiment. Figure 5 A schematic diagram of a 3×4 honeycomb structure of a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure disclosed in this embodiment.

[0041] This embodiment discloses a method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure, and the specific implementation steps are as follows:

[0042] S1. According to the design size and position of the honeycomb structure, a positioning plate 1 and a triangular positioning column 3 are prepared, and a triangular through hole 2 is processed at the corresponding position of the positioning plate;

[0043] S2. According to the number of units in the honeycomb structure, insert 40 triangular positioning columns with small holes at the bottom connecting the fiber bundles into the triangular through holes of the positioning plate and press them tightly;

[0044] S3, according to the designed size and thickness of the honeycomb structure, a carbon fiber bundle 4 with a diameter of 0.1 mm is formed into a unique path by a routing method, and the first layer of carbon fiber bundles is laid around the triangular positioning column;

[0045] 3.1. Lay transverse carbon fiber bundles 4 with a diameter of 0.1 mm along the upper and lower edges of the first, second and third rows of honeycomb structure units respectively;

[0046] 3.2. Along the left and right edges of the first and third rows of honeycomb structure units, longitudinal carbon fiber bundles 4 with a diameter of 0.1 mm are laid respectively;

[0047] 3.3. Lay a longitudinal carbon fiber bundle 4 with a diameter of 0.1 mm along the right edge of the fourth row of honeycomb structure units;

[0048] S4, according to the designed height of the honeycomb structure, based on the laid first layer of carbon fiber bundles, a unique path is formed by a routing method, and the second to N layers of carbon fiber bundles 4 with a diameter of 0.1 mm are laid again around the triangular positioning column;

[0049] S5, using a tablet press to press and shape the laid fiber bundle using a shaping pressure of 10 MPa, then vertically pull out the triangular prism positioning column 3, and use the fiber bundle to replace the triangular prism positioning column for positioning and reinforcement, to obtain a 2.5D woven structure honeycomb wall preform;

[0050] S6. Place the honeycomb wall preform in a vacuum drying oven for drying, treat it at 180°C for 1 hour, and then use the chemical vapor deposition (CVI) process for overall densification. Place the preform in a deposition furnace, and introduce precursor gas into the preform voids at 1200°C. The precursor gas diffuses from the porous preform surface to the inside, and a gas-phase pyrolysis reaction occurs. A multiphase deposition reaction occurs at the gas-solid interface in the preform voids. The ceramic-based composite material is deposited on the fiber surface in the form of a coating, and gaseous by-products are generated and diffused and discharged from the inside of the preform to the outside. As the deposition continues, the coating becomes stacked to form a continuous ceramic-based composite material matrix, and finally a honeycomb wall with a densification degree of 100% is obtained 5;

[0051] S7, performing deposition treatment on the surface of the honeycomb wall, removing the positioning plate 1, and obtaining the final 3×4 fiber reinforced ceramic-based / carbon-based composite honeycomb structure 6.

[0052] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, it should be noted that the present invention is not limited to the above two embodiments. Various changes can be made to it within the knowledge of ordinary technicians in this field, such as changing the diameter or type of the fiber bundle, or replacing the number of honeycomb structures from 3×4 to A×N. Various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the attached claims. Therefore, the present invention should not be limited to the contents disclosed in the embodiments, and the scope of protection claimed by the present invention shall be based on the scope defined in the claims.

Claims

1. A method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure, characterized in that: The following steps are included: S1. According to the designed size and position of the honeycomb structure, a positioning plate and a triangular positioning column are prepared, and a triangular through hole is processed at the corresponding position of the positioning plate; S2. According to the number of units of the honeycomb structure, insert the triangular positioning column into the triangular through hole of the positioning plate and press it tightly; S3. According to the designed size and thickness of the honeycomb structure, a fiber bundle with a suitable diameter is selected, and the first layer of fiber bundles is laid around the triangular positioning column by the wiring method; S4. According to the designed height of the honeycomb structure, based on the laid first layer of fiber bundles, the second to N layers of fiber bundles are laid around the triangular prism positioning column by a routing method; S5, pressing and shaping the laid fiber bundles by a tablet press, and vertically pulling out the triangular prism positioning column to obtain a honeycomb wall preform; S6, placing the honeycomb wall preform in a vacuum drying oven for drying, and using a chemical vapor deposition (CVI) process for overall densification and molding to obtain a honeycomb wall with a densification degree of 100%; S7. Perform deposition treatment on the surface of the honeycomb wall, remove the positioning plate, and obtain the final fiber-reinforced ceramic-based / carbon-based composite honeycomb structure.

2. The method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure according to claim 1, characterized in that: The implementation method of step S3 is: 3.

1. Lay transverse fiber bundles along the upper and lower edges of the first, second and third rows of honeycomb structure units respectively; 3.

2. Lay longitudinal fiber bundles along the left and right edges of the first and third rows of honeycomb structure units, respectively; 3.

3. Lay the longitudinal fiber bundle along the right edge of the fourth row of honeycomb structure units.

3. A method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure according to claim 1 or 2, characterized in that: In step S1, the positioning plate and the triangular positioning column are both made of stainless steel; the triangular through holes on the positioning plate have internal angles of 120°, 30°, and 30°, respectively; the internal angles of the triangular positioning column are 120°, 30°, and 30°, respectively, and the size is consistent with the triangular through holes on the positioning plate; the positioning plate and the triangular positioning column are auxiliary manufacturing and positioning tools, mainly used to ensure that the dimensional accuracy and positioning accuracy of each unit in the honeycomb structure remain consistent and eliminate manufacturing cumulative errors; the bottom of the triangular positioning column is provided with a small hole connected to the fiber bundle.

4. A method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure according to claim 1 or 2, characterized in that: In the steps S3 and S4, the fiber bundle is a carbon fiber bundle / ceramic-based fiber bundle; the diameter of the fiber bundle is 0.1 mm; the routing method refers to laying the fiber bundle through a path according to the shape of the fiber-reinforced ceramic-based / carbon-based composite honeycomb structure, so that after each routing, there are and only two layers of fiber bundles on any surface of each unit of the honeycomb structure, and the same thickness of honeycomb wall is formed in the subsequent densification treatment to ensure the thickness consistency of the honeycomb structure.

5. A method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure according to claim 1 or 2, characterized in that: In step S5, after the triangular prism positioning column is pulled out vertically upward, the fiber bundle connected at the bottom moves upward accordingly. At this time, the fiber bundle replaces the triangular prism positioning column to position and reinforce the honeycomb wall preform; the honeycomb wall preform is a two-dimensional laminated preform or a 2.5D woven preform or a three-dimensional four-way woven preform; the planar preform is a 2.5D woven preform.

6. A method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure according to claim 1 or 2, characterized in that: In the step S6, the drying temperature in the vacuum drying oven is 150° C. to 200° C.; the preform is densified by using the CVI process.

7. A method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure according to claim 6, characterized in that: The drying temperature is 180°C.

8. The method for preparing a fiber-reinforced ceramic-based / carbon-based composite honeycomb structure according to claim 6, characterized in that: The CVI process is used to densify the preform. The specific implementation method is as follows: The preform is placed in a deposition furnace, and a precursor gas is introduced into the voids of the preform at a predetermined temperature. The precursor gas diffuses from the surface of the porous preform to the inside, and a gas-phase pyrolysis reaction occurs. A multiphase deposition reaction occurs at the gas-solid interface in the voids of the preform, and the ceramic-based composite material is deposited on the fiber surface in the form of a coating. At the same time, gaseous by-products are generated and diffused and discharged from the inside of the preform to the outside. As the deposition continues, the coating becomes stacked to form a continuous ceramic-based / carbon-based composite material matrix. After the honeycomb wall preform is subjected to overall densification molding treatment through the CVI process, the thickness of the honeycomb wall of the fiber-reinforced ceramic-based / carbon-based composite material is uniform, and the contact is tight and there is no gap.

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