Continuous fiber-reinforced ceramic matrix composite and method of making the same

Abstract

The application belongs to the technical field of composite material preparation, and particularly relates to a continuous fiber reinforced ceramic matrix composite material and a preparation method thereof, which comprises the following steps: mixing a carbon source solution and ceramic powder to prepare slurry; depositing an interface in a fiber preform; introducing the slurry into a central region of the fiber preform by injection, and then performing solidification and cracking to obtain an intermediate; introducing the slurry into an edge region of the intermediate by vacuum impregnation and pressure impregnation, and then performing solidification and cracking to obtain an intermediate II; embedding the intermediate II with powder, and then performing RMI infiltration to obtain a densified ceramic matrix composite material. The application can prepare a porous composite material intermediate with a low open porosity in a short time, and can prepare a composite material with a high densification degree by performing RMI infiltration on the composite material intermediate.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation technology, specifically relating to a continuous fiber reinforced ceramic matrix composite material and its preparation method. Background Technology

[0002] Ceramic materials, mainly composed of transition metal compounds such as borides, carbides, silicides, and nitrides including SiC, ZrB2, HfB2, ZrC, HfC, TaN, and HfN, are a class of highly promising ablation-resistant materials. However, the inherent brittleness and low damage tolerance of ceramics greatly limit their applications. Researchers have improved their mechanical properties by introducing toughening phases to prepare composite materials. Among these, ultra-high temperature ceramic matrix composites, with their excellent ablation resistance, high specific strength, and high specific modulus, are the most promising candidate materials for extreme thermal structural components such as the nose cone and wing leading edge of hypersonic vehicles. The combination of fiber reinforcement, interface, and ultra-high temperature ceramic matrix endows composite materials with superior properties not possessed by individual components. However, existing composite material preparation processes, such as precursor impregnation pyrolysis and chemical vapor infiltration processes, have long production cycles and high production costs; reactive melting processes reduce fiber quality, significantly decreasing the mechanical properties of the material; and slurry impregnation processes require high powder particle size and high material porosity. Therefore, it is necessary to develop a new method for preparing ceramic matrix composites to significantly reduce the preparation process and its cost, so as to make up for the shortcomings of the existing process.

[0003] Reference 1, "Effect of heat flux on ablation behavior and mechanism of C / C-ZrB2-SiC composite under oxyacetylene torch flame," indicates that the deposition of pyrolytic carbon via thermochemical vapor infiltration (TCVI) requires 20–50 hours, while the PIP process requires 14 cycles to introduce ZrB2 and SiC; however, the ZrB2 powder content introduced is only 17.7 wt.%. The composite material prepared by the PIP process has a uniform component distribution, but its main drawbacks are high precursor cost and long manufacturing cycle. Reference 2, "Ablation behavior of C...", further details the process. f The statement " / ZrC-SiC-based composites fabricated by an improved reactive melt infiltration" indicates that samples prepared by the RMI melt infiltration process have the characteristics of high densification and low porosity. However, the fiber structure is damaged to some extent during the high-temperature reactive melt infiltration process, which reduces the material properties. It is evident that existing methods for preparing ceramic matrix composites cannot simultaneously achieve the advantages of short preparation time, uniform component distribution, and intact fiber structure. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a continuous fiber-reinforced ceramic matrix composite material and its preparation method. After depositing an interface layer, ceramic powder is introduced into the central region of the fiber preform using an injection molding process. Subsequently, slurry impregnation introduces the ceramic powder into the edge region of the fiber preform, achieving a uniform distribution of the ceramic matrix within the preform. Finally, densification is achieved using an RMI melt infiltration process. This invention offers advantages such as short cycle time, uniform component distribution, and intact fiber structure. During the preparation process, this invention protects the structural integrity of the fibers, improves the uniform distribution of components within the material, and significantly shortens the preparation cycle of the composite material, meeting industry demands.

[0005] The present invention is specifically implemented through the following technical solution.

[0006] This invention provides a method for preparing continuous fiber-reinforced ceramic matrix composites, comprising the following steps:

[0007] S1: Mix the carbon source solution and ceramic powder to prepare a slurry;

[0008] Deposition interface inside fiber preform;

[0009] S2: The slurry prepared in S1 is introduced into the central region of the fiber preform after S1 treatment by injection, followed by curing and pyrolysis to prepare intermediate one;

[0010] S3: The ceramic slurry prepared in S1 is introduced into the edge region of intermediate one prepared in S2 using vacuum impregnation and pressure impregnation methods, and then solidified and pyrolyzed to obtain intermediate two.

[0011] S4: The intermediate II was embedded in powder and then densified using the RMI melt infiltration process to obtain a densified ceramic matrix composite material.

[0012] Furthermore, in S1, the carbon source solution contains one or more of the following: phenolic resin (PF) powder, carboxymethyl cellulose (CMC), epoxy resin (EP), furan resin (FF), and sucrose; such carbon sources need to be converted into carbon through high-temperature pyrolysis.

[0013] The solvent is one or any combination of deionized water, anhydrous ethanol, toluene, and xylene;

[0014] The carbon source content in the carbon source solution is 30–70 wt.%.

[0015] Furthermore, carbon sources also include one or any combination of carbon powder, diamond and graphene, and carbon nanotubes. These types of carbon sources do not require high-temperature treatment of the aforementioned carbon sources.

[0016] Furthermore, in S1, the ceramic powder includes borides, carbides, or nitrides;

[0017] Borides include zirconium boride, hafnium boride, and titanium boride; carbides include silicon carbide, zirconium carbide, hafnium carbide, niobium carbide, tantalum carbide, titanium carbide, and molybdenum carbide; nitrides include boron nitride, hafnium nitride, zirconium nitride, and silicon nitride; silicides include hafnium silicide, zirconium silicide, molybdenum silicide, and yttrium silicide.

[0018] The content of ceramic powder in the slurry is 5-90 wt.%.

[0019] The ceramic powder has a particle size of 0.05–50 μm.

[0020] Furthermore, in S1, the fiber preform includes carbon fiber, SiC fiber, silicon nitride fiber, glass fiber, oxide fiber and other ceramic fiber;

[0021] The molding methods for fiber preforms include two-dimensional lamination, three-dimensional needle-punched fibers, and three-dimensional weaving;

[0022] The fiber content of the fiber preform is 10–75 vol.%.

[0023] Furthermore, in S1, the interface material is one or a combination of several of PyC, BN, SiC and Si3N4;

[0024] The deposition thickness at the interface is 100–600 nm.

[0025] Furthermore, in S2, the slurry prepared in S1 is introduced into the central region of the fiber preform after S1 treatment by injection. The slurry is arranged in a dot matrix in the central region of the fiber preform. The dot matrix can be arranged in a circular, rectangular or irregular shape, and the spacing of the dot matrix is ​​adjustable.

[0026] In S2, both the curing and pyrolysis processes are carried out in an inert gas. The curing temperature is 80–300℃, the holding time is 0.5–4h, the pyrolysis temperature is 600–1200℃, the holding time is 0.5–4h, and the heating rate is 1–10℃ / min.

[0027] Furthermore, in S2, during injection, the injection spacing in the X, Y, and Z directions is 2–10 mm, the needle inner diameter is 0.2–1 mm, the injection time of the fractional points is 0.5–2.0 s, and the injection pressure is 0.5–1.5 MPa.

[0028] It should be noted that if the needle diameter exceeds 1 mm, obvious holes will be left on the surface of the prepared composite material, which will greatly affect the bending strength and ablation resistance of the material. Therefore, the needle diameter should be controlled to not exceed 1 mm.

[0029] Furthermore, in S3, vacuum impregnation and pressure impregnation refer to first placing the intermediate in an environment with a vacuum degree lower than -0.09MPa and letting it stand, and then placing it in the ceramic slurry prepared in S1 for pressure impregnation. The pressure of pressure impregnation is 0.5 to 3MPa, and the pressure impregnation time is 0.5 to 2h.

[0030] In S3, the curing and pyrolysis process is carried out in an inert gas, with a curing temperature of 80–300℃ and a holding time of 0.5–4h, a pyrolysis temperature of 600–1200℃ and a holding time of 0.5–4h, and a heating rate of 1–10℃ / min.

[0031] Furthermore, in S4, the powder is silicon powder with a particle size of 0.5–200 μm, the mass ratio of the powder to the ceramic matrix composite intermediate is 1–5:1, the melting temperature is 1400–2000℃, and the holding time is 0.5–3 h.

[0032] The infiltrated powders include metallic silicon powder, yttrium silicon alloy, hafnium silicon alloy, and glass powder.

[0033] A second objective of this invention is to provide a continuous fiber-reinforced ceramic matrix composite material prepared by the preparation method.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] This invention proposes a continuous fiber-reinforced ceramic matrix composite material and its preparation method. The injection molding process employed in this method offers advantages such as a short cycle time and direct densification of the central region of the sample: first, a ceramic slurry with a high solid content is injected into the central region of the fiber preform; then, ceramic powder is introduced into other regions of the fiber preform through slurry impregnation, achieving uniform distribution of the ceramic slurry in the center and other regions of the preform; finally, RMI melt infiltration densification is used to obtain the composite material. Compared with traditional preparation processes, the preparation cycle of the ceramic matrix composite material using this invention is only 40–70 hours.

[0036] Specifically, the beneficial effects of this invention are reflected in the following aspects:

[0037] (1) This invention provides a method for preparing continuous fiber reinforced ceramic matrix composites. This method has the advantages of short preparation cycle, simple process with little fiber damage, low cost and high repeatability. It is a low-cost short-cycle composite material preparation technology.

[0038] (2) The ultra-high temperature ceramic matrix composite material prepared by the method of the present invention has a high degree of densification, uniform component distribution, and high relative density.

[0039] (3) By adjusting the slurry ratio, controlling the slurry viscosity, and regulating the content and type of ceramic powder, combined with process parameter adjustments, the ceramic content in the composite matrix can be controlled, thereby improving the performance of fiber-reinforced ceramic matrix composites. The flexural strength of the composite material is not less than 400 MPa, and the fracture toughness is not less than 5.5 MPa·m. 1 / 2 Under oxyacetylene ablation conditions of 2600–2700℃, the linear ablation rate is less than 3 μm / s. Attached Figure Description

[0040] Figure 1 C f Flowchart (a) and mechanism diagram (b) of the preparation of SiC-ZrB2 composite material.

[0041] Figure 2 Injecting C in Example 1 f CT images of SiC-ZrB2 composite material: (a) XZ plane; (b) XY plane; (c) 3D matrix distribution.

[0042] Figure 3 Example 1C f Microscopic morphology of the SiC-ZrB2 composite intermediate.

[0043] Figure 4 This is a microscopic morphology diagram of the carbon fiber preform in Example 1.

[0044] Figure 5 Example 1C f Microstructure of the SiC-ZrB2 composite material. Detailed Implementation

[0045] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.

[0046] Unless otherwise specified, the experimental and detection methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0047] A method for preparing a continuous fiber-reinforced ceramic matrix composite material includes the following steps:

[0048] S1: Mix the carbon source solution and ceramic powder to prepare a slurry;

[0049] Deposition interface inside fiber preform;

[0050] S2: The slurry prepared in S1 is introduced into the central region of the fiber preform after S1 treatment by injection, and then solidified and pyrolyzed to prepare intermediate one;

[0051] S3: The ceramic slurry prepared in S1 is introduced into the edge region of intermediate one prepared in S2 using vacuum impregnation and pressure impregnation methods, and then solidified and pyrolyzed to obtain intermediate two.

[0052] S4: Intermediate II was prepared by embedding S3 with powder, and then densified by RMI melt infiltration process to obtain a densified ceramic matrix composite material.

[0053] The carbon source is either a first-class carbon source or a second-class carbon source. The first-class carbon source is one or more of phenolic resin powder, carboxymethyl cellulose, epoxy resin, furan resin, and sucrose; the second-class carbon source is one or more of carbon powder, diamond, graphene, and carbon nanotubes.

[0054] The ceramic powder is a boride, carbide, or nitride.

[0055] Fiber preforms include carbon fiber, SiC fiber, silicon nitride fiber, glass fiber, oxide fiber or other ceramic fiber; the forming methods of fiber preforms include two-dimensional lamination, three-dimensional needle-punched fiber and three-dimensional weaving.

[0056] The following uses C f Taking the SiC-ZrB2 composite material as an example, the preparation of the above composite material is explained, such as... Figure 1 As shown, the specific preparation steps are as follows:

[0057] Step 1: Deposit the interface of the needle-punched carbon fiber preform using chemical vapor infiltration, controlling the interface thickness to be between 100 and 600 nm.

[0058] Step 2: Prepare a phenolic resin solution with a concentration of 30–70 wt.%, add ZrB2 powder with a particle size of 0.5–5 μm and mix evenly to obtain a ceramic slurry. Then, ball mill the slurry using a drum ball mill at a speed of 100–300 r / min for 12–24 h to obtain the final ceramic slurry. The final ceramic slurry was obtained at 41.80 s. -1 At the shear rate, the viscosity is 100-1200 mPa·s;

[0059] Step 3: The slurry obtained in Step 2 is injected into the carbon fiber preform from Step 1 using a dot-matrix injection machine to obtain an injection preform. The injection spacing in the X, Y, and Z directions is 2–10 mm, the needle inner diameter is 0.2–1 mm, the injection time for each dot is 0.5–2.0 s, the injection pressure is 0.5–1.5 MPa, and the injection volume is 0.3–1.2 cm³. 3 .

[0060] Step 4: The injection preform obtained in Step 3 is solidified at 150-300℃ and held for 1-2 hours, then pyrolyzed at 600-1200℃ and held for 1-4 hours. The heating rate is 2-5℃ / min, and the entire process is carried out in an Ar gas fluid medium.

[0061] Step 5: C from step 4 is pyrolyzed. f The SiC-ZrB2 composite intermediate was vacuum impregnated and pressure impregnated in the ceramic slurry obtained in step 2. The vacuum impregnation was performed with a vacuum level controlled below -0.09 MPa and an impregnation time of 0.5–1.5 h; the pressure impregnation was performed with a pressure controlled between 0.5 and 3 MPa and an impregnation time of 0.5–2 h.

[0062] Step 6: Repeat the curing and pyrolysis process of Step 4 to obtain semi-densified C with an open porosity of 15-40%. f / SiC-ZrB2 composite intermediate.

[0063] Step 7: Apply the semi-densified C obtained in Step 6 f The SiC-ZrB2 composite intermediate was placed in silicon powder with a particle size of 0.5–25 μm, and the quality of the silicon powder and the semi-densified C were controlled. f The SiC-ZrB2 composite intermediate has a mass ratio of (1-5):1. It is densified by reactive melting process with a melting temperature of 1400-1700℃ and a reaction time of 2-3h. Finally, carbon fiber reinforced ultra-high temperature ceramic matrix composite is obtained.

[0064] The above content will be specifically explained through the following examples.

[0065] Example 1

[0066] Step 1: Slurry preparation.

[0067] Take 40g of phenolic resin powder and add it to a beaker containing 60g of anhydrous ethanol. Stir the mixture for 30min at 1000r / min using a magnetic stirrer to obtain a uniform and stable phenolic resin solution. Take 60g of ZrB2 powder with a particle size of 1-3μm and add it to a beaker containing 40g of phenolic resin solution. Stir the mixture for 30min at 1200r / min using a magnetic stirrer, and then ball mill it at 120r / min for 12h to obtain a uniform and stable ZrB2 ceramic slurry.

[0068] Step 2: The needle-punched carbon fiber preform is deposited with a pyrolytic carbon PyC interface using chemical vapor infiltration. When the interface thickness reaches 100 nm, the deposition is stopped and heat treatment is performed.

[0069] Step 3: The ZrB2 ceramic slurry obtained in Step 1 is introduced into the carbon fiber preform after deposition in Step 2 using a dispensing machine. The needle inner diameter is 0.9 mm, the distance between injection points in the X and Y directions is 5 mm, the distance between injection points in the Z direction is 5 mm, the injection time is 0.5 s, and the injection pressure is 0.5 MPa.

[0070] Step 4: The composite material obtained in Step 3 was cured in a vacuum tube furnace with Ar gas as the fluid medium at a heating rate of 5℃ / min, a curing temperature of 200℃, a holding time of 2h, a pyrolysis temperature of 1000℃, and a holding time of 3h, to prepare a product with a density of 1.2 g / cm³. 3 Porous C f / SiC-ZrB2 composite intermediates (such as Figure 3 (As shown).

[0071] Step 5: Slurry impregnation

[0072] The slurry impregnation process consists of two steps: vacuum impregnation and pressure impregnation. First, the composite material from step 4 is placed in a glass desiccator, and a vacuum is applied until the pressure inside the desiccator is below -0.09 MPa. After maintaining this pressure for 30 minutes, the porous composite intermediate is immersed in the ZrB2 ceramic slurry from step 1 and held for 30 minutes. Subsequently, the slurry and the composite material are placed in a sealed container, pressurized to 0.5 MPa, and held for 0.5 hours. After this, the preform is removed, its surface is wiped dry, and then dried.

[0073] Step 6: Repeat the curing and cracking process of step 4.

[0074] Step 7: In-situ generation of SiC via reactive melt infiltration: Using an embedding method, the prepared carbon fiber composite intermediate and silicon powder with a particle size of 0.5–25 μm are placed in a graphite crucible and placed in a vacuum infiltration furnace. The reactive melt infiltration process occurs under vacuum, with a holding temperature of 1400℃ and a holding time of 30 min. The mass ratio of silicon powder to ceramic matrix composite intermediate is 1:1, thus completing the SiC generation process. f Preparation of / SiC-ZrB2 samples.

[0075] Comparative Example 1

[0076] Step 1: Prepare a product with a density of 1.4 g / cm³ using the CVI process. 3 The porous C / SiC composite preform has a pyrolytic carbon interface layer thickness of 150nm to 250nm, an open porosity of about 40%, a carbon fiber volume fraction of about 30%, and is ultrasonically cleaned with alcohol as the cleaning agent for 1 hour and dried at 150℃ for 1 hour.

[0077] Step 2: Using 50 mL xylene, 4 mL liquid PCS, 30 g ZrB2 powder, and dispersant BYK-057 (3% by mass of powder, 0.95 g), the slurry was ultrasonically dispersed for 1 h and then ball-milled at 250 r / min for 12 h.

[0078] Step 3: Vacuum impregnate the porous C / SiC composite preform with slurry for 0.5 h at a vacuum degree of -0.09 MPa, then impregnate the vacuum-impregnated composite material again for 1 h at a pressure of 0.8 MPa, and then dry it at 150 °C for 1 h.

[0079] Step 4: Repeat step 3 until the weight gain of the sample does not exceed 3%.

[0080] Step 5: Prepare a mixed solution of SiC precursor and organic solvent in a mass ratio of 1:1. The organic solvent is xylene. The composite material obtained in step 4 is vacuum pressure impregnated with this mixed solution. The vacuum pressure impregnation step 3 is the same. The pyrolysis process is a heating rate of 5℃ / min, a pyrolysis temperature of 1400℃, and a pyrolysis time of 2h.

[0081] Step 6: Repeat step 5 three times to achieve final densification.

[0082] C prepared in Comparative Example 1 f The apparent density of the ZrB2-SiC composite material can reach 2.40 g / cm³. 3 The porosity is less than 13%, and the volume fraction of ZrB2 matrix in the composite material is approximately 15%. The flexural strength is 230–400 MPa, and the fracture toughness is 1.39–8.20 MPa·m. 1 / 2 According to the test standard of GJB323B-2018 ablation test method for ablation materials, the linear ablation rate under the condition of oxyacetylene ablation at 2200℃ for 30s is about 3.1μm / s.

[0083] Compared with Comparative Example 1, Example 1 prepared C f The SiC-ZrB2 composite material has a cycle time of only 40 hours, an ultra-high temperature powder content of 20 vol.%, a relative density of 92.4%, a flexural strength increase of 25%, and an ablation resistance increase of 80%. Under oxyacetylene ablation conditions of 2600–2700℃, the linear ablation rate is less than 3 μm / s. Figure 2 Injecting C in Example 1 f CT images of the SiC-ZrB2 composite material: (a) XZ plane; (b) XY plane; (c) 3D matrix distribution; it can be seen that the components are evenly distributed. Figure 3 Example 1C f Microstructure of SiC-ZrB2 composite intermediate; Figure 4This is a microscopic morphology diagram of the carbon fiber preform in Example 1; Figure 5 Example 1C f The microstructure of the SiC-ZrB2 composite material shows that the components are evenly distributed and the fiber structure is intact.

[0084] This invention demonstrates that while protecting the structural integrity of the fibers and improving the uniform distribution of internal components during the preparation process, it also significantly shortens the preparation cycle of the composite material, thus meeting industry demands.

[0085] Example 2

[0086] Step 1: Slurry preparation.

[0087] Take 50g of phenolic resin powder and put it into a beaker containing 50g of anhydrous ethanol. Stir it on a magnetic stirrer at 1000r / min for 30min to obtain a uniform and stable phenolic resin solution. Take 60g of ZrB2 powder with a particle size of 0.5-3um and add it into a beaker containing 40g of phenolic resin solution. Stir it on a magnetic stirrer at 1200r / min for 30min. Then, ball mill it at 120r / min for 12h to obtain a uniform and stable ZrB2 ceramic slurry.

[0088] Step 2: The needle-punched carbon fiber preform is deposited with a pyrolytic carbon PyC interface using chemical vapor infiltration. When the interface thickness reaches 600 nm, the deposition is stopped and heat treatment is performed.

[0089] Step 3: The ZrB2 ceramic slurry obtained in Step 1 is introduced into the carbon fiber preform after deposition in Step 2 using a dispensing machine. The needle inner diameter is 0.9 mm, the distance between injection points in the X and Y directions is 5 mm, the distance between injection points in the Z direction is 5 mm, the injection time is 2 s, and the injection pressure is 1.5 MPa.

[0090] Step 4: The composite material obtained in Step 3 was cured in a vacuum tube furnace with Ar gas as the fluid medium at a heating rate of 5℃ / min, a curing temperature of 200℃, a holding time of 2h, a pyrolysis temperature of 1000℃, and a holding time of 3h, to prepare a product with a density of 1.3 g / cm³. 3 C f / SiC-ZrB2 composite intermediate.

[0091] Step 5: Slurry impregnation

[0092] The slurry impregnation process consists of two steps: vacuum impregnation and pressure impregnation. First, the composite material from step 4 is placed in a glass desiccator, and a vacuum is applied until the pressure inside the desiccator is below -0.1 MPa. After maintaining this pressure for 30 minutes, the porous composite intermediate is immersed in the ZrB2 ceramic slurry from step 1 and held for 30 minutes. Subsequently, the slurry and composite material are placed together in a sealed container, pressurized to 3 MPa, and held for 1.5 hours. After this, the preform is removed, its surface is wiped dry, and then dried.

[0093] Step 6: Repeat the curing and cracking process of step 4.

[0094] Step 7: In-situ generation of SiC via reactive melt infiltration: Using an embedding method, the prepared carbon fiber composite material and silicon powder with a particle size of 0.5–25 μm are placed in a graphite crucible and placed in a vacuum infiltration furnace. The reactive melt infiltration process occurs under vacuum, with a holding temperature of 1700℃ and a holding time of 30 min. The mass ratio of silicon powder to the ceramic matrix composite intermediate is 5:1, thus completing the SiC generation process. f Preparation of / SiC-ZrB2 samples.

[0095] The C prepared by this invention f The SiC-ZrB2 composite material requires only one impregnation process, which greatly shortens the preparation time and reduces the preparation cost compared with PIP and other processes.

[0096] Example 3

[0097] Step 1: Slurry preparation.

[0098] Take 50g of phenolic resin powder and put it into a beaker containing 50g of anhydrous ethanol. Stir it on a magnetic stirrer at 1000r / min for 30min to obtain a uniform and stable phenolic resin solution. Take 70g of ZrB2 powder with a particle size of 0.5-3μm and add it into a beaker containing 30g of phenolic resin solution. Stir it on a magnetic stirrer at 1200r / min for 30min. Then, ball mill it at 120r / min for 12h to obtain a uniform and stable ZrB2 ceramic slurry.

[0099] Step 2: The needle-punched carbon fiber preform is deposited with a pyrolytic carbon PyC interface using chemical vapor infiltration. When the interface thickness reaches 600 nm, the deposition is stopped and heat treatment is performed.

[0100] Step 3: The ZrB2 ceramic slurry obtained in Step 1 is introduced into the carbon fiber preform after deposition in Step 2 using a dispensing machine. The needle inner diameter is 0.9 mm, the distance between injection points in the X and Y directions is 5 mm, the distance between injection points in the Z direction is 5 mm, the injection time is 1 s, and the injection pressure is 1 MPa.

[0101] Step 4: The composite material obtained in Step 3 was cured in a vacuum tube furnace with Ar gas as the fluid medium at a heating rate of 5℃ / min, a curing temperature of 200℃, a holding time of 2h, a pyrolysis temperature of 1000℃, and a holding time of 3h, to prepare a product with a density of 1.5 g / cm³. 3 Porous C f / SiC-ZrB2 composite intermediate.

[0102] Step 5: Slurry impregnation

[0103] The slurry impregnation process consists of two steps: vacuum impregnation and pressure impregnation. First, the composite material from step 4 is placed in a glass desiccator, and a vacuum is applied until the pressure inside the desiccator is below -0.09 MPa. After maintaining this pressure for 30 minutes, the porous composite intermediate is immersed in the ZrB2 ceramic slurry from step 1 and held for 30 minutes. Subsequently, the slurry, along with the carbon fiber preform, is placed in a sealed container, pressurized to 2 MPa, and held for 1 hour. After this, the preform is removed, its surface is wiped dry, and then dried.

[0104] Step 6: Repeat the curing and cracking process of step 4.

[0105] Step 7: In-situ generation of SiC via reactive melt infiltration: Using an embedding method, the prepared composite intermediate and silicon powder with a particle size of 0.5–25 μm are placed in a graphite crucible and placed in a vacuum infiltration furnace. The reactive melt infiltration process occurs under vacuum, with a holding temperature of 1500℃ and a holding time of 30 min, thereby completing the SiC generation process. f Preparation of / SiC-ZrB2 samples.

[0106] Compared with Comparative Example 1, the C prepared in this embodiment f The content of ultra-high temperature powder in the SiC-ZrB2 composite material is 25 Vol., which improves the ablation resistance by 120%.

[0107] Example 4

[0108] Step 1: Slurry preparation.

[0109] Take 50g of phenolic resin powder and put it into a beaker containing 50g of anhydrous ethanol. Stir it on a magnetic stirrer at 1000r / min for 30min to obtain a uniform and stable phenolic resin solution. Take 70g of ZrB2 powder with a particle size of 0.5-3μm and add it into a beaker containing 30g of phenolic resin solution. Stir it on a magnetic stirrer at 1200r / min for 30min. Then, ball mill it at 120r / min for 12h to obtain a uniform and stable ZrB2 ceramic slurry.

[0110] Step 2: The needle-punched carbon fiber preform is deposited with a pyrolytic carbon PyC interface using chemical vapor infiltration. When the interface thickness is 100-600 nm, the deposition is stopped and heat treatment is performed.

[0111] Step 3: The ZrB2 ceramic slurry obtained in Step 1 is introduced into the carbon fiber preform after deposition in Step 2 using a dispensing machine. The needle inner diameter is 0.9 mm, the distance between injection points in the X and Y directions is 3 mm, the distance between injection points in the Z direction is 3 mm, the injection time is 1 s, and the injection pressure is 1 MPa.

[0112] Step 4: The composite material obtained in Step 3 was cured in a vacuum tube furnace with Ar gas as the fluid medium at a heating rate of 5℃ / min, a curing temperature of 200℃, a holding time of 2h, a pyrolysis temperature of 1000℃, and a holding time of 3h, to prepare a product with a density of 1.65 g / cm³. 3 C f / SiC-ZrB2 composite intermediate.

[0113] Step 5: Slurry impregnation

[0114] The slurry impregnation process consists of two steps: vacuum impregnation and pressure impregnation. First, the composite material from step 4 is placed in a glass desiccator, and a vacuum is applied until the pressure inside the desiccator is below -0.09 MPa. After maintaining this pressure for 30 minutes, the porous composite intermediate is immersed in the ZrB2 ceramic slurry from step 1 and held for 30 minutes. Subsequently, the slurry and composite material are placed together in a sealed container, pressurized to 2 MPa, and held for 1 hour. After this, the preform is removed, its surface is wiped dry, and then dried.

[0115] Step 6: Repeat the curing and cracking process of step 4.

[0116] Step 7: In-situ generation of SiC via reactive melt infiltration: Using an embedding method, the prepared carbon fiber composite material and silicon powder with a particle size of 0.5–25 μm are placed in a graphite crucible and placed in a vacuum infiltration furnace. A reactive melt infiltration process occurs under vacuum, with holding time and temperature of 1400–1700 °C and 30 min, respectively, thereby completing the SiC generation process. f Preparation of / SiC-ZrB2 samples.

[0117] Compared to Example 3, this embodiment shows C after injection. f The bulk density of the SiC-ZrB2 composite intermediate was increased by 16.2%, and its ablation resistance was improved by 70%.

[0118] Comparative Example 2

[0119] Step 1: Slurry preparation.

[0120] Take 50g of phenolic resin powder and put it into a beaker containing 50g of anhydrous ethanol. Stir it on a magnetic stirrer at 1000r / min for 30min to obtain a uniform and stable phenolic resin solution. Take 70g of ZrB2 powder with a particle size of 0.5-3μm and add it into a beaker containing 30g of phenolic resin solution. Stir it on a magnetic stirrer at 1200r / min for 30min. Then, ball mill it at 120r / min for 12h to obtain a uniform and stable ZrB2 ceramic slurry.

[0121] Step 2: The needle-punched carbon fiber preform is deposited with a pyrolytic carbon PyC interface using chemical vapor infiltration. When the interface thickness reaches 600 nm, the deposition is stopped and heat treatment is performed.

[0122] Step 3: The ZrB2 ceramic slurry obtained in Step 1 is introduced into the carbon fiber preform after deposition in Step 2 using a dispensing machine. The needle inner diameter is 1.45 mm, the distance between injection points in the X and Y directions is 5 mm, the distance between injection points in the Z direction is 5 mm, the injection time is 1 s, and the injection pressure is 1 MPa.

[0123] Step 4: The composite material obtained in Step 3 was cured in a vacuum tube furnace with Ar gas as the fluid medium at a heating rate of 5℃ / min, a curing temperature of 200℃, a holding time of 2h, a pyrolysis temperature of 1000℃, and a holding time of 3h, to prepare a product with a density of 1.65 g / cm³. 3 C f / SiC-ZrB2 composite intermediate.

[0124] Step 5: Slurry impregnation

[0125] The slurry impregnation process consists of two steps: vacuum impregnation and pressure impregnation. First, the composite material from step 4 is placed in a glass desiccator, and a vacuum is applied until the pressure inside the desiccator is below -0.09 MPa. After maintaining this pressure for 30 minutes, the porous composite intermediate is immersed in the ZrB2 ceramic slurry from step 1 and held for 30 minutes. Subsequently, the slurry, along with the carbon fiber preform, is placed in a sealed container, pressurized to 2 MPa, and held for 1 hour. After this, the preform is removed, its surface is wiped dry, and then dried.

[0126] Step 6: Repeat the curing and cracking process of step 4.

[0127] Step 7: In-situ generation of SiC via reactive melt infiltration: Using an embedding method, the prepared carbon fiber composite material and silicon powder with a particle size of 0.5–200 μm are placed in a graphite crucible and placed in a vacuum infiltration furnace. The reactive melt infiltration process occurs under vacuum, with a holding temperature of 1500℃ and a holding time of 30 min. The mass ratio of silicon powder to the ceramic matrix composite intermediate is 3:1, thereby completing the SiC generation process. fPreparation of / SiC-ZrB2 samples.

[0128] Comparative Example 2 compared to Example 3 after injection C f The bulk density and open porosity of the SiC-ZrB2 composite intermediate are similar, but due to the needle diameter exceeding 1 mm, the prepared C... f The surface of the SiC-ZrB2 composite material has obvious pores, which greatly affects the bending strength and ablation resistance of the material.

[0129] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, it is intended to include any modifications and variations that fall within the scope of the claims and their equivalents.

Claims

1. A method for preparing a continuous fiber-reinforced ceramic matrix composite material, characterized in that, Includes the following steps: S1: Mix the carbon source solution and ceramic powder to prepare a slurry; Deposition interface inside fiber preform; S2: The slurry prepared in S1 is introduced into the central region of the fiber preform after S1 treatment by injection, followed by curing and pyrolysis to prepare intermediate one; S3: Using vacuum impregnation and pressure impregnation, the ceramic slurry prepared in S1 is introduced into the area of ​​intermediate one in S2 except for the central region, and then cured and pyrolyzed to obtain intermediate two; S4: Intermediate II was embedded in powder and then densified using the RMI melt infiltration process to obtain a densified ceramic matrix composite material. In S2, the slurry is arranged in a lattice in the central region of the fiber preform. The injection lattice can be arranged in a circular, rectangular or irregular shape. During injection, the inner diameter of the needle is 0.2~1 mm.

2. The preparation method according to claim 1, characterized in that, In S1, the carbon source solution contains either a first type of carbon source or a second type of carbon source. The first type of carbon source is one or more of phenolic resin, carboxymethyl cellulose, epoxy resin, furan resin, and sucrose; the second type of carbon source is one or more of carbon powder, diamond, graphene, and carbon nanotubes. The solvent is one or more of water, anhydrous ethanol, toluene, and xylene; The carbon source content in the carbon source solution is 30~70 wt.%.

3. The preparation method according to claim 1, characterized in that, In S1, the ceramic powder is a boride, carbide, or nitride; The content of ceramic powder in the slurry is 5~90 ​​wt.%; The ceramic powder has a particle size of 0.05~50μm.

4. The preparation method according to claim 1, characterized in that, In S1, the fiber preform is carbon fiber, SiC fiber, silicon nitride fiber, glass fiber, or oxide fiber. The fiber preforms are formed by two-dimensional lamination, three-dimensional needle-punched fibers, or three-dimensional weaving. The fiber content of the fiber preform is 10~75 vol.%.

5. The preparation method according to claim 1, characterized in that, In S1, the interface material is one or more of PyC, BN, SiC, and Si3N4; The deposition thickness at the interface is 100~600 nm.

6. The preparation method according to claim 1, characterized in that, In S2, both the curing and pyrolysis processes are carried out in an inert gas atmosphere. The curing temperature is 80~300 ℃ and the holding time is 0.5~4 h. The pyrolysis temperature is 600~1200 ℃ and the holding time is 0.5~4 h.

7. The preparation method according to claim 6, characterized in that, In S2, during injection, the injection spacing in the X, Y, and Z directions is 2~10 mm, the injection time of the array points is 0.5~2.0 s, and the injection pressure is 0.5~1.5 MPa.

8. The preparation method according to claim 1, characterized in that, In S3, vacuum impregnation and pressure impregnation refer to first placing intermediate one in an environment with a vacuum degree lower than -0.09 MPa and letting it stand, and then placing it in the ceramic slurry prepared in S1 for pressure impregnation. The pressure of pressure impregnation is 0.5~3 MPa and the pressure impregnation time is 0.5~2 h. In S3, the curing and pyrolysis process is carried out in an inert gas atmosphere. The curing temperature is 80~300 ℃ and the holding time is 0.5~4 h. The pyrolysis temperature is 600~1200 ℃ and the holding time is 0.5~4 h.

9. The preparation method according to claim 1, characterized in that, In S4, the powder is silicon powder with a particle size of 0.5~200 μm, and the mass ratio of the powder to intermediate II is 1~5:

1. In S4, the melting and infiltration temperature is 1400~2000 ℃, and the holding time is 0.5~3 h.

10. The continuous fiber-reinforced ceramic matrix composite material prepared by the preparation method according to any one of claims 1-9.

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