A near-zero expansion C / C-SiC composite material with a double-matrix partition configuration and a preparation method and application thereof

Abstract

The application discloses a near-zero expansion C / C-SiC composite material with a double-matrix partition configuration and a preparation method and application thereof, and relates to the technical field of ceramic matrix composites. The composite material comprises a carbon fiber preform, carbon matrices filled in the inside and outside of the carbon fiber preform, and a SiC matrix deposited on the carbon matrix outside the carbon fiber preform; the carbon fiber preform is woven by continuous carbon fiber bundles; and the carbon matrices are filled in the inside and outside of the carbon fiber bundles. The application introduces the continuous carbon matrix in the fiber bundle scale, and cooperatively designs the carbon matrix outside the fiber bundle and the SiC matrix, so that the carbon matrix bears the heat strain absorption and buffering effect in the thermal expansion process of the composite material.

Description

Technical Field

[0001] This invention relates to the field of ceramic matrix composites, specifically to a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, its preparation method, and its applications. Background Technology

[0002] With the continuous development of science and technology, fields such as aerospace, space exploration, and high-end optical equipment have placed higher demands on the comprehensive performance of structural materials, especially emphasizing the thermal stability and dimensional stability of materials under complex thermal environments. During service, the thermal expansion behavior of structural materials directly affects the geometric accuracy, assembly reliability, and structural safety of components. Therefore, structural materials that can maintain near-zero thermal expansion characteristics over a wide temperature range have gradually become an important research direction and engineering application requirement in related fields.

[0003] In aerospace applications, critical components such as aircraft connecting rings, thermal protection structures, and space optomechanical structural parts must withstand high-temperature airflow, frequent thermal cycling, and wide-range temperature variations. Their dimensional stability has a decisive impact on system safety and service reliability. With the continuous increase in flight speed and space exploration missions, the service temperature range faced by materials has significantly expanded. Some applications typically require materials to have a linear thermal expansion coefficient of 10 within their service temperature range. -7 K -1 The magnitude is even lower, to avoid the adverse effects of thermal deformation and thermal stress accumulation on structural accuracy and service performance.

[0004] Carbon fiber reinforced ceramic matrix composites are considered important candidate materials in the aerospace field due to their low density, low coefficient of thermal expansion, high specific strength, high specific modulus, excellent thermal conductivity, and good radiation resistance. Among them, carbon fiber reinforced silicon carbide matrix composites have attracted widespread attention in high-temperature structural applications because they combine the low thermal expansion characteristics of carbon fibers with the high-temperature stability of silicon carbide matrices. C / SiC composites are typically prepared using processes such as chemical vapor infiltration, precursor impregnation pyrolysis, or reactive melt infiltration. The linear thermal expansion coefficient of C / SiC composites obtained by these methods is generally in the range of 1.0–2.0 × 10⁻⁶. -6 K -1 The magnitude is on the order of magnitude. Although it has certain advantages compared to traditional metal materials, it is still difficult to meet the engineering requirements of high-precision structures for near-zero thermal expansion characteristics over a wide temperature range.

[0005] Existing technologies for controlling the thermal expansion behavior of C / SiC composites are relatively limited, relying mostly on passive adjustments such as fiber type, volume fraction, matrix densification degree, or the introduction of negative expansion phases. This makes it difficult to achieve precise control and wide-temperature-range stability of the coefficient of thermal expansion while ensuring material mechanical properties, structural integrity, and service reliability. Therefore, addressing the problems of high coefficient of thermal expansion, insufficient wide-temperature-range thermal stability, and limited control methods in existing carbon fiber reinforced ceramic matrix composites, there is an urgent need to propose a new preparation method or control strategy to effectively reduce and controllably adjust the coefficient of thermal expansion while considering both material mechanical properties and structural stability, in order to meet the application requirements of the aerospace field for wide-temperature-range, high-dimensional stability structural materials. Summary of the Invention

[0006] To address the shortcomings of the aforementioned background technologies, this invention primarily solves the problems of high thermal expansion coefficient, narrow near-zero thermal expansion service temperature range, and difficulty in finely controlling thermal expansion performance in carbon fiber reinforced ceramic matrix composites. This invention provides a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, its preparation method, and its applications. This method, through fine design of the carbon matrix within the fiber bundles of the composite material, achieves effective control over the material's thermal expansion behavior while ensuring the material's mechanical properties and structural integrity, thereby expanding its service applicability over a wide temperature range.

[0007] The first objective of this invention is to provide a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, the near-zero expansion C / C-SiC composite material comprising a carbon fiber preform, the interior and exterior of the carbon fiber preform being filled with a carbon matrix, and a SiC matrix deposited on the carbon matrix on the exterior of the carbon fiber preform; The carbon fiber preform is woven from continuous carbon fiber bundles. The carbon matrix is ​​filled inside and outside the carbon fiber bundle; The near-zero expansion C / C-SiC composite material is a continuous carbon fiber reinforced ceramic matrix composite material with a density of less than 2.0 g / cm³. 3 The porosity is 8~15 vol.%.

[0008] Preferably, after the carbon matrix completely fills the interior of the fiber bundle, the thickness of the carbon matrix formed on the outside of the fiber bundle is 2~15μm; the thickness of the SiC matrix deposition is 2~25μm.

[0009] Preferably, the diameter of the carbon fiber monofilaments in the carbon fiber bundle is 4 to 8 μm, and the number of monofilaments in a single carbon fiber bundle is 1K, 3K, 6K or 12K; the carbon fiber can be T series or M series carbon fiber.

[0010] Preferably, the carbon fiber preform has a two-dimensional, quasi-three-dimensional, or three-dimensional woven structure, and the volume fraction of carbon fiber in the carbon fiber preform is not less than 38 vol.

[0011] The second objective of this invention is to provide a method for preparing a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, comprising the following steps: Carbon fiber preforms are prepared by weaving carbon fiber bundles. A carbon matrix was introduced into a carbon fiber preform using a chemical vapor infiltration process to obtain a C / C preform. A near-zero expansion C / C-SiC composite material was obtained by introducing SiC matrix into a C / C preform using a chemical vapor infiltration process.

[0012] Preferably, the chemical vapor permeation temperature when introducing the carbon matrix is ​​1000~1200℃, and the reaction gases include inert gases and carbon source gases; The inert gas is argon, the carbon source gas is methane, and the deposition holding time is 30~200 h.

[0013] Preferably, the density of the C / C preform is 0.9~1.2 g / cm³. 3 The weight gain of C / C preforms relative to carbon fiber preforms is 30% to 60%.

[0014] Preferably, the SiC substrate is introduced at a temperature of 800~1200℃ and a pressure of 3~8 kPa. The reaction gases include argon, hydrogen and trichloromethylsilane, and the deposition holding time is 40~200 h.

[0015] Preferably, the flow rate of argon gas is 2-4 L / min; the flow rate of hydrogen gas is 4-6 L / min; and the molar ratio of hydrogen gas to trichloromethylsilane is 10:1.

[0016] The third objective of this invention is to provide an application of a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration in aerospace, optical devices, or sensors.

[0017] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, its preparation method, and its applications. The invention designs the matrix structure at the fiber bundle scale, preferentially introducing and distributing the carbon matrix within the fiber bundle. The carbon matrix has a relatively low elastic modulus and a certain degree of deformability. When the SiC matrix subsequently experiences positive thermal expansion strain, the carbon matrix within the fiber bundle can absorb and buffer the thermal strain through its own deformation. This macroscopically regulates the thermal expansion behavior of the composite material, which is beneficial for reducing the overall thermal expansion coefficient and achieving near-zero thermal expansion characteristics.

[0018] The method provided by this invention is based on chemical vapor infiltration, which is a mature process with good compatibility. It is also conducive to fine control of the internal structure of composite materials and is suitable for preparing ceramic matrix composite materials with high requirements for dimensional stability and thermal stability.

[0019] This invention utilizes the relatively low elastic modulus of the carbon matrix to achieve controllable adjustment of the internal stress state of the fiber bundle, alleviates and regulates the constraint effect of the ceramic matrix on the carbon fiber, and allows the axial negative thermal expansion characteristics of the carbon fiber to be more fully utilized in the composite material, thereby further reducing the overall thermal expansion coefficient of the composite material.

[0020] This invention achieves precise control over the interaction between fibers, carbon matrix, and SiC matrix through the rational design of the matrix composition and distribution state within the fiber bundle. This enables the composite material to have good designability and controllability in thermal expansion performance, meeting the near-zero thermal expansion performance requirements of different application scenarios. Attached Figure Description

[0021] Figure 1 The images shown are scanning electron microscope (SEM) images of the C / C-SiC composite materials prepared in Examples 1 to 4, wherein (a) is an SEM image of the C / C-SiC composite material prepared in Example 1, (b) is an SEM image of the C / C-SiC composite material prepared in Example 2, (c) is an SEM image of the C / C-SiC composite material prepared in Example 3, and (d) is an SEM image of the C / C-SiC composite material prepared in Example 4.

[0022] Figure 2 The diagram shows the expansion properties of the C / C-SiC composite materials prepared in Examples 1-4 in the temperature range of -90 to 80 °C, where (a) is the linear expansion curve and (b) is the expansion coefficient curve as a function of temperature.

[0023] Figure 3 The image shown is a scanning electron microscope (SEM) image of the C / C-SiC composite material prepared in Comparative Example 1.

[0024] Figure 4 This is a schematic diagram of the expansion properties of the C / C-SiC composite material prepared in Comparative Example 1 in the temperature range of -90 to 80 ℃, where (a) is the linear expansion curve and (b) is the expansion coefficient curve as a function of temperature.

[0025] Figure 5 The image shown is a scanning electron microscope (SEM) image of the C / C-SiC composite material prepared in Comparative Example 2.

[0026] Figure 6 This is a schematic diagram of the expansion properties of the C / C-SiC composite material prepared in Comparative Example 2 in the temperature range of -90 to 80 ℃, where (a) is the linear expansion curve and (b) is the expansion coefficient curve as a function of temperature. Detailed Implementation

[0027] 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.

[0028] This invention addresses existing technologies that achieve near-zero thermal expansion by constructing multi-component, multi-layer composite matrix configurations. These methods typically involve introducing low-expansion or negative-expansion phases into the matrix to counteract overall thermal deformation. This invention constructs a multi-matrix synergistic system with different mechanical response characteristics within the composite material. It proposes a dual-matrix structure control mechanism that introduces a low-modulus carbon matrix within the fiber bundle, forming a synergistic effect with a high-modulus silicon carbide matrix outside the fiber bundle. This structure controls the carbon matrix content to regulate its ratio to the silicon carbide matrix. Utilizing the deformability of the carbon matrix under thermal strain, the thermal stress generated by the silicon carbide matrix is ​​absorbed and buffered, thereby improving the stress transmission state between the fiber and the matrix, promoting the effective exertion of the negative expansion effect of carbon fibers, and achieving near-zero thermal expansion characteristics of the composite material over a wide temperature range. This provides a new technical approach for the design of near-zero expansion structural materials with high dimensional stability.

[0029] To achieve the above objectives, the first aspect of the present invention provides a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, the near-zero expansion C / C-SiC composite material comprising a carbon fiber preform, the carbon fiber preform having a carbon matrix filling its interior and exterior, and a SiC matrix deposited on the carbon matrix on the exterior of the carbon fiber preform. The carbon fiber preform is woven from continuous carbon fiber bundles. The carbon matrix is ​​filled inside and outside the carbon fiber bundle; The near-zero expansion C / C-SiC composite material is a continuous carbon fiber reinforced ceramic matrix composite material with a density of less than 2.0 g / cm³. 3The porosity is 8~15 vol.%. Continuous carbon fiber bundles are used as reinforcements to prepare carbon fiber preforms through a weaving process.

[0030] After the carbon matrix completely fills the interior of the fiber bundle, the thickness of the carbon matrix formed on the outside of the fiber bundle is 2~15 μm; the thickness of the SiC matrix deposition is 2~25 μm. The thinnest thickness of the carbon matrix formed on the outside of the fiber bundle is 2 μm and the thickest is 15 μm; the thinnest thickness of the SiC matrix deposition is 2 μm and the thickest is 25 μm.

[0031] The diameter of the carbon fiber monofilaments in the carbon fiber bundle is 4 to 8 μm, and the number of monofilaments in a single bundle is 1K, 3K, 6K or 12K; the carbon fiber can be T series or M series carbon fiber.

[0032] The carbon fiber preform has a two-dimensional, quasi-three-dimensional, or three-dimensional woven structure, and the volume fraction of carbon fiber in the carbon fiber preform is not less than 38 vol.% to ensure that the composite material has good mechanical properties and structural stability.

[0033] A second aspect of the present invention provides a method for preparing a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, comprising the following steps: Carbon fiber preforms are prepared by weaving carbon fiber bundles. A carbon matrix was introduced into a carbon fiber preform using a chemical vapor infiltration process to obtain a C / C preform. A near-zero expansion C / C-SiC composite material was obtained by introducing SiC matrix into a C / C preform using a chemical vapor infiltration process.

[0034] The chemical vapor infiltration temperature when introducing a carbon matrix is ​​1000~1200℃, and the reaction gases include inert gases and carbon source gases; The inert gas is argon, the carbon source gas is methane, and the deposition holding time is 30~200 h.

[0035] The density of C / C preforms is 0.9~1.2 g / cm³. 3 The weight gain of C / C preforms relative to carbon fiber preforms is 30% to 60%.

[0036] For example, a carbon matrix is ​​introduced into the above-mentioned carbon fiber preform using a chemical vapor infiltration process to prepare a C / C preform.

[0037] Specifically, the carbon fiber preform is placed in a chemical vapor infiltration furnace, and carbon matrix deposition is performed at a temperature of 1000–1200°C. The reaction gases include an inert gas and a carbon source gas. The inert gas is argon, and the carbon source gas is methane. The deposition holding time is 30–200 h, allowing the carbon matrix to be gradually introduced into the interior of the carbon fiber preform.

[0038] During the deposition process, the deposition thickness of the carbon matrix is ​​controlled by adjusting the deposition holding time, allowing the carbon matrix to preferentially fill the pores inside the fiber bundle. Once the carbon matrix has completely filled the fiber bundle, the deposition process is restricted to control the thickness of the carbon matrix formed on the outside of the fiber bundle, thereby creating a partitioned carbon matrix structure within the fiber bundle scale.

[0039] When the carbon fiber is a T-series carbon fiber, by adjusting the deposition and heat preservation time, the thickness of the carbon matrix formed on the outside of the fiber bundle is controlled to not exceed 15 μm after the carbon matrix completely fills the interior of the fiber bundle.

[0040] When the carbon fiber is an M-series carbon fiber, by adjusting the deposition and heat preservation time, the thickness of the carbon matrix formed on the outside of the fiber bundle is controlled to not exceed 10 μm after the carbon matrix completely fills the interior of the fiber bundle.

[0041] The carbon matrix has a relatively low elastic modulus and a certain degree of deformability, which is beneficial for buffering and coordinating the thermal strain generated between the fiber and the ceramic matrix during the subsequent introduction of the SiC matrix and the service of the composite material.

[0042] In this invention, different thicknesses of the outer carbon matrix of the fiber bundle are designed for different types of carbon fibers, mainly based on the differences in the thermal expansion behavior of different carbon fibers.

[0043] It should be noted that different series of carbon fibers have different coefficients of thermal expansion in the axial direction. Among them, M-series carbon fibers generally have a more significant negative thermal expansion characteristic in the axial direction. For example, the coefficient of thermal expansion of M55J carbon fiber is -1.1×10⁻⁶. -6 K -1 Furthermore, it can provide greater axial adaptive deformation capacity during temperature changes. Based on the above characteristics, when M-series carbon fibers are used as reinforcement, the fibers themselves can already coordinate the thermal strain mismatch in the composite material system to a certain extent. Therefore, it is not necessary to set a thick carbon matrix on the outside of the fiber bundle to achieve effective buffering of thermal strain.

[0044] In contrast, T-series carbon fibers exhibit relatively weak negative thermal expansion in the axial direction; for example, the coefficient of thermal expansion of T300 carbon fiber is -0.41 × 10⁻⁶. -6 K -1However, its adaptive ability to thermal strain mismatch during temperature changes is relatively limited. Therefore, when using T-series carbon fibers as reinforcement, by setting a relatively thick carbon matrix on the outside of the fiber bundle, the carbon matrix can undertake more deformable coordination within the fiber bundle scale. This is beneficial to achieving a match between the thermal deformation behavior of the fiber, the carbon matrix, and the SiC matrix, thereby reducing the overall thermal expansion coefficient of the composite material.

[0045] By using the above-mentioned differentiated design of carbon matrix thickness for different carbon fiber types, the thermal expansion behavior of composite materials can be finely controlled without significantly increasing the material density, which is beneficial to obtaining stable near-zero thermal expansion performance.

[0046] In this invention, the SiC substrate is introduced at a temperature of 800–1200°C and a pressure of 3–8 kPa. The reaction gases include argon, hydrogen, and trichloromethylsilane, and the deposition holding time is 40–200 h. The flow rate of argon is 2–4 L / min; the flow rate of hydrogen is 4–6 L / min; and the molar ratio of hydrogen to trichloromethylsilane is 10:1.

[0047] For example, after the preparation of the C / C preform is completed, a SiC matrix is ​​introduced into the C / C preform using a chemical vapor infiltration process, and a near-zero expansion C / C-SiC composite material is finally prepared.

[0048] The C / C-SiC composite material prepared by the above steps is a continuous carbon fiber reinforced ceramic matrix composite material with an overall density of less than 2.0 g / cm³. 3 The porosity is 8–15 vol.%.

[0049] This composite material optimizes the thermal strain transfer behavior between carbon fibers, carbon matrix, and SiC matrix by controlling the distribution state of the carbon matrix at the fiber bundle scale. This helps to reduce the thermal expansion coefficient of the composite material and expand the applicable temperature range of its near-zero thermal expansion performance.

[0050] A third aspect of the present invention provides an application of a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration in aerospace, optical devices or sensors.

[0051] It should be noted that, unless otherwise specified, the experimental methods used in this invention are all conventional methods; and the reagents and materials used, unless otherwise specified, are all commercially available.

[0052] Example 1 This embodiment provides a method for preparing a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, specifically including the following steps: (1) Preparation of carbon fiber preform: Continuous carbon fiber bundles were selected as reinforcement, wherein the diameter of the carbon fiber filament was 7 μm, the number of fibers in a single bundle was 1K, and the carbon fiber was T300 carbon fiber. 2D carbon fiber preforms were prepared by weaving process, and the volume fraction of carbon fiber in the carbon fiber preform was 40 vol.%.

[0053] (2) Preparation of carbon matrix: A carbon matrix was deposited in the carbon fiber preform using a chemical vapor infiltration process. The deposition temperature was 1100℃, and the reaction gases were argon and methane. The argon flow rate was 3 L / min, the methane flow rate was 0.75 L / min, the molar ratio of argon to methane was 4:1, and the deposition holding time was 50 h. The fiber bundle was completely filled with carbon matrix, while the thickness of the carbon matrix formed on the outside of the fiber bundle was controlled to not exceed 3 μm, thereby forming a carbon matrix partition structure within the fiber bundle scale and obtaining a C / C preform.

[0054] (3) Preparation of SiC matrix: SiC matrix was deposited in the C / C preform using chemical vapor infiltration. The deposition temperature was 1000℃, the reaction chamber pressure was 5 kPa, and the reaction gases were argon, hydrogen and trichloromethylsilane, with an argon flow rate of 3 L / min, a hydrogen flow rate of 5 L / min, a hydrogen to trichloromethylsilane molar ratio of 10:1, and a deposition holding time of 200 h, finally obtaining carbon fiber reinforced C / C-SiC composite material.

[0055] The density of the prepared C / C-SiC composite material was tested to be 1.77 g / cm³. 3 The porosity is 10.7 vol.%, and the average coefficient of thermal expansion is 0.467 × 10⁻⁶ within the temperature range of -90 to 80 °C. -6 K -1 .

[0056] Example 2 This embodiment provides a method for preparing a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, specifically including the following steps: (1) Preparation of carbon fiber preform: Continuous carbon fiber bundles were selected as reinforcement, wherein the diameter of the carbon fiber filament was 7 μm, the number of fibers in a single bundle was 1K, and the carbon fiber was T300 carbon fiber. 2D carbon fiber preforms were prepared by weaving process, and the volume fraction of carbon fiber in the carbon fiber preform was 40 vol.%.

[0057] (2) Preparation of carbon matrix: A carbon matrix was deposited in the carbon fiber preform using a chemical vapor infiltration process. The deposition temperature was 1100℃, and the reaction gases were argon and methane. The argon flow rate was 3 L / min, the methane flow rate was 0.75 L / min, the molar ratio of argon to methane was 4:1, and the deposition holding time was 80 h. The fiber bundle was completely filled with carbon matrix, while the thickness of the carbon matrix formed on the outside of the fiber bundle was controlled to not exceed 5 μm, thereby forming a carbon matrix partition structure within the fiber bundle scale and obtaining a C / C preform.

[0058] (3) Preparation of SiC matrix: SiC matrix was deposited in the C / C preform using chemical vapor infiltration. The deposition temperature was 1000℃, the reaction chamber pressure was 5 kPa, and the reaction gases were argon, hydrogen and trichloromethylsilane, with an argon flow rate of 3 L / min, a hydrogen flow rate of 5 L / min, a hydrogen to trichloromethylsilane molar ratio of 10:1, and a deposition holding time of 160 h, finally obtaining carbon fiber reinforced C / C-SiC composite material.

[0059] The density of the prepared C / C-SiC composite material was tested to be 1.73 g / cm³. 3 The porosity is 11.3 vol.%, and the average coefficient of thermal expansion is 0.005 × 10⁻⁶ within the temperature range of -90 to 80 °C. -6 K -1 .

[0060] Example 3 This embodiment provides a method for preparing a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, specifically including the following steps: (1) Preparation of carbon fiber preform: Continuous carbon fiber bundles were selected as reinforcement, wherein the diameter of the carbon fiber filament was 7 μm, the number of fibers in a single bundle was 1K, and the carbon fiber was T300 carbon fiber. 2D carbon fiber preforms were prepared by weaving process, and the volume fraction of carbon fiber in the carbon fiber preform was 40 vol.%.

[0061] (2) Preparation of carbon matrix: A carbon matrix was deposited in the carbon fiber preform using a chemical vapor infiltration process. The deposition temperature was 1100℃, and the reaction gases were argon and methane. The argon flow rate was 3 L / min, the methane flow rate was 0.75 L / min, the molar ratio of argon to methane was 4:1, and the deposition holding time was 100 h. The fiber bundle was completely filled with carbon matrix, while the thickness of the carbon matrix formed on the outside of the fiber bundle was controlled to not exceed 7 μm, thereby forming a carbon matrix partition structure within the fiber bundle scale and obtaining a C / C preform.

[0062] (3) Preparation of SiC matrix: SiC matrix was deposited in the C / C preform using chemical vapor infiltration. The deposition temperature was 1000℃, the reaction chamber pressure was 5 kPa, and the reaction gases were argon, hydrogen and trichloromethylsilane, with an argon flow rate of 3 L / min, a hydrogen flow rate of 5 L / min, a hydrogen to trichloromethylsilane molar ratio of 10:1, and a deposition holding time of 160 h, finally obtaining carbon fiber reinforced C / C-SiC composite material.

[0063] The density of the prepared C / C-SiC composite material was tested to be 1.71 g / cm³. 3 With an open porosity of 10.0 vol.%, the average coefficient of thermal expansion is 0.117 × 10⁻⁶ within the temperature range of -90 to 80 °C. -6 K -1 .

[0064] Example 4 This embodiment provides a method for preparing a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, specifically including the following steps: (1) Preparation of carbon fiber preform: Continuous carbon fiber bundles were selected as reinforcement, wherein the diameter of the carbon fiber filament was 7 μm, the number of fibers in a single bundle was 1K, and the carbon fiber was T300 carbon fiber. 2D carbon fiber preforms were prepared by weaving process, and the volume fraction of carbon fiber in the carbon fiber preform was 40 vol.%.

[0065] (2) Preparation of carbon matrix: A carbon matrix was deposited in the carbon fiber preform using a chemical vapor infiltration process. The deposition temperature was 1100℃, and the reaction gases were argon and methane. The argon flow rate was 3 L / min, the methane flow rate was 0.75 L / min, the molar ratio of argon to methane was 4:1, and the deposition holding time was 150 h. The fiber bundle was completely filled with carbon matrix, while the thickness of the carbon matrix formed on the outside of the fiber bundle was controlled to not exceed 12 μm, thereby forming a carbon matrix partition structure within the fiber bundle scale and obtaining a C / C preform.

[0066] (3) Preparation of SiC matrix: SiC matrix was deposited in the C / C preform using chemical vapor infiltration. The deposition temperature was 1000℃, the reaction chamber pressure was 5 kPa, and the reaction gases were argon, hydrogen and trichloromethylsilane, with an argon flow rate of 3 L / min, a hydrogen flow rate of 5 L / min, a hydrogen to trichloromethylsilane molar ratio of 10:1, and a deposition holding time of 160 h, finally obtaining carbon fiber reinforced C / C-SiC composite material.

[0067] The density of the prepared C / C-SiC composite material was tested to be 1.74 g / cm³. 3The porosity is 8.7 vol.%, and the average coefficient of thermal expansion is 0.351 × 10⁻⁶ within the temperature range of -90 to 80 °C. -6 K -1 .

[0068] Example 5 This embodiment provides a method for preparing a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, specifically including the following steps: (1) Preparation of carbon fiber preform: Continuous carbon fiber bundles were selected as reinforcement, wherein the diameter of the carbon fiber filament was 7 μm, the number of fibers in a single bundle was 6K, and the carbon fiber was T700 carbon fiber. 2D carbon fiber preforms were prepared by weaving process, and the volume fraction of carbon fiber in the carbon fiber preform was 40 vol.%.

[0069] (2) Preparation of carbon matrix: A carbon matrix was deposited in the carbon fiber preform using a chemical vapor infiltration process. The deposition temperature was 1100℃, and the reaction gases were argon and methane. The argon flow rate was 3 L / min, the methane flow rate was 0.75 L / min, the molar ratio of argon to methane was 4:1, and the deposition holding time was 150 h. The thickness of the carbon matrix formed on the outer side of the fiber bundle was controlled to be no more than 15 μm, thereby forming a carbon matrix partition structure within the fiber bundle scale and obtaining a C / C preform.

[0070] (3) Preparation of SiC matrix: SiC matrix was deposited in the C / C preform using chemical vapor infiltration. The deposition temperature was 1000℃, the reaction chamber pressure was 5 kPa, and the reaction gases were argon, hydrogen and trichloromethylsilane, with an argon flow rate of 3 L / min, a hydrogen flow rate of 5 L / min, a hydrogen to trichloromethylsilane molar ratio of 10:1, and a deposition holding time of 160 h, finally obtaining carbon fiber reinforced C / C-SiC composite material.

[0071] The density of the prepared C / C-SiC composite material was tested to be 1.80 g / cm³. 3 With an opening porosity of 10 vol.%, it exhibits a significantly reduced coefficient of thermal expansion in the temperature range of -90 to 80℃, with an average coefficient of expansion of -0.25 × 10⁻⁶. -6 K -1 .

[0072] Example 6 This embodiment provides a method for preparing a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, specifically including the following steps: (1) Preparation of carbon fiber preform: Continuous carbon fiber bundles were selected as reinforcement, wherein the diameter of the carbon fiber filament was 5 μm, the number of fibers in a single bundle was 6K, and the carbon fiber was M55J carbon fiber. 2D carbon fiber preforms were prepared by weaving process, and the volume fraction of carbon fiber in the carbon fiber preform was 40 vol.%.

[0073] (2) Preparation of carbon matrix: A carbon matrix was deposited in the carbon fiber preform using a chemical vapor infiltration process. The deposition temperature was 1100℃, and the reaction gases were argon and methane. The argon flow rate was 3 L / min, the methane flow rate was 0.75 L / min, the molar ratio of argon to methane was 4:1, and the deposition holding time was 30 h. The thickness of the carbon matrix formed on the outer side of the fiber bundle was controlled to be no more than 10 μm, thereby forming a carbon matrix partition structure within the fiber bundle scale and obtaining a C / C preform.

[0074] (3) Preparation of SiC matrix: SiC matrix was deposited in the C / C preform using chemical vapor infiltration. The deposition temperature was 1000℃, the reaction chamber pressure was 5 kPa, and the reaction gases were argon, hydrogen and trichloromethylsilane, with an argon flow rate of 3 L / min, a hydrogen flow rate of 5 L / min, a hydrogen to trichloromethylsilane molar ratio of 10:1, and a deposition holding time of 200 h, finally obtaining carbon fiber reinforced C / C-SiC composite material.

[0075] The density of the prepared C / C-SiC composite material was tested to be 1.83 g / cm³. 3 The porosity is 10.7 vol.%, and it exhibits a significantly reduced coefficient of thermal expansion in the temperature range of -90 to 80℃, with an average coefficient of expansion of -0.08 × 10⁻⁶. -6 K -1 .

[0076] Compare with Example 1 This comparative example provides a C / C-SiC composite material, specifically including the following steps: (1) Preparation of carbon fiber preform: Continuous carbon fiber bundles were selected as reinforcement, wherein the diameter of the carbon fiber filament was 7 μm, the number of fibers in a single bundle was 1K, and the carbon fiber was T300 carbon fiber. 2D carbon fiber preforms were prepared by weaving process, and the volume fraction of carbon fiber in the carbon fiber preform was 40 vol.%.

[0077] (2) Preparation of carbon matrix: A carbon matrix was deposited in the carbon fiber preform using a chemical vapor infiltration process. The deposition temperature was 1100℃, and the reaction gases were argon and methane. The argon flow rate was 3 L / min, the methane flow rate was 0.75 L / min, the molar ratio of argon to methane was 4:1, and the deposition holding time was 30 h. The fiber bundle was not completely filled with carbon matrix, thus obtaining a C / C preform.

[0078] (3) Preparation of SiC matrix: SiC matrix was deposited in the C / C preform using chemical vapor infiltration. The deposition temperature was 1000℃, the reaction chamber pressure was 5 kPa, and the reaction gases were argon, hydrogen, and trichloromethylsilane. The argon flow rate was 3 L / min, the hydrogen flow rate was 5 L / min, the molar ratio of hydrogen to trichloromethylsilane was 10:1, and the deposition holding time was 200 h. The fiber bundle contained SiC matrix, and carbon fiber reinforced C / C-SiC composite material was finally obtained.

[0079] The density of the prepared C / C-SiC composite material was tested to be 1.83 g / cm³. 3 The porosity is 13.3 vol.%, and the average coefficient of thermal expansion is 0.703 × 10⁻⁶ within the temperature range of -90 to 80 °C. -6 K -1 .

[0080] Compare with Example 2 This comparative example provides a C / C-SiC composite material, specifically including the following steps: (1) Preparation of carbon fiber preform: Continuous carbon fiber bundles were selected as reinforcement, wherein the diameter of the carbon fiber filament was 7 μm, the number of fibers in a single bundle was 1K, and the carbon fiber was T300 carbon fiber. 2D carbon fiber preforms were prepared by weaving process, and the volume fraction of carbon fiber in the carbon fiber preform was 40 vol.%.

[0081] (2) Preparation of SiC matrix: SiC matrix was deposited in the carbon fiber preform using chemical vapor infiltration. The deposition temperature was 1000℃, the reaction chamber pressure was 5 kPa, and the reaction gases were argon, hydrogen and trichloromethylsilane, with an argon flow rate of 3 L / min, a hydrogen flow rate of 5 L / min, a hydrogen to trichloromethylsilane molar ratio of 10:1, and a deposition holding time of 120 h, finally obtaining the C / SiC preform.

[0082] (3) Preparation of carbon matrix: A carbon matrix was deposited in the C / SiC preform using a chemical vapor infiltration process. The deposition temperature was 1100℃, and the reaction gases were argon and methane. The argon flow rate was 3 L / min, the methane flow rate was 0.75 L / min, the molar ratio of argon to methane was 4:1, and the deposition holding time was 150 h. The thickness of the carbon matrix formed on the outer side of the fiber bundle was controlled to be no more than 10 μm, thereby forming a carbon matrix partition structure on the outer scale of the fiber and obtaining the C / SiC-C preform.

[0083] (4) Preparation of SiC matrix: SiC matrix was deposited in the C / SiC-C preform using chemical vapor infiltration. The deposition temperature was 1000℃, the reaction chamber pressure was 5 kPa, and the reaction gases were argon, hydrogen, and trichloromethylsilane. The argon flow rate was 3 L / min, the hydrogen flow rate was 5 L / min, the molar ratio of hydrogen to trichloromethylsilane was 10:1, and the deposition holding time was 40 h. Finally, carbon fiber reinforced C / C-SiC composite material was obtained.

[0084] The density of the prepared C / C-SiC composite material was tested to be 2.06 g / cm³. 3 With an opening porosity of 8 vol.%, the average coefficient of thermal expansion is 0.57 × 10⁻⁶ within the temperature range of -80 to 50 °C. -6 K -1 .

[0085] Compare with Example 3 This comparative example provides a C / SiC composite material, specifically including the following steps: (1) Preparation of carbon fiber preform: Continuous carbon fiber bundles were selected as reinforcement, wherein the diameter of the carbon fiber filament was 7 μm, the number of fibers in a single bundle was 1K, and the carbon fiber was T300 carbon fiber. 2D carbon fiber preforms were prepared by weaving process, and the volume fraction of carbon fiber in the carbon fiber preform was 40 vol.%.

[0086] (2) Preparation of PyC interface layer: A PyC interface layer was deposited on the surface of the carbon fiber preform using a chemical vapor infiltration process. The deposition temperature was 900℃, the reaction chamber pressure was 5 kPa, and the reaction gases were argon and propylene, with an argon flow rate of 3 L / min and a propylene flow rate of 3 L / min. The deposition holding time was 40 h, resulting in a PyC interface layer with a thickness of approximately 100 nm.

[0087] (3) Preparation of SiC matrix: SiC matrix was deposited in carbon fiber preforms after PyC interface layer deposition using chemical vapor infiltration process. The deposition temperature was 1000℃, the reaction chamber pressure was 5 kPa, and the reaction gases were argon, hydrogen and trichloromethylsilane, with argon flow rate of 3 L / min, hydrogen flow rate of 5 L / min, and the molar ratio of hydrogen to trichloromethylsilane of 10:1. The deposition holding time was 280 h, and carbon fiber reinforced C / SiC composite material was finally obtained.

[0088] The density of the prepared C / SiC composite material was tested to be 2.05 g / cm³. 3 The porosity is 12 vol.%, and the average coefficient of thermal expansion is 0.7 × 10⁻⁶ within the temperature range of -80 to 50 °C. -6 K -1 .

[0089] Compare with Example 4 This comparative example provides a C / C composite material, specifically including the following steps: (1) Preparation of carbon fiber preform: Continuous carbon fiber bundles were selected as reinforcement, wherein the diameter of the carbon fiber filament was 7 μm, the number of fibers in a single bundle was 1K, and the carbon fiber was T300 carbon fiber. 2D carbon fiber preforms were prepared by weaving process, and the volume fraction of carbon fiber in the carbon fiber preform was 40 vol.%.

[0090] (2) Preparation of carbon matrix: Carbon matrix is ​​deposited in the carbon fiber preform using chemical vapor infiltration process.

[0091] The deposition temperature was 1100℃, and the reaction gases were argon and methane. The argon flow rate was 3 L / min, the methane flow rate was 0.75 L / min, the molar ratio of argon to methane was 4:1, and the deposition holding time was 600 h to obtain C / C composite material.

[0092] The density of the prepared C / C composite material was tested to be 1.93 g / cm³. 3 With an open porosity of 12 vol.%, the average coefficient of thermal expansion in the temperature range of -80 to 50℃ is 0.70 × 10⁻⁶. -6 K -1 .

[0093] To illustrate the structural characteristics and thermal expansion properties of the near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration provided by the present invention, its preparation method, and the resulting composite material, the following description, in conjunction with the accompanying drawings, includes examples and comparative examples.

[0094] Figure 1 These are scanning electron microscope images of the C / C-SiC composite materials prepared in Examples 1-4. Figure 1 (a~d) show the microstructures of C / C-SiC composite materials prepared with different carbon matrix deposition times. For example... Figure 1 As shown, the fiber bundles are completely filled with carbon matrix, and the carbon fibers are uniformly wrapped by the carbon matrix. A small number of pores and microcracks are observed in some areas. These microcracks mainly originate from the release of localized stress caused by thermal expansion mismatch between the carbon fibers and the matrix during deposition and heat treatment. It can also be observed that the SiC matrix is ​​mainly distributed in the outer region of the fiber bundles. With increasing carbon matrix deposition time, the thickness of the carbon matrix outside the fiber bundles gradually increases, while the thickness of the SiC matrix outside the fiber bundles gradually decreases, and the thickness ratio of the carbon matrix outside the fiber bundles to the SiC matrix also gradually increases. Figure 1 The method for determining the C / SiC thickness ratio is as follows: First, the vertical distance from the outermost fiber to the outermost carbon matrix of the fiber bundle is measured, which is taken as the thickness of the carbon matrix outside the fiber bundle; then, the thickness of the silicon carbide matrix outside the fiber bundle is measured, and the two thicknesses are divided to obtain the C / SiC matrix thickness ratio outside the fiber bundle. This ratio directly quantifies the relative distribution ratio of the carbon matrix and silicon carbide matrix outside the fiber bundle through microstructural characterization.

[0095] Figure 2 The figures show the thermal expansion properties of the C / C-SiC composite materials prepared in Examples 1-4 within a temperature range of -90 to 80°C. Figure 2 'a' represents the curve of linear expansion as a function of temperature. Figure 2 b is the curve showing the coefficient of thermal expansion as a function of temperature. It can be seen that with the increase of carbon matrix deposition time, the thickness ratio of the carbon matrix outside the fiber bundle to the SiC matrix gradually increases, and the coefficient of thermal expansion of the C / C-SiC composite material shows a trend of first decreasing and then increasing. Among them, the C / C-SiC composite materials prepared with carbon matrix deposition times of 80 h and 100 h achieved near-zero expansion, with average coefficients of thermal expansion of 0.005 × 10⁻⁶ and 0.005 × 10⁻⁶, respectively. -6 K -1 and 0.117×10 -6 K -1 .

[0096] Figure 3 This is a scanning electron microscope (SEM) image of the C / C-SiC composite material prepared in Comparative Example 1. Figure 3 As shown, a small amount of carbon matrix and SiC matrix exist inside the fiber bundle. The carbon fibers are uniformly coated with carbon matrix and SiC matrix. There are certain pores inside the fiber bundle, but no obvious cracks were observed. The fiber bundle is completely coated with SiC matrix and no carbon matrix is ​​present.

[0097] Figure 4 The figures show the thermal expansion properties of the C / C-SiC composite material prepared in Comparative Example 1 within a temperature range of -90 to 80°C. Figure 4'a' represents the curve of linear expansion as a function of temperature. Figure 4 b is the curve showing the change of the coefficient of thermal expansion with temperature. (From...) Figure 4 As can be seen, within the stated temperature range, the linear expansion of the composite material gradually increases with increasing temperature. Figure 4 As can be seen from b, its coefficient of thermal expansion is always greater than 0 throughout the entire test temperature range, and it shows an increasing trend with increasing temperature. Its average coefficient of thermal expansion is 0.703 × 10⁻⁶. -6 K -1 .

[0098] Figure 5 The image shown is a scanning electron microscope (SEM) image of the C / C-SiC composite material prepared in Comparative Example 2. Figure 5 As shown, the interior of the fiber bundle is mainly filled with SiC matrix, and the carbon fibers are covered by SiC matrix. There are certain pores in the fiber bundle, but no obvious cracks were observed. The carbon matrix is ​​mainly distributed in the outer region of the fiber bundle.

[0099] Figure 6 The curves show the thermal expansion properties of the C / C-SiC composite material prepared in Comparative Example 2 within the temperature range of -80 to 50°C. Figure 6 'a' represents the curve of linear expansion as a function of temperature. Figure 6 b is the curve showing the change of the coefficient of thermal expansion with temperature. (From...) Figure 6 As can be seen, within the stated temperature range, the linear expansion of the composite material gradually increases with increasing temperature. Figure 6 As can be seen from b, its coefficient of thermal expansion is always greater than 0 throughout the entire test temperature range, and it shows an increasing trend with increasing temperature. Its average coefficient of thermal expansion is 0.57 × 10⁻⁶. -6 K -1 .

[0100] The C / C-SiC composite material provided by this invention is prepared by chemical vapor infiltration. Its near-zero thermal expansion behavior does not originate from the intrinsic thermal expansion characteristics of a single-phase material, but is generated by the synergistic coupling regulation of thermal strain and thermal stress between multiphase matrices. As shown in Comparative Examples 3 and 4, the single-matrix C / SiC composite material and the C / C composite material both exhibit positive thermal expansion within the same temperature range and cannot achieve near-zero thermal expansion performance.

[0101] During the heating process, both the carbon matrix and the silicon carbide matrix exhibit positive thermal expansion. However, due to the significant difference in their elastic moduli (the carbon matrix has a lower elastic moduli, while the SiC matrix has a higher elastic moduli), a significant redistribution of thermal stress occurs in the continuous coupled structure. This induces the mutual cancellation of negative and positive strains in local areas, ultimately achieving near-zero thermal expansion behavior on a macroscopic scale.

[0102] This invention further discovers that a continuous and fully filled carbon matrix is ​​one of the prerequisites for achieving near-zero thermal expansion performance. After forming a continuous carbon matrix inside the fiber bundle through chemical vapor infiltration, the carbon fibers and the carbon matrix form a stable coupling structure, ensuring continuous stress transmission within the fiber bundle and avoiding localized stress concentration caused by pores or discontinuous interfaces. At the same time, a deformable buffer zone is constructed inside the fiber bundle.

[0103] Carbon fibers possess an inherent negative thermal expansion characteristic in the axial direction, a key factor in achieving near-zero thermal expansion in composite materials. However, this negative expansion behavior is easily constrained by an external high-modulus matrix. When the fiber bundle is completely filled with a low-modulus carbon matrix, the internal carbon matrix can undergo interlaminar slip and reversible deformation under heating and pressure. This effectively alleviates the radial compressive stress exerted on the carbon fibers by the external SiC matrix, reducing the degree of constraint on the carbon fibers and allowing their negative thermal expansion behavior to be fully realized. Therefore, the continuous carbon matrix inside the fiber bundle not only directly participates in thermal strain regulation but also amplifies the contribution of the carbon fiber's negative expansion to the overall thermal expansion behavior by reducing the matrix constraint effect.

[0104] As shown in Comparative Examples 1 and 2, when a SiC matrix is ​​present inside the fiber bundle, the negative thermal expansion behavior of the carbon fiber is suppressed due to the excessive constraint of the high-modulus matrix on the carbon fiber, and the composite material cannot achieve near-zero thermal expansion performance.

[0105] This invention also discovered that the thickness ratio of the outer carbon matrix to the silicon carbide matrix is ​​a key control parameter affecting the thermal expansion properties of the composite material. As the thickness ratio of the outer carbon matrix to the silicon carbide matrix gradually increases, the thermal expansion coefficient of the C / C-SiC composite material exhibits a change pattern of first decreasing and then increasing.

[0106] When the SiC matrix outside the fiber bundle has a high proportion, the SiC matrix generates positive thermal strain upon heating. Due to its high elastic modulus, it generates significant internal stress during thermal expansion, and applies significant compressive stress to the surrounding carbon matrix and carbon fibers. At this time, although the carbon matrix has a certain deformability, its volume fraction is low, making it difficult to fully offset the positive thermal expansion of the SiC matrix. The stress regulation effect is limited, and the overall coefficient of thermal expansion of the composite material is relatively high, as shown in Example 1.

[0107] When the carbon matrix outside the fiber bundle and the silicon carbide matrix reach a reasonable thickness ratio, the positive strain generated by the SiC matrix under heat is transferred to the carbon matrix through the interface. Under this compressive stress, the low-modulus carbon matrix undergoes reversible deformation, its internal interplanar spacing decreases, and the interlayer structure undergoes compressive and shear deformation, thereby inducing equivalent negative strain in the carbon matrix. At the same time, the carbon matrix applies reverse stress to the SiC matrix, partially offsetting the positive strain of the SiC matrix. The negative strain generated by the carbon matrix provides deformation space for the positive expansion of the SiC matrix. In this stage, the positive and negative strains reach a dynamic equilibrium in space and numerically, enabling the composite material to exhibit near-zero thermal expansion properties on a macroscopic scale, as shown in Examples 2 and 3.

[0108] When the thickness of the carbon matrix outside the fiber bundle increases further, the volume fraction of the SiC matrix decreases, its ability to regulate stress weakens, and the proportion of low-modulus carbon matrix in the system is too high. Although the carbon matrix can still generate a certain amount of negative strain under pressure, its own positive thermal expansion begins to dominate, which leads to the positive thermal expansion of the carbon matrix not being fully offset, and the overall thermal expansion coefficient of the composite material increases again, as shown in Example 4.

[0109] In summary, this invention introduces a continuous carbon matrix within the fiber bundle scale and synergistically designs the carbon matrix and SiC matrix outside the fiber bundle, enabling the carbon matrix to absorb and buffer thermal strain during the thermal expansion of the composite material. By controlling the content and thickness ratio of the carbon matrix and silicon carbide matrix, the distribution of thermal stress and thermal strain within the composite material is effectively adjusted, thereby enabling the C / C-SiC composite material to achieve stable near-zero thermal expansion properties over a wide temperature range.

[0110] This invention describes preferred embodiments and their effects. However, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments.

[0111] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration, characterized in that, The near-zero expansion C / C-SiC composite material includes a carbon fiber preform, a carbon matrix filling the interior and exterior of the carbon fiber preform, and a SiC matrix deposited on the carbon matrix on the exterior of the carbon fiber preform. The carbon fiber preform is woven from continuous carbon fiber bundles. The carbon matrix is ​​filled inside and outside the carbon fiber bundle; The near-zero expansion C / C-SiC composite material is a continuous carbon fiber reinforced ceramic matrix composite material with a density of less than 2.0 g / cm³. 3 The porosity is 8~15 vol.%.

2. The near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration according to claim 1, characterized in that, After the carbon matrix completely fills the interior of the fiber bundle, the thickness of the carbon matrix formed on the outside of the fiber bundle is 2~15μm; the thickness of the SiC matrix deposition is 2~25μm.

3. The near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration according to claim 1, characterized in that, The diameter of the carbon fiber monofilaments in the carbon fiber bundle is 4 to 8 μm, and the number of monofilaments in a single bundle is 1K, 3K, 6K or 12K; the carbon fiber can be T series or M series carbon fiber.

4. The near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration according to claim 1, characterized in that, The carbon fiber preform has a two-dimensional, quasi-three-dimensional, or three-dimensional woven structure, and the volume fraction of carbon fiber in the carbon fiber preform is not less than 38 vol.

5. A method for preparing a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Carbon fiber preforms are prepared by weaving carbon fiber bundles. A carbon matrix was introduced into a carbon fiber preform using a chemical vapor infiltration process to obtain a C / C preform. A near-zero expansion C / C-SiC composite material was obtained by introducing SiC matrix into a C / C preform using a chemical vapor infiltration process.

6. The method for preparing a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration according to claim 5, characterized in that, The chemical vapor infiltration temperature when introducing a carbon matrix is ​​1000~1200℃, and the reaction gases include inert gases and carbon source gases; The inert gas is argon, the carbon source gas is methane, and the deposition holding time is 30~200 h.

7. The method for preparing a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration according to claim 5, characterized in that, The density of C / C preforms is 0.9~1.2 g / cm³. 3 The weight gain of C / C preforms relative to carbon fiber preforms is 30% to 60%.

8. The method for preparing the near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration according to claim 5, characterized in that, The SiC substrate is introduced at a temperature of 800-1200℃ and a pressure of 3-8 kPa. The reaction gases include argon, hydrogen and trichloromethylsilane, and the deposition holding time is 40-200 h.

9. The method for preparing a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration according to claim 8, characterized in that, The flow rate of argon gas is 2-4 L / min; the flow rate of hydrogen gas is 4-6 L / min; and the molar ratio of hydrogen gas to trichloromethylsilane is 10:

1.

10. The application of a near-zero expansion C / C-SiC composite material with a dual-matrix partitioned configuration as described in any one of claims 1 to 4 in aerospace, optical devices, or sensors.

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