Method for preparing C / C-SiC composite material by multistage recovery of carbon / carbon composite material processing waste material

Abstract

The invention discloses a method for preparing a C / C-SiC composite material through multi-stage recovery of carbon / carbon composite material processing waste, and belongs to the technical field of C / C composite material preparation. The method comprises the following steps: carrying out multi-stage screening treatment on the carbon / carbon composite material processing waste, and screening and separating short carbon fibers and pyrolytic carbon powder; mixing the screened short carbon fibers and pyrolytic carbon powder with phenolic resin, industrial silicon powder and SiC powder, and preparing a fiber reinforced resin block in a mold pressing manner; and carrying out one-step continuous carbonization and ceramic heat treatment on the fiber reinforced resin block to finally obtain the C / C-SiC composite material. According to the method, high-added-value recycling of the C / C processing waste is achieved, the process is simple, the cost is low, operation is convenient and fast, the problems of resource waste and environmental pollution caused by existing waste treatment are solved, and the prepared C / C-SiC composite material is excellent in performance and can be widely applied to the fields of aerospace, high-end manufacturing and the like.

Description

Technical Field

[0001] This invention belongs to the field of carbon / carbon composite material preparation technology, specifically relating to a method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste. Background Technology

[0002] Carbon / carbon (C / C) composites, with their unique high-temperature resistance (capable of stable operation in environments above 1000℃ for extended periods, and maintaining excellent performance even in inert atmospheres above 2000℃) and lightweight yet high-strength properties (density of only 1.3-1.8 g / cm³, with specific strength and specific modulus far exceeding traditional metals and ceramics), have become indispensable key materials in national strategic industries such as aerospace, new energy, and high-end manufacturing. In the aerospace field, C / C composites are widely used in core components such as aircraft brake discs, engine nozzles, and spacecraft heat shields, significantly reducing equipment weight and improving its high-temperature resistance and service reliability. In the new energy field, they are used in components such as fuel cell electrodes and solar thermal power generation receivers, effectively improving energy conversion efficiency and equipment lifespan. In high-end manufacturing, they serve as structural components and wear-resistant parts for precision instruments and high-speed machinery, meeting the stringent material performance requirements of high-end equipment.

[0003] However, due to the unique manufacturing process of C / C composites, multiple core steps are typically required, including preform weaving, chemical vapor deposition (CVD), and liquid-phase impregnation carbonization. The final product then undergoes further machining processes such as cutting, grinding, and drilling to meet dimensional accuracy and surface quality requirements, depending on the specific application. Due to the inherent structural characteristics of C / C composites, fiber breakage and matrix detachment are common during processing, inevitably generating significant amounts of processing waste. The main components of C / C composite processing waste are short carbon fibers and pyrolytic carbon powder. Short carbon fibers retain the high strength and high modulus of the original long carbon fibers, with tensile strength exceeding 2000 MPa and elastic modulus exceeding 200 GPa, making them a high-quality reinforcing phase material. Pyrolytic carbon powder possesses excellent lubricity, wear resistance, and thermal conductivity, making it an excellent tribological material and matrix filler; both have high reuse value. However, the current methods for handling C / C composite material processing waste are rather crude, mainly involving direct disposal or sanitary landfill, which has caused serious environmental pollution and resource waste.

[0004] In summary, as the application of C / C composite materials in industry becomes increasingly widespread, the amount of processing waste generated continues to rise. The resource waste and environmental pollution caused by existing extensive treatment methods are becoming increasingly prominent, and have become a bottleneck restricting industrial development. Furthermore, existing resource utilization technologies suffer from drawbacks such as complex processes, high costs, low added value, and lack of systematic approach, failing to meet the needs of green industrial development and struggling to solve the current waste treatment dilemma. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide a method for preparing C / C-SiC composite materials by multi-stage recycling of carbon / carbon composite material processing waste, so as to solve the environmental pollution and resource waste caused by C / C composite material processing waste in existing production.

[0006] To achieve the above objectives, the present invention employs the following technical solution: This invention discloses a method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste. The method includes: performing multi-stage sieving on the carbon / carbon composite material processing waste to screen out short carbon fibers and pyrolytic carbon powder; mixing the short carbon fibers, pyrolytic carbon powder, phenolic resin, industrial silicon powder, and SiC powder by molding to obtain a mixed powder; pressing the mixed powder into fiber-reinforced resin blocks; and then subjecting the fiber-reinforced resin blocks to a one-step continuous carbonization and ceramicization heat treatment to obtain C / C-SiC composite materials. SiC composite materials.

[0007] Preferably, during the multi-stage sieving, the mesh size of the sieve used in each sieving process increases progressively.

[0008] More preferably, the multi-stage sieving includes three-stage sieving.

[0009] More preferably, the first-stage screen is selected with a mesh size of 10-18, the second-stage screen with a mesh size of 18-200, and the third-stage screen with a mesh size of 300.

[0010] Preferably, a method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste includes the following steps: S1, the waste material from carbon / carbon composite material processing is preliminarily sieved through a 10-18 mesh sieve to remove large-sized impurities and obtain sieved C / C powder, wherein the C / C powder contains short carbon fibers and pyrolytic carbon powder; S2, the C / C powder after the screening in step S1 is screened again through a gradient sieve with a larger mesh size of 18~200 mesh. After screening, short carbon fibers and pyrolytic carbon powder are obtained. The short carbon fibers include two types: bare ordinary fibers and petal-shaped pyrolytic carbon layer coated fibers. S3, the C / C powder after the screening in step S2 is screened again through a gradient sieve with a larger mesh size of 300 mesh, and after screening, short carbon fibers and pyrolytic carbon powder are obtained. S4, the sieved short carbon fibers and pyrolytic carbon powder are uniformly dispersed and mixed with phenolic resin, industrial silicon powder and silicon carbide powder, etc. S5, fill the uniformly dispersed powder into a mold and press it into a fiber-reinforced resin block; S6, the fiber-reinforced resin block obtained after molding is subjected to a one-step continuous carbonization heat treatment and ceramicization heat treatment to obtain C / C SiC composite materials.

[0011] Preferably, the mixed powder comprises, by volume percentage, 5% to 20% short carbon fibers, 25% to 55% pyrolytic carbon powder, 10% to 30% phenolic resin, 10% to 30% silicon powder and 5% to 10% SiC powder.

[0012] Preferably, the process parameters during the pressing process are: molding temperature 150~230℃, molding pressure 5~20MPa, and molding time 20~60min.

[0013] Preferably, the one-step continuous carbonization and ceramization heat treatment is carried out under an argon atmosphere, with the carrier gas flow rate controlled at 40~80 ml / min.

[0014] Preferably, the temperature parameters for the one-step continuous carbonization and ceramization heat treatment are as follows: starting from room temperature, heat to 900~1100℃ and hold for 2~6 hours, then heat to 1500~1800℃ and hold for 2~6 hours, then cool to 300℃ and cool to room temperature with the furnace.

[0015] Preferably, the obtained C / C The density of the SiC composite material is 2.020 ± 0.017 g / cm³. 3 The bending strength is 41.61±1.24 MPa, the compressive strength is 126.71±1.48 MPa, the coefficient of friction is 0.507±0.017, and the wear rate is (1.60±0.33)×10⁻⁶. -14 m 3 N -1 m -1 .

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste. First, a multi-stage sieving process effectively separates short carbon fibers and pyrolytic carbon powder. Because the carbon fibers in the C / C powder are coated with a pyrolytic carbon layer, the characteristics of short fibers being prone to aggregation and difficult to disperse are greatly overcome. Simultaneously, the coating of the pyrolytic carbon layer can prevent the fibers from being eroded by silicon during the silicon-carbon reaction, thereby protecting the mechanical properties and reinforcing effect of the carbon fibers from damage. Then, the screened short carbon fibers and pyrolytic carbon powder are mixed with phenolic resin, industrial silicon powder, and SiC powder, followed by compression molding and a one-step continuous carbonization and ceramic heat treatment to obtain C / C-SiC composite materials. The entire process of preparing SiC composite materials is relatively short (only about 24 hours), and it can produce C / C composites with excellent properties. SiC composite materials. The innovative process of this invention can, on the one hand, produce C / C-SiC composite materials with good mechanical and tribological properties simply, quickly, and at low cost; on the other hand, it successfully realizes the high-value utilization of C / C powder through molding-in-situ reaction, thus effectively solving the environmental pollution and resource waste problems caused by C / C composite material processing waste in existing technologies.

[0017] Furthermore, the C / C-SiC composite material prepared by the method of this invention exhibits excellent properties; its density, as tested, is 2.020 ± 0.017 g / cm³. 3 The bending strength is 41.61±1.24 MPa, the compressive strength is 126.71±1.48 MPa, the coefficient of friction is 0.507±0.017, and the wear rate is (1.60±0.33)×10. -14 m 3 N -1 m -1 . Attached Figure Description

[0018] Figure 1 Figures a) to h) are SEM images of C / C powder; where Figures a) to h) are SEM images after sieving through sieves of different mesh sizes.

[0019] Figure 2 A flowchart illustrating a method for preparing C / C-SiC composite materials through multi-stage recycling of waste materials from carbon / carbon composite material processing.

[0020] Figure 3 The images are polarized light micrographs and SEM images of C / C-SiC composite materials; where a) is a low-magnification polarized light micrograph; b) is a high-magnification polarized light micrograph; c) is a low-magnification SEM image; and d) is a high-magnification SEM image.

[0021] Figure 4 X-ray diffraction pattern of C / C-SiC composite material.

[0022] Figure 5 The graphs show the mechanical properties of C / C-SiC composite materials; where a) is the bending load-displacement curve and b) is the compressive load-displacement curve.

[0023] Figure 6 SEM images of the bending and compressive fracture sections of C / C-SiC composite materials; where a) and b) are SEM images of the bending fracture section; and c) and d) are SEM images of the compressive fracture section.

[0024] Figure 7 The diagram shows the tribological properties of C / C-SiC composite materials.

[0025] Figure 8 SEM images of the surface of C / C-SiC composite material after friction; where a) and b) are low-magnification SEM images; c) and d) are high-magnification SEM images. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0028] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under standard conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications in the art, unless otherwise stated.

[0029] This invention, through detailed analysis of the high strength and high modulus mechanical properties of short carbon fibers in C / C powder and the tribological properties of pyrolytic carbon lubrication and wear resistance, provides a simple, rapid, and low-cost molding-in-situ reaction method for preparing C / C-SiC composite materials, in order to solve the environmental pollution and resource waste problems caused by C / C composite material processing waste in existing production processes.

[0030] See Figure 2 This invention first obtains C / C powder free of large-sized impurities through initial sieving, then separates short carbon fibers and pyrolytic carbon powder through two sieving processes. These are then mixed uniformly with phenolic resin, industrial silicon powder, SiC powder, etc., at appropriate volume fractions, and fiber-reinforced resin blocks are obtained through a molding process. Next, the molded fiber-reinforced resin blocks undergo a one-step continuous carbonization heat treatment and ceramicization heat treatment to obtain C / C... SiC composite materials.

[0031] Specifically, a method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste includes the following steps: S1, the carbon / carbon composite material processing waste, namely carbon / carbon composite material residue, abbreviated as C / C powder, is preliminarily sieved through a screen to remove large-sized impurities and obtain sieved C / C powder, wherein the C / C powder contains short carbon fibers and pyrolytic carbon powder; S2, the C / C powder after the screening in step S1 is screened again through a gradient sieve with a larger mesh size. After screening, short carbon fibers and pyrolytic carbon powder are obtained. The short carbon fibers include two types: bare ordinary fibers and petal-shaped pyrolytic carbon layer coated fibers. S3, the C / C powder after the screening in step S2 is screened again through a gradient sieve with a larger mesh size, and the sieved powder is classified to obtain short carbon fibers and pyrolytic carbon powder. S4, the sieved short carbon fibers and pyrolytic carbon powder are uniformly dispersed and mixed with phenolic resin, industrial silicon powder and silicon carbide powder, etc. S5, fill the uniformly dispersed powder into a mold and press it into a fiber-reinforced resin block; S6, the fiber-reinforced resin block obtained after molding is subjected to a one-step continuous carbonization heat treatment and ceramicization heat treatment to obtain C / C SiC composite materials.

[0032] In some embodiments of the present invention, in S1, the C / C powder is waste generated during the processing of carbon / carbon composite materials, which contains short carbon fibers and pyrolytic carbon powder. The sieve used is 10-18 mesh, and the sieving process in S1 removes larger impurities.

[0033] In some embodiments of the present invention, in S2, the short carbon fibers and pyrolytic carbon powder in the C / C powder are initially separated by a second sieving process, wherein the sieve used in the sieving process is 18 to 200 mesh.

[0034] In some embodiments of the present invention, in S3, the short carbon fibers and pyrolytic carbon powder in the C / C powder are completely separated by three sieving processes, wherein the sieve used in the sieving process is 300 mesh.

[0035] In some embodiments of the present invention, in S4, the raw materials are 5-20% short carbon fibers, 25-55% pyrolytic carbon powder, 10-30% silicon powder, 10-30% phenolic resin, and 5-10% silicon carbide powder by volume percentage, and the sum of the above volume percentages is 100%.

[0036] In some embodiments of the present invention, in step S5, the molding temperature is 150~230℃, the molding pressure is 5~20MPa, and the molding time is 20~60min.

[0037] In some embodiments of the present invention, in step S6, the carrier gas atmosphere is Ar, the carrier gas flow rate is 40~80 ml / min, the temperature is raised to 900~1100℃ and held for 2~6 h, then the temperature is raised to 1500~1800℃ and held for 2~6 h, and then the temperature is lowered to 300℃ and cooled to room temperature with the furnace.

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Example 1 A method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste includes the following steps: Step 1: Remove impurities from C / C powder The C / C powder is initially sieved to remove large-sized impurities, and the sieved C / C powder is obtained. The C / C powder contains short carbon fibers and pyrolytic carbon powder. The sieve used in the sieving process is 10 to 18 mesh. Step 2: Initial separation of C / C powder The C / C powder after step 1 is sieved again using a high-mesh sieve. The sieve used in the sieving process is 18 to 200 mesh. After sieving, short carbon fibers and pyrolytic carbon powder are obtained. The short carbon fibers include two types: bare ordinary fibers and petal-shaped pyrolytic carbon layer coated fibers. Step 3: C / C powder re-separation The C / C powder after step 2 is sieved again using a sieve with a higher mesh size. The sieve used in the sieving process is 300 mesh. After sieving, short carbon fibers and pyrolytic carbon powder are obtained. Step 4: Mixing raw materials The sieved short carbon fibers and pyrolytic carbon powder are uniformly dispersed and mixed with phenolic resin, industrial silicon powder, and SiC powder. The raw materials are composed of 20% short carbon fibers, 30% pyrolytic carbon powder, 20% silicon powder, 20% phenolic resin, and 10% silicon carbide powder by volume, and the sum of the above volume percentages is 100%. Step 5: Molding The uniformly dispersed powder was filled into a mold and molded into a fiber-reinforced resin block. The molding temperature was 150℃, the molding pressure was 5MPa, and the molding time was 20min. Step 6: Carbonization and Ceramization The fiber-reinforced resin block obtained after molding is subjected to a one-step continuous carbonization heat treatment and ceramicization heat treatment to obtain C / C The SiC composite material was heated to 900℃ and held for 2 hours, then heated to 1500℃ and held for 2 hours. After cooling to 300℃, it was cooled to room temperature in the furnace.

[0039] Example 2 A method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste includes the following steps: Step 1: Remove impurities from C / C powder The C / C powder is initially sieved to remove large-sized impurities, and the sieved C / C powder is obtained. The C / C powder contains short carbon fibers and pyrolytic carbon powder. The sieve used in the sieving process is 10 to 18 mesh. Step 2: Initial separation of C / C powder The C / C powder after step 1 is sieved again using a high-mesh sieve. The sieve used in the sieving process is 18 to 200 mesh. After sieving, short carbon fibers and pyrolytic carbon powder are obtained. The short carbon fibers include two types: bare ordinary fibers and petal-shaped pyrolytic carbon layer coated fibers. Step 3: C / C powder re-separation The C / C powder after step 2 is sieved again using a sieve with a higher mesh size. The sieve used in the sieving process is 300 mesh. After sieving, short carbon fibers and pyrolytic carbon powder are obtained. Step 4: Mixing raw materials The sieved short carbon fibers and pyrolytic carbon powder are uniformly dispersed and mixed with phenolic resin and industrial silicon powder. The raw materials are composed of 15% short carbon fibers, 40% pyrolytic carbon powder, 25% silicon powder, 15% phenolic resin, and 10% silicon carbide powder by volume, and the sum of the above volume percentages is 100%. Step 5: Molding The uniformly dispersed powder was filled into a mold and molded into a fiber-reinforced resin block. The molding temperature was 160℃, the molding pressure was 20MPa, and the molding time was 40min. Step 6: Carbonization and Ceramization The fiber-reinforced resin block obtained after molding is subjected to a one-step continuous carbonization heat treatment and ceramicization heat treatment to obtain C / C The SiC composite material was heated to 1000℃ and held for 2 hours, then heated to 1600℃ and held for 2 hours. After cooling to 300℃, it was cooled to room temperature in the furnace.

[0040] Example 3 A method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste includes the following steps: Step 1: Remove impurities from C / C powder The C / C powder is initially sieved to remove large-sized impurities, and the sieved C / C powder is obtained. The C / C powder contains short carbon fibers and pyrolytic carbon powder. The sieve used in the sieving process is 10 to 18 mesh. Step 2: Initial separation of C / C powder The C / C powder after step 1 is sieved again using a high-mesh sieve. The sieve used in the sieving process is 18 to 200 mesh. After sieving, short carbon fibers and pyrolytic carbon powder are obtained. The short carbon fibers include two types: bare ordinary fibers and petal-shaped pyrolytic carbon layer coated fibers. Step 3: C / C powder re-separation The C / C powder after step 2 is sieved again using a sieve with a higher mesh size. The sieve used in the sieving process is 300 mesh. After sieving, short carbon fibers and pyrolytic carbon powder are obtained. Step 4: Mixing raw materials The sieved short carbon fibers and pyrolytic carbon powder are uniformly dispersed and mixed with phenolic resin and industrial silicon powder. The raw materials are composed of 20% short carbon fibers, 25% pyrolytic carbon powder, 25% silicon powder, 20% phenolic resin, and 10% silicon carbide powder by volume, and the sum of the above volume percentages is 100%. Step 5: Molding The uniformly dispersed powder was filled into a mold and molded into a fiber-reinforced resin block. The molding temperature was 180℃, the molding pressure was 10MPa, and the molding time was 30min. Step 6: Carbonization and Ceramization The fiber-reinforced resin block obtained after molding is subjected to a one-step continuous carbonization heat treatment and ceramicization heat treatment to obtain C / C The SiC composite material was heated to 1000℃ and held for 2 hours, then heated to 1600℃ and held for 2 hours. After cooling to 300℃, it was cooled to room temperature in the furnace.

[0041] Example 4 A method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste includes the following steps: Step 1: Remove impurities from C / C powder The C / C powder is initially sieved to remove large-sized impurities, and the sieved C / C powder is obtained. The C / C powder contains short carbon fibers and pyrolytic carbon powder. The sieve used in the sieving process is 10 to 18 mesh. Step 2: Initial separation of C / C powder The C / C powder after step 1 is sieved again using a high-mesh sieve. The sieve used in the sieving process is 18 to 200 mesh. After sieving, short carbon fibers and pyrolytic carbon powder are obtained. The short carbon fibers include two types: bare ordinary fibers and petal-shaped pyrolytic carbon layer coated fibers. Step 3: C / C powder re-separation The C / C powder after step 2 is sieved again using a sieve with a higher mesh size. The sieve used in the sieving process is 300 mesh. After sieving, short carbon fibers and pyrolytic carbon powder are obtained. Step 4: Mixing raw materials The sieved short carbon fibers and pyrolytic carbon powder are uniformly dispersed and mixed with phenolic resin and industrial silicon powder. The raw materials are composed of 10% short carbon fibers, 50% pyrolytic carbon powder, 15% silicon powder, 15% phenolic resin, and 10% silicon carbide powder by volume percentage, and the sum of the above volume percentages is 100%. Step 5: Molding The uniformly dispersed powder was filled into a mold and molded into a fiber-reinforced resin block. The molding temperature was 200℃, the molding pressure was 15MPa, and the molding time was 60min. Step 6: Carbonization and Ceramization The fiber-reinforced resin block obtained after molding is subjected to a one-step continuous carbonization heat treatment and ceramicization heat treatment to obtain C / C The SiC composite material was heated to 1100℃ and held for 4 hours, then heated to 1800℃ and held for 4 hours. After cooling to 300℃, it was cooled to room temperature in the furnace.

[0042] Example 5 A method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste includes the following steps: Step 1: Remove impurities from C / C powder The C / C powder is initially sieved to remove large-sized impurities, and the sieved C / C powder is obtained. The C / C powder contains short carbon fibers and pyrolytic carbon powder. The sieve used in the sieving process is 10 to 18 mesh. Step 2: Initial separation of C / C powder The C / C powder after step 1 is sieved again using a high-mesh sieve. The sieve used in the sieving process is 18 to 200 mesh. After sieving, short carbon fibers and pyrolytic carbon powder are obtained. The short carbon fibers include two types: bare ordinary fibers and petal-shaped pyrolytic carbon layer coated fibers. Step 3: C / C powder re-separation The C / C powder after step 2 is sieved again using a sieve with a higher mesh size. The sieve used in the sieving process is 300 mesh. After sieving, short carbon fibers and pyrolytic carbon powder are obtained. Step 4: Mixing raw materials The sieved short carbon fibers and pyrolytic carbon powder are uniformly dispersed and mixed with phenolic resin and industrial silicon powder. The raw materials are composed of 15% short carbon fibers, 35% pyrolytic carbon powder, 20% silicon powder, 25% phenolic resin, and 5% silicon carbide powder by volume, and the sum of the above volume percentages is 100%. Step 5: Molding The uniformly dispersed powder was filled into a mold and molded into a fiber-reinforced resin block. The molding temperature was 180℃, the molding pressure was 10MPa, and the molding time was 30min. Step 6: Carbonization and Ceramization The fiber-reinforced resin block obtained after molding is subjected to a one-step continuous carbonization heat treatment and ceramicization heat treatment to obtain C / C The SiC composite material was heated to 900℃ and held for 6 hours, then heated to 1700℃ and held for 2 hours. After cooling to 300℃, it was cooled to room temperature in the furnace.

[0043] Figure 1 SEM images of C / C powder, from Figure 1 It can be seen that C / C powder is mainly composed of short carbon fibers and pyrolytic carbon powder. The short carbon fibers include two types: exposed fibers and fibers wrapped in petal-shaped pyrolytic carbon layers. After sieving, the short carbon fibers and pyrolytic carbon powder can be separated.

[0044] Figure 2 This is a flowchart of a method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste. The main preparation process of C / C-SiC composite materials includes sieving of C / C composite material processing waste, mixing and molding of different powders, and subsequent carbonization and ceramization treatment.

[0045] Figure 3 These are polarized light micrographs and SEM images of the C / C-SiC composite material prepared in Example 1. Figure 3 It can be seen that SiC is uniformly dispersed inside the C / C-SiC composite material, the material is dense and has low porosity.

[0046] Figure 4The X-ray diffraction pattern of the C / C-SiC composite material prepared in Example 2 is shown below. Figure 4 It can be seen that it contains only two phases: SiC and C.

[0047] Figure 5 The mechanical property test diagram of the C / C-SiC composite material prepared in Example 3 shows that its flexural strength is 41.61±1.24MPa and its compressive strength is 126.71±1.48MPa.

[0048] Figure 6 The images show SEM images of the bending and compression fracture sections of the C / C-SiC composite material prepared in Example 4. During bending, due to the coating of the pyrolytic carbon layer, there is good interfacial bonding, exhibiting fiber pull-out (as shown in figures a) and b). During compression, the matrix transfers the load to the fibers, causing fiber breakage. Figure 6 (as shown in c) and d).

[0049] Figure 7 The tribological property test diagram of the C / C-SiC composite material prepared in Example 3 shows a friction coefficient of 0.507±0.017 and a wear rate of (1.60±0.33)×10⁻⁶. -14 m 3 N -1 m -1 .

[0050] Figure 8 The image shows the surface SEM image of the C / C-SiC composite material prepared in Example 5 after friction. After friction, a continuous and stable silicon-carbon dispersed embedded friction film is formed, accompanied by the generation of hard wear particles.

[0051] Meanwhile, the tribological properties of the materials prepared in the above embodiments are shown in Table 1 below: Table 1

[0052] In summary, this invention achieves high-value recycling of C / C processing waste. The process is simple, low-cost, and easy to operate, solving the resource waste and environmental pollution problems caused by existing waste treatment methods. The prepared C / C-SiC composite material exhibits excellent performance and can be widely used in aerospace, high-end manufacturing, and other fields. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing C / C-SiC composite materials through multi-stage recycling of waste from carbon / carbon composite material processing, characterized in that, include: Multi-stage sieving was performed on waste materials from carbon / carbon composite material processing to screen out short carbon fibers and pyrolytic carbon powder. The short carbon fibers, pyrolytic carbon powder, phenolic resin, industrial silicon powder, and SiC powder were then mixed using a molding process to obtain a mixed powder. This mixed powder was then pressed into fiber-reinforced resin blocks, which were subsequently subjected to a one-step continuous carbonization and ceramic heat treatment to obtain C / C composites. SiC composite materials.

2. The method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste according to claim 1, characterized in that, The mesh size of the sieve increases progressively with each stage of the multi-stage sieving process.

3. The method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste according to claim 2, characterized in that, The multi-stage sieving includes three stages of sieving.

4. The method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste according to claim 2, characterized in that, The first-stage sieve should be 10-18 mesh, the second-stage sieve should be 18-200 mesh, and the third-stage sieve should be 300 mesh.

5. The method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste according to claim 1, characterized in that, The mixed powder, by volume percentage, includes 5% to 20% short carbon fibers, 25% to 55% pyrolytic carbon powder, 10% to 30% phenolic resin, 10% to 30% industrial silicon powder, and 5% to 10% SiC powder.

6. The method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste according to claim 1, characterized in that, The process parameters during the pressing process are: molding temperature 150~230℃, molding pressure 5~20MPa, and molding time 20~60min.

7. The method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste according to claim 1, characterized in that, The one-step continuous carbonization and ceramization heat treatment is carried out under an argon atmosphere, with the carrier gas flow rate controlled at 40~80 ml / min.

8. The method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste according to claim 1, characterized in that, The temperature parameters for one-step continuous carbonization and ceramization heat treatment are as follows: starting from room temperature, heat to 900~1100℃ and hold for 2~6 hours, then heat to 1500~1800℃ and hold for 2~6 hours, then cool to 300℃ and cool to room temperature with the furnace.

9. The method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste according to claim 1, characterized in that, The obtained C / C The density of the SiC composite material is 2.020 ± 0.017 g / cm³. 3 .

10. The method for preparing C / C-SiC composite materials through multi-stage recycling of carbon / carbon composite material processing waste according to claim 1, characterized in that, The obtained C / C The SiC composite material has a flexural strength of 41.61±1.24 MPa, a compressive strength of 126.71±1.48 MPa, a coefficient of friction of 0.507±0.017, and a wear rate of (1.60±0.33)×10⁻⁶. -14 m 3 N -1 m -1 .

Images