A manufacturing process for ceramic-based composite pipes

Abstract

This invention provides a manufacturing process for ceramic-based composite pipes, relating to the field of ceramic-based composite material preparation technology. The manufacturing process specifically includes the following steps: Step 1: Slurry preparation, mixing polymethylsilane (PMS), silicon carbide powder, and divinylbenzene (DVB), and stirring at a constant temperature for 3-4 hours under an inert atmosphere to ensure uniform dispersion of the components, obtaining an impregnation slurry. The amount of silicon carbide added is 150%-220% of the mass of PMS, and the amount of DVB added is 15%-20% of the mass of PMS. This invention provides a manufacturing process for ceramic-based composite pipes. This process combines fiber-oriented winding molding with precursor ceramicization conversion, achieving integrated pipe forming and densification, effectively solving many defects of existing technologies.

Description

Technical Field

[0001] This invention relates to the field of ceramic matrix composite material preparation technology, specifically to a manufacturing process for ceramic matrix composite pipes. Background Technology

[0002] Ceramic matrix materials, due to their excellent high-temperature resistance, corrosion resistance, and oxidation resistance, are widely used in aerospace, energy, chemical, and nuclear industries, especially in high-temperature fluid transportation pipelines, corrosion-resistant media pipelines, and thermal structural pipe fittings, demonstrating significant application value. However, traditional single ceramic materials suffer from inherent defects such as high brittleness, poor impact resistance, and low fracture toughness. Under the combined effects of internal pressure, temperature gradients, and external loads, they are prone to sudden brittle fracture, making it difficult to meet the safety and reliability requirements of pipe structures and severely restricting their further application in engineering fields.

[0003] To address the aforementioned issues, ceramic matrix composites effectively improve their mechanical properties and failure behavior by introducing fiber reinforcements. Fibers within the matrix can significantly delay crack propagation through mechanisms such as crack deflection, crack bridging, and interfacial slip, thereby enhancing the material's fracture toughness and damage resistance. For ceramic matrix composite pipes, during service, they are subjected to circumferential stress primarily due to internal pressure, accompanied by axial stress and thermal stress, exhibiting distinct anisotropic stress characteristics. By employing directional laying of fiber cloth or fiber bundles, circumferential reinforcement, axial reinforcement, or multi-angle reinforcement can be achieved, thereby improving the pipe's pressure-bearing capacity, thermal shock resistance, and overall structural stability, making it more suitable for complex working environments.

[0004] Currently, the main methods for preparing ceramic-based composite pipes include chemical vapor infiltration (CVI) and precursor impregnation pyrolysis (PIP). While CVI can yield materials with high density, it suffers from complex equipment, long manufacturing cycles, and high costs, hindering its engineering application. PIP is relatively simple, but due to the significant volume shrinkage of the precursor during pyrolysis, multiple impregnation-pyrolysis cycles are typically required to improve density, resulting in long preparation cycles, low efficiency, and the potential for introducing new defects during repeated processing.

[0005] Furthermore, in tubular structures, due to their limited wall thickness and closed or semi-closed structure, the gases generated during the pyrolysis of the precursor are not easily discharged in a timely manner, making it easier for defects such as pores, air holes, and even cracks to form inside, thus affecting the material's density and mechanical properties. At the same time, traditional processes often involve preforming the material before impregnation, which limits the uniformity of fiber reinforcement distribution. This is especially true in tubular structures, where continuous and uniform layup control is difficult to achieve, leading to uneven local performance and affecting the overall load-bearing capacity and service life.

[0006] Therefore, considering the structural characteristics and service requirements of ceramic matrix composite pipes, it is urgent to develop a simple, efficient, and effective preparation method that can achieve uniform fiber orientation and improve ceramic yield. This method would reduce porosity and crack defects caused by precursor pyrolysis shrinkage, improve material density and mechanical properties, and thus obtain high-strength, high-reliability ceramic matrix composite pipes to meet their engineering application requirements under high temperature, high pressure and complex environmental conditions. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a manufacturing process for ceramic-based composite pipes. Addressing the problems of complex equipment, long preparation cycles, high costs, defects caused by precursor pyrolysis shrinkage, uneven fiber reinforcement distribution, and insufficient mechanical properties and structural stability in existing ceramic-based composite pipe manufacturing processes, this invention provides a new manufacturing process for ceramic-based composite pipes. This process combines fiber-oriented winding molding with precursor ceramicization conversion, achieving integrated pipe forming and densification, effectively solving many of the shortcomings of existing technologies.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A manufacturing process for a ceramic-based composite pipe, the manufacturing process specifically including the following steps: Step 1: Slurry preparation; Polymethylsilane (PMS), silicon carbide powder, and divinylbenzene (DVB) are mixed and stirred at a constant temperature for 3–4 hours under an inert atmosphere to ensure uniform dispersion of the components, thereby obtaining an impregnation slurry. The amount of silicon carbide powder added is 150%–220% of the mass of PMS, and the amount of DVB added is 15%–20% of the mass of PMS. Step 2: Impregnation and winding molding; The fiber cloth or fiber bundle is impregnated in the impregnation slurry prepared in step 1, and continuously wound around the outer surface of the tubular inner mold while impregnated. The fiber arrangement is controlled by adjusting the winding speed and the swing mechanism, so that the fibers are evenly distributed on the surface of the inner mold to form a tubular preform. Step 3: Curing treatment; The wound tubular preform, together with the inner mold, is placed in an inert atmosphere and kept at 150°C for 2-4 hours to allow the slurry to undergo a cross-linking and curing reaction. Step 4: Demolding; Cool the cured tubular preform to room temperature and remove the inner mold to obtain the tubular blank. Step 5: Sintering and shaping; The tubular preform is placed in a high-temperature furnace and sintered at 1200°C in stages under an inert atmosphere to complete the transformation of the precursor into a ceramic matrix. After the high-temperature furnace cools naturally to room temperature, the ceramic matrix composite tube is obtained.

[0009] Furthermore, the temperature range for constant-temperature stirring during the slurry preparation process in step 1 is limited to 20℃~25℃.

[0010] Furthermore, in step 1, the particle size of the silicon carbide powder in the slurry preparation is 0.1 μm to 10 μm.

[0011] Furthermore, in step 2, during the impregnation and winding process, the fiber cloth or fiber bundle is selected from any one of carbon fiber, silicon carbide fiber, or oxide fiber.

[0012] Furthermore, in the process of impregnation and winding in step 2, the winding method is either circumferential winding or spiral winding.

[0013] Furthermore, during the impregnation and winding process in step 2, the winding speed is 20~50 r / min.

[0014] Furthermore, the curing process in step 3 needs to be carried out under a nitrogen atmosphere.

[0015] Furthermore, the staged heating method during the sintering process in step 5 is specifically as follows: The first stage involves raising the temperature from room temperature (20°C) to 150°C within 50 minutes; the second stage involves raising the temperature from 150°C to 700°C within 280 minutes; and the third stage involves raising the temperature from 700°C to 1200°C within 100 minutes.

[0016] Furthermore, during the sintering process in step 5, a heat preservation process is provided in the 700℃ to 1200℃ range.

[0017] Furthermore, the prepared ceramic-based pipe is a silicon carbide ceramic-based composite material pipe.

[0018] This invention provides a manufacturing process for ceramic-based composite pipes. It offers the following advantages: 1. This invention provides a manufacturing process for ceramic-based composite pipes. This process combines fiber impregnation, winding molding and precursor ceramicization, realizing the integrated preparation of ceramic-based composite pipes by molding and densification. It eliminates the need for multiple impregnation-pyrolysis cycles, significantly shortens the preparation cycle, simplifies the process, reduces the preparation cost, and is suitable for large-scale industrial production.

[0019] 2. This invention provides a manufacturing process for ceramic-based composite pipes. This process effectively alleviates the volume shrinkage problem during the pyrolysis of the precursor by introducing a high proportion of silicon carbide powder filler into the PMS precursor and using DVB crosslinking agent, significantly improving the ceramic yield, reducing defects such as pores and cracks caused by pyrolysis shrinkage, and improving the density and structural integrity of the pipe.

[0020] 3. This invention provides a manufacturing process for ceramic-based composite pipes. This process employs a simultaneous impregnation and winding molding method, allowing the fibers to complete directional winding while impregnated with slurry. This ensures sufficient wetting of the fibers and slurry, improves the interfacial bonding performance between the fibers and the matrix, and enables precise control of winding parameters to achieve uniform directional distribution of the fibers in the circumferential and axial directions of the pipe. This matches the stress characteristics of the pipe, significantly improving its pressure-bearing capacity, fracture toughness, and thermal shock resistance. It also possesses excellent high-temperature resistance, corrosion resistance, oxidation resistance, and good mechanical properties, and can be widely used in high-temperature fluid transportation, corrosion-resistant media pipelines, and thermal structural pipe fittings in aerospace, energy and chemical, and nuclear industries, showing broad engineering application prospects. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the manufacturing process of the ceramic-based composite pipe of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention. Example 1:

[0023] like Figure 1 As shown in the figure, an embodiment of the present invention provides a manufacturing process for a ceramic-based composite pipe, the manufacturing process specifically including the following steps: Step 1: Slurry preparation; Polymethylsilane (PMS), silicon carbide powder, and divinylbenzene (DVB) are mixed and stirred at a constant temperature for 3–4 hours under an inert atmosphere to ensure uniform dispersion of the components, thereby obtaining an impregnation slurry. The amount of silicon carbide powder added is 150%–220% of the mass of PMS, and the amount of DVB added is 15%–20% of the mass of PMS. Step 2: Impregnation and winding molding; The fiber cloth or fiber bundle is impregnated in the impregnation slurry prepared in step 1, and continuously wound around the outer surface of the tubular inner mold while impregnated. The fiber arrangement is controlled by adjusting the winding speed and the swing mechanism, so that the fibers are evenly distributed on the surface of the inner mold to form a tubular preform. Step 3: Curing treatment; The wound tubular preform, together with the inner mold, is placed in an inert atmosphere and kept at 150°C for 2-4 hours to allow the slurry to undergo a cross-linking and curing reaction. Step 4: Demolding; Cool the cured tubular preform to room temperature and remove the inner mold to obtain the tubular blank. Step 5: Sintering and shaping; The tubular preform is placed in a high-temperature furnace and sintered at 1200°C in stages under an inert atmosphere to complete the transformation of the precursor into a ceramic matrix. After the high-temperature furnace cools naturally to room temperature, the ceramic matrix composite tube is obtained.

[0024] The temperature range for constant temperature stirring during the slurry preparation process in step 1 is limited to 20℃~25℃. In step 1, the particle size of the silicon carbide powder is 0.1 μm to 10 μm. During the impregnation and winding process in step 2, the fiber cloth or fiber bundle is selected from any one of carbon fiber, silicon carbide fiber or oxide fiber. In step 2, the winding method during the impregnation and winding process is either circumferential winding or spiral winding. During the impregnation and winding process in step 2, the winding speed is 20~50 r / min; The curing process in step 3 needs to be carried out under a nitrogen atmosphere. The specific method of staged heating during the sintering process in step 5 is as follows: The first stage involves raising the temperature from room temperature (20°C) to 150°C within 50 minutes; the second stage involves raising the temperature from 150°C to 700°C within 280 minutes; and the third stage involves raising the temperature from 700°C to 1200°C within 100 minutes. During the sintering process in step 5, a heat preservation process is provided in the 700℃ to 1200℃ range. The prepared ceramic-based pipe is a silicon carbide ceramic-based composite material pipe.

[0025] The following points should be noted in this article: 1. The accompanying drawings of the embodiments disclosed herein only relate to the structures involved in the embodiments disclosed herein; other structures can be referred to in general design.

[0026] 2. Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0027] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations 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. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A manufacturing process for a ceramic-based composite pipe, characterized in that: The manufacturing process specifically includes the following steps: Step 1: Slurry preparation; Polymethylsilane (PMS), silicon carbide powder, and divinylbenzene (DVB) are mixed and stirred at a constant temperature for 3–4 hours under an inert atmosphere to ensure uniform dispersion of the components, thereby obtaining an impregnation slurry. The amount of silicon carbide powder added is 150%–220% of the mass of PMS, and the amount of DVB added is 15%–20% of the mass of PMS. Step 2: Impregnation and winding molding; The fiber cloth or fiber bundle is impregnated in the impregnation slurry prepared in step 1, and continuously wound around the outer surface of the tubular inner mold while impregnated. The fiber arrangement is controlled by adjusting the winding speed and the swing mechanism, so that the fibers are evenly distributed on the surface of the inner mold to form a tubular preform. Step 3: Curing treatment; The wound tubular preform, together with the inner mold, is placed in an inert atmosphere and kept at 150°C for 2-4 hours to allow the slurry to undergo a cross-linking and curing reaction. Step 4: Demolding; Cool the cured tubular preform to room temperature and remove the inner mold to obtain the tubular blank. Step 5: Sintering and shaping; The tubular preform is placed in a high-temperature furnace and sintered at 1200°C in stages under an inert atmosphere to complete the transformation of the precursor into a ceramic matrix. After the high-temperature furnace cools naturally to room temperature, the ceramic matrix composite tube is obtained.

2. The manufacturing process of a ceramic-based composite pipe according to claim 1, characterized in that: The temperature range for constant temperature stirring during the slurry preparation process in step 1 is limited to 20℃~25℃.

3. The manufacturing process of a ceramic-based composite pipe according to claim 1, characterized in that: In step 1, the particle size of the silicon carbide powder in the slurry preparation is 0.1 μm to 10 μm.

4. The manufacturing process of a ceramic-based composite pipe according to claim 1, characterized in that: In step 2, during the impregnation and winding process, the fiber cloth or fiber bundle is selected from any one of carbon fiber, silicon carbide fiber or oxide fiber.

5. The manufacturing process of a ceramic-based composite pipe according to claim 1, characterized in that: In step 2, the winding method during the impregnation and winding process is either circumferential winding or spiral winding.

6. The manufacturing process of a ceramic-based composite pipe according to claim 1, characterized in that: The winding speed during the impregnation and winding process in step 2 is 20~50 r / min.

7. The manufacturing process of a ceramic-based composite pipe according to claim 1, characterized in that: The curing process in step 3 needs to be carried out under a nitrogen atmosphere.

8. The manufacturing process of a ceramic-based composite pipe according to claim 1, characterized in that: The specific method of staged heating during the sintering process in step 5 is as follows: The first stage involves raising the temperature from room temperature (20°C) to 150°C within 50 minutes; the second stage involves raising the temperature from 150°C to 700°C within 280 minutes; and the third stage involves raising the temperature from 700°C to 1200°C within 100 minutes.

9. The manufacturing process of a ceramic-based composite pipe according to claim 1, characterized in that: During the sintering process in step 5, a heat preservation process is provided in the range of 700℃ to 1200℃.

10. The manufacturing process of a ceramic-based composite pipe according to claim 1, characterized in that: The prepared ceramic-based pipe is a silicon carbide ceramic-based composite material pipe.

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