A kind of C / SiC ceramic matrix composite preform and its preparation method

Abstract

The application relates to a ceramic matrix composite material, in particular to a C / SiC ceramic matrix composite material preform and a preparation method thereof, which are used to solve the problems that the preparation period of the C / SiC ceramic matrix composite material prepared by CVI is long, the deposition is dependent on diffusion, the porosity of the finished product is relatively large, and it is difficult to manufacture a finished product with a large thickness. The C / SiC ceramic matrix composite material preform is provided with a plurality of air hole channels in the matrix, the air hole rate of the preform is increased, the gaseous precursor can fully diffuse and contact the fiber tows in the inner part of the preform, the rapid conversion of the C / SiC matrix is improved, the reaction depth of the C / SiC matrix is effectively improved, and a thicker finished product can be prepared, and the preparation period of the finished product can be effectively shortened.

Description

Technical Field

[0001] This invention relates to ceramic matrix composites, and more specifically to a preform of a C / SiC ceramic matrix composite and its preparation method. Background Technology

[0002] Ceramic matrix composites (CMCs) are multiphase materials in which a second phase material is introduced into a ceramic matrix to enhance its strength and toughness. They are also known as multiphase composite ceramics or diphase ceramics. CMCs are a new type of ceramic material that has gradually developed since the 1980s. They include fiber (or whisker) toughened (or reinforced) ceramic matrix composites, heterogeneous particle dispersion-strengthened diphase ceramics, in-situ grown ceramic composites, graded functional composites, and nano-ceramic composites. CMCs possess characteristics such as high temperature resistance, wear resistance, high-temperature creep resistance, low thermal conductivity, low coefficient of thermal expansion, chemical corrosion resistance, high strength, and high hardness, making them ideal high-temperature structural materials. In light of this, many countries have conducted research on ceramic matrix composites, greatly expanding their application fields and developing various new preparation technologies.

[0003] In addition to possessing a series of excellent properties such as high temperature resistance, high specific strength, high specific modulus, high thermal conductivity, and low coefficient of thermal expansion, C / SiC ceramic matrix composites also exhibit high matrix density, good thermal shock resistance, ablation resistance, fatigue resistance, and creep resistance. They demonstrate superior high-temperature thermodynamics and microstructural stability, making them a novel lightweight composite material that combines strong structural load-bearing capacity with resistance to harsh environments. They have broad application prospects in high-temperature thermal structural components such as thermal protection systems for aerospace vehicles, aero engines, rocket engines, and high-performance braking systems. The use of this type of material can improve the mechanical properties and high-temperature resistance of structural components, while reducing system weight and improving system safety and reliability.

[0004] With the continuous development of science and technology and the continuous improvement of preparation methods, the main preparation processes of C / SiC ceramic matrix composites are: chemical vapor deposition / infiltration (CVD / CVI), precursor impregnation pyrolysis (PIP), reactive melt infiltration (M1), and slurry impregnation hot pressing (HP).

[0005] The basic process of CVI is as follows: a SiC fiber preform is placed in a reaction chamber, and a gaseous SiC precursor is introduced. After the gaseous SiC precursor reaches the preform, it diffuses into the SiC fibers inside the preform and then undergoes a chemical reaction to produce the SiC matrix.

[0006] The CVI process requires relatively low temperatures and causes minimal damage to SiC fibers. The pores in the braid allow gas to pass through, which is beneficial for the diffusion of gaseous SiC precursors and facilitates the fabrication of complex shapes. Gas parameters are controllable throughout the process, allowing for flexible control over the composition and properties of the final product. However, CVI has a long preparation cycle, and because its deposition relies on diffusion, it has relatively high porosity, making it difficult to manufacture thicker products. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of C / SiC ceramic matrix composite material preparation using CVI, which has a long cycle and relies on diffusion for deposition, resulting in a relatively large porosity in the finished product and making it difficult to manufacture thick finished products. The invention provides a preform of C / SiC ceramic matrix composite material and its preparation method.

[0008] To address the shortcomings of the existing technology, the present invention provides the following technical solution:

[0009] A preform of a C / SiC ceramic matrix composite material includes a matrix formed by stacking N layers of carbon fiber nonwoven fabric, characterized in that it also includes multiple pore channels disposed within the matrix, wherein the multiple pore channels are arranged according to method one or method two; N is a positive integer greater than or equal to 3.

[0010] Method 1 involves arranging multiple air pore channels in a row-column matrix manner, with each air pore channel positioned along the stacking direction of N layers of carbon fiber nonwoven fabric and penetrating each layer of carbon fiber nonwoven fabric in sequence.

[0011] The second method involves N layers of carbon fiber nonwoven fabric comprising M stacking units. Each stacking unit includes a lower layer, a middle layer, and an upper layer arranged sequentially from bottom to top. A pore channel layer is provided between the lower layer and the middle layer, and between the middle layer and the upper layer. The pore channel layer includes multiple parallel pore channels. The lower layer, the middle layer, and the upper layer are all composed of at least one layer of carbon fiber nonwoven fabric. M is a positive integer greater than or equal to 1.

[0012] Furthermore, the odd-numbered layers of carbon fiber nonwoven fabric in the matrix have the same weaving structure, the even-numbered layers of carbon fiber nonwoven fabric have the same weaving structure, and the odd-numbered layers of carbon fiber nonwoven fabric have a different weaving structure than the even-numbered layers of carbon fiber nonwoven fabric.

[0013] Furthermore, the odd-numbered layers of carbon fiber nonwoven fabric in the matrix have a weave structure of 0 / 90°, and the even-numbered layers of carbon fiber nonwoven fabric have a weave structure of 90 / 0°; or the odd-numbered layers of carbon fiber nonwoven fabric in the matrix have a weave structure of 90 / 0°, and the even-numbered layers of carbon fiber nonwoven fabric have a weave structure of 0 / 90°.

[0014] Furthermore, the lower and upper layers are each composed of a single layer of carbon fiber nonwoven fabric, and the middle layer is composed of two layers of carbon fiber nonwoven fabric. Each air pore channel in the air pore channel layer between the lower and middle layers is perpendicular to each air pore channel in the air pore channel layer between the middle and upper layers.

[0015] Furthermore, the lower layer, the middle layer, and the upper layer are all composed of a single layer of carbon fiber nonwoven fabric, and each pore channel of the pore channel layer between the lower layer and the middle layer is parallel to each pore channel of the pore channel layer between the middle layer and the upper layer.

[0016] Meanwhile, the present invention also provides a method for preparing the preform of the above-mentioned C / SiC ceramic matrix composite material, comprising the following steps:

[0017] Step 1: Determine if the thickness of the precast body is greater than 20mm. If yes, proceed to step 3; otherwise, proceed to step 2 or step 3.

[0018] Step 2: Set up multiple air vents according to Method 2;

[0019] Step 2.1: Stack multiple layers of carbon fiber nonwoven fabric, and place metal wire layers between the lower and middle layers and between the middle and upper layers of each stacked unit to obtain stacked layers; each metal wire layer includes multiple metal wires that are parallel to each other;

[0020] Step 2.2: The stacked layers obtained in Step 2.1 are sequentially impregnated and cured at high temperature;

[0021] Step 2.3: Extract all the metal wires from the stacked layer obtained in Step 2.2 to obtain multiple air pore channels set according to Method 2, and then execute Step 4;

[0022] Step 3: Set up multiple air vents according to Method 1;

[0023] Step 3.1: Stack multiple layers of carbon fiber nonwoven fabric to obtain a stacked layer;

[0024] Step 3.2: Use a metal needle-like device to physically pressurize and puncture the stacked layers to obtain multiple air pore channels set according to Method 1. Then, impregnate and cure the stacked layers at high temperature in sequence, and then proceed to Step 4.

[0025] Alternatively, multiple metal wires are inserted into the stacked layer along the stacking direction of the multi-layer carbon fiber non-woven fabric, and then the stacked layer is impregnated and cured at high temperature in sequence. Then, the multiple metal wires are pulled out to obtain multiple air pore channels set according to method one, and finally step 4 is executed.

[0026] Step 4: High-temperature carbonization of the stacked layers to obtain a preform of C / SiC ceramic matrix composite material.

[0027] Further, in step 3.2, the specific steps of using a metal needle-like device to physically pressurize and puncture the stacked layers to obtain multiple air channels configured according to method one are as follows:

[0028] Prepare special tooling, which includes a load-bearing plate, a metal connector disposed on the top surface of the load-bearing plate, and a plurality of metal needle-shaped devices disposed on the bottom surface of the load-bearing plate and corresponding to the plurality of air vents disposed in accordance with method one.

[0029] Connect the metal connector to the press, and apply pressure to the load-bearing plate through the press, so that multiple metal needle-like devices pierce the stacked layers to obtain multiple air channels set according to Method 1.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] (1) In the preform of the C / SiC ceramic matrix composite material of the present invention, multiple pore channels are provided in the matrix, which increases the open porosity of the preform, allowing the gaseous precursor to fully diffuse and contact with the fiber bundle inside the preform, thereby improving the rapid conversion of the C / SiC matrix, effectively enhancing the reaction depth of the C / SiC matrix, and thus enabling the preparation of thicker finished products, and effectively shortening the preparation cycle of finished products.

[0032] (2) The present invention provides a method for preparing a preform of a C / SiC ceramic matrix composite material. By performing in-plane puncture on a matrix made of multiple layers of carbon fiber non-woven fabric or by laying metal wires between layers, the porosity of the preform is increased, which solves the problems of long densification cycle and density decay with preform thickness. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of a preform of a C / SiC ceramic matrix composite material according to a first embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the structure of a preform of a C / SiC ceramic matrix composite material according to a second embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the top surface of the matrix in Example 3 of the preform of a C / SiC ceramic matrix composite material according to the present invention;

[0036] Figure 4 This is a schematic diagram of the special tooling in step 3.2.1 of an embodiment of the method for preparing a C / SiC ceramic matrix composite preform of the present invention;

[0037] Figure 5 This is a schematic diagram illustrating the principle of step 3.2.1 in an embodiment of the preparation method of a C / SiC ceramic matrix composite preform of the present invention.

[0038] The reference numerals in the attached drawings are explained as follows: 1-Stacked layer; 2-Carbon fiber nonwoven fabric; 3-Air pore channel; 4-Air pore channel layer; 5-Special tooling; 51-Bearing plate; 52-Metal joint; 53-Metal needle-like device; 6-Stacked unit; 61-Lower layer; 62-Middle layer; 63-Upper layer. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and exemplary embodiments.

[0040] Example 1

[0041] Reference Figure 1 A preform for a C / SiC ceramic matrix composite material, used to prepare C / SiC ceramic matrix composite material using CVI, the preform comprising a matrix formed by stacking N layers of carbon fiber nonwoven fabric 2 and multiple pore channels 3 disposed within the matrix; N is a positive integer greater than or equal to 3.

[0042] The odd-numbered layers of carbon fiber non-woven fabric 2 of the matrix have a weave structure of 0 / 90°, while the even-numbered layers of carbon fiber non-woven fabric 2 have a weave structure of 90 / 0°.

[0043] The N-layer carbon fiber nonwoven fabric 2 includes M stacking units 6. Each stacking unit 6 includes a lower layer 61, a middle layer 62, and an upper layer 63 arranged sequentially from bottom to top. A pore channel layer 4 is provided between the lower layer 61 and the middle layer 62, and between the middle layer 62 and the upper layer 63. The pore channel layer 4 includes a plurality of parallel pore channels 3. The lower layer 61, the middle layer 62, and the upper layer 63 are all composed of a single layer of carbon fiber nonwoven fabric 2. Each pore channel 3 of the pore channel layer 4 between the lower layer 61 and the middle layer 62 is parallel to each pore channel 3 of the pore channel layer 4 between the middle layer 62 and the upper layer 63. M is a positive integer greater than or equal to 1.

[0044] Example 2

[0045] Reference Figure 2 The lower layer 61 and the upper layer 63 are both composed of a single layer of carbon fiber non-woven fabric 2, and the middle layer 62 is composed of two layers of carbon fiber non-woven fabric 2. Each air pore channel 3 of the air pore channel layer 4 between the lower layer 61 and the middle layer 62 is perpendicular to each air pore channel 3 of the air pore channel layer 4 between the middle layer 62 and the upper layer 63.

[0046] All other settings in this embodiment are the same as in Embodiment 1.

[0047] Example 3

[0048] Reference Figure 3A preform of a C / SiC ceramic matrix composite material is used to prepare C / SiC ceramic matrix composite materials using CV1. The preform includes a matrix formed by stacking multiple layers of carbon fiber nonwoven fabric 2 and multiple pore channels 3 disposed in the matrix.

[0049] The odd-numbered layers of carbon fiber non-woven fabric 2 of the matrix have a weave structure of 90 / 0°, while the even-numbered layers of carbon fiber non-woven fabric 2 have a weave structure of 0 / 90°.

[0050] Multiple air pore channels 3 are arranged in a row and column matrix manner. Each air pore channel 3 is set along the stacking direction of the multi-layer carbon fiber non-woven fabric 2 and penetrates each layer of carbon fiber non-woven fabric 2 in sequence.

[0051] A method for preparing a preform of the above-mentioned C / SiC ceramic matrix composite material includes the following steps:

[0052] Step 1: Determine if the thickness of the precast body is greater than 20mm. If yes, proceed to step 2; otherwise, proceed to step 2 or step 3.

[0053] Step 2: Set up multiple air vent channels 3 according to Method 2;

[0054] Step 2.1: Stack multiple layers of carbon fiber nonwoven fabric 2, and set metal wire layers between the lower layer 61 and the middle layer 62, and between the middle layer 62 and the upper layer 63 in each stacking unit 6 to obtain stacked layer 1; each metal wire layer includes multiple metal wires that are parallel to each other.

[0055] Specifically, refer to Figure 1 Each pore channel 3 of each pore channel layer 4 is parallel to each pore channel 3 of the adjacent pore channel layer 4, suitable for preforms with a thickness of 10-20 mm; refer to Figure 2 Each pore channel 3 of each pore channel layer 4 is perpendicular to each pore channel 3 of the adjacent pore channel layer 4, which is suitable for preforms with a thickness of 20 to 50 mm.

[0056] Step 2.2: Impregnate and cure the stacked layer 1 obtained in step 2.1 at high temperature in sequence;

[0057] Step 2.3: Extract all the metal wires from the stacked layer 1 obtained in Step 2.2 to obtain multiple air pore channels 3 set according to Method 2, and then execute Step 4;

[0058] Step 3: Set up multiple air vent channels 3 according to Method 1;

[0059] Step 3.1: Stack multiple layers of carbon fiber nonwoven fabric 2 to obtain stacked layer 1;

[0060] Step 3.2: Execute either step 3.2.1 or step 3.2.2;

[0061] Step 3.2.1, refer to Figure 4 , Figure 5 Prepare a special tooling 5, which includes a load-bearing plate 51, a metal connector 52 on the top surface of the load-bearing plate 51, and a plurality of metal needle-like devices 53 on the bottom surface of the load-bearing plate 51 and corresponding to the plurality of air pore channels 3 set according to method one; connect the metal connector 52 to a press, apply pressure to the load-bearing plate 51 through the press, so that the plurality of metal needle-like devices 53 pierce the stacked layer 1 to obtain the plurality of air pore channels 3 set according to method one, then impregnate and cure the stacked layer 1 in sequence, and then execute step 4;

[0062] The aforementioned metal needle-like device 53 is a steel needle;

[0063] Step 3.2.2, refer to Figure 3 Multiple metal wires are inserted into the stacked layer 1 along the stacking direction of the multi-layer carbon fiber non-woven fabric 2. The stacked layer 1 is then impregnated and cured at high temperature in sequence. Then, the multiple metal wires are pulled out to obtain multiple air pore channels 3 set according to method one. Finally, step 4 is executed.

[0064] Step 4: High-temperature carbonization of stacked layer 1 to obtain a preform of C / SiC ceramic matrix composite material.

Claims

1. A method for preparing a preform of a C / SiC ceramic matrix composite material, comprising the following steps: Step 1: Determine if the thickness of the precast body is greater than 20mm. If yes, proceed to step 3; otherwise, proceed to step 2 or step 3. Step 2: Set up multiple air vent channels (3) according to method 2; Step 2.1: Stack multilayer carbon fiber nonwoven fabric (2). The multilayer carbon fiber nonwoven fabric (2) includes M stacking units (6). Each stacking unit (6) includes a lower layer (61), a middle layer (62), and an upper layer (63) arranged from bottom to top. Metal wire layers are set between the lower layer (61) and the middle layer (62) and between the middle layer (62) and the upper layer (63) of each stacking unit (6) to obtain a stacked layer (1). Each metal wire layer includes multiple parallel metal wires, where M is a positive integer greater than or equal to 1. Step 2.2: Impregnate and cure the stacked layer (1) obtained in step 2.1 at high temperature in sequence; Step 2.3: Extract all the metal wires from the stacked layer (1) obtained in step 2.2 to obtain multiple air pore channels (3) set according to method 2, and then execute step 4; Step 3: Set up multiple air vent channels (3) according to method one; Step 3.1: Stack multiple layers of carbon fiber nonwoven fabric (2) to obtain stacked layer (1); Step 3.2: Insert multiple metal wires into the stacked layer (1) along the stacking direction of the multilayer carbon fiber nonwoven fabric (2), then impregnate the stacked layer (1) in sequence and cure it at high temperature, then pull out the multiple metal wires to obtain multiple air pore channels (3) set according to method one, and finally execute step 4. Step 4: High-temperature carbonization of the stacked layer (1) to obtain a preform of C / SiC ceramic matrix composite material.

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