A silicon carbide fiber reinforced carbon-ceramic composite material and a preparation method thereof

Abstract

The present invention belongs to the technical field of ceramic composite material preparation, and specifically relates to a silicon carbide fiber reinforced carbon ceramic composite material and a preparation method thereof. The preparation method comprises the following steps: (1) laying long-fiber silicon carbide fiber cloth layer by layer, and covering the upper and lower surfaces with two layers of carbon fiber plain cloth, and finally performing a fiber stitching process on the entire body in the longitudinal direction; (2) placing a three-dimensional silicon carbide fiber preform in a precursor gas and densifying it to ≥1.8g / cm by pressure differential chemical vapor infiltration. 3 and peeling off the upper and lower carbon fiber layers; (3) subjecting the C / SIC composite to high-temperature heat treatment under protective gas; (4) placing the C / SIC composite material in silicon powder and subjecting it to high-temperature melt siliconization to produce a carbon-ceramic composite material. The carbon-ceramic material produced by the present invention does not require an impregnation step, and the finished product has high density, high strength, high temperature resistance and other good properties, as well as high tensile strength and low porosity.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic composite material preparation, and in particular relates to a silicon carbide fiber reinforced carbon ceramic composite material and a preparation method thereof. Background Art

[0002] Silicon carbide fiber is a new type of high-performance fiber developed after carbon fiber. It boasts excellent specific strength, impact resistance, and heat resistance in aerobic environments. As a new type of woven skeleton matrix for ceramic composites, silicon carbide fiber exhibits a range of excellent properties, including high-temperature resistance, oxidation resistance, and high tensile strength. It is a national strategic emerging material. Currently, ceramic composites manufactured using silicon carbide fiber have significant application value in the aeroengine field. Western countries have successfully applied such products to improve multiple aeroengine components and enhance their efficiency. As silicon carbide fiber performance continues to improve and production processes are gradually optimized, silicon carbide fiber-reinforced ceramic composites are expected to be used in more aeroengine components in the future and are expected to expand into other high-value civilian applications, with a vast potential market.

[0003] The current preparation of silicon carbide fiber reinforced carbon ceramic composite materials is basically to chopped short silicon carbide fibers and then mixed and pressed. The finished parts have a large number of pores inside and the bulk density is generally less than 2.4g / cm 3 , which indirectly leads to low mechanical properties. In particular, the pressing process includes an impregnation process, which poses a hidden danger to environmental pollution. For example, Chinese patent document CN110862264A discloses a continuous silicon carbide fiber reinforced silicon carbide ceramic matrix composite material and its preparation method and application. The silicon carbide fiber is densified by two steps of CVI pyrolytic carbon + PIP impregnation, but the invention requires multiple chemical vapor infiltration processes and multiple surface treatments, resulting in high technical difficulty, high cost, and slow densification rate; and the invention also uses resin impregnation, the steps are relatively cumbersome, and the fiber may be damaged due to the brittleness of the resin, and there are safety hazards and environmental pollution problems. For another example, CN114890795A discloses a silicon carbide fiber reinforced glass ceramic composite material and its preparation method, which is formed by pressing a silicon carbide fiber cloth coated with prepreg. The invention involves no z-direction fiber connection between silicon carbide fiber layers. Although the preparation cycle is short, the interlayer shear force is insufficient, and the invention has internal pores during the pressing process, resulting in a volume density of less than 2.4g / cm 3 , which ultimately resulted in large differences in mechanical properties and low hidden dangers. Summary of the Invention

[0004] Aiming at the shortcomings of the technology of preparing silicon carbide-silicon carbide fiber composite ceramic parts by chemical vapor deposition cracking, impregnation cracking, etc., such as complex process, low density and mechanical properties, the present invention provides a long silicon carbide fiber reinforced carbon ceramic composite material and its preparation method.

[0005] This method solves many problems in the preparation of long-fiber silicon carbide fiber-reinforced carbon-ceramic composites, such as: the long CVI chemical vapor deposition preparation cycle and multiple shell breakage problems during the process, the high residual porosity of pure silicon ceramics, and the low ceramic density.

[0006] The carbon ceramic material prepared by the present invention does not require an impregnation step, and the finished product has high density, high strength, high temperature resistance and other good properties.

[0007] The technical solution of the present invention is:

[0008] A method for preparing a silicon carbide fiber reinforced ceramic composite material comprises the following steps:

[0009] (1) Laying long-fiber silicon carbide fiber cloth layer by layer, and covering two layers of carbon fiber plain cloth on the upper and lower sides, and finally performing fiber stitching treatment on the entire body longitudinally to form a three-dimensional silicon carbide fiber stitching preform;

[0010] (2) The three-dimensional silicon carbide fiber preform obtained in step (1) is densified in the precursor gas by differential pressure chemical vapor infiltration to a volume density of ≥1.8 g / cm 3 The upper and lower carbon fiber plain fabrics are then peeled off to obtain a C / SIC composite. During this process, the three-dimensional silicon carbide fiber stitched preform of the present invention is suspended within a predetermined cavity using a differential pressure chemical vapor infiltration method for vapor deposition. The three-dimensional silicon carbide fiber stitched preform of the present invention is completely encapsulated in the chemical vapor atmosphere, with no blind spots, achieving full surface carbonization, ultimately resulting in a C / SIC composite.

[0011] (3) subjecting the C / SIC composite obtained in step (2) to a high-temperature heat treatment under a protective gas to obtain a C / SIC composite material; during this process, the deposited carbon in the material structure is transformed from a turbostratic carbon structure to a graphite-like structure, and the internal pore diameter is expanded, which is conducive to increasing the channel for molten silicon and effectively improving the efficiency of high-temperature melt siliconization in step (4);

[0012] (4) The C / SIC composite material obtained in step (3) is placed in silicon powder, with the C / C composite material as support, and is subjected to high-temperature melt siliconization in a protective gas to obtain a bulk density of >2.6 g / cm 3 (up to 2.8g / cm 3 ) of silicon carbide fiber reinforced carbon ceramic composites.

[0013] Preferably, the C / C composite material in step (4) is a carbon fiber and its fabric-reinforced carbon matrix composite material, which can be prepared by conventional methods in the prior art. For example, the preparation method that can be adopted in the present invention is: using a PAN-based carbon fiber 2.5D braided preform, and filling it with carbon through high-temperature cracking of natural gas to densify it to 1.3-1.4 g / cm 3 , then undergo high-temperature heat treatment above 2000℃, and finally be formed into 10×10×20mm blocks through mechanical processing.

[0014] Preferably, in step (1), the long-fiber silicon carbide fiber cloth has a length of 300 to 500 mm and a fineness of 0.8 to 1.2 mm; the carbon fiber cloth covering the upper and lower surfaces has the same length specifications as the silicon carbide fiber cloth and a fineness of 0.6 to 0.7 mm, and the fibers are longitudinally stitched with a fineness of 0.6 to 0.7 mm.

[0015] Further preferably, in step (1), the long-fiber silicon carbide fiber, carbon fiber and suture fiber are all of T700 grade.

[0016] Preferably, the stitching density of the three-dimensional silicon carbide fiber stitching preform prepared in step (1) is (1 to 5) stitches / cm 2 , the volume density is 0.8~0.9g / cm 3 .

[0017] Preferably, the precursor gas in step (2) is a mixture of propane and methane; the flow rate of the precursor gas is 30 to 50 L / min.

[0018] Further preferably, the mass ratio of propane to methane in the precursor gas in step (2) is 1:5.

[0019] Preferably, the pressure differential chemical vapor infiltration method in step (2) is achieved by setting a loading chamber in the furnace cavity of the chemical vapor infiltration furnace; the three-dimensional silicon carbide fiber stitched preform obtained in step (1) is suspended in the loading chamber by a hanging carbon rope; the pressure difference between the inlet and outlet of the loading chamber is 1.0 to 2.0 kPa.

[0020] Preferably, the chemical vapor infiltration time in step (2) is 50 to 70 hours, and the temperature is 1000° C. to 1100° C.

[0021] Preferably, the temperature of the high temperature heat treatment in step (3) is 1500-1600° C., and the time is 1-2 hours.

[0022] Preferably, the particle size of the silicon powder in step (4) is 120 to 250 μm.

[0023] Preferably, the protective gas in step (3) and step (4) is one of high-purity nitrogen, argon or helium.

[0024] Preferably, in step (4), the silicon powder covers more than 2 / 3 of the C / SIC composite material, and the temperature of high-temperature melt siliconization is 1550-1600° C., and the time is 1-3 hours.

[0025] In addition, the present invention also provides a silicon carbide fiber reinforced ceramic composite material prepared by the above preparation method.

[0026] Compared with the prior art, the silicon carbide fiber reinforced carbon ceramic composite material and the preparation method thereof provided by the present invention have the following advantages:

[0027] (1) The present invention provides a special method for preparing a three-dimensional silicon carbide fiber stitched preform, namely, covering the upper and lower surfaces of a long-fiber silicon carbide fiber cloth with carbon fiber plain cloth, stitching them longitudinally, and then directly peeling off the carbon fiber plain cloth layer after CVI chemical vapor deposition is prepared to a certain density, without the need to process and break the silicon carbide fiber layer, thereby shortening the preparation cycle.

[0028] (2) The present invention adopts a suspension treatment in a pressure differential CVI atmosphere. The gas source is pyrolyzed and forced to pass through the porous three-dimensional silicon carbide fiber stitched preform to form pyrolytic carbon. When the three-dimensional silicon carbide fiber stitched preform is suspended in the cavity, its entire surface is completely in 100% contact with the gas source, effectively increasing the contact area of the deposited carbon, and can quickly achieve chemical vapor infiltration. The density can be increased to ≥1.8g / cm within 70 hours. 3 .

[0029] (3) The method provided by the present invention has a short preparation cycle. By using the pressure difference method of chemical vapor infiltration, the gas source is forced to pass through the pores inside the preform, which makes the residual porosity low, the densification rate is accelerated, and the corresponding cost is reduced. At the same time, the tensile strength is significantly improved and can reach 320Mpa.

[0030] (4) The preparation method provided by the present invention does not introduce a resin impregnation step, thereby preventing damage to the fiber caused by the brittleness of resin and other infiltrates; the materials used in the impregnation step are extremely difficult to degrade in the natural environment, and will bring about the destruction of the ecosystem and directly threaten human survival. Therefore, the present invention avoids the pollution to the environment and the harm to human health caused by the resin and other impregnation steps in the production process, and also avoids the safety hazards of impregnation operation and storage.

[0031] (5) The preparation method provided by the present invention adopts the molten silicon infiltration (LSI) method to increase the density, and the silicon powder is covered with the C / SIC composite material. The process is simple to operate and can achieve a volume density greater than 2.6g / cm 3High-density silicon carbide fiber reinforced ceramic composites. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a sandwich-type three-dimensional silicon carbide fiber stitching preform in an embodiment of the present invention;

[0033] Figure 2 Schematic diagram of longitudinal suturing using longitudinal suturing fibers in step (1) of the embodiment;

[0034] Figure 3 Schematic diagram of the differential pressure chemical vapor infiltration process in step (2) of the embodiment;

[0035] Figure 4 Schematic diagram of the charging method for high-temperature melt siliconization in step (4) of the embodiment;

[0036] Figure 5 The silicon carbide fiber reinforced carbon ceramic composite material prepared in Example 1;

[0037] Figure 6 This is the silicon carbide fiber reinforced ceramic composite material prepared in Comparative Example 2.

[0038] The reference numerals involved in the accompanying drawings are:

[0039] 1. Long-fiber silicon carbide fiber cloth; 2. Carbon fiber plain weave cloth; 3. Suspended carbon rope; 4. Three-dimensional silicon carbide fiber stitched preform; 5. C / SIC composite material; 6. Silicon powder; 7. C / C composite material. DETAILED DESCRIPTION

[0040] The present invention is further illustrated below through the description of specific implementation methods, but this is not a limitation of the present invention. Those skilled in the art can make various modifications or improvements based on the basic idea of the present invention, but as long as they do not deviate from the basic idea of the present invention, they are all within the scope of protection of the present invention.

[0041] In the following examples and comparative examples, reagents not otherwise specified are conventional reagents and can be purchased from conventional reagent production and sales companies. The methods used, unless otherwise specified, are all existing technologies.

[0042] The long-fiber silicon carbide fiber cloth and carbon fiber plain weave cloth used in the examples and comparative examples are both available on the market.

[0043] like Figure 1 As shown, the three-dimensional silicon carbide fiber stitched preforms described in Examples 1 to 3 of the present invention are long-fiber silicon carbide fiber cloths sequentially laid flat to the required thickness value 1 (generally 15 layers of 8 mm), and then covered with 2 layers of carbon fiber plain cloth 2 on the upper and lower surfaces, with a certain stitching density as shown in FIG. Figure 2The longitudinal stitching is performed in the direction indicated by the vertical line, and finally a sandwich-type three-dimensional silicon carbide fiber stitching preform is formed.

[0044] Example 1

[0045] A method for preparing a silicon carbide fiber reinforced ceramic composite material comprises the following steps:

[0046] (1) Figure 1 As shown, take a long fiber silicon carbide fiber cloth with a length of 500×500mm and a fineness of 1.0mm and lay it layer by layer; cover the upper and lower surfaces with two layers of 500×500mm carbon fiber plain cloth with a fineness of 0.6mm to form a 500×500×10mm cube, and then sew it together through the longitudinal fibers (as shown in FIG. Figure 2 The fineness of the longitudinal stitched fibers is 0.6 mm, and the final woven volume density is 0.8 g / cm 3 Three-dimensional silicon carbide fiber stitching preform. The stitching density is 5 stitches / cm 2 , the amount of silicon carbide fiber cloth laid is 15 layers, forming a three-dimensional silicon carbide fiber stitched preform;

[0047] (2) Figure 2 As shown, the three-dimensional silicon carbide fiber suture preform obtained in step (1) is placed in a hanging manner in the cavity of a chemical vapor infiltration furnace, and a mixed gas of propane and methane (the mass ratio of propane to methane is 1:5) is used as the precursor gas. The chemical vapor infiltration is carried out at a temperature of 1050°C for 60 hours, the cavity inlet pressure is maintained at 2.0 KPa, the cavity outlet pressure is maintained at 1.0 KPa, and the density is increased to 1.85 g / cm 3 The upper and lower carbon fiber cloths were peeled off to obtain a C / SIC composite; the precursor gas flow rate was 50 L / min;

[0048] (3) placing the C / SIC composite obtained in step (2) in a graphitization furnace, and subjecting it to high-temperature treatment at 1550° C. for 1 h under argon protection to obtain a C / SIC composite material;

[0049] (4) Figure 4 As shown in FIG, the C / SIC composite material obtained in step (3) is placed in silicon powder with a particle size of 200 μm, and the silicon powder covers more than 2 / 3 of the C / SIC composite material. The C / C composite material is used as a support. The material is kept in argon at 1550°C for 2 hours to obtain a bulk density of 2.80 g / cm 3 Silicon carbide fiber reinforced carbon ceramic composites, such as Figure 5 shown.

[0050] The preparation method of the C / C composite material in step (4) is as follows: a PAN-based carbon fiber 2.5D braided preform is used, and the carbon filling is densified to 1.3-1.4 g / cm 3 , then undergo high-temperature heat treatment above 2000℃, and finally be formed into 10×10×20mm blocks through mechanical processing.

[0051] Example 2

[0052] A method for preparing a silicon carbide fiber reinforced ceramic composite material comprises the following steps:

[0053] (1) Take a long-fiber silicon carbide fiber cloth with a length of 500×500mm and a fineness of 0.8mm and lay it layer by layer; cover the upper and lower surfaces with two layers of 500×500mm carbon fiber plain cloth with a fineness of 0.6mm to form a 500×500×10mm cube, and then sew the longitudinal fibers together with a fineness of 0.6mm to finally weave a volume density of 0.9g / cm 3 Three-dimensional silicon carbide fiber stitching preform. The stitching density is 4 stitches / cm 2 , the amount of silicon carbide fiber cloth laid is 15 layers, forming a three-dimensional silicon carbide fiber stitched preform;

[0054] (2) The three-dimensional silicon carbide fiber stitched preform obtained in step (1) was placed in a hanging manner in the cavity of a chemical vapor infiltration furnace, and a mixed gas of propane and methane (the mass ratio of propane to methane was 1:5) was used as the precursor gas. The chemical vapor infiltration was carried out at a temperature of 1000°C for 50 hours, the cavity inlet pressure was maintained at 2.0 KPa, the cavity outlet pressure was maintained at 1.0 KPa, and the density was increased to 1.88 g / cm 3 The upper and lower carbon fiber cloths were peeled off to obtain a C / SIC composite; the precursor gas flow rate was 30 L / min;

[0055] (3) placing the C / SIC composite obtained in step (2) in a graphitization furnace, and subjecting it to high-purity nitrogen protection at a temperature of 1500° C. for 2 h to obtain a C / SIC composite material;

[0056] (4) The C / SIC composite material obtained in step (3) was placed in silicon powder with a particle size of 120 μm, and the silicon powder covered more than 2 / 3 of the C / SIC composite material. The C / C composite material was used as a support. The material was kept in argon at 1550°C for 3 hours to obtain a 2.70 g / cm 3 Carbon ceramic composite material.

[0057] The preparation method of the C / C composite material in step (4) is the same as that in Example 1.

[0058] Example 3

[0059] A method for preparing a silicon carbide fiber reinforced ceramic composite material comprises the following steps:

[0060] (1) Take a long-fiber silicon carbide fiber cloth with a length of 500×500mm and a fineness of 1.2mm and lay it layer by layer; cover the upper and lower surfaces with two layers of 500×500mm carbon fiber plain cloth with a fineness of 0.7mm to form a 500×500×10mm cube, and then sew the longitudinal fibers together with a fineness of 0.7mm to finally weave a volume density of 0.8g / cm 3 Three-dimensional silicon carbide fiber stitching preform. The stitching density is 2 stitches / cm 2 , the amount of silicon carbide fiber cloth laid is 15 layers, forming a three-dimensional silicon carbide fiber stitched preform;

[0061] (2) The three-dimensional silicon carbide fiber stitched preform obtained in step (1) was placed in a hanging manner in the cavity of a chemical vapor infiltration furnace, and a mixed gas of propane and methane (the mass ratio of propane to methane was 1:5) was used as the precursor gas. The chemical vapor infiltration was carried out at a temperature of 1100°C for 70 hours, the cavity inlet pressure was maintained at 2.0 KPa, the cavity outlet pressure was maintained at 1.0 KPa, and the density was increased to 1.85 g / cm 3 The upper and lower carbon fiber cloths were peeled off to obtain a C / SIC composite; the precursor gas flow rate was 40 L / min;

[0062] (3) placing the C / SIC composite obtained in step (2) in a graphitization furnace, and treating it at a temperature of 1600° C. for 1 h under helium protection to obtain a C / SIC composite material;

[0063] (4) The C / SIC composite material obtained in step (3) was placed in silicon powder with a particle size of 250 μm, wherein the silicon powder covered more than 2 / 3 of the C / SIC composite material, and the C / C composite material was used as a support. The material was kept in argon at 1600°C for 1 hour to obtain a bulk density of 2.75 g / cm 3 carbon ceramic composite materials.

[0064] The preparation method of the C / C composite material in step (4) is the same as that in Example 1.

[0065] Comparative Example 1

[0066] Compared with Example 1, the difference of Comparative Example 1 is that the method for preparing pyrolytic carbon of the three-dimensional silicon carbide fiber preform by the pressure differential chemical vapor infiltration method (CVI) in step (2) is different from that in Example 1, and the specific steps are as follows:

[0067] The three-dimensional silicon carbide fiber preform obtained in step (1) was directly placed flat in a CVI gas source atmosphere (the mass ratio of propane and methane was 1:5) for pyrolysis carbon acquisition. The temperature was 1000 ° C, and the chemical vapor infiltration was carried out for 50 hours. The pressure values of the cavity inlet and outlet were kept consistent, both at 2 KPa, and the density was increased to 1.8 g / cm 3 , a C / SIC composite is obtained; the precursor gas flow rate is adjusted according to the pressure difference. Other parameters and operations are the same as those in Example 1.

[0068] Comparative Example 2

[0069] A method for preparing a silicon carbide fiber reinforced ceramic composite material, wherein a single layer of silicon carbide fiber cloth prepreg is pressed and formed, and the specific steps are as follows:

[0070] Step (1) borosilicate glass powder, silicon carbide, phenolic resin powder and water are mixed uniformly in a weight ratio of 5:7:3:11 to obtain a glass ceramic solution, and then 1% of the mass of the glass ceramic solution is added into the glass ceramic solution as a polyvinylpyrrolidone dispersant to fully dissolve the mixture to form a coating;

[0071] Step (2): applying the coating obtained in step (1) on the surface of a single layer of silicon carbide fiber cloth;

[0072] Step (3): stack 8 to 10 layers of the single-layer silicon carbide fiber cloth with coating obtained in step (2) and then press it, heat it to 900℃, apply pressure of 9 to 10 MPa, keep it warm for 2 hours, and the density of the semi-finished product after being taken out of the oven is 2.2 to 2.4 g / cm 3 ;

[0073] Step (4): Place the semi-finished product obtained in step (3) into a high-temperature furnace for ablation treatment, heat it to 1500°C, and keep it warm for 2 hours to obtain a bulk density of 2.25g / cm 3 Silicon carbide fiber reinforced ceramic composites.

[0074] Test Example 1: Performance Test of Silicon Carbide Fiber Reinforced Carbon Ceramic Composite Material Prepared by the Present Invention

[0075] The performance test of the silicon carbide fiber reinforced carbon ceramic composite materials prepared in Examples 1 to 3 and Comparative Examples 1 to 2 of the present invention was carried out, wherein the density (g / cm 3 ) was measured using the weighing method. Tensile strength (MPa) was measured according to GJB 8736-2015, Test Method for Room-Temperature Tensile Properties of Continuous Fiber-Reinforced Ceramic Matrix Composites; apparent porosity (%) was measured according to GB / T 1966-1996, Test Method for Apparent Porosity and Bulk Density of Porous Ceramics. The results are shown in Table 1:

[0076] Table 1 Performance test data of silicon carbide fiber reinforced carbon ceramic composites As shown in Table 1, after testing the density, tensile strength, apparent porosity and temperature resistance of the silicon carbide fiber reinforced carbon ceramic composite materials prepared in Examples 1 to 3 of the present invention and Comparative Examples 1 to 2, it can be seen that the density of the silicon carbide fiber reinforced carbon ceramic composite materials prepared by the preparation method of the present invention is greater than 2.6 g / cm 3 , high tensile strength, low apparent porosity, and can remain intact at 1000℃ for 0.5h in an aerobic environment. However, the various indicators of the carbon-ceramic composite material prepared in the comparative example have declined to varying degrees.

[0077] This fully illustrates:

[0078] 1. The present invention utilizes a special weaving method of a preform with a surface covered with carbon fiber cloth and a sandwich of silicon carbide fiber cloth to sew the preform. The process omits the surface machining and shell breaking process after the CVI process. Only the carbon fiber cloth needs to be peeled off, which saves time and effort.

[0079] 2. The volume density of silicon carbide fiber reinforced ceramic composites is related to the CVI deposition density. As the CVI volume density increases, the density of the final ceramic composites becomes higher. 3 When , the final apparent porosity appears low.

[0080] 3. Compared with the traditional chemical vapor infiltration method, the present invention utilizes the pressure differential suspension chemical vapor infiltration method, which has the advantages of fast CVI deposition rate, high gas source utilization, minimum apparent porosity change, and uniform carbon deposition.

[0081] 4. The present invention utilizes long-fiber silicon carbide fiber stitched preforms to prepare ceramic composite materials through pure CVI deposited carbon and pure molten silicon methods, which have the highest volume density and the best oxidation resistance and temperature resistance.

[0082] In summary, from the three indicators of volume density, tensile strength, and apparent porosity prepared by CVI in Table 1, it can be concluded that the ceramic composite material prepared by the special three-dimensional silicon carbide fiber stitched preform weaving method of the present invention and the pressure differential suspension chemical vapor infiltration method has the best comprehensive indicators and the shortest and lowest cycle.

[0083] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for preparing a silicon carbide fiber reinforced ceramic composite material, characterized in that: The steps include: (1) Laying long-fiber silicon carbide fiber cloth layer by layer, and covering two layers of carbon fiber plain cloth on the upper and lower sides, and finally performing fiber stitching treatment on the entire body longitudinally to form a three-dimensional silicon carbide fiber stitching preform; (2) The three-dimensional silicon carbide fiber preform obtained in step (1) is densified in the precursor gas by differential pressure chemical vapor infiltration to a volume density of ≥1.8 g / cm 3 and peeling off the upper and lower carbon fiber plain fabrics to obtain a C / SiC composite; (3) subjecting the C / SiC composite obtained in step (2) to high-temperature heat treatment under a protective gas to obtain a C / SiC composite material; (4) The C / SiC composite material obtained in step (3) is placed in silicon powder, with the C / C composite material as a support, and is subjected to high-temperature melt siliconization in a protective gas to obtain a bulk density of >2.6 g / cm 3 Silicon carbide fiber reinforced carbon ceramic composites.

2. The method for preparing the silicon carbide fiber reinforced ceramic composite material according to claim 1, characterized in that: In the step (1), the long-fiber silicon carbide fiber cloth has a length of 300 to 500 mm and a fineness of 0.8 to 1.2 mm; the carbon fiber cloth covering the upper and lower surfaces has the same length specification as the silicon carbide fiber cloth and a fineness of 0.6 to 0.7 mm; and the fineness of the longitudinal stitching fiber is 0.6 to 0.7 mm.

3. The method for preparing the silicon carbide fiber reinforced ceramic composite material according to claim 1, characterized in that: In the step (1), the long-fiber silicon carbide fiber, carbon fiber and suture fiber are all of T700 grade.

4. The method for preparing the silicon carbide fiber reinforced ceramic composite material according to claim 1, wherein: The stitching density of the three-dimensional silicon carbide fiber stitching preform prepared in step (1) is (1 to 5) needles / cm 2 , the volume density is 0.8~0.9g / cm 3 .

5. The method for preparing the silicon carbide fiber reinforced ceramic composite material according to claim 1, characterized in that: The precursor gas in step (2) is a mixture of propane and methane; the flow rate of the precursor gas is 30 to 50 L / min.

6. The method for preparing the silicon carbide fiber reinforced ceramic composite material according to claim 1, characterized in that: The pressure differential chemical vapor infiltration method in step (2) is achieved by setting a loading chamber in the furnace cavity of the chemical vapor infiltration furnace; the three-dimensional silicon carbide fiber stitched preform obtained in step (1) is suspended in the loading chamber by a hanging carbon rope; the pressure difference between the inlet and outlet of the loading chamber is 1.0 to 2.0 kPa; the time of the chemical vapor infiltration is 50 to 70 hours, and the temperature is 1000° C. to 1100° C.

7. The method for preparing the silicon carbide fiber reinforced ceramic composite material according to claim 1, characterized in that: The temperature of the high temperature heat treatment in step (3) is 1500-1600° C. and the time is 1-2 hours.

8. The method for preparing the silicon carbide fiber reinforced ceramic composite material according to claim 1, characterized in that: The protective gas in step (3) and step (4) is one of high-purity nitrogen, argon or helium.

9. The method for preparing the silicon carbide fiber reinforced ceramic composite material according to claim 1, characterized in that: The particle size of the silicon powder in step (4) is 120-250 μm; the silicon powder covers more than 2 / 3 of the C / SiC composite material, the temperature of high-temperature melt siliconization is 1550-1600° C., and the time is 1-3 hours.

10. A silicon carbide fiber reinforced ceramic composite material prepared according to the preparation method according to any one of claims 1 to 9.

Images