SiC ceramic matrix composite material and preparation method and application thereof

Abstract

The application discloses a SiC ceramic matrix composite material and a preparation method and application thereof, and belongs to the technical field of ceramic matrix composite materials.The organic resin is dissolved in a dissolving solution to obtain an organic dissolving solution; the organic dissolving solution and inorganic powder are mixed and uniformly stirred and dispersed to obtain liquid premix; a precipitation agent is added to the liquid premix to precipitate and obtain wet powder coated with resin; the wet powder is sequentially subjected to water washing and drying to obtain powder coated with resin; and the powder coated with resin is sequentially subjected to hot-pressing forming, carbonization and metal infiltration to obtain the SiC ceramic matrix composite material.The SiC ceramic matrix composite material preparation method does not need to spray granulation or high-speed mechanical crushing on the powder coated with organic SiC ceramic matrix composite material in the preparation process, compared with traditional short-cut fiber powder, the length of reinforcing fibers such as carbon fibers and silicon carbide is ensured, and the strength and toughness of the SiC ceramic matrix composite material are improved.

Description

Technical Field

[0001] This invention belongs to the field of ceramic matrix composite technology, specifically relating to a SiC ceramic matrix composite material, its preparation method, and its application. Background Technology

[0002] SiC ceramic matrix composites have wide applications in chemical, aerospace, and other fields due to their low density, high modulus, low thermal expansion, and high corrosion resistance. SiC ceramics prepared via reactive infiltration offer advantages such as low shrinkage, short preparation cycle, and near-net-shape molding. Adding SiC fibers or carbon fibers to SiC ceramics can further improve their toughness.

[0003] CN102219518A discloses a method for preparing boron carbide / silicon carbide multiphase ceramics. The specific preparation process involves ball milling and mixing B4C (boron carbide) powder and C powder in an organic solvent until homogeneous, followed by drying and pulverizing to obtain an organically coated powder material. Finally, this powder is preformed, degreased, and subjected to reactive melting and sintering to obtain the B4C / SiC multiphase ceramic.

[0004] CN106083061B discloses a method for preparing silicon carbide ceramics using laser sintering rapid prototyping. The specific preparation process involves adding SiC powder, phenolic resin, carbon black, and acetone to a grinder and mixing them evenly. Then, spray granulation and drying are used to obtain powder for preparing SiC ceramic matrix composites for laser sintering. Finally, this powder is laser-sintered and reacted to obtain SiC ceramics.

[0005] The paper "Fabrication and characterization of carbon fiber reinforced SiCceramic matrix composites based on 3D printing technology" discloses a method for preparing SiC ceramics based on carbon fibers and phenolic resin. The specific preparation process involves dispersing short-cut carbon fibers in an acetone solution of phenolic resin, followed by drying and pulverization to obtain phenolic resin-coated short-cut carbon fiber powder (fiber length 50-220 μm). Finally, this powder is subjected to laser selective localization molding, high-temperature carbonization, secondary PIP carbonization, and high-temperature reactive infiltration to obtain SiC ceramics.

[0006] When preparing SiC ceramic matrix composites using the above methods, the powder used for SiC ceramic matrix composites needs to undergo a high-speed granulation stage, requiring specialized crushing or granulation equipment. Due to the high hardness of SiC, the equipment is easily damaged during crushing and granulation. At the same time, during the crushing or granulation process, the carbon fibers in the material are prone to breakage during high-speed crushing, resulting in a relatively short fiber length in the final SiC ceramic, that is, the fiber length in the material is at the micrometer level, which cannot meet the requirements of millimeter-level materials. Summary of the Invention

[0007] To address the problem that secondary crushing or granulation of SiC ceramics during the preparation process in existing technologies shortens the fiber length in SiC ceramics, making it difficult to prepare SiC ceramic matrix composites containing short-cut fibers with millimeter-scale lengths, this invention provides a SiC ceramic matrix composite material, its preparation method, and its application.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for preparing SiC ceramic matrix composite materials specifically includes the following steps:

[0010] S1, Dissolve the organic resin in the solvent to obtain an organic solvent with a mass concentration of 10-50%;

[0011] S2, mix the organic solvent and inorganic powder, stir and disperse evenly to obtain a liquid premix;

[0012] S3, add a precipitant to the liquid premix to precipitate and obtain resin-coated wet powder;

[0013] S4, the wet powder is washed with water and dried in sequence to obtain resin-coated powder;

[0014] S5, the resin-coated powder is sequentially subjected to hot pressing, carbonization, and metal infiltration to obtain SiC ceramic matrix composite material.

[0015] Preferably, the solution in S1 is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, sulfolane, and N-methylpyrrolidone.

[0016] Preferably, the mass ratio of the organic solvent to the inorganic powder in S2 is 1:(0.1 to 0.4).

[0017] Preferably, the inorganic powder is one or more of the following: SiC powder, SiN powder, B4C powder with a particle size between 1 and 50 μm, or short-cut carbon fibers or SiC fibers with a length between 0.1 and 10 mm.

[0018] Preferably, the precipitant in S3 is obtained according to the following process:

[0019] The precipitant is obtained by mixing the solution with deionized water at a mass ratio of 1:(0.3-0.8).

[0020] The addition rate of the precipitant is 0.5wt%-2wt% / min.

[0021] Preferably, the washing and drying processes described in S4 are as follows:

[0022] Deionized water and wet powder were loaded into a reaction vessel at a weight ratio of 2 to 3:1. The temperature in the reaction vessel was adjusted to 60 to 100°C. After stirring and soaking for 2 to 3 hours, the powder was separated using a centrifuge to obtain the water-washed powder.

[0023] The washed powder was placed on a fluidized bed at a temperature of 60–100°C until constant weight was achieved, resulting in resin-coated powder.

[0024] Preferably, the hot pressing molding described in S5 is selected from either compression molding or autoclave molding; the carbonization temperature is 800-1500℃.

[0025] Preferably, the metal selected for metal infiltration in S5 is one or more of elemental Si, Si-Zr alloy, Hf-Si-B alloy, or Hf-Zr-Si-Ta alloy; the metal infiltration temperature is 1500-2000℃.

[0026] A SiC ceramic matrix composite material is prepared by the above-described method for preparing a SiC ceramic matrix composite material.

[0027] Preferably, a SiC ceramic matrix composite material is used in the preparation of space mirror supports and chemical heat exchangers.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] The method for preparing SiC ceramic matrix composites provided by this invention involves uniformly dispersing inorganic powder in an organic solvent prepared from organic resin and a solvent, and then gradually adding a precipitating agent under stirring conditions. The organic resin will crystallize and precipitate with the inorganic powder as the core, resulting in a wet powder coated with organic resin. Finally, the ceramic matrix composite is prepared by water washing, drying, hot pressing, and metal infiltration. This method for preparing SiC ceramic matrix composites does not require spray granulation or high-speed mechanical crushing of the prepared material. Compared with traditional short-cut fiber powder, this preparation method yields resin-coated powder with longer fiber lengths, ensuring the length of reinforcing fibers such as carbon fiber and silicon carbide, thereby preparing ceramic matrix composites reinforced with millimeter-length fibers.

[0030] Furthermore, in the SiC ceramic matrix composite material preparation method provided by the present invention, the solution is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, sulfolane, and N-methylpyrrolidone, which can induce crystallization of organic resin.

[0031] Furthermore, in the SiC ceramic matrix composite material preparation method provided by the present invention, the mass ratio of organic solvent to inorganic powder is 1:(0.1~0.4). This ratio allows the organic resin to fully coat the inorganic powder, avoiding excessive inorganic powder, which would affect the performance of the prepared ceramic matrix composite material. Excessive filler content would affect the fluidity of inorganic powder in the organic solvent, thereby reducing the overall preparation rate, affecting the industrial production efficiency of SiC ceramic matrix composite materials, and increasing production costs.

[0032] Furthermore, in the SiC ceramic matrix composite material preparation method provided by this invention, the precipitant is obtained by mixing the solution and deionized water at a mass ratio of 1:(0.3~0.8). This ratio ensures that the addition of the precipitant to the liquid premix allows for stable precipitation, avoiding excessive use of deionized water, which could lead to excessive local precipitation of the organic resin-coated SiC ceramic matrix composite powder during precipitation, thus reducing the performance of the organic resin-coated SiC ceramic matrix composite powder. Insufficient use of deionized water will prevent the precipitation process from proceeding smoothly. Simultaneously, the precipitant is added at a rate of 0.5wt%-2wt% / min to avoid local agglomeration of the organic resin-coated SiC ceramic matrix composite powder caused by an excessively rapid addition rate, while an excessively slow rate would affect the preparation efficiency of the organic resin-coated SiC ceramic matrix composite powder.

[0033] The present invention also discloses a powder raw material for preparing the SiC ceramic matrix composite material, wherein the powder contains short chopped fibers with a length of millimeters, which significantly improves the strength and toughness of the SiC ceramic matrix composite material and increases the application range of the SiC ceramic matrix composite material.

[0034] This invention also discloses the application of SiC ceramic matrix composites. Because the fiber length in the powder used to coat SiC ceramic matrix composites with organic resin reaches the millimeter level, the strength and toughness of SiC ceramic matrix composites are significantly improved. This gives the material significant application advantages in high-temperature fields, heating and heat exchange industries, corrosive environments, wear-resistant machinery, national defense and military industries, optics, semiconductors, and nuclear industries. In particular, space mirror brackets and chemical heat exchangers produced using this material have higher hardness and significantly improved durability. Attached Figure Description

[0035] Figure 1 The flowchart illustrates the method for preparing SiC ceramic matrix composite materials provided by this invention.

[0036] Figure 2 Microscopic image of the powder for organic resin-coated SiC ceramic matrix composite material provided by the present invention;

[0037] Figure 3 Microscopic images of powders used in SiC ceramic matrix composites prepared by traditional pulverization;

[0038] Figure 4 The bending stress-strain curve of the SiC ceramic matrix composite material provided by the present invention. Detailed Implementation

[0039] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0040] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0042] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0045] See Figure 1 This invention discloses a method for preparing SiC ceramic matrix composite materials, specifically including the following steps:

[0046] S1, Dissolve the organic resin in the solvent to obtain an organic solvent with a mass concentration of 10-50%;

[0047] Specifically, the steps include the following:

[0048] Preparation of organic resin: Prepare diphenols, paraformaldehyde and aniline containing rigid benzene ring structures, and weigh the required amounts of diphenols, paraformaldehyde and aniline containing rigid benzene ring structures;

[0049] Toluene was added to the reaction vessel, and then weighed aniline was added under stirring. After the aniline was added, paraformaldehyde was added in batches. After all the paraformaldehyde was added, the mixture was reacted at room temperature for 2 hours. Then, a diphenol with a rigid benzene ring structure was added to the mixture, and the temperature was raised to 90°C and reacted for 8 hours. After the reaction was completed, the water in the system was separated and then washed three times with NaOH aqueous solution. Finally, the material was washed with pure water until the pH was neutral. After separation and drying, the solvent was removed by rotary evaporation to obtain the organic resin.

[0050] Among them, the diphenol containing a rigid benzene ring structure is selected from one or more of hydroquinone, catechol, resorcinol or biphenyl;

[0051] Add the solvent and organic resin to the reaction vessel, and raise the temperature of the reaction vessel to 100-120°C to completely dissolve the organic resin in the solvent, thereby obtaining an organic solvent with a mass concentration of 10-50%.

[0052] The solvent is selected from one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), N-methylpyrrolidone (NMP), and sulfolane (TMS);

[0053] S2, mix the organic solvent and inorganic powder, stir and disperse evenly to obtain a liquid premix.

[0054] Specifically, inorganic powder is added to the container S1 containing an organic solvent with a mass concentration of 10-50%, and the mass ratio of the organic solvent to the inorganic powder is 1:(0.1-0.4).

[0055] The selected inorganic powder is added to the reaction vessel at a constant rate, and mechanical stirring is performed during the process of adding the inorganic powder at a constant rate, so that the inorganic powder is evenly dispersed in the organic solution to obtain a liquid premix.

[0056] Among them, the inorganic powder is one or more of SiC powder, SiN powder, B4C powder with a particle size between 1 and 50 μm, or short-cut carbon fiber or SiC fiber with a length between 0.1 and 10 mm.

[0057] S3, add a precipitant to the liquid premix to precipitate and obtain resin-coated wet powder.

[0058] Specifically, the dissolving solution and deionized water are measured, with a mass ratio of 1:(0.3 to 0.8). The deionized water is mixed with the dissolving solution to prepare a precipitant. The precipitant is then added to the reactor containing the liquid premix at a rate of 0.5 wt% to 2 wt% / min, and the mixture is stirred at a constant speed during the addition of the precipitant to obtain a resin-coated wet powder.

[0059] S4, the wet powder is washed with water and dried in sequence to obtain resin-coated powder;

[0060] Add deionized water to the reactor containing the resin-coated wet powder, with a weight ratio of deionized water to resin-coated wet powder of 2-3:1. Raise the reactor temperature to 60-100℃, stir and soak for 2-3 hours. Transfer the material from the reactor to a centrifuge, separating the liquid and powder to obtain washed powder. Repeat this process 2-5 times. Check if the content of the dissolved liquid in the washed powder is less than 2%. If the result shows that the content of the dissolved liquid is less than 2%, stop washing. If the result shows that the content of the dissolved liquid is greater than 2%, continue washing until the result shows that the content of the dissolved liquid is greater than 2%.

[0061] The water-washed powder with a solution content of less than 2% as shown by the test results was transferred to a fluidized bed. The temperature of the fluidized bed was set to 60-100℃, and the water-washed powder was dried until the water-washed powder reached a constant weight, thus obtaining resin-coated powder.

[0062] S5, the resin-coated powder is sequentially subjected to hot pressing, carbonization, and metal infiltration to obtain SiC ceramic matrix composite material.

[0063] Specifically, the resin-coated powder is transferred to a hot press molding equipment, the hot press molding pressure is set to 0.1-3.0MPa, the temperature is 100-220℃, and the resin-coated powder is cured and molded to obtain a cured resin blank.

[0064] The cured resin blank is loaded into a carbonization furnace, and the temperature of the carbonization furnace is raised to 800-1500℃ to carbonize the resin blank and obtain a carbon-carbon blank.

[0065] The carbon-carbon preform is transferred to a metal infiltration furnace, metal is added to the furnace, and the temperature of the furnace is set to 1500-2000℃ to begin metal infiltration of the carbon-carbon preform, thus obtaining a ceramic matrix composite material.

[0066] Among them, hot pressing forming uses either a vacuum press or a hot autoclave; the metal used for metal infiltration is one or more of elemental Si, Si-Zr alloy, Hf-Si-B alloy, or Hf-Zr-Si-Ta alloy; among them, Si-Zr alloy is a binary alloy containing Si and Zr elements such as SiZr10, Hf-Si-B alloy is a ternary alloy containing Hf, Si, B, etc. such as Hf10Si2B, and Hf-Zr-Si-Ta alloy is a quaternary alloy containing Hf, Zr, Si, Ta, etc. such as 40Hf31Zr10Si15Ta4.

[0067] In this invention, an organic solution is prepared by dissolving organic resin in a solvent. Inorganic powder is then added to the organic solution and stirred to ensure uniform dispersion of the inorganic powder, resulting in a liquid premix. The liquid premix is ​​then precipitated by a precipitant to obtain a wet powder coated with organic resin. This powder is then processed through steps such as washing, drying, hot pressing, and metal infiltration to prepare a SiC ceramic matrix composite material. This preparation process eliminates the need for secondary crushing or spray granulation of the material, thus ensuring the length of the carbon fibers in the SiC ceramic matrix composite material and producing a SiC ceramic matrix composite material that meets the length requirements of millimeter-scale materials.

[0068] The following examples further explain and illustrate the preparation method of a SiC ceramic matrix composite material provided by the present invention;

[0069] Example 1:

[0070] Toluene was added to the reaction vessel, and then aniline was added under stirring. After the aniline was added, paraformaldehyde was added in batches. After all the paraformaldehyde was added, the mixture was reacted at room temperature for 2 hours. Then, biphenyl hydroquinone was added to the mixture, and the temperature was raised to 90°C and reacted for 8 hours. After the reaction was completed, the water in the system was separated and then washed three times with NaOH aqueous solution. Finally, the material was washed with pure water until the pH was neutral. After separation and drying, the solvent was removed by rotary evaporation to obtain the organic resin.

[0071] The temperature of the reactor is raised to 120°C, and N,N-dimethylformamide is added to the reactor containing the organic resin, so that the organic resin is completely dissolved in N,N-dimethylformamide to obtain an organic solution with a mass concentration of 50%.

[0072] Then, SiC powder with a particle size of 50 μm was selected, and the mass ratio of the organic solvent to the SiC powder with a particle size of 50 μm was 1:0.4.

[0073] SiC powder with a particle size of 50μm was added at a constant speed to a reaction vessel containing an organic solvent, and mechanical stirring was performed to ensure that the SiC powder with a particle size of 50μm was uniformly dispersed in the organic solvent, thus obtaining a liquid premix.

[0074] Measure N,N-dimethylformamide and deionized water, with a mass ratio of N,N-dimethylformamide to deionized water of 1:0.3. Mix the deionized water with N,N-dimethylformamide to prepare a precipitant. Then, add the precipitant to the reactor containing the liquid premix at a rate of 0.5 wt% / min, and stir at a constant speed during the addition of the precipitant to obtain resin-coated wet powder.

[0075] Deionized water was added to the reactor containing the resin-coated wet powder, with a weight ratio of deionized water to resin-coated wet powder of 2:1. After raising the temperature of the reactor to 80°C and stirring and soaking for 2 hours, the material in the reactor was transferred to a centrifuge. The liquid and powder in the material were separated by centrifugation to obtain water-washed powder. The above operation was repeated 3 times. The content of the dissolved liquid in the water-washed powder was then checked to see if it was less than 2%. If the test result showed that the content of the dissolved liquid was less than 2%, the water washing was stopped; if the test result showed that the content of the dissolved liquid was greater than 2%, the water washing operation was continued until the test result showed that the content of the dissolved liquid was less than 2%.

[0076] The water-washed powder, whose content of dissolved liquid was less than 2% as shown by the test results, was transferred to a fluidized bed. The temperature of the fluidized bed was set to 80℃, and the water-washed powder was dried until the water-washed powder reached a constant weight, thus obtaining resin-coated powder (BPBZ / 50SiC).

[0077] The resin-coated powder (BPBZ / 50SiC) is transferred into a vacuum press, and the hot pressing pressure is set to 2.0MPa and the temperature to 200℃. The resin-coated powder (BPBZ / 50SiC) is then cured and molded to obtain a cured resin blank.

[0078] The resin blank is placed in a carbonization furnace, and the temperature of the carbonization furnace is raised to 1000℃ for carbonization treatment to obtain a carbon-carbon blank.

[0079] The carbon-carbon preform was transferred to a metal infiltration furnace, and elemental Si was added to the furnace. The temperature of the furnace was set to 1700℃, and vacuum metal infiltration of the carbon-carbon preform was started to obtain a ceramic matrix composite material (BPBZ / 50SiC / Si-CMC).

[0080] Example 2:

[0081] Toluene was added to the reaction vessel, and then aniline was added under stirring. After the aniline was added, paraformaldehyde was added in batches. After all the paraformaldehyde was added, the mixture was reacted at room temperature for 2 hours. Then, biphenyl hydroquinone was added to the mixture, and the temperature was raised to 90°C and reacted for 8 hours. After the reaction was completed, the water in the system was separated and then washed three times with NaOH aqueous solution. Finally, the material was washed with pure water until the pH was neutral. After separation and drying, the solvent was removed by rotary evaporation to obtain the organic resin.

[0082] The temperature of the reactor is raised to 120°C, and N,N-dimethylformamide is added to the reactor containing the organic resin, so that the organic resin is completely dissolved in N,N-dimethylformamide to obtain an organic solution with a mass concentration of 30%.

[0083] Then, 3mm short-cut pitch-based carbon fiber TC-HC-600 (HC600-S3mm) powder was selected, and the mass ratio of the organic solvent to the 3mm short-cut pitch-based carbon fiber TC-HC-600 (HC600-S3mm) powder was 1:0.3.

[0084] Short-cut pitch-based carbon fiber TC-HC-600 (HC600-S3mm) powder with a particle size of 3mm was added at a constant speed to a reaction vessel containing an organic solvent and mechanically stirred to uniformly disperse the 3mm pitch-based carbon fiber TC-HC-600 (HC600-S3mm) powder in the organic solvent, thus obtaining a liquid premix.

[0085] Measure N,N-dimethylformamide and deionized water, with a mass ratio of N,N-dimethylformamide to deionized water of 1:0.5. Mix the deionized water with N,N-dimethylformamide to prepare a precipitant. Then, add the precipitant to the reactor containing the liquid premix at a rate of 2 wt% / min, and stir at a constant speed during the addition of the precipitant to obtain resin-coated wet powder.

[0086] Deionized water was added to the reactor containing the resin-coated wet powder, with a weight ratio of deionized water to resin-coated wet powder of 3:1. After raising the temperature of the reactor to 80°C and stirring and soaking for 3 hours, the material in the reactor was transferred to a centrifuge. The liquid and powder in the material were separated by centrifugation to obtain water-washed powder. The above operation was repeated 3 times. The content of the dissolved liquid in the water-washed powder was then checked to see if it was less than 2%. If the test result showed that the content of the dissolved liquid was less than 2%, the water washing was stopped; if the test result showed that the content of the dissolved liquid was greater than 2%, the water washing operation was continued until the test result showed that the content of the dissolved liquid was less than 2%.

[0087] The water-washed powder, whose content of dissolved liquid was less than 2% as shown by the test results, was transferred to a fluidized bed. The temperature of the fluidized bed was set to 80℃, and the water-washed powder was dried until the water-washed powder reached a constant weight, thus obtaining resin-coated powder (BPBZ / HC600-S3mm).

[0088] The resin-coated powder (BPBZ / HC600-S3mm) is transferred into an autoclave, and the pressure for hot pressing is set to 0.9MPa and the temperature to 190℃. The resin-coated powder (BPBZ / HC600-S3mm) is then cured and molded to obtain a resin preform.

[0089] The resin blank is placed in a carbonization furnace, and the temperature of the carbonization furnace is raised to 1200℃ for carbonization treatment to obtain a carbon-carbon blank.

[0090] The carbon-carbon preform was transferred to a metal infiltration furnace, and elemental Si was added to the furnace. The temperature of the furnace was set to 1500℃, and vacuum metal infiltration of the carbon-carbon preform was started to obtain a ceramic matrix composite material (BPBZ / HC600-S3mm / Si-CMC).

[0091] Example 3:

[0092] Toluene was added to the reactor, and then aniline was added under stirring. After the aniline was added, paraformaldehyde was added in batches. After all the paraformaldehyde was added, the mixture was reacted at room temperature for 2 hours. Then hydroquinone was added to the mixture, and the temperature was raised to 90°C and reacted for 8 hours. After the reaction was completed, the water in the system was separated and then washed three times with NaOH aqueous solution. Finally, the material was washed with pure water until the pH was neutral. After separation and drying, the solvent was removed by rotary evaporation to obtain the organic resin.

[0093] The temperature of the reactor is raised to 120°C, and N,N-dimethylacetamide is added to the reactor containing the organic resin, so that the organic resin is completely dissolved in N,N-dimethylacetamide to obtain an organic solution with a mass concentration of 30%.

[0094] Then, SiC powder with a particle size of 30 μm was selected, and the mass ratio of the organic solvent to the SiC powder with a particle size of 30 μm was 1:0.2.

[0095] SiC powder with a particle size of 30μm was added at a constant speed to a reaction vessel containing an organic solvent and mechanically stirred to uniformly disperse the SiC powder with a particle size of 30μm in the organic solvent, thus obtaining a liquid premix.

[0096] Measure N,N-dimethylacetamide and deionized water, with a mass ratio of N,N-dimethylacetamide to deionized water of 1:0.8. Mix the deionized water with N,N-dimethylacetamide to prepare a precipitant. Then, add the precipitant to the reactor containing the liquid premix at a rate of 1.5 wt% / min, and stir at a constant speed during the addition of the precipitant to obtain resin-coated wet powder.

[0097] Deionized water was added to the reactor containing the resin-coated wet powder, with a weight ratio of deionized water to resin-coated wet powder of 3:1. After raising the temperature of the reactor to 90°C and stirring and soaking for 3 hours, the material in the reactor was transferred to a centrifuge. The liquid and powder in the material were separated by centrifugation to obtain water-washed powder. The above operation was repeated 3 times. The content of the dissolved liquid in the water-washed powder was then checked to see if it was less than 2%. If the test result showed that the content of the dissolved liquid was less than 2%, the water washing was stopped; if the test result showed that the content of the dissolved liquid was greater than 2%, the water washing operation was continued until the test result showed that the content of the dissolved liquid was less than 2%.

[0098] The water-washed powder, whose content of dissolved liquid was less than 2% as shown by the test results, was transferred to a fluidized bed. The temperature of the fluidized bed was set to 90℃, and the water-washed powder was dried until the water-washed powder reached a constant weight, thus obtaining resin-coated powder (HQBZ / 30SiC / T300-S1mm).

[0099] The resin-coated powder (HQBZ / 30SiC / T300-S1mm) is transferred into a vacuum press, and the hot pressing pressure is set to 2.5MPa and the temperature is 190℃. The resin-coated powder (HQBZ / 30SiC / T300-S1mm) is cured and molded to obtain a cured resin blank.

[0100] The resin blank is placed in a carbonization furnace, and the temperature of the carbonization furnace is raised to 800℃ for carbonization treatment to obtain a carbon-carbon blank.

[0101] The carbon-carbon preform was transferred to a metal infiltration furnace, and Hf10Si2B alloy was added to the furnace. The temperature of the furnace was set to 1950℃, and vacuum metal infiltration of the carbon-carbon preform was started to obtain a ceramic matrix composite material (HQBZ / 30SiC / T300-S1mm / Hf10Si2B-CMC).

[0102] Example 4:

[0103] Toluene was added to the reactor, and then aniline was added under stirring. After the aniline was added, paraformaldehyde was added in batches. After all the paraformaldehyde was added, the mixture was reacted at room temperature for 2 hours. Then, catechol was added to the mixture, and the temperature was raised to 90°C and reacted for 8 hours. After the reaction was completed, the water in the system was separated and then washed three times with NaOH aqueous solution. Finally, the material was washed with pure water until the pH was neutral. After separation and drying, the solvent was removed by rotary evaporation to obtain the organic resin.

[0104] The temperature of the reactor was raised to 115°C, and N,N-dimethylacetamide was added to the reactor containing the organic resin, so that the organic resin was completely dissolved in N,N-dimethylacetamide to obtain an organic solution with a mass concentration of 10%.

[0105] Then, short-cut silicon carbide fiber (SiC-S10mm) powder with a particle size of 10mm was selected, and the mass ratio of the organic solvent to the short-cut silicon carbide fiber (SiC-S10mm) powder with a particle size of 10mm was 1:0.2.

[0106] Short-cut silicon carbide fiber (SiC-S10mm) powder with a length of 10mm was added at a constant speed to a reaction vessel containing an organic solvent and mechanically stirred to uniformly disperse the 10mm-length short-cut silicon carbide fiber (SiC-S10mm) powder in the organic solvent, thus obtaining a liquid premix.

[0107] Measure N,N-dimethylacetamide and deionized water, with a mass ratio of N,N-dimethylacetamide to deionized water of 1:0.8. Mix the deionized water with N,N-dimethylacetamide to prepare a precipitant. Then, add the precipitant to the reactor containing the liquid premix at a rate of 1.5 wt% / min, and stir at a constant speed during the addition of the precipitant to obtain resin-coated wet powder.

[0108] Deionized water was added to the reactor containing the resin-coated wet powder, with a weight ratio of deionized water to resin-coated wet powder of 2:1. After raising the temperature of the reactor to 80°C and stirring and soaking for 3 hours, the material in the reactor was transferred to a centrifuge. The liquid and powder in the material were separated by centrifugation to obtain water-washed powder. The above operation was repeated 3 times. The content of the dissolved liquid in the water-washed powder was then checked to see if it was less than 2%. If the test result showed that the content of the dissolved liquid was less than 2%, the water washing was stopped; if the test result showed that the content of the dissolved liquid was greater than 2%, the water washing operation was continued until the test result showed that the content of the dissolved liquid was less than 2%.

[0109] The water-washed powder with a content of less than 2% in the solution, as shown by the test results, was transferred to a fluidized bed. The temperature of the fluidized bed was set to 90℃, and the water-washed powder was dried until it reached a constant weight, thus obtaining resin-coated powder (CaBZ / SiC-S10mm).

[0110] The resin-coated powder (CaBZ / SiC-S10mm) is transferred into a vacuum press, and the hot pressing pressure is set to 0.2MPa and the temperature is 210℃. The resin-coated powder (CaBZ / SiC-S10mm) is cured and molded to obtain a resin blank.

[0111] The resin blank is placed in a carbonization furnace, and the temperature of the carbonization furnace is raised to 800℃ for carbonization treatment to obtain a carbon-carbon blank.

[0112] The carbon-carbon preform was transferred to a metal infiltration furnace, and SiZr10 alloy was added to the furnace. The temperature of the metal infiltration furnace was set to 1600℃, and the carbon-carbon preform underwent vacuum metal infiltration to obtain a ceramic matrix composite material (CaBZ / SiC-S10mm / SiZr10-CMC).

[0113] Example 5:

[0114] Toluene was added to the reactor, and then aniline was added under stirring. After the aniline was added, paraformaldehyde was added in batches. After all the paraformaldehyde was added, the mixture was reacted at room temperature for 2 hours. Then, catechol was added to the mixture, and the temperature was raised to 90°C and reacted for 8 hours. After the reaction was completed, the water in the system was separated and then washed three times with NaOH aqueous solution. Finally, the material was washed with pure water until the pH was neutral. After separation and drying, the solvent was removed by rotary evaporation to obtain the organic resin.

[0115] The temperature of the reactor was raised to 115°C, and N,N-dimethylacetamide was added to the reactor containing the organic resin, so that the organic resin was completely dissolved in N,N-dimethylacetamide to obtain an organic solution with a mass concentration of 10%.

[0116] Then, 10mm short-cut carbon fiber T300 (T300-S10mm) powder was selected, and the mass ratio of the organic solvent to the 10mm short-cut carbon fiber T300 (T300-S10mm) powder was 1:0.2.

[0117] Short-cut carbon fiber T300 (T300-S10mm) powder with a length of 10mm was added at a constant speed to a reaction vessel containing an organic solvent and mechanically stirred to uniformly disperse the 10mm-length short-cut carbon fiber T300 (T300-S10mm) powder in the organic solvent, thus obtaining a liquid premix.

[0118] Measure N,N-dimethylacetamide and deionized water, with a mass ratio of N,N-dimethylacetamide to deionized water of 1:0.8. Mix the deionized water with N,N-dimethylacetamide to prepare a precipitant. Then, add the precipitant to the reactor containing the liquid premix at a rate of 1.5 wt% / min, and stir at a constant speed during the addition of the precipitant to obtain resin-coated wet powder.

[0119] Deionized water was added to the reactor containing the resin-coated wet powder, with a weight ratio of deionized water to resin-coated wet powder of 2:1. After raising the temperature of the reactor to 80°C and stirring and soaking for 3 hours, the material in the reactor was transferred to a centrifuge. The liquid and powder in the material were separated by centrifugation to obtain water-washed powder. The above operation was repeated 3 times. The content of the dissolved liquid in the water-washed powder was then checked to see if it was less than 2%. If the test result showed that the content of the dissolved liquid was less than 2%, the water washing was stopped; if the test result showed that the content of the dissolved liquid was greater than 2%, the water washing operation was continued until the test result showed that the content of the dissolved liquid was less than 2%.

[0120] The water-washed powder with a content of less than 2% as shown by the test results was transferred to a fluidized bed. The temperature of the fluidized bed was set to 90℃, and the water-washed powder was dried until the water-washed powder reached a constant weight, thus obtaining resin-coated powder (CaBZ / T300-S10mm).

[0121] The resin-coated powder (CaBZ / T300-S10mm) is transferred into a vacuum press, and the hot pressing pressure is set to 2.0MPa and the temperature is 220℃. The resin-coated powder (CaBZ / T300-S10mm) is cured and molded to obtain a cured resin blank.

[0122] The resin blank is placed in a carbonization furnace, and the temperature of the carbonization furnace is raised to 800℃ for carbonization treatment to obtain a carbon-carbon blank.

[0123] The carbon-carbon preform was transferred to a metal infiltration furnace, and SiZr10 alloy was added to the furnace. The temperature of the furnace was set to 1500℃, and vacuum metal infiltration of the carbon-carbon preform was started to obtain a ceramic matrix composite material (CaBZ / T300-S10mm / SiZr10-CMC).

[0124] See Figure 2 and Figure 3 , Figure 2 The image shows a microscopic image of the powder used to coat SiC ceramic composite matrix material with organic resin during the preparation process of this embodiment 2. The image shows the powder used to coat SiC ceramic composite matrix material with organic resin and reinforcing fibers such as carbon fiber and silicon carbide with a length of 3 mm. Figure 3 The image shows a microscopic image of the powder for SiC ceramic matrix composite materials prepared by crushing. The image shows short chopped fibers with a length of only 20-60 μm, which are longer than the short chopped fibers prepared in this invention.

[0125] See Figure 4 The figure shows the flexural stress-strain curves of SiC ceramic matrix composite powders prepared with 50μm and 5mm carbon fibers. From the two comparative curves, it is clear that the flexural strength of the SiC ceramic matrix composite prepared with 50μm Cf is 174.01 MPa, and the fracture microstrain is 1.12. In contrast, the flexural strength of the SiC matrix composite prepared with 5mm Cf is 232.08 MPa, and the fracture microstrain is 3.72. Compared to the 5mm Cf, the SiC ceramic matrix composite prepared using the longer fibers of this invention exhibits significantly improved strength and toughness.

[0126] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0127] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. 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 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 SiC ceramic matrix composite materials, characterized in that, Includes the following steps: S1, Dissolve the organic resin in the solvent to obtain an organic solvent with a mass concentration of 10-50%; S2, the organic solvent and inorganic powder are mixed and stirred to disperse evenly to obtain a liquid premix; wherein the inorganic powder contains short chopped fibers with a length between 3 and 10 mm; the mass ratio of the organic solvent to the inorganic powder is 1:(0.1~0.4). S3, a precipitant is added to the liquid premix to precipitate and obtain resin-coated wet powder; wherein the precipitant is obtained by mixing the solution and deionized water at a mass ratio of 1:(0.3~0.8), and the addition rate of the precipitant is 0.5wt%-2wt% / min. S4, the wet powder is washed with water and dried in sequence to obtain resin-coated powder; S5, the resin-coated powder is sequentially subjected to hot pressing, carbonization, and metal infiltration to obtain SiC ceramic matrix composite material.

2. The method for preparing a SiC ceramic matrix composite material according to claim 1, characterized in that, The solvent mentioned in S1 is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, sulfolane, and N-methylpyrrolidone.

3. The method for preparing a SiC ceramic matrix composite material according to claim 1, characterized in that, The washing and drying processes described in S4 are as follows: Deionized water and wet powder were loaded into a reaction vessel at a weight ratio of 2 to 3:

1. The temperature in the reaction vessel was adjusted to 60 to 100°C. After stirring and soaking for 2 to 3 hours, the powder was separated using a centrifuge to obtain the washed powder. The washed powder was placed on a fluidized bed at a temperature of 60~100℃ until constant weight was obtained to obtain resin-coated powder.

4. The method for preparing a SiC ceramic matrix composite material according to claim 1, characterized in that, The hot pressing molding described in S5 is selected from either compression molding or autoclave molding; the carbonization temperature is 800~1500℃.

5. The method for preparing a SiC ceramic matrix composite material according to claim 1, characterized in that, The metal selected for metal infiltration as described in S5 is one or more of elemental Si, Si-Zr alloy, Hf-Si-B alloy, or Hf-Zr-Si-Ta alloy; the metal infiltration temperature is 1500~2000℃.

6. A SiC ceramic matrix composite material, characterized in that, The SiC ceramic matrix composite material was prepared using any one of claims 1 to 5.

7. The SiC ceramic matrix composite material described in claim 6 is used in the preparation of space mirror supports and chemical heat exchangers.

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