A ceramic matrix composite with modified silicon carbide as the precursor and its preparation method

Abstract

The present invention discloses a ceramic matrix composite material with modified silicon carbide as the precursor and a preparation method thereof, belonging to the technical field of ceramic matrix composite materials. The ceramic matrix composite material includes coarse SiC powder, modified fine SiC powder, SiC fibers, deionized water and a pH regulator; the solid phase content of the ceramic matrix composite material is 40-70 vol%; by using the modified fine SiC powder, an RSiC green body with a uniform microstructure is obtained, so that the obtained ceramic matrix composite material has better thermal shock resistance and high temperature strength, and the modified fine SiC powder has good dispersibility and stability in the solution.

Description

Technical Field

[0001] The present invention belongs to the technical field of ceramic matrix composites, and particularly relates to a ceramic matrix composite with modified silicon carbide as a precursor and a preparation method thereof. Background Art

[0002] Silicon carbide (SiC) ceramics play an important role in high-temperature structural ceramics due to their low coefficient of thermal expansion, high thermal conductivity, high hardness, good thermal stability and chemical stability, etc., and are widely used in the fields of aerospace, nuclear energy, military and semiconductors. Due to the extremely strong covalent bonds and extremely low diffusion coefficient of SiC, it is very difficult to fully densify SiC ceramics. Therefore, a variety of sintering technologies for SiC ceramics have been developed, including reaction sintering, pressureless solid-phase sintering, pressureless liquid-phase sintering, hot-pressing sintering and recrystallization sintering, etc.

[0003] SiC ceramics prepared by the recrystallization sintering technology are called recrystallized silicon carbide ceramics (RSiC). Compared with SiC ceramics prepared by other sintering processes, RSiC has the advantages of high purity, pure crystal phase and no impurity phase, etc., and thus has better thermal shock resistance and high-temperature strength. At present, compared with foreign high-performance RSiC ceramics, the density and performance of domestic RSiC ceramics still need to be improved. The overall performance of RSiC ceramics is directly related to the density and microstructure of their green bodies. Usually, methods such as surface modification of ultrafine SiC powder, adjustment of powder particle size distribution and optimization of forming process are used to improve the density of RSiC green bodies. Ultrafine SiC powder usually has a large number of aggregates, which has an adverse effect on the density and microstructure uniformity of the green body. Therefore, it is necessary to perform surface modification on ultrafine SiC powder, which is also the most effective method to improve the density of RSiC green bodies. At present, the modification of SiC fine powder mainly includes surface coating modification and surface chemical modification. Surface coating modification is to mix ultrafine powder and modifier in water or organic medium according to a certain ratio, and the modifier is adsorbed on the particle surface through intermolecular forces such as hydrogen bonds or electrostatic attraction, and forms a monolayer or multilayer coating on the particle surface, but this supramolecular interaction is weak; surface chemical modification is to make the modifier coat or graft on the powder surface by chemical reaction or chemical adsorption between the modifier and the functional groups on the powder surface, so as to improve the surface properties of powder particles. Among them, silane coupling agent is the most commonly used coupling agent and is widely used as a surface modifier for ceramic powder. However, when using silane coupling agent, on the one hand, the reaction degree with the surface of silicon carbide is limited and the effect is poor, and on the other hand, the coupling agent itself will condense, resulting in an increase in the viscosity of the slurry. Summary of the Invention

[0004] In order to overcome the deficiencies of the above-mentioned existing technologies, the present invention provides a ceramic matrix composite material with modified silicon carbide as a precursor. By modifying SiC fine powder, a green body of RSiC with a uniform microstructure is obtained, so that the obtained ceramic matrix composite material has better thermal shock resistance and high-temperature strength, and the modified SiC fine powder has good dispersibility and stability in the solution.

[0005] The technical solution for achieving the purpose of the present invention is as follows:

[0006] A ceramic matrix composite material with modified silicon carbide as a precursor, the ceramic matrix composite material includes SiC coarse powder, modified SiC fine powder, SiC fibers, deionized water and a pH regulator;

[0007] The mass ratio of the SiC coarse powder, modified SiC fine powder and SiC fibers is (4-9):(1-7):(0-5), and the solid content of the ceramic matrix composite material is 40-70 vol%;

[0008] The preparation method of the modified SiC fine powder is as follows: at 0-5 °C, the modifier is dispersed in ethanol, and SiC fine powder is added while stirring, and then deionized water is added. After adjusting the pH of the solution to 8-10, it is stirred at 20-50 °C for at least 1 h, filtered, washed with ethanol at least 2 times, dried and ground to obtain the modified SiC fine powder;

[0009] The modifier has the following polymer molecular structure of formula I:

[0010] , in formula I, R1, R2 and R3 are at least one of methyl and hydrogen; R4, R5 and R6 are at least one of methyl and ethyl; R7 is a quaternary ammonium salt structure; the ratio of a, b and c is (5-20):(20-70):(5-30); X is one or several of F, Cl, Br and I; the modifier is obtained by free radical polymerization of the monomers corresponding to the polymer in formula I.

[0011] Preferably, the particle size of the SiC coarse powder is 10-350 μm, the particle size of the SiC fine powder is 0.01-10 μm, and the pH regulator is one or several of sodium hydroxide, sodium bicarbonate and sodium carbonate; in formula I, n is 20-100; m is 1 to 10; the diameter of the SiC fiber is 5-10 μm, and the length is 50-100 μm.

[0012] More preferably, the preparation method of the SiC fiber is as follows:

[0013] The polycarbosilane is heated to a molten state, extruded into fibers through a spinneret, and then thermally oxidized and cured. After heat treatment at a temperature of 1200-1500 °C in an inert atmosphere, SiC fibers are obtained.

[0014] Preferably, in the preparation method of the modified SiC fine powder, the content of the modifier is 0.8 wt% - 2.0 wt% of ethanol and deionized water, the content of the SiC fine powder is 40 - 60 vol% of ethanol and deionized water, and the volume ratio of ethanol to water is (5 - 7):(3 - 5).

[0015] Preferably, the preparation method of the modifier is as follows:

[0016] Disperse the monomer, initiator and cuprous compound in the solvent in a Schlenk flask under an inert gas atmosphere. After freeze-thaw degassing, add the ligand and stir at 50 - 80 °C for 1 - 5 h. After the reaction is completed, pass oxygen to terminate the reaction. Remove copper ions by column chromatography. After concentrating the solution, precipitate in cold methanol, filter, collect the solid product and dry it to obtain the modifier.

[0017] Preferably, the molar ratio of the monomer, initiator, cuprous compound and ligand is: (80 - 120):(0.5 - 2):(0.7 - 2.2):(0.8 - 2.5); the initiator is one or more of ethyl 2-bromo-2-methylpropionate, ethyl 2-chloro-2-methylpropionate, methyl 2-bromo-2-methylpropionate, methyl 2-chloro-2-methylpropionate and ethyl chloroacetate; the ligand is at least one of N,N,N’,N’-tetramethylethylenediamine, 1,1,4,7,7-penta(methyl methacrylate)-divinyltriamine, 1,1,4,7,10,10-hexa(n-butyl methacrylate)-trivinyltetramine, 2,2’-bipyridine, 1,1,4,7,7-penta(methyl)-divinyltriamine, 1,1,4,7,10,10-hexa(methyl methacrylate)-trivinyltetramine; the cuprous compound is at least one of cuprous bromide and cuprous chloride; the solvent is at least one of toluene and anisole.

[0018] Preferably, the monomer is a siloxane monomer, a polyether monomer and a quaternary ammonium salt monomer, and the molar ratio is (5 - 20):(20 - 70):(5 - 30); the preparation method of the quaternary ammonium salt monomer is as follows:

[0019] S1. Disperse 1.0 eq of an amine compound and 1.0 eq of a chloroalcohol compound or a bromoalcohol compound in toluene. Under a nitrogen atmosphere, stir at 40 - 90 °C for 16 - 36 h, cool to room temperature, filter, and wash the obtained solid with ether and acetonitrile at least 2 times, and dry it under vacuum to obtain the quaternary ammonium salt monomer precursor.

[0020] S2. Disperse 1.0 eq of quaternary ammonium salt monomer precursor and 1.5 - 2.5 eq of acryloyl chloride or methacryloyl chloride in anhydrous dichloromethane. Under a nitrogen atmosphere, stir for 8 - 16 h. After the reaction is completed, wash with 1 - 2 mol / L sodium hydroxide and hydrochloric acid solution at least 2 times in sequence. Collect the organic phase, remove the solvent, and obtain the quaternary ammonium salt monomer;

[0021] The amine compound is one or more of trimethylamine, triethylamine, N,N - dimethylaniline and its derivatives, pyridine and its derivatives;

[0022] The chlorohydrin compound is one or more of 2 - chloroethanol, 3 - chloropropanol, 4 - chlorobutanol, 5 - chloropentanol;

[0023] The bromohydrin compound is one or more of 2 - bromoethanol, 3 - bromopropanol, 4 - bromobutanol, 5 - bromopentanol.

[0024] The present invention also discloses a preparation method of the above - mentioned ceramic - matrix composite material with modified silicon carbide as the precursor, including the following steps:

[0025] (1) Preparation of green body: Mix SiC coarse powder, modified SiC fine powder, SiC fiber and deionized water to prepare a slurry. After adjusting the pH of the slurry to 9 - 11 with a pH regulator, stir mechanically for 4 - 8 h. Inject the uniformly mixed slurry into a mold for molding. After the slurry is cured, take out the green body and dry it;

[0026] (2) Firing: Keep the green body at 500 - 700 °C under an inert atmosphere protection for 2 - 3 h to remove organic substances, and sinter at 2000 - 2450 °C under an inert atmosphere protection for 8 - 10 h. Fine particles gradually evaporate into gas phase and condense at the contact of coarse particles to form the ceramic - matrix composite material.

[0027] Beneficial effects

[0028] The present invention has the following beneficial effects: It provides a ceramic matrix composite with modified silicon carbide as the precursor. By modifying the SiC fine powder, a high-density and microstructurally uniform RSiC green body is obtained, enabling the resulting ceramic matrix composite to have more excellent thermal shock resistance and high-temperature strength. A modifier is used to modify the SiC fine powder. The structure of the modifier contains polyether and quaternary ammonium salt structures. Through electrostatic repulsion and steric hindrance effects, it can be evenly dispersed in the solution to prevent self-crosslinking. The modifier and the SiC fine powder are initially dispersed in an alcohol solution. At this time, the amide group of the modifier is initially adsorbed on the SiC fine powder through hydrogen bonding with the silanol groups of the SiC fine powder. Then, at low temperature, an aqueous solution is added and the pH is increased. The silanol is converted into a silanol anion, which adsorbs the quaternary ammonium salt structure on the modifier through an ionic bond. At this time, most of the modifier has been adsorbed on the SiC fine powder. After heating, the siloxane of the modifier hydrolyzes and couples with the SiC fine powder. The modifier uses a polymer structure to modify the SiC fine powder, with a denser coverage, multi-point binding, good stability, a better steric hindrance effect, and better dispersion performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the synthesis and structure of the modifier of the present invention;

[0030] Figure 2 It is a schematic diagram of the mechanism of action between the modifier and the SiC fine powder of the present invention;

[0031] Figure 3 It is a nuclear magnetic hydrogen spectrum diagram of modifier 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0033] In the embodiments, the experimental methods used are all conventional methods unless otherwise specified, and the materials, reagents, etc. used can be obtained from commercial channels unless otherwise specified.

[0034] Now, the raw materials and equipment used in the examples and comparative examples are described as follows:

[0035] SiC coarse powder: D 50 = 20 μm, purity ≥ 99.9 wt.%;

[0036] SiC fine powder: D 50 = 0.5 μm, purity ≥ 99.9 wt.%;

[0037] SiC fibers: with a diameter of 5 - 10 μm and a length of 50 - 100 μm;

[0038] Initiator: ethyl chloroacetate, Aladdin Shanghai;

[0039] Ligand: 1,1,4,7,7 - penta(methyl)-divinyltriamine, Macklin Shanghai;

[0040] Copper(I) chloride: Aladdin Shanghai;

[0041] Quaternary ammonium salt monomer precursor: choline chloride, Aladdin Shanghai;

[0042] Acryloyl chloride: Aladdin Shanghai;

[0043] 3 - triethoxysilylpropyltrimethylammonium chloride: Aladdin Shanghai;

[0044] 3 - aminopropyltriethoxysilane: Aladdin Shanghai;

[0045] Monomethyl polyethylene glycol: with an average molecular weight M n = 1000, Macklin Shanghai;

[0046] Quaternary ammonium salt monomer

[0047] Disperse 1.0 eq of the quaternary ammonium salt monomer precursor and 2.0 eq of acryloyl chloride in anhydrous dichloromethane, stir for 3 h under a nitrogen atmosphere. After the reaction, wash twice with 1 mol / L sodium hydroxide and hydrochloric acid solutions respectively, collect the organic phase, remove the solvent to obtain the quaternary ammonium salt monomer.

[0048] Siloxane monomer

[0049] Obtained by the acylation of acryloyl chloride and 3 - aminopropyltriethoxysilane under the catalysis of triethylamine.

[0050] Polyether monomer

[0051] Obtained by the acylation of acryloyl chloride and monomethyl polyethylene glycol under the catalysis of triethylamine.

[0052] Modifier 1

[0053] Disperse 10 eq of the siloxane monomer, 50 eq of the polyether monomer, 20 eq of the quaternary ammonium salt monomer, 0.8 eq of the initiator and 0.9 eq of copper(I) chloride in anisole in a Schlenk flask, perform freeze - thaw degassing, then add 1.0 eq of the ligand, stir at 80 °C for 3 h. After the reaction, pass oxygen to terminate the reaction, remove copper ions by column chromatography, concentrate the solution, precipitate in cold methanol, filter, collect the solid product and dry it to obtain Modifier 1.

[0054] Modifier 2

[0055] 60 eq of polyether monomer, 20 eq of quaternary ammonium salt monomer, 0.8 eq of initiator and 0.9 eq of cuprous chloride were dispersed in anisole in a Schlenk flask under a nitrogen gas atmosphere. After freeze-thaw degassing, 1.0 eq of ligand was added, and the mixture was stirred at 80 °C for 3 h. After the reaction was completed, oxygen was introduced to terminate the reaction. Copper ions were removed by column chromatography. After the solution was concentrated, it was precipitated in cold methanol, filtered, and the solid product was collected and dried to obtain modifier 2.

[0056] Modifier 3

[0057] Compared with the preparation method of modifier 1, the difference is that 20 eq of quaternary ammonium salt monomer is replaced by 20 eq of polyether monomer.

[0058] Modifier 4

[0059] Compared with the preparation method of modifier 1, the difference is that 50 eq of polyether monomer is replaced by 17 eq of siloxane monomer and 33 eq of quaternary ammonium salt monomer.

[0060] Modifier 5

[0061] Compared with the preparation method of modifier 1, the difference is that 10 eq of siloxane monomer, 50 eq of polyether monomer, and 20 eq of quaternary ammonium salt monomer are physically mixed.

[0062] Modifier 6

[0063] 3-aminopropyltriethoxysilane was used as modifier 6.

[0064] Modifier 7

[0065] 3-triethoxysilylpropyltrimethylammonium chloride was used as modifier 7.

[0066] The following are the test methods for the performance parameters involved in the present invention:

[0067] Molecular weight M w : The molecular weight was detected by the GPC method;

[0068] Slurry viscosity: Measured by a rotational viscometer at a rotational speed of 60 rpm;

[0069] Slurry stability: The SiC suspension with a solid content of 10 vol% was placed in a graduated cylinder, and the initial height (h0) of the suspension in the graduated cylinder and the height (h) of the supernatant in the graduated cylinder after sedimentation for three days were recorded. The stability of the SiC suspension was evaluated by the h / h0 ratio (%), and the smaller the value, the higher the stability of the suspension.

[0070] Flexural strength test: According to GB / T 6569-2006, using an electronic universal testing machine, the flexural strength of silicon carbide ceramic samples was tested by the three-point bending method.

[0071] Table 1 Molecular weight test of modifiers 1-4

[0072]

[0073] Modified SiC fine powder 1

[0074] At 0 °C, 8 g of modifier 1 was dispersed in 650 ml of ethanol. While stirring, a total of 50 vol% of SiC fine powder was added, and then 350 ml of deionized water was added. After adjusting the pH of the solution to 9, it was stirred at 35 °C for 2 h, filtered, washed twice with ethanol, dried and ground to obtain modified SiC fine powder 1.

[0075] Modified SiC fine powder 2

[0076] Compared with the preparation method of modified SiC fine powder 1, the difference is that 8 g of modifier 1 is replaced by 12 g.

[0077] Modified SiC fine powder 3

[0078] Compared with the preparation method of modified SiC fine powder 1, the difference is that 8 g of modifier 1 is replaced by 16 g.

[0079] Modified SiC fine powder 4

[0080] Compared with the preparation method of modified SiC fine powder 1, the difference is that 8 g of modifier 1 is replaced by 20 g.

[0081] Modified SiC fine powder 5

[0082] Compared with the preparation method of modified SiC fine powder 1, the difference is that 8 g of modifier 1 is replaced by 30 g.

[0083] Modified SiC fine powder 6

[0084] Compared with the preparation method of modified SiC fine powder 1, the difference is that the pH of the solution is adjusted to 5.

[0085] Modified SiC fine powder 7

[0086] Compared with the preparation method of modified SiC fine powder 1, the difference is that the pH of the solution is adjusted to 12.

[0087] Modified SiC fine powders 8-13

[0088] Compared with the preparation method of modified SiC fine powder 1, the difference is that modifier 1 is replaced by modifiers 2-7.

[0089] A preparation method of a ceramic matrix composite with modified silicon carbide as a precursor, comprising the following steps:

[0090] (1) Preparation of green body: Mix SiC coarse powder, modified SiC fine powder, SiC fiber and deionized water to prepare a slurry. After adjusting the pH of the slurry to 10 with a pH regulator, mechanically stir for 6 h, inject the uniformly mixed slurry into a mold for shaping. After the slurry solidifies, take out the green body and dry it;

[0091] (2) Firing: Keep the green body at 600 °C under an inert atmosphere for 3 h to remove organic substances, and sinter at 2300 °C under an inert atmosphere for 8 h to form a ceramic matrix composite.

[0092] Example 1

[0093] The mass ratio of SiC coarse powder, modified SiC fine powder 1 and SiC fiber is 6:4:2, and the solid content is 58%.

[0094] Examples 2 to 4

[0095] Compared with Example 1, the difference is that modified SiC fine powder 1 is replaced by modified SiC fine powders 2 to 4.

[0096] Comparative Example 1

[0097] Compared with Example 1, the difference is that the modified SiC fine powder is replaced by SiC fine powder.

[0098] Comparative Examples 2 to 10

[0099] Compared with Example 1, the difference is that modified SiC fine powder 1 is replaced by modified SiC fine powders 5 to 13.

[0100] Table 2 Performance tests of examples and comparative examples

[0101]

[0102] As can be seen from the data in Table 2, the performances of Examples 1 to 4 are all superior to those of the Comparative Examples. The slurry viscosities and stabilities of Examples 1 to 4 first increase and then decrease, and the flexural strengths of the ceramic matrix composites also first increase and then decrease. Because among the modified SiC powders 1 to 4, with the change in the content of the modifier, as the content of the modifier increases, the viscosity first decreases and then increases. Excessive modifiers will increase the probability of reaction between the modifiers in the solution, resulting in an increase in the slurry viscosity. From the data of Comparative Example 2, it can be seen that adding too much modifier will cause a significant increase in the viscosity of the slurry. From the data of Comparative Examples 3 to 4, it can be known that when modifying, too low or too high pH of the solution will affect the effect of the modifier on the SiC powder. When the pH is too low, the silanol groups in the solution are protonated, resulting in a positive charge on the surface of the SiC powder. At this time, it will be mutually exclusive with the quaternary ammonium salt ions, resulting in a decrease in the reaction probability between the silane coupling agent and it; when the pH is too high, it will cause the siloxane in the modifier to hydrolyze rapidly and crosslink itself. From the data of Comparative Examples 4 to 7, it can be seen that the three monomer molecular structures complement each other, and the lack of any component will lead to a decrease in the performances of the slurry and the ceramic. From the data of Comparative Example 8, it can be seen that for simple physical blending, either the dispersion of a single structure is poor, or the interaction between the SiC powders is small, and it cannot effectively improve the performance, and the crosslinking between the components may further increase the viscosity of the slurry. From Comparative Example 9, it can be seen that under alkaline conditions, 3-aminopropyltriethoxysilane plays a small role in modifying the SiC powder. At this time, the amino group does not carry a positive charge, has a weak interaction with the SiC powder, and is prone to crosslinking itself, resulting in a poor modification effect. From the data of Comparative Example 10, it can be seen that although using 3-triethoxysilylpropyltrimethylammonium chloride as a modifier can play a certain role, the effect is not as good as that of the present invention. First, there is no steric hindrance effect of the polyether structure. Second, when small molecules are modified, the coverage is not as dense as that of the polymer structure, and the multi-point binding is not as stable.

[0103] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A ceramic matrix composite with modified silicon carbide as the precursor, characterized in that, The ceramic matrix composite material comprises SiC coarse powder, modified SiC fine powder, SiC fibers, deionized water and a pH regulator; The mass ratio of the SiC coarse powder, the modified SiC fine powder and the SiC fibers is (4 - 9):(1 - 7):(0 - 5), and the solid content of the ceramic matrix composite material is 40 - 70 vol%; The preparation method of the modified SiC fine powder is as follows: At 0 - 5 °C, the modifier is dispersed in ethanol, and while stirring, SiC fine powder is added, then deionized water is added. After adjusting the pH of the solution to 8 - 10, it is stirred at 20 - 50 °C for at least 1 h, then filtered, washed with ethanol at least 2 times, dried and ground to obtain the modified SiC fine powder; The modifier has the polymer molecular structure of formula I as follows: In Formula I, at least one of R1, R2, and R3 is methyl or hydrogen; at least one of R4, R5, and R6 is methyl or ethyl; R7 is a quaternary ammonium salt structure; the ratio of a, b, and c is (5 - 20) : (20 - 70) : (5 - 30); X is one or more of F, Cl, Br, and I; the modifier is obtained by free radical polymerization of the monomers corresponding to the polymer in Formula I; In the preparation method of the modified SiC fine powder, the content of the modifier is 0.8 wt% - 2.0 wt% of ethanol and deionized water, the content of the SiC fine powder is 40 - 60 vol% of ethanol and deionized water, and the volume ratio of ethanol to water is (5 - 7):(3 - 5).

2. The ceramic matrix composite material with modified silicon carbide as the precursor according to claim 1, characterized in that, The particle size of the SiC coarse powder is 10 - 350 μm, the particle size of the SiC fine powder is 0.01 - 10 μm, the pH regulator is one or more of sodium hydroxide, sodium bicarbonate and sodium carbonate; in formula I, n is 20 - 100; m is 1 to 10; the diameter of the SiC fiber is 5 - 10 μm, and the length is 50 - 100 μm.

3. The ceramic matrix composite material with modified silicon carbide as the precursor according to claim 1, characterized in that, The preparation method of the modifier is as follows: The monomer, initiator and cuprous compound are dispersed in the solvent in a Schlenk flask under an inert gas atmosphere. After freeze-thaw degassing, the ligand is added, and it is stirred at 50 - 80 °C for 1 - 5 h. After the reaction is completed, oxygen is introduced to terminate the reaction. The copper ions are removed by column chromatography. After the solution is concentrated, it is precipitated in cold methanol, filtered, and the solid product is collected and dried to obtain the modifier.

4. The ceramic matrix composite material with modified silicon carbide as the precursor according to claim 3, characterized in that, The molar ratio of the monomer, initiator, cuprous compound and ligand is: (80 - 120):(0.5 - 2):(0.7 - 2.2):(0.8 - 2.5); the initiator is one or more of ethyl 2-bromo-2-methylpropionate, ethyl 2-chloro-2-methylpropionate, methyl 2-bromo-2-methylpropionate, methyl 2-chloro-2-methylpropionate and ethyl chloroacetate; the ligand is at least one of N,N,N',N'-tetramethylethylenediamine, 1,1,4,7,7-penta(methyl methacrylate)-divinyltriamine, 1,1,4,7,10,10-hexa(n-butyl methacrylate)-triethylenetetramine, 2,2'-bipyridine, 1,1,4,7,7-penta(methyl)-divinyltriamine, 1,1,4,7,10,10-hexa(methyl methacrylate)-triethylenetetramine; the cuprous compound is at least one of cuprous bromide and cuprous chloride; the solvent is at least one of toluene and anisole.

5. The ceramic matrix composite material with modified silicon carbide as the precursor according to claim 1, characterized in that, The monomer is a siloxane monomer, a polyether monomer and a quaternary ammonium salt monomer, and the molar ratio is (5 - 20):(20 - 70):(5 - 30); the preparation method of the quaternary ammonium salt monomer is as follows: S1. Disperse 1.0 eq of an amine compound and 1.0 eq of a chloroalcohol compound or a bromoalcohol compound in toluene. Under a nitrogen atmosphere, stir at 40 - 90 °C for 16 - 36 h. Cool to room temperature, filter, and wash the obtained solid with ether and acetonitrile at least 2 times each. Dry under vacuum to obtain the quaternary ammonium salt monomer precursor. S2. Disperse 1.0 eq of the quaternary ammonium salt monomer precursor and 1.5 - 2.5 eq of acryloyl chloride or methacryloyl chloride in anhydrous dichloromethane. Under a nitrogen atmosphere, stir for 8 - 16 h. After the reaction is completed, wash with 1 - 2 mol / L sodium hydroxide and hydrochloric acid solution at least 2 times each. Collect the organic phase, remove the solvent, and obtain the quaternary ammonium salt monomer. The amine compound is one or more of trimethylamine, triethylamine, N,N - dimethylaniline and its derivatives, pyridine and its derivatives. The chloroalcohol compound is one or more of 2 - chloroethanol, 3 - chloropropanol, 4 - chlorobutanol, 5 - chloropentanol. The bromoalcohol compound is one or more of 2 - bromoethanol, 3 - bromopropanol, 4 - bromobutanol, 5 - bromopentanol.

6. The preparation method of a ceramic matrix composite material using modified silicon carbide as a precursor according to any one of claims 1 to 5, characterized in that, It includes the following steps: (1) Preparation of green body: Mix SiC coarse powder, modified SiC fine powder, SiC fiber and deionized water to prepare a slurry. After adjusting the pH of the slurry to 9 - 11 with a pH regulator, stir mechanically for 4 - 8 h. Inject the uniformly mixed slurry into a mold for shaping. After the slurry solidifies, take out the green body and dry it. (2) Firing: Keep the green body at 500 - 700 °C under an inert atmosphere for 2 - 3 h to remove organic substances, and sinter at 2000 - 2450 °C under an inert atmosphere for 8 - 10 h to form a ceramic matrix composite.

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