CN112266259B

CN112266259B - Ceramic matrix composite material and preparation method and application thereof

Info

Publication number: CN112266259B
Application number: CN202011056586.5A
Authority: CN
Inventors: 龙宪海; 周峰; 匡湘铭; 汪莉; 何家琪; 王成华
Original assignee: Zhongjing Jitai Beijing Technology Co ltd
Current assignee: Mouhang (Daishan) Carbon Ceramics Co.,Ltd.
Priority date: 2020-09-29
Filing date: 2020-09-29
Publication date: 2021-07-27
Anticipated expiration: 2040-09-29
Also published as: CN112266259A

Abstract

The invention discloses a ceramic matrix composite material and a preparation method and application thereof, wherein the ceramic matrix composite material comprises the following components in percentage by mass: 20 to 30 percent of carbon fiber, 20 to 40 percent of CVD-C, 10 to 25 percent of CVD-SiC, 5 to 25 percent of PIP-SiC, 5 to 15 percent of GSI-SiC, 5 to 15 percent of TiC and less than 3 percent of residual Si. The preparation method sequentially comprises the steps of depositing a C layer on a carbon fiber preform, depositing a SiC layer, preparing SiC by dipping and cracking a precursor, dipping pitch-carbonizing, preparing TiC and gas-phase siliconizing. The ceramic matrix composite material has the advantages of excellent frictional wear performance, mechanical property and thermal property, the content of each component can be flexibly designed and adjusted according to actual requirements, and the requirements of the fields of high-performance braking and aerospace structural members on the material performance are met.

Description

Ceramic matrix composite material and preparation method and application thereof

Technical Field

The invention belongs to the field of composite material preparation, relates to a ceramic matrix composite material, and a preparation method and application thereof, and particularly relates to a low-residual Si composite material containing multiple ceramic matrixes, and a preparation method and application thereof.

Background

With the rapid development of economic technology, a great deal of research on the preparation technology and application of C/C-SiC composite materials is developed at home and abroad in recent years. The C/C-SiC ceramic composite material has the advantages of low density, thermal shock resistance, wear resistance, corrosion resistance, oxidation resistance, insensitivity of friction performance to external environment media (such as mould, oil stain, moisture and the like), long service life and the like. The C/C-SiC ceramic composite material is used as a main heat-proof material, combines the basic advantages of carbon fiber and silicon carbide, and is widely applied to the fields of aviation, aerospace and the like. Particularly, the composite material has great potential in special parts which need to bear extremely high temperature, and have serious ablation resistance and scour resistance on aerospace aircrafts. Meanwhile, the carbon-ceramic (C/C-SiC) brake material has excellent friction and wear properties, is a novel brake material developed in recent years, and has wide application prospects in the high-energy brake field of high-speed trains, airplanes and the like. The railway as an important transportation method must face the challenge of efficiency, and speed increase is the optimal method for improving the railway operation efficiency, so that the speed per hour of a high-speed train of more than 300km/h becomes the inevitable trend of railway development. The increase in train operating speed poses a significant challenge to its safety, requiring that the performance of the important safety systems of the train must be substantially increased. The performance of a brake system of a train is more and more emphasized as an important guarantee of the running safety of the train, and the improvement of the performance of a brake material of a high-speed train and the reduction of the specific gravity of the brake material are necessary ways for further realizing the high-speed and light-weight of the high-speed train. Carbon-ceramic composite materials have become a research hotspot for replacing traditional friction materials.

SiC is a main matrix component of carbon ceramic materials, and SiC is introduced into the materials, and generally there are a Chemical Vapor Deposition (CVD) method, a Precursor impregnation-pyrolysis (PIP) method, a Liquid Silicon Infiltration (LSI) method, or a Gas Silicon Infiltration (GSI) method. Different methods for introducing SiC into the material have different modes, and although the performance of the material can be improved to a certain extent, different defects exist, for example, SiC prepared by a CVD process has a low friction coefficient, SiC prepared by a PIP process has a weak bonding force with other components, SiC is easy to fall off in the using process, and SiC prepared by an LSI process or a GSI process has large abrasion in the friction process. Chinese patent document CN109372916A discloses a method for preparing a ceramic reinforced carbon/carbon composite brake disc. The preparation process comprises the steps of putting the carbon fiber preform into a deposition furnace, depositing carbon by adopting a chemical vapor infiltration process, then carrying out an impregnation-carbonization process by using liquid-phase resin or liquid-phase pitch to obtain a carbon/carbon composite brake disc blank, carrying out liquid-phase siliconizing treatment on the blank, and carrying out mechanical processing to finally obtain the ceramic reinforced carbon/carbon composite brake disc. The SiC prepared by the process has single type, large crystal grains which are all prismatic, and large abrasion. Chinese patent document CN106064951B discloses a C/C-SiC composite material and a method for preparing the same, which comprises introducing matrix carbon on a carbon fiber preform, depositing a SiC layer by chemical vapor deposition, and reacting silicon vapor with carbon by using a gas phase siliconizing sintering process (GSI process) to form SiC (hereinafter referred to as GSI-SiC). However, in this patent document, the substrate carbon is covered with a SiC layer (CVD-SiC for short) produced by vapor deposition, and since the CVD-SiC layer is very dense and gaseous silicon cannot contact with the substrate carbon, the carbon source for carbon-silicon reaction is very small, and the reaction conditions are poor, so that the GSI-SiC content produced by carbon-silicon reaction is low, which is not favorable for improving the frictional wear performance of the material. The introduction of carbon silicon reaction carbon source in carbon ceramic material is carried out by pitch impregnation carbonization, resin impregnation-solidification-pyrolysis, chemical vapor deposition and the like. Patent CN102617178A discloses a preparation method of a C/SiC composite material, which mainly comprises the following steps: depositing SiC layer, impregnating pitch and carbonizing, and gas phase siliconizing. Because the difference between the physical and chemical properties of SiC and carbon fiber is large, the patent document uses a SiC layer to directly protect the carbon fiber, which can cause the poor performance of the interface between the two components and cause adverse effects on the mechanical properties of the material.

The carbon ceramic materials described in both of the above-mentioned patent documents CN102617178A and CN106064951B incorporate two types of SiC, including CVD-SiC and GSI-SiC. In the preparation process of the patent CN102617178A, a SiC layer is directly pyrolyzed and deposited on carbon fibers, the thickness of the CVD-SiC coating is not suitable to be too large, and the CVD-SiC layer is too thick and cracks due to mismatching of the layer and the carbon fibers, so that the proportion of the pyrolyzed and deposited SiC in the method is small, and the proportion cannot be adjusted and designed according to the friction and wear performance requirements. However, the preparation method disclosed in the patent CN106064951B application has no direct carbon source for carbon-silicon reaction, which results in difficult carbon-silicon reaction, and the amount of SiC generated by carbon-silicon reaction is small, so that it is difficult to obtain the required amount of GSI-SiC, so the patent application document also has a disadvantage that the ratio of two types of SiC phases cannot be adjusted and designed according to the material performance requirement.

The carbon ceramic material is also widely applied to heat-resistant structural members in the aerospace field, has potential in application to ultra-high temperature and ablation-resistant structural members, and has influence on the carbon ceramic material due to high-temperature and high-speed airflow in the ultra-high temperature ablation environment, so that the ablation resistance of the material can be improved through matrix modification. Chinese patent document CN104671815A discloses a method for preparing a ZrC-TiC modified C/C-SiC composite material, which comprises the steps of placing a C/C composite material blank containing a pyrolytic carbon layer on mixed powder containing Zr powder, Ti powder and Si powder, heating to 1900-2300 ℃ in a protective atmosphere, and then preserving heat to prepare the ZrC-TiC modified C/C-SiC composite material. However, in the preparation process, the temperature is high when the C/C material and the metal react, the carbon fiber is damaged at high temperature, the mechanical property of the material is reduced, the CVD-C layer is used as a carbon source for carbon-silicon reaction, Si atoms penetrate through the CVD-C layer and even reach the surface of the carbon fiber to cause fiber silicification damage, and in addition, the CVD-C layer is greatly lost, so that the amount of the CVD-C is reduced, the friction and wear performance is reduced, and therefore, the material prepared by the method is not suitable for the friction field. Chinese patent document CN109851381A discloses a method for infiltrating a C/C material by adopting a TiCu alloy, which comprises the steps of firstly pre-depositing a C matrix in pores of a C/SiC-ZrC composite material, then introducing the TiCu alloy through capillary adsorption, and introducing a new ultrahigh temperature phase TiC. The carbon fiber surface of the material prepared by the patent document has no matrix carbon, SiC and ZrC are used for directly protecting the carbon fiber, and the interface bonding performance between the carbon fiber and the components of SiC and ZrC is poor. The TiC crystal prepared by the reaction method is similar to LSI-SiC, the connection interface with CVD-C is poor, the connection strength is low, the abrasion is large, the TiC phase generated by the reaction is distributed and concentrated, the stability of the friction performance is not good, most residual pores are Cu metal simple substances, and the problem of high temperature resistance and limitation exists when the TiC crystal is applied to aerospace structural parts.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the ceramic matrix composite material which has excellent frictional wear performance, mechanical property and thermal property, contains various types of ceramic matrix components and can design and adjust the occupied proportion of the various types of ceramic matrix components, the preparation method and the application thereof, so that the comprehensive performance of the ceramic matrix composite material is more balanced to meet the requirements of the high-performance braking and aerospace structural member fields on the material performance.

In order to solve the technical problems, the invention adopts the following technical scheme.

The ceramic matrix composite material comprises the following components in percentage by mass:

in the components of the ceramic matrix composite, the residual Si is usually 0.5 to 3 percent, namely:

in the above ceramic matrix composite, preferably, the density of the ceramic matrix composite is 2.1g/cm³～2.5g/cm³The bending strength of the ceramic matrix composite material is not less than 350MPa, and the fracture toughness is not less than 10 MPa-m^1/2The thermal conductivity of the ceramic matrix composite is more than or equal to 50 W.m^-1·K^-1The dynamic friction coefficient of the ceramic matrix composite is 0.3-0.5, the wear rate is less than or equal to 0.3 mu m/time, and the stable coefficient of the friction coefficient is more than or equal to 0.85.

More preferably, the ceramic matrix composite material has a flexural strength of 350MPa to 570MPa and a fracture toughness of 10 MPa-m^1/2～14MPa·m^1/2The thermal conductivity of the ceramic matrix composite material is 50 W.m^-1·K^-1～85W·m^-1·K^-1。

As a general technical concept, the invention also provides a preparation method of the ceramic matrix composite material, which comprises the following steps:

(1) and C, deposition of a layer: depositing a carbon matrix in the carbon fiber preform by adopting a chemical vapor deposition method to obtain CVD-C and form a C/C blank;

(2) depositing a SiC layer: depositing a SiC layer on the surface of the obtained C/C blank by a chemical vapor deposition method to obtain CVD-SiC and form a C/C-SiC intermediate I;

(3) preparing SiC by dipping and cracking a precursor: placing the obtained C/C-SiC intermediate I in an impregnation solution for impregnation, wherein the impregnation solution is composed of polymethylsilane and xylene, curing the solution after impregnation, cracking the cured solution in a protective atmosphere to obtain PIP-SiC to form a C/C-SiC intermediate II, and repeating the impregnation-curing-cracking process when the required density cannot be achieved by primary impregnation-curing-cracking until the C/C-SiC intermediate II with the required density is obtained;

(4) impregnating pitch-carbonizing: immersing the obtained C/C-SiC intermediate II into the solution containing nano TiO₂The pitch is subjected to vacuum-pressure impregnation, the temperature is increased to melt the pitch after the vacuum is pumped, the pitch is impregnated under pressure to obtain a C/C-SiC intermediate II containing a pitch impregnating compound, the C/C-SiC intermediate II containing a pitch carbonized material is obtained by carbonizing the pitch after the pitch is cooled under the protection of inert atmosphere, and when the density of the pitch impregnated material is not required by primary pitch impregnation-carbonization, the pitch impregnation-carbonization process is repeated until the C/C-SiC intermediate II containing the pitch carbonized material with the required density is obtained;

(5) preparing TiC: heating the obtained C/C-SiC intermediate II containing the asphalt carbonized material in a flowing protective atmosphere to ensure that the nano TiO₂Reacting with asphalt carbon to generate TiC in situ to obtain a C/C-SiC material intermediate III containing dispersed TiC;

(6) gas-phase siliconizing: and carrying out gas-phase siliconizing on the obtained C/C-SiC material intermediate III containing the dispersed TiC under the vacuum condition to obtain GSI-SiC, and finally forming the C/C-SiC composite material containing the TiC and the three types of SiC, namely the ceramic matrix composite material.

In the above preparation method of the ceramic matrix composite, preferably, in the step (5), the protective atmosphere is nitrogen or argon, the heating temperature is 1450 ℃ to 1550 ℃, and the heating time is 15min to 30 min.

In the above method for preparing a ceramic matrix composite, preferably, in step (4), the vacuum-pressure impregnation method comprises the following steps: vacuumizing to less than 500Pa under a sealed condition, heating to melt asphalt after 20-40 min, stopping vacuumizing, pressurizing to 1.0-1.6 MPa by using protective gas, wherein the temperature of pressurizing and impregnating the asphalt is 200-220 ℃, and the time of pressurizing and impregnating the asphalt is 1-3 h; the carbonization temperature is 900-1200 ℃, and the carbonization time is 4-6 h.

Preferably, in the step (3), the mass ratio of xylene to polymethylsilane in the impregnation solution is 20-40: 100, the weight average molecular weight of the polymethylsilane is 700-1000, the impregnation temperature is 20-50 ℃, the impregnation pressure is 0.2-0.8 MPa, the impregnation time is 10-20 min, the curing temperature is 100-130 ℃, the curing pressure is 1-3 MPa, the curing time is 0.5-2 h, the protective atmosphere during cracking is nitrogen or argon, the cracking temperature is 1000-1300 ℃, the cracking pressure is 1-3 MPa, and the cracking time is 2-6 h.

In the above preparation method of the ceramic matrix composite, preferably, in the step (6), the vacuum degree of the gas-phase siliconizing is 1Pa to 300Pa, the temperature of the gas-phase siliconizing is 1500 ℃ to 1650 ℃, and the time of the gas-phase siliconizing is 0.5h to 2 h.

In the preparation method of the ceramic matrix composite material, preferably, in the step (4), the nano TiO-containing material is₂The preparation steps of the asphalt comprise: preparing asphalt, heating to 160-180 ℃, stirring for 2-3 h, and adding nano TiO 20-40% of asphalt mass₂Continuously stirring the powder for 1 to 2 hours, and then adding PEG10000 solid powder, wherein the mass of the PEG10000 solid powder is asphalt and nano TiO₂1 to 2 percent of the total mass, continuously stirring for 1 to 2 hours, and then leading the nano TiO to be vibrated by ultrasound₂More uniformly dispersed in the asphalt to obtain the product containing nano TiO₂The asphalt of (1).

In the preparation method of the ceramic matrix composite material, preferably, in the step (3), the repetition time is 1 to 10 times; in the step (4), the repetition frequency is 1 to 8 times.

As a general technical concept, the invention also provides application of the ceramic matrix composite material or the ceramic matrix composite material prepared by the preparation method in the field of braking or aerospace structural parts.

In the invention, the CVD-C is chemical vapor deposition C, the CVD-SiC is chemical vapor deposition SiC, the PIP-SiC is precursor impregnation solidification cracking SiC, and the GSI-SiC is gas phase siliconizing sintering SiC.

In the invention, the required density is not limited, and can be designed according to actual needs and obtained according to the mass fraction of each component.

Compared with the prior art, the invention has the advantages that:

1. the carbon ceramic material of the invention firstly deposits a CVD-C compact layer on the surface of carbon fiber, the interface between the CVD-C and the carbon fiber is well combined, then a CVD-SiC compact layer is added outside the CVD-C layer to strengthen the protection of the carbon fiber, then a PIP-SiC layer is produced by dipping and cracking outside the two compact layers, and then asphalt carbon is introduced into the rest pores of the material, in the later GSI process, after silicon permeates into a porous body, most of the silicon reacts with the asphalt carbon to produce GSI-SiC, and along with the completion of the reaction of the carbon and the silicon, the newly produced GSI-SiC layer and the PIP-SiC layer form relatively compact SiC and are connected with the CVD-SiC into a whole, thus on one hand, the thickness of a protective layer outside the carbon fiber is effectively increased, on the other hand, the newly produced GSI-SiC occupies most of the original pores of the material to reduce the subsequent silicon permeating channels, these two factors make it more difficult for residual Si to react with carbon fibers through the protective layer, thereby reducing the extent of silicidation damage to the carbon fibers.

The invention contains nano TiO₂The asphalt is in the carbonization process, gas generated by reaction can promote the asphalt to generate porous carbon in the carbonization process, the porosity, the pore surface area and the microstructure of the pyrolytic asphalt carbon are changed, the reaction activity of matrix carbon is improved, carbon-silicon reaction in the subsequent gas-phase siliconizing process is more thorough, the space distribution is more uniform, the defects that in the traditional asphalt carbon and silicon reaction process, large asphalt carbon has a sandwich and large-area residual silicon, the surface and the internal silicon infiltration amount of the composite material are not uniform, and the inner and outer components of the composite material are not uniform are avoided. The method for generating porous carbon after carbonizing asphalt can ensure that the subsequent introduction of carbon and silicon reaction is complete, and is convenient for theoretical calculation of silicon demand in the silicon-carbon reaction process, so that the ceramic matrix composite material with low residual Si can be designed and realized, and the ceramic in the material is increasedThe proportion of the components improves the material performance.

The invention is prepared by impregnating C/C-SiC intermediate containing nano TiO₂The pitch is carbonized to enable TiO to be formed₂Pre-uniformly dispersed in the asphalt and then TiO₂TiC particles are generated after the reaction with asphalt carbon, the TiC is dispersed in the material, and the PIP-SiC, the GSI-SiC and the TiC are not obviously layered or concentrated, so that the problems that the TiC is concentrated and the crystal grains are larger when liquid Ti metal reacts with the carbon matrix in the traditional alloy infiltration process are solved. According to the invention, the TiC phase of the transition metal carbide is introduced into the carbon-ceramic brake material and is dispersed in the SiC phase, so that the ablation resistance and the oxidation resistance of the material can be improved, and the problems that the friction component of the traditional ceramic matrix composite material is only a SiC matrix, the fluctuation of a moment curve in the braking process is large and the friction coefficient is large in discreteness can be solved.

In the prior art, SiC prepared by a PIP method is in a micro block shape in a carbon ceramic material, and the SiC is not chemically connected with each other, so that the PIP-SiC micro block is easy to drop in the actual use process. The invention introduces the pitch carbon between the PIP-SiC micro blocks to be connected to form a continuous SiC layer, and overcomes the defect that the PIP-SiC micro blocks are easy to fall.

2. The TiC and the SiC of various types are introduced into the ceramic matrix composite material, so that the performance defect of the material caused by introducing the SiC of single type by adopting a single process is overcome, the limitation of combination between the processes can be broken through, the good cooperation and the synergistic effect of the multiple processes are realized through multiple designs such as process sequence, process conditions and the like, the TiC is well combined with PIP-SiC and GSI-SiC and is uniformly dispersed, the temperature resistance and the oxidation resistance of the material are improved, and the material has excellent frictional wear performance, mechanical property and thermal property. In addition, by controlling the proportion of the components of the composite material or the process conditions (such as process time and the like), the content proportion of TiC and SiC of different types can be designed, the requirements of different working conditions on the material performance are met, and the comprehensive performance of the material is improved.

Detailed Description

The invention is further described below with reference to specific preferred embodiments, without thereby limiting the scope of protection of the invention. Unless otherwise specified, materials and instruments used in the following examples are commercially available.

Example 1

carbon fiber: 22.7 percent of the total weight of the steel,

CVD-C：28.8％，

CVD-SiC：13.0％，

PIP-SiC：17.8％，

GSI-SiC：7.9％，

TiC: 7.4%, and

residual Si: 2.4 percent.

A preparation method of the ceramic matrix composite material comprises the following steps:

(1) and C, deposition of a layer: adopting carbon fibers to prepare single-layer 0-degree laid cloth, 90-degree laid cloth and a tire fabric, sequentially and circularly superposing the 0-degree laid cloth, the tire fabric, the 90-degree laid cloth and the tire fabric in sequence, then adopting a needling method to sew, introducing carbon fiber bundles in the direction vertical to the layering direction, and preparing the three-dimensional needled carbon fiber preform with the density of 0.53g/cm³. Depositing and densifying the three-dimensional needled carbon fiber preform by a chemical vapor deposition method, wherein a precursor of a carbon source is propylene, a diluent gas is nitrogen, the volume flow ratio of the propylene to the nitrogen is 3: 1, the deposition temperature is 950 ℃, and densifying is carried out to obtain 1.19g/cm³And (4) obtaining the CVD-C blank.

(2) Depositing a SiC layer: depositing and introducing a SiC layer on the surface of the C/C blank by a chemical vapor deposition method, wherein trichloromethylsilane (CH) is selected₃SiCl₃Abbreviated as MTS) is used as a gas source for depositing the SiC matrix, hydrogen and argon are respectively used as a carrier gas and a diluent gas, the MTS is introduced into a reaction chamber by a bubbling method, the molar ratio of the hydrogen to the MTS is 8, the deposition temperature is 1000 ℃, CVD-SiC is obtained, a C/C-SiC intermediate I is formed, and the density of the C/C-SiC intermediate I is 1.49g/cm³。

(3) Preparing SiC by dipping and cracking a precursor: placing the C/C-SiC intermediate I with the SiC layer in a reactorDipping the mixture in a dipping solution consisting of polymethylsilane and xylene, wherein the mass ratio of the xylene to the polymethylsilane in the dipping solution is 30: 100. The weight average molecular weight of the polymethylsilane is 800, the impregnation temperature is 30 ℃, the pressure is 0.5MPa, and the impregnation time is 20 min. And curing after dipping at the curing temperature of 110 ℃, under the curing pressure of 1MPa for 2 h. And finally, carrying out high-temperature cracking under the protection of nitrogen, wherein the cracking temperature is 1050 ℃, the cracking pressure is 2MPa, and the cracking time is 4 h. The impregnation, curing and cracking were repeated 5 times to form PIP-SiC having a density of 1.88g/cm³C/C-SiC intermediate II.

(4) Impregnating pitch-carbonizing: C/C-SiC intermediate II and nano TiO are dispersed₂The asphalt is put into an impregnation furnace, vacuum pumping is started to be less than 50Pa after sealing, power is transmitted to heat up to asphalt melting after 30 minutes, vacuum pumping is stopped, nitrogen is used for pressurizing to 1.4MPa, pressure is kept, temperature is raised to 210 ℃ for impregnation, impregnation time is set to 2 hours, after natural cooling to room temperature, temperature is raised to 1000 ℃ in a carbonization furnace under the protection of inert atmosphere, and carbonization is carried out for 5 hours. The impregnation of the pitch-carbonization was repeated 4 times to obtain a density of 2.06g/cm³The C/C-SiC intermediate II of the asphalt-containing carbonized material.

(5) Preparing TiC: placing C/C-SiC intermediate II containing pitch carbonized material in a carbonization furnace, heating under the protection of flowing inert Ar gas, heating to 1500 deg.C, maintaining for 20min, and adding nanometer TiO₂And the reaction product reacts with the asphalt-based carbon in situ to be converted into TiC, and a C/C-SiC material intermediate III containing dispersed TiC is obtained.

(6) Gas-phase siliconizing: and (3) placing the C/C-SiC material intermediate III containing the dispersed TiC into a high-temperature vacuum furnace for gas phase siliconizing, wherein the vacuum degree is 100Pa, the siliconizing temperature is 1550 ℃, and the siliconizing time is 1h, so that GSI-SiC is obtained, and finally the ceramic matrix composite is prepared.

In step (4) of this example, the nano TiO is contained₂The preparation steps of the asphalt comprise: adding asphalt into a container, heating to 170 ℃, stirring for 2h, and adding nano TiO 35% of asphalt mass₂Stirring for 1 hr, grinding flake PEG10000 solid into powder, and adding into stirred asphalt and TiO₂In the mixture, PEG10000 solid powderThe mass of the asphalt is asphalt and nano TiO₂Continuously stirring for 1.5h based on 1% of the total mass, and then ultrasonically vibrating to enable the nano TiO₂More uniformly dispersed in the asphalt to obtain the product containing nano TiO₂The asphalt of (1). Nano TiO-containing materials used in other examples₂The asphalt can be prepared by the method.

In step (3) of this example, the polymethylsilane comprises the following preparation process: toluene is taken as a reaction solvent, toluene and a metal sodium block are added into a three-neck flask, the mixture is heated until the sodium block is molten, stirred at a high speed and smashed into sodium sand, a methyl dichlorosilane monomer is dropwise added, the heating is stopped after the mixture is refluxed for 24 hours at 80 ℃, a system is kept stand and cooled, after the solution is layered, the solution is filtered by a stainless steel capillary tube with one end wrapped by filter paper under the protection of nitrogen, the obtained filtrate is subjected to reduced pressure distillation to remove the toluene, and the obtained light yellow viscous oily liquid is the polymethylsilane. The polymethylsilanes used in other examples can be prepared by this method, but are not limited thereto.

The ceramic matrix composite prepared by the method of this example 1 was used as a sample, and the mechanical properties, thermal properties and frictional wear of the sample were measured, and the results are shown in table 1. Compared with other embodiments, the composite material prepared by the embodiment has better mechanical property and frictional wear property and better comprehensive performance, can be applied to the field of high-performance friction braking, and can also be used for manufacturing aerospace structural members.

Table 1 results of performance testing of sample materials of example 1

Example 2

carbon fiber: 22.5 percent of the total weight of the steel,

CVD-C：27.4％，

CVD-SiC：19.1％，

PIP-SiC：10.4％，

GSI-SiC：8.9％，

TiC: 9.2%, and

residual Si: 2.5 percent.

(1) and C, deposition of a layer: adopting carbon fibers to prepare single-layer 0-degree laid cloth, 90-degree laid cloth and a tire fabric, sequentially and circularly superposing the 0-degree laid cloth, the tire fabric, the 90-degree laid cloth and the tire fabric in sequence, then adopting a needling method to sew, introducing carbon fiber bundles in the direction vertical to the layering direction, and preparing the three-dimensional needled carbon fiber preform with the weight of 0.53g/cm³. Depositing and densifying the three-dimensional needled carbon fiber preform by a chemical vapor deposition method, wherein a precursor of a carbon source is propylene, a diluent gas is nitrogen, the volume flow ratio of the propylene to the nitrogen is 3: 1, the deposition temperature is 1000 ℃, and densifying is carried out to obtain 1.17g/cm³To obtain CVD-C.

(2) Depositing a SiC layer: depositing and introducing a SiC layer on the surface of the C/C blank by a chemical vapor deposition method, wherein the deposition process is the same as that of the example 1 to obtain CVD-SiC, and a C/C-SiC intermediate I is formed, and the density of the C/C-SiC intermediate I is 1.61g/cm³。

(3) Preparing SiC by dipping and cracking a precursor: and (3) soaking the C/C-SiC intermediate I in a soaking solution consisting of polymethylsilane and xylene, wherein the mass ratio of the xylene to the polymethylsilane in the soaking solution is 40: 100, the weight-average molecular weight of the polymethylsilane is 800, the soaking temperature is 40 ℃, the pressure is 0.6MPa, and the soaking time is 20 min. And curing after dipping at the curing temperature of 120 ℃, under the curing pressure of 2MPa for 1.5 h. And finally, carrying out pyrolysis under the protection of nitrogen, wherein the pyrolysis temperature is 1100 ℃, the pyrolysis pressure is 2MPa, and the pyrolysis time is 3 h. The impregnation, curing and cracking were repeated 3 times to form PIP-SiC having a density of 1.86g/cm³C/C-SiC intermediate II.

(4) Impregnating pitch-carbonizing: C/C-SiC intermediate II and nano TiO are dispersed₂The asphalt is put into an impregnation furnace, vacuum pumping is started to be less than 100Pa after sealing, vacuum pumping is stopped after 30 minutes, the asphalt is heated to be molten by power transmission, the pressure is increased to 1.4MPa by nitrogen, the pressure is maintained, and the temperature is increased toSoaking at 220 deg.C for 2h, naturally cooling to room temperature, heating to 1100 deg.C in a carbonization furnace under protection of inert atmosphere, and carbonizing for 4 h. The impregnation of the pitch-carbonization was repeated 3 times to obtain a density of 2.11g/cm³The C/C-SiC intermediate II of the asphalt-containing carbonized material.

(5) Preparing TiC: placing the C/C-SiC intermediate II body containing the asphalt carbonized material in a carbonization furnace in a flowing atmosphere N₂Heating in air to 1500 deg.C, maintaining the temperature for 20min, and adding nanometer TiO₂And the reaction product reacts with the asphalt-based carbon in situ to be converted into TiC, and a C/C-SiC material intermediate III containing dispersed TiC is obtained.

(6) Gas-phase siliconizing: placing the C/C-SiC material intermediate III containing dispersed TiC in a high-temperature vacuum furnace for gas-phase siliconizing at the vacuum degree of 50Pa, the siliconizing temperature of 1600 ℃ and the siliconizing time of 1h to obtain GSI-SiC, and finally preparing to obtain the C/C-SiC material intermediate III with the density of 2.34g/cm³The ceramic matrix composite of (1).

The ceramic matrix composite prepared by the method of this example 2 was used as a sample, and the mechanical properties, thermal properties and frictional wear of the material were measured, and the results are shown in table 2. Compared with other embodiments, the mass fraction of the ceramic matrix composite CVD-SiC of the embodiment is relatively highest, the thermal conductivity and the coefficient of friction stability of the ceramic matrix composite are relatively highest, and the wear rate is relatively lowest, so that the ceramic matrix composite CVD-SiC is more suitable for being applied to the field of high-performance friction braking.

Table 2 results of performance testing of sample materials of example 2

Example 3

The carbon ceramic material comprises the following components in percentage by mass:

carbon fiber: 22.5 percent of the total weight of the steel,

CVD-C：24.0％，

CVD-SiC：10.1％，

PIP-SiC：24.8％，

GSI-SiC：7.8％，

TiC: 8.3%, and

residual Si: 2.5 percent.

(1) and C, deposition of a layer: adopting carbon fibers to prepare single-layer 0-degree laid cloth, 90-degree laid cloth and a tire fabric, sequentially and circularly superposing the 0-degree laid cloth, the tire fabric, the 90-degree laid cloth and the tire fabric in sequence, then adopting a needling method to sew, introducing carbon fiber bundles in the direction vertical to the layering direction, and preparing the three-dimensional needled carbon fiber preform with the weight of 0.53g/cm³. Depositing and densifying the three-dimensional needled carbon fiber preform by a chemical vapor deposition method, wherein a precursor of a carbon source is propylene, a diluent gas is nitrogen, the volume flow ratio of the propylene to the nitrogen is 3: 1, the deposition temperature is 1000 ℃, and densifying is carried out to obtain 1.08g/cm³To obtain CVD-C.

(2) Depositing a SiC layer: depositing and introducing a SiC layer on the surface of the C/C blank by a chemical vapor deposition method, and obtaining CVD-SiC by the same deposition process as the example 1 to form a C/C-SiC intermediate I, wherein the density of the C/C-SiC intermediate I is 1.32g/cm³。

(3) Preparing SiC by dipping and cracking a precursor: and (3) soaking the C/C-SiC intermediate I in a soaking solution consisting of polymethylsilane and xylene, wherein the mass ratio of the xylene to the polymethylsilane in the soaking solution is 35: 100, the weight-average molecular weight of the polymethylsilane is 800, the soaking temperature is 40 ℃, the pressure is 0.6MPa, and the soaking time is 20 min. And curing after dipping at the curing temperature of 120 ℃, under the curing pressure of 2MPa for 2 h. And finally, carrying out pyrolysis under the protection of argon, wherein the pyrolysis temperature is 1200 ℃, the pyrolysis pressure is 2MPa, and the pyrolysis time is 3 h. The impregnation, curing and cracking were repeated 6 times to give a density of 1.91g/cm³The intermediate II of C/C-SiC is also obtained, namely PIP-SiC is obtained.

(4) Impregnating pitch-carbonizing: C/C-SiC intermediate II and nano TiO are dispersed₂The asphalt is put into an impregnation furnace, vacuum pumping is started to 100Pa after sealing, after 30 minutes, power is transmitted and temperature is raised until the asphalt is melted, vacuum pumping is stopped, nitrogen is used for pressurizing to 1.4MPa, pressure is maintained and temperature is raised to 210 ℃ for impregnation, the impregnation time is set to be 2 hours, and natural cooling is carried outCooling to room temperature, putting in a carbonization furnace, heating to 1100 ℃ under the protection of inert atmosphere, and carbonizing for 4 h. The impregnation of the pitch-carbonization was repeated 4 times to obtain a density of 2.19g/cm³The C/C-SiC intermediate II of the asphalt-containing carbonized material.

(5) Preparing TiC: in a carbonization furnace, the C/C-SiC intermediate II body containing the asphalt carbonized material is placed in the carbonization furnace to flow N₂Heating in air to 1550 deg.C, and maintaining the temperature for 20min₂And the reaction product reacts with the asphalt-based carbon in situ to be converted into TiC, and a C/C-SiC material intermediate III containing dispersed TiC is obtained.

(6) Gas-phase siliconizing: placing the C/C-SiC material intermediate III containing dispersed TiC in a high-temperature vacuum furnace for gas-phase siliconizing at the vacuum degree of 80Pa, the siliconizing temperature of 1600 ℃ and the siliconizing time of 1h to obtain GSI-SiC, and finally preparing to obtain the C/C-SiC material intermediate III with the density of 2.33g/cm³The ceramic matrix composite of (1).

The C/C-SiC composite material prepared by the method of this example 3 was used as a sample, and the mechanical properties and thermal properties of the material were measured on the sample, and the results are listed in table 3. Compared with other embodiments, the composite material prepared by the embodiment has excellent bending strength, and is more suitable for being used as an aerospace structural member.

Table 3 results of performance testing of sample materials of example 3

Comparative example

A C/C-SiC composite material comprises the following components in percentage by mass:

carbon fiber: 26.5 percent of the total weight of the steel,

CVD-C：34.2％，

GSI-SiC: 30.2%, and

residual Si: 9.1 percent.

The preparation method comprises the following steps:

(1) adopting carbon fiber to prepare single-layer 0-degree laid cloth, 90-degree laid cloth and tire fabric, sequentially and circularly superposing the 0-degree laid cloth, the tire fabric, the 90-degree laid cloth and the tire fabric in sequence, and then adopting needling to laminateThe method comprises the steps of sewing, introducing carbon fiber bundles in the direction vertical to the layering direction, and obtaining the carbon fiber bundles with the density of 0.56g/cm³The three-dimensional needled carbon fiber preform of (1). Depositing and densifying the three-dimensional needled carbon fiber preform by a chemical vapor deposition method, wherein a precursor of a carbon source is propylene, a diluent gas is nitrogen, the volume flow ratio of the propylene to the nitrogen is 3: 1, the deposition temperature is 950 ℃, and the densified carbon fiber preform is 1.52g/cm³C/C green body of (2).

(2) The density of the mixture is 1.52g/cm³The C/C blank body is subjected to gas phase siliconizing, the siliconizing vacuum degree is 100Pa, the temperature is 1600 ℃, the time is 3 hours, and the prepared density is 2.18g/cm³The C/C-SiC composite material of (1).

The C/C-SiC composite material prepared by the method of the comparative example was used as a sample, and the mechanical properties, thermal properties and frictional wear of the material were measured, and the results are shown in Table 4.

Table 4 results of performance testing of comparative example sample materials

Through the material performance test results of comparative examples and comparative samples, the ceramic matrix composite prepared by the invention has the characteristics of low density, high strength, high fracture toughness, good thermal conductivity, proper dynamic friction coefficient, low wear rate, good friction coefficient stability and the like.

The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make many possible variations and modifications to the disclosed embodiments, or equivalent modifications, without departing from the spirit and scope of the invention, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention.

Claims

1. A preparation method of a ceramic matrix composite material comprises the following steps:

(6) gas-phase siliconizing: carrying out gas-phase siliconizing on the obtained C/C-SiC material intermediate III containing the dispersed TiC under the vacuum condition to obtain GSI-SiC, and finally forming a C/C-SiC composite material containing the TiC and three types of SiC, namely a ceramic matrix composite material;

the ceramic matrix composite comprises the following components in percentage by mass:

20 to 30 percent of carbon fiber,

CVD-C 20%～40%，

CVD-SiC 10%～25%，

PIP-SiC 5%～25%，

GSI-SiC 5%～15%，

TiC 5% -15%, and

the residual Si is less than 3%.

2. The method for preparing ceramic matrix composite according to claim 1, wherein in step (5), the protective atmosphere is nitrogen or argon, the heating temperature is 1450 ℃ to 1550 ℃, and the heating time is 15min to 30 min.

3. The method for preparing ceramic matrix composite material according to claim 1, wherein in step (4), the vacuum-pressure impregnation process comprises: vacuumizing to less than 500Pa under a sealed condition, heating to melt asphalt after 20-40 min, stopping vacuumizing, pressurizing to 1.0-1.6 MPa by using protective gas, wherein the temperature of pressurizing and impregnating the asphalt is 200-220 ℃, and the time of pressurizing and impregnating the asphalt is 1-3 h; the carbonization temperature is 900-1200 ℃, and the carbonization time is 4-6 h.

4. The method for preparing the ceramic matrix composite according to any one of claims 1 to 3, wherein in the step (3), the mass ratio of xylene to polymethylsilane in the impregnation solution is 20-40: 100, the weight average molecular weight of the polymethylsilane is 700-1000, the impregnation temperature is 20-50 ℃, the impregnation pressure is 0.2-0.8 MPa, the impregnation time is 10-20 min, the curing temperature is 100-130 ℃, the curing pressure is 1-3 MPa, the curing time is 0.5-2 h, the protective atmosphere during cracking is nitrogen or argon, the cracking temperature is 1000-1300 ℃, the cracking pressure is 1-3 MPa, and the cracking time is 2-6 h.

5. The preparation method of the ceramic matrix composite according to any one of claims 1 to 3, wherein in the step (6), the vacuum degree of the gas-phase siliconizing is 1Pa to 300Pa, the temperature of the gas-phase siliconizing is 1500 ℃ to 1650 ℃, and the time of the gas-phase siliconizing is 0.5h to 2 h.

6. The preparation method of ceramic matrix composite according to any one of claims 1 to 3, wherein in step (4), the nano TiO-containing material₂The preparation steps of the asphalt comprise: preparing asphalt, heating to 160-180 ℃, stirring for 2-3 h, and adding nano TiO 20-40% of asphalt mass₂Continuously stirring the powder for 1 to 2 hours, and then adding PEG10000 solid powder, wherein the mass of the PEG10000 solid powder is asphalt and nano TiO₂1 to 2 percent of the total mass, continuously stirring for 1 to 2 hours, and then leading the nano TiO to be vibrated by ultrasound₂More uniformly dispersed in the asphalt to obtain the product containing nano TiO₂The asphalt of (1).

7. The method for preparing a ceramic matrix composite according to any one of claims 1 to 3, wherein in the step (3), the number of repetitions is 1 to 10; in the step (4), the repetition frequency is 1 to 8 times.

8. A ceramic matrix composite material prepared according to the preparation method of any one of claims 1 to 7.

9. The ceramic matrix composite according to claim 8, wherein the ceramic matrix composite has a density of 2.1g/cm³～2.5g/cm³The bending strength of the ceramic matrix composite material is not less than 350MPa, and the fracture toughness is not less than 10 MPa-m^1/2The thermal conductivity of the ceramic matrix composite is more than or equal to 50 W.m^-1·K^-1The dynamic friction coefficient of the ceramic matrix composite material is 0.3-0.5, and the wear rate is less than or equal to 0.3 mu m/timeThe coefficient of friction stability is more than or equal to 0.85.

10. Use of a ceramic matrix composite according to claim 8 or 9 in the field of braking or aerospace structural elements.