Nano TiC modified and reinforced C / C-SiC composite brake material and preparation method thereof

Abstract

The invention relates to the field of C / C-SiC composite materials, and discloses a reinforcement which is sequentially provided with a pyrolytic carbon interface layer, a TiC-carbon composite interface layer and a SiC layer from inside to outside. Wherein the TiC-carbon composite interface layer comprises nano TiC particles and resin carbon, the nano TiC particles are arranged in the pyrolytic carbon interface layer and the SiC layer in a pinning manner, and the resin carbon provides a carbon source for the SiC layer. A reaction carbon source is provided for the SiC layer through the TiC-carbon composite interface layer, the PyC interface strength is reserved, meanwhile, through pinning of nano TiC particles at the interface, crack propagation is controlled, the composite material interface connection strength is improved, TiC and silicon can generate an anti-oxidation barrier composed of Ti5Si3 and Ti3SiC2, and the stability of a material friction layer is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of C / C-SiC composite materials, and particularly relates to a nano-TiC modified and reinforced C / C-SiC composite brake material and a preparation method thereof. BACKGROUND

[0002] C / C-SiC composite materials are often applied in the fields of airplanes, automobiles and high-speed trains, and can be used as brake materials. The C / C-SiC composite materials perform well under conventional working conditions, but face severe challenges under extreme braking conditions. For example, when the train braking speed exceeds 400 km / h or heavy load impact is borne, the instantaneous high temperature generated at the friction interface can reach above 1500℃, resulting in the loss of stability of the friction interface.

[0003] The existing C / C-SiC composite materials mostly adopt a PyC / SiC interface design to improve the performance of the C / C-SiC composite materials. In the actual preparation process, Si and C elements are infiltrated in the outer PyC layer to prepare a SiC layer. When SiC is infiltrated, the PyC layer as a carbon source can react with Si to form a SiC matrix. The Si element will rob the carbon element of the PyC layer, damaging the quality of the PyC interface and even the carbon fibers, thereby reducing the strength of the composite material. Since the elements will combine with the carbon of the adjacent interface layer when infiltrated, the problem of carbon robbing is difficult to solve. At the same time, there is a serious mismatch in the modulus between the structural layer and the functional layer of the C / C-SiC composite material. Under typical high-speed repeated braking cycles, the rate of crack propagation along the interlayer can reach 10 -6 m / cycle, which will cause the material interface to delaminate and shorten the service life of the braking component by more than 40%.

[0004] It can be seen that in the C / C-SiC composite material, there is a problem of interface damage caused by the robbing of C in the PyC interface layer or other interface layers. At the same time, interface damage will further cause more serious interface mismatch. Therefore, how to further improve the interface strength of the C / C-SiC composite material, reduce the interface mismatch and improve the interface connection strength is an urgent problem to be solved. SUMMARY

[0005] The present application aims to provide a nano-TiC modified and reinforced C / C-SiC composite brake material and a preparation method thereof, so as to solve the technical problem of insufficient interface layer connection strength in the existing C / C-SiC composite material.

[0006] To solve the above technical problems, the present application specifically provides the following technical solutions:

[0007] The application provides a nano TiC modified reinforced C / C-SiC composite braking material, which comprises a reinforcing body, and the reinforcing body is sequentially provided with a pyrolytic carbon interface layer, a TiC-carbon composite interface layer and a SiC layer from inside to outside.

[0008] The TiC-carbon composite interface layer comprises nano TiC particles and resin carbon, the nano TiC particles are arranged into the pyrolytic carbon interface layer and the SiC layer, and the resin carbon provides a carbon source for the SiC layer.

[0009] As a preferred scheme of the application, the reinforcing body is composed of a three-dimensional needle-punched structure carbon fiber preform.

[0010] As a preferred scheme of the application, the three-dimensional needle-punched structure carbon fiber preform comprises a 0° non-woven fabric layer and a 90° non-woven fabric layer, and a short fiber web layer is arranged between the 0° non-woven fabric layer and the 90° non-woven fabric layer.

[0011] As a preferred scheme of the application, the nano TiC modified reinforced C / C-SiC composite braking material has a bending strength of 200-250 MPa, a Leeb hardness of 750-850, a friction coefficient of 0.35-0.42 and an abrasion rate of ≤3*10 -7 cm 3 / (N·m).

[0012] The application further provides a preparation method of the nano TiC modified reinforced C / C-SiC composite braking material.

[0013] S100, depositing pyrolytic carbon on the surface of a reinforcing body to form a pyrolytic carbon interface layer, and preparing a C / C preform;

[0014] S200, mixing TiC nano particles and a phenolic resin solution, and performing dispersion treatment to prepare stable composite slurry; injecting the composite slurry into the C / C preform to perform impregnation treatment, so that the composite slurry penetrates into the fiber network of the C / C preform to obtain an impregnated material;

[0015] S300, sequentially performing forming treatment and carbonization treatment on the impregnated material in a mold, and the TiC nano particles enter the C / C preform by being carbonized with the phenolic resin solution to prepare a C / C-TiC three-dimensional material, and the C / C-TiC three-dimensional material contains resin carbon;

[0016] S400, performing a reaction silicon infiltration treatment on the C / C-TiC three-dimensional material, so that elemental silicon and the resin carbon generate SiC, until residual pores of the C / C preform are fully filled with SiC to form a SiC layer, the TiC nanoparticles are nailed into the SiC layer with the resin carbon, and free Si in the SiC layer is removed, to obtain the nano-TiC modified reinforced C / C-SiC composite braking material.

[0017] As a preferred scheme of the present application, in the S200, the mass fraction of the TiC nanoparticles in the composite slurry is 35% of the phenolic resin solution;

[0018] The particle size of the TiC nanoparticles is 30-80 nm;

[0019] The impregnation treatment comprises the following steps:

[0020] The composite slurry is injected into the C / C preform by using a vacuum-assisted resin transfer molding process, the impregnation temperature is 60-80℃, the vacuum degree is <-0.09MPa, and the duration is ≥2 hours.

[0021] As a preferred scheme of the present application, in the S300, the forming treatment comprises the following steps:

[0022] A pressure of 3MPa is applied to the mold at 200℃, and hot-pressing curing is performed for 12 hours, so that the phenolic resin in the composite slurry is cross-linked and cured with the carbon fiber network in the C / C preform to form an integral structure, and the TiC nanoparticles are nailed into the pyrolytic carbon interfacial layer with the cross-linking of the phenolic resin.

[0023] As a preferred scheme of the present application, in the S300, the carbonization treatment comprises the following steps:

[0024] The formed impregnated material is heated to 1000℃ in an inert atmosphere at a heating rate of 3℃ / min, and the temperature is kept for 60 hours, the inert atmosphere is argon or nitrogen, so that the C / C-TiC three-dimensional material contains a carbon-based intermediate layer with TiC particle nails.

[0025] As a preferred scheme of the present application, in the S100, the deposition step of the pyrolytic carbon interfacial layer is as follows:

[0026] A chemical vapor deposition process is used, the reaction atmosphere is methane / hydrogen, the volume ratio of methane / hydrogen is 1:4, the deposition is performed at 1000℃ for 100h, until the deposition thickness of the pyrolytic carbon interfacial layer on the surface of the carbon fiber of the PAN-based carbon fiber felt reaches 3μm;

[0027] The density of the C / C preform is 1.1 g / cm 3 The porosity is 50%.

[0028] As a preferred scheme of the present application, in the S400, the reaction siliconizing treatment comprises the following steps:

[0029] The C / C-TiC three-dimensional material is placed in a mixed bed of silicon powder and carbon powder, and is kept at a temperature of 1900 DEG C for 4 hours in a protective atmosphere, which is vacuum or argon protection.

[0030] Compared with the prior art, the present application has the following beneficial effects:

[0031] In the material provided by the present application, the TiC-carbon composite interface layer is introduced into the PyC interface layer and the SiC layer, so that the carbon distribution of the pyrolytic carbon interface layer, the TiC-carbon composite interface layer and the SiC layer is more uniform, the modulus of the interface layer is more uniform, the mismatch is reduced, the TiC nanoparticles penetrate into the pyrolytic carbon interface layer and the SiC layer, the interface connection ability of the material is improved, and the interface connection strength of the composite material is improved, and at the same time, the pinning effect is used to inhibit the interface crack propagation in the carbon fiber network layer, the crack deflection ability is improved, so that the crack propagation can be better controlled after the material is applied to the brake material;

[0032] In the material provided by the present application, TiC can generate Ti5Si3 and Ti3SiC2 oxidation-resistant barriers with silicon elements, prevent the oxidation of carbon fibers, and improve the stability of the friction layer;

[0033] The preparation method provided by the present application mixes TiC with a resin base, uniformly injects the resin base into the reinforcement through a vacuum-assisted resin transfer molding process, and then forms and carbonizes, so that the resin layer is carbonized to combine with the interlayer structure of the resin carbon and the carbon fiber network, realizing the interface regulation of the material; during the subsequent infiltration treatment, the resin carbon provides a carbon source for the Si elements in the SiC layer, thereby protecting the PyC interface layer, reducing the PyC interface quality loss and the damage to the carbon fibers, and improving the strength of the composite material. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only exemplary, and for those skilled in the art, other drawings can be obtained from the provided drawings without creative labor.

[0035] Figure 1 The present application provides a structure diagram of a three-dimensional needling structure carbon fiber preform;

[0036] Figure 2 A preparation flowchart of the nano TiC modified reinforced C / C-SiC composite braking material is provided in the present application.

[0037] Figure 3 A bending deflection-load curve of the nano TiC modified reinforced C / C-SiC composite braking material is provided in the present application.

[0038] Figure 4 A friction curve of the nano TiC modified reinforced C / C-SiC composite braking material matched with bearing steel ball is provided in the present application. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0040] The present application provides a nano TiC modified reinforced C / C-SiC composite braking material, which comprises a reinforcing body, and the reinforcing body is sequentially provided with a pyrolytic carbon interface layer, a TiC-carbon composite interface layer and a SiC layer from inside to outside.

[0041] The TiC-carbon composite interface layer contains nano TiC particles and resin carbon, the nano TiC particles are arranged into the pyrolytic carbon interface layer and the SiC layer, and the resin carbon provides a carbon source for the SiC layer.

[0042] The pyrolytic carbon interface layer is also called a PyC layer or a PyC interface layer.

[0043] In the C / C-SiC composite braking material provided by the present application, the TiC nano particles can penetrate into the pyrolytic carbon interface layer and the SiC layer adjacent thereto along with the resin carbon, the resin carbon provides a carbon source for the Si element in the SiC layer, thereby protecting the PyC interface layer, reducing the damage of the PyC interface quality and even the carbon fiber, and improving the strength of the composite material.

[0044] The introduction of the resin carbon makes the carbon distribution of the pyrolytic carbon interface layer, the TiC-carbon composite interface layer and the SiC layer more uniform, thereby uniformly modulating each interface layer and reducing mismatch.

[0045] The TiC nano particles are arranged into the pyrolytic carbon interface layer and the SiC layer, control the crack propagation, improve the interface connection ability of the material, and thereby improve the interface connection strength of the composite material.

[0046] TiC can generate Ti5Si3 and Ti3SiC2 oxidation barrier with silicon element, prevent carbon fiber oxidation, and improve the stability of the material friction layer.

[0047] The TiC-carbon composite interface serves as a metal-based hybrid layer, has heat conduction performance and excellent toughness, can quickly transfer heat when the composite brake material is heated, improves the heat dissipation effect of the three-dimensional material, and the resin material is filled in the interlayer interface, can absorb and disperse the force when the interlayer material deforms, reduce the deformation amount of the structural layer and the wear resistance, realize the gradient transition of the thermal expansion coefficient, so that the material can effectively disperse the thermal-force coupling stress in the braking process, thereby improving the connection strength.

[0048] Secondly, in the nano TiC modified and reinforced C / C-SiC composite brake material, during the silicon infiltration treatment, the SiC and a small amount of fixed TiC nanoparticles form an oxidation barrier composed of Ti5Si3 and Ti3SiC2, the oxidation barrier can increase the oxidation starting temperature of the material to 1100 DEG C, and improve the stability of the friction layer.

[0049] Compared with the existing C / C-ZrC-SiC gradient material, the innovation of the present application lies in that: not only the high toughness of the metal material in the multi-layer material is used to solve the thermal stress problem of the material in the static state, but also the dynamic friction stability of the material is improved through the interlayer control of the material; not only the bending strength of the material is improved, but also the shear delamination performance is significantly improved; not only the physical gradient design is relied on, but also the chemical coupling mechanism of TiC-SiC is used to comprehensively improve the performance of the material.

[0050] These characteristics make the present application suitable for extreme friction working conditions such as super-speed braking and heavy-load machinery.

[0051] The reinforcing body is composed of a three-dimensional needled structure carbon fiber preform, and the TiC-carbon composite interface layer is embedded in the interface layer of the three-dimensional needled structure carbon fiber preform. The three-dimensional needled structure carbon fiber preform is most widely used, which is obtained by sequentially and cyclically stacking single-layer 0° non-woven fabric, short fiber web layer, 90° non-woven fabric and carbon fiber web layer to a certain thickness, and then integrating them by relay needling. The material uses pinning effect to inhibit the interface crack propagation in the carbon fiber network layer and improves the crack deflection ability.

[0052] In the disclosed embodiment, the nano TiC modified and reinforced C / C-SiC composite brake material has a bending strength of 200-250 MPa, a Leeb hardness of 750-850, a friction coefficient of 0.35-0.42, and a wear rate of ≤3*10 -7 cm 3 / (N·m).

[0053] To solve this problem, the application further provides a method for modifying and reinforcing a C / C-SiC composite brake material by using nano TiC, comprising the following steps: Figure 2

[0054] S100, depositing pyrolytic carbon on the surface of the reinforcing body to form a pyrolytic carbon interface layer and prepare a C / C preform;

[0055] S200, mixing TiC nanoparticles with a phenolic resin solution and performing dispersion treatment to prepare a stable composite slurry; injecting the composite slurry into the C / C preform and performing impregnation treatment so that the composite slurry penetrates into the fiber network of the C / C preform to obtain an impregnated material;

[0056] S300, placing the impregnated material into a mold and sequentially performing molding treatment and carbonization treatment, so that the TiC nanoparticles are driven into the C / C preform along with the carbonization of the phenolic resin solution to prepare a C / C-TiC three-dimensional material, and the C / C-TiC three-dimensional material contains resin carbon;

[0057] S400, performing reaction silicon infiltration treatment on the C / C-TiC three-dimensional material, so that silicon and the resin carbon generate SiC, until the residual pores of the C / C preform are fully filled with SiC to form a SiC layer, the TiC nanoparticles are driven into the SiC layer along with the resin carbon, and free Si in the SiC layer is removed to prepare a nano TiC modified and reinforced C / C-SiC composite brake material.

[0058] As shown in Figure 1 The three-dimensional needled structure carbon fiber preform can be considered as being composed of a layer of non-dimensional cloth 0° or 90° and a layer of net tire alternately in the macrostructure.

[0059] The components in the three-dimensional needled structure carbon fiber preform are basically uniformly distributed, Si is a soft phase in the composite material, pyrolytic carbon is a hard phase, and graphite carbon is a soft phase. After the post-heat treatment, it can be assumed that the pyrolytic carbon basically realizes graphitization.

[0060] CVI+RMI can produce a large amount of free Si, and the infiltration reaction can damage the interface. The post-heat treatment can effectively remove the residual Si, but it increases the porosity and reduces the strength of the composite material.

[0061] To solve this problem, the application mixes TiC nanoparticles with a phenolic resin solution and performs dispersion treatment to prepare a stable composite slurry; injects the composite slurry into the C / C preform and performs impregnation treatment so that the composite material penetrates into the fiber network of the C / C preform to obtain an impregnated material, and improves the homogeneity of the resin layer. Since the composite slurry has good fluidity, the phenolic resin can also move the TiC nanoparticles. ​

[0062] The impregnated material is sequentially subjected to a molding process and a carbonization process, the phenolic resin is carbonized, the TiC nanoparticles are fixed in the carbon fiber network, the TiC nanoparticles can enter the pyrolytic carbon interface layer and the SiC layer adjacent thereto along with the resin carbon, thereby strengthening the connection effect of the interface, improving the interlayer thermal conductivity and force transmission performance, fully utilizing the interface regulation effect of the TiC nanoparticles, and realizing the dual effects of thermal stress relief and structure enhancement.

[0063] Further, the resin carbon provides a carbon source for the Si element in the SiC layer, thereby protecting the PyC interface layer, reducing PyC interface quality and even carbon fiber damage, and improving the strength of the composite material. Meanwhile, the introduction of the resin carbon makes the carbon distribution of the pyrolytic carbon interface layer, the TiC-carbon composite interface layer and the SiC layer more uniform, thereby uniformly modulating each interface layer and reducing mismatch, thereby further reducing

[0064] In the preparation method provided by the application, on the one hand, the resin carbon is introduced to provide a reaction carbon source, thereby reducing the damage of the interface by infiltration; on the other hand, the TiC nanoparticles are pinned at the interface, and the strength of the composite material is improved by changing the crack propagation mechanism.

[0065] Meanwhile, since the TiC nanoparticles are fixed in the resin material, TiC and Si element contact to form Ti5Si3 and Ti3SiC2 oxidation barriers, prevent the oxidation of carbon fibers, and improve the stability of the friction layer of the material.

[0066] In order to improve the homogeneity of the distribution of TiC nanoparticles between the layers, in S200, the mass fraction of TiC nanoparticles in the composite slurry is 35% of the phenolic resin solution. The particle size of the TiC nanoparticles is 30-80 nm.

[0067] The impregnation treatment can be selected within any range, in order to improve the homogeneity of the distribution of TiC nanoparticles between the layers, the impregnation treatment comprises the following steps:

[0068] The composite slurry is injected into the C / C preform by using a vacuum-assisted resin transfer molding process, the impregnation temperature is 60-80℃, the vacuum degree is <-0.09MPa, and the duration is ≥2 hours, so that the composite material of the composite slurry penetrates the carbon fiber network layer and the pyrolytic carbon interface layer in a needling form.

[0069] The hot pressing and curing can be selected within any range, in order to improve the homogeneity of the distribution of TiC nanoparticles between the layers, in S300, the molding process comprises the following steps:

[0070] Applying a pressure of 3MPa to the mold at 200℃ and hot-pressing for 12 hours allows the phenolic resin in the composite slurry to cross-link and solidify with the carbon fiber network in the C / C preform, forming an integral structure. TiC nanoparticles enter the pyrolytic carbon interface layer along with the cross-linking anchors of the phenolic resin.

[0071] The introduction of resin carbon and cross-linking and curing with the carbon fiber network in the C / C preform improves the structural continuity of the composite material, reduces the risk of delamination, and increases the strength of the material.

[0072] In S300, the carbonization process includes the following steps:

[0073] The molded impregnated material is heated to 1000℃ in an inert atmosphere at a heating rate of 3℃ / min and held for 60 hours. The inert atmosphere is argon or nitrogen, so that the C / C-TiC three-dimensional material contains a carbon-based intermediate layer with TiC particles anchored into it.

[0074] In S100, the deposition steps of the pyrolytic carbon interface layer are as follows:

[0075] Chemical vapor deposition was used with a reaction atmosphere of methane / hydrogen at a volume ratio of 1:4. Deposition was carried out at 1000℃ for 100 hours until the pyrolytic carbon interface layer reached a thickness of 3μm on the carbon fiber surface of the PAN-based carbon fiber felt.

[0076] The density of the C / C preform is 1.1 g / cm³. 3 The porosity is 50%.

[0077] In S400, reactive silicon diffusion treatment includes the following steps:

[0078] The C / C-TiC three-dimensional material was placed in a mixed bed of silicon powder and carbon powder and kept at 1900℃ for 4 hours under a protective atmosphere, which was either vacuum or argon.

[0079] Example 1 below verifies the performance and structure of nano-TiC modified and reinforced C / C-SiC composite braking material:

[0080] Example 1:

[0081] 1. Preparation of preforms and construction of interface layers

[0082] PAN-based T3005K three-dimensional needle-punched integral carbon felt was selected as the reinforcement, and a pyrolytic carbon (PyC) interface layer with a thickness of about 3μm was deposited on the carbon fiber surface using chemical vapor deposition (CVI) process.

[0083] The CVI conditions were: temperature 1000℃, reaction atmosphere: methane / hydrogen (volume ratio 1:4), deposition time approximately 100 h, and the density of the resulting C / C preform was approximately 1.1 g / cm³. 3 The porosity is approximately 50%.

[0084] 2. TiC nanoparticle dispersion and resin impregnation treatment

[0085] TiC nanoparticles (approximately 30-80 nm in diameter) with a mass fraction of 35% were uniformly mixed into a phenolic resin solution using ultrasonic dispersion and mechanical stirring techniques to obtain a stable composite slurry.

[0086] Vacuum-assisted resin transfer molding (RTM) is used to inject slurry into the C / C preform. The impregnation temperature is controlled at 60-80℃, the vacuum degree is better than -0.09MPa, and the duration is not less than 2 hours to ensure that the composite material is fully penetrated into the fiber network.

[0087] 3. Hot pressing curing and carbonization treatment

[0088] The impregnated material is placed in a mold and hot-pressed at 200°C with a pressure of 3 MPa for 12 hours to allow the resin to cross-link and solidify into an integral structure. Subsequently, carbonization is performed at 1000°C with a heating rate controlled at 3°C / min and held for 60 hours in an inert atmosphere of argon or nitrogen to obtain a carbon-based intermediate layer in which TiC particles are embedded.

[0089] 4. RMI reactive silicating and densification treatment

[0090] The carbonized sample was placed in a mixed bed of silicon powder and carbon powder and subjected to reactive silicon infiltration treatment at 1900℃ for 4 hours under vacuum or argon protection. This process allowed the residual pores to be fully filled by SiC ceramics and completed the graphitization process to remove free Si. Finally, a TiC-modified C / C-SiC composite material with high density and stable interfacial structure was obtained.

[0091] For Example 1, bending deflection-load and friction performance tests were performed. The bending test followed GB / T40398.2-2021 standard, with a sample size of 60×8×5mm³ and a span of 50mm. The loading speed was set to 0.5mm / min. The friction test used paired 10mm diameter Si3N4 ceramic spheres at a frequency of 5Hz, a load of 10N, and a running time of 30min.

[0092] See results Figure 3 and Figure 4 As shown in the results, the density of the material obtained in Example 1 is approximately 2.0 g / cm³. 3The porosity is less than 5%, the residual free Si content is less than 5%, and the SiC volume fraction is 45-50%. Its comprehensive performance is significantly improved: flexural strength 200-250 MPa, Leeb hardness 750-850, friction coefficient stable between 0.35-0.42, and wear rate less than 3×10⁻⁶. -7 cm 3 / (N·m).

[0093] As can be seen, the present invention achieves the separation of PyC layer and SiC layer through the above preparation method, provides reactive carbon source for SiC layer through TiC-carbon composite interface layer, retains PyC interface strength, controls crack propagation through nano-TiC particle pinning at interface, improves composite interface connection strength, and TiC can form Ti5Si3 and Ti3SiC2 antioxidant barriers with silicon element to prevent carbon fiber oxidation and improve the stability of material friction layer.

[0094] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A nano-TiC modified and reinforced C / C-SiC composite braking material, characterized in that, The reinforcement includes a pyrolytic carbon interface layer, a TiC-carbon composite interface layer, and a SiC layer, which are sequentially disposed from the inside to the outside. The TiC-carbon composite interface layer comprises nano-TiC particles and resin carbon. The nano-TiC particles are pinned to the pyrolytic carbon interface layer and the SiC layer, and the resin carbon provides a carbon source for the SiC layer.

2. The nano-TiC modified and reinforced C / C-SiC composite braking material according to claim 1, characterized in that, The reinforcement is composed of a three-dimensional needle-punched carbon fiber preform.

3. The nano-TiC modified and reinforced C / C-SiC composite braking material according to claim 2, characterized in that, The three-dimensional needle-punched carbon fiber preform includes a 0° nonwoven fabric layer and a 90° nonwoven fabric layer, with a short fiber web layer disposed between the 0° nonwoven fabric layer and the 90° nonwoven fabric layer.

4. The nano-TiC modified and reinforced C / C-SiC composite braking material according to claim 3, characterized in that, The nano-TiC modified reinforced C / C-SiC composite braking material has a flexural strength of 200-250 MPa, a Leeb hardness of 750-850, a coefficient of friction of 0.35-0.42, and a wear rate ≤3×10⁻⁶. -7 cm 3 / (N·m).

5. A method for preparing the nano-TiC modified and reinforced C / C-SiC composite braking material according to any one of claims 1-4, characterized in that, Includes the following steps: S100. Pyrolytic carbon is deposited on the surface of the reinforcement to form a pyrolytic carbon interface layer, thus obtaining a C / C preform. S200. TiC nanoparticles are mixed with phenolic resin solution and dispersed to obtain a stable composite slurry. The composite slurry is injected into the C / C preform and impregnated to allow the composite slurry to penetrate into the fiber network of the C / C preform to obtain an impregnated material. S300. The impregnating material is placed into a mold and subjected to molding and carbonization processes in sequence. The TiC nanoparticles enter the C / C preform along with the carbonization of the phenolic resin solution to obtain a C / C-TiC three-dimensional material containing resin carbon. S400. The C / C-TiC three-dimensional material is subjected to reactive silicon infiltration treatment, in which elemental silicon reacts with the resin carbon to generate SiC until the residual pores of the C / C preform are fully filled with SiC to form a SiC layer. The TiC nanoparticles enter the SiC layer along with the resin carbon pins to remove the free Si in the SiC layer, thereby obtaining the nano-TiC modified and reinforced C / C-SiC composite braking material.

6. The preparation method according to claim 5, characterized in that, In S200, the mass fraction of the TiC nanoparticles in the composite slurry is 35% of the phenolic resin solution; The TiC nanoparticles have a particle size of 30-80 nm; The impregnation process includes the following steps: The composite slurry is injected into the C / C preform using a vacuum-assisted resin transfer molding process. The impregnation temperature is 60–80°C, the vacuum degree is <-0.09 MPa, and the duration is ≥2 hours.

7. The preparation method according to claim 5, characterized in that, In S300, the molding process includes the following steps: The mold is subjected to a pressure of 3MPa at 200℃ and hot-pressed for 12 hours, which causes the phenolic resin in the composite slurry to crosslink and cure with the carbon fiber network in the C / C preform to form an integral structure. The TiC nanoparticles enter the pyrolytic carbon interface layer along with the crosslinking anchors of the phenolic resin.

8. The preparation method according to claim 5, characterized in that, In S300, the carbonization process includes the following steps: The molded impregnated material is heated to 1000°C in an inert atmosphere at a heating rate of 3°C / min and held for 60 hours. The inert atmosphere is argon or nitrogen, so that the C / C-TiC three-dimensional material contains a carbon-based intermediate layer with TiC particles anchored into it.

9. The preparation method according to claim 5, characterized in that, In step S100, the deposition step of the pyrolytic carbon interface layer is as follows: Chemical vapor deposition was used in a reaction atmosphere of methane / hydrogen with a volume ratio of 1:

4. Deposition was carried out at 1000°C for 100 hours until the pyrolytic carbon interface layer reached a deposition thickness of 3 μm on the carbon fiber surface of the PAN-based carbon fiber felt. The density of the C / C preform is 1.1 g / cm³. 3 The porosity is 50%.

10. The preparation method according to claim 5, characterized in that, In S400, the reactive silicon diffusion process includes the following steps: The C / C-TiC three-dimensional material was placed in a mixed bed of silicon powder and carbon powder and kept at 1900°C for 4 hours under a protective atmosphere, wherein the protective atmosphere was a vacuum or argon atmosphere.

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