Brake disc and preparation method, brake system, and vehicle

Abstract

A brake disc and a preparation method, a brake system, and a vehicle. The brake disc comprises a dense region and a plurality of nanoporous regions distributed at intervals in the dense region, wherein the dense region comprises a carbon fiber reinforced silicon carbide material, and the nanoporous region comprises cracked carbon in a continuous phase and carbon particles distributed in the cracked carbon, wherein the pore size of the nanoporous region ranges from 10 nm to 100 nm, and the porosity ranges from 15% to 30%.

Description

Brake disc and preparation method, brake system and vehicle

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on August 24, 2023, with application number 202311088529.9 and application name “Brake Disc and Preparation Method, Braking System and Vehicle”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of brake materials, and in particular to a brake disc and a preparation method thereof, a brake system and a vehicle. Background Art

[0003] Carbon-ceramic brake discs are gaining popularity in the market due to their superior performance. They are typically made of carbon fiber-reinforced silicon carbide / silicon, with the carbon fiber providing toughness and the silicon carbide providing wear resistance. However, the continuous phase, composed of two brittle materials, silicon carbide and free silicon, is prone to cracking when subjected to external forces. These cracks can extend to the interface between the carbon fiber and the continuous phase, resulting in longer cracks in the disc. Under long-term alternating loads, through-cracks can form in the disc, leading to disc breakage and severely shortening its service life.

[0004] Summary of the Invention

[0005] In view of this, the present application provides a brake disc, in which the nanoporous area can improve the toughness of the brake disc, thereby extending the service life of the carbon-ceramic brake disc.

[0006] In a first aspect, the present application provides a brake disc comprising a dense region and a plurality of nanoporous regions spaced apart in the dense region; wherein the dense region comprises carbon fiber-reinforced silicon carbide material, and the nanoporous region comprises cracked carbon in a continuous phase and carbon particles distributed in the cracked carbon; wherein the nanopores in the nanoporous region have a pore size range of 10 nm to 100 nm and a porosity range of 15% to 30%.

[0007] The nanoporous structure in the nanoporous area makes the nanoporous area looser at the nanoscale relative to the dense area, and the interfacial bonding force between the cracked carbon and the carbon particles is weak. When the brake disc is subjected to external force and cracks appear in the dense area, the cracks extend to the nanoporous area and along the interface of the cracked carbon / carbon particles in the nanoporous area. This extension process is also the energy absorption process of the cracks, so the cracks will gradually disappear, which can significantly improve the toughness of the brake disc and extend the service life of the brake disc.

[0008] In one embodiment, the size of the nanoporous region ranges from 30 μm to 500 μm.

[0009] In one embodiment, based on the volume of the brake disc, the sum of the volume percentages of the plurality of nanoporous regions ranges from 5% to 30%.

[0010] In one embodiment, based on the total mass of the nanoporous region, the nanoporous region comprises 30% to 70% of the carbon particles, 10% to 40% of the cracked carbon, and 0% to 50% of the silicon carbide particles.

[0011] In one embodiment, the mass percentage of the silicon carbide particles in the nanoporous region is 5% to 50%.

[0012] In one embodiment, the carbon particles have a particle size of 0.1 μm to 10 μm.

[0013] In one embodiment, the carbon particles have a D50 particle size of 0.3 μm to 10 μm.

[0014] In one embodiment, the D50 particle size of the silicon carbide particles is 0.3 μm to 20 μm.

[0015] In one embodiment, the porosity of the brake disc is in the range of 1%-5%.

[0016] A second aspect of the present application provides a method for preparing a brake disc, comprising the following steps:

[0017] (1) immersing the carbon fiber tow in a solution of a first resin, taking it out, drying, curing, and shearing it to obtain a carbon fiber reinforced resin strip;

[0018] (2) heating and pressurizing a first raw material including carbon particles and a second resin powder in a mold to solidify the first raw material, and then crushing and sieving the first raw material to obtain a granular second raw material;

[0019] (3) mixing the carbon fiber reinforced resin strip, the second raw material, the third resin powder, and the solvent, heating and stirring until the solvent evaporates to obtain a mixture; crushing and sieving the mixture, transferring it to a mold for heating and pressurizing and curing to obtain a brake disc blank; wherein the brake disc blank includes a first material distribution area and a plurality of second material distribution areas spaced apart in the first material distribution area, the first material distribution area includes the carbon fiber reinforced resin strip and the third resin powder; the second material distribution area includes the second raw material and the third resin powder;

[0020] (4) performing a carbonization treatment on the brake disc blank under a protective atmosphere, and then performing a siliconizing treatment to obtain a brake disc;

[0021] The brake disc comprises a dense region and multiple nanoporous regions spaced apart within the dense region; the dense region comprises carbon fiber-reinforced silicon carbide, and the nanoporous region comprises a continuous phase of pyrolyzed carbon and carbon particles dispersed within the pyrolyzed carbon. The nanoporous region has a pore size range of 10 nm to 100 nm and a porosity range of 15% to 30%. The preparation method is simple, reliable, and efficient, enabling large-scale industrial production.

[0022] In one embodiment, based on the total mass of the mixture, the mixture includes 20% to 50% of the carbon fiber reinforced resin strips, 20% to 40% of the second raw material, and 20% to 40% of the third resin powder.

[0023] In one embodiment, the length of the carbon fiber reinforced resin strip is 0.5 cm to 3 cm.

[0024] In one embodiment, based on the total mass of the first raw material, the first raw material includes 30% to 60% of the carbon particles, 20% to 50% of the second resin powder, and 0% to 40% of silicon carbide particles.

[0025] In one embodiment, in step (2), the sieving is performed using a sieve with a mesh size of 50 to 400.

[0026] In one embodiment, in step (3), the sieving is performed using a sieve with a mesh size of 15 to 30.

[0027] The third aspect of the present application provides a braking system comprising the brake disc provided in the first aspect of the present application. Due to the use of the carbon-ceramic brake disc provided in the first aspect of the present application, the braking system has a better braking effect, higher reliability, and longer service life.

[0028] In one embodiment, the brake system includes the carbon-ceramic brake disc, a brake caliper bracket, a brake caliper housing, and a friction plate.

[0029] The fourth aspect of the present application provides a vehicle comprising the braking system provided by the third aspect of the present application. Due to the braking system provided by the third aspect of the present application, the vehicle has good market competitiveness.

[0030] In one embodiment, the transportation vehicle includes a vehicle or an airplane; wherein the vehicle includes a car or a rail transit train. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a schematic structural diagram of any region on any cross section of a brake disc provided by an embodiment of the present application;

[0032] FIG2 is a scanning electron microscope (SEM) photograph of a cross section of the brake disc prepared in Example 2 of the present application.

[0033] Explanation of reference numerals: 1-brake disc; 10-dense area; 20-nanoporous area. DETAILED DESCRIPTION

[0034] Generally, carbon-ceramic brake discs are directly obtained from carbon fibers / carbon porous carbon through siliconization reaction. The obtained carbon-ceramic brake discs are all nano-dense structures, which are relatively brittle and lack toughness. After long-term use, through cracks are prone to appear, causing the carbon-ceramic brake disc to break, seriously affecting the service life of the carbon-ceramic brake disc. In order to solve the above technical problems, the embodiment of the present application provides a brake disc. Figure 1 is a schematic diagram of the structure of any area on any cross section of the brake disc provided by the embodiment of the present application. As shown in Figure 1, the brake disc 1 includes a dense area 10 and a plurality of nanoporous areas 20 spaced apart in the dense area 10; specifically, in some embodiments, the nanoporous area 20 is surrounded by dense areas 10;

[0035] The dense region 10 comprises carbon fiber-reinforced silicon carbide, and the nanoporous region 20 comprises a continuous phase of pyrolytic carbon and carbon particles distributed within the pyrolytic carbon. The nanoporous region 20 has a pore size ranging from 10 nm to 100 nm and a porosity ranging from 15% to 30%. Specifically, the dense region 10 comprises a continuous phase of silicon carbide and carbon fiber reinforcement distributed within the continuous phase. The pore size refers to the size of the nanopores in the nanoporous region 20.

[0036] The carbon fibers in the dense region can provide a certain degree of toughness to the brake disc. However, due to the disc's operational characteristics, the dense region requires a large amount of silicon carbide as a continuous phase. This results in the dense region being primarily brittle and lacking in toughness. The nanoporous structure dispersed within the nanoporous region makes the nanoporous region more porous at the nanoscale relative to the dense region. Furthermore, because the nanoporous region is primarily composed of cracked carbon and carbon particles, the interfacial bonding between these two materials is weak. When the brake system is activated, the friction pad in the brake system clamps the brake disc, causing friction between the disc and the friction pad to achieve braking. Repeatedly repeating this process can cause cracks to form in the dense region of the brake disc. In the brake disc provided by this application, cracks, once initiated, propagate toward the nanoporous region and along the interface between the cracked carbon and carbon particles in the nanoporous region. During this process, the crack energy is gradually absorbed by the nanoporous structure within the nanoporous region, causing the cracks formed in the dense region to gradually disappear. This significantly improves the toughness of the brake disc and extends its service life.

[0037] It should also be noted that the above-mentioned nanoporous areas and dense areas are all based on comparisons at the nanoscale. There may be holes with micron-sized pore sizes in the dense area, resulting in a visual error in the cross-sectional SEM photograph of the brake disc sample that "the dense area looks looser than the nanoporous area."

[0038] For example, the pore size of the nanoporous region can be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, etc. If the pore size of the nanoporous region is too small (less than 10 nm), the energy cannot be effectively absorbed during the crack propagation process, resulting in matrix fracture; if the pore size of the nanoporous region is too large, the crack cannot propagate, resulting in fracture of the dense region.

[0039] For example, the porosity of the nanoporous region may be 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, etc. If the porosity of the nanoporous region is too small, there will be insufficient loose areas to absorb crack energy, and the energy cannot be effectively absorbed. If the porosity of the nanoporous region is too large, the crack will not be able to propagate, thereby causing the dense region to break.

[0040] In one embodiment, the nanoporous region has a size range of 30 μm to 500 μm. It is understood that the nanoporous region is a three-dimensional structure. The size of the nanoporous region is described using a disc-shaped brake disc as an example: a disc-shaped brake disc includes an upper surface, a lower surface, and a side surface connecting the upper and lower surfaces. Cutting the brake disc along any plane will yield a nanoporous region in a cross-section with a size range of 30 μm to 500 μm. For example, the size of the nanoporous region can be 30μm, 40μm, 50μm, 60μm, 80μm, 100μm, 120μm, 150μm, 180μm, 200μm, 220μm, 250μm, 280μm, 300μm, 320μm, 350μm, 380μm, 400μm, 420μm, 450μm, 480μm, 490μm, 500μm, etc. By controlling the size of the nanoporous region within the above range, a sufficiently large loose area at the nanoscale can be provided to absorb crack energy, thereby fully improving the toughness of the brake disc, while not affecting the strength of the dense area. This can ensure the braking effect of the brake disc while fully extending the service life of the brake disc.

[0041] In one embodiment, the total volume of the brake disc is used as a reference, and the sum of the volume percentages of the multiple nanoporous regions ranges from 5% to 30%; that is, the sum of the volume percentages of all nanoporous regions in the brake disc ranges from 5% to 30%. For example, the sum of the volume percentages of the nanoporous regions can be 5%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, etc. By controlling the sum of the volume percentages of the multiple nanoporous regions in the brake disc to be within the above range, a sufficient number of nanoporous regions are spaced and dispersed within the dense region to absorb the energy generated by cracks in dense regions at different locations when subjected to external impact, making the performance of each position of the brake disc more uniform, thereby better and more comprehensively improving the toughness of the brake disc without affecting the wear resistance and strength of the brake disc.

[0042] In one embodiment, the nanoporous structure of the nanoporous region is formed by a plurality of stacked carbon particles and cracked carbon. Specifically, the plurality of carbon particles are stacked one upon the other. As will be appreciated, gaps are formed between adjacent carbon particles. The cracked carbon fills these gaps to form a continuous phase, thereby forming the nanoporous structure.

[0043] In one embodiment, the particle size of the carbon particles in the nanoporous region is 0.1 μm to 10 μm. In some specific embodiments, the D50 particle size of the carbon particles in the nanoporous region is 0.3 μm to 10 μm. Controlling the D50 particle size of the carbon particles within the above range is conducive to controlling the pore size of the nanoporous structure within a smaller range, which is more conducive to the absorption of crack energy. Exemplarily, the particle size of the carbon particles in the nanoporous region can be 0.3 μm, 0.5 μm, 1.0 μm, 2.0 μm, 3.0 μm, 4.0 μm, 5.0 μm, 6.0 μm, 7.0 μm, 8.0 μm, 9.0 μm, 10.0 μm, etc.

[0044] In one embodiment, the material of the carbon particles in the nanoporous region includes, but is not limited to, at least one of microcrystalline carbon, graphite, coke, and chopped carbon fibers. For the chopped carbon fibers, the particle size refers to the length of the chopped carbon fibers. In some specific embodiments, the length of the chopped carbon fibers is between 14 μm and 60 μm. For example, the length of the chopped carbon fibers may be 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, and the like.

[0045] In one embodiment, the nanoporous region also includes silicon carbide particles. Specifically, the nanoporous region includes carbon particles, cracked carbon, and silicon carbide particles. In some specific embodiments, the carbon particles and silicon carbide particles in the nanoporous region stack together, with the cracked carbon filling the gaps between the stacked carbon and silicon carbide particles, forming a continuous phase and ultimately forming a nanoporous structure. This allows the nanoporous region to absorb energy from cracks in the dense region, while also improving the toughness of the brake disc.

[0046] In one embodiment, the D50 particle size of the silicon carbide particles in the nanoporous region is 0.3 μm to 20 μm. Controlling the D50 particle size of the silicon carbide particles within the above range is conducive to controlling the pore size of the nanoporous structure within a smaller range, which is more conducive to the absorption of crack energy. For example, the D50 particle size of the silicon carbide particles in the nanoporous region can be 0.3 μm, 0.5 μm, 1.0 μm, 2.0 μm, 5.0 μm, 8.0 μm, 10.0 μm, 12.0 μm, 15.0 μm, 18.0 μm, 20.0 μm, etc.

[0047] In one embodiment, based on the total mass of the nanoporous region, the nanoporous region comprises 30% to 70% carbon particles, 10% to 40% pyrolysis carbon, and 0% to 50% silicon carbide particles. For example, the mass percentage of carbon particles in the nanoporous region may be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, etc.; the mass percentage of pyrolysis carbon in the nanoporous region may be 10%, 15%, 20%, 25%, 30%, 35%, 40%, etc. For example, the mass percentage of silicon carbide particles in the nanoporous region may be 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc. In some specific embodiments, the nanoporous region comprises 30% to 70% carbon particles, 10% to 40% pyrolyzed carbon, and 5% to 50% silicon carbide particles. Controlling the mass percentages of these substances within the aforementioned ranges allows for both control of the pore size and porosity of the nanoporous structure within the nanoporous region while also maintaining the strength of the nanoporous region. This improves the toughness of the brake disc while maintaining high brake strength.

[0048] In one embodiment, the length of the carbon fibers in the dense region ranges from 1 cm to 2 cm. For example, the length of the carbon fibers in the dense region can be 1.0 cm, 1.1 cm, 1.2 cm, 1.3 cm, 1.4 cm, 1.5 cm, 1.6 cm, 1.7 cm, 1.8 cm, 1.9 cm, 2.0 cm, etc. This ensures the mechanical strength of the dense region, thereby reducing the risk of cracks in the dense region, thereby improving the braking effect of the brake disc and extending its service life.

[0049] In one embodiment, the edge region of the nanoporous region comprises a continuous phase of silicon carbide.

[0050] In one embodiment, the dense region further contains free silicon. Specifically, the silicon and silicon carbide in the dense region together form a continuous phase, and carbon fibers as reinforcements are dispersed in the continuous phase.

[0051] In one embodiment, the porosity of the brake disc is in the range of 1%-5%. It is understandable that micron-sized pores may exist in the dense area. Controlling the porosity of the brake disc as a whole within the above range is conducive to the absorption of cracks in the dense area, ensuring the mechanical properties of the dense area, and thus improving the performance of the brake disc. Exemplarily, the porosity of the brake disc can be 1.00%, 1.20%, 1.40%, 1.50%, 1.60%, 1.70%, 1.80%, 1.90%, 2.00%, 2.10%, 2.20%, 2.30%, 2.40%, 2.50%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, etc.

[0052] The present invention also provides a method for preparing a brake disc, comprising the following steps:

[0053] S01, immersing the carbon fiber tow in a solution of a first resin, taking it out, drying, curing, and shearing it to obtain a carbon fiber reinforced resin strip;

[0054] S02. The first raw material comprising carbon particles and a second resin powder is heated, pressurized, and solidified in a mold, and then crushed and sieved to obtain a granular second raw material. It is understood that in the first raw material, the carbon particles are stacked on top of each other, and the second resin powder is filled in the gaps formed by the stacked carbon particles. In some embodiments of the present application, the carbon particles and the second resin powder are mixed in a solid-phase mixing device. In some specific embodiments, the carbon particles and the second resin powder are mixed in a V-type mixer.

[0055] It should be noted that the above S01 and S02 are only distinguished in terms of steps, and their order is not distinguished; in actual production, the carbon fiber reinforced resin strip can be prepared first, or the second raw material can be prepared first; or, the second raw material can be prepared first and then the carbon fiber reinforced resin strip; or, the carbon fiber reinforced resin strip and the second raw material can be prepared at the same time.

[0056] S03. Mixing the carbon fiber reinforced resin strip, the second raw material, the third resin powder, and a solvent, heating and stirring until the solvent evaporates to obtain a mixture; crushing and sieving the mixture, and then transferring it to a mold for heating and pressurizing to cure it to obtain a brake disc blank; wherein the brake disc blank includes a first material distribution area and a plurality of second material distribution areas spaced apart and dispersed in the first material distribution area, the first material distribution area including the carbon fiber reinforced resin strip and the third resin powder; and the second material distribution area including the second raw material and the third resin powder;

[0057] S04. The brake disc blank is subjected to a carbonization treatment under a protective atmosphere, and then subjected to a siliconizing treatment to obtain a brake disc; it should be noted that during the siliconizing treatment, based on the structural characteristics and raw material characteristics of the second material distribution area, it is difficult for silicon to penetrate into the second material distribution area. The carbonization treatment can convert the first resin, the second resin powder, and the third resin powder into cracked carbon; the siliconizing treatment can cause the cracked carbon in the first material distribution area to react with silicon and be converted into silicon carbide. In one embodiment, silicon may be impregnated into the raw material at the edge of the second material distribution area, resulting in the presence of silicon carbide and / or silicon at the edge of the nanoporous area in the final brake disc.

[0058] The brake disc includes a dense area and multiple nanoporous areas spaced apart in the dense area; the dense area includes carbon fiber-reinforced silicon carbide material, and the nanoporous area includes cracked carbon in a continuous phase and carbon particles dispersed in the cracked carbon; the pore size of the nanoporous area ranges from 10nm to 100nm, and the porosity ranges from 15% to 30%.

[0059] In one embodiment, the first resin, the second resin powder, and the third resin powder include but are not limited to phenolic resin. In a specific embodiment, the first resin, the second resin powder, and the third resin powder are selected from thermoplastic phenolic resin.

[0060] In one embodiment, in step S01, the solid content of the first resin solution is 40% to 60%. In some specific embodiments, the first resin solution is a phenolic resin solution with a solid content of 40% to 60%.

[0061] In one embodiment, in step S01, the carbon fiber tow impregnated with the first resin solution is dried at 50°C to 80°C, then cured at 130°C to 160°C, and then cut into carbon fiber reinforced resin strips with a length of 0.5 cm to 3 cm. Exemplarily, the drying temperature may be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, etc. Exemplarily, the curing temperature may be 130°C, 140°C, 150°C, 160°C, etc. Exemplarily, the length of the carbon fiber reinforced resin strips may be 0.5 cm, 1.0 cm, 1.5 cm, 2.0 cm, 2.5 cm, 3.0 cm, etc. Controlling the length of the carbon fiber reinforced resin strips within the above range facilitates mixing of the carbon fiber reinforced resin strips, the second raw material, and the third resin powder.

[0062] In one embodiment, in step S02, based on the total mass of the first raw material, the first raw material includes 30% to 60% of the carbon particles, 20% to 50% of the second resin powder, and 0% to 40% of silicon carbide particles. For example, the mass content of the carbon particles in the first raw material may be 30%, 35%, 40%, 45%, 50%, 55%, 60%, etc. For example, the mass content of the second resin powder in the first raw material may be 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc. In some specific embodiments, the first raw material also includes silicon carbide particles. In this case, based on the total mass of the first raw material, the first raw material includes 30% to 60% of the carbon particles, 20% to 50% of the second resin powder, and 10% to 40% of the silicon carbide particles. For example, the mass percentage of silicon carbide particles in the first raw material can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, etc. By controlling the content of the above substances within the above ranges, the toughness and strength of the nanoporous region of the brake disc can be appropriately controlled, and a higher dynamic friction coefficient can be achieved, thereby improving the performance of the brake disc.

[0063] In one embodiment, in step S02, the first raw material is pressurized and solidified at 130° C. to 160° C. to obtain a block of the first raw material. For example, the pressurized and solidified temperature may be 130° C., 135° C., 140° C., 145° C., 150° C., 155° C., 160° C., etc.

[0064] In one embodiment, in step S02, the first raw material is crushed and then sieved through a 50-400 mesh screen. For example, the mesh size of the screen can be 50, 80, 100, 120, 150, 180, 200, 220, 250, 280, 300, 350, 380, 400, etc. Controlling the mesh size within the above range facilitates mixing of the second raw material with the carbon fiber reinforced resin strips and the third resin powder, thereby facilitating the subsequent regulation of the distribution of the first and second material distribution zones, and thus facilitating the control of the parameters of the nanoporous zone of the brake disc.

[0065] In one embodiment, in step S03, the second raw material, the carbon fiber reinforced resin strips, the third resin powder, and the solvent are mixed and heated and stirred to completely volatilize the solvent; wherein the heating and stirring temperature is 50°C to 70°C. For example, the heating and stirring temperature can be 50°C, 55°C, 60°C, 65°C, 70°C, etc. In some embodiments of the present application, the solvent includes but is not limited to alcohol.

[0066] In one embodiment, in step S03, based on the total mass of the mixture, the mixture comprises 20% to 50% of the carbon fiber reinforced resin strips, 20% to 40% of the second raw material, and 20% to 40% of the third resin powder. Exemplarily, the mass content of the carbon fiber reinforced resin strips in the mixture can be 20%, 25%, 30%, 35%, 40%, 45%, 50%, etc. Exemplarily, the mass content of the second raw material in the mixture can be 20%, 25%, 30%, 35%, 40%, etc. Exemplarily, the mass content of the third resin powder in the mixture can be 20%, 25%, 30%, 35%, 40%, etc. By controlling the mass content of the carbon fiber reinforced resin strips, the second raw material, and the third resin powder within the above ranges, the proportion of the nanoporous region in the brake disc can be controlled to be within a relatively suitable range, thereby ensuring that the brake disc has both good toughness and good strength, and the resulting brake disc has both good braking performance and a long service life.

[0067] In one embodiment, in step S03, the mixed material is crushed and then sieved through a 15-30 mesh screen. This allows the particle size of the material to be controlled within an appropriate range, and thus the size of the second material partition in the brake disc blank to be controlled within an appropriate range. Furthermore, upon successfully producing the brake disc provided by this application, the size of the nanoporous region can be controlled within an even more appropriate range to ensure better overall performance.

[0068] In one embodiment, in step S04, the brake disc blank is held at a holding temperature of 800°C to 1200°C for 2 to 6 hours under a protective atmosphere. For example, the holding temperature may be 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1100°C, 1050°C, 1200°C, etc. For example, the holding time may be 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, etc.

[0069] In one embodiment, in step S04 , the siliconizing treatment may be a liquid phase siliconizing treatment of the brake disc blank.

[0070] In one embodiment, in step S04, after the siliconizing treatment, the brake disc is further subjected to post-processing to obtain a brake disc that meets actual use requirements. The post-processing process includes flat grinding of the brake disc surface.

[0071] The present application also provides a braking system including the brake disc provided in the present application. Due to the use of the carbon-ceramic brake disc provided in the present application, the braking system has a better braking effect, higher reliability, and longer service life.

[0072] In one embodiment, the brake system includes a carbon-ceramic brake disc, a brake caliper bracket, a brake caliper housing, and a friction pad.

[0073] The embodiment of the present application provides a vehicle, including the braking system provided by the present application. Due to the braking system provided by the present application, the vehicle has good market competitiveness.

[0074] In one embodiment, the transportation vehicle includes a vehicle and an airplane; wherein the vehicle includes a car and a rail transit train.

[0075] The technical solution of this application is further described in detail below with multiple embodiments.

[0076] Example 1

[0077] (1) A 12K carbon fiber tow was immersed in a solution of a first resin (specifically a phenolic resin) with a solid content of 50%. After being taken out, it was dried at 80°C and cured in an environment of 150°C. It was then cut into carbon fiber reinforced resin strips with a length of 2 cm.

[0078] (2) Carbon particles (specifically graphite) with a particle size of 50:50 by mass and a second resin powder (specifically phenolic resin) are uniformly mixed in a V-type mixer to obtain a first raw material; the first raw material is then transferred to a mold and pressurized and cured at 150° C. to obtain a block of the first raw material, which is then crushed and sieved with a 100-mesh sieve to obtain a second raw material.

[0079] (3) Dispersing carbon fiber reinforced resin strips, the second raw material, and the third resin powder in a mass ratio of 40:30:30 in a solvent (specifically alcohol) and heating and stirring at 60°C for 1 hour to completely evaporate the solvent to obtain a mixture; crushing the mixture and sieving it with a 20-mesh membrane screen, and then transferring it to a mold and pressurizing and curing it at 150°C to obtain a brake disc blank.

[0080] (4) The brake disc blank is kept at 1000° C. for 4 hours in a nitrogen atmosphere, and then the carbonized brake disc blank is subjected to liquid phase siliconization, and finally surface processing to obtain a brake disc. The brake disc includes a dense region and a plurality of nanoporous regions spaced apart and dispersed in the dense region.

[0081] Example 2

[0082] The difference from Example 1 is that in step (2), the first raw material includes carbon particles, second resin powder, and silicon carbide particles in a mass ratio of 30:50:20, wherein the particle size of the silicon carbide particles is 0.5 μm.

[0083] Example 3

[0084] The difference from Example 2 is that in step (2), the first raw material includes carbon particles, second resin powder and silicon carbide particles in a mass ratio of 60:20:20.

[0085] Example 4

[0086] The difference from Example 2 is that in step (2), the first raw material includes carbon particles, second resin powder and silicon carbide particles in a mass ratio of 30:50:20.

[0087] Example 5

[0088] The difference from Example 2 is that in step (2), the first raw material includes carbon particles and the second resin powder in a mass ratio of 80:20.

[0089] Example 6

[0090] The difference from Example 2 is that in step (2), the first raw material includes carbon particles and the second resin powder in a mass ratio of 20:80.

[0091] Example 7

[0092] The difference from Example 2 is that in step (3), the mixture includes carbon fiber reinforced resin strips, the second raw material and the third resin powder in a mass ratio of 20:40:40.

[0093] Example 8

[0094] The difference from Example 2 is that in step (3), the mixture includes carbon fiber reinforced resin strips, the second raw material and the third resin powder in a mass ratio of 50:20:30.

[0095] Example 9

[0096] The difference from Example 2 is that in step (3), the mixture includes carbon fiber reinforced resin strips, the second raw material and the third resin powder in a mass ratio of 60:10:40.

[0097] Example 10

[0098] The difference from Example 2 is that in step (3), the mixture includes carbon fiber reinforced resin strips, the second raw material and the third resin powder in a mass ratio of 10:50:40.

[0099] Example 11

[0100] The difference from Example 2 is that in step (3), the blocky first raw material is crushed and then sieved using a 500-mesh sieve; in step (3), the crushed mixture is sieved using a 50-mesh sieve.

[0101] Example 12

[0102] The difference from Example 2 is that in step (3), the blocky first raw material is crushed and then sieved with a 30-mesh sieve; in step (3), the crushed mixture is sieved with a 10-mesh sieve.

[0103] In order to highlight the beneficial effects of the embodiments of the present application, the following comparative examples are provided.

[0104] Comparative Example 1

[0105] (1) 2 cm long 12K short carbon fibers were mixed evenly with phenolic resin powder, carbon powder, and silicon carbide powder, and then placed in a mold for pressurized curing to obtain a molded blank. The mass ratio of carbon fibers: phenolic resin: carbon powder: silicon carbide powder was 40:45:9:6.

[0106] (2) Carbonize the molded body at a temperature of 1000°C for 4 hours in a nitrogen atmosphere.

[0107] (3) The carbonized blank is subjected to liquid phase siliconization and processing to obtain a brake disc.

[0108] Performance Testing

[0109] (1) The brake disc sample was pretreated to expose its cross section, and the pore size of the nanoporous region of the brake disc was measured using SEM. An SEM photograph of a cross section of the brake disc of Example 2 is shown in FIG2 .

[0110] (2) Determine the density and porosity of the brake disc according to the provisions of GB / T 1966;

[0111] (3) Determine the bending strength of the brake disc in accordance with the provisions of GB / T 6569;

[0112] (4) Determine the interlaminar shear strength of the brake disc in accordance with ASTM D2344 / D2344M-13;

[0113] (5) Determine the compressive strength of the brake disc in accordance with the provisions of GB / T 34559;

[0114] (6) Determine the impact toughness of the brake disc in accordance with the provisions of GB / T 14389;

[0115] (7) Use TC-3000 thermal constant tester to test the thermal conductivity of the brake disc according to GJB1201.1-91;

[0116] (8) The dynamic friction coefficient of the brake disc is tested using an MM-1000 friction tester. The effective friction surface of the test ring has an outer diameter of D75mm and an inner diameter of D55mm × 10mm, and a specific pressure of 98N / cm 2 , inertia is 3kgf·cm·s 2 , linear speed is 25m / s.

[0117] Table 1

[0118] Table 2

[0119] Combining the parameters in Tables 1 and 2, it can be seen that the impact toughness and bending strength of the brake disc provided in the embodiment of the present application are significantly higher than those of the comparative brake disc. In addition, the parameters such as the compressive strength, shear strength, thermal conductivity, and dynamic friction coefficient of the brake disc provided in the embodiment also meet the requirements of use.

[0120] In addition, by comparing the data between Example 1 and Example 5, it can be found that when the mass ratio of the carbon powder to the second resin powder in the first raw material is within the range further suggested in this application, the performance of the brake disc obtained is better. By comparing the data of Example 1 and Examples 2-4, it is not difficult to see that when the first raw material also contains silicon carbide and the content of each raw material is within the range further suggested in this application, the mechanical strength and dynamic friction coefficient of the brake disc are better. By comparing the data of Examples 7-8 and Examples 9-10, it can be found that when the content of each substance in the second raw material is within the range further suggested in this application, the overall performance of the brake disc is better. By comparing the data of Example 2 with that of Examples 11-12, it is not difficult to find that the mesh size of the first raw material and the second raw material after crushing will also affect the performance of the final brake disc. When the mesh size of the crushed and sieved materials meets the parameters further suggested in the examples of this application, it is easier to obtain a brake disc with balanced performance and better performance.

[0121] The above is an exemplary embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made thereto without departing from the principles of the present application. These improvements and modifications are also considered to be within the scope of protection of the present application.

Claims

1. A brake disc (1), characterized in that: It comprises a dense region (10) and a plurality of nanoporous regions (20) spaced apart and distributed in the dense region (10); The dense region (10) comprises carbon fiber reinforced silicon carbide material, and the nanoporous region (20) comprises cracked carbon in a continuous phase and carbon particles distributed in the cracked carbon; the pore size of the nanoporous region (20) ranges from 10 nm to 100 nm, and the porosity ranges from 15% to 30%.

2. The brake disc (1) according to claim 1, characterized in that The size of the nanoporous region (20) ranges from 30 μm to 500 μm.

3. The brake disc (1) according to claim 1 or 2, characterized in that: Based on the volume of the brake disc (1), the sum of the volume percentages of the plurality of nanoporous regions (20) ranges from 5% to 30%.

4. The brake disc (1) according to any one of claims 1 to 3, characterized in that: Based on the total mass of the nanoporous region (20), the nanoporous region (20) comprises 30% to 70% of the carbon particles, 10% to 40% of the cracked carbon, and 0% to 50% of the silicon carbide particles.

5. The brake disc (1) according to claim 4, characterized in that In the nanoporous region (20), the mass percentage of the silicon carbide particles is 5% to 50%.

6. The brake disc (1) according to any one of claims 1 to 5, characterized in that The particle size of the carbon particles is 0.1 μm to 10 μm.

7. The brake disc (1) according to any one of claims 1 to 6, characterized in that The D50 particle size of the carbon particles is 0.3 μm to 10 μm.

8. The brake disc (1) according to claim 4 or 5, characterized in that The D50 particle size of the silicon carbide particles is 0.3 μm to 20 μm.

9. The brake disc (1) according to any one of claims 1 to 8, characterized in that The porosity of the brake disc (1) is in the range of 1%-5%.

10. A method for preparing a brake disc (1), characterized in that: The following steps are involved: (1) immersing a carbon fiber tow into a solution of a first resin, taking it out, drying, curing, and shearing it to obtain a carbon fiber reinforced resin strip; (2) heating and pressurizing a first raw material including carbon particles and a second resin powder in a mold to solidify the first raw material, and then crushing and sieving the first raw material to obtain a granular second raw material; (3) mixing the carbon fiber reinforced resin strip, the second raw material, the third resin powder, and the solvent, heating and stirring until the solvent evaporates to obtain a mixture; crushing and sieving the mixture, transferring it to a mold for heating and heating Pressing and curing to obtain a brake disc blank; wherein the brake disc blank comprises a first material distribution area and a plurality of second material distribution areas dispersed in the first material distribution area, the first material distribution area comprises the carbon fiber reinforced resin strip and the third resin powder; the second material distribution area comprises the second raw material and the third resin powder; (4) performing a carbonization treatment on the brake disc blank under a protective atmosphere; and then performing a siliconizing treatment to obtain the brake disc (1); The brake disc (1) comprises a dense area (10) and a plurality of nanoporous areas (20) spaced apart in the dense area (10); the dense area (10) comprises a carbon fiber reinforced silicon carbide material, and the nanoporous area (20) comprises cracked carbon in a continuous phase and the carbon particles dispersed in the cracked carbon; the pore size of the nanoporous area (20) ranges from 10 nm to 100 nm, and the porosity ranges from 15% to 30%.

11. The preparation method according to claim 10, characterized in that: Based on the total mass of the mixture, the mixture includes 20% to 50% of the carbon fiber reinforced resin strips, 20% to 40% of the second raw material, and 20% to 40% of the third resin powder; The length of the carbon fiber reinforced resin strip is 0.5 cm to 3 cm.

12. The preparation method according to claim 10, characterized in that: Based on the total mass of the first raw material, the first raw material includes 30% to 60% of the carbon particles, 20% to 50% of the second resin powder, and 0% to 40% of silicon carbide particles.

13. The preparation method according to any one of claims 10 to 12, characterized in that: In step (2), the sieving is performed using a sieve of 50 to 400 meshes.

14. The preparation method according to any one of claims 10 to 13, characterized in that: In step (3), the sieving is performed using a sieve with a mesh size of 15 to 30.

15. A braking system, characterized in that: The brake system comprises a brake disc (1) according to any one of claims 1 to 9.

16. A means of transport, characterized in that: The vehicle comprises a braking system as claimed in claim 15 .

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