A high-strength carbon ceramic brake disc and its preparation method

Abstract

The present invention provides a high-strength carbon-ceramic brake disc, comprising 40-60 vol% carbon, 30-55 vol% silicon carbide, and 3-13 vol% silicon. The carbon comprises a resin carbon fiber phase and a deposited carbon fiber phase, wherein the resin carbon fiber phase comprises resin carbon and a skeleton carbon fiber coated with the resin carbon; the deposited carbon fiber phase comprises deposited carbon and a filled carbon fiber coated with the deposited carbon. The resin carbon fiber phase content is 35-55%, and the deposited carbon fiber phase content is 3-15%. The carbon of the high-strength carbon-ceramic brake disc is mainly composed of a resin carbon fiber phase. The fibers are impregnated with resin and cured before being chopped. During chopping and impregnation, the resin carbon fiber phase is protected by the resin, resulting in minimal fiber damage, thereby effectively improving the strength of the brake disc. The present invention also adds a portion of filling fibers that have been chemically vapor deposited but have a smaller fiber bundle k value to the matrix. Due to the presence of the deposited carbon / carbon fiber interface, the deposited carbon fiber phase can exert its crack deflection effect in the product, ensuring the toughness of the material.

Description

Technical Field

[0001] The present invention relates to the technical field of brake disc manufacturing, and in particular to a high-strength carbon ceramic brake disc and a preparation method thereof. Background Art

[0002] The brake disc is a critical component installed in vehicles such as automobiles and motorcycles, used for braking. It is typically located between the wheels and works in conjunction with the brake caliper and brake pads in the braking system. The brake disc is part of a vehicle's braking system. In addition to the brake disc, a disc brake system also includes calipers, brake pads, and brake hoses. The brake disc rotates with the wheel, while the brake pads, mounted inside the caliper, remain stationary relative to the disc. When the driver applies the brakes, the brake fluid in the brake hose acts as a hydraulic medium, applying pressure to the piston inside the caliper, causing the brake pads to grip the disc tightly. Friction stops the disc's rotation, thereby slowing or stopping the vehicle. Brake discs can be categorized into three types based on their material: gray cast iron, carbon-carbon, and carbon-ceramic. Carbon-ceramic brake material, as a new brake material, offers advantages over traditional metal and semi-metallic brake materials, including low density, stable friction coefficient, high braking ratio, corrosion resistance, and long service life. In particular, it resists thermal decay during prolonged braking. It has broad application prospects in brake applications for high-speed trains, automobiles, aircraft, and other applications. Currently, the manufacturing process for carbon-ceramic brake discs is divided into long-fiber and short-fiber processes. The short-fiber process first involves CVI deposition to protect the carbon fibers. The deposited fibers are then chopped, mixed with resin and appropriate additives, and then carbonized and siliconized. The CVI deposited carbon provides good protection for the carbon fibers, but it can easily damage the fibers during chopping. Furthermore, the pressing pressure during hot pressing can damage the CVI fibers, causing them to separate into multiple bundles. During siliconization, the fibers are susceptible to corrosion from silicon, resulting in a decrease in product strength.

[0003] Therefore, a high-strength carbon-ceramic brake disc is proposed to address the problem that chemical vapor deposited carbon fibers are easily damaged during chopping and pressing. The damage to the fiber bundles during chopping and pressing is reduced, and the strength and toughness of the material are improved. Summary of the Invention

[0004] The present invention aims to provide a high-strength carbon ceramic brake disc to solve the problem of insufficient strength and toughness of the brake disc after CVI treatment.

[0005] To achieve this objective, the present invention provides a high-strength carbon-ceramic brake disc comprising 40-60 vol% carbon, 30-55 vol% silicon carbide, and 3-13 vol% silicon. The carbon comprises a resin carbon fiber phase and a deposited carbon fiber phase. The resin carbon fiber phase comprises resin carbon and a skeleton carbon fiber coated with the resin carbon. The deposited carbon fiber phase comprises deposited carbon and a filled carbon fiber coated with the deposited carbon. The resin carbon fiber phase comprises 35-55% and the deposited carbon fiber phase comprises 3-15%.

[0006] Preferably, the content of the skeleton carbon fiber in the resin carbon fiber phase is 40-60%, the content of the resin carbon is 40-60%, and the extinction angle of the resin carbon is less than 18°.

[0007] Preferably, the content of filled carbon fibers in the deposited carbon fiber phase is 35-55%, the content of deposited carbon is 45-65%, and the extinction angle of the deposited carbon is greater than 18°.

[0008] Preferably, the k value of the skeleton carbon fiber is 3-12k, and the k value of the filling carbon fiber is 0.3-3k.

[0009] Preferably, the length of the skeleton carbon fiber is 6-15 mm, and the length of the filling carbon fiber is 5-13 mm.

[0010] Preferably, the skeleton carbon fibers in the resin carbon fiber phase have a plurality of grooves parallel to the length direction of the fibers, and the depth of the grooves is 0.05-1 μm.

[0011] The present invention also provides a method for preparing a high-strength carbon-ceramic brake disc, which is used for the above-mentioned high-strength carbon-ceramic brake disc. The preparation method is as follows:

[0012] S1: oxidizing 3-12k carbon fibers to remove the sizing agent on the surface to obtain oxidized carbon fibers, wherein the oxidation treatment is performed by soaking in concentrated nitric acid or heating in an air atmosphere;

[0013] S2: impregnating the oxidized carbon fibers with resin to obtain pre-impregnated carbon fibers, wherein the volume of the resin after impregnation is 57-75% of the total volume of the resin and the oxidized carbon fibers;

[0014] S3: chopping the prepreg carbon fiber to a length of 6-15 mm to obtain chopped prepreg carbon fiber;

[0015] S4: performing CVI deposition on 0.3-3k carbon fibers to obtain deposited long carbon fibers, wherein the deposited long carbon fibers have a carbon fiber content of 35-55% and a deposited carbon content of 45-65%;

[0016] S5: chopping the deposited long carbon fibers to obtain deposited short carbon fibers with a length of 5-13 mm;

[0017] S6: mixing the deposited short carbon fibers, chopped prepreg carbon fibers, and phenolic resin in a certain proportion to obtain a mixture, placing the mixture into a mold for pressing and curing to obtain a preform at a pressure of 20-30 MPa and a temperature of 120-160° C. for 3-4 hours;

[0018] S7: Carbonizing the preform to obtain a carbonized body at a temperature of 800-1200° C. for 2-6 hours;

[0019] S8: machining the carbide to obtain a brake disc blank, and then placing the brake disc blank into a boron nitride crucible;

[0020] S9: placing the boron nitride crucible containing the brake disc blank into a siliconizing furnace for siliconizing treatment, and then performing surface grinding and outer contour dimension processing to obtain the high-strength carbon ceramic brake disc.

[0021] Preferably, the mixture in step S6 contains 4-17 vol% of deposited short carbon fibers, 40-65 vol% of chopped pre-impregnated carbon fibers, and the remainder is phenolic resin.

[0022] Preferably, silicon powder having a mass 1.1 times that of the brake disc blank is pre-placed in the boron nitride crucible.

[0023] Preferably, the siliconizing treatment temperature is 1600-1800° C., the holding time is 2-6 hours, and the furnace pressure is less than 1000 Pa.

[0024] Beneficial Effects: The present invention provides a high-strength carbon-ceramic brake disc comprising a matrix containing a certain proportion of a resin-carbon fiber phase and a deposited carbon fiber phase. To address the problem that chemical vapor deposited carbon fibers are easily damaged during chopping and pressing, the present invention utilizes a predominantly resin-carbon fiber phase. The fibers are impregnated with resin and cured before being chopped. During chopping and impregnation, the resin-carbon fiber phase is protected by the resin, minimizing fiber damage, thereby effectively improving the strength of the brake disc. Furthermore, the present invention also incorporates a portion of chemical vapor deposited (CVD) filler fiber, but with a lower k value, into the matrix. The deposited carbon fiber phase, due to the presence of a deposited carbon / carbon fiber interface, can deflect cracks in the product, ensuring the material's toughness. This addresses the issue of reduced toughness in brake discs caused by the strong bonding between the resin-carbon and carbon fibers produced after carbonization when fibers are impregnated with resin alone. Furthermore, because the resin-carbon fiber phase accounts for a larger proportion of the brake disc and a smaller proportion of the deposited carbon fiber phase, the skeleton carbon fibers in the resin-carbon fiber phase do not require CVI treatment, significantly reducing production costs. The present invention also proposes a method for preparing high-strength carbon-ceramic brake discs. The matrix is ​​reinforced using short fiber bundles processed in two different ways. The resin-carbon fiber phase minimizes fiber damage during chopping and impregnation due to the protection of the resin, thus ensuring the material's strength. The deposited carbon fiber phase, on the other hand, enhances the material's toughness due to the presence of the deposited carbon / carbon fiber interface. Compared to direct resin impregnation, removing the sizing agent from the fiber surface before impregnation reduces the bond strength between the resin-carbon and carbon fibers, also contributing to improved toughness. Using the resin-carbon fiber phase as the majority of the fiber reduces the amount of CVI-protected carbon fibers required, effectively reducing material costs. DETAILED DESCRIPTION

[0025] The embodiments described below are only some of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] The present invention provides a high-strength carbon-ceramic brake disc comprising 40-60 vol% carbon, 30-55 vol% silicon carbide, and 3-13 vol% silicon. For example, the high-strength carbon-ceramic brake disc comprises 50 vol% carbon, 45 vol% silicon carbide, and 5 vol% silicon; or 55 vol% carbon, 42 vol% silicon carbide, and 3 vol% silicon; or 45 vol% carbon, 50 vol% silicon carbide, and 5 vol% silicon. The carbon comprises a resin carbon fiber phase and a deposited carbon fiber phase. The resin carbon fiber phase comprises resin carbon and a skeleton carbon fiber coated with the resin carbon. The deposited carbon fiber phase comprises deposited carbon and filled carbon fibers coated with the deposited carbon. The resin carbon fiber phase comprises 35-55%, and the deposited carbon fiber phase comprises 3-15%.

[0027] The resin carbon fiber phase contains 40-60% skeleton carbon fibers and 40-60% resin carbon, with an extinction angle of less than 18°. The low extinction angle of the resin carbon indicates a microscopically disordered arrangement of carbon atoms, high rigidity, and good interfacial bonding with the carbon fibers.

[0028] The deposited carbon fiber phase contains 35-55% carbon fiber filling, 45-65% deposited carbon, and an extinction angle of greater than 18°. The large extinction angle of the deposited carbon indicates an orderly arrangement of carbon atoms, similar to a graphite layered structure. The deposited carbon has low rigidity and a weak bond between the deposited carbon and the carbon fibers, which facilitates debonding of the deposited carbon / carbon fiber interface and exerts its toughening effect through weak interfacial deflection.

[0029] The k value of the skeleton carbon fiber is 3-12k, and the k value of the filling carbon fiber is 0.3-3k.

[0030] The length of the skeleton carbon fiber is 6-15 mm, and the length of the filling carbon fiber is 5-13 mm.

[0031] The skeleton carbon fibers in the resin carbon fiber phase have a plurality of grooves parallel to the length direction of the fibers, and the depth of the grooves is 0.05-1 μm.

[0032] The present invention also provides a method for preparing a high-strength carbon-ceramic brake disc, which is used for the above-mentioned high-strength carbon-ceramic brake disc. The preparation method is as follows:

[0033] S1: oxidizing 3-12k carbon fibers to remove the sizing agent on the surface to obtain oxidized carbon fibers, wherein the oxidation treatment is performed by soaking in concentrated nitric acid or heating in an air atmosphere;

[0034] S2: impregnating the oxidized carbon fibers with resin to obtain pre-impregnated carbon fibers, wherein the volume of the resin after impregnation is 57-75% of the total volume of the resin and the oxidized carbon fibers;

[0035] S3: chopping the prepreg carbon fiber to a length of 6-15 mm to obtain chopped prepreg carbon fiber;

[0036] S4: performing CVI deposition on 0.3-3k carbon fibers to obtain deposited long carbon fibers, wherein the deposited long carbon fibers have a carbon fiber content of 35-55% and a deposited carbon content of 45-65%;

[0037] S5: chopping the deposited long carbon fibers to obtain deposited short carbon fibers with a length of 5-13 mm;

[0038] S6: mixing the deposited short carbon fibers, chopped prepreg carbon fibers, and phenolic resin in a certain proportion to obtain a mixture, placing the mixture into a mold for pressing and curing to obtain a preform at a pressure of 20-30 MPa and a temperature of 120-160° C. for 3-4 hours;

[0039] S7: Carbonizing the preform to obtain a carbonized body at a temperature of 800-1200° C. for 2-6 hours;

[0040] S8: machining the carbide to obtain a brake disc blank, and then placing the brake disc blank into a boron nitride crucible;

[0041] S9: placing the boron nitride crucible containing the brake disc blank into a siliconizing furnace for siliconizing treatment, and then performing surface grinding and outer contour dimension processing to obtain the high-strength carbon ceramic brake disc.

[0042] The mixture in step S6 contains 4-17 vol% of deposited short carbon fibers, 40-65 vol% of chopped pre-impregnated carbon fibers, and the remainder is phenolic resin.

[0043] Silicon powder 1.1 times the mass of the brake disc blank is pre-placed in the boron nitride crucible.

[0044] The siliconizing treatment temperature is 1600-1800° C., the holding time is 2-6 hours, and the furnace pressure is less than 1000 Pa.

[0045] Example 1

[0046] This embodiment provides a high-strength carbon ceramic brake disc, and the preparation steps are as follows:

[0047] S1: oxidizing 6k carbon fiber to remove the sizing agent on the surface to obtain oxidized carbon fiber, wherein the oxidation treatment is performed by soaking in concentrated nitric acid;

[0048] S2: impregnating the oxidized carbon fibers with resin to obtain pre-impregnated carbon fibers, wherein the volume of the resin after impregnation is 60% of the total volume of the resin and the oxidized carbon fibers;

[0049] S3: chopping the prepreg carbon fiber to a length of 10 mm to obtain chopped prepreg carbon fiber;

[0050] S4: performing CVI deposition on 1k carbon fibers to obtain deposited long carbon fibers, wherein the deposited long carbon fibers have a carbon fiber content of 50% and a deposited carbon content of 50%;

[0051] S5: chopping the deposited long carbon fibers to obtain deposited short carbon fibers with a length of 7 mm;

[0052] S6: mixing the deposited short carbon fibers, chopped prepreg carbon fibers, and phenolic resin in a certain proportion to obtain a mixture, wherein the mixture comprises 10 vol% of the deposited short carbon fibers, 60 vol% of the chopped prepreg carbon fibers, and the balance of phenolic resin; placing the mixture into a mold for pressing and curing to obtain a preform at a pressure of 20 MPa and a temperature of 130° C. for 3 hours;

[0053] S7: Carbonizing the preform to obtain a carbonized body at a carbonization temperature of 900° C. for 5 hours;

[0054] S8: machining the carbide to obtain a brake disc blank, and then placing the brake disc blank into a boron nitride crucible, wherein silicon powder having a mass 1.1 times that of the brake disc blank is pre-placed in the boron nitride crucible;

[0055] S9: placing the boron nitride crucible containing the brake disc blank into a siliconizing furnace for siliconizing treatment, wherein the siliconizing treatment temperature is 1700° C., the holding time is 3 hours, and the furnace pressure is less than 1000 Pa; after the siliconizing treatment, the surface is polished and the outer contour size is processed to obtain the high-strength carbon ceramic brake disc.

[0056] Example 2

[0057] This embodiment provides a high-strength carbon ceramic brake disc, and the preparation steps are as follows:

[0058] S1: oxidizing 3k carbon fiber to remove the sizing agent on the surface to obtain oxidized carbon fiber, wherein the oxidation treatment is performed by soaking in concentrated nitric acid;

[0059] S2: impregnating the oxidized carbon fibers with resin to obtain pre-impregnated carbon fibers, wherein the volume of the resin after impregnation is 60% of the total volume of the resin and the oxidized carbon fibers;

[0060] S3: chopping the prepreg carbon fiber to a length of 10 mm to obtain chopped prepreg carbon fiber;

[0061] S4: performing CVI deposition on 1k carbon fibers to obtain deposited long carbon fibers, wherein the deposited long carbon fibers have a carbon fiber content of 50% and a deposited carbon content of 50%;

[0062] S5: chopping the deposited long carbon fibers to obtain deposited short carbon fibers with a length of 7 mm;

[0063] S6: mixing the deposited short carbon fibers, chopped prepreg carbon fibers, and phenolic resin in a certain proportion to obtain a mixture, wherein the mixture comprises 10 vol% of the deposited short carbon fibers, 60 vol% of the chopped prepreg carbon fibers, and the balance of phenolic resin; placing the mixture into a mold for pressing and curing to obtain a preform at a pressure of 20 MPa and a temperature of 130° C. for 3 hours;

[0064] S7: Carbonizing the preform to obtain a carbonized body at a carbonization temperature of 900° C. for 5 hours;

[0065] S8: machining the carbide to obtain a brake disc blank, and then placing the brake disc blank into a boron nitride crucible, wherein silicon powder having a mass 1.1 times that of the brake disc blank is pre-placed in the boron nitride crucible;

[0066] S9: placing the boron nitride crucible containing the brake disc blank into a siliconizing furnace for siliconizing treatment, wherein the siliconizing treatment temperature is 1700° C., the holding time is 3 hours, and the furnace pressure is less than 1000 Pa; after the siliconizing treatment, the surface is polished and the outer contour size is processed to obtain the high-strength carbon ceramic brake disc.

[0067] Example 3

[0068] This embodiment provides a high-strength carbon ceramic brake disc, and the preparation steps are as follows:

[0069] S1: oxidizing 6k carbon fiber to remove the sizing agent on the surface to obtain oxidized carbon fiber, wherein the oxidation treatment is performed by soaking in concentrated nitric acid;

[0070] S2: impregnating the oxidized carbon fibers with resin to obtain pre-impregnated carbon fibers, wherein the volume of the resin after impregnation is 60% of the total volume of the resin and the oxidized carbon fibers;

[0071] S3: chopping the prepreg carbon fiber to a length of 10 mm to obtain chopped prepreg carbon fiber;

[0072] S4: performing CVI deposition on 1k carbon fibers to obtain deposited long carbon fibers, wherein the deposited long carbon fibers have a carbon fiber content of 50% and a deposited carbon content of 50%;

[0073] S5: chopping the deposited long carbon fibers to obtain deposited short carbon fibers with a length of 7 mm;

[0074] S6: mixing the deposited short carbon fibers, chopped prepreg carbon fibers, and phenolic resin in a certain proportion to obtain a mixture, wherein the mixture comprises 13 vol% of the deposited short carbon fibers, 65 vol% of the chopped prepreg carbon fibers, and the balance of phenolic resin; placing the mixture into a mold for pressing and curing to obtain a preform at a pressure of 20 MPa and a temperature of 130° C. for 3 hours;

[0075] S7: Carbonizing the preform to obtain a carbonized body at a carbonization temperature of 900° C. for 5 hours;

[0076] S8: machining the carbide to obtain a brake disc blank, and then placing the brake disc blank into a boron nitride crucible, wherein silicon powder having a mass 1.1 times that of the brake disc blank is pre-placed in the boron nitride crucible;

[0077] S9: placing the boron nitride crucible containing the brake disc blank into a siliconizing furnace for siliconizing treatment, wherein the siliconizing treatment temperature is 1700° C., the holding time is 3 hours, and the furnace pressure is less than 1000 Pa; after the siliconizing treatment, the surface is polished and the outer contour size is processed to obtain the high-strength carbon ceramic brake disc.

[0078] Comparative Example 1

[0079] This comparative example provides a carbon-ceramic brake disc, and the preparation steps are as follows:

[0080] S1: 6k carbon fiber is impregnated with resin to obtain pre-impregnated carbon fiber, and the resin volume after impregnation is 60% of the total volume of the resin and oxidized carbon fiber;

[0081] S2: chopping the prepreg carbon fiber to a length of 10 mm to obtain chopped prepreg carbon fiber;

[0082] S3: performing CVI deposition on 1k carbon fibers to obtain deposited long carbon fibers, wherein the deposited long carbon fibers have a carbon fiber content of 50% and a deposited carbon content of 50%;

[0083] S4: chopping the deposited long carbon fibers to obtain deposited short carbon fibers with a length of 7 mm;

[0084] S5: mixing the deposited short carbon fibers, chopped prepreg carbon fibers, and phenolic resin in a certain proportion to obtain a mixture, wherein the mixture comprises 10 vol% of the deposited short carbon fibers, 60 vol% of the chopped prepreg carbon fibers, and the balance of phenolic resin; placing the mixture into a mold for pressing and curing to obtain a preform at a pressure of 20 MPa and a temperature of 130° C. for 3 hours;

[0085] S6: Carbonizing the preform to obtain a carbonized body at a carbonization temperature of 900° C. for 5 hours;

[0086] S7: machining the carbide to obtain a brake disc blank, and then placing the brake disc blank into a boron nitride crucible, wherein silicon powder having a mass 1.1 times that of the brake disc blank is pre-placed in the boron nitride crucible;

[0087] S8: placing the boron nitride crucible containing the brake disc blank into a siliconizing furnace for siliconizing treatment, wherein the siliconizing treatment temperature is 1700° C., the holding time is 3 hours, and the furnace pressure is less than 1000 Pa; after the siliconizing treatment, the surface is polished and the outer contour size is processed to obtain the carbon ceramic brake disc.

[0088] Comparative Example 2

[0089] This comparative example provides a carbon-ceramic brake disc, and the preparation steps are as follows:

[0090] S1: performing CVI deposition on 6k carbon fiber to obtain deposited long carbon fiber, wherein the deposited long carbon fiber has a carbon fiber content of 50% and a deposited carbon content of 50%;

[0091] S2: chopping the deposited long carbon fibers to obtain deposited short carbon fibers with a length of 7 mm;

[0092] S3: mixing the deposited short carbon fibers and phenolic resin in a certain proportion to obtain a mixture, wherein the mixture contains 70 vol% of the deposited short carbon fibers and the balance is phenolic resin; placing the mixture into a mold for pressing and curing to obtain a preform at a pressure of 20 MPa and a temperature of 130° C. for 3 hours;

[0093] S4: carbonizing the preform to obtain a carbonized body at a carbonization temperature of 900° C. for 5 hours;

[0094] S5: machining the carbide to obtain a brake disc blank, and then placing the brake disc blank into a boron nitride crucible, wherein silicon powder having a mass 1.1 times that of the brake disc blank is pre-placed in the boron nitride crucible;

[0095] S6: placing the boron nitride crucible containing the brake disc blank into a siliconizing furnace for siliconizing treatment, wherein the siliconizing treatment temperature is 1700° C., the holding time is 3 hours, and the furnace pressure is less than 1000 Pa; after the siliconizing treatment, the surface is polished and the outer contour size is processed to obtain the high-strength carbon ceramic brake disc.

[0096] The brake discs prepared in Examples 1-3 and Comparative Examples 1-2 were tested. The test method is as follows:

[0097] The impact toughness was tested using the GBT_14389-1993 engineering ceramics impact toughness test method.

[0098] The flexural strength was tested using the GBT_65669-2006 fine ceramic flexural strength test method.

[0099] The extinction angle was tested using a polarizing microscope.

[0100] The test data is shown in Table 1 below.

[0101] Table 1 Brake disc test data of Examples 1-3 and Comparative Examples 1-2

[0102]

[0103] From the above test data, it can be seen from Example 1 that the strength of the composite material prepared by this scheme reaches 125 MPa, which meets the material performance requirements of the composite carbon ceramic disc; Example 2 changes the fiber to 3k and 1k fiber composite, the carbon fiber / matrix interface becomes more, and the toughness of the material becomes greater, but since the contact area between the fiber and silicon becomes larger during siliconization, the amount of silicon carbide produced by the fiber reaction increases, and the strength decreases to a certain extent, but is still greater than 110 MPa; Example 3 increases the amount of fiber added, and the strength and toughness of the material are improved after siliconization.

[0104] In comparative example 1, the fiber has not been oxidized, resulting in a strong bonding between the fiber and the resin carbon. The fiber is not prone to interface separation when it breaks, resulting in stress concentration and brittle fracture of the fiber, and the toughness of the material is reduced. After the fiber is oxidized, the surface grooves that were originally covered by the sizing agent are exposed again. Therefore, in the final product, there will be grooves distributed along the length direction on the fiber surface of the resin carbon fiber phase. The fiber is first oxidized to remove the sizing agent on the surface of the carbon fiber. Many grooves will appear on the carbon fiber (the carbon fiber itself has grooves on its surface, but these grooves will be covered after being treated with the sizing agent). There are two purposes for removing this layer of sizing agent: 1. The sizing agent is not resistant to high temperatures. After carbonization, a gap will be formed between the resin carbon and the carbon fiber, resulting in poor bonding between the carbon fiber and the resin carbon; 2. After removing the sizing agent, grooves will appear on the fiber surface, and these grooves will increase the bonding between the carbon fiber and the resin carbon. The grooves can increase the bonding between the carbon fiber and the resin carbon and increase the strength of the sample, but the toughness will decrease. In the present invention, toughness is provided by CVI carbon / carbon fiber, and better comprehensive performance is achieved by compounding two carbon fibers with different properties. In Example 2, the fibers are all CVI fibers. During the preparation process, the carbon fibers are easily damaged. The 6k fibers may become fibers with a very low k value, resulting in a large contact area between the fiber and silicon, serious fiber corrosion, and a decrease in the mechanical properties of the material.

[0105] The above disclosures are merely some preferred embodiments of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A method for preparing a high-strength carbon ceramic brake disc, characterized in that: The steps include: S1: oxidizing 3-12k carbon fibers to remove the sizing agent on the surface to obtain oxidized carbon fibers, wherein the oxidation treatment is performed by soaking in concentrated nitric acid or heating in an air atmosphere; S2: impregnating the oxidized carbon fibers with resin to obtain pre-impregnated carbon fibers, wherein the volume of the resin after impregnation is 57-75% of the total volume of the resin and the oxidized carbon fibers; S3: chopping the prepreg carbon fiber to a length of 6-15 mm to obtain chopped prepreg carbon fiber; S4: performing CVI deposition on 0.3-3k carbon fibers to obtain deposited long carbon fibers, wherein the deposited long carbon fibers have a carbon fiber content of 35-55% and a deposited carbon content of 45-65%; S5: chopping the deposited long carbon fibers to obtain deposited short carbon fibers with a length of 5-13 mm; S6: mixing the deposited short carbon fibers, chopped prepreg carbon fibers, and phenolic resin in a certain proportion to obtain a mixture, placing the mixture into a mold for pressing and curing to obtain a preform at a pressure of 20-30 MPa and a temperature of 120-160° C. for 3-4 hours; S7: Carbonizing the preform to obtain a carbonized body at a temperature of 800-1200° C. for 2-6 hours; S8: machining the carbide to obtain a brake disc blank, and then placing the brake disc blank into a boron nitride crucible; S9: Put the boron nitride crucible containing the brake disc blank into a siliconizing furnace for siliconizing treatment, and after the siliconizing treatment, perform surface grinding and outer contour dimension processing to obtain a high-strength carbon ceramic brake disc, wherein the high-strength carbon ceramic brake disc contains 40-60vol% carbon, 30-55vol% silicon carbide and 3-13vol% silicon; the carbon includes a resin carbon fiber phase and a deposited carbon fiber phase, the resin carbon fiber phase includes resin carbon and skeleton carbon fibers coated with resin carbon; the deposited carbon fiber phase includes deposited carbon and filled carbon fibers coated with deposited carbon; the content of the resin carbon fiber phase is 35-55%, and the content of the deposited carbon fiber phase is 3-15%.

2. The method for preparing a high-strength carbon ceramic brake disc according to claim 1, characterized in that: The mixture in step S6 contains 4-17 vol% of deposited short carbon fibers, 40-65 vol% of chopped prepreg carbon fibers, and the balance is phenolic resin.

3. The method for preparing a high-strength carbon ceramic brake disc according to claim 1, wherein: Silicon powder 1.1 times the mass of the brake disc blank is pre-placed in the boron nitride crucible.

4. The method for preparing a high-strength carbon ceramic brake disc according to claim 1, wherein: The siliconizing treatment temperature is 1600-1800° C., the holding time is 2-6 hours, and the furnace pressure is less than 1000 Pa.

5. A high-strength carbon ceramic brake disc, characterized in that: It is made by the preparation method of the high-strength carbon ceramic brake disc according to any one of claims 1 to 4, wherein the skeleton carbon fiber content in the resin carbon fiber phase is 40-60%, the resin carbon content is 40-60%, and the extinction angle of the resin carbon is less than 18°.

6. The high-strength carbon ceramic brake disc according to claim 5, characterized in that: The deposited carbon fiber phase contains 35-55% carbon fiber filling content, 45-65% deposited carbon content, and an extinction angle of the deposited carbon is greater than 18°.

7. The high-strength carbon ceramic brake disc according to claim 5, characterized in that: The length of the skeleton carbon fiber is 6-15 mm, and the length of the filling carbon fiber is 5-13 mm.

8. The high-strength carbon-ceramic brake disc according to claim 5, characterized in that: The skeleton carbon fibers in the resin carbon fiber phase have a plurality of grooves parallel to the length direction of the fibers, and the depth of the grooves is 0.05-1 μm.

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