Brake disc with high fracture toughness and method for manufacturing same

Abstract

The application provides a brake disc with high fracture toughness, which comprises resin carbon fiber bundles, silicon carbide and silicon, wherein the resin carbon fiber bundles comprise resin carbon, carbon fibers and pores in the resin carbon fiber bundles, the content of the carbon fibers in the resin carbon fiber bundles is 50-75 vol%, the content of the resin carbon is 24-49 vol% and the content of the pores is 1-10 vol%. The brake disc with high fracture toughness protects the carbon fibers by using resin carbon, the interface between the resin carbon and the carbon fibers is a strong interface, the brake disc is insufficient in toughness, part of weak interfaces, i.e. pores, are introduced to improve the toughness of the brake disc matrix. In the use process of the brake disc, cracks are first generated in the silicon carbide or the silicon and then expand into the fiber bundles. Since the resin carbon and the carbon fibers are strong interfaces, the cracks will not deflect on the interface between the resin carbon and the carbon fibers. When part of slit pores are introduced, the cracks will deflect when reaching the pore positions, so that the fracture toughness of the brake disc is greatly increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of brake disc manufacturing, and particularly relates to a brake disc with high fracture toughness and a preparation method thereof. BACKGROUND

[0002] The brake disc is an important part installed on a vehicle such as an automobile or a motorcycle, and is used for braking the vehicle. It is usually located between the wheels and cooperates with the brake caliper, brake pad and the like in the brake system. The brake disc is part of the automobile brake system. In addition to the brake disc, the disc brake also has parts such as the caliper, brake pad and brake throat pipe. The brake disc rotates with the wheel. The brake pad is installed in the caliper and is stationary relative to the brake disc. When the driver steps on the brake, the brake oil in the brake throat pipe acts as a hydraulic medium to apply pressure to the piston in the caliper, so that the brake pad tightly holds the brake disc, and the brake disc stops rotating through friction, thereby achieving the effect of deceleration or parking. The carbon ceramic brake disc is prepared by using carbon fiber reinforced silicon carbide material, and the protection of the carbon fiber is the key to ensuring the strength of the material. At present, the carbon fiber is usually protected by chemical vapor deposition pyrolytic carbon. The chemical vapor deposition has good protection effect on the carbon fiber, but the preparation cycle is long, and the difference between the inner and outer deposition thicknesses of the deposited sample is large, so the dynamic balance of the prepared carbon ceramic disc is poor, and the sample needs to be processed to obtain a sample with dynamic balance meeting the requirements.

[0003] Therefore, the present application provides a brake disc with high fracture toughness. In view of the problem of insufficient toughness of the brake disc after CVI treatment, resin carbon is used to protect the carbon fiber, and part of the weak interface is introduced to ensure the high toughness of the brake disc. SUMMARY

[0004] The present application aims to provide a brake disc with high fracture toughness to solve the problem of insufficient toughness of the brake disc after CVI treatment.

[0005] To achieve this purpose, the present application provides a brake disc with high fracture toughness, which comprises resin carbon fiber bundles, silicon carbide and silicon. The resin carbon fiber bundle comprises resin carbon, carbon fiber and pores in the resin carbon fiber bundle. The content of the carbon fiber in the resin carbon fiber bundle is 50-75 vol%, the content of the resin carbon is 24-49 vol%, and the content of the pores is 1-10 vol%.

[0006] Preferably, the length of the pores is 100-1000 μm, and the width is 1-30 μm.

[0007] Preferably, the optical extinction angle of the resin carbon is less than 18°.

[0008] Preferably, the resin carbon fiber bundle content of the brake disc with high fracture toughness is 40-60 vol%, the silicon carbide content is 35-55 vol%, and the silicon content is 5-15 vol%.

[0009] Preferably, the average number of fibers of the resin carbon fiber bundle is 2000-7000.

[0010] Preferably, the length of the resin carbon fiber bundle is 8-15 mm.

[0011] The application also provides a preparation method of the brake disc with high fracture toughness, and the preparation method is as follows:

[0012] S1: mixing phenolic resin alcohol solution, carbon fiber bundle and carbon powder according to a predetermined proportion, and obtaining a mixture after drying;

[0013] S2: placing the mixture into a mold for hot pressing to obtain a preform, the hot pressing temperature is 120-150°C, the pressure is 3-6 MPa, and the holding time is 2-5 h;

[0014] S3: taking the cured preform out of the mold, placing it into a carbonization furnace for carbonization to obtain a first carbonized body, and the carbonization temperature is 900-1100°C;

[0015] S4: placing the first carbonized body into a soaking solution while performing vacuumizing treatment; the soaking solution comprises 35-49 wt% of phenolic resin, 50 wt% of alcohol and 1-15 wt% of stearic acid;

[0016] S5: drying the soaked first carbonized body, and then performing carbonization treatment again to obtain a second carbonized body, and the carbonization temperature is 900-1100°C;

[0017] S6: repeating the above S4 and S5 steps to obtain an Nth carbonized body, N is a natural number greater than 2, and N is the implementation number of the above S5 step plus one;

[0018] S7: placing the Nth carbonized body into a siliconizing furnace for siliconizing treatment to obtain a siliconized body, the siliconizing temperature is 1600-1800°C, and the holding time is 2-4 h; and after the siliconizing treatment, the siliconized body is polished to obtain the brake disc with high fracture toughness.

[0019] Preferably, the content of the phenolic resin alcohol solution in the mixture is 50%, the content of the carbon fiber bundle is 35 vol%, and the content of the carbon powder is 15 vol%.

[0020] Preferably, the vacuumizing time in the S4 step is 10-30 min.

[0021] Preferably, the density of the Nth carbonized body is greater than 1.3 g / cm 3 .

[0022] Beneficial effects: the application provides a brake disc with high fracture toughness, resin carbon is used to protect carbon fibers, the interface between resin carbon and carbon fibers is a strong interface, the brake disc toughness is insufficient, part of weak interface, i.e. pores, is introduced to improve the toughness of the brake disc matrix, a certain number of pores exist in the resin carbon fiber bundle, cracks are first generated in silicon carbide or silicon during the use of the brake disc and expand into the fiber bundle, since the resin carbon and carbon fibers are strong interfaces, the cracks will not deflect on the interface between the resin carbon / carbon fibers, when part of the slit pores is introduced, the cracks will deflect when reaching the pore position, thereby greatly increasing the fracture toughness of the brake disc. The application also provides a preparation method of the brake disc with high fracture toughness, a liquid pore-forming agent (stearic acid) incompatible with phenolic resin is added to the soaking solution, the stearic acid will exist in the fiber bundle during resin curing, and after carbonization, pores coated by resin carbon and carbon fibers are formed in the fiber bundle. Since the content of stearic acid is much lower than that of resin, the pores formed are often closed pores, and it is difficult to fill these pores through multiple impregnation-carbonization, the porosity in the resin carbon fiber bundle can be adjusted by adjusting the component ratio of the soaking solution, so as to adjust the toughness and strength ratio of the brake disc. The whole production process is simple and easy to produce, the resin carbon is used to protect the carbon fibers instead of CVI to protect the carbon fibers, and the amount of carbon fibers is effectively reduced, thereby reducing the material cost. DETAILED DESCRIPTION

[0023] The embodiments described below are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0024] The application provides a brake disc with high fracture toughness, which comprises a resin carbon fiber bundle, silicon carbide and silicon, the resin carbon fiber bundle comprises resin carbon, carbon fibers and pores in the resin carbon fiber bundle, the content of carbon fibers in the resin carbon fiber bundle is 50-75 vol%, the content of resin carbon is 24-49 vol%, and the content of pores is 1-10 vol%.

[0025] The length of the pores is 100-1000 microns, and the width is 1-30 microns.

[0026] The optical extinction angle of the resin carbon is less than 18 degrees.

[0027] The content of the resin carbon fiber bundle of the brake disc with high fracture toughness is 40-60 vol%, the content of silicon carbide is 35-55 vol%, and the content of silicon is 5-15 vol%.

[0028] The average fiber number of the resin carbon fiber bundle is 2000-7000.

[0029] The length of the resin carbon fiber bundle is 8-15mm.

[0030] The application also provides a preparation method of the brake disc with high fracture toughness, and the preparation method is as follows:

[0031] S1: mixing phenolic resin alcohol solution, carbon fiber bundle and carbon powder according to a predetermined proportion, and obtaining a mixture after drying;

[0032] S2: placing the mixture into a mold for hot pressing to obtain a pre-form, the hot pressing temperature is 120-150℃, the pressure is 3-6MPa, and the holding time is 2-5h;

[0033] S3: taking out the cured pre-form from the mold, placing it into a carbonization furnace for carbonization to obtain a first carbonized body, the carbonization temperature is 900-1100℃;

[0034] S4: placing the first carbonized body into a soaking solution while performing vacuumizing treatment; the soaking solution comprises 35-49wt% of phenolic resin, 50wt% of alcohol and 1-15wt% of stearic acid;

[0035] S5: drying the soaked first carbonized body, and then performing carbonization treatment again to obtain a second carbonized body, the carbonization temperature is 900-1100℃;

[0036] S6: repeating the above S4 and S5 steps to obtain an Nth carbonized body, N is a natural number greater than 2, and N is the implementation number of the above S5 step plus one;

[0037] S7: placing the Nth carbonized body into a siliconizing furnace for siliconizing treatment to obtain a siliconized body, the siliconizing temperature is 1600-1800℃, and the holding time is 2-4h; after the siliconizing treatment, the siliconized body is polished to obtain the brake disc with high fracture toughness.

[0038] In the mixture, the content of the phenolic resin alcohol solution is 50%, the content of the carbon fiber bundle is 35vol%, and the content of the carbon powder is 15vol%.

[0039] The vacuumizing time in the S4 step is 10-30min.

[0040] The density of the Nth carbonized body is greater than 1.3g / cm 3 .

[0041] Example 1

[0042] The example provides a brake disc with high fracture toughness, and the preparation steps are as follows:

[0043] S1: mixing phenolic resin alcohol solution (50wt% alcohol solution), carbon fiber bundle and carbon powder according to a predetermined proportion, and obtaining a mixture after drying, wherein the content of the phenolic resin alcohol solution in the mixture is 50%, the content of the carbon fiber bundle is 35vol%, and the content of the carbon powder is 15vol%;

[0044] S2: placing the mixture into a mold for hot pressing to obtain a pre-form, wherein the hot pressing temperature is 150°C, the pressure is 5MPa, and the holding time is 3h;

[0045] S3: taking the cured pre-form out of the mold, placing it into a carbonization furnace for carbonization to obtain a first carbonized body, wherein the carbonization temperature is 1000°C;

[0046] S4: placing the first carbonized body into a soaking solution while performing vacuumizing treatment, wherein the vacuumizing time is 30min; the soaking solution comprises 35wt% of phenolic resin, 50wt% of alcohol and 15wt% of stearic acid;

[0047] S5: performing drying treatment on the soaked first carbonized body, and then performing carbonization treatment again to obtain a second carbonized body, wherein the carbonization temperature is 1000°C;

[0048] S6: repeating the above steps S4 and S5 to obtain an Nth carbonized body, wherein N is a natural number greater than 2, N is the number of times of performing the step S5 plus one, and the density of the Nth carbonized body reaches 1.35g / cm 3 ;

[0049] S7: placing the Nth carbonized body into a silicon infiltration furnace for silicon infiltration treatment to obtain a siliconized body, wherein the silicon infiltration temperature is 1600°C, and the holding time is 2h; and performing polishing on the siliconized body after the silicon infiltration treatment to obtain the brake disc with high fracture toughness.

[0050] Example 2

[0051] The embodiment provides a brake disc with high fracture toughness, and the preparation steps are as follows:

[0052] S1: mixing phenolic resin alcohol solution (50wt% alcohol solution), carbon fiber bundle and carbon powder according to a predetermined proportion, and obtaining a mixture after drying, wherein the content of the phenolic resin alcohol solution in the mixture is 50%, the content of the carbon fiber bundle is 35vol%, and the content of the carbon powder is 15vol%;

[0053] S2: placing the mixture into a mold for hot pressing to obtain a pre-form, wherein the hot pressing temperature is 150°C, the pressure is 5MPa, and the holding time is 3h;

[0054] S3: taking the cured pre-form out of the mold, placing it into a carbonization furnace for carbonization to obtain a first carbonized body, wherein the carbonization temperature is 1000°C;

[0055] S4: the first carbonized body is put into a soaking solution while being subjected to vacuumizing treatment for 30 min; the soaking solution comprises 45 wt% of phenolic resin, 50 wt% of alcohol and 5 wt% of stearic acid;

[0056] S5: the first carbonized body after soaking is subjected to drying treatment, and then is subjected to carbonization treatment again to obtain a second carbonized body, the carbonization temperature being 1000°C;

[0057] S6: the above steps S4 and S5 are repeated to obtain an Nth carbonized body, N being a natural number greater than 2, N being the number of times of implementation of the above step S5 plus 1, the density of the Nth carbonized body reaching 1.35 g / cm 3 ;

[0058] S7: the Nth carbonized body is put into a silicon infiltration furnace to perform silicon infiltration treatment to obtain a siliconized body, the silicon infiltration temperature being 1600°C, and the holding time being 2 h; after the silicon infiltration treatment, the siliconized body is polished to obtain the brake disc with high fracture toughness.

[0059] Embodiment 3

[0060] The embodiment provides a brake disc with high fracture toughness, and the preparation steps are as follows:

[0061] S1: a phenolic resin alcohol solution (50 wt% alcohol solution), a carbon fiber bundle and carbon powder are mixed according to a predetermined proportion, and after drying, a mixture is obtained, the content of the phenolic resin alcohol solution in the mixture being 50%, the content of the carbon fiber bundle being 35 vol% and the content of the carbon powder being 15 vol%;

[0062] S2: the mixture is put into a mold to perform hot pressing to obtain a preform, the hot pressing temperature being 150°C, the pressure being 5 MPa, and the holding time being 3 h;

[0063] S3: the cured preform is taken out of the mold, is put into a carbonization furnace to perform carbonization to obtain a first carbonized body, the carbonization temperature being 1000°C;

[0064] S4: the first carbonized body is put into a soaking solution while being subjected to vacuumizing treatment for 30 min; the soaking solution comprises 45 wt% of phenolic resin, 50 wt% of alcohol and 5 wt% of stearic acid;

[0065] S5: the first carbonized body after soaking is subjected to drying treatment, and then is subjected to carbonization treatment again to obtain a second carbonized body, the carbonization temperature being 1000°C;

[0066] S6: the above steps S4 and S5 are repeated to obtain an Nth carbonized body, N being a natural number greater than 2, N being the number of times of implementation of the above step S5 plus 1, the density of the Nth carbonized body reaching 1.35 g / cm3 ;

[0067] S7: Put the Nth carbonized body into a silicon infiltration furnace for silicon infiltration treatment to obtain a siliconized body, the silicon infiltration temperature is 1600℃, and the holding time is 2h; after the silicon infiltration treatment, the siliconized body is polished to obtain the brake disc with high fracture toughness.

[0068] Example 4

[0069] The embodiment provides a brake disc with high fracture toughness, and the preparation steps are as follows:

[0070] S1: A phenolic resin alcohol solution (50wt% alcohol solution), a carbon fiber bundle and carbon powder are mixed according to a predetermined proportion, and after drying, a mixture is obtained, wherein the content of the phenolic resin alcohol solution in the mixture is 50%, the content of the carbon fiber bundle is 35vol%, and the content of the carbon powder is 15vol%;

[0071] S2: The mixture is put into a mold for hot pressing to obtain a preform, the hot pressing temperature is 150℃, the pressure is 5MPa, and the holding time is 3h;

[0072] S3: The cured preform is taken out of the mold and put into a carbonization furnace for carbonization to obtain a first carbonized body, the carbonization temperature is 1000℃;

[0073] S4: The first carbonized body is put into a soaking solution, and vacuumizing treatment is simultaneously performed, the vacuumizing time is 30min; the soaking solution comprises 49wt% of phenolic resin, 50wt% of alcohol and 1wt% of stearic acid;

[0074] S5: The first carbonized body after soaking is dried and treated, and then carbonization treatment is performed again to obtain a second carbonized body, the carbonization temperature is 1000℃;

[0075] S6: The Nth carbonized body is obtained by repeating the above steps S4 and S5, N is a natural number greater than 2, N is the implementation number of the above step S5 plus one, and the density of the Nth carbonized body reaches 1.35g / cm 3 ;

[0076] S7: Put the Nth carbonized body into a silicon infiltration furnace for silicon infiltration treatment to obtain a siliconized body, the silicon infiltration temperature is 1600℃, and the holding time is 2h; after the silicon infiltration treatment, the siliconized body is polished to obtain the brake disc with high fracture toughness.

[0077] Comparative Example 1

[0078] The comparative example provides a brake disc, and the preparation steps are as follows:

[0079] S1: mixing phenolic resin alcohol solution (50wt% alcohol solution), carbon fiber bundle and carbon powder according to a predetermined proportion, and obtaining a mixture after drying, wherein the content of the phenolic resin alcohol solution in the mixture is 50%, the content of the carbon fiber bundle is 35vol%, and the content of the carbon powder is 15vol%;

[0080] S2: placing the mixture into a mold for hot pressing to obtain a pre-form, wherein the hot pressing temperature is 150°C, the pressure is 5MPa, and the holding time is 3h;

[0081] S3: taking the cured pre-form out of the mold, placing it into a carbonization furnace for carbonization to obtain a first carbonized body, wherein the carbonization temperature is 1000°C;

[0082] S4: placing the first carbonized body into a soaking solution while performing vacuumizing treatment, wherein the vacuumizing time is 30min, and the soaking solution comprises 50wt% phenolic resin and 50wt% alcohol;

[0083] S5: performing drying treatment on the soaked first carbonized body, and then performing carbonization treatment again to obtain a second carbonized body, wherein the carbonization temperature is 1000°C;

[0084] S6: repeating the above steps S4 and S5 to obtain an Nth carbonized body, wherein N is a natural number greater than 2, N is the number of times of performing the step S5 plus one, and the density of the Nth carbonized body reaches 1.35g / cm 3 ;

[0085] S7: placing the Nth carbonized body into a siliconizing furnace for siliconizing treatment to obtain a siliconized body, wherein the siliconizing temperature is 1600°C, and the holding time is 2h; and polishing the siliconized body after the siliconizing treatment to obtain the brake disc.

[0086] Comparative Example 2

[0087] The present comparative example provides a brake disc, and the preparation steps thereof are as follows:

[0088] S1: mixing phenolic resin alcohol solution (50wt% alcohol solution), carbon fiber bundle and carbon powder according to a predetermined proportion, and obtaining a mixture after drying, wherein the content of the phenolic resin alcohol solution in the mixture is 50%, the content of the carbon fiber bundle is 35vol%, and the content of the carbon powder is 15vol%;

[0089] S2: placing the mixture into a mold for hot pressing to obtain a pre-form, wherein the hot pressing temperature is 150°C, the pressure is 5MPa, and the holding time is 3h;

[0090] S3: taking the cured pre-form out of the mold, placing it into a carbonization furnace for carbonization to obtain a first carbonized body, wherein the carbonization temperature is 1000°C;

[0091] S4: Put the first carbonized body into a soaking solution, and perform vacuumizing treatment, the vacuumizing time is 30 min; the soaking solution comprises 30 wt% of phenolic resin, 50 wt% of alcohol and 20 wt% of stearic acid;

[0092] S5: Perform drying treatment on the first carbonized body after soaking, and then perform carbonization treatment again to obtain a second carbonized body, the carbonization temperature is 1000℃;

[0093] S6: Repeat the above S4 and S5 steps to obtain an Nth carbonized body, N is a natural number greater than 2, N is the implementation number of the above S5 step plus one, the density of the Nth carbonized body reaches 1.35 g / cm 3 ;

[0094] S7: Put the Nth carbonized body into a silicon infiltration furnace to perform silicon infiltration treatment to obtain a siliconized body, the silicon infiltration temperature is 1600℃, and the holding time is 2 h; after the silicon infiltration treatment, the siliconized body is polished to obtain the brake disc.

[0095] The brake discs prepared in the above examples 1-4 and comparative examples 1-2 are tested. The test method is as follows:

[0096] The sample density is measured by the Archimedes drainage method, and the sample volume is V;

[0097] The resin carbon fiber bundle content is measured by the oxidation method: the sample is placed into a heating furnace at 700℃ for oxidation, and the mass loss before and after oxidation is divided by 1.8 g / cm 3 , to obtain the resin carbon fiber bundle content V cf ;

[0098] Silicon content determination: the oxidized sample is placed into concentrated nitric acid for soaking until the sample mass no longer decreases, and the mass difference before and after the concentrated nitric acid corrosion is divided by 2.33 g / cm 3 , to obtain the silicon content V Si ;

[0099] Silicon carbide content determination: the weight of the sample after acid corrosion is divided by 3.2 g / cm3 to obtain the silicon content V SiC ;

[0100] Carbon fiber bundle inner porosity determination:

[0101] Impact toughness is tested by the impact toughness test method for engineering ceramics in GBT_14389-1993;

[0102] Bending strength is tested by the bending strength test method for fine ceramics in GBT_65669-2006.

[0103] The test data are shown in Table 1.

[0104] Table 1 Brake disc test data of examples 1-4 and comparative examples 1-2

[0105]

[0106] From the above test data, it can be seen that the soaking solution of example 1 contains 15wt% of stearic acid, and proper porosity can be introduced into the resin carbon fiber bundle during the manufacturing process of the brake disc, and the impact toughness of the material reaches 60KJ / m 2 From examples 2-3, it can be seen that the amount of stearic acid in the soaking solution is reduced, and the number of pores in the resin carbon fiber bundle is also reduced. With the decrease of the porosity in the resin carbon fiber bundle, the impact toughness of the material decreases, but the strength increases. In comparative example 1, the carbon fiber bundle does not contain pores, and the bending strength is high, but the impact toughness is very low, which does not meet the use requirements of the brake disc. In comparative example 2, the addition amount of stearic acid is 20%, and because too much stearic acid is added, it is easier to form through holes, and silicon is easy to penetrate, which causes corrosion of the carbon fiber, and the impact toughness and bending strength decrease.

[0107] The above disclosure is only several preferred embodiments of the present application, and of course cannot limit the scope of the rights of the present application, so the equivalent changes made in the scope of the patent application of the present application still fall within the scope of the present application.

Claims

1. A brake disc having high fracture toughness, characterized by, The brake disc with high fracture toughness comprises resin carbon fiber bundles, silicon carbide and silicon, the resin carbon fiber bundle comprises resin carbon, carbon fiber and pores in the resin carbon fiber bundle, the content of carbon fiber in the resin carbon fiber bundle is 50-75vol%, the content of resin carbon is 24-49vol% and the content of pores is 1-10vol%; the content of resin carbon fiber bundle in the brake disc with high fracture toughness is 40-60vol%, the content of silicon carbide is 35-55vol% and the content of silicon is 5-15vol%.

2. The brake disc having high fracture toughness according to claim 1, wherein The length of the pores is 100-1000μm and the width is 1-30μm.

3. The brake disc having high fracture toughness according to claim 1, wherein The optical extinction angle of the resin carbon is less than 18°.

4. The brake disc having high fracture toughness according to Claim 1, wherein The average number of fibers of the resin carbon fiber bundle is 2000-7000.

5. The brake disc having high fracture toughness according to claim 4, wherein The length of the resin carbon fiber bundle is 8-15mm.

6. A method for producing a brake disc having high fracture toughness, for producing a brake disc having high fracture toughness as claimed in any one of claims 1 to 5, characterized in that, The preparation method is as follows: S1: mixing phenolic resin alcohol solution, carbon fiber bundle and carbon powder according to predetermined proportions, and obtaining mixed material after drying; S2: placing the mixed material into a mold for hot pressing to obtain a preform, the hot pressing temperature is 120-150℃, the pressure is 3-6MPa and the holding time is 2-5h; S3: taking the cured preform out of the mold, placing it into a carbonization furnace for carbonization to obtain a first carbonized body, the carbonization temperature is 900-1100℃; S4: placing the first carbonized body into a soaking solution while performing vacuumizing treatment; the soaking solution comprises 35-49wt% of phenolic resin, 50wt% of alcohol and 1-15wt% of stearic acid; S5: drying the soaked first carbonized body, and then performing carbonization treatment again to obtain a second carbonized body, the carbonization temperature is 900-1100℃; S6: repeating the above S4 and S5 steps to obtain an Nth carbonized body, N is a natural number greater than 2, N is the number of times of performing the above S5 step plus one; S7: placing the Nth carbonized body into a silicon infiltration furnace for silicon infiltration treatment to obtain a siliconized body, the silicon infiltration temperature is 1600-1800℃ and the holding time is 2-4h; polishing the siliconized body after the silicon infiltration treatment to obtain the brake disc with high fracture toughness.

7. The method for preparing a brake disc with high fracture toughness according to claim 6, characterized in that: The content of phenolic resin alcohol solution in the mixed material is 50%, the content of carbon fiber bundle is 35vol% and the content of carbon powder is 15vol%.

8. The method for preparing a brake disc with high fracture toughness according to claim 6, characterized in that: The vacuumizing time in the S4 step is 10-30min.

9. The method of claim 6, wherein the brake disc having high fracture toughness is prepared by the steps of: The Nth carbonized body has a density greater than 1.3 g / cm3 3 . ​

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