A carbon fiber reinforced silicon carbide brake disc and a method of manufacturing the same

Abstract

The present application provides a kind of carbon fiber reinforced silicon carbide brake disc, the carbon fiber reinforced silicon carbide brake disc includes long fiber area I, long fiber area II, short fiber area III, long fiber area IV and long fiber area V.Long fiber area II and long fiber area IV are the same, long fiber area I and long fiber area V are the same.Long fiber area I and long fiber area V include 1 layer long fiber layer, 2 layer long fiber layer...Nm layer long fiber layer, from surface 1 layer long fiber layer to Nn layer long fiber layer, the content V of silicon carbide in Nn layer long fiber layer reduces with the increase of layer number SiCn 1

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of brake disc manufacturing, and particularly relates to a carbon fiber reinforced silicon carbide brake disc and a preparation method thereof. BACKGROUND

[0002] The brake disc is an important component installed on vehicles such as cars and motorcycles, used for braking the vehicle. It is usually located between the wheels and works in cooperation with the brake calipers, brake pads and other components in the brake system. The brake disc mainly plays a role in reducing speed or emergency stopping during vehicle operation, and is particularly important in terms of life safety in emergency situations. The brake disc is divided into two common types: metal brake disc and carbon ceramic brake disc. The metal brake disc is usually made of cast iron, steel or aluminum alloy, and has durability and high braking performance. The carbon ceramic brake disc is made of carbon fiber and ceramic material, and has the characteristics of being lighter, having higher braking performance and wear resistance, and is suitable for high-performance vehicles. At present, the brake disc is generally prepared by the method of unidirectional cloth and net tire lamination and needling. The carbon fiber content in the green body prepared by the lamination and needling process is low, usually only 30-35 vol%, and the density of the net tire is low, which limits the total carbon fiber content, and the low fiber content limits the further improvement of the material strength. In addition, the needling process is accompanied by fiber damage, which has a great influence on the strength of the fiber composite material. In addition, the components of the carbon ceramic brake disc prepared by the traditional process are basically the same in the thickness direction, which is not conducive to the surface high wear resistance and the material performance requirements of the high strength of the matrix. Therefore, a friction layer is added outside the matrix layer to improve the wear resistance of the brake disc, and the friction layer is prepared separately after the sample is subjected to the gas phase deposition process CVI, then the organic matter in the friction layer green body is removed by carbonization, and finally silicon infiltration is carried out, which is a complicated process and has high cost.

[0003] Therefore, a carbon fiber reinforced silicon carbide brake disc is provided, which adopts carbon fiber square cloth for lamination and hot pressing, reduces the needling process, and adjusts the silicon carbide content in different regions of the brake disc, so that the brake disc has a good friction coefficient while ensuring the overall strength of the brake disc. SUMMARY

[0004] The present application aims to provide a high-performance carbon ceramic brake disc, which sets different carbon fiber contents and fiber orientations in different regions to improve the material strength of the brake disc connection and prevent cracking.

[0005] To achieve this purpose, the present invention provides a carbon fiber reinforced silicon carbide brake disc. The carbon fiber reinforced silicon carbide brake disc includes a long fiber region I, a long fiber region II, a short fiber region III, a long fiber region IV, and a long fiber region V. It is characterized in that the long fiber region II and the long fiber region IV are respectively arranged on both sides of the short fiber region III and are symmetric about the central axis in the height direction of the short fiber region III. The long fiber region I is arranged on the side of the long fiber region II away from the short fiber region III, and the long fiber region V is arranged on the side of the long fiber region IV away from the short fiber region III. The long fiber region I and the long fiber region V are symmetric about the central axis in the height direction of the short fiber region III. The components of the long fiber region II and the long fiber region IV are the same, and the components of the long fiber region I and the long fiber region V are the same. Both the long fiber region I and the long fiber region V include 1 layer of long fiber layer, 2 layers of long fiber layer... Nm layers of long fiber layer. The 1 layer of long fiber layer is away from the short fiber region III and the silicon carbide content in the 1 layer of long fiber layer is V SiCf , the Nm layer of long fiber layer is near the short fiber region III and the silicon carbide content in the Nm layer of long fiber layer is V SiCb , starting from the 1 layer of long fiber layer on the surface to the Nn layer of long fiber layer, the silicon carbide content V in the Nn layer of long fiber layer SiCn decreases with the increase of the number of layers. 1 < Nn < Nm, and its content satisfies the following formula:

[0006]

[0007] where V SiCf is 40 - 70%, V SiCb is 30 - 50%, Nm is any natural number from 4 to 13, and k is an engineering coefficient with a value range of 0.8 - 1.2.

[0008] Preferably, both the long fiber region II and the long fiber region IV include M layers of long fiber layer, M is a natural number greater than 1, the components of each layer of long fiber layer are the same, and each layer of long fiber layer contains 40 - 65% carbon, 30 - 50 vol% silicon carbide, and 3 - 13 vol% silicon.

[0009] Preferably, the short fiber region III is a short fiber layer, the carbon content of the short fiber layer is 35 - 60%, the silicon carbide content is 35 - 55 vol%, and the silicon content is 3 - 13 vol%.

[0010] Preferably, the difference between the silicon carbide content in the short fiber region III and the silicon carbide content in the long fiber region II and the long fiber region IV is less than 6%.

[0011] Preferably, the thickness of the long fiber region I and the long fiber region V is 0.8 - 3 mm, and the thickness of the long fiber region II and the long fiber region IV is 2 - 20 mm. The thickness of the short fiber region is mainly determined by the overall thickness of the brake disc and is generally 6 - 30 mm.

[0012] The application further provides a preparation method of the carbon fiber reinforced silicon carbide brake disc.

[0013] S1: preparing a coating slurry, the coating slurry comprising a phenolic resin solution with a concentration of 50%, silicon carbide powder and a pore-forming agent, the coating slurry comprising 50-95 vol% of the phenolic resin solution, 0-30 vol% of the silicon carbide powder, and the balance being the pore-forming agent;

[0014] S2: coating the coating slurry onto a plurality of carbon fiber square cloths to obtain long fiber area I fiber cloth and long fiber area V fiber cloth, the content of the silicon carbide powder and the pore-forming agent in the coating slurry for each carbon fiber square cloth decreasing in proportion, and the content of the phenolic resin solution increasing in proportion;

[0015] S3: stacking the long fiber area I fiber cloth and the long fiber area V fiber cloth in the order of decreasing content of the pore-forming agent in the coating slurry, respectively, to obtain a long fiber area I stacking block and a long fiber area V stacking block, respectively;

[0016] S4: drying the long fiber area I stacking block and the long fiber area V stacking block until no weight loss occurs, the drying temperature being 60-70°C, and the volume percentage of the carbon fiber after drying being 30-55% of the total volume;

[0017] S5: coating the coating slurry with the least content of the pore-forming agent in S2 onto carbon fiber square cloths to obtain a plurality of long fiber area II fiber cloths and long fiber area IV fiber cloths, and stacking the long fiber area II fiber cloths and the long fiber area IV fiber cloths, respectively, to obtain a long fiber area II stacking block and a long fiber area IV stacking block;

[0018] S6: drying the long fiber area II stacking block and the long fiber area IV stacking block until no weight loss occurs, the drying temperature being 60-70°C, and the volume percentage of the carbon fiber after drying being 30-55% of the total volume;

[0019] S7: coating the carbon fiber long fiber bundle with a 50% concentration phenolic solution, cutting the carbon fiber long fiber bundle into short fiber bundles with a uniform length of 10-30 mm after drying, and the drying temperature being 60-70°C;

[0020] S8: placing the long fiber area I stacking block, the long fiber area II stacking block, the short fiber bundle, the long fiber area IV stacking block and the long fiber area V stacking block in a mold in the order of long fiber area I stacking block-long fiber area II stacking block-short fiber bundle-long fiber area IV stacking block-long fiber area V stacking block, wherein the long fiber area I stacking block is placed with the long fiber layer having the least content of the pore-forming agent facing downward, and the long fiber area V stacking block is placed with the long fiber layer having the least content of the pore-forming agent facing upward; and then performing pressing and curing to obtain a green body;

[0021] S9: performing carbonization treatment on the green body to obtain a carbonized green body, the carbonization temperature being 900°C, and the holding time being 4-8 h.

[0022] S10: Put the carbonized blank into a boron nitride crucible, put 1.1 times the mass of the blank of pure silicon powder into the boron nitride crucible in advance, then put the boron nitride crucible containing the carbonized blank into a high-temperature vacuum furnace for siliconizing treatment to obtain a siliconized blank, the siliconizing temperature is 1600-1700℃, the holding time is 2-4h, and the furnace pressure is less than 1000Pa;

[0023] S11: Surface grinding and outer contour size processing of the siliconized blank to obtain the carbon fiber reinforced silicon carbide brake disc.

[0024] The pore-forming agent is added to increase the permeability during siliconizing. If there is only phenolic and silicon carbide, there may be occluded pores, and liquid silicon cannot completely penetrate, so some pore-forming agents can be added according to the penetration situation. In addition, the content ratio of silicon carbide and silicon after siliconizing can also be adjusted by the pore-forming agent. If there is only silicon carbide and phenolic, the ratio of silicon carbide and silicon after siliconizing is fixed. The more pore-forming agents, the more silicon remains after siliconizing.

[0025] Preferably, the k value of the carbon fiber square cloth is 3-12k.

[0026] Preferably, the pore-forming agent is pmma plastic particles.

[0027] Preferably, the volume content of the short fiber bundle after drying in S7 is 25-50%.

[0028] Preferably, the pressing condition in S8 is: the pressure is 2-20MPa, the temperature is 150℃, and the time is 2-3h.

[0029] Beneficial effects: the carbon fiber reinforced silicon carbide brake disc provided by the application replaces the commonly used carbon fiber unidirectional cloth and net tire lamination needling method by adopting the way of square cloth lamination. Since the square cloth lamination does not have a needling process, the strength of the long fiber layer can be effectively improved. The core part adopts short fibers as the matrix, and the short fibers and long fibers are combined. The outer layer directly contacts the brake pad, and the stress is more complex. The material mechanical properties of the surface layer of the brake disc are required to be high. The thermal conductivity of the long fiber is higher than that of the short fiber, which is beneficial to the heat dissipation of the surface of the brake disc and avoids the sharp rise of the temperature on the disc surface. The long fiber layer in the long fiber area extends from the surface of the brake disc to the inside in the direction, and the content of silicon carbide in the long fiber layer gradually decreases, so that the content of silicon carbide in the surface layer is high, the brake disc has a good friction coefficient, and the content of silicon carbide gradually decreases with the increase of the number of layers, avoiding the phenomenon that a large amount of residual thermal stress appears due to the sharp change of the content of silicon carbide in the multi-layer material, and effectively ensuring the strength of the material. According to the wear resistance requirement and the brake disc connection strength requirement of the long fiber area I and the long fiber area V, the application puts forward a calculation formula of the content of silicon carbide in each long fiber layer in the long fiber area I and the long fiber area V with the change of the number of layers, which assists in designing the slurry ratio during the preparation process according to the actual brake disc requirement. In addition, the application also provides a preparation method of the carbon fiber reinforced silicon carbide brake disc, which has simple preparation process. Different slurry ratios are brushed on the carbon fiber square cloth, so that the content of silicon carbide in the brake disc gradually changes from outside to inside, and the operation mode is simple and easy to produce. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the carbon fiber reinforced silicon carbide brake disc.

[0031] In the figure: 1-long fiber area I, 2-long fiber area II, 3-short fiber area III, 4-long fiber area IV, 5-long fiber area V. DETAILED DESCRIPTION

[0032] The embodiments described below are only a 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.

[0033] REFERENCE Figure 1The application provides a carbon fiber reinforced silicon carbide brake disc, which comprises a long fiber area I1, a long fiber area II2, a short fiber area III3, a long fiber area IV4 and a long fiber area V5, characterized in that the long fiber area II2 and the long fiber area IV4 are respectively arranged on the two sides of the short fiber area III3 and are symmetrical along the central axis of the short fiber area III3 in the height direction, the long fiber area I1 is arranged on the side of the long fiber area II2 away from the short fiber area III3, the long fiber area V5 is arranged on the side of the long fiber area IV4 away from the short fiber area III3, and the long fiber area I1 and the long fiber area V5 are symmetrical along the central axis of the short fiber area III3 in the height direction; the long fiber area II2 and the long fiber area IV4 are the same in composition, and the long fiber area I1 and the long fiber area V5 are the same in composition; the long fiber area I and the long fiber area V each comprise one layer of long fiber layer, two layers of long fiber layer,..., Nm layers of long fiber layer, the long fiber layer away from the short fiber area III has a silicon carbide content of V SiCf , and the Nm layers of long fiber layer close to the short fiber area III have a silicon carbide content of V SiCb , wherein the silicon carbide content V SiCn of the Nn layers of long fiber layer from the surface one layer of long fiber layer to the Nn layers of long fiber layer decreases with the increase of the layer number, 1 < Nn < Nm, and the content satisfies the following formula:

[0034]

[0035] , wherein V SiCf is 40-70%, V SiCb is 30-50%, Nm is any natural number ranging from 4 to 13, and k is an engineering coefficient, which ranges from 0.8 to 1.2.

[0036] The long fiber area II and the long fiber area IV each comprise M layers of long fiber layer, M is a natural number greater than 1, the composition of each layer of long fiber layer is the same, and each layer of long fiber layer contains 40-65% of carbon, 30-50% of silicon carbide and 3-13% of silicon.

[0037] The short fiber area III is a short fiber layer, the carbon content of the short fiber layer is 35-60%, the silicon carbide content is 35-55%, and the silicon content is 3-13%.

[0038] The difference between the silicon carbide content of the short fiber area III and the silicon carbide content of the long fiber area II and the long fiber area IV is less than 6%.

[0039] The thickness of the long fiber area I and the long fiber area V is 0.8-3 mm, and the thickness of the long fiber area II and the long fiber area IV is 2-20 mm.

[0040] Embodiment 1

[0041] The embodiment provides a carbon fiber reinforced silicon carbide brake disc, and the preparation steps are as follows:

[0042] S1: a coating slurry is prepared, the coating slurry comprises a phenolic resin solution with a concentration of 50%, silicon carbide powder and a pore forming agent, the coating slurry comprises eight layers of coating slurries, the content of the phenolic resin solution (50% concentration) in the first layer of coating slurry is 58%, the content of the silicon carbide powder is 24%, and the content of the pore forming agent is 18%; the content of the silicon carbide powder in the second layer of coating slurry is 2% less than that in the first layer of coating slurry, the content of the pore forming agent is 2% less than that in the first layer of coating slurry, and the content of the phenolic resin solution is 4% more than that in the first layer of coating slurry; the content of the silicon carbide powder in the third layer of coating slurry is 2% less than that in the second layer of coating slurry, the content of the pore forming agent is 2% less than that in the second layer of coating slurry, and the content of the phenolic resin solution is 4% more than that in the second layer of coating slurry; the proportion of each layer of coating slurry is changed in turn until the eighth layer of coating slurry;

[0043] S2: the coating slurry is coated on eight single-bundle carbon fiber square cloths with a k value of 12k respectively to obtain long fiber area I fiber cloth, and the operation is repeated to obtain long fiber area V fiber cloth, the content of the silicon carbide powder and the pore forming agent in the coating slurry used by each carbon fiber square cloth is decreased in proportion, and the content of the phenolic resin solution is increased in proportion;

[0044] S3: after coating, the long fiber area I fiber cloth and the long fiber area V fiber cloth are stacked in the order of decreasing content of the pore forming agent in the coating slurry respectively to obtain a long fiber area I laminated block and a long fiber area V laminated block respectively;

[0045] S4: the long fiber area I laminated block and the long fiber area V laminated block are subjected to drying treatment until no weight loss, the drying temperature is 65°C, and the volume percentage of the carbon fiber after drying is 35% of the total volume;

[0046] S5: the eighth layer of coating slurry (i.e., the coating slurry with the least content of the pore forming agent) is coated on single-bundle carbon fiber square cloths with a k value of 12k to obtain a plurality of long fiber area II fiber cloths and long fiber area IV fiber cloths, and the long fiber area II fiber cloths and the long fiber area IV fiber cloths are stacked respectively to 13 layers to obtain a long fiber area II laminated block and a long fiber area IV laminated block;

[0047] S6: the long fiber area II laminated block and the long fiber area IV laminated block are subjected to drying treatment until no weight loss, the drying temperature is 60°C, and the volume percentage of the carbon fiber after drying is 35% of the total volume;

[0048] S7: the carbon fiber long fiber bundle is coated with a 50% concentration phenolic solution, and after drying, the carbon fiber bundle is cut into short fiber bundles with a uniform length of 15mm; the drying temperature is 60°C, and the volume percentage of the carbon fiber after drying is 30% of the total volume;

[0049] S8: according to the order of long fiber area I laminated block-long fiber area II laminated block-short fiber bundle-long fiber area IV laminated block-long fiber area V laminated block, place into the mold, the thickness of the short fiber bundle after pressing is 10 mm, wherein the long fiber area I laminated block is placed with the long fiber layer with the least pore forming agent downward, and the long fiber area V laminated block is placed with the long fiber layer with the least pore forming agent upward; then perform pressing and curing to obtain a green body, the pressure is 6 MPa, the temperature is 150 DEG C, and the time is 3 h;

[0050] S9: perform carbonization treatment on the green body to obtain a carbonized green body, the carbonization temperature is 900 DEG C, and the holding time is 5 h;

[0051] S10: place the carbonized green body into a boron nitride crucible, pre-place pure silicon powder with a mass of 1.1 times that of the green body in the boron nitride crucible, then place the boron nitride crucible with the carbonized green body into a high-temperature vacuum furnace to perform siliconizing treatment to obtain a siliconized green body, the siliconizing temperature is 1700 DEG C, the holding time is 4 h, and the furnace pressure is less than 1000 Pa;

[0052] S11: perform surface grinding and outer contour size processing on the siliconized green body to obtain the carbon fiber reinforced silicon carbide brake disc.

[0053] Example 2

[0054] The embodiment provides a carbon fiber reinforced silicon carbide brake disc, and the preparation steps are as follows:

[0055] S1: prepare a brushing slurry, the brushing slurry includes a phenolic resin solution with a concentration of 50%, silicon carbide powder and a pore forming agent, the brushing slurry includes 8 layers of brushing slurries, the content of the phenolic resin solution (50% concentration) in the first layer of brushing slurry is 56%, the content of the silicon carbide powder is 22%, and the content of the pore forming agent is 22%; the content of the silicon carbide powder in the second layer of brushing slurry is 2% less than that in the first layer of brushing slurry, the content of the pore forming agent is 2% less than that in the first layer of brushing slurry, and the phenolic resin solution is 4% more than that in the first layer of brushing slurry; the content of the silicon carbide powder in the third layer of brushing slurry is 2% less than that in the second layer of brushing slurry, the content of the pore forming agent is 2% less than that in the second layer of brushing slurry, and the phenolic resin solution is 4% more than that in the second layer of brushing slurry; the proportion of each layer of brushing slurry is changed in turn until the eighth layer of brushing slurry;

[0056] S2: brush the brushing slurry onto 8 single-bundle carbon fiber square grids with a k value of 12k to obtain long fiber area I fiber cloth, repeat the operation to obtain long fiber area V fiber cloth, and the content of the silicon carbide powder and the pore forming agent in the brushing slurry for each carbon fiber square grid is proportionally reduced, and the content of the phenolic resin solution is proportionally increased;

[0057] S3: After brushing, the long fiber area I is stacked with fiber cloth according to the decreasing order of the pore former content in the brushing slurry, and the long fiber area I stacked block is obtained. The long fiber area V after brushing is stacked with fiber cloth according to the decreasing order of the pore former content in the brushing slurry, and the long fiber area V stacked block is obtained.

[0058] S4: The long fiber area I stacked block and the long fiber area V stacked block are subjected to drying treatment until no weight loss, and the drying temperature is 65℃. After drying, the volume percentage of carbon fibers is 35% of the total volume.

[0059] S5: The 8th layer of brushing slurry is brushed on the single bundle of carbon fiber square grid cloth with a k value of 12k to obtain a plurality of long fiber area II fiber cloth and long fiber area IV fiber cloth. The long fiber area II fiber cloth and long fiber area IV fiber cloth are stacked respectively for 13 layers to obtain long fiber area II stacked block and long fiber area IV stacked block.

[0060] S6: The long fiber area II stacked block and the long fiber area IV stacked block are subjected to drying treatment until no weight loss, and the drying temperature is 60℃. After drying, the volume percentage of carbon fibers is 35% of the total volume.

[0061] S7: The carbon fiber long fiber bundle is brushed with a 50% concentration phenolic solution, and after drying, it is cut into short fiber bundles with a uniform length of 15mm. The drying temperature is 60℃, and after drying, the volume percentage of carbon fibers is 30% of the total volume.

[0062] S8: According to the order of long fiber area I stacked block-long fiber area II stacked block-short fiber bundle-long fiber area IV stacked block-long fiber area V stacked block, place it into the mold, and the thickness of the short fiber bundle after pressing is 10mm. Among them, the long fiber area I stacked block is placed with the long fiber layer with the least pore former content facing down, and the long fiber area V stacked block is placed with the long fiber layer with the least pore former content facing up. Then, pressing and curing are carried out to obtain a green body, the pressure is 6MPa, the temperature is 150℃, and the time is 3h.

[0063] S9: The green body is subjected to carbonization treatment to obtain a carbonized body, and the carbonization temperature is 900℃ and the holding time is 5h.

[0064] S10: The carbonized body is placed in a boron nitride crucible, and the boron nitride crucible is pre-filled with pure silicon powder with a mass of 1.1 times that of the green body. Then, the boron nitride crucible containing the carbonized body is placed in a high-temperature vacuum furnace for siliconizing treatment to obtain a siliconized body, and the siliconizing temperature is 1600℃, the holding time is 4h, and the furnace pressure is less than 1000Pa.

[0065] S11: The siliconized body is subjected to surface grinding and outer contour size processing to obtain the carbon fiber reinforced silicon carbide brake disc.

[0066] Example 3

[0067] The embodiment provides a carbon fiber reinforced silicon carbide brake disc, and the preparation steps are as follows:

[0068] S1: a coating slurry is prepared, the coating slurry comprises a phenolic resin solution with a concentration of 50%, silicon carbide powder and a pore forming agent, the coating slurry comprises eight layers of coating slurries, the content of the phenolic resin solution (50% concentration) in the first layer of coating slurry is 58%, the content of the silicon carbide powder is 24%, and the content of the pore forming agent is 18%; the content of the silicon carbide powder in the second layer of coating slurry is 2% less than that in the first layer of coating slurry, the content of the pore forming agent is 2% less than that in the first layer of coating slurry, and the content of the phenolic resin solution is 4% more than that in the first layer of coating slurry; the content of the silicon carbide powder in the third layer of coating slurry is 2% less than that in the second layer of coating slurry, the content of the pore forming agent is 2% less than that in the second layer of coating slurry, and the content of the phenolic resin solution is 4% more than that in the second layer of coating slurry; the proportion of each layer of coating slurry is changed in turn until the eighth layer of coating slurry;

[0069] S2: the coating slurry is coated on eight single-bundle carbon fiber square cloths with a k value of 12k to obtain long fiber area I fiber cloth, and the operation is repeated to obtain long fiber area V fiber cloth, the content of the silicon carbide powder and the pore forming agent in the coating slurry for each carbon fiber square cloth is reduced in proportion, and the content of the phenolic resin solution is increased in proportion;

[0070] S3: after coating, the long fiber area I fiber cloth is stacked in the order of decreasing content of the pore forming agent in the coating slurry to obtain a long fiber area I stacking block, and the long fiber area V fiber cloth after coating is stacked in the order of decreasing content of the pore forming agent in the coating slurry to obtain a long fiber area V stacking block;

[0071] S4: the long fiber area I stacking block and the long fiber area V stacking block are subjected to drying treatment until there is no weight loss, the drying temperature is 65°C, and after drying, the volume proportion of the carbon fiber is 35% of the total volume;

[0072] S5: the eighth layer of coating slurry is coated on single-bundle carbon fiber square cloths with a k value of 12k to obtain a plurality of long fiber area II fiber cloths and long fiber area IV fiber cloths, and the long fiber area II fiber cloths and the long fiber area IV fiber cloths are respectively stacked for 13 layers to obtain a long fiber area II stacking block and a long fiber area IV stacking block;

[0073] S6: the long fiber area II stacking block and the long fiber area IV stacking block are subjected to drying treatment until there is no weight loss, the drying temperature is 60°C, and after drying, the volume proportion of the carbon fiber is 35% of the total volume;

[0074] S7: the carbon fiber long fiber bundle is coated with a 50% concentration phenolic solution, and after drying, the carbon fiber bundle is cut into short fiber bundles with a uniform length of 15mm; the drying temperature is 60°C, and after drying, the volume proportion of the carbon fiber is 35% of the total volume;

[0075] S8: according to the order of long fiber area I laminated block-long fiber area II laminated block-short fiber bundle-long fiber area IV laminated block-long fiber area V laminated block, place into the mold, the thickness of the short fiber bundle after pressing is 10 mm, wherein the long fiber area I laminated block is placed with the long fiber layer with the least pore forming agent downward, and the long fiber area V laminated block is placed with the long fiber layer with the least pore forming agent upward; then perform pressing and curing to obtain a green body, the pressure is 6 MPa, the temperature is 150 DEG C, and the time is 3 h;

[0076] S9: perform carbonization treatment on the green body to obtain a carbonized green body, the carbonization temperature is 900 DEG C, and the holding time is 5 h;

[0077] S10: place the carbonized green body into a boron nitride crucible, pre-place pure silicon powder with a mass of 1.1 times that of the green body in the boron nitride crucible, then place the boron nitride crucible containing the carbonized green body into a high-temperature vacuum furnace to perform siliconizing treatment to obtain a siliconized green body, the siliconizing temperature is 1700 DEG C, the holding time is 4 h, and the furnace pressure is less than 1000 Pa;

[0078] S11: perform surface grinding and outer contour size processing on the siliconized green body to obtain the carbon fiber reinforced silicon carbide brake disc.

[0079] Comparative Example 1

[0080] This comparative example provides a carbon fiber reinforced silicon carbide brake disc, and the preparation steps are as follows:

[0081] S1: prepare a brushing slurry, the brushing slurry includes a phenolic resin solution with a concentration of 50%, silicon carbide powder, and pore forming agent, the content of the phenolic resin solution (50% concentration) in the brushing slurry is 58%, the content of the silicon carbide powder is 24%, and the content of the pore forming agent is 18%;

[0082] S2: apply the brushing slurry to 8 single-bundle carbon fiber square grids with a k value of 12k respectively to obtain long fiber area I fiber cloth and long fiber area V fiber cloth;

[0083] S3: after brushing, stack the long fiber area I fiber cloth in sequence to obtain a long fiber area I laminated block, and stack the long fiber area V fiber cloth in sequence to obtain a long fiber area V laminated block;

[0084] S4: dry the long fiber area I laminated block and the long fiber area V laminated block until there is no more weight loss, the drying temperature is 60 DEG C, and the volume ratio of the carbon fiber after drying is 35% of the total volume;

[0085] S5: Brushing the brushing slurry on the carbon fiber square cloth with a single bundle k value of 12k to obtain a plurality of long fiber area II fiber cloths and long fiber area IV fiber cloths, stacking the long fiber area II fiber cloths and long fiber area IV fiber cloths respectively for 13 layers to obtain a long fiber area II stacking block and a long fiber area IV stacking block;

[0086] S6: The long fiber area II stacking block and the long fiber area IV stacking block are subjected to drying treatment until no weight loss, the drying temperature is 60℃, and the volume percentage of carbon fiber after drying is 35% of the total volume;

[0087] S7: The carbon fiber long fiber bundle is brushed with a 50% concentration phenolic solution, and after drying, it is cut into short fiber bundles with a uniform length of 15mm; the drying temperature is 60℃, and the volume percentage of carbon fiber after drying is 30% of the total volume;

[0088] S8: Place in the mold in the order of long fiber area I stacking block-long fiber area II stacking block-short fiber bundle-long fiber area IV stacking block-long fiber area V stacking block; then press and cure to obtain a green body, the pressure is 6MPa, the temperature is 150℃, the time is 3h, and the thickness of the short fiber bundle after pressing is 10mm;

[0089] S9: The green body is subjected to carbonization treatment to obtain a carbonized green body, the carbonization temperature is 900℃, and the holding time is 5h;

[0090] S10: The carbonized green body is placed in a boron nitride crucible, the boron nitride crucible is pre-filled with pure silicon powder with a mass of 1.1 times that of the green body, and then the boron nitride crucible containing the carbonized green body is placed in a high-temperature vacuum furnace for siliconizing treatment to obtain a siliconized green body, the siliconizing temperature is 1700℃, the holding time is 4h, and the furnace pressure is less than 1000Pa;

[0091] S11: The siliconized green body is subjected to surface grinding and outer contour size processing to obtain the carbon fiber reinforced silicon carbide brake disc.

[0092] Comparative Example 2

[0093] The present embodiment provides a carbon fiber reinforced silicon carbide brake disc, and the preparation steps are as follows:

[0094] S1: Prepare a brushing slurry, the brushing slurry includes a 50% concentration phenolic resin solution, silicon carbide powder and a pore former, the brushing slurry includes 3 layers of brushing slurry, the first layer of brushing slurry contains 58% of phenolic resin solution (50% concentration), 24% of silicon carbide powder and 18% of pore former; the second layer of brushing slurry contains 18% of silicon carbide powder, 11% of pore former and 71% of phenolic resin solution; the third layer of brushing slurry contains 10% of silicon carbide powder, 4% of pore former and 86% of phenolic resin solution;

[0095] S2: The brushing paste is brushed on 3 single-bundle carbon fiber square weaves with a k value of 12k to obtain long fiber area I fiber cloth and long fiber area V fiber cloth;

[0096] S3: After brushing, the long fiber area I fiber cloth and the long fiber area V fiber cloth are respectively stacked according to the order of decreasing pore former content in the brushing paste, to obtain a long fiber area I stacked block and a long fiber area V stacked block;

[0097] S4: The long fiber area I stacked block and the long fiber area V stacked block are subjected to drying treatment until no weight loss, the drying temperature is 60°C, and after drying, the volume percentage of carbon fiber is 35% of the total volume;

[0098] S5: The third layer of brushing paste is brushed on single-bundle carbon fiber square weaves with a k value of 12k to obtain a plurality of long fiber area II fiber cloths and long fiber area IV fiber cloths, the long fiber area II fiber cloths and long fiber area IV fiber cloths are respectively stacked 13 layers to obtain a long fiber area II stacked block and a long fiber area IV stacked block;

[0099] S6: The long fiber area II stacked block and the long fiber area IV stacked block are subjected to drying treatment until no weight loss, the drying temperature is 60°C, and after drying, the volume percentage of carbon fiber is 35% of the total volume;

[0100] S7: The carbon fiber long fiber bundle is brushed with a 50% concentration phenolic solution, after drying, it is cut into short fiber bundles with a uniform length of 15mm; the drying temperature is 60°C, and after drying, the volume percentage of carbon fiber is 30% of the total volume;

[0101] S8: The long fiber area I stacked block, the long fiber area II stacked block, the short fiber bundle, the long fiber area IV stacked block, and the long fiber area V stacked block are placed in the mold in the order of long fiber area I stacked block-long fiber area II stacked block-short fiber bundle-long fiber area IV stacked block-long fiber area V stacked block, the thickness of the short fiber bundle after pressing is 10mm, wherein the long fiber area I stacked block is placed with the long fiber layer containing the least pore former downward, and the long fiber area V stacked block is placed with the long fiber layer containing the least pore former upward; then pressing and curing are performed to obtain a green body, the pressure is 6MPa, the temperature is 150°C, and the time is 3h;

[0102] S9: The green body is subjected to carbonization treatment to obtain a carbonized green body, the carbonization temperature is 900°C, and the holding time is 4h;

[0103] S10: The carbonized green body is placed in a boron nitride crucible, the boron nitride crucible is pre-filled with pure silicon powder with a mass of 1.1 times that of the green body, then the boron nitride crucible containing the carbonized green body is placed in a high-temperature vacuum furnace for siliconizing treatment to obtain a siliconized green body, the siliconizing temperature is 1700°C, the holding time is 4h, and the furnace pressure is less than 1000Pa;

[0104] S11: surface grinding and outer contour size processing are performed on the siliconized blank to obtain the carbon fiber reinforced silicon carbide brake disc.

[0105] The carbon fiber reinforced silicon carbide brake discs prepared in the above examples 1-3 and comparative examples 1-2 are tested. The testing method is as follows:

[0106] The dynamic friction coefficient and wear rate of the carbon ceramic brake disc sample are tested by using MM-1000 friction tester, the effective friction surface of the test ring is D75mm / D55mmx10mm, the specific pressure is 98N / cm 2 , the inertia is 3kgf·cm·s 2 , and the linear speed is 25m / s.

[0107] Whether there is crack in the long fiber area: the test is performed according to the test method specified in QC / T 316. With 0.6g equivalent braking torque, the braking frequency is 20x104times, and the connection hole is checked for cracking every 50,000 times, for a total of 300,000 cycles.

[0108] The test data are shown in Table 1.

[0109] Table 1: Test data of carbon fiber reinforced silicon carbide brake discs of examples 1-3 and comparative examples 1-2 (the outer layer is the first layer, and the layer number gradually increases from outside to inside)

[0110]

[0111] From the above test data, it can be seen that in example 1, the long fiber area I / V area contains 8 layers of fiber layers, and the content of silicon carbide gradually decreases from the surface to the core, effectively relieving the thermal stress caused by the difference in silicon carbide content, and the high content of silicon carbide in the surface layer ensures the friction coefficient; in example 2, the content of silicon carbide in the surface layer is increased by brushing the slurry, and the friction coefficient of the product is improved; in example 3, the volume fraction of short fibers is increased after drying the slurry, and the content of silicon carbide in the short fiber area is reduced, which relieves the difference in expansion coefficient between the long fiber area II / IV and the short fiber area; in comparative example 1, the content of silicon carbide in the long fiber area I / V area does not change gradually, and there is a large amount of residual stress at the interface between the long fiber area I / V area and the long fiber area II / IV, and a large number of cracks appear in the long fiber area after testing; in comparative example 2, the long fiber I / V area has only three layers, and the content of silicon carbide in the three layers changes sharply, which also leads to the generation of a large amount of residual thermal stress, and obvious cracks also appear in the long fiber area during testing.

[0112] 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, therefore, equivalent changes made within the scope of the patent application of the present application still fall within the scope of the present application.

Claims

1. A carbon fiber reinforced silicon carbide brake disc comprising a long fiber zone I, a long fiber zone II, a short fiber zone III, a long fiber zone IV, and a long fiber zone V, characterized in that, The long fiber area II and the long fiber area IV are respectively arranged on both sides of the short fiber area III and are symmetrical along the central axis of the short fiber area III height direction, the long fiber area I is arranged on the side of the long fiber area II away from the short fiber area III, the long fiber area V is arranged on the side of the long fiber area IV away from the short fiber area III, and the long fiber area I and the long fiber area V are symmetrical along the central axis of the short fiber area III height direction; the long fiber area II and the long fiber area IV have the same components, and the long fiber area I and the long fiber area V have the same components; the long fiber area I and the long fiber area V each include 1 layer of long fiber layer, 2 layers of long fiber layer, …, Nm layers of long fiber layer, the 1 layer of long fiber layer is away from the short fiber area III, and the carbon content of the 1 layer of long fiber layer is V SiCf , the Nm layers of long fiber layer are close to the short fiber area III, and the carbon content of the Nm layers of long fiber layer is V SiCb , from the surface 1 layer of long fiber layer to the Nn layer of long fiber layer, the carbon content of the Nn layer of long fiber layer is V SiCn , which decreases with the increase of the layer number, 1 Nn Nm , and the content satisfies the following formula: wherein V SiCf is 40-70%, V SiCb is 30-50%, Nm is any natural number between 4 and 13, and k is an engineering factor with a value range of 0.8-1.

2.

2. The carbon fiber reinforced silicon carbide brake disc of claim 1, wherein, The long fiber area II and the long fiber area IV each comprise M layers of long fiber layers, M being a natural number greater than 1, the components of each layer of long fiber layers being the same, each layer of long fiber layers comprising 40-65% carbon, 30-50 vol% silicon carbide and 3-13 vol% silicon.

3. The carbon fiber reinforced silicon carbide brake disc of claim 1, wherein, The short fiber area III is a short fiber layer, the carbon content of the short fiber layer being 35-60%, the silicon carbide content being 35-55 vol%, and the silicon content being 3-13 vol%.

4. The carbon fiber reinforced silicon carbide brake disc of claim 3, wherein, The difference between the silicon carbide content of the short fiber area III and the silicon carbide content of the long fiber area II and the long fiber area IV is less than 6%.

5. The carbon fiber reinforced silicon carbide brake disc according to any one of claims 1 or 2, characterized in that: The thickness of the long fiber area I and the long fiber area V is 0.8-3 mm, and the thickness of the long fiber area II and the long fiber area IV is 2-20 mm.

6. A method for producing a carbon fiber-reinforced silicon carbide brake disc, for producing a carbon fiber-reinforced silicon carbide brake disc according to any one of claims 1 to 5, characterized in that The preparation method is as follows: S1: prepare a coating slurry, the coating slurry comprising a phenolic resin solution with a concentration of 50%, silicon carbide powder and a pore-forming agent, the coating slurry comprising 50-95 vol% of the phenolic resin solution, 0-30 vol% of the silicon carbide powder, and the balance being the pore-forming agent; S2: coat the coating slurry onto a plurality of carbon fiber square cloths to obtain long fiber area I fiber cloth and long fiber area V fiber cloth, the silicon carbide powder and the pore-forming agent in the coating slurry used for each carbon fiber square cloth decreasing in proportion, and the phenolic resin solution increasing in proportion; S3: stack the long fiber area I fiber cloth and the long fiber area V fiber cloth in order of decreasing pore-forming agent content in the coating slurry, respectively, to obtain a long fiber area I stacked block and a long fiber area V stacked block, respectively; S4: dry the long fiber area I stacked block and the long fiber area V stacked block until there is no more weight loss, the drying temperature being 60-70°C, and the volume percentage of carbon fibers after drying being 30-55% of the total volume; S5: coat the coating slurry with the least pore-forming agent content in S2 onto carbon fiber square cloths to obtain a plurality of long fiber area II fiber cloths and long fiber area IV fiber cloths, and stack the long fiber area II fiber cloths and the long fiber area IV fiber cloths, respectively, to obtain a long fiber area II stacked block and a long fiber area IV stacked block; S6: dry the long fiber area II stacked block and the long fiber area IV stacked block until there is no more weight loss, the drying temperature being 60-70°C, and the volume percentage of carbon fibers after drying being 30-55% of the total volume; S7: coat carbon fiber long fiber bundles with a 50% concentration phenolic solution, cut the carbon fiber long fiber bundles to a uniform length of 10-30 mm after drying; the drying temperature being 60-70°C; S8: place the long fiber area I stacked block, the long fiber area II stacked block, the short fiber bundle, the long fiber area IV stacked block and the long fiber area V stacked block in the mold in the order of long fiber area I stacked block-long fiber area II stacked block-short fiber bundle-long fiber area IV stacked block-long fiber area V stacked block, wherein the long fiber area I stacked block is placed with the long fiber layer having the least pore-forming agent content facing downward, and the long fiber area V stacked block is placed with the long fiber layer having the least pore-forming agent content facing upward; then perform pressing and curing to obtain a green body; S9: perform carbonization treatment on the green body to obtain a carbonized green body, the carbonization temperature being 900°C, and the holding time being 4-8 h; S10: the carbonized blank is put into a boron nitride crucible, pure silicon powder with 1.1 times the mass of the blank is put into the boron nitride crucible in advance, then the boron nitride crucible with the carbonized blank is put into a high-temperature vacuum furnace for siliconizing treatment to obtain a siliconized blank, the siliconizing temperature is 1600-1700℃, the holding time is 2-4h, and the furnace pressure is less than 1000Pa; S11: the siliconized blank is subjected to surface polishing and outer contour size processing to obtain the carbon fiber reinforced silicon carbide brake disc.

7. The method of producing a carbon fiber reinforced silicon carbide brake disc according to claim 6, characterized by, The k value of the carbon fiber square cloth is 3-12k.

8. The method of producing a carbon fiber-reinforced silicon carbide brake disc according to claim 6, characterized by, The pore-forming agent is pmma plastic particles.

9. The method of producing a carbon fiber reinforced silicon carbide brake disc according to claim 6, characterized by, The volume content of the short fiber bundle after drying in S7 is 25-50%.

10. The method of producing a carbon fiber reinforced silicon carbide brake disc according to claim 6, wherein The pressing condition in S8 is that the pressure is 2-20MPa, the temperature is 150℃, and the time is 2-3h.

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