Carbon / carbon brake disc and preparation method thereof

Abstract

The invention provides a carbon / carbon brake disc and a preparation method thereof, the brake disc comprises a structure support disc and a friction disc, and a fiber preform structure and a preparation process are specifically designed according to respective use characteristics of the structure support disc and the friction disc. The structure supporting disc is prepared from a quasi-three-dimensional needling structure carbon fiber preform with the fiber cloth volume mass ratio larger than 80% or a three-dimensional structure carbon fiber preform formed through one-time weaving through a chemical vapor infiltration process in combination with liquid phase impregnation, curing and carbonization processes, and has excellent mechanical performance and heat conduction performance. The friction disc prefabricated body adopts a quasi-three-dimensional needling structure carbon fiber prefabricated body or a pure net tire needling structure carbon fiber prefabricated body with the fiber cloth volume mass ratio being smaller than 40%; the composite material is prepared through a chemical vapor infiltration process and has excellent friction and wear properties. The novel carbon / carbon brake disc is short in preparation period, low in cost and good in quality consistency, only the friction disc needs to be replaced when the service life of the brake disc is up, and maintenance is convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft brakes, and in particular relates to a carbon / carbon brake disc and a preparation method thereof. Background Art

[0002] Carbon / carbon composites (C / C) are materials made of carbon fiber as reinforcement and carbon or graphite as matrix. They have a series of excellent properties such as light weight, high strength, wear resistance, good thermal conductivity and long life, so they are widely used as aviation brake materials. Although the brake materials of military and civilian aircraft at home and abroad are basically made of carbon / carbon composites, the current problems of high cost and poor quality consistency of carbon / carbon brake discs still exist, which greatly affects the economy and reliability of the use of carbon / carbon brake discs.

[0003] The main reasons for the high cost and poor quality consistency of carbon / carbon brake discs are:

[0004] (1) Manufacturing: At present, the domestic preparation of aircraft carbon / carbon brake discs mainly adopts quasi-three-dimensional needle-punched integral felt, which is densified by chemical vapor infiltration (CVI) process to obtain a rough layer structure "deposited carbon" with excellent friction and wear performance. However, the thickness of the carbon / carbon brake disc preform is about (30-50) mm, and the CVI process is prone to bottleneck effect during the densification process. It is necessary to repeatedly perform heat treatment and mechanical processing to open the pores, resulting in a long preparation cycle and complex process. In recent years, everyone has improved the preparation efficiency of carbon / carbon brake discs and reduced the manufacturing cost by means of preform structure design (see CN 113502606A), process optimization (see CN 111454075 B), and tooling optimization (see CN 11348931 A), so that the quality consistency of carbon / carbon brake discs has been effectively improved, and the production cycle and manufacturing cost have also been greatly reduced. However, the CVI densification process of carbon / carbon brake discs has a long cycle and high cost compared to the liquid phase immersion carbonization process. At the same time, the carbon / carbon brake discs have the "hollow" problem of high external density and low internal density in the thickness direction.

[0005] (2) Usage and maintenance: Carbon / carbon brake discs are important consumable parts of aircraft braking systems. They are subject to wear during the braking process and wear out after a period of service. Due to limitations in mechanical properties, size structure, and safety of use, the designed wear amount in the thickness direction of aircraft carbon / carbon brake discs that have reached the end of their service life is only 10%-30% of the total thickness of the carbon brake disc. Aircraft carbon brake discs are expensive, so the cost of directly discarding them after they have reached the end of their service life is high. In order to reduce the cost of using aircraft carbon / carbon brake discs and increase the utilization rate of materials, two or three carbon / carbon brake discs that have reached the end of their service life are generally combined into a new brake disc through mechanical processing, anti-oxidation treatment, bonding and other processes for reuse. However, this replacement method, commonly known as "two-in-one" or "three-in-one", requires reprocessing of the brake discs that have reached the end of their service life. The repair and replacement methods have the disadvantages of long repair cycles and insufficient mechanical and friction properties.

[0006] Therefore, it is necessary to design and develop the carbon / carbon brake disc structure and process methods to address the problems of high use cost and poor quality consistency of carbon / carbon brake discs, so as to reduce the use cost of carbon / carbon brake discs and improve the performance stability of carbon / carbon brake discs. Summary of the invention

[0007] The purpose of the present invention is to solve the problems of long manufacturing cycle, poor quality consistency and high maintenance cost of existing carbon / carbon brake discs, and to provide a carbon / carbon brake disc and a preparation method thereof.

[0008] To achieve the above purpose, the technical solution provided by the present invention is:

[0009] A carbon / carbon brake disc, which is special in that it comprises two friction discs, a connecting assembly and a structural support disc, wherein the structural support disc is coaxially arranged between the two friction discs, and the edges of the structural support disc and the friction disc are fixed by the connecting assembly;

[0010] The structural support disc has the same shape and radial dimensions as the friction disc, and the axial dimension of the friction disc is smaller than the axial dimension of the structural support disc;

[0011] The structural support plate is obtained by sequentially subjecting a structural support plate preform to densification treatment, high temperature heat treatment and fine processing; the structural support plate preform is a quasi-three-dimensional needle-punched carbon fiber preform obtained by needle-punching a carbon fiber mesh and a carbon fiber cloth, with a carbon fiber cloth volume-to-mass ratio greater than 80%, and a density of 0.6-1.0 g / cm 3 ; or a three-dimensional carbon fiber preform formed by one-time weaving of carbon fibers, with a density of 0.7 to 1.2 g / cm 3 ;

[0012] The friction disc is obtained by sequentially subjecting a friction disc preform to densification treatment, high temperature heat treatment and fine processing; the friction disc preform is a quasi-three-dimensional needle-punched carbon fiber preform obtained by needle-punching a carbon fiber web and a carbon fiber cloth, with a fiber cloth volume-to-mass ratio of less than 40%, and a density of 0.3-0.6 g / cm 3 ; or pure carbon fiber mesh needle-punched structure, density is 0.15 ~ 0.25g / cm 3 .

[0013] Furthermore, the edges of the friction disk and the structural support disk are evenly distributed around the circumference with a plurality of U-shaped grooves opening outward; the connecting assembly includes a steel clip, a clip and a rivet, and the steel clip is bonded and fixed in the U-shaped groove; the outer surfaces of the two friction disks are provided with a clip, and the friction disk and the structural support disk are fixed axially by rivets.

[0014] Furthermore, the open end of the side wall of the steel clip is symmetrically provided with lugs extending outward, and the lugs can respectively press the surfaces of the two friction plates. The ends of the lugs and the ends of the clip are provided with matching L-shaped notch structures. Furthermore, the connection assembly is made of high-temperature metal material.

[0015] The method for preparing the carbon / carbon brake disc is characterized by comprising the following steps:

[0016] Step 1, preparing a structural support plate;

[0017] Step 1.1, prepare a density of 0.60g / cm 3 ~1.2g / cm 3 A structural support plate preform;

[0018] The structural support plate preform is prepared by the following method:

[0019] The carbon fiber mesh is alternately layered with single or multi-layer carbon fiber cloth, and the Z-direction fiber is introduced by needle punching process to obtain a density of 0.6-1.0g / cm 3 Quasi-three-dimensional needle-punched carbon fiber preform;

[0020] Or the carbon fiber is woven once to form a density of 0.7 to 1.2 g / cm 3 Three-dimensional carbon fiber preform;

[0021] Step 1.2, densification treatment:

[0022] Chemical vapor infiltration treatment: Place the preform of the structural support plate into a chemical vapor infiltration device for chemical vapor infiltration treatment to obtain a density of 1.4-1.6 g / cm 3 A structural support disc blank;

[0023] Liquid phase impregnation treatment: the structural support disc blank is placed in a liquid phase impregnation device for impregnation and curing treatment. After curing, the structural support disc blank is subjected to carbonization and cracking treatment by a carbonization device. The impregnation-curing-carbonization and cracking treatment is repeated 2-5 times to obtain a structure containing resin carbon / asphalt carbon. The density of the structure containing resin carbon / asphalt carbon is 1.8-2.2 g / cm 3 ;

[0024] Step 1.3, high temperature heat treatment: subjecting the structure containing resin carbon / asphalt carbon to high temperature heat treatment to adjust the carbon phase structure inside the body; the high temperature heat treatment temperature is 1800° C. to 2500° C., and the holding time is 1 to 4 hours;

[0025] Step 1.4, mechanically processing to obtain a structural support disk, and performing an anti-oxidation coating treatment on the structural support disk;

[0026] Step 2, preparing a friction disc;

[0027] Step 2.1, prepare a density of 0.15-0.6 g / cm 3 A friction disc preform;

[0028] The friction disc preform is prepared in the following manner:

[0029] Single or multi-layer carbon fiber webs are alternately layered with single-layer carbon fiber cloths, and Z-phase fibers are introduced by needle punching to obtain a density of 0.3-0.6 g / cm 3 Quasi-three-dimensional needle-punched carbon fiber preform;

[0030] Or the carbon fiber mesh layer is needle-punched to obtain a density of 0.15-0.25g / cm 3 Pure carbon fiber mesh tire needle-punched structure;

[0031] Step 2.2, subjecting the friction disc preform prepared in step 2.1 to chemical vapor infiltration densification treatment to obtain a density of 1.7 g / cm 3 ~1.8g / cm 3 A friction disc blank;

[0032] Step 2.3, subjecting the friction disc blank obtained in step 2.2 to a high temperature heat treatment at a temperature of 1800° C. to 2500° C. to adjust the carbon phase structure inside the blank, and the high temperature heat treatment holding time is 1 to 4 hours;

[0033] Step 2.4, mechanically processing a friction disc, and performing an anti-oxidation coating treatment on the friction disc;

[0034] Step 3, coaxially placing the obtained structural support disc between two friction discs, and fixing the edges of the friction discs and the structural support disc by a plurality of connecting components to obtain a carbon / carbon brake disc.

[0035] Furthermore, in step 1.2, the specific process of placing the structural support plate preform into a chemical vapor infiltration device for densification treatment is as follows:

[0036] The chemical vapor infiltration device is evacuated until the pressure in the cavity is less than 0.5 kPa. After maintaining the pressure for 2 to 6 hours, the pressure in the cavity is no more than 1.5 kPa.

[0037] After the pressure is maintained, the temperature in the chemical vapor infiltration device is raised to 900℃~1100℃, and then a mixture of natural gas and propane gas is introduced at a speed of 0.7m / s~2m / s for 100~200 hours of densification treatment to obtain a density of 1.2g / cm 3 ~1.5g / cm 3 A structural support disc blank;

[0038] The volume ratio of natural gas to propane gas in the mixed gas is 75-88:12-25.

[0039] Furthermore, in the step 1.2, the preform of the structural support plate subjected to the chemical vapor infiltration densification treatment is placed in a liquid phase impregnation device, and the structural support plate blank is impregnated and cured, and the carbonization and cracking treatment is performed after curing. The process is as follows:

[0040] Impregnation treatment: evacuate the liquid phase impregnation device to a pressure less than 0.5 kPa, absorb the resin / asphalt impregnating agent into the cavity of the liquid phase impregnation device, and after impregnation for 0.5 to 1 hour, introduce inert gas into the cavity of the liquid phase impregnation device, adjust the pressure in the cavity to 3 MPa to 5 MPa, and continue impregnation for 1 to 2 hours;

[0041] Curing treatment: the structural support plate blank is cured under normal pressure, the curing temperature is 100°C to 260°C, and the curing time is 3 to 5 hours;

[0042] Carbonization and cracking treatment: the solidified green body is placed in a carbonization device for carbonization and cracking treatment; the carbonization and cracking temperature is 800°C to 1200°C, the pressure in the carbonization device cavity is less than 3KPa, and the insulation time is 2 to 5 hours.

[0043] Furthermore, in step 1.3, the process of high temperature heat treatment is as follows:

[0044] placing the structural support disc blank in a high temperature heat treatment device;

[0045] The inside of the high-temperature heat treatment device is evacuated until the pressure in the chamber is less than 0.5 kPa, and the pressure does not exceed 1.5 kPa after maintaining the pressure for 8 to 12 hours; the temperature in the high-temperature heat treatment device is increased to 1800°C to 2500°C, and maintained for 1 to 4 hours.

[0046] Furthermore, the process of performing chemical vapor infiltration densification treatment in step 2.2 is as follows: placing the friction disc preform into a chemical vapor infiltration device, adjusting the pressure in the cavity of the chemical vapor infiltration device to less than 0.5 kPa by vacuuming, and maintaining the pressure for 4 hours until the pressure in the cavity is no more than 1.5 kPa;

[0047] After maintaining the pressure, the temperature in the chemical vapor infiltration device is raised to 900℃~1100℃, and then a mixture of natural gas and propane gas is introduced at a speed of 0.7m / s~2m / s for 300~600 hours of densification treatment to obtain a density of 1.7g / cm 3 ~1.8g / cm 3 A friction disc blank;

[0048] The volume ratio of natural gas to propane gas in the mixed gas is 75-88:12-25.

[0049] Furthermore, the process of high temperature treatment in step 2.3 is as follows:

[0050] Placing the friction disc blank obtained in step 2.2 in a high temperature heat treatment device;

[0051] The inside of the high-temperature heat treatment device is evacuated until the pressure in the chamber is less than 0.5 kPa, and the pressure does not exceed 1.5 kPa after maintaining the pressure for 8 to 12 hours; the temperature in the high-temperature heat treatment device is increased to 1800°C to 2500°C, and maintained for 1 to 4 hours.

[0052] The advantages of the present invention are:

[0053] 1. The present invention separates the carbon / carbon brake disc into two friction discs with friction function and a structural support disc coaxially fixed between the friction discs and having a structural support function. According to the different performance requirements of the friction disc and the structural support disc, different and special processing processes are adopted to prepare them. Compared with the traditional integrated carbon / carbon brake disc, the performance advantages of carbon / carbon composite materials made by different processes can be better exerted.

[0054] 2. The thickness of the friction disc and the structural support disc in the present invention is reduced by more than half compared with the traditional brake disc. Since the structural support disc does not need to participate in friction, a liquid phase impregnation process with a shorter cycle is adopted. The friction disc mainly participates in friction, so a pure mesh structure or a quasi-three-dimensional needle-punched structure with a lower density is adopted. The internal pores are large, the deposition speed is high, and the preparation cycle is short. The production cycle is shortened by 1 / 2 compared with the traditional method, and the corresponding manufacturing cost is reduced by 1 / 4.

[0055] 3. After the carbon / carbon brake disc of the present invention reaches the end of its service life, the structural support disc can continue to be used, and only the friction disc needs to be replaced. The replacement process is more economical, convenient and quick. Compared with the traditional overall replacement, it can save 1 / 3-1 / 4 of the replacement cost. Compared with the current "two-in-one" or "three-in-one" repair, although the use cost is equivalent, the replacement cycle can be shortened by more than 80%, reducing the use and maintenance cost of the carbon / carbon brake disc.

[0056] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0058] Figure 1 It is a schematic diagram of the structure of the carbon / carbon brake disc of the present invention;

[0059] Figure 2 yes Figure 1 A partial enlarged view of the middle A;

[0060] Figure 3 It is a schematic diagram of the structure and appearance of the friction disc in the present invention;

[0061] Figure 4 It is a schematic diagram of the structural appearance of the structural support plate in the present invention.

[0062] Explanation of the reference numerals: 1 - friction disc, 2 - structural support disc, 3 - steel clip, 4 - clip, 5 - rivet. DETAILED DESCRIPTION

[0063] Embodiments of the present invention are described in detail below. The embodiments are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0064] A carbon / carbon brake disc comprises two friction discs 1, a connecting assembly and a structural support disc 2. The structural support disc 2 is coaxially fixed between the two friction discs through a plurality of connecting assemblies. The structural support disc has the same outer shape and radial dimensions as the friction disc, and the axial dimension of the friction disc is smaller than the axial dimension of the structural support disc.

[0065] The structural support plate is obtained by sequentially subjecting a structural support plate preform to densification treatment, high temperature heat treatment and fine processing; the structural support plate preform is a quasi-three-dimensional needle-punched carbon fiber preform obtained by needle-punching a carbon fiber mesh and a carbon fiber cloth, with a carbon fiber cloth volume-to-mass ratio greater than 80%, and a density of 0.6-1.0 g / cm 3; or a three-dimensional carbon fiber preform formed by one-time weaving of carbon fibers, with a density of 0.7 to 1.2 g / cm 3 .

[0066] The friction disc is obtained by sequentially subjecting a friction disc preform to densification treatment, high temperature heat treatment and fine processing; the friction disc preform is a quasi-three-dimensional needle-punched carbon fiber preform obtained by needle-punching a carbon fiber web and a carbon fiber cloth, with a fiber cloth volume-to-mass ratio of less than 40%, and a density of 0.3-0.6 g / cm 3 ; or pure carbon fiber mesh needle-punched structure, density is 0.15 ~ 0.25g / cm 3 .

[0067] The carbon fiber cloth is a plain cloth, a satin cloth, a twill cloth or a non-weft unidirectional cloth made of carbon fiber.

[0068] The edges of the friction disk 1 and the structural support disk 2 are uniformly distributed around the circumference with a number of U-shaped grooves opening outward; the connection assembly includes a steel clip 3, a clip 4 and a rivet 5, and the steel clip 3 is bonded and fixed in the U-shaped groove. Clips are provided on the outer surfaces of the two friction disks, and the friction disks and the structural support disks are fixed axially by rivets 5. The steel clip 3 is an integral U-plate component, and the open end of the side wall of the steel clip 3 is symmetrically provided with lugs extending outward, and the lugs can respectively press the surfaces of the two friction disks. The ends of the lugs and the ends of the clips are provided with matching L-shaped notch structures. The connection assembly is made of high-temperature metal material.

[0069] The preparation process of the novel carbon / carbon brake disc of the present invention is described below in conjunction with specific embodiments.

[0070] Example 1

[0071] Step 1: Prepare a structural support plate.

[0072] The preform of the structural support plate adopts a quasi-three-dimensional needle-punched structure with one layer of carbon fiber mesh and two layers of carbon fiber non-weft cloth alternately laid. The adjacent non-weft cloth fibers are staggered at 0° and 90°. The Z-phase fiber is introduced by needle-punching process to obtain a quasi-three-dimensional carbon fiber preform. The density of the carbon fiber preform is 0.65g / cm 3 .

[0073] Chemical vapor infiltration treatment: The prepared structural support plate preform is placed in a chemical vapor infiltration device for densification treatment. The specific process is: evacuate the cavity until the pressure is less than 0.5 kPa, maintain the pressure for 4 hours until the pressure does not exceed 1.5 kPa, turn on the power and heat to 1050 ° C, and introduce carbon source gas at a speed of 1 m / s. The carbon source gas is a mixture of natural gas and propane gas, and the volume ratio of natural gas to propane gas is 88:12; perform a 200-hour densification treatment to obtain a density of 1.4-1.6 g / cm 3The carbon / carbon structure supports the disc blank.

[0074] Liquid phase impregnation treatment: First, the carbon / carbon structural support disk blank is placed in a liquid phase impregnation device and vacuumed to a pressure less than 0.5 KPa. Then, the epoxy resin is sucked into the impregnation chamber and impregnated for 1 hour. Nitrogen is introduced into the impregnation chamber to a pressure of 3 MPa and impregnated for 1.5 hours.

[0075] Then, the impregnated carbon / carbon structure support disc blank was cured at 230°C for 2.5 hours under normal pressure. The cured carbon / carbon structure support disc blank was placed in a carbonization device, vacuumed to a pressure of 1 KPa, and heated to 960°C for 3.5 hours of carbonization treatment.

[0076] Repeat the impregnation-curing-carbonization process 4 times to obtain a density of 2.00±0.05g / cm 3 The carbon / carbon structure supports the disc blank.

[0077] High temperature heat treatment: The densified carbon / carbon structure support disk blank is placed in a high temperature heat treatment furnace at a pressure of 1.5 kPa and a temperature of 2000°C for 4 hours of high temperature heat treatment.

[0078] Mechanical processing: the carbon / carbon structural support disc blank that has completed high-temperature heat treatment is mechanically processed according to the drawings, and at the same time, the whole is subjected to anti-oxidation treatment to obtain the carbon / carbon structural support disc.

[0079] Step 2: Prepare the friction disc.

[0080] Preparation of friction disc preform: The friction disc preform is a pure mesh structure carbon fiber preform obtained by needle punching multiple layers of carbon fiber mesh. The density of the carbon fiber preform is 0.23g / cm 3 .

[0081] Chemical vapor infiltration densification treatment: The prepared friction disc preform is placed in a chemical vapor infiltration device for densification treatment. The specific characteristics are that the pressure in the cavity is evacuated to less than 0.5 kPa, and the pressure does not exceed 1.5 kPa after 4 hours of pressure maintenance. The power is turned on and the temperature is raised to 1050 ° C. A mixed gas of natural gas and propane gas is introduced at a speed of 1.3 m / s. The volume ratio of natural gas to propane gas is 75:25. The densification treatment is carried out for 350 hours to obtain a density of 1.80±0.05 g / cm 3 Carbon / carbon friction disc blank.

[0082] High temperature heat treatment: The densified carbon / carbon structure support disk blank is placed in a high temperature heat treatment furnace at a pressure of 1.5 kPa and a temperature of 2400°C for 4 hours of high temperature heat treatment.

[0083] Machining: The carbon / carbon friction disc blank that has completed high-temperature heat treatment is machined according to the drawing, and the non-friction surface is subjected to anti-oxidation treatment to obtain a carbon / carbon friction disc.

[0084] Step 3: Carbon / carbon brake disc connection process:

[0085] According to the structural design requirements, the prepared structural support disc 2 is coaxially placed between the two friction discs 1 to form a combination, and the structural support disc and the edge of the friction disc are fixedly connected by an auxiliary tooling through a connecting assembly. Before fixing, the structural support disc and the friction disc can be pre-treated on the contact surface by bonding, thermal curing, etc. according to performance requirements.

[0086] Example 2

[0087] Step 1: Prepare a structural support plate.

[0088] The preform of the structural support plate is made of a layer of carbon fiber mesh and two layers of carbon fiber plain cloth alternately laid, and the Z-phase fiber is introduced by needle punching process to obtain a quasi-three-dimensional carbon fiber preform. The density of the carbon fiber preform is 0.65g / cm 3 .

[0089] Chemical vapor infiltration treatment: The prepared structural support plate preform is placed in a chemical vapor infiltration device for densification treatment. The specific process is: evacuate the cavity until the pressure is less than 0.5 kPa, maintain the pressure for 4 hours and the pressure does not exceed 1.5 kPa, turn on the power and heat to 1050 ° C, and introduce a mixture of natural gas and propane gas at a speed of 1 m / s. The volume ratio of natural gas to propane gas is 85:15. Perform a densification treatment for 200 hours to obtain a density of 1.4-1.6 g / cm 3 The carbon / carbon structure supports the disc blank.

[0090] Liquid phase impregnation treatment: The carbon / carbon structural support disk blank is placed in a liquid phase impregnation device, and the vacuum pressure is reduced to less than 0.5KPa. Then, the epoxy resin is sucked into the impregnation chamber and impregnated for 1 hour. Then, nitrogen is introduced into the impregnation chamber to make the pressure in the chamber 3MPa. The impregnation is carried out for 1.5 hours at a temperature of 230°C and cured for 2.5 hours. The cured carbon / carbon structural support disk blank is placed in a carbonization device, and the vacuum pressure is reduced to 1KPa. The temperature is raised to 960°C and carbonized for 3.5 hours. The impregnation-curing-carbonization treatment is repeated 4 times to obtain a density of 2.00±0.05g / cm 3 The carbon / carbon structure supports the disc blank.

[0091] High temperature heat treatment: The densified carbon / carbon structure support disk blank is placed in a high temperature heat treatment furnace at a pressure of 1.5 kPa and a temperature of 2000°C for 4 hours of high temperature heat treatment.

[0092] Mechanical processing: the carbon / carbon structural support disc blank that has completed high-temperature heat treatment is mechanically processed according to the drawings, and at the same time, the whole is subjected to anti-oxidation treatment to obtain the carbon / carbon structural support disc.

[0093] Step 2: Friction disc preparation.

[0094] Preparation of friction disc preform: two layers of carbon fiber mesh and one layer of carbon fiber non-woven fabric are alternately laid, and the adjacent non-woven fabric fibers are at 0° and 90°. The Z-phase fiber is introduced by needle punching process to obtain a quasi-three-dimensional carbon fiber preform. The density of the carbon fiber preform is 0.48g / cm 3 .

[0095] Chemical vapor infiltration densification treatment: The prepared friction disc preform is placed in a chemical vapor infiltration device for densification treatment, which is characterized in that the pressure in the cavity is evacuated to less than 0.5 kPa, and the pressure does not exceed 1.5 kPa after 4 hours of pressure maintenance. The power is turned on and the temperature is raised to 1050°C. A mixed gas of natural gas and propane gas is introduced at a speed of 1 m / s, and the volume ratio of natural gas to propane gas is 80:20. The densification treatment is carried out for 400 hours to obtain a density of 1.75±0.05 g / cm 3 Carbon / carbon friction disc blank.

[0096] High temperature heat treatment: The densified carbon / carbon structure support disk blank is placed in a high temperature heat treatment furnace at a pressure of 1.5 kPa and a temperature of 2400°C for 4 hours of high temperature heat treatment.

[0097] The carbon / carbon friction disc blank that has undergone high-temperature heat treatment is machined according to structural design requirements, and the non-friction surface is subjected to anti-oxidation treatment to obtain a carbon / carbon friction disc.

[0098] Step 3: Carbon / carbon brake disc connection process:

[0099] According to the structural design requirements, the structural support disc 2 is coaxially placed between the two friction discs 1 to form a combination, and the structural support disc and the edge of the friction disc are fixedly connected by auxiliary tooling through a connecting assembly. Before fixing, the structural support disc and the friction disc can be pre-treated on the contact surface by bonding, thermal curing, etc. according to performance requirements.

[0100] Example 3

[0101] Step 1: Structural support plate preparation.

[0102] The structural support plate preform is a three-dimensional five-directional carbon fiber preform formed by one-time weaving of carbon fiber. The density of the carbon fiber preform is 0.85g / cm 3 .

[0103] Chemical vapor infiltration treatment: The prepared structural support plate preform is placed in a chemical vapor infiltration device for densification treatment. The specific characteristics are that the pressure in the cavity is evacuated to less than 0.5 kPa, and the pressure does not exceed 1.5 kPa after 4 hours of pressure maintenance. The power is turned on and the temperature is raised to 1050 ° C. A mixed gas of natural gas and propane gas is introduced at a speed of 0.8 m / s. The volume ratio of natural gas to propane gas is 88:12. The densification treatment is carried out for 200 hours to obtain a density of 1.4-1.6 g / cm 3 The carbon / carbon structure supports the disc blank.

[0104] Liquid phase impregnation treatment: The carbon / carbon structural support disc blank is placed in a liquid phase impregnation device, and the vacuum pressure is reduced to less than 0.5KPa. Then, the asphalt is sucked into the impregnation chamber and impregnated for 1 hour. Then, nitrogen is introduced into the impregnation chamber to make the pressure in the chamber reach 3MPa, and the impregnation is continued for 2 hours. The impregnated carbon / carbon structural support disc blank is cured at normal pressure and a temperature of 100°C for 2 hours. The cured carbon / carbon structural support disc blank is placed in a carbonization device, and the vacuum pressure is reduced to 1kPa. The temperature is raised to 850°C and carbonized for 2 hours. The impregnation-curing-carbonization treatment is repeated 3 times to obtain a density of 2.00±0.05g / cm 3 The carbon / carbon structure supports the disc blank.

[0105] High temperature heat treatment: The densified carbon / carbon structural support disc blank is placed in a high temperature heat treatment furnace at a pressure of 1.5 kPa and a temperature of 2000°C for 4 hours of high temperature heat treatment. The carbon / carbon structural support disc blank that has completed high temperature heat treatment is machined according to the drawings, and the whole is subjected to anti-oxidation treatment to obtain a carbon / carbon structural support disc.

[0106] Step 2: Friction disc preparation.

[0107] The friction disc preform is a carbon fiber preform obtained by needle punching a pure carbon fiber mesh layer. The density of the carbon fiber preform is 0.22g / cm 3 .

[0108] Chemical vapor infiltration densification treatment: The prepared friction disc preform is placed in a chemical vapor infiltration device for densification treatment. The specific process is: evacuate the cavity until the pressure is less than 0.5 kPa, maintain the pressure for 4 hours until the pressure does not exceed 1.5 kPa, turn on the power and heat to 1050 ° C, and introduce a mixture of natural gas and propane gas at a speed of 1.3 m / s. The volume ratio of natural gas to propane gas is 75:25. Perform a densification treatment for 350 hours to obtain a density of 1.75 ± 0.05 g / cm 3 Carbon / carbon friction disc blank.

[0109] High temperature heat treatment: The densified carbon / carbon structural support disc blank is placed in a high temperature heat treatment furnace at a pressure of 1.5 kPa and a temperature of 2300°C for 1.5 hours of high temperature heat treatment. The carbon / carbon friction disc blank that has completed high temperature heat treatment is machined according to the structural design, and the non-friction surface is subjected to anti-oxidation treatment to obtain a carbon / carbon friction disc.

[0110] Step 3: Carbon / carbon brake disc connection process:

[0111] According to the structural design requirements, the structural support disc 2 is coaxially placed between the two friction discs 1 to form a combination, and the structural support disc and the edge of the friction disc are fixedly connected by auxiliary tooling through a connecting assembly. Before fixing, the structural support disc and the friction disc can be pre-treated on the contact surface by bonding, thermal curing, etc. according to performance requirements.

[0112] Example 4

[0113] Step 1: Prepare the structural support disk.

[0114] Preparation of structural support plate preform: A three-dimensional five-directional preform is obtained by one-time weaving of carbon fiber. The density of the carbon fiber preform is 0.85g / cm 3 .

[0115] Chemical vapor infiltration treatment: The prepared structural support plate preform is placed in a chemical vapor infiltration device for densification treatment. The specific characteristics are that the pressure in the cavity is evacuated to less than 0.5 kPa, and the pressure does not exceed 1.5 kPa after 4 hours of pressure maintenance. The power is turned on and the temperature is raised to 1050 ° C. A mixed gas of natural gas and propane gas is introduced at a speed of 0.8 m / s. The volume ratio of natural gas to propane gas is 88:12. The densification treatment is carried out for 200 hours to obtain a density of 1.4-1.6 g / cm 3 The carbon / carbon structure supports the disc blank.

[0116] Liquid phase impregnation treatment: Place the carbon / carbon structural support disc blank into a liquid phase impregnation device, evacuate the pressure to less than 0.5KPa, then absorb the asphalt into the impregnation chamber and immerse for 1 hour, then introduce nitrogen into the impregnation chamber to make the pressure in the chamber reach 3MPa, and immerse for 2 hours. The impregnated carbon / carbon structural support disc blank is cured at normal pressure and 100°C for 2 hours. The cured carbon / carbon structural support disc blank is placed in a carbonization device, evacuated to a pressure of 1kPa, heated to 850°C, and carbonized for 2 hours. The impregnation-curing-carbonization treatment is repeated 3 times to obtain a density of 2.00±0.05g / cm 3 The carbon / carbon structure supports the disc blank.

[0117] High temperature heat treatment: The densified carbon / carbon structural support disc blank is placed in a high temperature heat treatment furnace at a pressure of 1.5 kPa and a temperature of 2000°C for 4 hours of high temperature heat treatment. The carbon / carbon structural support disc blank that has completed high temperature heat treatment is machined according to the drawings, and the whole is subjected to anti-oxidation treatment to obtain a carbon / carbon structural support disc.

[0118] Step 2: Friction disc preparation.

[0119] The friction disc is made of two layers of carbon fiber mesh and one layer of non-woven fabric alternately laid, the adjacent non-woven fabric fibers are 0° and 90°, and the Z-phase fiber is introduced by needle punching process to obtain a quasi-three-dimensional carbon fiber preform. The density of the carbon fiber preform is 0.45g / cm 3 .

[0120] Chemical vapor infiltration densification treatment: The prepared friction disc preform is placed in a chemical vapor infiltration device for densification treatment. The specific characteristics are that the pressure in the cavity is evacuated to less than 0.5 kPa, and the pressure does not exceed 1.5 kPa after 4 hours of pressure maintenance. The power is turned on and the temperature is raised to 1050 ° C. A mixed gas of natural gas and propane gas is introduced at a speed of 1 m / s. The volume ratio of natural gas to propane gas is 80:20. The densification treatment is carried out for 400 hours to obtain a density of 1.80±0.05 g / cm 3 Carbon / carbon friction disc blank.

[0121] High temperature heat treatment: The densified carbon / carbon structure support disk blank is placed in a high temperature heat treatment furnace at a pressure of 1.5 kPa and a temperature of 2100°C for 4 hours of high temperature heat treatment.

[0122] The carbon / carbon friction disc blank that has undergone high-temperature heat treatment is machined according to the structural design, and the non-friction surface is subjected to anti-oxidation treatment to obtain a carbon / carbon friction disc.

[0123] Step 3: Carbon / carbon brake disc connection process:

[0124] According to the structural design requirements, the structural support disc 2 is coaxially placed between the two friction discs 1 to form a combination, and the structural support disc and the edge of the friction disc are fixedly connected by auxiliary tooling through a connecting assembly. Before fixing, the structural support disc and the friction disc can be pre-treated on the contact surface by bonding, thermal curing, etc. according to performance requirements.

[0125] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be included in the protection scope of the present invention.

Claims

1. A carbon / carbon brake disc, characterized in that: It comprises two friction discs, a connecting assembly and a structural support disc, wherein the structural support disc is coaxially arranged between the two friction discs, and the edges of the structural support disc and the friction disc are fixed by the connecting assembly; The structural support disc has the same shape and radial dimensions as the friction disc, and the axial dimension of the friction disc is smaller than the axial dimension of the structural support disc; The structural support plate is obtained by sequentially subjecting a structural support plate preform to densification treatment, high temperature heat treatment and fine processing; the structural support plate preform is a quasi-three-dimensional needle-punched carbon fiber preform obtained by needle-punching a carbon fiber mesh and a carbon fiber cloth, with a carbon fiber cloth volume-to-mass ratio greater than 80%, and a density of 0.6-1.0 g / cm 3 ; or a three-dimensional carbon fiber preform formed by one-time weaving of carbon fibers, with a density of 0.7 to 1.2 g / cm 3 ; The friction disc is obtained by sequentially subjecting a friction disc preform to densification treatment, high temperature heat treatment and fine processing; the friction disc preform is a quasi-three-dimensional needle-punched carbon fiber preform obtained by needle-punching a carbon fiber web and a carbon fiber cloth, with a fiber cloth volume-to-mass ratio of less than 40%, and a density of 0.3-0.6 g / cm 3 ; or pure carbon fiber mesh needle-punched structure, density is 0.15 ~ 0.25g / cm 3 .

2. The carbon / carbon brake disc according to claim 1, characterized in that: The edges of the friction disk and the structural support disk are uniformly distributed around the circumference with a plurality of U-shaped grooves opening outward; The connecting assembly comprises a steel clip, a clip and a rivet, and the steel clip is bonded and fixed in the U-shaped groove; The outer surfaces of the two friction discs are provided with clips, and the friction discs and the structural support discs are fixed axially by rivets.

3. The aircraft carbon / carbon brake disc according to claim 2, characterized in that: The steel clamp is a U-shaped plate as a whole, and lugs extending outwards are symmetrically arranged at the open end of the side wall of the steel clamp, and the lugs can respectively press the surfaces of the two friction discs; The end of the lug and the end of the clip are provided with matched L-shaped notch structures.

4. The carbon / carbon brake disc according to claim 3, characterized in that: The connecting assembly is made of high-temperature metal material.

5. The method for preparing a carbon / carbon brake disc according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1, preparing a structural support plate; Step 1.1, prepare a density of 0.60-1.2 g / cm 3 A structural support plate preform; The structural support plate preform is prepared in the following manner: The single-layer carbon fiber mesh tire is alternately layered with a single-layer or multi-layer carbon fiber cloth, and the Z-direction fiber is introduced by needle punching process to obtain a density of 0.6-1.0g / cm 3 Quasi-three-dimensional needle-punched carbon fiber preform; Or the carbon fiber is woven once to form a density of 0.7 to 1.2 g / cm 3 Three-dimensional carbon fiber preform; Step 1.2, densification treatment: Chemical vapor infiltration treatment: Place the preform of the structural support plate into a chemical vapor infiltration device for chemical vapor infiltration treatment to obtain a density of 1.4-1.6 g / cm 3 A structural support disc blank; Liquid phase impregnation treatment: the structural support disc blank is placed in a liquid phase impregnation device for impregnation and curing treatment. After curing, the structural support disc blank is subjected to carbonization and cracking treatment by a carbonization device. The impregnation-curing-carbonization and cracking treatment is repeated 2-5 times to obtain a structure containing resin carbon / asphalt carbon. The density of the structure containing resin carbon / asphalt carbon is 1.8-2.2 g / cm 3 ; Step 1.3, high temperature heat treatment: subjecting the structure containing resin carbon / asphalt carbon to high temperature heat treatment to adjust the carbon phase structure inside the body; the high temperature heat treatment temperature is 1800-2500° C., and the holding time is 1-4 hours; Step 1.4, mechanically processing to obtain a structural support disk, and performing an anti-oxidation coating treatment on the structural support disk; Step 2, preparing a friction disc; Step 2.1, prepare a density of 0.15-0.6 g / cm 3 A friction disc preform; The friction disc preform is prepared in the following manner: Single or multi-layer carbon fiber webs are alternately layered with single-layer carbon fiber cloths, and Z-phase fibers are introduced by needle punching to obtain a density of 0.3-0.6 g / cm 3 Quasi-three-dimensional needle-punched carbon fiber preform; Or the carbon fiber mesh layer is needle-punched to obtain a density of 0.15-0.25g / cm 3 Pure carbon fiber mesh tire needle-punched structure; Step 2.2, subjecting the friction disc preform prepared in step 2.1 to chemical vapor infiltration densification treatment to obtain a density of 1.7 to 1.8 g / cm 3 A friction disc blank; Step 2.3, subjecting the friction disc blank obtained in step 2.2 to high temperature heat treatment at a temperature of 1800 to 2500° C. to adjust the carbon phase structure inside the blank, and the high temperature heat treatment holding time is 1 to 4 hours; Step 2.4, mechanically processing a friction disc, and performing an anti-oxidation coating treatment on the friction disc; Step 3, coaxially placing the obtained structural support disc between two friction discs, and fixing the edges of the friction discs and the structural support disc by a plurality of connecting components to obtain a carbon / carbon brake disc.

6. The preparation method according to claim 5, characterized in that: In step 1.2, the specific process of placing the structural support plate preform into a chemical vapor infiltration device for densification treatment is as follows: The chemical vapor infiltration device is evacuated until the pressure in the cavity is less than 0.5 kPa. After maintaining the pressure for 2 to 6 hours, the pressure in the cavity is no more than 1.5 kPa. After the pressure is maintained, the temperature in the chemical vapor infiltration device is raised to 900-1100°C, and then a mixture of natural gas and propane gas is introduced at a speed of 0.7-2 m / s for 100-200 hours of densification treatment to obtain a density of 1.2-1.5 g / cm 3 A structural support disc blank; The volume ratio of natural gas to propane gas in the mixed gas is 75-88:12-25.

7. The preparation method according to claim 6, characterized in that: In step 1.2, the preform of the structural support plate which has been subjected to the chemical vapor infiltration densification treatment is placed in a liquid phase impregnation device, and the structural support plate blank is impregnated and cured, and the process of carbonization and cracking treatment after curing is as follows: Impregnation treatment: evacuate the liquid phase impregnation device to a pressure less than 0.5 kPa, absorb the resin / asphalt impregnating agent into the cavity of the liquid phase impregnation device, and after impregnation for 0.5 to 1 hour, introduce inert gas into the cavity of the liquid phase impregnation device, adjust the pressure in the cavity to 3 to 5 MPa, and continue impregnation for 1 to 2 hours; Curing treatment: curing the structural support disc blank under normal pressure, with a curing temperature of 100 to 260°C and a curing time of 3 to 5 hours; Carbonization and cracking treatment: the solidified green body is placed in a carbonization device for carbonization and cracking treatment; the carbonization and cracking temperature is 800-1200°C, the pressure in the carbonization device cavity is less than 3KPa, and the insulation time is 2-5 hours.

8. The preparation method according to claim 7, characterized in that: The process of high temperature heat treatment in step 1.3 is as follows: placing the structural support disc blank in a high temperature heat treatment device; The inside of the high-temperature heat treatment device is evacuated until the pressure in the chamber is less than 0.5 kPa, and the pressure does not exceed 1.5 kPa after maintaining the pressure for 8 to 12 hours; the temperature in the high-temperature heat treatment device is increased to 1800 to 2500°C and maintained for 1 to 4 hours.

9. The preparation method according to claim 8, characterized in that: The process of chemical vapor infiltration densification treatment in step 2.2 is as follows: placing the friction disc preform into a chemical vapor infiltration device, adjusting the pressure in the cavity of the chemical vapor infiltration device to less than 0.5 kPa by vacuuming, and maintaining the pressure for 4 hours until the pressure in the cavity is no more than 1.5 kPa; After maintaining the pressure, the temperature in the chemical vapor infiltration device is raised to 900-1100°C, and then a mixture of natural gas and propane gas is introduced at a speed of 0.7-2 m / s for 300-600 hours of densification treatment to obtain a density of 1.7-1.8 g / cm 3 A friction disc blank; The volume ratio of natural gas to propane gas in the mixed gas is 75-88:12-25.

10. The preparation method according to claim 9, characterized in that: The process of high temperature treatment in step 2.3 is as follows: Placing the friction disc blank obtained in step 2.2 in a high temperature heat treatment device; The high-temperature heat treatment device is evacuated until the pressure in the chamber is less than 0.5 kPa, and the pressure does not exceed 1.5 kPa after maintaining the pressure for 8 to 12 hours; the temperature in the high-temperature heat treatment device is increased to 1800 to 2500°C and maintained for 1 to 4 hours.

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