Preparation method of aviation carbon-ceramic brake material

Abstract

The invention discloses a preparation method of an aviation carbon-ceramic brake material, and relates to the technical field of carbon-ceramic brake materials, and the preparation method comprises the following steps: preparing a prefabricated body: firstly stacking 4-6 layers of T700 chopped carbon fiber tire nets to form a blank core, performing three-dimensional orthogonal weaving on an outer layer by adopting T800 carbon fiber bundles to prepare the prefabricated body, and under the conditions that the frequency is 10-30kHz and the pressure is 0.8-1.0 MPa, performing heat preservation for 2-3 hours; interface bonding is enhanced through ultrasonic-assisted needling; composite densification: carrying out vacuum impregnation with polycarbosilane resin, doping 3wt% of boron carbide nanoparticles, and then carrying out chemical vapor deposition at 1100 DEG C; the composite structure of the T700 chopped carbon fiber tire net stacked blank core and the T800 carbon fiber three-dimensional orthogonal woven outer layer is adopted, dispersion strengthening of short fibers and structural integrity of long fibers are considered, the impact resistance and toughness of the prefabricated body can be improved, the pore distribution of the prefabricated body is more uniform in cooperation with the three-dimensional orthogonal woven structure, and the service life of the prefabricated body is prolonged. And a good foundation is laid for the subsequent densification step.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon-ceramic brake materials, and more particularly to a preparation method of aviation carbon-ceramic brake materials. Background Art

[0002] Carbon-ceramic brake materials are a new type of high-performance brake material, following the development of powder metallurgy brake materials and carbon-carbon brake materials. While retaining the excellent properties of ceramic materials, such as high-temperature resistance and oxidation resistance, carbon-ceramic brake materials overcome the critical drawbacks of ceramics, such as brittleness and poor reliability. Carbon-ceramic brake materials exhibit metal-like fracture behavior, are less susceptible to cracks, and are immune to catastrophic failure, making them a promising new generation of high-performance brake materials.

[0003] Currently, the main manufacturing processes for carbon / ceramic brake discs are long-fiber chemical vapor deposition (CVD) and short-fiber compression molding. CVD has a long production cycle (300-1000 hours) and high costs. During the deposition process, surface deposition is faster than internal deposition, which easily creates density gradients. Furthermore, the preparation process produces highly corrosive gas products. Furthermore, during the deposition process, dense carbon regions are more likely to form in the fiber bundle area, resulting in poor phase distribution uniformity across the friction interface, affecting friction and wear performance. Short-fiber compression molding, on the other hand, produces materials with poor mechanical properties, prone to fracture under impact loads, and exhibits poor safety.

[0004] Therefore, on the basis of ensuring the overall performance of carbon-ceramic brake materials, developing new carbon-ceramic brake material processes is of great significance for the application and promotion of carbon-ceramic brake materials. Based on the above problems, we provide a preparation method for aviation carbon-ceramic brake materials. Summary of the Invention

[0005] In order to solve the problems raised in the above background technology, the present invention provides a method for preparing an aviation carbon-ceramic brake material.

[0006] The present invention provides a method for preparing an aviation carbon ceramic brake material using the following technical solutions:

[0007] A method for preparing an aviation carbon-ceramic brake material comprises the following steps:

[0008] S1: Preform preparation: T700 chopped carbon fiber webs are stacked to form a core, with 4 to 6 layers. The outer layer is made of T800 carbon fiber bundles woven in a three-dimensional orthogonal pattern to form a preform. Ultrasonic-assisted needling is performed at a frequency of 10 to 30 kHz and a pressure of 0.8 to 1.0 MPa to enhance interfacial bonding.

[0009] S2: Composite densification: vacuum impregnation of polycarbosilane resin and doping with 3 wt% boron carbide nanoparticles, followed by chemical vapor deposition (CVD) at 1100 °C;

[0010] S3: Reactive silicon infiltration: In an inert gas atmosphere, pulse siliconization is carried out at 1400-1500℃ for 3-5 hours to obtain a density of 2.0-2.3g / cm 3 Carbon ceramic brake material.

[0011] Preferably, the thickness of the preform core is 40-60 μm, the thickness of the preform is 80-120 μm, the ultrasonic acupuncture frequency is preferably 28 kHz, and the acupuncture pressure is preferably 0.9 MPa.

[0012] Preferably, a ceramic slurry of silicon carbide and graphite powder is injected during the needling process, wherein the mass ratio of silicon carbide to graphite powder in the ceramic slurry is 1:0.2-0.3, and heat treatment is performed at 1400-1650°C for 5-10 hours to promote the formation of the ceramic phase and the interface bonding between the carbon fiber and the ceramic.

[0013] Preferably, the viscosity of the polycarbosilane resin is 100-200 cP, the vacuum impregnation pressure is 0.8-1.0 MPa, the temperature is 150-200° C., and the duration is 30-60 min. After each impregnation, it is necessary to drip dry for 30-60 min and cure at 200-250° C.

[0014] Preferably, the gas flow ratio of the chemical vapor deposition (CVD) is CH3SiCl3:H2=1:4, the deposition time is 30 to 60 minutes, and a rare earth precursor doped with 0.1 to 0.5 wt% yttrium oxide or zirconium oxide is pulse-injected during the process.

[0015] Preferably, the pulse injection frequency of the rare earth precursor is 20-50 Hz, and the pulse width is 100-150 ms.

[0016] Preferably, the pulse siliconizing specifically comprises the following steps:

[0017] 1) maintaining an initial temperature of 850° C. to 900° C., a heating rate of 10° C. / min, and a duration of 30 to 60 min to form a SiC thin layer in the pores of the carbon fiber preform;

[0018] 2) Raising the temperature to 1400°C to 1450°C and holding the temperature for 60 to 140 minutes to increase the penetration depth of silicon and ensure that the silicon source can fully penetrate into the inner area of ​​the carbon fiber preform;

[0019] 3) Raise the temperature to 1480°C to 1500°C and keep it at this temperature for 120 to 160 minutes to form a thicker SiC layer and fill the remaining pores in the carbon fiber preform to densify the material, and finally cool it to room temperature.

[0020] Preferably, the purity of the prepared silicon melt is ≥99.999%, which is achieved by protection with argon or nitrogen, and the residual silicon content is controlled to 1.2-1.8 wt% by vacuum annealing after siliconization.

[0021] In summary, the present invention has the following beneficial technical effects:

[0022] 1. By adopting a composite structure of T700 short-cut carbon fiber web stacked embryo core and T800 carbon fiber three-dimensional orthogonal braided outer layer, the dispersion reinforcement of short fibers and the structural integrity of long fibers are taken into account, which can improve the impact resistance and toughness of the preform. In addition, the three-dimensional orthogonal braided structure makes the pore distribution of the preform more uniform, laying a good foundation for the subsequent densification step.

[0023] 2. Ultrasonic-assisted needling is used to improve the interface wettability between the fiber and the matrix by utilizing the ultrasonic cavitation effect. At the same time, silicon carbide-graphite ceramic slurry is injected during needling and heat-treated to further promote the formation of the ceramic phase and the interface bonding between the carbon fiber and the ceramic matrix, thereby reducing interface defects.

[0024] 3. By vacuum impregnation of polycarbosilane resin to fill the pores of the preform, a continuous resin matrix can be formed and doped with 3wt% boron carbide nanoparticles. The high hardness of the boron carbide nanoparticles can be used to improve the wear resistance of the material. Moreover, chemical vapor deposition (CVD) can be used to further fill the micropores and increase the material density. At the same time, pulse injection of yttrium oxide rare earth precursor can refine the grains and improve the high-temperature stability and thermal shock resistance of the material. The combined process of impregnation and CVD is used to make the silicon carbide ceramic phase more evenly distributed in the matrix, which can avoid the ceramic phase agglomeration problem that may be caused by a single process and improve the overall mechanical consistency of the material. DETAILED DESCRIPTION

[0025] The present invention is described in further detail below.

[0026] Example 1

[0027] Preform preparation: T700 chopped carbon fiber webs were stacked to form a core, with 6 layers stacked to obtain a preform core with a thickness of 60 μm. T800 carbon fiber bundles were three-dimensionally orthogonally woven on the outer layer to obtain a preform with a thickness of 120 μm.

[0028] Ultrasonic-assisted acupuncture: An ultrasonic generator is used to apply high-frequency vibration at a frequency of 28kHz and a pressure of 0.9MPa to the acupuncture needle to enhance interfacial bonding;

[0029] Ceramic slurry injection and curing: During the needling process, a ceramic slurry of silicon carbide and graphite powder was injected. The mass ratio of silicon carbide to graphite powder in the ceramic slurry was 1:0.2, and the slurry was heat treated at 1500℃ for 6 hours to promote the formation of the ceramic phase and the interface bonding between the carbon fiber and the ceramic.

[0030] Vacuum impregnation: Using polycarbosilane resin with a viscosity of 180 cP and doped with 3 wt% boron carbide nanoparticles, vacuum impregnation was performed at a pressure of 1.0 MPa and a temperature of 200°C for 40 minutes, repeated four times. After each impregnation, the resin was allowed to drip dry for 40 minutes and then cured at 250°C.

[0031] Chemical vapor deposition (CVD): At 1100°C, a flow rate ratio of CH3SiCl3:H2 = 1:4 was injected for 60 minutes. During this process, a rare earth precursor doped with 0.4 wt% yttria or zirconium oxide was pulsed at a frequency of 40 Hz and a pulse width of 120 ms.

[0032] Reactive silicon infiltration: In an argon or nitrogen atmosphere, the following steps are performed to prepare a carbon-ceramic brake material having a silicon melt purity of ≥99.999% and a residual silicon content of 1.2-1.8 wt%:

[0033] 1) Maintaining an initial temperature of 900°C, heating at a rate of 10°C / min for 50 min, the silicon source begins to melt and enters the pores of the carbon fiber preform through capillary action, reacting with carbon to form a SiC layer, and forming a SiC thin layer in the pores of the carbon fiber preform;

[0034] 2) Raise the temperature to 1400°C and hold for 100 minutes to increase the penetration depth of silicon and ensure that the silicon source can fully penetrate into the inner area of ​​the carbon fiber preform;

[0035] 3) Raise the temperature to 1500°C and keep it at this temperature for 160 minutes to form a thicker SiC layer and fill the remaining pores in the carbon fiber preform to densify the material, and finally cool it to room temperature.

[0036] Example 2

[0037] Preform preparation: T700 chopped carbon fiber webs were stacked to form a core, with 6 layers stacked to obtain a preform core with a thickness of 60 μm. T800 carbon fiber bundles were three-dimensionally orthogonally woven on the outer layer to obtain a preform with a thickness of 120 μm.

[0038] Ultrasonic-assisted acupuncture: The ultrasonic generator applies high-frequency vibration of 20kHz and 0.8MPa to the acupuncture needle to enhance the interface bonding;

[0039] Ceramic slurry injection and curing: During the needling process, a ceramic slurry of silicon carbide and graphite powder was injected. The mass ratio of silicon carbide to graphite powder in the ceramic slurry was 1:0.2, and the slurry was heat treated at 1400℃ for 5 hours to promote the formation of the ceramic phase and the interface bonding between the carbon fiber and the ceramic.

[0040] Vacuum impregnation: Using polycarbosilane resin with a viscosity of 100 cP and doped with 3 wt% boron carbide nanoparticles, vacuum impregnation was performed at a pressure of 0.8 MPa and a temperature of 150°C for 30 minutes, repeated four times. After each impregnation, the resin was allowed to drip dry for 30 minutes and then cured at 200°C.

[0041] Chemical vapor deposition (CVD): At 1100°C, a flow rate ratio of CH3SiCl3:H2 = 1:4 was injected for 30 minutes. During this process, a rare earth precursor doped with 0.1 wt% yttria or zirconium oxide was pulsed at 20 Hz and a pulse width of 100 ms.

[0042] Reactive silicon infiltration: In an argon or nitrogen atmosphere, the following steps are performed to prepare a carbon-ceramic brake material having a silicon melt purity of ≥99.999% and a residual silicon content of 1.2-1.8 wt%:

[0043] 1) Maintaining an initial temperature of 850°C, heating at a rate of 10°C / min for 30 min, the silicon source begins to melt and enters the pores of the carbon fiber preform through capillary action, reacting with carbon to form a SiC layer, and forming a SiC thin layer in the pores of the carbon fiber preform;

[0044] 2) Raise the temperature to 1400°C and hold for 60 minutes to increase the penetration depth of silicon and ensure that the silicon source can fully penetrate into the inner area of ​​the carbon fiber preform;

[0045] 3) The temperature was raised to 1480°C and kept at this temperature for 120 min to form a thicker SiC layer and fill the remaining pores in the carbon fiber preform to densify the material, and finally the temperature was lowered to room temperature.

[0046] Example 3

[0047] Preform preparation: T700 chopped carbon fiber webs were stacked to form a core, with 5 layers stacked to obtain a preform core with a thickness of 50 μm. T800 carbon fiber bundles were three-dimensionally orthogonally woven on the outer layer to obtain a preform with a thickness of 100 μm.

[0048] Ultrasonic-assisted acupuncture: The ultrasonic generator applies high-frequency vibration of 20kHz and 0.8MPa to the acupuncture needle to enhance the interface bonding;

[0049] Ceramic slurry injection and curing: During the needling process, ceramic slurry of silicon carbide and graphite powder was injected. The mass ratio of silicon carbide to graphite powder in the ceramic slurry was 1:0.2, and heat treated at 1500℃ for 5h to promote the formation of ceramic phase and the interface bonding between carbon fiber and ceramic.

[0050] Vacuum impregnation: Using polycarbosilane resin with a viscosity of 150 cP and doped with 3 wt% boron carbide nanoparticles, vacuum impregnation was performed at a pressure of 0.9 MPa and a temperature of 180°C for 40 minutes, repeated four times. After each impregnation, the resin was allowed to drip dry for 40 minutes and then cured at 200°C.

[0051] Chemical vapor deposition (CVD): At 1100°C, a flow rate ratio of CH3SiCl3:H2 = 1:4 was injected for 60 minutes. During this process, a rare earth precursor doped with 0.5 wt% yttria or zirconium oxide was pulsed at a frequency of 40 Hz and a pulse width of 120 ms.

[0052] Reactive silicon infiltration: In an argon or nitrogen atmosphere, the following steps are performed to prepare a carbon-ceramic brake material having a silicon melt purity of ≥99.999% and a residual silicon content of 1.2-1.8 wt%:

[0053] 1) Maintaining an initial temperature of 850°C, heating at a rate of 10°C / min for 50 min, the silicon source begins to melt and enters the pores of the carbon fiber preform through capillary action, reacting with carbon to form a SiC layer, and forming a SiC thin layer in the pores of the carbon fiber preform;

[0054] 2) Raise the temperature to 1400°C and hold for 100 minutes to increase the penetration depth of silicon and ensure that the silicon source can fully penetrate into the inner area of ​​the carbon fiber preform;

[0055] 3) Raise the temperature to 1480°C and hold for 160 min to form a thicker SiC layer and fill the remaining pores in the carbon fiber preform to densify the material, and finally cool to room temperature.

[0056] Example 4

[0057] Preform preparation: T700 chopped carbon fiber webs were stacked to form a core, with 6 layers stacked to obtain a preform core with a thickness of 60 μm. T800 carbon fiber bundles were three-dimensionally orthogonally woven on the outer layer to obtain a preform with a thickness of 120 μm.

[0058] Ultrasonic-assisted acupuncture: An ultrasonic generator is used to apply high-frequency vibration at a frequency of 28kHz and a pressure of 1.0MPa to the acupuncture needle to enhance interfacial bonding;

[0059] Ceramic slurry injection and curing: During the needling process, a ceramic slurry of silicon carbide and graphite powder was injected. The mass ratio of silicon carbide to graphite powder in the ceramic slurry was 1:0.2, and the slurry was heat treated at 1650°C for 6 hours to promote the formation of the ceramic phase and the interface bonding between the carbon fiber and the ceramic.

[0060] Vacuum impregnation: Using polycarbosilane resin with a viscosity of 200 cP and doped with 3 wt% boron carbide nanoparticles, vacuum impregnation was performed at a pressure of 1.0 MPa and a temperature of 200°C for 60 minutes, repeated four times. After each impregnation, the resin was allowed to drip dry for 60 minutes and then cured at 200-250°C.

[0061] Chemical vapor deposition (CVD): At 1100°C, a flow rate ratio of CH3SiCl3:H2 = 1:4 was injected for 60 minutes. During this process, a rare earth precursor doped with 0.5 wt% yttria or zirconium oxide was pulsed at a frequency of 50 Hz and a pulse width of 150 ms.

[0062] Reactive silicon infiltration: In an argon or nitrogen atmosphere, the following steps are performed to prepare a carbon-ceramic brake material having a silicon melt purity of ≥99.999% and a residual silicon content of 1.2-1.8 wt%:

[0063] 1) Maintaining an initial temperature of 900°C, heating at a rate of 10°C / min for 60 min, the silicon source begins to melt and enters the pores of the carbon fiber preform through capillary action, reacting with carbon to form a SiC layer, and forming a SiC thin layer in the pores of the carbon fiber preform;

[0064] 2) Raise the temperature to 1450°C and hold for 140 minutes to increase the penetration depth of silicon and ensure that the silicon source can fully penetrate into the inner area of ​​the carbon fiber preform;

[0065] 3) Raise the temperature to 1500°C and keep it at this temperature for 160 minutes to form a thicker SiC layer and fill the remaining pores in the carbon fiber preform to densify the material, and finally cool it to room temperature.

[0066]

[0067] Table 1 Comparative table of carbon ceramic brake material properties obtained from Examples 1 to 4

[0068] Example 5

[0069] The steps and parameters are the same as those in Example 1, except that the ultrasound-assisted acupuncture reaction step is omitted.

[0070] Example 6

[0071] The steps and parameters are the same as those in Example 1, except that the chemical vapor deposition (CVD) reaction step is omitted.

[0072] Example 7

[0073] The steps and parameters are the same as those in Example 1, except that the vacuum impregnation reaction step is omitted.

[0074] Friction performance Bending strength MPa Porosity% Example 1 0.35 390 2.9 Example 5 0.38 380 2.9 Example 6 0.38 395 3.0 Example 7 0.36 380 2.9

[0075] Table 2: Comparative table of carbon ceramic brake material properties obtained in Examples 1, 5, 6, and 7

[0076] It can be seen that carbon-ceramic brake materials with higher density, high strength and good friction performance can be prepared through processes such as three-dimensional weaving, ultrasonic-assisted needling, resin densification, CVD deposition and reactive silicon infiltration.

[0077] The standard parts used in the present invention can all be purchased from the market, and special-shaped parts can all be customized according to the instructions. The specific connection methods of each part adopt conventional means such as mature bolts, rivets, welding, etc. in the existing technology. The machinery, parts and equipment all adopt conventional models in the existing technology, and the circuit connection adopts the conventional connection method in the existing technology, which will not be described in detail here.

[0078] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an aviation carbon ceramic brake material, characterized in that: The following steps are involved: S1: Preform preparation: T700 chopped carbon fiber webs are stacked to form a core, with 4 to 6 layers. The outer layer is made of T800 carbon fiber bundles woven in a three-dimensional orthogonal pattern to form a preform. Ultrasonic-assisted needling is performed at a frequency of 20 to 30 kHz and a pressure of 0.8 to 1.0 MPa to enhance interfacial bonding. S2: Composite densification: vacuum impregnation of polycarbosilane resin and doping with 3 wt% boron carbide nanoparticles, followed by chemical vapor deposition at 1100 °C; S3: Reactive silicon infiltration: In an inert gas atmosphere, pulse siliconization is carried out at 1400-1500℃ for 3-5 hours to obtain a density of 2.0-2.3g / cm 3 Carbon ceramic brake material.

2. The method for preparing an aviation carbon ceramic brake material according to claim 1, characterized in that: The thickness of the preform embryo core is 40-60 μm, the thickness of the preform is 80-120 μm, the ultrasonic acupuncture frequency is preferably 28 kHz, and the acupuncture pressure is preferably 0.9 MPa.

3. The method for preparing an aviation carbon ceramic brake material according to claim 1, characterized in that: During the needling process, a ceramic slurry of silicon carbide and graphite powder is injected, wherein the mass ratio of silicon carbide to graphite powder in the ceramic slurry is 1:0.2-0.3, and the slurry is heat treated at 1400-1650°C for 5-10 hours to promote the formation of the ceramic phase and the interface bonding between the carbon fiber and the ceramic.

4. The method for preparing an aviation carbon ceramic brake material according to claim 1, characterized in that: The viscosity of the polycarbosilane resin is 100-200 cP, the vacuum impregnation pressure is 0.8-1.0 MPa, the temperature is 150-200° C., the duration is 30-60 minutes, and it is repeated 3-4 times. After each impregnation, it needs to be dripped for 30-60 minutes and cured at 200-250° C.

5. The method for preparing an aviation carbon ceramic brake material according to claim 1, characterized in that: The gas flow ratio of the chemical vapor deposition is CH3SiCl3:H2=1:4, the deposition time is 30-60 minutes, and a rare earth precursor doped with 0.1-0.5wt% yttrium oxide or zirconium oxide is pulse-injected during the process.

6. The method for preparing an aviation carbon-ceramic brake material according to claim 5, characterized in that: The pulse injection frequency of the rare earth precursor is 20-50 Hz, and the pulse width is 100-150 ms.

7. The method for preparing an aviation carbon-ceramic brake material according to claim 1, characterized in that: The specific steps of the pulse siliconizing are: 1) maintaining an initial temperature of 850° C. to 900° C., a heating rate of 10° C. / min, and a duration of 30 to 60 min to form a SiC thin layer in the pores of the carbon fiber preform; 2) Raising the temperature to 1400°C to 1450°C and holding the temperature for 60 to 140 minutes to increase the penetration depth of silicon and ensure that the silicon source can fully penetrate into the inner area of ​​the carbon fiber preform; 3) Raise the temperature to 1480°C to 1500°C and keep it at this temperature for 120 to 160 minutes to form a thicker SiC layer and fill the remaining pores in the carbon fiber preform to densify the material, and finally cool it to room temperature.

8. The method for preparing an aviation carbon-ceramic brake material according to any one of claims 1 to 7, characterized in that: The purity of the prepared silicon melt is ≥99.999%, which is achieved through argon or nitrogen protection, and the residual silicon content is controlled at 1.2-1.8wt% through vacuum annealing after siliconization.

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