CN119430971B

CN119430971B - Carbon-ceramic composite material, preparation method thereof, and carbon-ceramic brake disc

Info

Publication number: CN119430971B
Application number: CN202411595805.5A
Authority: CN
Inventors: 姜钰国; 周迎春; 张杨; 何佳豪; 张鸿鹏
Original assignee: Suzhou Haten Technology Co ltd
Current assignee: Suzhou Haten Technology Co ltd
Priority date: 2024-11-11
Filing date: 2024-11-11
Publication date: 2025-08-22
Anticipated expiration: 2044-11-11
Also published as: CN119430971A

Abstract

The present invention discloses a carbon-ceramic composite material, a preparation method thereof, and a carbon-ceramic brake disc. The preparation method of the carbon-ceramic composite material comprises the following steps: uniformly mixing silicon carbide, carbon fiber, and an additive to obtain a carbon-ceramic preformed powder; placing the carbon-ceramic preformed powder in a mold of a direct current rapid sintering device and applying a first preparation operation to obtain a sample to be sintered; starting the heating system of the direct current rapid sintering device, heating the sample to a first temperature, applying a second preparation operation to the sample to be sintered, then gradually heating it to a second temperature and maintaining the temperature for a period of time; shutting off the heating system and allowing it to cool naturally to obtain the carbon-ceramic composite material. The preparation method provided by the present application has a simple preparation process, low cost, and short time consumption. The carbon-ceramic composite material finally prepared has uniform phase distribution and good mechanical properties, which is conducive to a wide range of applications.

Description

Carbon ceramic composite material, preparation method thereof and carbon ceramic brake disc

Technical Field

The invention relates to the technical field of composite materials, in particular to a carbon-ceramic composite material, a preparation method thereof and a carbon-ceramic brake disc.

Background

With the development of modern vehicles, in order to ensure the safety of a brake system and the reliability of friction transmission, the requirements on the brake system are more strict, and the brake system has the characteristics of high and stable friction coefficient, good wear resistance, strong environmental adaptability, stable high-temperature mechanical property, stable friction process, low noise, low cost, simple process, environment friendliness, reliability and the like.

The prior powder metallurgy type metal friction material can not meet the requirements, the carbon ceramic composite material is used as an aircraft structural member in early stage, is used in the friction field since the 90 th century, and is widely applied to the fields of new energy automobiles, high-end automobile fuel automobiles and reformation automobiles.

The reaction infiltration method (RMI) is a mainstream production process of the carbon ceramic brake disc in the current market, and is divided into a short fiber carbon ceramic disc and a long fiber carbon ceramic disc according to different prefabricated bodies. And (3) using a vacuum sintering furnace to distribute a layer of silicon powder on the surface of the prepared preform, heating to 1400-1500 ℃, melting the silicon powder, penetrating liquid silicon into the preform by capillary action, and performing chemical reaction with the preform to generate silicon carbide. The method is a relatively simple process for preparing the carbon ceramic, but the processing procedures are too many, so that the popularization of the carbon ceramic brake disc is limited by some problems. The preparation of the prefabricated body mainly comprises the following steps of preparing the prefabricated body, namely, poor material distribution uniformity of the short fiber compression molding prefabricated body, unstable surface friction performance and poor mechanical property after the prefabricated body is manufactured into a carbon ceramic disc, uneven graphite films in partial areas can appear after the needled prefabricated body is subjected to CVI process surface coating to block a passage, the next step of infiltration of liquid silicon is affected, the carbon felt and the non-woven cloth are structurally different, only the carbon felt can be used as a friction layer, the service life is limited, and the melting point of the silicon is only 1410 ℃ when the silicon remains in a phase, the stability of the high-temperature mechanical property and the stability of the surface friction property of the carbon ceramic disc are affected, and the passage is blocked by silicon carbide generated by reaction, so that the infiltration is affected.

Disclosure of Invention

The technical problem to be solved by the embodiment of the invention is to provide the carbon-ceramic composite material, the preparation method thereof and the carbon-ceramic brake disc, so that the processing time can be shortened, and the prepared carbon-ceramic composite material is uniform in phase and good in high-temperature performance.

The invention provides a preparation method of a carbon ceramic composite material, which comprises the following steps of uniformly mixing silicon carbide, carbon fibers and an auxiliary agent to obtain carbon ceramic prefabricated powder, placing the carbon Tao Yu powder into a die of a direct current rapid sintering device, applying a first preparation operation means to obtain a sample to be sintered, starting a heating system of the direct current rapid sintering device, gradually increasing direct current to heat the sample to be sintered, applying a second preparation operation means to the sample to be sintered after the heating system is gradually increased to a first temperature, continuously increasing the direct current, gradually heating the sample to be sintered to the second temperature, preserving heat for a period of time, closing the heating system, and naturally cooling the sample to obtain the carbon ceramic composite material.

In one possible implementation mode, the first preparation method comprises the steps of selecting a die with a proper size, isolating the inside by graphite paper, filling the carbon Tao Yu powder into the die, pre-compacting under the pressure of 1-5 MPa, and wrapping the carbon felt with heat insulation.

In one possible implementation, the second preparation operation means comprises gradually pressurizing the mold at a pressure increase rate of (1-10) MPa/min, applying a pressure of (30-50) MPa.

In one possible implementation, the auxiliary agent is selected from at least one of Al4SiC, B4C or a metal oxide mixture, wherein the metal oxide mixture at least comprises a first metal oxide and a second metal oxide, the first metal oxide is selected from at least one of Al2O3 and Y2O3, and the second metal oxide is selected from at least one of MgO, caO, la2O3, sc2O3 and Er2O 3.

In one possible implementation mode, the mass ratio of the silicon carbide to the carbon fiber to the auxiliary agent is 1 (0.5-2): 0.01-0.1.

In one possible implementation, the carbon fiber has a length of 5mm to 30mm.

In one possible implementation, the first temperature range is 700 ℃ and the temperature rising rate is 50-100 ℃ per minute.

In one possible implementation mode, the second temperature range is 1600-2100 ℃, the temperature rising rate of gradually rising to the second temperature is 10-50 ℃ per minute, and the heat preservation time is 20 min-2 h.

Correspondingly, the invention also provides a carbon ceramic composite material which is prepared by the preparation method of any one of the above.

Correspondingly, the invention also provides a carbon ceramic brake disc, which is prepared by applying the carbon ceramic composite material.

The implementation of the invention has the following beneficial effects:

The preparation method of the carbon ceramic composite material provided by the embodiment of the application takes silicon carbide powder and carbon fiber short fibers as raw materials, the silicon carbide powder and the carbon fiber short fibers are mixed to form uniform powder, and the uniform powder is directly sintered by using a flash sintering process, so that the preparation process is simple, the cost is low, and the time consumption is short. In addition, the raw materials used in the preparation method provided by the embodiment of the application do not use silicon monomers, and silicon does not need to be melted into liquid silicon, and a infiltration process is not needed. And because free silicon is not contained, the carbon ceramic composite material prepared by the preparation process provided by the application has good high-temperature performance. Meanwhile, the raw materials and the preparation process are simple, the raw materials can be uniformly mixed, and the finally prepared carbon-ceramic composite material is uniform in phase distribution, good in mechanical property and favorable for wide application.

The carbon-ceramic composite material provided by the embodiment of the application has the advantages of uniform phase, excellent mechanical property, stable friction performance, high temperature resistance, high density and the like, and is favorable for wide application.

Drawings

FIG. 1 is a SEM image (1000 times) of the fracture surface of a carbon-ceramic composite material prepared in example 1;

FIG. 2 is a SEM image (5000 times) of the fracture surface of the carbon-ceramic composite material prepared in example 1;

FIG. 3 is an EDS layered image of the carbon-ceramic composite material prepared in example 1;

FIG. 4 is an EDS layered image-C of the carbon ceramic composite material prepared in example 1;

FIG. 5 is an EDS layered image-Si of the carbon ceramic composite material prepared in example 1.

Detailed Description

In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the invention, whereby the invention is not limited to the specific embodiments disclosed below.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

The embodiment of the application provides a preparation method of a carbon ceramic composite material. The preparation method of the carbon ceramic composite material comprises the following steps:

S110, uniformly mixing silicon carbide, carbon fibers and an auxiliary agent to obtain a carbon Tao Yu powder.

The operation of uniformly mixing the silicon carbide, the carbon fiber and the auxiliary agent can be to add the silicon carbide, the carbon fiber and the auxiliary agent into a stirring device at the same time for uniform stirring, and the raw materials are uniformly distributed through stirring. Alternatively or preferably, the auxiliary agent and the carbon fiber may be mixed uniformly before adding the silicon carbide powder. Alternatively or preferably, the auxiliary agent and the silicon carbide powder may be mixed uniformly before adding the carbon fiber. Thus, the method is favorable for fully and uniformly mixing raw materials, and further is favorable for uniform distribution of the phase of the final product.

Further, in one possible embodiment, the auxiliary agent is selected from at least one of Al ₄SiC,B₄ C or a mixture of metal oxides, wherein the mixture of metal oxides comprises at least a first metal oxide selected from at least one of Al ₂O₃ and Y ₂O₃ and a second metal oxide selected from at least one of MgO, caO, la ₂O₃,Sc₂O₃ and Er ₂O₃.

Alternatively or preferably, the metal oxide mixture is selected from at least one of Al ₂O₃ and Y ₂O₃;Al₂O₃ and CaO, al ₂O₃ and MgO, al ₂O₃,Y₂O₃, mgO and CaO, Y ₂O₃ and La ₂O₃;Y₂O₃ and S ₂O₃, or Al ₂O₃ and Er ₂O₃.

Alternatively or preferably, the metal oxide is mixed as a mixture of Al ₂O₃ and Y ₂O₃. Al ₂O₃ and Y ₂O₃ are capable of forming a Yttrium Aluminum Garnet (YAG) liquid phase at 1760 ℃ to promote densification. Further, the molar ratio of Al ₂O₃ to Y ₂O₃ is 1 (0.4 to 0.6).

Alternatively or preferably, the metal oxide is mixed as a mixture of Al ₂O₃ and CaO. Al ₂O₃ and CaO form a liquid phase at 1360-1500 ℃ to promote densification. Further, the molar ratio of Al ₂O₃ to CaO is 1 (0.8-1.2).

Alternatively or preferably, the metal oxide is mixed as a mixture of Al ₂O₃ and MgO. Al ₂O₃ and MgO generate magnesia-alumina spinel at 1450-1600 ℃ to generate liquid phase, so as to promote densification. Further, the molar ratio of Al ₂O₃ to MgO is 1 (0.4 to 0.6).

Alternatively or preferably, the metal oxide mixture is a mixture of Al ₂O₃,Y₂O₃, mgO and CaO. Al ₂O₃,Y₂O₃, mgO and CaO can act together to form a liquid phase, and densification is promoted. Further, the molar ratio of Al ₂O₃,Y₂O₃, mgO and CaO is 1 (0.4-0.6): (0.1-0.2): 0.1.

Alternatively or preferably, the metal oxide mixture is a mixture of Y ₂O₃ and La ₂O₃. The mixture of Y ₂O₃ and La ₂O₃ is above 2000 ℃, and the rare earth element can act with oxygen on the surface of silicon carbide, so that the oxygen content is reduced, densification is promoted, and the thermal conductivity is improved. Further, the molar ratio of Y ₂O₃ to La ₂O₃ is (0.4 to 0.6): 1.

Alternatively or preferably, the metal oxide mixture is a mixture of Y ₂O₃ and S ₂O₃. The mixture of Y ₂O₃ and S ₂O₃ is above 2050 ℃, and the rare earth element can act with oxygen on the surface of silicon carbide, so that the oxygen content is reduced, the densification is promoted, and the thermal conductivity is improved. Further, the molar ratio of Y ₂O₃ to S ₂O₃ is (0.2 to 0.4): 1.

Alternatively or preferably, the metal oxide mixture is a mixture of Al ₂O₃ and Er ₂O₃. The mixture of Al ₂O₃ and Er ₂O₃ can form Er ₃Al₅O₁₂, promote grain refinement and improve performance. Further, the molar ratio of Al ₂O₃ to Er ₂O₃ is (0.4-0.6): 1.

Alternatively or preferably, the promoter is Al ₄SiC.Al₄ SiC having a low density and high melting point, decomposing at 1700 ℃, carbon can promote grain refinement, and Al activator enhances grain boundary diffusion.

Alternatively or preferably, the aid B ₄C.B₄ C may form a co-melt phase with silicon carbide to promote densification.

In a possible implementation manner, optionally or preferably, the mass ratio of the silicon carbide to the carbon fiber to the auxiliary agent is 1 (0.5-2): 0.01-0.1. The mass ratio of the silicon carbide to the carbon fiber to the auxiliary agent is 1 (0.5-1.5) to 0.05. Optionally or preferably, the mass ratio of the silicon carbide, the carbon fiber and the auxiliary agent is 1:0.5:0.05, 1:1:0.05 or 1:1.5:0.05.

In one possible implementation, the length of the carbon fiber is 5 mm-30 mm. Optionally or preferably, the length of the carbon fiber is 10-25 mm. Optionally or preferably, the length of the carbon fiber is 10-20 mm. Alternatively or preferably, the carbon fibers have a length of 10mm, 15mm or 20mm. Alternatively or preferably, the carbon fibers have a length of 15mm.

And S120, placing the carbon Tao Yu powder into a die of a direct current rapid sintering device, and applying a first preparation operation means to obtain a sample to be sintered.

In a feasible implementation mode, the first preparation method comprises the steps of selecting a die with a proper size, isolating the inside by graphite paper, filling the carbon Tao Yu powder into the die, pre-compacting under the pressure of 1-5 MPa, and wrapping the carbon felt with heat insulation. Pre-compaction can significantly increase the initial density of the sample and reduce porosity. The high-density sample is easier to form a compact structure in the direct current rapid sintering process, so that the mechanical strength and durability of the material are improved. Precompaction can reduce voids and cavities in the sample, making the material more uniform. The uniform structure reduces the generation of cracks and defects, and improves the overall performance and reliability of the material. Pre-compaction allows the sample to be better shaped in the mold, ensuring consistency in shape and size. The consistent shape and size are beneficial to subsequent processing and application, and the qualification rate and production efficiency of the product are improved. Precompaction contributes to a uniform distribution of fillers and additives in the sample. The evenly distributed filler and additive can better play the function, and improve the comprehensive properties of the material, such as electric conductivity, thermal conductivity and the like. The pre-compacted sample has a higher density and fewer voids, and the heat conduction path is shorter. In the rapid sintering or flash sintering process, heat can be transferred to the inside of the sample more uniformly, and local overheating and uneven sintering are avoided. Pre-compaction may enhance the interfacial bond between the carbon fibers and other fillers. The good interface combination can improve the mechanical property and fatigue resistance of the material. Precompaction can make the sample surface smoother and flatter. The smooth surface is beneficial to improving the appearance quality of the material, reducing surface defects and improving the market competitiveness of the product.

S130, starting a heating system of the direct current rapid sintering device, gradually increasing direct current to heat, applying a second preparation operation means to the sample to be sintered after heating to the first temperature, continuously increasing the direct current, gradually increasing the temperature to the second temperature, and preserving heat for a period of time.

Further, the rate of increase of the direct current was 1000A per minute. The step of increasing the direct current refers to increasing the direct current applied to the two ends of the die of the direct current rapid sintering device, namely, directly applied to the two ends of the powder body of the carbon Tao Yu. The carbon Tao Yu powder is heated by direct current.

In one possible implementation, the second preparation operation means comprises gradually pressing the die at a pressure increasing rate of 10MPa/min, and applying a pressure of 30-50 MPa. The rapid pressure rise causes rapid changes in pressure inside and outside the material, creating large thermal and mechanical stresses. These stresses can cause cracks, delaminations or breaks within the material, severely affecting the mechanical strength and integrity of the material. Rapid pressurization may result in rapid dissolution or escape of gas within the material. Uneven dissolution and escape of gas may form bubbles or voids within the material, reducing the density and mechanical properties of the material. Rapid boosting may result in non-uniform phase transitions within the material. Different regions may undergo different phase transformation processes, resulting in non-uniformity of the microstructure of the material, affecting its physical and chemical properties. The rapid pressure rise may make certain chemical reactions less than adequate. Substances that are not fully reacted may remain in the material, affecting the purity and performance of the material and even causing subsequent instability and degradation. The rapid pressure rise can result in excessive pressure gradients inside and outside the material. Such pressure gradients may cause stress concentrations within the material, increasing the risk of cracks and defects. Rapid pressure rise may result in a rapid rise in material surface pressure with a lag in internal pressure. Such pressure differences may cause the expansion coefficients of the material surface and the interior to be different, inducing internal stresses, further increasing the risk of cracking. The rapid pressure rise may not sufficiently densify the material during sintering. The density of the material is reduced, the porosity is increased, and the mechanical property is reduced. The rapid boosting has higher requirements on the pressure resistance and safety of the equipment. If the device cannot withstand the pressure change caused by rapid pressure rise, damage to the device or safety accidents may be caused. However, too slow a rate of boost may significantly increase the time of the overall heat treatment process. The production period is prolonged, the production efficiency is reduced, and the production cost is increased. The long boosting process consumes more energy. The energy consumption is increased, the production cost is increased, and the requirements of energy conservation and emission reduction are not met. While slow pressure build-up contributes to gradual escape of volatile materials, if the pressure build-up is too slow, these materials may begin to escape at lower pressures, resulting in incomplete escape. Residual volatile materials may recondense or react at a later high pressure stage, affecting the purity and performance of the material. Too slow a rate of pressure rise may result in non-uniform structural changes in the material at different stages. The microstructure and properties of the material may vary in different areas, affecting overall uniformity and consistency. Too slow a rate of pressure rise may result in pyrolysis products (e.g., gases, liquids) beginning to form at lower pressures, but with slower discharge rates. These products may accumulate inside the material, resulting in increased porosity, affecting the density and mechanical properties of the material. Too slow a rate of pressure rise may result in weak interfacial bonding inside the material. Poor interfacial bonding can affect the mechanical properties and durability of the material. Too slow a rate of boost may result in an extended operating time of the device at high pressure. The utilization rate of the equipment is reduced and the maintenance cost is increased. Too slow a rate of pressure rise may result in increased difficulty in temperature control because the temperature and pressure changes need to be coordinated. Improper temperature control can affect the performance and quality of the material.

In one possible implementation, the first temperature range is 700 ℃ and the temperature rising rate is 50-100 ℃. The sintering temperature is determined according to different sintering aids, and if the temperature is not proper, the product cannot be molded or has poor performance.

In one possible embodiment, the second temperature range is 1600 ℃ to 2100 ℃. The temperature rising rate of gradually rising to the second temperature is 10-50 ℃ per minute. The heating speed is too high, the local temperature of the product is too high, the performance is influenced, and the efficiency is influenced too slowly. Too slow a rate of temperature rise can significantly increase the time of the overall heat treatment process. The production period is prolonged, the production efficiency is reduced, and the production cost is increased. The heating process for a long time consumes more energy. The energy consumption is increased, the production cost is increased, and the requirements of energy conservation and emission reduction are not met. While slow heating facilitates gradual escape of volatile materials, if the heating is too slow, these materials may begin to volatilize at lower temperatures, resulting in incomplete escape. Residual volatile materials may recondense or react at a later high temperature stage, affecting the purity and performance of the material. Too slow a rate of temperature rise may result in non-uniform structural changes in the material at different stages. The microstructure and properties of the material may vary in different areas, affecting overall uniformity and consistency. Too slow a rate of temperature rise may result in pyrolysis products (e.g., gases, liquids) beginning to form at lower temperatures, but at slower rates of discharge. These products may accumulate inside the material, resulting in increased porosity, affecting the density and mechanical properties of the material. Too slow a rate of temperature rise may result in weak interfacial bonding within the material. Poor interfacial bonding can affect the mechanical properties and durability of the material. Too slow a rate of temperature rise can result in extended operating times of the device at high temperatures. The utilization rate of the equipment is reduced and the maintenance cost is increased. Meanwhile, the rapid temperature rise can cause the temperature difference between the inside and the outside of the material to be increased, and larger thermal stress is generated. Thermal stresses can cause cracks, delamination, or breakage within the material, severely affecting the mechanical strength and integrity of the material. The rapid temperature rise causes the volatile substances (e.g., moisture, solvents, etc.) within the material to rapidly vaporize. The gas can not escape in time, bubbles or holes can be formed in the material, and the density and mechanical property of the material are reduced. Rapid temperature increases may cause non-uniformity of phase changes within the material. Different regions may undergo different phase transformation processes, resulting in non-uniformity of the microstructure of the material, affecting its physical and chemical properties. Rapid heating may result in rapid formation of pyrolysis products (e.g., gases, liquids) within the material. These products may not be able to drain in time, resulting in increased internal pressure within the material, causing cracks or other defects. Rapid temperature increases can result in rapid increases in the surface temperature of the material, while internal temperatures lag. Such a temperature difference may cause the expansion coefficients of the surface and the interior to be different, inducing internal stresses, further increasing the risk of cracking. Rapid increases in temperature may not adequately densify the material during sintering. The density of the material is reduced, the porosity is increased, and the mechanical property is reduced. While rapid heating may shorten the heating time, it may result in energy waste. Too high a rate of temperature rise may result in reduced energy efficiency of the device, increasing production costs. Further, the second temperature is selected according to the kind and ratio of the auxiliary agent.

In one possible embodiment, the incubation time is from 20 minutes to 2 hours. Further, the heat preservation time needs to be correspondingly adjusted according to different auxiliary agents and parameter conditions.

The direct-current rapid sintering device comprises a pressurizing device, a vacuum chamber, a heating system, a high-voltage direct-current flash power supply, a control system and a cooling system. The method comprises the steps of placing raw materials in a mold composed of high-temperature ceramics and graphite, placing the raw materials in the center of the interior of a vacuum chamber and being constrained by the pressure of a pressurizing system, enabling a heating system to enter the interior of the vacuum chamber through the outer wall of the vacuum chamber to heat carbon ceramic prefabricated powder, enabling a high-voltage direct-current flash power supply to apply voltage to the graphite mold through water-cooled copper electrodes at the upper pressure head and the lower pressure head of the pressurizing device, when the method is used, providing the pre-heating temperature required by pre-flash heating for sintering carbon Tao Yu powder through a heating body of an auxiliary heating system, applying a certain pressure through the pressurizing device, applying a direct-current electric field to form flash burning after the temperature reaches a set value, realizing low-temperature rapid densification of the carbon ceramic prefabricated powder, enabling the high-voltage direct-current flash power supply to be controlled through a program, switching from voltage control to current control when the flash burning occurs, ending heating after a certain time, and then cooling to room temperature.

And S140, closing the heating system, and naturally cooling to obtain the carbon-ceramic composite material.

In addition, the preparation method of the carbon-ceramic composite material provided by the embodiment of the application has the advantages of simple and convenient raw material acquisition and low cost. By virtue of the development of domestic carbon fibers, the carbon fiber short fibers are guaranteed in terms of price, supply and performance, and the development of the photovoltaic industry leads to stable powder supply of micron-sized silicon carbide, so that the raw material acquisition and the cost are more convenient and cheaper compared with those of the prior art, and the preparation method of the carbon ceramic composite material provided by the embodiment of the application does not need to prepare a prefabricated body, has fewer working procedures, and greatly shortens the preparation time and the cost. The preparation method of the carbon-ceramic composite material provided by the embodiment of the application has short preparation time and can be completed in a few hours. A rapid hot pressing sintering (FHP) process is used, and a direct current power supply forms direct current electric field auxiliary sintering, so that crystal grains are prevented from growing up, and better mechanical properties are obtained. The preparation method of the carbon ceramic composite material provided by the embodiment of the application does not need reaction participation, and the carbon ceramic composite material is directly sintered by using silicon carbide powder, and the reaction participation is not needed in the sintering process, so that the high-temperature performance is not influenced by the existence of low-melting-point components in the object phase. The prior art needs the limitation of a preform, and the preform can lead to the phase unevenness of a finished product and the unstable surface friction performance after long-time use. The density of the carbon ceramic composite material prepared by the preparation method of the carbon ceramic composite material provided by the embodiment of the application is high, and the density of the sintered sample is close to complete density, so that defects formed in the sample by pores are avoided, and the performance is reduced.

In the prior art, the preparation method comprises the steps of preparing a prefabricated body, melting silicon into liquid state by using a reaction infiltration method (RMI), infiltrating the liquid state into the prefabricated body, generating silicon carbide by reaction, and cooling to obtain the carbon ceramic material.

In the prior art, a great amount of pores exist in a sample of a carbon ceramic material manufactured by a reaction infiltration method (RMI), the sample cannot be fully densified, and a great amount of unreacted silicon exists in the sample, so that the mechanical property and the surface friction property of the material are influenced. According to the invention, the silicon carbide powder is directly sintered through a rapid hot-pressing sintering (FHP) process, and is well combined with the surface of the carbon fiber, the density is close to complete densification, no reaction is involved, and no unreacted silicon affects the performance.

Because of the structural problem of the prefabricated body, the carbon ceramic material manufactured by the prior art has unstable surface friction performance, only one layer of the surface can be used as a friction material, and the friction performance of the surface after being worn off in the use process becomes unstable, so that the use is influenced. The invention has no structural difference because of powder sintering, and the usable volume is much larger than that of the prior art.

Correspondingly, the embodiment of the application also provides a carbon-ceramic composite material. The carbon ceramic composite material is prepared by the preparation method of any one of the above. The carbon-ceramic composite material provided by the embodiment of the application has the advantages of uniform phase, excellent mechanical property, stable friction performance, high temperature resistance, high density and the like, and is favorable for wide application.

Correspondingly, the embodiment of the application also provides a carbon ceramic brake disc. The carbon ceramic brake disc is prepared from the carbon ceramic composite material. The carbon ceramic brake disc provided by the embodiment of the application has all the advantages of the carbon ceramic composite material, and is not repeated here.

With reference to the foregoing embodiments, in order to make the technical solution of the present application more specific, clear and easy to understand, the technical solution of the present application will be illustrated, but it should be noted that the content to be protected by the present application is not limited to the following embodiments.

Example 1

Uniformly mixing silicon carbide, carbon fibers and an auxiliary agent B ₄ C according to the ratio of 1:0.66:0.05 to obtain carbon ceramic prefabricated powder;

Selecting a die with the diameter of 80mm, isolating the inside by graphite paper, filling a carbon Tao Yu powder into the die, pre-compacting under the pressure of 5MPa, and wrapping a heat-preserving carbon felt to be used as a sample to be sintered;

and 5MPa of pre-pressure is applied to the sample to be sintered, and the infrared alignment temperature measuring hole is adjusted. Starting a heating system, heating by increasing current at 1000A per minute, applying pressure of 50MPa to a die at a boosting rate of 5MPa/min after heating to 700 ℃, heating to 1900 ℃ at a heating rate of 50 ℃/min, and preserving heat for 30min;

And after sintering, closing the heating system and naturally cooling the sintered sample in the die to obtain the carbon-ceramic composite material.

Example 2

Substantially the same as in example 1, except that silicon carbide, carbon fiber and auxiliary B ₄ C were mixed in a mass ratio of 1:1:0.05.

Example 3

Substantially the same as in example 1, except that silicon carbide, carbon fiber and auxiliary B ₄ C were mixed in a mass ratio of 1:2:0.05.

Example 4

Substantially the same as in example 1, except that the auxiliary agent was a metal oxide mixture, the metal oxide mixture was a mixture of Al ₂O₃ and Y ₂O₃, the molar ratio of Al ₂O₃ to Y ₂O₃ was 1:0.55, the mass ratio of silicon carbide, carbon fiber and auxiliary agent was 1:2:0.05, after heating to 700 ℃, a pressure of 40MPa was applied to the mold at a rate of 5MPa/min, the temperature was raised at a rate of 30 ℃/min, the temperature was raised to 1600 ℃, and the temperature was maintained for 20min.

Example 5 is essentially the same as example 1 except that the promoter is a metal oxide mixture, the metal oxide mixture is a mixture of La ₂O₃ and Y ₂O₃, the molar ratio of La ₂O₃ to Y ₂O₃ is 1:0.35, the mass ratio of silicon carbide, carbon fiber and promoter is 1:2:0.05, after heating to 700 ℃, a pressure of 40MPa is applied to the mold at a rate of 10MPa/min, the temperature is raised at a rate of 30 ℃/min, the temperature is raised to 2100 ℃, and the temperature is maintained for 2 hours.

Example 6

Substantially the same as in example 4, except that the mass ratio of silicon carbide, carbon fiber and auxiliary agent was 1:2:0.01.

Example 7

Substantially the same as in example 4, except that the mass ratio of silicon carbide, carbon fiber and auxiliary agent was 1:2:0.1.

Example 8

Substantially the same as in example 4, except that after heating to 700 ℃, a pressure of 40MPa was applied to the die at a rate of 10MPa/min, and the temperature was raised to 1700 ℃ at a rate of 50 ℃/min, and the temperature was maintained for 20min.

Example 9

Substantially the same as in example 4, except that the auxiliary agent was a metal oxide mixture, the metal oxide mixture was a mixture of Al ₂O₃,Y₂O₃, mgO, caO, al ₂O₃,Y₂O₃, the molar ratio of MgO to CaO was 1:0.55:0.15:0.1, the mass ratio of silicon carbide, carbon fiber and auxiliary agent was 1:2:0.05, after heating to 700 ℃, a pressure of 40 MPa/min was applied to the die, the temperature was raised at a temperature raising rate of 30℃to 1800℃and the temperature was maintained for 20 minutes.

Example 10

Substantially the same as in example 4, except that the auxiliary agent was Al ₄Si₃ C, after heating to 700C, a pressure of 40MPa was applied to the die at a rate of 5MPa/min, and the temperature was raised to 1750C at a rate of 30C/min, and the temperature was maintained for 20min.

Comparative example 1

The preparation method comprises the steps of taking carbon fiber short fibers as raw materials, taking phenolic resin as an adhesive, preparing a preform by a mould pressing mode, carbonizing at 900-1000 ℃ for a plurality of hours to a plurality of days, and siliconizing by an RMI process for 3-7 days.

Comparative example 2

The method comprises the steps of taking long fibers as raw materials, preparing a 2.5D fiber preform through a needling process, densifying the fiber preform in a CVI or liquid phase impregnation mode, carbonizing the fiber preform at 900-1000 ℃, wherein the CVI densification needs about one week, the liquid phase impregnation densification needs 2-3 days, and then siliconizing the fiber preform through an RMI process, wherein the process usually needs 3-7 days.

Performance detection

1. The relative density (%) and density (g/cm ³) were measured using an archimedes drain valve;

2. measuring the surface Hardness (HV) under the pressure of 1-5 kg according to GB/T16534-2009 method for testing the room temperature hardness of fine ceramics;

3. flexural strength (MPa) was measured according to GB/T6569 fine ceramic flexural strength test method;

the performance test results are shown in the following table:

as can be seen from the above table, the carbon ceramic composite materials prepared in examples 1 to 10 are superior to the carbon ceramic composite materials of comparative examples 1 to 2 in each performance.

As can be seen from the above table and fig. 1 to 5, in the carbon ceramic composite material prepared in example 1, the carbon fibers are uniformly dispersed, are randomly distributed in a non-directional manner, have high density, and have no obvious pores or defects. The carbon ceramic composite material prepared in example 1 has better performance than the carbon ceramic composite materials prepared in other examples.

While the basic concepts have been described above, it will be apparent to those skilled in the art that the foregoing detailed disclosure is by way of example only and is not intended to be limiting. Although not explicitly described herein, various modifications, improvements, and adaptations to the present disclosure may occur to one skilled in the art. Such modifications, improvements, and modifications are intended to be suggested within this specification, and therefore, such modifications, improvements, and modifications are intended to be included within the spirit and scope of the exemplary embodiments of the present invention.

Meanwhile, the specification uses specific words to describe the embodiments of the specification. Reference to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic is associated with at least one embodiment of the present description. Thus, it should be emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various positions in this specification are not necessarily referring to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of the present description may be combined as suitable.

Furthermore, the order in which the elements and sequences are processed, the use of numerical letters, or other designations in the description are not intended to limit the order in which the processes and methods of the description are performed unless explicitly recited in the claims. While certain presently useful inventive embodiments have been discussed in the foregoing disclosure, by way of various examples, it is to be understood that such details are merely illustrative and that the appended claims are not limited to the disclosed embodiments, but, on the contrary, are intended to cover all modifications and equivalent arrangements included within the spirit and scope of the embodiments of the present disclosure.

Likewise, it should be noted that in order to simplify the presentation disclosed in this specification and thereby aid in understanding one or more inventive embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof. This method of disclosure does not imply that the subject matter of the present description requires more features than are set forth in the claims. Indeed, less than all of the features of a single embodiment disclosed above.

In some embodiments, numbers describing the components, number of attributes are used, it being understood that such numbers being used in the description of embodiments are modified in some examples by the modifier "about," approximately, "or" substantially. Unless otherwise indicated, "about," "approximately," or "substantially" indicate that the number allows for a 20% variation. Accordingly, in some embodiments, numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties sought to be obtained by the individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and employ a method for preserving the general number of digits. Although the numerical ranges and parameters set forth herein are approximations that may be employed in some embodiments to confirm the breadth of the range, in particular embodiments, the setting of such numerical values is as precise as possible.

Each patent, patent application publication, and other material, such as articles, books, specifications, publications, documents, etc., referred to in this specification is incorporated herein by reference in its entirety. Except for application history documents that are inconsistent or conflicting with the content of this specification, documents that are currently or later attached to this specification in which the broadest scope of the claims to this specification is limited are also. It is noted that, if the description, definition, and/or use of a term in an attached material in this specification does not conform to or conflict with what is described in this specification, the description, definition, and/or use of the term in this specification controls.

Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments of this specification. Other variations are possible within the scope of this description. Thus, by way of example, and not limitation, alternative configurations of embodiments of the present specification may be considered as consistent with the teachings of the present specification. Accordingly, the embodiments of the present specification are not limited to only the embodiments explicitly described and depicted in the present specification.

Claims

1. A carbon-ceramic brake disc, characterized in that the carbon-ceramic brake disc is made of a carbon-ceramic composite material, and the preparation method of the carbon-ceramic composite material comprises the following steps:

The silicon carbide, carbon fiber and additive are uniformly mixed to obtain a carbon ceramic preformed powder, wherein the mass ratio of the silicon carbide, carbon fiber and additive is 1: (0.5-2): (0.05-0.1);

The auxiliary agent is selected from at least one of B ₄ C and a metal oxide mixture; the metal oxide mixture is a mixture of Al ₂ O ₃ and Y ₂ O ₃ or a mixture of Al ₂ O ₃ , Y ₂ O ₃ , MgO and CaO;

Placing the carbon ceramic preformed powder in a mold of a direct current rapid sintering device, and applying a first preparation operation to obtain a sample to be sintered;

Starting the heating system of the DC rapid sintering device, gradually increasing the DC current to heat, and after heating to the first temperature, applying a second preparation operation to the sample to be sintered, continuing to increase the DC current, and then gradually raising the temperature to the second temperature, and holding the temperature for a period of time; the second preparation operation includes: gradually applying pressure to the mold at a pressure increase rate of 1MPa/min-10MPa/min to a pressure of 30MPa-50MPa; the second temperature range is 1600°C-2100°C; the heating rate for gradually raising the temperature to the second temperature is 10°C/min-50°C/min; and the holding time is 20min-2h;

The heating system is turned off and the mixture is cooled naturally to obtain a carbon-ceramic composite material.

2. The carbon-ceramic brake disc according to claim 1, wherein the first preparation operation comprises: selecting a mold of appropriate size, insulating the interior with graphite paper, loading the carbon-ceramic prefabricated powder into the mold, applying a pressure of 1 MPa-5 MPa to pre-compact it, and wrapping it with thermally insulating carbon felt.

3. The carbon-ceramic brake disc according to claim 1, wherein the length of the carbon fiber is 5 mm to 30 mm.

4 . The carbon-ceramic brake disc according to claim 1 , wherein the first temperature is 700° C. and the heating rate is 50° C./min-100° C./min.