High-temperature self-healing ceramic matrix composite material and preparation method thereof

Abstract

The invention belongs to the technical field of ceramic-based composite materials, and particularly relates to a high-temperature self-healing ceramic-based composite material and a preparation method thereof.The surface of metal powder is coated with a compact coating, so that metal can be prevented from being oxidized and flowing out in the high-temperature sintering process, the metal content in the composite material is kept, interface bonding between the metal and a ceramic matrix is improved, and the service life of the composite material is prolonged. The density of the finally obtained composite material reaches 98.5% or above, and the maximum bending strength can reach 450-550 MPa. In the high-temperature service process, when the tip of a crack makes contact with metal powder particles coated with the coating, the brittle coating on the surface of the metal powder particles is broken due to stress concentration, molten metal flows out and is driven by capillary force to permeate and fill along the crack, crack healing and fragment gathering are promoted, and therefore the self-healing function is achieved. Through detection, the bending strength recovery rate of the composite material after precracking and high-temperature repair for 1 h is up to 85% or above, and the composite material shows good high-temperature self-healing ability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ceramic matrix composites, and particularly relates to a high-temperature self-healing ceramic matrix composite and a preparation method thereof. BACKGROUND

[0002] Alumina ceramics have high hardness, high wear resistance, high compressive strength, low thermal expansion coefficient, good electrical insulation and excellent chemical stability; silicon carbide ceramics have excellent mechanical properties, including high bending strength, excellent oxidation resistance, good corrosion resistance and wear resistance, both of which are widely used in aerospace, mechanical manufacturing, biological medicine and armor protection fields. However, the inherent brittleness greatly limits the further application of the above-mentioned ceramics. In order to improve the toughness of the above-mentioned two kinds of ceramics, fibers, whiskers, heterogeneous particles and the like are usually used for toughening treatment. However, the preparation process of the fiber / whisker toughened ceramic matrix composite is complex, the cost is high, and due to the harsh service environment, the intrinsic brittleness of the material is easy to cause crack initiation and irreversible expansion, thereby reducing the service life and safety of the composite material.

[0003] In the prior art, self-healing ceramic matrix composites introduce boron-containing elements, titanium diboride and the like as healing agents to generate glass phase by oxidation at high temperature to fill cracks, but such methods have the following disadvantages: 1) high healing temperature: it needs to rely on high-temperature oxidation reaction (usually > 1200℃), and the healing agent has a low flow rate, which limits the healing efficiency; 2) uneven distribution of healing agent: the healing agent is easy to agglomerate, and local excessive introduction may damage the mechanical properties of the material; 3) limited single healing capacity: the healing product is difficult to repeatedly repair new cracks. In recent years, a self-healing scheme of metal particle filling has been proposed, for example, aluminum / silicon alloy phase melts and flows at high temperature to repair cracks. However, the metal has poor interface bonding with the ceramic matrix, is easy to oxidize and fail, and is easy to volatilize or react with the matrix to generate a brittle phase during sintering, which reduces the density and self-healing capacity of the material.

[0004] Therefore, it is urgent to develop a composite material with high density, excellent high-temperature stability and high-efficiency self-healing capacity, while simplifying the preparation process and reducing the cost. SUMMARY

[0005] In view of the problems in the prior art, the present application provides a high-temperature self-healing ceramic matrix composite material and a preparation method thereof, wherein a dense coating layer is coated on the surface of metal powder to avoid oxidation and melting of the metal during high-temperature sintering, maintain the metal content in the composite material, and improve the interface bonding between the metal and the ceramic matrix, so that the density of the finally obtained composite material is more than 98.5%, and the maximum bending strength can reach 450-550 MPa. During high-temperature service, when the crack tip contacts the metal powder particles coated with the coating layer, the stress concentration causes the brittle coating layer on the surface to break, the molten metal flows out and penetrates along the crack under the driving of capillary force, promotes crack healing and fragment gathering, and thus the self-healing function is realized. The bending strength recovery rate of the composite material after pre-cracking and high-temperature repair for 1 h is as high as more than 85%, and the high-temperature self-healing ability is good, the problems of high healing temperature, uneven distribution of healing agent, poor healing agent / matrix interface bonding and low healing efficiency in the prior art are solved, and the material density and service reliability are improved.

[0006] The specific idea of the present application is that a dense ceramic coating layer is uniformly coated on the surface of metal powder by using a magnetron sputtering process, and the metal powder coated with the ceramic layer is uniformly mixed with ceramic powder by using a ball milling process; then the mixed powder is placed in a mold, and a ceramic matrix composite material with high-temperature self-healing function is obtained by using a spark plasma sintering (SPS) process. The metal powder targeted by the present application is aluminum powder or magnesium powder, wherein when the metal powder is aluminum powder, the corresponding ceramic matrix material is aluminum oxide; and when the metal powder is magnesium powder, the corresponding ceramic matrix material is silicon carbide.

[0007] The present application relates to a more specific preparation method of the high-temperature self-healing ceramic matrix composite material, which specifically comprises the following steps: (1) a dense coating layer is prepared on the surface of metal powder by using a magnetron sputtering process, the particle size of the metal powder is 0.1-20 μm, and the thickness of the finally obtained dense coating layer is 0.3-5 μm.

[0008] (2) the metal powder coated with the dense coating layer and the ceramic powder with the same coating layer material are mixed and placed in a ball milling tank, the particle size of the ceramic powder is 0.05-5 μm, the mass fraction of the metal powder coated with the dense coating layer in the mixture is 3-20%, grinding balls are added to the ball milling tank, the ball-to-material ratio is 2-8:1, and anhydrous ethanol is added to the ball milling tank to cover the materials as a ball milling medium; more preferably, the ball-to-material ratio is 3-6:1.

[0009] (3) fixing the ball milling tank in a ball mill for ball milling mixing treatment, the ball milling rotation speed is 100-500 r / min, the ball milling time is 2-8 h, after the ball milling is completed, the ball milling tank is placed in an oven for drying, the drying temperature is 80-150 ℃, to obtain a mixed material of metal powder / ceramic powder coated with dense coating; further, the ball mill is a three-dimensional planetary vibration ball mill, the ball milling rotation speed is 200-400 r / min, the ball milling time is 3-5 h, and the drying temperature is 90-120 ℃.

[0010] (4) placing the mixed material into a graphite mold and placing it in a spark plasma sintering furnace for sintering treatment under an inert gas atmosphere, the heating rate is 100-300 ℃ / min, the sintering temperature is 1200-2000 ℃, the sintering pressure is 100-300 MPa, the holding time is 10-45 min, after the sintering is completed, the furnace is cooled to room temperature, and then the mold is removed to obtain a ceramic matrix composite material with high-temperature self-healing function; further, the heating rate is 200-300 ℃ / min, the sintering pressure is 175-250 MPa, and the holding time is 20-30 min.

[0011] Preferably, when the metal particles in step (1) are magnesium powder or aluminum powder respectively, the corresponding target materials used are high-purity aluminum and high-purity silicon respectively, and the purity of both is above 99.99%, and finally dense alumina and silicon carbide coating layers are obtained respectively. Further, the particle diameter of the magnesium powder or aluminum powder is 0.5-5 μm.

[0012] When the thickness of the coating layer in the composite material is less than 0.3 μm, the coating layer is difficult to densify, and cannot effectively prevent metal oxidation and high-temperature melting and flowing out; and when the thickness is greater than 5 μm, the magnetron sputtering coating efficiency will be greatly reduced. If the content of the metal powder coated with a dense coating in the mixture in step (2) is too low, it cannot effectively fill the cracks, resulting in limited self-healing ability of the composite material; if the content is too high, the ceramic matrix accounts for a low proportion, resulting in poor comprehensive mechanical properties of the composite material.

[0013] Preferably, the ceramic powder is alumina ceramic powder or silicon carbide ceramic powder, and the particle diameter is 0.1-3 μm. The mass fraction of the metal powder coated with a dense coating in the mixture in step (2) is 5-15%.

[0014] When the coating layer material is alumina ceramic powder, the sintering temperature in step (4) is 1200-1700 ℃, and further preferably 1350-1550 ℃.

[0015] When the cladding layer material is silicon carbide ceramic powder, B4C powder and carbon black powder are added as sintering aids in step (2), and the content of the added B4C powder is 3% to 15% and the content of the added carbon black powder is 5% to 15% according to the weight of the silicon carbide ceramic powder. The sintering temperature in step (4) is 1500 to 2000°C.

[0016] More preferably, the mass fraction of the added B4C powder is 5% to 10% and the mass fraction of the added carbon black powder is 8% to 13% according to the weight of the silicon carbide ceramic powder, and the sintering temperature in step (4) is 1700 to 1850°C.

[0017] The inventors also claim the high-temperature self-healing ceramic matrix composite material obtained by the above preparation method.

[0018] ‌Compared with the prior art, the present application has the following beneficial effects: (1) The high-temperature self-healing ceramic matrix composite material provided by the present application can prevent oxidation of the metal during sintering, effectively avoid the molten metal from flowing out when the metal is sintered at a temperature much higher than its melting point, and thus maintain the metal content in the composite material, and also improve the interface bonding between the metal and the ceramic matrix.

[0019] (2) When the crack extends to the inside of the composite material and the tip contacts the metal powder particles coated with the ceramic material, the stress concentration causes the brittle ceramic material coating to break. Since the melting point of the metal is low, the molten metal flows out and penetrates along the crack under the driving force of capillary force, and then cools and solidifies, realizing crack healing and fragment gathering. At the same time, the metal in the composite material can be repaired multiple times by re-melting after filling, prolonging the service life of the material.

[0020] (3) The sintering method used in the present application is a spark plasma sintering process, which is different from conventional hot-pressing sintering. The spark plasma sintering process has a fast heating rate, which can greatly shorten the sintering time and improve the sintering efficiency. At the same time, the low-temperature and high-pressure sintering mode can effectively prevent the oxidation and evaporation of the metal caused by excessively high sintering temperature.

[0021] (4) The ceramic matrix composite material prepared by the present application has a density of more than 98.5% and a maximum bending strength of 450-550MPa. At the same time, the bending strength recovery rate of the composite material after pre-cracking and high-temperature repair for 1h is as high as more than 85%, showing good high-temperature self-healing ability. DETAILED DESCRIPTION

[0022] The technical solutions of the present application will be further described in detail below with reference to the embodiments. Obviously, the embodiments described here are only used to explain the present application, but the present application is not limited to these embodiments.

[0023] In the following examples: (1) Density testing equipment: JA2003 electronic balance.

[0024] (2) The bending strength is measured by using an electronic universal material testing machine (INSTRON5985, USA) according to GB / T 6569-2006 “Fine Ceramic Bending Strength Test Method”.

[0025] (3) The crack is pre-prepared by using the Vickers indentation method, and then the sample is self-healed at 700℃ in a muffle furnace for 1h and cooled to room temperature. The bending strength of the repaired sample is measured, and the self-repairing rate of the mechanical properties of the material is calculated.

[0026] Embodiment 1: A high-temperature self-healing alumina ceramic matrix composite material and a preparation method thereof, and the specific steps are as follows: (1) A dense alumina coating layer is prepared on the surface of the metal aluminum powder by using a magnetron sputtering process. The particle diameter of the metal aluminum powder is 0.1μm, and the purity of the high-purity aluminum used as the target material is more than 99.99%. The specific steps are as follows: First, the aluminum powder is vacuum dried at 120℃ for 2h and ultrasonically dispersed for 30min to ensure that the surface is clean and free of agglomeration. Then, high-purity argon and oxygen are introduced as sputtering gas and reaction gas respectively under a base vacuum degree of 5×10 -3 Pa, the argon-oxygen flow ratio is 2:1, the radio frequency power is set to 200W, the target-substrate distance is 60μm, and the sputtering time is 40min. During the sputtering process, the powder is continuously stirred by a vibrating fluidization device to ensure uniform deposition of sputtered particles in all directions. Finally, the metal aluminum powder with a dense alumina coating layer is obtained, and the thickness of the dense alumina coating layer is 0.3μm; (2) The metal aluminum powder with a dense alumina coating layer is mixed with alumina ceramic powder and placed in a ball milling jar. The particle diameter of the alumina ceramic powder is 0.05μm, and the mass fraction of the metal aluminum powder with a dense alumina coating layer in the mixture is 3%. Alumina balls are added to the ball milling jar, and the ball-to-material ratio is 2:1. Anhydrous ethanol is added to the ball milling jar to cover the material as a ball milling medium; (3) The ball milling jar is fixed in a three-dimensional planetary vibration ball mill for ball milling and mixing treatment. The ball milling speed is 100r / min, and the ball milling time is 8h. After the ball milling is completed, the ball milling jar is placed in an oven for drying. The drying temperature is 80℃, and a uniformly mixed metal aluminum powder / alumina ceramic powder mixture with a dense alumina coating layer is obtained. (4) Put the mixed materials into a graphite mold and place it in a spark plasma sintering furnace for sintering treatment under an inert gas atmosphere, with a heating rate of 200℃ / min, a sintering temperature of 1200℃, a sintering pressure of 300MPa, and a holding time of 45min, and then cool it to room temperature in the furnace after sintering, and finally demold to obtain an alumina ceramic matrix composite material with high-temperature self-healing function, wherein the metal aluminum powder coated with a dense alumina coating layer is uniformly distributed in the alumina ceramic matrix.

[0027] The obtained high-temperature self-healing alumina ceramic matrix composite material has a density of 99.3%, a bending strength of 445MPa, and a bending strength of 421MPa after pre-cracking and repairing at 700℃ for 1h, with a mechanical property self-repairing rate of 87%, showing good high-temperature self-healing ability.

[0028] Example 2: A high-temperature self-healing alumina ceramic matrix composite material and a preparation method thereof, the specific steps are as follows: (1) Use the same magnetron sputtering process as in Example 1 to prepare a dense alumina coating layer on the surface of the metal aluminum powder, the particle diameter of the metal aluminum powder is 20μm, the purity of the high-purity aluminum used as the target material is more than 99.99%, and the sputtering time is 500min, finally obtaining metal aluminum powder coated with a dense coating layer, wherein the thickness of the dense alumina coating layer is 5μm; (2) Put the metal aluminum powder coated with a dense alumina coating layer and the alumina ceramic powder into a ball mill jar, the particle diameter of the alumina ceramic powder is 5μm, the mass fraction of the metal aluminum powder coated with a dense alumina coating layer in the mixture is 20%, add alumina balls to the ball mill jar, the ball-to-material ratio is 8:1, and add anhydrous ethanol to the ball mill jar to cover the materials as the ball milling medium; (3) Fix the ball mill jar in a three-dimensional planetary ball mill for ball milling and mixing treatment, the ball milling speed is 500r / min, and the ball milling time is 2h, after ball milling, place the ball mill jar in an oven for drying, the drying temperature is 150℃, and finally obtain a mixed material of metal aluminum powder coated with a dense alumina coating layer and alumina ceramic powder; (4) Put the mixed materials into a graphite mold and place it in a spark plasma sintering furnace for sintering treatment under an inert gas atmosphere, with a heating rate of 300℃ / min, a sintering temperature of 1700℃, a sintering pressure of 100MPa, and a holding time of 10min, and then cool it to room temperature in the furnace after sintering, and finally demold to obtain an alumina ceramic matrix composite material with high-temperature self-healing function.

[0029] The obtained high-temperature self-healing alumina ceramic matrix composite has a density of 99.0%, a bending strength of 450 MPa, and a bending strength of about 210 MPa after pre-cracking and repairing at 700 DEG C for 1h, which is increased to 405 MPa, and a mechanical property self-repairing rate of 93%, which shows good high-temperature self-healing ability.

[0030] Example 3 A high-temperature self-healing alumina ceramic matrix composite and a preparation method thereof, and the specific steps are as follows: (1) A dense alumina coating layer is prepared on the surface of the metal aluminum powder by using the same magnetron sputtering process as in Example 1, the particle diameter of the metal aluminum powder is 0.5 μm, high-purity aluminum is used as the target material, the purity is more than 99.99%, the sputtering time is 60 min, and the thickness of the dense alumina coating layer in the metal aluminum powder coated with the dense alumina coating layer is 0.5 μm; (2) The metal aluminum powder coated with the dense alumina coating layer is mixed with the alumina ceramic powder and placed in a ball mill jar, the particle diameter of the alumina ceramic powder is 0.1 μm, the mass fraction of the metal aluminum powder coated with the dense alumina coating layer in the mixture is 5%, alumina balls are added to the ball mill jar, the ball-to-material ratio is 3:1, and anhydrous ethanol is added to the ball mill jar to cover the materials as a ball milling medium; (3) The ball mill jar is fixed in a three-dimensional planetary vibration ball mill for ball milling and mixing treatment, the ball milling speed is 200 r / min, the ball milling time is 5 h, after the ball milling is completed, the ball mill jar is placed in an oven for drying, the drying temperature is 90 DEG C, and a mixed material of the metal aluminum powder coated with the dense alumina coating layer and the alumina ceramic powder is obtained; (4) The mixed material is placed in a graphite mold and placed in a spark plasma sintering furnace for sintering treatment in an inert gas atmosphere, the heating rate is 100 DEG C / min, the sintering temperature is 1350 DEG C, the sintering pressure is 250 MPa, the holding time is 30 min, and the sintering is completed after the furnace is cooled to room temperature, and then the alumina ceramic matrix composite with high-temperature self-healing function is obtained after demolding.

[0031] The obtained high-temperature self-healing alumina ceramic matrix composite has a density of 99.5%, a bending strength of 435 MPa, and a bending strength of about 215 MPa after pre-cracking and repairing at 700 DEG C for 1h, which is increased to 405 MPa, and a mechanical property self-repairing rate of 88%, which shows good high-temperature self-healing ability.

[0032] Example 4 A high-temperature self-healing alumina ceramic matrix composite and a preparation method thereof, and the specific steps are as follows: (1) The same magnetron sputtering process as in Example 1 was used to prepare a dense aluminum oxide coating layer on the surface of the metal aluminum powder. The particle diameter of the metal aluminum powder was 5 μm, high-purity aluminum was used as the target material, the purity was more than 99.99%, and the sputtering time was 400 min. The thickness of the dense aluminum oxide coating layer in the metal aluminum powder coated with a dense aluminum oxide coating layer was 3 μm. (2) The metal aluminum powder coated with a dense aluminum oxide coating layer and the aluminum oxide ceramic powder were mixed and placed in a ball milling tank. The particle diameter of the aluminum oxide ceramic powder was 3 μm, the mass fraction of the metal aluminum powder coated with a dense aluminum oxide coating layer in the mixture was 15%, aluminum oxide balls were added to the ball milling tank, the ball-to-material ratio was 6:1, and anhydrous ethanol was added to the ball milling tank to cover the material as a ball milling medium; (3) The ball milling tank was fixed in a three-dimensional planetary vibration ball mill for ball milling and mixing treatment. The ball milling speed was 400 r / min, and the ball milling time was 3 h. After ball milling, the ball milling tank was placed in an oven for drying. The drying temperature was 120°C. A uniformly mixed metal aluminum powder / aluminum oxide ceramic powder mixture coated with a dense aluminum oxide coating layer was obtained. (4) The mixture was placed in a graphite mold and placed in a spark plasma sintering furnace for sintering treatment in an inert gas atmosphere. The heating rate was 200°C / min, the sintering temperature was 1550°C, the sintering pressure was 175 MPa, the holding time was 20 min, and the sintering was completed after the furnace was cooled to room temperature. The aluminum oxide ceramic-based composite material with high-temperature self-healing function was obtained after demolding.

[0033] The obtained high-temperature self-healing aluminum oxide ceramic-based composite material had a density of 99.1%, a bending strength of 450 MPa, and a bending strength of about 210 MPa after pre-cracking and high-temperature repair at 700°C for 1 h, which increased to 405 MPa. The self-repair rate of the mechanical properties was 93%, and the material showed good high-temperature self-healing ability.

[0034] Comparative Example 1 An aluminum oxide ceramic-based composite material and a preparation method thereof, the specific steps are as follows: The difference from Example 1 is that the thickness of the aluminum oxide coating layer on the surface of the metal aluminum powder in step (1) is 0.03 μm. The aluminum oxide ceramic-based composite material prepared in this comparative example 1 had a density of 99.5%, a bending strength of 430 MPa, and a bending strength of about 205 MPa after pre-cracking and high-temperature repair at 700°C for 1 h, which increased to 240 MPa. The self-repair rate of the mechanical properties was only 17%.

[0035] It can be seen from the comparison of Example 1 and this comparative example that, under the premise of the same conditions of particle size of metal aluminum powder, mass fraction of aluminum powder, ball milling process and sintering process, since the thickness of the alumina coating layer is too small, the alumina coating layer cannot completely cover the aluminum powder particles and is not dense, and cannot effectively prevent oxidation and high-temperature evaporation of the metal during high-temperature sintering, the content of the metal aluminum in the prepared composite material is too low, the self-repairing efficiency of the material's mechanical properties is low, and the high-temperature self-healing ability is poor.

[0036] Comparative Example 2: An alumina ceramic matrix composite material and a preparation method thereof, the specific steps are as follows: The difference from Example 2 is that the mass fraction of the metal aluminum powder coated with the dense alumina coating layer in step (2) is 0.5%; The alumina ceramic matrix composite material prepared in this comparative example 2 has a density of 99.2%, a bending strength of 435 MPa, and a bending strength of about 195 MPa after pre-cracking and high-temperature repair at 700°C for 1 h, which is increased to 210 MPa, and the self-repairing rate of the mechanical properties is only about 7.5%.

[0037] It can be seen from the comparison of Example 2 and this comparative example that, under the premise of the same conditions of particle size of metal aluminum powder, thickness of alumina ceramic coating layer, ball milling process and sintering process, since the mass fraction of the metal aluminum powder in the composite material is too low, the composite material cannot effectively promote crack healing by melting of the aluminum powder during subsequent high-temperature treatment, the self-repairing rate of the mechanical properties of the material is low, and the high-temperature self-healing ability is poor.

[0038] Example 5: A high-temperature self-healing silicon carbide ceramic matrix composite material and a preparation method thereof, the specific steps are as follows: (1) A dense silicon carbide coating layer is prepared on the surface of the metal magnesium powder by a magnetron sputtering process, the particle diameter of the metal magnesium powder used is 0.1 μm, high-purity silicon is used as the target material, and the purity is more than 99.99%, the specific steps are as follows: First, the magnesium powder is vacuum dried at 80°C for 2h and ultrasonically dispersed for 30min to avoid oxidation and agglomeration, then high-purity argon and methane are introduced as sputtering gas and reaction gas respectively under a base vacuum degree of 5×10 -3 Pa, the flow ratio of argon / methane is 3:1, the radio frequency power is set to 80W, the target-substrate distance is 100μm, and the sputtering time is 180min. During the sputtering process, the powder is continuously stirred by a vibration fluidization device to ensure uniform deposition of the sputtered particles in all directions, and finally the metal magnesium powder with a dense silicon carbide coating layer on the surface is obtained, and the thickness of the dense silicon carbide coating layer is 0.3μm; (2) Put the magnesium powder coated with dense silicon carbide coating and silicon carbide ceramic powder into a ball mill tank, the particle size of the silicon carbide ceramic powder is 0.05 μm, the mass fraction of the magnesium powder coated with dense silicon carbide coating in the mixture is 3%, and B4C powder and carbon black powder are added as sintering aids, wherein the content of the added B4C powder is 3wt%, and the content of the carbon black powder is 5wt% (based on the weight of the silicon carbide ceramic powder), silicon carbide balls are added to the ball mill tank, the ball-to-material ratio is 2:1, and anhydrous ethanol is added to the ball mill tank to submerge the materials as a ball milling medium; (3) Fix the ball mill tank in a three-dimensional planetary vibration ball mill for ball milling and mixing treatment, the ball milling speed is 100 r / min, the ball milling time is 8 h, after the ball milling is completed, the ball mill tank is placed in an oven for drying, the drying temperature is 80℃, and a uniformly mixed magnesium powder coated with dense silicon carbide coating / silicon carbide ceramic powder mixture is obtained; (4) Put the mixture into a graphite mold and place it in a spark plasma sintering furnace for sintering treatment in an inert gas atmosphere, the heating rate is 200℃ / min, the sintering temperature is 2000℃, the sintering pressure is 300 MPa, the holding time is 45 min, and the sintering is completed after the furnace is cooled to room temperature, and then the mold is removed to obtain a silicon carbide ceramic-based composite material with high-temperature self-healing function, wherein the magnesium powder coated with a dense silicon carbide coating on the surface is uniformly distributed in the silicon carbide ceramic matrix.

[0039] The obtained high-temperature self-healing silicon carbide ceramic-based composite material has a density of 99.3%, a bending strength of 535 MPa, and a bending strength of about 275 MPa after pre-cracking and repairing at 700℃ for 1 h, which is increased to 508 MPa, and the mechanical property self-repairing rate is 85%, showing good high-temperature self-healing ability.

[0040] Example 6 A high-temperature self-healing silicon carbide ceramic-based composite material and a preparation method thereof, the specific steps are as follows: (1) A dense silicon carbide coating is prepared on the surface of the magnesium powder by using the same magnetron sputtering process as in Example 5, the particle diameter of the magnesium powder is 20 μm, high-purity silicon is used as the target material, the purity is more than 99.99%, the sputtering time is 1200 min, and the thickness of the final dense silicon carbide coating is 5 μm; (2) Put the magnesium powder coated with dense silicon carbide and silicon carbide ceramic powder into a ball mill tank, the particle size of the silicon carbide ceramic powder is 5 μm, the mass fraction of the magnesium powder coated with dense silicon carbide in the mixture is 20%, and B4C powder and carbon black powder are added as sintering aids, wherein the content of the added B4C powder is 15 wt%, and the content of the carbon black powder is 15 wt% (based on the weight of the silicon carbide ceramic powder), silicon carbide balls are added to the ball mill tank, the ball-to-material ratio is 8:1, and anhydrous ethanol is added to the ball mill tank to cover the material as a ball milling medium; (3) Fix the ball mill tank in a three-dimensional planetary vibration ball mill for ball milling and mixing, the ball milling speed is 500 r / min, the ball milling time is 2 h, after the ball milling is completed, the ball mill tank is placed in an oven for drying, the drying temperature is 150°C, and a uniformly mixed magnesium powder coated with dense silicon carbide / silicon carbide ceramic powder mixture is obtained; (4) Put the mixture into a graphite mold and place it in a spark plasma sintering furnace for sintering treatment in an inert gas atmosphere, the heating rate is 300°C / min, the sintering temperature is 1500°C, the sintering pressure is 100 MPa, the holding time is 10 min, and the sintering is completed after the furnace is cooled to room temperature, and then the mold is removed to obtain a silicon carbide ceramic matrix composite material with high-temperature self-healing function.

[0041] The obtained high-temperature self-healing silicon carbide ceramic matrix composite material has a density of 99.0%, a bending strength of 540 MPa, and a bending strength of about 260 MPa after pre-cracking and repairing at 700°C for 1 h, which is increased to 500 MPa, and the mechanical property self-repairing rate is 92%, showing good high-temperature self-healing ability.

[0042] Example 7 A high-temperature self-healing silicon carbide ceramic matrix composite material and a preparation method thereof, the specific steps are as follows: (1) A dense silicon carbide coating layer is prepared on the surface of the magnesium powder by using the same magnetron sputtering process as in Example 5, the particle diameter of the magnesium powder is 0.5 μm, high-purity silicon is used as the target material, the purity is more than 99.99%, and the sputtering time is 900 min, and finally a dense silicon carbide coating layer with a thickness of 4 μm is obtained; (2) Put the magnesium powder coated with dense silicon carbide and silicon carbide ceramic powder into a ball mill tank, the particle size of the silicon carbide ceramic powder is 0.1 μm, the mass fraction of the magnesium powder coated with dense silicon carbide in the mixture is 5%, and B4C powder and carbon black powder are added as sintering aids, wherein the content of the added B4C powder is 10 wt%, and the content of the carbon black powder is 12 wt% (based on the weight of the silicon carbide ceramic powder), silicon carbide balls are added to the ball mill tank, the ball-to-material ratio is 3:1, and anhydrous ethanol is added to the ball mill tank to cover the material as a ball milling medium; (3) The ball mill tank is fixed in a three-dimensional planetary vibration ball mill for ball milling mixing treatment, the ball milling rotation speed is 200 r / min, the ball milling time is 5 h, after the ball milling is completed, the ball mill tank is placed in an oven for drying, the drying temperature is 90 DEG C, and a mixed magnesium powder / silicon carbide ceramic powder material with uniformly mixed dense silicon carbide coating is obtained; (4) The mixed material is placed into a graphite mold and placed in a spark plasma sintering furnace for sintering treatment in an inert gas atmosphere, the heating rate is 100 DEG C / min, the sintering temperature is 1700 DEG C, the sintering pressure is 250 MPa, the holding time is 30 min, after the sintering is completed, the furnace is cooled to room temperature, and then the mold is demolded to obtain a silicon carbide ceramic matrix composite material with high-temperature self-healing function.

[0043] The obtained high-temperature self-healing silicon carbide ceramic matrix composite material has a density of 99.5%, a bending strength of 550 MPa, and a bending strength of about 280 MPa after pre-cracking and repairing at 700 DEG C for 1 h, which is increased to 525 MPa, and the mechanical property self-repairing rate is 87.5%, which shows good high-temperature self-healing ability.

[0044] Example 8 A high-temperature self-healing silicon carbide ceramic matrix composite material and a preparation method thereof, the specific steps are as follows: (1) A dense silicon carbide coating is prepared on the surface of the magnesium powder by using the same magnetron sputtering process as in Example 5, the particle diameter of the magnesium powder is 5 μm, high-purity silicon is used as the target material, the purity is more than 99.99%, the sputtering time is 600 min, and the thickness of the final dense silicon carbide coating is 3 μm; (2) The magnesium powder coated with the dense silicon carbide coating and the silicon carbide ceramic powder are mixed and placed into a ball mill tank, the particle diameter of the silicon carbide ceramic powder is 3 μm, the mass fraction of the magnesium powder coated with the dense silicon carbide coating in the mixture is 15%, B4C powder and carbon black powder are added as sintering aids, the content of the added B4C powder is 5 wt%, the content of the added carbon black powder is 8 wt% (based on the weight of the silicon carbide ceramic powder), silicon carbide balls are added into the ball mill tank, the ball-to-material ratio is 6:1, and anhydrous ethanol is added into the ball mill tank to cover the materials as a ball milling medium; (3) The ball mill tank is fixed in a three-dimensional planetary vibration ball mill for ball milling mixing treatment, the ball milling rotation speed is 200 r / min, the ball milling time is 5 h, after the ball milling is completed, the ball mill tank is placed in an oven for drying, the drying temperature is 90 DEG C, and a mixed magnesium powder / silicon carbide ceramic powder material with uniformly mixed dense silicon carbide coating is obtained; (4) Put the mixed materials into a graphite mold and place it in a spark plasma sintering furnace for sintering treatment under an inert gas atmosphere, with a heating rate of 200℃ / min, a sintering temperature of 1850℃, a sintering pressure of 175MPa, and a holding time of 20min, and then cool to room temperature in the furnace, and finally demold to obtain a silicon carbide ceramic matrix composite material with high-temperature self-healing function.

[0045] The obtained high-temperature self-healing silicon carbide ceramic matrix composite material has a density of 99.1%, a bending strength of 545MPa, and a bending strength of about 275MPa after pre-cracking and high-temperature repair at 700℃ for 1h, which is increased to 530MPa, and a mechanical property self-repairing rate of 92.7%, showing good high-temperature self-healing ability.

[0046] Comparative Example 3 A silicon carbide ceramic matrix composite material and a preparation method thereof, the specific steps are as follows: The difference from Example 5 is that the thickness of the silicon carbide coating layer on the surface of the magnesium powder in step (1) is 0.03μm. The silicon carbide ceramic matrix composite material prepared in this comparative example 3 has a density of 98.6%, a bending strength of 530MPa, and a bending strength of about 270MPa after pre-cracking and high-temperature repair at 700℃ for 1h, which is increased to 285MPa, and a mechanical property self-repairing rate of only 5.5%.

[0047] As can be seen from the comparison between Example 5 and this comparative example, under the same conditions of magnesium powder particle size, magnesium powder mass fraction, ball milling process and sintering process, etc., due to the too small thickness of the silicon carbide coating layer, the magnesium powder particles cannot be completely coated, the coating layer is not dense, and the oxidation and high-temperature evaporation of the metal during high-temperature sintering cannot be effectively prevented, resulting in too low content of magnesium in the prepared composite material, which cannot play a self-repairing effect in the subsequent high-temperature treatment process, and the mechanical property self-repairing rate of the material is low, and the high-temperature self-healing ability is poor.

[0048] Comparative Example 4 A silicon carbide ceramic matrix composite material and a preparation method thereof, the specific steps are as follows: The difference from Example 6 is that the mass fraction of the coated dense silicon carbide coating layer of the magnesium powder in step (2) is 0.5%. The silicon carbide ceramic matrix composite material prepared in this comparative example 4 has a density of 99.1%, a bending strength of 545MPa, and a bending strength of about 270MPa after pre-cracking and high-temperature repair at 700℃ for 1h, which is increased to 290MPa, and a mechanical property self-repairing rate of only about 7.4%.

[0049] It can be seen from the comparison of the example 6 with the present comparative example that, under the premise of the same conditions of the particle size of the magnesium powder, the thickness of the silicon carbide ceramic coating layer, the ball milling process and the sintering process, due to the too low mass fraction of the magnesium powder in the composite material, the composite material cannot effectively pass through the magnesium powder melting to promote crack healing in the subsequent high temperature treatment process, the self-repairing rate of the mechanical property of the material is low, and the high temperature self-healing ability is poor.

[0050] The present application includes but is not limited to the above examples, any equivalent replacement or partial improvement made under the spirit and principle of the present application will be considered within the protection scope of the present application.

Claims

1. A method for producing a high-temperature self-healing ceramic matrix composite material, characterized by, Specifically comprising the following steps: (1) A dense coating layer is prepared on the surface of metal powder by magnetron sputtering process, the particle size of the metal powder used is 0.1-20 μm, and finally a dense coating layer with a thickness of 0.3-5 μm is obtained; (2) The metal powder with a dense coating layer on the surface is mixed with ceramic powder of the same coating layer material in a ball mill tank, the particle size of the ceramic powder is 0.05-5 μm, the mass fraction of the metal powder with a dense coating layer on the surface in the mixture is 3-20%, grinding balls are added in the ball mill tank, the ball-to-material ratio is 2-8:1, and anhydrous ethanol is added in the ball mill tank to cover the material as a ball milling medium; (3) The ball mill tank is fixed in a ball mill for ball milling and mixing treatment, the ball milling speed is 100-500 r / min, the ball milling time is 2-8 h, and after the ball milling is completed, the ball mill tank is placed in an oven for drying, the drying temperature is 80-150 ℃, and a mixed material of metal powder / ceramic powder with a dense coating layer is obtained; (4) The mixed material is placed in a graphite mold and placed in a spark plasma sintering furnace for sintering treatment in an inert gas atmosphere, the heating rate is 100-300 ℃ / min, the sintering temperature is 1200-2000 ℃, the sintering pressure is 100-300 MPa, the holding time is 10-45 min, and after the sintering is completed, the furnace is cooled to room temperature, and then the mold is removed to obtain a ceramic matrix composite material with high-temperature self-healing function.

2. The method for preparing the high-temperature self-healing ceramic matrix composite material according to claim 1, characterized in that, In step (1), when the metal particles are magnesium powder or aluminum powder, the corresponding target materials are high-purity aluminum and high-purity silicon, respectively, and the purity of each is above 99.99%, and finally a dense alumina coating layer and a dense silicon carbide coating layer are obtained, respectively; in step (1), the particle diameter of the magnesium powder or aluminum powder is 0.5-5 μm, and the surface coating layer has a thickness of 0.5-3 μm.

3. The method for preparing the high-temperature self-healing ceramic matrix composite material according to claim 1, characterized in that, In step (2), the particle size of the ceramic powder is 0.1-3 μm; the mass fraction of the metal powder with a dense coating layer on the surface in the mixture is 5-15%; and the ball-to-material ratio is 3-6:

1.

4. The method for preparing the high-temperature self-healing ceramic matrix composite material according to claim 1, characterized in that, In step (3), the ball mill is a three-dimensional planetary vibration ball mill, the ball milling speed is 200-400 r / min, the ball milling time is 3-5 h, and the drying temperature is 90-120 ℃.

5. The method for preparing the high-temperature self-healing ceramic matrix composite material according to claim 1, characterized in that, In step (4), the heating rate is 200-300 ℃ / min, the sintering pressure is 175-250 MPa, and the holding time is 20-30 min.

6. The method for preparing the high-temperature self-healing ceramic matrix composite material according to claim 2, characterized in that, When the coating layer material is alumina ceramic powder, the sintering temperature in step (4) is 1200-1700 ℃.

7. The method for preparing the high-temperature self-healing ceramic matrix composite material according to claim 6, characterized in that, When the coating layer material is alumina ceramic powder, the sintering temperature in step (4) is 1350-1550 ℃.

8. The method for preparing the high-temperature self-healing ceramic matrix composite material according to claim 2, characterized in that, When the coating layer material is silicon carbide ceramic powder, B4C powder and carbon black powder are added as sintering aids in step (2), the content of the added B4C powder is 3-15% based on the weight of the silicon carbide ceramic powder, and the content of the added carbon black powder is 5-15%; and the sintering temperature in step (4) is 1500-2000 ℃.

9. The method for preparing the high-temperature self-healing ceramic matrix composite material according to claim 8, characterized in that, According to the weight of the silicon carbide ceramic powder, the mass fraction of the B4C powder is 5%-10%, and the mass fraction of the carbon black powder is 8%-13%, and the sintering temperature in step (4) is 1700-1850 ℃.

10. The high-temperature self-healing ceramic matrix composite obtained by the method according to any one of claims 1-9.