Carbon fiber reinforced ceramic encapsulated heat conducting plate and preparation method thereof

Abstract

The application relates to the technical field of high-thermal-conductivity composite materials, in particular to a carbon-fiber-reinforced ceramic packaging heat-conducting plate and a preparation method thereof. The method comprises the following steps: carbon fibers are modified through nitric acid treatment and methyltrichlorosilane chemical vapor deposition; a three-dimensional orthogonal preform is braided, and a porous framework is formed by melt impregnation of phenolic resin; aluminum nitride powder, graphite, polysilicon boron nitride, ZrB2 powder and titanium powder are mixed to prepare slurry, the slurry is impregnated into the framework, and a green body is obtained after solidification; the green body is kept at 1500 DEG C for 2 hours in an inert atmosphere, densification is realized through TiCN solid solution filling of pores; a conical through hole is formed on the substrate through laser processing, and the through hole is filled with graphene oxide / phenolic resin premix, and the through hole is subjected to heat pressing, solidification, decarburization and pulse chemical vapor deposition densification to form a porous graphene heat-conducting network. The heat-conducting plate prepared through the method has significantly improved thermal conductivity, and the preparation period is greatly shortened, and the heat-conducting plate is suitable for fields such as high-power semiconductor devices.

Description

Technical Field

[0001] This invention relates to the field of high thermal conductivity composite materials technology, specifically to a carbon fiber reinforced ceramic encapsulated heat-conducting plate and its preparation method. Background Technology

[0002] With the rapid development of high-power semiconductor devices, 5G millimeter-wave communication, and aerospace electronic systems, thermal management materials are facing unprecedented performance challenges. Traditional metal packaging materials are insufficient to meet the requirements due to their low upper limit of thermal conductivity and high density, while ceramic matrix composites, although possessing advantages in high-temperature resistance, suffer from three core contradictions:

[0003] Firstly, insufficient intrinsic thermal conductivity of the matrix material leads to performance bottlenecks. Existing technologies, such as the zirconium-silicon-based system in patent CN110028329B, although improving thermal conductivity through graphene modification and multiple impregnation processes, suffer from a significant decrease in vertical thermal conductivity due to the phonon scattering effect at the matrix grain boundaries. Patent CN116283326B uses a composite of a high thermal conductivity graphite core and a carbon fiber encapsulation layer, which partially alleviates thermal expansion mismatch, but the overall vertical thermal conductivity remains low due to the insufficient intrinsic thermal conductivity of the ceramic encapsulation layer, making it difficult to meet the three-dimensional heat dissipation requirements of high-power devices.

[0004] Secondly, the multi-round impregnation densification process is inefficient and damages the matrix. Existing technologies generally require several or even more than ten impregnation-pyrolysis cycles, with each cycle lasting tens of hours. This process not only leads to carbon fiber oxidative degradation and the accumulation of pyrolysis shrinkage stress, forming microcracks, but also makes it difficult to achieve high-density densification due to the porosity rebound effect, ultimately affecting the material's mechanical properties and reliability.

[0005] Third, the structural design lacks directional heat dissipation paths. Traditional homogeneous substrate designs cannot meet the vertical heat dissipation requirements of chips, while machined cylindrical through-holes are prone to substrate chipping, and the weak bonding between the filler and the hole wall leads to high thermal resistance. More seriously, the severe mismatch in thermal expansion coefficients between the metal and ceramic encapsulation layers inevitably leads to interface cracking during thermal cycling, becoming a core defect restricting the application of the material.

[0006] Therefore, developing novel ceramic encapsulation materials that combine high thermal conductivity, short fabrication cycle, and integrated structural and functional properties has become an urgent task. This material needs to overcome the thermal conductivity limitations of traditional silicon carbide substrates, achieve efficient fabrication through a single densification process, and construct a three-dimensional anisotropic thermally conductive network to ultimately solve the thermal management challenges in high-power applications. Summary of the Invention

[0007] Based on the problems existing in the above-mentioned background technology, the present invention proposes a method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate, the steps of which are as follows.

[0008] Step 1: Immerse the carbon fiber in a 5% nitric acid solution and react at 120°C for 4 hours to remove surface impurities. Then wash with deionized water until neutral and dry to obtain clean fiber. Place the clean fiber in a chemical vapor deposition furnace and react with 200 sccm of methyltrichlorosilane under argon atmosphere for 2 hours to obtain surface-modified carbon fiber.

[0009] Step 2: The surface-modified carbon fibers obtained in Step 1 are woven into a three-dimensional orthogonal structure preform, and then filled with phenolic resin using a melt impregnation process to form a porous carbon fiber skeleton, providing a support framework for subsequent matrix composites.

[0010] Step 3: 70wt% aluminum nitride powder and 30wt% graphite are ball-milled and mixed for 2 hours. Polysiloxane with a solid content of 65% is added and stirred evenly to obtain a mixed slurry. 15wt% ZrB2 powder and 0.5wt% titanium powder are added to the mixed slurry and ultrasonically dispersed for 30 minutes to obtain a uniformly dispersed slurry. The porous carbon fiber skeleton prepared in Step 2 is impregnated in the uniformly dispersed slurry for 2 hours and cured at 120℃ for 4 hours to obtain a preform.

[0011] Step 4: Place the preform obtained in Step 3 in a high-temperature furnace, heat it to 1500℃ at 5℃ / min under an inert atmosphere and hold it for 2 hours. The generated TiN and TiC form TiCN solid solution to efficiently fill the pores of the matrix and obtain a densified matrix.

[0012] Step 5: A tapered through-hole is laser-processed along the thickness direction of the densified matrix obtained in Step 4. The tapered through-hole is filled with a premix of graphene oxide and phenolic resin modified with KH-550 silane coupling agent. The mixture is then hot-pressed and cured at 200°C and 2MPa for 1 hour. It is then decarburized in argon at 1400°C for 2 hours to form a porous graphene thermal conductive network. Finally, it is densified by pulsed chemical vapor deposition to obtain the finished heat-conducting plate.

[0013] Preferably, in step 1, the drying temperature is 150°C and the drying time is 2 hours; the chemical vapor deposition furnace is heated from 800°C to 1100°C at a heating rate of 10°C / min in an argon atmosphere, and then 200 sccm of methyltrichlorosilane is introduced.

[0014] Preferably, in step 2, the melt impregnation process involves injecting phenolic resin with a viscosity controlled at 200±20 mPa·s into the pores of the preform at 350℃±10℃ and 1.5MPa pressure, and then curing it in a nitrogen atmosphere at 180℃ for 3 hours.

[0015] Preferably, in step 3, the aluminum nitride powder particle size D 50=0.5μm, the graphite particle size is ≤10μm, the ZrB2 powder particle size is 1-5μm, and the titanium powder particle size is ≤10μm.

[0016] Preferably, in step 4, the inert atmosphere is nitrogen, and the nitrogen partial pressure is ≥90%.

[0017] Preferably, in step 5, the tapered through-hole array is arranged on the machined surface of the substrate, and the machining density of the tapered through-hole is 60-80 holes / cm².

[0018] Preferably, in step 5, the tapered through hole has a top diameter of 50 μm, a bottom diameter of 200 μm, and a taper angle of 30°.

[0019] Preferably, in step 5, the mass ratio of the graphene oxide and phenolic resin premix is ​​3:7, and the parameters of the pulsed chemical vapor deposition are: methane is introduced at a flow rate of 500 sccm at a temperature of 1800℃, the pulse gas supply time is 10s on and 5s off, and the total pulse gas supply time is greater than 1 hour.

[0020] Preferably, the finished heat-conducting plate is prepared by a method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate.

[0021] Compared with the prior art, the beneficial effects of the present invention are: 1) The carbon fiber is modified by nitric acid treatment and chemical vapor deposition, which not only deeply purifies the fiber surface, but also forms a nanoscale modified layer through the reaction of methyltrichlorosilane, which significantly enhances the interfacial bonding strength between the fiber and the aluminum nitride-graphite matrix, thereby breaking through the upper limit of the thermal conductivity of the traditional silicon carbide matrix and improving the thermal conductivity in the vertical direction by more than 40%.

[0022] 2) The unique three-dimensional orthogonal prefabricated structure combined with the conical channel design creates a three-dimensional anisotropic thermal conductivity network. The large diameter design at the top of the conical channel can accommodate more modified graphene oxide premix, while the small diameter structure at the bottom enhances the density of the structure after curing through capillary action. Combined with the hot-press curing process, it forms a low thermal resistance thermal conductivity channel, effectively solving the problems of easy edge breakage and weak interface bonding of traditional cylindrical through holes.

[0023] 3) By synergistically optimizing pulsed chemical vapor deposition and single-round impregnation processes, the densification cycle of traditional multi-round processes is shortened, while avoiding carbon fiber oxidation and degradation caused by multi-round high-temperature treatment. Finally, a structural and functional integrated heat-conducting plate with thermal conductivity, low coefficient of thermal expansion and high bending strength is produced, which is suitable for the stringent requirements of high-efficiency heat dissipation and long-term reliability in cutting-edge fields such as aerospace thermal control components. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1

[0026] A method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate includes the following steps.

[0027] Step 1: Immerse the carbon fiber in a 5% nitric acid solution and react at 120°C for 4 hours to remove surface impurities. Then wash with deionized water until neutral and dry at 150°C for 2 hours to obtain clean fiber. Place the clean fiber in a chemical vapor deposition furnace and heat it from 800°C to 1100°C at a rate of 10°C / min. In an argon atmosphere, introduce 200 sccm of methyltrichlorosilane and react for 2 hours to obtain surface-modified carbon fiber.

[0028] Step 2: The surface-modified carbon fibers obtained in Step 1 are woven into a three-dimensional orthogonal structure preform, and then phenolic resin is filled into it using a melt impregnation process to form a porous carbon fiber skeleton. The melt impregnation process parameters are as follows: at 350℃ and 1.5MPa pressure, phenolic resin with a viscosity controlled at 200 mPa·s is injected into the pores of the preform, and then cured in a nitrogen atmosphere at 180℃ for 3 hours to provide a supporting framework for subsequent matrix composite.

[0029] Step 3: Add 70wt% aluminum nitride powder (particle size D) 50 =0.5μm) and 30wt% graphite (particle size 10μm) were ball-milled for 2 hours. Polysiloxane with a solid content of 65% was added and stirred evenly to obtain a mixed slurry. 15wt% ZrB2 powder (particle size 5μm) and 0.5wt% titanium powder (particle size 10μm) were added to the mixed slurry. After ultrasonic dispersion for 30 minutes, a uniformly dispersed slurry was obtained. The porous carbon fiber skeleton prepared in step 2 was impregnated in the uniformly dispersed slurry for 2 hours and cured at 120℃ for 4 hours to obtain a preformed voxel.

[0030] Step 4: Place the preform obtained in Step 3 in a high-temperature furnace, heat it to 1500℃ at 5℃ / min under an inert nitrogen atmosphere and hold it for 2 hours. The generated TiN and TiC form TiCN solid solution to efficiently fill the pores of the matrix and obtain a densified matrix.

[0031] Step 5: In the thickness direction of the densified matrix obtained in Step 4, a tapered through-hole is laser-processed. The channels of the tapered through-hole are filled with a premix of graphene oxide and phenolic resin modified with KH-550 silane coupling agent. The mass ratio of graphene oxide to phenolic resin premix is ​​3:7. The mixture is hot-pressed and cured at 200℃ and 2MPa for 1 hour. Then, it is decarburized in argon at 1400℃ for 2 hours to form a porous graphene thermally conductive network. Finally, it is densified by pulsed chemical vapor deposition. The parameters of pulsed chemical vapor deposition are: methane flow rate of 500 sccm at 1800℃, pulse gas supply time of 10s on and 5s off, and total pulse gas supply time of more than 1 hour to obtain the finished heat-conducting plate.

[0032] The carbon fiber reinforced ceramic encapsulation heat-conducting plate prepared in Example 1 of this invention exhibits significant advantages over traditional ceramic encapsulation heat-conducting plates in terms of thermal conductivity, thermal expansion matching, and mechanical strength through an innovative fabrication process. It utilizes surface-modified carbon fibers to construct a three-dimensional orthogonal preform, combined with aluminum nitride-graphite composite slurry impregnation and tapered through-hole filling, resulting in a vertical thermal conductivity improvement of over 40%. This overcomes the bottleneck of traditional materials having low upper limits of thermal conductivity and difficulty in meeting three-dimensional heat dissipation requirements. Simultaneously, through a single-stage densification process and pulsed chemical vapor deposition technology, the coefficient of thermal expansion is effectively reduced, alleviating the interface cracking problem caused by thermal expansion mismatch with the metal encapsulation layer. Its low thermal expansion characteristics are more suitable for the thermal cycling environment of high-power devices. Furthermore, the optimized melt impregnation and hot-press curing processes avoid carbon fiber oxidation degradation and microcrack formation caused by multiple rounds of high-temperature treatment, significantly improving bending strength and reliability. These improvements make the heat-conducting plate of Example 1 more valuable for applications in fields with stringent thermal management requirements, such as high-power semiconductor packaging.

[0033] Example 2

[0034] A method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate includes the following steps.

[0035] Step 1: Immerse the carbon fiber in a 5% nitric acid solution and react at 120°C for 4 hours to remove surface impurities. Then wash with deionized water until neutral and dry at 150°C for 2 hours to obtain clean fiber. Place the clean fiber in a chemical vapor deposition furnace and heat it from 800°C to 1100°C at a rate of 10°C / min. In an argon atmosphere, introduce 200 sccm of methyltrichlorosilane and react for 2 hours to obtain surface-modified carbon fiber.

[0036] Step 2: The surface-modified carbon fibers obtained in Step 1 are woven into a three-dimensional orthogonal structure preform, and then phenolic resin is filled into it using a melt impregnation process to form a porous carbon fiber skeleton. The melt impregnation process parameters are as follows: at 350℃ and 1.5MPa pressure, phenolic resin with a viscosity controlled at 200 mPa·s is injected into the pores of the preform, and then cured in a nitrogen atmosphere at 180℃ for 3 hours to provide a supporting framework for subsequent matrix composite.

[0037] Step 3: Add 70wt% aluminum nitride powder (particle size D) 50 =0.5μm) and 30wt% graphite (particle size 5μm) were ball-milled for 2 hours. Polysiloxane with a solid content of 65% was added and stirred evenly to obtain a mixed slurry. 15wt% ZrB2 powder (particle size 3μm) and 0.5wt% titanium powder (particle size 5μm) were added to the mixed slurry. After ultrasonic dispersion for 30 minutes, a uniformly dispersed slurry was obtained. The porous carbon fiber skeleton prepared in step 2 was impregnated in the uniformly dispersed slurry for 2 hours and cured at 120℃ for 4 hours to obtain a preformed voxel.

[0038] Step 4: Place the preform obtained in Step 3 in a high-temperature furnace, heat it to 1500℃ at 5℃ / min under an inert nitrogen atmosphere and hold it for 2 hours. The generated TiN and TiC form TiCN solid solution to efficiently fill the pores of the matrix and obtain a densified matrix.

[0039] Step 5: In the thickness direction of the densified matrix obtained in Step 4, a tapered through-hole is laser-processed. The channels of the tapered through-hole are filled with a premix of graphene oxide and phenolic resin modified with KH-550 silane coupling agent. The mass ratio of graphene oxide to phenolic resin premix is ​​3:7. The mixture is hot-pressed and cured at 200℃ and 2MPa for 1 hour. Then, it is decarburized in argon at 1400℃ for 2 hours to form a porous graphene thermally conductive network. Finally, it is densified by pulsed chemical vapor deposition. The parameters of pulsed chemical vapor deposition are: methane flow rate of 500 sccm at 1800℃, pulse gas supply time of 10s on and 5s off, and total pulse gas supply time of more than 1 hour to obtain the finished heat-conducting plate.

[0040] Example 3

[0041] A method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate includes the following steps.

[0042] Step 1: Immerse the carbon fiber in a 5% nitric acid solution and react at 120°C for 4 hours to remove surface impurities. Then wash with deionized water until neutral and dry at 150°C for 2 hours to obtain clean fiber. Place the clean fiber in a chemical vapor deposition furnace and heat it from 800°C to 1100°C at a rate of 10°C / min. In an argon atmosphere, introduce 200 sccm of methyltrichlorosilane and react for 2 hours to obtain surface-modified carbon fiber.

[0043] Step 2: The surface-modified carbon fibers obtained in Step 1 are woven into a three-dimensional orthogonal structure preform, and then phenolic resin is filled into it using a melt impregnation process to form a porous carbon fiber skeleton. The melt impregnation process parameters are as follows: at 340℃ and 1.5MPa pressure, phenolic resin with a viscosity controlled at 180 mPa·s is injected into the pores of the preform, and then cured in a nitrogen atmosphere at 180℃ for 3 hours to provide a supporting framework for subsequent matrix composite.

[0044] Step 3: Add 70wt% aluminum nitride powder (particle size D) 50 =0.5μm) and 30wt% graphite (7μm particle size) were ball-milled for 2 hours. Polysiloxane with a solid content of 65% was added and stirred evenly to obtain a mixed slurry. 15wt% ZrB2 powder (1μm particle size) and 0.5wt% titanium powder (7μm particle size) were added to the mixed slurry. After ultrasonic dispersion for 30 minutes, a uniformly dispersed slurry was obtained. The porous carbon fiber skeleton prepared in step 2 was impregnated in the uniformly dispersed slurry for 2 hours and cured at 120℃ for 4 hours to obtain a preformed voxel.

[0045] Step 4: Place the preform obtained in Step 3 in a high-temperature furnace, heat it to 1500℃ at 5℃ / min under an inert nitrogen atmosphere and hold it for 2 hours. The generated TiN and TiC form TiCN solid solution to efficiently fill the pores of the matrix and obtain a densified matrix.

[0046] Step 5: In the thickness direction of the densified matrix obtained in Step 4, a tapered through-hole is laser-processed. The channels of the tapered through-hole are filled with a premix of graphene oxide and phenolic resin modified with KH-550 silane coupling agent. The mass ratio of graphene oxide to phenolic resin premix is ​​3:7. The mixture is hot-pressed and cured at 200℃ and 2MPa for 1 hour. Then, it is decarburized in argon at 1400℃ for 2 hours to form a porous graphene thermally conductive network. Finally, it is densified by pulsed chemical vapor deposition. The parameters of pulsed chemical vapor deposition are: methane flow rate of 500 sccm at 1800℃, pulse gas supply time of 10s on and 5s off, and total pulse gas supply time of more than 1 hour to obtain the finished heat-conducting plate.

[0047] Example 4

[0048] A method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate includes the following steps.

[0049] Step 1: Immerse the carbon fiber in a 5% nitric acid solution and react at 120°C for 4 hours to remove surface impurities. Then wash with deionized water until neutral and dry at 150°C for 2 hours to obtain clean fiber. Place the clean fiber in a chemical vapor deposition furnace and heat it from 800°C to 1100°C at a rate of 10°C / min. In an argon atmosphere, introduce 200 sccm of methyltrichlorosilane and react for 2 hours to obtain surface-modified carbon fiber.

[0050] Step 2: The surface-modified carbon fibers obtained in Step 1 are woven into a three-dimensional orthogonal structure preform, and then phenolic resin is filled into it using a melt impregnation process to form a porous carbon fiber skeleton. The melt impregnation process parameters are as follows: at 360℃ and 1.5MPa pressure, phenolic resin with a viscosity controlled at 220 mPa·s is injected into the pores of the preform, and then cured in a nitrogen atmosphere at 180℃ for 3 hours to provide a supporting framework for subsequent matrix composite.

[0051] Step 3: Add 70wt% aluminum nitride powder (particle size D) 50 =0.5μm) and 30wt% graphite (particle size 9μm) were ball-milled for 2 hours. Polysiloxane with a solid content of 65% was added and stirred evenly to obtain a mixed slurry. 15wt% ZrB2 powder (particle size 5μm) and 0.5wt% titanium powder (particle size 9μm) were added to the mixed slurry. After ultrasonic dispersion for 30 minutes, a uniformly dispersed slurry was obtained. The porous carbon fiber skeleton prepared in step 2 was impregnated in the uniformly dispersed slurry for 2 hours and cured at 120℃ for 4 hours to obtain a preformed voxel.

[0052] Step 4: Place the preform obtained in Step 3 in a high-temperature furnace, heat it to 1500℃ at 5℃ / min under an inert nitrogen atmosphere and hold it for 2 hours. The generated TiN and TiC form TiCN solid solution to efficiently fill the pores of the matrix and obtain a densified matrix.

[0053] Step 5: In the thickness direction of the densified matrix obtained in Step 4, a tapered through-hole is laser-processed. The channels of the tapered through-hole are filled with a premix of graphene oxide and phenolic resin modified with KH-550 silane coupling agent. The mass ratio of graphene oxide to phenolic resin premix is ​​3:7. The mixture is hot-pressed and cured at 200℃ and 2MPa for 1 hour. Then, it is decarburized in argon at 1400℃ for 2 hours to form a porous graphene thermally conductive network. Finally, it is densified by pulsed chemical vapor deposition. The parameters of pulsed chemical vapor deposition are: methane flow rate of 500 sccm at 1800℃, pulse gas supply time of 10s on and 5s off, and total pulse gas supply time of more than 1 hour to obtain the finished heat-conducting plate.

[0054] Comparative Example 1

[0055] Step 1 of the nitric acid treatment and chemical vapor deposition modification of carbon fiber in Example 1 of the present invention is omitted. Untreated carbon fiber is used directly to weave a preform. The remaining preparation steps are completely consistent with those in Example 1. The results show that there is a weak interface layer between the fiber and the matrix. The interface thermal resistance increases significantly during heat conduction. The final thermal conductivity is reduced by more than 30% compared with Example 1. The bending strength decreases by about 25% due to the increased risk of interface debonding.

[0056] Comparative Example 2

[0057] In step 5 of Example 1, a three-dimensional heat conduction channel in the vertical direction was constructed by laser processing of a tapered through hole and filling it with a premix of graphene oxide and phenolic resin. In Comparative Example 2, the tapered through hole processing step was not performed. The premix of graphene oxide and phenolic resin was directly filled into a flat surface. The remaining preparation steps were completely consistent with those in Example 1. The results showed that the heat conduction network was limited to the planar direction, and the thermal resistance in the vertical direction increased by more than 2 times. Finally, the thermal conductivity in the vertical direction was greatly reduced compared with Example 1, which could not meet the requirements of high-power devices for three-dimensional heat dissipation.

[0058] Comparative Example 3

[0059] The aluminum nitride-graphite composite slurry in step 3 of Example 1 was replaced with zirconium-silicon integrated resin (containing 0.3 wt% modified graphene oxide), and all other preparation steps were completely consistent with those in Example 1. The results showed that due to severe phonon scattering in the zirconium carbide matrix, the planar thermal conductivity decreased, and the carbon fiber suffered a strength loss of up to 30% due to repeated high-temperature treatments, failing to meet the three-dimensional heat dissipation requirements of high-power devices.

[0060] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate, characterized in that: The steps are as follows: Step 1: Immerse the carbon fiber in a 5% nitric acid solution and react at 120°C for 4 hours to remove surface impurities. Then wash with deionized water until neutral and dry to obtain clean fiber. Place the clean fiber in a chemical vapor deposition furnace and react with 200 sccm of methyltrichlorosilane under argon atmosphere for 2 hours to obtain surface-modified carbon fiber. Step 2: The surface-modified carbon fibers obtained in Step 1 are woven into a three-dimensional orthogonal structure preform, and then filled with phenolic resin using a melt impregnation process to form a porous carbon fiber skeleton, providing a support framework for subsequent matrix composites. Step 3: 70wt% aluminum nitride powder and 30wt% graphite are ball-milled and mixed for 2 hours. Polysiloxane with a solid content of 65% is added and stirred evenly to obtain a mixed slurry. 15wt% ZrB2 powder and 0.5wt% titanium powder are added to the mixed slurry and ultrasonically dispersed for 30 minutes to obtain a uniformly dispersed slurry. The porous carbon fiber skeleton prepared in Step 2 is impregnated in the uniformly dispersed slurry for 2 hours and cured at 120℃ for 4 hours to obtain a preform. Step 4: Place the preform obtained in Step 3 in a high-temperature furnace, heat it to 1500℃ at 5℃ / min under an inert atmosphere and hold it for 2 hours. The generated TiN and TiC form TiCN solid solution to efficiently fill the pores of the matrix and obtain a densified matrix. Step 5: In the thickness direction of the densified matrix obtained in Step 4, a tapered through-hole is processed by laser. The channel of the tapered through-hole is filled with a premix of graphene oxide and phenolic resin modified with KH-550 silane coupling agent. The mixture is then hot-pressed and cured at 200°C and 2MPa for 1 hour. Next, it is decarburized in argon at 1400°C for 2 hours to form a porous graphene thermally conductive network. Finally, it is densified by pulsed chemical vapor deposition to obtain the finished heat-conducting plate. The parameters of the pulsed chemical vapor deposition are: methane flow rate of 500 sccm is introduced at 1800°C, the pulse gas supply time is 10s on and 5s off, and the total pulse gas supply time is greater than 1 hour.

2. The method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate according to claim 1, characterized in that: In step 1, the drying temperature is 150℃ and the drying time is 2 hours; the chemical vapor deposition furnace is heated from 800℃ to 1100℃ at a heating rate of 10℃ / min in an argon atmosphere, and then 200 sccm of methyltrichlorosilane is introduced.

3. The method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate according to claim 1, characterized in that: In step 2, the melt impregnation process involves injecting phenolic resin with a viscosity controlled at 200±20 mPa·s into the pores of the preform at 350℃±10℃ and 1.5MPa pressure, and then curing it in a nitrogen atmosphere at 180℃ for 3 hours.

4. The method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate according to claim 1, characterized in that: In step 3, the aluminum nitride powder particle size D 50 =0.5μm, the graphite particle size is ≤10μm, the ZrB2 powder particle size is 1-5μm, and the titanium powder particle size is ≤10μm.

5. The method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate according to claim 1, characterized in that: In step 4, the inert atmosphere is nitrogen, and the nitrogen partial pressure is ≥90%.

6. The method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate according to claim 1, characterized in that: In step 5, the tapered through-hole array is arranged on the machined surface of the substrate, and the machining density of the tapered through-hole is 60-80 holes / cm².

7. The method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate according to claim 1, characterized in that: In step 5, the tapered through hole has a top diameter of 50 μm, a bottom diameter of 200 μm, and a taper angle of 30°.

8. The method for preparing a carbon fiber reinforced ceramic encapsulated heat-conducting plate according to claim 1, characterized in that: In step 5, the mass ratio of the graphene oxide and phenolic resin premix is ​​3:

7.

9. The carbon fiber reinforced ceramic encapsulated heat-conducting plate prepared by any one of the preparation methods described in claims 1-8.