A porous ta c member, a method of manufacturing the same, and an application thereof

Abstract

The application belongs to the technical field of ultra-high temperature crystal growth, and more particularly relates to a porous TaC component, a preparation method and application thereof. The porous TaC component is prepared from TaC powder, other inorganic tantalum-containing powder and carbon-containing powder as raw materials, wherein the carbon-containing powder acts as a pore-forming agent and carbon source during sintering, the TaC acts as a skeleton material and does not participate in the reaction, the carbon-containing powder reacts with the inorganic tantalum-containing powder to newly generate TaC which acts as a connecting agent to connect the original TaC powder into a porous material at high temperature. By controlling the raw material ratio and sintering process parameters, the porosity and pore size distribution of the porous TaC component can be accurately controlled, so that the porous TaC component can effectively block graphite particles and does not affect the gas phase transport efficiency. The prepared porous TaC realizes near-net forming and does not need secondary processing. The porous TaC component is applied to SiC crystal growth, and the crystal defects are significantly reduced.

Description

Technical Field

[0001] This application belongs to the field of ultra-high temperature crystal growth technology, and more specifically, relates to a porous TaC component, its preparation method, and its application. Specifically, it relates to a porous TaC filter component for growing silicon carbide (SiC) crystals using the physical vapor transport (PVT) method and its preparation method. Background Technology

[0002] Silicon carbide (SiC) is an internationally recognized next-generation power electronic material, showing its potential in high power and high energy efficiency, and is widely used in various sectors of the national economy. Physical vapor transport (PVT) is the main growth method for preparing high-quality SiC crystals. This method involves placing powdered raw materials in a sealed container, sublimating the material at high temperature to form vapor, and then condensing the vapor into crystals by controlling the temperature gradient and pressure. However, in actual PVT growth of SiC crystals, the sublimation of the powder is not an ideal isostoichiometric process. Because the saturated vapor pressure of Si is significantly higher than that of C, in the early and middle stages of growth, a large amount of Si preferentially volatilizes in gaseous form, leading to severe non-stoichiometric sublimation in the bottom SiC powder region, i.e., graphitization of the powder. Under the influence of airflow and thermal convection, these tiny graphite dust particles are transported upwards with the sublimation airflow, directly adhering to or falling onto the growth interface of the growing crystal, resulting in a series of microscopic and macroscopic defects, such as micropipes (MPs), threading screw dislocations (TSDs), and basal plane dislocations (BPDs).

[0003] The existing approach involves placing a layer of porous graphite (PG) as a filter between the powder zone and the seed crystal. Porous graphite utilizes its labyrinthine pore structure to allow small-molecule gaseous components (Si(g), Si₂C(g), SiC₂(g)) to pass through, while simultaneously blocking large particles of free graphite dust through physical interception. However, in practical ultra-high temperature crystal growth applications, porous graphite is extremely susceptible to chemical corrosion from silicon-rich gases. In PVT environments above 2000 °C, the carbonaceous porous graphite framework undergoes the following violent chemical reaction with silicon-containing vapors: C(s) + Si(g) Si2C(g) C(s) + Si2C(g) SiC2(g) This reaction causes porous graphite to gradually lose its filtering ability during crystal growth, and may even generate new graphite particles, further increasing crystal defects. At the same time, porous graphite becomes a disposable material, increasing production costs.

[0004] Compared to graphite, TaC exhibits better corrosion resistance to silicon-rich gases at high temperatures. Therefore, porous TaC is a key technology for overcoming the current performance bottlenecks of porous graphite. Existing technologies for preparing porous TaC mainly include chemical vapor infiltration or chemical vapor deposition, organic slurry methods, molten salt methods, and powder sintering methods. Patent CN120136575A discloses a method for preparing porous TaC on the surface of porous graphite via chemical vapor infiltration; Patent CN119100829A uses an organic ligand source and a tantalum source to form a reactant with a porous organic framework structure, followed by high-temperature sintering to prepare porous TaC; Patent CN119431000A uses elemental metals or metal oxides as pore-forming agents, co-sintering them with TaC powder and carbon powder to form porous TaC; Patent CN120866944A uses tantalum or Ta2O5 powder and carbon powder for solid-phase sintering to prepare porous TaC. However, existing methods still face many challenges. For example, chemical vapor infiltration or chemical vapor deposition methods are costly and not conducive to large-scale industrialization. Organic slurry methods or molten salt methods introduce impurities other than C, Ta, and Si, resulting in low purity of porous TaC components. Powder sintering methods either introduce other metallic impurities, resulting in low purity of porous TaC components, or shrinkage and collapse occur during powder sintering, making it impossible to sinter porous TaC components that meet the requirements for preparing SiC crystals by PVT. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this application aims to provide a porous TaC component, its preparation method, and its applications. It seeks to solve the technical problems of existing TaC filter components used in the PVT method for SiC crystal preparation, such as high preparation cost, introduction of impurities, and shrinkage and collapse of the sintered body, preventing successful sintering. This invention is particularly suitable for use in ultra-high temperature crystal growth processes to block graphite particles in the material zone, improving crystal quality. Simultaneously, it resists silicon-rich vapor corrosion, extends service life, and enables reuse, making it applicable to the manufacturing of high-end electronic devices such as power devices and AR glasses.

[0006] To achieve the above objectives, in a first aspect, this application provides a method for preparing a porous TaC component, comprising the following steps: (1) Mix TaC powder, other inorganic tantalum-containing powders and carbon-containing powders and perform mixing treatment to obtain mixed raw material powder, without introducing other metal ions during the mixing process; the other inorganic tantalum-containing powders are selected from elemental tantalum other than TaC and inorganic tantalum-containing compounds; (2) The mixed raw material powder obtained in step (1) is molded to obtain a green body; (3) The green body obtained in step (2) is heated under vacuum to cause the carbon-containing powder in it to undergo a pyrolysis reaction. After volatilization, pores are left in the original carbon-containing powder particles in the green body, and pyrolytic carbon or silicon carbide remains, forming a preliminary porous framework. The temperature is further increased to the carbonization reaction temperature of the other inorganic tantalum-containing powders, so that the residual carbon or silicon carbide in the pores and other inorganic tantalum-containing powders undergo a diffusion reaction to generate TaC. In this process, the original carbon-containing powder acts as a pore-forming agent and carbon source, the original TaC powder acts as a framework material and does not participate in the reaction, and the carbon or silicon carbide left after the original carbon-containing powder volatilizes reacts with other inorganic tantalum-containing powders to generate TaC, which acts as a binder to connect the original TaC powder into a porous material. After cooling, a porous TaC component is obtained.

[0007] Preferably, the mass ratio of TaC powder, other inorganic tantalum-containing powder and carbon-containing powder in step (1) is (70-94):(5-20):(1-10).

[0008] More preferably, the D50 of the TaC powder in step (1) is greater than the D50 of the carbon-containing powder and the other inorganic tantalum-containing powder; and the D50 of the TaC powder is 50~300 μm.

[0009] Preferably, the other inorganic tantalum-containing powder is selected from one or more of metallic tantalum powder, Ta2O5 powder, TaN powder, TaSi2 powder and TaB2 powder; the D50 of the other inorganic tantalum-containing powder is 5~50 μm.

[0010] Preferably, the carbon-containing powder is selected from one or more of phenolic resin powder, polyurethane powder, polyvinyl alcohol powder, polycarbosilane powder, starch, and cellulose, and its D50 is 10~100 μm.

[0011] Preferably, step (3) specifically includes the following sub-steps: (3-1) Place the green body obtained in step (2) into a graphite crucible, then place it into a vacuum sintering furnace, evacuate to below 10 Pa, then heat to 1200~1500 ℃ at a heating rate of 30~200 ℃ / h, and then hold for 0.5~5 hours to allow the carbon-containing powder in it to undergo a pyrolysis reaction, leaving pores in the original carbon-containing powder particles in the green body and leaving pyrolytic carbon or silicon carbide residues, forming a preliminary porous framework; (3-2) Then, an inert atmosphere is introduced to adjust the furnace pressure to 500~900 mbar, and the temperature is linearly increased to 2000℃~2500℃. The furnace pressure is adjusted to 0~300 mbar so that the residual pyrolytic carbon or silicon carbide in the porous frame reacts with other inorganic tantalum-containing powders to form TaC. The reaction is maintained at the highest temperature for 5~30 hours to ensure that the reaction is complete. After the reaction is completed, the furnace pressure is increased to 500~900 mbar, the heater is turned off, and the furnace is cooled.

[0012] According to another aspect of the present invention, a porous TaC component prepared by the preparation method described above is provided.

[0013] According to another aspect of the invention, a filter medium for growing silicon carbide crystals by physical vapor transport method is provided, comprising the aforementioned porous TaC component.

[0014] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: (1) This invention prepares porous TaC components using TaC powder, other inorganic tantalum-containing powders, and carbon-containing powders as raw materials. It employs a composite synergistic process of in-situ reaction sintering and sacrificial pore-forming, overturning conventional processes. This invention cleverly utilizes a ternary high-purity precursor formulation system of "TaC powder (skeleton support) + other inorganic tantalum-containing powders (active connection source) + carbon-containing powder (dual function of pore-forming and carbon source)," achieving near-net-shape porous TaC without secondary processing. The porous TaC components of this invention are entirely composed of pure-phase TaC, possessing high purity characteristics and fundamentally eliminating deep-level impurity contamination of the semiconductor crystal.

[0015] (2) This invention uses TaC powder as the main raw material, and specifically controls the particle size and content of the raw material, with a content of 70% or more, and the D50 of the TaC powder is greater than that of the carbon-containing powder and the other inorganic tantalum-containing powders. According to the sintering procedure of this invention, the TaC powder, as a skeleton support material, does not react, while the other inorganic tantalum-containing powders react with the residual carbon after the pyrolysis of the carbon-containing powder at high temperature to act as a binder, connecting the TaC particles to obtain a porous TaC component. The particle size of the TaC raw material powder has a key influence on the porosity of the final porous TaC component. By controlling the particle size of the TaC raw material powder, the porosity and pore size distribution of the final porous TaC component can be controlled, so that it can effectively block graphite particles without affecting the gas phase transport efficiency.

[0016] (3) The porous TaC component prepared by the present invention has extremely strong chemical stability and high temperature resistance, and has better long-term effective filtration performance than porous graphite, which meets the stringent requirements for SiC crystal growth.

[0017] (4) The present invention uses high-purity porous TaC to replace the existing non-corrosion-resistant porous graphite and applies it to the process of growing large-size SiC crystals in PVT. Experiments have shown that its crystal defects are significantly reduced. Moreover, the service life of the porous TaC component of the present invention is also significantly better than that of porous graphite or porous TaC filter components prepared by existing technology.

[0018] (5) In the preparation of porous TaC components by the present invention, more than 70 wt% of the raw materials are TaC powder, which serves as the skeleton material. The preparation principle of the present invention is to connect the skeleton material TaC powder by sintering, wherein carbon-containing materials are used as pore-forming agents and carbon sources, and other inorganic tantalum-containing materials are used as binders. This preparation method can cleverly avoid the problems of shrinkage, collapse, and poor mechanical strength of TaC components that occur during the existing solid powder sintering process. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the fabrication process of porous TaC components according to this application; Figure 2 This is a schematic diagram of the porous TaC component provided in the embodiments of this application applied to the growth of SiC crystals by the PVT method; Figure 3 This is a scanning electron microscope image of the porous TaC prepared in Example 1 of this application.

[0020] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-Graphite crucible; 2-SiC powder; 3-Porous TaC component; 4-SiC seed crystal. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0022] To address the problems of porous graphite being easily corroded by silicon vapor and having a short lifespan during the PVT method for growing silicon carbide crystals, as well as the inability to form porous TaC components due to the introduction of impurities in the molten salt method, the high cost of the CVD method, and the large shrinkage rate of the powder sintering method, this invention provides a method for preparing porous TaC components. These components possess excellent resistance to high-temperature silicon vapor corrosion and good high-temperature stability, and can perfectly replace existing porous graphite and porous TaC materials. They achieve long-term effective filtration of graphite dust, thereby significantly reducing macroscopic and microscopic defects in large-size SiC crystals.

[0023] This invention provides a method for preparing porous TaC components, such as... Figure 1 As shown, it includes the following steps: (1) Mix TaC powder, other inorganic tantalum-containing powders and carbon-containing powders and perform mixing treatment to obtain mixed raw material powder, without introducing other metal ions during the mixing process; the other inorganic tantalum-containing powders are selected from elemental tantalum other than TaC or inorganic tantalum-containing compounds; (2) The mixed raw material powder obtained in step (1) is molded to obtain a green body; (3) The green body obtained in step (2) is heated under vacuum to cause the carbon-containing powder in it to undergo a pyrolysis reaction. After volatilization, pores are left in the original carbon-containing powder particles in the green body, and pyrolytic carbon or silicon carbide remains, forming a preliminary porous framework. The temperature is further increased to the carbonization reaction temperature of the other inorganic tantalum-containing powders, so that the residual carbon or silicon carbide in the pores undergoes a diffusion reaction with other inorganic tantalum-containing powders to generate TaC.

[0024] In this process, the original carbon-containing powder acts as a pore-forming agent and carbon source, while the original TaC powder acts as a framework material and does not participate in the reaction. The carbon or silicon carbide left after the original carbon-containing powder is carbonized reacts with other inorganic tantalum-containing powders to generate TaC, which acts as a binder to connect the original TaC powder into a porous material. After cooling, a porous TaC component is obtained.

[0025] In this invention, TaC powder is used as the main raw material and also serves as the skeleton material. In some embodiments, the mass ratio of TaC powder, other inorganic tantalum-containing powder and carbon-containing powder in step (1) is (70-94):(5-20):(1-10).

[0026] To improve molding quality, in a preferred embodiment, the D50 (median particle size) of the TaC powder in step (1) is greater than the D50 of the carbon-containing powder and the other inorganic tantalum-containing powders; and the D50 of the TaC powder is 50~300 μm, with a purity ≥99.9%; the other inorganic tantalum-containing powders are selected from one or more of metallic tantalum powder, Ta2O5 powder, TaN powder, TaSi2 powder, and TaB2 powder; the D50 of the other inorganic tantalum-containing powders is 5~50 μm, with a purity ≥99.9%; the carbon-containing powders are selected from one or more of phenolic resin powder, polyurethane powder, polyvinyl alcohol powder, polycarbosilane powder, starch, and cellulose, with a D50 of 10~100 μm. The raw materials prepared in this invention do not contain any other metal elements besides TaC powder, other inorganic tantalum-containing powders, and carbon-containing powders, to ensure high purity of the materials and meet the application requirements of semiconductor materials.

[0027] The present invention rationally sets the content of carbon-containing materials in the raw material powder. In a preferred embodiment, the carbon-containing powder accounts for less than 10 wt% of the total mass of the raw material powder, ensuring that the carbon-containing materials are fully pyrolyzed and reacted completely, leaving no carbon residue and not affecting the purity of the TaC component.

[0028] In some embodiments, the mixing process in step (1) is carried out in a vibratory mixer for 20 to 120 minutes. Preferably, the inner wall of the mixing tank is coated with a material such as TaC, SiC, carbon coating, polytetrafluoroethylene (PTFE), or polyurethane, which is required to prevent the introduction of other metal ions during the mixing process. In some preferred embodiments, the ratio of the loading volume to the volume of the vibratory mixing tank is 1 / 4 to 3 / 4, and the vibration frequency is 50 to 300 Hz.

[0029] In some embodiments, the compression molding in step (2) is performed at a pressure of 5-100 MPa and a holding time of 5-10 minutes.

[0030] Preferably, step (3) specifically includes the following sub-steps: (3-1) Place the green body obtained in step (2) into a graphite crucible, then into a vacuum sintering furnace, evacuate to below 10 Pa, then heat to 1200~1500 ℃ at a heating rate of 30~200 ℃ / h, and then hold for 0.5~5 hours to allow the carbon-containing powder to undergo a pyrolysis reaction, leaving pores in the original carbon-containing powder particles in the green body and leaving pyrolytic carbon or silicon carbide residues, forming a preliminary porous framework; the purpose of this step is to remove the powder and impurity gases inside the furnace cavity, while the carbon-containing powder undergoes pyrolysis and volatilization upon heating.

[0031] (3-2) Then, an inert atmosphere is introduced to adjust the furnace pressure to 500~900 mbar, and the temperature is linearly increased to 2000℃~2500℃. The furnace pressure is adjusted to 0~300 mbar. The pyrolytic carbon or silicon carbide remaining in the porous frame reacts with other inorganic tantalum-containing powders to form TaC. The reaction is maintained at the highest temperature for 5~30 hours to ensure that the reaction is complete. After the reaction is completed, the furnace pressure is increased to 500~900 mbar, the heater is turned off, and the furnace is cooled.

[0032] In step (3-2), an inert atmosphere is first introduced to adjust the furnace pressure to a relatively high pressure of 500~900 mbar to avoid Ta and C reacting during the heating process; after heating to 2000℃~2500℃, the furnace pressure is reduced to 0~300 mbar to initiate the reaction of Ta and C to generate TaC at high temperature; after the reaction is completed, the furnace pressure is increased to 500~900 mbar to accelerate cooling.

[0033] In some embodiments, the inert gas introduced in step (3-2) (which is inert in the system of the present invention, does not participate in the reaction, or is called a non-oxidizing gas) is selected from one or more of Ar, He, and H2, and the total gas flow rate is 50~1000 sccm.

[0034] The present invention also provides a porous TaC component prepared by the above-described method. In a preferred embodiment, the component has a porosity of 30-70%, an average pore size of 20-100 μm, and a density of 4.35-10.15 g / cm³. 3 The evenly distributed pores ensure effective filtration and good airflow.

[0035] The present invention provides a porous TaC filter element for growing silicon carbide (SiC) crystals by physical vapor transport (PVT) method, comprising the porous TaC element as described above.

[0036] This invention provides a method for preparing porous TaC components. This method innovatively employs a composite mechanism of "high-purity raw materials + in-situ reaction bonding + sacrificial template pore-forming," using TaC powder as the framework and other inorganic tantalum-containing powders as the in-situ reaction source and binder. The carbon-containing powder serves as both a carbon source and a pore-forming agent, achieving near-net-shape forming of porous TaC without secondary processing. The entire preparation process requires no addition of other metal elements, ensuring that the components meet extremely high semiconductor-grade purity requirements. This process is applicable to the field of ultra-high temperature crystal growth, especially 8-inch and 12-inch compound crystals. Through optimized process configuration, it enables large-scale industrial production of low-defect crystals, providing high-quality basic materials for high-end power devices and AR glasses light-emitting devices.

[0037] A method for preparing a porous TaC component, provided in some embodiments of the present invention, includes the following steps: 1) Raw material preparation: Mix the following raw materials according to the following mass ratio: TaC powder, other inorganic tantalum-containing powders, and carbon-containing powders. The raw materials must not contain other metal elements to ensure high purity and meet the requirements of semiconductor material applications. The preferred raw material ratio is: 70-94 wt% TaC powder, 5-20 wt% other inorganic tantalum-containing powders, and 1-10 wt% carbon-containing powders.

[0038] 2) Raw material mixing: The mixed raw materials are placed in a vibratory mixer for mixing for 20-120 minutes. The inner wall of the mixing tank is coated with materials such as TaC, SiC, carbon coating, polytetrafluoroethylene (PTFE), and polyurethane. It is required that no other metal ions are introduced during the mixing process. The volume of the vibratory mixing tank is 1-2 L, and the ratio of the loading volume to the volume of the vibratory mixing tank is 1 / 4-3 / 4. The vibration frequency is 50-300 Hz.

[0039] 3) Compression molding: The mixed powder is loaded into the prototype graphite mold and compression molded. The pressure is 1~100MPa, the holding time is 5~10 minutes, and the molding temperature is room temperature to obtain the green body.

[0040] 4) High-temperature sintering: The green blank is placed in a graphite crucible and then placed in a vacuum sintering furnace for high-temperature sintering. The sintering temperature is 2000℃~2500℃, the sintering pressure is 0~300 mbar, and the sintering time is 5~30 hours. The heating formula is as follows: first, vacuum heat to 1200~1500℃ at a heating rate of 30~200℃ / h, and then hold at that temperature for 0.5~5 hours. The purpose is to remove the powder and impurity gases inside the furnace cavity. At the same time, the carbon-containing powder reacts to generate carbon-containing materials, leaving pores in the original carbon-containing particles and retaining pyrolytic carbon or silicon carbide, thus initially forming a porous framework. Inert gas is then introduced, the furnace pressure is adjusted to 500-900 mbar, and the temperature is linearly increased to 2000-2500 °C. The furnace pressure is then adjusted to 0-300 mbar. The residual carbon within the porous framework reacts with the inorganic tantalum-containing powder to form TaC. This reaction is maintained at the highest temperature for 5-30 hours to ensure complete reaction. After the reaction, the furnace pressure is increased to 500-900 mbar, the heater is turned off, and the furnace is cooled. During sintering, one or more of Ar, He, and H2 can be used as the inert gas, with a total flow rate of 50-1000 sccm.

[0041] 5) Cooling treatment: After sintering, the material is naturally cooled to room temperature to obtain porous TaC components.

[0042] The porous TaC component provided by this invention has a geometric dimension that can be flexibly designed according to the target SiC crystal size, and the different TaC component sizes required for crystal growth can be matched by adjusting the green blank size. Porous TaC component for 8-inch SiC crystal growth: Diameter D: 200 mm ≤ D ≤ 250 mm; Thickness: 2~10 mm; Preferred size: Diameter 220 mm, Thickness 5 mm. Porous TaC component for 12-inch SiC crystal growth: Diameter D: 300 mm ≤ D ≤ 350 mm; Thickness: 3~15 mm; Preferred size: Diameter 320 mm, Thickness 8 mm.

[0043] The principle of this invention for preparing porous TaC components is as follows: In the medium-high temperature range (temperature below or equal to 1500 ℃), carbon-containing powders (such as polyurethane, polycarbosilane, etc.) uniformly distributed in the powder blank undergo pyrolysis and volatilization, leaving pores and carbon-containing material in the positions originally occupied by carbon-containing particles, forming a preliminary porous framework. The pores of the preliminary porous framework originate from the gaps between the framework TaC powders and the pores generated by the volatilization of carbon-containing powders. When the temperature continues to rise to the carbonization reaction temperature of inorganic tantalum-containing powders (temperature above or equal to 2000 ℃), the carbon medium within the channels begins to diffuse and react with other inorganic tantalum-containing powders (inorganic tantalum-containing powder + C → TaC), while the original TaC powder does not undergo a chemical reaction. At the microscopic level, because the inorganic tantalum-containing powders are distributed in the gaps between the TaC framework particles, the newly formed TaC preferentially nucleates and grows on the surface of the original inorganic tantalum-containing powder particles and at the contact points with the TaC framework. This in-situ generated TaC acts as an "inorganic binder," forming robust sintered necks between adjacent TaC framework particles through metallurgical bonding, firmly welding the originally discrete TaC particles together. The carbon-containing powder acts as a pore-forming agent and carbon source, while the original TaC serves as a framework material and does not participate in the reaction. At high temperatures, the residual carbon or silicon carbide from the pyrolysis of the carbon-containing powder reacts with the inorganic tantalum-containing powder to generate new TaC, which acts as a binder, connecting the original TaC powder into a porous material.

[0044] Traditional methods for preparing porous TaC using powder sintering suffer from drawbacks. Since both tantalum and carbon powders participate in the reaction, the green body shrinks and collapses during sintering, making it impossible to form a solid mass. Even when it appears formed, shrinkage leads to high internal stress in the porous TaC product, making it prone to cracking and resulting in a short lifespan. This invention cleverly designs the raw materials for porous TaC components to contain over 70 wt% TaC powder. This powder acts as a framework particle and does not react during the sintering and pore-forming process, ensuring controllable porosity and making it easier to obtain porous TaC materials with uniform pores and low internal stress. Furthermore, through formulation design, the carbon-containing materials fully volatilize at high temperatures and react completely with other inorganic tantalum-containing powders, resulting in a product free of impurities, suitable for application in semiconductor crystal manufacturing processes.

[0045] Furthermore, this invention uses TaC powder as the main raw material and specifically controls the initial particle size and ratio of the TaC powder raw material to ensure that its content is 70wt% or higher. Moreover, the D50 of the TaC powder must be greater than that of the carbon-containing powder and the other inorganic tantalum-containing powders. Thus, according to the sintering process of this invention, the TaC powder, as a skeleton support material, does not react. The other inorganic tantalum-containing powders react with the residual carbon after the pyrolysis of the carbon-containing powder at high temperature to act as a binder (also known as a binder), connecting the TaC particles together. Finally, a porous TaC filter component with a porosity and pore size (20-100μm) suitable for the PVT method to prepare SiC crystals is obtained, which can effectively block graphite particles without affecting the gas phase transport efficiency.

[0046] A typical application of the porous TaC provided by this invention is the PVT growth of SiC crystals. For example... Figure 2 As shown, in the graphite crucible 1, a porous TaC component 3 is installed between the SiC powder 2 and the SiC seed crystal 4 as a filter medium. The distance between the porous TaC and the upper surface of the powder is 0~50 mm, and the distance between the porous TaC and the lower surface of the seed crystal is 50~200 mm. The porous TaC serves as a filter medium for Si / C vapor.

[0047] The working principle of porous TaC in the SiC crystal growth process: Since PVT growth of SiC crystals uses SiC powder as raw material, and SiC sublimates non-stoichiometrically at high temperatures, the silicon component is easily volatilized while the carbon component is not, leading to carbonization in the powder area, i.e., the formation of a large number of graphite particles. These graphite particles cause numerous defects when transported to the SiC bulk surface by Si / C vapor. Therefore, porous TaC is needed as a filter medium. When graphite particles pass through the porous TaC component with the vapor flow, because the size of the graphite particles is larger than the internal pore size of the porous TaC, the porous TaC can block the graphite particles in the powder area, preventing them from entering the crystal growth region. Simultaneously, due to the excellent chemical stability of TaC in the Si / C vapor environment, the porous TaC component can maintain its structural integrity for a long time, is not easily corroded, thus extending its service life and enabling repeated use.

[0048] The embodiments of the present invention are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and processes are given. However, the protection scope of the present invention is not limited to the following embodiments. Process parameters not specified in the following embodiments are generally performed under conventional conditions. The D50 (median particle size) of the powder in the following embodiments and comparative examples was measured by a laser particle size analyzer (Mastersizer 3000+).

[0049] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include those approximate to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0050] Example 1 Preparation of porous TaC components and application in 8-inch SiC crystal growth (Ta2O5 as tantalum source, phenolic resin powder as carbon source). 1. Material Preparation and Proportioning: Select TaC powder with a purity ≥99.99% and a D50 of 100 μm as the skeleton, Ta2O5 powder with a D50 of 10 μm, and phenolic resin powder with a purity ≥99.999% and a D50 of 20 μm (CAS: 9003-35-4; molecular weight 8000~13000; electronic grade). Weigh out the following components by mass percentage: 75wt% TaC powder, 20wt% Ta2O5 powder, and 5wt% phenolic resin powder.

[0051] 2. Mixing: Place the above powder in a mixing tank with a TaC coating inside. The ratio of the filling volume to the mixing tank volume is 1 / 2. The vibration frequency is 200 Hz. Place the mixed raw materials into a vibrating mixer for mixing for 60 minutes.

[0052] 3. Compression molding: Take an appropriate amount of mixed powder and fill it into a circular graphite mold with an inner diameter of 220 mm. Perform compression molding under a pressure of 5 MPa. The compression temperature is room temperature. Hold the pressure for 5 minutes and demold to obtain a disc-shaped green body with a diameter of about 220 mm and a thickness of about 5 mm.

[0053] 4. Sintering: Place the green blank into a graphite crucible, then into a vacuum sintering furnace. Evacuate to 5 × 10⁻⁶ m³ / h. -4 Below Pa, the temperature was increased to 1300 °C at a rate of 50 °C / min and held under vacuum for 4 hours. The Ar valve was opened, and 500 sccm of argon gas was introduced to increase the furnace pressure to 700 mbar. Then, the temperature was increased to 2200 °C at a rate of 50 °C / min. The furnace pressure was reduced to 50 mbar and held at the highest temperature for 10 hours. Ta₂O₅ powder reacted with the carbon source to form TaC. The TaC powder particles bonded together to form a three-dimensional pure-phase porous TaC material. After the reaction, the furnace pressure was increased to 800 mbar, the heater was turned off, and the furnace was allowed to cool. SEM analysis was performed on the cross-section of the prepared porous TaC component. The scanning electron microscope images are shown below. Figure 3 As shown, the porous TaC component prepared in this embodiment has a porous structure and uniform pore size.

[0054] 5. Crystal growth verification: The porous TaC was placed in the SiC crystal growth crucible, with the porous TaC located between the powder and the seed crystal. The porous TaC was 30 mm away from the upper surface of the powder, and the porous graphite was 70 mm away from the seed crystal. The crucible was placed in the graphite heat preservation field, and the growth temperature was set to 2200 ℃, the growth pressure to 10 mbar, and the crystal growth time to 180 h.

[0055] 6. Physical property testing: After the SiC crystal growth is completed, the crystal is processed by slicing, grinding, polishing and other processes, and defect analysis is performed.

[0056] Example 2 Preparation of porous TaC components and application in 8-inch SiC crystal growth (Ta2O5 as tantalum source, polycarbosilane powder as carbon source). 1. Material Preparation and Proportioning: Select TaC powder with a purity ≥99.99% and a D50 of 100 μm as the framework, Ta2O5 powder with a D50 of 5 μm, and polycarbosilane powder with a purity ≥99.999% and a D50 of 20 μm (CAS: 62306-27-8; molecular weight 1000~2000; high purity). Weigh the following components by mass percentage: 75wt% TaC powder, 15wt% Ta2O5 powder, and 10wt% polycarbosilane powder.

[0057] 2. Mixing: Place the above powder in a mixing tank with a TaC coating inside. The ratio of the filling volume to the mixing tank volume is 1 / 3. The vibration frequency is 200 Hz. Place the mixed raw materials into a vibrating mixer for mixing for 30 minutes.

[0058] 3. Compression molding: Take an appropriate amount of mixed powder and fill it into a circular graphite mold with an inner diameter of 220 mm. Perform compression molding under a pressure of 20 MPa. The compression temperature is room temperature. Hold the pressure for 10 minutes and demold to obtain a disc-shaped green body with a diameter of about 220 mm and a thickness of about 5 mm.

[0059] 4. Sintering: Place the green blank into a graphite crucible, then into a vacuum sintering furnace. Evacuate to 5 × 10⁻⁶ m³ / h. -4 Below Pa, the temperature was increased to 1500 °C at a rate of 50 °C / min and held under vacuum for 2 hours. The Ar valve was opened, and 600 sccm of argon gas was introduced to raise the furnace pressure to 800 mbar. The temperature was then increased to 2400 °C at a rate of 50 °C / min. The furnace pressure was reduced to 100 mbar and held at the highest temperature for 10 hours. The Ta₂O₅ powder reacted with the carbon source to form TaC. The TaC powder particles bonded together to form a three-dimensional pure-phase TaC porous material. After the reaction was complete, the furnace pressure was increased to 700 mbar, the heater was turned off, and the furnace was cooled.

[0060] 5. Crystal growth verification: The porous TaC was placed in the SiC crystal growth crucible, with the porous TaC located between the powder and the seed crystal. The porous TaC was 30 mm away from the upper surface of the powder, and the porous graphite was 70 mm away from the seed crystal. The crucible was placed in the graphite heat preservation field, and the growth temperature was set to 2200 ℃, the growth pressure to 10 mbar, and the crystal growth time to 180 h.

[0061] 6. Physical property testing: After the SiC crystal growth is completed, the crystal is processed by slicing, grinding, polishing and other processes, and defect analysis is performed.

[0062] Example 3 Fabrication of porous TaC components and application in 12-inch SiC crystal growth (Ta powder as tantalum source, polyurethane powder as carbon source). 1. Material Preparation and Proportioning: Select TaC powder with a purity ≥99.99% and a D50 of 200 μm as the skeleton, Ta powder with a D50 of 20 μm, and polyurethane powder with a purity ≥99.99% and a D50 of 50 μm (CAS: 9009-54-5; molecular weight approximately 5000 g / mol; high purity). Weigh the following components by mass percentage: 80 wt% TaC powder, 10 wt% Ta powder, and 10 wt% polyurethane powder.

[0063] 2. Mixing: Place the above powder in a mixing tank with a TaC coating inside. The ratio of the filling volume to the mixing tank volume is 1 / 2. The vibration frequency is 200 Hz. Place the mixed raw materials into a vibrating mixer for mixing for 60 minutes.

[0064] 3. Compression molding: Take an appropriate amount of mixed powder and fill it into a circular graphite mold with an inner diameter of 320 mm. Perform compression molding under a pressure of 5 MPa. The compression temperature is room temperature. Hold the pressure for 10 minutes and demold to obtain a disc-shaped green body with a diameter of about 320 mm and a thickness of about 8 mm.

[0065] 4. Sintering: Place the green blank into a graphite crucible, then into a vacuum sintering furnace. Evacuate to 5 × 10⁻⁶ m³ / h. -4 Below Pa, the temperature was increased to 1400 °C at a rate of 50 °C / min and held under vacuum for 4 hours. The Ar valve was opened, and 800 sccm of argon gas was introduced to raise the furnace pressure to 900 mbar. The temperature was then increased to 2300 °C at a rate of 50 °C / min. The furnace pressure was reduced to 10 mbar and held at the highest temperature for 20 hours. Ta powder reacted with the carbon source to form TaC, and the TaC powder particles bonded together to form a three-dimensional pure-phase TaC porous material. After the reaction was complete, the furnace pressure was increased to 900 mbar, the heater was turned off, and the furnace was cooled.

[0066] 5. Crystal growth verification: The porous TaC was placed in the SiC crystal growth crucible, with the porous TaC located between the powder and the seed crystal. The porous TaC was 30 mm away from the upper surface of the powder, and the porous graphite was 70 mm away from the seed crystal. The crucible was placed in the graphite heat preservation field, and the growth temperature was set to 2200 ℃, the growth pressure to 10 mbar, and the crystal growth time to 180 h.

[0067] 6. Physical property testing: After the SiC crystal growth is completed, the crystal is processed by slicing, grinding, polishing and other processes, and defect analysis is performed.

[0068] Example 4 Fabrication of porous TaC components and application in 12-inch SiC crystal growth (TaSi2 powder as tantalum source, polyvinyl alcohol powder as carbon source). 1. Material Preparation and Proportioning: Select TaC powder with a purity ≥99.99% and a D50 of 80 μm as the skeleton, TaSi2 powder with a D50 of 30 μm, and polyvinyl alcohol powder with a purity ≥99.999% and a D50 of 10 μm (CAS: 9002-89-5; molecular weight 120,000~150,000, high purity). Weigh out the following components by mass percentage: 90wt% TaC powder, 8wt% TaSi2 powder, and 2wt% polyvinyl alcohol powder.

[0069] 2. Mixing: Place the above powder in a mixing tank with a TaC coating inside. The ratio of the filling volume to the mixing tank volume is 3 / 4. The vibration frequency is 300 Hz. Place the mixed raw materials into a vibrating mixer for mixing for 60 minutes.

[0070] 3. Compression molding: Take an appropriate amount of mixed powder and fill it into a circular graphite mold with an inner diameter of 340 mm. Perform compression molding under a pressure of 50 MPa. The compression temperature is room temperature. Hold the pressure for 5 minutes and demold to obtain a disc-shaped green body with a diameter of about 340 mm and a thickness of about 10 mm.

[0071] 4. Sintering: Place the green blank into a graphite crucible, then into a vacuum sintering furnace. Evacuate to 5 × 10⁻⁶ m³ / h. -4 Below Pa, the temperature was increased to 1200 °C at a rate of 50 °C / min and held under vacuum for 4 hours. The Ar valve was opened, and 500 sccm of argon gas was introduced to increase the furnace pressure to 700 mbar. The temperature was then increased to 2250 °C at a rate of 50 °C / min. The furnace pressure was reduced to 5 mbar and held at the highest temperature for 30 hours. The TaSi2 powder reacted with the carbon source to form TaC, and the TaC powder particles bonded together to form a three-dimensional pure-phase TaC porous material. After the reaction was complete, the furnace pressure was increased to 500 mbar, the heater was turned off, and the furnace was cooled.

[0072] 5. Crystal growth verification: The porous TaC was placed in the SiC crystal growth crucible, with the porous TaC located between the powder and the seed crystal. The porous TaC was 30 mm away from the upper surface of the powder, and the porous graphite was 70 mm away from the seed crystal. The crucible was placed in the graphite heat preservation field, and the growth temperature was set to 2200 ℃, the growth pressure to 10 mbar, and the crystal growth time to 180 h.

[0073] 6. Physical property testing: After the SiC crystal growth is completed, the crystal is processed by slicing, grinding, polishing and other processes, and defect analysis is performed.

[0074] Example 5 The rest is the same as in Example 1, except that in step 1, the materials are prepared and proportioned as follows: TaC powder with a purity of ≥99.99% and a D50 of 300 μm is selected as the skeleton, Ta2O5 powder with a D50 of 50 μm is selected, and phenolic resin powder with a purity of ≥99.999% and a D50 of 100 μm is selected.

[0075] Comparative Example 1 8-inch SiC crystal growth using porous graphite 1. Crystal growth verification: The same growth process as in Example 1 above was adopted, using porous graphite as the growth filter medium. The porous graphite grade was: Cermaco, P401. The porous graphite was located between the powder and the seed crystal, with the porous graphite 30 mm away from the upper surface of the powder and 70 mm away from the seed crystal. The crucible was placed in a graphite heat preservation field, and the growth temperature was set to 2200 ℃, the growth pressure to 10 mbar, and the crystal growth time to 180 h.

[0076] 2. Physical property testing: After the SiC crystal growth is completed, the crystal is processed by slicing, grinding, polishing and other processes, and defect analysis is performed.

[0077] Comparative Example 2 Preparation of porous TaC components and application in 8-inch SiC crystal growth (Ta2O5 as tantalum source, phenolic resin powder as carbon source). 1. Material Preparation and Proportioning: Select TaC powder with a purity ≥99.99% and a D50 of 100 μm as the framework, Ta2O5 powder with a D50 of 5 μm, and phenolic resin powder with a purity ≥99.999% and a D50 of 20 μm (CAS: 9003-35-4; molecular weight 8000~13000; high purity). Weigh the following components by mass percentage: 75wt% TaC powder, 20wt% Ta2O5 powder, and 5wt% phenolic resin powder.

[0078] 2. Mixing: Place the above powder in a mixing tank with a TaC coating inside. The ratio of the filling volume to the mixing tank volume is 1 / 2. The vibration frequency is 200 Hz. Place the mixed raw materials into a vibrating mixer for mixing for 60 minutes.

[0079] 3. Compression molding: Take an appropriate amount of mixed powder and fill it into a circular graphite mold with an inner diameter of 220 mm. Perform compression molding under a pressure of 0.5 MPa. The compression temperature is room temperature. Hold the pressure for 5 minutes and demold to obtain a disc-shaped green body with a diameter of about 220 mm and a thickness of about 5 mm.

[0080] 4. Sintering: Place the green blank into a graphite crucible, then into a vacuum sintering furnace. Evacuate to 5 × 10⁻⁶ m³ / h. -4 Below Pa, the temperature is increased to 1300 °C at a rate of 50 °C / min and held under vacuum for 4 hours. The Ar valve is opened, and 600 sccm of argon gas is introduced to raise the furnace pressure to 700 mbar. The temperature is then increased to 1800 °C at a rate of 50 °C / min. The furnace pressure is reduced to 50 mbar and held at the highest temperature for 10 hours. The furnace pressure is then increased to 800 mbar, the heater is turned off, and the furnace is allowed to cool.

[0081] Comparative Example 3 Preparation of porous TaC components and application in 8-inch SiC crystal growth (Ta2O5 as tantalum source, phenolic resin powder as carbon source). 1. Material Preparation and Proportioning: Select TaC powder with a purity ≥99.99% and a D50 of 100 μm as the skeleton, Ta2O5 powder with a D50 of 10 μm, and phenolic resin powder with a purity ≥99.999% and a D50 of 20 μm (CAS: 9003-35-4; molecular weight 8000~13000; electronic grade). Weigh out the following components by mass percentage: 50wt% TaC powder, 25wt% Ta2O5 powder, and 25wt% phenolic resin powder.

[0082] 2. Mixing: Place the above powder in a mixing tank with a TaC coating inside. The ratio of the filling volume to the mixing tank volume is 1 / 2. The vibration frequency is 200 Hz. Place the mixed raw materials into a vibrating mixer for mixing for 60 minutes.

[0083] 3. Compression molding: Take an appropriate amount of mixed powder and fill it into a circular graphite mold with an inner diameter of 220 mm. Perform compression molding under a pressure of 0.5 MPa. The compression temperature is room temperature. Hold the pressure for 5 minutes and demold to obtain a disc-shaped green body with a diameter of about 220 mm and a thickness of about 5 mm.

[0084] 4. Sintering: Place the green blank into a graphite crucible, then into a vacuum sintering furnace. Evacuate to 5 × 10⁻⁶ m³ / h. -4 Below Pa, the temperature is increased to 1300 °C at a rate of 50 °C / min and held under vacuum for 4 hours. The Ar valve is opened, and 600 sccm of argon gas is introduced to raise the furnace pressure to 700 mbar. The temperature is then increased to 2200 °C at a rate of 50 °C / min. The furnace pressure is reduced to 50 mbar and held at the highest temperature for 10 hours. The furnace pressure is then increased to 800 mbar, the heater is turned off, and the furnace is allowed to cool.

[0085] Comparative Example 4 Preparation of porous TaC components and application in 8-inch SiC crystal growth (Ta2O5 as tantalum source, phenolic resin powder as carbon source). 1. Material Preparation and Proportioning: Select TaC powder with a purity ≥99.99% and a D50 of 10 μm as the skeleton, Ta2O5 powder with a D50 of 10 μm, and phenolic resin powder with a purity ≥99.999% and a D50 of 20 μm (CAS: 9003-35-4; molecular weight 8000~13000; electronic grade). Weigh out the following components by mass percentage: 75wt% TaC powder, 20wt% Ta2O5 powder, and 5wt% phenolic resin powder.

[0086] 2. Mixing: Place the above powder in a mixing tank with a TaC coating inside. The ratio of the filling volume to the mixing tank volume is 1 / 2. The vibration frequency is 200 Hz. Place the mixed raw materials into a vibrating mixer for mixing for 60 minutes.

[0087] 3. Compression molding: Take an appropriate amount of mixed powder and fill it into a circular graphite mold with an inner diameter of 220 mm. Perform compression molding under a pressure of 0.5 MPa. The compression temperature is room temperature. Hold the pressure for 5 minutes and demold to obtain a disc-shaped green body with a diameter of about 220 mm and a thickness of about 5 mm.

[0088] 4. Sintering: Place the green blank into a graphite crucible, then into a vacuum sintering furnace. Evacuate to 5 × 10⁻⁶ m³ / h. -4 Below Pa, the temperature is increased to 1300 °C at a rate of 50 °C / min and held under vacuum for 4 hours. The Ar valve is opened, and 600 sccm of argon gas is introduced to raise the furnace pressure to 700 mbar. The temperature is then increased to 2200 °C at a rate of 50 °C / min. The furnace pressure is reduced to 50 mbar and held at the highest temperature for 10 hours. The furnace pressure is then increased to 800 mbar, the heater is turned off, and the furnace is allowed to cool.

[0089] Comparative Example 5 The other examples are the same as Comparative Example 4, except that in step 1, TaC powder with a purity of ≥99.99% and a D50 of 1 μm is selected as the framework.

[0090] Table 1. Effects of porous filter media used in SiC crystal growth according to the examples and comparative examples.

[0091] The porosity and average pore size of the porous TaC components in Table 1 were determined by mercury intrusion porosimetry, and the pore morphology was obtained by SEM cross-sectional inspection. Crystal quality testing method: The PVT-grown SiC crystals underwent standard grinding, rounding, multi-cutting, thinning, polishing, chamfering, and cleaning, and were then placed in a SiC wafer defect testing instrument (KLA, Candela 8520 or Lasertec, SICA88) to obtain the number of microtubes and inclusions.

[0092] As shown in Table 1, in the embodiments of the present invention, after molding the raw material powder obtained by mixing TaC powder, other inorganic tantalum-containing powders, and carbon-containing powders, porous TaC components with suitable porosity and pore size can be prepared under a suitable sintering procedure. When applied to the PVT method for growing silicon carbide crystals, the defects in the grown silicon carbide crystals are significantly reduced compared to using traditional porous graphite as a filter (Comparative Example 1). The sintering temperature of Comparative Example 2 was too low, and the resulting porous TaC was brittle. In Comparative Example 3, when the TaC raw material powder content was reduced to 50 wt%, the preform shrank severely and failed to form a shape during sintering, and the test showed that a large amount of carbon remained in the sintered product. In Comparative Examples 4 and 5, the initial TaC powder particle size was too small, which may be due to the higher reactivity of small-particle TaC, resulting in dense TaC, and the sintered body shrank and collapsed, making it impossible to produce porous TaC components.

[0093] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing a porous TaC component, characterized in that, Includes the following steps: (1) Mix TaC powder, other inorganic tantalum-containing powders and carbon-containing powders and perform a mixing process to obtain a mixed raw material powder, without introducing other metal ions during the mixing process; the other inorganic tantalum-containing powders are selected from elemental tantalum other than TaC and inorganic tantalum-containing compounds; (2) The mixed raw material powder obtained in step (1) is molded to obtain a green body; (3) The green body obtained in step (2) is heated under vacuum to cause the carbon-containing powder in it to undergo a pyrolysis reaction. After volatilization, pores are left in the original carbon-containing powder particles in the green body, and pyrolytic carbon or silicon carbide remains, forming a preliminary porous framework. The temperature is further increased to the carbonization reaction temperature of the other inorganic tantalum-containing powders, so that the residual carbon or silicon carbide in the pores and other inorganic tantalum-containing powders undergo a diffusion reaction to generate TaC. In this process, the original carbon-containing powder acts as a pore-forming agent and carbon source, the original TaC powder acts as a framework material and does not participate in the reaction, and the carbon or silicon carbide left after the original carbon-containing powder volatilizes reacts with other inorganic tantalum-containing powders to generate TaC, which acts as a binder to connect the original TaC powder into a porous material. After cooling, a porous TaC component is obtained.

2. The preparation method according to claim 1, characterized in that, The mass ratio of TaC powder, other inorganic tantalum-containing powder and carbon-containing powder in step (1) is (70-94): (5-20): (1-10).

3. The preparation method according to claim 1, characterized in that, In step (1), the D50 of the TaC powder is greater than that of the carbon-containing powder and the other inorganic tantalum-containing powders; and the D50 of the TaC powder is 50~300 μm; and / or, The other inorganic tantalum-containing powder is selected from one or more of metallic tantalum powder, Ta₂O₅ powder, TaN powder, TaSi₂ powder, and TaB₂ powder; the D50 of the other inorganic tantalum-containing powder is 5~50 μm; and / or, The carbon-containing powder is selected from one or more of phenolic resin powder, polyurethane powder, polyvinyl alcohol powder, polycarbosilane powder, starch and cellulose, and its D50 is 10~100 μm.

4. The preparation method according to claim 1, characterized in that, The mixing process described in step (1) is carried out in a vibrating mixer for a mixing time of 20 to 120 minutes.

5. The preparation method according to claim 1, characterized in that, The molding process described in step (2) involves a pressure of 5~100MPa and a holding time of 5~10 minutes.

6. The preparation method according to claim 1, characterized in that, Step (3) specifically includes the following sub-steps: (3-1) Place the green body obtained in step (2) into a graphite crucible, then place it into a vacuum sintering furnace, evacuate to below 10 Pa, then heat to 1200~1500 ℃ at a heating rate of 30~200 ℃ / h, and then hold for 0.5~5 hours to allow the carbon-containing powder in it to undergo a pyrolysis reaction, leaving pores in the original carbon-containing powder particles in the green body and leaving pyrolytic carbon or silicon carbide residues, forming a preliminary porous framework; (3-2) Then, an inert atmosphere is introduced to adjust the furnace pressure to 500~900 mbar, and the temperature is linearly increased to 2000℃~2500℃. The furnace pressure is adjusted to 0~300 mbar so that the residual pyrolytic carbon or silicon carbide in the porous frame reacts with other inorganic tantalum-containing powders to form TaC. The reaction is maintained at the highest temperature for 5~30 hours to ensure that the reaction is complete. After the reaction is completed, the furnace pressure is increased to 500~900 mbar, the heater is turned off, and the furnace is cooled.

7. The preparation method according to claim 6, characterized in that, The inert atmosphere introduced in step (3-2) is selected from one or more of Ar, He, and H2, and the total flow rate is 50~1000 sccm.

8. The porous TaC component prepared by the preparation method according to any one of claims 1 to 7.

9. The porous TaC component as described in claim 8, characterized in that, Its porosity is 30-70%, and the average pore size is 20-100 μm.

10. A filter medium for growing silicon carbide crystals using physical vapor transport method, characterized in that, It contains a porous TaC component as described in claim 8 or 9.

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