Method for preparing Ta-Hf-C ceramic powder by combining solvothermal treatment with carbothermal reduction
Ta-Hf-C ceramic powder was prepared by solvent thermal treatment combined with carbon thermal reduction, which solved the problem of high purity and ultrafine particle size, achieved good sintering performance and industrial production, and is suitable for the preparation of high-temperature ceramic materials.
Patent Information
- Application Number
- CN202510917289.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-03
- Publication Date
- 2025-09-12
AI Technical Summary
Existing technologies make it difficult to efficiently prepare high-purity and ultrafine-particle Ta-Hf-C ceramic powders, and sintering is difficult to densify, limiting their application in extreme service environments.
Ta-Hf-C ceramic powders were prepared by solvent thermal treatment combined with carbothermal reduction. The mixture was stirred in a water bath, treated in a hydrothermal reactor, dried, and calcined in a tube furnace. The molar ratio of metal chlorides was controlled to regulate the powder morphology.
High-purity, ultrafine particle size, and morphology-controlled Ta-Hf-C ceramic powder were prepared with good sintering performance, suitable for industrial production, and reduced energy consumption.
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Figure CN120622928A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of ceramic powder preparation, and in particular relates to a method for preparing Ta-Hf-C ceramic powder by combining solvent thermal treatment with a carbothermal reduction method. Background Art
[0002] Ultra-high temperature ceramics (UHTC) are ceramic compounds with a melting point above 3000°C. They can maintain mechanical and chemical stability at high temperatures, making them the most promising material for manufacturing rocket engine nozzle throat liners.
[0003] Ta-Hf-C ceramics (Ta4HfC5, TaHfC2, TaHf3C4, TaHf4C5) have comprehensive properties such as high melting point, high modulus, high hardness, and good resistance to oxidation ablation and oxidation erosion. Therefore, they have become one of the best ultra-high temperature ceramic materials for extreme service environments such as hypersonic aircraft, solid rocket engine throat liners and nozzles.
[0004] Ta-Hf-C ceramics have a high melting point. Due to the interaction of metallic bonds, ionic bonds, and covalent bonds, the self-diffusion rate of Ta-Hf-C ceramics is low, and Ta-Hf-C ceramic powders are difficult to densify during sintering. Therefore, the low degree of densification has become an important factor limiting the widespread application of Ta-Hf-C ceramic materials. For Ta-Hf-C ceramics, the sintering speed and densification degree of Ta-Hf-C ceramics can be improved by reducing the particle size and increasing the surface energy of the particles. Studies have also shown that ultrafine Ta-Hf-C ceramic powders with particle sizes ranging from hundreds of nanometers to submicron (submicron refers to particle diameters of 100nm to 1000nm) have high sintering activity, which can significantly reduce the sintering temperature of the powder and improve the theoretical density of ceramic components. However, in the existing technology, the synthesis of ultrafine high-purity Ta-Hf-C ceramic ultra-high temperature ceramic powder is difficult, and generally has defects such as complex process, high energy consumption, and difficulty in industrialization. Moreover, it is difficult to take into account both the high purity and ultrafine particle size of the powder during the production process. Summary of the Invention
[0005] In response to the above-mentioned shortcomings in the prior art, the present invention provides a method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction. This method not only has a simple process, high production efficiency, and low energy consumption, making it suitable for industrial large-scale production applications, but also the prepared Ta-Hf-C ceramic powder has high purity and ultrafine particle size, controllable morphology, and good sintering performance.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction, comprising the following steps:
[0007] Step A: Mixing acetylacetone and an alcohol solvent in a water bath and stirring to obtain a mixed solution 1, wherein the acetylacetone accounts for 20 to 30% of the total volume of the mixed solution 1;
[0008] Step B, adding TaCl5 and HfCl4 in a molar ratio of 1:4 to 4:1 to the mixed solution 1, stirring and dissolving, thereby obtaining a mixed solution 2, wherein the ratio of the total molar number of TaCl5 and HfCl4 to acetylacetone is 1 mol: (200 to 220) ml;
[0009] Step C, mixing and stirring the phenolic resin and the alcohol solvent in a water bath to obtain a mixed solution 3; the ratio of the total molar number of TaCl5 and HfCl4 to the phenolic resin in step B is 1 mol: (80-100) g;
[0010] Step D: slowly adding the mixed solution 2 dropwise to the mixed solution 3 under water bath conditions and stirring uniformly to obtain the mixed solution 4;
[0011] Step E: subjecting the mixed solution 4 to a hydrothermal reaction vessel heat treatment to obtain a precursor;
[0012] Step F, drying and grinding the precursor to obtain precursor powder;
[0013] Step G: placing the precursor powder in a tube furnace, introducing a protective gas into the tube furnace, and calcining the precursor powder at 1400-1700° C. for 60-120 minutes to obtain Ta-Hf-C ceramic powder.
[0014] As a further improvement of the method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction:
[0015] Preferably, in step A, the water bath temperature is 20-30° C., and the stirring speed is 100-800 rpm.
[0016] Preferably, in step B, after adding TaCl5 and HfCl4, the stirring speed is 100-800 rpm and the stirring time is 30-40 min.
[0017] Preferably, in step C, the water bath temperature is 70-80° C., stirring is continued for 30-40 min, and the stirring speed is 100-800 rpm.
[0018] Preferably, in step D, the mixed solution 2 is dripped into the mixed solution 3 dropwise at a rate of 1 to 10 mL / min.
[0019] Preferably, in step D, after the mixed solution 2 is added dropwise, stirring is continued for 70 to 80 minutes at a water bath temperature of 70 to 80° C. and a stirring speed of 100 to 800 rpm.
[0020] Preferably, in step E, a hydrothermal reactor is used for heat treatment, the heat treatment temperature is 180-200° C., and the insulation time is 18-24 hours.
[0021] Preferably, in step E, the volume of the mixed liquid 4 accounts for 40-50% of the volume of the hydrothermal reactor.
[0022] Preferably, in step F, the drying temperature is 60-80° C., and the drying time is 24-36 hours.
[0023] Preferably, in step G, the protective gas is argon, and the air flow rate of the protective gas is 0.005 to 50 liters / minute.
[0024] The beneficial effects of the present invention compared to the prior art are:
[0025] (1) It can be seen from the technical solution provided by the present invention that the method for preparing Ta-Hf-C ceramic powder provided by the present invention adopts HfCl4, TaCl5, alcohol solvent and acetylacetone to make a solution, then the solution is subjected to solvent heat treatment to make a precursor, the precursor is dried and ground to obtain a precursor powder, and then the precursor powder is calcined at 1400-1700°C for 60-120 minutes, so that a submicron-level (submicron-level refers to a particle size diameter of 100nm-1000nm) high-purity Ta-Hf-C ceramic powder with good sintering performance can be obtained, and by adjusting the molar ratio of the metal chloride in the mixed solution, the morphology of the Ta-Hf-C ceramic nanopowder finally obtained can be controlled. It can be seen that the present invention can not only prepare Ta-Hf-C ceramic nanopowder with high purity, ultrafine particle size, controllable morphology and good sintering performance, but also has a simple process, high production efficiency and low energy consumption, and is suitable for industrial production applications. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0027] Figure 1 This is the X-ray diffraction pattern of the Ta-Hf-C ceramic powder prepared in Example 1, Example 2, Example 3, and Example 4 of the present invention.
[0028] Figure 2 This is a scanning electron microscope photograph of the Ta-Hf-C ceramic powder prepared in Example 1 of the present invention.
[0029] Figure 3This is a transmission electron microscope photograph of the Ta-Hf-C ceramic powder prepared in Example 1 of the present invention.
[0030] Figure 4 This is a scanning electron microscope photograph of the Ta-Hf-C ceramic powder prepared in Example 2 of the present invention.
[0031] Figure 5 This is a transmission electron microscope photograph of the Ta-Hf-C ceramic powder prepared in Example 2 of the present invention.
[0032] Figure 6 This is a scanning electron microscope photograph of the Ta-Hf-C ceramic powder prepared in Example 3 of the present invention.
[0033] Figure 7 This is a transmission electron microscope photograph of the Ta-Hf-C ceramic powder prepared in Example 3 of the present invention.
[0034] Figure 8 This is a scanning electron microscope photograph of the Ta-Hf-C ceramic powder prepared in Example 4 of the present invention.
[0035] Figure 9 This is a transmission electron microscope photograph of the Ta-Hf-C ceramic powder prepared in Example 4 of the present invention. DETAILED DESCRIPTION
[0036] The following is a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.
[0037] The following is a detailed description of the method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction provided by the present invention. The contents not described in detail in the embodiments of the present invention belong to the prior art known to professionals in this field.
[0038] In order to more clearly demonstrate the technical solution and technical effects provided by the present invention, the method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction provided in an embodiment of the present invention is described in detail below with reference to specific examples.
[0039] Example 1
[0040] This embodiment provides a method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction, wherein the atomic ratio of Ta to Hf is 4:1, comprising the following steps:
[0041] Step A: In a 30° C. water bath, 2.5 ml of acetylacetone and 10 ml of anhydrous ethanol were mixed and stirred at 800 rpm to obtain a mixed solution 1, wherein the acetylacetone accounted for 20% of the total volume of the mixed solution 1;
[0042] Step B: Add 3.582 g of TaCl5 and 0.8 g of HfCl4 to the mixed solution 1 at a molar ratio of 4:1, stir and dissolve, thereby obtaining a mixed solution 2, wherein the ratio of the total molar number of TaCl5 and HfCl4 to acetylacetone is 1 mol:200 ml;
[0043] Step C: Mix 1 g of phenolic resin with 10 ml of anhydrous ethanol in an 80° C. water bath to obtain a mixed solution 3; the ratio of the total molar number of TaCl 5 and HfCl 4 to the phenolic resin in step B is 1 mol:80 g;
[0044] Step D: In a 70°C water bath, slowly add the mixed solution 2 dropwise to the mixed solution 3 at a rate of 10 mL / min and stir for 70 min until uniform at a stirring speed of 100 rpm to obtain a mixed solution 4;
[0045] Step E: Heat-treating the mixed solution 4 in a 200° C. oven using a hydrothermal reactor, with the volume of the mixed solution 4 accounting for 45% of the volume of the hydrothermal reactor, for 20 hours to obtain a Ta-Hf-C precursor;
[0046] Step F, drying the precursor in an oven at 80° C. for 30 hours and then grinding to obtain a precursor powder;
[0047] Step G: placing the precursor powder in a tube furnace, introducing argon as a protective gas into the tube furnace at a flow rate of 0.25 L / min, and calcining at 1500° C. for 80 minutes to obtain Ta-Hf-C ceramic powder.
[0048] Example 2
[0049] This embodiment provides a method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction, wherein the atomic ratio of Ta to Hf is 1:1, and the method may include the following steps:
[0050] Step A: In a water bath at 20° C., 5.5 ml of acetylacetone and 20 ml of anhydrous ethanol were mixed and stirred at 100 rpm to obtain a mixed solution 1, wherein the acetylacetone accounted for 21.5% of the total volume of the mixed solution 1;
[0051] Step B: Add 3.582 g of TaCl5 and 3.203 g of HfCl4 to the mixed solution 1 in a molar ratio of 1:1, stir and dissolve, thereby obtaining a mixed solution 2, wherein the ratio of the total moles of TaCl5 and HfCl4 to acetylacetone is 1 mol:200 ml;
[0052] Step C: Add 2 g of phenolic resin to 20 ml of anhydrous ethanol in a 70° C. water bath and mix to obtain a mixed solution 3; the ratio of the total molar number of TaCl 5 and HfCl 4 to the phenolic resin in step B is 1 mol:80 g;
[0053] Step D: In a 75°C water bath, slowly add the mixture 2 dropwise to the mixture 3 at a rate of 1 mL / min and stir for 75 min until uniform at a stirring speed of 800 rpm to obtain a mixture 4;
[0054] Step E: Heat-treating the mixed solution 4 in a 190° C. oven using a hydrothermal reactor, with the volume of the mixed solution 4 accounting for 40% of the volume of the hydrothermal reactor, for 20 h to obtain a Ta—Hf—C precursor;
[0055] Step F, drying the precursor in an oven at 70° C. for 36 hours and then grinding to obtain a precursor powder;
[0056] Step G: placing the precursor powder in a tube furnace, introducing argon as a protective gas into the tube furnace at a flow rate of 0.25 L / min, and calcining at 1600° C. for 80 minutes to obtain Ta-Hf-C ceramic powder.
[0057] Example 3
[0058] This embodiment provides a method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction, wherein the atomic ratio of Ta to Hf is 1:3, and the method may include the following steps:
[0059] Step A: In a water bath at 25° C., 5 ml of acetylacetone and 20 ml of anhydrous ethanol were mixed and stirred at 500 rpm to obtain a mixed solution 1, wherein the acetylacetone accounted for 20% of the total volume of the mixed solution 1;
[0060] Step B: Add 1.791 g of TaCl5 and 4.805 g of HfCl4 to the mixed solution 1 in a molar ratio of 1:3, stir and dissolve, thereby obtaining a mixed solution 2, wherein the ratio of the total molar number of TaCl5 and HfCl4 to acetylacetone is 1 mol:200 ml;
[0061] Step C: Add 1.6 g of phenolic resin to 20 ml of anhydrous ethanol in a 70° C. water bath and stir to obtain a mixed solution 3; the ratio of the total molar number of TaCl 5 and HfCl 4 to the phenolic resin in step B is 1 mol:80 g;
[0062] Step D: In a 70°C water bath, slowly add the mixed solution 2 dropwise to the mixed solution 3 at a rate of 10 mL / min and stir for 70 min until uniform at a stirring speed of 300 rpm to obtain a mixed solution 4;
[0063] Step E: Heat-treating the mixed solution 4 in a 180° C. oven using a hydrothermal reactor, with the volume of the mixed solution 4 accounting for 50% of the volume of the hydrothermal reactor, for 24 hours to obtain a Ta—Hf—C precursor;
[0064] Step F, drying the precursor in an oven at 70° C. for 30 hours and then grinding to obtain a precursor powder;
[0065] Step G: placing the precursor powder in a tube furnace, introducing argon as a protective gas into the tube furnace at a flow rate of 0.25 L / min, and calcining at 1600° C. for 120 minutes to obtain Ta-Hf-C ceramic powder.
[0066] Example 4
[0067] This embodiment provides a method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction, wherein the atomic ratio of Ta to Hf is 1:4, and the method may include the following steps:
[0068] Step A: In a 30° C. water bath, 5 ml of acetylacetone and 20 ml of anhydrous ethanol were mixed and stirred at 500 rpm to obtain a mixed solution 1, wherein the acetylacetone accounted for 20% of the total volume of the mixed solution 1;
[0069] Step B: Add 1.791 g of TaCl5 and 6.406 g of HfCl4 to the mixed solution 1 in a molar ratio of 1:4, stir and dissolve, thereby obtaining a mixed solution 2, wherein the ratio of the total molar number of TaCl5 and HfCl4 to acetylacetone is 1 mol:200 ml;
[0070] Step C: Add 2 g of phenolic resin to 20 ml of anhydrous ethanol in a 70° C. water bath and mix to obtain a mixed solution 3; the ratio of the total molar number of TaCl 5 and HfCl 4 to the phenolic resin in step B is 1 mol:80 g;
[0071] Step D: In a 70° C. water bath, slowly add the mixture 2 dropwise to the mixture 3 at a rate of 5 mL / min and stir for 80 min until uniform at a stirring speed of 500 rpm to obtain a mixture 4;
[0072] Step E: Heat-treating the mixed solution 4 in a 200° C. oven using a hydrothermal reactor, with the volume of the mixed solution 4 accounting for 45% of the volume of the hydrothermal reactor, for 24 hours to obtain a Ta-Hf-C precursor;
[0073] Step F, drying the precursor in an oven at 80° C. for 24 hours and then grinding to obtain a precursor powder;
[0074] Step G: placing the precursor powder in a tube furnace, introducing argon as a protective gas into the tube furnace at a flow rate of 0.25 L / min, and calcining at 1700° C. for 60 minutes to obtain Ta-Hf-C ceramic powder.
[0075] Morphology and purity testing
[0076] (1) X-ray diffraction analyzer was used to perform material detection on the Ta-Hf-C ceramic powders prepared in Example 1, Example 2, Example 3 and Example 4 of the present invention, thereby obtaining the following: Figure 1 As shown in the X-ray diffraction pattern, it can be seen from the figure that Examples 1, 2, 3 and 4 of the present invention have successfully prepared Ta-Hf-C ceramic powders with high purity.
[0077] (2) The Ta-Hf-C ceramic powders prepared in Example 1, Example 2, Example 3 and Example 4 of the present invention were observed using a scanning electron microscope, and the following were obtained: Figure 2-9 Scanning electron micrographs and transmission electron micrographs are shown.
[0078] Figure 2 This is a scanning electron microscope photo of the Ta-Hf-C ceramic powder obtained in Example 1 of the present invention. Figure 2 It can be seen that the microstructure of the Ta—Hf—C ceramic powder prepared in Example 1 of the present invention is granular, and the particle size is relatively uniform, about 50 nm.
[0079] Figure 3 This is a transmission electron microscope photo of the Ta-Hf-C ceramic powder obtained in Example 1 of the present invention. Figure 3 The Ta4HfC5 powder prepared by the present invention exhibits a nearly spherical shape and a uniform particle size distribution, primarily concentrated in the 50-60 nm range. The particles are well dispersed and lack significant hard agglomerates. This helps reduce sintering activation energy, promotes low-temperature densification, and effectively inhibits grain coarsening in the sintered body. Furthermore, TEM-EDS elemental mapping results confirm that Ta, Hf, and C exhibit highly uniform distribution within and between the powder particles, with no apparent Ta or Hf segregation zones observed.
[0080] Figure 4 This is a scanning electron microscope photo of the Ta-Hf-C ceramic powder obtained in Example 2 of the present invention. Figure 3 It can be seen that the microstructure of the Ta—Hf—C ceramic powders prepared in Example 2 of the present invention are all granular, and the particle size is relatively uniform, about 100 nm.
[0081] Figure 5 This is a transmission electron microscope photo of the Ta-Hf-C ceramic powder obtained in Example 2 of the present invention. Figure 5 The TaHfC2 powder prepared by the present invention is nearly spherical, with a uniform particle size distribution primarily concentrated in the 30-40 nm range. The particles are well dispersed and lack significant hard agglomerates. This helps reduce sintering activation energy, promotes low-temperature densification, and effectively inhibits grain coarsening in the sintered body. Furthermore, TEM-EDS elemental mapping results confirm that Ta, Hf, and C are highly uniformly distributed within and between the powder particles, with no apparent Ta or Hf segregation zones observed.
[0082] Figure 6 This is a scanning electron microscope photo of the Ta-Hf-C ceramic powder obtained in Example 3 of the present invention. Figure 4 It can be seen that the microstructure of the Ta—Hf—C ceramic powders prepared in Example 2 of the present invention are all granular, and the particle size is relatively uniform, about 100 nm.
[0083] Figure 7 This is a transmission electron microscope photo of the Ta-Hf-C ceramic powder obtained in Example 3 of the present invention. Figure 7 The TaHf3C4 powder prepared by the present invention exhibits a nearly spherical shape and a uniform particle size distribution, primarily concentrated in the 40-50 nm range. The particles are well dispersed and lack significant hard agglomerates. This helps reduce sintering activation energy, promotes low-temperature densification, and effectively inhibits grain coarsening in the sintered body. Furthermore, TEM-EDS elemental mapping results confirm that Ta, Hf, and C are highly uniformly distributed within and between the powder particles, with no apparent Ta or Hf segregation zones observed.
[0084] Figure 8 This is a scanning electron microscope photo of the Ta-Hf-C ceramic powder obtained in Example 4 of the present invention. Figure 5 It can be seen that the microstructure of the Ta-Hf-C ceramic powder produced in Example 4 of the present invention is granular, and the particle size is relatively uniform, approximately 100 nm. This shows that by adjusting the ratio of TaCl5 to HfCl4 in the mixed solution, the present embodiment can effectively adjust the type of Ta-Hf-C ceramic nanopowder produced, and the powder particle size is extremely fine.
[0085] Figure 9 This is a transmission electron microscope photo of the Ta-Hf-C ceramic powder obtained in Example 4 of the present invention. Figure 9The TaHf4C5 powder prepared by the present invention exhibits a nearly spherical shape and a uniform particle size distribution, primarily concentrated in the 50-60 nm range. The particles are well dispersed and lack significant hard agglomerates. This helps reduce sintering activation energy, promotes low-temperature densification, and effectively inhibits grain coarsening in the sintered body. Furthermore, TEM-EDS elemental mapping results confirm that Ta, Hf, and C are highly uniformly distributed within and between the powder particles, with no apparent Ta or Hf segregation zones observed.
[0086] In summary, the embodiments of the present invention not only have a simple process, high production efficiency, and low energy consumption, and are suitable for industrial large-scale production applications, but also the prepared Ta-Hf-C ceramic powder has high purity and ultrafine particle size, controllable morphology, and good sintering performance.
[0087] Those skilled in the art will appreciate that the foregoing descriptions are merely specific embodiments of the present invention, and not exhaustive. It should be noted that numerous variations and modifications are possible for those skilled in the art, and all such variations and modifications that do not exceed the scope of the claims should be considered within the scope of protection of the present invention.
Claims
1. A method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction, characterized in that: The following steps are involved: Step A: Mixing acetylacetone and an alcohol solvent in a water bath and stirring to obtain a mixed solution 1, wherein the acetylacetone accounts for 20 to 30% of the total volume of the mixed solution 1; Step B, adding TaCl5 and HfCl4 in a molar ratio of 1:4 to 4:1 to the mixed solution 1, stirring and dissolving, thereby obtaining a mixed solution 2, wherein the ratio of the total molar number of TaCl5 and HfCl4 to acetylacetone is 1 mol: (200 to 220) ml; Step C, mixing and stirring the phenolic resin and the alcohol solvent in a water bath to obtain a mixed solution 3; the ratio of the total molar number of TaCl5 and HfCl4 to the phenolic resin in step B is 1 mol: (80-100) g; Step D: slowly adding the mixed solution 2 dropwise to the mixed solution 3 under water bath conditions and stirring uniformly to obtain the mixed solution 4; Step E: subjecting the mixed solution 4 to a hydrothermal reaction vessel heat treatment to obtain a precursor; Step F, drying and grinding the precursor to obtain precursor powder; Step G: placing the precursor powder in a tube furnace, introducing a protective gas into the tube furnace, and calcining the precursor powder at 1400-1700° C. for 60-120 minutes to obtain Ta-Hf-C ceramic powder.
2. The method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction according to claim 1, characterized in that: In step A, the water bath temperature is 20-30° C., and the stirring speed is 100-800 rpm.
3. The method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction according to claim 1, characterized in that: In step B, after adding TaCl5 and HfCl4, the stirring speed is 100-800 rpm and the stirring time is 30-40 min.
4. The method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction according to claim 1, characterized in that: In step C, the water bath temperature is 70-80° C., stirring is continued for 30-40 minutes, and the stirring speed is 100-800 rpm.
5. The method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction according to claim 1 or 2, characterized in that: In step D, the mixed solution 2 is added dropwise into the mixed solution 3 at a rate of 1 to 10 mL / min.
6. The method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction according to claim 1, characterized in that: In step D, after the mixed solution 2 is added dropwise, stirring is continued for 70 to 80 minutes at a water bath temperature of 70 to 80° C. and a stirring speed of 100 to 800 rpm.
7. The method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction according to claim 1, characterized in that: In step E, a hydrothermal reactor is used for heat treatment, the heat treatment temperature is 180-200° C., and the insulation time is 18-24 hours.
8. The method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction according to claim 1, characterized in that: In step E, the volume of the mixed liquid 4 accounts for 40-50% of the volume of the hydrothermal reactor.
9. The method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction according to claim 1, characterized in that: In step F, the drying temperature is 60-80° C., and the drying time is 24-36 hours.
10. The method for preparing Ta-Hf-C ceramic powder by solvent thermal treatment combined with carbothermal reduction according to claim 1, characterized in that: In step G, the protective gas is argon, and the air flow rate of the protective gas is 0.005 to 50 L / min.