A method for preparing a tantalum carbide powder

Abstract

This invention discloses a method for preparing tantalum carbide powder, belonging to the field of structural ceramics technology. The method includes the following steps: S1, mixing glucose monohydrate, tantalum pentoxide, and water, heating and stirring in a water bath, then adding an organic monomer, crosslinking agent, and catalyst to obtain a mixed gel; S2, subjecting the mixed gel obtained in step S1 to segmented high-temperature treatment: holding at 80℃ for 24 hours, at 100℃ for 24 hours, at 120℃ for 12 hours, at 146℃ for 4 hours, at 180℃ for 4 hours, and at 200℃ for 4 hours; S3, placing the mixed gel treated in step S2 into a crucible for segmented high-temperature treatment, followed by furnace cooling to obtain tantalum carbide powder. The TaC ceramic powder prepared by this invention has small grain size, uniform particle size distribution, and high purity. The preparation method is simple, efficient, environmentally friendly, and safe.

Description

Technical Field

[0001] This invention belongs to the field of structural ceramics technology, specifically relating to a method for preparing tantalum carbide powder. Background Technology

[0002] TaC ceramics are the most metallic refractory metal carbide ceramics formed from Group IV and V elements, with a melting point reaching 3880℃. They possess excellent properties such as high strength, hardness, wear resistance, and high elastic modulus (477–560 GPa). Their crystal lattice structure is NaCl-type, and the strong covalent-metallic bonding gives them good resistance to oxidation and chemical corrosion.

[0003] TaC ceramics are widely used in military and industrial fields due to their excellent properties. In the aerospace industry, TaC is used as an ultra-high temperature coating material in critical components such as aircraft nose cones, wing leading edges, and engine hot sections to insulate against high temperatures. For example, a TaC coating is added to the C / C composite material of rocket engine nozzles to reduce the ablation rate of the C / C composite material. In the manufacture of cutting tools, TaC coatings are often added to the surface of the base metal to significantly improve its corrosion resistance and wear resistance. In addition, TaC ceramics also possess excellent optical and electrical properties, and can be used as optical coatings and electrical contact materials.

[0004] The reliability of TaC ceramic components relies on their high density. However, the high temperatures during the preparation process can cause TaC powder grain growth, affecting the densification process of the ceramic bulk and leading to a decrease in the mechanical properties of the ceramic components. Currently, the key to improving the sintering performance of TaC ceramics is to adopt appropriate synthesis methods to prepare TaC ceramic powder with small grain size, uniform particle size distribution, and simple composition.

[0005] The main methods for preparing TaC ceramic powder reported in the literature include: solid-state reaction method, high-temperature self-propagating synthesis method, sol-gel method, molten salt-assisted carbothermic reduction method, and precursor conversion method. Wu et al. reduced Ta2O5 powder under vacuum conditions with excess carbon black, then removed free carbon with Ca powder, and finally obtained TaC ceramic powder with an average particle size of 120 nm after acid washing. This method is low-cost, high-yield, and simple, but the sintering of the raw material powder and grain growth during the high-temperature solid-state reaction leads to a decrease in product performance. VGSevast'yanov et al. used Ta-C gel and obtained TaC ceramic powder with a particle size of 30 nm by pyrolysis at 1200℃. The ceramic powder obtained by this method has fine grains and a simple composition, but the reaction preparation cycle is long, the required raw materials are mostly organic, which are highly toxic and costly, making it unsuitable for mass production. Yan Shuai et al. synthesized TaC ceramic powder using Ta2O5 as the tantalum source, phenolic resin as the carbon source, and NaCl-NaF as the molten salt medium. Molten salt assistance accelerates the diffusion rate of reactants and effectively inhibits grain growth. The powder prepared by this method has a smaller particle size, but molten salt is toxic, and intermediate products are present during the reaction, resulting in low purity of ceramic powder.

[0006] Existing technologies have drawbacks such as low purity of ceramic products, long preparation cycles, and expensive raw materials. Summary of the Invention

[0007] The problem to be solved by the present invention is to provide a method for preparing tantalum carbide powder, which overcomes the problems of large particle size and low purity of ceramic products obtained by the existing technology. The prepared TaC ceramic powder has small grain size, uniform particle size distribution and high purity. The preparation method is simple to operate, efficient, environmentally friendly and safe, and has low raw material cost.

[0008] The present invention includes a method for preparing tantalum carbide powder, comprising the following steps:

[0009] S1. Glucose monohydrate, tantalum pentoxide and water are mixed, heated and stirred in a water bath, and then organic monomers, crosslinking agents and catalysts are added to obtain a mixed gel.

[0010] S2. Perform segmented heat preservation treatment on the mixed gel obtained in step S1: heat preservation at 80℃ for 24h, heat preservation at 100℃ for 24h, heat preservation at 120℃ for 12h, heat preservation at 146℃ for 4h, heat preservation at 180℃ for 4h, and heat preservation at 200℃ for 4h.

[0011] S3. The mixed gel after step S2 is placed in a crucible for segmented high-temperature treatment. After cooling in the furnace, tantalum carbide powder is obtained.

[0012] Furthermore, in step S1, the raw materials are mixed in a beaker, and in step S2, the beaker is placed in an electric heating drying oven for segmented heat preservation treatment, and the heat resistance temperature of the beaker is above 200℃.

[0013] Furthermore, the total amount of glucose monohydrate and tantalum pentoxide is 1 / 3 to 2 / 3 of the volume of the beaker.

[0014] Furthermore, in step S1, the organic monomer is acrylamide monomer, the crosslinking agent is N,N'-methylenediacrylamide, and the catalyst is a mixture of ammonium persulfate and tetramethylethylenediamine.

[0015] Furthermore, the mass ratio of acrylamide monomer to N,N'-methylene dipolyacrylamide is (30-35):1.

[0016] Furthermore, the mass ratio of ammonium persulfate to tetramethylethylenediamine is (0.1–0.14):1.

[0017] Furthermore, in step S1, the mass ratio of glucose monohydrate to water is (1.8 to 2.2):1.

[0018] Furthermore, in step S1, the mass ratio of tantalum pentoxide to glucose monohydrate is (0.7–1.9):1.

[0019] Furthermore, in step S1, the mass ratio of tantalum pentoxide to glucose monohydrate is (0.7-1.6):1.

[0020] Furthermore, in step S3, the segmented high-temperature treatment process includes: heating to 1200-1500°C at a heating rate of 10°C / min under Ar atmosphere or vacuum conditions, and holding at that temperature for 2-3 hours.

[0021] The beneficial effects of this invention are:

[0022] This invention utilizes the pyrolysis property of glucose at high temperatures to decompose glucose into highly active solid carbon elemental by raising the temperature. Compared with carbon black used in traditional industrial production, glucose easily forms fine carbon particles during carbonization and decomposition, which have a large specific surface area and higher activity, which is beneficial to the synthesis of ultrafine TaC powder. At the same time, compared with other highly toxic organic carbon sources, glucose is low in cost and non-toxic and pollution-free.

[0023] This invention employs a gelation process, which allows for more uniform mixing of glucose and tantalum pentoxide, shortens the atomic diffusion distance during the redox reaction, helps lower the reaction temperature, avoids incomplete reaction caused by uneven powder mixing, and ensures more complete carbothermic reduction reaction, thereby improving product purity. During the research process, it was discovered that glucose undergoes pyrolysis during heating, producing small organic molecules that leave the reaction system, resulting in low carbon utilization. This invention addresses this by using a gelation method to fix carbon and performing segmented heat preservation treatment, increasing the carbon retention rate from 17.1% to 80-90%, thus improving carbon utilization. During the segmented heat treatment stage, a slow-then-fast heating rate was adopted to remove as much free water as possible from the glucose hydrogel system and stabilize the gel structure. The system was kept at a lower temperature of 100℃ for 24 hours and then at 120℃ for 12 hours to prevent the unstable gel structure from breaking down and causing sugar foaming. The weight loss of the hydrogel in this stage mainly comes from the evaporation of free water and the dehydration and degradation of sugar caramelization. Subsequently, the system was kept at 146℃, 180℃, and 200℃ for 4 hours each. The 146℃ temperature further dehydrates the gel, increases viscosity, reduces osmotic pressure, and stabilizes the gel structure. 180℃ is the caramelization point of sugars, at which temperature the sol-gel system gradually solidifies. Finally, the gel is completely solidified at 200℃.

[0024] The TaC ceramic powder prepared by this invention has a grain size of 40-70 nm and a particle size of 100-600 nm. It has small grain size, uniform particle size distribution, and high purity. The preparation method is simple, efficient, environmentally friendly and safe. Attached Figure Description

[0025] Appendix Figure 1 This is a process flow diagram for preparing TaC ceramic powder according to an embodiment of the present invention;

[0026] Appendix Figure 2 The X-ray diffraction pattern of the TaC ceramic powder prepared in Example 1 is shown, where the intensity of the vertical axis is in cps and the diffraction angle of the horizontal axis is in °.

[0027] Appendix Figure 3 This is a scanning electron microscope image of the TaC ceramic powder prepared in Example 1;

[0028] Appendix Figure 4 The X-ray diffraction pattern of the TaC ceramic powder prepared in Example 2 is shown, where the intensity of the vertical axis is in cps and the diffraction angle of the horizontal axis is in °.

[0029] Appendix Figure 5 This is a scanning electron microscope image of the TaC ceramic powder prepared in Example 2;

[0030] Appendix Figure 6The X-ray diffraction pattern of the TaC ceramic powder prepared in Example 3 is shown, where the intensity of the vertical axis is in cps and the diffraction angle of the horizontal axis is in °.

[0031] Appendix Figure 7 This is a scanning electron microscope image of the TaC ceramic powder prepared in Example 3;

[0032] Appendix Figure 8 The X-ray diffraction pattern of the TaC ceramic powder prepared in Example 4 is shown, where the intensity on the vertical axis is in cps and the diffraction angle on the horizontal axis is in °.

[0033] Appendix Figure 9 This is a scanning electron microscope image of the TaC ceramic powder prepared in Example 4;

[0034] Appendix Figure 10 The X-ray diffraction pattern of the TaC ceramic powder prepared in Example 5 is shown, where the intensity of the vertical axis is in cps and the diffraction angle of the horizontal axis is in °.

[0035] Appendix Figure 11 This is a scanning electron microscope image of the TaC ceramic powder prepared in Example 5;

[0036] Appendix Figure 12 The X-ray diffraction pattern of the TaC ceramic powder prepared in Example 6 is shown, where the intensity of the vertical axis is in cps and the diffraction angle of the horizontal axis is in °.

[0037] Appendix Figure 13 This is a scanning electron microscope image of the TaC ceramic powder prepared in Example 6;

[0038] Appendix Figure 14 The X-ray diffraction pattern of the TaC ceramic powder prepared in Comparative Example 1 is shown, where the intensity of the vertical axis is in cps and the diffraction angle of the horizontal axis is in °.

[0039] Appendix Figure 15 Here is a scanning electron microscope image of the TaC ceramic powder prepared in Comparative Example 1;

[0040] Appendix Figure 16 The X-ray diffraction pattern of the TaC ceramic powder prepared in Comparative Example 2 is shown, where the intensity of the vertical axis is in cps and the diffraction angle of the horizontal axis is in °.

[0041] Appendix Figure 17 Here is a scanning electron microscope image of the TaC ceramic powder prepared in Comparative Example 2;

[0042] Appendix Figure 18 The X-ray diffraction pattern of the TaC ceramic powder prepared in Comparative Example 3 is shown, where the intensity of the vertical axis is in cps and the diffraction angle of the horizontal axis is in °.

[0043] Appendix Figure 19 Here is a scanning electron microscope image of the TaC ceramic powder prepared in Comparative Example 3;

[0044] Appendix Figure 20 The X-ray diffraction pattern of the TaC ceramic powder prepared in Comparative Example 4 is shown, where the intensity of the vertical axis is in cps and the diffraction angle of the horizontal axis is in °.

[0045] Appendix Figure 21 Here is a scanning electron microscope image of the TaC ceramic powder prepared in Comparative Example 4;

[0046] Appendix Figure 22 The X-ray diffraction pattern of the TaC ceramic powder prepared in Comparative Example 5 is shown, where the intensity on the vertical axis is in cps and the diffraction angle on the horizontal axis is in °.

[0047] Appendix Figure 23 Here is a scanning electron microscope image of the TaC ceramic powder prepared in Comparative Example 5;

[0048] Appendix Figure 24 The X-ray diffraction pattern of the TaC ceramic powder prepared in Comparative Example 6 is shown, where the intensity of the vertical axis is in cps and the diffraction angle of the horizontal axis is in °.

[0049] Appendix Figure 25 Here is a scanning electron microscope image of the TaC ceramic powder prepared in Comparative Example 6;

[0050] Appendix Figure 26 The X-ray diffraction pattern of the TaC ceramic powder prepared in Comparative Example 7 is shown, where the intensity of the vertical axis is in cps and the diffraction angle of the horizontal axis is in °.

[0051] Appendix Figure 27 The image shows a scanning electron microscope (SEM) image of the TaC ceramic powder prepared in Comparative Example 7. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Furthermore, the technical solutions of the various embodiments of this invention can be combined with each other, but only on the basis of being achievable by one of ordinary skill in the art. When a combination of technical solutions is contradictory or impossible to implement, such a combination should be considered non-existent and not within the scope of protection claimed by this invention.

[0054] As attached Figure 1 As shown, this embodiment of the invention provides a method for preparing tantalum carbide powder, including the following steps:

[0055] S1. Glucose monohydrate, tantalum pentoxide, and water are mixed, heated and stirred in a water bath, and then organic monomers, crosslinking agents, and catalysts are added to obtain a mixed gel. Glucose serves as the carbon source, and tantalum pentoxide as the tantalum source. The carbon source is a key factor limiting the purity and particle size of the powder. Compared to carbon black used in traditional industrial production, glucose easily generates fine carbon particles during subsequent carbonization and decomposition, possessing a large specific surface area and higher activity, which is beneficial for the synthesis of ultrafine TaC powder. Furthermore, compared to other highly toxic organic carbon sources, glucose is low-cost, non-toxic, and pollution-free. The gelation process... The gel method allows for a more uniform mixing of glucose and tantalum pentoxide, shortening the atomic diffusion distance during the redox reaction. This helps to lower the reaction temperature, avoids incomplete reactions caused by uneven powder mixing, and ensures thorough mixing of reactants to guarantee a more complete subsequent carbothermic reduction reaction, thereby improving product purity. Furthermore, during heating, glucose undergoes pyrolysis to produce small organic molecules that leave the reaction system, resulting in low carbon utilization. By using the gel method to fix carbon and performing segmented heat preservation treatment, the carbon retention rate was increased from 17.1% to 80-90%, thus improving carbon utilization.

[0056] S2. The mixed gel obtained in step S1 is subjected to segmented heat treatment: heat treatment at 80℃ for 24 hours, at 100℃ for 24 hours, at 120℃ for 12 hours, at 146℃ for 4 hours, at 180℃ for 4 hours, and at 200℃ for 4 hours. This stage can solidify the gel structure and reduce carbon loss during subsequent high-temperature processes. In the segmented heat treatment stage, a slow-then-fast heating rate is adopted to remove as much free water as possible from the glucose hydrogel system, stabilize the gel structure, and prevent unstable gel structure from being broken down and causing sugar foaming. The weight loss of the hydrogel in this stage mainly comes from the evaporation of free water and the dehydration and degradation of sugars during caramelization. Afterwards, it is kept at 146℃, 180℃, and 200℃ for 4 hours each. The 146℃ temperature further dehydrates the gel, increases viscosity, reduces osmotic pressure, and stabilizes the gel structure. 180℃ is the caramelization point of sugars, at which temperature the sol-gel system gradually solidifies. Finally, the gel completely solidifies at 200℃. Below 180℃, the gel is difficult to solidify, while above 200℃, it can be completely solidified. For environmental and safety reasons, the temperature of the segmented insulation stages does not need to be set too high; considering all factors, it should not exceed 220℃.

[0057] S3. Place the mixed gel treated in step S2 into a crucible and place it in a pyrolysis furnace for segmented high-temperature treatment. After cooling with the furnace, tantalum carbide powder is obtained. In this step, glucose is pyrolyzed at high temperature and undergoes a redox reaction with tantalum pentoxide to generate tantalum carbide.

[0058] This invention utilizes the pyrolysis property of glucose at high temperatures. By raising the temperature, glucose is decomposed into highly active solid carbon. Taking advantage of the uniformity of the gel system, the carbon derived from glucose decomposition is fully mixed with tantalum pentoxide, ultimately undergoing a redox reaction to generate tantalum carbide powder with small particle size. The TaC ceramic powder has a grain size of 40-70 nm and a particle size of 100-600 nm. It has small grain size, uniform particle size distribution, and high purity. The preparation method is simple, efficient, environmentally friendly, and safe.

[0059] In a preferred embodiment, in step S1, for ease of operation, glucose monohydrate, tantalum pentoxide powder and water are added to a beaker, the beaker is placed in a water bath and stirred, and then organic monomers, crosslinking agents and catalysts are added to form a mixed gel. In step S2, the beaker is directly placed in an electric heating drying oven for segmented heat preservation treatment, requiring the beaker to have a heat resistance temperature above 200°C.

[0060] In a preferred embodiment, the total amount of glucose monohydrate and tantalum pentoxide is not less than 1 / 3 and not more than 2 / 3 of the beaker volume, ensuring that the amount used is as large as possible without causing the glucose to caramelize and overflow the beaker during the segmented heat preservation process.

[0061] In a preferred embodiment, in step S1, the organic monomer is acrylamide monomer, the crosslinking agent is N,N'-methylenediacrylamide used as the gel material, and the catalyst is a mixture of ammonium persulfate and tetramethylethylenediamine, wherein both ammonium persulfate and tetramethylethylenediamine can act as catalysts. Compared to using one of the catalysts alone, the gel solidification time is more precise, allowing for timely removal of the stirring rotor to prevent solidification within the gel.

[0062] In a preferred embodiment, the mass ratio of acrylamide monomer to N,N'-methylenediacrylamide is (20-40):1. When the monomer is in excess relative to the crosslinking agent, an "over-gelling" phenomenon occurs, with some acrylamide monomer forming a white precipitate that destroys the gel structure. When the monomer is insufficient relative to the crosslinking agent, the three-dimensional network structure of the gel is not strong enough, and cracking may occur during the segmented heat preservation process; some tantalum pentoxide powder precipitates out of the system and cannot participate in subsequent reactions, reducing the yield.

[0063] In a preferred embodiment, the mass ratio of ammonium persulfate to tetramethylethylenediamine is (0.1–0.14):1.

[0064] In a preferred embodiment, in step S1, the mass ratio of glucose monohydrate to water is (1.8-2.2):1; the mass of water affects the ease of gel formation; if the mass of water is too small, tantalum pentoxide and glucose cannot be sufficiently dispersed and mixed, and a gel cannot be formed, resulting in a large amount of unreacted carbon and tantalum pentoxide in the final product; if the mass of water is too large, the relative concentration of acrylamide decreases, the structure of the formed gel structure is relatively loose, and it cannot play a role in carbon fixation. The small molecule organic matter generated by pyrolysis will leave the reaction system, which reduces the utilization rate of carbon, and unreacted tantalum pentoxide appears in the final product.

[0065] In a preferred embodiment, in step S1, the mass ratio of tantalum pentoxide to glucose monohydrate is (0.7-1.9):1. The mass ratio of glucose monohydrate to tantalum pentoxide powder mainly determines the ratio of carbon and tantalum in the reaction system. When glucose monohydrate is insufficient, the reaction is incomplete, which will affect the purity of the product. When glucose monohydrate and tantalum pentoxide are exactly at the reaction stoichiometric ratio, some tantalum pentoxide will still not react completely. When glucose monohydrate is in appropriate excess, the reaction proceeds fully, the purity of the product is improved, and the excess carbon is conducive to the nucleation and growth of carbonized tantalum, forming finer powder.

[0066] In a preferred embodiment, in step S1, the mass ratio of tantalum pentoxide to glucose monohydrate is (0.7-1.6):1; within the mass ratio range of this embodiment, the resulting TaC ceramic powder has smaller grain size and more uniform particle size.

[0067] In a preferred embodiment, step S3, the segmented high-temperature treatment process includes: heating to 1200–1500°C at a heating rate of 10°C / min under Ar atmosphere or vacuum conditions, and holding at that temperature for 2–3 hours. Generally, the high-temperature treatment stage determines the thermodynamics and kinetics of the redox formation of tantalum carbide. From a thermodynamic perspective, the reaction temperature determines the form of the intermediate product; at higher temperatures, it exists as smaller groups, and at lower temperatures, it exists as larger groups. From a kinetic perspective, the reaction rate constant and temperature conform to the Arrhenius relation; as the reaction temperature increases… To accelerate the reaction rate, tantalum carbide was prepared by carbothermal reduction of glucose and tantalum pentoxide as reactants. When the reaction temperature was below 1200℃, unreacted tantalum pentoxide and carbon could be observed in the XRD pattern. Tantalum carbide powder and carbon black particles were found in the product, indicating that although the generated tantalum carbide had nucleated and grown grains, the reaction was incomplete. At higher temperatures, the generated tantalum carbide grains continued to grow, resulting in poorer powder dispersibility and increased particle size. When the reaction temperature was above 1500℃, the tantalum carbide powder particle size was relatively large. Regarding the holding time, both grain size and powder particle size increased with increasing holding time. When the holding time was >3h, the powder particle size continued to increase, and the sintering performance of the ceramic powder decreased. When the holding time was short (<1h), unreacted tantalum pentoxide remained in the product, reducing product purity and yield. Preferably, the segmented high-temperature treatment is carried out in an Ar atmosphere. During the high-temperature pyrolysis and redox process of glucose, gas is generated, and the temperature will rise if the gas partial pressure is too high. Choosing to pyrolyze the gel at high temperature in a high-purity Ar atmosphere is beneficial for preparing high-purity TaC ceramic powder.

[0068] Example 1

[0069] This embodiment provides a method for preparing tantalum carbide powder, including the following steps:

[0070] S1. Add glucose monohydrate, tantalum pentoxide powder, and water to a beaker. The mass ratio of glucose monohydrate to water is 2:1, and the mass ratio of tantalum pentoxide powder to glucose monohydrate is 0.7:1. Place the beaker in a water bath at 60.0℃ and add a magnetic stir bar. Stir for about 20 minutes until the suspension is homogeneous. Add acrylamide monomer and N,N'-methylenediacrylamide crosslinking agent to the suspension and stir for about 3 minutes. Add 0.008g of ammonium persulfate and stir for 2 minutes. Add 2 drops of tetramethylethylenediamine and stir for 3-5 seconds. Quickly remove the magnetic stir bar and let stand for 5 minutes.

[0071] S2. Place the beaker in an electric heating drying oven for cross-linking curing and pre-carbonization. Keep it at 80℃ for 24 hours, 100℃ for 24 hours, 120℃ for 12 hours, 146℃ for 4 hours, 180℃ for 4 hours, and 200℃ for 4 hours.

[0072] S3. The mixed gel of glucose and tantalum pentoxide is placed in a graphite crucible and subjected to segmented high-temperature treatment in a pyrolysis furnace: Under an Ar atmosphere, the graphite crucible containing the glucose and tantalum pentoxide gel is heated to 1300℃ at a heating rate of 10℃ / min, held at that temperature for 2 hours, and then cooled with the furnace to obtain tantalum carbide powder.

[0073] As attached Figure 2 and attached Figure 3 As shown, the TaC ceramic powder obtained in this embodiment has a grain size of approximately 19.5 nm and a particle size of 300–500 nm.

[0074] Example 2

[0075] In this embodiment, the temperature is raised to 1400°C in the final high-temperature treatment, and the other steps are the same as in Embodiment 1.

[0076] As attached Figure 4 and attached Figure 5 As shown, the TaC ceramic powder obtained in this embodiment has a grain size of approximately 41.0 nm and a particle size of 400–600 nm.

[0077] Example 3

[0078] In this embodiment, the mass ratio of tantalum pentoxide powder to glucose monohydrate is 0.85:1, and the temperature is raised to 1400°C in the final stage of high-temperature treatment. All other steps are the same as in Example 1.

[0079] As attached Figure 6 and attached Figure 7 As shown, the TaC ceramic powder obtained in this embodiment has a grain size of approximately 41.7 nm and a particle size of 400–600 nm.

[0080] Example 4

[0081] In this embodiment, the mass ratio of tantalum pentoxide powder to glucose monohydrate is 1.6:1, and the temperature is raised to 1400°C in the final stage of high-temperature treatment. All other steps are the same as in Example 1.

[0082] As attached Figure 8 and attached Figure 9 As shown, the TaC ceramic powder obtained in this embodiment has a grain size of approximately 44.0 nm and a particle size of 100–300 nm.

[0083] Example 5

[0084] In this embodiment, the mass ratio of tantalum pentoxide powder to glucose monohydrate is 1.7:1, and the temperature is raised to 1400°C in the final stage of high-temperature treatment. All other steps are the same as in Example 1.

[0085] As attached Figure 10 and attached Figure 11 As shown, the TaC ceramic powder obtained in this embodiment has a grain size of approximately 46.5 nm and a particle size of 200–500 nm.

[0086] Example 6

[0087] In this embodiment, the mass ratio of tantalum pentoxide powder to glucose monohydrate is 1.9:1, and the temperature is raised to 1400°C in the final stage of high-temperature treatment. All other steps are the same as in Example 1.

[0088] As attached Figure 12 and attached Figure 13 As shown, the TaC ceramic powder obtained in this embodiment has a grain size of approximately 64.7 nm and a particle size of 200–600 nm.

[0089] Comparative Example 1

[0090] In this comparative example, conventional heating methods were used for gel curing, and all other steps were the same as in Example 1.

[0091] As attached Figure 14 and attached Figure 15 As shown, the TaC ceramic powder obtained in this embodiment has a large grain size (>100nm) and cannot be calculated using the Scherrer formula; the particle size is 150-350nm.

[0092] Comparative Example 2

[0093] In this comparative example, the temperature was raised to 1100°C in the final high-temperature treatment, and all other steps were the same as in Example 1.

[0094] As attached Figure 16 and attached Figure 17 As shown, the TaC ceramic powder prepared in this embodiment contains unreacted carbon and tantalum pentoxide, and the grain size cannot be determined, but the particle size is about 400 nm.

[0095] Comparative Example 3

[0096] In this comparative example, the temperature was raised to 1600°C in the final high-temperature treatment, and all other steps were the same as in Example 1.

[0097] As attached Figure 18 and attached Figure 19 As shown, the TaC ceramic powder obtained in this embodiment has a large grain size (>100nm), and the particle size cannot be calculated to be 150-700nm using the Scherrer formula.

[0098] Comparative Example 4

[0099] In this comparative example, the mass ratio of tantalum pentoxide powder to glucose monohydrate was 0.4:1, and the temperature was raised to 1400°C in the final stage of high-temperature treatment. All other steps were the same as in Example 1.

[0100] As attached Figure 20 and attached Figure 21 As shown, the TaC ceramic powder prepared in this embodiment contains excess carbon and has a particle size of 50-150 nm.

[0101] Comparative Example 5

[0102] In this comparative example, the mass ratio of tantalum pentoxide powder to glucose monohydrate was 2.0:1, and the temperature was raised to 1400°C in the final stage of high-temperature treatment. All other steps were the same as in Example 1.

[0103] As attached Figure 22 and attached Figure 23 As shown, the TaC ceramic prepared in this embodiment contains a large amount of unreacted tantalum pentoxide, and the powder particle size is 100-400 nm.

[0104] Comparative Example 6

[0105] In this comparative example, the temperature was raised to 1400°C in the final segmented high-temperature treatment, and the holding time for the segmented high-temperature treatment was 1 hour. All other steps were the same as in Example 1.

[0106] As attached Figure 24 and attached Figure 25 As shown, the TaC ceramic powder prepared in this embodiment has a grain size of approximately 31.7 nm and a particle size of 100–200 nm. However, SEM images reveal that there are still a very small amount of unreacted carbon and tantalum pentoxide.

[0107] Comparative Example 7

[0108] In this comparative example, the temperature was raised to 1400°C in the final segmented high-temperature treatment, and the holding time for the segmented high-temperature treatment was 4 hours. All other steps were the same as in Example 1.

[0109] As attached Figure 26 and attached Figure 27 As shown, the TaC ceramic powder obtained in this embodiment has a large grain size (>100nm), which cannot be calculated using the Scherrer formula, and the particle size is 200-500nm.

[0110] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0111] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

[0112] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A method for preparing tantalum carbide powder, characterized in that, Includes the following steps: S1. Glucose monohydrate, tantalum pentoxide, and water are mixed, heated and stirred in a water bath, and then an organic monomer, a crosslinking agent, and a catalyst are added to obtain a mixed gel. The organic monomer is acrylamide monomer, the crosslinking agent is N,N'-methylenedipolyacrylamide, and the catalyst is a mixture of ammonium persulfate and tetramethylethylenediamine. The mass ratio of acrylamide monomer to N,N'-methylenedipolyacrylamide is (30~35):1; the mass ratio of ammonium persulfate to tetramethylethylenediamine is (0.1~0.14):1; and the mass ratio of tantalum pentoxide to glucose monohydrate is (0.7~1.9):

1. S2. Perform segmented heat preservation treatment on the mixed gel obtained in step S1: heat preservation at 80℃ for 24h, heat preservation at 100℃ for 24h, heat preservation at 120℃ for 12h, heat preservation at 146℃ for 4h, heat preservation at 180℃ for 4h, and heat preservation at 200℃ for 4h. S3. The mixed gel after step S2 is placed in a crucible for segmented high-temperature treatment. The segmented high-temperature treatment process includes: heating to 1200~1500℃ at a heating rate of 10℃ / min under Ar atmosphere or vacuum conditions, holding at the temperature for 2~3h, and then cooling with the furnace to obtain tantalum carbide powder.

2. The method for preparing tantalum carbide powder as described in claim 1, characterized in that, In step S1, the raw materials are placed in a beaker for mixing. In step S2, the beaker is placed in an electric heating drying oven for segmented heat preservation treatment. The heat resistance temperature of the beaker is above 200°C.

3. The method for preparing tantalum carbide powder as described in claim 2, characterized in that, The total amount of glucose monohydrate and tantalum pentoxide is 1 / 3 to 2 / 3 of the volume of the beaker.

4. The method for preparing tantalum carbide powder as described in claim 1, characterized in that, In step S1, the mass ratio of glucose monohydrate to water is (1.8~2.2):

1.

5. The method for preparing tantalum carbide powder as described in claim 1, characterized in that, In step S1, the mass ratio of tantalum pentoxide to glucose monohydrate is (0.7~1.6):1.

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