Zirconium alkoxide supramolecular zirconium carbide ceramic precursor, block zirconium carbide ceramic and preparation method thereof

Abstract

The invention belongs to the field of organic chemical materials, and particularly relates to a zirconium alkoxide supramolecular zirconium carbide ceramic precursor, block zirconium carbide ceramic and a preparation method of the zirconium alkoxide supramolecular zirconium carbide ceramic precursor. Zirconium alkoxide supramolecules are generated through reaction of a zirconium source substance and an organic matter carbon source substance, the zirconium source substance is dissolved in the carbon source substance, heat preservation is conducted, and the zirconium source substance and the block zirconium carbide ceramic react fully; the carbon source substance is a polyhydroxy organic matter; the zirconium alkoxide supramolecular viscous liquid and the zirconium carbide powder are mixed and sintered to form the block zirconium carbide ceramic, the obtained block zirconium carbide ceramic is high in compactness and purity, in the process that the zirconium alkoxide supramolecular is subjected to high-temperature treatment to generate the zirconium carbide ceramic, excessive volatilization loss of carbon atoms cannot be caused, the pure zirconium carbide ceramic can be generated without a high carbon-zirconium ratio, and the preparation method is simple and easy to implement. Meanwhile, the yield requirement is ensured; compared with a traditional zirconium carbide ceramic preparation method, the method has the advantages that the process is simple and easy to implement, high-toxicity organic solvents are not needed, the whole process is low in cost, safe and environmentally friendly, and the requirements of green chemistry are met.

Description

Technical Field

[0001] The invention belongs to the field of organic chemical materials, and in particular relates to a zirconium alkoxide supramolecular zirconium carbide ceramic precursor, a bulk zirconium carbide ceramic and a preparation method thereof. Background Art

[0002] Zirconium carbide ceramics possess excellent high-temperature resistance, outstanding mechanical properties (such as high hardness, excellent creep resistance, and fracture toughness), and unique neutron radiation resistance (effectively blocking fast neutrons and reducing secondary radiation). Therefore, they have important applications in extreme operating conditions, such as high-temperature propulsion systems in aerospace and reactor cladding materials in nuclear power generation. However, the traditional preparation process for zirconium carbide ceramics has significant limitations: the solid-state sintering process easily introduces impurities such as oxygen and nitrogen, resulting in insufficient product purity. Materials synthesized by powder metallurgy often exhibit uneven grain size distribution, and the complex process relies on high-temperature carbothermal reduction or self-propagating combustion synthesis, which is accompanied by high energy consumption and pollutant emissions. Reference 1 "Katea SN, Riekehr L, Westin G. Synthesis of nano-phase ZrC by carbothermal reduction using a ZrO2-carbon nano-composite[J]. Journal of the EuropeanCeramic Society, 2021, 41(1): 62-72" reports a method for generating zirconium carbide ceramics by high-temperature treatment of nano-zirconium dioxide powder and nano-carbon powder. The method of preparing zirconium carbide by carbon thermal reduction of zirconium dioxide usually has the limitation that the reactants are difficult to fully react and remain in the product, affecting the purity of the product. Reference 2 "Li K, Guo L, Wang Y, etal. Synthesis and thermal performance of polymer precursor for ZrC ceramic[J]. Ceramics International, 2021, 47(20): 28806-28810" reported a method of producing zirconium carbide ceramics by using zirconium oxychloride and polyvinyl alcohol as zirconium carbide ceramic precursors and high-temperature treatment. Traditional zirconium carbide ceramic precursors often have limitations such as complex preparation process, low raw material conversion rate, high toxicity and high pollution.

[0003] It can be seen that the existing zirconium carbide ceramic synthesis technology mainly relies on the solid-phase reaction of zirconium dioxide or metallic zirconium with a carbon source. This process has significant limitations: First, the large particle size of the solid raw materials leads to a limited contact interface, which blocks the atomic migration channel in the reaction system and makes it difficult to achieve uniform interdiffusion of zirconium and carbon elements. Second, the sluggish kinetics of the heterogeneous reaction leads to incomplete lattice reconstruction at high temperatures. The final product often contains unconverted zirconium dioxide phases due to incomplete reaction in local areas. Third, microscopic compositional segregation can trigger the formation of grain boundary impurity phases within the ceramic body, directly affecting the structural integrity and performance stability of the material. Based on this, the development of zirconium alkoxide supramolecular precursor synthesis technology can break through the bottleneck of traditional processes. By constructing a homogeneous zirconium-carbon system through molecular-level coordination, it fundamentally eliminates the diffusion barrier at the heterogeneous interface and provides an innovative solution for the preparation of high-purity, low-defect zirconium carbide ceramics. This will have a dual driving effect on the development of ceramic material preparation science and application technology. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a method using zirconium alkoxide supramolecules as zirconium carbide precursors, which aims to solve the difficulties in synthesizing existing zirconium carbide ceramics, the difficulty in preparing uniform and pure products, and the limitations of existing zirconium carbide precursors in achieving safety, environmental protection, high conversion rate, and low production cost.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a zirconium alkoxide supramolecular zirconium carbide ceramic precursor is produced by the reaction of polyhydroxy organic matter as a carbon source and zirconium-containing salts as a zirconium source, and the internal structure is a network structure. The zirconium atoms and polyol ligands are combined through coordination bonds to form zirconium alkoxide molecules with a complex skeleton structure. The zirconium alkoxide molecules with a complex skeleton structure are further cross-linked through hydrogen bonds between hydroxyl groups to form a polymer network structure. This method constructs a three-dimensional network structure through the synergistic effect of coordination bonds and hydrogen bonds at the molecular scale, significantly improving the structural stability and component uniformity of the precursor. The directional coordination of zirconium atoms and polyol ligands not only achieves atomic-level uniform mixing of zirconium and carbon elements, but also fixes the active sites through a rigid skeleton, effectively inhibiting component segregation during high-temperature sintering. The hydrogen-bond-driven supramolecular cross-linked network gives the material excellent self-support and processability, while providing a continuous diffusion channel for the subsequent pyrolysis process, prompting the zirconium and carbon atoms to achieve short-range ordered arrangement during lattice reconstruction, which not only solves the problem of incomplete reaction caused by uneven contact of raw materials in traditional solid-phase methods, but also reduces the sintering activation energy through the chemical bonding mechanism, ultimately forming zirconium carbide ceramics with a high degree of densification and few grain boundary impurities.

[0006] In addition, the present invention provides a method for preparing bulk zirconium carbide ceramics, which uses the above-mentioned zirconium alkoxide supramolecular zirconium carbide ceramic precursor to assist sintering, comprising the following steps: A zirconium source material is dissolved in a carbon source material, and the temperature is kept to allow the material to fully react to form a viscous liquid of zirconium alkoxide supramolecules, wherein the carbon source material is a polyhydroxy organic compound; The viscous liquid of zirconium alkoxide supramolecules is mixed with zirconium carbide powder and sintered to form bulk zirconium carbide ceramics.

[0007] Furthermore, the zirconium source material is an inorganic salt containing zirconium.

[0008] Furthermore, the optional zirconium-containing inorganic salts include zirconium oxychloride and zirconium tetrachloride.

[0009] Furthermore, the polyhydroxy organic compound includes ethylene glycol, propylene glycol, glycerol or lactic acid.

[0010] Furthermore, the molar ratio of the zirconium source material to the carbon source material is 1:3 to 1:6. This molar ratio range achieves a dynamic balance in the precursor network structure by precisely controlling the chemical coordination environment of the zirconium and carbon active sites. A higher carbon source ratio ensures that the polyol ligands fully cover the zirconium atomic coordination sites, forming a continuous three-dimensional coordination network. At the same time, the excess hydroxyl groups strengthen the supramolecular crosslinking density through hydrogen bonds, giving the skeleton both structural flexibility and thermal stability. During the pyrolysis process, the excess carbon source not only acts as a reducing agent to inhibit the formation of zirconium oxide, but the activated carbon species produced by its gradient decomposition can also dynamically compensate for high-temperature carbon loss and maintain the zirconium-carbon stoichiometric balance. This ratio range can optimize the organic-inorganic interfacial energy, promote the coordinated migration of zirconium and carbon atoms at the molecular scale, and ultimately achieve effective repair of lattice defects and control of ceramic densification.

[0011] Furthermore, the zirconium source material was dissolved in the carbon source material and fully reacted at a temperature of 50-150°C for 48 hours. The hydrogen chloride gas produced by the reaction was absorbed by soda lime, and the reaction was naturally cooled to room temperature after completion. Through the coordinated optimization of gradient temperature control and reaction kinetics, the controlled growth of the molecular-level coordination network was achieved. The reaction window of 50-150°C not only met the activation energy requirements for organic-inorganic coordination bond formation, but also effectively suppressed the thermal decomposition of the polyol, ensuring the integrity of the supramolecular framework. The 48-hour holding period provided sufficient relaxation time for the multi-level hydrogen bond self-assembly, promoting the three-dimensional isotropic expansion of the zirconium alkoxide supramolecule. The hydrogen chloride released during the reaction was immediately neutralized by soda lime, eliminating the protonation interference of the acidic gas on the coordination bonds, maintaining the pH stability of the system, and avoiding the risk of equipment corrosion. The natural cooling strategy, through the thermal stress release mechanism, protected the supramolecular network from structural collapse during the phase transition, preserving the highly ordered zirconium-carbon prestructure for subsequent pyrolysis and sintering.

[0012] Furthermore, the zirconium alkoxide supramolecules were thoroughly mixed with zirconium carbide powder, with the mass ratio of zirconium carbide powder to zirconium source material ranging from 200:1 to 50:1. The zirconium carbide powder served as the matrix skeleton, providing a lattice template effect during sintering, guiding the epitaxial growth of the precursor decomposition products along pre-set crystal planes and effectively reducing the grain boundary energy barrier. The trace zirconium alkoxide supramolecules acted as a nanoscale binder phase. Their network structure produced highly active zirconium-carbon intermediates during pyrolysis, filling the interstitial spaces between the powders to enhance densification efficiency and strengthening the powder interface through chemical bonding. This gradient doping mechanism not only retained the intrinsic thermal stability of the zirconium carbide powder, but also utilized the in-situ nanophase generated by the precursor to eliminate the passivation layer on the powder surface, promoting the formation of sintering necks and grain fusion. The short-range ordered carbon network generated by the supramolecule decomposition inhibited abnormal grain growth, resulting in a uniform and fine-grained ceramic microstructure, thereby enhancing the material's mechanical strength and thermal shock resistance.

[0013] Furthermore, a zirconium carbide ceramic blank is formed by heat preservation at 40-100°C for 48 hours. The zirconium carbide ceramic blank is placed in an argon atmosphere and heat preserved at 1600-2200°C for 2 hours. After the reaction is completed, it is naturally cooled to room temperature to obtain a bulk zirconium carbide ceramic. The argon inert atmosphere effectively blocks the penetration of oxygen elements, preventing the oxidative decomposition of zirconium carbide at high temperatures and suppressing the gasification loss of free carbon, thereby maintaining the accuracy of the ceramic stoichiometric ratio. The plastic flow dominated by grain boundary diffusion promotes the rearrangement of powder particles and eliminates closed-pore defects. When the temperature continues to rise, the bulk diffusion mechanism is activated, driving the migration of atoms across the interface in the lattice, realizing grain boundary fusion and preferential grain growth. The heat preservation time balances the grain coarsening and densification processes, minimizing the grain boundary energy while avoiding abnormal grain growth. The natural cooling strategy promotes the orderly transformation of the metastable phase to the stable phase by slowly releasing the thermal stress gradient, while retaining the grain boundary structure characteristics of the high-temperature phase, ultimately obtaining a dense bulk ceramic with uniform grain size distribution, high grain boundary bonding strength and controllable residual stress.

[0014] The present invention can also provide a bulk zirconium carbide ceramic prepared by the above method.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: in the present invention, a zirconium alkoxide supramolecule is produced by reacting a polyhydroxy organic matter as a carbon source with a zirconium-containing salt as a zirconium source. This zirconium alkoxide supramolecule can be used as a zirconium carbide ceramic precursor to bond zirconium carbide ceramic powder and sinter to produce zirconium carbide ceramic with high density and good purity.

[0016] The precursor conversion method for producing zirconium carbide ceramics requires a high zirconium-to-carbon ratio to ensure their full conversion to zirconium carbide ceramics, as organic components readily volatilize at high reaction temperatures. However, a high zirconium-to-carbon ratio reduces raw material utilization, leading to lower yields. Traditional zirconium carbide ceramics are generally soluble only in hydrocarbon organic solvents and decompose upon contact with water, making them difficult to guarantee safety and environmental protection during actual use.

[0017] In the present invention, a zirconium alkoxide is produced by reacting a polyhydroxy organic compound as a carbon source with a zirconium-containing salt as a zirconium source. The zirconium atoms within the zirconium alkoxide are coordinated with the polyol ligands to form zirconium alkoxide molecules with a complex skeleton structure. The complex skeleton zirconium alkoxide molecules are then further cross-linked through hydrogen bonds between the hydroxyl groups to form a high-molecular network structure. This results in the zirconium alkoxide supramolecule having good viscosity and stability, and the carbon and zirconium atoms are fully and evenly mixed.

[0018] The green body composed of zirconium alkoxide supramolecules and zirconium carbide powder is subjected to a high-temperature sintering treatment at 1600-2200°C. During the process of generating the zirconium carbide ceramic, the complex network structure of the zirconium alkoxide supramolecules suppresses excessive volatilization loss of carbon atoms, thereby ensuring the required yield of the zirconium carbide ceramic from the zirconium alkoxide supramolecules and enabling successful sintering of the green body. Simultaneously, the carbon atoms and zirconium atoms in the zirconium alkoxide supramolecules are fully and evenly mixed, ensuring the uniformity and purity of the sintered zirconium carbide ceramic and preventing the generation of impurity phases in localized areas. Compared to traditional methods for preparing zirconium carbide ceramics, the present invention has a simple and easy process, does not require highly toxic organic solvents, and has a low overall process cost, safety, and environmental protection, meeting the requirements of green chemistry.

[0019] In actual use, a green body can be prepared by mixing zirconium alkoxide supramolecules with zirconium carbide ceramic powder. The green body is pressurelessly sintered at 1600°C to obtain a zirconium carbide ceramic block material with good uniformity, density and purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of a zirconium alkoxide supramolecular zirconium carbide ceramic precursor prepared by the present invention.

[0021] Figure 2 The present invention provides a hydrogen nuclear magnetic resonance spectrum result of a zirconium alkoxide supramolecular zirconium carbide ceramic precursor prepared in the present invention.

[0022] Figure 3 This is the result of the carbon nuclear magnetic resonance spectrum of a zirconium alkoxide supramolecular zirconium carbide ceramic precursor prepared by the present invention.

[0023] Figure 4 The present invention provides a zirconium carbide ceramic precursor prepared by mixing a zirconium alkoxide supramolecular zirconium carbide ceramic precursor with zirconium carbide ceramic powder and then sintering the mixture to prepare the zirconium carbide ceramic surface morphology SEM characterization results.

[0024] Figure 5 The XRD characterization results of the zirconium carbide ceramic phase prepared by sintering a zirconium alkoxide supramolecular zirconium carbide ceramic precursor prepared by the present invention and zirconium carbide ceramic powder. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] The present invention provides a zirconium alkoxide supramolecular zirconium carbide ceramic precursor. A zirconium alkoxide supramolecular structure is produced by reacting a polyhydroxy organic substance as a carbon source with a zirconium-containing salt as a zirconium source. The zirconium alkoxide supramolecular structure, as the zirconium carbide ceramic precursor, can be used to bond zirconium carbide ceramic powder and sinter to produce zirconium carbide ceramics with high density and good purity. The zirconium alkoxide supramolecular structure is synthesized by using a polyhydroxy organic substance as a carbon source and reacting with a zirconium-containing salt. The structure, as the zirconium carbide ceramic precursor, can effectively bond the zirconium carbide ceramic powder during the sintering process, ultimately forming a zirconium carbide ceramic product with high density and excellent purity.

[0027] The zirconium carbide ceramic preparation process based on the precursor conversion method requires an increase in the zirconium-to-carbon ratio in the system to achieve complete conversion, as organic components are easily volatile during high-temperature treatment. However, an excessively high zirconium-to-carbon ratio reduces the effective utilization of raw materials, leading to a decrease in overall yield. In addition, conventional zirconium carbide ceramic materials are only soluble in hydrocarbon organic solvents and undergo decomposition reactions when in contact with water, making it difficult to meet safety and environmental protection requirements in actual application scenarios.

[0028] The present invention will now be further described with reference to the embodiments and accompanying drawings: Example 1: 1) Take 0.01 mol of zirconium oxychloride, add 0.03 mol of propylene glycol, and mix thoroughly.

[0029] 2) The mixture was kept at 50°C for 48 hours. The generated hydrogen chloride gas was absorbed by soda lime. After the reaction was completed, it was naturally cooled to room temperature.

[0030] 3) The reaction product was thoroughly mixed with 0.5 mol of zirconium carbide powder and incubated at 60°C for 48 hours to form a zirconium carbide ceramic green body. The green body was then incubated at 1700°C for 2 hours under an argon atmosphere. After the reaction was complete, the green body was naturally cooled to room temperature to sinter and obtain a zirconium carbide ceramic block.

[0031] Example 2: 1) Take 0.01 mol of zirconium oxychloride, add 0.04 mol of propylene glycol, and mix thoroughly.

[0032] 2) The mixture was kept at 70°C for 48 hours. The generated hydrogen chloride gas was absorbed by soda lime. After the reaction was completed, it was naturally cooled to room temperature.

[0033] 3) The reaction product was thoroughly mixed with 1 mol of zirconium carbide powder and incubated at 50°C for 48 hours to form a zirconium carbide ceramic green body. The green body was then incubated at 1800°C for 2 hours under an argon atmosphere. After the reaction was complete, the green body was naturally cooled to room temperature to sinter and obtain a zirconium carbide ceramic block.

[0034] Example 3: 1) Take 0.01 mol of zirconium tetrachloride, add 0.04 mol of ethylene glycol, and mix thoroughly.

[0035] 2) The mixture was kept at 100°C for 48 hours. The generated hydrogen chloride gas was absorbed by soda lime. After the reaction was completed, it was naturally cooled to room temperature. The structural diagram of the product is shown in FIG. Figure 1 The H NMR spectrum of the product is shown as Figure 2 As shown, the results of the carbon NMR spectrum are as follows Figure 3 shown.

[0036] In the H NMR spectrum, the two triple split peaks a and b represent the α and β hydrogen atoms in the ethylene glycol monodentate ligand, respectively. Both are triple split due to coupling with the two hydrogen atoms in the same chemical environment on their adjacent carbon atoms. The broad peak c represents the alkyl hydrogen atoms in the ethylene glycol bidentate ligand. Due to the high-speed exchange coordination of the ligand, decoupling occurs, resulting in a broad peak morphology. The broad peak d on the right represents the hydroxyl hydrogen atom, which exhibits a broad peak morphology due to hydrogen bonding. In the C NMR spectrum, the three peaks a, b, and c represent the α carbon atom in the ethylene glycol monodentate ligand, the β carbon atom in the ethylene glycol monodentate ligand, and the alkyl carbon atom in the ethylene glycol bidentate ligand, respectively. The order of their chemical shifts is consistent with the order of their corresponding hydrogen atoms.

[0037] 3) The above reaction product was fully mixed with 1 mol of zirconium carbide powder and kept at 70°C for 48 hours to form a zirconium carbide ceramic blank. The blank was kept at 1600°C for 2 hours under an argon protection environment. After the reaction was completed, it was naturally cooled to room temperature to achieve sintering to obtain a zirconium carbide ceramic block. The surface morphology of the product was characterized by SEM. Figure 4 The XRD characterization results of the product phase are shown in Figure 5 As shown in the figure, the zirconium carbide ceramics produced by sintering are uniform, dense and pure.

[0038] Example 4: 1) Take 0.01 mol of zirconium oxychloride, add 0.03 mol of propylene glycol, and mix thoroughly.

[0039] 2) The mixture was kept at 70°C for 48 hours. The generated hydrogen chloride gas was absorbed by soda lime. After the reaction was completed, it was naturally cooled to room temperature.

[0040] 3) The reaction product was thoroughly mixed with 2 mol of zirconium carbide powder and heated at 100°C for 48 hours to form a zirconium carbide ceramic green body. The green body was then heated at 2200°C for 2 hours under an argon atmosphere. After the reaction was complete, the green body was naturally cooled to room temperature to sinter and obtain a zirconium carbide ceramic block.

[0041] Example 5: 1) Take 0.01 mol of zirconium tetrachloride, add 0.06 mol of lactic acid, and mix thoroughly.

[0042] 2) The mixture was kept at 70°C for 48 hours. The generated hydrogen chloride gas was absorbed by soda lime. After the reaction was completed, it was naturally cooled to room temperature.

[0043] 3) The reaction product was thoroughly mixed with 2 mol of zirconium carbide powder and incubated at 40°C for 48 hours to form a zirconium carbide ceramic green body. The green body was then incubated at 2000°C for 2 hours under an argon atmosphere. After the reaction was complete, the green body was naturally cooled to room temperature to sinter and obtain a zirconium carbide ceramic block.

[0044] Example 6: 1) Take 0.01 mol of zirconium oxychloride, add 0.04 mol of lactic acid, and mix thoroughly.

[0045] 2) The mixture was kept at 70°C for 48 hours. The generated hydrogen chloride gas was absorbed by soda lime. After the reaction was completed, it was naturally cooled to room temperature.

[0046] 3) The reaction product was thoroughly mixed with 1.5 mol of zirconium carbide powder and incubated at 80°C for 48 hours to form a zirconium carbide ceramic green body. The green body was then incubated at 2100°C under an argon atmosphere for 2 hours. After the reaction was complete, the green body was naturally cooled to room temperature to sinter and obtain a zirconium carbide ceramic block.

[0047] Example 7: 1) Take 0.01 mol of zirconium tetrachloride, add 0.06 mol of propylene glycol, and mix thoroughly.

[0048] 2) The mixture was kept at 70°C for 48 hours. The generated hydrogen chloride gas was absorbed by soda lime. After the reaction was completed, it was naturally cooled to room temperature.

[0049] 3) The reaction product was thoroughly mixed with 0.5 mol of zirconium carbide powder and incubated at 60°C for 48 hours to form a zirconium carbide ceramic green body. The green body was then incubated at 1900°C for 2 hours under an argon atmosphere. After the reaction was complete, the green body was naturally cooled to room temperature to sinter and obtain a zirconium carbide ceramic block.

[0050] Example 8: 1) Take 0.01 mol of zirconium tetrachloride, add 0.05 mol of propylene glycol, and mix thoroughly.

[0051] 2) The mixture was kept at 70°C for 48 hours. The generated hydrogen chloride gas was absorbed by soda lime. After the reaction was completed, it was naturally cooled to room temperature.

[0052] 3) The reaction product was thoroughly mixed with 1.5 mol of zirconium carbide powder and incubated at 70°C for 48 hours to form a zirconium carbide ceramic green body. The green body was then incubated at 1700°C for 2 hours under an argon atmosphere. After the reaction was complete, the green body was naturally cooled to room temperature to sinter and obtain a zirconium carbide ceramic block.

[0053] Example 9: 1) Take 0.01 mol of zirconium tetrachloride, add 0.06 mol of lactic acid, and mix thoroughly.

[0054] 2) The mixture was kept at 70°C for 48 hours. The generated hydrogen chloride gas was absorbed by soda lime. After the reaction was completed, it was naturally cooled to room temperature.

[0055] 3) The reaction product was thoroughly mixed with 1.8 mol of zirconium carbide powder and incubated at 40°C for 48 hours to form a zirconium carbide ceramic green body. The green body was then incubated at 2000°C under an argon atmosphere for 2 hours. After the reaction was complete, the green body was naturally cooled to room temperature to sinter and obtain a zirconium carbide ceramic block.

[0056] Example 10: 1) Take 0.01 mol of zirconium tetrachloride, add 0.06 mol of propylene glycol, and mix thoroughly.

[0057] 2) The mixture was kept at 70°C for 48 hours. The generated hydrogen chloride gas was absorbed by soda lime. After the reaction was completed, it was naturally cooled to room temperature.

[0058] 3) The reaction product was thoroughly mixed with 1.0 mol of zirconium carbide powder and incubated at 60°C for 48 hours to form a zirconium carbide ceramic green body. The green body was then incubated at 1900°C for 2 hours under an argon atmosphere. After the reaction was complete, the green body was naturally cooled to room temperature to sinter and obtain a zirconium carbide ceramic block.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A zirconium alkoxide supramolecular zirconium carbide ceramic precursor, characterized in that: It is produced by the reaction of polyhydroxy organic matter as a carbon source and zirconium-containing salts as a zirconium source. It has a network structure inside. The zirconium atoms and polyol ligands are combined through coordination bonds to form zirconium alkoxide molecules with a complex skeleton structure. The zirconium alkoxide molecules with a complex skeleton structure are further cross-linked through hydrogen bonds between hydroxyl groups to form a high molecular network structure.

2. A method for preparing bulk zirconium carbide ceramics, characterized in that: The zirconium alkoxide supramolecular zirconium carbide ceramic precursor according to claim 1 is used to assist sintering, comprising the following steps: A zirconium source material is dissolved in a carbon source material, and the temperature is kept to allow the material to fully react to form a viscous liquid of zirconium alkoxide supramolecules, wherein the carbon source material is a polyhydroxy organic compound; The viscous liquid of zirconium alkoxide supramolecules is mixed with zirconium carbide powder and sintered to form bulk zirconium carbide ceramics.

3. The method for preparing bulk zirconium carbide ceramics according to claim 2, characterized in that: The zirconium source material is an inorganic salt containing zirconium.

4. The method for preparing bulk zirconium carbide ceramics according to claim 2, wherein: Optional zirconium-containing inorganic salts include zirconium oxychloride and zirconium tetrachloride.

5. The method for preparing bulk zirconium carbide ceramics according to claim 2, characterized in that: Polyol organics include ethylene glycol, propylene glycol, glycerol or lactic acid.

6. The method for preparing bulk zirconium carbide ceramics according to claim 2, characterized in that: The molar ratio of the zirconium source material to the carbon source material is 1:3~1:

6.

7. The method for preparing bulk zirconium carbide ceramics according to claim 2, characterized in that: The zirconium source material is dissolved in the carbon source material and the reaction temperature is 50-150°C. The reaction is kept warm for 48 hours. The hydrogen chloride gas generated by the reaction is absorbed by soda lime. After the reaction is completed, it is naturally cooled to room temperature.

8. The method for preparing bulk zirconium carbide ceramics according to claim 2, characterized in that: The zirconium alkoxide supramolecules and zirconium carbide powder are fully mixed, and the mass ratio of the zirconium carbide powder to the zirconium source material is 200:1 to 50:

1.

9. The method for preparing bulk zirconium carbide ceramics according to claim 2, characterized in that: The zirconium carbide ceramic blank was formed by keeping the temperature at 40-100°C for 48 hours. The zirconium carbide ceramic blank was then kept at 1600-2200°C in an argon atmosphere for 2 hours and naturally cooled to room temperature after the reaction to obtain a bulk zirconium carbide ceramic.

10. A bulk zirconium carbide ceramic, characterized in that: The method is prepared by any one of claims 2 to 9.

Images