Ceramic material composition and preparation method thereof

Abstract

The invention relates to the technical field of ceramic material preparation, and discloses a ceramic material composition and a preparation method thereof. The composition comprises the following components in parts by weight: 85-97 parts of a main material, 1-8 parts of a rare earth oxide composite modifier, 0.5-10 parts of a core-shell structure pore-forming agent, 0.5-5 parts of a sintering aid and 0.3-2 parts of a self-curing forming agent. According to the invention, through the core-shell structure pore-forming agent, a core-shell form is constructed in the composition, so that the distribution uniformity and stability in the subsequent mixing and forming process are ensured, a porous ceramic structure with uniform pore distribution and consistent pore diameter can be accurately prepared, and the mechanical reliability of the material is improved; the formation of a non-covalent bond gel network can be triggered in the slurry, so that the mild self-curing forming of the high-solid-content slurry is realized, and the process replaces the dependence of traditional gel injection molding on a large number of organic monomers.

Description

Technical Field

[0001] This invention relates to the technical field of ceramic material preparation, and more specifically, to a ceramic material composition and its preparation method. Background Technology

[0002] Ceramic materials play an irreplaceable role in many high-tech fields such as machinery, electronics, chemical engineering, energy, and biomedicine due to their excellent hardness, wear resistance, high temperature resistance, corrosion resistance, and diverse electrical, magnetic, and optical physicochemical properties. Currently, in order to meet the increasingly stringent requirements of different application scenarios for ceramic material performance, composite modification and structural design of traditional ceramics have become the mainstream research direction. In terms of material systems, high-purity alumina, zirconium oxide, silicon nitride, and silicon carbide are used as structural ceramic matrices, and toughening and reinforcement are commonly achieved by introducing second-phase particles, whiskers, or fibers. In the field of functional ceramics, barium titanate and lead zirconate titanate are finely tuned by doping with rare earth or transition metal ions. Dielectric, piezoelectric, or ferroelectric properties are important considerations. Meanwhile, the preparation of porous ceramics has garnered significant attention in order to achieve lightweight, high specific surface area, or specific permeability. Conventional techniques primarily involve adding pore-forming agents, such as starch, polymer microspheres, or carbonates, to the ceramic preform. These agents decompose or volatilize during high-temperature sintering, leaving pores. In terms of manufacturing processes, traditional powder metallurgy remains the fundamental method for producing large quantities of relatively simple ceramic components. However, for products with complex shapes or extremely high requirements for microscopic uniformity, slurry-based processes such as injection molding, gel casting, or tape casting are more commonly used. These processes typically require the introduction of large amounts of organic binders, plasticizers, and dispersants to regulate rheological properties.

[0003] While existing technologies offer a rich selection of materials and processes, their technical approaches often involve trade-offs between performance, cost, and process complexity. Complex molding processes can introduce defects or lead to debinding difficulties. In terms of pore structure control, due to differences in density, particle size, and surface properties, pore-forming agent particles and ceramic powders are prone to agglomeration and uneven distribution during mixing and molding. This results in an excessively wide and randomly positioned pore size distribution within the final sintered body, becoming stress concentration points and severely impairing the material's mechanical reliability. Regarding material functionalization modification, additives such as rare earth oxides can effectively improve the sintering activity, grain boundary strength, and functional properties of ceramics, but their high cost necessitates efficient utilization. Simple physical mixing in existing technologies cannot ensure uniform dispersion of additives at the nanoscale or submicron level, easily leading to local agglomeration. This not only causes waste but may also become microcrack sources or cause abnormal grain growth due to excessively high local concentrations, thus degrading performance.

[0004] Therefore, developing a novel ceramic material composition and its supporting preparation method that can synergistically solve the problems of microstructure uniformity, efficient utilization of additives, and low-defect molding has significant technical and application value. Summary of the Invention

[0005] The purpose of this invention is to provide a ceramic material composition and its preparation method. By using a core-shell pore-forming agent, the core-shell morphology constructed within the composition ensures the uniformity and stability of the distribution during subsequent mixing and molding processes. This enables the precise preparation of porous ceramic structures with uniform pore distribution and consistent pore size, thereby improving the mechanical reliability of the material and aiming to solve the problems in the prior art.

[0006] The present invention is achieved as follows: a ceramic material composition comprising, by weight: 85-97 parts of main material, 1-8 parts of rare earth oxide composite modifier, 0.5-10 parts of core-shell structure pore-forming agent, 0.5-5 parts of sintering aid, and 0.3-2 parts of self-curing molding agent.

[0007] Furthermore, the main material is at least three of titanium nitride, aluminum oxide, zirconium oxide, aluminum nitride, and barium titanate, and the average particle size of the main material is 0.1-5 μm.

[0008] Furthermore, the rare earth oxide composite modifier is a mixture of at least two of yttrium oxide, cerium oxide, lanthanum oxide, and neodymium oxide, and the average particle size of the rare earth oxide composite modifier is not greater than 1 μm.

[0009] Furthermore, the core-shell pore-forming agent comprises a core made of polymethyl methacrylate, starch, or carbonate, and an organic binder shell made of polyvinyl alcohol, polyvinyl butyral, or polymethyl methacrylate that encapsulates the core.

[0010] Furthermore, in the core-shell pore-forming agent, the mass ratio of the core to the organic binder shell is 5-20:1, and the overall particle size of the core-shell pore-forming agent is 10-150 μm.

[0011] Furthermore, the sintering aid is one of silica, borate glass powder, and zirconium-containing calcium titanium minerals, and the average particle size of the sintering aid is 0.5-3 μm.

[0012] Furthermore, the zirconium-containing calcium titanium mineral is calcium zirconate, barium zirconate, or zinc zirconate, and the amount of the zirconium-containing calcium titanium mineral added is 0.2-2% of the total weight of the ceramic material composition.

[0013] Furthermore, the self-curing molding agent is an isobutylene copolymer ammonium salt, specifically an amine-modified isobutylene copolymer, which is used to prepare high-performance pressure-sensitive adhesives and adhesive sealants to bond low surface energy materials. The amount of the self-curing molding agent added is 0.3-0.5% of the total weight of the ceramic material composition.

[0014] Compared with the prior art, the ceramic material composition and its preparation method provided by the present invention have the following beneficial effects: 1. The core-shell structure pore-forming agent constructs a core-shell morphology within the composition, ensuring uniformity and stability of distribution during subsequent mixing and molding. This enables the precise preparation of porous ceramic structures with uniform pore distribution and consistent pore size, improving the mechanical reliability of the material. Secondly, the addition of 0.3-0.5% self-curing molding agent can trigger the formation of non-covalent gel networks in the slurry, achieving gentle self-curing molding of high-solids slurry. This process replaces the dependence of traditional gel casting on a large number of organic monomers, which not only simplifies the process but also significantly reduces the risk of internal stress and green body cracking during subsequent debinding, especially beneficial for near-net-shape forming of complex shapes or large-size ceramic parts. 2. By using rare earth oxide composite modifiers, based on optimized core-shell structure and uniform slurry, they can be fully dispersed in the ceramic matrix, effectively playing their role in refining grains, purifying grain boundaries, and improving high-temperature performance. This achieves efficient utilization of functional additives. The complete process chain, from core-shell preform synthesis and stepwise ball milling to air-assisted dehydration and low-stress degreasing, optimizes parameters at each step to suit the characteristics of rare earth oxide composite modifiers. This ensures consistency from microscopic pore structure and grain boundary state to macroscopic green body density, ultimately resulting in ceramic products that simultaneously optimize strength, toughness, thermal stability, and functional properties, thus broadening their application potential in high-end filtration, catalyst carriers, electronic devices, and other fields.

[0015] Mechanism of action The mechanism of action of core-shell pore-forming agents begins with molecular adsorption and interfacial isolation. Numerous -OH polar functional groups on the organic binder molecular chains are tightly adsorbed onto the surface of the core pore-forming agent particles through hydrogen bonds and van der Waals forces, forming a uniform molecular film shell. This shell physically isolates the core from the ceramic slurry at the molecular scale, preventing segregation caused by surface energy differences and providing a uniform stress transfer interface for subsequent removal. The self-curing molding agent, through its -COO groups on its molecular chains… - With NH4 + It plays a role in the extension of polymer chains in the slurry through electrostatic repulsion. When the slurry environment changes, NH4... +During migration, the electrostatic shielding between polymer chains weakens, and long-chain molecules rapidly intertwine through hydrogen bonds and van der Waals forces to form a three-dimensional gel network spanning ceramic particles. This network encapsulates and fixes all solid particles, including the core-shell pore-forming agent, at the molecular level, achieving macroscopic self-curing of the slurry. During the sintering process of rare earth oxides, the diffusion behavior of rare earth cations is selective due to the difference in ionic radius between them and the main material cations. They tend to accumulate at the boundaries of main material grains such as alumina or zirconium oxide, inhibiting abnormal grain growth by dragging and pinning the grain boundaries through solute. At the same time, rare earth ions can react with impurities at the grain boundaries to form a high-melting-point silicate liquid phase to strengthen the grain boundaries. The sintering aid generates a liquid phase at high temperatures or promotes material transport by forming a eutectic, thereby achieving densification at a lower temperature or in a shorter time. The process parameters for each step provide optimal kinetic conditions for molecular and atomic processes. The dissolution temperature of 60-85℃ in S11 allows the organic binder molecular chains to obtain sufficient kinetic energy to fully extend and achieve effective adsorption. The segmented ball milling speed and time in S12 and S13, through controllable mechanical energy input, achieve particle deagglomeration and surface hydroxylation without destroying the already formed core-shell structure or gel network precursor. The precise heating rate of 2-10℃ / min and the specific atmosphere in S15 precisely control the decomposition, pyrolysis and degreasing of organic matter, the diffusion rate of rare earth ions, and the nucleation and growth balance of the final grains, avoiding microstructural defects caused by thermal stress or excessively rapid reaction.

[0016] A method for preparing a ceramic material composition specifically includes the following steps: S11: Dissolve the organic binder in a solvent at 60-85℃ to form a fluid binder solution. Under stirring at 200-600 rpm, gradually add the powdered core pore-forming agent to the binder solution so that the binder uniformly coats the surface of the pore-forming agent particles. After drying at 40-80℃, a pore-forming agent preform with a core-shell structure is obtained. S12: Mix the main material, rare earth oxide composite modifier, sintering aid and the prepared core-shell structure pore-forming agent preform, add dispersant and solvent, and ball mill for 4-12 hours at a ball mill speed of 250-450 rpm to obtain a uniform slurry A. S13: Add a self-curing molding agent to slurry A, and continue ball milling for 0.5-2 hours at a ball mill speed of 100-300 rpm to obtain slurry B with self-curing properties; S14: After vacuum degassing of slurry B, inject it into the mold and allow it to undergo a self-curing gel reaction at 25-60℃. Let it stand for 1-6 hours to form a ceramic wet blank. S15: The ceramic wet blank is successively dried, dehydrated by air pressure, and degreased under low stress. Finally, it is sintered at high temperature to 1500-1800℃ in a protective atmosphere or vacuum environment at a heating rate of 2-10℃ / min and held for 2-10h to obtain a ceramic material composition.

[0017] Specifically, in S14, slurry B is defoamed under vacuum, including: Slurry B is placed in a vacuum environment, and the absolute pressure of the vacuum environment is maintained at 10-50 kPa; Under these vacuum conditions, the mixture is allowed to stand for 20-30 minutes, and then turned over after 5-10 minutes of standing to ensure that the outer surface of slurry B is in contact with the external phase, so as to remove air bubbles from the slurry. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] The implementation of the present invention will be described in detail below with reference to specific embodiments.

[0020] Example 1 A ceramic material composition, by weight, comprises: 85 parts of main material, 1 part of rare earth oxide composite modifier, 0.5 parts of core-shell structure pore-forming agent, 0.5 parts of sintering aid, and 0.3 parts of self-curing molding agent.

[0021] The main materials are titanium nitride, aluminum oxide, and zirconium oxide, mixed in a ratio of 1:2:1, and the average particle size of the main materials is 0.1 μm.

[0022] The rare earth oxide composite modifier is yttrium oxide and cerium oxide, mixed in a 1:1 ratio, and the average particle size of the rare earth oxide composite modifier is no greater than 1 μm.

[0023] The core-shell pore-forming agent comprises a core made of polymethyl methacrylate and an organic binder shell made of polyvinyl alcohol that encapsulates the core.

[0024] In the core-shell pore-forming agent, the mass ratio of the core to the organic binder shell is 5:1, and the overall particle size of the core-shell pore-forming agent is 10 μm.

[0025] The sintering aid is a mixture of silica, borate glass powder and zirconium-containing calcium titanium mineral, with a mixing ratio of 1:1:1 and an average particle size of 0.5 μm. The zirconium-containing calcium titanium mineral is calcium zirconate, and the amount of zirconium-containing calcium titanium mineral added is 0.2% of the total weight of the ceramic material composition.

[0026] The self-curing molding agent is an ammonium salt of isobutylene copolymer, wherein the isobutylene copolymer ammonium salt is an ammonium salt of isobutylene-maleic anhydride copolymer, the model is ISOBAM amide ammonium salt type, mainly produced by Kuraray Corporation of Japan, and is used as an adhesive component, protective colloid or ceramic adhesive. The amount of self-curing molding agent added is 0.3% of the total weight of the ceramic material composition.

[0027] A method for preparing a ceramic material composition specifically includes the following steps: S11: Dissolve the organic binder in a solvent at 60°C to form a fluid binder solution. Under stirring at 200 rpm, gradually add the powdered core pore-forming agent to the binder solution so that the binder uniformly coats the surface of the pore-forming agent particles. After drying at 40°C, a pore-forming agent preform with a core-shell structure is obtained. S12: Mix the main material, rare earth oxide composite modifier, sintering aid and the prepared core-shell structure pore-forming agent preform, add dispersant and solvent, and ball mill for 4 hours at a ball mill speed of 250 rpm to obtain a uniform slurry A. S13: Add a self-curing molding agent to slurry A, and continue ball milling for 0.5 h at a ball mill speed of 100 rpm to obtain slurry B with self-curing properties; S14: After vacuum degassing of slurry B, inject it into the mold, allow it to undergo a self-curing gel reaction at 25°C, and let it stand for 1 hour to form a ceramic wet blank. S15: The ceramic wet blank is successively dried, dehydrated by air pressure, and degreased under low stress. Finally, it is sintered at high temperature to 1500℃ in a protective atmosphere or vacuum environment at a heating rate of 2℃ / min and held at that temperature for 2 hours to obtain a ceramic material composition.

[0028] In S14, slurry B is defoamed under vacuum, including: Slurry B is placed in a vacuum environment, and the absolute pressure of the vacuum environment is maintained at 10 kPa. Under these vacuum conditions, the mixture is allowed to stand for 20 minutes, and then turned over after 5 minutes of standing to ensure that the outer surface of slurry B is in contact with the external phase, thereby removing air bubbles from the slurry.

[0029] Example 2 A ceramic material composition, by weight, comprises: 90 parts of main material, 5 parts of rare earth oxide composite modifier, 5 parts of core-shell structure pore-forming agent, 3 parts of sintering aid, and 1 part of self-curing molding agent.

[0030] The main materials are alumina, zirconium oxide, and aluminum nitride, mixed in a ratio of 1:1:1, and the average particle size of the main materials is 2μm.

[0031] The rare earth oxide composite modifier is composed of cerium oxide and lanthanum oxide in a mixing ratio of 1:2, and the average particle size of the rare earth oxide composite modifier is not greater than 1 μm.

[0032] The core-shell pore-forming agent comprises a core made of starch and an organic binder shell made of polyvinyl butyral that encapsulates the core.

[0033] In the core-shell pore-forming agent, the mass ratio of the core to the organic binder shell is 10:1, and the overall particle size of the core-shell pore-forming agent is 100μm.

[0034] The sintering aid is a mixture of silica, borate glass powder and zirconium-containing calcium titanium mineral, with a mixing ratio of 2:2:1 and an average particle size of 2μm. The zirconium-containing calcium titanium mineral is barium zirconate, and the amount of zirconium-containing calcium titanium mineral added is 1% of the total weight of the ceramic material composition.

[0035] The self-curing molding agent is an ammonium salt of isobutylene copolymer, wherein the isobutylene copolymer ammonium salt is an ammonium salt of isobutylene-maleic anhydride copolymer, the model is ISOBAM amide ammonium salt type, mainly produced by Kuraray Corporation of Japan, and is used as an adhesive component, protective colloid or ceramic adhesive. The amount of self-curing molding agent added is 0.4% of the total weight of the ceramic material composition.

[0036] A method for preparing a ceramic material composition specifically includes the following steps: S11: Dissolve the organic binder in a solvent at 75°C to form a fluid binder solution. Under stirring at 500 rpm, gradually add the powdered core pore-forming agent to the binder solution so that the binder uniformly coats the surface of the pore-forming agent particles. After drying at 60°C, a pore-forming agent preform with a core-shell structure is obtained. S12: Mix the main material, rare earth oxide composite modifier, sintering aid and the prepared core-shell structure pore-forming agent preform, add dispersant and solvent, and ball mill for 10 hours at a ball mill speed of 350 rpm to obtain a uniform slurry A. S13: Add a self-curing molding agent to slurry A, and continue ball milling for 1 hour at a ball mill speed of 200 rpm to obtain slurry B with self-curing properties; S14: After vacuum degassing of slurry B, it is injected into a mold and allowed to undergo a self-curing gel reaction at 45°C. After standing for 4 hours, a ceramic wet blank is formed. S15: The ceramic wet blank is successively dried, dehydrated by air pressure, and degreased under low stress. Finally, it is sintered at high temperature to 1700℃ in a protective atmosphere or vacuum environment at a heating rate of 8℃ / min and held at that temperature for 8 hours to obtain a ceramic material composition.

[0037] In S14, slurry B is defoamed under vacuum, including: Slurry B is placed in a vacuum environment, and the absolute pressure of the vacuum environment is maintained at 40 kPa; Under these vacuum conditions, the mixture is allowed to stand for 25 minutes, and then turned over after 5 minutes of standing to ensure that the outer surface of slurry B is in contact with the external phase, thereby removing air bubbles from the slurry.

[0038] Example 3 A ceramic material composition, by weight, comprises: 97 parts of main material, 8 parts of rare earth oxide composite modifier, 10 parts of core-shell structure pore-forming agent, 5 parts of sintering aid, and 2 parts of self-curing molding agent.

[0039] The main materials are zirconium oxide, aluminum nitride, and barium titanate, mixed in a ratio of 2:2:1, and the average particle size of the main materials is 5μm.

[0040] The rare earth oxide composite modifier is composed of lanthanum oxide and neodymium oxide in a 1:1 ratio, and the average particle size of the rare earth oxide composite modifier is no greater than 1 μm.

[0041] The core-shell pore-forming agent comprises a core made of carbonate and an organic binder shell made of polymethyl methacrylate that encapsulates the core.

[0042] In the core-shell pore-forming agent, the mass ratio of the core to the organic binder shell is 20:1, and the overall particle size of the core-shell pore-forming agent is 150μm.

[0043] The sintering aid is a mixture of silica, borate glass powder and zirconium-containing calcium titanium mineral, with a mixing ratio of 2:1:2 and an average particle size of 2μm. The zirconium-containing calcium titanium mineral is zinc zirconate, and the amount of zirconium-containing calcium titanium mineral added is 2% of the total weight of the ceramic material composition.

[0044] The self-curing molding agent is an ammonium salt of isobutylene copolymer, wherein the isobutylene copolymer ammonium salt is an ammonium salt of isobutylene-maleic anhydride copolymer, the model is ISOBAM amide ammonium salt type, mainly produced by Kuraray Corporation of Japan, and is used as an adhesive component, protective colloid or ceramic adhesive. The amount of self-curing molding agent added is 0.5% of the total weight of the ceramic material composition.

[0045] A method for preparing a ceramic material composition specifically includes the following steps: S11: Dissolve the organic binder in a solvent at 85°C to form a fluid binder solution. Under stirring at 600 rpm, gradually add the powdered core pore-forming agent to the binder solution so that the binder uniformly coats the surface of the pore-forming agent particles. After drying at 80°C, a pore-forming agent preform with a core-shell structure is obtained. S12: Mix the main material, rare earth oxide composite modifier, sintering aid and the prepared core-shell structure pore-forming agent preform, add dispersant and solvent, and ball mill for 12 hours at a ball mill speed of 450 rpm to obtain a uniform slurry A. S13: Add a self-curing molding agent to slurry A, and continue ball milling for 2 hours at a ball mill speed of 300 rpm to obtain slurry B with self-curing properties; S14: After vacuum degassing of slurry B, inject it into the mold, allow it to undergo a self-curing gel reaction at 60°C, and let it stand for 6 hours to form a ceramic wet blank. S15: The ceramic wet blank is successively dried, dehydrated by air pressure, and degreased under low stress. Finally, it is sintered at high temperature to 1800℃ at a heating rate of 10℃ / min under a protective atmosphere or vacuum environment, and held at that temperature for 10h to obtain a ceramic material composition.

[0046] In S14, slurry B is defoamed under vacuum, including: Slurry B is placed in a vacuum environment, and the absolute pressure of the vacuum environment is maintained at 50 kPa. Under these vacuum conditions, the mixture is allowed to stand for 30 minutes, and then turned over after 10 minutes of standing to ensure that the outer surface of slurry B is in contact with the external phase, thereby removing air bubbles from the slurry.

[0047] Comparison Example The key test data of the ceramic materials prepared according to Examples 1-3 above are compared with those of the ceramic materials in the control examples (prior art). The specific test data are as follows: Table 1: Processing methods of ceramic materials in comparison Table 2: Comparison of Key Test Data for Ceramic Materials Specifically, the methods for obtaining the test parameters for the above-mentioned projects are as follows: Formula differences can be directly defined and compared by accurately weighing and recording the type, specifications (such as purity and particle size), and weight or percentage of each component.

[0048] Key process characteristics are achieved by directly recording and controlling critical parameters such as temperature, time, pressure, speed, and atmosphere at each step through instruments or programs in equipment (such as ball mills and sintering furnaces).

[0049] Bending strength is determined by machining ceramic samples to standard dimensions, applying a constant rate of load to a three-point or four-point bending tester until fracture, and then calculating the strength using a formula.

[0050] Porosity is typically determined according to GB / T 1966 or ASTM C20 using the Archimedes displacement method: the dry weight, suspended weight after impregnation and saturation of the sample are measured, and the open porosity is calculated using a formula.

[0051] The average pore size (μm) is determined according to GB / T 21650.1 by measuring the pressure required to force mercury into the pores under external pressure, calculating the corresponding pore size and volume, and thus obtaining the average pore size and pore size distribution curve.

[0052] Comparative analysis of the data in Tables 1-2 shows that the three embodiments of this technical solution are significantly superior to the control example in terms of strength and pore size uniformity. This directly proves that the core-shell structure pore-forming agent effectively solves the problem of large pore size dispersion and stress weaknesses caused by uneven distribution in traditional pore-forming agents (control example). At the same time, the application of the self-curing molding agent reduces defects in the green body, laying the foundation for the preparation of high-strength green bodies. This is a direct effect of the formulation system innovation. Precision process chains have a clear performance enhancement effect: After adopting optimized processes such as "pneumatic dehydration" and "low-stress degreasing", Examples 1 and 2 have better strength, uniformity and thermal shock stability than Example 3 with conventional processes. This shows that customized process chains (S1-S5) that match the innovative formulation can further release the material potential and reduce process defects, verifying the necessity of method innovation.

[0053] While maintaining high porosity (45-50%), the embodiment achieved a strength far exceeding that of the control example. This breaks through the bottleneck of the traditional porous ceramics where "strength and porosity are mutually exclusive." The core lies in achieving a uniform and controllable distribution of pores through a core-shell structure, avoiding the fatal weakening of strength caused by random large pores.

[0054] Table 3: Comparison of Process Parameters and Microstructure Parameters Table 4: Test methods for process parameters and microstructure parameters Table 5 provides a detailed description of the organic adhesive shell, which consists of polyvinyl alcohol, polyvinyl butyral, or polymethyl methacrylate and encapsulates the core. Table 5 Based on the process parameters and microstructure parameters in Table 3-4, and conventional machine testing methods, this technical solution can be summarized into the following four aspects: 1. Precise design and control of pore structure. Data shows that the pore size distribution variation coefficient of the embodiment is much lower than that of the control example, and the pore sphericity is high. This directly confirms that the core-shell structure pore-forming agent achieves uniform dispersion and controlled decomposition in the green body through pre-coating, forming pores with uniform pore size and regular morphology. This is the reason why its bending strength is significantly higher than that of the control example under the same porosity.

[0055] 2. The mild molding technology for low-defect green bodies demonstrates that the examples have controllable gel time and extremely high green body strength, while the degreasing cracking rate is extremely low. This is due to the self-curing molding agent forming a uniform gel network through physical cross-linking, which replaces the chemical polymerization or large amount of adhesives in traditional processes, thereby achieving near-net-shape and low internal stress molding, laying the foundation for obtaining defect-free products through subsequent sintering.

[0056] 3. Grain boundary engineering and efficient sintering: Data shows that the average grain size of the embodiments is smaller and the grain boundary phase is thinner and more uniform. This is attributed to the synergistic effect of rare earth oxide composite modifier and special sintering aid. Rare earth ions effectively pin the grain boundaries and inhibit abnormal grain growth, while the sintering aid promotes low-temperature densification, thereby achieving fine grain strengthening and grain boundary purification of the microstructure and significantly improving the thermal shock stability of the material.

[0057] 4. The entire process is coordinated and stable. Data proves that the slurry settling stability of the embodiment is excellent, the sintering temperature is reduced and the product size accuracy is high. The precise control of parameters in each step ensures the uniformity and stability of the components from mixing to molding.

[0058] As shown in Table 5, the experimental data of this technical solution, through the core-shell structure pore-forming agent, constructs a core-shell morphology within the composition, ensuring the uniformity and stability of the distribution during subsequent mixing and molding. This enables the precise preparation of porous ceramic structures with uniform pore distribution and consistent pore size, improving the mechanical reliability of the material. Based on the optimized core-shell structure and uniform slurry, the rare earth oxide composite modifier can be fully dispersed in the ceramic matrix, effectively playing its role in refining grains, purifying grain boundaries, and improving high-temperature performance. This achieves efficient utilization of functional additives. The complete process chain, from core-shell preform synthesis and stepwise ball milling to air-assisted dehydration and low-stress degreasing, optimizes parameters for each step based on the characteristics of the rare earth oxide composite modifier, ensuring consistency from microscopic pore structure and grain boundary state to macroscopic green body density.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A ceramic material composition, characterized in that, By weight, it includes: 85-97 parts of main material, 1-8 parts of rare earth oxide composite modifier, 0.5-10 parts of core-shell structure pore-forming agent, 0.5-5 parts of sintering aid, and 0.3-2 parts of self-curing molding agent.

2. The ceramic material composition as described in claim 1, characterized in that, The main material is at least three of titanium nitride, aluminum oxide, zirconium oxide, aluminum nitride and barium titanate, and the average particle size of the main material is 0.1-5 μm.

3. The ceramic material composition as described in claim 2, characterized in that, The rare earth oxide composite modifier is a mixture of at least two of yttrium oxide, cerium oxide, lanthanum oxide and neodymium oxide, and the average particle size of the rare earth oxide composite modifier is not greater than 1 μm.

4. The ceramic material composition as described in claim 3, characterized in that, The core-shell pore-forming agent comprises a core made of polymethyl methacrylate, starch, or carbonate, and an organic binder shell made of polyvinyl alcohol, polyvinyl butyral, or polymethyl methacrylate that encapsulates the core.

5. The ceramic material composition as described in claim 4, characterized in that, In the core-shell pore-forming agent, the mass ratio of the core to the organic binder shell is 5-20:1, and the overall particle size of the core-shell pore-forming agent is 10-150 μm.

6. The ceramic material composition as described in claim 5, characterized in that, The sintering aid is a mixture of silica, borate glass powder and zirconium-containing calcium titanium minerals, and the average particle size of the sintering aid is 0.5-3 μm.

7. The ceramic material composition according to claim 6, characterized in that, The zirconium-containing calcium titanium mineral is calcium zirconate, barium zirconate, or zinc zirconate, and the amount of the zirconium-containing calcium titanium mineral added is 0.2-2% of the total weight of the ceramic material composition.

8. The ceramic material composition as described in claim 7, characterized in that, The self-curing molding agent is an isobutylene copolymer ammonium salt, and the amount of the self-curing molding agent added is 0.3-0.5% of the total weight of the ceramic material composition.

9. A method for preparing a ceramic material composition according to any one of claims 1-8, characterized in that, Specifically, the following steps are included: S11: Dissolve the organic binder in a solvent at 60-85℃ to form a fluid binder solution. Under stirring at 200-600 rpm, gradually add the powdered core pore-forming agent to the binder solution so that the binder uniformly coats the surface of the pore-forming agent particles. After drying at 40-80℃, a pore-forming agent preform with a core-shell structure is obtained. S12: Mix the main material, rare earth oxide composite modifier, sintering aid and the prepared core-shell structure pore-forming agent preform, add dispersant and solvent, and ball mill for 4-12 hours at a ball mill speed of 250-450 rpm to obtain a uniform slurry A. S13: Add a self-curing molding agent to slurry A, and continue ball milling for 0.5-2 hours at a ball mill speed of 100-300 rpm to obtain slurry B with self-curing properties; S14: After vacuum degassing of slurry B, inject it into the mold and allow it to undergo a self-curing gel reaction at 25-60℃. Let it stand for 1-6 hours to form a ceramic wet blank. S15: The ceramic wet blank is successively dried, dehydrated by air pressure, and degreased under low stress. Finally, it is sintered at high temperature to 1500-1800℃ in a protective atmosphere or vacuum environment at a heating rate of 2-10℃ / min and held for 2-10h to obtain a ceramic material composition.

10. The method for preparing a ceramic material composition as described in claim 9, characterized in that, In S14, slurry B is defoamed under vacuum, including: Slurry B is placed in a vacuum environment, and the absolute pressure of the vacuum environment is maintained at 10-50 kPa; Under these vacuum conditions, the mixture is allowed to stand for 20-30 minutes, and then turned over after 5-10 minutes of standing to ensure that the outer surface of slurry B is in contact with the external phase, so as to remove air bubbles from the slurry.

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