High porosity high strength ultrathin wall cordierite honeycomb ceramic and preparation method

Abstract

This invention relates to the field of honeycomb ceramic technology, specifically to a high-porosity, high-strength, ultrathin-walled cordierite honeycomb ceramic and its preparation method. In its main component, the talc with a narrow, lamellar particle size distribution has an Fe2O3 mass percentage ≥1.5%, an aspect ratio ≥10, and a particle size D... 97 The particle size is ≤30μm; the sphericity of both spherical alumina and molten spherical silica is ≥98%, and the mass percentage of the amorphous phase in molten spherical silica is ≥99.5%; the pore-forming agent is ultrafine silicon carbide powder. By limiting the morphology and particle size, the raw materials have excellent flowability and packing characteristics, effectively solving the technical problems of difficult molding and low green strength of high-pore-density ultrathin-walled honeycomb ceramic carriers; ultrafine silicon carbide powder replaces traditional organic pore-forming agents, and can decompose and volatilize during the low-temperature firing stage, significantly reducing the risk of firing cracking, improving the product qualification rate, and avoiding the problem of large-diameter defects caused by organic pore-forming agents.

Description

Technical Field

[0001] This invention relates to the field of honeycomb ceramic technology, and more specifically, to a high-porosity, high-strength, ultrathin-walled cordierite honeycomb ceramic and its preparation method. Background Technology

[0002] With the implementation of Euro 7 and China VII emission regulations, emission limits for pollutants have become increasingly stringent. Cold start emissions from motor vehicles account for approximately 70% of total emissions. Therefore, to meet emission standards, it is necessary to improve the conversion efficiency of catalysts during cold starts. This improvement in cold start conversion efficiency places demands on the honeycomb ceramic carrier, requiring it to have a low heat capacity and high efficiency.

[0003] The technical measures to reduce the heat capacity of the carrier are to increase the carrier porosity, reduce the material density, and simultaneously reduce the carrier wall thickness to an ultra-thin wall of 1-2 mil. However, as the carrier porosity increases and the wall thickness decreases, the carrier strength decreases. Subsequent catalyst coating using robotic arms is prone to damage, and subsequent encapsulation is also prone to damage. Therefore, in the future, in addition to high porosity and ultra-thin walls, carriers also need to maintain high strength.

[0004] With the increase in porosity and the thinning of wall thickness, the conventional preparation method uses flaky talc, flaky kaolin, and irregularly shaped alumina as the main raw materials, and adds a large amount of binder, dispersant, and lubricant to improve the fluidity of the mud; and adds a large amount of organic pore-forming agent to increase porosity. This method brings many problems.

[0005] First, as the pore density increases and the wall thickness decreases, the requirements for the fluidity of the clay material increase. Flake-shaped and irregularly shaped raw materials are prone to bridging when forming and extruding high-pore-density ultra-thin-walled products, resulting in high extrusion pressure (reaching more than 20MPa) and many product defects.

[0006] In addition, the addition of a large amount of binders, dispersants, lubricants and organic pore-forming agents causes the organic additives to decompose rapidly during sintering, generating a large amount of heat. This creates a temperature difference between the inside and outside of the honeycomb ceramic carrier, generating thermal stress. Furthermore, the ultra-thin wall thickness weakens the strength of the green body, causing cracking during firing. At the same time, the micropores formed by the use of organic pore-forming agents have large pore sizes, generally reaching 3-20μm. Large micropore sizes are detrimental to the strength of the carrier. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a high-porosity, high-strength, ultrathin-walled cordierite honeycomb ceramic and its preparation method.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: This invention provides a high-porosity, high-strength, ultra-thin-walled cordierite honeycomb ceramic, the main components of which include flaky narrow-particle-size talc, spherical alumina, molten spherical silica, and a pore-forming agent; In the flaky, narrow-particle-size talc, the mass percentage of Fe2O3 is greater than or equal to 1.5%, the aspect ratio is greater than or equal to 10, and the particle size D is... 97 Less than or equal to 30 μm; The sphericity of both the spherical alumina and the molten spherical silica is greater than or equal to 98%, and the mass percentage of the amorphous phase in the molten spherical silica is greater than or equal to 99.5%. The pore-forming agent is ultrafine silicon carbide powder.

[0009] Based on the above technical solution, the present invention can be further improved as follows.

[0010] Furthermore, in the flaky, narrow-particle-size talc, the mass percentage of silicon dioxide is greater than or equal to 57.0%, the mass percentage of magnesium oxide is greater than or equal to 29.0%, the mass percentage of calcium oxide is less than or equal to 0.2%, and the particle size D... 50 The particle size is 11-17 μm, D. 97 Less than or equal to 25μm.

[0011] Furthermore, the particle size D of the spherical alumina 50 The particle size is 0.4-5.0 μm, with a particle size D. 97 The alumina is less than or equal to 10 μm and has a mass percentage of 99.50%.

[0012] Furthermore, the particle size D of the molten spherical silica 50 The particle size is 11-17 μm, D. 97 Less than or equal to 25μm.

[0013] Furthermore, the particle size D of the ultrafine silicon carbide powder 50 The particle size is 0.4-4.0 μm, and the particle size D is... 97 The size is less than or equal to 15 μm, the mass percentage of calcium oxide is less than or equal to 0.2%, and the total mass percentage of potassium oxide and sodium oxide is less than 0.5%.

[0014] Furthermore, in the main components, the mass percentage of flaky narrow-particle-size talc is 41.80%-46.06%, the mass percentage of spherical alumina is 34.60%-36.04%, the mass percentage of molten spherical silica is 5.83%-18.58%, and the mass percentage of ultrafine silicon carbide powder is 5%-13%.

[0015] Furthermore, the honeycomb ceramic also includes a binder, which is low-viscosity ammonium lignosulfonate with a viscosity of 100-1000 mPa·s in a 2% aqueous solution at 20°C.

[0016] Furthermore, the honeycomb ceramic also includes a lubricant, which is a nano-sized paraffin emulsion with a particle size of 5-10 nm and a solid content of 60-80% by mass.

[0017] The present invention also provides a method for preparing high-porosity, high-strength, ultra-thin-walled cordierite honeycomb ceramics as described above, wherein the main components are used to prepare clay segments, and the clay segments are then extruded, microwave-dried, and fired to obtain the honeycomb ceramics.

[0018] Furthermore, the extrusion pressure is 4-8 MPa, the firing temperature is 1400-1450℃, and the holding time during firing is 10-20 hours.

[0019] The beneficial effects of this invention are as follows: (1) The high porosity, high strength, ultrathin wall cordierite honeycomb ceramic of the present invention uses a raw material system of flaky narrow-particle-size high iron-content talc, high sphericity spherical alumina, molten spherical silica and ultrafine silicon carbide micro powder as pore-forming agents, so that the powder has excellent flowability and packing characteristics, effectively solving the technical problems of difficult molding and low green strength of high pore density (400-1200cpsi) ultrathin wall (1-3mil) honeycomb ceramic carrier; (2) The high porosity, high strength, ultrathin wall cordierite honeycomb ceramic of the present invention uses ultrafine silicon carbide micro powder as an inorganic pore-forming agent to replace the traditional organic pore-forming agent. Its decomposition temperature is low and it can decompose and volatilize in the low temperature firing stage, which reduces heat accumulation and internal and external temperature difference, significantly reduces the risk of firing cracking, improves the product qualification rate, and avoids the problem of large pore diameter (3-20μm) defects generated by organic pore-forming agents. (3) The high porosity, high strength, ultrathin wall cordierite honeycomb ceramic of the present invention uses high-purity spherical raw materials and narrow-particle-size flaky talc, which promotes the synthesis reaction of cordierite at relatively low temperatures, forming a well-developed crystal structure, effectively reducing the coefficient of thermal expansion, and having excellent thermal shock resistance. (4) The high porosity, high strength, ultrathin wall cordierite honeycomb ceramic of the present invention achieves high porosity while maintaining good compressive strength through the synergistic optimization of raw material morphology and particle size, overcoming the contradiction of the sharp decline in strength of traditional high porosity ceramics, and achieving an excellent balance between high porosity and high strength. (5) The method for preparing high porosity, high strength, ultrathin wall cordierite honeycomb ceramics of the present invention has a simple production process and low cost, and is suitable for preparing carriers that meet various needs. Attached Figure Description

[0020] Figure 1 SEM images of the ultrafine silicon carbide powder used in Examples 1-3 of this invention; Figure 2 These are SEM images of the molten spherical alumina raw materials used in Examples 1-3 of this invention; Figure 3 This is a SEM image of the product of Embodiment 7 of the present invention. Detailed Implementation

[0021] The principles and features of the present invention are described below. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0022] The high-porosity, high-strength, ultrathin-walled cordierite honeycomb ceramic of the present invention comprises, as its main components, lamellar narrow-particle-size talc, spherical alumina, fused spherical silica, and a pore-forming agent; in the lamellar narrow-particle-size talc, the mass percentage of Fe2O3 is greater than or equal to 1.5%, the aspect ratio is greater than or equal to 10, and the particle size D is... 97 The particle size is less than or equal to 30 μm; the sphericity of both spherical alumina and molten spherical silica is greater than or equal to 98%, and the mass percentage of the amorphous phase in molten spherical silica is greater than or equal to 99.5%; the pore-forming agent is ultrafine silicon carbide powder.

[0023] The high-porosity, high-strength, ultrathin-walled cordierite honeycomb ceramic of the present invention achieves significant effects through the limitation of each component, as detailed below: Talc with a narrow, flaky particle size distribution and a large aspect ratio is used for particle size control. 97 With a particle size of ≤30μm, the raw materials can react at low temperatures, effectively reducing the firing temperature and heat accumulation, thereby significantly reducing the risk of firing cracks and improving the product qualification rate. At the same time, the talc has a high iron content, which makes it easy to form a liquid phase, promoting the synthesis reaction of cordierite, helping to form a more perfect crystal structure, and improving the thermal stability of the material.

[0024] Both spherical alumina and fused spherical silica possess high sphericity, significantly improving powder flowability. This allows for controlled extrusion pressure even at pore densities as high as 1200 cpsi when preparing ultrathin-walled (1-3 mil) honeycomb ceramics, overcoming the technical bottleneck of difficult high-porosity ultrathin-walled carrier molding. Simultaneously, it avoids the problem of large-pore-size (3-20 μm) defects caused by the decomposition of organic pore-forming agents, effectively controlling the median pore size within a fine range of 1.0-6.0 μm. The high sphericity of spherical alumina prevents the residue of corundum phases with high thermal expansion coefficients, which are often caused by the difficulty in achieving 100% conversion of alumina to cordierite.

[0025] Ultrafine silicon carbide powder, as an inorganic pore-forming agent, has a low decomposition temperature and can decompose and volatilize at low temperatures, further reducing heat accumulation and firing cracking. The introduction of ultrafine silicon carbide particles refines the pore size distribution, and combined with the uniform packing structure formed by the high sphericity raw materials, enables honeycomb ceramics to maintain excellent compressive strength under ultra-high porosity conditions, achieving a good balance between high porosity and high strength.

[0026] Furthermore, the high content of amorphous phase in the molten spherical silica ensures reactivity, promotes the low-temperature synthesis of cordierite, and keeps the coefficient of thermal expansion at an extremely low level, significantly improving the product's thermal shock resistance. If the content of amorphous phase is too low, the content of cristobalite phase will be too high. If the cristobalite phase is not completely converted into cordierite phase and leaves residues, its coefficient of thermal expansion will be very large, resulting in a large coefficient of thermal expansion of the carrier, poor thermal shock resistance, and easy cracking during use.

[0027] Preferably, in the flaky, narrow-particle-size talc, the mass percentage of silicon dioxide is greater than or equal to 57.0%, the mass percentage of magnesium oxide is greater than or equal to 29.0%, the mass percentage of calcium oxide is less than or equal to 0.2%, and the particle size D... 50 The particle size is 11-17 μm, D. 97 Less than or equal to 25μm.

[0028] The aforementioned flaky, narrow-particle-size talc is designed with a high silica and high magnesium oxide chemical composition, making the chemical composition of the talc raw material closer to the theoretical composition ratio of cordierite (2MgO·2Al2O3·5SiO2). This reduces side reactions during firing, improving the purity and crystal integrity of the cordierite phase. Strict control of calcium oxide content effectively inhibits the formation of low-melting-point glassy phases or anorthite and other impurities at high temperatures, preventing damage to the cordierite crystal structure and ensuring a lower coefficient of thermal expansion and superior thermal shock stability. The specific particle size design ensures highly uniform talc particle composition, allowing for regular and orderly directional arrangement during molding, forming a dense and uniform green body structure. This significantly improves the green body strength of ultra-thin-walled honeycomb ceramics and reduces deformation and cracking defects during drying and firing.

[0029] Preferably, the particle size D of spherical alumina 50 The particle size is 0.4-5.0 μm, with a particle size D. 97 The alumina has a particle size of less than or equal to 10 μm and a mass percentage of greater than or equal to 99.50%. High-purity alumina avoids the formation of glassy or heterocrystalline phases by impurities such as sodium, potassium, and calcium at high temperatures, ensuring the purity and crystal integrity of the cordierite main crystalline phase in honeycomb ceramics, thereby giving the material an extremely low coefficient of thermal expansion and excellent thermal shock stability.

[0030] Preferably, the particle size D of the molten spherical silica is... 50 The particle size is 11-17 μm, D. 97 The particle size is less than or equal to 25 μm; the above particle size limit matches the particle size range of flaky narrow-size talc, enabling effective synergistic effects among the components.

[0031] Preferably, both spherical alumina and molten spherical silica can be prepared by flame method or flame spheroidization method to ensure their sphericity.

[0032] Preferably, the particle size D of the ultrafine silicon carbide powder is... 50 The particle size is 0.4-4.0 μm, and the particle size D is... 97 The particle size is less than or equal to 15 μm, the mass percentage of calcium oxide is less than or equal to 0.2%, and the total mass percentage of potassium oxide and sodium oxide is less than 0.5%. This ultrafine silicon carbide powder can prevent the reduction of carrier strength caused by the formation of large median-sized micropores. At the same time, the content of calcium oxide is limited, as excessive content will affect the thermal expansion coefficient of the carrier.

[0033] For ultrafine silicon carbide powder, there are no particular limitations on the content of free silicon and residual carbon. A small amount of free silicon forms silica sol through hydration during the preparation of clay, which can improve the strength of the green body and facilitate firing; residual carbon is converted into carbon dioxide during firing, which helps to increase porosity.

[0034] Further preferred, the ultrafine silicon carbide powder is refractory-grade silicon carbide dust removal powder, which has the advantage of low cost.

[0035] In the main components of the honeycomb ceramic of the present invention, the mass percentage of flaky narrow-particle-size talc is 41.80%-46.06%, the mass percentage of spherical alumina is 34.60%-36.04%, the mass percentage of molten spherical silica is 5.83%-18.58%, and the mass percentage of ultrafine silicon carbide powder is 5%-13%.

[0036] The above-mentioned component ratio promotes the synthesis and development of high-purity cordierite crystals, ensuring that the material has an extremely low coefficient of thermal expansion and excellent thermal shock stability. It can precisely adjust the porosity and pore size distribution of the product to meet the product requirements of different pore densities and wall thicknesses. With the addition of a small amount of ultrafine silicon carbide powder, a high porosity of 50%-68% can be achieved. At the same time, it avoids the problem of large pore size (3-20μm) defects caused by the decomposition of organic pore-forming agents, and finely controls the median pore size within the range of 1.0-6.0μm. In addition, the decomposition and volatilization of silicon carbide at low temperature reduces heat accumulation, significantly reduces the risk of firing cracking, and improves the product qualification rate.

[0037] Preferably, the honeycomb ceramic also includes a binder, which is a low-viscosity ammonium lignosulfonate binder with a viscosity of 100-1000 mPa·s in a 2% aqueous solution at 20°C. The advantages of this binder are its low viscosity, easy reaction of cellulose with water, good film-forming properties, which helps improve the plasticity and flowability of the clay. Furthermore, ammonium lignosulfonate does not burn and decomposes rapidly during sintering, and has a wide carbonization temperature range, which is beneficial for firing.

[0038] Preferably, the low-viscosity ammonium lignosulfonate binder is ammonium lignosulfonate carboxymethyl cellulose ammonium.

[0039] Preferably, the honeycomb ceramic also includes a lubricant, which is a nano-sized paraffin emulsion. The particle size of the nano-sized paraffin emulsion is 5-10 nm, and the solid content by mass percentage is 60-80%. In this nano-sized paraffin emulsion, the paraffin particles are at the nanoscale, which can fill the spaces between the raw material particles, play a lubricating role, improve the fluidity of the clay, and reduce the extrusion pressure. At the same time, the paraffin has a low melting and volatilization temperature, and it is easy to decompose and volatilize at low temperatures, reducing heat accumulation and reducing firing cracks.

[0040] The present invention relates to a high-porosity, high-strength, ultra-thin-walled cordierite honeycomb ceramic with a pore density of 400-1200 cpsi and a wall thickness of 1-3 mil. Simultaneously, it exhibits an extremely low coefficient of thermal expansion, ranging from 0.08 to 0.34 × 10⁻⁶. -6 / ℃, A-axis compressive strength ≥3.5MPa, and thermal shock resistance temperature up to 750-1000℃. This honeycomb ceramic meets the stringent requirements of future China VII and Euro VII regulations for low heat capacity and high efficiency exhaust gas purification carriers.

[0041] Preferably, there are no particular restrictions on the shape of the honeycomb grid in the honeycomb structure. A single hole shape such as triangle, square, or hexagon can be used, or multiple hole shapes such as square, hexagon, or asymmetrical shape can be used. It is not necessary to use a single hole shape in the honeycomb structure. For example, a square hole is preferred.

[0042] Preferably, the specific dimensions of the honeycomb ceramic can be 2-13 inches in diameter and 2-12 inches in height.

[0043] The present invention discloses a method for preparing high-porosity, high-strength, ultra-thin-walled cordierite honeycomb ceramics, which involves preparing clay segments using main components, and then extruding, microwave drying, and firing the clay segments to obtain honeycomb ceramics.

[0044] Preferably, the extrusion pressure is 4-8 MPa, the firing temperature is 1400-1450℃, and the holding time during firing is 10-20 hours.

[0045] In the above preparation process, the flaky, narrow-particle-size talc with high iron content of the present invention forms a liquid phase above 950°C. The temperature range in which the maximum amount of liquid phase is generated during the synthesis of cordierite is 1300-1400°C. Under an oxidizing atmosphere, silicon carbide begins to be slightly oxidized at 1100-1200°C, forming silicon dioxide and releasing carbon dioxide. At 1300-1400°C, it is completely oxidized to silicon dioxide and carbon dioxide, releasing a large amount of carbon dioxide gas. Due to the high viscosity of the cordierite liquid phase, the gas is not easily discharged, forming a large number of closed pores. Therefore, closed pores with high porosity (50-68%) and small median pore size (1-6μm) are obtained. The small pore size of the closed pores reduces the material density while allowing the material to maintain relatively high strength. The silica formed by the oxidation of silicon carbide can also provide the silica component required for the synthesis of cordierite, reducing the amount of molten spherical silica added and lowering the cost. At the same time, a small amount of free silicon in the ultrafine silicon carbide powder is easily hydrated to form silica sol, which improves the strength of the green body, resists the thermal stress caused by the internal and external temperature difference during the sintering process, and improves the firing qualification rate.

[0046] The preparation method of the present invention uses the honeycomb ceramic composition of the present invention, which solves the problems of difficult molding, low firing qualification rate and low strength of high porosity ultrathin wall carrier. The production process is simple and the cost is low.

[0047] Preferably, the preparation method of the present invention includes the following steps: S1. Mix the dry powders of the main component and auxiliary component to obtain a uniformly mixed powder.

[0048] These dry powders specifically include flaky narrow-particle-size talc, spherical alumina, fused spherical silica, ultrafine silicon carbide powder, and ammonium lignosulfonate carboxymethyl cellulose ammonium.

[0049] Preferably, the mass percentage of ammonium carboxymethyl cellulose ammonium lignosulfonate is 5%-8% of the total mass of the main components (flaky narrow particle size distribution of talc, spherical alumina, fused spherical silica, and ultrafine silicon carbide powder).

[0050] Preferably, this step can be carried out using an inclined high-power mixer, with a mixing time of 1-2 hours.

[0051] S2. Add lubricant and water to the well-mixed powder, and perform wet kneading to obtain mud.

[0052] Preferably, this step can be performed by using a kneader for wet mixing and kneading, with a kneading time of 60-120 minutes.

[0053] Preferably, the lubricant is a nano-grade paraffin emulsion, which accounts for 4-8% of the total mass of the main components, and the water accounts for 15-20% of the total mass of the main components.

[0054] S3. The mud is vacuumed through a mud-making machine to a vacuum degree of -0.095MPa or higher, and then made into plastic mud segments.

[0055] S4. Extrude the clay segments into a honeycomb structure at an extrusion pressure of 4-8 MPa, and microwave dry them into green bodies. Then, precisely cut the green bodies to size.

[0056] S5. Fire the green body and then perform cold processing.

[0057] The effects of the present invention will be specifically illustrated below through examples and comparative examples.

[0058] Examples 1-10 of the present invention are honeycomb ceramics prepared using the method of the present invention.

[0059] Table 1 shows the specific chemical composition, particle size, and morphology parameters of the main components used in each embodiment. Specifically, the flaky narrow-particle-size talc includes talc A1, talc A2, and talc A3; the spherical alumina includes spherical alumina C1, spherical alumina C2, and spherical alumina C3; the fused spherical silica includes fused spherical silica S1, fused spherical silica S2, and fused spherical silica S3; and the ultrafine silicon carbide powder includes ultrafine silicon carbide T1, ultrafine silicon carbide T2, and ultrafine silicon carbide T3.

[0060] SEM image of ultrafine silicon carbide T1 is shown below Figure 1 As shown. SEM image of molten spherical alumina C1. Figure 2 As shown, the SEM image of the honeycomb ceramic in Example 7 is as follows. Figure 3 As shown.

[0061] Loss on ignition (LOI) of flaky, narrow-particle-size talc refers to the percentage of weight lost by the raw material dried at 105-110℃ after ignition at 1000-1100℃. The components lost on ignition are mainly those decomposed by heat, such as water or carbon dioxide, and also include some organic matter. In this invention, the loss on ignition is mainly water of crystallization.

[0062] Table 2 shows the mass percentage of each specific component in the main components used in each embodiment. Among them, lignoammonium refers to ammonium carboxymethyl cellulose sulfonate, and paraffin emulsion refers to nano-sized paraffin emulsion. The mass percentage of both and water is calculated as 100% of the total mass of flaky narrow-particle-size talc, spherical alumina, molten spherical silica, and ultrafine silicon carbide micropowder.

[0063] Comparative Example 1 uses a conventional method for synthesizing cordierite. Its composition is as follows: 41.35% flaky talc, 42.95% flaky kaolin, 15.69% alumina, 42% starch pore-forming agent, 9.5% high viscosity (6000-10000 mPa.s) HPMC, and 8% fatty acid. The mass percentages of pore-forming agent, HPMC, and fatty acid are based on the total mass of flaky talc, flaky kaolin, and alumina.

[0064] In addition, the flaky talc in Comparative Example 1 has a Fe2O3 mass percentage of 0.2%, an aspect ratio of 5, and a particle size D. 97 Greater than 35 μm. The alumina is non-spherical, meaning its sphericity is less than 70%.

[0065] Table 1 Principal component parameters for each embodiment Table 2 Ingredient proportions for each embodiment Table 3 Comparison of properties of high-porosity, high-strength, ultrathin-walled cordierite honeycomb ceramics As can be seen from Examples 1-10, as the pore density increases and the wall thickness decreases, the extrusion pressure increases. Under the same pore density and wall thickness, the finer the raw material particle size, the lower the extrusion pressure, which can still meet the requirement of 4-8 MPa. This is because the finer the raw material particle size, the larger the specific surface area and the worse the flowability. However, the finer the raw material, the finer the median pore size and the higher the carrier strength. At the same time, as the specific surface area increases, the reactivity increases, making it easier to synthesize cordierite, reducing the coefficient of thermal expansion and improving the thermal shock performance. Meanwhile, as the particle size of flaky narrow-particle-size high-iron-content talc, spherical alumina, fused spherical silica and ultrafine silicon carbide increases, the porosity increases, reaching up to 67.99%. However, the coefficient of thermal expansion increases, but all remain below 0.35×10-6. At the same time, it meets the requirement of not cracking after three thermal shocks at 750℃, and its performance is far superior to that of Comparative Example 1.

[0066] Meanwhile, using ultrafine silicon carbide as a pore-forming agent results in a strong pore-forming ability. With only 13% added, the carrier porosity reaches over 67%, while the median pore size can be controlled between 1.0-6.0 μm. The carrier A-axis strength is also relatively high, reaching over 3.5 MPa.

[0067] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A high-porosity, high-strength, ultra-thin-walled cordierite honeycomb ceramic, characterized in that, The main components of the honeycomb ceramic include flaky narrow-particle-size talc, spherical alumina, molten spherical silica, and a pore-forming agent; In the flaky, narrow-particle-size talc, the mass percentage of Fe2O3 is greater than or equal to 1.5%, the aspect ratio is greater than or equal to 10, and the particle size D is... 97 Less than or equal to 30 μm; The sphericity of both the spherical alumina and the molten spherical silica is greater than or equal to 98%, and the mass percentage of the amorphous phase in the molten spherical silica is greater than or equal to 99.5%. The pore-forming agent is ultrafine silicon carbide powder.

2. The high-porosity, high-strength, ultra-thin-walled cordierite honeycomb ceramic according to claim 1, characterized in that, In the flaky, narrow-particle-size talc, the mass percentage of silicon dioxide is greater than or equal to 57.0%, the mass percentage of magnesium oxide is greater than or equal to 29.0%, the mass percentage of calcium oxide is less than or equal to 0.2%, and the particle size D... 50 The particle size is 11-17 μm, D. 97 Less than or equal to 25μm.

3. The high-porosity, high-strength, ultra-thin-walled cordierite honeycomb ceramic according to claim 1, characterized in that, The particle size D of the spherical alumina 50 The particle size is 0.4-5.0 μm, with a particle size D. 97 The alumina is less than or equal to 10 μm and has a mass percentage of 99.50%.

4. The high-porosity, high-strength, ultra-thin-walled cordierite honeycomb ceramic according to claim 1, characterized in that, The particle size D of the molten spherical silica 50 The particle size is 11-17 μm, D. 97 Less than or equal to 25μm.

5. The high-porosity, high-strength, ultra-thin-walled cordierite honeycomb ceramic according to claim 1, characterized in that, The particle size D of the ultrafine silicon carbide powder 50 The particle size is 0.4-4.0 μm, and the particle size D is... 97 The size is less than or equal to 15 μm, the mass percentage of calcium oxide is less than or equal to 0.2%, and the total mass percentage of potassium oxide and sodium oxide is less than 0.5%.

6. A high-porosity, high-strength, ultra-thin-walled cordierite honeycomb ceramic according to any one of claims 1-5, characterized in that, In the main components, the mass percentage of flaky narrow-particle-size talc is 41.80%-46.06%, the mass percentage of spherical alumina is 34.60%-36.04%, the mass percentage of molten spherical silica is 5.83%-18.58%, and the mass percentage of ultrafine silicon carbide powder is 5%-13%.

7. A high-porosity, high-strength, ultra-thin-walled cordierite honeycomb ceramic according to any one of claims 1-5, characterized in that, The honeycomb ceramic also includes a binder, which is low-viscosity ammonium lignosulfonate with a viscosity of 100-1000 mPa·s in a 2% aqueous solution at 20°C.

8. A high-porosity, high-strength, ultra-thin-walled cordierite honeycomb ceramic according to any one of claims 1-5, characterized in that, The honeycomb ceramic also includes a lubricant, which is a nano-sized paraffin emulsion with a particle size of 5-10 nm and a solid content of 60-80% by mass.

9. A method for preparing high-porosity, high-strength, ultrathin-walled cordierite honeycomb ceramic as described in any one of claims 1-8, characterized in that, The main components are used to prepare clay segments, which are then extruded, microwave-dried, and fired to obtain the honeycomb ceramic.

10. The method for preparing a high-porosity, high-strength, ultrathin-walled cordierite honeycomb ceramic according to claim 9, characterized in that, The extrusion pressure is 4-8 MPa, the firing temperature is 1400-1450℃, and the holding time during firing is 10-20 hours.

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