Inorganic lightweight ceramic microsphere material and preparation method and application thereof

Abstract

The present application relates to the technical field of ceramic microbeads, and particularly relates to an inorganic lightweight ceramic microbead material, a preparation method and application thereof.An inorganic lightweight ceramic microbead material is characterized by comprising multi-stage pore structure composite ceramic particles, and the multi-stage pore structure comprises macropores with a pore diameter of 50-150 mu m and micropores with a pore diameter of 1-10 mu m.The present application realizes the synergism of lightweight and functionalization of the material by introducing the multi-stage pore structure of macropores (50-150 mu m) and micropores (1-10 mu m).The macropores reduce the weight by reducing the density of the material, and simultaneously provide stress buffering space; the micropores reduce the thermal conductivity by limiting air convection and thermal radiation.The gradient distribution of the multi-stage pores can optimize the mechanical bearing path and avoid stress concentration.Due to the composite structure of the macropores and micropores, the lightweight and heat insulation performance of the ceramic microbead material are balanced, the multi-stage pores synergistically improve the compressive strength and heat shock resistance, and the ceramic microbead material is suitable for high-temperature heat insulation scenes.

Description

Technical Field

[0001] This invention relates to the technical field of ceramic microspheres, and in particular to an inorganic lightweight ceramic microsphere material, its preparation method, and its application. Background Technology

[0002] Ceramic microspheres are widely used in thermal insulation materials, composite material reinforcement phases, and catalyst supports due to their lightweight, low thermal conductivity, high chemical stability, and good dispersibility. Traditional methods for preparing ceramic microspheres mainly involve spray drying, high-temperature foaming, or sol-gel methods. However, these materials generally suffer from problems such as simple pore structure, low mechanical strength, and poor high-temperature stability.

[0003] To improve the mechanical and thermal insulation properties of lightweight ceramic microspheres, existing technologies mainly improve them through the following approaches:

[0004] (1) Introducing nano-reinforcing phases, such as carbon nanotubes, graphene or silicon carbide nanowires, can improve crack resistance through crack deflection mechanism, but uneven dispersion of nanoparticles can easily lead to local stress concentration.

[0005] (2) Constructing a porous structure reduces thermal conductivity and increases specific surface area. However, the pore size leads to a significant decrease in mechanical properties.

[0006] (3) Surface coating modification, such as coating the surface of microspheres with low thermal conductivity materials to form a core-shell structure by sol-gel method. Atomic layer deposition technology is used to coat the surface of alumina microspheres with nano-SiO2 layer to reduce thermal conductivity, but the bonding force between the coating layer and the substrate interface is weak and it is easy to peel off at high temperature.

[0007] Regarding the aforementioned related technologies, the inventors discovered that the existing nano-reinforced phases have poor dispersion stability, and mechanical mixing or solution impregnation methods easily lead to the agglomeration of nanoparticles, which in turn become crack sources. At the same time, high-temperature sintering leads to grain coarsening, resulting in poor strength and thermal insulation performance of the prepared ceramic microspheres. Summary of the Invention

[0008] To improve upon the shortcomings of existing ceramic microspheres in terms of poor strength and thermal insulation performance, this application provides an inorganic lightweight ceramic microsphere material, its preparation method, and its application.

[0009] In a first aspect, this application provides an inorganic lightweight ceramic microsphere material, which adopts the following technical solution:

[0010] An inorganic lightweight ceramic microsphere material comprises multi-level porous composite ceramic particles, wherein the multi-level porous structure includes large pores with a diameter of 50-150 μm and small pores with a diameter of 1-10 μm.

[0011] Through the above technical solution, this application achieves a synergistic effect of material lightweighting and functionalization by introducing a multi-level porous structure with macropores (50-150μm) and micropores (1-10μm). Macropores reduce weight by lowering material density while providing stress buffer space; micropores reduce thermal conductivity by limiting air convection and thermal radiation. The gradient distribution of the multi-level pores optimizes the mechanical load-bearing path and avoids stress concentration. Due to the composite structure of macropores and micropores, the lightweighting and thermal insulation performance of the ceramic microsphere material are balanced, and the multi-level pores synergistically improve compressive strength and thermal shock resistance, making it suitable for high-temperature thermal insulation applications.

[0012] Furthermore, the multi-level porous composite ceramic particles also include silicon carbide nanowires, wherein the addition ratio of silicon carbide nanowires is 0.1-0.5% of the mass of the matrix ceramic particles.

[0013] Through the above technical solution, this application selects silicon carbide nanowires as the reinforcing phase to improve the fracture toughness of the material through crack deflection, bridging, and pull-out mechanisms. The nanowires form a three-dimensional network structure in the matrix, uniformly dispersing external loads, inhibiting crack propagation, enhancing the integrity of the pore structure, avoiding the mechanical property degradation caused by large pores, and without significantly increasing the material density.

[0014] Furthermore, the matrix ceramic particles include alumina composite zirconia matrix particles and a coating shell covering the surface of the alumina composite zirconia matrix particles.

[0015] Through the above technical solution, this application uses a composite core of high-hardness, corrosion-resistant alumina and phase-transformation toughened zirconia to provide mechanical support, and a porous SiO2 shell to optimize interface properties. The core-shell structure alleviates thermal stress through a gradient design of thermal expansion coefficients, and the shell can also serve as a heat insulation or catalytic carrier functional layer, thus achieving a balance between high strength and low thermal conductivity through core-shell synergy.

[0016] Furthermore, the matrix ceramic particles are made using the following technical solution:

[0017] Alumina and zirconium oxide particles were taken and ball-milled together to obtain mixed particles;

[0018] The mixed particles are immersed in a mixture of tetraethyl orthosilicate and ethanol, ammonia is added dropwise and stirred, ultrasonically dispersed and aged, and then calcined to obtain the matrix ceramic particles.

[0019] Through the above technical solution, this application utilizes a sol-gel method to coat a uniform SiO2 layer onto the surface of mixed particles. Tetraethyl orthosilicate undergoes hydrolysis and condensation to form a gel network, with ammonia water catalyzing and controlling the reaction rate. After calcination, a porous or dense coating layer is formed. This process can achieve coatings with nanoscale thickness and controllable composition. The coating layer enhances the surface activity of the matrix particles, strengthens the interfacial bonding with subsequent slurries, and simultaneously regulates thermal and mechanical properties through the porosity of the coating layer.

[0020] Furthermore, the multi-level porous composite ceramic particles also include micropores with a pore size of 100-500 nm.

[0021] Through the above technical solution, this application introduces nanoscale micropores on the basis of existing macropores and micropores, further reducing the thermal conduction of gas molecules through the Knudsen effect. Micropores can also increase the specific surface area, providing active sites for catalytic or adsorption applications, thereby significantly improving the thermal insulation efficiency of the material while expanding its functional applications. The synergistic effect of multi-level pores optimizes the overall performance.

[0022] Secondly, this application provides a method for preparing inorganic lightweight ceramic microspheres, employing the following technical solution:

[0023] A method for preparing inorganic lightweight ceramic microspheres includes the following technical steps:

[0024] The matrix ceramic particles, silicon carbide nanowires, dispersant and deionized water were stirred, mixed and ball-milled to obtain a dispersion slurry;

[0025] Take the dispersion slurry and add acrylamide, N,N'-methylenebisacrylamide and ammonium persulfate. Stir and mix, generate droplets using a microfluidic device, and freeze dry for 24 hours.

[0026] After freeze-drying, inorganic lightweight ceramic microspheres are prepared by programmed heating and low-temperature sintering under an inert atmosphere.

[0027] Through the above technical solutions, this application preserves the porous structure by freeze-drying, avoiding the shrinkage and deformation caused by traditional drying. Low-temperature sintering, under argon protection, inhibits grain coarsening, resulting in strong overall process controllability. Freeze-drying maintains pore integrity, and low-temperature sintering reduces energy consumption and maintains the activity of the nano-reinforcing phase, ensuring the material is lightweight and has high strength.

[0028] Furthermore, the droplets generated by the microfluidic device have a particle size of 100-500 μm.

[0029] Through the above technical solution, this application adopts microfluidic technology to precisely control the droplet size through the shear force of two-phase fluid, ensuring uniform particle size of microbeads, improving batch stability of materials, avoiding thermal stress concentration or strength fluctuation caused by size differences, and is suitable for industrial production.

[0030] Furthermore, the addition ratio of the acrylamide to the matrix ceramic particles is (1-1.5):(50-55).

[0031] Through the above technical solution, this application selects acrylamide as the gel network monomer, and its addition ratio determines the rheology and curing strength of the slurry. Too low a ratio leads to insufficient gel strength, while too high a ratio hinders pore formation. By optimizing the ratio (1-1.5:50-55), the moldability and pore structure are balanced, ensuring stable molding of the slurry during the microfluidic process. At the same time, the pyrolysis of the gel network forms uniform micropores, avoiding collapse or excessive shrinkage.

[0032] Furthermore, the process of heating up and sintering at low temperature includes the following steps:

[0033] First, degrease the gas by increasing the temperature to 400℃ at a rate of 5℃ / min, then sinter it by increasing the temperature to 1400℃ at a rate of 10℃ / min, while adjusting the argon flow rate to 50mL / min.

[0034] Through the above technical solutions, this application optimizes the calcination scheme and selects a staged heating scheme to promote grain boundary diffusion densification. The degreasing stage thoroughly removes organic matter and reduces carbon residue. Nanoscale micropores are introduced on the basis of existing macropores and micropores. The Knudsen effect further reduces the thermal conductivity of gas molecules. Micropores can also increase the specific surface area and provide active sites for catalytic or adsorption applications, thereby significantly improving the thermal insulation efficiency of the material while expanding its functional applications. The synergistic effect of multi-level pores optimizes the overall performance.

[0035] Thirdly, this application discloses an application of an inorganic lightweight ceramic microsphere material, employing the following technical solution:

[0036] An application of an inorganic lightweight ceramic microsphere material involves adding the prepared inorganic lightweight ceramic microsphere material to a resin material as a reinforcing thermal insulation material.

[0037] Through the above technical solution, this application incorporates microspheres as fillers into the resin matrix, utilizing their low density and low thermal conductivity to reduce the overall density and thermal conductivity of the composite material. The reinforcing effect of the microspheres can also improve the mechanical properties of the resin, thus enabling the prepared composite material to possess lightweight, high strength, and excellent thermal insulation properties, making it suitable for aerospace, electronic packaging, and other fields, thereby expanding the application scenarios of ceramic microspheres.

[0038] In summary, this application has the following beneficial effects:

[0039] First, this application achieves a synergistic effect of material lightweighting and functionalization by introducing a multi-level porous structure with macropores (50-150 μm) and micropores (1-10 μm). Macropores reduce weight by lowering material density while providing stress buffer space; micropores reduce thermal conductivity by limiting air convection and thermal radiation. The gradient distribution of the multi-level pores optimizes the mechanical load-bearing path and avoids stress concentration. Due to the composite structure of macropores and micropores, the lightweighting and thermal insulation performance of the ceramic microsphere material are balanced, and the multi-level pores synergistically improve compressive strength and thermal shock resistance, making it suitable for high-temperature thermal insulation applications.

[0040] Secondly, this application uses a composite core of high-hardness, corrosion-resistant alumina and phase-transformed toughened zirconia to provide mechanical support, while the surface is coated with a porous SiO2 shell to optimize interface properties. The core-shell structure alleviates thermal stress through a gradient design of the coefficient of thermal expansion, and the shell can also serve as a heat insulation or catalytic carrier functional layer, thus achieving a balance between high strength and low thermal conductivity through core-shell synergy.

[0041] Third, this application optimizes the calcination scheme and adopts a staged heating technology to promote grain boundary diffusion densification. It thoroughly removes organic matter and reduces carbon residue through the degreasing stage. It introduces nanoscale micropores on the basis of existing macropores and micropores, and further reduces the thermal conductivity of gas molecules through the Knudsen effect. The micropores can also increase the specific surface area and provide active sites for catalytic or adsorption applications, thereby significantly improving the thermal insulation efficiency of the material and expanding its functional applications. The synergistic effect of multi-level pores optimizes the overall performance.

[0042] Fourth, this application selects acrylamide as the gel network monomer, and its addition ratio determines the rheological properties and curing strength of the slurry. Too low a ratio leads to insufficient gel strength, while too high a ratio hinders pore formation. By optimizing the ratio (1-1.5:50-55), the moldability and pore structure are balanced to ensure stable molding of the slurry during the microfluidic process. At the same time, the pyrolysis of the gel network forms uniform micropores, avoiding collapse or excessive shrinkage. Detailed Implementation

[0043] The present application will be further described in detail below with reference to the embodiments.

[0044] Preparation Example 1

[0045] Matrix ceramic particles 1

[0046] Alumina and zirconium oxide particles were mixed at a mass ratio of 6:4 and ball-milled at a ball-to-particle ratio of 10:1 at a speed of 400 rpm using anhydrous ethanol as the medium. The mixed particles were collected. The mixed particles were then immersed in a mixture of tetraethyl orthosilicate and ethanol at a molar ratio of 1:4. After adjusting the pH to 9.0 by adding 0.1 mol of ammonia, the particles were ultrasonically dispersed at 200 W and aged for 24 h. The aged particles were then calcined at 500 °C for 2 h to obtain the matrix ceramic particles 1.

[0047] Preparation Example 2

[0048] Matrix ceramic particles 2

[0049] Alumina and zirconium oxide particles were mixed at a mass ratio of 6:4 and ball-milled at a ball-to-particle ratio of 10:1 at a speed of 400 rpm using anhydrous ethanol as the medium. The mixed particles were collected and calcined at 500℃ for 2 hours to prepare matrix ceramic particles 2.

[0050] Example 1

[0051] An inorganic lightweight ceramic microsphere material comprises multi-level porous composite ceramic particles, wherein the multi-level porous structure includes large pores with a diameter of 50-150 μm and small pores with a diameter of 1-10 μm.

[0052] A method for preparing inorganic lightweight ceramic microspheres includes the following preparation steps:

[0053] Take 100 kg of matrix ceramic particles 1 and add them to 0.5 kg of polyvinyl alcohol solution with a mass fraction of 8%, and disperse them by ultrasonication at 200 W to form a dispersion slurry.

[0054] Take the dispersion slurry and add 1 kg of acrylamide, 0.1 kg of N,N'-methylenebisacrylamide and 0.05 kg of ammonium persulfate. Stir and mix, and use a microfluidic device to generate droplets with a particle size of 200 μm. After quick freezing with liquid nitrogen, freeze dry for 24 h and collect the preform.

[0055] The preform is placed in a tube furnace and degreased at 400℃ for 1 hour under argon protection by heating at 5℃ / min. Then, it is sintered at 1400℃ for 30 minutes by heating at 10℃ / min to obtain inorganic lightweight ceramic microspheres.

[0056] Example 2

[0057] An inorganic lightweight ceramic microsphere material comprises multi-level porous composite ceramic particles, wherein the multi-level porous structure includes large pores with a diameter of 50-150 μm and small pores with a diameter of 1-10 μm.

[0058] A method for preparing inorganic lightweight ceramic microspheres includes the following preparation steps:

[0059] Take 100 kg of matrix ceramic particles 1 and add them to 0.5 kg of polyvinyl alcohol solution with a mass fraction of 8%, and disperse them by ultrasonication at 200 W to form a dispersion slurry.

[0060] Take the dispersion slurry and add 1.8 kg acrylamide, 0.1 kg N,N'-methylenebisacrylamide and 0.05 kg ammonium persulfate. Stir and mix, and use a microfluidic device to generate droplets with a particle size of 300 μm. After quick freezing with liquid nitrogen, freeze dry for 24 h and collect the preform.

[0061] The preform is placed in a tube furnace and degreased at 400℃ for 1 hour under argon protection by heating at 5℃ / min. Then, it is sintered at 1400℃ for 30 minutes by heating at 10℃ / min to obtain inorganic lightweight ceramic microspheres.

[0062] Example 3

[0063] An inorganic lightweight ceramic microsphere material comprises multi-level porous composite ceramic particles, wherein the multi-level porous structure includes large pores with a diameter of 50-150 μm and small pores with a diameter of 1-10 μm.

[0064] A method for preparing inorganic lightweight ceramic microspheres includes the following preparation steps:

[0065] Take 100 kg of matrix ceramic particles 1 and add them to 0.5 kg of polyvinyl alcohol solution with a mass fraction of 8%, and disperse them by ultrasonication at 200 W to form a dispersion slurry.

[0066] Take the dispersion slurry and add 2.2 kg acrylamide, 0.1 kg N,N'-methylenebisacrylamide and 0.05 kg ammonium persulfate. Stir and mix, and use a microfluidic device to generate droplets with a particle size of 500 μm. After quick freezing with liquid nitrogen, freeze dry for 24 h and collect the preform.

[0067] The preform is placed in a tube furnace and degreased at 400℃ for 1 hour under argon protection by heating at 5℃ / min. Then, it is sintered at 1400℃ for 30 minutes by heating at 10℃ / min to obtain inorganic lightweight ceramic microspheres.

[0068] Example 4

[0069] An inorganic lightweight ceramic microsphere material comprises multi-level porous composite ceramic particles, wherein the multi-level porous structure includes large pores with a diameter of 50-150 μm and small pores with a diameter of 1-10 μm.

[0070] A method for preparing inorganic lightweight ceramic microspheres includes the following preparation steps:

[0071] Take 0.1 kg of silicon carbide nanowires and 100 kg of matrix ceramic particles 1 and stir to mix. Add 0.5 kg of 8% polyvinyl alcohol solution and disperse by ultrasonication at 200 W to form a dispersion slurry.

[0072] Take the dispersion slurry and add 1 kg of acrylamide, 0.1 kg of N,N'-methylenebisacrylamide and 0.05 kg of ammonium persulfate. Stir and mix, and use a microfluidic device to generate droplets with a particle size of 200 μm. After quick freezing with liquid nitrogen, freeze dry for 24 h and collect the preform.

[0073] The preform is placed in a tube furnace and degreased at 400℃ for 1 hour under argon protection by heating at 5℃ / min. Then, it is sintered at 1400℃ for 30 minutes by heating at 10℃ / min to obtain inorganic lightweight ceramic microspheres.

[0074] Example 5

[0075] An inorganic lightweight ceramic microsphere material comprises multi-level porous composite ceramic particles, wherein the multi-level porous structure includes large pores with a diameter of 50-150 μm and small pores with a diameter of 1-10 μm.

[0076] A method for preparing inorganic lightweight ceramic microspheres includes the following preparation steps:

[0077] Take 0.2 kg of silicon carbide nanowires and 100 kg of matrix ceramic particles 1 and stir to mix. Add 0.5 kg of 8% polyvinyl alcohol solution and disperse by ultrasonication at 200 W to form a dispersion slurry.

[0078] Take the dispersion slurry and add 1.8 kg acrylamide, 0.1 kg N,N'-methylenebisacrylamide and 0.05 kg ammonium persulfate. Stir and mix, and use a microfluidic device to generate droplets with a particle size of 300 μm. After quick freezing with liquid nitrogen, freeze dry for 24 h and collect the preform.

[0079] The preform is placed in a tube furnace and degreased at 400℃ for 1 hour under argon protection by heating at 5℃ / min. Then, it is sintered at 1400℃ for 30 minutes by heating at 10℃ / min to obtain inorganic lightweight ceramic microspheres.

[0080] Example 6

[0081] An inorganic lightweight ceramic microsphere material comprises multi-level porous composite ceramic particles, wherein the multi-level porous structure includes large pores with a diameter of 50-150 μm and small pores with a diameter of 1-10 μm.

[0082] A method for preparing inorganic lightweight ceramic microspheres includes the following preparation steps:

[0083] Take 0.5 kg of silicon carbide nanowires and 100 kg of matrix ceramic particles 1 and stir to mix. Add 0.5 kg of polyvinyl alcohol solution with a mass fraction of 8% and disperse by ultrasonication at 200 W to form a dispersion slurry.

[0084] Take the dispersion slurry and add 2.2 kg acrylamide, 0.1 kg N,N'-methylenebisacrylamide and 0.05 kg ammonium persulfate. Stir and mix, and use a microfluidic device to generate droplets with a particle size of 500 μm. After quick freezing with liquid nitrogen, freeze dry for 24 h and collect the preform.

[0085] The preform is placed in a tube furnace and degreased at 400℃ for 1 hour under argon protection by heating at 5℃ / min. Then, it is sintered at 1400℃ for 30 minutes by heating at 10℃ / min to obtain inorganic lightweight ceramic microspheres.

[0086] Example 7

[0087] An inorganic lightweight ceramic microsphere material comprises multi-level porous composite ceramic particles, wherein the multi-level porous structure includes large pores with a diameter of 50-150 μm and small pores with a diameter of 1-10 μm.

[0088] A method for preparing inorganic lightweight ceramic microspheres includes the following preparation steps:

[0089] Take 0.5 kg of silicon carbide nanowires and 100 kg of matrix ceramic particles 2 and stir to mix. Add 0.5 kg of polyvinyl alcohol solution with a mass fraction of 8% and disperse by ultrasonication at 200 W to form a dispersion slurry.

[0090] Take the dispersion slurry and add 1.8 kg acrylamide, 0.1 kg N,N'-methylenebisacrylamide and 0.05 kg ammonium persulfate. Stir and mix, and use a microfluidic device to generate droplets with a particle size of 300 μm. After quick freezing with liquid nitrogen, freeze dry for 24 h and collect the preform.

[0091] The preform is placed in a tube furnace and degreased at 400℃ for 1 hour under argon protection by heating at 5℃ / min. Then, it is sintered at 1400℃ for 30 minutes by heating at 10℃ / min to obtain inorganic lightweight ceramic microspheres.

[0092] Example 8

[0093] An inorganic lightweight ceramic microsphere material comprises multi-level porous composite ceramic particles, wherein the multi-level porous structure includes large pores with a diameter of 50-150 μm and small pores with a diameter of 1-10 μm.

[0094] A method for preparing inorganic lightweight ceramic microspheres includes the following preparation steps:

[0095] Take 0.5 kg of silicon carbide nanowires and 100 kg of matrix ceramic particles 2 and stir to mix. Add 0.5 kg of polyvinyl alcohol solution with a mass fraction of 8% and disperse by ultrasonication at 200 W to form a dispersion slurry.

[0096] Take the dispersion slurry and add 1.8 kg acrylamide, 0.1 kg N,N'-methylenebisacrylamide and 0.05 kg ammonium persulfate. Stir and mix, and use a microfluidic device to generate droplets with a particle size of 300 μm. After quick freezing with liquid nitrogen, freeze dry for 24 h and collect the preform.

[0097] Inorganic lightweight ceramic microspheres can be prepared by placing the preform in a tube furnace and sintering it at 1400℃ for 30 minutes.

[0098] Performance testing

[0099] The inorganic lightweight ceramic microspheres prepared in Examples 1-8 were used as modifying materials. 100 kg of epoxy resin E511, 80 kg of curing agent, 1 kg of accelerator, and 20 kg of inorganic lightweight ceramic microspheres were taken. First, the epoxy resin E511 was preheated to 40°C to reduce viscosity. Then, the curing agent and accelerator were added sequentially, and the mixture was magnetically stirred for 10 min until homogeneous. The modified ceramic microspheres were added in batches, and the mixture was mechanically stirred at a low speed of 200 rpm to avoid bubble formation. The mixing time was 20 min, and vacuum degassing was performed at -0.1 MPa for 30 min until no visible bubbles remained in the slurry. A silicone mold coated with a release agent was pre-cured at 80°C for 2 h, then post-cured at 120°C for 4 h. After natural cooling to room temperature, the epoxy resin material was collected.

[0100] The performance of epoxy resin materials prepared using the inorganic lightweight ceramic microspheres prepared in Examples 1-8 as modified materials was tested. The compressive strength was tested according to the test standard ASTM D695. At the same time, the thermal conductivity of the above materials was tested. The material without the addition of inorganic lightweight ceramic microspheres was set as the control group.

[0101] Table 1 Performance Test Table

[0102]

[0103]

[0104] A comparison of the results from Examples 1-8 and the control group reveals that:

[0105] Examples 1-3 illustrate how this application achieves a synergistic effect of material lightweighting and functionalization by introducing a multi-level porous structure with macropores (50-150 μm) and micropores (1-10 μm). Macropores reduce weight by lowering material density while providing stress buffer space; micropores reduce thermal conductivity by limiting air convection and thermal radiation. The gradient distribution of the multi-level pores optimizes the mechanical load-bearing path and avoids stress concentration. Due to the composite structure of macropores and micropores, the lightweighting and thermal insulation performance of the ceramic microsphere material are balanced. The multi-level pores synergistically enhance compressive strength and thermal shock resistance, making it suitable for high-temperature thermal insulation applications.

[0106] By comparing Examples 4-6 with Examples 1-3, this application further illustrates that silicon carbide nanowires are used as the reinforcing phase to improve the fracture toughness of the material through crack deflection, bridging, and pull-out mechanisms. The nanowires form a three-dimensional network structure in the matrix, uniformly dispersing external loads, inhibiting crack propagation, enhancing the integrity of the pore structure, avoiding the deterioration of mechanical properties caused by large pores, and without significantly increasing the material density.

[0107] By comparing Example 7 with Examples 1-6, this application further illustrates that a composite core of high-hardness, corrosion-resistant alumina and phase-transformed toughened zirconia provides mechanical support, while a porous SiO2 shell is used to optimize interface properties. The core-shell structure alleviates thermal stress through a gradient design of thermal expansion coefficients, and the shell can also serve as a heat insulation or catalytic carrier functional layer, thus achieving a balance between high strength and low thermal conductivity through core-shell synergy.

[0108] Finally, by comparing Examples 7 and 8, it is further illustrated that this application promotes grain boundary diffusion densification by optimizing the calcination scheme and selecting a staged heating technology. It thoroughly removes organic matter and reduces carbon residue through the degreasing stage. It introduces nanoscale micropores on the basis of existing macropores and micropores, further reducing the thermal conductivity of gas molecules through the Knudsen effect. The micropores can also increase the specific surface area and provide active sites for catalytic or adsorption applications, thereby significantly improving the thermal insulation efficiency of the material while expanding its functional applications. The synergistic effect of multi-level pores optimizes the overall performance.

[0109] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0110] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0111] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0112] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

Claims

1. An inorganic lightweight ceramic microsphere material, characterized in that, The composite ceramic particles include a hierarchical porous structure, wherein the hierarchical porous structure comprises large pores with a diameter of 50-150 μm and small pores with a diameter of 1-10 μm; the composite ceramic particles also include silicon carbide nanowires, wherein the addition ratio of silicon carbide nanowires is 0.1-0.5% of the mass of the matrix ceramic particles; The inorganic lightweight ceramic microsphere material is prepared by the following method, including the following preparation steps: The matrix ceramic particles, silicon carbide nanowires, dispersant and deionized water were stirred, mixed and ball-milled to obtain a dispersion slurry; Take the dispersion slurry and add acrylamide, N,N'-methylenebisacrylamide and ammonium persulfate. Stir and mix, generate droplets using a microfluidic device, and freeze dry for 24 hours. After freeze-drying, the inorganic lightweight ceramic microspheres are prepared by programmed heating and low-temperature sintering under an inert atmosphere; the matrix ceramic particles include alumina composite zirconia matrix particles and a silica coating shell covering the surface of the alumina composite zirconia matrix particles.

2. The inorganic lightweight ceramic microsphere material according to claim 1, characterized in that, The matrix ceramic particles are made using the following technical solution: Alumina and zirconium oxide particles were taken and ball-milled together to obtain mixed particles; The mixed particles are immersed in a mixture of tetraethyl orthosilicate and ethanol, ammonia is added dropwise and stirred, ultrasonically dispersed and aged, and then calcined to obtain the matrix ceramic particles.

3. The inorganic lightweight ceramic microsphere material according to claim 1, characterized in that, The multi-level porous composite ceramic particles also include micropores with a pore size of 100-500 nm.

4. The inorganic lightweight ceramic microsphere material according to claim 1, characterized in that, The droplets generated by the flow control device have a particle size of 100-500 μm.

5. The inorganic lightweight ceramic microsphere material according to claim 1, characterized in that, The addition ratio of acrylamide to the matrix ceramic particles is (1-1.5):(50-55).

6. The inorganic lightweight ceramic microsphere material according to claim 1, characterized in that, The process of heating up and low-temperature sintering includes the following steps: First, degrease the gas by increasing the temperature to 400℃ at a rate of 5℃ / min, then sinter it by increasing the temperature to 1400℃ at a rate of 10℃ / min, while adjusting the argon flow rate to 50mL / min.

7. An application of an inorganic lightweight ceramic microsphere material, characterized in that, The inorganic lightweight ceramic microsphere material of any one of claims 1-6 is added to the resin material as a reinforcing thermal insulation material.

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