Inorganic lightweight ceramic microbead material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of ceramic microbeads, in particular to an inorganic lightweight ceramic microbead material as well as a preparation method and application thereof. The inorganic lightweight ceramic microbead material is characterized in that the inorganic lightweight ceramic microbead material comprises multi-stage pore structure composite ceramic particles, and the multi-stage pore structure comprises large pores with the pore diameter of 50-150 [mu] m and small pores with the pore diameter of 1-10 [mu] m. According to the invention, by introducing a multi-stage pore structure with macropores (50-150 [mu] m) and micropores (1-10 [mu] m), the synergism of lightweight and functionalization of the material is realized. The macropores reduce the weight by reducing the material density, and provide a stress buffer space at the same time; the small holes reduce the heat conductivity coefficient by limiting air convection and heat radiation. The gradient distribution of the multi-stage pores can optimize a mechanical bearing path and avoid stress concentration. Due to the composite structure of macropores and small pores, the lightweight and heat-insulating properties of the ceramic microbead material are balanced, and the compressive strength and the thermal shock resistance are synergistically improved by the multistage pores, so that the material is suitable for high-temperature heat-insulating scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic microspheres, and particularly to an inorganic lightweight ceramic microsphere material, a preparation method thereof, and an application thereof. Background Art

[0002] Ceramic microsphere materials are widely used in the fields of thermal insulation materials, composite material reinforcing phases, catalytic carriers, etc. due to their light weight, low thermal conductivity, high chemical stability, and good dispersibility. The preparation of traditional ceramic microspheres is mainly achieved through spray drying, high-temperature foaming, or sol-gel methods. However, such materials generally have problems such as a single pore structure, low mechanical strength, and poor high-temperature stability.

[0003] In order to improve the mechanical and thermal insulation properties of lightweight ceramic microspheres, the prior art mainly improves through the following ways:

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

[0005] (2) Constructing a pore structure to reduce the thermal conductivity and increase the specific surface area through the pore structure. However, its pore size causes a significant decrease in mechanical properties;

[0006] (3) Surface coating modification, such as coating a low-thermal-conductivity material on the surface of microspheres through the sol-gel method to form a core-shell structure. Using atomic layer deposition technology to coat a nano-SiO2 layer on the surface of alumina microspheres reduces the thermal conductivity, but the interfacial bonding force between the coating layer and the matrix is weak and is easily peeled off at high temperatures.

[0007] In view of the above related technologies, the inventor found that the dispersion stability of the existing nano-reinforcing phases is poor, and mechanical mixing or solution impregnation methods easily lead to agglomeration of nano-particles, which instead 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] In order to improve the defects of poor strength and thermal insulation performance of existing ceramic microspheres, the present application provides an inorganic lightweight ceramic microsphere material, a preparation method thereof, and an application thereof.

[0009] In the first aspect, the present application provides an inorganic lightweight ceramic microsphere material, adopting the following technical solution:

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

[0011] Through the above technical solutions, this application realizes the coordination of lightweight and functionalization of materials by introducing a multi-level pore structure with macropores (50 - 150 μm) and micropores (1 - 10 μm). The macropores reduce the weight by decreasing the material density and provide stress buffer space at the same time; the micropores reduce the thermal conductivity by restricting air convection and heat radiation. The gradient distribution of the multi-level pores can optimize the mechanical load-bearing path and avoid stress concentration. Due to the composite structure of the large pores and small pores, the lightweight and heat insulation performance of the ceramic microsphere material are balanced, and the multi-level pores synergistically improve the compressive strength and thermal shock resistance, which is suitable for high-temperature heat insulation scenarios.

[0012] Furthermore, the multi-level pore structure composite ceramic particles further include silicon carbide nanowires, and the addition ratio of the silicon carbide nanowires is 0.1 - 0.5% of the mass of the matrix ceramic particles.

[0013] Through the above technical solutions, this application selects silicon carbide nanowires as the reinforcing phase and improves the fracture toughness of the material through crack deflection, bridging, and pulling-out mechanisms. The nanowires form a three-dimensional network structure in the matrix, uniformly disperse the external load, inhibit crack propagation, enhance the integrity of the pore structure, avoid the deterioration of mechanical properties caused by macropores, and do not significantly increase the material density.

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

[0015] Through the above technical solutions, this application selects a composite core of high-hardness and corrosion-resistant alumina and phase transformation toughened zirconia to provide mechanical support, and a porous SiO2 shell on the surface to optimize the interface characteristics. The core-shell structure relieves thermal stress through the design of the thermal expansion coefficient gradient, and the shell can also be used as a heat insulation or catalytic carrier functional layer, thus realizing the unity of high strength and low thermal conductivity through the coordination of the core and shell.

[0016] Furthermore, the matrix ceramic particles are prepared by the following technical solutions:

[0017] Take alumina and zirconia particles and ball-mill and mix them, and collect the mixed particles;

[0018] Immerse the mixed particles in a mixed solution of tetraethyl orthosilicate and ethanol, add ammonia water and stir and mix, ultrasonically disperse and age, and perform calcination treatment to prepare the matrix ceramic particles.

[0019] Through the above technical solution, in this application, a uniform SiO2 layer is coated on the surface of the mixed particles by the sol-gel method. Tetraethyl orthosilicate hydrolyzes and polycondenses to form a gel network, and ammonia water catalysis is used to control the reaction rate. After calcination, a porous or dense coating layer is formed. This process can achieve coatings with a controllable nanoscale thickness and composition. The coating layer improves the surface activity of the matrix particles, enhances the interfacial bonding with the subsequent slurry, and simultaneously regulates the thermal and mechanical properties through the pores of the coating layer.

[0020] Further, the multi-level pore structure composite ceramic particles further include micropores with a pore diameter of 100-500 nm.

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

[0022] In a second aspect, this application provides a preparation method for an inorganic lightweight ceramic microsphere material, adopting the following technical solution:

[0023] A preparation method for an inorganic lightweight ceramic microsphere material includes the following technical steps:

[0024] Take matrix ceramic particles, silicon carbide nanowires, a dispersant, and deionized water, stir and mix them, and perform ball milling treatment to collect a dispersed slurry;

[0025] Take the dispersed slurry, add acrylamide, N,N'-methylenebisacrylamide, and ammonium persulfate, stir and mix them. A microfluidic device generates droplets, and freeze-dry for 24 h;

[0026] After the freeze-drying is completed, raise the temperature programmatically under an inert atmosphere and perform low-temperature sintering to prepare the inorganic lightweight ceramic microsphere material.

[0027] Through the above technical solution, in this application, the porous structure is retained by freeze-drying, avoiding shrinkage and deformation during traditional drying. Low-temperature sintering suppresses grain coarsening under argon protection. The overall preparation process has strong controllability. Freeze-drying maintains the integrity of the pores, and low-temperature sintering reduces energy consumption and maintains the activity of the nano-reinforcing phase, ensuring the light weight and high strength of the material.

[0028] Further, 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 fluids, ensuring uniform microsphere particle size, improving the batch stability of the material, avoiding thermal stress concentration or strength fluctuations caused by size differences, and being 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, acrylamide is selected as the gel network monomer in this application, and its addition ratio determines the rheology and curing strength of the slurry. If the ratio is too low, the gel strength is insufficient; if it is too high, the formation of pores is hindered. By optimizing the ratio (1 - 1.5:50 - 55), the formability and pore structure are balanced to ensure that the slurry is stably formed 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 programmed temperature rise and low-temperature sintering include the following steps:

[0033] First, it is heated to 400 °C at a rate of 5 °C / min for degreasing treatment, and then heated to 1400 °C at a rate of 10 °C / min for sintering, and the argon flow rate is adjusted to 50 mL / min.

[0034] Through the above technical solution, in this application, by optimizing the calcination scheme and selecting the technical solution of staged temperature rise, the densification of grain boundary diffusion is promoted. The organic matter is completely removed during the degreasing stage, reducing carbon residue. Nanoscale micropores are introduced on the basis of the existing macropores and micropores. The Knudsen effect is used to further reduce the heat conduction of gas molecules. The micropores can also increase the specific surface area, providing active sites for catalytic or adsorption applications, thereby significantly improving the heat insulation efficiency of the material and expanding its functional applications. The synergistic effect of multi-level pores optimizes the comprehensive performance.

[0035] In the third aspect, this application discloses an application of an inorganic lightweight ceramic microsphere material, adopting the following technical solution:

[0036] An application of an inorganic lightweight ceramic microsphere material, adding the above-prepared inorganic lightweight ceramic microsphere material to a resin material as a reinforcing heat insulation material.

[0037] Through the above technical solution, in this application, the microspheres are added as fillers to the resin matrix, and their low density and low thermal conductivity are used to reduce the overall density and thermal conductivity of the composite material. The strengthening effect of the microspheres can also improve the mechanical properties of the resin, so that the prepared composite material has both light weight, high strength and excellent heat insulation, and is suitable for fields such as aerospace and electronic packaging, expanding the application scenarios of ceramic microspheres.

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

[0039] First, by introducing a multi-level pore structure consisting of macropores (50 - 150 μm) and micropores (1 - 10 μm), this application achieves the synergy of material lightweighting and functionalization. Macropores reduce weight by lowering the material density and simultaneously provide stress buffering space; micropores reduce the thermal conductivity by restricting air convection and thermal radiation. The gradient distribution of the multi-level pores can optimize the mechanical load-bearing path and avoid stress concentration. Due to the composite structure of macropores and micropores, the lightweighting and heat insulation performance of the ceramic microsphere material are balanced, and the multi-level pores synergistically enhance the compressive strength and thermal shock resistance, making it suitable for high-temperature heat insulation scenarios.

[0040] Second, this application selects a composite core of high-hardness and corrosion-resistant alumina and phase transformation toughened zirconia to provide mechanical support, and a porous SiO2 shell is coated on the surface to optimize the interfacial properties. The core-shell structure alleviates thermal stress through the design of the thermal expansion coefficient gradient, and the shell can also serve as a functional layer for heat insulation or catalysis carrier, thus achieving the unity of high strength and low thermal conductivity through the synergy of the core and shell.

[0041] Third, by optimizing the calcination scheme and selecting a technical scheme of staged temperature rise, this application promotes grain boundary diffusion densification, completely removes organic matter in the degreasing stage, reduces carbon residue, introduces nanoscale micropores on the basis of existing macropores and micropores, further reduces the thermal conduction of gas molecules through the Knudsen effect, and the micropores can also increase the specific surface area and provide active sites for catalytic or adsorption applications, thus significantly improving the heat insulation efficiency of the material while expanding its functional applications, and the synergistic effect of the multi-level pores optimizes the comprehensive performance.

[0042] Fourth, 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 results in insufficient gel strength, while too high a ratio hinders pore formation. By optimizing the ratio (1 - 1.5:50 - 55), the formability and pore structure are balanced to ensure stable forming of the slurry during the microfluidic process. At the same time, the thermal decomposition of the gel network forms uniform micropores, avoiding collapse or excessive shrinkage. Detailed implementation mode

[0043] The following further elaborates on this application in combination with examples.

[0044] Preparation Example 1

[0045] Matrix ceramic particle 1

[0046] Take alumina and zirconia particles, mix them according to a mass ratio of 6:4, use anhydrous ethanol as the medium, and carry out ball milling and mixing at a ball-to-material ratio of 10:1 and a ball milling rate of 400 rpm. Collect the mixed particles; immerse the mixed particles in a mixed solution of tetraethyl orthosilicate and ethanol mixed according to a molar ratio of 1:4, add 0.1 mol of ammonia water to adjust the pH to 9.0, then disperse ultrasonically at 200 W and age for 24 h. The aged particles are calcined at 500 °C for 2 h to prepare matrix ceramic particle 1.

[0047] Preparation Example 2

[0048] Matrix ceramic particles 2

[0049] Take alumina and zirconia particles, mix them according to a mass ratio of 6:4, use anhydrous ethanol as the medium, and perform ball milling and mixing at a ball-to-material ratio of 10:1 and a ball milling rate of 400 rpm. Collect the mixed particles; take the mixed particles and calcine them at 500 °C for 2 h to obtain matrix ceramic particles 2.

[0050] Example 1

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

[0052] A preparation method of an inorganic lightweight ceramic microsphere material, comprising the following preparation steps:

[0053] Take 100 kg of matrix ceramic particles 1 and add them to 0.5 kg of a polyvinyl alcohol solution with a mass fraction of 8%. Perform ultrasonic dispersion 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. Quick-freeze with liquid nitrogen and then freeze-dry for 24 h to collect the preform.

[0055] Place the preform in a tube furnace, heat it to 400 °C at a rate of 5 °C / min under argon protection for 1 h for debinding, and then heat it to 1400 °C at a rate of 10 °C / min for sintering for 30 min to obtain the inorganic lightweight ceramic microsphere material.

[0056] Example 2

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

[0058] A preparation method of an inorganic lightweight ceramic microsphere material, comprising the following preparation steps:

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

[0060] Take the dispersion slurry and add 1.8 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 300 μm. Quick-freeze with liquid nitrogen and then freeze-dry for 24 h to collect the preform.

[0061] Place the preform in a tube furnace, heat it to 400 °C at a rate of 5 °C / min under argon protection for 1 h of debinding, and then heat it to 1400 °C at a rate of 10 °C / min for 30 min of sintering to prepare the inorganic lightweight ceramic microsphere material.

[0062] Example 3

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

[0064] A preparation method of an inorganic lightweight ceramic microsphere material, comprising the following preparation steps:

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

[0066] Take the dispersion slurry and add 2.2 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 500 μm. Quick-freeze with liquid nitrogen and then freeze-dry for 24 h to collect the preform.

[0067] Place the preform in a tube furnace, heat it to 400 °C at a rate of 5 °C / min under argon protection for 1 h of debinding, and then heat it to 1400 °C at a rate of 10 °C / min for 30 min of sintering to prepare the inorganic lightweight ceramic microsphere material.

[0068] Example 4

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

[0070] A preparation method of an inorganic lightweight ceramic microsphere material, comprising the following preparation steps:

[0071] Take 0.1 kg of silicon carbide nanowires and stir and mix them with 100 kg of matrix ceramic particles 1. Add them to 0.5 kg of a polyvinyl alcohol solution with a mass fraction of 8%. Disperse them by ultrasonic wave 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. Quick-freeze with liquid nitrogen and then freeze-dry for 24 h to collect the preform.

[0073] Place the preform in a tube furnace, heat it to 400 °C at a rate of 5 °C / min under argon protection for 1 h of debinding, and then heat it to 1400 °C at a rate of 10 °C / min for 30 min of sintering to prepare the inorganic lightweight ceramic microsphere material.

[0074] Example 5

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

[0076] A preparation method of an inorganic lightweight ceramic microsphere material, comprising the following preparation steps:

[0077] Take 0.2 kg of silicon carbide nanowires and stir and mix them with 100 kg of matrix ceramic particles 1, add them to 0.5 kg of a polyvinyl alcohol solution with a mass fraction of 8%, and disperse them by ultrasonic wave at 200 W to form a dispersion slurry.

[0078] Take the dispersion slurry and add 1.8 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 300 μm. Quick-freeze with liquid nitrogen and then freeze-dry for 24 h to collect the preform.

[0079] Place the preform in a tube furnace, heat it to 400 °C at a rate of 5 °C / min under argon protection for 1 h of debinding, and then heat it to 1400 °C at a rate of 10 °C / min for 30 min of sintering to prepare the inorganic lightweight ceramic microsphere material.

[0080] Example 6

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

[0082] A preparation method of an inorganic lightweight ceramic microsphere material, comprising the following preparation steps:

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

[0084] Take the dispersion slurry and add 2.2 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 500 μm. Quick-freeze with liquid nitrogen and then freeze-dry for 24 h to collect the preform.

[0085] Place the preform in a tubular furnace, heat it to 400 °C at a rate of 5 °C / min under argon protection for 1 h of debinding, and then heat it to 1400 °C at a rate of 10 °C / min and sinter for 30 min to prepare the inorganic lightweight ceramic microsphere material.

[0086] Example 7

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

[0088] A preparation method of an inorganic lightweight ceramic microsphere material, comprising the following preparation steps:

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

[0090] Take the dispersion slurry and add 1.8 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 300 μm. Quick-freeze with liquid nitrogen and then freeze-dry for 24 h to collect the preform.

[0091] Place the preform in a tubular furnace, heat it to 400 °C at a rate of 5 °C / min under argon protection for 1 h of debinding, and then heat it to 1400 °C at a rate of 10 °C / min and sinter for 30 min to prepare the inorganic lightweight ceramic microsphere material.

[0092] Example 8

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

[0094] A preparation method of an inorganic lightweight ceramic microsphere material, comprising the following preparation steps:

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

[0096] Take the dispersion slurry and add 1.8 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 300 μm. Quick-freeze with liquid nitrogen and then freeze-dry for 24 h to collect the preform.

[0097] Place the preform in a tubular furnace and sinter at 1400 °C for 30 min to prepare the inorganic lightweight ceramic microsphere material.

[0098] Performance testing

[0099] Using the inorganic lightweight ceramic microspheres prepared in Examples 1-8 as the modification material, take 100 kg of epoxy resin E511, 80 kg of curing agent, 1 kg of accelerator and 20 kg of inorganic lightweight ceramic microspheres. First, preheat the epoxy resin E511 to 40 °C to reduce the viscosity, then add the curing agent and accelerator in sequence, stir magnetically for 10 min until uniform, add the modified ceramic microspheres in batches, stir mechanically at a low speed of 200 rpm to avoid generating bubbles, with a mixing time of 20 min, under -0.1 MPa, vacuum degas for 30 min until there are no visible bubbles in the slurry, coat a silicone mold with a release agent, first pre-cure at 80 °C for 2 h, then post-cure at 120 °C for 4 h, and naturally cool to room temperature to collect the epoxy resin material.

[0100] Perform performance tests on the epoxy resin materials prepared with the inorganic lightweight ceramic microspheres prepared in Examples 1-8 as the modification material. Conduct compression strength tests according to the test standard ASTM D695, and at the same time test the thermal conductivity of the above materials. Set the material without adding inorganic lightweight ceramic microspheres as the control group.

[0101] Table 1 Performance test table

[0102]

[0103]

[0104] From the comparison of the results of the above Examples 1-8 and the control group, it can be found that:

[0105] Examples 1-3 illustrate that the present application realizes the coordination of material light weight and functionality by introducing a multi-level pore structure of macropores (50-150 μm) and micropores (1-10 μm). The macropores reduce the weight by decreasing the material density and at the same time provide a stress buffer space; the micropores reduce the thermal conductivity by restricting air convection and thermal radiation. The gradient distribution of the multi-level pores can optimize the mechanical load-bearing path and avoid stress concentration. Due to the composite structure of the large pores and small pores, the lightweight and heat insulation performance of the ceramic microsphere material is balanced, and the multi-level pores synergistically improve the compressive strength and thermal shock resistance, making it suitable for high-temperature heat insulation scenarios.

[0106] Comparing with Examples 4 - 6 in combination with Examples 1 - 3, it further illustrates that the present application selects silicon carbide nanowires as the reinforcing phase, and improves the fracture toughness of the material through crack deflection, bridging and pulling - out mechanisms. The nanowires form a three - dimensional network structure in the matrix, uniformly disperse the external load, inhibit crack propagation, enhance the integrity of the pore structure, avoid the deterioration of mechanical properties caused by large pores, and do not significantly increase the material density.

[0107] Comparing Example 7 with Examples 1 - 6, it further illustrates that the present application selects a composite core of alumina with high hardness and corrosion resistance and phase - transformation - toughened zirconia to provide mechanical support, and coats a porous SiO2 shell on the surface to optimize the interface characteristics. The core - shell structure alleviates thermal stress through the design of the thermal expansion coefficient gradient, and the shell can also serve as a thermal insulation or catalytic carrier functional layer, thus realizing the unity of high strength and low thermal conductivity through the synergy of the core and the shell.

[0108] Finally, comparing Example 7 with Example 8, it further illustrates that the present application promotes grain - boundary diffusion densification by optimizing the calcination scheme and selecting a technical scheme of staged heating, thoroughly removes organic matter in the degreasing stage, reduces carbon residue, introduces nano - scale micropores on the basis of existing large pores and small pores, further reduces the thermal conduction of gas molecules through the Knudsen effect, and the micropores can also increase the specific surface area, providing active sites for catalytic or adsorption applications, thus significantly improving the thermal insulation efficiency of the material while expanding its functional applications, and optimizing the comprehensive performance through the synergistic effect of multi - level pores.

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

[0110] All publications, patent applications, patents and other references mentioned in this specification are hereby incorporated 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 prefixes such as "well - known to those skilled in the art", "prior art" or their similar terms to derive materials, substances, methods, steps, devices or components, etc., the objects derived by such prefixes cover those commonly used in the art at the time when the present application is proposed, but also include those that are not commonly used at present but will become commonly recognized in the art as suitable for similar purposes.

[0112] In the context of this specification, any matter or thing not mentioned, other than what is expressly stated, shall directly apply those known in the art without any change.

Claims

1. An inorganic lightweight ceramic microsphere material, characterized in that, It includes composite ceramic particles with a multi-level pore structure, and the multi-level pore structure includes large pores with a pore diameter of 50 - 150 μm and small pores with a pore diameter of 1 - 10 μm.

2. The inorganic lightweight ceramic microsphere material according to claim 1, characterized in that The composite ceramic particles with the multi-level pore structure further include silicon carbide nanowires, and the addition ratio of the silicon carbide nanowires is 0.1 - 0.5% of the mass of the matrix ceramic particles.

3. An inorganic lightweight ceramic microsphere material according to claim 1, characterized in that, The matrix ceramic particles include alumina composite zirconia matrix particles and a coating shell coated on the surface of the alumina composite zirconia matrix particles.

4. An inorganic lightweight ceramic microsphere material according to claim 3, characterized in that, The matrix ceramic particles are prepared by the following technical scheme: Take alumina and zirconia particles and ball-mill and mix them, and collect the mixed particles; Take the mixed particles and immerse them in a mixed solution of tetraethyl orthosilicate and ethanol, dropwise add ammonia water and stir and mix, ultrasonically disperse and age, and perform calcination treatment to prepare the matrix ceramic particles.

5. An inorganic light ceramic microsphere material according to claim 1, characterized in that, The composite ceramic particles with the multi-level pore structure further include micropores with a pore diameter of 100 - 500 nm.

6. The preparation method of an inorganic lightweight ceramic microsphere material according to any one of claims 1-5, characterized in that, It includes the following preparation steps: Take the matrix ceramic particles, silicon carbide nanowires, a dispersant and deionized water, stir and mix them and perform ball-milling treatment, and collect the dispersed slurry; Take the dispersed slurry and add acrylamide, N,N'-methylenebisacrylamide and ammonium persulfate, stir and mix them, generate droplets with a microfluidic device, and freeze-dry for 24 h; After the freeze-drying is completed, raise the temperature programatically under an inert atmosphere and perform low-temperature sintering to prepare the inorganic lightweight ceramic microsphere material.

7. The preparation method of an inorganic lightweight ceramic microsphere material according to claim 6, characterized in that, The droplets generated by the microfluidic device have a particle size of 100 - 500 μm.

8. The preparation method of an inorganic light ceramic microsphere material according to claim 6, characterized in that, The addition ratio of the acrylamide to the matrix ceramic particles is (1 - 1.5):(50 - 55).

9. The preparation method of an inorganic light ceramic microsphere material according to claim 6, characterized in that, The programmatic temperature rise and low-temperature sintering include the following steps: First, raise the temperature to 400 °C at a rate of 5 °C / min for degreasing treatment, and then raise the temperature to 1400 °C at a rate of 10 °C / min for sintering, and adjust the argon flow rate to 50 mL / min.

10. Application of an inorganic lightweight ceramic microsphere material, characterized in that, Add the inorganic lightweight ceramic microsphere material prepared according to any one of claims 1 - 8 to the resin material as a reinforcing thermal insulation material.

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