Porous ceramic matrix, and preparation method therefor and use thereof

Abstract

The present application belongs to the technical field of electronic atomization materials, and specifically relates to a porous ceramic matrix, and a preparation method therefor and the use thereof. The porous ceramic matrix comprises a ceramic framework having a three-dimensional communicating pore structure, and the surface of the ceramic framework is provided with a coating layer, wherein the composition of the coating layer comprises at least one of zirconium oxide, magnesium oxide, and chromium oxide. Compared with a conventional porous ceramic matrix, the porous ceramic matrix provided in the present application presents a "core-shell" structure on the microscopic level, wherein the ceramic framework plays a role in strength supporting and construction of three-dimensional communicating pores; and the coating layers are uniformly distributed on the surface of the ceramic framework, and has the effect of modifying the ceramic framework, thereby achieving the adjustment of the performance of a substrate, the balance between the pore structure (porosity and pore size) and the strength, and the coordination between the thermal conductivity and the thermal expansion coefficient, and improving the bonding between the porous ceramic matrix and a heating film.

Description

A porous ceramic matrix, its preparation method and application

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410955997.X, filed on July 16, 2024, entitled "A porous ceramic matrix and its preparation method and application", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of electronic atomization materials technology, specifically relating to a porous ceramic matrix, its preparation method, and its application. Background Technology

[0004] Currently, the atomizing cores used in electronic atomization technology generally employ a method of heating and atomizing by covering the surface of a porous ceramic substrate with a metal heating film. The porous ceramic substrate is mainly composed of oxide ceramics, clay, and glass, and is made from micron-sized powder raw materials.

[0005] Porous ceramic matrices with high porosity (≥60%) often suffer from low strength, fragility, poor bonding strength with the heating film, and easy detachment. Existing technologies typically address these issues by optimizing the porous ceramic matrix material to achieve a better match between it and the heating film. This primarily involves matching the strength of the porous ceramic matrix and the heating film themselves, as well as properties such as the coefficient of thermal expansion (CTE) and thermal conductivity. However, due to material and process limitations, conventional atomizing cores often cannot simultaneously achieve a good match of these properties.

[0006] For example, most liquid atomizing media require porous ceramic matrices with high porosity, large pore size, low thermal conductivity, and high CTE. However, limitations in material selection and pore structure (porosity, pore size) result in lower strength of the porous ceramic matrix and poor bonding strength between the matrix and the heating film, leading to poor atomizing core durability. Conversely, some special media require porous ceramic matrices with both high thermal conductivity and high CTE, which conventional inorganic non-metallic matrices cannot simultaneously meet. Summary of the Invention

[0007] Therefore, the technical problem to be solved by this application is to overcome the defect that the porous ceramic matrix in the prior art cannot simultaneously satisfy the above-mentioned properties such as pore structure, strength, thermal conductivity, coefficient of thermal expansion and bonding between the matrix and the heating film, so as to provide a porous ceramic matrix, its preparation method and application.

[0008] Therefore, this application provides the following technical solution:

[0009] In a first aspect, this application provides a porous ceramic matrix, including a ceramic skeleton with a three-dimensional interconnected pore structure, wherein a coating layer is disposed on the surface of the ceramic skeleton, and the coating layer comprises at least one of zirconium oxide, magnesium oxide, and chromium oxide.

[0010] In some alternative embodiments, the porous ceramic matrix has a porosity of 40%-70% and an average pore size of 10μm-60μm.

[0011] In some alternative embodiments, the thickness of the coating layer is 5-30 μm;

[0012] And / or, the ceramic skeleton is composed of at least one of alumina, silicon dioxide, silicon carbide, and clay.

[0013] Secondly, this application provides a method for preparing the above-mentioned porous ceramic matrix, comprising the following steps:

[0014] S1, the coating material, dispersant and organic solvent are mixed to obtain a coating slurry, wherein the average particle size of the coating material is 100-500nm and accounts for 3%-20% of the volume of all powder raw materials, and the powder raw materials include the coating material, ceramic skeleton material, sintering aid and pore-forming agent;

[0015] S2, mix the ceramic skeleton material, sintering aid, pore-forming agent, binder and the above coating slurry, remove bubbles to obtain matrix slurry, wherein the average particle size of the ceramic skeleton material is 15μm-100μm, and accounts for 23%-45% of the volume of all powder raw materials.

[0016] S3, the obtained matrix slurry is shaped, layered, and isostatically pressed to obtain a ceramic green body;

[0017] S4, the ceramic green body is debonded and sintered to obtain the porous ceramic matrix.

[0018] In some alternative embodiments, the sintering aid has an average particle size range of 1 μm to 20 μm and accounts for 6% to 25% of the total volume of the powder raw materials.

[0019] And / or, the average particle size range of the pore-forming agent should be 5μm-100μm, accounting for 45%-68% of the total volume of the powder raw materials;

[0020] And / or, the amount of the dispersant is 0.5%-1.0% of the total mass of the powder raw materials;

[0021] And / or, the amount of the organic solvent used is 30%-60% of the total mass of the powder raw materials;

[0022] And / or, the amount of the binder is 8%-20% of the total mass of the powder raw materials.

[0023] In some optional embodiments, the adhesive discharge temperature is 400-600℃, the adhesive discharge time is 30-50h, and the heating rate is 1-2℃ / min;

[0024] And / or, the sintering temperature is 900℃-1300℃, the sintering time is 0.5-2h, and the heating rate is 3-6℃ / min;

[0025] And / or, the isostatic pressure is 10-40 MPa, the temperature is 60-85°C, and the time is not less than 5 min, optionally, the time is 5 min-30 min;

[0026] And / or, the molding method includes at least one of casting molding, injection molding, and dry pressing.

[0027] In some optional embodiments, the melting point or softening point of the sintering aid is below 900°C. Optionally, the sintering aid includes at least one of glass powder, MnO2, and V2O5.

[0028] And / or, the pore-forming agent includes at least one of polymethyl methacrylate, polystyrene, polyethylene terephthalate, and starch;

[0029] And / or, the organic solvent includes at least one selected from ethanol, ethyl acetate, butyl acetate, terpineol, methanol, and toluene;

[0030] And / or, the dispersant includes at least one of polyethylene glycol, triethanolamine, and BYK-111;

[0031] And / or, the adhesive is a polymeric adhesive, and optionally, the adhesive includes at least one of polyvinyl butyral (PVB) and polymethyl methacrylate (PMMA).

[0032] Thirdly, this application also provides an atomizing core, comprising the above-described porous ceramic substrate or the porous ceramic substrate prepared by the above-described preparation method.

[0033] Fourthly, this application also provides an atomizing device, including the aforementioned atomizing core.

[0034] Fifthly, this application also provides an aerosol generating device, including the aforementioned atomizing device.

[0035] The structures and compositions of the atomizing core, atomizing device, and aerosol generating equipment provided in this application are all conventional in the field, and this application does not impose specific limitations. Typically, and not specifically, a metal heating film can be coated onto the surface of the porous ceramic substrate provided above by means of screen printing or other methods to prepare a ceramic atomizing core for application in the field of electronic atomizing devices.

[0036] The technical solution of this application has the following advantages:

[0037] The porous ceramic matrix provided in this application includes a ceramic skeleton with a three-dimensional interconnected pore structure. A coating layer is disposed on the surface of the ceramic skeleton, wherein the coating layer comprises at least one of zirconium oxide, magnesium oxide, and chromium oxide. Compared with conventional porous ceramic matrices, the porous ceramic matrix provided in this application exhibits a core-shell structure. The ceramic skeleton provides strength support and constructs the three-dimensional interconnected pores, while the coating layer is uniformly distributed on the surface of the ceramic skeleton, modifying the ceramic skeleton. This allows for the adjustment of the substrate properties, achieving a balance between pore structure (porosity, pore size) and strength, as well as coordination of thermal conductivity and coefficient of thermal expansion, thereby improving the bonding between the porous ceramic matrix and the heating film.

[0038] The method for preparing a porous ceramic matrix provided in this application includes the following steps: S1, mixing a coating material, a dispersant, and an organic solvent to obtain a coating slurry, wherein the average particle size of the coating material is 100-500 nm and the volume percentage is 3%-20%; S2, mixing a ceramic skeleton material, a sintering aid, a pore-forming agent, and a binder with the above coating slurry, and removing bubbles to obtain a matrix slurry, wherein the particle size of the ceramic skeleton material is 15 μm-100 μm and the volume percentage is 23%-45%; S3, molding, stacking, and isostatically pressing the obtained matrix slurry to obtain a ceramic green body; S4, removing the binder from the ceramic green body and sintering to obtain the porous ceramic matrix. The preparation method provided in this application first mixes the coating material, dispersant, and organic solvent to avoid uneven composition caused by agglomeration of the coating material powder. Then, it mixes with the ceramic framework material, sintering aid, and pore-forming agent. By limiting the particle size of the coating material and the ceramic framework material, the final coating structure can be guaranteed. The coating mechanism includes: nano-sized coating material powder can be adsorbed onto the surface of coarse-particle ceramic framework powder; due to the blocking and extrusion effect of the pore-forming agent, the ceramic framework material and the coating layer are tightly bonded, and the coated powder does not form large-area aggregates. ， The thoroughly mixed slurry is molded to form a ceramic green strip, and the green strip is stacked and isostatically pressed according to the required thickness to finally form a ceramic green body; finally, the binder is removed and sintered to obtain a porous ceramic matrix with a coating layer. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0040] Figure 1 is a schematic diagram of the microstructure of the porous ceramic matrix provided in this application;

[0041] Figure 2 is an SEM image of the porous ceramic matrix provided in Embodiment 1 of this application;

[0042] Figure 3 is an SEM image of the porous ceramic matrix provided in Comparative Example 1 of this application;

[0043] Figure 4 is an SEM image of the porous ceramic matrix provided in Comparative Example 2 of this application.

[0044] Figure 5 is an SEM image of the porous ceramic matrix provided in Embodiment 6 of this application;

[0045] Reference numerals: 1. Ceramic skeleton; 2. Coating layer; 3. Pore structure. Detailed Implementation

[0046] The following embodiments are provided to better understand this application and are not limited to the preferred embodiments described herein. They do not constitute a limitation on the content and scope of protection of this application. Any product that is the same as or similar to this application, derived by anyone under the guidance of this application or by combining features of this application with other prior art, falls within the scope of protection of this application.

[0047] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0048] Example 1

[0049] This embodiment provides a porous ceramic matrix and a ceramic atomizing core. The microstructure of the porous ceramic matrix is ​​shown in Figure 1, which includes a ceramic skeleton 1 with a three-dimensional interconnected pore structure 3 and a coating layer 2 on the surface of the ceramic skeleton 1.

[0050] The specific preparation steps and operating parameters of the porous ceramic matrix and the ceramic atomizing core are as follows:

[0051] (1) Set the total volume of all powder raw materials required for the experiment (powder raw materials include coating materials, ceramic skeleton materials, sintering aids and pore-forming agents, the same below) to 100 parts. First, take 3 parts of nano (average particle size 500nm) ZrO2 powder in a planetary ball mill jar, and then add triethanolamine as a dispersant, ethyl acetate and ethanol as solvents respectively. The amount of dispersant accounts for 0.5% of the total mass of powder raw materials, the amount of ethyl acetate accounts for 20% of the total mass of powder raw materials, and the amount of ethanol accounts for 10% of the total mass of powder raw materials. Ball mill and disperse for 2 hours.

[0052] (2) After the ZrO2 powder is fully dispersed, add 23 parts by volume of Al2O3 powder (average particle size 15μm) to the slurry as the ceramic skeleton component; add 6 parts by volume of glass powder (average particle size 5μm) as a sintering aid; and 68 parts by volume of solvent-resistant polystyrene spherical powder (average particle size 50μm) as a pore-forming agent, and ball mill and mix for 1 hour.

[0053] (3) Add 10% PVB adhesive (as a molding binder) to the above-mixed slurry and continue ball milling for 3 hours.

[0054] (4) The above-mixed slurry is subjected to vacuum degassing treatment and then cast into a ceramic strip.

[0055] (5) Take 10 layers of the ceramic green tape with a thickness of 200μm after the above casting and stack them together. Then, perform isostatic pressing at 65℃ and 20MPa for 10 minutes to form a ceramic green body.

[0056] (6) The above ceramic green body is placed in a muffle furnace and heated to 600°C at a heating rate of 1°C / min to remove the glue and keep it at the temperature for 40 hours to remove the PVB glue and the pre-added pore-forming agent in the green body.

[0057] (7) After the ceramic green body is debinded, the temperature is raised to 1100℃ at a rate of 3℃ / min and held for 1h for sintering to prepare a porous ceramic matrix. Figure 2 is its electron microscope image. It can be seen from the figure that the dark phase is the porous ceramic skeleton, while the lighter-colored part surrounding the skeleton is the coating layer, forming a "core-shell" structure.

[0058] (8) A heating film paste is screen-printed on the surface of the porous ceramic substrate formed by the above sintering and heat-treated at 900°C to finally prepare a metal ruthenium film with a thickness of 30μm and a width of 70μm to form a ceramic atomizing core.

[0059] Example 2

[0060] This embodiment provides a porous ceramic matrix and a ceramic atomizing core. The microstructure of the porous ceramic matrix is ​​shown in Figure 1, which includes a ceramic skeleton 1 with a three-dimensional interconnected pore structure 3 and a coating layer 2 on the surface of the ceramic skeleton 1.

[0061] The specific preparation steps and operating parameters of the porous ceramic matrix and the ceramic atomizing core are as follows:

[0062] (1) Set the total volume of all powder raw materials required for the experiment to 100 parts. First, take 4 parts of nano (average particle size 500nm) ZrO2 powder in a planetary ball mill jar, and then add the dispersant triethanolamine, ethyl acetate and ethanol solvent respectively. The amount of dispersant accounts for 0.8% of the total mass of all powder raw materials, the amount of ethyl acetate accounts for 20% of the total mass of all powder raw materials, and the amount of ethanol accounts for 20% of the total mass of all powder raw materials. Ball mill and disperse for 2 hours.

[0063] (2) After the ZrO2 powder is fully dispersed, add 45 parts by volume of Al2O3 powder (average particle size 30μm) to the slurry as the ceramic skeleton component; add 6 parts by volume of glass powder (average particle size 5μm) as the sintering aid; and 45 parts by volume of solvent-resistant polystyrene spherical powder (average particle size 50μm) as the pore-forming agent, and ball mill and mix for 1 hour.

[0064] (3) Add 12% PVB adhesive by mass to the above-mixed slurry as a molding binder, and continue ball milling for 3 hours;

[0065] (4) The above-mixed slurry is subjected to vacuum degassing treatment and then cast into a ceramic strip.

[0066] (5) Take 10 layers of the ceramic green tape with a thickness of 200μm after the above casting and stack them together, and then perform isostatic pressing at 65℃ and 30MPa for 15min to form a ceramic green body.

[0067] (6) The above ceramic green body is placed in a muffle furnace and heated to 600°C at a rate of 1°C / min and held for 40 hours for debinding treatment to remove PVB glue and pre-added pore-forming agent from the green body.

[0068] (7) After the ceramic blank is debonded, the temperature is raised to 1150℃ at a rate of 3℃ / min and held for 2h for sintering, thereby preparing a porous ceramic matrix with a "core-shell" structure.

[0069] (8) A metal heating film is covered on the surface of the porous ceramic substrate formed by the above sintering through printing and sintering processes. The specific operation is the same as in Example 1, and a ceramic atomizing core is finally formed.

[0070] Example 3

[0071] This embodiment provides a porous ceramic matrix and a ceramic atomizing core. The microstructure of the porous ceramic matrix is ​​shown in Figure 1, which includes a ceramic skeleton 1 with a three-dimensional interconnected pore structure 3 and a coating layer 2 on the surface of the ceramic skeleton 1.

[0072] The specific preparation steps and operating parameters of the porous ceramic matrix and the ceramic atomizing core are as follows:

[0073] (1) Set the total volume of all powder raw materials required for the experiment to 100 parts. First, take 20 parts of nano (average particle size 500nm) ZrO2 powder in a planetary ball mill jar, and then add dispersant BYK111, ethyl acetate and ethanol solvent respectively. The amount of dispersant accounts for 0.5% of the total mass of all powder raw materials, the amount of ethyl acetate accounts for 20% of the total mass of all powder raw materials, and the amount of ethanol accounts for 20% of the total mass of all powder raw materials. Ball mill and disperse for 2 hours.

[0074] (2) After the ZrO2 powder is fully dispersed, add 23 parts by volume of Al2O3 powder (average particle size 30μm) to the slurry as the ceramic skeleton component; add 10 parts by volume of glass powder (average particle size 5μm) as a sintering aid; and 47 parts by volume of solvent-resistant polystyrene spherical powder (average particle size 40μm) as a pore-forming agent, and ball mill and mix for 1 hour;

[0075] (3) Add 10% PVB adhesive by mass to the above-mixed slurry as a molding binder, and continue ball milling for 3 hours;

[0076] (4) The above-mixed slurry is subjected to vacuum degassing treatment and then cast into a ceramic strip.

[0077] (5) Take 8 layers of the above-mentioned cast ceramic green tape with a thickness of 250μm, stack them together, and then perform isostatic pressing at 75℃ and 20MPa for 10min to form a ceramic green body;

[0078] (6) The above ceramic green body is placed in a muffle furnace and heated to 600°C at a rate of 1°C / min. It is kept at the temperature for 40 hours to remove the PVB glue and the pre-added pore-forming agent in the green body.

[0079] (7) After the ceramic blank is debonded, the temperature is raised to 1150℃ at a rate of 3℃ / min and held for 1h for sintering, thereby preparing a porous ceramic matrix with a "core-shell" structure.

[0080] (8) A metal heating film is covered on the surface of the porous ceramic substrate formed by the above sintering through printing and sintering processes. The specific operation is the same as in Example 1, and a ceramic atomizing core is finally formed.

[0081] Example 4

[0082] This embodiment provides a porous ceramic matrix and a ceramic atomizing core. The microstructure of the porous ceramic matrix is ​​shown in Figure 1, which includes a ceramic skeleton 1 with a three-dimensional interconnected pore structure 3 and a coating layer 2 on the surface of the ceramic skeleton 1.

[0083] The specific preparation steps and operating parameters of the porous ceramic matrix and the ceramic atomizing core are as follows:

[0084] (1) Set the total volume of all powder raw materials required for the experiment to 100 parts. First, take 3 parts of nano (average particle size 500nm) ZrO2 powder in a planetary ball mill jar, and then add dispersant BYK111, ethyl acetate and ethanol solvent respectively. The amount of dispersant accounts for 0.8% of the total mass of all powder raw materials, the amount of ethyl acetate accounts for 15% of the total mass of all powder raw materials, and the amount of ethanol accounts for 20% of the total mass of all powder raw materials. Ball mill and disperse for 2 hours.

[0085] (2) After the ZrO2 powder is fully dispersed, add 25 parts by volume of Al2O3 powder (average particle size 40μm) to the slurry as the ceramic skeleton component; add 10 parts by volume of glass powder (average particle size 5μm) as a sintering aid; and 62 parts by volume of solvent-resistant polystyrene spherical powder (average particle size 40μm) as a pore-forming agent, and ball mill and mix for 1 hour.

[0086] (3) Add 10% PVB adhesive by mass to the above-mixed slurry as a molding binder, and continue ball milling for 3 hours;

[0087] (4) The above-mixed slurry is subjected to vacuum degassing treatment and then cast into a ceramic strip.

[0088] (5) Take 8 layers of the above-mentioned cast ceramic green tape with a thickness of 250μm, stack them together, and then perform isostatic pressing at 75℃ and 20MPa for 5 minutes to form a ceramic green body.

[0089] (6) The above ceramic green body is placed in a muffle furnace and heated to 600°C at a rate of 1°C / min. It is kept at the temperature for 50 hours to remove the PVB glue and the pre-added pore-forming agent in the green body.

[0090] (7) After the ceramic blank is debonded, the temperature is raised to 1200℃ at a rate of 3℃ / min and held for 1h for sintering, thereby preparing a porous ceramic matrix with a "core-shell" structure.

[0091] (8) A metal heating film is covered on the surface of the porous ceramic substrate formed by the above sintering through printing and sintering processes. The specific operation is the same as in Example 1, and a ceramic atomizing core is finally formed.

[0092] Example 5

[0093] This embodiment provides a porous ceramic matrix and a ceramic atomizing core. The microstructure of the porous ceramic matrix is ​​shown in Figure 1, which includes a ceramic skeleton 1 with a three-dimensional interconnected pore structure 3 and a coating layer 2 on the surface of the ceramic skeleton 1.

[0094] The specific preparation steps and operating parameters of the porous ceramic matrix and the ceramic atomizing core are as follows:

[0095] (1) Set the total volume of all powder raw materials required for the experiment (powder raw materials include coating materials, ceramic skeleton materials, sintering aids and pore-forming agents, the same below) to 100 parts. First, take 4 parts of the volume of nano (average particle size 500nm) ZrO2 powder in a planetary ball mill jar, and then add triethanolamine as a dispersant, as well as ethyl acetate and ethanol solvent. The amount of dispersant accounts for 0.5% of the total mass of all powder raw materials, the amount of ethyl acetate accounts for 20% of the total mass of all powder raw materials, and the amount of ethanol accounts for 10% of the total mass of all powder raw materials. Ball mill and disperse for 2 hours.

[0096] (2) After the ZrO2 powder is fully dispersed, add 24 parts by volume of Al2O3 powder (average particle size 100μm) to the slurry as the ceramic skeleton component; add 25 parts by volume of glass powder (average particle size 20μm) as a sintering aid; and 47 parts by volume of solvent-resistant polystyrene spherical powder (average particle size 100μm) as a pore-forming agent, and ball mill and mix for 1 hour.

[0097] Steps (3) to (8) are the same as in Example 1.

[0098] Example 6

[0099] This embodiment provides a porous ceramic matrix and a ceramic atomizing core. The microstructure of the porous ceramic matrix is ​​shown in Figure 1, which includes a ceramic skeleton 1 with a three-dimensional interconnected pore structure 3 and a coating layer 2 on the surface of the ceramic skeleton 1.

[0100] The specific preparation steps and operating parameters of the porous ceramic matrix and the ceramic atomizing core are as follows:

[0101] (1) Set the total volume of all powder raw materials required for the experiment to 100 parts. First, take 4 parts of nano (average particle size 300nm) MgO powder in a planetary ball mill jar. Then, add triethanolamine as a dispersant, as well as ethyl acetate and butyl acetate solvents. The amount of dispersant accounts for 0.8% of the total mass of all powder raw materials, the amount of ethyl acetate accounts for 20% of the total mass of all powder raw materials, and the amount of ethanol accounts for 20% of the total mass of all powder raw materials. Ball mill and disperse for 2 hours.

[0102] (2) After the MgO powder is fully dispersed, add 45 parts by volume of SiC powder (average particle size 30μm) to the slurry as the ceramic skeleton component; add 6 parts by volume of MnO2 (average particle size 5μm) as the sintering aid; and 45 parts by volume of starch powder (average particle size 50μm) as the pore-forming agent, and ball mill and mix for 1 hour.

[0103] (3) Add 12% PMMA adhesive by mass to the above-mixed slurry as a molding binder, and continue ball milling for 3 hours;

[0104] Steps (4) to (8) are the same as in Example 1. The SEM image of the obtained porous ceramic substrate is shown in Figure 5. It can be seen from the figure that a clear coating layer has been formed.

[0105] Comparative Example 1

[0106] This comparative example provides a porous ceramic matrix and a ceramic atomizing core. The specific preparation steps and operating parameters are as follows:

[0107] (1) Set the total volume of all powder raw materials required for the experiment to 100 parts. First, take 24 parts of Al2O3 powder (average particle size 30μm) as the ceramic skeleton component; then add 8 parts of glass powder (average particle size 5μm) as sintering aid; and 68 parts of polystyrene spherical powder (average particle size 40μm) as pore-forming agent. Then add the dispersant triethanolamine, ethyl acetate and ethanol solvent respectively. The amount of dispersant accounts for 0.5% of the total mass of all powder raw materials, the amount of ethyl acetate accounts for 20% of the total mass of all powder raw materials, and the amount of ethanol accounts for 20% of the total mass of all powder raw materials. Ball mill and disperse for 2 hours.

[0108] The subsequent steps are the same as steps (3) to (8) in Example 1; Figure 3 is an electron microscope image of the obtained porous ceramic matrix. It can be seen from the figure that only one color phase can be observed, namely the porous ceramic skeleton, and no coating layer is observed.

[0109] Comparative Example 2

[0110] This comparative example provides a porous ceramic matrix, and the specific preparation steps and operating parameters are as follows:

[0111] (1) Set the total volume of all powder raw materials required for the experiment to 100 parts. First, take 10 parts of nano (average particle size 500nm) ZrO2 powder in a planetary ball mill jar, and then add dispersant BYK111, ethyl acetate and ethanol solvent respectively. The amount of dispersant accounts for 20% of the mass of all powder raw materials, the amount of ethyl acetate accounts for 20% of the mass of all powder raw materials, and the amount of ethanol accounts for 20% of the mass of all powder raw materials. Ball mill and disperse for 2 hours.

[0112] (2) After the ZrO2 powder is fully dispersed, add 40 parts by volume of Al2O3 powder (average particle size 30μm) to the slurry as the ceramic skeleton component; add 30 parts by volume of glass powder (average particle size 5μm) as the sintering aid; and 20 parts by volume of solvent-resistant polystyrene spherical powder (average particle size 20μm) as the pore-forming agent, and ball mill and mix for 1 hour;

[0113] The subsequent steps are the same as steps (3) to (7) in Example 4; Figure 4 is an electron microscope image of the obtained porous ceramic substrate. It can be seen from the figure that the substrate prepared according to the above process is almost sintered and dense due to the low content of pore-forming agent, the small particle size of pore-forming agent, and the high glass content, etc., and does not form the expected porous structure. Therefore, it cannot be used as an atomizer and no metal heating film is covered on its surface.

[0114] Comparative Example 3

[0115] This comparative example provides a porous ceramic matrix and a ceramic atomizing core. The only difference from Example 1 is that in step (1), an equal volume of SiO2 powder (average particle size of 500 nm) is used instead of ZrO2 powder.

[0116] Test case

[0117] The physical performance parameters of the porous ceramic substrate and atomizing core provided in each embodiment and comparative example were tested. The specific test methods are as follows:

[0118] Coating thickness: The cross-section of the broken porous ceramic was observed under a scanning electron microscope at 500x magnification. The thickness of the coating at different locations was measured, with no fewer than 15 test points, and the average value was taken.

[0119] Porosity: Referring to GB / T 32361-2015, after fully immersing the sample in water, weigh its mass in air and water respectively, calculate the volume according to Archibald's law, and calculate the porosity by dividing the mass difference between air and water by the volume.

[0120] Average pore size: Referencing GB / T 32361-2015, the average pore size of porous ceramics was tested using the bubble point method;

[0121] Bending strength: Referring to GB / T 13465.2-2014, the three-point bending strength of the sample was tested using a mechanical testing machine;

[0122] Coefficient of thermal expansion: The linear thermal expansion coefficient of the sample was tested using the push rod method, referring to GB / T 16535-2008.

[0123] Thermal conductivity: Referring to GB / T 39862-2021, the thermal conductivity is calculated by testing the specific heat capacity and thermal diffusivity of the sample.

[0124] Bonding strength between porous ceramic substrate and metal heating film: Under microscopic observation, an automatic push-pull force testing machine was used to apply shear force to the heating film, specifying the shear height and shear rate. The maximum force value at which the heating film breaks or detaches was recorded, which is the test value of the film-substrate bonding strength. Specific test results are shown in the table below:

[0125] Table 1

[0126] The data in the table above show that, due to the lack of a coating layer in Comparative Example 1, the modification effect on the skeleton was not achieved, resulting in relatively low flexural strength and coefficient of thermal expansion. The final film-substrate adhesion was also significantly worse than that of the examples with coating layers. In Comparative Example 3, due to the relatively low coefficient of thermal expansion and thermal conductivity of SiO2 material itself, even though the final porous ceramic had high strength, its film-substrate adhesion was significantly reduced. This indicates that the inappropriate selection of the coating layer material led to poor experimental results.

[0127] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A porous ceramic matrix, characterized by, The ceramic framework with a three-dimensional interconnected pore structure, and a surface of the ceramic framework is provided with a cladding layer, wherein a composition of the cladding layer comprises at least one of zirconium oxide, magnesium oxide and chromium oxide.

2. The porous ceramic matrix according to claim 1, characterized in that The porosity of the porous ceramic matrix is 40%-70%, and the average pore size is 10-60 μm.

3. The porous ceramic matrix according to claim 1 or 2, characterized in that The thickness of the cladding layer is 5-30 μm. And / or, the composition of the ceramic framework comprises at least one of alumina, silica, silicon carbide and clay.

4. A method for producing the porous ceramic matrix according to any one of claims 1 to 3, characterized in that The method comprises the following steps: S1, mixing a cladding material, a dispersant and an organic solvent to obtain a cladding slurry, wherein the average particle size of the cladding material is 100-500 nm, and the volume ratio of the cladding material to all powder raw materials is 3%-20%, and the powder raw materials comprise the cladding material, a ceramic framework material, a sintering aid and a pore-forming agent; S2, mixing the ceramic framework material, the sintering aid, the pore-forming agent, a binder and the above-mentioned cladding slurry, and removing bubbles to obtain a matrix slurry, wherein the average particle size of the ceramic framework material is 15-100 μm, and the volume ratio of the ceramic framework material to all powder raw materials is 23%-45%; S3, forming and laminating the obtained matrix slurry, and isostatic pressing to obtain a ceramic green body; S4, degassing and sintering the ceramic green body to obtain the porous ceramic matrix.

5. The method of producing a porous ceramic matrix according to claim 4, characterized by, The average particle size of the sintering aid is 1-20 μm, and the volume ratio of the sintering aid to all powder raw materials is 6%-25%; And / or, the average particle size of the pore-forming agent is 5-100 μm, and the volume ratio of the pore-forming agent to all powder raw materials is 45%-68%; And / or, the amount of the dispersant is 0.5%-1.0% of the mass of all powder raw materials; And / or, the amount of the organic solvent is 30%-60% of the mass of all powder raw materials; And / or, the amount of the binder is 8%-20% of the mass of all powder raw materials.

6. The method for producing a porous ceramic matrix according to claim 4 or 5, characterized in that, The temperature of the degassing is 400-600 ℃, the degassing time is 30-50 h, and the heating rate is 1-2 ℃ / min; And / or, the sintering temperature is 900-1300 ℃, the sintering time is 0.5-2 h, and the heating rate is 3-6 ℃ / min; And / or, the isostatic pressing pressure is 10-40 MPa, the temperature is 60-85 ℃, and the time is not less than 5 min, and optionally, the time is 5-30 min; And / or, the forming mode comprises at least one of flow casting, injection molding and dry pressing.

7. The method of producing a porous ceramic matrix according to claim 6, characterized in that, The melting point or softening point of the sintering aid is below 900 ℃, and optionally, the sintering aid comprises at least one of glass powder, MnO2 and V2O5; And / or, the pore-forming agent comprises at least one of polymethyl methacrylate, polystyrene, polyethylene terephthalate and starch; And / or, the organic solvent comprises at least one of ethanol, ethyl acetate, butyl acetate, terpineol, methanol and toluene; And / or, the dispersant comprises at least one of polyethylene glycol, triethanolamine and BYK-111. And / or, the adhesive is a high molecular adhesive, optionally, the adhesive comprises at least one of polyvinyl butyral PVB, polymethyl methacrylate PMMA.

8. An atomizing core characterized by, The porous ceramic substrate according to any one of claims 1-3 or prepared by the method according to any one of claims 4-7.

9. An atomising device characterised in that, The atomizing core according to claim 8.

10. An aerosol-generating device comprising, The atomizing device according to claim 9.

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