Porous ceramic, preparation method thereof and atomizing core

Abstract

The invention belongs to the technical field of porous ceramic forming, and relates to porous ceramic, a preparation method thereof and an atomizing core. The preparation method of the porous ceramic comprises the following steps: uniformly mixing magnesium oxide, aluminum hydroxide, silicon dioxide aerogel, graphite powder, glass powder and boric oxide to obtain mixed powder; uniformly mixing the mixed powder with a dispersing agent, a plasticizer, a binder and deionized water to obtain slurry; forming the slurry into a ceramic green body by adopting a tape casting method; the ceramic green body is dried, degummed and sintered, and the porous ceramic is obtained. The porous ceramic prepared by the invention is flat in surface, uniform in pore size distribution and beneficial to taste reduction; the characteristics of relatively high breaking strength, low thermal expansion coefficient and low thermal conductivity are realized; in addition, the through hole ratio and the porosity are effectively improved.

Description

Technical Field

[0001] This application relates to the field of porous ceramic forming technology, and more specifically, to a porous ceramic and its preparation method, as well as an atomizing core. Background Technology

[0002] Currently, most porous ceramics are formed using injection molding. However, injection molding has a sprue, which leads to uneven density in the green body, resulting in uneven pore size distribution after sintering. Furthermore, the high stress within the injection-molded green body can cause deformation of the sintered product, ultimately leading to poor consistency in mass production and a low product qualification rate. Secondly, the injection sprue causes raw material waste. Thirdly, most porous ceramics use organic pore-forming agents to create pores, which are prone to decomposition and release toxic decomposition products during the glue removal process. Summary of the Invention

[0003] This application provides a porous ceramic and its preparation method, as well as an atomizing core, to solve the problems of uneven pore size distribution, poor consistency, and low porosity in porous ceramics prepared in the prior art.

[0004] To address the aforementioned technical problems, this application provides a method for preparing porous ceramics, employing the following technical solution:

[0005] A method for preparing porous ceramics includes the following steps:

[0006] Magnesium oxide, aluminum hydroxide, silica aerogel, graphite powder, glass powder, and boron oxide are mixed evenly to obtain a mixed powder.

[0007] The mixed powder is mixed evenly with dispersant, plasticizer, binder and deionized water to obtain slurry;

[0008] The slurry is formed into a ceramic green body using a casting method;

[0009] The ceramic green body is dried, debinded, and sintered to obtain porous ceramic.

[0010] Further, in the slurry, by mass percentage, the graphite powder is 13-50 wt%, the silica aerogel is 20-25 wt%, the magnesium oxide is 6-9 wt%, the aluminum hydroxide is 6-9 wt%, the boron oxide is 3-4 wt%, the glass powder is 3-7 wt%, the dispersant is 1-2 wt%, the binder is 1-3 wt%, the plasticizer is 2-3 wt%, and the deionized water is 8-25 wt%.

[0011] Furthermore, the graphite powder is spherical graphite with a diameter of 100-200 μm and an impurity content of <1%;

[0012] The magnesium oxide, aluminum hydroxide, silica aerogel, glass powder, and boron oxide are spherical particles with diameters of 50–150 μm and purity >99%.

[0013] Furthermore, the dispersant is one of ammonium polyacrylate and polyethylene glycol octylphenyl ether;

[0014] The binder is water glass, sodium carboxymethyl cellulose, PVA, etc. One or a combination of B-76 Polyvinyl butyral (PVB);

[0015] The plasticizer is one of dibutyl phthalate and polyethylene glycol.

[0016] Furthermore, the step of uniformly mixing the mixed powder with the dispersant, plasticizer, binder, and water to obtain a slurry specifically includes: placing the mixed powder, dispersant, plasticizer, binder, and water in a mixing container and vacuum stirring for 15 to 30 minutes.

[0017] Furthermore, in the step of forming the slurry into a ceramic green body using the casting method, the thickness of the ceramic green body is 0.2–1.0 mm;

[0018] After the step of forming the slurry into a ceramic green body, the method further includes: stacking multiple layers of the ceramic green body and applying pressure in the thickness direction, with a pressure of 10-35 MPa and a pressure time of 5-10 min.

[0019] Furthermore, the steps of drying, debinding, and sintering the ceramic green body to obtain porous ceramics specifically include: heating the ceramic green body in an oxidizing atmosphere furnace at a heating rate of 0.5–1.5 °C / min, holding it at 400–500 °C for 2–4 hours to debind it, and after debinding, heating it at a heating rate of 5–8 °C / min to 900–1100 °C for 2–3 hours to sinter it, and then cooling it to room temperature with the furnace to obtain porous ceramics.

[0020] To address the aforementioned technical problems, this application also provides a porous ceramic, employing the technical solution described below:

[0021] A porous ceramic is prepared using the porous ceramic preparation method described above.

[0022] Furthermore, the porous ceramic has a porosity of 65-90%, an average pore diameter of 25-90 μm, and a flexural strength of 10-35 MPa.

[0023] To address the aforementioned technical problems, this application also provides an atomizing core, which employs the following technical solution:

[0024] An atomizing core includes a porous ceramic as described above, wherein a heating layer is provided on the porous ceramic.

[0025] Compared with the prior art, the embodiments of this application have the following advantages: In this embodiment, the patent uses a water-based casting method to form ceramic green bodies, which reduces the amount of organic solvents used and is environmentally friendly and safe. Secondly, the casting method has low internal stress, uniform distribution of powder particles in the slurry, and a smooth surface and uniform pore size distribution after sintering, which can improve the consistency of mass production. After thick film printing or thin film coating of the heating layer on the obtained porous ceramic, the heating layer can be well combined with the porous ceramic, reducing defects and increasing lifespan, which is beneficial to the reproduction of taste.

[0026] In this embodiment, boron oxide and glass powder mainly serve as sintering aids to lower the sintering temperature of magnesium aluminum spinel. Magnesium oxide and aluminum hydroxide, under the action of the sintering aids, form magnesium aluminum spinel with an octahedral crystal structure in the silica aerogel matrix. During the sintering process, magnesium aluminum spinel crystals with an octahedral crystal structure are dispersed in the silica aerogel matrix, ultimately producing a porous ceramic with a magnesium aluminum spinel structure mixed with silica aerogel. The crystal structure of this crystal determines that the resulting porous ceramic has high flexural strength and low coefficient of thermal expansion. At the same time, since the nanopores and three-dimensional network structure of silica aerogel disrupt the heat conduction path, the resulting porous ceramic has low thermal conductivity. After setting a heating layer on the porous ceramic, the heat can be concentrated in the heating layer during the atomization of e-liquid, thereby improving atomization efficiency, resulting in a more complete flavor explosion while lower power consumption.

[0027] In addition, traditional organic pore-forming agents are prone to producing toxic decomposition products during the debinding process, and the debinding process is also long and costly. This application shortens the debinding process by adding an inorganic pore-forming agent: graphite powder. The decomposition product of graphite powder is carbon dioxide, which is both economical and environmentally friendly, and effectively improves the through-pore ratio and porosity of the prepared porous ceramics. Attached Figure Description

[0028] To more clearly illustrate the solution of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart of an embodiment of the porous ceramic preparation method according to this application. Detailed Implementation

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0031] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0033] This application provides a method for preparing porous ceramics, such as... Figure 1 As shown, the method includes the following steps:

[0034] S1. Mix magnesium oxide, aluminum hydroxide, silica aerogel, graphite powder, glass powder, and boron oxide evenly to obtain a mixed powder.

[0035] S2. Mix the mixed powder with dispersant, plasticizer, binder and deionized water evenly to obtain a slurry;

[0036] S3. The slurry is formed into a ceramic green body using a casting method;

[0037] S4. The ceramic green body is dried, debinded, and sintered to obtain porous ceramic.

[0038] In this embodiment, the patent uses a water-based casting method to form ceramic green bodies, which reduces the amount of organic solvents used, making it environmentally friendly and safe. Secondly, the casting method has lower internal stress, and the powder particles in the slurry are evenly distributed. After sintering, the surface is smooth and the pore size distribution is uniform, which can improve the consistency of mass production. After thick film printing or thin film coating of the heating layer on the obtained porous ceramic, the heating layer can be well combined with the porous ceramic, reducing defects, increasing lifespan, and facilitating the reproduction of taste.

[0039] In this embodiment, boron oxide and glass powder mainly serve as sintering aids to lower the sintering temperature of magnesium aluminum spinel. Magnesium oxide and aluminum hydroxide, under the action of the sintering aids, form magnesium aluminum spinel with an octahedral crystal structure in the silica aerogel matrix. During the sintering process, magnesium aluminum spinel crystals with an octahedral crystal structure are dispersed in the silica aerogel matrix, ultimately producing a porous ceramic with a magnesium aluminum spinel structure mixed with silica aerogel. The crystal structure of this crystal determines that the resulting porous ceramic has high flexural strength and low coefficient of thermal expansion. At the same time, since the nanopores and three-dimensional network structure of silica aerogel disrupt the heat conduction path, the resulting porous ceramic has low thermal conductivity. After setting a heating layer on the porous ceramic, the heat can be concentrated in the heating layer during the atomization of e-liquid, thereby improving atomization efficiency, resulting in a more complete flavor explosion while lower power consumption.

[0040] In addition, traditional organic pore-forming agents are prone to producing toxic decomposition products during the debinding process, and the debinding process is also long and costly. This application shortens the debinding process by adding an inorganic pore-forming agent: graphite powder. The decomposition product of graphite powder is carbon dioxide, which is both economical and environmentally friendly, and effectively improves the through-pore ratio and porosity of the prepared porous ceramics.

[0041] Further, in the slurry, by mass percentage, the graphite powder is 13-50 wt%, the silica aerogel is 20-25 wt%, the magnesium oxide is 6-9 wt%, the aluminum hydroxide is 6-9 wt%, the boron oxide is 3-4 wt%, the glass powder is 3-7 wt%, the dispersant is 1-2 wt%, the binder is 1-3 wt%, the plasticizer is 2-3 wt%, and the deionized water is 8-25 wt%.

[0042] Optionally, the mass percentage of graphite powder can be any value or a range formed by any two of the following: 13%, 15%, 18%, 20%, 23%, 25%, 28%, 30%, 33%, 35%, 38%, 40%, 43%, 45%, 48%, 50%.

[0043] Optionally, the mass percentage of silica aerogel can be any value or a range formed by any two of the following: 20%, 20.5%, 21%, 21.5%, 22%, 22.5%, 23%, 23.5%, 24%, 24.5%, 25%.

[0044] Optionally, the mass percentage of magnesium oxide can be any value or a range formed by any two of the following: 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%.

[0045] Optionally, the mass percentage of aluminum hydroxide can be any value or a range formed by any two of the following: 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%.

[0046] Optionally, the mass percentage of boron oxide can be any value or a range formed by any two of the following: 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4%.

[0047] Optionally, the mass percentage of glass powder can be any value or a range formed by any two of the following: 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%.

[0048] Optionally, the mass percentage of the dispersant can be any value or a range formed by any two of the following: 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%.

[0049] Optionally, the mass percentage of the adhesive can be any value or a range formed by any two of the following: 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%.

[0050] Optionally, the mass percentage of the plasticizer can be any value or a range formed by any two of the following: 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, and 3%.

[0051] Optionally, the mass percentage of deionized water can be any value or a range formed by any two of the following: 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%.

[0052] Furthermore, the graphite powder is spherical graphite with a diameter of 100-200 μm and an impurity content of <1%.

[0053] In this embodiment, the graphite powder is spherical graphite with a diameter between 100 and 200 μm. This avoids the graphite powder having a large diameter distribution, thereby reducing the uneven distribution of pore size and the phenomenon of more closed pores and fewer open pores, thus improving porosity.

[0054] In this embodiment, the impurity content of the graphite powder is <1% to avoid the generation of toxic decomposition products during the glue removal process.

[0055] Optionally, the diameter of the graphite powder can be any value or a range formed by any two of the following: 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, and 200μm.

[0056] Furthermore, the magnesium oxide, aluminum hydroxide, silica aerogel, glass powder, and boron oxide are spherical particles with diameters of 50–150 μm and purity >99%.

[0057] In this embodiment, magnesium oxide, aluminum hydroxide, silica aerogel, glass powder, and boron oxide are all spherical particles with diameters of 50–150 μm, which reduces the diameter distribution range of each component and facilitates uniform mixing of each component.

[0058] In this embodiment, the purity of magnesium oxide, aluminum hydroxide, silica aerogel, glass powder, and boron oxide is >99%, which reduces the impact of impurities during sintering.

[0059] Optionally, the diameters of magnesium oxide, aluminum hydroxide, silica aerogel, glass powder, and boron oxide can be any value or a range formed by any two of the following: 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, and 150 μm.

[0060] Furthermore, the dispersant is one of ammonium polyacrylate and polyethylene glycol octylphenyl ether.

[0061] In this embodiment, the dispersant selected from the above materials can improve the stability of the slurry, prevent particle re-agglomeration, and thus increase the solid content of the slurry.

[0062] Furthermore, the binder is water glass, sodium carboxymethyl cellulose, PVA, One or a combination of B-76 Polyvinylbutyral (PVB).

[0063] In this embodiment, the binder selected from the above-mentioned materials can improve the flexural strength of the ceramic green body or prevent powder segregation.

[0064] Furthermore, the plasticizer is one of dibutyl phthalate (DBP) and polyethylene glycol (PEG).

[0065] In this embodiment, the plasticizer selected from the above materials can improve the overall plasticity of the ceramic green body, ensure that the ceramic green body has a certain strength, and maintain the original shape of the ceramic green body before firing.

[0066] Further, step S2, mixing the mixed powder with dispersant, plasticizer, binder and water to obtain a slurry, specifically includes: placing the mixed powder, dispersant, plasticizer, binder and water in a mixing container and vacuum stirring for 15 to 30 minutes.

[0067] In this embodiment, the components are placed in a stirring container and vacuum stirred, which can defoam and mix the components evenly.

[0068] Optionally, the vacuum stirring time can be any value or a range formed by any two of the following: 15 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, and 30 min.

[0069] Furthermore, in step S3, where the slurry is formed into a ceramic green body using a casting method, the thickness of the ceramic green body is 0.2–1.0 mm.

[0070] In this embodiment, the thickness of the ceramic green body can be set according to actual needs, and this application does not impose any restrictions on it.

[0071] Optionally, the thickness of the ceramic green body can be any value or a range formed by any two of the following: 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1 mm.

[0072] Furthermore, after step S3, which involves forming the slurry into a ceramic green body using a casting method, the method further includes: stacking multiple layers of the ceramic green body and applying pressure in the thickness direction, with a pressure of 10-35 MPa and a pressure time of 5-10 min.

[0073] In this embodiment, when the thickness of a single-layer ceramic green body does not meet the actual requirements, multiple layers of ceramic green bodies can be stacked and pressurized, and then the stacked multi-layer ceramic green bodies can be dried, debinded, and sintered to obtain porous ceramics of the required thickness.

[0074] Optionally, the pressure can be any value or a range formed by any two of the following: 10MPa, 12MPa, 14MPa, 16MPa, 18MPa, 20MPa, 22MPa, 24MPa, 26MPa, 28MPa, 30MPa, 32MPa, 34MPa, and 35MPa.

[0075] Optionally, the pressurization time can be any value or a range formed by any two of the following: 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, and 15 min.

[0076] Further, step S4, drying, debinding, and sintering the ceramic green body to obtain porous ceramic, specifically includes: slowly heating the ceramic green body in an oxidizing atmosphere furnace at a heating rate of 0.5-1.5℃ / min, holding it at 400-500℃ for 2-4 hours to debind it, and after debinding, heating it at a rate of 5-8℃ / min to 900-1100℃ for 2-3 hours to sinter it, and then cooling it to room temperature with the furnace to obtain porous ceramic.

[0077] In this embodiment, there are clear requirements for controlling the heating rate and the holding time at each stage, so as to achieve the purpose of crystal formation and decomposition of various components during the heating process, and finally obtain a porous ceramic atomizing core with high flexural strength, low thermal conductivity and good porosity.

[0078] This application also provides a porous ceramic, which is prepared by the porous ceramic preparation method described above.

[0079] In this embodiment, the patent uses a water-based casting method to form ceramic green bodies, which reduces the amount of organic solvents used, making it environmentally friendly and safe. Secondly, the casting method has lower internal stress, and the powder particles in the slurry are evenly distributed. After sintering, the surface is smooth and the pore size distribution is uniform, which can improve the consistency of mass production. After thick film printing or thin film coating of the heating layer on the obtained porous ceramic, the heating layer can be well combined with the porous ceramic, reducing defects, increasing lifespan, and facilitating the reproduction of taste.

[0080] In this embodiment, boron oxide and glass powder mainly serve as sintering aids to lower the sintering temperature of magnesium aluminum spinel. Magnesium oxide and aluminum hydroxide, under the action of the sintering aids, form magnesium aluminum spinel with an octahedral crystal structure in the silica aerogel matrix. During the sintering process, magnesium aluminum spinel crystals with an octahedral crystal structure are dispersed in the silica aerogel matrix, ultimately producing a porous ceramic with a magnesium aluminum spinel structure mixed with silica aerogel. The crystal structure of this crystal determines that the resulting porous ceramic has high flexural strength and low coefficient of thermal expansion. At the same time, since the nanopores and three-dimensional network structure of silica aerogel disrupt the heat conduction path, the resulting porous ceramic has low thermal conductivity. After setting a heating layer on the porous ceramic, the heat can be concentrated in the heating layer during the atomization of e-liquid, thereby improving atomization efficiency, resulting in a more complete flavor explosion while lower power consumption.

[0081] In addition, traditional organic pore-forming agents are prone to producing toxic decomposition products during the debinding process, and the debinding process is also long and costly. This application shortens the debinding process by adding an inorganic pore-forming agent: graphite powder. The decomposition product of graphite powder is carbon dioxide, which is both economical and environmentally friendly, and effectively improves the through-pore ratio and porosity of the prepared porous ceramics.

[0082] Furthermore, the porous ceramic has a porosity of 65-90%, an average pore diameter of 25-90 μm, and a flexural strength of 10-35 MPa.

[0083] Optionally, the porosity of the porous ceramic can be any value or a range formed by any two of the following: 65%, 68%, 70%, 73%, 75%, 78%, 80%, 83%, 85%, 88%, 90%.

[0084] Optionally, the average pore diameter of the pores in the porous ceramic can be any value or a range formed by any two of the following: 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, and 90μm.

[0085] Optionally, the flexural strength of the porous ceramic is any value or a range formed by any two of the following: 10MPa, 12MPa, 14MPa, 16MPa, 18MPa, 20MPa, 22MPa, 24MPa, 26MPa, 28MPa, 30MPa, 32MPa, 34MPa, and 35MPa.

[0086] The following specific embodiments will be used to illustrate the contents of this application in more detail and to further elaborate on this application, but these embodiments are by no means intended to limit this application.

[0087] This application embodiment also provides an atomizing core, the atomizing core comprising the porous ceramic as described above, wherein a heating layer is provided on the porous ceramic.

[0088] In this embodiment, the heating layer can be well integrated with the porous ceramic, reducing defects, increasing lifespan, and improving taste reproduction.

[0089] In this embodiment, the porous ceramic has a low thermal conductivity. After the heating layer is set on the porous ceramic, the heat can be concentrated in the heating layer during the process of atomizing the e-liquid, thereby improving the atomization efficiency, making the flavor more explosive and the power lower at the same time.

[0090] Example 1

[0091] The preparation method of the magnesium-aluminum spinel structured porous ceramic with mixed silica aerogel in this embodiment is as follows:

[0092] S1. 100μm graphite powder, 50μm MgO (magnesium oxide), 50μm Al(OH)3 (aluminum hydroxide), silica aerogel, boron oxide, and glass powder are mixed in a three-dimensional mixer to obtain a mixed powder.

[0093] S2. After adding dispersant, plasticizer, binder and deionized water to the mixed powder, vacuum stir in a mixing container for 30 minutes. After mixing evenly, a slurry is obtained. Among them, the dispersant is selected from ammonium polyacrylate, the plasticizer is selected from dibutyl phthalate, and the binder is selected from water glass.

[0094] In the slurry, by mass percentage, the following components are present: 25 wt% graphite powder, 25 wt% silica aerogel, 6 wt% MgO, 6 wt% Al(OH)3, 3 wt% boron oxide, 7 wt% glass powder, 2 wt% dispersant, 1 wt% binder, 2 wt% plasticizer, and 23 wt% deionized water.

[0095] S3. The slurry is cast on a casting machine to obtain a single-layer ceramic green body with a thickness of 0.5 mm. Six layers of ceramic green bodies are stacked and pressurized at 20 MPa for 10 min in the thickness direction to obtain a multi-layer ceramic green body with a thickness of 2.5-2.8 mm.

[0096] S4. The above-mentioned multilayer ceramic green body is slowly heated in an oxidizing atmosphere furnace at a heating rate of 1.0℃ / min, and held at 430℃ for 4h to remove the binder. After the binder is removed, the temperature is increased to 1000℃ at a heating rate of 6℃ / min and held for 4h for sintering. Then, it is cooled to room temperature with the furnace to obtain a porous ceramic with a zinc-aluminum spinel structure.

[0097] Example 2

[0098] The difference from Example 1 is that in step S2, the slurry contains, by mass percentage, 40 wt% graphite powder, 20 wt% silica aerogel, 6 wt% MgO, 6 wt% Al(OH)3, 3 wt% boron oxide, 7 wt% glass powder, 2 wt% dispersant, 1 wt% binder, 2 wt% plasticizer, and 13 wt% deionized water.

[0099] Example 3

[0100] The difference from Example 1 is that in step S2, the slurry contains, by mass percentage, 30 wt% graphite powder, 20 wt% silica aerogel, 6 wt% MgO, 6 wt% Al(OH)3, 3 wt% boron oxide, 7 wt% glass powder, 2 wt% dispersant, 1 wt% binder, 2 wt% plasticizer, and 23 wt% deionized water.

[0101] Comparative Example 1

[0102] The difference from Example 1 is that in step S2, the slurry contains, by mass percentage, 25 wt% graphite powder, 18.5 wt% MgO, 18.5 wt% Al(OH)3, 3 wt% boron oxide, 7 wt% glass powder, 2 wt% dispersant, 1 wt% binder, 2 wt% plasticizer, and 23 wt% deionized water.

[0103] Test Result Analysis:

[0104] The porous ceramics of Examples 1-3 and Comparative Example 1 were tested and analyzed, and the test results are shown in Table 1.

[0105] Table 1

[0106] Porosity Average through hole diameter Flexural strength thermal conductivity Example 1 73％ 63μm 22MPa 7.2*10^-4W / (m·k) Example 2 88％ 71μm 15MPa 5.9*10^-4W / (m·k) Example 3 72％ 45μm 29MPa 1.9*10^-4W / (m·k) Comparative Example 1 42％ 36μm 43MPa 5.9*10^-2W / (m·k)

[0107] As shown in Table 1, the porous ceramics prepared by the method of this application have a porosity of 65-90%, an average pore diameter of 25-90 μm, and a flexural strength of 10-35 MPa.

[0108] The porosity, average pore size, and thermal conductivity of Examples 1-3 are all superior to those of Comparative Example 1, indicating that boron oxide and glass powder mainly act as sintering aids to lower the sintering temperature of magnesium aluminum spinel. Magnesium oxide and aluminum hydroxide, under the action of the sintering aids, can form magnesium aluminum spinel with a regular octahedral crystal structure in the silica aerogel matrix. During the sintering process, magnesium aluminum spinel crystals with a regular octahedral crystal structure are dispersed in the silica aerogel matrix, ultimately producing a porous ceramic with a magnesium aluminum spinel structure mixed with silica aerogel. The crystal structure of this crystal determines that the resulting porous ceramic has high flexural strength and low coefficient of thermal expansion. At the same time, because the nanopores and three-dimensional network structure of silica aerogel disrupt the heat conduction path, the resulting porous ceramic has low thermal conductivity. Therefore, after setting a heating layer on the porous ceramic, the heat can be concentrated in the heating layer during the atomization of e-liquid, thereby improving atomization efficiency, making the flavor more abundant, and at the same time, the power consumption is lower.

[0109] It should be noted that the high flexural strength of Comparative Example 1 is due to its low porosity and small pore size, which makes the porous ceramic more compact; while this application can still obtain a porous ceramic with high flexural strength while improving porosity, average pore size and thermal conductivity.

[0110] In addition, this application shortens the glue removal process by adding an inorganic pore-forming agent: graphite powder. The decomposition product of graphite powder is carbon dioxide, which is both economical and environmentally friendly, and effectively improves the through-pore ratio and porosity of the prepared porous ceramic.

[0111] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. A method for producing a porous ceramic, characterized by, The method comprises the following steps: Mixing magnesium oxide, aluminum hydroxide, silica aerogel, graphite powder, glass powder, and boron oxide uniformly to obtain a mixed powder; Mixing the mixed powder with a dispersant, a plasticizer, a binder, and deionized water uniformly to obtain a slurry; Forming the slurry into a ceramic green body by using a flow casting method; Drying, degassing, and sintering the ceramic green body to obtain a porous ceramic.

2. The porous ceramic production method according to claim 1, characterized by, In the slurry, the graphite powder accounts for 13-50wt%, the silica aerogel accounts for 20-25wt%, the magnesium oxide accounts for 6-9wt%, the aluminum hydroxide accounts for 6-9wt%, the boron oxide accounts for 3-4wt%, the glass powder accounts for 3-7wt%, the dispersant accounts for 1-2wt%, the binder accounts for 1-3wt%, the plasticizer accounts for 2-3wt%, and the deionized water accounts for 8-25wt%.

3. The method according to claim 1, wherein The graphite powder is spherical graphite with a diameter of 100-200μm and an impurity content of <1%; The magnesium oxide, the aluminum hydroxide, the silica aerogel, the glass powder, and the boron oxide are spherical particles with respective diameters of 50-150μm and purities of >99%.

4. The method according to claim 1, wherein The dispersant is one of ammonium polyacrylate and polyethylene glycol octylphenyl ether; and the plasticizer is one of dibutyl phthalate and polyethylene glycol. The binder is water glass, sodium carboxymethyl cellulose, PVA, B-76 One or a combination of polyvinyl butyral (PVB) The step of mixing the mixed powder with the dispersant, the plasticizer, the binder, and water uniformly to obtain the slurry specifically comprises: placing the mixed powder, the dispersant, the plasticizer, the binder, and water in a stirring container and stirring under vacuum for 15-30min.

5. The method of claim 1, wherein the ceramic green body is formed by a method comprising: In the step of forming the slurry into a ceramic green body by using a flow casting method, the thickness of the ceramic green body is 0.2-1.0mm; 6. The method for producing a porous ceramic according to any one of claims 1 to 5, characterized in that, After the step of forming the slurry into a ceramic green body, the method further comprises: stacking multiple layers of the ceramic green body and pressing in the thickness direction with a pressure of 10-35MPa for 5-10min. The step of drying, degassing, and sintering the ceramic green body to obtain a porous ceramic specifically comprises: heating the ceramic green body in an oxidizing atmosphere furnace at a heating rate of 0.5-1.5℃ / min, degassing at 400-500℃ for 2-4h, sintering at 900-1100℃ for 2-3h at a heating rate of 5-8℃ / min after degassing, and then cooling to room temperature in the furnace to obtain the porous ceramic.

7. The method for producing a porous ceramic according to any one of claims 1 to 5, characterized by, The porous ceramic is prepared by using the method according to any one of claims 1-7.

8. A porous ceramic, characterized by, The porous ceramic has a porosity of 65-90%, an average through-hole diameter of 25-90μm, and a bending strength of 10-35MPa.

9. The porous ceramic of claim 8, wherein, The porous ceramic is provided with a heating layer.

10. An atomizing core characterized by, ​

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