WO2025148436A1 - Preparation methods for multi-sheet porous ceramic matrices and atomization core thereof - Google Patents

Abstract

Preparation methods for multi-sheet porous ceramic matrices (10, 20, 30, 40) and an atomization core thereof. The preparation method for the multi-sheet porous ceramic matrices (10, 20, 30, 40) comprises: (1) the preparation of ceramic powders, involving: weighing a plurality of groups of components in parts by weight, comprising 25-55 parts of an aggregate, 5-40 parts of a pore former, 5-19 parts of a sintering aid, and 5-35 parts of a powder dispersing agent; (2) the preparation of casting ceramic slurries, involving: weighing a plurality of groups of components in parts by weight, comprising 40-65 parts of each group of ceramic powder, 30-50 parts of a solvent, 0.1-3 parts of a slurry dispersing agent, 1-8 parts of a plasticizer, and 1-10 parts of a binder; (3) the preparation of ceramic green bodies, involving: respectively making the plurality of groups of casting ceramic slurries into a plurality of groups of sheet-like ceramic green bodies by means of a casting process; and (4) the preparation of multi-sheet porous ceramic matrices (10, 20, 30, 40), involving: vertically stacking a plurality of ceramic green bodies of different groups and/or the same group in sequence and then laminating same into an integral body, then feeding same into a furnace for de-binding and sintering, and finally cutting same into required shapes to obtain the multi-sheet porous ceramic matrices (10, 20, 30, 40).

Description

Preparation method of multi-layer porous ceramic substrate and atomizing core thereof Technical Field

The invention belongs to the technical field of atomizer cores of electronic cigarette atomizers, and particularly relates to a multi-layer porous ceramic substrate and a preparation method of the atomizer core thereof.

Background Art

The atomizing core of the electronic atomizer is used to heat the liquid to be atomized, i.e., the atomizing liquid, and atomize it into an aerosol or vapor, steam mist or smoke for the user to inhale. The atomizing liquid can be a cigarette liquid or a solution containing medicine for health and medical purposes. The electronic atomizer can be used for electronic cigarettes.

The current atomizer core of the electronic atomizer includes a porous ceramic substrate as a liquid guide, and then a heating element such as a heating wire, a heating sheet, a heating film, etc. is attached to the liquid guide. The heating element is energized to heat the atomized liquid on the liquid guide and atomize it into an aerosol or steam, a vapor mist or a smoke. The existing porous ceramic substrate used as a liquid guide is mainly formed into a ceramic green embryo and sintered. The microporous structure inside it is single, and the pore size is not much different. The liquid guide or liquid supply speed of the liquid guide is single, which does not match the need for the heating element to have different atomized liquid consumption speeds according to different powers. The liquid supply and atomization are unbalanced, resulting in the atomization core of the electronic atomizer being prone to dry burning and carbon deposition due to insufficient liquid supply during the atomization process, and also prone to oil explosion and oil leakage due to too fast liquid supply.

Technical issues

The technical problem solved by the present invention is to overcome the deficiencies of the prior art and provide a method for preparing a multi-layer porous ceramic substrate and an atomizing core thereof.

Technical Solutions

The technical solution of the present invention is a method for preparing a multi-layer porous ceramic substrate, which includes the following process flow:

(1) Preparation of ceramic powder:

Weigh components of several groups of ceramic powders by weight, wherein the components of any group of ceramic powders include: 25-55 parts of aggregate, 5-40 parts of pore formers, 5-19 parts of sintering aids, and 5-35 parts of powder dispersants, wherein the average particle sizes of the aggregates and/or pore formers in each group of ceramic powders are different;

The aggregate is a material used to form a porous ceramic matrix skeleton after sintering, including at least one of kaolin, diatomaceous earth, alumina, silicon nitride, silicon carbide, quartz sand, glass sand, clay, feldspar powder, fused quartz, cordierite, and mullite;

The pore-forming agent is a material that vaporizes and evaporates during sintering to form micropores in the porous ceramic matrix, including at least one of graphite, starch, wood powder, flour, bean powder, polystyrene microspheres, polymethyl methacrylate microspheres, sucrose, and fiber;

The sintering aid is a material used to bond aggregates and help sinter at a suitable temperature to form a porous ceramic matrix, including at least one of boron oxide, sodium silicate, silicon oxide, potassium oxide, lithium oxide, barium oxide, magnesium oxide, calcium oxide, iron oxide, titanium oxide, zinc oxide, and zirconium oxide;

The powder dispersant is a material used to promote uniform dispersion of aggregates to prevent precipitation and accumulation, including at least one of paraffin, beeswax, boric acid, oleic acid, stearic acid, polyethylene, polypropylene, polyvinyl acetate, polyvinyl acetal, ethylene-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate copolymer resin, perchlorethylene resin, polyacrylate, and polyamide;

The aggregates, pore formers, sintering aids and powder dispersants weighed in several groups are fully mixed in groups to obtain several groups of ceramic powders;

(2) Preparation of tape-cast ceramic slurry:

Weigh several groups of tape-cast ceramic slurry components by weight, wherein the components of each group of tape-cast ceramic slurry respectively include: 40 to 65 parts of ceramic powder of one of the several groups of ceramic powders, 30 to 50 parts of solvent, 0.1 to 3 parts of slurry dispersant, 1 to 8 parts of plasticizer, and 1 to 10 parts of binder;

The solvent is a material used to convert ceramic powder into a fluid, including at least one of ethanol, isopropanol, acetone, butanone, xylene, trichloroethylene, ethyl acetate, and butyl acetate;

The slurry dispersant is a material used to disperse the ceramic powder in the solvent, including at least one of oleic acid, boric acid, linseed oil, castor oil, stearic acid, and triolein;

The plasticizer is a material used to improve the plasticity of the ceramic green body, including at least one of polyethylene glycol and dibutyl phthalate;

The binder is a material used to improve the strength of the ceramic green body, including at least one of polymethyl acrylate, ethyl cellulose, polyethylene, polyvinyl butyral, and polyisobutylene;

The ceramic powder, dispersant and solvent of several groups are weighed and fully mixed and ball-milled respectively, and then the plasticizer and binder are added respectively, and then fully mixed and ball-milled to obtain several groups of tape-cast ceramic slurries;

(3) Preparation of ceramic green body:

The plurality of groups of tape-cast ceramic slurries are respectively made into a plurality of thin-sheet ceramic green embryos by tape-casting process, and the plurality of groups of ceramic green embryos are respectively cut into a plurality of ceramic green embryos;

(4) Preparation of multi-layer porous ceramic matrix:

Select a plurality of ceramic green sheets from different groups and/or different sheets from the same group, stack them up and down in the order of the average particle size of the aggregate and/or pore-forming agent contained in each ceramic green sheet, press them into a whole, and then send them into a furnace for debinding and sintering. After sintering, take them out and cut them into a desired shape, so as to obtain a multi-layer porous ceramic matrix having a plurality of ceramic sheets and vesicular micropores uniformly distributed inside, wherein a piece of the ceramic green sheet constitutes a layer of the ceramic sheet after sintering.

Preferably, when preparing a multi-layer porous ceramic matrix, several groups of ceramic green embryos and 1 to several ceramic green embryos in each group are selected, and the groups of ceramic green embryos are stacked from bottom to top in sequence and pressed into one body in the order that the average particle size of the aggregate and/or pore-forming agent contained in each group changes alternately or changes gradually from large to small, so that after debinding and sintering, a multi-layer porous ceramic matrix having several levels of ceramic sheets and each level having 1 to several ceramic sheets is obtained, the average pore size of the micropores in the ceramic sheets of the same level but different layers is the same, the average pore size of the micropores in the ceramic sheets of different levels is different, and the average pore size of the micropores in the ceramic sheets of the several levels is arranged in a bottom-up order, and the average pore size of the micropores in each level has a rule of alternating size or changing gradually from large to small.

Preferably, when preparing each group of the ceramic powder, the components of the ceramic powder weighed in parts by weight include: 35-55 parts of the aggregate, 25-30 parts of the pore former, 15-19 parts of the sintering aid, and 5-10 parts of the powder dispersant.

Preferably, it is characterized in that when preparing each group of the tape-cast ceramic slurry, the components of the tape-cast ceramic slurry weighed in parts by weight include: 45 to 55 parts of ceramic powder from one of the several groups of ceramic powders, 35 to 45 parts of solvent, 0.1 to 1 part of slurry dispersant, 1 to 5 parts of plasticizer, and 3 to 8 parts of binder.

Preferably, the average particle size of the aggregate is 5 to 100 um, or 5 to 50 um, or 10 to 30 um.

Preferably, the average particle size of the pore former is 5 to 100 um, or 15 to 80 um, or 25 to 60 um.

Preferably, when preparing the ceramic green body, a tape casting process is used to make each piece of the ceramic green body with a thickness of 0.1 to 0.6 mm, or 0.1 to 0.3 mm, or 0.25 to 0.45 mm, or 0.3 to 0.6 mm.

Preferably, the average pore size of the micropores of each ceramic layer of the multi-layer porous ceramic substrate is 10 to 50 um, or 15 to 45 um, or 20 to 40 um.

Preferably, the porosity of the micropores of each ceramic sheet layer of the multi-layer porous ceramic substrate is 40%-65%, or 45-60%, or 48-56%.

Preferably, the thickness of each ceramic sheet layer of the multi-layer porous ceramic substrate is 0.1-0.5 mm, or 0.1-0.25 mm, or 0.2-0.4 mm, or 0.25-0.5 mm.

Preferably, when preparing the multi-layer porous ceramic matrix, several groups of ceramic green embryos and one ceramic green embryo in each group are selected, and the groups of ceramic green embryos are stacked from bottom to top in the order of the average particle size of the aggregate and/or pore-forming agent contained in each group of ceramic green embryos from large to small, and then pressed into one body, so that after debinding and sintering, the multi-layer porous ceramic matrix having several levels of ceramic sheets and one ceramic sheet in each level is obtained.

Preferably, when preparing the multi-layer porous ceramic matrix, 4 to 10 groups of the ceramic green sheets are selected, and the number of ceramic layers of the porous ceramic matrix is 4 to 10 and the number of layers is 4 to 10.

Preferably, when preparing the multi-layer porous ceramic matrix, 4 to 6 groups of the ceramic green sheets are selected, and the number of ceramic sheets of the porous ceramic matrix is 4 to 6 levels and the number of layers is 4 to 6.

Preferably, when preparing the multi-layer porous ceramic matrix, 4 groups, i.e., 4 pieces of the ceramic green body, are selected, wherein, in the order of stacking from bottom to top, the weight parts of the aggregate contained in the first ceramic green body are 40 to 46 parts, the average particle size of the aggregate is 70 to 75 um, the weight parts of the pore former are 25 to 28 parts, and the average particle size of the pore former is 40 to 50 um; the weight parts of the aggregate contained in the second ceramic green body are 45 to 50 parts, the average particle size of the aggregate is 40 to 60 um, and the weight parts of the pore former are The weight of the aggregate contained in the third ceramic green body is 40-48 parts, the average particle size of the aggregate is 15-30um, the weight of the pore former is 25-30 parts, and the average particle size of the pore former is 35-40um; the weight of the aggregate contained in the fourth ceramic green body is 35-45 parts, the average particle size of the aggregate is 10-20um, the weight of the pore former is 25-30 parts, and the average particle size of the pore former is 35-40um.

Preferably, when preparing the multi-layer porous ceramic matrix, 4 groups, i.e. 4 pieces of the ceramic green embryos, are selected to obtain 4 ceramic layers of the porous ceramic matrix, wherein, in the order of stacking from bottom to top, the pore size of the micropores in the first ceramic layer is 40-50um, the pore size of the micropores in the second ceramic layer is 30-40um, the pore size of the micropores in the third ceramic layer is 20-30um, and the pore size of the micropores in the fourth ceramic layer is 10-20um.

Preferably, when preparing the multi-layer porous ceramic matrix, several groups of ceramic green embryos and two ceramic green embryos in each group are selected, and the groups of ceramic green embryos are stacked from bottom to top in the order of the average particle size of the aggregate and/or pore-forming agent contained in each group of ceramic green embryos from large to small, and then pressed into one body, so that after debinding and sintering, the multi-layer porous ceramic matrix having several levels of ceramic sheets and two ceramic sheets in each level is obtained.

Preferably, when preparing the multi-layer porous ceramic matrix, the number of groups of the ceramic green body is selected to be 2 to 5, the level of the multi-layer porous ceramic matrix is 2 to 5, and the number of ceramic layers is twice the level.

Preferably, when preparing the multi-layer porous ceramic matrix, the number of groups of the ceramic green body is selected to be 3 or 4, the number of levels of the porous ceramic matrix is obtained to be 3 or 4, and the number of ceramic layers is 6 or 8.

Preferably, when preparing the multi-layer porous ceramic matrix, the number of groups of the ceramic green embryos is selected to be 3, wherein, in the order of stacking from bottom to top, the weight of the aggregate contained in the first group of ceramic green embryos is 40 to 46 parts, the average particle size of the aggregate is 60 to 75 um, the weight of the pore former is 25 to 30 parts, and the average particle size of the pore former is 40 to 50 um; the weight of the aggregate contained in the second group of ceramic green embryos is 40 to 48 parts, the average particle size of the aggregate is 15 to 50 um, the weight of the pore former is 25 to 30 parts, and the average particle size of the pore former is 35 to 40 um; the weight of the aggregate contained in the third group of ceramic green embryos is 35 to 45 parts, the average particle size of the aggregate is 10 to 20 um, the weight of the pore former is 25 to 30 parts, and the average particle size of the pore former is 35 to 40 um.

Preferably, when preparing the multi-layer porous ceramic matrix, the number of groups of the ceramic green body is selected to be 3, the number of ceramic layers of the porous ceramic matrix is 3, and the number of ceramic layers is 6. Among them, in the order of stacking from bottom to top, the pore size of the micropores in the first-level ceramic layer is 35-50um, the pore size of the micropores in the second-level ceramic layer is 20-35um, and the pore size of the micropores in the third-level ceramic layer is 10-20um.

Preferably, when preparing the multi-layer porous ceramic matrix, the number of groups of the ceramic green embryos is selected to be 4 groups, wherein, in the order of stacking from bottom to top, the weight parts of the aggregate contained in the first group of ceramic green embryos are 40 to 46 parts, the average particle size of the aggregate is 70 to 75 um, the weight parts of the pore former are 25 to 28 parts, and the average particle size of the pore former is 40 to 50 um; the weight parts of the aggregate contained in the second group of ceramic green embryos are 45 to 50 parts, the average particle size of the aggregate is 40 to 60 um, and the weight parts of the pore former are The weight parts of the aggregate in the third group of ceramic green bodies are 40-48 parts, the average particle size of the aggregate is 15-30um, the weight parts of the pore former are 25-30 parts, and the average particle size of the pore former is 35-40um; the weight parts of the aggregate in the fourth group of ceramic green bodies are 35-45 parts, the average particle size of the aggregate is 10-20um, the weight parts of the pore former are 25-30 parts, and the average particle size of the pore former is 35-40um.

Preferably, when preparing the multi-layer porous ceramic matrix, the number of groups of the ceramic green body is selected to be 4, the number of levels of the multi-layer porous ceramic matrix obtained is 4, and the number of ceramic layers is 8, wherein, in the order of stacking from bottom to top, the pore size of the micropores in the first-level ceramic layer is 40-50um, the pore size of the micropores in the second-level ceramic layer is 30-40um, the pore size of the micropores in the third-level ceramic layer is 20-30um, and the pore size of the micropores in the fourth-level ceramic layer is 10-20um.

Another technical solution of the present invention is a method for preparing a multi-layer porous ceramic atomization core. First, a multi-layer porous ceramic substrate is prepared according to the above-mentioned method for preparing a multi-layer porous ceramic substrate, and then a metal slurry is prepared. One of the upper and lower surfaces of the multi-layer porous ceramic substrate is selected as an atomization surface, and the other surface is used as a liquid guide surface. The metal slurry is printed on both ends of the atomization surface by screen printing and sintered to obtain an electrode layer. Finally, a metal heating layer is obtained on the atomization surface by a metal sputtering coating process or by screen printing another metal slurry and then sintering. The metal heating layer covers the electrode layer, so as to obtain a multi-layer porous ceramic atomization core.

Preferably, one side with smaller pore size of micropores is selected as the atomizing surface among the upper and lower sides of the multi-layer porous ceramic substrate, and the other side is selected as the liquid guiding surface. A metal heating layer is obtained on the atomizing surface by a metal sputtering coating process or by a screen printing metal slurry followed by sintering process, thus obtaining a multi-layer porous ceramic atomizing core.

Beneficial Effects

Different from the existing porous ceramics with a single pore structure, the present invention adopts a tape casting process to prepare multiple groups of ceramic green sheets with continuous different particle size structures, and stacks and presses the multiple ceramic green sheets and fires them to obtain a porous ceramic matrix with multiple layers of different pore sizes, especially a multi-layer porous ceramic matrix with a gradient pore size structure. The ceramic green sheets are formed by multi-layer stacking. Compared with the one-time forming process, after the multi-layer ceramic green sheets are pressed and sintered, an interlayer interface will be generated at the microscopic level. The micropore diameter of the interlayer interface is between the micropore diameters of the two layers, which has a certain transition and buffering effect on the transmission of the atomized liquid, and is conducive to the storage and transmission of the atomized liquid. In addition, porous ceramics with a gradient pore size structure can be prepared by stacking multiple layers of ceramic sheets. When applied to the atomization core of an electronic cigarette, the ceramic pore size structure can be gradiently adjusted according to the ceramic sheets based on different heating methods and different viscosities of the smoke liquid. The porosity and pore size from the liquid guide surface to the atomization surface are adjusted layer by layer, so that the liquid supply and atomization of the porous ceramic matrix are balanced, achieving the advantages of both fast liquid guide and fine atomization, and improving the atomization experience.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a perspective schematic diagram of a ceramic green body according to an embodiment of the present invention;

FIG2 is a three-dimensional schematic diagram of four groups of ceramic green sheets stacked in Example 1 of the present invention;

FIG3 is a cross-sectional view of a multi-layer porous ceramic substrate according to Embodiment 1 of the present invention;

FIG4 is a three-dimensional schematic diagram of two ceramic green sheets stacked in the same group according to the second embodiment of the present invention;

FIG5 is a three-dimensional schematic diagram of three groups of ceramic green sheets stacked in Example 2 of the present invention;

FIG6 is a cross-sectional view of a three-level multi-layer porous ceramic substrate according to a second embodiment of the present invention;

FIG7 is a three-dimensional schematic diagram of four groups of ceramic green sheets stacked in Example 3 of the present invention;

FIG8 is a cross-sectional view of a 4-level multi-layer porous ceramic substrate according to Embodiment 3 of the present invention;

FIG9 is an upright three-dimensional exploded view of a multi-layer porous ceramic atomizing core according to Embodiments 4 and 5 of the present invention;

FIG. 10 is an inverted three-dimensional exploded view of the multi-layer porous ceramic atomization core of Embodiments 4 and 5 of the present invention.

Best Mode for Carrying Out the Invention

In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. In order to facilitate the description and better illustrate the present invention and its embodiments, the terms or descriptions indicating direction or position relationship such as "upper", "lower", "upright", "inverted" in this document all refer to the direction or position of the device or component placed in the accompanying drawings, and are not used to limit the indicated device, component or component to have a specific orientation, or to be constructed and operated in a specific orientation. In the case of changing the direction and position, the above-mentioned orientation terms will also change accordingly. In addition, there are terms such as "first", "second"... which are mainly used to distinguish different devices, components or components, and are not used to indicate or imply the relative importance or absolute order and quantity of the indicated devices, components or components.

The present invention will be further described in detail below with reference to the embodiments:

The present invention provides a method for preparing a multi-layer porous ceramic substrate, comprising the following process flow:

(1) Preparation of ceramic powder:

Components of several groups of ceramic powders are weighed respectively by weight, wherein the components of any group of ceramic powders include: 25-55 parts of aggregate, 5-40 parts of pore formers, 5-19 parts of sintering aids, and 5-35 parts of powder dispersants, wherein the average particle size of the aggregate and/or pore formers contained in each group of ceramic powders is different, that is, the average particle size of the aggregate and/or pore formers contained in each group of ceramic powders is different from the average particle size of the aggregate and/or pore formers contained in the remaining groups of ceramic powders.

Wherein, 25 to 55 parts of aggregate, including but not limited to: any integer between 25 and 55 parts, and\or 25 to 30 parts, and\or 30 to 35 parts, and\or 35 to 40 parts, and\or 40 to 45 parts, and\or 45 to 50 parts, and\or 50 to 55 parts, and\or 35 to 55 parts;

The pore-forming agent is 5 to 40 parts, including but not limited to: any integer between 5 and 40 parts, and\or 5 to 10 parts, and\or 10 to 15 parts, and\or 15 to 20 parts, and\or 20 to 25 parts, and\or 25 to 30 parts, and\or 30 to 35 parts, and\or 35 to 40 parts;

The sintering aid is 5 to 19 parts, including but not limited to: any integer between 5 and 19 parts, and\or 5 to 10 parts, and\or 10 to 15 parts, and\or 15 to 19 parts;

Wherein the powder dispersant is 5 to 35 parts, including but not limited to: any integer between 5 and 35 parts, and\or 5 to 10 parts, and\or 10 to 15 parts, and\or 15 to 20 parts, and\or 20 to 25 parts, and\or 25 to 30 parts, and\or 30 to 35 parts;

The aggregate is a material used to form a porous ceramic matrix skeleton after sintering, including at least one of kaolin, diatomaceous earth, alumina, silicon nitride, silicon carbide, quartz sand, glass sand, clay, feldspar powder, fused quartz, cordierite, and mullite;

The average particle size of the aggregate is 5 to 100 um, including but not limited to: any value between 5 and 100 um, and\or 5 to 10 um, and\or 10 to 20 um, and\or 20 to 30 um, and\or 30 to 40 um, and\or 40 to 50 um, and\or 50 to 60 um, and\or 60 to 70 um, and\or 70 to 80 um, and\or 80 to 90 um, and\or 90 to 100 um, and\or 5 to 50 um, and\or 10 to 30 um, and\or 50 to 100 um, and\or 55 to 85 um.

The pore-forming agent is a material that vaporizes and evaporates during sintering to form micropores in the porous ceramic matrix, including at least one of graphite, starch, wood powder, flour, bean powder, polystyrene microspheres, polymethyl methacrylate microspheres, sucrose, and fiber;

The average particle size of the pore former is 5 to 100 um, including but not limited to: any value between 5 and 100 um, and\or 5 to 10 um, and\or 10 to 20 um, and\or 20 to 30 um, and\or 30 to 40 um, and\or 40 to 50 um, and\or 50 to 60 um, and\or 60 to 70 um, and\or 70 to 80 um, and\or 80 to 90 um, and\or 90 to 100 um, and\or 5 to 50 um, and\or 50 to 100 um, and\or 15 to 80 um, and\or 25 to 60 um, and\or 55 to 95 um, and\or 65 to 85 um.

The sintering aid is used to bond the aggregate and help sinter at a suitable temperature to form a porous ceramic matrix, including at least one of boron oxide, sodium silicate, silicon oxide, potassium oxide, lithium oxide, barium oxide, magnesium oxide, calcium oxide, iron oxide, titanium oxide, zinc oxide, and zirconium oxide;

The powder dispersant is used to promote uniform dispersion of aggregates to prevent precipitation and accumulation, and includes at least one of paraffin, beeswax, boric acid, oleic acid, stearic acid, polyethylene, polypropylene, polyvinyl acetate, polyvinyl acetal, ethylene-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate copolymer resin, perchlorethylene resin, polyacrylate, and polyamide;

Several groups of the aggregates, pore formers, sintering aids and powder dispersants weighed are fully mixed in groups to obtain several groups of ceramic powders.

(2) Preparation of tape-cast ceramic slurry:

Weigh several groups of tape-cast ceramic slurry components by weight, wherein the components of each group of tape-cast ceramic slurry respectively include: 40 to 65 parts of ceramic powder of one of the several groups of ceramic powders, 30 to 50 parts of solvent, 0.1 to 3 parts of slurry dispersant, 1 to 8 parts of plasticizer, and 1 to 10 parts of binder;

Among them, there are 40 to 65 parts of ceramic powder, including but not limited to: any integer between 40 and 65 parts, and\or 40 to 45 parts, and\or 45 to 50 parts, and\or 50 to 55 parts; and\or 55 to 60 parts, and\or 60 to 65 parts, and\or 45 to 55 parts.

The solvent is 30 to 50 parts, including but not limited to: any integer between 30 and 50 parts, and\or 31 to 35 parts, and\or 35 to 40 parts, and\or 40 to 45 parts, and\or 45 to 50 parts, and\or 35 to 45 parts;

The slurry dispersant is 0.1 to 3 parts, including but not limited to: 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1 part, 1.1 part...3 parts, and\or 0.1 to 1 part, and\or 1.1 to 2 parts, and\or 2.1 to 3 parts;

Wherein the plasticizer is 1 to 8 parts, including but not limited to: any integer between 1 to 8 parts, and\or 1 to 3 parts, and\or 3 to 5 parts, and\or 1 to 5 parts, and\or 5 to 8 parts;

The binder is 1 to 10 parts, including but not limited to: any integer between 1 and 10 parts, and\or 1 to 3 parts, and\or 3 to 5 parts, and\or 5 to 8 parts, and\or 8 to 10 parts, and\or 3 to 8 parts;

The solvent is used to convert the ceramic powder into a fluid, and includes at least one of ethanol, isopropanol, acetone, butanone, xylene, trichloroethylene, ethyl acetate, and butyl acetate;

The slurry dispersant is used to disperse the ceramic powder in the solvent, and includes at least one of oleic acid, boric acid, linseed oil, castor oil, stearic acid, and triolein;

The plasticizer is used to improve the plasticity of the ceramic green body, and includes at least one of polyethylene glycol and dibutyl phthalate;

The binder is used to improve the strength of the ceramic embryo, and includes at least one of polymethyl acrylate, ethyl cellulose, polyethylene, polyvinyl butyral, and polyisobutylene;

The ceramic powder, dispersant and solvent of several groups are weighed and fully mixed and ball-milled respectively, and then the plasticizer and binder are added respectively and continue to be fully mixed and ball-milled to obtain several groups of tape-cast ceramic slurries.

(3) Preparation of ceramic green body:

Several groups of the above-mentioned tape-cast ceramic slurries are respectively made into several groups of thin-sheet ceramic green embryos by tape-casting process, and the several groups of ceramic green embryos are respectively cut into several pieces of ceramic green embryos.

The thickness of each ceramic green body made by the casting process is 0.1 to 0.6 mm, including but not limited to: any value between 0.1 and 0.6 mm, and\or 0.1 mm, and\or 0.2 mm, and\or 0.3 mm, and\or 0.4 mm, and\or 0.5 mm, and\or 0.6 mm, and\or 0.1 to 0.3 mm, and or 0.25 to 0.45 mm, and or 0.3 to 0.6 mm.

(4) Preparation of multi-layer porous ceramic matrix:

Select a plurality of ceramic green sheets from different groups and/or different sheets in the same group, stack them up and down in the order of the average particle size of the aggregate and/or pore-forming agent contained in each ceramic green sheet, press them into one body, and then send them into a furnace for debinding and sintering. After sintering, take them out and cut them into a desired shape, so as to obtain a multi-layer porous ceramic matrix having a plurality of ceramic sheets and vesicular micropores uniformly distributed inside, wherein a ceramic green sheet constitutes a ceramic sheet after sintering, and the micropores in the multi-layer porous ceramic matrix have different or the same pore size according to the ceramic sheets.

The multi-layer porous ceramic matrix of the present invention has spherical or nearly spherical bubble-shaped micropores formed inside, the distance between the micropores is relatively close, and some adjacent micropores are connected by tiny through holes. Therefore, the entire multi-layer porous ceramic matrix can be used as a liquid conductor to absorb liquid substances from one side and conduct them to the other side for seepage after adsorption, penetration and flow through the micropores.

The average pore size of the micropores of each ceramic layer in the above-mentioned multi-layer porous ceramic matrix is 10 to 50 um, including but not limited to any value between 10 and 50 um, and\or 10 to 20 um, and\or 20 to 30 um, and\or 30 to 40 um, and\or 40 to 50 um, and\or 15 to 45 um, and\or 20 to 40 um.

The porosity of the micropores of each ceramic layer of the prepared multi-layer porous ceramic matrix is 40%-65%, including but not limited to any value between 40%-65%, and\or 40%-45%, and\or 45%-50%, and\or 50%-55%, and\or 55%-60%, and\or 60%-65%, and\or 45-60%, and\or 48-56%.

The thickness of each ceramic layer of the multi-layer porous ceramic matrix is 0.1 to 0.5 mm, including but not limited to any value between 0.1 and 0.5 mm, and\or 0.1 mm, and\or 0.2 mm, and\or 0.3 mm, and\or 0.4 mm, and\or 0.5 mm, and\or 0.1 to 0.25 mm, and or 0.2 to 0.4 mm, and or 0.25 to 0.5 mm.

The average pore size, porosity and thickness structure of the above micropores enable the multi-layer porous ceramic matrix to have good conduction ability for conducting liquid substances under external forces such as suction, and not to flow too fast, and have a certain balance ability. When there is no external force such as suction, the micropores have a certain tension, which can absorb the column liquid substances without flowing naturally and seeping out to cause dripping. The multi-layer porous ceramic matrix of the present invention can be used for conducting liquids for conducting atomized liquids.

In addition, the preparation method of the above-mentioned multi-layer porous ceramic matrix, wherein when preparing the multi-layer porous ceramic matrix, several ceramic green embryos of different groups and/or different sheets of the same group are selected, and the average particle size of the aggregate and/or pore-forming agent contained in each ceramic green embryo is used as the arrangement order, and then they are stacked up and down and pressed into one body, wherein the arrangement order according to the average particle size of the aggregate and/or pore-forming agent means stacking the ceramic green embryos according to a certain rule, that is, based on the average particle size of the aggregate and/or pore-forming agent in the ceramic green embryo, according to the rule of from large to small, or from small to large, or one large and one small, or two the same and then from large to small, or the rule of alternating size, so that the size of the micropores of each layer of ceramic sheet after preparation is also arranged according to the above rule.

When preparing a multi-layer porous ceramic matrix, several groups of ceramic green embryos and 1 to several ceramic green embryos in each group can be selected, for example, 2 to 10 groups of ceramic green embryos and 1 to 3 ceramic green embryos in each group can be selected, and the groups of ceramic green embryos are stacked from bottom to top in sequence according to the order in which the average particle size of the aggregate and/or pore-forming agent contained in each group of ceramic green embryos changes alternately or changes gradually from large to small, and then pressed into one body, so that after debinding and sintering, a multi-layer porous ceramic matrix with several levels of ceramic sheets and 1 to several layers of ceramic sheets in each level is obtained, for example, a multi-layer porous ceramic matrix with 2 to 10 levels of ceramic sheets and 1 to 3 layers of ceramic sheets in each level is obtained, the average pore size of the micropores in the ceramic sheets of the same level and different layers is the same, the average pore size of the micropores in the ceramic sheets of different levels is different, and the average pore size of the micropores in the ceramic sheets of several levels in the order from bottom to top has a rule of alternating size or changing gradually from large to small.

For example, one piece of each group of ceramic green sheets with different average particle size ranges of aggregates and/or pore formers can be selected, and the ceramic green sheets are stacked from bottom to top in the order of the average particle size ranges of aggregates and/or pore formers, to obtain a multi-layer porous ceramic matrix, in which the micropore diameters of each ceramic sheet layer from bottom to top in the multi-layer porous ceramic matrix have a gradient change from large to small. Including, when preparing a multi-layer porous ceramic matrix, the number of groups of ceramic green sheets, i.e., the number of sheets, is selected to be 4 to 10, preferably 4 to 6, and the number of ceramic sheets of the porous ceramic matrix is 4 to 10 layers, preferably 4 to 6 layers.

For another example, two ceramic green sheets with the same average particle size range of aggregates and/or pore formers can be selected and stacked together to form a group, and then two ceramic green sheets with the same average particle size range of aggregates and/or pore formers can be selected and stacked together to form another group, so as to prepare several groups of ceramic green sheets with different average particle size ranges, and stack each group of ceramic green sheets from bottom to top in the order of the average particle size range of aggregates and/or pore formers from large to small, so as to obtain a multi-level multi-layer porous ceramic matrix with two ceramic sheets as one level, and the micropore diameters of each level from bottom to top in the multi-layer porous ceramic matrix have a gradient change from large to small. Among them, when preparing a multi-layer porous ceramic matrix, the number of groups of ceramic green sheets is selected to be 2 to 5 groups, preferably 3 or 4 groups, the number of levels of the porous ceramic matrix is 2 to 5, the number of ceramic sheets is twice the number of levels, preferably 3 or 4, and the number of ceramic sheets is 6 or 8.

It should be particularly noted that when the multi-layer porous ceramic substrate of the present invention is manufactured, due to the stacking and pressing of the ceramic green embryos, the thickness of each layer of the ceramic green embryo will be slightly greater than the thickness of each layer of the ceramic sheet after sintering. The multi-layer porous ceramic substrate after sintering is actually a whole, and no obvious stratification can be seen from the appearance and cross-section, which is generally difficult to distinguish with the naked eye. The levels and layer-by-layer analysis of the ceramic sheets described in this article are just grading and stratification based on the size of the micropores inside each level and each layer of the ceramic sheets.

The present invention provides a method for preparing a multi-layer porous ceramic atomization core. First, a multi-layer porous ceramic substrate is prepared according to the above-mentioned method for preparing a multi-layer porous ceramic substrate, and then a metal slurry is prepared. One of the upper and lower surfaces of the multi-layer porous ceramic substrate is selected as an atomization surface, and the other surface is used as a liquid guide surface. The metal slurry is printed on both ends of the atomization surface by screen printing and sintered to obtain an electrode layer. Finally, a metal heating layer is obtained on the atomization surface by a metal sputtering coating process or by a process of screen printing another metal slurry and then sintering, so as to obtain a multi-layer porous ceramic atomization core.

The method for preparing the above-mentioned multi-layer porous ceramic atomization core can preferably be as follows: among the upper and lower surfaces of the multi-layer porous ceramic substrate, one side with a smaller pore size of the micropores is selected as the atomization surface, and the other side is used as the liquid guide surface. A metal heating layer is obtained on the atomization surface by a metal sputtering coating process or by a screen printing metal slurry followed by sintering, thereby obtaining a multi-layer porous ceramic atomization core.

The multi-layer porous ceramic matrix and its atomizing core prepared by the present invention are different from the existing porous ceramics with a single pore structure. The present invention adopts a tape casting process to prepare multiple groups of ceramic green embryos with continuous different particle size structures, and stacks and presses the multiple ceramic green embryos and fires them to obtain a porous ceramic matrix with multiple layers of different pore sizes, especially a multi-layer porous ceramic matrix with a gradient pore size structure. The ceramic green embryo is formed by multi-layer stacking. Compared with the one-time forming process, after the multi-layer ceramic green embryo is pressed and sintered, an interlayer interface will be generated at the microscopic level. The micropore diameter of the interlayer interface is between the micropore diameters of the two layers, which has a certain transition and buffering effect on the transmission of the atomized liquid, which is beneficial to the storage and transmission of the atomized liquid. In addition, porous ceramics with a gradient pore size structure can be prepared by stacking multiple layers of ceramic sheets. When applied to the atomization core of an electronic cigarette, the ceramic pore size structure can be gradiently adjusted according to the ceramic sheets based on different heating methods and different viscosities of the smoke liquid. The porosity and pore size from the liquid guide surface to the atomization surface are adjusted layer by layer, so that the liquid supply and atomization of the porous ceramic matrix are balanced, achieving the advantages of both fast liquid guide and fine atomization, and improving the atomization experience.

Embodiments of the present invention

The present invention will be described in detail below with reference to the specific drawings.

Example 1:

A method for preparing a multi-layer porous ceramic substrate includes the following process flow:

(1) Preparation of ceramic powder:

As shown in the above table, first weigh the components of the first group of ceramic powders by weight: 40 to 46 parts of aggregates with an average particle size of 70 to 75um, 25 to 28 parts of pore formers with an average particle size of 40 to 50um, 5 to 19 parts of sintering aids, and 5 to 35 parts of powder dispersants;

The components of the second group of ceramic powders are weighed by weight: 45-50 parts of aggregates, the average particle size of the aggregates is 40-60um, 20-25 parts of pore formers, the average particle size of the pore formers is 40-50um, 5-19 parts of sintering aids, and 5-35 parts of powder dispersants;

The components of the third group of ceramic powders are weighed by weight: 40-48 parts of aggregates, the average particle size of the aggregates is 15-30 um, 25-30 parts of pore formers, the average particle size of the pore formers is 35-40 um, 5-19 parts of sintering aids, and 5-35 parts of powder dispersants;

The components of the fourth group of ceramic powders weighed by weight include: 35-45 parts of aggregates with an average particle size of 10-20um, 25-30 parts of pore formers with an average particle size of 35-40um, 5-19 parts of sintering aids, and 5-35 parts of powder dispersants.

The above-mentioned sintering aid is 5 to 19 parts, including any integer between 5 and 19 parts, and\or 5 to 10 parts, and\or 10 to 15 parts, and\or 15 to 19 parts;

Wherein the above-mentioned powder dispersant is 5 to 35 parts, including any integer between 5 and 35 parts, and\or 5 to 10 parts, and\or 10 to 15 parts, and\or 15 to 20 parts, and\or 20 to 25 parts, and\or 25 to 30 parts, and\or 30 to 35 parts;

The aggregate is at least one of kaolin, diatomaceous earth, alumina, silicon nitride, silicon carbide, quartz sand, glass sand, clay, feldspar powder, fused quartz, cordierite and mullite;

The pore-forming agent is at least one of graphite, starch, wood powder, flour, soybean powder, polystyrene microspheres, polymethyl methacrylate microspheres, sucrose, and fiber;

The sintering aid is at least one of boron oxide, sodium silicate, silicon oxide, potassium oxide, lithium oxide, barium oxide, magnesium oxide, calcium oxide, iron oxide, titanium oxide, zinc oxide, and zirconium oxide;

The powder dispersant is at least one of paraffin, beeswax, boric acid, oleic acid, stearic acid, polyethylene, polypropylene, polyvinyl acetate, polyvinyl acetal, ethylene-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate copolymer resin, perchlorethylene resin, polyacrylate, and polyamide;

The above four groups of aggregates, pore formers, sintering aids and powder dispersants are weighed and fully mixed in groups to obtain four groups of ceramic powders including the first group to the fourth group.

(2) Preparation of tape-cast ceramic slurry:

Components of 4 groups of tape-cast ceramic slurries were weighed respectively by weight, wherein the components of each group of tape-cast ceramic slurries include: 40-65 parts of ceramic powder of one of the above 4 groups of ceramic powders, 30-50 parts of solvent, 0.5-3 parts of slurry dispersant, 1-8 parts of plasticizer, and 1-10 parts of binder.

Among them, the ceramic powder is 40 to 65 parts, including any integer between 40 and 65 parts, and\or 40 to 45 parts, and\or 45 to 50 parts, and\or 50 to 55 parts, and\or 55 to 60 parts, and\or 55 to 60 parts.

Wherein the above-mentioned solvent is 30 to 50 parts, including any integer between 30 and 50 parts, and\or 30 to 35 parts, and\or 35 to 40 parts, and\or 40 to 45 parts, and\or 45 to 50 parts;

The above-mentioned slurry dispersant is 0.5 to 3 parts, including any value between 0.5 and 3, and\or 0.5 to 1 part, and\or 1 to 1.5 parts, and\or 1.5 to 2 parts, and\or 2 to 2.5 parts, and\or 2.5 to 3 parts;

The above-mentioned plasticizer is 1 to 8 parts, including any integer between 1 to 8 parts, and\or 1 to 3 parts, and\or 3 to 6 parts, and\or 6 to 8 parts, and\or 2 to 5 parts;

The above-mentioned binder is 1 to 10 parts, including any integer between 1 and 10 parts, and\or 1 to 3 parts, and\or 3 to 6 parts, and\or 6 to 9 parts, and\or 3 to 8 parts;

The solvent is used to convert the ceramic powder into a fluid, and includes at least one of ethanol, isopropanol, acetone, butanone, xylene, trichloroethylene, ethyl acetate, and butyl acetate;

The slurry dispersant is used to disperse the ceramic powder in the solvent, and includes at least one of oleic acid, boric acid, linseed oil, castor oil, stearic acid, and triolein;

The plasticizer is used to improve the plasticity of the ceramic green body, and includes at least one of polyethylene glycol and dibutyl phthalate;

The binder is used to improve the strength of the ceramic green body, and includes at least one of polymethyl acrylate, ethyl cellulose, polyethylene, polyvinyl butyral, and polyisobutylene;

The weighed ceramic powders, dispersants and solvents of the above four groups are mixed and ball-milled respectively, and then plasticizers and binders are added respectively, and continue to be mixed and ball-milled evenly to obtain four groups of tape-cast ceramic slurries, including tape-cast ceramic slurries of groups 1 to 4.

(3) Preparation of ceramic green body:

The tape-cast ceramic slurries of the first to fourth groups are respectively made into four groups of thin-sheet ceramic green embryos 1 by tape-casting process, and the four groups of ceramic green embryos are respectively cut into a plurality of ceramic green embryos, i.e., a ceramic green embryo 1 as shown in FIG1. The thickness of each of the four groups of ceramic green embryos made by tape-casting process is 0.3 to 0.6 mm.

(4) Preparation of multi-layer porous ceramic matrix:

As shown in FIG2 , the first to fourth groups of cast ceramic slurries are used to prepare the first group of ceramic green embryos 11, the twelfth group of ceramic green embryos 12, the third group of ceramic green embryos 13, and the fourth group of ceramic green embryos 14, respectively. One piece of the ceramic green embryos from each of the above different groups are stacked from bottom to top in the order of the first group of ceramic green embryos 11 to the fourth group of ceramic green embryos 14, and then pressed into a whole. The pieces are then sent into a furnace for debinding and sintering, and finally cut into a desired shape, so as to obtain a multi-layer porous ceramic substrate 10 having 4 ceramic layers and uniformly distributed vesicular micropores.

As shown in FIG. 3 , the multi-layer porous ceramic substrate 10 includes, from bottom to top, a first ceramic layer 110 , a second ceramic layer 120 , a third ceramic layer 130 , and a fourth ceramic layer 140 .

The multi-layer porous ceramic substrate 10 prepared by the above method has, in order from bottom to top, a pore size of 40 to 50 um in the first ceramic layer 110 of the multi-layer porous ceramic substrate, a pore size of 30 to 40 um in the second ceramic layer 120, a pore size of 20 to 30 um in the third ceramic layer 130, and a pore size of 10 to 20 um in the fourth ceramic layer 140, that is, the average pore size of the micropores in the first to third ceramic layers has a gradient change from large to small. In the figure, denser oblique lines represent smaller pore sizes, and looser lines represent larger pore sizes. The thickness of each ceramic layer of the multi-layer porous ceramic substrate is 0.25 to 0.5 mm.

Example 2

Another method for preparing a multi-layer porous ceramic substrate includes the following process flow:

(1) Preparation of ceramic powder:

As shown in the above table, first weigh the components of the first group of ceramic powders by weight: 40 to 46 parts of aggregates with an average particle size of 60 to 75 um, 25 to 30 parts of pore formers with an average particle size of 40 to 50 um, 5 to 19 parts of sintering aids, and 5 to 35 parts of powder dispersants;

The components of the second group of ceramic powders are weighed by weight: 40-48 parts of aggregates, the average particle size of the aggregates is 15-50um, 25-30 parts of pore formers, the average particle size of the pore formers is 35-40um, 5-19 parts of sintering aids, and 5-35 parts of powder dispersants;

The components of the third group of ceramic powders weighed by weight include: 35-45 parts of aggregates with an average particle size of 10-20um, 25-30 parts of pore formers with an average particle size of 35-40um, 5-19 parts of sintering aids, and 5-35 parts of powder dispersants.

The above-mentioned sintering aid 5-19 parts includes any integer between 5-19 parts, and\or 5-10 parts, and\or 10-15 parts, and\or 15-19 parts;

Wherein the above-mentioned powder dispersant 5-35 parts includes any integer between 5-35 parts, and\or 5-10 parts, and\or 10-15 parts, and\or 15-20 parts, and\or 20-25 parts, and\or 25-30 parts, and\or 30-35 parts;

The aggregate is a material used to form a porous ceramic matrix skeleton after sintering, including at least one of kaolin, diatomaceous earth, alumina, silicon nitride, silicon carbide, quartz sand, glass sand, clay, feldspar powder, fused quartz, cordierite, and mullite;

The pore-forming agent is at least one of graphite, starch, wood powder, flour, soybean powder, polystyrene microspheres, polymethyl methacrylate microspheres, sucrose, and fiber;

The sintering aid is at least one of boron oxide, sodium silicate, silicon oxide, potassium oxide, lithium oxide, barium oxide, magnesium oxide, calcium oxide, iron oxide, titanium oxide, zinc oxide, and zirconium oxide;

The powder dispersant is at least one of paraffin, beeswax, boric acid, oleic acid, stearic acid, polyethylene, polypropylene, polyvinyl acetate, polyvinyl acetal, ethylene-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate copolymer resin, perchlorethylene resin, polyacrylate, and polyamide;

The above three groups of aggregates and pore formers are fully mixed with sintering aids and powder dispersants to obtain three groups of ceramic powders, namely, ceramic powders of groups 1 to 3.

(2) Preparation of tape-cast ceramic slurry:

The following three groups of tape-cast ceramic slurries are weighed respectively by weight, wherein the components of each group of tape-cast ceramic slurries include: 40-65 parts of ceramic powder from one of the four groups of ceramic powders, 30-50 parts of solvent, 0.5-3 parts of slurry dispersant, 1-8 parts of plasticizer, and 1-10 parts of binder.

Wherein the above solvent is 30-50 parts, including any integer between 30-50 parts, and\or 30-35 parts, and\or 35-40 parts, and\or 40-45 parts, and\or 45-50 parts;

The above-mentioned slurry dispersant is 0.5 to 3 parts, including any value between 0.5 and 3, and\or 0.5 to 1 part, and\or 1 to 1.5 parts, and\or 1.5 to 2 parts, and\or 2 to 2.5 parts, and\or 2.5 to 3 parts;

The above-mentioned plasticizer is 1 to 8 parts, including any integer between 1 to 8 parts, and\or 1 to 3 parts, and\or 3 to 6 parts, and\or 6 to 8 parts, and\or 2 to 5 parts;

The above-mentioned binder is 1 to 10 parts, including any integer between 1 and 10 parts, and\or 1 to 3 parts, and\or 3 to 6 parts, and\or 6 to 9 parts, and\or 3 to 8 parts;

The solvent is used to convert the ceramic powder into a fluid, and includes at least one of ethanol, isopropanol, acetone, butanone, xylene, trichloroethylene, ethyl acetate, and butyl acetate;

The slurry dispersant is used to disperse the ceramic powder in the solvent, and includes at least one of oleic acid, boric acid, linseed oil, castor oil, stearic acid, and triolein;

The plasticizer is used to improve the plasticity of the ceramic green body, including at least one of polyethylene glycol and dibutyl phthalate;

The binder is used to improve the strength of the ceramic embryo, and includes at least one of polymethyl acrylate, ethyl cellulose, polyethylene, polyvinyl butyral, and polyisobutylene;

The three groups of weighed ceramic powders, dispersants and solvents were fully mixed and ball-milled respectively, and then plasticizers and binders were added respectively and continued to be fully mixed and ball-milled to obtain three groups of tape-cast ceramic slurries, namely, the tape-cast ceramic slurries of Groups 1 to 3.

(3) Preparation of ceramic green body:

The tape-cast ceramic slurries of the first to third groups are respectively made into three groups of thin-sheet ceramic green sheets by tape-casting process, and the three groups of ceramic green sheets are respectively cut into several pieces of ceramic green sheets, as shown in FIG. 1 .

The thickness of each ceramic green body of the above three groups made by tape casting process is 0.25-0.45 mm.

(4) Preparation of multi-layer porous ceramic matrix:

As shown in Fig. 4-Fig. 6, two pieces of ceramic green embryos are taken from each of the three different groups, and two pieces of ceramic green embryos 2 of the same group are first stacked together to form one group, and then two pieces of ceramic green embryos of another group are selected and stacked together to form another group, and the first group of ceramic green embryos 21, the second group of ceramic green embryos 22, and the third group of ceramic green embryos 23 are formed in the order of the first group to the third group of ceramic powders, and then the ceramic green embryos of each group are stacked and pressed into one piece in the order of the first group to the third group and from bottom to top, and then sent into the furnace for debinding and sintering, and finally cut into the desired shape, that is, a multi-layer porous ceramic matrix 20 with three levels and six layers of ceramic sheets and uniformly distributed vesicular micropores is obtained. As shown in Fig. 8, the multi-layer porous ceramic matrix 20 includes a first-level ceramic sheet 210, a second-level ceramic sheet 220, and a third-level ceramic sheet 230 from bottom to top, and each level includes the same two layers of ceramic sheets.

The multi-layer porous ceramic substrate 20 prepared by the above method has, in order from bottom to top, a pore size of 35-50um in the first level 210 of the multi-layer porous ceramic substrate, a pore size of 20-35um in the second level 220, and a pore size of 10-20um in the third level 230 of the micropores. That is, the average pore size of the micropores in the first to third level ceramic sheets has a gradient change from large to small. In the figure, the level or ceramic sheet with denser shaded oblique lines represents a smaller pore size, and the looser represents a larger pore size.

The thickness of each ceramic layer of the multi-layer porous ceramic substrate is 0.2-0.4 mm.

Embodiment 3:

Another method for preparing a multi-layer porous ceramic substrate includes the following process flow:

(1) Preparation of ceramic powder:

As shown in the above table, first weigh the components of the first group of ceramic powders by weight: 40 to 46 parts of aggregates with an average particle size of 70 to 75um, 25 to 28 parts of pore formers with an average particle size of 40 to 50um, 5 to 19 parts of sintering aids, and 5 to 35 parts of powder dispersants;

The components of the second group of ceramic powders are weighed by weight: 45-50 parts of aggregates, the average particle size of the aggregates is 40-60um, 20-25 parts of pore formers, the average particle size of the pore formers is 40-50um, 5-19 parts of sintering aids, and 5-35 parts of powder dispersants;

The components of the third group of ceramic powders are weighed by weight: 40-48 parts of aggregates, the average particle size of the aggregates is 15-30 um, 25-30 parts of pore formers, the average particle size of the pore formers is 35-40 um, 5-19 parts of sintering aids, and 5-35 parts of powder dispersants;

The components of the fourth group of ceramic powders weighed by weight include: 35-45 parts of aggregates with an average particle size of 10-20um, 25-30 parts of pore formers with an average particle size of 35-40um, 5-19 parts of sintering aids, and 5-35 parts of powder dispersants.

The above-mentioned sintering aid 5-19 parts includes any integer between 5-19 parts, and\or 5-10 parts, and\or 10-15 parts, and\or 15-19 parts;

The above-mentioned powder dispersant 5 to 35 parts includes any integer between 5 and 35 parts, and\or 5 to 10 parts, and\or 10 to 15 parts, and\or 15 to 20 parts, and\or 20 to 25 parts, and\or 25 to 30 parts, and\or 30 to 35 parts.

The aggregate is a material used to form a porous ceramic matrix skeleton after sintering, including at least one of kaolin, diatomaceous earth, alumina, silicon nitride, silicon carbide, quartz sand, glass sand, clay, feldspar powder, fused quartz, cordierite, and mullite;

The pore-forming agent is at least one of graphite, starch, wood powder, flour, soybean powder, polystyrene microspheres, polymethyl methacrylate microspheres, sucrose, and fiber;

The sintering aid is at least one of boron oxide, sodium silicate, silicon oxide, potassium oxide, lithium oxide, barium oxide, magnesium oxide, calcium oxide, iron oxide, titanium oxide, zinc oxide, and zirconium oxide;

The powder dispersant is at least one of paraffin, beeswax, boric acid, oleic acid, stearic acid, polyethylene, polypropylene, polyvinyl acetate, polyvinyl acetal, ethylene-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate copolymer resin, perchlorethylene resin, polyacrylate, and polyamide;

The 4 groups of aggregates, pore formers, sintering aids and powder dispersants weighed are fully mixed in groups to obtain 4 groups of ceramic powders, including the ceramic powders of the above-mentioned groups 1 to 4.

(2) Preparation of tape-cast ceramic slurry:

Components of 4 groups of tape-cast ceramic slurries were weighed respectively by weight, wherein the components of each group of tape-cast ceramic slurries include: 40-65 parts of ceramic powder of one of the above-mentioned groups 1 to 4, 30-50 parts of solvent, 0.1-3 parts of slurry dispersant, 1-8 parts of plasticizer, and 1-10 parts of binder.

Wherein the above-mentioned solvent is 30 to 50 parts, including any integer between 30 and 50 parts, and\or 30 to 35 parts, and\or 35 to 40 parts, and\or 40 to 45 parts, and\or 45 to 50 parts;

The above-mentioned slurry dispersant is 0.5 to 3 parts, including any value between 0.5 and 3, and\or 0.5 to 1 part, and\or 1 to 1.5 parts, and\or 1.5 to 2 parts, and\or 2 to 2.5 parts, and\or 2.5 to 3 parts;

The above-mentioned plasticizer is 1 to 8 parts, including any integer between 1 to 8 parts, and\or 1 to 3 parts, and\or 3 to 6 parts, and\or 6 to 8 parts, and\or 2 to 5 parts;

The above-mentioned binder is 1 to 10 parts, including any integer between 1 and 10 parts, and\or 1 to 3 parts, and\or 3 to 6 parts, and\or 6 to 9 parts, and\or 3 to 8 parts;

The solvent is used to convert the ceramic powder into a fluid, and includes at least one of ethanol, isopropanol, acetone, butanone, xylene, trichloroethylene, ethyl acetate, and butyl acetate;

The slurry dispersant is used to disperse the ceramic powder in the solvent, and includes at least one of oleic acid, boric acid, linseed oil, castor oil, stearic acid, and triolein;

The plasticizer is used to improve the plasticity of the ceramic green body, including at least one of polyethylene glycol and dibutyl phthalate;

The binder is used to improve the strength of the ceramic embryo, and includes at least one of polymethyl acrylate, ethyl cellulose, polyethylene, polyvinyl butyral, and polyisobutylene;

The 4 groups of weighed ceramic powders, dispersants and solvents were fully mixed and ball-milled respectively, and then plasticizers and binders were added respectively and continued to be fully mixed and ball-milled to obtain 4 groups of tape-cast ceramic slurries, namely, the tape-cast ceramic slurries of Groups 1 to 4.

(3) Preparation of ceramic green body:

The tape-cast ceramic slurries of the first to fourth groups are respectively made into four groups of thin-sheet ceramic green sheets by tape-casting process, and the four groups of ceramic green sheets are respectively cut into several pieces of ceramic green sheets, as shown in FIG. 1 , which is a piece of ceramic green sheet 1.

The thickness of each ceramic green body made by the tape casting process is 0.1 to 0.3 mm.

(4) Preparation of multi-layer porous ceramic matrix:

As shown in Fig. 4, Fig. 7 and Fig. 8, two pieces of ceramic green embryos from each of the four different groups are taken, and two pieces of ceramic green embryos 2 from the same group are first stacked together to form a group, and the first group of ceramic green embryos 31, the second group of ceramic green embryos 32, the third group of ceramic green embryos 33, and the fourth group of ceramic green embryos 34 are formed in the order of the first group to the fourth group of ceramic powders, and then the ceramic green embryos of each group are stacked and pressed into a whole in the order of the first group to the fourth group and from bottom to top, and then sent into a furnace for debinding and sintering, and finally cut into a desired shape, that is, a multi-layer porous ceramic matrix 30 with 4 levels and 8 layers of ceramic sheets and uniformly distributed vesicular micropores is obtained. As shown in Fig. 8, the multi-layer porous ceramic matrix 30 includes a first-level ceramic sheet 310, a second-level ceramic sheet 320, a third-level ceramic sheet 330, and a fourth-level ceramic sheet 340 from bottom to top, and each level includes the same 2 layers of ceramic sheets.

The multi-layer porous ceramic substrate 30 prepared by the above method has, in order from bottom to top, a pore size of 40-50um in the first level 310 of the multi-layer porous ceramic substrate, a pore size of 30-40um in the second level 320, a pore size of 20-30um in the third level 330, and a pore size of 10-20um in the fourth level 340 of the micropores, that is, the average pore size of the micropores in the first to fourth level ceramic sheets has a gradient change from large to small. In the figure, the level or ceramic sheet with denser shaded oblique lines represents a smaller pore size, and the looser represents a larger pore size.

The thickness of each ceramic layer of the multi-layer porous ceramic substrate is 0.1-0.25 mm.

Embodiment 4:

As shown in Figures 9 and 10, a method for preparing a multi-layer porous ceramic atomization core of the present invention is as follows: first, a multi-layer porous ceramic substrate 40 is prepared on the basis of the above-mentioned embodiment, and then a metal slurry is prepared. One of the upper and lower surfaces of the multi-layer porous ceramic substrate is selected as an atomization surface 41, and the other surface is used as a liquid guide surface 42. The metal slurry is printed on both ends of the atomization surface by screen printing and sintered to obtain an electrode layer 43. Finally, a metal heating layer 44 is obtained on the atomization surface by a metal sputtering coating process or by screen printing another metal slurry and then sintering. The metal heating layer 44 covers the electrode layer 43 so that the two can be electrically connected, thereby obtaining a multi-layer porous ceramic atomization core. Both the upper and lower surfaces of the multi-layer porous ceramic matrix can be used as liquid guiding surfaces for introducing liquid substances, and the other surface is used as an atomizing surface for seeping out liquid substances. The metal heating layer 44 also has micropores or large through holes, so that the liquid substance seeping out of the atomizing surface 41 can continue to seep out through the metal heating layer, or provide gaseous substances for volatilization into the air. When the metal heating layer 44 is energized, it can heat, evaporate or atomize the liquid substance seeping out of the atomizing surface 41 to form an aerosol or aerosol, or smoke. The electrode layer 43 is used to connect the two poles of a power supply to provide electrical energy to the metal heating layer 44.

The multi-layer porous ceramic atomization core prepared by the present invention, in which the multi-layer porous ceramic matrix 40 as a liquid conductor, has bubble-shaped micropores evenly distributed in each ceramic layer, the average pore size of the micropores in the same level of ceramic layers is the same, and the average pore size of the micropores in the different levels of ceramic layers is different, and the average pore size of the micropores in the various levels of ceramic layers in a bottom-up order has a regularity of alternating size changes or gradient changes from large to small. The micropores are spherical or nearly spherical bubble-shaped micropores, the distance between the micropores is relatively close, and some adjacent micropores are connected by tiny through holes, so the entire multi-layer porous ceramic matrix can be used as a liquid conductor, which is used to absorb liquid substances from one side and conduct them to the other side for seepage after adsorption, penetration, and flow through the micropores. The liquid-conducting liquid of the multi-layer porous ceramic atomizing core of the present invention has the aforementioned micropore pore size and the thickness structure of the ceramic layer, so that the multi-layer porous ceramic matrix has a good conduction ability to conduct liquid substances under the action of external forces such as suction, and does not flow too fast, and has a certain balance ability. When there is no external force such as suction, the micropores have a certain tension, so that the liquid substance can be quickly absorbed without flowing naturally and seeping out to cause dripping. The multi-layer porous ceramic atomizing core of the present invention can be used in an electronic cigarette atomizer, and is used to heat, evaporate, and atomize the atomized liquid or electronic cigarette liquid in the electronic cigarette storage chamber.

The present invention adopts a tape casting process to prepare multiple groups of ceramic green embryos with continuous different particle size structures, and stacks and presses multiple ceramic green embryos and fires them to obtain a porous ceramic matrix with multiple layers of different pore sizes, especially a multi-layer porous ceramic matrix with a gradient pore size structure. The ceramic green embryo is formed by a multi-layer stacking method. Compared with a one-time forming process, a multi-layer ceramic green embryo will produce an interlayer interface under a microscopic level after pressing and sintering. The micropore aperture of the interlayer interface is between the micropore apertures of the two layers, which has a certain transition and buffering effect on the transmission of the atomized liquid, and is conducive to the storage and transmission of the atomized liquid. In addition, a multi-layer ceramic layer can be stacked to prepare a porous ceramic with a gradient pore size structure. When applied to the atomization core of an electronic cigarette, the ceramic pore size structure can be adjusted by a gradient according to the ceramic layer according to different heating methods and different viscosities of the smoke liquid. The porosity and pore size from the liquid guide surface to the atomization surface are adjusted layer by layer, so that the liquid supply and atomization of the porous ceramic matrix are balanced, and the advantages of fast liquid guide and delicate atomization are achieved, and the atomization experience is improved.

Figure 9 of the attached drawings of the specification shows an upright three-dimensional exploded view of the multi-layer porous ceramic atomizer core of this embodiment, and Figure 10 shows an inverted three-dimensional exploded view of the multi-layer porous ceramic atomizer core of this embodiment. In actual use, the multi-layer porous ceramic atomizer core of the present invention is generally installed in the position shown in Figure 10, so that the atomized liquid can flow from top to bottom by gravity and conduct to the metal heating layer. The position shown in Figure 9 is for the convenience of showing the electrode layer and the metal heating layer in the decomposed structure.

Embodiment 5:

As shown in Figures 9 and 10, another method for preparing a multi-layer porous ceramic atomization core of the present invention is as follows: first, a multi-layer porous ceramic substrate 40 is prepared on the basis of the above-mentioned embodiment, and then a metal slurry is prepared. The side with smaller pore size of the micropores on the upper and lower sides of the multi-layer porous ceramic substrate is selected as the atomization surface 41, and the other side is used as the liquid guide surface 42. The metal slurry is printed on both ends of the atomization surface by screen printing and sintered to obtain an electrode layer 43. A metal heating layer 44 is obtained on the atomization surface by a metal sputtering coating process or by a process of screen printing the metal slurry and then sintering, so as to obtain a multi-layer porous ceramic atomization core. In the present embodiment, the side with a smaller pore size of the micropores is selected as the atomizing surface 41, and the other side is selected as the liquid guiding surface 42, so that the atomized liquid is more easily absorbed by the liquid guiding surface. When it reaches the atomizing surface, due to the smaller pore size of the micropores, the seepage rate of the atomized liquid can be controlled, so that the liquid supply and atomization speeds are matched to better achieve a dynamic balance, thereby achieving the advantages of both fast liquid guiding and fine atomization, and improving the atomization experience of electronic cigarette atomizer users.

Industrial Applicability

The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims (24)

A method for preparing a multi-layer porous ceramic substrate, characterized in that it includes the following process flow: (1) Preparation of ceramic powder: Weigh components of several groups of ceramic powders by weight, wherein the components of any group of ceramic powders include: 25-55 parts of aggregate, 5-40 parts of pore formers, 5-19 parts of sintering aids, and 5-35 parts of powder dispersants, wherein the average particle sizes of the aggregates and/or pore formers in each group of ceramic powders are different; The aggregate is a material used to form a porous ceramic matrix skeleton after sintering, including at least one of kaolin, diatomaceous earth, alumina, silicon nitride, silicon carbide, quartz sand, glass sand, clay, feldspar powder, fused quartz, cordierite, and mullite; The pore-forming agent is a material that vaporizes and evaporates during sintering to form micropores in the porous ceramic matrix, including at least one of graphite, starch, wood powder, flour, bean powder, polystyrene microspheres, polymethyl methacrylate microspheres, sucrose, and fiber; The sintering aid is a material used to bond aggregates and help sinter at a suitable temperature to form a porous ceramic matrix, including at least one of boron oxide, sodium silicate, silicon oxide, potassium oxide, lithium oxide, barium oxide, magnesium oxide, calcium oxide, iron oxide, titanium oxide, zinc oxide, and zirconium oxide; The powder dispersant is a material used to promote uniform dispersion of aggregates to prevent precipitation and accumulation, including at least one of paraffin, beeswax, boric acid, oleic acid, stearic acid, polyethylene, polypropylene, polyvinyl acetate, polyvinyl acetal, ethylene-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate copolymer resin, perchlorethylene resin, polyacrylate, and polyamide; The aggregates, pore formers, sintering aids and powder dispersants weighed in several groups are fully mixed in groups to obtain several groups of ceramic powders; (2) Preparation of tape-cast ceramic slurry: Weigh several groups of tape-cast ceramic slurry components by weight, wherein the components of each group of tape-cast ceramic slurry respectively include: 40 to 65 parts of ceramic powder of one of the several groups of ceramic powders, 30 to 50 parts of solvent, 0.1 to 3 parts of slurry dispersant, 1 to 8 parts of plasticizer, and 1 to 10 parts of binder; The solvent is a material used to convert ceramic powder into a fluid, including at least one of ethanol, isopropanol, acetone, butanone, xylene, trichloroethylene, ethyl acetate, and butyl acetate; The slurry dispersant is a material used to disperse the ceramic powder in the solvent, including at least one of oleic acid, boric acid, linseed oil, castor oil, stearic acid, and triolein; The plasticizer is a material used to improve the plasticity of the ceramic green body, including at least one of polyethylene glycol and dibutyl phthalate; The binder is a material used to improve the strength of the ceramic green body, including at least one of polymethyl acrylate, ethyl cellulose, polyethylene, polyvinyl butyral, and polyisobutylene; The ceramic powder, dispersant and solvent of several groups are weighed and fully mixed and ball-milled respectively, and then the plasticizer and binder are added respectively, and then fully mixed and ball-milled to obtain several groups of tape-cast ceramic slurries; (3) Preparation of ceramic green body: The plurality of groups of tape-cast ceramic slurries are respectively made into a plurality of thin-sheet ceramic green embryos by tape-casting process, and the plurality of groups of ceramic green embryos are respectively cut into a plurality of ceramic green embryos; (4) Preparation of multi-layer porous ceramic matrix: Select a plurality of ceramic green sheets from different groups and/or different sheets from the same group, stack them up and down in the order of the average particle size of the aggregate and/or pore-forming agent contained in each ceramic green sheet, press them into a whole, and then send them into a furnace for debinding and sintering. After sintering, take them out and cut them into a desired shape, so as to obtain a multi-layer porous ceramic matrix having a plurality of ceramic sheets and vesicular micropores uniformly distributed inside, wherein a piece of the ceramic green sheet constitutes a layer of the ceramic sheet after sintering. The method for preparing a multi-layer porous ceramic matrix according to claim 1 is characterized in that, when preparing the multi-layer porous ceramic matrix, several groups of ceramic green embryos and 1 to several ceramic green embryos in each group are selected, and the groups of ceramic green embryos are stacked from bottom to top in sequence and pressed into one body in the order that the average particle size of the aggregate and/or pore-forming agent contained in each group of ceramic green embryos changes alternately or changes gradually from large to small, so that after debinding and sintering, the multi-layer porous ceramic matrix having several levels of ceramic sheets and each level having 1 to several layers of ceramic sheets is obtained, the average pore size of the micropores in the ceramic sheets of the same level and different layers is the same, the average pore size of the micropores in the ceramic sheets of different levels is different, and the average pore size of the micropores in the ceramic sheets of the several levels of ceramic sheets in the order from bottom to top has a regularity that the average pore size of the micropores in each level of the ceramic sheets changes alternately or changes gradually from large to small. The method for preparing a multi-layer porous ceramic matrix according to claim 1 is characterized in that when preparing each group of the ceramic powder, the components of the ceramic powder weighed in parts by weight include: 35 to 55 parts of the aggregate, 25 to 30 parts of the pore former, 15 to 19 parts of the sintering aid, and 5 to 10 parts of the powder dispersant. The method for preparing a multi-layer porous ceramic matrix according to claim 1 is characterized in that when preparing each group of the tape-cast ceramic slurry, the components of the tape-cast ceramic slurry weighed in parts by weight include: 45 to 55 parts of ceramic powder from one of the several groups of ceramic powders, 35 to 45 parts of solvent, 0.1 to 1 part of slurry dispersant, 1 to 5 parts of plasticizer, and 3 to 8 parts of binder. The method for preparing a multi-layer porous ceramic matrix according to claim 1 is characterized in that the average particle size of the aggregate is 5 to 100 um, or 5 to 50 um, or 10 to 30 um. The method for preparing a multi-layer porous ceramic substrate according to claim 1 is characterized in that the average particle size of the pore-forming agent is 5 to 100 um, or 15 to 80 um, or 25 to 60 um. The method for preparing a multi-layer porous ceramic substrate according to claim 1 is characterized in that when preparing the ceramic green body, a tape casting process is used to make each piece of the ceramic green body have a thickness of 0.1 to 0.6 mm, or 0.1 to 0.3 mm, or 0.25 to 0.45 mm, or 0.3 to 0.6 mm. The method for preparing a multi-layer porous ceramic substrate according to claim 1 is characterized in that the average pore size of the micropores of each ceramic layer of the multi-layer porous ceramic substrate is 10 to 50 um, or 15 to 45 um, or 20 to 40 um. The method for preparing a multi-layer porous ceramic substrate according to claim 1 is characterized in that the porosity of the micropores of each ceramic layer of the multi-layer porous ceramic substrate is 40%-65%, or 45-60%, or 48-56%. The method for preparing a multi-layer porous ceramic substrate according to claim 1 is characterized in that the thickness of each ceramic layer of the multi-layer porous ceramic substrate is 0.1 to 0.5 mm, or 0.1 to 0.25 mm, or 0.2 to 0.4 mm, or 0.25 to 0.5 mm. The method for preparing a multi-layer porous ceramic matrix according to claim 2 is characterized in that when preparing the multi-layer porous ceramic matrix, several groups of ceramic green embryos and one ceramic green embryo in each group are selected, and the groups of ceramic green embryos are stacked from bottom to top in order of the average particle size of the aggregate and/or pore-forming agent contained in each group of ceramic green embryos from large to small, and then pressed into one body, so that after debinding and sintering, the multi-layer porous ceramic matrix having several levels of ceramic sheets and one ceramic sheet in each level is obtained. The method for preparing a multi-layer porous ceramic substrate according to claim 11 is characterized in that when preparing the multi-layer porous ceramic substrate, 4 to 10 groups of the ceramic green bodies are selected, and the number of ceramic layers of the porous ceramic substrate obtained is 4 to 10 levels and the number of layers is 4 to 10. The method for preparing a multi-layer porous ceramic substrate according to claim 11 is characterized in that when preparing the multi-layer porous ceramic substrate, 4 to 6 groups of the ceramic green sheets are selected, and the number of ceramic layers of the porous ceramic substrate obtained is 4 to 6 levels and the number of layers is 4 to 6. The method for preparing a multi-layer porous ceramic substrate according to claim 11 is characterized in that when preparing the multi-layer porous ceramic substrate, 4 groups, i.e., 4 pieces of the ceramic green body are selected, wherein, in the order of stacking from bottom to top, the weight parts of the aggregate contained in the first ceramic green body are 40 to 46 parts, the average particle size of the aggregate is 70 to 75 um, the weight parts of the pore former are 25 to 28 parts, and the average particle size of the pore former is 40 to 50 um; the weight parts of the aggregate contained in the second ceramic green body are 45 to 50 parts, the average particle size of the aggregate is 40 ～60um, the weight of the pore former is 20-25 parts, and the average particle size of the pore former is 40-50um; the weight of the aggregate contained in the third ceramic green body is 40-48 parts, the average particle size of the aggregate is 15-30um, the weight of the pore former is 25-30 parts, and the average particle size of the pore former is 35-40um; the weight of the aggregate contained in the fourth ceramic green body is 35-45 parts, the average particle size of the aggregate is 10-20um, the weight of the pore former is 25-30 parts, and the average particle size of the pore former is 35-40um. The method for preparing a multi-layer porous ceramic substrate according to claim 11 is characterized in that, when preparing the multi-layer porous ceramic substrate, 4 groups, i.e., 4 pieces of the ceramic green embryos are selected to obtain 4 ceramic layers of the porous ceramic substrate, wherein, in the order of stacking from bottom to top, the pore size of the micropores in the first ceramic layer is 40 to 50 um, the pore size of the micropores in the second ceramic layer is 30 to 40 um, the pore size of the micropores in the third ceramic layer is 20 to 30 um, and the pore size of the micropores in the fourth ceramic layer is 10 to 20 um. The method for preparing a multi-layer porous ceramic matrix according to claim 2 is characterized in that when preparing the multi-layer porous ceramic matrix, several groups of ceramic green embryos and two ceramic green embryos in each group are selected, and the groups of ceramic green embryos are stacked from bottom to top in order of the average particle size of the aggregate and/or pore-forming agent contained in each group of ceramic green embryos from large to small, and then pressed into one body, so that after debinding and sintering, the multi-layer porous ceramic matrix having several levels of ceramic sheets and two ceramic sheets in each level is obtained. The method for preparing a multi-layer porous ceramic matrix according to claim 16 is characterized in that when preparing the multi-layer porous ceramic matrix, the number of groups of the ceramic green body is selected to be 2 to 5 groups, the level of the multi-layer porous ceramic matrix obtained is 2 to 5 levels, and the number of ceramic layers is twice the level. The method for preparing a multi-layer porous ceramic matrix according to claim 16 is characterized in that when preparing the multi-layer porous ceramic matrix, the number of groups of the ceramic green bodies is selected to be 3 or 4 groups, the number of levels of the porous ceramic matrix obtained is 3 or 4, and the number of ceramic layers is 6 or 8. The method for preparing a multi-layer porous ceramic matrix according to claim 16 is characterized in that when preparing the multi-layer porous ceramic matrix, the number of groups of the ceramic green embryos is selected to be 3, wherein, in the order of stacking from bottom to top, the weight parts of aggregate contained in the first group of ceramic green embryos are 40 to 46 parts, the average particle size of the aggregate is 60 to 75 um, the weight parts of the pore former are 25 to 30 parts, and the average particle size of the pore former is 40 to 50 um; the weight parts of aggregate contained in the second group of ceramic green embryos are 40 to 48 parts, the average particle size of the aggregate is 15 to 50 um, the weight parts of the pore former are 25 to 30 parts, and the average particle size of the pore former is 35 to 40 um; the weight parts of aggregate contained in the third group of ceramic green embryos are 35 to 45 parts, the average particle size of the aggregate is 10 to 20 um, the weight parts of the pore former are 25 to 30 parts, and the average particle size of the pore former is 35 to 40 um. The method for preparing a multi-layer porous ceramic matrix according to claim 16 is characterized in that, when preparing the multi-layer porous ceramic matrix, the number of groups of the ceramic green body is selected to be 3, the number of levels of ceramic layers of the porous ceramic matrix is 3, and the number of layers of ceramic layers is 6, wherein in the order of stacking from bottom to top, the pore size of the micropores in the first-level ceramic layer is 35-50um, the pore size of the micropores in the second-level ceramic layer is 20-35um, and the pore size of the micropores in the third-level ceramic layer is 10-20um. The method for preparing a multi-layer porous ceramic matrix according to claim 16 is characterized in that when preparing the multi-layer porous ceramic matrix, the number of groups of the ceramic green embryos is selected to be 4 groups, wherein, in the order of stacking from bottom to top, the weight parts of aggregate contained in the first group of ceramic green embryos are 40 to 46 parts, the average particle size of the aggregate is 70 to 75 um, the weight parts of the pore-forming agent are 25 to 28 parts, and the average particle size of the pore-forming agent is 40 to 50 um; the weight parts of aggregate contained in the second group of ceramic green embryos are 45 to 50 parts, the average particle size of the aggregate is 40 ～60um, the weight of the pore former is 20-25 parts, and the average particle size of the pore former is 40-50um; the weight of the aggregate contained in the third group of ceramic green bodies is 40-48 parts, the average particle size of the aggregate is 15-30um, the weight of the pore former is 25-30 parts, and the average particle size of the pore former is 35-40um; the weight of the aggregate contained in the fourth group of ceramic green bodies is 35-45 parts, the average particle size of the aggregate is 10-20um, the weight of the pore former is 25-30 parts, and the average particle size of the pore former is 35-40um. The method for preparing a multi-layer porous ceramic matrix according to claim 16 is characterized in that, when preparing the multi-layer porous ceramic matrix, the number of groups of the ceramic green body is selected to be 4, the number of levels of the multi-layer porous ceramic matrix obtained is 4, and the number of ceramic layers is 8, wherein in the order of stacking from bottom to top, the pore size of the micropores in the first-level ceramic layer is 40-50um, the pore size of the micropores in the second-level ceramic layer is 30-40um, the pore size of the micropores in the third-level ceramic layer is 20-30um, and the pore size of the micropores in the fourth-level ceramic layer is 10-20um. A method for preparing a multi-layer porous ceramic atomization core, characterized in that, first, a multi-layer porous ceramic substrate is prepared according to the method for preparing a multi-layer porous ceramic substrate according to any one of claims 1 to 22, and then a metal slurry is prepared, and one of the upper and lower surfaces of the multi-layer porous ceramic substrate is selected as an atomization surface and the other surface is selected as a liquid guide surface, the metal slurry is printed on both ends of the atomization surface by screen printing and sintered to obtain an electrode layer, and finally a metal heating layer is obtained on the atomization surface by a metal sputtering coating process or by a process of screen printing another metal slurry and then sintering, and the metal heating layer covers the electrode layer, so as to obtain a multi-layer porous ceramic atomization core. The method for preparing a multi-layer porous ceramic atomization core according to claim 23 is characterized in that, among the upper and lower surfaces of the multi-layer porous ceramic substrate, one side with a smaller pore size of the micropores is selected as the atomization surface, and the other side is used as the liquid guide surface, and a layer of metal heating layer is obtained on the atomization surface by a metal sputtering coating process or by a screen printing metal slurry followed by sintering, thereby obtaining a multi-layer porous ceramic atomization core.