Method for manufacturing multilayer ceramic, multilayer ceramic and applications thereof

Abstract

The application relates to a multilayer ceramic preparation method, a multilayer ceramic and application thereof. The multilayer ceramic preparation method comprises the following steps: heating and mixing 20-50 parts of ceramic powder and 9-60 parts of wax material to obtain slurry; using the slurry to prepare ceramic film materials through heating flow casting; stacking the ceramic film materials and performing hot pressing to obtain a multilayer ceramic green body; and sintering the multilayer ceramic green body. In the multilayer ceramic preparation method, the slurry is prepared by using the wax material. In the process of stacking the ceramic film materials and performing hot pressing, the ceramic film materials can be fused into an integral whole under the action of hot pressing, and it is not necessary to use an adhesive or set an additional bonding layer to bond the ceramic film materials, so that the product is not prone to cracking in the subsequent sintering process for preparing the multilayer ceramic.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of porous ceramics, in particular to a preparation method of multilayer ceramics, multilayer ceramics and application thereof. BACKGROUND

[0002] The tape casting method refers to adding solvent and other components into ceramic powder to obtain a uniform and stable slurry, and then a film with a required thickness is prepared on a casting machine. This method has been widely applied in the forming process of ceramic materials due to its simple equipment, continuous operation, high production efficiency, high automation level, stable process, high repeatability of the performance of the formed body and high consistency of the size, and uniform performance of the body.

[0003] When producing multilayer ceramic products, a single layer of ceramic film material is first prepared by the tape casting method, and then multiple ceramic film materials are stacked and sintered. In the traditional preparation of multilayer ceramics, the multiple ceramic film materials are stacked and sintered after being bonded. During the sintering process, the product is prone to cracking. SUMMARY

[0004] Therefore, it is necessary to provide a preparation method of multilayer ceramics, multilayer ceramics and application thereof. The preparation method of multilayer ceramics can prevent the product from cracking during sintering of the stacked ceramic film materials.

[0005] In a first aspect, the present application provides a preparation method of multilayer ceramics, comprising:

[0006] heating and mixing 20-50 parts by mass of ceramic powder and 9-60 parts of wax material to obtain a slurry;

[0007] preparing a ceramic film material by heating tape casting using the slurry;

[0008] stacking multiple ceramic film materials and hot pressing to obtain a multilayer ceramic green body;

[0009] sintering the multilayer ceramic green body.

[0010] In some embodiments, the temperature of the heating tape casting is 50-100℃.

[0011] In some embodiments, the pressure of the hot pressing is 1-20 MPa.

[0012] In some embodiments, the temperature of the hot pressing is 50-100℃.

[0013] In some embodiments, the temperature of the heating mixing is 50-100℃.

[0014] In some embodiments, the ceramic powder comprises at least one of alumina, silica, silicon carbide, silicon nitride, kaolin, diatomite, cordierite, apatite, and feldspar.

[0015] In some embodiments, the ceramic powder has a D50 of 20 μm to 200 μm.

[0016] In some embodiments, the wax material comprises at least one of paraffin wax, beeswax, and palm wax.

[0017] In some embodiments, the slurry further comprises a low-melting glass powder in a mass fraction of 5 parts to 20 parts.

[0018] In some embodiments, the slurry further comprises a plasticizer in a mass fraction of 0.5 parts to 5 parts.

[0019] In some embodiments, the slurry further comprises a dispersant in a mass fraction of 0.5 parts to 5 parts.

[0020] In some embodiments, the slurry further comprises a pore-forming agent in a mass fraction of 5 parts to 20 parts.

[0021] In some embodiments, the low-melting glass powder has a melting temperature of 300 °C to 1000 °C.

[0022] In some embodiments, the low-melting glass powder has a D50 of 10 μm to 100 μm.

[0023] In some embodiments, the plasticizer comprises at least one of dibutyl phthalate, polyalkyl glycol, triethylene glycol, glycerol, phosphate, phosphoric acid complex salt, allyl sulfonic acid, acrylic copolymer, and ethylene-vinyl acetate copolymer.

[0024] In some embodiments, the dispersant comprises at least one of oleic acid, fatty acid, fish oil, palm oil, castor oil, phosphatidic acid, octadiene, oil-soluble sulfonate, tributyl phosphate, triethanolamine, and glyceryl trioleate.

[0025] In some embodiments, the pore-forming agent comprises at least one of ammonium carbonate, ammonium bicarbonate, ammonium phosphate, carbon powder, starch, fiber, urea, polyvinyl chloride, polyvinyl alcohol, polymethyl methacrylate, polyvinyl butyral, polystyrene particles, and carboxymethyl cellulose.

[0026] In some embodiments, the pore-forming agent has a D50 of 20 μm to 150 μm.

[0027] In a second aspect, the present application provides a multilayer ceramic prepared by the method of any one of the above.

[0028] In a third aspect, the present application provides a ceramic atomization core, comprising the multilayer ceramic.

[0029] In a fourth aspect, the present application provides an electronic atomizer, comprising the ceramic atomization core.

[0030] In the preparation method of the multilayer ceramic, the slurry is prepared by using the wax material. The wax material is solid at room temperature and can be melted into liquid state after being heated to a certain temperature. The ceramic powder and the pore-forming agent can be dispersed in the liquid wax material to obtain the slurry and prepare the ceramic film material. In the process of stacking the plurality of ceramic film materials and heat pressing, the wax material can be softened by heat, and the plurality of ceramic film materials can be fused into a whole under the action of heat pressing, without the need to use an adhesive or set an additional bonding layer to bond the plurality of ceramic film materials, so that the product is less likely to crack in the subsequent sintering process for preparing the multilayer ceramic. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The equipment structure schematic diagram for producing the ceramic film material by the casting method is provided for the embodiment 1 of the present application;

[0032] Figure 2 The exploded view of the structure of the multilayer ceramic sample is provided for the embodiment 1 of the present application;

[0033] Figure 3 The SEM diagram of the microstructure of the multilayer ceramic sample is provided for the embodiment 1 of the present application. DETAILED DESCRIPTION

[0034] In order to make the above objectives, features and advantages of the present application more apparent and comprehensible, the specific embodiments of the present application are described in detail below in conjunction with the drawings. In the following description, a large number of specific details are set forth in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0035] 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 the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0036] An embodiment of the present application provides a preparation method of a multilayer ceramic, comprising:

[0037] The ceramic powder with a mass fraction of 20 parts to 50 parts and the wax material with a mass fraction of 9 parts to 60 parts are mixed to obtain a slurry;

[0038] Preparation of ceramic membrane material by heating flow casting using slurry;

[0039] Stacking and hot-pressing of multiple ceramic membrane materials to obtain a multi-layer ceramic green body;

[0040] Sintering of the multi-layer ceramic green body. In the above method for preparing a multi-layer ceramic, a wax material is used to prepare the slurry. The wax material is solid at room temperature and can be melted into a liquid state when heated to a certain temperature. The ceramic powder and pore-forming agent can be dispersed in the liquid wax material to obtain the slurry and prepare the ceramic membrane material. During the stacking and hot-pressing of multiple ceramic membrane materials, the wax material softens under heat, and the multiple ceramic membrane materials can be fused into a whole under the action of hot-pressing, without the need for using an adhesive or setting an additional bonding layer to bond the multiple ceramic membrane materials. The product is less likely to crack during the subsequent sintering process to prepare a multi-layer ceramic.

[0041] Optionally, the mass fraction of the ceramic powder is 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, 48 parts, or 50 parts. Optionally, the mass fraction of the wax material is 9 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, 48 parts, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts, or 60 parts.

[0042] In some embodiments, the temperature for heating flow casting is 50-100℃. Optionally, the temperature for heating flow casting is 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, or 100℃.

[0043] In some embodiments, the pressure for hot-pressing is 1-20 MPa. Within this pressure range for hot-pressing, the multiple ceramic membrane materials can be fused together under the action of hot-pressing. Optionally, the pressure for hot-pressing is 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15 MPa, 16 MPa, 17 MPa, 18 MPa, 19 MPa, or 20 MPa.

[0044] In some embodiments, the temperature for hot-pressing is 50-100℃. Within this temperature range for hot-pressing, the multiple ceramic membrane materials can be fused together under the action of hot-pressing. Optionally, the temperature for hot-pressing is 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, or 100℃.

[0045] In some embodiments, the temperature of the heated mixing is 50-100℃. Optionally, the temperature of the heated mixing is 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃.

[0046] In some embodiments, the heated mixing is a heated stirring mixing.

[0047] In some embodiments, the time of the heated stirring mixing is 0.5-10h. Optionally, the time of the heated stirring is 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h or 10h.

[0048] In some embodiments, the ceramic powder comprises at least one of alumina, silica, silicon carbide, silicon nitride, kaolin, diatomite, cordierite, apatite, feldspar.

[0049] In some embodiments, the D50 of the ceramic powder is 20-200μm. Within the range of the D50 of the ceramic powder, the dispersion effect of the ceramic powder is better. Optionally, the D50 of the ceramic powder is 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, 105μm, 110μm, 115μm, 120μm, 125μm, 130μm, 135μm, 140μm, 145μm, 150μm, 155μm, 160μm, 165μm, 170μm, 175μm, 180μm, 185μm, 190μm, 195μm or 200μm.

[0050] In some embodiments, the wax material comprises at least one of paraffin wax, beeswax, palm wax.

[0051] In some embodiments, the slurry further comprises low-melting-point glass powder in a mass fraction of 5-20 parts. The low-melting-point glass powder, as a sintering aid, can make the sintering of the multilayer ceramic more densified. Within the range of the mass fraction of the low-melting-point glass powder, the improvement effect of the low-melting-point glass powder on the densification of the sintering of the multilayer ceramic is better. Optionally, the mass fraction of the low-melting-point glass powder is 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, 10 parts, 10.5 parts, 11 parts, 11.5 parts, 12 parts, 12.5 parts, 13 parts, 13.5 parts, 14 parts, 14.5 parts, 15 parts, 15.5 parts, 16 parts, 16.5 parts, 17 parts, 17.5 parts, 18 parts, 18.5 parts, 19 parts, 19.5 parts or 20 parts.

[0052] In some embodiments, the slurry further comprises a plasticizer in a mass fraction of 0.5 parts to 5 parts. The addition of the plasticizer can enhance the plasticity of the ceramic membrane material, and the film-forming effect is better when the ceramic membrane material is prepared. Within the mass fraction range of the plasticizer, the improvement effect on the plasticity of the ceramic membrane material is better. Alternatively, the mass fraction of the plasticizer is 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, or 5 parts.

[0053] In some embodiments, the slurry further comprises a dispersant in a mass fraction of 0.5 parts to 5 parts. The dispersant can improve the dispersion effect of the ceramic powder in the wax material dispersion medium, and within the mass fraction range of the dispersant, the improvement effect of the dispersant on the dispersion effect of the ceramic powder is better. Alternatively, the mass fraction of the dispersant is in the range of 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, or 5 parts.

[0054] In some embodiments, the slurry further comprises a pore-forming agent in a mass fraction of 5 parts to 20 parts. The addition of the pore-forming agent can prepare a porous ceramic, and within the mass fraction range of the pore-forming agent, the ceramic pore-forming effect is better. Alternatively, the mass fraction of the pore-forming agent is 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, or 20 parts.

[0055] In some embodiments, the melting temperature of the low-melting-point glass powder is 300°C to 1000°C. Within the melting temperature range of the low-melting-point glass powder, the low-melting-point glass powder as a sintering aid has a better improvement effect on the densification of the sintering of the multilayer ceramic. Alternatively, the melting temperature of the low-melting-point glass powder is 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, or 1000°C.

[0056] In some embodiments, the D50 of the low-melting-point glass powder is 10 μm to 100 μm. Within the D50 range of the low-melting-point glass powder, the low-melting-point glass powder as a sintering aid has a better improvement effect on the densification of the sintering of the multilayer ceramic. Alternatively, the D50 of the low-melting-point glass powder is 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, or 100 μm.

[0057] In some embodiments, the plasticizer includes at least one of dibutyl phthalate, polyalkyl glycol, triethylene glycol, glycerol, phosphate, phosphonate, allyl sulfonic acid, acrylic copolymer, ethylene-vinyl acetate copolymer.

[0058] In some embodiments, the dispersant includes at least one of oleic acid, fatty acid, fish oil, palm oil, castor oil, phosphatidic acid, octadiene, oil-soluble sulfonate, tributyl phosphate, triethanolamine, triolein.

[0059] In some embodiments, the pore-forming agent includes at least one of ammonium carbonate, ammonium bicarbonate, ammonium phosphate, carbon powder, starch, fiber, urea, polyvinyl chloride, polyvinyl alcohol, polymethyl methacrylate, polyvinyl butyral, polystyrene particles, carboxymethyl cellulose.

[0060] In some embodiments, the pore-forming agent has a D50 of 20 μm to 150 μm. Within the D50 range of the pore-forming agent, pores of a pore size can be formed in the multilayer ceramic. Alternatively, the pore-forming agent has a D50 of 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm, or 150 μm.

[0061] In some embodiments, the slurry includes the following components in mass parts: 20 parts to 50 parts of the ceramic powder, 5 parts to 20 parts of the pore-forming agent, 9 parts to 60 parts of the wax material, 5 parts to 20 parts of the low-melting glass powder, 0.5 parts to 5 parts of the plasticizer, and 0.5 parts to 5 parts of the dispersant.

[0062] In some embodiments, the slurry includes the following components in mass percentage: 20% to 50% of the ceramic powder, 5% to 20% of the pore-forming agent, 9% to 60% of the wax material, 5% to 20% of the low-melting glass powder, 0.5% to 5% of the plasticizer, and 0.5% to 5% of the dispersant.

[0063] In some embodiments, the slurry includes the following components in mass percentage: 20% to 50% of the ceramic powder, 5% to 20% of the pore-forming agent, 9% to 60% of the wax material, 5% to 20% of the low-melting glass powder, 0.5% to 5% of the plasticizer, and 0.5% to 5% of the dispersant.

[0064] In some embodiments, the sintering of the multilayer ceramic green body comprises a first sintering, a second sintering and a third sintering successively performed in sequence; the first sintering is heating to 180-250°C at a heating rate of 1-3°C / min and holding for 5-12h, the second sintering is heating to 300-500°C at a heating rate of 0.5-2°C / min and holding for 10-20h, and the third sintering is heating to 600-800°C at a heating rate of 1-3°C / min and holding for 5-12h. Optionally, the heating rate of the first sintering is 1°C / min, 2°C / min or 3°C / min, the holding temperature of the first sintering is 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C or 250°C, and the holding time of the first sintering is 5h, 6h, 7h, 8h, 9h, 10h, 11h or 12h. Optionally, the heating rate of the second sintering is 0.5°C / min, 1°C / min, 1.5°C / min or 2°C / min, the holding temperature of the second sintering is 300°C, 320°C, 340°C, 360°C, 380°C, 400°C, 420°C, 440°C, 460°C, 480°C or 500°C, and the holding time of the second sintering is 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h or 20h. Optionally, the heating rate of the third sintering is 1°C / min, 2°C / min or 3°C / min, the holding temperature of the third sintering is 600°C, 620°C, 640°C, 660°C, 680°C, 700°C, 720°C, 740°C, 760°C, 780°C or 800°C, and the holding time of the third sintering is 5h, 6h, 7h, 8h, 9h, 10h, 11h or 12h.

[0065] In some embodiments, the method for preparing the multilayer ceramic comprises the following steps:

[0066] (1) mixing and heating-stirring 20-50 parts by mass of ceramic powder, 5-20 parts by mass of pore-forming agent, 9-60 parts by mass of wax material, 5-20 parts by mass of low-melting-point glass powder, 0.5-5 parts by mass of plasticizer and 0.5-5 parts by mass of dispersant to obtain a slurry, the heating-stirring temperature is 75-100°C, and the heating-stirring time is 0.5-10h;

[0067] (2) preparing ceramic film materials by heating-casting the slurry, the heating-casting temperature is 50-100°C;

[0068] (3) stacking a plurality of ceramic film materials and performing hot pressing to obtain a multilayer ceramic green body, the hot pressing temperature is 50-100°C, and the hot pressing pressure is 1-20MPa;

[0069] (4) The multilayer ceramic green body is continuously subjected to the first sintering, the second sintering and the third sintering in sequence; the first sintering is to heat to 180℃~250℃ at a heating rate of 1℃ / min~3℃ / min and hold for 5h~12h, the second sintering is to heat to 300℃~500℃ at a heating rate of 0.5℃ / min~2℃ / min and hold for 10h~20h, and the third sintering is to heat to 600℃~800℃ at a heating rate of 1℃ / min~3℃ / min and hold for 5h~12h.

[0070] In some embodiments, the preparation method of multilayer ceramics includes the following steps:

[0071] (1) Mix 20% to 50% ceramic powder, 5% to 20% pore-forming agent, 9% to 60% wax material, 5% to 20% low melting point glass powder, 0.5% to 5% plasticizer and 0.5% to 5% dispersant by mass and heat and stir to obtain a slurry. The heating and stirring temperature is 75℃ to 100℃ and the heating and stirring time is 0.5h to 10h.

[0072] (2) Prepare ceramic film by heating and casting the slurry at a temperature of 50℃~100℃;

[0073] (3) Multiple ceramic films are stacked and hot-pressed together. The hot-pressing temperature is 50℃~100℃ and the hot-pressing pressure is 1MPa~20MPa to obtain a multi-layer ceramic green body.

[0074] (4) The multilayer ceramic green body is continuously subjected to the first sintering, the second sintering and the third sintering in sequence; the first sintering is to heat to 180℃~250℃ at a heating rate of 1℃ / min~3℃ / min and hold for 5h~12h, the second sintering is to heat to 300℃~500℃ at a heating rate of 0.5℃ / min~2℃ / min and hold for 10h~20h, and the third sintering is to heat to 600℃~800℃ at a heating rate of 1℃ / min~3℃ / min and hold for 5h~12h.

[0075] Another embodiment of this application provides a multilayer ceramic, which is prepared by any of the above-described methods for preparing multilayer ceramics.

[0076] Another embodiment of this application provides a ceramic atomizing core, comprising the above-described multilayer ceramic.

[0077] In some embodiments, the ceramic atomizing core further includes a heating element disposed inside the multilayer ceramic.

[0078] In some embodiments, the heating element includes at least one of a heating wire, a heating mesh, a heating plate, and a heating rod.

[0079] An electronic atomizer is provided in a further embodiment of the application, comprising the ceramic atomizing core described above.

[0080] The following are specific embodiments

[0081] Embodiment 1

[0082] Preparation of multilayer porous ceramics

[0083] (1) Mix the following raw materials in the following mass percentages and heat and stir in an internal mixer: 30% alumina powder, 20% low-melting-point glass powder, 15% starch, 3% ethylene-vinyl acetate copolymer powder, 30% paraffin, and 2% oleic acid. Among them, the D50 of the alumina powder is 50-100 μm, the melting temperature of the low-melting-point glass powder is 450-700 °C, the D50 of the low-melting-point glass powder is 30-50 μm, and the D50 of the starch is 50-80 μm. The temperature of the internal mixer is set to 80 °C, and the stirring time is 3.5 h to obtain a mixed slurry.

[0084] (2) Refer to Figure 1 Transfer the mixed slurry to a casting machine bin with heating and stirring functions, set the heating temperature to 80 °C, and the stirring speed to 50 r / min to maintain the fluidity of the slurry. Set the casting thickness to 1 mm, and cast the first ceramic film material. After the film material is dried, it is sealed and stored.

[0085] (3) Replace the alumina powder in step (1) with a zirconia and quartz composite powder of the same particle size distribution, with the mass percentage of zirconia in the composite powder being 50%. Replace the starch with a D50 of 50-80 μm with starch with a D50 of 0.1 mm, and keep the rest of the raw materials unchanged. Repeat steps (1) and (2) after preparing the slurry, and cast the second ceramic film material.

[0086] (4) Replace the alumina powder in step (1) with a quartz powder of the same particle size distribution, and replace the starch with a D50 of 50-80 μm with starch with a D50 of 0.5 mm. Keep the rest of the raw materials unchanged. Repeat steps (1) and (2) after preparing the slurry, and cast the third ceramic film material.

[0087] (5) Make through holes in the first ceramic film material and the second ceramic film material, respectively, and pre-place a metal heating mesh on the outer surface of the third ceramic film material. Thread the heating mesh wires through the through holes of the first ceramic film material and the second ceramic film material, and heat-press the first ceramic film material, the second ceramic film material, and the third ceramic film material stacked from bottom to top at a temperature of 80 °C and a pressure of 10 MPa to form a whole, as shown in the structural diagram Figure 2 Cut the multilayer ceramic green body after heat pressing into individual samples according to the required size.

[0088] (6) The single sample is heated to 200°C at a rate of 1°C / min and kept for 6h, heated to 400°C at a rate of 0.5°C / min and kept for 12h, and heated to 650°C at a rate of 1°C / min and kept for 6h to complete sintering, and the micro-morphology of the sample is as shown in Figure 3

[0089] Example 2

[0090] Preparation of multilayer ceramic

[0091] (1) The raw materials in the following mass percentages are mixed and heated and stirred in an internal mixer: 50% of alumina powder and 50% of paraffin wax. The D50 of the alumina powder is 50-100 μm. The temperature of the internal mixer is set to 80°C, and the stirring time is 3.5h to obtain a mixed slurry.

[0092] (2) The mixed slurry is transferred to a casting machine bin with heating and stirring functions, the heating temperature is set to 80°C, the stirring speed is 50r / min, the fluidity of the slurry is maintained, the casting thickness is set to 1mm, and the first ceramic film material is cast. After the film material is dried, it is sealed and stored.

[0093] (3) The alumina powder in step (1) is replaced with zirconia and quartz composite powder with the same particle size distribution, and the mass percentage of zirconia in the composite powder is 50%. After the slurry is prepared, steps (1) and (2) are repeated, and the second ceramic film material is cast.

[0094] (4) The alumina powder in step (1) is replaced with quartz powder with the same particle size distribution, and the slurry is prepared. After repeating steps (1) and (2), the third ceramic film material is cast.

[0095] (5) Through holes are punched in the first ceramic film material and the second ceramic film material, and a metal heating net is placed on the outer surface of the third ceramic film material. The lead wire of the heating net is passed through the through holes of the first ceramic film material and the second ceramic film material, and the first ceramic film material, the second ceramic film material and the third ceramic film material are stacked from bottom to top and hot-pressed to form a whole at a temperature of 80°C and a pressure of 10MPa. The multilayer ceramic green body after hot pressing is cut into individual samples according to the required size.

[0096] (6) The single sample is heated to 200°C at a rate of 1°C / min and kept for 6h, heated to 400°C at a rate of 0.5°C / min and kept for 12h, and heated to 650°C at a rate of 1°C / min and kept for 6h to complete sintering.

[0097] Example 3

[0098] Preparation of multilayer porous ceramic

[0099] ​(1) Mix the following raw materials in mass percentage and heat and stir in an internal mixer: 30% silicon carbide powder, 20% low-melting-point glass powder, 15% ammonium bicarbonate, 3% ethylene-vinyl acetate copolymer powder, 30% paraffin wax, and 2% oleic acid. The D50 of the silicon carbide powder is 50-100 μm, the melting temperature of the low-melting-point glass powder is 450-700 °C, the D50 of the low-melting-point glass powder is 30-50 μm, and the D50 of the starch is 50-80 μm. The temperature of the internal mixer is set to 80 °C, and the stirring time is 3.5 h to obtain a mixed slurry.

[0100] (2) Transfer the mixed slurry to a casting machine bin with heating and stirring functions, set the heating temperature to 80 °C, and the stirring speed to 50 r / min to maintain the flowability of the slurry. Set the casting thickness to 1 mm, and cast the first ceramic film material. After the film material is dried, it is sealed and stored.

[0101] (3) Replace the silicon carbide powder in step (1) with a composite powder of silicon carbide and quartz having the same particle size distribution, with the mass percentage of silicon carbide in the composite powder being 50%. Replace the ammonium bicarbonate with a D50 of 50-80 μm with ammonium bicarbonate with a D50 of 0.1 mm. The remaining raw materials remain unchanged. Repeat steps (1) and (2) after preparing the slurry, and cast the second ceramic film material.

[0102] (4) Replace the silicon carbide powder in step (1) with a quartz powder having the same particle size distribution, and replace the ammonium bicarbonate with a D50 of 50-80 μm with ammonium bicarbonate with a D50 of 0.5 mm. The remaining raw materials remain unchanged. Repeat steps (1) and (2) after preparing the slurry, and cast the third ceramic film material.

[0103] (5) Make through holes in the first and second ceramic film materials, and pre- place a metal heating mesh on the outer surface of the third ceramic film material. Thread the leads of the heating mesh through the through holes in the first and second ceramic film materials, and heat-press the first, second, and third ceramic film materials stacked from bottom to top at a temperature of 80 °C and a pressure of 10 MPa to form a whole. Cut the heat-pressed multilayer ceramic green body into individual samples according to the required size.

[0104] (6) Heat the individual samples to 200 °C at a rate of 1 °C / min, and hold at this temperature for 6 h. Heat to 400 °C at a rate of 0.5 °C / min, and hold at this temperature for 12 h. Heat to 650 °C at a rate of 1 °C / min, and hold at this temperature for 6 h to complete sintering.

[0105] Example 4

[0106] Preparation of multilayer porous ceramic

[0107] (1) Mix and heat stir the following raw materials in a mass percentage in an internal mixer: 15% silicon nitride powder, 20% low-melting-point glass powder, 22% ammonium bicarbonate, 3% ethylene-vinyl acetate copolymer powder, 35% paraffin wax, and 5% oleic acid. Among them, the D50 of the silicon carbide powder is 50-100 μm, the melting temperature of the low-melting-point glass powder is 450-700 °C, the D50 of the low-melting-point glass powder is 30-50 μm, and the D50 of the starch is 50-80 μm. The temperature of the internal mixer is set to 80 °C, and the stirring time is 3.5 h to obtain a mixed slurry.

[0108] (2) Transfer the mixed slurry to a casting machine bin with heating and stirring functions, set the heating temperature to 80 °C, and the stirring speed to 50 r / min to maintain the fluidity of the slurry. Set the casting thickness to 1 mm, and cast the first ceramic film material. After the film material is dried, it is sealed and stored.

[0109] (3) Replace the silicon nitride powder in step (1) with a silicon nitride and quartz composite powder of the same particle size distribution, with the mass percentage of silicon carbide in the composite powder being 50%. Replace the ammonium bicarbonate with a D50 of 50-80 μm with ammonium bicarbonate with a D50 of 0.1 mm. The remaining raw materials remain unchanged. Repeat steps (1) and (2) after preparing the slurry, and cast the second ceramic film material.

[0110] (4) Replace the silicon nitride powder in step (1) with a quartz powder of the same particle size distribution, and replace the ammonium bicarbonate with a D50 of 50-80 μm with ammonium bicarbonate with a D50 of 0.5 mm. The remaining raw materials remain unchanged. Repeat steps (1) and (2) after preparing the slurry, and cast the third ceramic film material.

[0111] (5) Make through holes in the first and second ceramic film materials, and pre-place a metal heating mesh on the outer surface of the third ceramic film material. Thread the heating mesh wires through the through holes of the first and second ceramic film materials, and heat press the first, second, and third ceramic film materials stacked from bottom to top under a temperature of 80 °C and a pressure of 10 MPa to form a whole. Cut the heat-pressed multilayer ceramic green body into individual samples according to the required size.

[0112] (6) Heat the individual samples to 200 °C at a rate of 1 °C / min, and hold for 6 h. Heat to 400 °C at a rate of 0.5 °C / min, and hold for 12 h. Heat to 650 °C at a rate of 1 °C / min, and hold for 6 h to complete sintering.

[0113] Comparative Example 1

[0114] Preparation of Multilayer Ceramic

[0115] (1) Mix the following raw materials in mass percentage and carry out ball milling in a ball milling tank: 50% alumina ceramic powder, 39% organic solvent, 1% castor oil as dispersant, the mass ratio of ethanol and methanol in the organic solvent is 1:1, the ball milling parameters are 400 r / min, the ball milling time is 6 h, and the mass ratio of powder to zirconium ball is 1:1. Then add 5% plasticizer and 5% binder PVB respectively in mass percentage, the plasticizer is dibutyl phthalate and PEG400 in a mass ratio of 1:1, and continue to carry out ball milling, the ball milling parameters are 400 r / min, the ball milling time is 12 h, and the slurry is obtained. After completing the ball milling, vacuum degassing is carried out to remove the bubbles in the slurry, and the vacuum degree is kept at -0.09 MPa.

[0116] (2) Transfer the above slurry to the casting machine bin, then cast at a speed of 1 mm / s, dry at a temperature of 40-50°C, and obtain a casting film.

[0117] (3) Cut the above casting film according to a certain size, then coat the binder on multiple casting films and heat to bond into a whole, and then sinter in a sintering furnace at 1100°C for 12 h, and obtain a multilayer ceramic.

[0118] Comparative Example 2

[0119] Preparation of Multilayer Porous Ceramic

[0120] (1) Mix the following raw materials in mass percentage and carry out ball milling in a ball milling tank: 20% zirconia ceramic powder, 10% alumina ceramic powder, 10% low-melting-point glass powder, 48.5% ethanol solvent, 1.5% triethanolamine as dispersant, the ball milling parameters are 400 r / min, the ball milling time is 6 h, and the mass ratio of powder to zirconium ball is 1:1. Then add 5% plasticizer and 5% binder PVB respectively in mass percentage, the plasticizer is dibutyl phthalate and PEG400 in a mass ratio of 1:1, and continue to carry out ball milling, the ball milling parameters are 400 r / min, the ball milling time is 12 h, and the slurry is obtained. After completing the ball milling, vacuum degassing is carried out to remove the bubbles in the slurry, and the vacuum degree is kept at -0.09 MPa.

[0121] (2) Transfer the above slurry to the casting machine bin, then cast at a speed of 1 mm / s, dry at a temperature of 40-50°C, and obtain a casting film.

[0122] (3) Cut the above casting film according to a certain size, then coat the binder on multiple casting films and heat to bond into a whole, and then sinter in a sintering furnace at 900°C for 12 h, and obtain a multilayer porous ceramic.

[0123] The wax material is used as the dispersion medium to prepare the slurry in Examples 1-4, the ceramic film materials are stacked to obtain the green body of the multilayer ceramic by hot pressing when the multilayer ceramic is prepared, and the sample is not easy to crack during sintering. The traditional organic solvent is used to prepare the slurry in Comparative Examples 1-2, the ceramic film materials are stacked and bonded by using the adhesive to perform sintering after bonding when the multilayer ceramic is prepared, and the sample is easy to crack during sintering. Meanwhile, a large amount of organic solvent is used in Comparative Examples 1-2, the storage and operation of the organic solvent are strictly required to avoid causing fire or other unpredictable disasters, and the environment is easy to be damaged due to the volatilization of the large amount of organic solvent.

[0124] The technical features of the above-described embodiments can be combined arbitrarily, and for the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present disclosure.

[0125] The above-described embodiments only express several implementation manners of the present application, the description is relatively specific and detailed, but it should not be understood as the limitation on the scope of the patent right of the present application. It should be pointed out that, for the ordinary skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims, and the description and the drawings can be used to explain the content of the claims.

Claims

1. A method for preparing multilayer ceramics, characterized in that, include: A slurry is prepared by heating and mixing 20 to 50 parts by weight of ceramic powder and 9 to 60 parts by weight of wax material; the wax material includes at least one of paraffin wax, beeswax and carnauba wax. Ceramic films are prepared by heating and casting using the slurry; the heating and casting temperature is 50℃~100℃. Multiple ceramic films are stacked and hot-pressed together to obtain a multilayer ceramic green body; the hot-pressing temperature is 50℃~100℃. The multilayer ceramic green body is sintered, including a first sintering, a second sintering, and a third sintering performed sequentially. The first sintering involves heating to 180℃~250℃ at a heating rate of 1℃ / min~3℃ / min and holding at that temperature for 5h~12h. The second sintering involves heating to 300℃~500℃ at a heating rate of 0.5℃ / min~2℃ / min and holding at that temperature for 10h~20h. The third sintering involves heating to 600℃~800℃ at a heating rate of 1℃ / min~3℃ / min and holding at that temperature for 5h~12h.

2. The method for preparing multilayer ceramics according to claim 1, characterized in that, The pressure for hot pressing is 1MPa~20MPa; And / or, the temperature of the heating mixture is 50°C to 100°C.

3. The method for preparing multilayer ceramics according to claim 1, characterized in that, The ceramic powder includes at least one of alumina, silicon oxide, silicon carbide, silicon nitride, kaolin, diatomite, cordierite, apatite, and feldspar. And / or, the D50 of the ceramic powder is 20µm~200µm.

4. The method for preparing multilayer ceramics according to any one of claims 1 to 3, characterized in that, The slurry also includes 5 to 20 parts by weight of low melting point glass powder; And / or, the slurry further includes 0.5 to 5 parts by weight of a plasticizer; And / or, the slurry further includes a dispersant in the form of 0.5 to 5 parts by weight; And / or, the slurry further includes 5 to 20 parts by weight of a pore-forming agent.

5. The method for preparing multilayer ceramics according to claim 4, characterized in that, The melting temperature of the low-melting-point glass powder is 300℃~1000℃; And / or, the D50 of the low melting point glass powder is 10µm~100µm; And / or, the plasticizer includes at least one of dibutyl phthalate, polyalkyl glycol, triethylene glycol, glycerol, phosphate, phosphate complex, allyl sulfonic acid, acrylic copolymer and ethylene-vinyl acetate copolymer; And / or, the dispersant includes at least one of oleic acid, fatty acid, fish oil, palm oil, castor oil, phosphatidic acid, octadiene, oil-soluble sulfonate, tributyl phosphate, triethanolamine, and trioleic acid glyceride.

6. The method for preparing multilayer ceramics according to claim 4, characterized in that, The pore-forming agent includes at least one of ammonium carbonate, ammonium bicarbonate, ammonium phosphate, carbon powder, starch, fiber, urea, polyvinyl chloride, polyvinyl alcohol, polymethyl methacrylate, polyvinyl butyral, polystyrene particles, and carboxymethyl cellulose. And / or, the D50 of the pore-forming agent is 20µm~150µm.

7. A multilayer ceramic, characterized in that, The multilayer ceramic was prepared by any one of the preparation methods described in claims 1 to 6.

8. A ceramic atomizing core, characterized in that, Including the multilayer ceramic as described in claim 7.

9. An electronic atomizer, characterized in that, Includes the ceramic atomizing core as described in claim 8.

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