Porous ceramic material for atomization, atomization core and preparation method thereof

Abstract

The present invention relates to the field of porous ceramics for atomization, and provides a porous ceramic material for atomization, an atomizer core, and a preparation method thereof. The preparation method comprises: using a jetting process to spray quartz sand into a high-temperature zone generated by an arc plasma torque, melting the surface of the quartz sand and vaporizing impurities, and then forming spherical or / and quasi-spherical quartz powder through a quenching atmosphere; weighing the prepared quartz powder, plasticizer, binder, pore-forming agent, and sintering aid according to the mass fraction requirements and mixing them, and forming a ceramic green body; heating to remove binder and sintering to obtain a porous ceramic material. The atomizer core is prepared by forming a heating circuit using the above-mentioned porous ceramic material through a sputtering coating process. The porous ceramic material prepared by this method has a large proportion of through holes, a strong liquid-conducting ability, and a ceramic matrix with good mechanical properties. The surface under the microstructure of the porous ceramic material is rounded, and there are no sharp corners or burrs on the sintered neck. The service life of the prepared atomizer core is increased by more than 100%.

Description

Technical Field

[0001] The present invention relates to the field of porous ceramics for atomization, in particular to a porous ceramic material for atomization, an atomization core and a preparation method thereof. Background Art

[0002] The atomizer core is a crucial component of an atomizer. During atomization, the atomized liquid is conducted through the capillary action of the porous ceramic, passing through the heating electrode, where the heat atomizes it. The performance of the atomizer core directly affects atomization stability, droplet size and uniformity, and atomization efficiency.

[0003] Current atomizer cores are primarily made of silicon or aluminum raw materials. After adding certain binders and pore-forming agents, they are molded and sintered to form a porous ceramic matrix, which is then combined with a heating structure to create a porous ceramic atomizer core. The ceramic raw materials used to manufacture atomizer cores are obtained through processes such as crushing, washing, drying, and screening. The particle surface has distinct tentacles and sharp corners, resulting in a poorly flat ceramic matrix. After being combined with the heating structure, the matrix has poor bonding strength with the metal heating circuit, making it easy for the heating structure to separate from the ceramic matrix, causing changes in the atomizer core resistance, affecting atomization efficiency, and seriously affecting the product experience.

[0004] With the continuous development and advancement of atomizer cores, methods for combining porous ceramics with heating structures have emerged on the market, including thick-film printing, steel sheet embedding, and sputtering coating. Atomizer cores obtained by sputtering coating on porous ceramic substrates have been continuously verified to offer advantages such as improved atomization, high-temperature resistance, corrosion resistance, improved product quality, and extended product life. However, sputtering-coated porous ceramics have extremely high requirements for the ceramic surface, resulting in low atomizer core yields and inconsistent product atomization effects. This has limited the application of porous ceramics in the atomization field, and therefore urgently needs improvement. Summary of the Invention

[0005] The first object of the present invention is to provide a method for preparing a porous ceramic material, which can improve the bonding strength between the porous ceramic material and the heating circuit, reduce the risk of the heating circuit falling off, and increase the life of the atomizer core.

[0006] A second object of the present invention is to provide a porous ceramic atomizing core.

[0007] The present invention provides a method for preparing a porous ceramic material, comprising the following steps:

[0008] S1. Weigh a certain amount of quartz sand, and spray the quartz sand into a high-temperature zone generated by an arc plasma torque using a spraying process to melt the surface of the quartz sand and vaporize impurities, and then quench to form spherical or / and quasi-spherical quartz powder;

[0009] S2. Weigh the quartz powder prepared in step S1, a plasticizer, a binder, a pore-forming agent, and a sintering aid according to the required mass fractions, mix them, and form them into a ceramic green body;

[0010] S3, heating to remove binder, remove plasticizer, binder and pore-forming agent in the ceramic green body, obtain ceramic precursor, and then sinter to obtain porous ceramic material.

[0011] The quenching atmosphere in step S1 preferably includes cooling water and argon atmosphere.

[0012] The quartz sand preferably passes through the high temperature zone in a spiral motion, and the parameter configuration of the arc plasma torque satisfies: the high temperature zone can melt the surface of the quartz sand passing therethrough, and the high temperature zone can vaporize impurities in the quartz sand passing therethrough.

[0013] The mass fractions in step S2 preferably include 20-80 parts of quartz powder, 20-80 parts of plasticizer, 20-80 parts of binder, 10-60 parts of pore former, and 1-30 parts of sintering aid. The particle size D50 of the quartz powder is preferably 5-100 μm.

[0014] The temperature rise schedule for debinding in step S3 preferably includes: rising from room temperature to 50°C at 0.02°C / min; rising from 50°C to 160°C at 0.01°C / min; rising from 160°C to 240°C at 0.005°C / min; rising from 240°C to 360°C at 0.01°C / min; rising from 360°C to 500°C at 0.05°C / min; and rising from 500°C to 600°C at 0.1°C / min.

[0015] The sintering temperature rise schedule in step S3 preferably includes: rising from room temperature to 900°C at 2-50°C / min; keeping at 900°C for 1 hour; rising from 900°C to 1100°C at 2-20°C / min; keeping at 1100°C for 2 hours; rising from 1100°C to 1300°C at 1-10°C / min; keeping at 1300°C for 2 hours.

[0016] The present invention also provides a porous ceramic material for atomization, which is prepared by any one of the above-mentioned methods for preparing the porous ceramic material.

[0017] The present invention provides a porous ceramic atomizing core, which is made by forming a heating circuit through a sputtering coating process using the porous ceramic material obtained by the above-mentioned porous ceramic material preparation method. The parameters of the sputtering coating process in some embodiments are as follows: background vacuum 1.0x10 -3 And below, deposition pressure 0.1 ~ 2Pa, deposition temperature 0 ~ 300 ℃.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] The porous ceramic material produced by this method has a high proportion of through-holes, strong liquid-conducting ability, and the ceramic matrix has good mechanical properties. The porous ceramic material produced by this method has a rounded surface under the microstructure, and the sintered neck is free of sharp corners and burrs. The service life of the porous ceramic atomizer core produced by this method is increased by more than 100%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a 300X electron microscope photograph of the porous ceramic material obtained in Example 1;

[0021] Figure 2 This is a 3000X electron microscope photograph of the porous ceramic material obtained in Example 1. DETAILED DESCRIPTION

[0022] The method for preparing the porous ceramic material of the present invention comprises the following steps:

[0023] S1. Weigh a certain amount of quartz sand, and spray the quartz sand into a high-temperature zone generated by an arc plasma torque using a spraying process to melt the surface of the quartz sand and vaporize impurities, and then quench to form spherical or / and quasi-spherical quartz powder;

[0024] The temperature of the high-temperature zone of the arc plasma torch is a critical parameter. It must ensure that the surface of the sprayed quartz sand melts as it passes through this zone. This temperature can be adjusted by adjusting the output power of the arc plasma torch. Generally, when the temperature within the arc reaches 3000°C, the surface of the quartz sand passing through it melts instantly. Specific parameter settings are subject to the requirements above and are not limited to the specific values ​​listed above.

[0025] The high-temperature zone of the arc plasma torch is also set to vaporize impurities in the sprayed quartz sand as it passes through this zone. This simultaneously purifies the sand while melting it. Generally, impurities in the sand are vaporized when the arc temperature reaches 3000°C.

[0026] Preferably, the quartz sand moves in a spiral motion through the high-temperature zone. The inner wall of the jet channel is a spiral structure, and after passing through the channel, the quartz sand is ejected in a spiral motion. When the surface of the particles melts to form a liquid layer, it is rapidly cooled by the dual action of the high-speed spiral inert gas and the outer liquid cooling device. Under the action of surface tension, the quartz powder particles are formed into spherical or quasi-spherical shapes.

[0027] The quenching step prevents particle growth, making particle size easier to control. Preferably, the quenching atmosphere includes cooling water and argon. Cooling water flows through pipes around the walls of the quenching chamber, maintaining the desired temperature. Low-temperature argon gas is introduced into the quenching chamber to create an argon quenching atmosphere. The quenching atmosphere can be room temperature.

[0028] This method sprays quartz sand into the high-temperature zone generated by an arc plasma torch. The high temperature within the arc instantly melts the sand surface, causing tension on the liquid surface to contract, forming spherical droplets. These droplets then vaporize and quench to form spherical and / or quasi-spherical quartz powder. The resulting quartz powder has a particle size (D50) primarily ranging from 5 to 100 μm. This eliminates any surface angularity and sharp edges on the sand particles, while also purifying them by vaporizing most low-temperature impurities in the high-temperature ion torch. Furthermore, the high heating temperature and rapid reaction rate prevent the particles from growing further after quenching in cooling water and an argon atmosphere, making particle size control easier.

[0029] S2. Weigh the quartz powder prepared in step S1, as well as a plasticizer, a binder, a pore-forming agent, and a sintering aid according to the required mass fractions, mix them, and form them into a ceramic green body;

[0030] The raw materials preferably include 20-80 parts by weight of quartz powder, 20-80 parts by weight of plasticizer, 20-80 parts by weight of binder, 10-60 parts by weight of pore former, and 1-30 parts by weight of sintering aid. The particle size D50 of the quartz powder is preferably 5-100 μm.

[0031] Among them, the plasticizers that can be used include but are not limited to PE (polyethylene), PVC (polyvinyl chloride), PVA (polyvinyl alcohol), etc., and the binders that can be used include but are not limited to paraffin. The plasticizers and binders can keep the blank from deformation, reduce the ceramic defects caused by thermal stress, and are beneficial to improving the yield rate of the porous ceramic atomization core.

[0032] Pore-forming agents that can be used include, but are not limited to, graphite powder and PMMA (polymethyl methacrylate). The pore-forming agents control the pore size and porosity of the porous ceramic atomization core to obtain a pore structure that penetrates each other in the porous ceramic atomization core.

[0033] The sintering aids that can be used include, but are not limited to, glass powder and clay. The sintering aids can lower the sintering temperature and promote the densification of the ceramic body.

[0034] The process of using the mixed material to form a ceramic green body may be an injection molding process, a dry pressing process, etc., which is not limited in the present invention.

[0035] S3, heating to remove binder, remove plasticizer, binder and pore-forming agent in the ceramic green body, obtain ceramic precursor, and then sinter to obtain porous ceramic material.

[0036] In some embodiments, the temperature rise schedule for debinding includes:

[0037] Stage 1: heating from room temperature to 50°C at 0.02°C / min;

[0038] The second stage: from 50°C to 160°C at 0.01°C / min;

[0039] The third stage: from 160°C to 240°C at 0.005°C / min;

[0040] Stage 4: from 240°C to 360°C at 0.01°C / min;

[0041] Stage 5: from 360°C to 500°C at 0.05°C / min;

[0042] Stage 6: Increase the temperature from 500°C to 600°C at 0.1°C / min.

[0043] Slow heating can prevent additives such as plasticizers from damaging the green body during the decomposition process.

[0044] In some embodiments, the sintering temperature regime includes:

[0045] The first stage: from room temperature to 900℃ at 2-50℃ / min;

[0046] The second stage: 900℃ for 1h;

[0047] The third stage: from 900℃ to 1100℃ at 2-20℃ / min;

[0048] The fourth stage: 1100℃ for 2h;

[0049] Stage 5: from 1100°C to 1300°C at 1-10°C / min;

[0050] Stage 6: Keep warm at 1300℃ for 2h.

[0051] Under this sintering temperature system, the appearance of the ceramic after sintering is regular and without deformation, the ceramic particles do not grow abnormally, the sintering necks between the particles are obvious, the through holes account for a large proportion, and the ceramic matrix has good mechanical properties.

[0052] The porous ceramic material for atomization is obtained by the above-mentioned porous ceramic material preparation method. The porous ceramic material obtained by the above-mentioned porous ceramic material preparation method is subjected to a sputtering coating process to form a heating circuit, thereby obtaining a porous ceramic atomization core. The parameters of the sputtering coating process can be as follows: background vacuum degree 1.0x10 -3 And below, deposition pressure 0.1 ~ 2Pa, deposition temperature 0 ~ 300 ℃.

[0053] The following is further described with reference to the accompanying drawings and embodiments.

[0054] Table 1 shows the raw material formulas of four examples.

[0055] Table 1 Formula content

[0056] Quartz powder pore-forming agent burning aid adhesive plasticizers Example 1 600 grams 480 grams 120 grams 400 grams 400 grams Example 2 600 grams 400 grams 200 grams 400 grams 400 grams Example 3 500 grams 580 grams 120 grams 400 grams 400 grams Example 4 550 grams 480 grams 170 grams 400 grams 400 grams

[0057] The quartz powder of Examples 1 to 4 is the quartz powder treated in step S1 above, the pore-forming agent is graphite powder, the sintering aid is glass powder, the binder is paraffin wax, and the plasticizer is PE (polyethylene).

[0058] The raw materials of Examples 1-4 were respectively injection molded to obtain ceramic green bodies, which were then heated to remove binder to obtain ceramic precursors, and then sintered to obtain porous ceramic materials.

[0059] Among them, the debinding temperature system is as follows: first stage: from room temperature to 50℃ at 0.02℃ / min; second stage: from 50℃ to 160℃ at 0.01℃ / min; third stage: from 160℃ to 240℃ at 0.005℃ / min; fourth stage: from 240℃ to 360℃ at 0.01℃ / min; fifth stage: from 360℃ to 500℃ at 0.05℃ / min; sixth stage: from 500℃ to 600℃ at 0.1℃ / min.

[0060] The sintering temperature rising system is as follows: the first stage: rising from room temperature to 900℃ at 5℃ / min; the second stage: keeping at 900℃ for 1h; the third stage: rising from 900℃ to 1100℃ at 5℃ / min; the fourth stage: keeping at 1100℃ for 2h; the fifth stage: rising from 1100℃ to 1300℃ at 5℃ / min; the sixth stage: keeping at 1300℃ for 2h.

[0061] Figure 1 A 300X electron microscope photograph of the porous ceramic material obtained in Example 1 is shown. Figure 2 3000X electron microscope photo of the porous ceramic material obtained in Example 1 is shown. Figure 1 It can be seen that the ceramic particles have no abnormal growth, and the sintering necks between the particles are obvious, and the through holes account for a large proportion. Figure 2It can be seen that the surface of the porous ceramic material is rounded under the microstructure, and there are no sharp corners or burrs on the sintered neck.

[0062] The porosity, pore size and strength of the porous ceramic materials prepared in Examples 1 to 4 are shown in Table 2. The porosity is measured by the Archimedes drainage method, and the pore size is measured by the bubble method.

[0063] Table 2 Porosity of porous ceramic materials

[0064] Porosity Aperture strength Example 1 58％ 20 microns <![CDATA[500N / mm 2 ]]> Example 2 52％ 15 microns <![CDATA[680N / mm 2 ]]> Example 3 65％ 27 microns <![CDATA[300N / mm 2 ]]> Example 4 56％ 18 microns <![CDATA[550N / mm 2 ]]>

[0065] By comparing Table 1 and Table 2, it can be found that the content of pore-forming agent affects the porosity and pore size, and the content of sintering aid affects the strength.

[0066] After further experiments, it was found that the mass requirements of the raw materials are: 20-80 parts of quartz powder, 20-80 parts of plasticizer, 20-80 parts of binder, 10-60 parts of pore-forming agent, and 1-30 parts of sintering aid. When the particle size D50 of the quartz powder is 5-100μm, the porosity of the porous ceramics produced is 50% to 80%, and the pore size is 5 to 50μm.

[0067] The porous ceramic materials prepared in Examples 1 to 4 were sputter-coated to obtain a porous ceramic atomizing core. The process parameters for sputter coating were as follows: background vacuum degree 1.0x10 -3 The membrane resistance and lifespan of the porous ceramic atomizer core were measured using a scratch test, with a deposition pressure of 0.5 Pa and a deposition temperature of 100°C. The membrane resistance and lifespan were tested using a 3-on, 8-off cycle to simulate human puffing. The test results are shown in Table 3.

[0068] Table 3 Membrane resistance and life of the porous ceramic atomizer core

[0069]

[0070]

[0071] Comparative Example: A comparative experiment was conducted using quartz powder that had not been treated in step S1 above.

[0072] The raw material formula for the comparative example is: 600 grams of quartz powder, 480 grams of graphite powder, 120 grams of glass powder, 400 grams of paraffin wax, and 400 grams of PE (polyethylene), which have not been treated by the method of the present invention. According to this formula, injection molding is performed to produce a ceramic green body, which is then heated to remove binder to obtain a ceramic precursor. This is then sintered to obtain a porous ceramic material. The prepared porous ceramic material is further sputter-coated to obtain a porous ceramic atomizer core. The debinding temperature system, sintering temperature system, and sputtering coating process parameters are the same as those in Example 1.

[0073] The same measuring method as in Example 1 was used to measure the properties of the product obtained in the comparative example as follows: the porosity of the porous ceramic material obtained in the comparative example was 55%, the pore size was 19 microns, and the strength was 400 N / mm 2 The porous ceramic atomizer core has a large fluctuation range of membrane resistance, which is more than ±0.5Ω. The service life fluctuates greatly, with the lowest failure rate being 100 puffs and the optimal service life reaching 1000 puffs.

[0074] Comparing the test results of Examples 1-4 and the comparative example, it was found that the porosity, pore size and strength of the porous ceramics prepared in Examples 1-4 and the comparative example were roughly the same. The fluctuation range of the membrane layer resistance of the porous ceramic atomizer core prepared in Examples 1-4 was ±0.1Ω, which was much smaller than the ±0.5Ω of the comparative example. The service life was increased by more than 100% compared with the comparative example, and the service life fluctuation range was smaller.

[0075] In addition, experiments have also found that the porous ceramic atomization core produced under the same process, using quartz powder treated by the process of the present invention, has a film resistance value reduced by 20% to 60% and a bonding strength increased by 30% to 50% compared with quartz powder not treated by the method of the present invention.

[0076] The impact of the binder removal heating schedule was tested: The binder removal heating schedule in Example 1 was replaced with the following: Stage 1: Room temperature to 50°C at 0.1°C / min; Stage 2: 50°C to 160°C at 0.1°C / min; Stage 3: 160°C to 240°C at 0.1°C / min; Stage 4: 240°C to 360°C at 0.2°C / min; Stage 5: 360°C to 500°C at 0.2°C / min; Stage 6: 500°C to 600°C at 0.2°C / min. The porosity, pore size, and strength of the resulting porous ceramic material were tested, and the yield rate dropped to 30%. The yield rate was 100% when the binder removal heating schedule in Example 1 was used.

[0077] Effect of sintering temperature schedule: The sintering temperature schedule in Example 1 was replaced with the following: first stage: heating from room temperature to 900°C at 50°C / min; second stage: holding at 900°C for 1 hour; third stage: heating from 900°C to 1100°C at 20°C / min; fourth stage: holding at 1100°C for 2 hours; fifth stage: heating from 1100°C to 1300°C at 1°C / min; sixth stage: holding at 1300°C for 2 hours. The resulting porous ceramic material had a porosity of 60%, a pore size of 22 microns, and a strength of 480 N / mm. 2Comparing this test result with the test results of Example 1 in Table 2, it was found that using the formulation of Example 1, after adopting a low-temperature fast firing and high-temperature slow firing process in the sintering step, the porous ceramic material obtained had a larger pore size and porosity, and a lower strength. Overall, both can meet the requirements of the porous ceramic atomizer core for porosity, pore size, and strength.

[0078] The present invention has been described in detail above through specific embodiments. Such detailed description is intended only to help those skilled in the art understand the present invention and is not to be construed as limiting the scope of protection of the present invention. Any modifications, equivalent transformations, and the like made by those skilled in the art to the above-described solutions based on the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing a porous ceramic material, wherein the porous ceramic material is used to form a heating circuit through a sputtering coating process to prepare a porous ceramic atomizing core, characterized in that: The preparation method comprises the following steps: S1. Weigh a certain amount of quartz sand and spray it into a high-temperature zone generated by an arc plasma torque using a spraying process to melt the surface of the quartz sand and vaporize impurities, and then form spherical or / and quasi-spherical quartz powder through a quenching atmosphere; S2. Weigh the quartz powder, plasticizer, binder, pore-forming agent, and sintering aid prepared in step S1 according to the required mass proportions, mix them, and form a ceramic green body. The required mass proportions include 20-80 parts of quartz powder, 20-80 parts of plasticizer, 20-80 parts of binder, 10-60 parts of pore-forming agent, and 1-30 parts of sintering aid. S3, heating and removing binder, removing plasticizer, binder and pore-forming agent in the ceramic embryo, obtaining a ceramic precursor, and then sintering to obtain a porous ceramic material, wherein the heating rate for removing binder is: from room temperature to 50°C at 0.02°C / min; from 50°C to 160°C at 0.01°C / min; from 160°C to 240°C at 0.005°C / min; from 240°C to 360°C at 0.01°C / min; and from 160°C to 240°C at 0.005°C / min. The temperature was increased from 360°C to 500°C at 0.05°C / min; from 500°C to 600°C at 0.1°C / min. The sintering heating rate was as follows: from room temperature to 900°C at 2-50°C / min; kept at 900°C for 1h; from 900°C to 1100°C at 2-20°C / min; kept at 1100°C for 2h; from 1100°C to 1300°C at 1-10°C / min; kept at 1300°C for 2h.

2. The method for preparing a porous ceramic material according to claim 1, wherein: The quenching atmosphere in step S1 includes cooling water and argon atmosphere.

3. The method for preparing a porous ceramic material according to claim 1, wherein: The quartz sand passes through the high temperature zone in a spiral motion, and the parameter configuration of the arc plasma torque satisfies: the high temperature zone can melt the surface of the quartz sand passing therethrough, and the high temperature zone can vaporize impurities in the quartz sand passing therethrough.

4. The method for preparing a porous ceramic material according to claim 1, wherein: The particle size D50 of the quartz powder is 5-100 μm.

5. A porous ceramic material for atomization, characterized in that: The porous ceramic material is prepared by the method according to any one of claims 1 to 4.

6. A porous ceramic atomizing core, characterized in that: The porous ceramic atomization core is made by forming a heating circuit through a sputtering coating process on the porous ceramic material as claimed in claim 5.

7. The porous ceramic atomizing core according to claim 6, characterized in that: The parameters of the sputtering coating process are as follows: background vacuum degree 1.0x10 -3 And below, deposition pressure 0.1~2Pa, deposition temperature 0~300℃.

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