Conductive ceramic heating body and preparation method therefor, and electronic cigarette

Abstract

A conductive ceramic heating body (100) and a preparation method therefor, and an electronic cigarette. The conductive ceramic heating body (100) is provided with a first end (101) and a second end (102) arranged opposite to each other. The conductivity of the conductive ceramic heating body (100) gradually increases in the direction from the first end (101) to the second end (102). The first end (101) of the conductive ceramic heating body (100) has relatively low conductivity and relatively large resistance, and generates relatively large heat after being electrified, and thus the first end (101) has relatively high temperature. The second end (102) has relatively large conductivity and relatively low resistance.

Description

Conductive ceramic heating element, preparation method thereof, and electronic cigarette

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 7, 2023, with application number 202311154490.6 and application name “Conductive ceramic heating element, preparation method thereof and electronic cigarette”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of electronic cigarettes, and in particular to a conductive ceramic heating element, a preparation method thereof, and an electronic cigarette. Background Art

[0003] Heat-not-burn (HBN) electronic cigarettes use a heating element to heat tobacco leaves until they emit smoke. In related technologies, the heating element can be conductive ceramic. However, when heated, conductive ceramics are prone to thermal expansion, affecting their structural stability. Furthermore, thermal stress mismatches between the heated conductive ceramic and other structural components can affect their connection, further compromising the use of the electronic cigarette.

[0004] Summary of the Invention

[0005] In view of this, the present application provides a conductive ceramic heating element, a preparation method thereof, and an electronic cigarette. The electrical conductivity of the conductive ceramic heating element gradually changes, and a gradient heating zone can be formed during use, which not only ensures the heat utilization rate, but also alleviates the effects of thermal expansion and thermal stress mismatch, thereby improving the performance of the conductive ceramic heating element.

[0006] In a first aspect, the present application provides a conductive ceramic heating element having a first end and a second end arranged opposite to each other, and the electrical conductivity of the conductive ceramic heating element gradually increases along the direction from the first end to the second end.

[0007] In one embodiment, the electrical conductivity of the conductive ceramic heating element gradually increases from 10 S / cm-90 S / cm to 0.5×10 4 S / cm-9×10 4 S / cm.

[0008] In one embodiment, the material of the conductive ceramic heating element includes insulating ceramic material, conductive ceramic material, and conductive non-ceramic material, and the conductive non-ceramic material includes acid-resistant material.

[0009] In one embodiment, the mass content of the insulating ceramic material in the conductive ceramic heating element is 65%-95%.

[0010] In one embodiment, the conductive ceramic material content in the conductive ceramic heating element is 4.5%-34.5% by mass.

[0011] In one embodiment, the conductive non-ceramic material in the conductive ceramic heating element has a mass content of 0.5%-5%.

[0012] In one embodiment, the mass content of the conductive non-ceramic material gradually increases from the first end to the second end.

[0013] In one embodiment, the mass content of the acid-resistant material gradually increases from the first end to the second end.

[0014] In one embodiment, the conductive non-ceramic material further includes an acid-resistant material, and the mass ratio of the non-acid-resistant material to the acid-resistant material in the conductive ceramic heating element is 1:(0.05-9).

[0015] In another embodiment, along the direction from the first end to the second end, the mass content of the acid-resistant material in the conductive non-ceramic material gradually increases from 0%-10% to 10%-100%, and the mass content of the acid-resistant material gradually decreases from 90%-100% to 0%-90%.

[0016] In one embodiment, the material of the conductive ceramic heating element further includes a sintering aid, and the mass content of the sintering aid in the conductive ceramic heating element is 0.5%-3%.

[0017] In a second aspect, the present application provides a method for preparing a conductive ceramic heating element, comprising:

[0018] An insulating ceramic material, a conductive ceramic material, a conductive non-ceramic material and a solvent are mixed and molded to obtain a green body, wherein the conductive non-ceramic material includes an acid-resistant material;

[0019] sintering the green body to obtain a preform;

[0020] The preform is etched with acid to obtain a conductive ceramic heating element. The conductive ceramic heating element has a first end and a second end that are relatively set. The electrical conductivity of the conductive ceramic heating element gradually increases along the direction from the first end to the second end.

[0021] In one embodiment, the insulating ceramic material, the conductive ceramic material, the conductive non-ceramic material and the solvent are mixed and molded to obtain a embryo, which includes: mixing the insulating ceramic material, the conductive ceramic material, the conductive non-ceramic material and the solvent, and preparing the embryo by dry pressing or tape casting.

[0022] In one embodiment, the sintering temperature is 1550° C.-1750° C., the sintering time is 0.5 h-2 h, and the sintering environment is a vacuum environment or an inert atmosphere filled with reducing gas.

[0023] In one embodiment, the concentration of the acid solution is 0.01 mol / L-0.1 mol / L.

[0024] In one embodiment, etching the preform with acid solution includes: placing the preform in the acid solution for etching, and moving the preform during etching until the preform leaves the acid solution, wherein the moving speed is 0.05 mm / min-1 mm / min.

[0025] In a third aspect, the present application provides an electronic cigarette, comprising the conductive ceramic heating element described in the first aspect or the conductive ceramic heating element prepared by the preparation method described in the second aspect.

[0026] The conductivity of the conductive ceramic heating element provided by the present application changes gradually. When the conductive ceramic heating element is powered on to generate heat, less heat is generated in the area with higher conductivity, and more heat is generated in the area with lower conductivity. This allows the conductive ceramic heating element to form a temperature gradient between the first end and the second end, and can fully utilize the heat generated by the conductive ceramic heating element. At the same time, the gradual temperature change can alleviate the situation of thermal expansion and reduce the thermal stress difference between the conductive ceramic heating element and other structures, which is beneficial to the connection between the conductive ceramic heating element and other structures and improves the performance of the conductive ceramic heating element. The preparation method of the conductive ceramic heating element is simple and easy to operate, which is beneficial to practical application. The electronic cigarette with the conductive ceramic heating element has high heat utilization rate and strong structural reliability, which is beneficial to practical application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. The specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] FIG1 is a schematic structural diagram of a conductive ceramic heating element provided in one embodiment of the present application;

[0029] FIG2 is a flow chart of a method for preparing a conductive ceramic heating element according to one embodiment of the present application;

[0030] FIG3 is a structural block diagram of an electronic cigarette provided in one embodiment of the present application.

[0031] Reference numerals: electronic cigarette-10; conductive ceramic heating element-100; first end-101; second end-102. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of this application in conjunction with the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of this application, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0033] FIG1 is a schematic diagram of the structure of a conductive ceramic heating element provided in one embodiment of the present application. Referring to FIG1 , the conductive ceramic heating element 100 has a first end 101 and a second end 102 that are relatively arranged relative to each other. The electrical conductivity of the conductive ceramic heating element 100 gradually increases along the direction from the first end 101 to the second end 102. In other words, the first end 101 of the conductive ceramic heating element 100 has a relatively low electrical conductivity and a relatively high electrical resistance, and generates relatively more heat and a relatively higher temperature after power is applied. The second end 102 has a relatively high electrical conductivity and a relatively low electrical resistance, and generates relatively less heat and a relatively lower temperature after power is applied. As a result, the temperature of the conductive ceramic heating element 100 gradually decreases from the first end 101 to the second end 102 after power is applied. In the related art, when the conductive ceramic heating element 100 is used in an electronic cigarette 10, since the heated object such as tobacco leaves does not completely cover the conductive ceramic heating element 100, the heat generated by the uncovered conductive ceramic heating element 100 is lost, and the heat utilization rate is low; at the same time, the conductive ceramic heating element 100 will undergo thermal expansion after heating, affecting its structural stability, and thermal stress mismatch will affect the connection between the conductive ceramic heating element 100 and other structures. The conductive ceramic heating element 100 provided in the present application has a gradual change in conductivity, which can form a gradual change in temperature after power is applied, thereby efficiently utilizing the heat generated by the conductive ceramic heating element 100, avoiding heat loss, and improving heat utilization rate; at the same time, the lower temperature area provides a buffer area for the thermal expansion of the conductive ceramic heating element 100 after heating, which can effectively suppress the adverse effects of the thermal expansion of the conductive ceramic heating element 100 and improve the structural stability of the conductive ceramic heating element 100. In addition, the thermal stress matching between the conductive ceramic heating element 100 and other structures in different temperature areas is improved, which can effectively suppress the effects caused by thermal stress mismatch and improve the performance and service life of the conductive ceramic heating element 100.

[0034] In the present application, when testing the electrical conductivity of the conductive ceramic heating element 100, an arbitrary position on the conductive ceramic heating element 100 is used as the origin, one electrode is connected to the origin, and the other electrode is connected to an arbitrary position in the direction from the first end 101 to the second end 102. The electrical conductivity at any position in the direction from the first end 101 to the second end 102 is tested, thereby obtaining the electrical conductivity distribution in the direction from the first end 101 to the second end 102. In the present application, the electrical conductivity of the conductive ceramic heating element 100 gradually increases along the direction from the first end 101 to the second end 102; "gradually increase" in the present application can be a linear increase or a nonlinear increase, etc., and the nonlinear increase can be a parabolic increase, a quasi-parabolic increase, a gradient increase, etc. In one embodiment of the present application, the gradual increase can be first remaining unchanged and then increasing nonlinearly. In another embodiment of the present application, the gradual increase can be a linear increase. In yet another embodiment of the present application, the gradual increase can be first remaining unchanged and then increasing gradiently. The present application does not limit the shape of the conductive ceramic heating element 100, and the shape of the conductive ceramic heating element 100 can be set according to the application needs. Specifically, the conductive ceramic heating element 100 can be a regular shape, such as a cuboid, a cube, a cylinder, a cone, etc., or an irregular shape. For example, the conductive ceramic heating element 100 shown in FIG1 has a pointed end. In one embodiment of the present application, the length of the conductive ceramic heating element 100 is 10cm-15cm, the width is 0.5cm-2cm, and the thickness is 0.05cm-1cm. The shape of the conductive ceramic heating element 100 is regular, which is conducive to the setting of the conductive ceramic heating element 100 in the electronic cigarette 10, and is also conducive to the conductive ceramic heating element 100 being covered by the heated object, thereby improving the heating efficiency. Specifically, the length of the conductive ceramic heating element 100 may be, but is not limited to, 10 cm, 11 cm, 12 cm, 13 cm, 14 cm, or 15 cm, the width may be, but is not limited to, 0.5 cm, 1 cm, 1.5 cm, or 2 cm, and the thickness may be, but is not limited to, 0.05 cm, 0.08 cm, 0.1 cm, 0.3 cm, 0.5 cm, 0.8 cm, or 1 cm. The first end 101 and the second end 102 of the conductive ceramic heating element 100 are arranged opposite to each other, also referred to as being arranged opposite to each other. For example, when the conductive ceramic heating element 100 is a rectangular parallelepiped, the two ends along its length direction may be the first end 101 and the second end 102, or the two ends along its width direction may be the first end 101 or the second end 102, or the two ends along its thickness direction may be the first end 101 or the second end 102. In one embodiment of the present application, the conductive ceramic heating element 100 has a first end 101 and a second end 102 arranged opposite to each other in its extension direction. The extending direction of the conductive ceramic heating element 100 is the extending direction of the largest side length among all surfaces of the conductive ceramic heating element 100 .In one embodiment of the present application, the direction from the first end 101 to the second end 102 can be the length direction of the conductive ceramic heating element 100; that is, along the length direction of the conductive ceramic heating element 100, the conductivity of the conductive ceramic heating element 100 gradually increases.

[0035] In one embodiment of the present application, the electrical conductivity of the conductive ceramic heating element 100 gradually increases from 10S / cm-90S / cm to 0.5×10 4 S / cm-9×10 4 S / cm. That is, the minimum conductivity of the conductive ceramic heating element 100 is 10S / cm-90S / cm, and the maximum conductivity is 0.5×10 4 S / cm-9×10 4 S / cm; The conductivity span of the conductive ceramic heating element 100 is appropriate, so that the temperature span of the conductive ceramic heating element 100 after heating is appropriate. Therefore, the area with higher temperature can fully heat the heated object, and the area with lower temperature can improve the structural stability of the conductive ceramic heating element 100, thereby improving the performance and service life of the conductive ceramic heating element 100. Specifically, the minimum conductivity of the conductive ceramic heating element 100 can be, but is not limited to, 10S / cm-30S / cm, 20S / cm-50S / cm, 30S / cm-60S / cm, 40S / cm-80S / cm, or 60S / cm-90S / cm, etc., and the maximum conductivity of the conductive ceramic heating element 100 can be, but is not limited to, 0.5×10 4 S / cm-2×10 4 S / cm, 1×10 4 S / cm-3×10 4 S / cm, 2×10 4 S / cm-5×10 4 S / cm, 4×10 4 S / cm-7×10 4 S / cm, or 6×10 4 S / cm-9×10 4 In one embodiment of the present application, the electrical conductivity of the conductive ceramic heating element 100 can be gradually increased from 60 S / cm to 90 S / cm along the direction from the first end 101 to the second end 102 to 6×10 4 S / cm-9×10 4 In one embodiment of the present application, the electrical conductivity of the conductive ceramic heating element 100 can be gradually increased from 40 S / cm to 90 S / cm along the direction from the first end 101 to the second end 102 to 6×10 4 S / cm-9×10 4 S / cm.

[0036] In one embodiment of the present application, the material of the conductive ceramic heating element 100 includes insulating ceramic material, conductive ceramic material, and conductive non-ceramic material, and the conductive non-ceramic material includes acid-resistant material. The insulating ceramic material ensures the heating performance of the conductive ceramic heating element 100, the conductive ceramic material ensures the conductive performance of the conductive ceramic heating element 100, and the conductive non-ceramic material ensures the conductive performance of the conductive ceramic heating element 100 and the gradual distribution of conductivity. In the present application, the insulating ceramic material is a non-conductive ceramic material with a resistivity greater than 10 7 Ω·cm; Conductive ceramic material is a ceramic material with conductive properties, and its resistivity is less than or equal to 10 7 Ω·cm; acid-resistant materials are materials that have conductive properties and can react with acid; the resistivity in this application refers to the resistivity value under 25°C. In one embodiment of this application, the resistivity of the conductive ceramic material can be less than or equal to 10 3 Ω·cm. In another embodiment of the present application, the resistivity of the conductive ceramic material may be less than or equal to 10 2 Ω·cm.

[0037] In one embodiment of the present application, the weight content of the insulating ceramic material in the conductive ceramic heating element 100 is 65%-95%, which helps to increase the temperature of the conductive ceramic heating element 100 after power is applied, helps heat the heated object, and improves the heating efficiency of the conductive ceramic heating element 100. In other words, the insulating ceramic material is the main component of the conductive ceramic heating element 100. Specifically, the weight content of the insulating ceramic material in the conductive ceramic heating element 100 can be, but is not limited to, 65%, 68%, 70%, 75%, 77%, 80%, 84%, 85%, 90%, or 95%. In one embodiment of the present application, the weight content of the insulating ceramic material in the conductive ceramic heating element 100 can be 65%-90%. In another embodiment of the present application, the weight content of the insulating ceramic material in the conductive ceramic heating element 100 can be 65%-80%. In one embodiment of the present application, the insulating ceramic material includes at least one of zirconium oxide and aluminum oxide. The above insulating ceramic material helps to improve the mechanical properties of the conductive ceramic heating element 100 and increase the service life of the conductive ceramic heating element 100.

[0038] In one embodiment of the present application, the mass content of the conductive ceramic material in the conductive ceramic heating element 100 is 4.5%-34.5%, which is beneficial to improving the conductive performance and conductivity of the conductive ceramic heating element 100. Specifically, the mass content of the conductive ceramic material in the conductive ceramic heating element 100 can be, but is not limited to, 4.5%, 5%, 10%, 12%, 15%, 16%, 20%, 25%, 28%, 30%, or 34%, etc. In one embodiment of the present application, the mass content of the conductive ceramic material in the conductive ceramic heating element 100 can be 10%-33%. In another embodiment of the present application, the mass content of the conductive ceramic material in the conductive ceramic heating element 100 can be 20%-30%. In one embodiment of the present application, the conductive ceramic material includes at least one of silicon carbide and molybdenum disilicide. The above-mentioned conductive ceramic material is beneficial to improving the conductivity of the conductive ceramic heating element 100 and enhancing the mechanical properties of the conductive ceramic heating element 100, which is beneficial to the practical application of the conductive ceramic heating element 100. It can be understood that the insulating ceramic material and the conductive ceramic material in the present application are acid-resistant and do not react with acid.

[0039] In one embodiment of the present application, the mass content of the conductive non-ceramic material in the conductive ceramic heating element 100 is 0.5%-5%, which is conducive to regulating the electrical conductivity of the conductive ceramic heating element 100. Specifically, the mass content of the conductive non-ceramic material in the conductive ceramic heating element 100 can be, but is not limited to, 0.5%, 1%, 2%, 2.5%, 3%, 3.7%, 4%, 4.2%, 4.5%, or 5%. In one embodiment of the present application, the mass content of the conductive non-ceramic material in the conductive ceramic heating element 100 can be 0.5%-3%. In one embodiment of the present application, the mass content of the conductive non-ceramic material in the conductive ceramic heating element 100 can be 3%-5%. In this application, the conductive non-ceramic material includes an acid-resistant material, that is, a conductive substance that can react with acid, and can specifically be a metal or a non-metallic substance. In one embodiment of the present application, the acid-resistant material includes at least one of aluminum, zinc, iron, tin, lead, nickel, chromium, titanium, cobalt, and manganese.

[0040] In one embodiment of the present application, the conductive non-ceramic material also includes an acid-resistant material. The acid-resistant material is a conductive substance that does not react with acid, and can be specifically a metal substance or a non-metal substance. The acid-resistant material can improve the strength of the conductive ceramic heating element 100, which is beneficial to its practical application. In one embodiment of the present application, the acid-resistant material includes at least one of copper, silver, platinum, gold, tungsten, and molybdenum. In one embodiment of the present application, the mass ratio of the non-acid-resistant material and the acid-resistant material in the conductive ceramic heating element 100 is 1: (0.05-9), which can not only regulate the conductivity of the conductive ceramic heating element 100, but also ensure the strength of the conductive ceramic heating element 100 and improve the performance of the conductive ceramic heating element 100. Specifically, the mass ratio of acid-resistant material to acid-resistant material in the conductive ceramic heating element 100 can be, but is not limited to, 1:0.05, 1:0.08, 1:0.1, 1:0.15, 1:0.2, 1:0.5, 1:1, 1:3, 1:5, 1:6, 1:8, or 1:9.

[0041] In one embodiment of the present application, the mass content of the conductive non-ceramic material in the conductive ceramic heating element 100 gradually increases in the direction from the first end 101 to the second end 102. The change in the mass content of the conductive non-ceramic material in the conductive ceramic heating element 100 can regulate the change in the electrical conductivity of the conductive ceramic heating element 100. The electrical conductivity of the area with a relatively low mass content of the conductive non-ceramic material is relatively low, and the electrical conductivity of the area with a relatively high mass content of the conductive non-ceramic material is relatively high. In one embodiment of the present application, the mass content of the acid-resistant material in the conductive ceramic heating element 100 gradually increases in the direction from the first end 101 to the second end 102. The change in the mass content of the acid-resistant material is beneficial to the regulation of the electrical conductivity of the conductive ceramic heating element 100 and is beneficial to the use of the electrical conductivity of the conductive ceramic heating element 100.

[0042] In one embodiment of the present application, when the conductive non-ceramic material includes an acid-resistant material, the mass of the acid-resistant material in the conductive ceramic heating element 100 does not significantly change along the direction from the first end 101 to the second end 102. In other words, the mass difference of the acid-resistant material in the conductive ceramic heating element 100 along the direction from the first end 101 to the second end 102 does not exceed 0.1%, which helps to ensure the mechanical properties of the conductive ceramic heating element 100. In other words, the mass difference of the acid-resistant material in the first region of the conductive ceramic heating element 100 and the mass difference of the acid-resistant material in the second region of the conductive ceramic heating element 100 along the direction from the first end 101 to the second end 102 does not exceed 0.1%.

[0043] In one embodiment of the present application, when the conductive non-ceramic material includes an acid-resistant material, along the direction from the first end 101 to the second end 102, the mass content of the non-acid-resistant material in the conductive non-ceramic material gradually increases from 0%-10% to 10%-100%, and the mass content of the acid-resistant material gradually decreases from 90%-100% to 0%-90%; the change in the mass content of the non-acid-resistant material can regulate the conductivity of the conductive ceramic heating element 100, and the acid-resistant material ensures the mechanical properties of the conductive ceramic heating element 100. Specifically, along the direction from the first end 101 to the second end 102, the mass content of the acid-resistant material in the conductive non-ceramic material can gradually increase from 0%-3%, 3%-5%, 1%-5%, or 5%-9% to 20%-45%, 35%-50%, 40%-70%, or 60%-100%, etc.; along the direction from the first end to the second end, the mass content of the acid-resistant material in the conductive non-ceramic material can gradually decrease from 97%-100%, 95%-97%, 95%-99%, or 91%-95% to 55%-80%, 50%-65%, 30%-60%, or 3%-40%, etc. In one embodiment of the present application, when the conductive non-ceramic material includes an acid-resistant material, the weight content of the non-acid-resistant material in the conductive non-ceramic material gradually increases from 0%-10% to 20%-97% along the direction from the first end 101 to the second end 102, and the weight content of the acid-resistant material gradually decreases from 90%-100% to 3%-80%. In one embodiment of the present application, when the conductive non-ceramic material includes an acid-resistant material, the weight content of the non-acid-resistant material in the conductive non-ceramic material gradually increases from 0%-10% to 50%-95% along the direction from the first end 101 to the second end 102, and the weight content of the acid-resistant material gradually decreases from 90%-100% to 5%-50%.

[0044] In one embodiment of the present application, the material of the conductive ceramic heating element 100 also includes a sintering aid. The sintering aid in the conductive ceramic heating element 100 is beneficial to improving the performance of the conductive ceramic heating element 100 and is beneficial to the practical application of the conductive ceramic heating element 100. In one embodiment of the present application, the mass content of the sintering aid in the conductive ceramic heating element 100 is 0.5%-3%. Specifically, the mass content of the sintering aid in the conductive ceramic heating element 100 may be, but is not limited to, 0.5%, 1%, 1.5%, 2%, 2.5%, or 3%, etc. In one embodiment, the mass content of the sintering aid in the conductive ceramic heating element 100 is 0.5%-2%. In another embodiment, the mass content of the sintering aid in the conductive ceramic heating element 100 is 0.8%-1.5%. In one embodiment of the present application, the sintering aid includes at least one of silicon nitride and silicon oxide.

[0045] In one embodiment of the present application, the conductive ceramic heating element 100 includes an insulating ceramic material having a mass content of 65%-95%, a conductive ceramic material having a mass content of 4.5%-34.5%, and a conductive non-ceramic material having a mass content of 0.5%-5%. In another embodiment of the present application, the conductive ceramic heating element 100 includes an insulating ceramic material having a mass content of 65%-94.5%, a conductive ceramic material having a mass content of 4.5%-34.5%, a conductive non-ceramic material having a mass content of 0.5%-5%, and a sintering aid having a mass content of 0.5%-3%.

[0046] The present application provides a method for preparing a conductive ceramic heating element 100, which can produce the conductive ceramic heating element 100 in any of the above embodiments. Please refer to Figure 2, which is a flow chart of the method for preparing a conductive ceramic heating element provided in one embodiment of the present application, including the following steps.

[0047] S201: mixing insulating ceramic material, conductive ceramic material, conductive non-ceramic material and solvent to form a green body, wherein the conductive non-ceramic material includes acid-resistant material.

[0048] S202: Sintering the green body to obtain a preform.

[0049] S203: Etching the preform with acid solution to obtain a conductive ceramic heating element 100. The conductive ceramic heating element 100 has a first end 101 and a second end 102 that are relatively arranged. The electrical conductivity of the conductive ceramic heating element 100 gradually increases along the direction from the first end 101 to the second end 102.

[0050] In the present application, the raw materials for preparing the conductive ceramic heating element 100 are mixed, formed, sintered, and then etched to obtain a conductive ceramic heating element 100 with a gradual change in conductivity; this preparation method is simple, easy to operate, does not require large equipment, and is conducive to the production and application of conductive ceramic heating elements.

[0051] In S201, a green body can be prepared by dry pressing or tape casting. In one embodiment of the present application, an insulating ceramic material, a conductive ceramic material, and a conductive non-ceramic material are mixed with a solvent and then granulated, and then dry pressed to obtain a green body. The solvent can be a binder. In one embodiment of the present application, the dry pressing pressure can be 40MPa-100MPa, which helps to improve the density of the green body and the conductive ceramic heating element 100, and enhance the performance of the conductive ceramic heating element 100. Specifically, the dry pressing pressure can be, but is not limited to, 40MPa, 50MPa, 75MPa, 80MPa, 90MPa, or 100MPa. In another embodiment of the present application, the insulating ceramic material, the conductive ceramic material, and the conductive non-ceramic material are mixed with a solvent to form a slurry, which is then tape-cast to obtain a green body. The solvent can be a substance capable of dispersing the raw materials. The specific material of the solvent in this application can be selected based on the molding process and is not limited to this. In this application, the molding process can be carried out in a mold to obtain the conductive ceramic heating element 100 of the desired shape. In one embodiment of the present application, the mass content of the solvent in the mixed substance can be 1%-3% (e.g., 1%, 1.5%, 2%, 2.5% or 3%). In a specific embodiment, the mass content of the solvent in the mixed substance is 1%-3%, and the solvent is polyvinyl butyral. After mixing, the green body is obtained by dry pressing.

[0052] In one embodiment of the present application, an insulating ceramic material, a conductive ceramic material, a conductive non-ceramic material and a solvent can be mixed and then formed into a green body, and the conductive non-ceramic material includes an acid-resistant material and an acid-resistant material. The acid-resistant material and the acid-resistant material can jointly regulate the electrical conductivity of the conductive ceramic heating element 100, and the acid-resistant material can regulate the gradual distribution of the electrical conductivity of the conductive ceramic heating element 100. The acid-resistant material will not react with the acid solution and can be retained in the green body, thereby improving the strength of the conductive ceramic heating element 100. In one embodiment of the present application, an insulating ceramic material, a conductive ceramic material, a conductive non-ceramic material, a sintering aid and a solvent can be mixed and then formed into a green body. The addition of the sintering aid can improve the performance of the conductive ceramic heating element 100, which helps to improve the performance of the conductive ceramic heating element 100.

[0053] In S202, the green body can be sintered to remove volatile and easily decomposable substances, such as organic matter, so as to ensure the mechanical properties of the conductive ceramic heating element 100 obtained. In one embodiment of the present application, the sintering temperature can be 1550℃-1750℃, the sintering time can be 0.5h-2h, and the sintering is carried out in a vacuum environment or an inert atmosphere filled with a reducing gas (such as hydrogen, etc.). The above sintering process is conducive to the removal of organic matter and other substances in the green body, thereby ensuring the performance of the preform and the conductive ceramic heating element 100. Specifically, the sintering temperature can be but not limited to 1550℃, 1570℃, 1600℃, 1620℃, 1650℃, 1675℃, 1700℃, 1730℃, or 1750℃, etc., and the sintering time can be but not limited to 0.5h, 1h, 1.5h, or 2h, etc. In one embodiment, sintering can be carried out in a vacuum furnace.

[0054] In S203, by placing the preform in an acid solution, the acid-resistant material in the conductive non-ceramic material will react with the acid, and by controlling the reaction between the acid-resistant material in the preform and the acid, a conductive ceramic heating element 100 with a gradually varying conductivity distribution is obtained; the acid-resistant material that reacts with the acid is etched away, providing a buffer space for the thermal expansion that occurs when the conductive ceramic heating element 100 is in use, thereby improving the structural stability of the conductive ceramic heating element 100.

[0055] In one embodiment of the present application, the concentration of the acid solution is 0.01 mol / L-0.1 mol / L. The acid solution in the present application is a dilute acid, which can react with acid-sensitive materials while not affecting the performance of other components; at the same time, the acid concentration is relatively low, which can avoid non-gradient etching caused by acid residue in the preform due to capillary phenomena when the concentration is high. Specifically, the concentration of the acid solution can be, but is not limited to, 0.01 mol / L, 0.03 mol / L, 0.05 mol / L, 0.07 mol / L, or 0.1 mol / L. In one embodiment of the present application, the concentration of the acid solution can be 0.01 mol / L-0.05 mol / L. In another embodiment of the present application, the concentration of the acid solution can be 0.05 mol / L-0.1 mol / L. The acid solution in the present application can be an inorganic acid or an organic acid, as long as it can react with acid-sensitive materials. Specifically, the acid solution can be, but is not limited to, at least one of hydrochloric acid, sulfuric acid, and nitric acid. In one embodiment of the present application, the etching temperature can be less than or equal to 25°C, which ensures the etching process while not damaging or etching other components in the preform, which is beneficial to improving the performance of the conductive ceramic heating element 100.

[0056] In one embodiment of the present application, an acid solution is used to etch a preform, comprising: placing the preform in an acid solution for etching, and during the etching process, moving the preform until the preform leaves the acid solution. By moving the preform during the etching process, a part of the preform can leave the acid solution first, thereby avoiding further reaction between the acid-resistant material in the part and the acid solution, and a part of the preform leaves the acid solution later, so that the acid-resistant material in the part that has not left the acid solution has a long reaction time with the acid solution, and more acid-resistant material is etched away, so that the mass content of the acid-resistant material in the preform after etching has a gradual distribution, thereby making the electrical conductivity of the conductive ceramic heating element 100 have a gradual distribution; that is, by controlling the time when different areas of the preform are etched, the gradual distribution of the electrical conductivity of the conductive ceramic heating element 100 is achieved. It can be understood that the preform has a third end and a fourth end that are relatively arranged. During etching, the preform is lifted in the direction from the third end to the fourth end so that the area near the fourth end leaves the acid liquid first, and the part near the third end leaves the acid liquid later. The third end after etching is the first end 101, and the fourth end after etching is the second end 102. In one embodiment of the present application, when the conductive non-ceramic material also includes an acid-resistant material, the acid-resistant material will not react with the acid during etching, thereby ensuring the toughness and strength of the conductive ceramic heating element 100, which is beneficial to improving the service life of the conductive ceramic heating element 100.

[0057] In the present application, the preform can be completely placed in the acid solution, and then the preform can be moved in the direction away from the acid solution until the preform has completely left the acid solution; the preform can also be placed in the acid solution, and the fourth end is flush with the surface of the acid solution, and then the preform can be moved in the direction away from the acid solution until the preform has completely left the acid solution; the preform near the third end can also be placed in the acid solution, and the preform near the fourth end is not placed in the acid solution, and then the preform can be moved in the direction away from the acid solution until the preform has completely left the acid solution. In the present application, different forms of conductivity gradient distribution can be achieved by controlling the moving speed of the preform during etching, for example, it can move uniformly, it can move non-uniformly, it can move a certain distance and then stay for a period of time before continuing to move, etc. The moving mode can be selected as needed. In one embodiment of the present application, the moving speed of the preform during etching is 0.05mm / min-1mm / min, so that the conductivity span of the conductive ceramic heating element 100 is appropriate, which is conducive to the practical application of the conductive ceramic heating element 100. Specifically, the moving speed may be, but is not limited to, 0.05 mm / min, 0.1 mm / min, 0.3 mm / min, 0.5 mm / min, 0.6 mm / min, 0.9 mm / min, or 1 mm / min.

[0058] This application provides an electronic cigarette 10, comprising a conductive ceramic heating element 100 according to any of the above embodiments, or a conductive ceramic heating element 100 produced by the preparation method according to any of the above embodiments. The conductive ceramic heating element 100 has excellent performance and a long service life, thereby enhancing the product competitiveness of the electronic cigarette 10.

[0059] In one embodiment of the present application, a metal layer is provided on one side of the surface of the conductive ceramic heating element 100. Specifically, the metal layer can be formed by screen printing a metal slurry, and the metal layer can cover a portion of the surface of the conductive ceramic heating element 100. The provided metal layer can be connected to an electrode of a power supply to enable the conductive ceramic heating element 100 to generate heat when powered, thereby achieving a heating function. It can be understood that the electronic cigarette 10 is a heat-not-burn electronic cigarette at this time; in the related art, the conductive ceramic heating element 100 is placed in a heated object such as tobacco leaves, and the heated object does not completely wrap the conductive ceramic heating element 100, which will cause heat loss. The present application sets a conductive ceramic heating element 100 with a gradient conductivity, so that the temperature at different positions of the conductive ceramic heating element 100 has a difference when it heats up, so that the first end 101 with low conductivity and high temperature when heated can be placed in the heated object, and the heated object can completely cover the area near the first end 101; the second end 102 with high conductivity and low temperature when heated can be wrapped by the heated object, or it can not be wrapped by the heated object. Since the area near the second end 102 generates less heat, no obvious heat will be caused. loss, thereby improving heat utilization rate; in the related art, after the conductive ceramic heating element 100 is connected to other structures (such as metal layers, etc.), the conductive ceramic heating element 100 will undergo thermal expansion, and will also produce thermal mismatch with other structures, affecting its performance; in the present application, a conductive ceramic heating element 100 with varying electrical conductivity is provided, so that the conductive ceramic heating element 100 has different temperatures at different positions after heating. In addition, the etched acid-resistant metal material improves the thermal expansion of the conductive ceramic heating element 100, improves the stability of the conductive ceramic heating element 100, and at the same time, the bonding performance between the conductive ceramic heating element 100 and other structures is improved, thereby improving its performance and service life, which is beneficial to the practical application of the electronic cigarette 10.

[0060] FIG3 is a block diagram of the structure of an electronic cigarette provided in one embodiment of the present application. As shown in FIG3 , in one embodiment of the present application, the electronic cigarette 10 includes an atomizing core, which includes a conductive ceramic heating element 100. Specifically, the conductive ceramic heating element 100 has a porous structure, which facilitates atomization. It can be understood that the electronic cigarette 10 is an atomizing electronic cigarette.

[0061] The effects of the technical solution of this application are further illustrated below through specific examples.

[0062] Example 1

[0063] 65 parts by weight of zirconium oxide powder, 30 parts by weight of silicon carbide powder, 2.5 parts by weight of silicon nitride powder, 2.7 parts by weight of nickel powder, and 0.3 parts by weight of copper powder were dry-mixed to form a mixed powder. Polyvinyl butyral (PVB) was added to the mixed powder and granulated to obtain granulated powder, with the mass of PVB accounting for 1% of the mass of the mixed powder. 5 g of the granulated powder was placed in a mold (12 cm long and 1.2 cm wide) and maintained at a pressure of 40 MPa for 3 minutes to obtain a green body.

[0064] The green body is placed vertically in a vacuum furnace along its length direction and sintered at 1600° C. for 30 minutes to obtain a preform. The preform has a third end and a fourth end that are oppositely arranged along its length direction.

[0065] The preform is completely immersed in a dilute sulfuric acid solution (concentration of 0.1 mol / L) and etched with ultrasonic vibration, and the preform is lifted along the length direction of the preform at a speed of 1 mm / min until the preform completely leaves the dilute sulfuric acid solution, wherein the fourth end leaves the dilute sulfuric acid solution first and the third end leaves the dilute sulfuric acid solution last; then, after water washing and vacuum drying, a conductive ceramic heating element 100 is obtained. The conductive ceramic heating element 100 has a first end 101 and a second end 102 arranged opposite to each other, the first end 101 is the third end after etching, and the second end 102 is the fourth end after etching.

[0066] Example 2

[0067] 70 parts by weight of zirconium oxide powder, 20 parts by weight of silicon carbide powder, 2.5 parts by weight of silicon nitride powder, 2.8 parts by weight of nickel powder, and 0.2 parts by weight of copper powder were dry-mixed to form a mixed powder. PVB was added to the mixed powder and granulated to obtain granulated powder, with the mass of PVB accounting for 1% of the mass of the mixed powder. 5 g of the granulated powder was placed in a mold (12 cm long and 1.2 cm wide) and maintained at a pressure of 40 MPa for 3 minutes to obtain a green body.

[0068] The green body is placed vertically in a vacuum furnace along its length direction and sintered at 1600° C. for 30 minutes to obtain a preform. The preform has a third end and a fourth end that are oppositely arranged along its length direction.

[0069] The preform is completely immersed in a dilute sulfuric acid solution (concentration of 0.1 mol / L) and etched with ultrasonic vibration, and the preform is lifted along the length direction of the preform at a speed of 1 mm / min until the preform completely leaves the dilute sulfuric acid solution, wherein the fourth end leaves the dilute sulfuric acid solution first and the third end leaves the dilute sulfuric acid solution last; then, after water washing and vacuum drying, a conductive ceramic heating element 100 is obtained. The conductive ceramic heating element 100 has a first end 101 and a second end 102 arranged opposite to each other, the first end 101 is the third end after etching, and the second end 102 is the fourth end after etching.

[0070] Example 3

[0071] 70 parts by weight of zirconium oxide powder, 25 parts by weight of silicon carbide powder, 4.75 parts by weight of zinc powder, and 0.25 parts by weight of copper powder were dry-mixed to form a mixed powder. PVB was added to the mixed powder and granulated to obtain granulated powder, with the mass of PVB accounting for 1% of the mass of the mixed powder. 5 g of the granulated powder was placed in a mold (12 cm long and 1.2 cm wide) and maintained at a pressure of 40 MPa for 3 minutes to obtain a green body.

[0072] The green body is placed vertically in a vacuum furnace along its length direction and sintered at 1600° C. for 30 minutes to obtain a preform. The preform has a third end and a fourth end that are oppositely arranged along its length direction.

[0073] The preform is completely immersed in a dilute sulfuric acid solution (concentration of 0.01 mol / L) and etched with ultrasonic vibration, and the preform is lifted along the length direction of the preform at a speed of 1 mm / min until the preform completely leaves the dilute sulfuric acid solution, wherein the fourth end leaves the dilute sulfuric acid solution first and the third end leaves the dilute sulfuric acid solution last; then, the conductive ceramic heating element 100 is obtained after water washing and vacuum drying. The conductive ceramic heating element 100 has a first end 101 and a second end 102 arranged opposite to each other, the first end 101 is the third end after etching, and the second end 102 is the fourth end after etching. The mass ratio of zinc and copper in the conductive ceramic heating element 100 is 1:0.1.

[0074] Example 4

[0075] The method is substantially the same as Example 3, except that the etching time is shorter, so that the mass ratio of zinc to copper in the conductive ceramic heating element 100 is 1:0.06.

[0076] Example 5

[0077] It is substantially the same as Example 3, except that the mixed powder includes 0.5 parts by weight of zinc powder and 4.5 parts by weight of copper powder, and the mass ratio of zinc to copper in the conductive ceramic heating element 100 is 1:12.

[0078] Comparative Example 1

[0079] It is substantially the same as Example 3, except that etching is not performed and the preform is directly used as the conductive ceramic heating element 100 .

[0080] Comparative Example 2

[0081] The method is substantially the same as Example 3, except that 4.75 parts by weight of zinc powder and 0.25 parts by weight of copper powder are replaced with 5 parts by weight of copper powder.

[0082] Performance testing

[0083] The conductive ceramic heating element 100 prepared in the above-mentioned embodiment and comparative example was subjected to conductivity measurement, wherein one electrode was fixed at the second end 102 (as the origin), and by changing the position of the other electrode on the conductive ceramic heating element 100, the voltage, current and distance between the two electrodes were measured, and the average conductivity at positions at different distances from the origin along the length direction of the conductive ceramic heating element 100 was calculated. The results are shown in Table 1.

[0084] Table 1 Conductivity test results

[0085] After silk-screening the metal electrodes on the surface of the conductive ceramic heating element 100 prepared in the embodiment and the comparative example, the external circuits were soldered and the conductive ceramic heating element 100 was heated by power. When the temperature rose to 250°C, the heating was stopped and the conductive ceramic heating element 100 was cooled to room temperature using a room temperature (25°C) fan and then heated to 250°C again. After 10,000 cycles, the tensile strength of the soldering pads (the soldering pad length was less than 3.5 mm, the width was less than 3 mm, and the height was less than 1.5 mm) on the conductive ceramic heating element 100 in the embodiment and the comparative example was tested according to the IPC-2221 standard. The results are shown in Table 2.

[0086] Table 2 Tensile strength test results

[0087] It can be seen from the above results that, compared with the comparative example, in the embodiment of the present application, the conductivity of the conductive ceramic undergoes a gradient change through acid etching, so that the temperature of the conductive ceramic heating element 100 after heating undergoes a gradient change, and the etched acid-resistant metal material improves the thermal expansion of the conductive ceramic heating element 100, and improves the stability of the conductive ceramic heating element 100. At the same time, the bonding performance (tensile strength) between the conductive ceramic heating element 100 with a temperature gradient change and the welding electrode is improved, thereby improving the performance and service life of the conductive ceramic heating element 100, which is beneficial to the practical application of the electronic cigarette 10; at the same time, compared with Examples 4-5, the conductive ceramic heating element 100 obtained in Examples 1-3 has an appropriate conductivity gradient change, and the measured tensile strength is higher, which significantly improves the performance of the conductive ceramic heating element 100.

[0088] The above is an exemplary embodiment of the present application and should not be construed as limiting the scope of the present application. It should be noted that those skilled in the art may make improvements and modifications without departing from the principles of the present application, and such improvements and modifications are also considered to be within the scope of protection of the present application.

Claims

1. A conductive ceramic heating element (100), characterized in that: The conductive ceramic heating element (100) has a first end (101) and a second end (102) that are arranged opposite to each other, and the electrical conductivity of the conductive ceramic heating element (100) gradually increases in a direction from the first end (101) to the second end (102).

2. The conductive ceramic heating element (100) according to claim 1, characterized in that: In the direction from the first end (101) to the second end (102), the electrical conductivity of the conductive ceramic heating element (100) gradually increases from 10S / cm-90S / cm to 0.5×10 4 S / cm-9×10 4 S / cm.

3. The conductive ceramic heating element (100) according to claim 1 or 2, characterized in that: The material of the conductive ceramic heating element (100) includes insulating ceramic material, conductive ceramic material, and conductive non-ceramic material, and the conductive non-ceramic material includes acid-resistant material; The mass content of the insulating ceramic material in the conductive ceramic heating element (100) is 65%-95%; The mass content of the conductive ceramic material in the conductive ceramic heating element (100) is 4.5%-34.5%; The mass content of the conductive non-ceramic material in the conductive ceramic heating element (100) is 0.5%-5%.

4. The conductive ceramic heating element (100) according to claim 3, characterized in that: The mass content of the conductive non-ceramic material gradually increases in a direction from the first end (101) to the second end (102); The mass content of the acid-resistant material gradually increases along the direction from the first end (101) to the second end (102).

5. The conductive ceramic heating element (100) according to claim 3, characterized in that: The conductive non-ceramic material also includes an acid-resistant material, and the mass ratio of the non-acid-resistant material to the acid-resistant material in the conductive ceramic heating element (100) is 1:(0.05-9).

6. The conductive ceramic heating element (100) according to claim 5, characterized in that: Along the direction from the first end (101) to the second end (102), the mass difference of the acid-resistant material in the conductive ceramic heating element (100) does not exceed 0.1%.

7. The conductive ceramic heating element (100) according to claim 5, characterized in that: Along the direction from the first end (101) to the second end (102), the mass content of the acid-resistant material in the conductive non-ceramic material gradually increases from 0%-10% to 10%-100%, and the mass content of the acid-resistant material gradually decreases from 90%-100% to 0%-90%.

8. The conductive ceramic heating element (100) according to claim 3, characterized in that: The material of the conductive ceramic heating element (100) further includes a sintering aid, and the mass content of the sintering aid in the conductive ceramic heating element (100) is 0.5%-3%.

9. A method for preparing a conductive ceramic heating element (100), characterized in that: include: The insulating ceramic material, the conductive ceramic material, the conductive non-ceramic material and the solvent are mixed and molded to obtain a green body, wherein the conductive non-ceramic material includes an acid-resistant material; sintering the green body to obtain a preform; The preform is etched with an acid solution to obtain a conductive ceramic heating element (100), wherein the conductive ceramic heating element (100) has a first end (101) and a second end (102) that are arranged opposite to each other, and the conductivity of the conductive ceramic heating element (100) gradually increases in a direction from the first end (101) to the second end (102).

10. The preparation method according to claim 9, characterized in that: The method of preparing an embryo body by mixing and molding the insulating ceramic material, the conductive ceramic material, the conductive non-ceramic material and the solvent comprises: The insulating ceramic material, the conductive ceramic material, the conductive non-ceramic material and the solvent are mixed, and the embryonic body is prepared by dry pressing or tape casting.

11. The preparation method according to claim 9, characterized in that: The sintering temperature is 1550° C.-1750° C., the sintering time is 0.5 h-2 h, and the sintering environment is a vacuum environment or an inert atmosphere filled with reducing gas.

12. The preparation method according to claim 9, characterized in that: The concentration of the acid solution is 0.01 mol / L-0.1 mol / L.

13. The preparation method according to claim 9, characterized in that: The method of etching the preform with acid solution comprises: The preform is placed in the acid solution for etching, and the preform is moved during etching until the preform leaves the acid solution, wherein the moving speed is 0.05 mm / min-1 mm / min.

14. An electronic cigarette (10), characterized in that: It comprises the conductive ceramic heating element (100) described in any one of claims 1 to 8 or the conductive ceramic heating element (100) prepared by the preparation method described in any one of claims 9 to 13.

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