Flexible ceramic-based electronic cigarette heating wire and preparation method thereof

Abstract

The invention relates to the technical field of electronic cigarette heating elements, in particular to a flexible ceramic-based electronic cigarette heating wire and a preparation method thereof.The flexible ceramic-based electronic cigarette heating wire comprises a zirconia ceramic fiber matrix, the zirconia ceramic fiber matrix is composed of tetragonal phase zirconia co-stabilized by 3-5 mol% of yttrium oxide and 1-2 mol% of cerium oxide, the diameter of zirconia ceramic fibers is 200-400 nm, and the grain size is 80-120 nm; the surface of the zirconia ceramic fiber matrix is covered with the metal film layer, and the metal film layer comprises a zirconium transition layer with the thickness of 2-3 nm; the iron-chromium-aluminum alloy layer comprises the following components in percentage by weight: 68 to 71 percent of iron, 22 to 24 percent of chromium, 5.5 to 6.2 percent of aluminum, 0.2 to 0.28 percent of yttrium and the balance of inevitable impurities; and the thickness of the iron-chromium-aluminum alloy layer is 300-400 nm, and the resistivity of the iron-chromium-aluminum alloy layer is 1.3-1.4 mu omega.m.

Description

Technical Field

[0001] This invention relates to the field of electronic cigarette heating element technology, specifically to flexible ceramic-based electronic cigarette heating wire and its preparation method. Background Technology

[0002] Electronic cigarettes, as a substitute for traditional cigarettes, have been widely used globally. The core component of an electronic cigarette is the heating element, whose performance directly affects the user experience, safety, and energy efficiency.

[0003] Currently, electronic cigarette heating elements mainly use metal coils (such as nickel-chromium alloy coils) or metal films as heating materials. These traditional heating elements have several drawbacks: First, metal heating elements have limited flexibility and bending cycles, making them prone to breakage after long-term use; second, metal heating elements are prone to oxidation at high temperatures, resulting in a short lifespan; third, the heat distribution of metal heating elements is uneven, affecting the heating effect; fourth, traditional metal heating elements consume a lot of energy, reducing the battery life of electronic cigarettes; and fifth, some metal materials may release harmful substances at high temperatures, posing health risks.

[0004] Ceramic materials possess excellent high-temperature stability and chemical inertness, and in recent years, research has shown their application in e-cigarette heating elements. However, traditional ceramic materials generally suffer from high brittleness and poor flexibility, failing to meet the requirements of e-cigarettes for the flexibility and bending life of heating elements. Therefore, developing an e-cigarette heating wire that combines the high-temperature stability of ceramic materials with the good electrical conductivity of metallic materials, while also possessing excellent flexibility, is of great significance for improving the performance and safety of e-cigarette products. Summary of the Invention

[0005] The purpose of this invention is to provide a flexible ceramic-based electronic cigarette heating wire and its preparation method, so as to solve the technical problems of poor flexibility, short life, uneven heat distribution and high energy consumption of electronic cigarette heating elements in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a flexible ceramic-based electronic cigarette heating wire, the flexible ceramic-based electronic cigarette heating wire comprising: a zirconia ceramic fiber matrix, the zirconia ceramic fiber matrix being composed of tetragonal phase zirconia co-stabilized with 3-5 mol% yttrium oxide and 1-2 mol% cerium oxide, the zirconia ceramic fiber having a diameter of 200-400 nm and a grain size of 80-120 nm; and a metal film layer covering the surface of the zirconia ceramic fiber matrix, the metal film layer comprising: a zirconium transition layer with a thickness of 2-3 nm; and an iron-chromium-aluminum alloy layer, the composition of the iron-chromium-aluminum alloy layer comprising, by weight percentage: 68-71% iron, 22-24% chromium, 5.5-6.2% aluminum, 0.2-0.28% yttrium, the remainder being unavoidable impurities; the thickness of the iron-chromium-aluminum alloy layer being 300-400 nm; wherein, the resistivity of the flexible ceramic-based electronic cigarette heating wire is 1.3-1.4 μΩ·m, and the temperature coefficient of resistance is 45-55 ppm / °C.

[0007] In some embodiments of the present invention, the zirconia ceramic fiber matrix further contains 0.5-1.0 wt% SiO2 and 0.2-0.28 wt% Al2O3.

[0008] In some embodiments of the present invention, the iron-chromium-aluminum alloy layer also contains trace elements, including by weight percentage: silicon 0.2-0.3%, manganese 0.1-0.15%, calcium 0.05-0.08%, and titanium 0.05-0.08%.

[0009] In some embodiments of the present invention, when the bending radius of the flexible ceramic-based electronic cigarette heating wire is 3mm, it can withstand more than 10,000 bending cycles, and the resistance change is less than 10%.

[0010] In some embodiments of the present invention, a 1-2 nm thick Al2O3 protective layer is formed on the surface of the flexible ceramic-based electronic cigarette heating wire, and the edge of the flexible ceramic-based electronic cigarette heating wire has an 8-12 μm thick alkaline earth silicate glass encapsulation layer.

[0011] Secondly, the present invention provides a method for preparing the above-mentioned flexible ceramic-based electronic cigarette heating wire, the method comprising the following steps: (1) Preparation of zirconia ceramic fiber matrix, including: a) Prepare a precursor solution comprising 20-25 wt% zirconium precursor, appropriate amounts of yttrium salt and cerium salt to provide 3-5 mol% Y2O3 and 1-2 mol% CeO2, 10-12 wt% polyvinylpyrrolidone (PVP, molecular weight about 1,300,000), and a solvent of ethanol / N,N-dimethylformamide mixture in a volume ratio of 4:1; b) Zirconia precursor fibers were prepared by electrospinning, wherein the parameters of the electrospinning process included: applied voltage of 18-22 kV, flow rate of 0.8-1.2 mL / h, distance from needle to collector of 12-15 cm, and ambient humidity of 30-40% RH. c) The zirconia precursor fiber is subjected to heat treatment, including: drying at 80°C for 12 hours, then heating to 300-500°C at a heating rate of 2°C / min and holding for 2 hours to remove organic matter, then heating to 900-1000°C at a heating rate of 3°C / min and holding for 3 hours for calcination, and finally cooling to room temperature at a cooling rate of 5°C / min. (2) Depositing a metal film layer on the surface of the zirconia ceramic fiber matrix, including: a) Surface pretreatment of the zirconia ceramic fiber matrix includes: ultrasonic cleaning, sequentially using acetone, isopropanol and deionized water for 10 minutes each; oxygen plasma treatment, power 200W, pressure 0.5Torr, time 5 minutes. b) A 2-3 nm thick zirconium transition layer was deposited on the surface of the zirconium oxide ceramic fiber matrix using high-power pulsed magnetron sputtering (HiPIMS) technology; c) A high-power pulsed magnetron sputtering technique is used to deposit an iron-chromium-aluminum alloy layer on the surface of the zirconium transition layer. The parameters of the HiPIMS technique include: background vacuum <5×10⁻⁶. -6 Torr, working pressure 3-5×10 -3 Torr, with high-purity argon (99.999%) as the working gas, a flow rate of 30-40 sccm, a substrate temperature of 250-300°C, a pulse frequency of 100-200 Hz, a duty cycle of 1-5%, and an average power density of 5-10 W / cm². 2 The deposition rate is 0.6-1.0 nm / s; (3) Post-treatment of the zirconium oxide ceramic fiber matrix with deposited metal film, including: a) Under vacuum conditions (pressure 10) -5 The zirconia ceramic fiber matrix with the deposited metal film was annealed at 350°C for 60 minutes, and then cooled to room temperature at a cooling rate of 4°C / min. b) At 300°C, under controlled oxygen partial pressure (10ppm O2 in Ar), the temperature is maintained for 20 minutes to form a 1-2nm thick Al2O3 protective layer; c) The edge of the flexible ceramic-based electronic cigarette heating wire is encapsulated using low-melting-point alkaline earth silicate glass at a temperature of 550-600°C for 10-15 minutes.

[0012] In some embodiments of the present invention, the zirconium precursor is zirconium acetate or zirconium propoxy, the yttrium salt is Y(NO3)3·6H2O, and the cerium salt is Ce(NO3)3·6H2O.

[0013] In some embodiments of the present invention, a two-step sintering process is adopted in the heat treatment process of step (1)c): initial rapid heating to 1050°C followed by extended holding at 950°C to optimize the microstructure.

[0014] In some embodiments of the present invention, in step (2)a), the surface pretreatment further includes immersing in a 1% aqueous solution of γ-aminopropyltriethoxysilane for 30 minutes and then drying at 110°C for 10 minutes to enhance the interfacial bonding strength.

[0015] Thirdly, the present invention provides an application of the flexible ceramic-based electronic cigarette heating wire in an electronic cigarette heating device. The application includes: installing the flexible ceramic-based electronic cigarette heating wire in the electronic cigarette heating device, regulating the current through the electronic cigarette control system, so that the flexible ceramic-based electronic cigarette heating wire can be heated to 200-400°C within 1 second, with a temperature uniformity of ±5%, a service life of more than 30,000 cycles under temperature cycling from room temperature to 400°C, and energy consumption reduced by 20-30% compared with traditional metal wire heating elements.

[0016] Beneficial effects of the invention: 1) The flexible ceramic-based electronic cigarette heating wire provided by the present invention combines the high-temperature stability of zirconia ceramic fiber with the good conductivity of iron-chromium-aluminum alloy. Through special multilayer film structure design and precise manufacturing process control, it achieves excellent flexibility (can withstand more than 10,000 bends with a bending radius of 3mm) and long life (more than 30,000 temperature cycles). 2) This invention uses nanoscale tetragonal zirconium oxide fibers co-stabilized by Y2O3 and CeO2 as the matrix, and SiO2 and Al2O3 as additives. Combined with precisely controlled grain size, the flexibility of ceramic fibers is significantly improved. 3) This invention employs a zirconium transition layer and an optimized FeCrAl alloy layer structure, and achieves strong bonding between the metal film layer and the ceramic substrate through HiPIMS technology, ensuring structural stability under repeated bending and thermal cycling. 4) The flexible ceramic-based electronic cigarette heating wire of the present invention has the characteristics of rapid heating performance (up to 200°C within 1 second), uniform temperature distribution (deviation <±5%) and reduced energy consumption (20-30% lower than traditional metal wire), which significantly improves the performance of electronic cigarettes. 5) The preparation method of the present invention is simple, highly controllable, and suitable for industrial production. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the embodiments.

[0018] The flexible ceramic-based electronic cigarette heating wire of the present invention comprises a zirconia ceramic fiber matrix and a metal film covering its surface. The metal film includes a zirconium transition layer in direct contact with the zirconia ceramic fiber matrix and an iron-chromium-aluminum alloy layer located on the surface of the zirconium transition layer. The zirconia ceramic fiber matrix is ​​composed of tetragonal zirconia co-stabilized with 3-5 mol% yttrium oxide and 1-2 mol% cerium oxide, and is prepared by electrospinning. The zirconium transition layer has a thickness of 2-3 nm and mainly serves to enhance the bonding between the metal layer and the ceramic matrix. The iron-chromium-aluminum alloy layer has a thickness of 300-400 nm and is mainly responsible for electrical conductivity and heating function.

[0019] The flexibility and high-temperature stability of the flexible ceramic-based electronic cigarette heating wire of this invention are mainly based on the following innovative designs: Innovative Design of Zirconia Ceramic Fiber Matrix This invention uses nano-scale zirconia ceramic fibers as the matrix, and its special design features include: 1) Stabilizing phase design: A co-stabilization strategy using 3-5 mol% yttrium oxide and 1-2 mol% cerium oxide is employed. This co-stabilization method exhibits better phase stability compared to a single stabilizer. Within the operating temperature range of 200-400°C for electronic cigarettes, the tetragonal zirconium oxide (t-ZrO2) content remains above 95%, avoiding volume changes and mechanical failures caused by monoclinic phase transitions.

[0020] 2) Nanostructure Design: Through electrospinning and precisely controlled heat treatment, the diameter of zirconia ceramic fibers is controlled within the range of 200-400 nm, and the grain size is controlled within the range of 80-120 nm. This nanoscale structure significantly improves the flexibility of the ceramic material, enabling it to withstand repeated bending without breaking.

[0021] 3) Micro-additive design: Adding 0.5-1.0wt% SiO2 and 0.2-0.28wt% Al2O3 to zirconia ceramic fibers as grain boundary pinning agents restricts grain growth and optimizes the grain boundary structure, further improving the flexibility and mechanical stability of the fibers.

[0022] The metal film layer of this invention adopts a dual-layer structure design, including a zirconium transition layer and an iron-chromium-aluminum alloy functional layer: 1) Zirconium transition layer: The 2-3nm thick zirconia transition layer is in direct contact with the zirconia ceramic fiber matrix. Due to the good chemical affinity between zirconia and the zirconia matrix, a strong interfacial bond can be formed, which greatly improves the adhesion between the metal film and the ceramic matrix.

[0023] 2) Iron-chromium-aluminum alloy layer: The 300-400nm thick iron-chromium-aluminum alloy layer is the main functional layer, responsible for conductivity and heat generation. Its composition is designed as follows: iron 68-71%, chromium 22-24%, aluminum 5.5-6.2%, and yttrium 0.2-0.28%. Chromium provides oxidation protection, aluminum forms a protective Al2O3 film at high temperatures, and yttrium enhances the adhesion and thermal cycling stability of the Al2O3 protective layer. In addition, trace elements such as silicon 0.2-0.3%, manganese 0.1-0.15%, calcium 0.05-0.08%, and titanium 0.05-0.08% are added to further optimize the ductility, oxidation resistance, and thermal stability of the alloy layer.

[0024] 3) Surface protective layer: A 1-2 nm thick Al2O3 protective layer is formed on the surface of the iron-chromium-aluminum alloy layer. By controlling the oxidation process, the self-formation of the layer further improves the oxidation resistance and chemical stability of the heating wire.

[0025] 4) Edge encapsulation: The edges of the flexible ceramic-based electronic cigarette heating wire are encapsulated with 8-12μm thick alkaline earth silicate glass to prevent edge oxidation and peeling, and extend service life.

[0026] The flexible ceramic-based electronic cigarette heating wire of the present invention achieves optimized electrical performance by precisely controlling the composition and microstructure of the iron-chromium-aluminum alloy layer: 1) Resistivity: By controlling the composition and thickness of the iron-chromium-aluminum alloy layer, the resistivity of the heating wire is controlled within the range of 1.3-1.4 μΩ·m, which meets the resistance requirements of the heating element of electronic cigarettes.

[0027] 2) Temperature coefficient: The temperature coefficient of resistance (TCR) of the heating wire is 45-55ppm / °C. This moderate TCR value can ensure that the resistance increases when the temperature rises (which is beneficial to temperature self-stabilization) without causing excessive resistance changes that would affect normal operation.

[0028] Preparation method of flexible ceramic-based electronic cigarette heating wire The preparation method of the flexible ceramic-based electronic cigarette heating wire of the present invention mainly includes three stages: preparation of zirconia ceramic fiber matrix, metal film deposition and post-treatment.

[0029] Preparation of zirconia ceramic fiber matrix: 1) Preparation of precursor solution: Dissolve 20-25 wt% of the zirconium precursor (zirconium acetate or zirconium propoxy) in a mixed solvent of ethanol / N,N-dimethylformamide at a volume ratio of 4:1. Add appropriate amounts of Y(NO3)3·6H2O and Ce(NO3)3·6H2O to provide 3-5 mol% Y2O3 and 1-2 mol% CeO2 in the final product; Add 10-12 wt% of polyvinylpyrrolidone (PVP, molecular weight approximately 1,300,000) as a polymer carrier; If SiO2 and Al2O3 need to be added, then the corresponding silicon and aluminum precursors should be added respectively; Stirring at room temperature for 12 hours yields a homogeneous and transparent precursor solution.

[0030] 2) Electrospinning process: The precursor solution is loaded into a syringe and installed on an electrospinning device; Set the electrospinning parameters as follows: apply voltage 18-22kV, flow rate 0.8-1.2mL / h, distance from needle to collector 12-15cm, and control ambient humidity at 30-40%RH; A rotating collector with a rotation speed of 500-1000 rpm is used to collect oriented nanofibers.

[0031] 3) Heat treatment process: The collected nanofibers were dried at 80°C for 12 hours to remove residual solvent; Heat to 300-500°C at a heating rate of 2°C / min and hold for 2 hours to remove organic components; The calcined zirconium oxide fibers are formed by heating to 900-1000°C at a heating rate of 3°C / min and holding at that temperature for 3 hours. Cool to room temperature at a cooling rate of 5°C / min.

[0032] In a preferred embodiment, a two-step sintering process is employed: initial rapid heating to 1050°C, followed by cooling to 950°C and extended holding time. This process helps control grain growth and optimize the microstructure.

[0033] Metal film deposition: 1) Surface pretreatment: The zirconia ceramic fiber matrix was ultrasonically cleaned by sequentially using acetone, isopropanol and deionized water for 10 minutes each. The surface was activated using oxygen plasma treatment at a power of 200W, a pressure of 0.5 Torr, and a time of 5 minutes. In a preferred embodiment, the treated fibers are immersed in a 1% aqueous solution of γ-aminopropyltriethoxysilane for 30 minutes and then dried at 110°C for 10 minutes to enhance the interfacial bonding strength.

[0034] 2) Zirconium transition layer deposition: A 2-3 nm thick zirconium transition layer was deposited on the surface of a zirconium oxide ceramic fiber matrix using high-power pulsed magnetron sputtering (HiPIMS) technology. HiPIMS parameter settings: Base vacuum < 5 × 10 -6 Torr, working pressure 3-5×10 -3 Torr, with high-purity argon (99.999%) as the working gas, a flow rate of 30-40 sccm, a substrate temperature of 250-300°C, a pulse frequency of 100-200 Hz, a duty cycle of 1-5%, and an average power density of 5-10 W / cm². 2 The deposition rate was controlled at 0.6-1.0 nm / s.

[0035] 3) Deposition of iron-chromium-aluminum alloy layer: A 300-400 nm thick iron-chromium-aluminum alloy layer was deposited on the zirconium transition layer using HiPIMS technology. The target material is made of iron-chromium-aluminum alloy (Fe: 68-71%, Cr: 22-24%, Al: 5.5-6.2%, Y: 0.2-0.28%, Si: 0.2-0.3%, Mn: 0.1-0.15%, Ca: 0.05-0.08%, Ti: 0.05-0.08%), which meets the design composition requirements. The HiPIMS parameters are the same as those for zirconium transition layer deposition, and the film thickness is controlled by adjusting the deposition time.

[0036] Post-processing 1) Annealing treatment: Under vacuum conditions (pressure 10) -5 Torr) is used to anneal the zirconium oxide ceramic fiber matrix with deposited metal film; The temperature was set to 350°C and held for 60 minutes, then cooled to room temperature at a rate of 4°C / min. The purpose of annealing is to release residual stress and optimize grain structure and film adhesion.

[0037] 2) Surface oxidation treatment: Hold at 300°C for 20 minutes under controlled oxygen partial pressure (10 ppm O2 in Ar); This process forms a 1-2 nm thick Al2O3 protective layer on the surface of the iron-chromium-aluminum alloy layer, improving its oxidation resistance and chemical stability.

[0038] 3) Edge packaging treatment: The edges of the flexible ceramic-based electronic cigarette heating wire are encapsulated using low-melting-point alkaline earth silicate glass. Encapsulation temperature 550-600°C, hold for 10-15 minutes; Edge sealing prevents edge oxidation and peeling, extending the lifespan of the heating wire.

[0039] Performance characteristics of flexible ceramic-based electronic cigarette heating wire A. Flexibility: The flexible ceramic-based electronic cigarette heating wire of the present invention can withstand more than 10,000 bending cycles with a bending radius of 3mm, and the resistance change is less than 10%, which is far superior to traditional metal heating wires (generally less than 1,000 cycles).

[0040] B. Thermal cycling stability: The flexible ceramic-based electronic cigarette heating wire of the present invention has a service life of more than 30,000 cycles under temperature cycling conditions of room temperature to 400°C, while the service life of traditional metal heating wires is generally 5,000-10,000 cycles.

[0041] C. Temperature uniformity: The flexible ceramic-based electronic cigarette heating wire of the present invention has a uniform temperature distribution under working conditions, with the deviation controlled within ±5%, while the temperature deviation of traditional metal heating wires is usually around ±15%.

[0042] D. Thermal response performance: The flexible ceramic-based electronic cigarette heating wire of the present invention can heat up from room temperature to 200-400°C within 1 second, meeting the requirements for rapid start-up of electronic cigarettes.

[0043] E. Energy efficiency: Compared with traditional metal wire heating elements, the flexible ceramic-based electronic cigarette heating wire of the present invention reduces energy consumption by 20-30%, significantly improving the battery life of electronic cigarettes.

[0044] Example 1 1) Preparation of zirconia ceramic fiber matrix: 22 wt% zirconium acetate was dissolved in a mixed solvent of ethanol / N,N-dimethylformamide with a volume ratio of 4:1. Adding Y(NO3)3·6H2O and Ce(NO3)3·6H2O provides 4 mol% Y2O3 and 1.5 mol% CeO2, respectively; Add 11 wt% polyvinylpyrrolidone (PVP, molecular weight 1,300,000); The addition of silicon and aluminum precursors provides 0.8 wt% SiO2 and 0.25 wt% Al2O3, respectively. Stirring at room temperature for 12 hours yielded a homogeneous and transparent precursor solution; Set the electrospinning parameters as follows: voltage 20kV, flow rate 1.0mL / h, needle-to-collector distance 14cm, ambient humidity 35%RH, and rotation speed 750rpm. The collected nanofibers were dried at 80°C for 12 hours; Heat to 400°C at a heating rate of 2°C / min and hold for 2 hours; Heat to 950°C at a heating rate of 3°C / min and hold for 3 hours; Cool to room temperature at a cooling rate of 5°C / min.

[0045] (2) Metal film deposition: The zirconia ceramic fiber matrix was ultrasonically cleaned by sequentially using acetone, isopropanol and deionized water for 10 minutes each. Oxygen plasma treatment was used at a power of 200W, a pressure of 0.5 Torr, and a time of 5 minutes. The treated fibers were soaked in a 1% aqueous solution of γ-aminopropyltriethoxysilane for 30 minutes, and then dried at 110°C for 10 minutes. A 2.5 nm thick zirconium transition layer was deposited on the surface of a zirconium oxide ceramic fiber matrix using HiPIMS technology. Parameter settings: background vacuum 3 × 10⁻⁶ -6 Torr, working pressure 4×10 -3 Torr, with high-purity argon (99.999%) as the working gas, a flow rate of 35 sccm, a substrate temperature of 275°C, a pulse frequency of 150 Hz, a duty cycle of 3%, and an average power density of 7.5 W / cm². 2 The deposition rate is 0.8 nm / s; A 350 nm thick iron-chromium-aluminum alloy layer was deposited on the zirconium transition layer using HiPIMS technology. The target composition was: Fe: 70%, Cr: 23%, Al: 6%, Y: 0.25%, Si: 0.28%, Mn: 0.15%, Ca: 0.07%, Ti: 0.07%, with the remainder being unavoidable impurities. The deposition parameters were the same as those for the zirconium transition layer.

[0046] (3) Post-processing: Under vacuum conditions (pressure 10) -5 The Torr was annealed at 350°C for 60 minutes, and then cooled to room temperature at a rate of 4°C / min. An Al2O3 protective layer was formed by holding the temperature at 300°C for 20 minutes under controlled oxygen partial pressure (10 ppm O2 in Ar). Edge sealing was performed using low-melting-point alkaline earth silicate glass at 580°C for 12 minutes.

[0047] Test results: The resistivity of the obtained flexible ceramic-based electronic cigarette heating wire is 1.35 μΩ·m, the temperature coefficient of resistance is 50 ppm / °C, it can withstand 12,500 bending cycles with a bending radius of 3 mm, the temperature uniformity is ±4.2%, the temperature cycle life is 32,000 cycles from room temperature to 400°C, and the heating energy consumption is reduced by 25% compared with traditional metal wires.

[0048] Example 2 (1) Preparation of zirconia ceramic fiber matrix: 24 wt% of propoxyzirconium was dissolved in a mixed solvent of ethanol and N,N-dimethylformamide with a volume ratio of 4:1. Adding Y(NO3)3·6H2O and Ce(NO3)3·6H2O provides 3 mol% Y2O3 and 2 mol% CeO2, respectively; Add 10.5 wt% polyvinylpyrrolidone (PVP, molecular weight 1,300,000); The addition of silicon and aluminum precursors provides 0.7 wt% SiO2 and 0.2 wt% Al2O3, respectively. Stirring at room temperature for 12 hours yielded a homogeneous and transparent precursor solution; Set the electrospinning parameters as follows: voltage 22kV, flow rate 0.9mL / h, needle-to-collector distance 15cm, ambient humidity 32%RH, and rotation speed 800rpm. The collected nanofibers were dried at 80°C for 12 hours; A two-step sintering process is adopted: heating to 400°C at a heating rate of 2°C / min and holding for 2 hours, then heating to 1050°C at a heating rate of 3°C / min and holding for 30 minutes, cooling to 950°C and holding for 2.5 hours, and finally cooling to room temperature at a cooling rate of 5°C / min.

[0049] (2) The metal film deposition is similar to that in Example 1, but the thickness of the iron-chromium-aluminum alloy layer is adjusted to 380 nm. The target material composition is: Fe: 68%, Cr: 24%, Al: 6.2%, Y: 0.28%, Si: 0.25%, Mn: 0.12%, Ca: 0.08%, Ti: 0.08%, with the remainder being unavoidable impurities.

[0050] (3) The post-processing process is the same as in Example 1.

[0051] Test results: The resistivity of the obtained flexible ceramic-based electronic cigarette heating wire is 1.32 μΩ·m, the temperature coefficient of resistance is 48 ppm / °C, it can withstand 14,000 bending cycles with a bending radius of 3 mm, the temperature uniformity is ±3.8%, the temperature cycle life is 34,500 cycles from room temperature to 400°C, and the heating energy consumption is reduced by 28% compared with traditional metal wires.

[0052] Example 3 Preparation of zirconia ceramic fiber matrix: 20 wt% zirconium acetate was dissolved in a mixed solvent of ethanol / N,N-dimethylformamide with a volume ratio of 4:1. Adding Y(NO3)3·6H2O and Ce(NO3)3·6H2O provides 5 mol% Y2O3 and 1 mol% CeO2, respectively; Add 12 wt% polyvinylpyrrolidone (PVP, molecular weight 1,300,000); The addition of silicon and aluminum precursors provides 1.0 wt% SiO2 and 0.28 wt% Al2O3, respectively. Stirring at room temperature for 12 hours yielded a homogeneous and transparent precursor solution; Set the electrospinning parameters as follows: voltage 18kV, flow rate 1.2mL / h, needle-to-collector distance 12cm, ambient humidity 40%RH, and rotation speed 600rpm. The collected nanofibers were dried at 80°C for 12 hours; Heat to 350°C at a heating rate of 2°C / min and hold for 2 hours, then heat to 980°C at a heating rate of 3°C / min and hold for 3.5 hours, and finally cool to room temperature at a cooling rate of 5°C / min.

[0053] (2) The metal film deposition is similar to that in Example 1, but without silane coupling agent treatment. The zirconium transition layer thickness is 2.2 nm, the iron-chromium-aluminum alloy layer thickness is 320 nm, and the target material composition is: Fe: 71%, Cr: 22%, Al: 5.5%, Y: 0.2%, Si: 0.2%, Mn: 0.1%, Ca: 0.05%, Ti: 0.05%, with the remainder being unavoidable impurities.

[0054] (3) The post-processing process is similar to that in Example 1, but the edge encapsulation temperature is adjusted to 560°C and the heat preservation time is 15 minutes.

[0055] Test results: The resistivity of the obtained flexible ceramic-based electronic cigarette heating wire is 1.38 μΩ·m, the temperature coefficient of resistance is 52 ppm / °C, it can withstand 11,200 bending cycles with a bending radius of 3 mm, the temperature uniformity is ±4.8%, the temperature cycle life is 30,500 cycles from room temperature to 400°C, and the heating energy consumption is reduced by 22% compared with traditional metal wires.

[0056] Application of flexible ceramic-based electronic cigarette heating wire in electronic cigarette heating devices, the application including: The flexible ceramic-based electronic cigarette heating wire is installed in an electronic cigarette heating device. The current is adjusted by the electronic cigarette control system, so that the flexible ceramic-based electronic cigarette heating wire can be heated to 200-400°C within 1 second. It has a temperature uniformity of ±5%, a service life of more than 30,000 cycles under temperature cycling from room temperature to 400°C, and energy consumption is reduced by 20-30% compared with traditional metal wire heating elements.

[0057] The flexible ceramic-based electronic cigarette heating wire and its preparation method provided by this invention achieve an organic combination of the high-temperature stability of ceramic materials and the good conductivity of metallic materials, while possessing excellent flexibility and bending life. Compared with traditional metal heating wires, the product of this invention has a longer service life, more uniform heating effect, and lower energy consumption, which can significantly improve the performance and user experience of electronic cigarettes. The preparation process adopted by this invention is simple and controllable, the raw materials are readily available, suitable for large-scale production, and has good industrial applicability.

[0058] In addition to its application in conventional electronic cigarette products, the flexible ceramic-based electronic cigarette heating wire of this invention can also be applied to heated tobacco products, medical atomizers, and other fields that require flexible heating elements, showing broad market prospects.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of protection of the present invention.

Claims

1. A flexible ceramic-based electronic cigarette heating wire, characterized in that, The flexible ceramic-based electronic cigarette heating wire includes: A zirconia ceramic fiber matrix, wherein the zirconia ceramic fiber matrix is ​​composed of tetragonal zirconia co-stabilized with 3-5 mol% yttrium oxide and 1-2 mol% cerium oxide, and the zirconia ceramic fibers have a diameter of 200-400 nm and a grain size of 80-120 nm; and A metal film layer covering the surface of the zirconia ceramic fiber matrix, the metal film layer comprising: Zirconium transition layer, with a thickness of 2-3 nm; and The iron-chromium-aluminum alloy layer comprises, by weight percentage: 68-71% iron, 22-24% chromium, 5.5-6.2% aluminum, 0.2-0.28% yttrium, with the remainder being unavoidable impurities; the thickness of the iron-chromium-aluminum alloy layer is 300-400 nm. The resistivity of the flexible ceramic-based electronic cigarette heating wire is 1.3-1.4 μΩ·m, and the temperature coefficient of resistance is 45-55 ppm / °C.

2. The flexible ceramic-based electronic cigarette heating wire according to claim 1, characterized in that, The zirconia ceramic fiber matrix also contains 0.5-1.0 wt% SiO2 and 0.2-0.28 wt% Al2O3.

3. The flexible ceramic-based electronic cigarette heating wire according to claim 1, characterized in that, The iron-chromium-aluminum alloy layer also contains trace elements, including by weight percentage: silicon 0.2-0.3%, manganese 0.1-0.15%, calcium 0.05-0.08%, and titanium 0.05-0.08%.

4. The flexible ceramic-based electronic cigarette heating wire according to claim 1, characterized in that, When the bending radius of the flexible ceramic-based electronic cigarette heating wire is 3mm, it can withstand more than 10,000 bending cycles, and the resistance change is less than 10%.

5. The flexible ceramic-based electronic cigarette heating wire according to claim 1, characterized in that, The surface of the flexible ceramic-based electronic cigarette heating wire is covered with a 1-2 nm thick Al2O3 protective layer, and the edge of the flexible ceramic-based electronic cigarette heating wire has an 8-12 μm thick alkaline earth silicate glass encapsulation layer.

6. A method for preparing the flexible ceramic-based electronic cigarette heating wire according to any one of claims 1-5, characterized in that, The method includes the following steps: (1) Preparation of zirconia ceramic fiber matrix, including: a) Prepare a precursor solution comprising 20-25 wt% zirconium precursor, appropriate amounts of yttrium salt and cerium salt to provide 3-5 mol% Y2O3 and 1-2 mol% CeO2, 10-12 wt% polyvinylpyrrolidone, and a solvent of ethanol / N,N-dimethylformamide mixture in a volume ratio of 4:

1. b) Zirconia precursor fibers were prepared by electrospinning, wherein the parameters of the electrospinning process included: applied voltage of 18-22 kV, flow rate of 0.8-1.2 mL / h, distance from needle to collector of 12-15 cm, and ambient humidity of 30-40% RH. c) The zirconia precursor fiber is subjected to heat treatment, including: drying at 80°C for 12 hours, then heating to 300-500°C at a heating rate of 2°C / min and holding for 2 hours to remove organic matter, then heating to 900-1000°C at a heating rate of 3°C / min and holding for 3 hours for calcination, and finally cooling to room temperature at a cooling rate of 5°C / min. (2) Depositing a metal film layer on the surface of the zirconia ceramic fiber matrix, including: a) Surface pretreatment of the zirconia ceramic fiber matrix includes: ultrasonic cleaning, sequentially using acetone, isopropanol and deionized water for 10 minutes each; oxygen plasma treatment, power 200W, pressure 0.5Torr, time 5 minutes. b) A 2-3 nm thick zirconium transition layer was deposited on the surface of the zirconium oxide ceramic fiber matrix using high-power pulsed magnetron sputtering (HiPIMS) technology; c) A high-power pulsed magnetron sputtering technique is used to deposit an iron-chromium-aluminum alloy layer on the surface of the zirconium transition layer. The parameters of the HiPIMS technique include: background vacuum <5×10⁻⁶. -6 Torr, working pressure 3-5×10 -3 Torr, with high-purity argon (99.999%) as the working gas, a flow rate of 30-40 sccm, a substrate temperature of 250-300°C, a pulse frequency of 100-200 Hz, a duty cycle of 1-5%, and an average power density of 5-10 W / cm². 2 The deposition rate is 0.6-1.0 nm / s; (3) Post-treatment of the zirconium oxide ceramic fiber matrix with deposited metal film, including: a) Under vacuum conditions (pressure 10) -5 The zirconia ceramic fiber matrix with the deposited metal film was annealed at 350°C for 60 minutes, and then cooled to room temperature at a cooling rate of 4°C / min. b) At 300°C, under controlled oxygen partial pressure (10ppm O2 in Ar), the temperature is maintained for 20 minutes to form a 1-2nm thick Al2O3 protective layer; c) The edge of the flexible ceramic-based electronic cigarette heating wire is encapsulated using low-melting-point alkaline earth silicate glass at a temperature of 550-600°C for 10-15 minutes.

7. The method according to claim 6, characterized in that, The zirconium precursor is zirconium acetate or zirconium propoxy, the yttrium salt is Y(NO3)3·6H2O, and the cerium salt is Ce(NO3)3·6H2O.

8. The method according to claim 6, characterized in that, In the heat treatment process of step (1)c), a two-step sintering process is adopted: initial rapid heating to 1050°C followed by extended holding at 950°C to optimize the microstructure.

9. The method according to claim 6, characterized in that, In step (2)a), the surface pretreatment further includes immersion in a 1% aqueous solution of γ-aminopropyltriethoxysilane for 30 minutes, followed by drying at 110°C for 10 minutes to enhance the interfacial bonding strength.

10. The application of the flexible ceramic-based electronic cigarette heating wire according to any one of claims 1-5 in an electronic cigarette heating device, characterized in that, The applications include: The flexible ceramic-based electronic cigarette heating wire is installed in an electronic cigarette heating device. The current is adjusted by the electronic cigarette control system, so that the flexible ceramic-based electronic cigarette heating wire can be heated to 200-400°C within 1 second. It has a temperature uniformity of ±5%, a service life of more than 30,000 cycles under temperature cycling from room temperature to 400°C, and energy consumption is reduced by 20-30% compared with traditional metal wire heating elements.