Oxide composite heating elements, their preparation methods, and applications

Abstract

This invention belongs to the field of heating element technology, specifically relating to oxide composite heating elements, their preparation methods, and applications. The raw materials for the oxide composite heating element include a pattern layer slurry and / or an isolation layer slurry. The pattern layer slurry raw materials include LSMO, copper oxide, a sintering aid, ethyl cellulose, and a solvent; the isolation layer slurry raw materials include GDC, ethyl cellulose, a solvent, and a dispersant. Preparation method: An isolation layer is formed on a substrate by either unprinting or screen printing the isolation layer slurry. Then, a pattern layer slurry is screen printed to form a first pattern layer. Multiple pattern layers are formed on the first pattern layer by either unprinting or continued screen printing. The printed product is then co-fired to obtain the oxide composite heating element. The oxide composite heating element can be applied to electronic heating elements or heating modules. The metal oxide of this invention has good adhesion to the substrate, resulting in a heating element with excellent electrical properties.

Description

Technical Field

[0001] This invention belongs to the field of heating element technology, specifically relating to oxide composite heating elements, their preparation methods, and applications. Background Technology

[0002] Traditional nickel-chromium alloy heating elements are prone to oxidation in high-temperature, oxygen-rich environments, which reduces their lifespan. Although ceramic encapsulation technology (such as ceramic coatings) is used, cracking of the coating may accelerate the oxidation rate of the metal core.

[0003] Compared to traditional metal heating elements (such as nickel-chromium alloys), metal oxides have good high-temperature heating potential. Electrothermal elements based on metal oxide materials are more resistant to oxidation and less prone to corrosion in air, making them suitable for long-term use in high-temperature and oxygen-rich environments.

[0004] Metal oxides can adhere to a substrate to form a heating element. Ceramic can serve as a substrate, but traditional ceramic heating devices are made by dry pressing or casting to prepare ceramic sheets, which have problems such as high porosity and poor adhesion, making them unsuitable for supporting metal oxides. Summary of the Invention

[0005] In view of this, the present invention aims to propose an oxide composite heating element, its preparation method, and its application.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] Option 1:

[0008] The oxide composite heating element comprises at least one of a pattern layer slurry and an isolation layer slurry. The pattern layer slurry comprises LSMO, copper oxide, sintering aid, ethyl cellulose, and solvent. The isolation layer slurry comprises GDC, ethyl cellulose, solvent, and dispersant.

[0009] In a preferred embodiment, the solvent comprises terpineol and / or dipropylene glycol methyl ether.

[0010] In a preferred embodiment, the sintering aid includes cerium oxide.

[0011] It should be noted that copper oxide forms a low-melting-point liquid phase during sintering, which promotes the densification of LSMO; cerium oxide can act as an oxygen buffer phase, absorbing and releasing oxygen at high temperatures, thereby regulating LSMO and maintaining the stability of the Mn valence state.

[0012] Option Two:

[0013] The aforementioned method for preparing the oxide composite heating element includes the following steps:

[0014] The raw materials for the pattern layer slurry are mixed and ground to obtain the pattern layer slurry;

[0015] The raw materials for the isolation layer slurry are mixed and ground to obtain the isolation layer slurry;

[0016] An isolation layer is formed by either not printing or screen printing an isolation layer paste on the substrate. Then, a graphic layer paste is screen printed to form the first graphic layer. On the first graphic layer, a multi-layer graphic layer is formed by either not printing or continuing to screen print graphic layer paste. The printed product is then co-fired to obtain an oxide composite heating element.

[0017] It should be noted that the above technical solutions include multiple construction forms. One is to not brush an isolation layer, with the substrate and a pattern layer forming a two-layer structure; another is to brush an isolation layer, with the substrate, isolation layer and pattern layer forming a three-layer structure; and yet another is to not brush an isolation layer, with the substrate and multiple pattern layers forming a multi-layer structure. By adding pattern layers, the conductive channels are transformed into a multi-path parallel structure, current is diverted, and single-path overheating is reduced.

[0018] A preferred technical solution, when no release slurry is printed on the substrate, co-firing includes the following steps: placing the printed product into a baking oven, setting the heating program to 1450-1470°C at a rate of 5°C / min, holding at this temperature for 2-3 hours, and then allowing it to cool naturally in the oven.

[0019] A preferred technical solution involves co-firing the following steps when screen printing the release layer paste on a substrate: placing the printed product into an oven, setting the heating program to 1250-1270°C at a rate of 5°C / min, holding at this temperature for 2-3 hours, and then allowing it to cool naturally in the oven.

[0020] It should be noted that high-temperature co-firing (such as the aforementioned 1450-1470°C) brings new problems: high energy consumption and high thermal stress. Therefore, when screen printing the release layer paste on the substrate, we try to introduce low-temperature co-firing.

[0021] The isolation layer can effectively block the interdiffusion of elements between LSMO and the substrate after long-term use; GDC has a high oxygen ion conductivity, which plays a role similar to a "buffer" during heat treatment or use; by constructing the isolation layer, a "sandwich-like" structure is formed in conjunction with the substrate and the patterning layer.

[0022] A preferred technical solution is that the printing parameters for screen printing include: the screen spacing is set to 1.9-2.1mm, the squeegee angle is 40-45°, the screen tension is 24-26N, and the screen film thickness is 25-30μm.

[0023] In a preferred embodiment, the substrate comprises degreased zirconium oxide, and the method for preparing the degreased zirconium oxide includes the following steps:

[0024] First, add paraffin wax and stearic acid. After they are completely melted, add polyoxymethylene and polyethylene and stir until a uniform melt is formed. Add zirconium oxide and dispersant to the melt in batches and slowly, and continue to extrude and mix. After mixing, cool and granulate to obtain feedstock. Inject the feedstock into a green body to obtain a green body. Then, catalytic degreasing and thermal degreasing are performed to obtain degreased zirconium oxide.

[0025] A preferred technical solution for catalytic degreasing includes the following steps: placing the green billet into a degreasing furnace, raising the furnace temperature to 100-140°C under nitrogen protection, and introducing nitric acid vapor at 100-140°C into the degreasing furnace for catalytic degreasing;

[0026] The thermal degreasing process includes the following steps: after catalytic degreasing, the sample is transferred to a sintering furnace and heated to 300°C at a rate of 1°C / min, then to 500°C at a rate of 1°C / min, and finally to 600°C at a rate of 2°C / min. After cooling, the degreased zirconia is obtained.

[0027] Option Three:

[0028] The preparation method of an electronic heating element or heating module includes the following steps:

[0029] Electrodes are printed on an oxide composite heating element using an electrode screen and electrode paste. The printed electrode product is then baked and kept warm to obtain the prepared electrode. Silver wires are then connected to the prepared electrode using manual or automated welding methods to obtain an electronic heating element or heating module. The oxide composite heating element is the aforementioned oxide composite heating element or is prepared according to the aforementioned method for preparing oxide composite heating elements.

[0030] Furthermore, without applying an isolation layer, when the substrate and a pattern layer constitute a two-layer structure, the printing thickness of the pattern layer is 0.062-0.078 μm, and the resistance after sintering is 32.8-47.3 Ω.

[0031] Furthermore, when the three-layer structure of the isolation layer, substrate, isolation layer, and pattern layer is formed, the printing thickness including the isolation layer is 0.067-0.088 μm, and the resistance after sintering is 40.1-60.5 Ω.

[0032] Furthermore, without applying an isolation layer, when the substrate and multiple pattern layers form a multi-layer structure, the printing thickness of a 2-layer pattern layer is 0.109-0.128 μm, with a resistance of 6.744-8.232 Ω after sintering. The printing thickness of a 3-layer pattern layer is 0.167-0.196 μm, with a resistance of 3.355-3.482 Ω after sintering. The printing thickness of a 4-layer pattern layer is 0.269-0.275 μm, with a resistance of 2.030-2.093 Ω after sintering. The printing thickness of a 5-layer pattern layer is 0.321-0.371 μm, with a resistance of 1.488-1.56 Ω after sintering. The printing thickness of a 6-layer pattern layer is 0.417-0.479 μm, with a resistance of 1.308-1.334 Ω after sintering.

[0033] Compared with the prior art, the advantages of the present invention are as follows:

[0034] 1. Dry pressing and sintering processes can easily lead to insufficient product density and insufficient molding precision. This invention uses injection molding and degreasing processes to prepare degreased zirconia as a substrate. Injection molding can achieve high precision and one-time molding, which helps to eliminate molding defects such as insufficient density.

[0035] Debinding is one of the key steps in injection molding. The process of removing binder can easily cause cracks, holes or carbon residue buildup. Traditional debinding often relies on pure pyrolysis, which has a slow heating rate, long cycle, and high residue rate.

[0036] This invention first introduces nitric acid vapor for catalytic degreasing, which promotes the preferential decomposition of binders such as polyoxymethylene at a lower temperature; then, it performs thermal degreasing by raising the temperature in stages to ensure that the remaining components are removed slowly; after degreasing, the matrix is ​​sintered uniformly with no carbon residue, avoiding common defects such as "black core" and "cracking" after sintering.

[0037] The substrate prepared by this invention can provide a stable support material for the entire subsequent structural layer, which facilitates subsequent screen printing, and the screen printing paste can be well bonded to the substrate.

[0038] 2. The present invention further introduces an isolation layer between the substrate and the pattern layer. Before printing LSMO, the isolation layer is first printed on the substrate to physically isolate LSMO and zirconium oxide, suppress element interdiffusion and chemical reaction at high temperature, effectively control interface reaction, reduce interface resistance loss, and improve energy conversion efficiency.

[0039] 3. The present invention also constructs a multi-layered graphic structure by screen printing layer by layer to form a stacked heating element. The multi-layered structure increases the thickness of the conductor and the cross-sectional area of ​​the current channel on a macroscopic level, which can reduce the resistance per unit volume. On a microscopic level, multiple printing and stacking help to form a denser and more continuous conductive path, reduce interface resistance, improve electron migration efficiency, and improve electronic conductivity. Detailed Implementation

[0040] The preferred embodiments of the present invention are described in detail below. However, the present invention is not limited to the specific details in the following embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0041] It should also be noted that the various specific technical features described in the following specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0042] Unless otherwise specified, the equipment and materials used in the embodiments can be readily obtained from commercial companies.

[0043] LSMO material refers to La0.7Sr0.3MnO3, a perovskite oxide material with unique physical properties.

[0044] Example 1

[0045] I. Preparation of slurry

[0046] 1. Preparation of pattern layer paste:

[0047] 80g of LSMO powder, 1.6g of copper oxide powder, 1.6g of sintering aid, 3g of ethyl cellulose, and 14.8g of solvent were placed in a planetary ball mill and wet-milled for 24 hours using zirconia balls as the grinding medium to obtain a patterned layer slurry.

[0048] The LSMO powder used was selected from Anhui Yishitong Materials Co., Ltd., with a specific surface area of ​​0.11 m². 2 / g, D50 is 23.04μm, pH is 6.28, and loose bulk density is 2.49g / cm³. 3 .

[0049] The copper oxide powder is: nano-sized copper oxide powder, D50<100nm.

[0050] The sintering aid is CeO2 sintering aid.

[0051] Solvents: terpineol and dipropylene glycol methyl ether, with a mass ratio of terpineol to dipropylene glycol methyl ether of 85:15.

[0052] 2. Preparation of electrode paste:

[0053] For low-temperature silver paste, you can choose Wuxi Dike Electronic Materials, DK92.

[0054] II. Injection and Degreasing

[0055] Mixing: Set the kneader temperature to 180-190℃. First, add 9.8g of paraffin wax and 1.2g of stearic acid. After they are completely melted, add 4.9g of polyoxymethylene and 2.4g of polyethylene, and stir until a homogeneous melt is formed. Add 58.5g of zirconium oxide powder and 0.6g of dispersant in batches slowly to the melt, continuously extruding and mixing. After mixing, cool, granulate, and form 3mm particles to obtain the final injection feed.

[0056] Injection molding: The feedstock is heated and melted, then injected into the mold cavity under high pressure. After cooling, a green body of the desired shape is obtained. The mold temperature is 80℃, and the injection pressure is 100MPa.

[0057] Catalytic degreasing: The green body is placed on a tray in a catalytic degreasing furnace, and the furnace temperature is raised to 120°C under nitrogen protection. Under nitrogen protection, 120°C nitric acid vapor is introduced into the catalytic degreasing furnace for 6 hours to complete the catalytic degreasing of the green body.

[0058] Thermal debinding: The catalytically debinded product is transferred to a sintering furnace. The temperature is increased to 300°C at a rate of 1°C / min, then to 500°C at a rate of 1°C / min, and finally to 600°C at a rate of 2°C / min. After cooling, a completely debinded brown blank is obtained, which is the debinded zirconia.

[0059] Zirconia powder can be selected from Tosoh Japan, TZ-3YS.

[0060] The dispersant is BYK-2150.

[0061] Paraffin wax: melt index is 200g / 10min.

[0062] Polyoxymethylene (POM): Molecular weight 20,000.

[0063] Polyethylene: High-density polyethylene with a molecular weight of 50,000.

[0064] III. Screen Printing and Surface Drying

[0065] The degreased zirconium oxide was used as a substrate and fixed on the printing table.

[0066] The graphic layer paste is screen-printed onto the substrate to form a graphic layer. The printing area is 15.11mm × 20.73mm. Then, it is placed in a tunnel oven or drying oven and dried at 120°C for 15 minutes.

[0067] The screen printing parameters are set as follows: screen spacing is 2.0mm; squeegee angle is 45°; screen size is 320mm×320mm; screen tension is 25N; screen mesh count is 325; and screen film thickness is 30μm.

[0068] IV. Co-firing

[0069] Place the printed product into a high-temperature baking oven. Set the heating program to 1450-1470°C at a rate of 5°C / min. Hold at this temperature for 2-3 hours. Allow to cool naturally in the oven.

[0070] V. Printed Electrode and Soldering Silver Wire

[0071] Remove the co-fired heating element. Using an electrode stencil and electrode paste, print electrode pads on the pattern layer. Place the electrode-printed product into a preheated oven and bake at 850°C for 10-15 minutes.

[0072] On the prepared electrode, silver wires are connected by manual or automated welding. The silver wires can be coated with silver paste, which is not a key factor affecting the results. Commercially available products can be purchased, such as silver paste coated with silver wires supplied by Shanghai Shuxin Company.

[0073] Example 2

[0074] In Example 1, co-firing LSMO and zirconium oxide at a high temperature of 1450-1470°C may result in a chemical reaction at the interface between the two, forming an insulating phase with high resistivity. This interface reaction layer will: increase the interface resistance; affect the current restart, leading to a decrease in heating efficiency, or even failure of the heating element.

[0075] Therefore, an improved technical solution is provided: before printing LSMO, an isolation layer is first printed on the zirconium oxide substrate to physically isolate LSMO and zirconium oxide, thereby suppressing element interdiffusion and chemical reactions at high temperatures.

[0076] The specific steps are as follows:

[0077] I. Preparation of slurry

[0078] 1. Preparation of the isolation layer slurry:

[0079] 68g of GDC powder, 3g of ethyl cellulose, 28g of terpineol, and 0.8g of dispersant were placed in a planetary ball mill and wet-milled for 16 hours using zirconia balls as the grinding media to obtain a separating layer slurry. This process ensures that the GDC particles are fully dispersed, forming a uniform, stable slurry with suitable viscosity.

[0080] The GDC powder is gadolinium-doped cerium dioxide with a D50 of <1 μm. The dispersant is Pluronic® F-127.

[0081] 2. Preparation of pattern layer slurry:

[0082] 80g of LSMO powder, 1.6g of copper oxide powder, 1.6g of sintering aid, 3g of ethyl cellulose, and 14.8g of terpineol were placed in a planetary ball mill and wet-milled for 24 hours using zirconia balls as the grinding medium to obtain a patterned layer slurry.

[0083] The LSMO powder used was selected from Anhui Yishitong Materials Co., Ltd., with a specific surface area of ​​0.11 m². 2 / g, D50 is 23.04μm, pH is 6.28, and loose bulk density is 2.49g / cm³. 3 .

[0084] The copper oxide powder is: nano-sized copper oxide powder, D50<100nm.

[0085] The sintering aid is CeO2 sintering aid.

[0086] 3. Preparation of electrode paste:

[0087] For low-temperature silver paste, you can choose Wuxi Dike Electronic Materials, DK92.

[0088] II. Injection and Degreasing

[0089] Mixing: Set the kneader temperature to 180-190℃. First, add 9.8g of paraffin wax and 1.2g of stearic acid. After they are completely melted, add 4.9g of polyoxymethylene and 2.4g of polyethylene, and stir until a homogeneous melt is formed. Add 58.5g of zirconium oxide powder and 0.6g of dispersant in batches slowly to the melt, continuously extruding and mixing. After mixing, cool, granulate, and form 3mm particles to obtain the final injection feed.

[0090] Injection molding: The feedstock is heated and melted, then injected into the mold cavity under high pressure. After cooling, a green body of the desired shape is obtained. The mold temperature is 80℃, and the injection pressure is 100MPa.

[0091] Catalytic degreasing: The green body is placed on a tray in a catalytic degreasing furnace, and the furnace temperature is raised to 120°C under nitrogen protection. Under nitrogen protection, 120°C nitric acid vapor is introduced into the catalytic degreasing furnace for 6 hours to complete the catalytic degreasing of the green body.

[0092] Thermal debinding: The catalytically debinded product is transferred to a sintering furnace. The temperature is increased to 300°C at a rate of 1°C / min, then to 500°C at a rate of 1°C / min, and finally to 600°C at a rate of 2°C / min. After cooling, a completely debinded brown blank is obtained, which is the debinded zirconia.

[0093] Zirconia powder can be selected from Tosoh Japan, TZ-3YS.

[0094] The dispersant is BYK-2150.

[0095] Paraffin wax: melt index is 200g / 10min.

[0096] Polyoxymethylene (POM): Molecular weight 20,000.

[0097] Polyethylene: High-density polyethylene with a molecular weight of 50,000.

[0098] III. Screen Printing and Surface Drying

[0099] The degreased zirconium oxide was used as a substrate and fixed on the printing table.

[0100] The release slurry is screen-printed onto the substrate to form a release layer. The substrate is then placed in a tunnel oven or drying oven and dried at 120°C for 15 minutes.

[0101] After drying, the graphic layer paste is screen-printed onto the substrate to form a graphic layer on the release liner. The printing area is 15.11 mm × 20.73 mm. Then, it is placed in a tunnel oven or drying oven and dried at 120°C for 15 minutes.

[0102] The screen printing parameters are set as follows: screen spacing is 2.0mm; squeegee angle is 45°; screen size is 320mm×320mm; screen tension is 25N; screen mesh count is 325; and screen film thickness is 30μm.

[0103] IV. Low-temperature co-firing

[0104] Place the printed product into a high-temperature baking oven. Set the heating program to 1250-1270°C at a rate of 5°C / min. Hold at this temperature for 2-3 hours. Allow to cool naturally in the oven.

[0105] V. Printed Electrode and Soldering Silver Wire

[0106] Remove the heating element after low-temperature co-firing. Using an electrode stencil and electrode paste, print electrode pads on the pattern layer. Place the electrode-printed product into a preheating oven and bake at 850°C for 10-15 minutes.

[0107] On the prepared electrode, silver wires are connected by manual or automated welding. The silver wires can be coated with silver paste, which is not a key factor affecting the results. Commercially available products can be purchased, such as silver paste coated with silver wires supplied by Shanghai Shuxin Company.

[0108] As can be seen from the above, both Example 1 and Example 2 only printed one graphic layer. The following examines the number of graphic layers printed:

[0109] Example 3

[0110] Unlike Example 1, two graphic layers are printed. The specific steps are as follows:

[0111] III. Screen Printing and Surface Drying

[0112] The degreased zirconium oxide was used as a substrate and fixed on the printing table.

[0113] The graphic layer paste is screen-printed onto the substrate to form a graphic layer. Then, it is placed in a tunnel oven or drying oven and dried at 120°C for 15 minutes.

[0114] After drying, the graphic layer paste is screen-printed onto the first graphic layer to form the second graphic layer.

[0115] The screen printing parameters are set as follows: screen spacing is 2.0mm; squeegee angle is 45°; screen size is 320mm×320mm; screen tension is 25N; screen mesh count is 325; and screen film thickness is 30μm.

[0116] The rest is the same as in Example 1.

[0117] Following the method of Example 3, in Example 4, three graphic layers are printed, that is, graphic layer paste is screen printed on the second graphic layer to form the third graphic layer.

[0118] The same configuration is applied sequentially to Example 5 (4 graphic layers), Example 6 (5 graphic layers), and Example 7 (6 graphic layers).

[0119] The performance of the products from Examples 1-7 was tested, and the results are shown in Table 1. In Example 2, the printing thickness includes the thickness of the insulating layer, which is 10 μm. Regarding conductivity, it can be calculated as follows: printing length is the current path length, printing width × printing thickness is the conductor cross-sectional area, and conductivity = current path length / (resistance after sintering × conductor cross-sectional area). The results are shown in Table 2.

[0120] Table 1

[0121]

[0122] Table 2

[0123]

[0124] analyze:

[0125] Example 1 demonstrates that the present invention successfully fabricates a heating element with a ceramic substrate supporting a metal oxide using the process described in this application. The zirconia substrate prepared by the present invention through injection molding and debinding processes provides a stable supporting material for the entire subsequent structural layer, facilitating subsequent screen printing. The screen-printed paste bonds well with the substrate. Compared to other embodiments, Example 1 uses the simplest process, making it suitable for low-voltage, low-current applications, such as current-limiting scenarios.

[0126] Regarding energy efficiency, the "temperature / power" ratio is calculated based on a 5V point. For Example 1, it is 66 / (5×0.16) = 82.5℃ / W; for Example 2, it is 85 / (5×0.175) ≈ 97℃ / W; and for Example 3, it is 265 / (5×1.156) ≈ 46℃ / W. Calculations and comparisons are then performed in this manner. Example 2 has a higher temperature rise per unit power and better energy efficiency. The isolation layer effectively suppresses the formation of the LSMO insulating phase, reduces interface resistance loss, and improves energy conversion efficiency.

[0127] Regarding the co-firing process, Example 2 uses a low-temperature co-firing process, which saves energy compared to the high-temperature route of 1450-1470℃ used in the other examples.

[0128] Compared to Embodiments 1 and 2, which have a single graphic layer, Embodiments 3-7 achieve higher power and higher extreme temperatures under a fixed low voltage. This can be compared by calculating the "power / temperature" ratio. For example, using a 5V point, the "power / temperature" ratio is (5×0.16) / 66=0.012W / ℃ for Embodiment 1, (5×0.175) / 85≈0.010W / ℃ for Embodiment 2, (5×1.156) / 265≈0.022W / ℃ for Embodiment 3, and (5×2.145) / 395≈0.027W / ℃ for Embodiment 4. And so on. Embodiments 3-7 can significantly increase power and achieve higher temperatures at the same 5V. When applied to high-temperature or rapid hot-charging applications, Embodiments 3-7 are more suitable.

[0129] Furthermore, Examples 3-7 all exhibit high electronic conductivity, with Examples 3-7 approaching metallic levels, reaching 10. 3 With a conductivity of S / cm or higher, it is suitable for heating via the Joule effect. Examples 3-6: As the number of layers and thickness increase, the conductivity significantly improves, indicating that multilayer thick film structures can effectively improve the quality and connectivity of current conduction paths; Example 7 shows a decrease: too many layers will affect the conductivity. The conductivity of Example 2 is lower than that of Example 1: This indicates that although the energy efficiency is improved after introducing the isolation layer, the overall conductivity will decrease.

[0130] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an oxide composite heating element, characterized in that, Includes the following steps: The raw materials for the pattern layer slurry are mixed and ground to obtain the pattern layer slurry; The raw materials for the isolation layer slurry are mixed and ground to obtain the isolation layer slurry; An isolation layer is formed by either not printing or screen printing an isolation layer paste on the substrate. Then, a graphic layer paste is screen printed to form the first graphic layer. On the first graphic layer, a multi-layer graphic layer is formed by either not printing or continuing to screen print graphic layer paste. The printed product is then co-fired to obtain an oxide composite heating element. The raw materials for the pattern layer slurry include LSMO, copper oxide, sintering aid, ethyl cellulose, and solvent; the raw materials for the isolation layer slurry include GDC, ethyl cellulose, solvent, and dispersant. The substrate comprises degreased zirconium oxide, and the method for preparing the degreased zirconium oxide includes the following steps: First, add paraffin wax and stearic acid. After they are completely melted, add polyoxymethylene and polyethylene and stir until a uniform melt is formed. Add zirconium oxide and dispersant to the melt in batches and slowly, and continue to extrude and mix. After mixing, cool and granulate to obtain feedstock. Inject the feedstock into a green body to obtain a green body. Then, catalytic degreasing and thermal degreasing are performed to obtain degreased zirconium oxide.

2. The method for preparing the oxide composite heating element according to claim 1, characterized in that, Solvents include terpineol and / or dipropylene glycol methyl ether.

3. The method for preparing the oxide composite heating element according to claim 1, characterized in that, Sintering aids include cerium oxide.

4. The method for preparing the oxide composite heating element according to claim 1, characterized in that, When no release slurry is printed on the substrate, co-firing includes the following steps: placing the printed product into an oven, setting the heating program to 1450-1470°C at a rate of 5°C / min, holding at this temperature for 2-3 hours, and then allowing it to cool naturally in the oven.

5. The method for preparing the oxide composite heating element according to claim 1, characterized in that, When screen printing the release layer paste on the substrate, co-firing includes the following steps: placing the printed product into the baking oven, setting the heating program to 1250-1270°C at a rate of 5°C / min, holding at this temperature for 2-3 hours, and then allowing it to cool naturally in the oven.

6. The method for preparing the oxide composite heating element according to claim 1, characterized in that, The printing parameters for screen printing include: screen spacing of 1.9-2.1mm, squeegee angle of 40-45°, screen tension of 24-26N, and screen film thickness of 25-30μm.

7. The method for preparing the oxide composite heating element according to claim 1, characterized in that, Catalytic degreasing includes the following steps: placing the green billet into a degreasing furnace, raising the furnace temperature to 100-140℃ under nitrogen protection, and introducing nitric acid vapor at 100-140℃ into the degreasing furnace for catalytic degreasing; The thermal degreasing process includes the following steps: after catalytic degreasing, the sample is transferred to a sintering furnace and heated to 300°C at a rate of 1°C / min, then to 500°C at a rate of 1°C / min, and finally to 600°C at a rate of 2°C / min. After cooling, the degreased zirconia is obtained.

8. An electronic heating element or heating module, characterized in that, Its preparation method includes the following steps: Electrodes are printed on an oxide composite heating element using an electrode screen and electrode paste. The printed electrode product is then baked and kept warm to obtain the prepared electrode. Silver wires are then connected to the prepared electrode using manual or automated welding methods to obtain an electronic heating element or heating module. The oxide composite heating element is prepared according to the preparation method of the oxide composite heating element according to any one of claims 1-7.

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