Barium titanium-based ferroelectric thick film and preparation method thereof

Abstract

The present invention relates to a barium-titanium-based ferroelectric thick film and a preparation method thereof. The preparation method comprises: 1) preparing a dilute and concentrated solution of a barium precursor and a dilute and concentrated solution of a titanium precursor, mixing and stirring the dilute barium and titanium precursor solutions and aging them to obtain a dilute gel, and mixing and stirring the concentrated barium and titanium precursor solutions and aging them to obtain a concentrated gel; 2) spin-coating the dilute gel on a substrate multiple times, drying and heating after each spin-coating, obtaining a dilute sol three-dimensional mesh adhesion layer and sintering to obtain a first-stage substrate; 3) spin-coating the thick gel on the first-stage substrate multiple times, drying and heating after each spin-coating, obtaining a thick sol-filled viscous adhesion layer and sintering to obtain a second-stage substrate; 4) annealing the second-stage substrate to obtain a barium-titanium-based ferroelectric thick film. Compared with the prior art, the ferroelectric film obtained by the present invention has a thickness of 150-250 μm, which is better than other ferroelectric films with poor density at present, meaning that a greater ferroelectric effect may be produced.

Description

Technical Field

[0001] The invention belongs to the technical field of film material preparation, and relates to a barium-titanium-based ferroelectric thick film and a preparation method thereof. Background Art

[0002] Ferroelectric thin-film devices have become a hot topic in device fabrication due to their widespread applications in energy storage and conversion, nonvolatile memory, and micro-nano devices. However, traditional thin-film devices suffer from poor mechanical strength and durability, as well as limited integration capabilities. As an alternative to ferroelectric thin-film devices, the fabrication of large-scale ferroelectric thick films through specialized processes has become an effective approach to addressing this thin-film shortage.

[0003] Among the numerous methods for fabricating membrane devices, the sol-gel method, based on chemical reaction principles, allows precise control of ion size and morphology, reducing the particle size of the coating material within the device. Furthermore, by exploiting the fact that the gel prepared by the sol-gel method requires repeated heat treatment during heating, this method significantly reduces surface voids on the membrane device, allowing for the production of uniform ferroelectric films through thermal cycling and secondary sintering. However, most membrane devices produced using this method are typically less than 100 μm thick, exhibit numerous pores, low density, poor dielectric properties, and increased leakage current, hindering widespread application.

[0004] Currently, most sol-gel-based thick film fabrication studies use multilayer metal-oxide-silicon substrates, such as Pt (100nm) / Ti (30nm) / SiO2 (500nm) / Si (500mm) silicon wafer substrates. The high cost of substrates and the difficulty of electrode preparation based on these micro-nanofilm fabrication methods limit their application. Therefore, there is an urgent need to develop a method for fabricating lead-free ferroelectric thick films on pure metal substrates that can increase film thickness and reduce production costs. Summary of the Invention

[0005] The purpose of the present invention is to provide a barium-titanium-based ferroelectric thick film and a preparation method thereof, which can solve the problems of film surface cracking, uneven coating and insufficient thickness in traditional preparation methods.

[0006] The preparation method provided by the present invention mainly includes: preparation of composite precursor solution sol, anti-cracking and hydrolysis inhibition chemical treatment, 99.99% platinum base texture adaptive dilute sol three-dimensional network adhesion layer, dripping thick sol filling viscous bonding layer, secondary sintering to form a composite thick film structure, and annealing treatment to shape the composite thick film.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] A first aspect of the present invention provides a method for preparing a barium-titanium-based ferroelectric thick film, the method comprising the following steps:

[0009] 1) preparing a dilute barium precursor solution and a concentrated barium precursor solution containing a barium source and a hydrolysis inhibitor, and a dilute titanium precursor solution and a concentrated titanium precursor solution containing a titanium source and a hydrolysis inhibitor, mixing the dilute barium precursor solution and the dilute titanium precursor solution, adding an anti-cracking agent and aging to obtain a composite precursor dilute gel, mixing the concentrated barium precursor solution and the concentrated titanium precursor solution, adding an anti-cracking solvent and aging to obtain a composite precursor concentrated gel;

[0010] 2) Spin coating the composite precursor dilute gel on the substrate multiple times, drying and heating after each spin coating to obtain a dilute sol three-dimensional network adhesion layer, and sintering it once to obtain a first-stage substrate;

[0011] 3) Spin coating the thick gel on the first-stage substrate in step 2) multiple times, drying and heating after each spin coating to obtain a thick sol-filled viscous bonding layer, and sintering the layer twice to obtain a second-stage substrate;

[0012] 4) Annealing the second-stage substrate in step 3) to obtain a barium-titanium-based ferroelectric thick film.

[0013] Furthermore, in step 1), in the dilute barium precursor solution, the feed ratio of the barium source, the solvent, and the hydrolysis inhibitor is (5-6) g: (20-30) mL: (6-8) mL, and in the concentrated barium precursor solution, the feed ratio of the barium source, the solvent, and the hydrolysis inhibitor is (5-6) g: (18-24) mL: (6-8) mL;

[0014] In the titanium precursor dilute solution, the feed ratio of the titanium source, the solvent, and the hydrolysis inhibitor is (5-7) mL: (25-35) mL: (6-8) mL. In the titanium precursor concentrated solution, the feed ratio of the titanium source, the solvent, and the hydrolysis inhibitor is (5-7) mL: (20-28) mL: (6-8) mL.

[0015] The volume ratio of the dilute barium precursor solution or the concentrated barium precursor solution to the anti-cracking agent is 1:(0.17-0.2);

[0016] In the composite precursor dilute gel and the composite precursor concentrated gel, the molar ratio of the barium element to the titanium element is 1:(1-2).

[0017] Further preferably, in the dilute titanium precursor solution, the feed ratio of the titanium source, solvent and hydrolysis inhibitor is 5.11 g:25 mL:7 mL; in the concentrated barium precursor solution, the feed ratio of the barium source, solvent and hydrolysis inhibitor is 5.11 g:20 mL:7 mL.

[0018] Further preferably, in the dilute titanium precursor solution, the feed ratio of the titanium source, solvent and hydrolysis inhibitor is 6.81 mL:30 mL:7 mL; in the concentrated titanium precursor solution, the feed ratio of the titanium source, solvent and hydrolysis inhibitor is 6.81 mL:25 mL:7 mL.

[0019] In order to prevent hydrolysis, it is necessary to add complexing agents or high molecular compounds and other hydrolysis inhibitors. In order to prevent cracking when preparing thick films, it is necessary to add anti-cracking solvents such as soluble polymerizers or colloidal stabilizers.

[0020] Furthermore, the preparation method of the dilute barium precursor solution or the concentrated barium precursor solution is as follows: mixing a barium source and a solvent, stirring once and twice, and then adding a hydrolysis inhibitor to obtain the dilute barium precursor solution or the concentrated barium precursor solution;

[0021] During the first stirring, the stirring temperature is 55-65°C, and during the second stirring, the stirring temperature is 75-85°C.

[0022] Furthermore, the barium source is Ba(CH3COO)2, and the titanium source is C 16 H 36 O4Ti, and the solvent is CH3COOH.

[0023] Furthermore, in step 1), the hydrolysis inhibitor is selected from any one of ethylene glycol monoethyl ether, ethylenediaminetetraacetic acid or citric acid; the anti-cracking agent is selected from any one of acetylacetone, ethylene carbonate or polyol; during the stirring, the stirring temperature is 75-85°C; during the aging, the aging temperature is 26-30°C, and the aging time is 24-36h.

[0024] Furthermore, in step 2), the substrate is a platinum substrate or an aluminum substrate.

[0025] Furthermore, in step 2), the substrate is a pure metal substrate.

[0026] Furthermore, in step 2), the prepared composite precursor dilute gel is spin-coated onto a 99.99% platinum substrate to form a three-dimensional network-like adhesion layer of a certain thickness. Subsequently, the film undergoes a thermal cycle, i.e., a cyclic drying and heating operation, to evaporate the solvent and remove residual organic matter. A sintering step then eliminates internal stress in the film, reduces cracking and deformation, and promotes the initial formation of a crystalline phase.

[0027] Furthermore, in step 2), in the spin coating of the composite precursor dilute gel, the spin coating number is 5-6 times, the spin coating speed is 4000-5000RPM, and the spin coating time is 30s; in the drying treatment, the drying temperature is 110-130°C, the drying time is 2-4min, and the drying atmosphere is air or oxygen; in the heating treatment, the heating temperature is 380-410°C, the heating time is 1-2min, and the heating atmosphere is air or oxygen; in the primary sintering, the sintering temperature is 790-810°C, the sintering time is 55-70min, and the sintering atmosphere is air or oxygen.

[0028] Furthermore, in step 3), the thick gel is dripped onto the first-stage substrate, and a certain thickness of viscous bonding layer is filled on the basis of the three-dimensional mesh adhesion layer. The method of combining an adaptive composite mesh layered structure and a viscous filler is adopted to ensure that the contact angle between the bonding interface and the coating and the dripping pressure are in the optimal state of dynamic pressure control, which greatly improves the density of the thick film. Similarly, after thermal cycling treatment (drying treatment and heating treatment), secondary sintering is carried out to further promote the formation of the crystalline phase. Finally, an annealing operation is performed to promote grain growth and improve crystallinity.

[0029] Furthermore, in step 3), in the spin coating of the thick gel, the number of spin coating times is 5-6 times, the spin coating speed is 4000-5000RPM, and the spin coating time is 30s; in the drying treatment, the drying temperature is 110-130°C, the drying time is 2-4min, and the drying atmosphere is air or oxygen; in the heating treatment, the heating temperature is 380-410°C, the heating time is 1-2min, and the heating atmosphere is air or oxygen; in the secondary sintering, the sintering temperature is 790-810°C, the sintering time is 55-70min, and the sintering atmosphere is air or oxygen.

[0030] Furthermore, the spin coating acceleration is 1000 RPM / s. Too low a spin speed will result in the prepared gel not being able to completely and evenly cover the substrate surface, while too high a spin speed will cause the gel on the substrate surface to splash and leave too little residual gel.

[0031] Furthermore, in step 2) and step 3), spin coating is performed on a spin coater, and drying is performed on a magnetic rotary heating table; heating treatment, primary sintering and secondary sintering are performed in a muffle furnace.

[0032] Furthermore, in step 4), in the annealing treatment, the annealing temperature is 950-1100° C., the annealing time is 290-310 min, and the annealing atmosphere is air or oxygen.

[0033] Furthermore, in step 2), the thickness of the dilute sol three-dimensional network adhesion layer is 100-200 μm; in step 3), the thickness of the thick sol-filled viscous adhesion layer is 200-300 μm; in step 4), the thickness of the barium titanium-based ferroelectric thick film is 150-250 μm.

[0034] A second aspect of the present invention provides a barium-titanium-based ferroelectric thick film, which is manufactured using the above-mentioned preparation method.

[0035] Furthermore, the thickness of the barium titanium-based ferroelectric thick film is 150-250 μm.

[0036] The preparation method of the present invention is divided into two stages, including mixing of core reactants, a crack-preventing solvent, and a hydrolysis-inhibiting solvent, aging, spin coating, drying, heating, sintering, and finally annealing. A composite precursor solution sol is prepared in both stages, and a thin composite precursor gel and a thick composite precursor gel are prepared according to different ratios. Specifically, a metal alkoxide or an inorganic salt is dissolved in a solvent as a precursor to undergo a polycondensation reaction. The reaction products aggregate into nanometer-sized particles to form a sol, which is then aged to form a gel.

[0037] Compared with the prior art, the present invention has the following characteristics:

[0038] 1) The ferroelectric film obtained by the present invention has a thickness of 150-250 μm, which is superior to other currently available ferroelectric films with poor density, indicating the potential for a greater ferroelectric effect. Furthermore, the secondary sintering doubles the film thickness and densifies the surface of the prepared film, resolving the problem of surface cracking that prevents large-area coating.

[0039] 2) The ferroelectric thick film produced by the present invention using a pure metal (such as platinum or aluminum) as a substrate has lower cost, simpler processing, and better thermal conductivity than existing substrates applicable to phase-change ferroelectrics. Furthermore, the metal plating on the currently used silicon wafer substrate can only be processed into a planar structure due to the material limitations of the substrate itself, which means that the thick film has greater application potential than existing thin films.

[0040] 3) The membrane preparation process used in the present invention mainly requires equipment such as a muffle furnace, a balance, a magnetic rotary heating table, a spin coater, and a pyroelectric energy conversion experimental platform. Expensive equipment is not required, and the required raw materials are readily available, resulting in a low cost for membrane production.

[0041] 4) The thick film device prepared by the present invention has good flexibility. When subjected to external forces, the thick film material can bend, fold, twist, and other deformations without breaking, and has high practical prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1This is a flow chart of the method for preparing a lead-free ferroelectric thick film on a pure metal substrate according to the present invention;

[0043] Figure 2 Schematic diagram of the method for preparing a lead-free ferroelectric thick film on a pure metal substrate according to the present invention;

[0044] Figure 3 Schematic diagram of the textured adaptive dilute sol mesh attachment layer and the drip-coated thick sol filling bonding layer in the present invention;

[0045] Figure 4 is the XRD diffraction pattern of the BaTi2O5 ferroelectric thick film prepared in Example 1;

[0046] Figure 5 is a scanning electron microscope image of the BaTi2O5 ferroelectric thick film prepared in Example 1;

[0047] Figure 6 This is a scanning electron microscope image of the edge of the BaTi2O5 ferroelectric thick film prepared in Example 1;

[0048] Figure 7 This is the piezoelectric force microscope hysteresis loop spectrum of the BaTi2O5 ferroelectric thick film prepared in Example 1;

[0049] Figure 8 The XRD diffraction pattern of the BaTiO3 ferroelectric thick film prepared in Example 2;

[0050] Figure 9 This is a scanning electron microscope image of the edge of the BaTiO3 ferroelectric thick film prepared in Example 2;

[0051] Figure 10 This is the piezoelectric force microscope hysteresis loop spectrum of the BaTiO3 ferroelectric thick film prepared in Example 2. DETAILED DESCRIPTION

[0052] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0053] In the following examples, unless otherwise specified, raw materials, reagents or processing techniques are all conventional commercially available products or conventional processing techniques in the art.

[0054] In the following examples, barium titanium based ferroelectric thick films were prepared, such as Figure 1The figure shows a flow chart of a method for preparing a lead-free ferroelectric thick film on a pure metal substrate, which includes preparation of a composite precursor solution sol, chemical treatment to prevent cracking and inhibit hydrolysis, texture-adaptive dilute sol mesh adhesion layer, dripping of a thick sol filling bonding layer, secondary sintering of a composite thick film structure, and annealing treatment to shape the composite thick film to obtain the final thick film product. Figure 2 This is a schematic diagram of the preparation method of pure metal substrate lead-free ferroelectric thick film in the present invention. High-quality BaTi2O5 ferroelectric thick film and BaTiO3 ferroelectric thick film are obtained by texturing an adaptive dilute sol three-dimensional network adhesion layer on a 99.99% platinum substrate, dripping a thick sol to fill the viscous bonding layer, and secondary sintering to form a composite thick film structure.

[0055] The following are more detailed implementation cases, which further illustrate the technical solutions of the present invention and the technical effects that can be obtained.

[0056] Example 1:

[0057] A barium titanium-based ferroelectric thick film——BaTi2O5 ferroelectric thick film

[0058] The preparation method thereof comprises:

[0059] (1) Preparation of composite precursor dilute gel and composite precursor concentrated gel:

[0060] The preparation method of composite precursor dilute gel is as follows: according to the chemical formula BaTi2O5, weigh Ba(CH3COO)2 (99.99%), C 16 H 36 O4Ti (>=97.00%) and CH3COOH (>99.50%) raw materials, Ba(CH3COO)2 and CH3COOH are mixed in a ratio of about 1:5, 5.11g of Ba(CH3COO)2 is added to 25mL of CH3COOH and stirred at 60℃ for one time until the solution is clear, and then stirred twice at 80℃ to completely dissolve Ba(CH3COO)2. After cooling to room temperature, 7mL of ethylene glycol monoethyl ether (C4H 10 O2) to prepare a dilute barium precursor solution. Similarly, C 16 H 36 O4Ti and CH3COOH were mixed in a ratio of about 1:5, and 6.81 mL of C 16 H 36 O4Ti was added to 30.00 mL of CH3COOH, and then 7 mL of C4H 10O2 is added to form a dilute titanium precursor solution. After obtaining the two dilute precursor solutions, the dilute barium precursor solution and the dilute titanium precursor solution are mixed at a molar ratio of Ba:Ti = 1:2 and continuously stirred at 80°C to obtain a transparent, uniform composite precursor solution. 6mL of acetylacetone is then added to the composite precursor solution to control viscosity and prevent membrane rupture. The composite precursor gel is then formed after aging at 28°C for 24-36 hours.

[0061] The only difference between the preparation method of the composite precursor concentrated gel and the preparation method of the composite precursor dilute gel is that Ba(CH3COO)2 and CH3COOH are mixed in a ratio of about 1:4. Specifically, 5.11 g of Ba(CH3COO)2 is added to 20 mL of CH3COOH and stirred at 60 ° C until the solution is clear. Then, it is stirred twice at 80 ° C to completely dissolve Ba(CH3COO)2. After cooling to room temperature, 7 mL of ethylene glycol monoethyl ether (C4H 10 O2) to prepare a dilute barium precursor solution. Similarly, C 16 H 36 O4Ti and CH3COOH were mixed in a ratio of about 1:4, and 6.81 mL of C 16 H 36 O4Ti was added to 25.00 mL of CH3COOH, and then 7 mL of C4H 10 O2, forming a dilute titanium precursor solution. 16 H 36 O4Ti and CH3COOH were mixed in a ratio of 1:4, and the amount of the corresponding substances added was changed accordingly. The remaining steps were the same as the above-mentioned composite precursor dilute gel preparation method.

[0062] (2) Texture-adaptive dilute sol three-dimensional network attachment layer

[0063] Figure 3Schematic diagram of the textured adaptive dilute sol mesh adhesion layer and the drip-coated thick sol filling bonding layer. The composite precursor dilute gel prepared in step (1) is dropped onto a 99.99% platinum substrate adsorbed by a spin coater. The spin coating speed is set to 4000 to 5000 RPM, the acceleration is 1000 RPM / s, and the spin coating time is 30 seconds. The gel film is deposited by spin coating. The gel spin coating operation is as follows: After taking an appropriate amount of dilute gel with a dropper, it is dropped on the center of the substrate and slowly spread until the substrate is completely covered. Then the spin coater is started and a film is obtained after spin coating. Each layer of the film is then subjected to a thermal cycle treatment, that is, a cyclic drying and heating operation is performed to evaporate the solvent and remove residual organic matter. Specifically, it is placed on a magnetic rotating heating table and dried at 120°C in an air atmosphere for 3 minutes to evaporate the solvent. It is then placed in a muffle furnace and heated to 400°C for 2 minutes. The heating atmosphere is air to remove residual organic matter. Repeat the gel spin coating, drying, and heating steps 5-6 times to obtain the first-stage 5-6-layer film. This results in a 140μm-thick, 3D mesh-like layer with an adaptive surface texture formed on a 99.99% platinum substrate. This layer is then sintered once in a muffle furnace at 800°C for one hour to initially form a crystalline phase, resulting in the first-stage, preliminary finished product, designated the first-stage substrate.

[0064] (3) Drip coating of thick sol to fill the viscous bonding layer

[0065] The composite precursor concentrated gel prepared in step (1) is dropped onto the first-stage substrate obtained in step (2), and the spin coating speed is set to 4000 to 5000 RPM, the acceleration is 1000 RPM / s, and the spin coating time is 30s. The gel spin coating operation in step (2) is repeated, and the thick gel is spin-coated on the first-stage substrate 5-6 times. After each spin coating, the film is placed on a magnetic rotary heating table and dried at 120°C for 3 minutes, then placed in a muffle furnace and heated to 400°C for 2 minutes. At this time, a thick sol-filled viscous bonding layer is formed. The thickness of the thick sol-filled viscous bonding layer is 240μm. A secondary sintering operation is then performed to form a composite thick film structure and further promote the formation of the crystal phase. It is placed in a muffle furnace and sintered for a second time at 800°C for 1 hour to obtain the preliminary finished product of the second stage, which is recorded as the second-stage substrate.

[0066] (4) Annealing treatment

[0067] The second-stage substrate obtained in step (3) was annealed at 1000°C in air for 5 hours to obtain a BaTi2O5 ferroelectric thick film with a thickness of 152 μm. The thickness of the resulting BaTi2O5 ferroelectric thick film was less than that of the thick sol-filled viscous bonding layer, possibly due to the loss of the ferroelectric film caused by the annealing treatment after the thick sol filling.

[0068] The BaTi2O5 ferroelectric thick film prepared above was characterized, and the results are as follows:

[0069] Figure 4 This is the XRD diffraction pattern of BaTi2O5 ferroelectric thick film. It can be seen from the figure that the diffraction peak is obvious and basically coincides with the BaTi2O5 peak.

[0070] Figure 5 3 is a scanning electron microscope image of the BaTi2O5 ferroelectric thick film. It can be seen from the figure that the surface of the BaTi2O5 ferroelectric thick film prepared in Example 1 is relatively dense.

[0071] Figure 6 This is a scanning electron microscope image of the edge of the BaTi2O5 ferroelectric thick film. It can be seen from the figure that the edge of the BaTi2O5 ferroelectric thick film prepared in Example 1 is relatively thick, about 152μm.

[0072] Figure 7 This is the piezoelectric force microscope hysteresis loop spectrum of the BaTi2O5 ferroelectric thick film. It can be seen from the figure that the BaTi2O5 ferroelectric thick film prepared by Example 1 can obtain a hysteresis loop, indicating that the BaTi2O5 ferroelectric thick film prepared by the present invention has more significant ferroelectric properties.

[0073] Example 2:

[0074] A barium titanium-based ferroelectric thick film——BaTiO3 ferroelectric thick film

[0075] The preparation method thereof is different from that of Example 1 except that: in step (1), when preparing the composite precursor dilute gel and the composite precursor concentrated gel, Ba(CH3COO)2 (99.99%), C 16 H 36 O4Ti (≥97.00%) and CH3COOH (>99.50%) raw materials, weigh 5.11g of Ba(CH3COO)2, and change the amount of other substances added in proportion. The rest of the steps are the same as in Example 1.

[0076] The BaTi2O5 ferroelectric thick film prepared above was characterized, and the results are as follows:

[0077] Figure 8 This is the XRD diffraction pattern of BaTiO3 ferroelectric thick film. It can be seen from the figure that the diffraction peak is obvious and basically coincides with the BaTiO3 peak.

[0078] Figure 9 3 is a scanning electron microscope image of the BaTiO3 ferroelectric thick film. It can be seen from the figure that the edge of the BaTiO3 ferroelectric thick film prepared in Example 2 is relatively thick, about 120μm.

[0079] Figure 10 This is the piezoelectric force microscope hysteresis loop spectrum of the BaTiO3 ferroelectric thick film prepared in Example 2. It can be seen from the figure that the BaTiO3 ferroelectric thick film prepared in Example 2 can obtain a hysteresis loop, indicating that the BaTiO3 ferroelectric thick film prepared by the present invention has more significant ferroelectric properties.

[0080] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A method for preparing a barium-titanium-based ferroelectric thick film, characterized in that: The method comprises the following steps: 1) preparing a dilute barium precursor solution and a concentrated barium precursor solution containing a barium source and a hydrolysis inhibitor, and a dilute titanium precursor solution and a concentrated titanium precursor solution containing a titanium source and a hydrolysis inhibitor, mixing and stirring the dilute barium precursor solution and the dilute titanium precursor solution, adding an anti-cracking agent and aging to obtain a composite precursor dilute gel, and mixing and stirring the concentrated barium precursor solution and the concentrated titanium precursor solution, adding an anti-cracking solvent and aging to obtain a composite precursor concentrated gel; 2) Spin coating the composite precursor dilute gel on the substrate multiple times, drying and heating after each spin coating to obtain a dilute sol three-dimensional network adhesion layer, and sintering it once to obtain a first-stage substrate; 3) Spin coating the concentrated gel on the first-stage substrate in step 2) multiple times, drying and heating after each spin coating to obtain a concentrated gel-filled viscous bonding layer, and sintering the layer twice to obtain a second-stage substrate; 4) Annealing the second-stage substrate in step 3) to obtain a barium-titanium-based ferroelectric thick film; the thickness of the barium-titanium-based ferroelectric thick film is 150-250 μm.

2. The method for preparing a barium-titanium-based ferroelectric thick film according to claim 1, wherein: In step 1), the feed ratio of the barium source, solvent and hydrolysis inhibitor in the dilute barium precursor solution is (5-6) g: (20-30) mL: (6-8) mL, and the feed ratio of the barium source, solvent and hydrolysis inhibitor in the concentrated barium precursor solution is (5-6) g: (18-24) mL: (6-8) mL; In the titanium precursor dilute solution, the feed ratio of the titanium source, the solvent, and the hydrolysis inhibitor is (5-7) mL: (25-35) mL: (6-8) mL. In the titanium precursor concentrated solution, the feed ratio of the titanium source, the solvent, and the hydrolysis inhibitor is (5-7) mL: (20-28) mL: (6-8) mL. The volume ratio of the dilute barium precursor solution or the concentrated barium precursor solution to the anti-cracking agent is 1:(0.17-0.2); In the composite precursor dilute gel and the composite precursor concentrated gel, the molar ratio of the barium element to the titanium element is 1:(1-2).

3. The method for preparing the barium-titanium-based ferroelectric thick film according to claim 2, characterized in that: The preparation method of the dilute barium precursor solution or the concentrated barium precursor solution is as follows: a barium source and a solvent are mixed, stirred once and twice, and then a hydrolysis inhibitor is added to obtain the dilute barium precursor solution or the concentrated barium precursor solution; During the first stirring, the stirring temperature is 55-65°C, and during the second stirring, the stirring temperature is 75-85°C.

4. The method for preparing a barium-titanium-based ferroelectric thick film according to claim 2, wherein: The barium source is Ba(CH3COO)2, and the titanium source is C 16 H 36 O4Ti, and the solvent is CH3COOH.

5. The method for preparing the barium-titanium-based ferroelectric thick film according to claim 1, wherein: In step 1), the hydrolysis inhibitor is selected from any one of ethylene glycol monoethyl ether, ethylenediaminetetraacetic acid or citric acid; the anti-cracking agent is selected from any one of acetylacetone, ethylene carbonate or polyol; during the stirring, the stirring temperature is 75-85°C; during the aging, the aging temperature is 26-30°C, and the aging time is 24-36 hours.

6. The method for preparing a barium-titanium-based ferroelectric thick film according to claim 1, wherein: In step 2), the substrate is a platinum substrate or an aluminum substrate; in the spin coating of the composite precursor dilute gel, the spin coating number is 5-6 times, the spin coating speed is 4000-5000 RPM, and the spin coating time is 30 s; in the drying treatment, the drying temperature is 110-130°C, the drying time is 2-4 minutes, and the drying atmosphere is air or oxygen; in the heating treatment, the heating temperature is 380-410°C, the heating time is 1-2 minutes, and the heating atmosphere is air or oxygen; in the primary sintering, the sintering temperature is 790-810°C, the sintering time is 55-70 minutes, and the sintering atmosphere is air or oxygen.

7. The method for preparing a barium-titanium-based ferroelectric thick film according to claim 1, wherein: In step 3), in the spin coating of the concentrated gel, the number of spin coatings is 5-6 times, the spin coating speed is 4000-5000 RPM, and the spin coating time is 30 s; in the drying treatment, the drying temperature is 110-130°C, the drying time is 2-4 min, and the drying atmosphere is air or oxygen; in the heating treatment, the heating temperature is 380-410°C, the heating time is 1-2 min, and the heating atmosphere is air or oxygen; in the secondary sintering, the sintering temperature is 790-810°C, the sintering time is 55-70 min, and the sintering atmosphere is air or oxygen.

8. The method for preparing a barium-titanium-based ferroelectric thick film according to claim 1, wherein: In step 4), in the annealing treatment, the annealing temperature is 950-1100° C., the annealing time is 290-310 min, and the annealing atmosphere is air or oxygen.

9. The method for preparing a barium-titanium-based ferroelectric thick film according to claim 1, wherein: In step 2), the thickness of the dilute sol three-dimensional network adhesion layer is 100-200 μm; in step 3), the thickness of the concentrated gel-filled viscous adhesion layer is 200-300 μm.

10. A barium-titanium-based ferroelectric thick film, characterized in that: It is prepared by the method according to any one of claims 1 to 9.

Images