Lead zirconate titanate template and preparation method thereof

Abstract

The preparation method comprises the following steps: taking a lead source solution, an acidic zirconium source solution and a tetrabutyl titanate ethanol solution, dropwise adding the tetrabutyl titanate ethanol solution into the zirconium source solution under a stirring condition, and continuously and uniformly stirring to obtain a zirconium-titanium mixed solution; the zirconium source solution is acidic; dropwise adding the lead source solution into the zirconium-titanium mixed solution, adding a complexing agent, and stirring to obtain a uniform precursor solution; adding a mineralizer into the precursor solution, stirring until the mineralizer is completely dissolved, and then adjusting the pH value of a hydrothermal reaction system to be alkaline to obtain a hydrothermal reaction solution; putting the hydrothermal reaction liquid into a high-pressure reaction kettle for hydrothermal reaction, and naturally cooling to room temperature after the hydrothermal reaction is completed; washing and drying the obtained product to obtain a lead zirconate titanate template initial product; roasting and cooling the lead zirconate titanate template primary product to obtain a lead zirconate titanate template; the lead zirconate titanate template method is low in temperature and controllable in morphology, and the product is suitable for textured ceramic and ferroelectric epitaxial growth.

Description

Technical Field

[0001] This invention belongs to the field of functional material preparation technology, specifically relating to a lead zirconate titanate template and its preparation method. Background Technology

[0002] PZT-based ceramics are the mainstream core material in the field of commercial piezoelectric ceramics due to their excellent piezoelectric properties, high phase transition temperature, and tunable composition. For half a century, the formulation and piezoelectric properties of PZT-based commercial ceramics have remained similar to those of the 1970s, without any significant breakthroughs.

[0003] In recent years, the successful preparation of textured piezoelectric ceramics has significantly improved the piezoelectric properties of ceramics. However, the commonly used barium titanate and strontium titanate templates undergo severe chemical reactions with the PZT matrix, preventing the texturing of PZT-based ceramics. Even though some articles have reported texturing of PZT ceramics, their specific preparation methods cannot meet the requirements for engineering, mass production, and application. The successful preparation of PZT templates can overcome the chemical reaction between the template and the PZT matrix, enabling the successful texturing of commercially available PZT-based ceramics. This significantly improves the piezoelectric properties of PZT ceramics, meeting the urgent demand for high-performance piezoelectric materials in fields such as piezoelectric sensors, ferroelectric memories, and ultrasonic transducers. Currently, the main method for preparing PZT templates is the molten salt method. However, the PZT templates prepared by this method have a low Zr content (<10%) and insufficient chemical stability, making it impossible to texture commercially available PZT ceramic components.

[0004] In addition, patent CN108622931A discloses a method for preparing micron-sized sheet-like lead zirconate titanate crystals, which uses a molten salt method to prepare sheet-like crystals. <001> Preferred-oriented lead bismuth titanate crystals were used as precursors. These precursor crystals were mixed with PbO and ZrO2 at a predetermined molar ratio via a topological chemical reaction. The resulting powder was then mixed with NaCl at a predetermined mass ratio. The mixture was held at 850℃~1050℃, and finally, NaCl and Bi2O3 were removed from the calcined product by washing with hot deionized water and acid leaching, yielding micron-sized flake-shaped lead zirconate titanate (Pb(ZrO2)) sheets. 0.5 Ti 0.5 The O3 crystal has a thin, sheet-like microstructure with a large aspect ratio and high orientation. It is used as a seed crystal for highly oriented lead zirconate titanate textured ceramics. The precursor is prepared by molten salt method and topological transformation, both of which use chloride salts (KCl and / or NaCl) as fluxes. This method has high energy consumption and more stringent reaction conditions.

[0005] Therefore, developing a PZT template preparation method with mild reaction conditions, uniform product morphology, high orientation, high preparation efficiency, and controllable stoichiometry has become an urgent technical problem to be solved in this field. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a method for preparing lead zirconate titanate (Pb(Zr,Ti)O3, abbreviated as PZT) templates based on a hydrothermal method. This method is suitable for preparing PZT templates with high orientation and high crystallinity. The method has low temperature and controllable morphology, and the product is suitable for the growth of textured ceramics and ferroelectric epitaxy. This PZT template can be widely used in the preparation of core electronic materials such as piezoelectric sensors, ferroelectric memories, and ultrasonic transducers.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a method for preparing a lead zirconate titanate template, comprising the following steps: A lead source solution, a zirconium source solution, and a tetrabutyl titanate ethanol solution were prepared according to a Zr / Ti molar ratio of 0.45-0.65:0.55-0.35 and a Pb / (Zr+Ti) molar ratio of 1.05-1.2:1. The tetrabutyl titanate ethanol solution was added dropwise to the zirconium source solution while stirring continuously until a transparent and clear state was obtained, resulting in a zirconium-titanium mixed solution. The zirconium source solution was acidic. The lead source solution was added dropwise to the zirconium-titanium mixed solution, and a complexing agent was added and stirred until it became yellow and transparent, thus obtaining a homogeneous precursor solution. Add a mineralizing agent to the precursor solution and stir until the mineralizing agent is completely dissolved. Then adjust the pH of the hydrothermal reaction system to alkaline to obtain the hydrothermal reaction solution. The hydrothermal reaction solution is placed in a high-pressure reactor for hydrothermal reaction. The reactor is filled to 60%-80% at 180-220℃ and kept at that temperature for 8-16 hours. The reactor is continuously stirred during the hydrothermal reaction. After the hydrothermal reaction is completed, the reactor is naturally cooled to room temperature. The hydrothermal reaction product was washed and dried to obtain the lead zirconate titanate template primary product; The lead zirconate titanate template primary product was calcined at 400-600℃ for 2-4 hours, and then cooled to obtain high-purity lead zirconate titanate template.

[0008] Furthermore, lead nitrate, zirconium oxychloride, and tetrabutyl titanate were taken in proportion, and lead source solution, zirconium source solution, and tetrabutyl titanate ethanol solution were prepared using lead nitrate, zirconium oxychloride, and tetrabutyl titanate, respectively.

[0009] Furthermore, the zirconium source solution is obtained by dissolving zirconium oxychloride in deionized water, adding 1 mol / L hydrochloric acid solution to adjust the pH value to 1-2, and stirring until homogeneous.

[0010] Furthermore, the complexing agent is citric acid or disodium EDTA.

[0011] Furthermore, the tetrabutyl titanate ethanol solution is added at a rate of 50-100 mL / min, and the stirring speed during the addition process is 300-500 r / min.

[0012] Furthermore, the lead source solution was added at a dropping rate of 10-20 mL / min, and the molar ratio of the complexing agent to the metal ions was 1-1.5:1, including Pb. 2+ Zr 4+ and Ti 4+ .

[0013] Furthermore, the mineralizing agent is a mixture of potassium hydroxide and potassium fluoride in a volume ratio of 1:0.5-5, wherein the concentration of KOH is 2 mol / L-4 mol / L and the concentration of KF is 0.5 mol / L-1.5 mol / L. Furthermore, the pH value of the hydrothermal reaction system is adjusted to 12-14, and the stirring speed of the reactor during the hydrothermal reaction is 50-100 r / min.

[0014] Furthermore, the hydrothermal reaction product is washed and dried by repeatedly washing with deionized water until the pH of the washing solution is 7-8, then washing with anhydrous ethanol and drying.

[0015] A lead zirconate titanate template, obtained by the above-described preparation method, is in sheet form with a thickness of 0.1-0.9 μm and a length of 2-11 μm. 33 Not less than 730pC / N.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: By employing the synergistic effect of mixed mineralizers and complexing agents and optimizing reaction process parameters, the reaction time is shortened to 8-16 hours, significantly improving production efficiency compared to the traditional hydrothermal method. Furthermore, the reaction temperature is below 220℃, resulting in a significant reduction in energy consumption.

[0017] Plate-like PZT template seed crystals were prepared by crystal face growth regulation and phase structure induction: Different crystal faces of PZT crystals have different surface energies. Mineralizing agents (such as NaOH and KOH) in the hydrothermal environment selectively adsorb on high surface energy crystal faces, inhibiting their growth and promoting the expansion of low surface energy crystal faces along the two-dimensional direction. At the same time, high temperature and high pressure drive the crystal phase to transform from amorphous or metastable to perovskite phase PZT. Meanwhile, the plate-like morphology is fixed during the phase transformation process, and finally a plate-like template with uniform size and regular morphology is formed.

[0018] After low-temperature calcination, the surface activity of the product is enhanced, resulting in excellent subsequent bonding performance with the matrix material. The piezoelectric constant d of the prepared textured PZT ceramic is also improved. 33 It can reach over 1000 pC / N, improving the performance of ceramics by 30%-50% compared to those prepared by traditional methods.

[0019] The PZT template prepared by this invention has a uniform sheet-like morphology with sheet dimensions of 100-800 nm thickness, 2-12 μm diameter, and 5-10 μm length, and the stoichiometry is precisely controllable. The method of this invention is simple to operate, has mild reaction conditions, and good repeatability, making it suitable for large-scale industrial production and with broad application prospects. Attached Figure Description

[0020] Figure 1 The XRD pattern of the PZT template in Case 1 is shown.

[0021] Figure 2 SEM photos of the PZT template in Case 1.

[0022] Figure 3 Dielectric temperature spectrum of PZT textured ceramic in Case 3. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0025] Example 1 The preparation of lead zirconate titanate templates based on the hydrothermal method includes the following steps: Precursor solution preparation: Weigh lead nitrate, zirconium oxychloride, and tetrabutyl titanate according to a Zr / Ti molar ratio of 0.52:0.48 and a Pb / (Zr+Ti) molar ratio of 1.1:1. Dissolve lead nitrate in deionized water to obtain a lead source solution. Dissolve zirconium oxychloride in deionized water, adjust the pH to 1.5 with 1 mol / L hydrochloric acid, and stir for 30 minutes to obtain a zirconium source solution. Dissolve tetrabutyl titanate in anhydrous ethanol and slowly add it dropwise to the zirconium source solution at 50 mL / min, and stir for 60 minutes to obtain a transparent and clear zirconium-titanium mixed solution. Add the lead source solution dropwise to the zirconium-titanium mixed solution at 20 mL / min, add citric acid (complexing agent to metal ion molar ratio of 1.2:1), and stir for 90 minutes to obtain a yellow and transparent precursor solution.

[0026] Preparation of hydrothermal reaction system: Add KOH and KF (volume ratio of 1:0.5) to the precursor solution to make the KOH concentration 3mol / L and the KF concentration 1mol / L. After stirring and dissolving, adjust the pH to 13 and transfer to a high-pressure reactor with a filling degree of 70%.

[0027] Hydrothermal reaction: The high-pressure reactor is heated to 200℃ and held for 12 hours with a stirring speed of 80 r / min. After the reaction is completed, it is naturally cooled to room temperature with a heating rate of 8℃ / min. Product post-treatment: The hydrothermal reaction product was washed with deionized water to pH 7.5, and then washed three times with anhydrous ethanol; vacuum dried at 60℃ for 10 hours; and calcined at 500℃ for 3 hours to obtain flake-like Pb(Zr) 0.52 Ti 0.48 O3 template, with a thickness of 0.2~0.5μm, a length of 2~7μm, and an aspect ratio greater than 10.

[0028] Pb(Zr)-containing materials were prepared using template grain growth technology. 0.52 Ti 0.48 O3 textured piezoelectric ceramics, with a piezoelectric constant d 33 =1040pC / N, Curie temperature is 360℃.

[0029] Example 2 The preparation of lead zirconate titanate templates based on the hydrothermal method includes the following steps: Precursor solution preparation: Weigh the raw materials according to the Zr / Ti molar ratio of 0.6:0.4 and the Pb / (Zr+Ti) molar ratio of 1.15:1; the lead source solution and zirconium source solution are prepared in the same way as in Example 1; dissolve tetrabutyl titanate in anhydrous ethanol and add it dropwise to the zirconium source solution, stir for 60 minutes to obtain a transparent and clear solution; add the lead source solution dropwise to the zirconium-titanium mixed solution at a rate of 10 mL / min, add disodium ethylenediaminetetraacetate (complexing agent to metal ion molar ratio of 1.4:1), stir for 90 minutes to obtain a yellow transparent precursor solution.

[0030] Hydrothermal reaction system configuration: Add KOH (concentration 4 mol / L) and KF (concentration 1.2 mol / L) in a volume ratio of 1:5, adjust pH to 13.5, and fill the reactor to 75%.

[0031] Hydrothermal reaction: Heat to 210℃ (heating rate 10℃ / min), hold for 10 hours, stir at 100r / min, and cool naturally.

[0032] Product post-treatment: Wash with deionized water until pH=7, wash twice with anhydrous ethanol; vacuum dry at 70℃ for 8 hours; calcine at 550℃ for 2.5 hours to obtain sheet-like PZT templates with a thickness of 0.1~0.6μm, a length of 2~8μm, and an aspect ratio greater than 15.

[0033] Pb(Zr)-containing materials were prepared using template grain growth technology. 0.55 Ti 0.45 O3 textured piezoelectric ceramics, with a piezoelectric constant d 33 =730pC / N, Curie temperature is 395℃.

[0034] Example 3 The preparation of lead zirconate titanate templates based on the hydrothermal method includes the following steps: Precursor solution preparation: Weigh the raw materials according to the Zr / Ti molar ratio of 0.5:0.5 and the Pb / (Zr+Ti) molar ratio of 1.2:1; the lead source solution and zirconium source solution are prepared in the same way as in Example 1; dissolve tetrabutyl titanate in anhydrous ethanol and add it dropwise to the zirconium source solution, and stir for 60 minutes; add disodium ethylenediaminetetraacetate (complexing agent to metal ion molar ratio of 1.4:1), and stir for 90 minutes to obtain the precursor solution.

[0035] Hydrothermal reaction system configuration: Add KOH (concentration 2 mol / L) and KF (concentration 1.5 mol / L), with a KOH to KF solution volume ratio of 1:1, adjust pH to 13.8, and fill the reactor to 80% capacity.

[0036] Hydrothermal reaction: Heat to 210℃ (heating rate 10℃ / min), hold for 10 hours, stir at 100r / min, and cool naturally.

[0037] Product post-treatment: Wash with deionized water until pH=7, wash twice with anhydrous ethanol; vacuum dry at 70℃ for 8 hours; calcine at 550℃ for 2.5 hours to obtain sheet-like PZT templates (thickness 0.4~0.9μm, length 2~11μm), with an aspect ratio greater than 10.

[0038] Pb(Zr)-containing materials were prepared using template grain growth technology. 0.54 Ti 0.46 O3 textured piezoelectric ceramics, with a piezoelectric constant d 33 =920pC / N, Curie temperature is 377℃.

[0039] Example 4 The preparation of lead zirconate titanate templates based on the hydrothermal method includes the following steps: Precursor solution preparation: Lead nitrate, zirconium oxychloride, and tetrabutyl titanate were weighed according to a Zr / Ti molar ratio of 0.45:0.55 and a Pb / (Zr+Ti) molar ratio of 1.1:1. Lead nitrate was dissolved in deionized water to obtain a lead source solution. Zirconium oxychloride was dissolved in deionized water, and the pH was adjusted to 1.5 with 1 mol / L hydrochloric acid. The solution was stirred for 30 minutes to obtain a zirconium source solution. Tetrabutyl titanate was dissolved in anhydrous ethanol and slowly added dropwise to the zirconium source solution at 100 mL / min. The solution was stirred for 60 minutes to obtain a clear zirconium-titanium mixed solution. The lead source solution was added dropwise to the zirconium-titanium mixed solution at 10 mL / min. Citric acid was added (complexing agent to metal ion molar ratio of 1.2:1), and the solution was stirred for 90 minutes to obtain a yellow and clear precursor solution.

[0040] Preparation of hydrothermal reaction system: Add KOH and KF (volume ratio of 1:4) to the precursor solution to make the KOH concentration 4mol / L and the KF concentration 1.5mol / L. After stirring and dissolving, adjust the pH to 13 and transfer to a high-pressure reactor with a filling degree of 70%.

[0041] Hydrothermal reaction: The high-pressure reactor is heated to 200℃ and held for 12 hours with a stirring speed of 70 r / min. After the reaction is completed, it is naturally cooled to room temperature with a heating rate of 8℃ / min. Product post-treatment: The hydrothermal reaction product was washed with deionized water to pH 7.5, and then washed three times with anhydrous ethanol; vacuum dried at 60℃ for 10 hours; and calcined at 500℃ for 3 hours to obtain flake-like Pb(Zr) 0.45 Ti 0.55 O3 template, with a thickness of 0.1~0.4μm, a length of 4~8μm, and an aspect ratio greater than 20.

[0042] Pb(Zr)-containing materials were prepared using template grain growth technology. 0.55 Ti 0.45 O3 textured piezoelectric ceramics, with a piezoelectric constant d 33 =810pC / N, Curie temperature is 340℃.

[0043] Example 5 The preparation of lead zirconate titanate templates based on the hydrothermal method includes the following steps: Precursor solution preparation: Lead nitrate, zirconium oxychloride, and tetrabutyl titanate were weighed according to a Zr / Ti molar ratio of 0.48:0.52 and a Pb / (Zr+Ti) molar ratio of 1.1:1. Lead nitrate was dissolved in deionized water to obtain a lead source solution. Zirconium oxychloride was dissolved in deionized water, and the pH was adjusted to 1.5 with 1 mol / L hydrochloric acid. The solution was stirred for 30 minutes to obtain a zirconium source solution. Tetrabutyl titanate was dissolved in anhydrous ethanol and slowly added dropwise at 80 mL / min to the zirconium source solution. The solution was stirred for 60 minutes to obtain a clear zirconium-titanium mixed solution. The lead source solution was added dropwise at 15 mL / min to the zirconium-titanium mixed solution. Citric acid was added (complexing agent to metal ion molar ratio of 1:1), and the solution was stirred for 90 minutes to obtain a yellow and clear precursor solution.

[0044] Preparation of hydrothermal reaction system: Add KOH and KF (volume ratio of 1:3) to the precursor solution to make the KOH concentration 3.3mol / L and the KF concentration 1.2mol / L. After stirring and dissolving, adjust the pH to 13 and transfer to a high-pressure reactor with a filling degree of 70%.

[0045] Hydrothermal reaction: The high-pressure reactor is heated to 200℃ and held for 12 hours with a stirring speed of 50 r / min. After the reaction is completed, it is naturally cooled to room temperature with a heating rate of 8℃ / min. Product post-treatment: The hydrothermal reaction product was washed with deionized water to pH 7.5, and then washed three times with anhydrous ethanol; vacuum dried at 60℃ for 10 hours; and calcined at 500℃ for 3 hours to obtain flake-like Pb(Zr) 0.45 Ti 0.55 O3 template, with a thickness of 0.4~0.7μm, a length of 3~7μm, and an aspect ratio greater than 8.

[0046] Pb(Zr)-containing materials were prepared using template grain growth technology. 0.52 Ti 0.48 O3 textured piezoelectric ceramics, with a piezoelectric constant d 33 =1010pC / N, Curie temperature is 358℃.

[0047] Example 6 The preparation of lead zirconate titanate templates based on the hydrothermal method includes the following steps: Precursor solution preparation: Weigh lead nitrate, zirconium oxychloride, and tetrabutyl titanate according to a Zr / Ti molar ratio of 0.48:0.52 and a Pb / (Zr+Ti) molar ratio of 1.1:1. Dissolve lead nitrate in deionized water to obtain a lead source solution. Dissolve zirconium oxychloride in deionized water, adjust the pH to 1.5 with 1 mol / L hydrochloric acid, and stir for 30 minutes to obtain a zirconium source solution. Dissolve tetrabutyl titanate in anhydrous ethanol and slowly add it dropwise to the zirconium source solution at 60 mL / min, and stir for 60 minutes to obtain a transparent and clear zirconium-titanium mixed solution. Add the lead source solution dropwise to the zirconium-titanium mixed solution at 12 mL / min, add citric acid (complexing agent to metal ion molar ratio of 1:1.2), and stir for 90 minutes until a yellow and transparent precursor solution is obtained.

[0048] Preparation of hydrothermal reaction system: Add KOH and KF (volume ratio 1:1) to the precursor solution to make the KOH concentration 3mol / L and the KF concentration 1mol / L. After stirring and dissolving, adjust the pH to 13 and transfer to a high-pressure reactor with a filling degree of 60%.

[0049] Hydrothermal reaction: The high-pressure reactor is heated to 180℃ and held for 15 hours with a stirring speed of 60 r / min. After the reaction is completed, it is naturally cooled to room temperature with a heating rate of 9℃ / min. Product post-treatment: The hydrothermal reaction product was washed with deionized water to pH 7.5, and then washed four times with anhydrous ethanol; vacuum dried at 60℃ for 10 hours; and calcined at 500℃ for 3 hours to obtain flake-like Pb(Zr) 0.48 Ti 0.52 O3 template, with a thickness of 0.1~0.3μm, a length of 2~4μm, and an aspect ratio greater than 10.

[0050] Pb(Zr)-containing materials were prepared using template grain growth technology. 0.54 Ti 0.46 O3 textured piezoelectric ceramics, with a piezoelectric constant d 33 =920pC / N, Curie temperature is 348℃.

[0051] Example 7 The preparation of lead zirconate titanate templates based on the hydrothermal method includes the following steps: Precursor solution preparation: Weigh lead nitrate, zirconium oxychloride, and tetrabutyl titanate according to a Zr / Ti molar ratio of 0.60:0.40 and a Pb / (Zr+Ti) molar ratio of 1.1:1. Dissolve lead nitrate in deionized water to obtain a lead source solution. Dissolve zirconium oxychloride in deionized water, adjust the pH to 1.5 with 1 mol / L hydrochloric acid, and stir for 30 minutes to obtain a zirconium source solution. Dissolve tetrabutyl titanate in anhydrous ethanol and slowly add it dropwise to the zirconium source solution at 80 mL / min, and stir for 60 minutes to obtain a transparent and clear zirconium-titanium mixed solution. Add the lead source solution dropwise to the zirconium-titanium mixed solution at 10 mL / min, add citric acid (complexing agent to metal ion molar ratio 1:1), and stir for 90 minutes to obtain a yellow and transparent precursor solution.

[0052] Preparation of hydrothermal reaction system: Add KOH and KF (volume ratio of 1:1.8) to the precursor solution to make the KOH concentration 2.8mol / L and the KF concentration 1.3mol / L. After stirring and dissolving, adjust the pH to 13 and transfer to a high-pressure reactor with a filling degree of 60%.

[0053] Hydrothermal reaction: The high-pressure reactor is heated to 180℃ and held for 8 hours with a stirring speed of 65 r / min. After the reaction is completed, it is naturally cooled to room temperature with a heating rate of 9℃ / min. Product post-treatment: The hydrothermal reaction product was washed with deionized water to pH 7.5, and then washed three times with anhydrous ethanol; vacuum dried at 60℃ for 10 hours; and calcined at 400℃ for 4 hours to obtain flake-like Pb(Zr) 0.48 Ti 0.52 O3 template, with a thickness of 0.1~0.2μm, a length of 2~4μm, and an aspect ratio greater than 15.

[0054] Pb(Zr)-containing materials were prepared using template grain growth technology. 0.52 Ti 0.48 O3 textured piezoelectric ceramics, with a piezoelectric constant d 33 =980pC / N, Curie temperature is 362℃.

[0055] Example 8 The preparation of lead zirconate titanate templates based on the hydrothermal method includes the following steps: Precursor solution preparation: Lead nitrate, zirconium oxychloride, and tetrabutyl titanate were weighed according to a Zr / Ti molar ratio of 0.60:0.40 and a Pb / (Zr+Ti) molar ratio of 1.1:1. Lead nitrate was dissolved in deionized water to obtain a lead source solution. Zirconium oxychloride was dissolved in deionized water, and the pH was adjusted to 1.5 with 1 mol / L hydrochloric acid. The solution was stirred for 30 minutes to obtain a zirconium source solution. Tetrabutyl titanate was dissolved in anhydrous ethanol and slowly added dropwise to the zirconium source solution at 75 mL / min. The solution was stirred for 60 minutes to obtain a transparent and clear zirconium-titanium mixed solution. The lead source solution was added dropwise to the zirconium-titanium mixed solution at 12 mL / min. Citric acid was added (the molar ratio of complexing agent to metal ions was 1:1.3), and the solution was stirred for 90 minutes to obtain a yellow and transparent precursor solution.

[0056] Preparation of hydrothermal reaction system: Add KOH and KF (volume ratio of 1:3.4) to the precursor solution to make the KOH concentration 3mol / L and the KF concentration 1.5mol / L. After stirring and dissolving, adjust the pH to 13 and transfer to a high-pressure reactor with a filling degree of 80%.

[0057] Hydrothermal reaction: The high-pressure reactor is heated to 200℃ and held for 8 hours with a stirring speed of 75 r / min. After the reaction is completed, it is naturally cooled to room temperature with a heating rate of 9℃ / min. Product post-treatment: The hydrothermal reaction product was washed with deionized water to pH 7.5, and then washed 7 times with anhydrous ethanol; vacuum dried at 60℃ for 10 hours; and calcined at 500℃ for 3 hours to obtain flake-like Pb(Zr) 0.48 Ti 0.52 O3 template, with a thickness of 0.6~1μm, a length of 6~12μm, and an aspect ratio greater than 10.

[0058] Pb(Zr)-containing materials were prepared using template grain growth technology. 0.52 Ti 0.48 O3 textured piezoelectric ceramics, with a piezoelectric constant d 33 =1032pC / N, Curie temperature is 360℃.

[0059] Figure 1 To implement Pb(Zr) in Case 1 0.52 Ti 0.48 The XRD pattern of the O3 template powder shows that its peak position and peak intensity are consistent with the PDF card (#70-4059), exhibiting a pure perovskite phase structure. Figure 2 To implement Pb(Zr) in Case 1 0.52 Ti 0.48 SEM images of O3 template powder show that its microstructure is flake-like, with a radial length between 2 and 7 μm and a thickness between 0.2 and 0.5 μm. The length-to-thickness ratio is greater than 10. Figure 3 In Implementation Case 3, Pb(Zr)0.50 Ti 0.50 The O3 template seed crystal preparation composition is Pb(Zr) 0.54 Ti 0.46 The dielectric temperature spectrum of O3 textured ceramics shows a dielectric constant peak, which corresponds to the Curie temperature of 377°C. o C.

[0060] In summary, the method for preparing lead zirconate titanate templates provided by this invention is based on a hydrothermal method. A lead source solution, a zirconate source solution, and a tetrabutyl titanate ethanol solution are taken. The tetrabutyl titanate ethanol solution is added dropwise to the zirconate source solution while stirring continuously until homogeneous, resulting in a zirconate-titanium mixed solution. The zirconate source solution is acidic. The lead source solution is then added dropwise to the zirconate-titanium mixed solution, and a complexing agent is added and stirred simultaneously to obtain a homogeneous precursor solution. A mineralizing agent is added to the precursor solution and stirred until the mineralizing agent is completely dissolved. The pH of the hydrothermal reaction system was adjusted to alkaline to obtain a hydrothermal reaction solution. The hydrothermal reaction solution was placed in a high-pressure reactor for hydrothermal reaction at a temperature of 180-220℃ for 8-16 hours. The reactor was continuously stirred during the hydrothermal reaction. After the hydrothermal reaction was completed, the mixture was allowed to cool naturally to room temperature. The hydrothermal reaction product was washed and dried to obtain a lead zirconate titanate template. The lead zirconate titanate template was calcined at 400-600℃ for 2-4 hours and then cooled to obtain a high-purity lead zirconate titanate template.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a lead zirconate titanate template, characterized in that, Includes the following steps: A lead source solution, a zirconium source solution, and a tetrabutyl titanate ethanol solution were prepared according to a Zr / Ti molar ratio of 0.45-0.65:0.55-0.35 and a Pb / (Zr+Ti) molar ratio of 1.05-1.2:

1. The tetrabutyl titanate ethanol solution was added dropwise to the zirconium source solution while stirring continuously until a transparent and clear state was obtained, resulting in a zirconium-titanium mixed solution. The zirconium source solution was acidic. The lead source solution was added dropwise to the zirconium-titanium mixed solution, and a complexing agent was added and stirred until it became yellow and transparent, thus obtaining a homogeneous precursor solution. Add a mineralizing agent to the precursor solution and stir until the mineralizing agent is completely dissolved. Then adjust the pH of the hydrothermal reaction system to alkaline to obtain the hydrothermal reaction solution. The hydrothermal reaction solution is placed in a high-pressure reactor for hydrothermal reaction. The reactor is filled to 60%-80% and kept at 180-220℃ for 8-16 hours. The reactor is continuously stirred during the hydrothermal reaction. After the hydrothermal reaction is completed, it is naturally cooled to room temperature. The hydrothermal reaction product was washed and dried to obtain the lead zirconate titanate template primary product; The lead zirconate titanate template primary product was calcined at 400-600℃ for 2-4 hours, and then cooled to obtain high-purity lead zirconate titanate template.

2. The method for preparing the lead zirconate titanate template according to claim 1, characterized in that, Lead nitrate, zirconium oxychloride, and tetrabutyl titanate were taken in the specified proportions, and lead source solution, zirconium source solution, and tetrabutyl titanate ethanol solution were prepared using lead nitrate, zirconium oxychloride, and tetrabutyl titanate, respectively.

3. The method for preparing the lead zirconate titanate template according to claim 1, characterized in that, The zirconium source solution is obtained by dissolving zirconium oxychloride in deionized water, adding 1 mol / L hydrochloric acid solution to adjust the pH to 1-2, and stirring until homogeneous.

4. The method for preparing the lead zirconate titanate template according to claim 1, characterized in that, The complexing agent is citric acid or disodium EDTA.

5. The method for preparing the lead zirconate titanate template according to claim 1, characterized in that, The tetrabutyl titanate ethanol solution was added at a rate of 50-100 mL / min, and the stirring speed during the addition process was 300-500 r / min.

6. The method for preparing the lead zirconate titanate template according to claim 1, characterized in that, The lead source solution was added at a dropping rate of 10-20 mL / min, and the molar ratio of the complexing agent to the metal ions was 1-1.5:

1. The metal ions included Pb. 2+ Zr 4+ and Ti 4+ .

7. The method for preparing the lead zirconate titanate template according to claim 1, characterized in that, The mineralizing agent is a mixture of potassium hydroxide and potassium fluoride in a volume ratio of 1:0.5-5, wherein the concentration of KOH is 2mol / L-4mol / L and the concentration of KF is 0.5mol / L-1.5mol / L.

8. The method for preparing the lead zirconate titanate template according to claim 1, characterized in that, Adjust the pH of the hydrothermal reaction system to 12-14, and maintain the stirring speed of the reactor at 50-100 r / min during the hydrothermal reaction.

9. The method for preparing the lead zirconate titanate template according to claim 1, characterized in that, Washing and drying the hydrothermal reaction products involves repeatedly washing with deionized water until the pH of the washing solution is 7-8, then washing with anhydrous ethanol and drying.

10. A lead zirconate titanate template, characterized in that, The lead zirconate titanate template as described in any one of claims 1-9 is obtained in sheet form, with a thickness of 0.1-0.9 μm and a length of 2-11 μm. 33 Not less than 730pC / N.

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