Lead zirconate titanate porous piezoelectric ceramic as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of special ceramic preparation, and particularly relates to lead zirconate titanate porous piezoelectric ceramic as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing an alkenyl-containing organic monomer, a cross-linking agent, an alcohol organic solvent, lead zirconate titanate powder and a dispersing agent, grinding, removing bubbles from the obtained premix, mixing with an initiator and an amine catalyst, and carrying out a polymerization reaction to obtain a gel blank; and sequentially drying and sintering the gel blank to obtain the lead zirconate titanate porous piezoelectric ceramic. The porosity of the lead zirconate titanate porous piezoelectric ceramic ranges from 45.40% to 64.87%, the piezoelectric voltage coefficient ranges from 43.95 * 10 <-3 > to 81.71 * 10 <-3 > Vm / N, the energy collection quality factor ranges from 9.95 * 10 <-12 > to 20.28 * 10 <-12 > m < 2 > / N, and the lead zirconate titanate porous piezoelectric ceramic has good application in high-sensitivity output and excellent energy collection materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of special ceramic preparation, and in particular relates to a lead zirconate titanate porous piezoelectric ceramic and a preparation method and application thereof. Background Art

[0002] The rapid development of the Internet of Things (IoT) and wearable devices has led to a surge in demand for sensor networks, for which power supply is crucial. Traditional battery-powered systems have numerous drawbacks, such as the need for frequent battery replacement, which increases maintenance costs and workload. Furthermore, in some specialized environments where power wiring and battery replacement are difficult to access, traditional power supply methods are particularly difficult to meet demand. At the same time, the massive consumption of fossil fuels and the associated environmental pollution are driving the development of sustainable and clean energy sources, including thermal energy, wind energy, mechanical vibration energy, and solar energy. Mechanical vibration energy is ubiquitous in our living environment and can be harvested through the direct piezoelectric effect of piezoelectric energy harvesters. Therefore, piezoelectric energy harvesters are promising candidates for providing power to low-power sensor networks and wearable electronic devices.

[0003] Lead zirconate titanate (LZT) has a high piezoelectric charge constant and high Curie temperature and is often used as a piezoelectric ceramic matrix material. Researchers have conducted extensive research on optimizing piezoelectric energy harvesting performance, with material composition design, single crystal preparation, and texture engineering being the most common optimization methods. However, the intrinsic properties of piezoelectric materials dictate a strong positive correlation between the piezoelectric charge coefficient and the dielectric constant, making it extremely difficult to improve the energy output sensitivity and energy harvesting performance of piezoelectric materials. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a porous lead zirconate titanate piezoelectric ceramic and its preparation method and application. The porous lead zirconate titanate piezoelectric ceramic prepared by the present invention has high sensitive output and excellent energy harvesting performance.

[0005] The present invention provides a method for preparing a porous lead zirconate titanate piezoelectric ceramic, comprising the following steps:

[0006] An olefin-containing organic monomer, a cross-linking agent, an alcohol organic solvent, lead zirconate titanate powder and a dispersant are mixed and ground to obtain a premix;

[0007] After removing bubbles from the premix, the premix is ​​mixed with an initiator and an amine catalyst to carry out a polymerization reaction to obtain a gel body;

[0008] The gel blank is dried and sintered in sequence to obtain a lead zirconate titanate porous piezoelectric ceramic.

[0009] Preferably, the mass content of lead zirconate titanate powder in the premix is ​​15% to 50%.

[0010] Preferably, the alkenyl-containing organic monomer includes one or more of acrylamide, styrene and methyl methacrylate; the mass of the alkenyl-containing organic monomer is 16.5% to 17% of the mass of the alcohol organic solvent.

[0011] Preferably, the cross-linking agent includes one or more of methylenebisacrylamide, N,N-dimethylacrylamide and ethylene glycol dimethacrylate; the mass of the cross-linking agent is 5% to 6% of the mass of the alkenyl-containing organic monomer.

[0012] Preferably, the dispersant includes one or more of ammonium polyacrylate, ammonium citrate and ammonium tripolyphosphate; the mass of the dispersant is 0.3% to 1.5% of the total mass of the lead zirconate titanate powder, the olefinic organic monomer and the crosslinking agent.

[0013] Preferably, the amine catalyst includes tetramethylethylenediamine and / or triethanolamine; the mass of the amine catalyst is 2.5% to 3.5% of the mass of the alkenyl-containing organic monomer.

[0014] Preferably, the initiator comprises ammonium persulfate and / or benzoyl peroxide; the mass of the initiator is 14% to 16% of the mass of the alkenyl-containing organic monomer.

[0015] Preferably, the sintering temperature is 1250-1350° C., and the holding time is 3-5 hours.

[0016] The present invention also provides a lead zirconate titanate porous piezoelectric ceramic obtained by the preparation method described in the above technical solution, which has a porosity of 45% to 65%, a dielectric constant of 190 to 910, a piezoelectric charge coefficient of 120 to 360 pC / N, and a piezoelectric voltage coefficient of 40×10 -3 ~90×10 -3 Vm / N, energy harvesting quality factor is 9×10 -12 ~21×10 -12 m 2 / N.

[0017] The present invention also provides the use of the lead zirconate titanate porous piezoelectric ceramics described in the above technical solution in sensitive output and energy harvesting materials.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention provides a preparation method of a porous lead zirconate titanate piezoelectric ceramic, comprising the following steps: mixing an olefin-containing organic monomer, a cross-linking agent, an alcohol organic solvent, lead zirconate titanate powder, and a dispersant, and grinding the mixture to obtain a premix; removing bubbles from the premix, mixing the premix with an initiator and an amine catalyst, and performing a polymerization reaction to obtain a gel body; and sequentially drying and sintering the gel body to obtain a porous lead zirconate titanate piezoelectric ceramic.

[0020] The present invention adopts gel casting to introduce pores into piezoelectric ceramics, and introduces air with a low relative dielectric constant (dielectric constant close to 1) as a second phase into the piezoelectric ceramics to prepare porous piezoelectric ceramics, thereby reducing the dielectric constant. The present invention adopts gel casting to obtain ordered multi-level porous piezoelectric ceramics with a three-dimensional interconnected structure. On the basis of reducing the dielectric constant, the three-dimensional interconnected structure of the 3-3 type porous piezoelectric ceramics can enhance the charge transfer efficiency, improve the piezoelectric polarization efficiency and alleviate the piezoelectric charge coefficient (d 33 ) deterioration, achieving the decoupling of piezoelectric charge coefficient and dielectric constant, and greatly improving the sensitive output and energy harvesting performance.

[0021] The present invention utilizes a three-dimensional interconnected porous structure to achieve the decoupling of the piezoelectric charge coefficient and dielectric constant. The prepared lead zirconate titanate porous piezoelectric ceramic has high sensitivity output and excellent energy harvesting performance. The data in the examples show that the lead zirconate titanate porous piezoelectric ceramic prepared by the present invention has a porosity of 45.40% to 64.87%, a dielectric constant of 190.83 to 902.35, a piezoelectric charge coefficient of 129.42 to 351 pC / N, and a piezoelectric voltage coefficient of 43.95×10 -3 ~81.71×10 -3 Vm / N, the energy harvesting quality factor is 9.95×10 -12 ~20.28×10 -12 m 2 / N. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a performance comparison chart of the lead zirconate titanate porous piezoelectric ceramics prepared in Examples 1 to 4;

[0024] Figure 2 This is the SEM image of the porous piezoelectric ceramic of lead zirconate titanate prepared in Example 2. DETAILED DESCRIPTION

[0025] The present invention provides a method for preparing a porous lead zirconate titanate piezoelectric ceramic, comprising the following steps:

[0026] An olefin-containing organic monomer, a cross-linking agent, an alcohol organic solvent, lead zirconate titanate powder and a dispersant are mixed and ground to obtain a premix;

[0027] After removing bubbles from the premix, the premix is ​​mixed with an initiator and an amine catalyst to carry out a polymerization reaction to obtain a gel body;

[0028] The gel blank is dried and sintered in sequence to obtain a lead zirconate titanate porous piezoelectric ceramic.

[0029] In the present invention, unless otherwise specified, the materials and equipment used are commercially available products in the art.

[0030] The invention mixes and grinds an olefin-containing organic monomer, a cross-linking agent, an alcohol organic solvent, lead zirconate titanate powder and a dispersant to obtain a premix.

[0031] In the present invention, the alkenyl-containing organic monomer preferably includes one or more of acrylamide, styrene and methyl methacrylate; the mass of the alkenyl-containing organic monomer is preferably 16.5% to 17% of the mass of the alcohol organic solvent. The present invention controls the content within the above range to facilitate injection molding of ceramics.

[0032] In the present invention, the cross-linking agent preferably includes one or more of methylenebisacrylamide, N,N-dimethylacrylamide and ethylene glycol dimethacrylate; the mass of the cross-linking agent is preferably 5% to 6% of the mass of the olefinic organic monomer. The present invention controls the cross-linking agent within the above range to facilitate the formation of a continuous three-dimensional ceramic dense skeleton.

[0033] In the present invention, the alcohol organic solvent is preferably tert-butanol; the mass content of tert-butanol in the premix is ​​preferably 40% to 80%, specifically 43%, 50%, 59% or 70%.

[0034] In the present invention, the lead zirconate titanate powder is preferably a submicron powder with a particle size of approximately 200 nm; the purity of the lead zirconate titanate powder is preferably greater than 99.9%. The mass content of the lead zirconate titanate powder in the premix is ​​preferably 15% to 50%, specifically 18%, 31%, 41%, or 49%. This mass content of lead zirconate titanate powder results in a porous lead zirconate titanate piezoelectric ceramic with excellent performance, ease of injection molding, and resistance to cracking.

[0035] In the present invention, the dispersant preferably includes one or more of ammonium polyacrylate, ammonium citrate and ammonium tripolyphosphate; the mass of the dispersant is preferably 0.3% to 1.5% of the total mass of the lead zirconate titanate powder, the olefinic organic monomer and the cross-linking agent, specifically 0.3%, 0.5% or 1.5%.

[0036] In the present invention, the total mass content of the lead zirconate titanate powder, the olefinic organic monomer and the cross-linking agent in the premix is ​​preferably 20% to 50%.

[0037] In the present invention, the grinding is preferably ball milling, and the rotation speed of the ball mill is preferably 300 r / min; the ball milling time is 8 to 15 hours, specifically 10 hours, 11 hours or 12 hours; the mass ratio of powder to ball milling beads during the ball milling process is preferably 1:1.5.

[0038] After obtaining the premix, the present invention removes bubbles from the premix, and then mixes the premix with an initiator and an amine catalyst to carry out polymerization reaction to obtain a gel body.

[0039] In the present invention, the bubbles are preferably removed by vacuuming.

[0040] In the present invention, the amine catalyst preferably includes tetramethylethylenediamine and / or triethanolamine. The amine catalyst is preferably used in the form of an amine catalyst tert-butanol solution. The mass ratio of the amine catalyst to tert-butanol in the amine catalyst tert-butanol solution is preferably 1:9. The mass of the amine catalyst tert-butanol solution is preferably 25% to 35% of the mass of the alkenyl-containing organic monomer, specifically 30%.

[0041] In the present invention, the initiator preferably includes ammonium persulfate and / or benzoyl peroxide, and the initiator is preferably used in the form of an initiator solution. The mass ratio of the initiator to water in the initiator solution is preferably 2:3; the mass of the initiator solution is preferably 35% to 40% of the mass of the olefinic organic monomer, specifically 37.5%.

[0042] In the present invention, the polymerization reaction temperature is preferably 35-45°C, specifically 40°C, and the polymerization reaction time is preferably 20-40 minutes, specifically 30 minutes. The polymerization reaction is preferably carried out in a mold with a lid. During the polymerization reaction, the alkenyl-containing organic monomers react with each other to form a polymer chain structure. Under the action of the crosslinking agent, the polymer chains react with each other to form a three-dimensional network structure.

[0043] In the present invention, after the polymerization reaction, the steps of removing the solvent and demoulding are preferably further included; the temperature for removing the solvent is preferably 35 to 45° C., specifically 40° C., and the time is preferably 1.5 to 2 hours.

[0044] After obtaining the gel body, the present invention sequentially dries and sinters the gel body to obtain the lead zirconate titanate porous piezoelectric ceramic.

[0045] In the present invention, the drying temperature is preferably 40 to 50° C., and the drying time is preferably 16 to 24 hours.

[0046] In the present invention, the drying step preferably includes debinding, and the debinding temperature is preferably 620-650° C., and the debinding time is preferably 24-58 hours.

[0047] In the present invention, the sintering temperature is preferably 1250-1350° C., specifically 1250° C. or 1300° C., the holding time is preferably 3-5 hours, specifically 4 hours, and the sintering is preferably performed in an air atmosphere.

[0048] The present invention provides a lead zirconate titanate porous piezoelectric ceramic obtained by the preparation method described in the above technical solution, which has a porosity of 45% to 65%, a dielectric constant of 190 to 910, a piezoelectric charge coefficient of 120 to 360 pC / N, and a piezoelectric voltage coefficient of 40×10 -3 ~90×10 -3 Vm / N, energy harvesting quality factor is 9×10 -12 ~21×10 -12 m 2 / N.

[0049] In the present invention, the porosity of the lead zirconate titanate porous piezoelectric ceramic is preferably 45.40% to 64.87%, the dielectric constant is preferably 190.83 to 902.35, the piezoelectric charge coefficient is preferably 129.42 to 351 pC / N, and the piezoelectric voltage coefficient is preferably 43.95×10 -3 ~81.71×10 -3 Vm / N, the energy harvesting quality factor is preferably 9.95×10 -12 ~20.28×10 -12 m 2 / N.

[0050] The present invention provides the application of the lead zirconate titanate porous piezoelectric ceramics described in the above technical solution in sensitive output and energy harvesting materials.

[0051] The lead zirconate titanate porous piezoelectric ceramics of the present invention have a porous structure that significantly reduces the dielectric constant. At the same time, the constructed three-dimensional interconnected structure controls the decrease in the piezoelectric charge coefficient, achieves the decoupling of the piezoelectric charge coefficient and the dielectric constant, and significantly improves the sensitive output and energy collection performance.

[0052] The energy harvesting quality factor (FOM) is usually used to evaluate the energy harvesting performance of piezoelectric materials. ij ) and piezoelectric voltage coefficient (g ij ), when used for the classical 3-3 mode, can be defined by the following two equations, where the applied force is parallel to the polarization direction d 33 is the longitudinal piezoelectric charge coefficient, g 33 is the piezoelectric voltage coefficient, is the relative dielectric constant at constant pressure, ε0 is the dielectric constant of vacuum, FOM 33 is the energy harvesting quality factor:

[0053]

[0054] As can be seen from the two equations above, a high piezoelectric charge coefficient and a low relative dielectric constant are beneficial for applications related to sensing and energy harvesting. The present invention utilizes a three-dimensional interconnected porous structure to achieve decoupling of the piezoelectric charge coefficient and dielectric constant. The prepared lead zirconate titanate porous piezoelectric ceramic has highly sensitive output and excellent energy harvesting performance. The present invention uses a gel injection molding process to introduce a three-dimensional interconnected porous structure into the piezoelectric ceramic, which not only contributes to the research foundation for achieving material structure-function integration, but also provides an alternative material for the development of piezoelectric energy harvesting technology, which has important scientific significance and engineering application value.

[0055] In order to further illustrate the present invention, the lead zirconate titanate porous piezoelectric ceramics provided by the present invention, and its preparation method and application are described in detail below with reference to the accompanying drawings and examples, but they should not be understood as limiting the scope of protection of the present invention.

[0056] Example 1

[0057] 75.56 g of tert-butanol, 12.47 g of organic monomer acrylamide (16.5% of the mass of tert-butanol), and 0.62 g of methylenebisacrylamide crosslinking agent (5% of the mass of acrylamide) were mixed and stirred with a glass stirring rod for 10 minutes to obtain an organic solution.

[0058] 19.5 g of lead zirconate titanate powder was taken, and the obtained organic solution, lead zirconate titanate powder and 0.16 g of ammonium polyacrylate dispersant (0.5% of the total mass of the material, with the total mass of the lead zirconate titanate powder, organic monomer acrylamide and methylene bisacrylamide crosslinking agent as the total mass of the material) were mixed and ball-milled at a ball milling speed of 300 r / min for 10 h to obtain a premix (the mass content of lead zirconate titanate in the premix was 18%).

[0059] The premix was vacuumed to remove bubbles; 3.74 g of catalyst tetramethylethylenediamine solution (30% by mass of organic monomer acrylamide, with a mass ratio of tetramethylethylenediamine to solvent tert-butyl alcohol of 1:9) was slowly added to the debubbled premix using a rubber dropper and stirred for 5 minutes to mix evenly; 4.68 g of initiator ammonium persulfate solution (37.5% by mass of organic monomer acrylamide, with a mass ratio of ammonium persulfate to solvent deionized water of 2:3) was slowly added to the premix using a rubber dropper and stirred continuously to prevent lumps. The uniformly stirred premix is ​​poured into a mold for gel curing, and the mold is covered and placed in a 40°C oven to undergo polymerization for 30 minutes. After the reaction is complete, the lid is opened to allow the tert-butanol to evaporate completely for 2 hours, and the mold is removed to obtain a ceramic body. The ceramic body is dried, debinded and sintered in sequence to obtain a porous piezoelectric lead zirconate titanate ceramic. The drying temperature is 40°C, the drying time is 24 hours, the debinding temperature is 620°C, the time is 24 hours, the sintering temperature is 1250°C, and the holding time is 4 hours.

[0060] The porosity of the lead zirconate titanate porous piezoelectric ceramics prepared in Example 1 is 64.87%, and the dielectric constant (ε r ) is 190.83, and the piezoelectric charge coefficient (d 33 ) is 129.42pC / N, and the piezoelectric voltage coefficient (g 33 ) is 77.41×10 -3 Vm / N, energy harvesting quality factor (FOM 33 ) is 9.95×10 -12 m 2 / N.

[0061] Example 2

[0062] 73.63 g of tert-butanol, 12.15 g of organic monomer acrylamide (16.5% of the mass of tert-butanol), and 0.61 g of methylenebisacrylamide crosslinking agent (5% of the mass of acrylamide) were mixed and stirred with a glass stirring rod for 10 minutes to obtain an organic solution.

[0063] 39 g of lead zirconate titanate powder was taken, and the obtained organic solution, lead zirconate titanate powder and 0.26 g of ammonium polyacrylate dispersant (0.5% of the total mass of the material, with the total mass of the lead zirconate titanate powder, organic monomer acrylamide and methylene bisacrylamide crosslinking agent as the total mass of the material) were mixed and ball-milled at a ball milling speed of 300 r / min for 12 h to obtain a premix (the mass content of lead zirconate titanate in the premix was 31%).

[0064] The premix was vacuumed to remove bubbles; 3.64 g of catalyst tetramethylethylenediamine solution (30% by mass of organic monomer acrylamide, mass ratio of tetramethylethylenediamine to solvent tert-butyl alcohol was 1:9) was slowly added to the premix after degassing using a rubber dropper and stirred for 5 minutes to mix evenly; 4.56 g of initiator ammonium persulfate solution (37.5% by mass of organic monomer acrylamide, mass ratio of ammonium persulfate to solvent deionized water was 2:3) was slowly added to the premix using a rubber dropper and stirred continuously to avoid lumps. The uniformly stirred premix is ​​poured into a mold for gel curing, and the mold is covered and placed in a 40°C oven to undergo polymerization for 30 minutes. After the reaction is complete, the lid is opened to allow the tert-butanol to evaporate completely for 2 hours, and the mold is removed to obtain a ceramic body. The ceramic body is dried, debinded and sintered in sequence to obtain a porous piezoelectric lead zirconate titanate ceramic. The drying temperature is 40°C, the drying time is 24 hours, the debinding temperature is 620°C, the time is 24 hours, the sintering temperature is 1250°C, and the holding time is 4 hours.

[0065] The porosity of the lead zirconate titanate porous piezoelectric ceramics prepared in Example 2 is 58.77%, the dielectric constant is 343.12, the piezoelectric charge coefficient is 248.13 pC / N, and the piezoelectric voltage coefficient is 81.71×10 -3 Vm / N, the energy harvesting quality factor is 20.28×10 -12 m 2 / N.

[0066] Example 3

[0067] 71.69 g of tert-butanol, 11.83 g of organic monomer acrylamide (16.5% of the mass of tert-butanol), and 0.59 g of methylenebisacrylamide crosslinking agent (5% of the mass of acrylamide) were mixed and stirred with a glass stirring rod for 10 minutes to obtain an organic solution.

[0068] 58.5 g of lead zirconate titanate powder was taken, and the obtained organic solution, lead zirconate titanate powder and 0.36 g of ammonium polyacrylate dispersant (0.5% of the total mass of the material, with the total mass of the lead zirconate titanate powder, organic monomer acrylamide and methylene bisacrylamide crosslinking agent as the total mass of the material) were mixed and ball-milled at a ball milling speed of 300 r / min for 11 h to obtain a premix (the mass content of lead zirconate titanate in the premix was 41%).

[0069] The premix was vacuumed to remove bubbles; 3.55 g of catalyst tetramethylethylenediamine solution (30% by mass of organic monomer acrylamide, with a mass ratio of tetramethylethylenediamine to solvent tert-butyl alcohol of 1:9) was slowly added to the debubbled premix using a rubber dropper and stirred for 5 minutes to mix evenly; 4.44 g of initiator ammonium persulfate solution (37.5% by mass of organic monomer acrylamide, with a mass ratio of ammonium persulfate to solvent deionized water of 2:3) was slowly added to the premix using a rubber dropper and stirred continuously to prevent lumps. Appearance; pour the evenly stirred premix into the mold for gel curing, cover it and put it into a 40°C oven to make it undergo polymerization reaction, and the polymerization reaction time is 30 minutes; after the reaction is complete, open the lid to allow the tert-butanol to completely evaporate, the time is 2 hours, and demold to obtain a ceramic embryo; the ceramic embryo is dried, debinded and sintered in sequence to obtain a lead zirconate titanate porous piezoelectric ceramic, the drying temperature is 40°C, the drying time is 24 hours, the debinding temperature is 620°C, the time is 24 hours, the sintering temperature is 1300°C, and the holding time is 3 hours.

[0070] The porosity of the lead zirconate titanate porous piezoelectric ceramics prepared in Example 3 is 52.02%, the dielectric constant is 793, the piezoelectric charge coefficient is 330.46 pC / N, and the piezoelectric voltage coefficient is 47.08×10 -3 Vm / N, the energy harvesting quality factor is 15.56×10 -12 m 2 / N.

[0071] Example 4

[0072] 69.75 g of tert-butanol, 11.51 g of organic monomer acrylamide (16.5% of the mass of tert-butanol), and 0.58 g of methylenebisacrylamide crosslinking agent (5% of the mass of acrylamide) were mixed and stirred with a glass stirring rod for 10 minutes to obtain an organic solution.

[0073] 78 g of lead zirconate titanate powder was taken, and the obtained organic solution, lead zirconate titanate powder and 0.80 g of ammonium polyacrylate dispersant (0.5% of the total mass of the material, with the total mass of the lead zirconate titanate powder, organic monomer acrylamide and methylene bisacrylamide crosslinking agent as the total mass of the material) were mixed and ball-milled at a ball milling speed of 300 r / min for 10 h to obtain a premix (the mass content of lead zirconate titanate in the premix was 49%).

[0074] The premix was vacuumed to remove bubbles; 3.45 g of catalyst tetramethylethylenediamine solution (30% by mass of organic monomer acrylamide, mass ratio of tetramethylethylenediamine to solvent tert-butyl alcohol was 1:9) was slowly added to the debubbled premix using a rubber dropper and stirred for 5 minutes to mix evenly; 4.42 g of initiator ammonium persulfate solution (37.5% by mass of organic monomer acrylamide, mass ratio of ammonium persulfate to solvent deionized water was 2:3) was slowly added to the premix using a rubber dropper and stirred continuously to prevent lumps from forming. Now, pour the evenly stirred premix into the mold for gel curing, cover it and put it into a 40℃ oven to make it undergo polymerization reaction, and the polymerization reaction time is 30 minutes; after the reaction is complete, open the lid to allow the tert-butanol to completely evaporate, the time is 1.5 hours, and demold to obtain a ceramic embryo; the ceramic embryo is dried, debinded and sintered in sequence to obtain lead zirconate titanate porous piezoelectric ceramics, the drying temperature is 40℃, the drying time is 24 hours, the debinding temperature is 620℃, the time is 24 hours, the sintering temperature is 1350℃, and the holding time is 4 hours.

[0075] The porosity of the lead zirconate titanate porous piezoelectric ceramics prepared in Example 4 is 45.40%, the dielectric constant is 902.35, the piezoelectric charge coefficient is 351 pC / N, and the piezoelectric voltage coefficient is 43.95×10 -3 Vm / N, the energy harvesting quality factor is 15.42×10 -12 m 2 / N.

[0076] Figure 1 The performance comparison chart of the lead zirconate titanate porous piezoelectric ceramics prepared in Examples 1 to 4 is shown in FIG. Figure 1 It can be seen that the porous piezoelectric ceramics prepared in Example 2 have the highest piezoelectric voltage coefficient and energy harvesting quality factor. As the lead zirconate titanate content increases, the piezoelectric charge coefficient increases and the dielectric constant increases. The increase in the piezoelectric charge coefficient of Example 2 is greater than the dielectric constant. From the formulas for the piezoelectric voltage coefficient and the energy harvesting quality factor, it can be seen that the four examples have the best electrical performance. Compared with dense ceramics, the introduction of the porous structure achieves the decoupling of the piezoelectric charge coefficient and the dielectric constant. At the same time, the three-dimensional network structure obtained by the gel injection molding method can achieve more efficient charge and stress transmission.

[0077] Figure 2 This is an SEM image of the porous lead zirconate titanate piezoelectric ceramic prepared in Example 2. The prepared porous piezoelectric ceramic has a uniform pore distribution and a 3-3 interconnected structure, resulting in excellent piezoelectric properties. The pore size ranges from 10 to 100 microns. It can be seen that the precipitation polymerization of acrylamide / methylenebisacrylamide in tert-butyl alcohol produces small gel particles with thin gel walls.

[0078] Comparative Example 1: Pore-forming agent method

[0079] Reference "Yan M, Liu S, Xiao Z, et al. Evaluation of the pore morphologies for piezoelectric energy harvesting application [J]. Ceramics International, 2022, 48(4): 5017-5025."

[0080] Lead zirconate titanate powder was ball-milled at 300 rpm for 24 hours. The milled lead zirconate titanate ceramic powder (83 vol%) was mixed with 17 μm diameter polymethyl methacrylate (PMMA) beads (17 vol%) and uniaxially hydraulically pressed at a pressure of 200 MPa to produce a piezoelectric ceramic green body with an initial diameter of 12 mm and a thickness of 1.0 mm. The green body was then sintered at 1350°C for 3 hours to obtain a porous lead zirconate titanate ceramic with spherical and elliptical pores.

[0081] Comparative Example 2 Freeze Drying

[0082] Reference "Yan M, Liu S, Xiao Z, et al. Evaluation of the pore morphologies for piezoelectric energy harvesting application [J]. Ceramics International, 2022, 48(4): 5017-5025."

[0083] Lead zirconate titanate powder (48 vol%) and deionized water were ball-milled at a speed of 300 r / min for 24 h. The suspension was poured into a cylindrical polydimethylsiloxane (PDMS) mold ( The samples were then freeze-dried in a liquid nitrogen container with a temperature gradient to form directional pores. The samples were then freeze-dried under vacuum conditions, allowing the ice crystals to sublime at 25°C and 1 Pa for 48 hours. Finally, the porous lead zirconate titanate ceramics were sintered at 1350°C for 3 hours.

[0084] Comparative Example 3 Direct Writing

[0085] Reference "LI Z.,LI J.,LUO H.,et al.Direct inkwriting of3D piezoelectricceramics with complex unsupported structures[J].2022,42(9):3841-3847."

[0086] Lead zirconate titanate powder was dispersed in a mixture of xylene and ethanol (15-10 wt% of the lead zirconate titanate powder mass), and triethyl phosphate (TEP) (1 wt% of the lead zirconate titanate powder mass) was added as a dispersant. The premixed suspension was transferred to a Teflon bottle with zirconium oxide balls as the mixing medium and then mixed with a ball mill at 80 rpm for 24 hours. The mass ratio of grinding balls to powder was maintained at 3:1. Subsequently, polyethylene glycol (PEG) and dibutyl phthalate (DBP) (11 wt% of the lead zirconate titanate powder mass) were added as plasticizers, and polyvinyl butyral (PVB) (5 wt% of the lead zirconate titanate powder mass) was used as a binder, and then ball milling was continued for another 24 hours. After magnetic stirring and heating in air, the solvent evaporated to achieve the predetermined 80 wt% solid content and appropriate viscoelasticity of the slurry. Finally, the resulting ink was loaded into a syringe barrel (10 mL) for direct writing. Before printing, the suspension was centrifuged at 2000 rpm for 2 minutes to defoam. The printed green sample was dried in an oven at 60°C for 1 hour and removed from the glass substrate after cooling. The green sample was then twisted, bent, or formed with the help of a support to create specialized structures that are difficult to achieve using traditional DIW methods.

[0087] The dried green sample was heated at 325 °C and 500 °C for 1 h in a lead-rich atmosphere for organic decomposition and sintered at 1350 °C for 2 h.

[0088] Table 1 shows the properties of lead zirconate titanate piezoelectric ceramics obtained by different preparation methods:

[0089] Table 1 Comparison of performance of lead zirconate titanate (PZT) piezoelectric ceramics

[0090]

[0091] As can be seen from Table 1, the present invention adopts the gel injection molding method to prepare the lead zirconate titanate porous piezoelectric ceramics, which can achieve the improvement of sensitive transmission and energy collection performance.

[0092] Although the above embodiments provide a detailed description of the present invention, they are only part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on the embodiments of the present invention without creative work, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a porous lead zirconate titanate piezoelectric ceramic, characterized in that: The following steps are involved: An olefin-containing organic monomer, a cross-linking agent, an alcohol organic solvent, lead zirconate titanate powder and a dispersant are mixed and ground to obtain a premix; After removing bubbles from the premix, the premix is ​​mixed with an initiator and an amine catalyst to carry out a polymerization reaction to obtain a gel body; The gel blank is dried and sintered in sequence to obtain a lead zirconate titanate porous piezoelectric ceramic.

2. The preparation method according to claim 1, characterized in that The mass content of the lead zirconate titanate powder in the premix is ​​15% to 50%.

3. The preparation method according to claim 1, characterized in that The alkenyl-containing organic monomer comprises one or more of acrylamide, styrene and methyl methacrylate; the mass of the alkenyl-containing organic monomer is 16.5% to 17% of the mass of the alcohol organic solvent.

4. The preparation method according to claim 1 or 3, characterized in that The cross-linking agent comprises one or more of methylene bisacrylamide, N,N-dimethylacrylamide and ethylene glycol dimethacrylate; the mass of the cross-linking agent is 5% to 6% of the mass of the alkenyl-containing organic monomer.

5. The preparation method according to claim 1, characterized in that The dispersant comprises one or more of ammonium polyacrylate, ammonium citrate and ammonium tripolyphosphate; the mass of the dispersant is 0.3% to 1.5% of the total mass of the lead zirconate titanate powder, the olefin-containing organic monomer and the crosslinking agent.

6. The preparation method according to claim 1 or 3, characterized in that The amine catalyst comprises tetramethylethylenediamine and / or triethanolamine; the mass of the amine catalyst is 2.5% to 3.5% of the mass of the alkenyl-containing organic monomer.

7. The preparation method according to claim 1 or 3, characterized in that The initiator comprises ammonium persulfate and / or benzoyl peroxide; the mass of the initiator is 14% to 16% of the mass of the alkenyl-containing organic monomer.

8. The preparation method according to claim 1, characterized in that The sintering temperature is 1250-1350° C., and the holding time is 3-5 hours.

9. The porous lead zirconate titanate piezoelectric ceramic obtained by the preparation method according to any one of claims 1 to 8, characterized in that: The porosity is 45% to 65%, the dielectric constant is 190 to 910, the piezoelectric charge coefficient is 120 to 360 pC / N, and the piezoelectric voltage coefficient is 40×10 -3 ~90×10 -3 Vm / N, energy harvesting quality factor is 9×10 -12 ~21×10 -12 m 2 / N.

10. Use of the lead zirconate titanate porous piezoelectric ceramic according to claim 9 in sensitive output and energy harvesting materials.

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