PZT-5A porous piezoelectric ceramic material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of piezoelectric ceramic material research, and particularly relates to a PZT-5A porous piezoelectric ceramic material as well as a preparation method and application thereof. The PZT-5A porous piezoelectric ceramic material is prepared from the following raw materials: PZT-5A powder, nano carbon black, a dispersing agent and an organic carrier, wherein the mass ratio of the PZT-5A powder to the nano carbon black is 228: (9-11), and the mass of the dispersing agent is 1%-2.5% of the total mass of the PZT-5A powder and the nano carbon black. The invention provides a PZT-5A porous piezoelectric ceramic material as well as a preparation method and application thereof, PZT-5A powder is adopted, nano carbon black is used as a sacrificial template, a uniform porous structure with the porosity of about 25% and the aperture of 1-5 microns is prepared, and the PZT-5A porous piezoelectric ceramic material is suitable for application scenes such as ultrasonic sensing, broadband piezoelectric transducers and energy collection.

Description

Technical Field

[0001] The present invention belongs to the technical field of piezoelectric ceramic material research, and in particular relates to a PZT-5A porous piezoelectric ceramic material, a preparation method and an application thereof. Background Art

[0002] The widespread application of ultrasonic sensors, broadband transducers, and piezoelectric energy harvesting devices in fields such as industrial nondestructive testing, medical ultrasound imaging, and structural health monitoring has placed higher demands on the bandwidth characteristics, sensitivity, and energy dissipation performance of piezoelectric ceramic materials. While traditional dense PZT-based piezoelectric ceramics possess excellent energy-gathering capabilities due to their inherently high mechanical quality factor (Qm), they also exhibit inherent drawbacks such as narrow bandwidth and insufficient mechanical damping, severely restricting their application in broadband excitation or pulsed drive scenarios.

[0003] In order to break through the above bottlenecks, the industry has proposed a porous preparation strategy, and the mainstream methods include sacrificial template method, direct pore-forming agent method, foaming method and ice template method. Among them, the sacrificial template method constructs a porous structure by pre-setting organic / inorganic templates (such as organic polymer microspheres, sawdust, surfactants, etc.), which has the significant advantage of controllable pore morphology. However, due to the problems of coarse particle size and insufficient dispersion uniformity in the existing template system, it is easy to cause residue accumulation or matrix cracking in the degreasing process stage, which directly affects the electrical performance stability and mechanical reliability of the material. Reference patent document CN118388259A discloses a method for rapid degreasing of ceramic injection molded blanks, which adopts a template method to prepare a porous ceramic membrane material with precisely controllable pore size and pore gradient distribution; according to the three-dimensional appearance of the injection molded blank, a gradient porous ceramic membrane stage for carrying the injection blank is accurately made; then the injection blank is placed on the processed stage, and then the precisely processed gradient porous ceramic membrane is matched above the blank. TG-DSC analysis of the ceramic injection feed was performed, and precise degreasing process parameters were designed based on the TG-DSC analysis results. By using a gradient ceramic membrane with a multi-level vertical pore size design as a siphon during the degreasing process, the pore size of the ceramic membrane is precisely controlled, and the pore size presents a gradient distribution, which greatly accelerates the siphoning process and decomposition and diffusion process of organic matter, significantly improving degreasing efficiency. CN101391892A also discloses a method for preparing porous piezoelectric ceramics with high porosity, which comprises weighing a pore-forming agent, a monomer, and a cross-linking agent in proportion and magnetically stirring the mixture to obtain a premix; adding lead zirconate titanate ceramic powder and a dispersant to the premix, ball milling the mixture to obtain a lead zirconate titanate ceramic suspension slurry, and then adding a catalyst and an initiator in sequence, stirring the mixture evenly, and injecting the mixture into a mold, whereby the monomer and the cross-linking agent undergo a polymerization reaction to generate a long-chain high molecular polymer in the slurry, and the lead zirconate titanate particles are in situ solidified to obtain a high-strength lead zirconate titanate ceramic green body; and the green body undergoes demolding, drying, heating, and sintering steps to obtain a porous lead zirconate titanate piezoelectric ceramic material.

[0004] However, in practical applications, the above-mentioned prior art still has the following technical problems:

[0005] 1) The particle size of traditional templates is mostly above the micron level, which makes it difficult to construct uniform and fine microporous structures, resulting in poor controllability of pore size and distribution;

[0006] 2) After degreasing, conventional templates are prone to residual carbide or ash impurities, which significantly increase the dielectric loss of the material and reduce the volume resistivity;

[0007] 3) In the existing technology, when the porosity is increased to expand the bandwidth, the mechanical quality factor Qm value and the piezoelectric coefficient d 33 The simultaneous attenuation of the dielectric constant and the value of the dielectric constant causes the output signal amplitude to decrease, forming a prominent contradiction between "bandwidth and gain";

[0008] 4) The by-products during the high-temperature decomposition of organic templates are complex and may release toxic gases. In addition, the process cost is high, making it difficult to meet the needs of large-scale production.

[0009] Based on the above problems, how to provide a PZT-5A porous piezoelectric ceramic material and preparation method with simple process, which can reduce Qm and improve bandwidth performance while maintaining porosity and structural uniformity is the focus of current research. Summary of the Invention

[0010] In order to address the shortcomings of the existing technology, the present invention provides a PZT-5A porous piezoelectric ceramic material, a preparation method and an application. PZT-5A powder is used, and nano-carbon black is used as a sacrificial template to prepare a uniform porous structure with a porosity of approximately 25% and a pore size of 1μm-5μm. The structure is suitable for application scenarios such as ultrasonic sensing, broadband piezoelectric transducers and energy harvesting.

[0011] The technical means adopted in the present invention are:

[0012] A PZT-5A porous piezoelectric ceramic material is prepared from the following raw materials: PZT-5A powder, nano-carbon black, a dispersant, and an organic carrier; wherein the mass ratio of PZT-5A powder to nano-carbon black is 228:(9-11), and the mass of the dispersant is 1%-2.5% of the total mass of the PZT-5A powder and the nano-carbon black.

[0013] It is further defined that the particle size of the PZT-5A powder is 0.8 μm; and the particle size of the nano carbon black is less than 100 nm.

[0014] It is further defined that the dispersant is polyacrylic acid or D-134C.

[0015] It is further defined that the organic carrier is isopropyl alcohol or anhydrous ethanol.

[0016] It is further defined that the Qm value of the PZT-5A porous piezoelectric ceramic material is 10-30, d33 is at least 480 pC / N; the pore size distribution is 1 μm-5 μm, and the porosity is 20%-25%.

[0017] The preparation method of PZT-5A porous piezoelectric ceramic material consists of the following steps:

[0018] S1: PZT-5A powder, nano-carbon black, and dispersant were taken according to the ratio, placed in a ball mill, and an organic carrier was added. The mixture was ball milled at 200-400 rpm for 3-5 hours. Ultrasonic oscillation was used for degassing to form a slurry. The organic carrier was then added to adjust the slurry viscosity to 2000-3000 mPa·s.

[0019] S2: The slurry obtained in step S1 is shaped and placed at room temperature, and then heated at a rate of ≤1°C·min -1 Preheat to 300℃, keep warm for 1-2 hours, and discharge volatiles;

[0020] S3: According to 0.5℃·min -1 –1℃·min -1 The temperature is raised to 500-600℃ at a heating rate, and then placed into an oxygen-rich atmosphere, kept at this temperature for 4 hours, and then degreased and demoulded;

[0021] S4: The degreased and demoulded material is heated to 1250°C and sintered for 2-4 hours to obtain a porous skeleton. Rapid or segmented cooling is used to control the growth of pore wall grains.

[0022] S5: Place the sintered material at 150℃-200℃, 10kV·mm -1 -15kV·mm -1 Polarize for 15 min to 30 min in an oil bath environment to obtain PZT-5A porous piezoelectric ceramic material.

[0023] It is further defined that in said S1: the ball milling treatment is carried out at 300 rpm for 4 hours; and the ultrasonic oscillation degassing treatment is carried out at 20 kHz to 40 kHz for 20 minutes to 35 minutes.

[0024] Further defined, in said S2, the slurry obtained in step S1 is subjected to isostatic pressing or injection molding at a pressure of 10 MPa, and after being placed at room temperature for 24 hours, the slurry is heated at a rate of ≤1°C min -1 Preheat to 300℃ and keep warm for 1-2 hours.

[0025] It is further defined that in said S3, the temperature is adjusted to 0.5°C·min -1 –1℃·min -1The temperature is raised to 500°C–600°C at a heating rate of 100°C, and an oxygen-rich atmosphere with an oxygen volume concentration of at least 26% is introduced, and the temperature is maintained for 4 hours.

[0026] A sensor device comprises the PZT-5A porous piezoelectric ceramic material, and is applied to an ultrasonic sensor, a broadband piezoelectric transducer, or an energy harvester.

[0027] PZT-5A porous piezoelectric ceramic material has a bandwidth of not less than 40kHz, d 33 Not less than 480 and dielectric constant ε r Applications in 1320 wide-band or pulse drive.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention uses PZT-5A powder and nano-carbon black as raw materials, and uses nano-carbon black (particle size <100nm) as a sacrificial template. The amount of nano-carbon black is precisely controlled, and sintered in an oxygen-rich atmosphere to produce a PZT-5A porous piezoelectric ceramic material with uniform micropores of 1μm-5μm. This material achieves the goal of maintaining d 33 The purpose of improving the bandwidth performance by only reducing the mechanical quality factor Qm of the material while increasing the dielectric constant solves the "bandwidth-gain" contradiction problem existing in porous piezoelectric ceramics in the prior art.

[0030] 2. The PZT-5A porous piezoelectric ceramics of the present invention are degreased and demolded by introducing them into an oxygen-rich atmosphere at 500-600°C, which can completely oxidize and remove carbon black, avoid the reaction of residual carbon with the ceramic matrix, ensure the absence of residual carbon defects, and are evenly dispersed to form interconnected, honeycomb-shaped micropores. The pore walls are interconnected by sintering necks to form a three-dimensional network, ensuring that the pores are concentrated and the pore size distribution is uniform, and having good acoustic properties.

[0031] 3. The PZT-5A porous piezoelectric ceramic material of the present invention can increase the bandwidth by more than 50% when the Qm is 25.09, and the response is smooth and uniform within the entire bandwidth, avoiding excessive saturation at the resonance. When used in ultrasonic sensor devices, it ensures that the post-stage amplifier can always operate in the linear range, with less signal distortion, high-fidelity measurement results, higher sensitivity, clean response to pulse excitation without obvious aftershock, suitable for high-speed pulse drive, and applicable to application scenarios such as ultrasonic sensing, broadband piezoelectric transducers and energy harvesting.

[0032] 4. While ensuring the acoustic performance and strength of the product, the present invention uses simple materials, nano carbon black can be prepared on a large scale at low cost, the molding and degreasing processes are compatible with conventional processes, the overall process is simple, and is suitable for industrial promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a SEM image of the PZT-5A porous piezoelectric ceramic material of the present invention;

[0034] Figure 2 This is an impedance analysis diagram of the PZT-5A porous piezoelectric ceramic material of the present invention;

[0035] Figure 3 This is the impedance analysis diagram of the comparative example PZT-5A piezoelectric ceramic. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to specific embodiments. However, the methods and technical parameters involved in the solutions should not be understood as limiting the present invention.

[0037] PZT-5A piezoelectric ceramics are industrial 5A piezoelectric ceramics, which are mainly used in the fields of electroacoustic and ultrasonic sensors. They have large dielectric loss tanδ and piezoelectric constant d 33 The Kp value of the planar electromechanical coupling coefficient is large, but the weakness of its own material leads to high energy consumption when used at high frequencies, slow vibration attenuation, and greater interference from external signals, especially in wide-band excitation or pulse drive scenarios. Its application is limited.

[0038] The present invention uses PZT-5A powder and nano-carbon black as raw materials, and uses nano-carbon black (particle size <100nm) as a sacrificial template. The amount of nano-carbon black is precisely controlled, and sintered in an oxygen-rich atmosphere to produce a porous piezoelectric ceramic material with uniform micropores concentrated in the range of 1μm-5μm. This achieves the purpose of reducing the material's mechanical quality factor Qm and improving bandwidth performance while maintaining porosity and structural uniformity.

[0039] The present invention discloses a PZT-5A porous piezoelectric ceramic material, which is prepared from the following raw materials: PZT-5A powder, nano-carbon black, a dispersant and an organic carrier; wherein the mass ratio of the PZT-5A powder to the nano-carbon black is 228:(9-11), and the mass of the dispersant is 1%-2.5% of the total mass of the PZT-5A powder and the nano-carbon black.

[0040] For example, the mass ratio of PZT-5A powder to nano-carbon black is 228:9, 228:10, or 228:11. The mass of the dispersant is 1%, 1.5%, 2%, or 2.5% of the total mass of the PZT-5A powder and nano-carbon black.

[0041] It should be noted that the mass of the dispersant defined in the present invention refers to the mass of the solute in the dispersant. In actual operation, if the dispersant is a liquid, the corresponding volume added is calculated based on the density of the purchased dispersant and the mass ratio defined above.

[0042] Preferably, the particle size of the PZT-5A powder is 0.8 μm; and the particle size of the nano carbon black is less than 100 nm.

[0043] In the present invention, PZT-5A powder refers to PZT-5A piezoelectric ceramic powder. PZT-5A powder and nano carbon black are both conventional commercial products. The bulk density of PZT-5A powder is about 3.8 g / cm 3 The bulk density of nano carbon black is 0.5g / cm 3 .

[0044] In the present invention, the dispersant is polyacrylic acid or D-134C.

[0045] Preferably, D-134C is a Japanese imported dispersant purchased from the market.

[0046] In the present invention, the organic carrier is isopropyl alcohol or anhydrous ethanol.

[0047] The PZT-5A porous piezoelectric ceramic material prepared by the above method was tested, and the Qm value was 10-30, d 33 At least 480pC / N; pore size distribution is 1μm-5μm, porosity is 20%-25%. PZT-5A porous piezoelectric ceramic material is used in bandwidth not less than 40kHz, d 33 Not less than 480pC / N and dielectric constant ε r In 1320 wideband or pulse drive.

[0048] The present invention provides a method for preparing a PZT-5A porous piezoelectric ceramic material, which comprises the following steps:

[0049] S1: PZT-5A powder, nano-carbon black, and dispersant were taken according to the ratio, placed in a ball mill, and an organic carrier was added. The mixture was ball milled at 200-400 rpm for 3-5 hours. Ultrasonic oscillation was used to remove agglomerates to form a slurry. The organic carrier was then added to adjust the slurry viscosity to 2000-3000 mPa·s.

[0050] Preferably, the ball milling treatment is carried out at 300 rpm for 4 hours, and the ultrasonic oscillation degassing treatment is carried out at 20 kHz to 40 kHz for 20 minutes to 35 minutes.

[0051] S2: The slurry obtained in step S1 is shaped and placed at room temperature, and then heated at a rate of ≤1°C·min -1 Preheat to 300℃, keep warm for 1-2 hours, and discharge volatiles;

[0052] Preferably, in S2, the slurry obtained in step S1 is subjected to isostatic pressing or injection molding at a pressure of 10 MPa, and after being placed at room temperature for 24 hours, the slurry is heated at a rate of ≤1°C·min -1Preheat to 300℃ and keep warm for 1-2 hours.

[0053] S3: According to 0.5℃·min -1 –1℃·min -1 The temperature is raised to 500-600℃ at a heating rate, and then placed into an oxygen-rich atmosphere, kept at this temperature for 4 hours, and then degreased and demoulded;

[0054] Preferably, in S3, the temperature is adjusted to 0.5°C·min -1 –1℃·min -1 The temperature is raised to 500°C–600°C at a heating rate of 100°C, and an oxygen-rich atmosphere with an oxygen volume concentration of at least 26% is introduced, and the temperature is maintained for 4 hours.

[0055] S4: The degreased and demoulded material is heated to 1250°C and sintered for 2-4 hours to obtain a porous skeleton. Rapid or segmented cooling is used to control the growth of pore wall grains.

[0056] S5: Place the sintered material at 150℃-200℃, 10kV·mm -1 -15kV·mm -1 Polarize for 15 min to 30 min in an oil bath environment to obtain PZT-5A porous piezoelectric ceramic material.

[0057] The present invention also provides a sensor device, which includes a PZT-5A porous piezoelectric ceramic material, and the sensor device is applied to an ultrasonic sensor or a broadband piezoelectric transducer or an energy harvester.

[0058] The technical solution of the present invention is further explained below with reference to embodiments.

[0059] It should be noted that, unless otherwise specified, the drugs, reagents, etc. used in the following examples are all conventional commercial products in the art. For example, PZT-5A powder and nano carbon black are both conventional commercial products.

[0060] It should be noted that, unless otherwise specified, the operating steps used in the following examples are all routine operations, and the testing methods used are all standard testing methods in the field.

[0061] Example 1

[0062] The PZT-5A porous piezoelectric ceramic material provided in this embodiment has the following raw material ratios: 285g of PZT-5A powder, 12.5g of nano-carbon black, 5.95g of polyacrylic acid dispersant accounting for 2% of the total mass of PZT-5A powder and nano-carbon black, and an appropriate amount of isopropyl alcohol.

[0063] The preparation of the PZT-5A porous piezoelectric ceramic material of this embodiment is achieved by the following steps:

[0064] S1: PZT-5A powder, nano-carbon black, and dispersant were weighed according to the above mass, placed in a ZrO2 ball mill, and 100 mL of isopropyl alcohol was added. The mixture was ball milled at 300 rpm for 4 h. Ultrasonic treatment was performed at 20 kHz for 30 min to release and eliminate bubbles or dissolved gases in the liquid and remove agglomerates, thereby improving the uniformity of the liquid and forming a uniform slurry. The viscosity was tested and isopropyl alcohol was added as needed to adjust the slurry viscosity to 3000 mPa·s.

[0065] S2: Place the slurry obtained in step S1 in an isostatic pressing machine and perform molding at a pressure of 10 MPa. Place the slurry at room temperature and then heat it at a rate of 1°C / min. -1 Preheat to 300℃, keep warm for 1h, and discharge volatiles;

[0066] S3: According to 1℃·min -1 The temperature was raised to 550°C at a heating rate of 1000 ℃, kept in an oxygen-rich atmosphere with an oxygen volume fraction of 26% for 4 hours, cooled and taken out to complete the degreasing and demoulding treatment;

[0067] S4: The degreased and demoulded material is heated from room temperature to 1250°C for high-temperature sintering, and kept at this temperature for 2 hours to obtain a porous skeleton. Rapid or segmented cooling is used to control the grain growth of the pore wall.

[0068] S5: The sintered material is placed at 165°C and 12.5kV·mm -1 Polarization was carried out in an oil bath for 30 min to obtain the PZT-5A porous piezoelectric ceramic material.

[0069] See also Figure 1 SEM analysis of the PZT-5A porous piezoelectric ceramic material obtained in this example showed interconnected, honeycomb-like micropores, with pore walls interconnected by sintered necks to form a three-dimensional network. The pore size was mainly concentrated in the range of 1μm-5μm and was evenly distributed. The porosity was 25.1%, with no through-hole cracks or abnormally large pores. The pore size uniformity was good, and the pore size and pore size fell within the ideal range. No nanocarbon black residue was observed, indicating that the template was evenly dispersed and the nanocarbon black was completely burned out. Further impedance analysis was performed on this material, and the results are shown in the figure. Figure 2 , its mechanical quality factor Qm is 25.09, and its piezoelectric coefficient d 33 is 480pC / N, the dielectric constant ε r The value of the frequency is 1320, the Kp value is 0.577, and the Fp value is 1050000Hz.

[0070] Example 2

[0071] The PZT-5A porous piezoelectric ceramic material provided in this embodiment has the following raw material ratios: 285 g of PZT-5A powder, 12.5 g of nano-carbon black, 2.975 g of polyacrylic acid dispersant, and an appropriate amount of isopropyl alcohol.

[0072] The preparation of the PZT-5A porous piezoelectric ceramic material of this embodiment is achieved by the following steps:

[0073] S1: PZT-5A powder, nano-carbon black, and dispersant were weighed according to the above mass, placed in a ZrO2 ball mill, and 120 mL of isopropyl alcohol was added. The mixture was ball milled at 200 rpm for 5 h. Ultrasonic treatment was performed at 30 kHz for 25 min. Ultrasonic treatment was used to release and eliminate bubbles or dissolved gases in the liquid and remove agglomerates, thereby improving the uniformity of the liquid and forming a uniform slurry. The viscosity was tested and isopropyl alcohol was added as needed to adjust the slurry viscosity to 2000 mPa·s.

[0074] S2: Place the slurry obtained in step S1 in an isostatic pressing machine and perform molding at a pressure of 10 MPa. Place the slurry at room temperature and then heat it at a rate of 0.9°C / min. -1 Preheat to 300°C, keep warm for 1.2 hours, and discharge volatiles;

[0075] S3: According to 0.5℃·min -1 The temperature was raised to 500°C at a heating rate of 1000°C, kept in an oxygen-rich atmosphere with an oxygen volume fraction of 26% for 4 hours, cooled and taken out to complete the degreasing and demoulding treatment;

[0076] S4: The degreased and demoulded material is heated from room temperature to 1250°C for high-temperature sintering, and kept at this temperature for 3 hours to obtain a porous skeleton. Rapid or segmented cooling is used to control the growth of pore wall grains.

[0077] S5: The sintered material is placed at 150°C, 10kV·mm -1 Polarization was carried out in an oil bath for 30 min to obtain the PZT-5A porous piezoelectric ceramic material.

[0078] After testing, the porosity of the obtained material is 20.2%, the mechanical quality factor Qm is 29.9, and the piezoelectric coefficient d 33 It is 489pC / N.

[0079] Example 3

[0080] The PZT-5A porous piezoelectric ceramic material provided in this embodiment has the following raw material ratios: 285 g of PZT-5A powder, 11.25 g of nano-carbon black, 5.925 g of polyacrylic acid dispersant, and an appropriate amount of isopropyl alcohol.

[0081] The preparation of the PZT-5A porous piezoelectric ceramic material of this embodiment is achieved by the following steps:

[0082] S1: PZT-5A powder, nano-carbon black, and dispersant were weighed according to the above mass, placed in a ZrO2 ball mill, and 80 mL of isopropyl alcohol was added. The mixture was ball milled at 400 rpm for 3 h. Ultrasonic treatment was performed at 40 kHz for 35 min. Ultrasonic treatment was used to release and eliminate bubbles or dissolved gases in the liquid and remove agglomerates, thereby improving the uniformity of the liquid and forming a uniform slurry. The viscosity was tested and isopropyl alcohol was added as needed to adjust the slurry viscosity to 3000 mPa·s.

[0083] S2: Place the slurry obtained in step S1 in an isostatic pressing machine and perform molding at a pressure of 10 MPa. Place the slurry at room temperature and then heat it at a rate of 0.8°C / min. -1 Preheat to 300℃, keep warm for 2h, and discharge volatiles;

[0084] S3: According to 1℃·min -1 The temperature was raised to 600°C at a heating rate of 10000 °C, kept in an oxygen-rich atmosphere with an oxygen volume fraction of 26% for 4 hours, cooled and taken out to complete the degreasing and demoulding treatment;

[0085] S4: The degreased and demoulded material is heated from room temperature to 1250°C for high-temperature sintering, and kept at this temperature for 3 hours to obtain a porous skeleton. Rapid or segmented cooling is used to control the growth of pore wall grains.

[0086] S5: The sintered material is placed in a 200℃, 15kV·mm -1 Polarization was performed in an oil bath for 15 min to obtain PZT-5A porous piezoelectric ceramic material.

[0087] After testing, the porosity of the obtained material is 22%, the mechanical quality factor Qm is 10.8, and the piezoelectric coefficient d 33 It is 491pC / N.

[0088] In order to further verify the performance advantages of the PZT-5A porous piezoelectric ceramic material obtained in the present invention, the inventors used the conventional firing process of PZT-5A piezoelectric ceramic material as a comparative example and conducted impedance analysis on it, as follows:

[0089] Comparative Example:

[0090] The preparation process of Example 1 is referred to, except that in step S3, the temperature is adjusted to 1°C·min. -1 The temperature was raised to 600° C. at a heating rate of 100° C. and kept under vacuum for 4 h. The other steps were the same as those in Example 1.

[0091] The impedance analysis is shown in Figure 3 , the Qm value of the comparative example is 65.47, Kp is 0.435, and Fp is 1057400.0Hz.

[0092] Further Figure 3 and Figure 2 From the comparison, it can be seen that for the material of the comparative example, the damping is smaller, the vibration decays slowly, and the aftershock time is longer; while the damping of Example 1 is larger, the vibration aftershock disappears quickly, and it is suitable for application scenarios with higher precision time resolution; the bandwidth of Example 1 is about 2.6 times the bandwidth of the comparative example, so the material of Example 1 of the present invention is more suitable for covering a wide frequency range. From the comparison of pulse response and peak sensitivity, the material of the comparative example may interfere with subsequent signals due to the continuous aftershock, and can accumulate more energy at the resonant frequency, with a higher output peak, but the peak value drops sharply after deviating from the resonant frequency; while Example 1 responds cleanly to pulse excitation without obvious aftershock, which is very suitable for high-speed pulse drive, and the peak response is smoother and more uniform within the entire bandwidth. The gentle peak avoids excessive saturation at the resonance, allowing the post-amplifier to always operate in the linear range, with less signal distortion and high-fidelity measurement results.

[0093] It is worth noting that the above tests were conducted on the PZT-5A porous piezoelectric ceramic material prepared in Example 1. By replacing the raw material ratio and preparation parameters in Example 1, the PZT-5A porous piezoelectric ceramic material was obtained, and its performance was equivalent to that of Example 1.

[0094] It can be seen from this that the PZT-5A porous piezoelectric ceramic material of the present invention not only meets the porosity requirements, but also maintains d 33 and dielectric constant, reducing the mechanical quality factor Qm of the material, thereby improving the bandwidth performance, making PZT-5A porous piezoelectric ceramic material more suitable for application scenarios such as ultrasonic sensing, broadband piezoelectric transducers and energy harvesting.

[0095] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A PZT-5A porous piezoelectric ceramic material, characterized by: The invention is prepared from the following raw materials: PZT-5A powder, nano-carbon black, dispersant and organic carrier; wherein the mass ratio of PZT-5A powder to nano-carbon black is 228:(9-11), and the mass of the dispersant is 1%-2.5% of the total mass of PZT-5A powder and nano-carbon black.

2. The PZT-5A porous piezoelectric ceramic material according to claim 1, characterized in that: The particle size of the PZT-5A powder is 0.8 μm; the particle size of the nano carbon black is less than 100 nm.

3. The PZT-5A porous piezoelectric ceramic material according to claim 1, characterized in that: The dispersant is polyacrylic acid or D-134C.

4. The PZT-5A porous piezoelectric ceramic material according to claim 1, characterized in that: The organic carrier is isopropyl alcohol or anhydrous ethanol.

5. The PZT-5A porous piezoelectric ceramic material according to any one of claims 1 to 4, characterized in that: The PZT-5A porous piezoelectric ceramic material has a Qm value of 10-30, a d33 value of at least 480 pC / N, a pore size distribution of 1 μm-5 μm, and a porosity of 20%-25%.

6. The method for preparing the PZT-5A porous piezoelectric ceramic material according to claim 5, characterized in that: It consists of the following steps: S1: PZT-5A powder, nano-carbon black, and dispersant were taken according to the ratio, placed in a ball mill, and an organic carrier was added. The mixture was ball milled at 200-400 rpm for 3-5 hours. Ultrasonic oscillation was used for degassing to form a slurry. The organic carrier was then added to adjust the slurry viscosity to 2000-3000 mPa·s. S2: The slurry obtained in step S1 is shaped and placed at room temperature, and then heated at a rate of ≤1°C·min -1 Preheat to 300℃, keep warm for 1-2 hours, and discharge volatiles; S3: According to 0.5℃·min -1 –1℃·min -1 The temperature is raised to 500-600℃ at a heating rate, and then placed into an oxygen-rich atmosphere, kept at this temperature for 4 hours, and then degreased and demoulded; S4: The degreased and demoulded material is heated to 1250°C and sintered for 2-4 hours to obtain a porous skeleton. Rapid or segmented cooling is used to control the growth of pore wall grains. S5: Place the sintered material at 150℃-200℃, 10kV·mm -1 -15kV·mm -1 Polarize for 15 min to 30 min in an oil bath environment to obtain PZT-5A porous piezoelectric ceramic material.

7. The method for preparing the PZT-5A porous piezoelectric ceramic material according to claim 6, characterized in that: In S1: ball milling at 300 rpm for 4 hours; ultrasonic degassing at 20 kHz to 40 kHz for 20 minutes to 35 minutes; In step S2, the slurry obtained in step S1 is subjected to isostatic pressing or injection molding at a pressure of 10 MPa, and after being placed at room temperature for 24 hours, the slurry is heated at a rate of ≤1°C min -1 Preheat to 300℃ and keep warm for 1-2 hours.

8. The method for preparing the PZT-5A porous piezoelectric ceramic material according to claim 6, characterized in that: In S3, the temperature was adjusted to 0.5°C·min. -1 –1℃·min -1 The temperature is raised to 500°C–600°C at a heating rate of 100°C, and an oxygen-rich atmosphere with an oxygen volume concentration of at least 26% is introduced, and the temperature is maintained for 4 hours.

9. A sensor device, characterized in that: The sensor device comprises the PZT-5A porous piezoelectric ceramic material according to claim 1, and the sensor device is applied to an ultrasonic sensor or a broadband piezoelectric transducer or an energy harvester.

10. The PZT-5A porous piezoelectric ceramic material according to claim 1 has a bandwidth of not less than 40 kHz, d 33 Not less than 480 and dielectric constant ε r Applications in 1320 wide-band or pulse drive.

Images