Barium titanate-based piezoelectric ceramic as well as preparation method and application thereof

Abstract

The invention discloses barium titanate-based piezoelectric ceramic, a preparation method and application thereof. The method comprises the following steps: pretreating a barium compound, a titanium compound, a calcium compound, a zirconium compound and a manganese compound; pre-sintering the pretreated barium compound, titanium compound, calcium compound, zirconium compound and manganese compound to form powder; performing granulation on the powder material so as to obtain a granular material; the granules are pressed, so that a blank is formed; sintering the blank to obtain a ceramic precursor; and carrying out polarization and aging treatment on the ceramic precursor to obtain the barium titanate-based piezoelectric ceramic. The piezoelectric coefficient of the barium titanate-based piezoelectric ceramic can be improved, and the hysteresis degree can be reduced.

Description

Technical Field

[0001] The present disclosure belongs to the field of electronic ceramic materials, and specifically relates to a barium titanate-based piezoelectric ceramic, a preparation method and applications thereof. Background Art

[0002] The miniaturization of electronic and power systems is placing higher demands on piezoelectric materials, particularly in piezoelectric sensors and actuators, which demand new materials with high piezoelectric coefficients and low hysteresis. Traditional barium titanate (BaTiO3)-based piezoelectric ceramics, due to their low piezoelectric coefficient (typically in the 100-200pC / N range) and high hysteresis (typically around 25%), are no longer able to meet the demands of high-performance devices.

[0003] In order to improve the piezoelectric properties of barium titanate-based ceramics, researchers have made various attempts. Through process optimization, the piezoelectric coefficient of barium titanate-based ceramics can be improved to a certain extent, but it is often accompanied by a high hysteresis, which affects the actual application effect of the material in sensors and actuators. In addition, other methods of improving the piezoelectric coefficient involve complex process flows, which are difficult to achieve large-scale production, or the prepared materials are insufficiently stable and have poor repeatability.

[0004] Therefore, developing a barium titanate-based piezoelectric ceramic that has both high piezoelectric coefficient and low hysteresis characteristics, and has a simple preparation process and good repeatability has become an important topic in materials science research. Summary of the Invention

[0005] In order to overcome the above problems, the present disclosure proposes a barium titanate-based piezoelectric ceramic, a preparation method and an application thereof. The present disclosure can improve the piezoelectric coefficient of the barium titanate-based piezoelectric ceramic and reduce the hysteresis.

[0006] Specifically, the purpose of this disclosure is to provide the following technical solutions:

[0007] A barium titanate-based piezoelectric ceramic having the following expression: (1-x)(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-xMn, where the value of x is: 0.001~0.01.

[0008] The present disclosure also provides a method for preparing barium titanate-based piezoelectric ceramics, the method comprising: pre-treating a barium compound, a titanium compound, a calcium compound, a zirconium compound, and a manganese compound; pre-calcining the pre-treated barium compound, titanium compound, calcium compound, zirconium compound, and manganese compound to form a powder; granulating the powder to obtain granules; pressing the granules to form a blank; sintering the blank to obtain a ceramic precursor; and polarizing and aging the ceramic precursor to obtain a barium titanate-based piezoelectric ceramic.

[0009] Optionally, the barium compound, titanium compound, calcium compound, zirconium compound and manganese compound are pretreated, including: ball milling the barium compound, titanium compound, calcium compound, zirconium compound and manganese compound; drying the ball-milled barium compound, titanium compound, calcium compound, zirconium compound and manganese compound; and screening the dried barium compound, titanium compound, calcium compound, zirconium compound and manganese compound.

[0010] Optionally, the pre-sintering of the barium compound, titanium compound, calcium compound, zirconium compound and manganese compound includes: heating from room temperature to 1300°C to 1400°C at a heating rate of 2°C / min to 5°C / min, keeping the temperature for 3h to 5h, and then naturally cooling to room temperature.

[0011] Optionally, the pressure for pressing the pellets is set to 2 MPa to 5 MPa, and the pressing time is set to 60 s to 120 s.

[0012] Optionally, sintering the blank includes a first sintering stage and a second sintering stage.

[0013] Optionally, the sintering temperature of the first sintering stage is 400°C to 600°C; and the sintering temperature of the second sintering stage is 1400°C to 1600°C.

[0014] Optionally, before granulating the powder, the powder needs to be subjected to secondary ball milling and secondary drying.

[0015] Optionally, before performing polarization and aging treatment on the ceramic precursor, the ceramic precursor also needs to be surface treated.

[0016] The present disclosure also provides an application of a barium titanate-based piezoelectric ceramic, wherein the ceramic is applied to any of the following: avionics equipment, collision detection sensors in automobile safety systems, and ultrasound imaging probes in medical equipment.

[0017] The beneficial effects of the present disclosure include:

[0018] (1) Compared with traditional barium titanate-based ceramics, the ceramics provided by the present disclosure have a significantly improved piezoelectric coefficient (540 pC / N), which enables them to produce a larger charge output or mechanical deformation under the same external electric field or mechanical stress, thereby improving the sensitivity and response speed of sensors and actuators;

[0019] (2) Compared with traditional barium titanate-based ceramics, the ceramics provided by the present disclosure have significantly reduced hysteresis (2.8%), which results in low energy loss and high stability during cyclic use. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Various other advantages and benefits of the present disclosure will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The drawings in the specification are intended only to illustrate preferred embodiments and are not to be construed as limiting the present disclosure. Obviously, the drawings described below are merely some embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0021] In the attached figure:

[0022] Figure 1 This is a graph showing the variation of the piezoelectric coefficient and hysteresis of a barium titanate-based piezoelectric ceramic with its composition, provided by one embodiment of the present disclosure;

[0023] Figure 2 This is a schematic flow chart of a method for preparing a barium titanate-based piezoelectric ceramic according to an embodiment of the present disclosure;

[0024] Figure 3 The figure shows the process of measuring the piezoelectric coefficient and hysteresis of the ceramic prepared in Example 1;

[0025] Figure 4 A comparison of the piezoelectric coefficients and hysteresis of the ceramics prepared in Examples 1 to 4 is shown;

[0026] Figure 5 Schematic diagram showing the measurement of the reversible piezoelectric contribution and irreversible piezoelectric contribution of the ceramic prepared in Example 1;

[0027] Figure 6 A graph showing the variation of strain of the ceramic prepared in Example 1 with electric field;

[0028] Figure 7 The piezoelectric contribution composition of each part of the ceramic prepared in Example 1 is shown;

[0029] Figure 8 A comparison chart of the piezoelectric contribution ratios of barium titanate ceramics and ceramics prepared in Examples 1 to 4 is shown. DETAILED DESCRIPTION

[0030] The following will refer to the attached Figures 1 to 8 Specific embodiments of the present disclosure will now be described in greater detail. While specific embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to facilitate a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0031] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present disclosure, but the description is based on the general principles of the specification and is not used to limit the scope of the present disclosure. The scope of protection of the present disclosure shall be as defined by the attached claims.

[0032] In the description of this disclosure, it should be noted that the terms "upper," "lower," "inner," "outer," "front," and "back" and the like, indicating positions or relationships, are based on the operating state of this disclosure and are intended solely for the purpose of facilitating and simplifying the description of this disclosure. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting this disclosure. Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] To facilitate understanding of the embodiments of the present disclosure, further explanation will be given below using specific embodiments as examples in conjunction with the accompanying drawings, and the accompanying drawings do not constitute a limitation on the embodiments of the present disclosure.

[0034] In one exemplary embodiment, the present disclosure provides a barium titanate-based piezoelectric ceramic having the following expression: (1-x)(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-xMn, wherein the value of x is 0.001 to 0.01, preferably 0.002 to 0.005, and more preferably 0.002.

[0035] In this embodiment, by doping a certain amount of Mn (manganese) into the barium titanate matrix, the piezoelectric properties of the material can be effectively adjusted. Specifically, the piezoelectric coefficients and hysteresis of samples with x values of 0, 0.001, 0.002, 0.003, 0.004, 0.005, 0.01, and 0.02 were tested, as shown in Table 1.

[0036] Table 1

[0037] Mn doping amount (x) 0 0.001 0.002 0.003 0.004 0.005 0.01 0.02 <![CDATA[Piezoelectric coefficient (d 33 )(pC / N)]]> 550 548 540 519 494 480 370 299 Hysteresis (%) 10 5.7 2.8 2.8 2.6 2.5 2.5 2.4

[0038] Furthermore, based on Table 1, we can get Figure 1 The performance change curve of barium titanate-based piezoelectric ceramics shown.

[0039] Based on Table 1 and Figure 1 It can be seen that by doping a certain amount of Mn (manganese) into the barium titanate matrix, the piezoelectric coefficient of the ceramic sample gradually decreases with the increase of the Mn doping amount (x). When x≤0.005, the piezoelectric coefficient of the ceramic sample can still maintain a high level (480pC / N to 540pC / N), which is much higher than the piezoelectric coefficient range of traditional barium titanate-based ceramics (usually in the range of 100pC / N to 200pC / N). However, when x=0.02, the piezoelectric coefficient drops significantly to below 300pC / N. In addition, with the increase of the Mn doping amount (x), the hysteresis of the ceramic sample gradually decreases, and when x≥0.002, the hysteresis of the ceramic sample tends to be stable, between 2.5% and 2.8%. This shows that within this doping range, the material has low energy loss and high stability.

[0040] Taking these two key performance indicators into consideration, when the value of x is between 0.001 and 0.01, especially in the range of 0.002 to 0.005, the barium titanate-based ceramic material doped with Mn elements can exhibit significantly improved piezoelectric coefficients (480pC / N to 540pC / N) and lower hysteresis (2.5% to 2.8%). This means that the material is very suitable for applications requiring high voltage electrical response and low energy loss. Within the doping range of 0.002 to 0.005, trace amounts of Mn elements can effectively induce reversible domain wall motion in ceramics. Domain wall motion is one of the key factors affecting the performance of piezoelectric materials. It helps to improve the piezoelectric response efficiency of the material while reducing energy loss or material aging caused by irreversible processes. In particular, when x = 0.002, the piezoelectric coefficient reaches 540pC / N, the hysteresis is reduced to 2.8%, and the contribution of reversible domain wall motion to the total piezoelectric effect reaches a relatively ideal level (domain wall motion is one of the key factors affecting the performance of piezoelectric materials. It helps to improve the piezoelectric response efficiency of the material and reduce energy loss or material aging caused by irreversible processes. Especially when x = 0.002, this optimization makes the movement of the domain wall inside the material highly reversible, further improving the piezoelectric response efficiency).

[0041] In summary, x = 0.002 not only provides the highest piezoelectric coefficient (540pC / N), but also has the lowest hysteresis (2.8%) and performs best in terms of reversible domain wall motion contribution. Based on these characteristics, x = 0.002 is the best choice overall. In contrast, other values either lead to a significant decrease in the piezoelectric coefficient or cannot achieve such a low hysteresis and a high reversible domain wall motion contribution at the same time.

[0042] Furthermore, the selection of x = 0.002 as a superior choice also takes into account the simplicity and reproducibility of the preparation process. At this doping ratio, ceramic materials with stable properties can be obtained through relatively simple solid-phase synthesis methods. This is crucial for large-scale production and practical applications, as a simple and reliable production process ensures consistent product quality and performance, thereby reducing production costs and improving market competitiveness.

[0043] In summary, limiting the value of x to between 0.001 and 0.01, preferably between 0.002 and 0.005, and more preferably to 0.002, is the key to achieving the optimal combination of high efficiency, stability, and ease of large-scale production while ensuring excellent piezoelectric performance. This optimization not only improves the performance of the material itself but also provides a solid foundation for subsequent applications.

[0044] In another exemplary embodiment, Figure 2As shown, the present disclosure also provides a method for preparing barium titanate-based piezoelectric ceramics, the preparation method comprising the following steps:

[0045] S100: Weighing a certain amount of barium compound, titanium compound, calcium compound, zirconium compound, and manganese compound as raw materials for preparing ceramics, and pretreating the raw materials;

[0046] S200: pre-calcining the pretreated barium compound, titanium compound, calcium compound, zirconium compound, and manganese compound to form a powder;

[0047] S300: Granulating the powder to obtain granules;

[0048] S400: pressing the pellets to form blanks;

[0049] S500: sintering the green body to obtain a ceramic precursor;

[0050] S600: performing polarization and aging treatment on the ceramic precursor to obtain barium titanate-based piezoelectric ceramics.

[0051] In another exemplary embodiment, in step S100, the raw material is pre-treated, including the following steps:

[0052] S101: ball milling the raw materials;

[0053] In this step, the amount of balls to be loaded should be determined based on the desired ball milling efficiency to achieve the best mixing uniformity. The weight ratio of balls to materials is 10:1 to 4:1, preferably 8:1 to 4:1, and most preferably 5:1.

[0054] During the ball milling process, appropriate milling media are required to protect the raw materials. In this disclosure, alcoholic solvents are preferred as milling media because they have a low boiling point and are volatile, making them easy to remove during the subsequent drying process. Furthermore, alcoholic solvents have low tension and do not cause the raw materials to agglomerate. Furthermore, this disclosure also prefers the use of anhydrous ethanol, which is non-toxic and safe to handle.

[0055] Furthermore, during the ball milling process, the weight ratio of the raw material to the ball milling media is 2:1 to 1:2, preferably 1:1 to 2:3, and most preferably 1:1. If the ball milling media is too little, the raw material cannot be fully protected. Conversely, if the ball milling media is too much, the ball milling efficiency will be reduced.

[0056] Furthermore, the ball milling speed is set to 200r / min~600r / min, preferably set to 300r / r / min~500r / r / min, and more preferably set to 400r / r / min. During the ball milling process, too high a speed will increase the wear between the ball mill and the grinding balls, thereby introducing impurities and contaminating the sample. The speed within the preferred range (300r / r / min~500r / r / min), especially 400r / min, can effectively reduce this risk, while ensuring the mixing efficiency, reducing the influence of foreign impurities as much as possible. In addition, through experimental verification, it was found that when the ball milling speed is set to 400r / min, it can provide sufficient energy to promote the chemical reaction between the raw materials without destroying the raw materials, while maintaining good dispersibility and particle size, which is crucial for obtaining high-performance piezoelectric ceramics.

[0057] Furthermore, the ball milling time lasts for 5h to 10h, preferably 6h to 9h, and more preferably 8h. The main purpose of ball milling is to ensure that all raw material components (such as barium compounds, titanium compounds, calcium compounds, zirconium compounds and manganese compounds) can be fully and evenly mixed together. Too short a ball milling time (for example, less than 5h) is not enough to achieve an ideal mixing state of the components, which will lead to uneven distribution of components within the material, thereby affecting its piezoelectric properties and other physical properties. As the ball milling time increases, the particles will gradually be refined, but this refinement process is not infinite. Within a certain time range, the particle size will gradually decrease to an optimal value. After exceeding this point, continuing to increase the ball milling time will not only not significantly improve the degree of particle refinement, but may lead to over-crushing and the production of excessive fine powder. These overly fine particles may cause more pores or other defects to form during the sintering process, thereby reducing the density and mechanical strength of the material. Through experimental studies, it was found that within the range of 5h to 10h, the raw materials can achieve good mixing effect and appropriate particle refinement. In the range of 6 to 9 hours, especially 8 hours, the material showed the best uniformity and particle size distribution, while avoiding the above-mentioned problems such as over-crushing and medium volatilization. Therefore, based on the support of experimental data, 8 hours is considered to be the best choice for ball milling time.

[0058] S102: Drying the raw material after ball milling;

[0059] After ball milling, the milled material needs to be dried to remove the milling media from the surface, thereby improving the dispersibility of the powder. The drying temperature is set between 80°C and 130°C, and the drying time is 1 to 3 hours. The optimal drying temperature is 120°C, and the drying time is 1 hour.

[0060] It should be noted that the present disclosure proposes an inventive drying method, which specifically includes the following steps:

[0061] Step 1: Place the ball-milled raw materials in a special microwave transparent container and ensure that the materials are evenly distributed.

[0062] Step 2: Place the container with the raw materials into the microwave vacuum drying equipment, close the door and start the vacuum system to make the chamber reach the predetermined vacuum degree (such as 10 -2 mbar).

[0063] Step 3: Turn on the microwave source and start heating at an appropriate power (adjusted according to the amount of material). Set the heating mode to intermittent pulse mode to optimize the heating effect and prevent local overheating.

[0064] Step 4: After drying is completed, stop the microwave output and slowly restore the normal pressure. Wait until the internal temperature of the equipment drops to a safe value before opening the door to take out the dried raw materials.

[0065] Compared to traditional drying methods, this method can dry the milled raw materials in a shorter time, significantly shortening the production cycle and saving energy. Furthermore, because the drying process is uniform and gentle, it better preserves the original form and activity of the raw materials, reduces particle agglomeration, and facilitates subsequent processing.

[0066] S103: Screening the dried raw materials.

[0067] In this step, the mesh size of the sieve selected for filtration is 60 to 80 meshes, with 60 mesh being the best, in order to improve the density and uniformity during pre-firing. It should be noted that 60-mesh particles have better fluidity during pre-firing and can be filled more tightly, which helps to form a higher density. If the particles are too fine (for example, 80 mesh or finer), although the contact area between the particles can be further increased, it may also cause more gaps between the particles, which is not conducive to densification. In addition, compared with finer sieves, 60-mesh sieves can reduce the loss of effective particles during the screening process. A too fine sieve may screen out some effective particles that were originally suitable for participating in the reaction, resulting in waste of raw materials and affecting the accuracy of the component ratio.

[0068] In another exemplary embodiment, in step S200, the pre-calcining of the pretreated raw materials includes: heating from room temperature to 1300-1400°C at a heating rate of 2-5°C / min, keeping warm for 3h-5h, and then naturally cooling to room temperature; preferably, heating from room temperature to 1300-1350°C at a heating rate of 3-4°C / min, keeping warm for 3h-4h, and then naturally cooling to room temperature; more preferably, heating from room temperature to 1350°C at a heating rate of 3°C / min, keeping warm for 3h, and then naturally cooling to room temperature.

[0069] In this embodiment, heating at a rate of 2 to 5°C / min, and in particular, at a slower rate of 3 to 4°C / min, helps control the phase change process occurring within the material. More particularly, a heating rate of 3°C / min can ensure that the phase change process occurring within the material is well controlled, allowing atoms sufficient time to rearrange, thereby promoting the formation of the desired crystal structure. Compared with a faster heating rate, 3°C / min can reduce stress concentration and crack formation caused by rapid heating. In addition, during high-temperature treatment, rapid temperature changes may cause the sample to crack or deform. Using a slower heating rate (such as 3°C / min) can effectively avoid thermal shock caused by excessive temperature differences and prevent excessive temperature gradients between the sample surface and interior, thereby helping to maintain the integrity of the sample.

[0070] In summary, experimental research has found that, after testing under various conditions, optimal material properties are achieved by heating to 1350°C at a rate of 3°C / min and holding for 3 hours. These conditions ensure the desired physical and chemical changes within the material while minimizing potential negative effects such as cracks and pores.

[0071] It should be noted that before the powder is granulated, it is necessary to perform a secondary ball milling and a secondary drying on the powder. Among them, after the initial ball milling, although the raw materials have been preliminarily mixed and refined, there may still be some larger particles or agglomerates. The secondary ball milling can further refine these particles to ensure that all components are more evenly distributed. Through the secondary ball milling, the contact area between different components is increased, which helps to improve the interface bonding between the phases, thereby improving the overall consistency and stability of the material. In addition, the particle size after the secondary ball milling is reduced, which increases the specific surface area of the material, making the reaction activity between the particles higher in the subsequent sintering process, which is conducive to the formation of a more ideal crystal structure.

[0072] In addition, ball milling media (such as anhydrous ethanol) are usually used during the initial ball milling to protect the raw materials and prevent them from agglomerating. After the secondary ball milling, a certain amount of solvent may remain in the material. Secondary drying can ensure that these residual solvents are completely removed to prevent them from volatilizing and producing gases during subsequent high-temperature treatment, which can lead to the formation of pores or other defects inside the material. Furthermore, fine particles after secondary ball milling are prone to agglomeration. Through secondary drying, the moisture content on the particle surface can be effectively reduced, the interaction force between particles can be reduced, thereby preventing agglomeration and maintaining a good state of particle dispersion.

[0073] It is worth noting that the parameter settings involved in the secondary ball milling and secondary drying are the same as those of the primary ball milling and primary drying.

[0074] It should be noted that the granulation medium used in granulation is a water-soluble polymer, preferably polyvinyl alcohol glue.

[0075] Among them, water-soluble polymers have good adhesion, especially polyvinyl alcohol glue, which helps in the molding and quality control of the final product, and is biodegradable and environmentally friendly.

[0076] The amount of granulating medium added is 5-10 wt% of the powder mass, preferably 6 wt%. In this case, the granulating medium provides sufficient bonding force to enable the powder particles to effectively bond together to form uniform and stable granules.

[0077] Granulation obtains powder with a particle size between 0.15 mm and 0.28 mm.

[0078] After granulation, the obtained powder is preferably dried again at 80° C. to 130° C. for 0.5 h to 2 h, for example, at 120° C. for 1 h, to increase the density and strength of the green piece.

[0079] In another exemplary embodiment, the pressure for pressing the pellets is set to 2 MPa to 5 MPa, preferably 4 MPa; the pressing time is set to 60 s to 120 s, preferably 90 s.

[0080] In this embodiment, a higher pressure helps to expel the air in the powder and arrange the particles more closely, thereby increasing the density of the blank; if the pressure is too high (for example, greater than 5 MPa), it will cause the powder to be over-compacted, causing cracks or damage inside the blank, affecting the structural integrity and performance of the blank. Under a pressure of 2 MPa to 5 MPa, especially at a pressure of 4 MPa, it can ensure that the entire blank is subjected to uniform pressure, which helps to reduce internal defects and stress concentration, and can ensure that the blank has good consistency and mechanical strength. After experiments, it was found that under this pressure, high-quality blanks can be obtained, which not only meets the density requirements of the blank, but also avoids the negative effects caused by excessive compaction. In addition, as time goes on, the structure of the blank gradually stabilizes, which helps to reduce the rebound phenomenon after pressing and maintain the shape and size of the blank. 90 seconds is enough time for the blank structure to stabilize, and at the same time, the production efficiency will not be reduced due to excessive time. 60s to 120s is a reasonable range of production efficiency under the premise of ensuring the quality of the blank. 90s is the optimal choice within this range. It can not only ensure that the blank reaches the required density and stability, but also improve production efficiency to a certain extent and avoid waste of resources caused by unnecessary long-term pressing.

[0081] In another exemplary embodiment, in step S500, sintering the blank includes the following steps:

[0082] S501: heating from room temperature to 400°C to 600°C at a heating rate of 1°C / min to 5°C / min, and keeping the temperature for 4h to 7h;

[0083] S502: Raise the temperature from the holding temperature in step S501 to 1400° C. to 1600° C. at a heating rate of 3° C. / min to 8° C. / min, keep the temperature for 4 h to 6 h, and then cool naturally.

[0084] In this embodiment, during the preparation process, in order to better shape the powder into a blank, some organic matter such as polyvinyl alcohol glue is usually added as a granulation medium. These organic matter needs to be removed at high temperatures, otherwise they will decompose and leave pores or cause cracks during the subsequent high-temperature sintering process. The slower heating rate in the first stage (1°C / min to 5°C / min) helps ensure that these organic matter gradually volatilizes rather than rapidly decomposes and produces a large amount of gas, thereby avoiding defects caused by a sharp increase in internal pressure. In addition, by slowly heating and holding at a certain temperature (for example, 400°C to 600°C), the granulation medium can be fully decomposed and escaped, while allowing the generated gas to have sufficient time to be discharged from the material, which greatly reduces the possibility of pore formation and prevents the occurrence of cracks. The second stage of high-temperature sintering (1400°C to 1600°C) is a key step in forming the final ceramic structure. In this temperature range, diffusion between particles is intensified, grains begin to grow, and the material becomes more dense. This not only improves the mechanical strength of the ceramic, but also improves its electrical and other functional properties. In addition, high-temperature sintering can cause the atoms inside the material to rearrange, forming a more ordered crystal structure, which is crucial for obtaining good piezoelectric properties. In addition, this process can further eliminate any remaining tiny pores and increase the density of the material.

[0085] In summary, the present disclosure utilizes staged control of the sintering process. On the one hand, it can specifically address different types of physical and chemical changes within different temperature ranges, effectively reducing defect rates such as pores and cracks. Furthermore, the two stages optimize debinding and densification, respectively, ensuring the stability and consistency of the blank throughout the sintering process, ultimately improving the quality and performance of barium titanate-based piezoelectric ceramics.

[0086] In a further preferred embodiment,

[0087] In step S501, the temperature is raised from room temperature to 450-550°C at a heating rate of 1°C / min-3°C / min, and kept at this temperature for 4-6 hours;

[0088] In step S502, the temperature is increased from the first stage holding temperature to 1450°C to 1500°C at a heating rate of 3°C / min to 5°C / min, kept at that temperature for 4h to 6h, and then cooled naturally.

[0089] In a further preferred embodiment:

[0090] In step S501, the temperature is raised from room temperature to 500°C at a heating rate of 1°C / min and kept at this temperature for 5 hours;

[0091] In step S502, the temperature is raised from the first stage holding temperature to 1500°C at a heating rate of 5°C / min, kept at that temperature for 6 hours, and then cooled naturally.

[0092] In another exemplary embodiment, before performing polarization and aging treatment on the ceramic precursor, the ceramic precursor needs to be surface treated.

[0093] In this embodiment, the surface treatment of the ceramic precursor includes: first, polishing the surface of the ceramic precursor to a smooth surface (using an appropriate polishing tool, such as sandpaper), to ensure that there are no obvious scratches or unevenness on the surface of the ceramic precursor. Then, the polished ceramic precursor is cleaned, for example, by gently wiping the ceramic surface with anhydrous ethanol or other suitable cleaning solvent to remove any residue.

[0094] It should be noted that surface treatment can remove tiny protrusions or particles on the surface of the ceramic precursor. These structures may cause local overheating during the electrode firing process, leading to the generation of bubbles or cracks. A smooth and flat surface helps to evenly distribute heat and reduce the occurrence of such problems. In addition, a smooth surface is conducive to the application of uniform DC voltage, which makes the electric domain structure inside the ceramic more orderly during the polarization process, which not only improves the piezoelectric coefficient, but also improves the response speed and stability of the material. Furthermore, surface treatment helps to reduce irreversible domain wall motion caused by surface unevenness or impurities, thereby reducing energy loss. Reversible domain wall motion is one of the key factors to improve the efficiency of piezoelectric response, so maintaining high surface quality is very important for obtaining excellent piezoelectric performance.

[0095] In another exemplary embodiment, in step S600, the ceramic precursor is subjected to polarization treatment, including:

[0096] S601: Evenly apply silver paste on the upper and lower surfaces of the sintered and polished ceramic precursor;

[0097] The purpose of this step is to form a conductive layer on the ceramic surface, which serves as an electrode for subsequent application of DC voltage.

[0098] S602: placing the ceramic precursor coated with silver paste into a furnace for electrode firing;

[0099] In this step, the specific parameters of the electrode burning include:

[0100] Heating rate: 3℃ / min~5℃ / min (preferably 5℃ / min)

[0101] Target temperature: 600℃~900℃ (preferably 800℃)

[0102] Insulation time: 20min~60min (preferably 20min)

[0103] Among them, for ceramic precursors coated with silver paste, a slower heating rate helps the solvent in the silver paste to evaporate gradually, avoiding bubbles or cracks caused by rapid volatilization of the solvent due to rapid heating; the temperature of 600℃~900℃ can melt the silver particles and form a continuous conductive network; the holding time is long enough to ensure that the silver particles in the silver paste are fully melted and combined with the surface of the ceramic precursor to form a uniform and dense conductive layer, and 20min~60min is more suitable.

[0104] By firing the electrode, the bonding strength between the silver layer and the surface of the ceramic precursor can be enhanced, thereby ensuring that the formed conductive layer is stable and reliable.

[0105] S603: applying a DC voltage to the upper and lower ends of the ceramic precursor after electrode firing to achieve polarization.

[0106] In this step, a DC voltage of 0.7 kV / mm to 2 kV / mm is applied to the upper and lower ends of the fired ceramic precursor for polarization for 30 to 60 minutes; preferably, a DC voltage of 1 kV / mm is applied for 40 minutes. This polarization treatment can orderly align the electrical domain structure within the ceramic precursor, thereby improving the piezoelectric coefficient and stability of the material.

[0107] It should be noted that within this voltage range, sufficient electric field strength is provided to enable the electric domains within the ceramic material to overcome internal energy barriers and align themselves from random orientation to one aligned with the applied electric field. This is crucial for forming a highly ordered electric domain structure, thereby significantly improving the material's piezoelectric coefficient. However, excessively high voltages can lead to material breakdown, a phenomenon characterized by a sudden increase in current flow, resulting in localized overheating and even structural damage. Therefore, an upper limit (2 kV / mm) is set to mitigate this risk and ensure the safety of the polarization process. A time range of 30 to 60 minutes is sufficient for the electric domains to complete the transition from their initial state to their final stable state. Particularly for samples with complex microstructures or thicker structures, more time is required to ensure effective alignment of the electric domains throughout the entire volume. While longer poling times may result in better performance, considering actual production costs and efficiency, it is important to select a time that ensures good results without excessively increasing production cycle time. A time range of 30 to 60 minutes offers a compromise, ensuring effective polarization without significantly increasing manufacturing costs. Furthermore, experiments have shown that a voltage of 1 kV / mm and a poling time of 40 minutes provide the best piezoelectric performance in most cases. This combination effectively aligns the electric domain structure without damaging the material, while avoiding potential problems caused by unnecessary long-term processing or excessive high voltage.

[0108] In addition, after polarization, the ceramic precursor needs to be further placed at a specific temperature for aging treatment to further release internal stress and make the material structure more stable. This disclosure introduces an aging treatment method, which specifically includes the following steps:

[0109] Step 1: linear temperature increase;

[0110] In this step, the ambient temperature is linearly increased from room temperature to the aging temperature at a rate of 1°C / min to 3°C / min, preferably 1°C / min. Stress relaxation occurs gradually during the heating process to avoid thermal shock and microcrack propagation that may be caused by direct high-temperature treatment. This stage helps activate some reversible defects in the ceramic precursor, preparing for subsequent deeper structural adjustments.

[0111] Step 2: Aging treatment;

[0112] In this step, the aging temperature is set to 40°C to 50°C, preferably 50°C. When the ambient temperature reaches the aging temperature, the temperature is maintained for 0 to 16 days, preferably 14 days, that is, 336 hours. During the continuous heat preservation and aging process, the energy of atomic motion inside the ceramic precursor is effectively improved, promoting the further release of residual stress and the repair of lattice defects. This stage is the core of the entire aging treatment and can effectively improve the microstructural uniformity and stability of the ceramic precursor.

[0113] Step 3: Cooling and tempering;

[0114] In this step, the temperature is slowly lowered from the aging temperature to room temperature at a rate of 0.5°C / hour. The entire cooling process takes approximately 50 hours. This extremely slow cooling process ensures that the internal structure of the ceramic precursor remains stable during the temperature change, reducing the generation of new stresses or the redistribution of existing stresses caused by rapid cooling.

[0115] Step 4: Stabilize at room temperature.

[0116] In this step, the ceramic precursor after cooling and tempering is kept at room temperature for at least 48 hours. By allowing the ceramic precursor to stand for a period of time under conditions close to the use environment, its internal structure can be completely stabilized, ensuring that its physical and chemical properties reach the optimal state for subsequent processing or direct use.

[0117] In summary, the present disclosure utilizes a phased and carefully controlled temperature change to effectively avoid material damage caused by sudden temperature changes while maximizing internal stress release and structural optimization. Compared to traditional rapid cooling methods, the slow cooling strategy employed in this process significantly reduces the risk of new stress formation caused by excessive temperature gradients, thereby ensuring superior overall material performance.

[0118] The present disclosure is further described below through specific examples, but these examples are merely exemplary and do not constitute any limitation to the scope of protection of the present disclosure.

[0119] Example 1

[0120] (1) In this example, the chemical expression is 0.999(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9O3)-0.001Mn, calculated based on the preparation of 20g of finished product, the masses of the required raw materials CaCO3, BaZrO3, BaCO3, TiO2 and MnCO3 are 1.3455g, 2.4784g, 13.264g and 6.4419g respectively. The weighed raw materials are placed in a ball mill, and anhydrous ethanol (the mass ratio of the raw materials to anhydrous ethanol is 1:1) and agate balls (the weight ratio of the balls to the materials is 5:1) are added, and ball milled at 400r / min for 8h; then the ball-milled raw materials are dried at 120℃ for 1h, then put into a mortar and ground, passed through a 60-mesh sieve, and the sieved powder is put into a crucible and compacted, placed on a zirconium plate and placed in a muffle furnace, and pre-sintered from room temperature to 1350℃ at a heating rate of 3℃ / min, kept warm for 3h, and then naturally cooled to room temperature, taken out of the furnace to obtain a powder;

[0121] (2) Grinding the powder into fine powder in a mortar and putting it into a ball mill, adding anhydrous ethanol (the mass ratio of powder to anhydrous ethanol is 1:1) and agate balls (the weight ratio of balls to materials is 5:1), and ball milling for a second time at 400 r / min for 12 hours, and then drying at 120°C for 2 hours; grinding the dried powder in a mortar and adding 6wt% polyvinyl alcohol glue; then sieving through sieves of different apertures to select powder with a particle size of 0.15mm to 0.28mm; then drying the obtained powder again at 120°C for 1 hour, and then pouring it into a stainless steel mold with a diameter of 10mm, and maintaining the pressure at 4MPa for 90 seconds to form a cylindrical blank;

[0122] (3) The blank is placed on a zirconium plate and placed in a muffle furnace, and sintered according to the following procedure to obtain a ceramic precursor:

[0123] The first stage: heating from room temperature to 500°C at a heating rate of 1°C / min and keeping at this temperature for 5h;

[0124] The second stage: heating from the first stage holding temperature to 1500℃ at a heating rate of 5℃ / min, holding for 6h, and then cooling naturally;

[0125] (4) The precursor was polished smooth, silver paste was applied on the upper and lower surfaces, and the precursor was placed in a furnace and heated from room temperature to 800°C at a heating rate of 100°C, kept warm for 20 minutes, and then cooled naturally to complete the electrode burning operation; then a DC voltage of 1 kV / mm was applied to the upper and lower ends of the sample after the electrode burning, and polarized at this voltage for 40 minutes to obtain ceramics.

[0126] Example 2

[0127] (1) In this example, the chemical expression is 0.998(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9O3)-0.002Mn, calculated based on the preparation of 20g of finished product, the masses of the required raw materials CaCO3, BaZrO3, BaCO3, TiO2 and MnCO3 are 1.3441g, 2.476g, 13.2507g and 6.4354g respectively. The weighed raw materials are placed in a ball mill, and anhydrous ethanol (the mass ratio of the raw materials to anhydrous ethanol is 1:1) and agate balls (the weight ratio of the balls to the materials is 5:1) are added, and ball milled at 400r / min for 8h; the ball-milled raw materials are then dried at 120°C for 1h, then ground in a mortar, passed through a 60-mesh sieve, and the sieved powder is placed in a crucible, compacted, placed on a zirconium plate and placed in a muffle furnace, pre-calcined from room temperature to 1350°C at a heating rate of 3°C / min, kept warm for 3h, then naturally cooled to room temperature, taken out of the furnace, and obtained a powder;

[0128] (2) Grinding the powder into a fine powder in a mortar and charging it into a ball mill, adding anhydrous ethanol (at this time, the mass ratio of powder to anhydrous ethanol is 1:1) and agate balls (the weight ratio of balls to materials is 5:1), and ball milling for a second time at 400 r / min for 12 hours, and then drying at 120°C for 12 hours; grinding the dried powder in a mortar and adding 6wt% polyvinyl alcohol glue; then sieving through sieves of different apertures to select powder with a particle size of 0.15mm to 0.28mm; then drying the obtained powder again at 120°C for 1 hour, and then pouring it into a stainless steel mold with a diameter of 10mm, and maintaining the pressure at 4MPa for 90 seconds to form a cylindrical blank;

[0129] (3) The blank is placed on a zirconium plate and placed in a muffle furnace, and sintered according to the following procedure to obtain a ceramic precursor:

[0130] The first stage: heating from room temperature to 500°C at a heating rate of 1°C / min and keeping at this temperature for 5h;

[0131] The second stage: heating from the first stage holding temperature to 1500℃ at a heating rate of 5℃ / min, holding for 6h, and then cooling naturally;

[0132] (4) The precursor was polished smooth, silver paste was applied on the upper and lower surfaces, and the precursor was placed in a furnace and heated from room temperature to 800°C at a heating rate of 5°C / min, kept warm for 20 minutes, and then cooled naturally to complete the electrode burning operation; then a DC voltage of 1 kV / mm was applied to the upper and lower ends of the sample after the electrode burning, and polarized at this voltage for 40 minutes, and then aged at 50°C for 336 hours to obtain ceramics.

[0133] Example 3

[0134] (1) In this embodiment, the chemical expression is 0.995(Ba 0.85 Ca 0.15 Zr 0.1 Ti0.9 O3)-0.005Mn, calculated based on the preparation of 20g of finished product, the masses of the required raw materials CaCO3, BaZrO3, BaCO3, TiO2 and MnCO3 are 1.3401g, 2.4685g, 13.2109g and 6.4161g respectively. The weighed raw materials are placed in a ball mill, and anhydrous ethanol (the mass ratio of the raw materials to anhydrous ethanol is 1:1) and agate balls (the weight ratio of the balls to the materials is 5:1) are added, and ball milled at 400r / min for 8h; the ball-milled raw materials are then dried at 120°C for 1h, then ground in a mortar, passed through a 60-mesh sieve, and the sieved powder is placed in a crucible and compacted, placed on a zirconium plate and placed in a muffle furnace, and pre-fired from room temperature to 1350°C at a heating rate of 3°C / min, kept warm for 3h, then naturally cooled to room temperature, taken out of the furnace, and obtained a powder;

[0135] (2) Grinding the powder into a fine powder in a mortar and charging it into a ball mill, adding anhydrous ethanol (at this time, the mass ratio of powder to anhydrous ethanol is 1:1) and agate balls (the weight ratio of balls to materials is 5:1), and ball milling for a second time at 400 r / min for 12 hours, and then drying at 120°C for 12 hours; grinding the dried powder in a mortar and adding 6wt% polyvinyl alcohol glue; then sieving through sieves of different apertures to select powder with a particle size of 0.15mm to 0.28mm; then drying the obtained powder again at 120°C for 1 hour, and then pouring it into a stainless steel mold with a diameter of 10mm, and maintaining the pressure at 4MPa for 90 seconds to form a cylindrical blank;

[0136] (3) The blank is placed on a zirconium plate and placed in a muffle furnace, and sintered according to the following procedure to obtain a ceramic precursor:

[0137] The first stage: heating from room temperature to 500°C at a heating rate of 1°C / min and keeping at this temperature for 5h;

[0138] The second stage: heating from the first stage holding temperature to 1500℃ at a heating rate of 5℃ / min, holding for 6h, and then cooling naturally;

[0139] (4) The precursor was polished smooth, silver paste was applied on the upper and lower surfaces, and the precursor was placed in a furnace and heated from room temperature to 800°C at a heating rate of 5°C, kept warm for 20 minutes, and then cooled naturally to complete the electrode burning operation; then a DC voltage of 1 kV / mm was applied to the upper and lower ends of the sample after the electrode burning, and polarized at this voltage for 40 minutes, and then aged at 50°C for 336 hours to obtain ceramics.

[0140] Example 4

[0141] (1) In this example, the chemical expression is 0.99(Ba 0.85 Ca 0.15 Zr0.1 Ti 0.9 O3)-0.01Mn, calculated based on the preparation of 20g of finished product, the masses of the required raw materials CaCO3, BaZrO3, BaCO3, TiO2 and MnCO3 are 1.3334g, 2.4561g, 13.1445g and 6.3838g respectively. The weighed raw materials are placed in a ball mill, and anhydrous ethanol (the mass ratio of the raw materials to anhydrous ethanol is 1:1) and agate balls (the weight ratio of the balls to the materials is 5:1) are added, and ball milled at 400r / min for 8h; then the ball-milled raw materials are dried at 120℃ for 1h, then put into a mortar and ground, passed through a 60-mesh sieve, and the sieved powder is put into a crucible and compacted, placed on a zirconium plate and placed in a muffle furnace, and pre-sintered from room temperature to 1350℃ at a heating rate of 3℃ / min, kept warm for 3h, and then naturally cooled to room temperature, taken out of the furnace to obtain a powder;

[0142] (2) Grinding the powder into a fine powder in a mortar and charging it into a ball mill, adding anhydrous ethanol (at this time, the mass ratio of powder to anhydrous ethanol is 1:1) and agate balls (the weight ratio of balls to materials is 5:1), and ball milling for a second time at 400 r / min for 12 hours, and then drying at 120°C for 12 hours; grinding the dried powder in a mortar and adding 6wt% polyvinyl alcohol glue; then sieving through sieves of different apertures to select powder with a particle size of 0.15mm to 0.28mm; then drying the obtained powder again at 120°C for 1 hour, and then pouring it into a stainless steel mold with a diameter of 10mm, and maintaining the pressure at 4MPa for 90 seconds to form a cylindrical blank;

[0143] (3) The blank is placed on a zirconium plate and placed in a muffle furnace, and sintered according to the following procedure to obtain a ceramic precursor:

[0144] The first stage: heating from room temperature to 500°C at a heating rate of 1°C / min and keeping at this temperature for 5h;

[0145] The second stage: heating from the first stage holding temperature to 1500℃ at a heating rate of 5℃ / min, holding for 6h, and then cooling naturally;

[0146] (4) The precursor was polished smooth, silver paste was applied on the upper and lower surfaces, and the precursor was placed in a furnace and heated from room temperature to 800°C at a heating rate of 5°C / min, kept warm for 20 minutes, and then cooled naturally to complete the electrode burning operation; then a DC voltage of 1 kV / mm was applied to the upper and lower ends of the sample after the electrode burning, and polarized at this voltage for 40 minutes, and then aged at 50°C for 72 hours to obtain barium titanate-based piezoelectric ceramics.

[0147] After completing the preparation of ceramics based on the above-mentioned Examples 1 to 4, the present disclosure measures the piezoelectric properties of the ceramics prepared in Examples 1 to 4, respectively. Figure 3The schematic diagram of the piezoelectric coefficient and hysteresis of the ceramics in Example 1 is shown. First, an electric field is applied under a weak field of 0.3kV / cm to 0.8kV / cm to measure the strain of the ceramics, and the piezoelectric coefficient d is obtained accordingly. 33 , Figure 3 The horizontal axis is the electric field intensity (E), the vertical axis is the strain (S), and the ratio of strain to electric field intensity is the piezoelectric coefficient d 33 , expressed as:

[0148]

[0149] Where E0 represents the applied field strength amplitude; S p-p represents the corresponding strain under the electric field E0.

[0150] The hysteresis H is the difference between the upper and lower strains divided by the total strain difference when the electric field is zero. S , expressed as:

[0151]

[0152] Among them, S (0+) and S (0+) They represent the electric field strength of 0 + and the residual strain corresponding to 0-.

[0153] Figure 4 A comparison of the piezoelectric coefficient and hysteresis of the ceramics prepared in Examples 1 to 4 is shown.

[0154] According to the above test results under weak field, the reversible effect (d 33_rev ) and irreversible effects (d 33_irrev ) percentage, such as Figure 4 The schematic diagram of obtaining the reversible piezoelectric contribution and irreversible piezoelectric contribution is shown in Example 1, that is, firstly linearly fitting the piezoelectric coefficient (d 33 ) and electric field strength (E), the fitting line and the vertical axis (d 33 ) is the reversible contribution of the piezoelectric performance (d 33_rev ), the piezoelectric coefficient under a certain electric field strength minus the reversible contribution is the irreversible contribution (d 33_irrev ), expressed as:

[0155] d 33 =d 33_rev +d 33_irrev =d 33_rev +αE

[0156] Where α is the irreversible coefficient.

[0157] Furthermore, the strain of the ceramics was tested under a strong field (20 kV / cm) as a function of the electric field. Figure 6The graph of the variation of strain of the ceramic obtained in Example 1 with the electric field is shown. The slope of the linear region in the graph is the intrinsic lattice contribution of the piezoelectric performance (d 33_rev_latt ),Right now (Saturation section).

[0158] Furthermore, the piezoelectric performance can be divided into the reversible contribution that does not produce hysteresis (d 33_rev ) and the irreversible contribution to hysteresis (d 33_irrev ), can also be divided into the intrinsic contribution caused by lattice expansion and the extrinsic contribution caused by domain wall motion according to the mechanism of action. Therefore, the intersection of the reversible contribution and the extrinsic contribution is the reversible extrinsic contribution caused by reversible domain wall motion (d 33_rev_dw ), Figure 7 The piezoelectric contribution of each part of the ceramic is shown in Example 1. Figure 6 The irreversible domain wall motion is calculated by the method listed. Figure 5 The reversible domain wall motion is calculated by the method listed above as the reversible piezoelectric contribution minus the lattice stretching contribution. Figure 8 A comparison chart of the piezoelectric contribution ratios of barium titanate ceramics (BT) and ceramics prepared in Examples 1 to 4 is shown.

[0159] The voltage coefficient, hysteresis and contribution ratio of reversible domain wall motion of the ceramics prepared in Examples 1 to 4 are summarized, and the results are shown in Table 2:

[0160] Table 2

[0161]

[0162] Combine Figure 4 、 Figure 8 As can be seen from Table 2, the piezoelectric coefficients of all embodiments are significantly higher than those of traditional barium titanate-based ceramics (usually in the range of 100pC / N to 200pC / N). Among them, Example 1 has the highest piezoelectric coefficient (548pC / N), but its hysteresis is relatively high. In addition, Example 2 has the lowest hysteresis (2.8%), which indicates that it can maintain high stability and efficiency during cyclic use. In addition, Example 2 performs best in terms of the contribution of reversible domain wall motion, reaching 64%, showing excellent non-intrinsic contribution characteristics.

[0163] In summary, combining the three key performance indicators above, Example 2 proved to be the optimal choice, as it not only possessed a near-highest piezoelectric coefficient (540pC / N), but also had the lowest hysteresis (2.8%) and the highest contribution from reversible domain wall motion (64%). These properties make the material of Example 2 well-suited for applications requiring high-voltage electrical response and low energy loss, such as high-performance sensors and actuators.

[0164] In another exemplary embodiment, the present disclosure further provides an application of a barium titanate-based piezoelectric ceramic, wherein the ceramic is applied to any of the following: avionics equipment, collision detection sensors in automobile safety systems, and ultrasound imaging probes in medical equipment.

[0165] In this embodiment, the ceramic provided by the present disclosure has a significantly improved piezoelectric coefficient (370pC / N to 550pC / N), which is much higher than that of traditional barium titanate-based ceramics. This means that under the same external electric field or mechanical stress, the ceramic can produce a larger charge output or mechanical deformation, thereby improving the sensitivity and response speed of sensors and actuators. In addition, the ceramic exhibits a higher contribution of reversible domain wall motion (for example, 64% in Example 2). Domain wall motion is one of the key factors affecting the performance of piezoelectric materials. It helps to improve the piezoelectric response efficiency of the material and reduce energy loss or material aging caused by irreversible processes. This is particularly important for applications that require frequent operation and are sensitive to response time.

[0166] The present disclosure has been described in detail above with reference to preferred embodiments and exemplary examples. However, it should be noted that these specific embodiments are merely illustrative explanations of the present disclosure and do not constitute any limitation on the scope of protection of the present disclosure. Without departing from the spirit and scope of protection of the present disclosure, various improvements, equivalent substitutions, or modifications may be made to the technical content and embodiments of the present disclosure, all of which fall within the scope of protection of the present disclosure. The scope of protection of the present disclosure shall be subject to the appended claims.

Claims

1. A barium titanate-based piezoelectric ceramic, characterized in that: The ceramic has the following expression: (1-x)(No 0.85 Ca 0.15 Zr 0.1 You 0.9 O3)-xMn, in, The value of x is: 0.001~0.

01.

2. A method for preparing barium titanate-based piezoelectric ceramics, characterized in that: Preferably, the method comprises: Pretreatment of barium compounds, titanium compounds, calcium compounds, zirconium compounds and manganese compounds; pre-calcining the pretreated barium compound, titanium compound, calcium compound, zirconium compound and manganese compound to form a powder; granulating the powder to obtain granules; pressing the pellets to form blanks; sintering the green body to obtain a ceramic precursor; The ceramic precursor is subjected to polarization and aging treatment to obtain barium titanate-based piezoelectric ceramics.

3. The method according to claim 2, characterized in that Pretreatment of barium, titanium, calcium, zirconium and manganese compounds, including: ball milling the barium compound, titanium compound, calcium compound, zirconium compound and manganese compound; drying the barium compound, titanium compound, calcium compound, zirconium compound and manganese compound after ball milling; The dried barium compound, titanium compound, calcium compound, zirconium compound and manganese compound are sieved.

4. The method according to claim 2, characterized in that The pre-calcining of the barium compound, titanium compound, calcium compound, zirconium compound and manganese compound comprises: The temperature was raised from room temperature to 1300°C to 1400°C at a heating rate of 2°C / min to 5°C / min, and kept at this temperature for 3h to 5h, and then naturally cooled to room temperature.

5. The method according to claim 3, characterized in that The pressure for pressing the pellets is set to 2 MPa to 5 MPa, and the pressing time is set to 60 s to 120 s.

6. The method according to claim 3, characterized in that Sintering the green body includes a first sintering stage and a second sintering stage.

7. The method according to claim 6, characterized in that The sintering temperature of the first sintering stage is 400°C to 600°C; the sintering temperature of the second sintering stage is 1400°C to 1600°C.

8. The method according to claim 3, characterized in that Before the powder is granulated, the powder needs to be subjected to secondary ball milling and secondary drying.

9. The method according to claim 3, characterized in that Before performing polarization and aging treatment on the ceramic precursor, the ceramic precursor also needs to be surface treated.

10. An application of a barium titanate-based piezoelectric ceramic, characterized in that: The barium titanate-based piezoelectric ceramic is applied to any of the following: avionics equipment, collision detection sensors in automobile safety systems, and ultrasound imaging probes in medical equipment.

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