A composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic and its preparation method

Abstract

This invention relates to the field of piezoelectric ceramics technology, and in particular to a composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic and its preparation method. The general formula for high-temperature piezoelectric ceramics is: Ca 1‑x (LiCe) x / 2 Bi 3.75 Nd 0.25 Ti 3.935 Sc 0.065 O 15 , where x is a complex high-valence ion (LiCe). 4+ Twice the molar amount, x = 0.02, 0.05, 0.08, 0.10. This invention employs the above-mentioned composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic and its preparation method to meet the application requirements in high-temperature environments while ensuring the material's environmental friendliness.

Description

Technical Field

[0001] This invention relates to the field of piezoelectric ceramics technology, and in particular to a composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic and its preparation method. Background Technology

[0002] Piezoelectric ceramics are a class of functional materials exhibiting the piezoelectric effect. The piezoelectric effect refers to the phenomenon where certain dielectric materials generate electrical charges on their surface due to internal polarization when deformed under mechanical stress. Piezoelectric devices developed based on this property, such as sensors, transducers, transformers, and resonators, have been widely used in numerous fields, including electronic equipment, the automotive industry, and aerospace.

[0003] In the current piezoelectric ceramic materials market, lead zirconate titanate (PZT) dominates due to its mature commercialization. Typical commercial PZT materials mostly have compositions near the quasi-isomorphic phase boundary (MPB), and their Curie temperature (T) is... C The temperature range is between 150-380℃. Due to the limited operating temperature of piezoelectric devices, the maximum operating temperature typically does not exceed T. C / 2 (long-term stable work) or 3T C The 4 / 4 (short-term operation) characteristic limits the operating temperature of PZT-based devices to below 200°C. However, in specialized fields such as aerospace, nuclear energy, chemical engineering, and geothermal energy, equipment often requires vibration signal monitoring in high-temperature environments above 500°C. This necessitates that the relevant sensors not only maintain high sensitivity but also possess excellent performance stability under high-temperature conditions. Therefore, high-temperature piezoelectric sensors have become a key research focus.

[0004] Bismuth layered piezoelectric ceramics (BLSFs) exhibit excellent high-temperature stability due to their unique crystal structure, with Curie temperatures generally exceeding 500℃. These ceramics consist of a bismuth-oxygen layer (Bi₂O₂). 2+ and pseudo-perovskite layer (A) m-1 B m O 3m+1 ) 2- The perovskite layers are formed by alternating arrangements along the c-axis, where m is the number of (BO6) octahedra arranged along the c-axis in the unit cell, i.e., the number of perovskite layers. Currently, research mainly focuses on m=2 (e.g., CaBi2Nb2O9) and m=3 (e.g., Bi4Ti3O) layers. 12 ) and m=4 (e.g., CaBi4Ti4O) 15 The CBT system. However, bismuth layered piezoelectric ceramics also have limitations. Their spontaneous polarization vector is confined to the ab plane, resulting in generally low piezoelectric activity.

[0005] Taking CBT as an example, it has an orthorhombic crystal structure and a Curie temperature as high as 780℃, but its piezoelectric coefficient (d) is low. 33 Its piezoelectric activity is only about 8 pC / N. To improve its performance, researchers have conducted extensive modification studies, mainly including A-site equivalent composite ion substitution, such as (LiCe), (NaCe), and (LiHo), as well as B-site donor doping. Nevertheless, its low piezoelectric activity still restricts the application and development of bismuth layered piezoelectric ceramics. Therefore, it is urgent to further explore the doping characteristics of this type of material and develop CBT piezoelectric materials with excellent comprehensive performance. Summary of the Invention

[0006] The purpose of this invention is to provide a composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic and its preparation method, so as to meet the application requirements in high-temperature environments and ensure that the material is environmentally friendly.

[0007] To achieve the above objectives, this invention provides a composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic, the general formula of which is: Ca 1-x (LiCe) x / 2 Bi 3.75 Nd 0.25 Ti 3.935 Sc 0.065 O 15 , where x is a complex high-valence ion (LiCe). 4+ Twice the molar amount, x = 0.02, 0.05, 0.08, 0.10.

[0008] Preferably, the piezoelectric coefficient of the high-temperature piezoelectric ceramic is 18-22 pC / N, and the Curie temperature is 770-783℃.

[0009] The preparation method of the above-mentioned composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic includes the following steps:

[0010] S1. Weigh analytical grade calcium carbonate, lithium carbonate, cerium oxide, bismuth oxide, neodymium trioxide, titanium dioxide, and scandium oxide according to the general stoichiometric ratio of high temperature piezoelectric ceramics, add them to a ball mill jar, and use anhydrous ethanol as the ball milling medium for rolling ball milling. After drying, a mixed powder is obtained.

[0011] S2. The mixed powder of S1 is pre-fired at 850℃ for 4 hours to obtain ceramic pre-fired powder;

[0012] S3. Place the pre-fired ceramic powder from S2 back into the ball mill jar, add anhydrous ethanol, seal the ball mill jar, and ball mill for 24 hours. Then dry the powder to obtain dry pre-fired ceramic powder.

[0013] S4. Add polyvinyl alcohol aqueous solution to the pre-fired ceramic powder dried in S3, and granulate and sieve in sequence to obtain the powder required for pressing.

[0014] S5. Press the powder required for pressing in S4 into discs under a pressure of 10MPa, and after debinding at high temperature, obtain ceramic blanks.

[0015] S6. Sinter the ceramic blank at 1080~1280℃ for 4-8 hours to obtain the piezoelectric ceramic body;

[0016] S7. After polishing, the S6 piezoelectric ceramic body is coated with a silver electrode and polarized by applying a voltage to prepare a material with the general chemical formula Ca. 1-x (LiCe) x / 2 Bi 3.75 Nd 0.25 Ti 3.935 Sc 0.065 O 15 High-temperature piezoelectric ceramics.

[0017] Preferably, in S1, during the rolling ball milling process, the grinding jar is a nylon jar and the grinding balls are zirconium balls.

[0018] Preferably, in S2, pre-firing involves placing the mixed powder in a corundum crucible and heating it.

[0019] Preferably, in S4, the mass percentage of the polyvinyl alcohol aqueous solution is 8-10 wt%, and the granulated powder is sieved using a 60-mesh sieve.

[0020] Preferably, in S7, after the piezoelectric ceramic body is coated with a silver electrode, it is placed in high-temperature silicone oil for polarization. The polarization temperature is constant at 180-220℃, the polarization electric field strength is a DC electric field of 8-20kV / cm, and the polarization time is 30min.

[0021] The beneficial effects of this invention are:

[0022] (1) This invention employs the above-mentioned composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic and its preparation method. The resulting piezoelectric ceramic material exhibits a high Curie temperature (Ti). C =770-783℃) and improved piezoelectric properties (d 33 =18-22 pC / N). It can operate stably in high-temperature environments and is suitable for aerospace, nuclear energy and other fields. Moreover, this piezoelectric ceramic material does not contain lead and is an environmentally friendly material.

[0023] (2) The present invention uses the above-mentioned composite ion modified bismuth layered bismuth titanate calcium-based high temperature piezoelectric ceramic and its preparation method. The process is simple and stable, easy to operate, and convenient for industrial production.

[0024] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0025] Figure 1 This is a schematic flowchart of the preparation method in Embodiment 1 of the present invention;

[0026] Figure 2 X-ray diffraction (XRD) patterns of the high-temperature piezoelectric ceramics prepared in Examples 1-4;

[0027] Figure 3 This is a schematic diagram showing the change of dielectric constant of the high-temperature piezoelectric ceramics prepared in Examples 1-4 of the present invention with temperature (50-800℃); Figure 3 (a) in the figure is a schematic diagram showing the change of dielectric constant of the high-temperature piezoelectric ceramic in Example 1 with temperature. Figure 3 (b) in the figure is a schematic diagram showing the change of dielectric constant of the high-temperature piezoelectric ceramic in Example 2 with temperature. Figure 3 (c) in the figure is a schematic diagram showing the change of dielectric constant of the high-temperature piezoelectric ceramic in Example 3 with temperature. Figure 3 (d) in the figure is a schematic diagram of the dielectric constant of the high-temperature piezoelectric ceramic of Example 3 as a function of temperature;

[0028] Figure 4 This is a schematic diagram showing the change in resistivity of the high-temperature piezoelectric ceramics prepared in Examples 1-4 of the present invention with temperature (200-600℃). Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0030] This invention provides a composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic, the general formula of which is: Ca 1-x (LiCe) x / 2 Bi 3.75 Nd 0.25 Ti 3.935 Sc 0.065 O 15 , where x is a complex high-valence ion (LiCe). 4+ Twice the molar amount, x = 0.02, 0.05, 0.08, 0.10.

[0031] In this invention, (LiCe) is incorporated into bismuth calcium titanate ceramic. 4+ 、Nd 3+ and Sc 3+ (LiCe) 4+ and Nd3+ Perform A-position substitution, Sc 3+ B-site substitution causes lattice distortion, thereby adjusting the crystal structure and improving the piezoelectric properties of the ceramic system. Since the ion radius at the B site is smaller than that at the A site, the degree of lattice distortion caused by B-site doping is smaller, and the performance improvement is not as significant as with A-site doping. Therefore, this invention chooses to further adjust the (LiCe) at the A site. 4+ The molar percentage of composite ions can be used to deeply adjust the lattice structure, reduce the oxygen vacancy concentration caused by Bi volatilization, and promote ferroelectric domain flipping, thereby simultaneously improving piezoelectric properties and Curie temperature.

[0032] In some specific embodiments of the present invention, the Nd of high-temperature piezoelectric ceramics... 3+ The molar percentage is 0.25, Sc 3+ The molar percentage is 0.065. When this ratio is deviated from, the lattice and domain structure will change, affecting the domain flipping characteristics and thus the macroscopic performance. When the molar ratio of all ions in the general formula deviates drastically from this ratio, excess elements are prone to form impurity phases during the doping process, hindering domain flipping and leading to a decrease in piezoelectric performance.

[0033] Preferably, the piezoelectric coefficient of the high-temperature piezoelectric ceramic is 18-22 pC / N, and the Curie temperature is 770-783℃.

[0034] The high-temperature piezoelectric ceramic material of the present invention exhibits excellent piezoelectric constant and high Curie temperature, and is suitable for key fields such as aerospace, nuclear energy, chemical industry, and geothermal energy.

[0035] The preparation method of the above-mentioned composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic includes the following steps:

[0036] S1. Weigh analytical grade calcium carbonate, lithium carbonate, cerium oxide, bismuth oxide, neodymium trioxide, titanium dioxide, and scandium oxide according to the general stoichiometric ratio of high temperature piezoelectric ceramics, add them to a ball mill jar, and use anhydrous ethanol as the ball milling medium for rolling ball milling. After drying, a mixed powder is obtained.

[0037] S2. The mixed powder of S1 is pre-fired at 850℃ for 4 hours to obtain ceramic pre-fired powder;

[0038] S3. Place the pre-fired ceramic powder back into the ball mill jar, add anhydrous ethanol, seal the ball mill jar, and ball mill for 24 hours. Then dry the powder to obtain dry pre-fired ceramic powder.

[0039] S4. Add polyvinyl alcohol aqueous solution to the pre-fired ceramic powder dried in S3, and granulate and sieve in sequence to obtain the powder required for pressing.

[0040] S5. Press the powder required for pressing in S4 into discs under a pressure of 10MPa, and after debinding at high temperature, obtain ceramic blanks.

[0041] S6. Sinter the ceramic blank at 1080~1280℃ for 4-8 hours to obtain the piezoelectric ceramic body;

[0042] S7. After polishing, the S6 piezoelectric ceramic body is coated with a silver electrode and polarized by applying a voltage to prepare a material with the general chemical formula Ca. 1-x (LiCe) x / 2 Bi 3.75 Nd 0.25 Ti 3.935 Sc 0.065 O 15 High-temperature piezoelectric ceramics.

[0043] Preferably, in S1, during the rolling ball milling process, the grinding jar is a nylon jar and the grinding balls are zirconium balls.

[0044] Preferably, in S2, pre-firing involves placing the mixed powder in a corundum crucible and heating it.

[0045] Preferably, in step S4, the mass percentage of the polyvinyl alcohol aqueous solution is 8-10 wt%, and the granulated powder is sieved using a 60-mesh sieve. If the added polyvinyl alcohol aqueous solution is less than 8 wt%, the sample is likely to be misshapen, making it impossible to obtain piezoelectric ceramic material. If it is more than 10 wt%, the piezoelectric performance is likely to be reduced or the sample may contain pores, resulting in the inability to obtain dense piezoelectric ceramic material.

[0046] In some specific embodiments of the present invention, the polyvinyl alcohol aqueous solution has a mass percentage of 8 wt%.

[0047] In some specific embodiments of the present invention, in S6, the sintering temperature and time are as follows: when x = 0.02, the sintering temperature is 1080°C and the time is 4 hours; when x = 0.05, the sintering temperature is 1150°C and the time is 4 hours; when x = 0.08, the sintering temperature is 1200°C and the time is 6 hours; when x = 0.10, the sintering temperature is 1280°C and the time is 8 hours.

[0048] Preferably, in S7, after the piezoelectric ceramic body is coated with a silver electrode, it is placed in high-temperature silicone oil for polarization. The polarization temperature is constant at 180-220℃, the polarization electric field strength is a DC electric field of 8-20kV / cm, and the polarization time is 30min.

[0049] In some specific embodiments of the present invention, the piezoelectric ceramic body is placed on a polishing machine to polish its surface until both sides are polished to a thickness of 0.5 mm, and then a silver electrode is applied.

[0050] Example 1

[0051] This invention provides a composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic, wherein x = 0.02 in the general formula of the high-temperature piezoelectric ceramic, specifically Ca... 0.98 (LiCe) 0.01 Bi 3.75 Nd 0.25 Ti 3.935 Sc 0.065 O 15 .like Figure 1 As shown, its preparation method includes the following steps:

[0052] S1. Weigh analytically pure calcium carbonate (CaCO3), lithium carbonate (Li2CO3), cerium oxide (CeO2), bismuth oxide (Bi2O3), neodymium trioxide (Nd2O3), titanium dioxide (TiO2), and scandium oxide (Sc2O3) according to the above general formula stoichiometric ratio, add them to a nylon ball mill jar, use anhydrous ethanol as the ball milling medium, and use zirconium balls for rolling ball milling. After ball milling, dry to obtain mixed powder.

[0053] S2. The mixed powder from S1 is placed in an alumina crucible and heated to 850°C for 4 hours to obtain pre-fired ceramic powder.

[0054] S3. Remove the pre-fired ceramic powder from the corundum crucible in S2 and place it back into the ball mill jar. Add anhydrous ethanol, seal the ball mill jar, and ball mill for 24 hours. Then, dry the powder to obtain dry pre-fired ceramic powder.

[0055] S4. Add 8 wt% polyvinyl alcohol aqueous solution to the pre-fired ceramic powder dried in S3 and granulate it sequentially. Use a 60-mesh sieve to screen the granulated powder to obtain powder with uniform particle size for pressing.

[0056] S5. Using an electric tablet press, the powder required for pressing S4 is pressed into round discs under a pressure of 10MPa. After debinding at high temperature, a ceramic blank is obtained.

[0057] S6. Sinter the ceramic blank at 1080℃ for 4 hours to obtain a piezoelectric ceramic body.

[0058] S7. After polishing the S6 piezoelectric ceramic body, a silver electrode is attached, and a voltage is applied for polarization. The ceramic body is then placed in high-temperature silicone oil for polarization. The polarization temperature is kept constant at 180℃, the polarization electric field strength is a DC electric field of 20kV / cm, and the polarization time is 30min, thus obtaining a high-temperature piezoelectric ceramic.

[0059] Example 2

[0060] This invention provides a composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic, wherein x = 0.05 in the general formula of the high-temperature piezoelectric ceramic, specifically Ca...0.95 (LiCe) 0.025 Bi 3.75 Nd 0.25 Ti 3.935 Sc 0.065 O 15 The preparation method is based on Example 1, except that the molar ratio of each raw material in S1 is weighed according to the general formula in Example 2, and in S6, sintering is carried out at 1150°C for 4 hours.

[0061] Example 3

[0062] This invention provides a composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic, wherein x = 0.08 in the general formula of the high-temperature piezoelectric ceramic, specifically Ca 0.92 (LiCe) 0.04 Bi 3.75 Nd 0.25 Ti 3.935 Sc 0.065 O 15 The preparation method is based on Example 1, except that the molar ratio of each raw material in S1 is weighed according to the general formula in Example 3, and in S6, sintering is carried out at 1200°C for 6 hours.

[0063] Example 4

[0064] This invention provides a composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic, wherein x = 0.10 in the general formula of the high-temperature piezoelectric ceramic, specifically Ca 0.90 (LiCe) 0.05 Bi 3.75 Nd 0.25 Ti 3.935 Sc 0.065 O 15 The preparation method is based on Example 1, except that the molar ratio of each raw material in S1 is weighed according to the general formula in Example 3, and in S6, sintering is carried out at 1280°C for 8 hours.

[0065] After the high-temperature piezoelectric ceramics prepared in Examples 1-4 were left to stand in air for 24 hours, their electrical performance was tested using the IEEE standard. The test results are shown in Table 1.

[0066] Table 1. Piezoelectric constants and Curie temperatures of the high-temperature piezoelectric ceramics in Examples 1-4

[0067] Example x Sintering conditions <![CDATA[d 33 (pC / N)]]> <![CDATA[T C (℃)]]> Example 1 0.02 Sintering at 1080℃ for 4 hours 18 770 Example 2 0.05 Sintering at 1150℃ for 4 hours 20 774 Example 3 0.08 Sintering at 1200℃ for 6 hours 22 771 Example 4 0.10 Sintering at 1280℃ for 8 hours 19 783

[0068] As shown in Table 1, within the range of x = 0.02 to x = 0.08, the piezoelectric coefficient d33 increases with the increase of x value, from 18 pC / N to 22 pC / N. When x = 0.10, the piezoelectric coefficient decreases to 19 pC / N. This indicates that (LiCe) 4+ The doping amount of the composite ion has a significant impact on the piezoelectric coefficient. The Curie temperature fluctuates between 770-783℃, reaching a maximum of 783℃ when x = 0.10, indicating that appropriately increasing the doping amount of (LiCe) is beneficial. 4+ The amount of composite ion doping helps to increase the Curie temperature.

[0069] Figure 2 The X-ray diffraction (XRD) patterns of the high-temperature piezoelectric ceramics prepared in Examples 1-4 are shown below. Figure 2 As shown, the XRD patterns of Examples 1-4 all exhibit a single orthorhombic crystal structure, with no impurity phase diffraction peaks, displaying typical diffraction characteristics of a bismuth layered structure, indicating that (LiCe) 4+ All composite ions entered the CBT lattice to form a solid solution without causing the formation of impurity phases. Furthermore, all exhibited distinct diffraction peaks at m=4d within the bismuth layered structure, indicating that they retain the crystallographic characteristics of the bismuth layered structure, i.e., composed of bismuth-oxygen layers (Bi₂O₂). 2+ The fact that the alternating arrangement of the pseudo-perovskite layers along the c-axis was not disrupted indicates that the high-temperature piezoelectric ceramic structure prepared by this invention is stable.

[0070] Figure 3 This is a schematic diagram showing the change of dielectric constant of the high-temperature piezoelectric ceramics prepared in Examples 1-4 of the present invention with temperature (50-800℃), as shown below. Figure 3 As shown, the dielectric constant curves of the high-temperature piezoelectric ceramics prepared in Examples 1-4 all exhibit obvious dielectric peaks in the range of 770-783℃. These peaks correspond to the phase transition temperature of the ferroelectric phase to the paraelectric phase, i.e., the Curie temperature, indicating that (LiCe) 4+ Composite ion doping does not significantly reduce the high-temperature stability of the material, and the Curie temperature remains above 770℃, meeting the application requirements of high-temperature environments above 500℃, and is suitable for high-temperature piezoelectric fields.

[0071] Figure 4 This is a schematic diagram illustrating the change in resistivity of the high-temperature piezoelectric ceramics prepared in Examples 1-4 of this invention as a function of temperature (200-600℃), as shown below. Figure 4 As shown, the resistivity of the high-temperature piezoelectric ceramics prepared in Examples 1-4 gradually decreases with increasing temperature. In the low-temperature range (T < 300℃), the resistivity first increases and then decreases with increasing dopant ion concentration, while in the high-temperature range (T > 300℃), the resistivity increases with increasing dopant ion concentration. This indicates that the high-temperature piezoelectric ceramics prepared by this invention possess good insulation properties in the 200-600℃ range, and the resistivity can be controlled by (LiCe). 4+The doping concentration can be adjusted to make it suitable for high-temperature piezoelectric applications.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic, characterized in that: The general formula for high-temperature piezoelectric ceramics is: Ca 1-x (LiCe) x / 2 Bi 3.75 Nd 0.25 Ti 3.935 Sc 0.065 O 15 , where x is a complex high-valence ion (LiCe). 4+ Twice the molar amount, x = 0.02, 0.05, 0.08, 0.10; The piezoelectric coefficient of high-temperature piezoelectric ceramics is 18-22 pC / N, and the Curie temperature is 770-783℃.

2. A method for preparing the composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic as described in claim 1, characterized in that, Includes the following steps: S1. Weigh analytical grade calcium carbonate, lithium carbonate, cerium oxide, bismuth oxide, neodymium trioxide, titanium dioxide, and scandium oxide according to the general stoichiometric ratio of high temperature piezoelectric ceramics, add them to a ball mill jar, and use anhydrous ethanol as the ball milling medium for rolling ball milling. After drying, a mixed powder is obtained. S2. The mixed powder of S1 is pre-fired at 850℃ for 4 hours to obtain ceramic pre-fired powder; S3. Place the pre-fired ceramic powder from S2 back into the ball mill jar, add anhydrous ethanol, seal the ball mill jar, and ball mill for 24 hours. Then dry the powder to obtain dry pre-fired ceramic powder. S4. Add polyvinyl alcohol aqueous solution to the pre-fired ceramic powder dried in S3, and granulate and sieve in sequence to obtain the powder required for pressing. S5. Press the powder required for pressing in S4 into discs under a pressure of 10MPa, and after debinding at high temperature, obtain ceramic blanks. S6. Sinter the ceramic blank at 1080~1280℃ for 4-8 hours to obtain a piezoelectric ceramic body; S7. After polishing, the S6 piezoelectric ceramic body is coated with a silver electrode and polarized by applying a voltage to prepare a material with the general chemical formula Ca. 1-x (LiCe) x / 2 Bi 3.75 Nd 0.25 Ti 3.935 Sc 0.065 O 15 High-temperature piezoelectric ceramics.

3. The method for preparing composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramics according to claim 2, characterized in that: In S1, during the rolling ball milling process, the grinding jar is a nylon jar and the grinding balls are zirconium balls.

4. The method for preparing composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramics according to claim 2, characterized in that: In S2, pre-firing involves placing the mixed powder in a corundum crucible and heating it.

5. The method for preparing composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramics according to claim 2, characterized in that: In S4, the mass percentage of the polyvinyl alcohol aqueous solution is 8-10 wt%, and the granulated powder is sieved using a 60-mesh sieve.

6. The method for preparing composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramics according to claim 2, characterized in that: In S7, the piezoelectric ceramic body is placed in high-temperature silicone oil after being coated with silver electrodes for polarization. The polarization temperature is constant at 180~220℃, the polarization electric field strength is a DC electric field of 8~20kV / cm, and the polarization time is 30min.

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