Sb < 3 + > / Ta < 5 + > co-doped bismuth titanate-based piezoelectric ceramic as well as preparation method and application thereof

Abstract

The invention provides Sb < 3 + > / Ta < 5 + > co-doped bismuth titanate-based piezoelectric ceramic. The chemical formula of the piezoelectric ceramic is Bi4Ti < 3-2x > (SbTa) xO12, wherein x is not less than 0.01 and not more than 0.03. According to the Sb < 3 + > / Ta < 5 + > co-doping regulation and control method provided by the invention, by increasing lattice distortion and reducing oxygen vacancy concentration, the electrical property of the material is improved while the relative stability and high density of the material structure are ensured. The result shows that the Sb < 3 + > / Ta < 5 + > co-doping not only can obviously improve the piezoelectric coefficient of the BIT ceramic to 25.1 pC / N, but also can ensure that the BIT ceramic still has excellent resistivity of 8.1 * 10 < 6 > omega.cm at 500 DEG C. The invention also provides a preparation method and application of the Sb < 3 + > / Ta < 5 + > co-doped bismuth titanate-based piezoelectric ceramic.

Description

Technical Field

[0001] This invention belongs to the field of functional ceramics, specifically relating to Sb 3+ / Ta 5+ Co-doped bismuth titanate-based piezoelectric ceramics, their preparation methods, and applications. Background Technology

[0002] High Curie temperature bismuth layer-structured ferroelectrics (BLSFs) are an important class of functional ceramic materials with a unique layered structure. Among these materials, bismuth titanate (Bi₄Ti₃O₄) is a prime example. 12 Biologically known as BIT (Biologically Spectroradioactive Induction) is an ideal candidate material for developing high-temperature vibration sensors for harsh environments such as aero-engines and nuclear energy fields, thanks to its high Curie temperature (>600 ℃) and excellent ferroelectric stability at high temperatures.

[0003] However, the alternating arrangement of (Bi2O2) in BIT ceramics 2+ Layers and (Bi2Ti3O) 10 ) 2- The layered structure presents significant challenges to its practical applications. One key issue is its relatively low piezoelectric coefficient (d33≈4-7 pC / N), which severely limits its efficiency in energy conversion and sensing applications. Furthermore, BIT ceramics suffer from high coercivity and insufficient resistivity at temperatures above 500 °C, easily leading to excessive leakage current and performance degradation. Intrinsic defects such as oxygen vacancies generated during bismuth oxide volatilization during sintering, as well as the low material density caused by the anisotropic growth of BIT grains, further exacerbate these performance deficiencies.

[0004] To address these issues, chemical doping has been proven to be a feasible strategy for controlling the piezoelectric and electrical properties of BIT ceramics. However, in B-site doped BIT ceramics, achieving a synergistic improvement in both piezoelectric coefficient and high resistivity at high temperatures (≈500℃) remains a core challenge for current research.

[0005] Chen et al. prepared Cr / Ta co-doped Bi4Ti using a solid-state sintering method. 2.97 (Cr 1 / 3 Ta 2 / 3 ) 0.03 O 12 The ceramic has a piezoelectric coefficient of 26 pC / N and a resistivity of 2.8 × 10⁻⁶ at 500 °C. 6 Ω·cm.

[0006] Liang et al. prepared Mn / Ta co-doped Bi₄Ti using a direct reaction method. 2.95 (Mn 1 / 3 Ta2 / 3 ) 0.05 O 12 Ceramics with piezoelectric coefficient and resistivity at 500 ℃ of 31 pC / N and 7.19×10 5 Ω·cm, respectively.

[0007] Although these co-doping strategies improve the piezoelectric activity of BIT-based ceramics, they fail to address the inherent trade-off between piezoelectric performance and resistivity, which limits the stability of the vibration sensor and makes it difficult to achieve continuous and stable signal output. SUMMARY

[0008] A first object of the present application is to provide a Sb 3+ / Ta 5+ co-doped bismuth titanate-based piezoelectric ceramic with high dielectric coefficient at high temperature.

[0009] A second object of the present application is to provide a preparation method of the Sb 3+ / Ta 5+ co-doped bismuth titanate-based piezoelectric ceramic.

[0010] A third object of the present application is to provide an application of the Sb 3+ / Ta 5+ co-doped bismuth titanate-based piezoelectric ceramic.

[0011] The present application is achieved by the following technical solutions: A Sb 3+ / Ta 5+ co-doped bismuth titanate-based piezoelectric ceramic, with a chemical formula of Bi4Ti 3-2x (SbTa) x O 12 ; wherein 0.01≤x≤0.03.

[0012] The d 3+ 33 of the Sb 5+ / Ta 33 co-doped bismuth titanate-based piezoelectric ceramic is 25.1 pC / N.

[0013] The resistivity of the Sb 3+ / Ta 5+ co-doped bismuth titanate-based piezoelectric ceramic at 500 °C is 8.1×10 6 Ω·cm.

[0014] The preparation method of the Sb 3+ / Ta 5+ co-doped bismuth titanate-based piezoelectric ceramic comprises the following steps: According to Bi4Ti 3-2x (SbTa)x O 12 The stoichiometric ratio of the raw materials TiO2, Bi2O3, Ta2O5 and Sb2O3 is weighed, dried and calcined after the first ball milling; The calcined powder is added with a binder after the second ball milling, and the binder is removed and sintered after the die forming, thereby obtaining the product.

[0015] The medium of the first ball milling is ethanol; The medium of the second ball milling is ethanol.

[0016] The temperature of the drying is 60℃.

[0017] The temperature of the calcining is 825℃; The temperature of the sintering is 1050-1140℃.

[0018] The pressure of the die forming is 150MPa.

[0019] The binder is polyvinyl alcohol.

[0020] The Sb 3+ / Ta 5+ Co-doped bismuth titanate-based piezoelectric ceramic is applied to prepare a vibration sensor with a working temperature higher than 500℃.

[0021] Compared with the prior art, the present application has the following beneficial effects: The Sb 3+ / Ta 5+ Co-doping regulation method is proposed in the present application, which can increase the lattice distortion and reduce the oxygen vacancy concentration, thereby improving the electrical properties while ensuring the relative stability of the material structure and high density. The research results show that the Sb 3+ / Ta 5+ Co-doping strategy can not only significantly improve the piezoelectric coefficient of the BIT ceramic to 25.1 pC / N, but also ensure that the BIT ceramic still has an excellent resistivity of 8.1×10 6 Ω·cm at 500℃. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The XRD patterns of the BIT, BITST1, BITST2 and BITST3 ceramic samples are shown. Among them, Figure 1 (a) is the original spectrum, Figure 1 (b) is an enlarged view of the (117) diffraction peak.

[0023] Figure 2 The Rietveld refinement results and lattice constants of the BIT, BITST1, BITST2 and BITST3 ceramic samples are shown. Among them, Figure 2(a) is the BIT Rietveld refinement result, Figure 2 (b) is the BITST1 Rietveld refinement result, Figure 2 (c) is the BITST2 Rietveld refinement result, Figure 2 (d) is the BITST3 Rietveld refinement result, Figure 2 (e) is the lattice constant graph of BIT, BITST1, BITST2, BITST3 ceramic samples.

[0024] Figure 3 The surface morphology of BIT, BITST1, BITST2, BITST3 ceramic samples is shown. Among them, Figure 2 (a) is the surface morphology of BIT ceramic sample; Figure 2 (b) is the surface morphology of BITST1 ceramic sample; Figure 2 (c) is the surface morphology of BITST2 ceramic sample; Figure 2 (d) is the surface morphology of BITST3 ceramic sample.

[0025] Figure 4 The room temperature piezoelectric coefficient value of BIT, BITST1, BITST2, BITST3 ceramic samples and the room temperature piezoelectric coefficient value after different annealing temperature are shown. Among them Figure 4 (a) shows the room temperature piezoelectric coefficient value of BIT, BITST1, BITST2, BITST3 ceramic samples, Figure 4 (a) shows the room temperature piezoelectric coefficient value curve of BIT, BITST1, BITST2, BITST3 ceramic samples.

[0026] Figure 5 The dielectric constant and dielectric loss temperature curve of BIT, BITST1, BITST2, BITST3 ceramic samples is shown, and the test condition is 100 kHz. Among them, Figure 5 (a) is the dielectric constant-temperature curve of BIT ceramic and Sb 3+ / Ta 5+ co-doped ceramic at 100 kHz frequency. Figure 5 (b) is the dielectric loss-temperature curve of BIT ceramic and Sb 3+ / Ta 5+ co-doped ceramic at 100 kHz frequency.

[0027] Figure 6 (a) is the resistivity-temperature curve of BIT, BITST1, BITST2, BITST3 ceramic samples. Figure 6(b) Arrhenius fitting results of high temperature resistivity of BIT, BITST1, BITST2, BITST3 ceramic samples.

[0028] Figure 7 The impedance spectra of BIT, BITST1, BITST2, BITST3 ceramic samples in the range of 400-550 °C are shown. Among them, Figure 7 (a) The impedance spectra of BIT, ceramic samples in the range of 400-550 °C are shown. Figure 7 (b) The impedance spectra of BITST1 ceramic samples in the range of 400-550 °C are shown, Figure 7 (c) The impedance spectra of BITST2 ceramic samples in the range of 400-550 °C are shown, Figure 7 (d) The impedance spectra of BITST3 ceramic samples in the range of 400-550 °C are shown.

[0029] Figure 8 (a) The O1s fine spectrum of BIT ceramic is shown, Figure 8 (b) The O1s fine spectrum of BITST2 ceramic is shown. DETAILED DESCRIPTION

[0030] According to Bi4Ti 3-2x (SbTa) x O 12 The stoichiometric ratio of (x = 0, 0.01, 0.02, 0.03, respectively BIT, BITST1, BITST2, BITST3) raw materials [TiO2(99.99%, Bi2O3(99.99%), Ta2O5(99.99%) and Sb2O3(99.5%)] were weighed. First, all the raw material powders were mixed with ethanol (purity 99.7%) and ball milled for 5 h, and the slurry after ball milling was dried in a 60 °C oven for 12 h, and then calcined at 825 °C for 2.5 h; the calcined powder was ground again under the same conditions for 10 h, and then pressed into a green body with a diameter of 10 mm and a thickness of 0.8 mm under a pressure of 150 MPa with polyvinyl alcohol (PVA) as a binder. After removing the binder by sintering the green body at 600 °C for 150 min, the target ceramic samples were obtained by conventional solid phase sintering at a temperature range of 1050-1140 °C for 3 h.

[0031] Archimedes principle was used to determine the bulk density of the ceramics. XRD patterns were collected using a Rigaku MiniFlex600 X-ray diffractometer (Cu Ka radiation, l = 0.1541 nm, step size 0.02°; Rietveld refinement step size 0.01°). XPS analysis was performed by a Shimadzu AXIS SUPRA+ X-ray photoelectron spectrometer (Al Ka excitation source, calibrated at the C1s peak at 284.8 eV). The surface grain morphology was observed by a Tescan MIRA3 LMH scanning electron microscope (equipped with OneMax20 energy dispersive spectrometer). The ceramic samples were polished to a thickness of 0.3-0.4 mm, both sides were coated with silver paste and sintered at 600 °C to form electrodes. After polarization for 30 min at 2-7 kV, the piezoelectric d 33 piezoelectric coefficient was measured by a ZJ-3AN quasi-static piezoelectric d

[0032] Figure 1 (a) pure bismuth titanate (BIT) and Sb 3+ / Ta 5+ co-doped Bi4Ti 3-2x (SbTa) x O 12 X-ray diffraction patterns of (BITST1, BITST2, BITST3) ceramics. The diffraction peaks of all samples can be indexed to the standard card PDF#72-1019, corresponding to the space group B2cb, and the (117) diffraction peak of all samples shows the highest intensity, which is consistent with the characteristic peak (112m+1) of bismuth layer-structured ferroelectrics (BLSF) materials. In addition, Figure 1 (b) shows that with the increase of Sb 3+ / Ta 5+ doping amount, the (117) diffraction peak shifts to low diffraction angle. This peak shift phenomenon is due to the lattice expansion effect: the doping ion Sb 3+ (coordination number CN = 6, ion radius 0.76 Å) and Ta 5+(When CN=6, the ionic radius is 0.64 Å) replaces the smaller Ti in the lattice. 4+ (Ionic radius 0.605 Å at CN=6). The above XRD analysis results indicate that Sb can be achieved by conventional solid-state sintering. 3+ / Ta 5+ Effective solid solution of ions in the BIT lattice.

[0033] To gain a deeper understanding of Sb 3+ / Ta 5+ The lattice transformation induced by co-doping was refined using Rietveld refinement of the XRD data using FullProf software. For example... Figure 2 As shown in (ad), the refined fitting curves agree well with the experimental data (Chi2≤3, RP≤11%), indicating that the refined model can accurately reflect the characteristic crystal structure of the material. Figure 2 The lattice parameter variation pattern shown in (e) clearly reveals the Sb 3+ / Ta 5+ The effect of co-doping on the crystal structure of BIT-based ceramics: with the increase of Sb 3+ / Ta 5+ As the co-doping concentration increased from 0.01 to 0.03, the cell volume V expanded from 968.835 ų to 969.072 ų. This lattice expansion phenomenon originates from the fact that the radius of the dopant ions is larger than that of Ti. 4+ Sb 3+ (Ionic radius 0.76 Å when coordination number CN=6) and Ta 5+ The radii of the ions (0.64 Å when CN=6) are all larger than those of the substituted Ti in the crystal lattice. 4+ (The ionic radius is 0.605 Å when CN=6). Furthermore, the contraction along the a-axis and the expansion along the b-axis indicate that the [TiO6]oxy octahedron undergoes tilting distortion, which is conducive to the polarization reversal process and thus promotes the improvement of the material's piezoelectric response.

[0034] Figure 3 For BIT ceramics and Sb 3+ / Ta 5+ Surface grain morphology of co-doped ceramics. Observation reveals that all samples exhibit anisotropic growth of lamellar grains, a typical characteristic of bismuth layered ferroelectric ceramics. Among them, the pure BIT sample shows abnormally elongated grains surrounded by uniformly distributed fine grains. This phenomenon can be attributed to the small precursor particle size or uneven particle size distribution of the calcined powder, leading to rapid grain growth along the c-axis. Compared to BIT ceramics, Sb... 3+ / Ta 5+ Co-doped ceramics exhibit larger lamellar grains due to their higher sintering temperature; and with the increase of Sb... 3+ / Ta5+ The grain size gradually decreases as the doping amount increases from 0.01 to 0.03. This change can be attributed to the decrease of oxygen vacancy concentration in the ceramic (which will be discussed later): the decrease of oxygen vacancy concentration inhibits ion diffusion during densification and slows down the grain boundary diffusion rate. When the doping amount reaches 0.03 (high doping concentration), irregular blocky grains appear on the surface of the sample in addition to the small grains; this can be attributed to the accumulation of lattice stress due to the increase of doping concentration, which triggers structural instability.

[0035] To study the relative density of the BIT-based ceramic, the density of the ceramic at different doping concentrations was determined by the Archimedes method. As shown in Table 1, the relative density of the BIT ceramic increases from 89.6% to 92.6% as the doping amount increases from 0.01 to 0.03. 3+ / Ta 5+ Co-doping can improve the relative density of the BIT-based piezoelectric ceramic; when the co-doping concentration x = 0.02, the relative density of the ceramic reaches a maximum value of 92.6%.

[0036] Table 1 Relative density values of BIT, BITST1, BITST2, and BITST3 ceramic samples.

[0037] Figure 4 (a) is the room temperature piezoelectric coefficient of the BITST ceramic. Sb 3+ / Ta 5+ Co-doping can significantly improve the piezoelectric performance of the ceramic, and the piezoelectric coefficient d 33 of the BITST2 ceramic is 25.1 pC / N, which is higher than that of the pure BIT ceramic (4.2 pC / N). To evaluate the thermal depolarization behavior of the piezoelectric performance of the BITST ceramic, gradient annealing experiments were performed on all samples in the temperature range of 30-700 ℃, and the holding time at each temperature point was 2 h. As shown in Figure 4 (b), the piezoelectric coefficient of all samples gradually decreases as the annealing temperature increases, which is due to the gradual recovery of the domains to the initial state under thermal field excitation. When the annealing temperature is 500 ℃, the d 33 of the BITST2 ceramic remains at 23.3 pC / N, which is 93% of the initial value; when the annealing temperature further approaches the Curie temperature, the piezoelectric coefficient of all samples sharply decreases to near zero, indicating that the sample has undergone a ferroelectric-paraelectric phase transition.

[0038] Figure 5 (a) is the room temperature piezoelectric coefficient of the BITST ceramic. Sb 3+ / Ta 5+Dielectric constant-temperature curves of co-doped ceramics at 100 kHz. All samples show a sharp dielectric anomaly peak in the tested temperature range, which corresponds to the ferroelectric-paraelectric phase transition of the material, and the temperature at which the peak occurs is the Curie temperature (TC). It is known that the Curie temperature of bismuth layer-structured ferroelectric ceramics is closely related to the lattice distortion, and as Sb 3+ / Ta 5+ The Curie temperature of BITST ceramics decreases from 673 °C of pure BIT to 644 °C of BITST3 with the increase of co-doping concentration. This phenomenon can be attributed to the lattice distortion caused by the mismatch of ionic radius and chemical valence between Sb 3+ / Ta 5+ ion and Ti 4+ The mismatch of ionic radius and chemical valence leads to significant lattice distortion of the crystal structure. Figure 5 (b) is the dielectric loss (tan δ) - temperature curve of BITSTx ceramics. It is worth noting that when the Sb 3+ / Ta 5+ The dielectric loss of the ceramics decreases significantly when the co-doping concentration exceeds 0.01; especially in the temperature range below 500 °C, the dielectric loss of BITST2 and BITST3 ceramics is less than 0.01. The decrease of dielectric loss is closely related to the increase of material density and the decrease of oxygen vacancy concentration.

[0039] In addition to piezoelectric and dielectric properties, resistivity also has an important influence on vibration sensing performance. Figure 6 (a) is the BIT ceramic and Sb 3+ / Ta 5+ Resistivity-temperature curves of co-doped ceramics. The resistivity of all samples gradually decreases with increasing temperature, indicating that the carriers inside the ceramics are gradually activated by heat. At 500 °C, the resistivity of BITST2 ceramic reaches the highest value (8.1 × 10 6 Ω·cm), which is 3 orders of magnitude higher than that of pure BIT ceramic (8.1 × 10 3 Ω·cm); this resistivity level is at a relatively high level in BIT-based ceramics with a piezoelectric coefficient d 33 > 25 pC / N. This high resistivity characteristic is mainly due to the increase of material density and the decrease of oxygen vacancy concentration.

[0040] The resistivity-temperature relationship of bismuth layer-structured ferroelectric can be divided into two characteristic intervals, which can be explained by the Arrhenius equation (1). Figure 6 (b) is the fitting result of the two intervals, and the Arrhenius equation is as follows: In the formula, p 0 is the pre-exponential factor, E awhere k is the Boltzmann constant, k B where k is the Boltzmann constant, T where T is the absolute temperature.

[0041] The fitted curves can be clearly divided into low-temperature region (≤350 ℃) and high-temperature region (≥350 ℃), and the activation energy data obtained by fitting are shown in Table 2. The results show that the activation energy of pure BIT ceramic is the highest in the low-temperature region, but it is still lower than 1.1 eV, which is basically consistent with the activation energy of double ionized oxygen vacancies, indicating that the conduction mechanism of the sample in this temperature range is mainly defect and oxygen vacancy conduction. In the high-temperature region, the activation energy of pure BIT ceramic is only 0.6877 eV, indicating that it is still the main conduction mode of oxygen vacancy conduction. While the activation energy of Sb 3+ / Ta 5+ The activation energy of co-doped samples shows an upward trend, and the activation energy value is close to half of the material band gap, indicating that the sample changes to intrinsic conduction mechanism in the high-temperature region after co-doping.

[0042] Table 2 The conductive activation energy values of BIT, BITST1, BITST2, BITST3 ceramic samples in low-temperature and high-temperature sections.

[0043] Figure 7 where Bi4Ti 3-2x (SbTa) x O 12 (x=0, 0.01, 0.02, 0.03) ceramics in the temperature range of 400-550 °C. Generally, the impedance spectrum is composed of low-frequency region, medium-frequency region and high-frequency region, which correspond to the contributions of electrode effect, grain boundary effect and grain effect, respectively. With the increase of temperature, the impedance of all samples shows a downward trend; and it is found that after Sb 3+ / Ta 5+ doping, the impedance of all ceramic samples is significantly higher than that of pure BIT ceramic, in which the sample impedance reaches the maximum value when the Sb 3+ / Ta 5+ doping amount x=0.02. The impedance spectrum of pure BIT ceramic can be decomposed into two semicircles, corresponding to grain effect and grain boundary effect, respectively; while the impedance spectrum of Sb 3+ / Ta 5+ co-doped ceramic sample is approximately a semicircle, and the semicircle is mainly dominated by grain effect. This transformation from "double semicircle" to "single semicircle" indicates that the insulation performance of BIT ceramic is significantly improved after Sb 3+ / Ta 5+ doping.

[0044] Oxygen vacancies have a crucial impact on the electrical properties of BIT piezoelectric ceramics, and can even lead to ferroelectric domain pinning. Oxygen vacancies are common point defects in piezoelectric ceramics, increasing the internal carrier concentration and inducing local electric field or charge accumulation, thus significantly affecting the electrical properties of the ceramics. To analyze the characteristics of oxygen vacancies, X-ray photoelectron spectroscopy (XPS) was used to characterize the O1s energy levels of BIT and BITST2 ceramics. Figure 8 As shown, by fitting the Gaussian-Lorentz function peaks, the O1s spectrum can be decomposed into three characteristic peaks, corresponding to the binding energy states of three oxygen-containing compounds: the O1s(I) peak with the lowest binding energy corresponds to lattice oxygen (O_Lattice); the other two non-lattice oxygen peaks (O_Non-lattice) – O1s(II) (medium binding energy) and O1s(III) (highest binding energy) – have binding energies higher than that of the O1s(I) peak. Specifically, the generation of the O1s(II) peak is related to lattice defects caused by the volatilization of bismuth oxide during sintering, while the O1s(III) peak originates from organic oxygen components adsorbed on the material surface. This study compares and analyzes the oxygen vacancy density in ceramics by comparing the peak area ratio of non-lattice oxygen to lattice oxygen.

[0045] In BIT-based piezoelectric ceramics, oxygen vacancy defects mainly originate from the volatilization of low-melting-point (≈825℃) bismuth oxide, and the defect formation process can be represented by the following reaction formula: The oxygen vacancy concentration can be estimated by the peak area ratio of amorphous oxygen to lattice oxygen (results summarized in Table 3). Clearly, the oxygen vacancy concentration in BITST2 ceramics is slightly lower than that in pure BIT ceramics. This reduction stems from the following defect transformation mechanism: Normally, Sb 3+ / Ta 5+ Through co-substitution of Ti 4+ The charge neutrality of ceramics can be maintained by the self-compensation of charge, as shown in reaction formulas (3) to (4); however, during high-temperature sintering, some Sb 3+ It will be converted to Sb 5+ And Sb 5+ For Ti 4+ Substitution can directly reduce the oxygen vacancy concentration (reaction (5)), a process that gives the doped sample high resistivity. Furthermore, the Ta-O bond energy (≈799.1 kJ / mol) is higher than the Ti-O bond energy (≈674.2 kJ / mol), and Ta... 5+ The substituted oxygen atoms have a stronger binding ability and make it more difficult for oxygen vacancies to form, which further promotes the reduction of oxygen vacancy concentration in BITST2 ceramics.

[0046] Table 3 O 1s fine spectrum fitting results of BIT and BITST2 ceramics In summary, the present application successfully prepared Bi4Ti 3-2x (SbTa) x O 12 (x=0-0.03) ceramics by solid state reaction method. Experimental results show that Sb 3+ / Ta 5+ co-doping can significantly improve the piezoelectric and electrical properties of BIT-based ceramics. Specifically, Sb 3+ / Ta 5+ co-doping makes the piezoelectric coefficient d 33 of BIT ceramics increase from 4.1 pC / N to 25.1 pC / N; after annealing at 500 ℃, the d 33 of the co-doped ceramics can still retain 93% of the initial value, and maintain a low dielectric loss (<0.01). More importantly, the resistivity of BIT ceramics is significantly improved by co-doping, which is about 3 orders of magnitude higher than that of undoped BIT ceramics, and its resistivity can reach 8.1×10 6 Ω·cm at 500 ℃, which is at a high level in BIT-based ceramics with d 33 >25 pC / N. This excellent performance is due to the increase in material density and the decrease in oxygen vacancy concentration. This study provides a feasible solution for simultaneously improving the piezoelectric and electrical properties of BIT ceramics through reasonable Sb 3 + / Ta 5+ co-doping strategy, which is of great significance for the development of high-performance and high-reliability high-temperature piezoelectric vibration sensors.

Claims

1. A type of Sb 3+ / Ta 5+ Co-doped bismuth titanate-based piezoelectric ceramics, characterized in that: Its chemical formula is Bi4Ti 3-2x (SbTa) x O 12 ; Where 0.01≤x≤0.

03.

2. The Sb as described in claim 1 3+ / Ta 5+ Co-doped bismuth titanate-based piezoelectric ceramics, characterized in that: The Sb 3+ / Ta 5+ d-type co-doped bismuth titanate-based piezoelectric ceramics 33 It is 25.1 pC / N.

3. The Sb as described in claim 1 3+ / Ta 5+ Co-doped bismuth titanate-based piezoelectric ceramics, characterized in that: The Sb 3+ / Ta 5+ The resistivity of co-doped bismuth titanate-based piezoelectric ceramics at 500 °C is 8.1 × 10⁻⁶. 6 Ω·cm.

4. The Sb as described in claim 1 3+ / Ta 5+ A method for preparing co-doped bismuth titanate-based piezoelectric ceramics, characterized in that: Includes the following steps: According to Bi4Ti 3-2x (SbTa) x O 12 According to the stoichiometric ratio, the raw materials TiO2, Bi2O3, Ta2O5 and Sb2O3 were weighed, ball-milled, dried and calcined; After calcination, the powder is ball-milled a second time, a binder is added, it is molded, the binder is removed, and then sintered to obtain the final product.

5. The Sb as described in claim 4 3+ / Ta 5+ A method for preparing co-doped bismuth titanate-based piezoelectric ceramics, characterized in that: The medium used in the first ball mill is ethanol; The medium used in the second ball milling process is ethanol.

6. The Sb as described in claim 4 3+ / Ta 5+ A method for preparing co-doped bismuth titanate-based piezoelectric ceramics, characterized in that: The drying temperature is 60 °C.

7. The Sb as described in claim 4 3+ / Ta 5+ A method for preparing co-doped bismuth titanate-based piezoelectric ceramics, characterized in that: The calcination temperature is 825℃; The sintering temperature is 1050~1140℃.

8. The Sb as described in claim 4 3+ / Ta 5+ A method for preparing co-doped bismuth titanate-based piezoelectric ceramics, characterized in that: The compression molding pressure is 150 MPa.

9. The Sb as described in claim 4 3+ / Ta 5+ A method for preparing co-doped bismuth titanate-based piezoelectric ceramics, characterized in that: The adhesive is polyvinyl alcohol.

10. The Sb as described in claim 1 3+ / Ta 5+ The application of co-doped bismuth titanate-based piezoelectric ceramics is characterized by: Used to manufacture vibration sensors with operating temperatures above 500 °C.

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