Barium calcium zirconate titanate-sodium bismuth zirconate lead-free piezoelectric ceramic material as well as preparation method and application thereof

Abstract

The invention relates to a barium calcium zirconate titanate-sodium bismuth zirconate lead-free piezoelectric ceramic material and a preparation method and application thereof, the general formula of the ceramic material is (1-x) (Ba0. 85Ca0. 15Zr0. 1Ti0. 9O3)-x (Bi0. 5Na0. 5ZrO3), x is the molar percentage of Bi0. 5Na0. 5ZrO3 in the ceramic material, and x is greater than or equal to 0.30% and less than or equal to 1.80%. Compared with the prior art, the Ba < 0.85 > Ca < 0.15 > Zr < 0.1 > Ti < 0.9 > O < 3 > is subjected to doping modification through Bi < 0.5 > Na < 0.5 > ZrO < 3 >, so that the sintering temperature of the ceramic is reduced, and the targets of energy conservation and emission reduction are met. Meanwhile, the obtained ceramic material has a high piezoelectric constant and low dielectric loss, and has good electrical properties.

Description

Technical Field

[0001] This invention relates to the field of piezoelectric ceramics technology, and in particular to a lead-free piezoelectric ceramic material of barium calcium zirconate titanate and sodium bismuth zirconate, its preparation method and application. Background Technology

[0002] Piezoelectric ceramics are structurally stable, simple to prepare, and inexpensive materials. As a type of polycrystalline functional material prepared through solid-state reaction sintering, piezoelectric ceramics have wide applications in electromechanical conversion devices such as transducers, sensors, and energy harvesters due to their unique direct and inverse piezoelectric effects. Currently, lead-based piezoelectric ceramics have long dominated the market due to their excellent electromechanical properties and temperature stability. However, the lead oxide content in the raw materials used to prepare lead-based piezoelectric materials is as high as 60% or more, and lead is highly volatile at high temperatures. Furthermore, lead-based piezoelectric ceramics easily release highly toxic substances during preparation, use, and disposal, posing a serious threat to the ecological environment and human health. In recent years, with the increasing global emphasis on sustainable development strategies and growing environmental awareness, countries around the world have successively introduced laws restricting the use of lead-containing electronic materials. Therefore, the lead-free transformation of piezoelectric ceramics has become an inevitable trend, and the development of high-performance lead-free piezoelectric ceramics is of great significance.

[0003] Lead-free piezoelectric ceramics can be broadly categorized into three types based on their crystal structure: tungsten bronze-based lead-free piezoelectric ceramics, bismuth layered lead-free piezoelectric ceramics, and perovskite-based lead-free piezoelectric ceramics. Tungsten bronze-based lead-free piezoelectric ceramics possess high spontaneous strength and high Curie temperature, along with a low dielectric constant, making them suitable for high-frequency sensors and pyroelectric devices. However, their significantly low piezoelectric constant makes it difficult to meet the requirements of mainstream transducers. Bismuth layered lead-free piezoelectric ceramics exhibit low dielectric constant, high Curie temperature, and significant anisotropy in piezoelectric properties, making them suitable for high-temperature, high-frequency environments. However, their low piezoelectric activity and high coercive field strength lead to polarization difficulties, severely limiting their practical applications. Perovskite-based lead-free piezoelectric ceramics combine high piezoelectric performance with compatibility with traditional lead-based material processing. Their piezoelectric performance can be optimized through doping, making them considered the optimal candidate system to replace lead-based PZT.

[0004] Perovskite-type BCZT lead-free piezoelectric ceramics (Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 BaTiO3 (BCZT) is an excellent BaTiO3-based dielectric material, but it suffers from drawbacks such as high sintering temperature and a significantly lower piezoelectric coefficient compared to lead-based PZT, which severely restricts its application in practical production. Therefore, it is necessary to synergistically optimize the BCZT system to broaden its application in the piezoelectric field.

[0005] Patent CN116063074A discloses a ceramic material with high energy storage density, its preparation method, and its applications. The ceramic material is prepared by hot-pressing sintering of bismuth sodium niobate-doped modified calcium barium zirconate titanate-based energy storage ceramic. The general formula of the ceramic material is (1-x)(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-x(Na 0.7 Bi 0.1 NbO3), where 0.03 ≤ x ≤ 0.12. Raw materials were weighed according to the stoichiometric formula and mixed evenly to form a complete batch. The complete batch was then ball-milled, dried, ground, and sieved sequentially to form a sieved material. The sieved material was pressed into samples, and the samples were hot-pressed and sintered, successfully preparing a dense and uniform energy storage ceramic. The obtained ceramic can achieve a high energy storage density (5.32 J / cm³) at a high breakdown field strength (620 kV / cm). 3 This ceramic material exhibits high energy storage density and efficiency (>90%), with high efficiency effectively preventing the release of stored energy as heat and extending the material's lifespan. However, this ceramic material focuses on the field of dielectric energy storage ceramics, aiming to achieve high energy storage density and high energy storage efficiency under high electric fields, with a piezoelectric constant (d...). 33 The core electrical performance indicators, such as dielectric constant, are difficult to meet the requirements of the piezoelectric ceramics field. Summary of the Invention

[0006] The purpose of this invention is to provide a lead-free piezoelectric ceramic material of barium calcium zirconate titanate and sodium bismuth zirconate, as well as its preparation method and application, which has excellent electrical properties.

[0007] The objective of this invention can be achieved through the following technical solution: a lead-free piezoelectric ceramic material of barium calcium zirconate titanate-bismuth sodium zirconate (BCZT-BNZ), wherein the general formula of the ceramic material is as follows:

[0008] (1-x)(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-x(Bi 0.5 Na 0.5 ZrO3), where x is Bi 0.5 Na 0.5 The molar percentage of ZrO3 in ceramic materials is 0.30% ≤ x ≤ 1.80%.

[0009] The ceramic material of this invention is Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 Using O3(BCZT) as the matrix, Bi is innovatively introduced. 0.5Na 0.5 ZrO3(BNZ) is used as a composite dopant, and its general chemical formula is: (1-x)(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-x(Bi 0.5 Na 0.5 ZrO3). The dopant BNZ and its modification strategy used in this invention can optimize the piezoelectric active phase structure of BCZT and promote domain wall motion, thereby improving d 33 The piezoelectric constant solves the bottleneck problem in the application of BCZT materials in the field of piezoelectric ceramics.

[0010] More preferably, 0.50% ≤ x ≤ 1.50%.

[0011] In this invention, x cannot be too high or too low, otherwise it will lead to a decrease in the ferroelectric properties and an increase in dielectric loss in the piezoelectric ceramic of this invention.

[0012] Preferably, the ceramic material has a single perovskite phase structure.

[0013] Preferably, the average grain size of the ceramic material is 8.50 to 13.00 μm.

[0014] Preferably, the piezoelectric constant of the ceramic material is 400-500 pC / N.

[0015] Preferably, the dielectric loss of the ceramic material at room temperature is 1.60% to 2.50%.

[0016] Preferably, the room temperature dielectric constant of the ceramic material is 4100 to 4800.

[0017] Preferably, the oxygen vacancy concentration of the ceramic material is 20% to 35%.

[0018] Preferably, the sintering temperature of the ceramic material is between 1300℃ and 1500℃.

[0019] A method for preparing the above-mentioned lead-free piezoelectric ceramic material of barium calcium zirconate titanate and sodium bismuth zirconate includes the following steps:

[0020] Will Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3 and Bi 0.5 Na 0.5 The ZrO3 mixed powder is sequentially granulated, pressed, debinded, and sintered to obtain the ceramic material.

[0021] Preferably, the Ba 0.85 Ca0.15 Zr 0.1 Ti 0.9 O3 and Bi 0.5 Na 0.5 The residue of the ZrO3 mixed powder passing through a 120-mesh sieve is ≤5%.

[0022] Preferably, the Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3 and Bi 0.5 Na 0.5 The preparation method of ZrO3 mixed powder includes the following steps:

[0023] According to the general chemical formula (1-x)(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-x(Bi 0.5 Na 0.5 According to the stoichiometric ratio shown in the figure (ZrO3), analytical grade BaCO3, CaCO3, ZrO2, TiO2, Bi2O3, and Na2CO3 were weighed, ball-milled, mixed, dried, and calcined to obtain the BaCO3. 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3 and Bi 0.5 Na 0.5 ZrO3 mixed powder.

[0024] More preferably, the calcination temperature is 900℃~1100℃, and the calcination time is 4h~6h.

[0025] More preferably, the calcination temperature is 1000℃~1100℃, and the calcination time is 5h~6h.

[0026] More preferably, the ball milling is performed using a wet ball milling method.

[0027] More preferably, the ball mill specifically includes:

[0028] Anhydrous ethanol was used as the milling medium, and zirconia balls were used as the milling balls. The milling was carried out in a nylon jar.

[0029] In this invention, the ball milling equipment can be conventional equipment using existing technology.

[0030] More preferably, the ball mill rotation speed is 300 r / min to 400 r / min, and the ball milling time is 10 to 12 h.

[0031] More preferably, during ball milling, the mass ratio of anhydrous ethanol, grinding balls, and powder (i.e., raw material) is (1-2):(1-3):1.

[0032] More preferably, the amount of residue on a 120-mesh sieve after ball milling is ≤5%.

[0033] More preferably, the ball milling step is followed by a drying step at 80°C to 120°C.

[0034] Preferably, the granulation step uses PVA (polyvinyl alcohol) as a binder for wet granulation.

[0035] More preferably, the granulation step specifically includes:

[0036] Will Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3 and Bi 0.5 Na 0.5 ZrO3 mixed powder was mixed with PVA aqueous solution to form a molding process.

[0037] More preferably, the concentration of the PVA aqueous solution is 5 wt% to 8 wt%.

[0038] More preferably, the mass of the PVA aqueous solution is Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3 and Bi 0.5 Na 0.5 The ZrO3 mixed powder comprises 8% to 15% of the total mass, preferably 10% to 15%.

[0039] Preferably, the compression molding step includes: holding pressure at 6-15 MPa for 30-60 seconds.

[0040] More preferably, the compression molding step includes: holding pressure at 10-15 MPa for 40-60 seconds.

[0041] Preferably, the adhesive removal step includes: treating at 500℃~600℃ for 4h~6h.

[0042] More preferably, the adhesive removal step includes: treating at 550℃~600℃ for 5h~6h.

[0043] Preferably, the sintering step includes sintering at 1300℃~1500℃ for 2h~3h.

[0044] More preferably, the sintering step includes sintering at 1300℃~1400℃ for 2.5h~3h.

[0045] An application of the above-mentioned lead-free piezoelectric ceramic material, namely barium calcium zirconate titanate and sodium bismuth zirconate, is to use the ceramic material for mechanical energy conversion and harvesting in transportation infrastructure.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. This invention involves doping BCZT ceramic with x molar fractions of Bi. 0.5 Na 0.5 Using ZrO3 as the second component significantly reduces oxygen vacancy concentration and leakage current density, while increasing residual polarization and maximum polarization, thus preparing lead-free piezoelectric ceramics with excellent electrical properties.

[0048] 2. This invention utilizes BNZ doping to form a low-temperature eutectic liquid phase, achieving near-fully dense sintering at 1300℃ and preventing component volatilization. Compared to the sintering temperature of 1550℃ for traditional BCZT ceramics, energy consumption is reduced by approximately 20%.

[0049] 3. This invention constructs a quasi-isomorphic phase boundary (MPB) structure similar to that in lead-based piezoelectric ceramics within the BCZT system, in Ba... 0.85 Ca 0.15 Zr 0.1 Ti 0.9 Introducing the regulatory compound Bi into the O3 matrix 0.5 Na 0.5 ZrO3 is used to construct the nanoscale trigonal (R)-orthorhombic (O)-tetragonal (T) three-phase coexistence phase boundary in the room temperature region, thereby improving the comprehensive performance of BCZT-based ceramics.

[0050] 4. This invention precisely controls the OT (orthogonal-tetragonal) phase boundary transition temperature within the range of 20-35℃, making it highly compatible with the typical road service environment temperature. This design significantly promotes the activity of ferroelectric domain walls and optimizes piezoelectric performance by utilizing the high polarization response characteristics of the phase boundary region, thereby greatly improving the mechanical energy to electrical energy conversion efficiency. This characteristic makes the ceramic material particularly suitable for vibration energy harvesting systems in transportation infrastructure, providing key technical support for sustainable energy supply under road loads.

[0051] 5. The preparation conditions of this invention are easy to control, and it is highly practical. It does not require additional conditions such as high pressure, atmosphere, or quenching, and has good repeatability and stability, which is conducive to large-scale industrial production.

[0052] 6. The piezoelectric ceramic material of this invention has excellent substitution potential for PZT-based ceramics, effectively avoiding environmental pollution and health hazards caused by lead.

[0053] 7. This invention delves into the mechanism of regulating BCZT lattice distortion and defects, continues the previously established high-uniformity powder synthesis process, and innovatively selects Bi... 0.5 Na 0.5 The ZrO3 dopant, using a traditional atmospheric pressure sintering process, significantly improves the piezoelectric coefficient at low temperatures. The lead-free piezoelectric ceramic material described in this invention exhibits excellent sintering characteristics, easily controllable process conditions, and strong practicality, facilitating large-scale industrial production.

[0054] 8. Traditional BCZT ceramics require sintering above 1550℃ to achieve high density, but high temperatures cause the volatilization of elements such as Bi / Na, deteriorating electrical properties. This invention uses BNZ doping to form a low-temperature eutectic liquid phase, achieving near-fully dense sintering at 1300℃, thus avoiding component volatilization and reducing energy consumption by approximately 20%. The Bi in BNZ... 3+ Na + Introducing enhanced A-site ion shift polarization, Zr 4+ Suppressing the generation of oxygen vacancies and synergistically enhancing the maximum polarization intensity (P) max ) and remanent polarization intensity (P r At the same time, it reduces the dielectric loss to a minimum of 1.65%, which is better than the reported similar BCZT system (such as the (1-x)BCZT-xKNNLN lead-free piezoelectric ceramic in patent CN 114276137 A with tanδ = 2.50%). Attached Figure Description

[0055] Figure 1 The image shows the XRD pattern of the ceramic material prepared in Example 1 of this invention.

[0056] Figure 2 The image shows the XRD pattern of the ceramic material prepared in Example 2 of this invention.

[0057] Figure 3 The image shows the XRD pattern of the ceramic material prepared in Example 3 of this invention.

[0058] Figure 4 The image shows the XRD pattern of the ceramic material prepared in Comparative Example 1 of this invention.

[0059] Figure 5 The image shows the XRD pattern of the ceramic material prepared in Comparative Example 2 of this invention.

[0060] Figure 6 This is a SEM image of the ceramic material prepared in Example 1 of the present invention.

[0061] Figure 7 This is a SEM image of the ceramic material prepared in Example 2 of the present invention.

[0062] Figure 8This is a SEM image of the ceramic material prepared in Example 3 of the present invention.

[0063] Figure 9 This is a SEM image of the ceramic material prepared in Comparative Example 1 of the present invention.

[0064] Figure 10 This is a SEM image of the ceramic material prepared in Comparative Example 2 of the present invention.

[0065] Figure 11 The image shows the PE hysteresis loop of the ceramic material prepared in Example 1 of this invention under an electric field strength of 10 Hz and 30 kV / cm.

[0066] Figure 12 The image shows the PE hysteresis loop of the ceramic material prepared in Example 2 of this invention under an electric field strength of 10 Hz and 30 kV / cm.

[0067] Figure 13 The image shows the PE hysteresis loop of the ceramic material prepared in Example 3 of this invention under an electric field strength of 10 Hz and 30 kV / cm.

[0068] Figure 14 The image shows the PE hysteresis loop of the ceramic material prepared in Comparative Example 1 of this invention under an electric field strength of 10 Hz and 30 kV / cm.

[0069] Figure 15 The image shows the PE hysteresis loop of the ceramic material prepared in Comparative Example 2 of this invention under an electric field strength of 10 Hz and 30 kV / cm.

[0070] Figure 16 The dielectric temperature spectrum of the ceramic material prepared in Example 1 of this invention is shown at a test frequency of 10 kHz.

[0071] Figure 17 The dielectric temperature spectrum of the ceramic material prepared in Example 2 of this invention is shown at a test frequency of 10 kHz.

[0072] Figure 18 The dielectric temperature spectrum of the ceramic material prepared in Example 3 of this invention is shown at a test frequency of 10 kHz.

[0073] Figure 19 The dielectric temperature spectrum of the ceramic material prepared in Comparative Example 1 of this invention is shown at a test frequency of 10 kHz.

[0074] Figure 20 The dielectric temperature spectrum of the ceramic material prepared in Comparative Example 2 of this invention is shown at a test frequency of 10 kHz.

[0075] Figure 21The above is the XPS energy spectrum of the oxygen element in the ceramic material prepared in Example 1 of this invention.

[0076] Figure 22 This is the XPS energy spectrum of the oxygen element in the ceramic material prepared in Example 2 of the present invention.

[0077] Figure 23 The above is the XPS energy spectrum of the oxygen element in the ceramic material prepared in Example 3 of this invention.

[0078] Figure 24 The above is the XPS energy spectrum of the oxygen element in the ceramic material prepared in Comparative Example 1 of this invention.

[0079] Figure 25 The above is the XPS energy spectrum of the oxygen element in the ceramic material prepared in Comparative Example 2 of this invention.

[0080] Figure 26 This is a summary diagram of the dielectric temperature spectra of the ceramic materials prepared in Examples 1-3 and Comparative Example 2 of the present invention at a test frequency of 10 kHz. Detailed Implementation

[0081] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0082] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers.

[0083] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, apparatus, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, apparatus, and materials similar to or equivalent to those described, apparatus, and materials in the embodiments of this invention may be used to implement the present invention.

[0084] The present invention provides a ceramic material, wherein the general formula of the ceramic material is as follows:

[0085] (1-x)(Ba 0.85 Ca 0.15Zr 0.1 Ti 0.9 O3)-x(Bi 0.5 Na 0.5 ZrO3), wherein 0.30% ≤ x ≤ 1.80%.

[0086] Preferably, x is 0.50% ≤ x ≤ 1.50%.

[0087] Preferably, the ceramic material of the present invention has an average grain size of 8.50 μm to 13.00 μm; a sintering temperature of 1300℃ to 1500℃; a piezoelectric constant of 400 to 500 pC / N; and a dielectric loss of 1.60% to 2.50%.

[0088] The method for preparing the ceramic material of the present invention includes the following steps:

[0089] (1) According to the general chemical formula (1-x)(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-x(Bi 0.5 Na 0.5 According to the stoichiometric ratio shown in the figure (ZrO3), weigh out analytical grade BaCO3, CaCO3, ZrO2, TiO2, Bi2O3 and Na2CO3 respectively.

[0090] (2) Weigh out BaCO3, CaCO3, ZrO2, TiO2, Bi2O3, and Na2CO3 and add them to a ball mill jar for a first ball milling process. After thorough mixing, remove the mixture and place it in an oven for drying. After drying, pass it through a 120-mesh sieve to obtain the primary ball-milled material. The primary ball milling process uses anhydrous ethanol as the milling medium, with a mass ratio of anhydrous ethanol, milling balls, and raw materials of (1-2):(1-3):1. The ball milling speed is 300-400 r / min, and the milling time is 10-12 h. When drying the ball-milled mixture, the oven temperature is 100℃, and the drying time is 4 h. The residue of the dried powder passing through a 120-mesh sieve is ≤5%.

[0091] (3) Pour the primary ball milling material obtained in step (2) into a crucible and place it in a muffle furnace for pre-firing. The pre-firing temperature is 900-1100℃ and the pre-firing time is 4-6h.

[0092] (4) After grinding the pre-calcined material obtained in step (3) in a mortar, it is then placed in a ball mill jar for secondary ball milling. After thorough mixing, it is removed and placed in an oven for drying. After drying, it is passed through a 120-mesh sieve to obtain the secondary ball-milled material. In the secondary ball milling process, anhydrous ethanol is used as the ball milling medium, and the mass ratio of anhydrous ethanol, grinding balls and raw materials is 1.2:2:1; the ball milling speed is 300-400 r / min, and the ball milling time is 10-12 h; when drying the mixed slurry after ball milling, the oven temperature is 80-100℃; the residue of the dried powder passing through a 120-mesh sieve is ≤5%.

[0093] (5) Add a 5-8 wt% PVA aqueous solution to the secondary ball milling material obtained in step (4) and granulate to obtain a powder with good flowability. Take an appropriate amount of powder and put it into a tablet press for tableting to obtain a dense and uniform preform. The mass of the PVA aqueous solution added is 8-15% of the mass of the secondary ball milling material; the press pressure is 6-15 MPa, and the holding pressure is 30-60 s; the mass of each preform is 0.4-0.6 g.

[0094] (6) The blank obtained in step (5) is debinded and sintered to obtain the lead-free piezoelectric ceramic material. The debinding temperature is 500-600℃ and the holding time is 4-6h; the sintering temperature is 1300-1500℃ and the holding time is 2-3h.

[0095] (7) The ceramic material sintered in step (6) is subjected to simple grinding, silver plating and sintering on both sides, polarized and tested for its piezoelectric and ferroelectric properties. Among them, the grinding is to a thickness of about 0.07 mm; the silver plating temperature is 600℃ and the holding time is 30 min; the polarization electric field strength is 4 KV / mm and the polarization time is 30 min.

[0096] The following detailed description is based on specific embodiments.

[0097] Example 1

[0098] In this embodiment, the chemical formula of the ceramic material is as follows: 0.995(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-0.005(Bi 0.5 Na 0.5 ZrO3 was prepared according to the following steps:

[0099] (1) According to the general chemical formula 0.995(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-0.005(Bi 0.5Na 0.5 According to the stoichiometric ratio shown in the figure (ZrO3), weigh out analytical grade BaCO3, CaCO3, ZrO2, TiO2, Bi2O3 and Na2CO3 respectively.

[0100] (2) Weigh out BaCO3, CaCO3, ZrO2, TiO2, Bi2O3, and Na2CO3 and add them to a ball mill jar for a first ball milling process. After thorough mixing, remove the mixture and place it in an oven for drying. After drying, pass it through a 120-mesh sieve to obtain the primary ball-milled material. The primary ball milling process uses anhydrous ethanol as the milling medium, with a mass ratio of anhydrous ethanol, milling balls, and raw materials of 1:2:1. The milling speed is 300 r / min, and the milling time is 10 h. When drying the ball-milled mixture, the oven temperature is 100℃, and the drying time is 4 h. The residue of the dried powder passing through a 120-mesh sieve is ≤5%.

[0101] (3) Pour the primary ball milling material obtained in step (2) into a crucible and place it in a muffle furnace for pre-firing. The pre-firing temperature is 1100℃ and the pre-firing time is 5h.

[0102] (4) After grinding the pre-calcined material obtained in step (3) in a mortar, it is then placed in a ball mill jar for secondary ball milling. After thorough mixing, it is removed and placed in an oven for drying. After drying, it is passed through a 120-mesh sieve to obtain the secondary ball-milled material. In the secondary ball milling process, anhydrous ethanol is used as the ball milling medium, and the mass ratio of anhydrous ethanol, grinding balls and raw materials is 1.2:2:1; the ball milling speed is 300 r / min, and the ball milling time is 10 h; when drying the mixed slurry after ball milling, the oven temperature is 100℃, and the drying time is 4 h; the residue of the dried powder passing through a 120-mesh sieve is ≤5%.

[0103] (5) Add an 8wt% PVA aqueous solution to the secondary ball milling material obtained in step (4) and granulate to obtain a powder with good flowability. Take an appropriate amount of powder and put it into a tablet press for tableting to obtain a dense and uniform preform. The mass of the PVA aqueous solution added is 15% of the mass of the secondary ball milling material; the press is loaded with a pressure of 10MPa and held for 50s; the mass of each preform is 0.5g.

[0104] (6) The blank obtained in step (5) is debonded and sintered to obtain the lead-free piezoelectric ceramic material. The debonding temperature is 560℃ and the holding time is 6h; the sintering temperature is 1450℃ and the holding time is 2h.

[0105] (7) The ceramic material sintered in step (6) is subjected to simple grinding, silver plating and sintering on both sides, polarized and tested for its piezoelectric and ferroelectric properties. Among them, the grinding is to a thickness of about 0.07 mm; the silver plating temperature is 600℃ and the holding time is 30 min; the polarization electric field strength is 4 KV / mm and the polarization time is 30 min.

[0106] Figure 1 The image shows the XRD pattern of the ceramic material prepared in Example 1. As can be seen from the image, the obtained ceramic material has a pure perovskite structure.

[0107] Figure 6 The image shows the SEM image of the ceramic material prepared in Example 1. As can be seen from the image, the obtained ceramic material has a dense structure and relatively uniform grain size, with an average grain size of 10.27 μm.

[0108] Figure 11 The PE hysteresis loop of the ceramic material under an electric field strength of 10 Hz and 30 kV / cm is shown. The results show that the maximum polarization intensity of the ceramic in Example 1 is 20.59 μC / cm. 2 The remanent polarization intensity is 11.65 μC / cm. 2 .

[0109] Figure 16 The dielectric temperature spectrum of the ceramic material prepared in Example 1 is shown at 10 kHz. The results show that the room temperature dielectric constant of the ceramic in Example 1 is 4158 and the dielectric loss is 1.69%.

[0110] Figure 21 The XPS spectrum of the oxygen element in the ceramic material prepared in Example 1 shows that the oxygen vacancy rate in Example 1 is 35.01%.

[0111] The performance indices of the ceramic material obtained in Example 1 are shown in Table 1.

[0112] Example 2

[0113] In this embodiment, the chemical formula of the ceramic material is shown as: 0.990(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)0.010(Bi 0.5 Na 0.5 ZrO3 was prepared according to the following steps:

[0114] (1) According to the general chemical formula 0.990(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-0.010(Bi0.5 Na 0.5 According to the stoichiometric ratio shown in the figure (ZrO3), weigh out analytical grade BaCO3, CaCO3, ZrO2, TiO2, Bi2O3 and Na2CO3 respectively.

[0115] (2) Weigh out BaCO3, CaCO3, ZrO2, TiO2, Bi2O3, and Na2CO3 and add them to a ball mill jar for a first ball milling process. After thorough mixing, remove the mixture and place it in an oven for drying. After drying, pass it through a 120-mesh sieve to obtain the primary ball-milled material. The primary ball milling process uses anhydrous ethanol as the milling medium, with a mass ratio of anhydrous ethanol, milling balls, and raw materials of 1:2:1. The milling speed is 300 r / min, and the milling time is 10 h. When drying the ball-milled mixture, the oven temperature is 100℃, and the drying time is 4 h. The residue of the dried powder passing through a 120-mesh sieve is ≤5%.

[0116] (3) Pour the primary ball milling material obtained in step (2) into a crucible and place it in a muffle furnace for pre-firing. The pre-firing temperature is 1050℃ and the pre-firing time is 5h.

[0117] (4) After grinding the pre-calcined material obtained in step (3) in a mortar, it is then placed in a ball mill jar for secondary ball milling. After thorough mixing, it is removed and placed in an oven for drying. After drying, it is passed through a 120-mesh sieve to obtain the secondary ball-milled material. In the secondary ball milling process, anhydrous ethanol is used as the ball milling medium, and the mass ratio of anhydrous ethanol, grinding balls and raw materials is 1.2:2:1; the ball milling speed is 300 r / min, and the ball milling time is 10 h; when drying the mixed slurry after ball milling, the oven temperature is 100℃, and the drying time is 4 h; the residue of the dried powder passing through a 120-mesh sieve is ≤5%.

[0118] (5) Add an 8wt% PVA aqueous solution to the secondary ball milling material obtained in step (4) and granulate to obtain a powder with good flowability. Take an appropriate amount of powder and put it into a tablet press for tableting to obtain a dense and uniform preform. The mass of the PVA aqueous solution added is 15% of the mass of the secondary ball milling material; the press is loaded with a pressure of 10MPa and held for 50s; the mass of each preform is 0.5g.

[0119] (6) The blank obtained in step (5) is debonded and sintered to obtain the lead-free piezoelectric ceramic material. The debonding temperature is 560℃ and the holding time is 6h; the sintering temperature is 1350℃ and the holding time is 2h.

[0120] (7) The ceramic material sintered in step (6) is subjected to simple grinding, silver plating and sintering on both sides, polarized and tested for its piezoelectric and ferroelectric properties. Among them, the grinding is to a thickness of about 0.07 mm; the silver plating temperature is 600℃ and the holding time is 30 min; the polarization electric field strength is 4 KV / mm and the polarization time is 30 min.

[0121] Figure 2 The image shows the XRD pattern of the ceramic material prepared in Example 2. As can be seen from the image, the obtained ceramic material has a pure perovskite structure.

[0122] Figure 7 The image shows the SEM image of the ceramic material prepared in Example 2. As can be seen from the image, the obtained ceramic material has a dense structure and relatively uniform grain size, with an average grain size of 12.19 μm.

[0123] Figure 12 The PE hysteresis loop of the ceramic material under an electric field strength of 10 Hz and 30 kV / cm is shown. The results show that the maximum polarization intensity of the ceramic in Example 1 is 25.50 μC / cm. 2 The remanent polarization intensity is 14.68 μC / cm. 2 .

[0124] Figure 17 The dielectric temperature spectrum of the ceramic material prepared in Example 2 is shown at 10 kHz. The results show that the room temperature dielectric constant of the ceramic in Example 2 is 4730 and the dielectric loss is 1.65%.

[0125] Figure 22 The XPS energy spectrum of the ceramic material prepared in Example 2 shows that the oxygen vacancy rate is 20.77%.

[0126] The performance indices of the ceramic material obtained in Example 2 are shown in Table 1.

[0127] Example 3

[0128] In this embodiment, the chemical formula of the ceramic material is shown as: 0.985(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)0.015(Bi 0.5 Na 0.5 ZrO3 was prepared according to the following steps:

[0129] (1) According to the general chemical formula 0.985(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-0.015(Bi0.5 Na 0.5 According to the stoichiometric ratio shown in the figure (ZrO3), weigh out analytical grade BaCO3, CaCO3, ZrO2, TiO2, Bi2O3 and Na2CO3 respectively.

[0130] (2) Weigh out BaCO3, CaCO3, ZrO2, TiO2, Bi2O3, and Na2CO3 and add them to a ball mill jar for a first ball milling process. After thorough mixing, remove the mixture and place it in an oven for drying. After drying, pass it through a 120-mesh sieve to obtain the primary ball-milled material. The primary ball milling process uses anhydrous ethanol as the milling medium, with a mass ratio of anhydrous ethanol, milling balls, and raw materials of 1:2:1. The milling speed is 300 r / min, and the milling time is 10 h. When drying the ball-milled mixture, the oven temperature is 100℃, and the drying time is 4 h. The residue of the dried powder passing through a 120-mesh sieve is ≤5%.

[0131] (3) Pour the primary ball milling material obtained in step (2) into a crucible and place it in a muffle furnace for pre-firing. The pre-firing temperature is 1000℃ and the pre-firing time is 5h.

[0132] (4) After grinding the pre-calcined material obtained in step (3) in a mortar, it is then placed in a ball mill jar for secondary ball milling. After thorough mixing, it is removed and placed in an oven for drying. After drying, it is passed through a 120-mesh sieve to obtain the secondary ball-milled material. In the secondary ball milling process, anhydrous ethanol is used as the ball milling medium, and the mass ratio of anhydrous ethanol, grinding balls and raw materials is 1.2:2:1; the ball milling speed is 300 r / min, and the ball milling time is 10 h; when drying the mixed slurry after ball milling, the oven temperature is 100℃, and the drying time is 4 h; the residue of the dried powder passing through a 120-mesh sieve is ≤5%.

[0133] (5) Add an 8wt% PVA aqueous solution to the secondary ball milling material obtained in step (4) and granulate to obtain a powder with good flowability. Take an appropriate amount of powder and put it into a tablet press for tableting to obtain a dense and uniform preform. The mass of the PVA aqueous solution added is 15% of the mass of the secondary ball milling material; the press is loaded with a pressure of 10MPa and held for 50s; the mass of each preform is 0.5g.

[0134] (6) The blank obtained in step (5) is debinded and sintered to obtain the lead-free piezoelectric ceramic material. The debinding temperature is 560℃ and the holding time is 6h; the sintering temperature is 1300℃ and the holding time is 2h.

[0135] (7) The ceramic material sintered in step (6) is subjected to simple grinding, silver plating and sintering on both sides, polarized and tested for its piezoelectric and ferroelectric properties. Among them, the grinding is to a thickness of about 0.07 mm; the silver plating temperature is 600℃ and the holding time is 30 min; the polarization electric field strength is 4 KV / mm and the polarization time is 30 min.

[0136] Figure 3 The image shows the XRD pattern of the ceramic material prepared in Example 3. As can be seen from the image, the obtained ceramic material has a pure perovskite structure.

[0137] Figure 8 The image shows the SEM image of the ceramic material prepared in Example 3. As can be seen from the image, the obtained ceramic material has a dense structure and relatively uniform grain size, with an average grain size of approximately 8.67 μm.

[0138] Figure 13 The PE hysteresis loop of the ceramic material under an electric field strength of 10 Hz and 30 kV / cm is shown. The results show that the maximum polarization intensity of the ceramic in Example 1 is 22.63 μC / cm. 2 The remanent polarization intensity is 15.25 μC / cm. 2 .

[0139] Figure 18 The dielectric temperature spectrum of the ceramic material prepared in Example 3 is shown at 10 kHz. The results show that the room temperature dielectric constant of the ceramic in Example 3 is 4120 and the dielectric loss is 2.30%.

[0140] Figure 23 The XPS energy spectrum of the ceramic material prepared in Example 3 shows that the oxygen vacancy rate is 25.67%.

[0141] The performance index of the ceramic material obtained in Example 3 is shown in Table 1.

[0142] Comparative Example 1

[0143] In this comparative example, the calcium barium zirconate titanate-based ceramic was not modified. The chemical formula of the calcium barium zirconate titanate-based ceramic is shown as: Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3 was prepared according to the following steps:

[0144] (1) According to the general chemical formula Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 The stoichiometric ratios shown in O3 are used to weigh out analytical grade BaCO3, CaCO3, ZrO2, and TiO2, respectively.

[0145] (2) Weigh out BaCO3, CaCO3, ZrO2, and TiO2 and add them to a ball mill jar for a first ball milling process. After thorough mixing, remove the mixture and place it in an oven for drying. After drying, pass it through a 120-mesh sieve to obtain the primary ball-milled material. In the primary ball milling process, anhydrous ethanol was used as the milling medium, with a mass ratio of anhydrous ethanol, milling balls, and raw materials of 1:2:1. The milling speed was 300 r / min, and the milling time was 10 h. When drying the mixed slurry after ball milling, the oven temperature was 100℃, and the drying time was 4 h. The residue of the dried powder passing through a 120-mesh sieve was ≤5%.

[0146] (3) Pour the primary ball milling material obtained in step (2) into a crucible and place it in a muffle furnace for pre-firing. The pre-firing temperature is 1200℃ and the pre-firing time is 5h.

[0147] (4) After grinding the pre-calcined material obtained in step (3) in a mortar, it is then placed in a ball mill jar for secondary ball milling. After thorough mixing, it is removed and placed in an oven for drying. After drying, it is passed through a 120-mesh sieve to obtain the secondary ball-milled material. In the secondary ball milling process, anhydrous ethanol is used as the ball milling medium, and the mass ratio of anhydrous ethanol, grinding balls and raw materials is 1.2:2:1; the ball milling speed is 300 r / min, and the ball milling time is 10 h; when drying the mixed slurry after ball milling, the oven temperature is 100℃, and the drying time is 4 h; the residue of the dried powder passing through a 120-mesh sieve is ≤5%.

[0148] (5) Add an 8wt% PVA aqueous solution to the secondary ball milling material obtained in step (4) and granulate to obtain a powder with good flowability. Take an appropriate amount of powder and put it into a tablet press for tableting to obtain a dense and uniform preform. The mass of the PVA aqueous solution added is 15% of the mass of the secondary ball milling material; the press is loaded with a pressure of 10MPa and held for 50s; the mass of each preform is 0.5g.

[0149] (6) The blank obtained in step (5) is debonded and sintered to obtain the lead-free piezoelectric ceramic material. The debonding temperature is 560℃ and the holding time is 6h; the sintering temperature is 1550℃ and the holding time is 3h.

[0150] (7) The ceramic material sintered in step (6) is subjected to simple grinding, silver plating and sintering on both sides, polarized and tested for its piezoelectric and ferroelectric properties. Among them, the grinding is to a thickness of about 0.07 mm; the silver plating temperature is 600℃ and the holding time is 30 min; the polarization electric field strength is 4 KV / mm and the polarization time is 30 min.

[0151] Figure 4The image shows the XRD pattern of the calcium barium zirconate titanate-based ceramic prepared in Comparative Example 1. As can be seen from the image, the obtained ceramic has a pure perovskite structure.

[0152] Figure 9 The image shows a SEM image of the calcium barium zirconate titanate-based ceramic prepared in Comparative Example 1. As can be seen from the image, the obtained ceramic has a dense structure and relatively uniform grain size, with an average grain size of approximately 24.00 μm.

[0153] Figure 14 The PE hysteresis loop of the ceramic material under an electric field strength of 10 Hz and 30 kV / cm is shown. The results show that the maximum polarization intensity of the ceramic in the comparative example is 16.20 μC / cm. 2 The remanent polarization intensity is 9.05 μC / cm. 2 .

[0154] Figure 19 The dielectric temperature spectrum of the ceramic material prepared in Comparative Example 1 at 10 kHz is shown. The results show that the room temperature dielectric constant of the ceramic in Comparative Example 1 is 3662 and the dielectric loss is 2.31%.

[0155] Figure 24 The XPS spectrum of oxygen in the ceramic material prepared in Comparative Example 1 shows that the oxygen vacancy rate in the comparative example is 36.46%.

[0156] The performance indices of the ceramic material obtained in Comparative Example 1 are shown in Table 1.

[0157] Comparative Example 2

[0158] In Comparative Example 2, the chemical formula of the ceramic material is shown: 0.980 (Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)0.020(Bi 0.5 Na 0.5 ZrO3 was prepared according to the following steps:

[0159] (1) According to the general chemical formula 0.980(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-0.020(Bi 0.5 Na 0.5 According to the stoichiometric ratio shown in the figure (ZrO3), weigh out analytical grade BaCO3, CaCO3, ZrO2, TiO2, Bi2O3 and Na2CO3 respectively.

[0160] (2) Weigh out BaCO3, CaCO3, ZrO2, TiO2, Bi2O3, and Na2CO3 and add them to a ball mill jar for a first ball milling process. After thorough mixing, remove the mixture and place it in an oven for drying. After drying, pass it through a 120-mesh sieve to obtain the primary ball-milled material. The primary ball milling process uses anhydrous ethanol as the milling medium, with a mass ratio of anhydrous ethanol, milling balls, and raw materials of 1:2:1. The milling speed is 300 r / min, and the milling time is 10 h. When drying the ball-milled mixture, the oven temperature is 100℃, and the drying time is 4 h. The residue of the dried powder passing through a 120-mesh sieve is ≤5%.

[0161] (3) Pour the primary ball milling material obtained in step (2) into a crucible and place it in a muffle furnace for pre-firing. The pre-firing temperature is 1000℃ and the pre-firing time is 5h.

[0162] (4) After grinding the pre-calcined material obtained in step (3) in a mortar, it is then placed in a ball mill jar for secondary ball milling. After thorough mixing, it is removed and placed in an oven for drying. After drying, it is passed through a 120-mesh sieve to obtain the secondary ball-milled material. In the secondary ball milling process, anhydrous ethanol is used as the ball milling medium, and the mass ratio of anhydrous ethanol, grinding balls and raw materials is 1.2:2:1; the ball milling speed is 300 r / min, and the ball milling time is 10 h; when drying the mixed slurry after ball milling, the oven temperature is 100℃, and the drying time is 4 h; the residue of the dried powder passing through a 120-mesh sieve is ≤5%.

[0163] (5) Add an 8wt% PVA aqueous solution to the secondary ball milling material obtained in step (4) and granulate to obtain a powder with good flowability. Take an appropriate amount of powder and put it into a tablet press for tableting to obtain a dense and uniform preform. The mass of the PVA aqueous solution added is 15% of the mass of the secondary ball milling material; the press is loaded with a pressure of 10MPa and held for 50s; the mass of each preform is 0.5g.

[0164] (6) The blank obtained in step (5) is debonded and sintered to obtain the lead-free piezoelectric ceramic material. The debonding temperature is 560℃ and the holding time is 6h; the sintering temperature is 1250℃ and the holding time is 2h.

[0165] (7) The ceramic material sintered in step (6) is subjected to simple grinding, silver plating and sintering on both sides, polarized and tested for its piezoelectric and ferroelectric properties. Among them, the grinding is to a thickness of about 0.07 mm; the silver plating temperature is 600℃ and the holding time is 30 min; the polarization electric field strength is 4 KV / mm and the polarization time is 30 min.

[0166] Figure 5The image shows the XRD pattern of the ceramic material prepared in Comparative Example 2. As can be seen from the image, the obtained ceramic material has a pure perovskite structure.

[0167] Figure 10 The image shows the SEM image of the ceramic material prepared in Comparative Example 2. As can be seen from the image, the obtained ceramic material has a dense structure and relatively uniform grain size, with an average grain size of approximately 7.80 μm.

[0168] Figure 15 The PE hysteresis loop of the ceramic material under an electric field strength of 10 Hz and 30 kV / cm is shown. The results show that the maximum polarization intensity of the ceramic in Comparative Example 2 is 21.79 μC / cm. 2 The remanent polarization intensity is 14.95 μC / cm. 2 .

[0169] Figure 20 The dielectric temperature spectrum of the ceramic material prepared in Comparative Example 2 at 10 kHz is shown. The results show that the room temperature dielectric constant of the ceramic in Comparative Example 2 is 4342 and the dielectric loss is 2.83%.

[0170] Figure 25 The XPS spectrum of oxygen in the ceramic material prepared in Comparative Example 2 shows that the oxygen vacancy rate in Comparative Example 2 is 34.86%.

[0171] The performance indices of the ceramic material obtained in Comparative Example 2 are shown in Table 1.

[0172] Comparative Example 3

[0173] Patent CN 114276137 A discloses a KNNLN-doped BCZT ceramic with the composition formula (1-x)(Ba 0.85 Ca 0.15 Zr 0.08 Ti 0.92 )-x(K 0.5 Na 0.5 (NbO3-LiNbO3). After solid-state sintering at 1200℃ and holding for 4 h, a silver electrode was coated on the ceramic surface. After electrode sintering, it was polarized in silicone oil with an electric field strength of 4 kV / mm for 30 min. The piezoelectric constant d of this KNNLN-doped BCZT ceramic is... 33 It has a dielectric constant of 315 pC / N and a dielectric constant ε. r The dielectric constant is 1357, and the dielectric loss tanδ is 2.50%. Although this scheme achieves lead-free properties, it suffers from low dielectric constant and insufficient piezoelectric performance.

[0174] Table 1. Energy storage characteristics of ceramic materials in each embodiment and comparative example.

[0175]

[0176] Based on the data in the table above, it can be seen that this invention successfully prepared high-performance lead-free piezoelectric ceramic materials through chemical formula design and precise control of process parameters such as sintering temperature, with an average grain size of approximately 8.50 μm to 13.00 μm. When the doping amount x = 1.00%, the overall electrical performance reaches its optimal value: piezoelectric constant (d... 33 The dielectric constant (ε) at room temperature is 490 pC / N. r The dielectric constant is 4730, the dielectric loss is 1.65%, and the remanent polarization (Pr) is 14.68 μC / cm. 2 Compared to undoped BCZT ceramics (piezoelectric constant (d...),... 33 = 400 pC / N, dielectric constant at room temperature (ε) r =3662, dielectric loss = 2.31%, remanent polarization (Pr) = 9.05 μC / cm 2 The oxygen vacancy concentration of BNZ-doped BCZT ceramics is significantly reduced, which effectively reduces the domain wall pinning effect and suppresses leakage current, thereby comprehensively improving the electrical performance.

[0177] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A lead-free piezoelectric ceramic material consisting of barium calcium zirconate titanate and sodium bismuth zirconate, characterized in that, The general formula for the ceramic material is as follows: (1-x)(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-x(Bi 0.5 Na 0.5 ZrO3), where x is Bi 0.5 Na 0.5 The molar percentage of ZrO3 in ceramic materials is 0.30% ≤ x ≤ 1.80%.

2. The lead-free piezoelectric ceramic material of barium calcium zirconate titanate-bismuth sodium zirconate according to claim 1, characterized in that, The ceramic material has a single perovskite phase structure with an average grain size of 8.50–13.00 μm.

3. The lead-free piezoelectric ceramic material of barium calcium zirconate titanate-bismuth sodium zirconate according to claim 1, characterized in that, The piezoelectric constant of the ceramic material is 400–500 pC / N; And / or, the dielectric loss of the ceramic material at room temperature is 1.60% to 2.50%; And / or, the oxygen vacancy concentration of the ceramic material is 20% to 35%.

4. A method for preparing the lead-free piezoelectric ceramic material of barium calcium zirconate titanate-bismuth sodium zirconate according to any one of claims 1 to 3, characterized in that, Includes the following steps: Will Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3 and Bi 0.5 Na 0.5 The ZrO3 mixed powder is sequentially granulated, pressed, debinded, and sintered to obtain the ceramic material.

5. The preparation method of the lead-free piezoelectric ceramic material of barium calcium zirconate titanate-bismuth sodium zirconate according to claim 4, characterized in that, The Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3 and Bi 0.5 Na 0.5 The preparation method of ZrO3 mixed powder includes the following steps: According to the general chemical formula (1-x)(Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3)-x(Bi 0.5 Na 0.5 According to the stoichiometric ratio shown in the figure (ZrO3), analytical grade BaCO3, CaCO3, ZrO2, TiO2, Bi2O3, and Na2CO3 were weighed, ball-milled, mixed, dried, and calcined to obtain the BaCO3. 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3 and Bi 0.5 Na 0.5 ZrO3 mixed powder.

6. The method for preparing the lead-free piezoelectric ceramic material of barium calcium zirconate titanate-bismuth sodium zirconate according to claim 5, characterized in that, The calcination temperature is 900℃~1100℃, and the calcination time is 4h~6h; And / or, the ball milling is a wet ball milling process, and the residue of the powder after ball milling is ≤5% when passing through a 120-mesh sieve; And / or, the ball milling process further includes a drying step at 80°C to 120°C.

7. The preparation method of the lead-free piezoelectric ceramic material of barium calcium zirconate titanate-bismuth sodium zirconate according to claim 6, characterized in that, The ball mill specifically includes: Anhydrous ethanol was used as the milling medium, and zirconia balls were used as the milling balls. The milling was carried out in a nylon jar. And / or, the ball mill rotation speed is 300 r / min to 400 r / min, and the ball milling time is 10 h to 12 h; And / or, during ball milling, the mass ratio of anhydrous ethanol, grinding balls and powder is (1-2):(1-3):

1.

8. The preparation method of the lead-free piezoelectric ceramic material of barium calcium zirconate titanate-bismuth sodium zirconate according to claim 4, characterized in that, The granulation step uses PVA as a binder for wet granulation. And / or, the compression molding step includes: processing at 6-15 MPa for 30-60 s; And / or, the glue removal step includes: treating at 500℃~600℃ for 4h~6h; And / or, the sintering step includes: sintering at 1300℃~1500℃ for 2h~3h.

9. The preparation method of the lead-free piezoelectric ceramic material of barium calcium zirconate titanate-bismuth sodium zirconate according to claim 8, characterized in that, The granulation step specifically includes: Will Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3 and Bi 0.5 Na 0.5 ZrO3 mixed powder was mixed with PVA aqueous solution and molded; And / or, the concentration of the PVA aqueous solution is 5wt% to 8wt%; And / or, the mass of the PVA aqueous solution is Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O3 and Bi 0.5 Na 0.5 The ZrO3 mixed powder comprises 8% to 15% of the total mass.

10. The application of the lead-free piezoelectric ceramic material of barium calcium zirconate titanate-bismuth sodium zirconate according to any one of claims 1 to 3, characterized in that, The ceramic material is used for the mechanical energy conversion and harvesting of transportation infrastructure.

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