Low-temperature sintering PZT-based piezoelectric ceramic material, preparation method and application thereof

Abstract

This invention belongs to the field of piezoelectric ceramic materials technology, and discloses a low-temperature sintered PZT-based piezoelectric ceramic material, its preparation method, and its application. The chemical composition of the low-temperature sintered PZT-based piezoelectric ceramic material of this invention is 0.38Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 The compound is LBPBSC with a content of 0.38Pb(MgO)₂O₃ + a%, where LBPBSC is nano-sized PbO-B₂O₃-SiO₂-Li₂O-Bi₂O₃-CuO glass powder. The molar ratio of PbO, B₂O₃, SiO₂, Li₂O, Bi₂O₃, and CuO in LBPBSC is (35-40):(10-15):(5-8):(10-15):(10-12):(5-10). The mass of LBPBSC is 0.38Pb(MgO)₂O₃ + a%. 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 The mass of O3 is a%, 0.5≤a≤0.6. The material of this invention can be sintered at temperatures below 900℃, and after sintering, it has high density and excellent electrical properties, meeting the application requirements of piezoelectric ceramic components.

Description

Technical Field

[0001] This invention belongs to the field of piezoelectric ceramic materials technology, specifically relating to a low-temperature sintered PZT-based piezoelectric ceramic material, its preparation method, and its application. Background Technology

[0002] In recent years, due to the large-scale use of piezoelectric actuators and transformers, high-power piezoelectric ceramic materials have attracted widespread research and attention. To achieve high power density, multilayer piezoelectric ceramic components have gradually become a recent research hotspot. Multilayer devices, represented by piezoelectric actuators, have specific requirements for the performance of piezoelectric materials, generally requiring high piezoelectric constants, electromechanical coupling coefficients, dielectric constants, and low losses. PMN-PZT piezoelectric ceramics possess high piezoelectric constants, high stability and density, and moderate dielectric losses, making them suitable for multilayer piezoelectric ceramic components and showing broad application prospects, thus attracting significant attention from researchers.

[0003] However, PMN-PZT piezoelectric ceramics have a high sintering temperature of 1260℃. During high-temperature sintering, PbO volatilization is severe, leading to a shift in the stoichiometry and a decrease in the ceramic's electrical properties. Furthermore, current methods for achieving multilayer structures tend to use Ag-Pd noble metals with higher melting points as internal electrodes, stacked in multiple layers and sintered in a single operation; however, such multilayer devices are expensive. If PZT piezoelectric ceramics could be sintered below 900℃, Ag could be used as the internal electrode, which would not only reduce costs but also suppress PbO volatilization.

[0004] Low-temperature sintering of piezoelectric ceramics using liquid-phase sintering is the most common and economical method. Currently, research on low-temperature sintering aids mainly focuses on low-melting-point glass frits and low-melting-point compounds, among which oxides such as ZnO, Bi₂O₃, Li₂CO₃, and B₂O₃ are frequently used as sintering aids. One mechanism by which these oxides lower the sintering temperature is to distort the crystal lattice, reduce the potential barrier between electric domains, and accelerate ion diffusion, but this severely degrades the performance of piezoelectric ceramics. Another mechanism involves generating a low-melting-point liquid phase through low-melting-point glass / oxides or forming a solid solution with substances in the piezoelectric ceramic. However, the temperature at which the liquid phase forms is often above 900℃, making it impossible to achieve at lower sintering temperatures. Furthermore, the introduction of an extraneous second phase after the final firing of the piezoelectric ceramic inevitably affects its electrical properties. Therefore, developing a PZT-based piezoelectric ceramic material that balances low sintering temperature and excellent electrical properties, while avoiding the shortcomings of the methods described above, is a key technical challenge in this field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the shortcomings of the existing technology by providing a low-temperature sintering PZT-based piezoelectric ceramic material, its preparation method and application. This material can be sintered at a temperature below 900°C, and after sintering, it has high density and excellent electrical properties, meeting the application requirements of piezoelectric ceramic components.

[0006] To address the technical problem proposed in this invention, this invention provides a low-temperature sintered PZT-based piezoelectric ceramic material with a chemical composition of 0.38Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 The product is LBPBSC with a content of 0.38Pb(MgO) + a%. LBPBSC is a nano-sized PbO-B₂O₃-SiO₂-Li₂O-Bi₂O₃-CuO glass powder. The molar ratio of PbO, B₂O₃, SiO₂, Li₂O, Bi₂O₃, and CuO in LBPBSC is (35–40):(10–15):(5–8):(10–15):(10–12):(5–10). The mass of LBPBSC is 0.38Pb(MgO) + a%. 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 a% of the mass of O3, 0.5≤a≤0.6.

[0007] The above scheme includes the following steps in the preparation method of LBPBSC:

[0008] 1) Dissolve lithium acetate, bismuth acetate, copper acetate, lead acetate, boric acid, and silicon acetate separately in anhydrous ethanol, and heat and stir to form a sol;

[0009] 2) Mix and stir the sols of each group to form a mixed sol, then dry to obtain a dry gel;

[0010] 3) The dry gel was heat-treated in a muffle furnace to obtain LBPBSC.

[0011] Furthermore, the heating and stirring temperature is 40–50°C, and the stirring time is 1–3 hours.

[0012] Furthermore, the drying temperature is 60–80°C.

[0013] Furthermore, the temperature of the heat treatment is 450–550°C.

[0014] Furthermore, the particle size of the LBPBSC is 200–300 nm.

[0015] This invention also provides a method for preparing a low-temperature sintered PZT-based piezoelectric ceramic material, specifically including the following steps:

[0016] S1, based on chemical composition 0.38Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 PbO, MgO, Nb2O5, ZrO2 and TiO2 were weighed, ball-milled and mixed evenly, dried and sieved. The mixed powder was pressed into blocks, pre-fired in a muffle furnace, ball-milled into powder, and dried to obtain PZT-based piezoelectric ceramic matrix powder.

[0017] S2, the ceramic matrix powder is ball-milled and mixed with LBPBSC, dried and sieved to obtain low-temperature sintered PZT-based piezoelectric ceramic powder;

[0018] S3 involves adding a binder to low-temperature sintered PZT-based piezoelectric ceramic powder, forming it, removing the binder, sintering it, polishing the sintered ceramic, coating it with silver paste, and then calcining and polarizing it to obtain low-temperature sintered PZT-based piezoelectric ceramic material.

[0019] In the above scheme, the ball milling mixing time in step S1 is 24 to 48 hours.

[0020] In the above scheme, in step S1, the sieving is performed through an 80-100 mesh sieve.

[0021] In the above scheme, the pre-firing temperature is 900-950℃, and the pre-firing time is 2-4 hours. When the pre-firing temperature is too low or the pre-firing time is too short, the solid-phase reaction between the powders is insufficient, incomplete, or even no solid-phase reaction occurs, which seriously reduces the performance of the piezoelectric ceramic. When the pre-firing temperature is too high or the pre-firing time is too long, the PbO in the ceramic matrix volatilizes violently, causing the stoichiometric ratio to deviate, which is not conducive to the control of the ceramic matrix composition.

[0022] In the above scheme, the particle size of the PZT-based piezoelectric ceramic matrix powder is 0.5 to 1 μm.

[0023] In the above scheme, the ball milling mixing time in step S2 is 24-48 hours.

[0024] In the above scheme, the particle size of the low-temperature sintered PZT-based piezoelectric ceramic powder is <1μm.

[0025] In the above scheme, the adhesive is a PVA solution with a mass fraction of 5-15%.

[0026] In the above scheme, the amount of binder added is 0.3 to 0.5% of the mass of the low-temperature sintered PZT-based piezoelectric ceramic powder.

[0027] In the above scheme, the molding process involves granulation followed by pressing, with a pressing pressure of 10-20 MPa.

[0028] In the above scheme, the glue discharge temperature is 500-600℃, the heating rate is 1-2℃ / min, and the glue discharge time is 2-4h.

[0029] In the above scheme, the sintering temperature is 850-900℃ and the sintering time is 2-4h.

[0030] In the above scheme, the calcination temperature is 650-730℃ and the calcination time is 0.5-1h.

[0031] In the above scheme, the polarization is carried out in silicone oil at 120-140°C, the polarization electric field strength is 3-3.5 kV / mm, and the polarization time is 20-30 min.

[0032] This invention also provides an application of a low-temperature sintered PZT-based piezoelectric ceramic material for the preparation of piezoelectric ceramic components.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1) This invention targets 0.38Pb(Mg) in a PZT ceramic matrix. 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6To address this issue, a specific sintering aid, LBPBSC, was developed for this matrix. LBPBSC is a nanoscale multi-element glass powder prepared by the sol-gel method, capable of forming a glass phase at a lower temperature. When added to the PZT ceramic matrix, it is uniformly dispersed between the pores of the PZT ceramic particles, creating a capillary effect. Through liquid-phase sintering, it accelerates the diffusion and mass transfer process between the ceramic matrices, forming a synergistic effect and significantly reducing the sintering temperature of the PZT ceramic. The PZT ceramic matrix in this invention is a typical soft piezoelectric ceramic. To minimize the "hard" doping of the powder by elements in the glass powder, the main raw materials for the glass are PbO and SiO2. This ensures the formation of a glass phase while minimizing the impact on the PZT matrix. Simultaneously, Cu, Bi, B, and Li are introduced to adjust the... The softening temperature of the glass powder is controlled to minimize the introduction of "hard" dopants. Specifically, the Pb in LBPBSC is essentially the same as that in PZT ceramics, minimizing its impact on the electrical properties of the piezoelectric ceramics. CuO and Bi₂O₃ not only generate liquid phases themselves but also form eutectic liquid phases with PbO in PZT, significantly reducing the amount of sintering aids required. B₂O₃ has a small ionic radius and good cooling properties, making it less likely to substitute ions with the main crystalline phase when its content is low, thus maintaining the high piezoelectric properties of PZT ceramics. SiO₂ acts as a network former in the glass, facilitating the formation of amorphous glass. Li₂O serves as an external network, making the glass structure porous, lowering the softening temperature, and allowing the glass phase to form at lower temperatures.

[0035] 2) The PZT-based piezoelectric ceramic material of this invention can be sintered at temperatures below 900°C. X-ray diffraction (XRD) testing confirmed that the synthesized product has a single perovskite structure. Scanning electron microscopy (SEM) testing further confirmed that the piezoelectric ceramic sintered at low temperatures has high density and uniform grain size. The PZT-based piezoelectric ceramic material of this invention also possesses excellent electrical properties, exhibiting a large piezoelectric constant (d). 33 With a high dielectric constant (≥500 Pc / N) and a large dielectric coupling coefficient (Kp≥0.6), the PZT-based piezoelectric ceramic material of this invention fully meets the application requirements of LTCC process and multilayer stacked piezoelectric ceramic components. When applied to multilayer piezoelectric ceramic components, silver electrodes can be used instead of expensive silver-palladium electrodes, reducing production costs and effectively avoiding the diffusion of silver elements, thus showing good application prospects. Attached Figure Description

[0036] Figure 1 The image shows the XRD pattern of the low-temperature sintered PZT-based piezoelectric ceramic material prepared in Example 1 of this invention.

[0037] Figure 2This is a SEM image of the low-temperature sintered PZT-based piezoelectric ceramic material prepared in Example 1 of the present invention.

[0038] Figure 3 The images shown are SEM images and EDS elemental distribution diagrams of the cross-section of the stacked actuator prepared in Example 1 of this invention. (a), (b), (c), and (d) are SEM images of the cross-section of the stacked actuator, and (e), (f), (g), and (h) are distribution diagrams of Ag, Ti, Zr, and Pb elements in the cross-sectional area of ​​Figure (d), respectively. Detailed Implementation

[0039] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0040] In the following examples, the purity of PbO, MgO, Nb2O5, ZrO2, and TiO2 used was all above 99%; the lithium acetate, bismuth acetate, copper acetate, lead acetate, boric acid, and silicon acetate used were all analytical grade (AR).

[0041] Example 1

[0042] The chemical composition of the low-temperature sintered PZT-based piezoelectric ceramic material in this embodiment is as follows:

[0043] 0.38Pb(Mg 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 O3 + 0.5% LBPBSC

[0044] LBPBSC is a nano-sized PbO-B2O3-SiO2-Li2O-Bi2O3-CuO glass powder. The molar ratio of PbO, B2O3, SiO2, Li2O, Bi2O3, and CuO in LBPBSC is 35:10:5:10:10:5. The preparation method of LBPBSC includes the following steps:

[0045] 1) Dissolve lithium acetate, bismuth acetate, copper acetate, lead acetate, boric acid, and silicon acetate in anhydrous ethanol, and stir with a magnetic stirrer at 50°C for 1 hour to form a sol.

[0046] 2) Mix and stir the sols of each group to form a mixed sol, and dry it at 80°C to obtain a dry gel;

[0047] 3) The dried gel was heat-treated in a muffle furnace at 500°C to obtain LBPBSC with a particle size of 200 nm. The preparation method of the low-temperature sintered PZT-based piezoelectric ceramic material in this embodiment includes the following steps:

[0048] S1, based on chemical composition 0.38Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 PbO, MgO, Nb2O5, ZrO2 and TiO2 were weighed and ball-milled for 24 hours. After drying, the mixture was passed through an 80-mesh sieve. The mixed powder was pressed into blocks and kept at 950℃ in a muffle furnace for 4 hours. It was then ball-milled into powder and dried to obtain PZT-based piezoelectric ceramic matrix powder with a particle size of 0.5-1μm.

[0049] S2, the ceramic matrix powder is ball-milled with 0.5% (by weight) of LBPBSC for 24 hours, dried, and sieved to obtain low-temperature sintered PZT-based piezoelectric ceramic powder with a particle size <1μm; the ball milling process in steps S1 and S2 is as follows: deionized water is used as solvent, zirconia balls are used as ball milling media, the mass ratio of material, balls and water is 1:1.5:1, and the ball milling speed is 100r / min;

[0050] S3. A 5% PVA solution was added to the low-temperature sintered PZT-based piezoelectric ceramic powder. The amount of PVA solution added was 0.3% of the mass of the low-temperature sintered PZT-based piezoelectric ceramic powder. The powder was granulated and then pressed into ceramic sheets with a diameter of 19 mm and a thickness of 1 mm. The ceramic sheets were heated to 600 °C at a rate of 1 °C / min and held for 2 h to remove the binder. Then, they were sintered at 850 °C for 4 h to form ceramic. The sintered ceramic was polished, coated with silver paste, calcined at 650 °C for 0.5 h, and then polarized in silicone oil at 120 °C with a polarization electric field strength of 3 kV / mm and a polarization time of 30 min. After cleaning and aging for 24 h, the low-temperature sintered PZT-based piezoelectric ceramic material was obtained.

[0051] Figure 1 The image shows the XRD pattern of the low-temperature sintered PZT-based piezoelectric ceramic material prepared in this embodiment. As can be seen from the image, the position and relative intensity of each diffraction peak of the synthesized product are consistent with the standard JCPDS card (88-1867) of PZT, indicating that the synthesized product has a single perovskite structure.

[0052] Figure 2 The image shows a SEM image of the low-temperature sintered PZT-based piezoelectric ceramic material prepared in this embodiment. As can be seen from the image, the ceramic grains are tightly bonded, have high density, uniform grain size distribution, and a grain size of 0.8–1.2 μm. Therefore, this is beneficial to the movement of domain walls in the piezoelectric ceramic and the improvement of piezoelectric properties.

[0053] Application Example 1

[0054] The low-temperature sintered PZT-based piezoelectric ceramic material from Example 1 is used to fabricate a multilayer actuator, specifically including the following steps:

[0055] S1, based on chemical composition 0.38Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 PbO, MgO, Nb2O5, ZrO2 and TiO2 were weighed and ball-milled for 24 hours. After drying, the mixture was passed through an 80-mesh sieve. The mixed powder was pressed into blocks and kept at 950℃ in a muffle furnace for 4 hours. It was then ball-milled into powder and dried to obtain PZT-based piezoelectric ceramic matrix powder with a particle size of 0.5-1μm.

[0056] S2, the ceramic matrix powder is ball-milled with 0.5% (by weight) of LBPBSC for 24 hours, dried, and sieved to obtain low-temperature sintered PZT-based piezoelectric ceramic powder with a particle size <1μm; the ball milling process in steps S1 and S2 is as follows: deionized water is used as solvent, zirconia balls are used as ball milling media, the mass ratio of material, balls and water is 1:1.5:1, and the ball milling speed is 100r / min;

[0057] S3, anhydrous ethanol and butanone were mixed in a mass ratio of 7:3 as a solvent (96g added), triethyl phosphate (7g) as a dispersant, polyvinyl butyral (PVB) (20g) and phthalate (3g) as binders, and low-temperature sintered PZT-based piezoelectric ceramic powder (100g) to prepare a slurry. After defoaming, the slurry was cast into a ceramic film. The inner electrode silver paste was brushed onto the ceramic film, and then stacked to form a green body. The temperature was raised to 600℃ at a rate of 1℃ / min and held for 2h to remove the binder. Then, it was sintered at 850℃ for 4h. The sintered stacked ceramic was polished, the outer electrode silver paste was brushed on, and after calcination at 650℃ for 0.5h, it was polarized in silicone oil at 120℃ with a polarization electric field strength of 3kV / mm and a polarization time of 30min. After cleaning and aging for 24h, the stacked actuator was obtained.

[0058] The prepared stacked actuator was polished, and SEM images and EDS elemental distribution maps of the cross-section of the stacked actuator were obtained, such as... Figure 3 As shown, the boundary between the piezoelectric ceramic layer and the inner electrode layer is obvious, the thickness between layers is relatively uniform, and the overall structure is quite regular without any defects such as delamination. The grain size in the ceramic layer is uniform, the microstructure is relatively dense, and there are no large number of closed pores. This result indicates that the multilayer piezoelectric ceramic actuator is well sintered at 850℃. In addition, Figure (e) also shows that the inner electrode layer has strong continuity, and Ag element is concentrated in the electrode layer without significant diffusion into the ceramic layer. This indicates that the stacked actuator has a complete structure and good conductivity, verifying that the low-temperature sintered PZT-based piezoelectric ceramic material of this invention can meet the application requirements of multilayer stacked piezoelectric ceramic devices.

[0059] Example 2

[0060] The chemical composition of the low-temperature sintered PZT-based piezoelectric ceramic material in this embodiment is as follows:

[0061] 0.38Pb(Mg 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 O3 + 0.55% LBPBSC

[0062] LBPBSC is a nano-sized PbO-B2O3-SiO2-Li2O-Bi2O3-CuO glass powder. The molar ratio of PbO, B2O3, SiO2, Li2O, Bi2O3, and CuO in LBPBSC is 37:12:6:12:11:7. The preparation method of LBPBSC includes the following steps:

[0063] 1) Dissolve lithium acetate, bismuth acetate, copper acetate, lead acetate, boric acid, and silicon acetate in anhydrous ethanol and stir with a magnetic stirrer at 40°C for 2 hours to form a sol.

[0064] 2) Mix and stir the sols of each group to form a mixed sol, and dry it at 60°C to obtain a dry gel;

[0065] 3) The dried gel was heat-treated in a muffle furnace at 450°C to obtain LBPBSC with a particle size of 230 nm. The preparation method of the low-temperature sintered PZT-based piezoelectric ceramic material in this embodiment includes the following steps:

[0066] S1, based on chemical composition 0.38Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 PbO, MgO, Nb2O5, ZrO2 and TiO2 were weighed and ball-milled for 36 hours. After drying, the mixture was passed through a 90-mesh sieve. The mixed powder was pressed into blocks and kept at 900℃ in a muffle furnace for 2 hours. It was then ball-milled into powder and dried to obtain PZT-based piezoelectric ceramic matrix powder with a particle size of 0.5-1μm.

[0067] S2, the ceramic matrix powder and 0.55% (by mass) of LBPBSC were ball-milled for 36 hours, dried, and sieved to obtain low-temperature sintered PZT-based piezoelectric ceramic powder with a particle size <1μm; the ball milling process in steps S1 and S2 was as follows: deionized water was used as the solvent, zirconia balls were used as the ball milling medium, the mass ratio of material, balls and water was 1:1.5:1, and the ball milling speed was 100r / min;

[0068] S3. A 10% PVA solution was added to the low-temperature sintered PZT-based piezoelectric ceramic powder. The amount of PVA solution added was 0.4% of the mass of the low-temperature sintered PZT-based piezoelectric ceramic powder. The powder was granulated and then pressed into ceramic sheets with a diameter of 19 mm and a thickness of 1 mm. The ceramic sheets were heated to 550 °C at a rate of 1.5 °C / min and held for 3 h to remove the binder. Then, they were sintered at 875 °C for 2 h to form ceramic. The sintered ceramic was polished, coated with silver paste, calcined at 700 °C for 0.75 h, and then polarized in silicone oil at 130 °C with a polarization electric field strength of 3.2 kV / mm and a polarization time of 20 min. After cleaning and aging for 24 h, the low-temperature sintered PZT-based piezoelectric ceramic material was obtained.

[0069] Example 3

[0070] The chemical composition of the low-temperature sintered PZT-based piezoelectric ceramic material in this embodiment is as follows:

[0071] 0.38Pb(Mg 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 O3 + 0.6% LBPBSC

[0072] LBPBSC is a nano-sized PbO-B2O3-SiO2-Li2O-Bi2O3-CuO glass powder. The molar ratio of PbO, B2O3, SiO2, Li2O, Bi2O3, and CuO in LBPBSC is 40:15:8:15:12:10. The preparation method of LBPBSC includes the following steps:

[0073] 1) Dissolve lithium acetate, bismuth acetate, copper acetate, lead acetate, boric acid, and silicon acetate in anhydrous ethanol, and stir with a magnetic stirrer at 45°C for 3 hours to form a sol.

[0074] 2) Mix and stir the sols of each group to form a mixed sol, and dry it at 70°C to obtain a dry gel;

[0075] 3) The dried gel was heat-treated in a muffle furnace at 550°C to obtain LBPBSC with a particle size of 300 nm. The preparation method of the low-temperature sintered PZT-based piezoelectric ceramic material in this embodiment includes the following steps:

[0076] S1, based on chemical composition 0.38Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6PbO, MgO, Nb2O5, ZrO2 and TiO2 were weighed and ball-milled for 48 hours. After drying, the mixture was passed through a 100-mesh sieve. The mixed powder was pressed into blocks and kept at 925℃ in a muffle furnace for 3 hours. It was then ball-milled into powder and dried to obtain PZT-based piezoelectric ceramic matrix powder with a particle size of 0.5-1μm.

[0077] S2, the ceramic matrix powder and 0.6% (by mass) of LBPBSC were ball-milled for 24 hours, dried, and sieved to obtain low-temperature sintered PZT-based piezoelectric ceramic powder with a particle size <1μm; the ball milling process in steps S1 and S2 was as follows: deionized water was used as the solvent, zirconia balls were used as the ball milling medium, the mass ratio of material, balls and water was 1:1.5:1, and the ball milling speed was 100r / min;

[0078] S3. A 15% PVA solution was added to the low-temperature sintered PZT-based piezoelectric ceramic powder. The amount of PVA solution added was 0.5% of the mass of the low-temperature sintered PZT-based piezoelectric ceramic powder. The powder was granulated and then pressed into ceramic sheets with a diameter of 19 mm and a thickness of 1 mm. The ceramic sheets were heated to 500 °C at a rate of 2 °C / min and held for 4 h to remove the binder. Then, they were sintered at 850 °C for 3 h to form ceramic. The sintered ceramic was polished, coated with silver paste, calcined at 730 °C for 1 h, and then polarized in silicone oil at 140 °C with a polarization electric field strength of 3.5 kV / mm and a polarization time of 25 min. After cleaning and aging for 24 h, the low-temperature sintered PZT-based piezoelectric ceramic material was obtained.

[0079] Comparative Example 1

[0080] The only difference between Comparative Example 1 and Example 1 is that a = 0.4.

[0081] Comparative Example 2

[0082] The only difference between Comparative Example 2 and Example 1 is that a = 0.7.

[0083] Comparative Example 3

[0084] The only difference between Comparative Example 3 and Example 1 is that LBPBSC is replaced with a sintering aid made by directly mixing PbO, B2O3, SiO2, Li2O, Bi2O3, and CuO in a molar ratio of 35:10:5:10:10:5, and the particle size of the sintering aid is 200 nanometers.

[0085] Comparative Example 4

[0086] The only difference between Comparative Example 4 and Example 1 is that LBPBSC does not contain PbO, while the molar ratios of other components remain unchanged.

[0087] The performance of the low-temperature sintered PZT-based piezoelectric ceramic materials prepared in each embodiment and comparative example was tested.

[0088] ρ is the bulk density, which is measured using the Archimedes' method of displacement.

[0089] d 33 Let be the piezoelectric constant, and its formula is:

[0090]

[0091] In the formula, F3 represents the stress applied in the polarization direction; Q3 represents the electric displacement generated on the electrode surface; d 33 The piezoelectric constant is denoted by , where the first 3 in the subscript indicates the polarization direction and the second 3 indicates the stress direction. This invention uses quasi-static d... 33 The piezoelectric constant was measured using a tester (ZJ-4AN, Institute of Acoustics, Chinese Academy of Sciences).

[0092] ε r Let be the relative permittivity, and its formula is:

[0093]

[0094] In the formula, C represents the capacitance of the ceramic sample, in F; t represents the thickness of the ceramic sample, in m; and A represents the effective area of ​​the electrode, in m². 2 ε0 represents the vacuum permittivity, ε0 ​​= 8.854 × 10⁻⁶. -12 (F / m).

[0095] Q m The mechanical quality factor is given by the following formula:

[0096]

[0097] In the formula, C0 represents the static capacitance of the piezoelectric material; C1 represents the equivalent capacitance of the piezoelectric material; C0 + C1 is approximately equal to the capacitance of the piezoelectric material measured at 1 kHz; R1 represents the minimum impedance at resonance; Δf = f a -f r All parameters were measured using an impedance analyzer (1260A+1296A, Solartron Analytical, UK).

[0098] K p The planar electromechanical coupling coefficient is given by the following formula:

[0099]

[0100] In the formula, f r f is the resonant frequency; aThis is the anti-resonant frequency. To ensure the accuracy of the test results, the diameter / thickness of the test sample in this invention is greater than 10. All the above parameters were measured using an impedance analyzer (1260A+1296A, Solartron Analytical, UK).

[0101] tanδ represents dielectric loss, and its formula is:

[0102]

[0103] In the formula, I R Indicates the portion of the current consumed by the dielectric material; I C The capacitance is represented by ω, where ω represents the angular frequency of the alternating electric field, C represents the capacitance of the ceramic sample, and R represents the loss resistance. The dielectric constant and dielectric loss of the material were measured using an impedance analyzer (1260A+1296A, Solartron Analytical, UK) at a frequency of 1kHz.

[0104] P r To determine the residual polarization intensity, this invention employs an RTI-Multiferroic ferroelectric testing instrument (Radiant Technologies, USA) and a Sawyer-Tower circuit to test the ferroelectric properties of piezoelectric ceramics, obtaining the hysteresis loop (PE curve). The test frequency is 1 Hz, and the test electric field is 30 kV / cm. To prevent sample edge and air breakdown during the test, the ceramic sample is completely immersed in high-boiling-point silicone oil.

[0105] T c The Curie temperature is obtained by using a broadband dielectric spectrum analyzer (Novocontrol concept 80) to test the dielectric constant at different temperatures.

[0106] Table 1

[0107]

[0108] As can be seen from Table 1, Examples 1-3 have high density and piezoelectric properties. Comparative Examples 1 and 2 use the same sintering aids as the examples, but the amount used exceeds the reference value. Comparative Example 1 uses less than the reference value. The liquid phase formed directly or indirectly between the sintering aid and the matrix powder during the sintering process cannot fully wet the powder particles, and the ceramic cannot be completely densified. Comparative Example 2 uses more than the reference value. Excessive liquid phase will segregate at the grain boundaries, forming a second impurity. Therefore, although the ceramic has extremely high density, its piezoelectric properties are poor. The sintering aids used in Comparative Examples 3 and 4 are too different from those in the examples, and the desired results cannot be obtained in terms of density and piezoelectric properties.

[0109] The above embodiments are merely examples for clear illustration and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations, and any obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A low-temperature sintered PZT-based piezoelectric ceramic material, characterized in that, Its chemical composition is 0.38Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 The compound is LBPBSC with a content of 0.38Pb(MgO) + a%, where LBPBSC is nano-sized PbO-B2O3-SiO2-Li2O-Bi2O3-CuO glass powder. The molar ratio of PbO, B2O3, SiO2, Li2O, Bi2O3, and CuO in LBPBSC is (35~40):(10~15):(5~8):(10~15):(10~12):(5~10). The mass of LBPBSC is 0.38Pb(MgO) + a%. 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 a% of the mass of O3, where 0.5 ≤ a ≤ 0.6; The preparation method of the LBPBSC includes the following steps: 1) Dissolve lithium acetate, bismuth acetate, copper acetate, lead acetate, boric acid, and silicon acetate in anhydrous ethanol, heat to 40-50°C and stir for 1-3 hours to form a sol. 2) Mix and stir the sols of each group to form a mixed sol, and dry at 60~80℃ to obtain a dry gel; 3) The dry gel was heat-treated in a muffle furnace at 450~550℃ to obtain LBPBSC with a particle size of 200~300nm.

2. A method for preparing a low-temperature sintered PZT-based piezoelectric ceramic material as described in claim 1, characterized in that, Includes the following steps: S1, based on chemical composition 0.38Pb(Mg) 1 / 3 Nb 2 / 3 O3-0.62Pb(Zr) 0.4 Ti 0.6 PbO, MgO, Nb2O5, ZrO2 and TiO2 were weighed, ball-milled and mixed evenly, dried and sieved. The mixed powder was pressed into blocks, pre-fired in a muffle furnace, ball-milled into powder, and dried to obtain PZT-based piezoelectric ceramic matrix powder. S2, the ceramic matrix powder is ball-milled and mixed with LBPBSC, dried and sieved to obtain low-temperature sintered PZT-based piezoelectric ceramic powder; S3 involves adding a binder to low-temperature sintered PZT-based piezoelectric ceramic powder, forming it, removing the binder, sintering it, polishing the sintered ceramic, coating it with silver paste, and then calcining and polarizing it to obtain low-temperature sintered PZT-based piezoelectric ceramic material.

3. The method for preparing low-temperature sintered PZT-based piezoelectric ceramic materials according to claim 2, characterized in that, The sintering temperature is 850~900℃, and the sintering time is 2~4h.

4. The method for preparing low-temperature sintered PZT-based piezoelectric ceramic materials according to claim 2, characterized in that, In step S1, the ball milling mixing time is 24~48h, and the sieving is through an 80~100 mesh sieve; the pre-firing temperature is 900~950℃, and the pre-firing time is 2~4h; the particle size of the PZT-based piezoelectric ceramic matrix powder is 0.5~1μm.

5. The method for preparing low-temperature sintered PZT-based piezoelectric ceramic materials according to claim 2, characterized in that, In step S2, the ball milling mixing time is 24~48h; the particle size of the low-temperature sintered PZT-based piezoelectric ceramic powder is <1μm.

6. The method for preparing low-temperature sintered PZT-based piezoelectric ceramic materials according to claim 2, characterized in that, The binder is a PVA solution with a mass fraction of 5-15%, and the amount of binder added is 0.3-0.5% of the mass of the low-temperature sintered PZT-based piezoelectric ceramic powder; the molding process involves granulation followed by pressing, with a pressing pressure of 10-20 MPa.

7. The method for preparing low-temperature sintered PZT-based piezoelectric ceramic materials according to claim 2, characterized in that, The adhesive removal temperature is 500~600℃, the heating rate is 1~2℃ / min, and the adhesive removal time is 2~4h; the calcination temperature is 650~730℃, and the calcination time is 0.5~1h; the polarization is carried out in silicone oil at 120~140℃, the polarization electric field strength is 3~3.5kV / mm, and the polarization time is 20~30min.

8. The application of the low-temperature sintered PZT-based piezoelectric ceramic material as described in claim 1 in the preparation of piezoelectric ceramic components.

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