A lead zirconate titanate-lead niobate piezoelectric ceramic material with high curie temperature and high Young's modulus, a preparation method and application thereof

Abstract

The application relates to a lead zirconate titanate-lead niobate piezoelectric ceramic material with high Curie temperature and high Young's modulus, a preparation method and application thereof. The low-temperature sintering lead zirconate titanate-lead niobate piezoelectric ceramic material has a chemical composition of 0.3Pb(Ni 1 / 3Nb 2 / 3 )O3-xPbZrO3-(0.7-x)PbTiO3+1.8mol% LiNbO3+2mol% Li2CO3, wherein 0.300<=x<=0.320. The application adds appropriate amounts of LiNbO3 and Li2CO3, adjusts the contents of zirconium and titanium, optimizes the components of the system morphotropic phase boundary rhombohedral phase and tetragonal phase, improves piezoelectric performance and mechanical performance, realizes low-temperature sintering, and provides a new solution for realizing high-performance and high-reliability piezoelectric ceramic laminated drivers.

Description

Technical Field

[0001] This invention belongs to the field of piezoelectric ceramic multilayer actuators, and relates to a low-temperature sintered piezoelectric ceramic material for piezoelectric ceramic multilayer actuators. Specifically, it relates to a low-temperature sintered lead niobate nickel-lead zirconate titanate piezoelectric ceramic material with both high Curie temperature and high Young's modulus, a piezoelectric ceramic element and its preparation method. Background Technology

[0002] Piezoelectric ceramic multilayer actuators, due to their small size, fast response, and large output torque, compensate for the shortcomings of traditional electromagnetic drives in high-precision motion and positioning control, and are widely used in instruments and equipment such as semiconductor manufacturing, micro-precision cutting machines, laser positioners, and micro-precision valves. In recent years, with the rapid development of the aerospace and defense industries, piezoelectric ceramic multilayer actuators are increasingly being used in extreme environments with wide temperature ranges, strong vibrations, and high overloads, requiring piezoelectric ceramics to possess both excellent piezoelectric and mechanical properties. However, increasing the Curie temperature often leads to a decrease in piezoelectric performance, which severely limits the application of piezoelectric ceramic actuators. On the other hand, Young's modulus plays a crucial role in determining mechanical behavior, and piezoelectric ceramics with high Young's modulus urgently need further development.

[0003] Piezoelectric ceramic multilayer actuators are generally co-fired by stacking lead zirconate titanate piezoelectric ceramic layers and metal (Pt or Ag-Pd) inner electrodes. Compared to Pt electrodes, Ag-Pd silver-palladium electrodes are not only lower in cost but also have better solderability and processing performance, simplifying the manufacturing process and reducing production costs. Compatibility with Ag-Pd electrodes requires the sintering temperature of the co-fired ceramic to not exceed 1150℃. Low-temperature sintering can also effectively suppress the volatilization of PbO, which can lead to stoichiometric shifts and performance degradation. Therefore, developing low-temperature sintered piezoelectric ceramics is an important research direction for developing high-reliability, high-electrical-performance, and low-cost piezoelectric ceramic multilayer actuators. Summary of the Invention

[0004] To address the aforementioned problems, this invention presents a low-temperature sintered lead nickel niobate-lead zirconate titanate (PNN-PZT) piezoelectric ceramic material, piezoelectric ceramic element, and preparation method thereof, which possess both high Curie temperature and high Young's modulus. This invention achieves the preparation of high-performance low-temperature (not exceeding 1120℃) sintered lead nickel niobate-lead zirconate titanate piezoelectric ceramics by adding appropriate amounts of lithium carbonate and lithium niobate.

[0005] In a first aspect, the present invention provides a lead nickel niobate-lead zirconate titanate piezoelectric ceramic material with both high Curie temperature and high Young's modulus, wherein the chemical composition of the lead nickel niobate-lead zirconate titanate piezoelectric ceramic material is: 0.3Pb(Ni 1 / 3 Nb 2 / 3The formula is: (0.7-x)PbTiO3 + 1.8 mol% LiNbO3 + 2 mol% Li2CO3, where 0.300 ≤ x ≤ 0.320. The lead nickel niobate-lead zirconate titanate piezoelectric ceramic material exhibits a phase structure characterized by the coexistence of trigonal and tetragonal phases. LiNbO3 and Li2CO3 are added during the initial mixing of the raw materials, reducing the sintering temperature to 1000℃ to 1120℃.

[0006] In this invention, the piezoelectric properties of PNN-PZT are improved by selecting an appropriate amount of LiNbO3. A certain amount of Li2CO3 is added using a one-step method, and the composition of the trigonal and tetragonal phases at the quasi-isomorphic phase boundary of the system is optimized by adjusting the content of zirconium and titanium. This improves the piezoelectric and mechanical properties while achieving low-temperature sintering, resulting in a high-performance PNN-PZT-LiNbO3+Li2CO3 piezoelectric ceramic material.

[0007] Preferably, the piezoelectric constant of the lead nickel niobate-lead zirconate titanate piezoelectric ceramic material is 517-607 pC / N;

[0008] The lead nickel niobate-lead zirconate titanate piezoelectric ceramic material has a relative permittivity of 2706–3520 and a dielectric loss of 1.5%–2.0% at room temperature and a frequency of 1 kHz.

[0009] The Curie temperature of the lead nickel niobate-lead zirconate titanate piezoelectric ceramic material is 220-229℃.

[0010] The Young's modulus of the lead nickel niobate-lead zirconate titanate piezoelectric ceramic material is 165–176 GPa (1.65 × 10⁻⁶). 11 ~1.76×10 11 N / m 2 ).

[0011] Secondly, the present invention provides a method for preparing the above-mentioned lead nickel niobate-lead zirconate titanate piezoelectric ceramic material, comprising:

[0012] (1) Using PbO or Pb3O4, ZrO2, TiO2, Ni2O3 or NiO, Nb2O5 and Li2CO3 as raw materials, weigh the raw materials according to the chemical composition of lead nickel niobate-lead zirconate titanate piezoelectric ceramic materials and mix them. After pre-firing, ceramic powder is obtained.

[0013] (2) The obtained ceramic powder is finely ground and pressed into shape to obtain a ceramic blank;

[0014] (3) The obtained ceramic blank is sintered to obtain the low-temperature sintered lead nickel niobate-lead zirconate titanate piezoelectric ceramic material.

[0015] Preferably, in step (1), the mixing method is wet ball milling, and the parameters of wet ball milling include: the mass ratio of raw material powder: ball milling medium: solvent is 1:(3.0~5.0):(0.8~1.5), and the ball milling time is 4~24 hours.

[0016] Preferably, in step (1), the temperature of the pre-firing treatment is 700-800°C, the time is 2-4 hours, and the heating rate is 2-5°C / minute.

[0017] Preferably, in step (2), the fine grinding method is wet ball milling, and the parameters of wet ball milling include: the mass ratio of ceramic powder: ball milling medium: solvent is 1:(3.0~5.0):(0.8~1.5), and the ball milling time is 4~24 hours.

[0018] Preferably, in step (2), before pressing and molding, the finely ground ceramic powder is mixed with a binder for granulation, and then aged and sieved; the amount of binder added is 4 to 8 wt.% of the ceramic powder; the aging time is 22 to 26 hours.

[0019] Preferably, in step (3), the sintering temperature is 1000-1120°C, the time is 2-4 hours, and the heating rate is 2-5°C / minute.

[0020] Preferably, in step (3), before sintering, the ceramic blank is debonded in the air; the debonding temperature is 550-700°C and the time is 2-4 hours.

[0021] Preferably, silver electrodes are prepared on the upper and lower surfaces of the obtained lead nickel niobate-lead zirconate titanate piezoelectric ceramic material, and then polarization treatment is performed.

[0022] The parameters of the polarization treatment include: the polarization field strength is 3-4 kV / mm; the polarization temperature is 80-120℃; and the polarization time is 10-30 minutes.

[0023] Thirdly, the present invention provides an application of the above-mentioned lead nickel niobate-lead zirconate titanate piezoelectric ceramic material in a piezoelectric ceramic stack actuator.

[0024] Beneficial effects:

[0025] (1) In this invention, the obtained PNN-PZT+LiNbO3+Li2CO3 piezoelectric ceramic material has a low sintering temperature (1000~1120℃), a high piezoelectric constant (517~607pC / N), a high Curie temperature (220~229℃), and a high Young's modulus (165~176GPa). The PNN-PZT+LiNbO3+Li2CO3 piezoelectric ceramic material prepared in this invention has a trigonal-tetragonal phase coexistence at room temperature, that is, all components are at the quasi-isomorphic phase boundary.

[0026] (2) Normally, as the piezoelectric properties increase, the Curie temperature decreases significantly. However, by adding LiNbO3 and Li2CO3 to the ceramic powder, the present invention can effectively reduce the sintering temperature and maintain the piezoelectric properties of the ceramic material while still achieving a Curie temperature of over 220°C.

[0027] (3) Compared with traditional PZT-5 series piezoelectric ceramics (100-130 GPa), the low-temperature sintered high-performance ceramics (165-176 GPa) prepared in this invention exhibit a higher Young's modulus. This characteristic is of great significance for the application of piezoelectric ceramic stacked actuators in extreme environments. This invention provides a new solution for realizing high-performance and high-reliability piezoelectric ceramic stacked actuators. Attached Figure Description

[0028] Figure 1 The lead nickel niobate-lead zirconate titanate (0.3Pb(Ni)) obtained in this invention 1 / 3 Nb 2 / 3 X-ray diffraction pattern of piezoelectric ceramic material powder: (a) is the XRD pattern in the range of 10° to 80° at room temperature, and (b) is the Bragg peak near 45°.

[0029] Figure 2 The lead nickel niobate-lead zirconate titanate (0.3Pb(Ni)) obtained in this invention 1 / 3 Nb 2 / 3 )O3-xPbZrO3-(0.7-x)PbTiO3+1.8mol%LiNbO3+2mol%Li2CO3, where 0.300≤x≤0.320) is the piezoelectric constant value of piezoelectric ceramic materials;

[0030] Figure 3 The lead nickel niobate-lead zirconate titanate (0.3Pb(Ni)) obtained in this invention 1 / 3 Nb 2 / 3The Young's modulus of the piezoelectric ceramic material is calculated by testing the resonance method. (0.7-x)PbTiO3 + 1.8 mol% LiNbO3 + 2 mol% Li2CO3, where 0.300 ≤ x ≤ 0.320. );

[0031] Figure 4 The lead nickel niobate-lead zirconate titanate (0.3Pb(Ni)) obtained in this invention 1 / 3 Nb 2 / 3 Dielectric temperature spectrum of piezoelectric ceramic materials from 30℃ to 250℃: 0.300 ≤ x ≤ 0.320 )O3-xPbZrO3-(0.7-x)PbTiO3+1.8mol%LiNbO3+2mol%Li2CO3;

[0032] Figure 5 The lead nickel niobate-lead zirconate titanate (0.3Pb(Ni)) obtained in this invention 1 / 3 Nb 2 / 3 The unipolar strain hysteresis loop (SE) curve and corresponding equivalent piezoelectric constant d of the piezoelectric ceramic element are given by: O3-xPbZrO3-(0.7-x)PbTiO3+1.8mol%LiNbO3+2mol%Li2CO3, where 0.300≤x≤0.320. 33 * Calculated value ( Equivalent piezoelectric constant (Determined by the maximum strain value under the maximum electric field);

[0033] Figure 6 (a) is the X-ray diffraction pattern of the lead nickel niobate-lead zirconate titanate (without LiNbO3) piezoelectric ceramic material powder obtained in Comparative Example 1; Figure 6 (b) is a SEM image of the surface of the lead nickel niobate-lead zirconate titanate (without LiNbO3) piezoelectric ceramic material obtained in Comparative Example 1. Figure 6 (c) Dielectric temperature spectrum test of the piezoelectric ceramic element obtained in Comparative Example 1 from 30°C to 300°C; Figure 6 (d) is a comparison chart of the performance test data (piezoelectric constant, density, planar electromechanical coupling coefficient, mechanical quality factor, and Young's modulus) of the piezoelectric ceramic elements obtained in Comparative Example 1 and Experimental Example 12. Detailed Implementation

[0034] To further illustrate the invention's content, features, and practical effects, the invention will be described in detail below with reference to embodiments. It should be noted that the modification methods of the invention are not limited to these specific implementation methods. Equivalent substitutions and modifications made by those skilled in the art based on their reading of the invention's content, without departing from the spirit and essence of the invention, are also within the scope of protection claimed by this invention.

[0035] In this disclosure, the composition of the low-temperature sintered high-performance piezoelectric ceramic material is: 0.3Pb(Ni 1 / 3 Nb 2 / 3 The composition is: O3-xPbZrO3-(0.7-x)PbTiO3+1.8mol%LiNbO3+2mol%Li2CO3, where 0.300≤x≤0.320. According to the phase diagram analysis of the PNN-PZT ternary system, when x<0.300, the material composition deviates from the quasi-isomorphic phase boundary (MPB) region. This compositional shift causes an imbalance in the ratio of trigonal and tetragonal phases in the material, weakening the unique polarization rotation mechanism near the phase boundary, thereby reducing the domain flipping response capability under external field excitation, resulting in a significant decrease in piezoelectric performance, making it difficult to meet the application requirements of piezoelectric ceramic multilayer actuators for aerospace. The sintering temperature of this low-temperature sintering material is 1000~1120℃. At room temperature (~25℃), trigonal and tetragonal phases coexist. This series of materials has a high Curie temperature of 220~229℃ and a very high Young's modulus of 165~176GPa.

[0036] The aerospace industry faces extreme operating conditions such as wide temperature ranges and strong vibrations, requiring piezoelectric ceramic multilayer actuators to possess large strain, high stiffness, and high Curie temperature. The key scientific challenge lies in overcoming the inverse correlation between piezoelectric coefficient and Curie temperature, as well as the mutual constraints between piezoelectric and mechanical properties. This invention achieves comprehensive optimization of piezoelectric ceramic material properties through an innovative scheme of precisely controlling the zirconium / titanium ratio (Zr / Ti) and synergistically adding LiNbO3 and Li2CO3.

[0037] In this invention, the material properties are comprehensively optimized by precisely controlling the zirconium-titanium ratio (Zr / Ti). At the crystal structure level, the adjustment of the zirconium-titanium ratio directly determines the occupancy of B-site ions in the ABO3 structure of the perovskite. 4+ and Ti 4+ The synergistic effect of these phases leads to a crystal structure situated at the phase boundary between the trigonal (R3m) and tetragonal (P4mm) phases. This quasi-isomorphic phase boundary (MPB) state significantly enhances the material's polarization response. In defect engineering, precise control of the zirconium-titanium ratio provides an ideal matrix environment for LiNbO3 doping. When the Zr content is moderately increased, the larger Zr content... 4+ ion The lattice expansion effect generated at the B site can effectively compensate for the Li + Replace A-position Pb 2+ The lattice contraction caused by this strain balance significantly reduces the lattice distortion energy, thereby lowering the formation energy of defect dipoles. In terms of domain structure control, MPB promotes the formation of uniformly sized domain structures. Piezoelectric microscopy (PFM) observations show that this domain structure facilitates rapid domain flipping under an external electric field (enhancing piezoelectric response) and also suppresses mechanical property degradation through domain wall pinning effects.

[0038] In this invention, the material properties are further improved by designing a Li-Nb donor-acceptor co-doping strategy, constructing a [Li'Pb-Nb·Ti / Zr] defect dipole network in a 0.3PNN-0.7PZT matrix: on the one hand, Li + As a donor dopant, Nb lowers the domain wall energy barrier, increasing domain wall mobility and thus leading to increased strain; on the other hand, Nb... 5+ As acceptor doping generates a localized stress field, domain wall stability is maintained through a pinning effect, increasing the Young's modulus to 176 GPa. This defect engineering allows the material to maintain piezoelectric activity (d) at a high Curie temperature of 227 °C. 33 =605pC / N), successfully solved the key technical bottleneck of the traditional material's inability to simultaneously achieve "high voltage electrical properties, high mechanical strength, and high Curie temperature", and provided an ideal solution for high-reliability actuators for aerospace applications.

[0039] The following exemplarily illustrates the preparation method of the lead nickel niobate-lead zirconate titanate-piezoelectric ceramic material with both high Curie temperature and high Young's modulus provided by the present invention.

[0040] Using PbO (or Pb3O4), ZrO2, TiO2, Ni2O3 or NiO, Nb2O5 and Li2CO3 as raw materials, according to the chemical formula 0.3Pb(Ni 1 / 3 Nb 2 / 3 The stoichiometric ratio of (0.7-x)PbTiO3 + 1.8 mol% LiNbO3 + 2 mol% Li2CO3 is used to prepare and mix the powder to obtain a mixed powder. For example, wet ball milling is used for mixing, followed by drying. In the wet ball milling, the ceramic powder: milling media: solvent is mixed for 4 to 24 hours according to a mass ratio of 1:(3.0~5.0):(0.8~1.5), wherein the milling media are stainless steel balls, zirconium balls, or agate balls, and the solvent is anhydrous ethanol or deionized water.

[0041] The mixed powder is pre-fired to obtain ceramic powder. The pre-firing conditions include: holding at 700–800°C in air for 2–4 hours. The heating rate during pre-firing is less than 5°C / min. Preferably, the ceramic powder is briquetted before pre-firing to obtain the final ceramic powder.

[0042] Ceramic powder is directly pressed into shape (sheets or blocks) to obtain a ceramic green body. Preferably, a binder is added to the ceramic powder to granulate it (this step yields granulated ceramic powder), which is then aged, pressed into shape, and then debinded to obtain the ceramic green body.

[0043] In an optional embodiment, before pressing and molding, the ceramic powder is finely ground using a wet ball milling method and then dried to achieve a finer particle size. The fine grinding is performed at a mass ratio of ceramic powder:milling media:solvent = 1:(3.0–5.0):(0.8–1.5) to ensure a finer particle size and narrower particle distribution. The milling media are steel balls, zirconium balls, or agate balls, and the solvent is anhydrous ethanol or deionized water. The wet ball milling time is 4–24 hours, and the ceramic powder is obtained after fine grinding and drying.

[0044] In an optional embodiment, the binder may be polyvinyl alcohol (PVA) or the like. The amount of binder added may be 4-8 wt.% of the weight of the ceramic powder (or granulated ceramic powder). The aging time may be 22-26 hours. The conditions for debinding are: holding at 550-700°C in an oxygen atmosphere for 2-4 hours.

[0045] The ceramic blank is placed in a high-temperature furnace and sintered to obtain the piezoelectric ceramic material.

[0046] In an optional embodiment, the sintering conditions include: heating to 1000–1120°C in air at a heating rate of less than 5°C / min, holding at that temperature for 2–4 hours, and then cooling in the furnace.

[0047] The piezoelectric ceramic element provided by this invention is prepared from the above-mentioned piezoelectric ceramic material. The preparation method of the piezoelectric ceramic element includes: processing the sintered piezoelectric ceramic material into the required size, preparing electrodes, and then performing polarization treatment to obtain the piezoelectric ceramic element.

[0048] In an optional embodiment, the electrode is prepared by coating both sides of the obtained piezoelectric ceramic material with silver, then heating it to 700–850°C at a rate of 1–3°C / min and holding it at that temperature for 10–30 minutes to perform silver firing. The parameters of the polarization treatment include: a polarization field strength of 3–4 kV / mm; a polarization temperature of 80–120°C; and a polarization time of 10–30 minutes.

[0049] In an optional embodiment, the resulting piezoelectric ceramic element has a high piezoelectric constant at room temperature, preferably ~605 pC / N, a high Curie temperature, preferably ~227 °C, and a high Young's modulus, preferably ~176 GPa.

[0050] The following examples further illustrate the present invention in detail. It should also be understood that the following examples are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values ​​in the examples below.

[0051] Example 1

[0052] In Example 1, lead nickel niobate-lead zirconate titanate (0.3Pb(Ni 1 / 3 Nb 2 / 3 The preparation process of piezoelectric ceramic materials includes: O3-0.300PbZrO3-0.400PbTiO3+1.8mol%LiNbO3+2mol%Li2CO3 (x=0.300)

[0053] (1) Weigh the raw material powder Pb3O4 or PbO, ZrO2, TiO2, Ni2O3 or NiO, Nb2O5 and Li2CO3 according to the above chemical formula composition, mix them by wet ball milling, and after mixing for 10 hours according to the mass ratio of raw material powder: ball milling media: anhydrous ethanol = 1:3.0:0.8, dry and press into blocks, and pre-fire at 750°C at a heating rate of 3°C / min in air atmosphere for 2 hours to obtain ceramic powder;

[0054] (2) The obtained ceramic powder is crushed, then finely ground by wet ball milling for 8 hours and dried. Then, 6wt.% PVA binder of powder weight is added, granulated, aged for 24 hours, passed through an 80-mesh sieve, pressed into a circular sheet with a diameter of 13mm and a thickness of 2mm, and then the binder is removed by heating to 650℃ in the air for 2 hours to obtain a ceramic body.

[0055] (3) Place the ceramic blank into an alumina crucible, cover it with a ground glass lid, and heat it to 1000°C in air at a heating rate of 3°C / min. Hold it at that temperature for 3 hours and then cool it in the furnace to obtain lead nickel niobate-lead zirconate titanate ceramic material.

[0056] (4) Grind the obtained ceramic material into a ceramic sheet with a thickness of 1 mm, clean it, dry it, silver it, dry it, raise the temperature to 730°C at a heating rate of 3°C / min, keep it at the temperature for 30 minutes to fire silver, and obtain the ceramic element.

[0057] Example 2

[0058] In this Example 2, the preparation process of lead nickel niobate-lead zirconate titanate is the same as in Example 1, except that the sintering temperature in step (3) is 1050℃.

[0059] Example 3

[0060] The preparation process of lead nickel niobate-lead zirconate titanate in this Example 3 is the same as that in Example 1, except that the sintering temperature in step (3) is 1100℃.

[0061] Example 4

[0062] The preparation process of lead nickel niobate-lead zirconate titanate in this Example 4 is the same as that in Example 1, except that the sintering temperature in step (3) is 1120℃.

[0063] Example 5

[0064] In Example 5, the preparation process of lead nickel niobate-lead zirconate titanate is the same as in Example 1, except that the chemical composition of the lead nickel niobate-lead zirconate titanate piezoelectric ceramic material is: 0.3Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.305PbZrO3-0.395PbTiO3+1.8mol% LiNbO3+2mol% Li2CO3) (x=0.305).

[0065] Example 6

[0066] The preparation process of lead nickel niobate-lead zirconate titanate in this Example 6 is the same as that in Example 5, except that the sintering temperature in step (3) is 1050℃.

[0067] Example 7

[0068] The preparation process of lead nickel niobate-lead zirconate titanate in Example 7 is the same as that in Example 5, except that the sintering temperature in step (3) is 1100℃.

[0069] Example 8

[0070] The preparation process of lead nickel niobate-lead zirconate titanate in this Example 8 is the same as that in Example 5, except that the sintering temperature in step (3) is 1120℃.

[0071] Example 9

[0072] In Example 9, the preparation process of lead nickel niobate-lead zirconate titanate is the same as in Example 1, except that the chemical composition of the lead nickel niobate-lead zirconate titanate piezoelectric ceramic material is: 0.3Pb(Ni 1 / 3 Nb 2 / 3)O3-0.310PbZrO3-0.390PbTiO3+1.8mol% LiNbO3+2mol% Li2CO3) (x=0.310).

[0073] Example 10

[0074] The preparation process of lead nickel niobate-lead zirconate titanate in this Example 10 is the same as that in Example 9, except that the sintering temperature in step (3) is 1050℃.

[0075] Example 11

[0076] The preparation process of lead nickel niobate-lead zirconate titanate in this Example 11 is the same as that in Example 9, except that the sintering temperature in step (3) is 1100℃.

[0077] Example 12

[0078] The preparation process of lead nickel niobate-lead zirconate titanate in this Example 12 is the same as that in Example 9, except that the sintering temperature in step (3) is 1120℃.

[0079] Example 13

[0080] In Example 13, the preparation process of lead nickel niobate-lead zirconate titanate is the same as in Example 1, except that the chemical composition of the lead nickel niobate-lead zirconate titanate piezoelectric ceramic material is: 0.3Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.315PbZrO3-0.385PbTiO3+1.8mol% LiNbO3+2mol% Li2CO3) (x=0.315).

[0081] Example 14

[0082] The preparation process of lead nickel niobate-lead zirconate titanate in this Example 14 is the same as that in Example 13, except that the sintering temperature in step (3) is 1050℃.

[0083] Example 15

[0084] The preparation process of lead nickel niobate-lead zirconate titanate in this Example 15 is the same as that in Example 13, except that the sintering temperature in step (3) is 1100℃.

[0085] Example 16

[0086] The preparation process of lead nickel niobate-lead zirconate titanate in this Example 16 is the same as that in Example 13, except that the sintering temperature in step (3) is 1120℃.

[0087] Example 17

[0088] In Example 17, the preparation process of lead nickel niobate-lead zirconate titanate is the same as in Example 1, except that the chemical composition of the lead nickel niobate-lead zirconate titanate piezoelectric ceramic material is: 0.3Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.320PbZrO3-0.380PbTiO3+1.8mol% LiNbO3+2mol% Li2CO3) (x=0.320).

[0089] Example 18

[0090] The preparation process of lead nickel niobate-lead zirconate titanate in this Example 18 is the same as that in Example 17, except that the sintering temperature in step (3) is 1050℃.

[0091] Example 19

[0092] The preparation process of lead nickel niobate-lead zirconate titanate in this Example 19 is the same as that in Example 17, except that the sintering temperature in step (3) is 1100℃.

[0093] Example 20

[0094] The preparation process of lead nickel niobate-lead zirconate titanate in this Example 20 is the same as that in Example 17, except that the sintering temperature in step (3) is 1120℃.

[0095] Comparative Example 1

[0096] The preparation process of the lead nickel niobate-lead zirconate titanate piezoelectric ceramic material in Comparative Example 1 is the same as that in Example 12, except that LiNbO3 is not added.

[0097] Figure 1 The lead nickel niobate-lead zirconate titanate (0.3Pb(Ni)) obtained in this invention 1 / 3 Nb 2 / 3 X-ray diffraction spectra of piezoelectric ceramic material powders were obtained from the following: O3-xPbZrO3-(0.7-x)PbTiO3+1.8mol%LiNbO3+2mol%Li2CO3, where 0.300≤x≤0.320. As shown in the figure, all piezoelectric ceramic materials are perovskite pure phases, with no other second-phase impurities. Furthermore, the splitting of the (200) Bragg peak at 45° indicates that the piezoelectric ceramic materials simultaneously contain both trigonal and tetragonal phases, i.e., they are located in the quasi-isomorphic phase boundary region.

[0098] The lead nickel niobate-lead zirconate titanate (0.3Pb(Ni)) obtained in this invention 1 / 3 Nb 2 / 3The piezoelectric ceramic element was polarized at 120℃ and a DC electric field of 4kV / mm for 20 minutes and placed for more than 24 hours. The piezoelectric constant d of the piezoelectric ceramic element at room temperature was then measured. 33 (like Figure 2 As shown in the figure, the room temperature piezoelectric constant d increases with increasing PbZrO3 content. 33 The piezoelectric constant d at room temperature first increases and then decreases; when the PbZrO3 content is 0.315, the piezoelectric constant d at room temperature... 33 maximum.

[0099] The lead nickel niobate-lead zirconate titanate (0.3Pb(Ni)) obtained in this invention 1 / 3 Nb 2 / 3 The piezoelectric ceramic element was subjected to room temperature resonant frequency and density measurements, and Young's modulus was calculated. The reaction mixture consisted of O3-xPbZrO3-(0.7-x)PbTiO3+1.8mol%LiNbO3+2mol%Li2CO3, where 0.300≤x≤0.320. (like Figure 3 As shown in the figure, the Young's modulus first increases and then decreases with increasing PbZrO3 content. When the PbZrO3 content is 0.310, the Young's modulus is... maximum.

[0100] The lead nickelate-lead zirconate titanate (0.3Pb(Ni)) obtained in this invention 1 / 3 Nb 2 / 3 The dielectric temperature spectrum of the piezoelectric ceramic element from 30℃ to 250℃ was measured at a frequency of 1kHz. The results are as follows: (0.7-x)PbTiO3 + 1.8 mol% LiNbO3 + 2 mol% Li2CO3, where 0.300 ≤ x ≤ 0.320. Figure 4 As shown in the figure, the Curie temperature of the piezoelectric ceramic element is 220–229℃. The relative permittivity of the piezoelectric ceramic was tested according to the method specified in GB 11310-89 "Test Methods for Performance Characteristics of Piezoelectric Ceramic Materials: Relative Free Permittivity and Temperature Characteristics Test," and the dielectric loss of the piezoelectric ceramic was tested according to the method specified in GB / T 3389-2008 "Test Methods for Performance Parameters of Piezoelectric Ceramic Materials." At room temperature (~25℃) and a frequency of 1 kHz, the relative permittivity of the piezoelectric ceramic element is 2706–3520, and the dielectric loss is 1.5%–2.0%.

[0101] The lead nickel niobate-lead zirconate titanate (0.3Pb(Ni)) obtained in this invention 1 / 3 Nb2 / 3 The piezoelectric ceramic element was subjected to unipolar strain loop measurements at room temperature, and the equivalent piezoelectric constant d was calculated. The reaction mixture was: O3-xPbZrO3-(0.7-x)PbTiO3+1.8mol%LiNbO3+2mol%Li2CO3, where 0.300≤x≤0.320. 33 * (like Figure 5 As shown in the figure, with the increase of PbZrO3 content, the unipolar strain and the equivalent piezoelectric constant... The strain first increases and then decreases; when the PbZrO3 content is 0.310, the unipolar strain and the equivalent piezoelectric constant... maximum.

[0102] Figure 6 For comparative examples, lead nickel niobate-lead zirconate titanate (0.3Pb(Ni 1 / 3 Nb 2 / 3 The phase structure, microstructure, dielectric properties, and comparison with those of Experimental Example 12 of the model (O3-xPbZrO3-(0.7-x)PbTiO3+2mol%Li2CO3, where x=0.310) are described. Figure 6 (a) It can be seen that the lead nickelate-lead zirconate titanate piezoelectric ceramic material obtained in Comparative Example 1 has a phase composition that deviates from the quasi-isomorphic phase boundary (MPB) due to the lack of lithium niobate, and is a pure perovskite phase. Figure 6 (b) It can be seen that the particle size distribution on the surface of the lead nickelate-lead zirconate titanate piezoelectric ceramic material obtained in the comparative example exhibits obvious non-uniformity, with the grain size of the sample without lithium niobate increasing from 2.80 μm to 3.32 μm. Figure 6 (c) It can be seen that the Curie temperature of the piezoelectric ceramic element obtained in Comparative Example 1 is 234℃. From... Figure 6 (d) It can be seen that the piezoelectric coefficient and Young's modulus of the piezoelectric ceramic element obtained in Comparative Example 1 are significantly reduced. This phenomenon indicates that lithium ions and niobium ions need to work together to construct defect dipoles to enhance the piezoelectric response. The introduction of niobium ions leads to the formation of a local stress field, which in turn causes changes in interatomic spacing and angle, resulting in lattice distortion. This distortion not only increases the energy state inside the material, but also significantly slows down the movement speed of grain boundaries by hindering atomic migration paths, thereby limiting grain growth. Uniform and fine grains help reduce internal stress and defects and enhance the mobility of domain walls, which is the main reason for the enhanced Young's modulus. The piezoelectric constant d of the piezoelectric ceramic element obtained in Comparative Example 1. 33 =570pC / N, Young's modulus Compared to Example 12 with the addition of LiNbO3, d 33 The density ρ increased from 570 pC / N to 605 pC / N, and the density ρ increased from 7.7 g / cm³. 3 Increased to 7.8 g / cm³ 3 kp Q increased from 0.61 to 0.64. m The Young's modulus was significantly increased from 154 GPa to 176 GPa, with the value enhanced from 71 to 79. A comparison of Example 12 and Comparative Example 1 shows that the piezoelectric ceramic material obtained in this invention overcomes the contradiction between high piezoelectricity and mechanical strength inherent in traditional PZT ceramics. Through precise control of the Zr / Ti ratio and the innovative combination of LiNbO3 and Li2CO3, the material exhibits significantly superior piezoelectric properties, mechanical strength, and sintering processability compared to traditional formulations, providing a better material solution for the fabrication of high-performance piezoelectric ceramic multilayer actuators for aerospace applications.

[0103] In summary, when x = 0.310, lead nickel niobate-lead zirconate titanate ceramics exhibit the best piezoelectric and mechanical properties: d 33 = 605 pC / N, Curie temperature T m =227℃, relative permittivity ε r =3226, Young's modulus Y 33 =176GPa, maximum strain S max =0.15%, effective piezoelectric coefficient d 33 * = 741 pm / V (@E = 2 kV / mm). The introduction of LiNbO3 not only improves the piezoelectric response by 6%, but also increases the mechanical strength by 15%. By innovatively adjusting the content of zirconium (Zr) and titanium (Ti) and synergistically introducing LiNbO3 and Li2CO3, a significant improvement in material properties is achieved, overcoming the contradiction between high piezoelectricity and mechanical strength in traditional PZT ceramics.

Claims

1. A low-temperature sintered lead nickel niobate-lead zirconate titanate piezoelectric ceramic material possessing both high Curie temperature and high Young's modulus, characterized in that, The chemical composition of the low-temperature sintered lead nickel niobate-lead zirconate titanate piezoelectric ceramic material is: 0.3Pb(Ni 1 / 3Nb 2 / 3 )O3-xPbZrO3-(0.7-x)PbTiO3+1.8 mol% LiNbO3+2 mol% Li2CO3, where 0.300≤x≤0.320; The Curie temperature of the low-temperature sintered lead nickel niobate-lead zirconate titanate piezoelectric ceramic material is 220-229℃. The Young's modulus of the low-temperature sintered lead nickel niobate-lead zirconate titanate piezoelectric ceramic material is 165-176 GPa. The piezoelectric constant of the low-temperature sintered lead nickel niobate-lead zirconate titanate piezoelectric ceramic material is 517-607 pC / N. The preparation of the low-temperature sintered lead nickel niobate-lead zirconate titanate piezoelectric ceramic material includes: using PbO or Pb3O4, ZrO2, TiO2, Ni2O3 or NiO, Nb2O5 and Li2CO3 as raw materials, preparing ceramic powder according to the chemical composition of the lead nickel niobate-lead zirconate titanate piezoelectric ceramic material, forming it and sintering it at 1000-1120℃ to obtain the low-temperature sintered lead nickel niobate-lead zirconate titanate piezoelectric ceramic material.

2. A method for preparing a low-temperature sintered lead niobate-lead zirconate titanate piezoelectric ceramic material with both high Curie temperature and high Young's modulus as described in claim 1, characterized in that, include: (1) Using PbO or Pb3O4, ZrO2, TiO2, Ni2O3 or NiO, Nb2O5 and Li2CO3 as raw materials, weigh the raw materials according to the chemical composition of lead nickel niobate-lead zirconate titanate piezoelectric ceramic materials and mix them. After pre-firing treatment, the ceramic powder is obtained. (2) The obtained ceramic powder is finely ground and pressed into shape to obtain a ceramic blank; (3) The obtained ceramic blank is sintered to obtain the low-temperature sintered lead nickel niobate-lead zirconate titanate piezoelectric ceramic material.

3. The preparation method according to claim 2, characterized in that, In step (1), the mixing method is wet ball milling. The parameters of wet ball milling include: the mass ratio of raw material powder: ball milling medium: solvent is 1:(3.0~5.0):(0.8~1.5), and the ball milling time is 4~24 hours. The pre-firing treatment is performed at a temperature of 700–800°C for 2–4 hours, with a heating rate of 2–5°C / minute.

4. The preparation method according to claim 2, characterized in that, In step (2), the fine grinding method is wet ball milling. The parameters of wet ball milling include: the mass ratio of ceramic powder: ball milling medium: solvent is 1:(3.0~5.0):(0.8~1.5), and the ball milling time is 4~24 hours.

5. The preparation method according to claim 2, characterized in that, In step (2), before pressing and molding, the finely ground ceramic powder is mixed with a binder for granulation, and then aged and sieved; the amount of binder added is 4 to 8 wt.% of the ceramic powder; the aging time is 22 to 26 hours.

6. The preparation method according to claim 2, characterized in that, In step (3), the sintering temperature is 1000-1120℃, the time is 2-4 hours, and the heating rate is 2-5℃ / minute.

7. The preparation method according to claim 2, characterized in that, Before sintering, the ceramic blank is debinded in the air; the debinding temperature is 550-700℃ and the time is 2-4 hours.

8. The preparation method according to any one of claims 2-7, characterized in that, Silver electrodes were prepared on the upper and lower surfaces of the obtained low-temperature sintered lead nickel niobate-lead zirconate titanate piezoelectric ceramic material, and then polarization treatment was performed. The parameters of the polarization treatment include: the polarization field strength is 3-4 kV / mm; the polarization temperature is 80-120℃; and the polarization time is 10-30 minutes.

9. The application of a low-temperature sintered lead niobate-lead zirconate titanate piezoelectric ceramic material with both high Curie temperature and high Young's modulus as described in claim 1 in a piezoelectric ceramic stacked actuator.

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