CN114478006A

CN114478006A - KNNS-BNZ + CuO piezoceramic material and preparation method and application thereof

Info

Publication number: CN114478006A
Application number: CN202111669999.5A
Authority: CN
Inventors: 张斗; 迟文潮; 周学凡; 邹金住
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2022-05-13

Abstract

The invention belongs to the field of functional ceramic materials, and particularly discloses a KNNS-BNZ + CuO piezoceramic material, a preparation method and application thereof, wherein the solid-solution ceramic material has the following chemical formula: (1-x) [0.95 (K)_0.5Na_0.5)(Nb_0.95Sb_0.05)O_3‑0.05Bi_0.5Na_0.5ZrO₃]+ xCuO; wherein x is 0.002-0.02. The invention also provides the preparation and application of the material, and the preparation of KNNS-BNZ powder and the solid solution doping of CuO on KNNS-BNZ are helpful to improve the compactness of the prepared product and reduce the defects. The research of the invention discovers that the brand-new KNN-based piezoelectric ceramic material has good piezoelectric coefficient d₃₃Mechanical quality factor Q_mThe KNNS-BNZ + CuO piezoelectric ceramic material is suitable for piezoelectric device application under high frequency.

Description

KNNS-BNZ + CuO piezoceramic material and preparation method and application thereof

Technical Field

The invention relates to the technical field of lead-free piezoelectric ceramics, in particular to a KNNS-BNZ + CuO piezoelectric ceramic material and a preparation method and application thereof.

Background

Among functional materials, piezoelectric materials can realize interconversion of electrical energy and mechanical energy, and are key components of many electronic components, such as sensors, micro-displacers, drivers, transducers, energy collectors and the like. Piezoelectric performance and mechanical quality factor are critical in practical applications. In lead-free piezoelectric ceramic materials, potassium sodium niobate (K)_0.5Na_0.5NbO₃KNN-based piezoelectric materials having a high piezoelectric coefficient (d)₃₃500pC/N), low coercive field (E)_c10kV/cm) and a high Curie temperature (T)_c410 deg.c), etc. and has excellent piezoelectric application foreground. To increase d₃₃Generally, doping substitution is carried out on A/B ion sites of the KNN-based piezoelectric material, so that a multiphase coexisting structure is realized at room temperature, and finally, the optimized electrical performance is obtained. In recent years, with the continuous improvement of piezoelectric performance and temperature stability of KNN-based piezoelectric ceramics, commercial PZT 3 and PZT 4(d) have been reached or even exceeded in piezoelectric performance₃₃500pC/N) and is expected to be applied to piezoelectric devices such as sensors with higher piezoelectric performance requirements. However, the KNN-based piezoelectric ceramic obtains higher piezoelectric performance and simultaneously has a mechanical quality factor Q_mLow (-30-50) and difficult to meet the application requirements of high power and high frequency devices, such as ultrasonic atomizers and the like. Therefore, it is highly desirable to find a method for raising Q_mWithout unduly damaging d₃₃An effective method of (1).

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a KNNS-BNZ + CuO piezoceramic material and a preparation method and application thereof₃₃Mechanical quality factor Q_mThe novel KNN-based piezoelectric ceramic material solves the problems mentioned in the background art.

In order to achieve the purpose, the invention provides the following technical scheme: a KNNS-BNZ + CuO piezoceramic material, said piezoceramic material having the chemical formula: (1-x) [0.95 (K)_0.5Na_0.5)(Nb_0.95Sb_0.05)O_3-0.05Bi_0.5Na_0.5ZrO₃]+ xCuO; wherein x is 0.002-0.02;

the piezoelectric ceramic material has the ceramic piezoelectric coefficient d by adding CuO content₃₃Is 269 pC/N; its ceramic mechanical quality factor Q_mLifted from 33 to 168.7.

Preferably, the chemical formula of the piezoceramic material is as follows: (1-x) [0.95 (K)_0.5Na_0.5)(Nb_0.95Sb_0.05)O_3-0.05Bi_0.5Na_0.5ZrO₃]+ xCuO; wherein x is 0.008-0.01.

In order to achieve the above purpose, the invention also provides the following technical scheme: a preparation method of KNNS-BNZ + CuO piezoceramic material comprises the following steps:

s1, preparing KNNS-BNZ powder;

s2 and CuO are used for carrying out solid solution doping on KNNS-BNZ.

Preferably, the preparation of KNNS-BNZ in step S1 is specifically: according to 0.95 (K)_0.5Na_0.5)(Nb_0.95Sb_0.05)O_3-0.05Bi_0.5Na_0.5ZrO₃Weighing raw materials containing K, Na, Nb, Sb, Bi and Zr according to the stoichiometric ratio, mixing, ball-milling to obtain a mixed material A, and calcining to obtain KNNS-BNZ powder.

Preferably, the solid solution doping of KNNS-BNZ by CuO in step S2 is specifically: adding CuO into KNNS-BNZ, performing ball milling and mixing to obtain a mixed material B, and then performing sintering and solution treatment.

Preferably, the raw materials containing K, Na, Nb, Sb, Bi, and Zr elements are specifically: at least one of an oxide, a carbonate, a bicarbonate, and a nitrate containing at least one of the elements.

Preferably, the rotation speed of the ball milling is 200-300 rpm, and the ball milling time is 6-12 h; the calcination temperature is 850-950 ℃, preferably 900-950 ℃, and the calcination time is 2-4 h.

The ball milling can be dry ball milling or wet ball milling.

Preferably, the rotation speed of the ball milling is 300-400 rpm, and the ball milling time is 18-24 h; the sintering process comprises a first stage sintering and a second stage sintering; the first-stage sintering comprises the following steps: heating to 550-650 ℃ at the speed of 1-3 ℃/min, and preserving heat for 2-4 h; the second-stage sintering comprises the following steps: heating to 1100-1180 ℃ at the speed of 4-6 ℃/min, and preserving heat for 2-4 h.

In order to achieve the above purpose, the invention also provides the following technical scheme: the application of the KNNS-BNZ + CuO piezoceramic material uses the KNNS-BNZ + CuO piezoceramic material as a piezoelectric material.

Preferably, a KNNS-BNZ + CuO piezoceramic material is used for the silver-coated electrode: and (3) grinding and polishing the piezoelectric material, coating medium-temperature silver paste on two surfaces, and carrying out heat preservation at the temperature of 500-600 ℃ for 25-35min to obtain a silver electrode.

In order to achieve the above purpose, the invention also provides the following technical scheme: a piezoelectric device comprising the KNNS-BNZ + CuO piezoelectric material.

The invention has the beneficial effects that:

1) the invention can successfully prepare the new ceramic material by preparing KNNS-BNZ in advance and then carrying out solid solution sintering with CuO, thereby effectively improving the compactness and reducing the defects, and the material prepared by the preparation method can show good piezoelectric coefficient d₃₃Mechanical quality factor Q_m(ii) a Can mix the ceramics d₃₃The change from 298pC/N to 269pC/N remained high₃₃. Can also obviously improve the mechanical quality factor Q of the ceramic_mSuccessfully mix the ceramic Q_mFrom 33 to 168.7.

2) The invention adopts the simplest and lowest-cost traditional solid phase method, and is formed by one-time presintering and one-time sintering, and the sintering temperature is very critical. The sintering temperature is too low, so that the ceramic is not completely sintered and cannot form a compact ceramic block; the excessive sintering temperature can cause abnormal growth of ceramic grains and excessive sintering of the ceramic. Both under-burning and over-burning cause a great deal of defects in the ceramics, are easy to break down,

3) in the invention, CuO is completely dissolved into KNNS-BNZ in a solid solution mode, and the content of CuO is critical: with the addition of CuO, the mechanical quality factor Q of the ceramic_mPresenting a trend of increasing first and then decreasing; when the CuO content is too low (x is 0.002), the ceramic Q may be caused_mIs greatly improved, but d₃₃The temperature is greatly reduced; when the CuO content is further increased (x ═ 0.004, 0.006, and 0.008), ceramic d results₃₃And Q_mThere is a further boost; when the CuO content is further increased (x ═ 0.01), d₃₃And Q_mThe highest value is reached; when the CuO content is too high (x is 0.02), d may be caused₃₃And Q_mDecrease; general consideration of d₃₃And Q_m. Preferably, x is 0.006 to 0.02, preferably 0.008 to 0.01. It has been found that, at this preferred ratio, a better piezoelectric coefficient d can be obtained₃₃Mechanical quality factor Q_m。

Drawings

FIG. 1 is a graph of the characterization of the properties of 0.99(KNNS-BNZ) +0.01CuO ceramic prepared in example 1; FIG. 1(a) is an X-ray diffraction pattern, and FIG. 1(b) is a piezoelectric coefficient d₃₃FIG. 1(c) is a surface view of a scanning electron microscope, FIG. 1(d) is a cross-sectional view of a scanning electron microscope, FIG. 1(e) is a graph of impedance and phase angle as a function of frequency, and FIG. 1(f) is a graph of dielectric constant and loss as a function of temperature;

FIG. 2 is a graph of the performance characteristics of 0.992(KNNS-BNZ) +0.008CuO ceramic prepared in example 2; FIG. 2(a) is an X-ray diffraction spectrum, and FIG. 2(b) is a piezoelectric coefficient d₃₃FIG. 2(c) is a surface view of a scanning electron microscope, FIG. 2(d) is a cross-sectional view of a scanning electron microscope, FIG. 2(e) is a graph of impedance and phase angle as a function of frequency, and FIG. 2(f) is a graph of dielectric constant and loss as a function of temperature;

FIG. 3 is a graph of the performance characteristics of 0.998(KNNS-BNZ) +0.002CuO ceramic prepared in example 3; FIG. 3(a) is an X-ray diffraction pattern, and FIG. 3(b) is a piezoelectric coefficient d₃₃FIG. 3(c) is a surface view of a scanning electron microscope, FIG. 3(d) is a cross-sectional view of a scanning electron microscope, FIG. 3(e) is a plot of impedance and phase angle as a function of frequency, and FIG. 3(f) is a plot of dielectric constant and loss as a function of temperature;

FIG. 4 is a graph of the performance characteristics of 0.996(KNNS-BNZ) +0.004CuO ceramic prepared in example 4; FIG. 4(a) is an X-ray diffraction pattern, and FIG. 4(b) is a piezoelectric coefficient d₃₃FIG. 4(c) is a surface view of a scanning electron microscope, and FIG. 4(d) is a scanning electron microscopeDrawing an electron microscope cross-sectional view, FIG. 4(e) is a plot of impedance and phase angle as a function of frequency, and FIG. 4(f) is a plot of dielectric constant and loss as a function of temperature;

FIG. 5 is a graph of the performance characteristics of the 0.994(KNNS-BNZ) +0.006CuO ceramic prepared in example 5; FIG. 5(a) is an X-ray diffraction pattern, and FIG. 5(b) is a piezoelectric coefficient d₃₃FIG. 5(c) is a surface view of a scanning electron microscope, FIG. 5(d) is a cross-sectional view of a scanning electron microscope, FIG. 5(e) is a graph of impedance and phase angle as a function of frequency, and FIG. 5(f) is a graph of dielectric constant and loss as a function of temperature;

FIG. 6 is a graph of the performance characteristics of the 0.98(KNNS-BNZ) +0.02CuO ceramic prepared in example 6; FIG. 6(a) is an X-ray diffraction pattern, and FIG. 6(b) is a piezoelectric coefficient d₃₃FIG. 6(c) is a surface view of a scanning electron microscope, FIG. 6(d) is a cross-sectional view of a scanning electron microscope, FIG. 6(e) is a graph of impedance and phase angle as a function of frequency, and FIG. 6(f) is a graph of dielectric constant and loss as a function of temperature;

FIG. 7 is a graph of a performance characterization of the KNNS-BNZ ceramic prepared in comparative example 1; FIG. 7(a) is an X-ray diffraction pattern, and FIG. 7(b) is a piezoelectric coefficient d₃₃FIG. 7(c) is a surface view of a scanning electron microscope, FIG. 7(d) is a cross-sectional view of a scanning electron microscope, FIG. 7(e) is a graph of impedance and phase angle as a function of frequency, and FIG. 7(f) is a graph of dielectric constant and loss as a function of temperature;

FIG. 8 is a graph of the characterization of the properties of the 0.99(KNNS-BNZ) -0.01CuO ceramic prepared in comparative example 2; FIG. 8(a) is an X-ray diffraction pattern, and FIG. 8(b) is a piezoelectric coefficient d₃₃FIG. 8(c) is a surface view of a scanning electron microscope, FIG. 8(d) is a cross-sectional view of a scanning electron microscope, FIG. 8(e) is a graph showing changes in impedance and phase angle with frequency, and FIG. 8(f) is a graph showing changes in dielectric constant and loss with temperature.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Preparation and characterization of 0.99(KNNS-BNZ) +0.01CuO ceramic

According to 0.95 (K)_0.5Na_0.5)(Nb_0.95Sb_0.05)O_3-0.05Bi_0.5Na_0.5ZrO₃Weighing K in a molar stoichiometric ratio of₂CO₃、Na₂CO₃、Nb₂O₅、Sb₂O₅、Bi₂O₃And ZrO₂And uniformly mixing the powder, putting the prepared material into a nylon tank which takes absolute ethyl alcohol as a medium and zirconia balls as grinding balls, performing primary ball milling, and performing ball milling for 8 hours at the rotating speed of 250 r/min. And drying the ball-milled slurry at 80 ℃. And (3) sieving the dried powder with a 200-mesh sieve, placing the powder in an alumina crucible, and pre-burning for 3 hours at 930 ℃ to obtain KNNS-BNZ pre-burnt powder. Mixing KNNS-BNZ pre-sintered powder and CuO powder according to a molar ratio of 0.99: weighing 0.01, putting the mixture into a nylon tank which takes absolute ethyl alcohol as a medium and zirconia balls as grinding balls for secondary ball milling, carrying out ball milling for 24 hours at the rotating speed of 350r/min, and drying at 80 ℃. Sieving the powder, adding 3% polyvinyl butyral, grinding to obtain uniform powder, and pressing under 20-30Mpa for 3-8min to obtain cylindrical green compact with diameter of 8-12mm and thickness of 1-1.4 mm. Placing the green body in an alumina crucible, burning the green body in a burying way by using pre-burning powder with the same components, firstly keeping the temperature for 2h to remove the binder at the temperature of 550 ℃ at the heating rate of 3 ℃/min (first-stage sintering), then keeping the temperature for 3h to sinter at the temperature of 1130 ℃ at the heating rate of 5 ℃/min (second-stage sintering), and naturally cooling along with a furnace to prepare the 0.99(KNNS-BNZ) +0.01CuO ceramic material.

The crystal phase detection is carried out on the 0.99(KNNS-BNZ) +0.01CuO ceramic material by X-ray diffraction analysis (XRD). As shown in fig. 1(a), it can be seen that the ceramic material prepared is a pure perovskite structure, and no impurity phase exists.

And polishing the sintered ceramic wafer to the thickness of 0.6mm, coating high-temperature platinum slurry on two surfaces, and keeping the temperature at 850 ℃ for 10min to sinter the ceramic wafer into a platinum electrode.The platinum-coated ceramic sheet is polarized and used for the piezoelectric coefficient d₃₃. And (3) polarization process: the ceramic was placed in silicone oil at 60 ℃ and polarized for 30min at a direct voltage of 3.5 kV/mm. Placing for 24h and then adopting a quasi-static state d₃₃Tester test d₃₃And (4) the coefficient. As can be seen from FIG. 1(b), 0.99(KNNS-BNZ) +0.01CuO ceramic d at room temperature₃₃Is 269.1 pC/N.

The resulting 0.99(KNNS-BNZ) +0.01CuO ceramic material was examined by Scanning Electron Microscopy (SEM). As can be seen from fig. 1(c) and 1(d), the prepared ceramic has no obvious defects, and has good compactness and good crystallinity.

And (5) placing the polarized ceramic wafer for 24h, and then carrying out dielectric spectrum test and dielectric temperature spectrum test. As can be seen from FIGS. 1(e) and 1(f), the mechanical quality factor of 0.99(KNNS-BNZ) +0.01CuO ceramic is k_t0.51 mechanical quality factor Q_m168.72, dielectric loss tan delta 0.0198, Curie temperature T_cUp to 205 ℃.

Example 2

Preparation and characterization of 0.992(KNNS-BNZ) +0.008CuO ceramic the preparation conditions were the same as in example 1 except that the molar ratio of KNNS-BNZ pre-fired powder to CuO powder was 0.992: 0.008 weight.

The structural characterization and performance testing procedures were the same as in example 1. XRD and SEM results show that the ceramic material of 0.992(KNNS-BNZ) +0.008CuO is of a pure perovskite structure, and no impurity phase exists. Piezoelectric coefficient d of 0.992(KNNS-BNZ) +0.008CuO ceramic₃₃186.8 and a mechanical quality factor k_t0.44, mechanical quality factor Q_m156.95, dielectric loss tan delta 0.0535, Curie temperature T_cUp to 227 ℃. The characterization and test results are shown in fig. 2(a) -2 (f).

Example 3

Preparation and characterization of 0.998(KNNS-BNZ) +0.002CuO ceramic the preparation conditions were the same as in example 1 except that the molar ratio of KNNS-BNZ pre-sintered powder to CuO powder was set to 0.998: 0.002 weight.

The structural characterization and performance testing procedures were the same as in example 1. XRD and SEM results show that the ceramic material of 0.998(KNNS-BNZ) +0.002CuO is of a pure perovskite structureNo impurity phases are present. Piezoelectric coefficient d of 0.998(KNNS-BNZ) +0.002CuO ceramic₃₃Is 114.7 and the mechanical quality factor is k_t0.23, mechanical quality factor Q_m108.7, dielectric loss tan delta 0.1894, Curie temperature T_cUp to 226 ℃. The characterization and test results are shown in fig. 3(a) -3 (f).

Example 4

Preparation and characterization of 0.996(KNNS-BNZ) +0.004CuO ceramic the preparation conditions were the same as in example 1 except that the molar ratio of KNNS-BNZ pre-sintered powder to CuO powder was set to 0.996: 0.004 and weigh.

The structural characterization and performance testing procedures were the same as in example 1. XRD and SEM results show that the ceramic material of 0.996(KNNS-BNZ) +0.004CuO is of a pure perovskite structure, and no impurity phase exists. Piezoelectric coefficient d of 0.996(KNNS-BNZ) +0.004CuO ceramic₃₃170.1, mechanical quality factor k_t0.40, mechanical quality factor Q_m115.63, dielectric loss tan delta 0.0613, Curie temperature T_cUp to 228 ℃. The characterization and test results are shown in fig. 4(a) -4 (f).

Example 5

Preparation and characterization of 0.994(KNNS-BNZ) +0.006CuO ceramic the preparation conditions were the same as in example 1 except that the molar ratio of KNNS-BNZ pre-fired powder to CuO powder was set to 0.994: 0.006 weight percent.

The structural characterization and performance testing procedures were the same as in example 1. XRD and SEM results show that the ceramic material of 0.994(KNNS-BNZ) +0.006CuO is of a pure perovskite structure, and no impurity phase exists. Piezoelectric coefficient d of 0.994(KNNS-BNZ) +0.006CuO ceramic₃₃178.9, mechanical quality factor k_t0.44, mechanical quality factor Q_m157, dielectric loss tan delta 0.0535, Curie temperature T_cUp to 227 ℃. The characterization and test results are shown in fig. 5(a) -5 (f).

Example 6

Preparation and characterization of 0.98(KNNS-BNZ) +0.02CuO ceramic the preparation conditions were the same as in example 1 except that the molar ratio of KNNS-BNZ pre-sintered powder to CuO powder was 0.98: 0.02 weight.

Structure characterization and Performance test procedure in example 1The same is true. XRD and SEM results show that 0.98(KNNS-BNZ) O₃+0.02CuO ceramic material is pure perovskite structure and has no impurity phase. 0.98(KNNS-BNZ) O₃+0.02CuO ceramic piezoelectric coefficient d₃₃183.6, mechanical quality factor k_t0.39 mechanical quality factor Q_m80.5, dielectric loss tan delta 0.1306, Curie temperature T_cUp to 226 ℃. The characterization and test results are shown in fig. 6(a) -6 (f).

Comparative example 1

Preparation and characterization of KNNS-BNZ ceramics

The preparation conditions were the same as in example 1, except that the powder obtained by the second ball milling was KNNS-BNZ pre-sintered powder only.

The structural characterization and performance testing procedures were the same as in example 1. XRD and SEM results show that the KNNS-BNZ ceramic material has a pure perovskite structure and no impurity phase exists. Piezoelectric coefficient d of KNNS-BNZ ceramic₃₃298.2, mechanical quality factor k_t0.48, mechanical quality factor Q_m33, dielectric loss tan delta 0.0574, Curie temperature T_cUp to 226 ℃. The characterization and test results are shown in fig. 7(a) -7 (f). As can be seen, the KNNS-BNZ ceramic not doped with CuO has a high piezoelectric coefficient d₃₃And a mechanical quality factor k_tBut with a mechanical quality factor Q comparable to that of 0.99(KNNS-BNZ) -0.01CuO ceramic_mVery low, only 33.

Comparative example 2

Directly carrying out powder proportioning and pre-burning according to a chemical formula of 0.99(KNNS-BNZ) -0.01CuO, and then carrying out ceramic preparation.

According to 0.99[0.95 (K)_0.5Na_0.5)(Nb_0.95Sb_0.05)O_3-0.05Bi_0.5Na_0.5ZrO₃]Molar stoichiometric ratio of-0.01 CuO K is weighed out₂CO₃、Na₂CO₃、Nb₂O₅、Sb₂O₅、Bi₂O₃、ZrO₂And CuO powder are uniformly mixed, and ball milling, drying and presintering are carried out under the same conditions as in example 1. 0.99(KNNS-BNZ) -0.01CuO pre-sintered powder was ball-milled, dried, pressed and sintered under the same conditions as in example 1,0.99(KNNS-BNZ) -0.01CuO ceramic is prepared.

The structural characterization and performance test procedures were the same as in example 1. XRD and SEM results show that the ceramic material of 0.99(KNNS-BNZ) -0.01CuO is of a pure perovskite structure and no impurity phase exists. Piezoelectric coefficient d of 0.99(KNNS-BNZ) -0.01CuO ceramic₃₃Is 154.7 and the mechanical quality factor is k_t0.34, mechanical quality factor Q_m66.7, dielectric loss tan delta 0.1753, Curie temperature T_cUp to 226 ℃. As shown in fig. 8(a) -8 (f) of fig. 8, it can be seen that, by doping CuO in the same amount in a mixing manner, the obtained ceramic has much lower performance than the doped CuO after pre-firing.

The invention provides a brand-new KNN-based piezoelectric ceramic material which has a good piezoelectric coefficient d₃₃Mechanical quality factor Q_mResearch shows that the new KNN-based piezoelectric ceramic material can increase the CuO content to form ceramic d₃₃The change from 298pC/N to 269pC/N remained high₃₃. Can also obviously improve the mechanical quality factor Q of the ceramic_mSuccessfully mix the ceramic Q_mFrom 33 to 168.7, the piezoelectric material is suitable for piezoelectric device application at high frequency.

The invention can successfully prepare the new ceramic material by preparing KNNS-BNZ in advance and then carrying out solid solution sintering with CuO, thereby effectively improving the compactness and reducing the defects, and the material prepared by the preparation method can show good piezoelectric coefficient d₃₃Mechanical quality factor Q_m。

The inventors found that CuO was completely solid-dissolved into KNNS-BNZ. The content of CuO is crucial: with the addition of CuO, the piezoelectric coefficient and the mechanical quality factor of the ceramic show a trend of increasing first and then decreasing; when the CuO content is too low (x is 0.002), the ceramic Q may be caused_mIs greatly improved, but d₃₃The temperature is greatly reduced; when the CuO content is further increased (x ═ 0.004, 0.006, and 0.008), ceramic d results₃₃And Q_mThere is a further boost; when the CuO content is further increased (x ═ 0.01), d₃₃And Q_mReaching a maximum value; when the CuO content is too high (x is 0.02), d may be caused₃₃And Q_mDecrease; the piezoelectric coefficient and the mechanical quality factor are comprehensively considered. Preferably, x is 0.006 to 0.02, preferably 0.008 to 0.01. It has been found that, at this preferred ratio, a better piezoelectric coefficient d can be obtained₃₃Mechanical quality factor Q_m。

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and/or modifications of the invention can be made, and equivalents and modifications of some features of the invention can be made without departing from the spirit and scope of the invention.

Claims

1. A KNNS-BNZ + CuO piezoceramic material, characterized in that said piezoceramic material has the chemical formula: (1-x) [0.95 (K)_0.5Na_0.5)(Nb_0.95Sb_0.05)O_3-0.05Bi_0.5Na_0.5ZrO₃]+ xCuO; wherein x is 0.002-0.02;

2. The KNNS-BNZ + CuO piezoceramic material of claim 1, wherein: the chemical formula of the piezoceramic material is as follows: (1-x) [0.95 (K)_0.5Na_0.5)(Nb_0.95Sb_0.05)O_3-0.05Bi_0.5Na_0.5ZrO₃]+ xCuO; wherein x is 0.008-0.01.

3. A method of making a KNNS-BNZ + CuO piezoceramic material according to any of claims 1-2, characterized in that: the method comprises the following steps:

s1, preparing KNNS-BNZ powder;

s2 and CuO are used for carrying out solid solution doping on KNNS-BNZ.

4. The method of making a KNNS-BNZ + CuO piezoceramic material of claim 3, wherein: the preparation of KNNS-BNZ in step S1 is specifically: according to 0.95 (K)_0.5Na_0.5)(Nb_0.95Sb_0.05)O_3-0.05Bi_0.5Na_0.5ZrO₃Weighing raw materials containing K, Na, Nb, Sb, Bi and Zr according to the stoichiometric ratio, mixing, ball-milling to obtain a mixed material A, and calcining to obtain KNNS-BNZ powder.

5. The method of making a KNNS-BNZ + CuO piezoceramic material of claim 3, wherein: the solid solution doping of KNNS-BNZ by CuO in the step S2 specifically comprises the following steps: adding CuO into KNNS-BNZ, performing ball milling and mixing to obtain a mixed material B, and then performing sintering and solution treatment.

6. The method of making a KNNS-BNZ + CuO piezoceramic material of claim 4, wherein: the raw materials containing K, Na, Nb, Sb, Bi and Zr are as follows: at least one of an oxide, a carbonate, a bicarbonate, and a nitrate containing at least one of the elements.

7. The method of making a KNNS-BNZ + CuO piezoceramic material of claim 4, wherein: the rotation speed of the ball milling is 200-300 rpm, and the ball milling time is 6-12 h; the calcining temperature is 850-950 ℃, and the calcining time is 2-4 h.

8. The method of making a KNNS-BNZ + CuO piezoceramic material of claim 5, wherein: the rotation speed of the ball milling is 300-400 rpm, and the ball milling time is 18-24 h; the sintering process comprises a first stage sintering and a second stage sintering; the first-stage sintering comprises the following steps: heating to 550-650 ℃ at the speed of 1-3 ℃/min, and preserving heat for 2-4 h; the second-stage sintering comprises the following steps: heating to 1100-1180 ℃ at the speed of 4-6 ℃/min, and preserving heat for 2-4 h.

9. Use of a KNNS-BNZ + CuO piezoceramic material according to any of claims 1 to 2 or prepared by the preparation method according to any of claims 3 to 8, characterized in that: KNNS-BNZ + CuO piezoceramic material is used as the piezoelectric material.

10. The KNNS-BNZ + CuO piezoceramic material according to claim 9, wherein: KNNS-BNZ + CuO piezoceramic material is used for the silver electrode.