CN106565235B - Composite high-temperature piezoelectric ceramic material and preparation method thereof - Google Patents

Abstract

The invention discloses a composite high-temperature piezoelectric ceramic material which comprises two-phase ceramic, wherein one phase is CaBi₄Ti₄O₁₅Ceramic, another phase is BiFeO₃Ceramics of the general formula CaBi₄Ti₄O₁₅‑xBiFeO₃Wherein x is 0.2 to 0.4. The invention also discloses a preparation method of the composite high-temperature piezoelectric ceramic material. The piezoelectric constant and the resistivity of the composite piezoelectric ceramic material are both larger than those of single-phase CaBi₄Ti₄O₁₅The piezoelectric ceramic material is made to have a better ratio than single-phase CaBi₄Ti₄O₁₅The piezoelectric ceramic material is more suitable for preparing piezoelectric sensor devices and piezoelectric drivers working under high temperature conditions. The preparation method has the advantages of stable process, simple operation, no need of special equipment and harsh conditions, and easy large-scale production.

Description

Composite high-temperature piezoelectric ceramic material and preparation method thereof

Technical Field

The invention belongs to the field of inorganic piezoelectric materials, and particularly relates to a composite high-temperature piezoelectric ceramic material and a preparation method thereof.

Background

The piezoelectric material widely used at present is mainly PZT (PbZr 0) with a perovskite structure₃-PbTi0₃) And PT (PbTi 0)₃) A material. However, the Curie temperatures of PZT and PT systems are around 300-350 degrees and 460-490 degrees, respectively. And the piezoelectric property is unstable due to depolarization caused by temperature rise, so that the upper limit of the working temperature is 1/2 of Curie temperature Tc, and the service temperature of PZT and PT piezoelectric ceramics is below 200 ℃ and is only suitable for being used under the conventional condition. With the development of industries such as automobiles, aerospace, steel making and the like, the piezoelectric device is required to be used at a temperature of 350-400 ℃, even above 400 ℃. And PZT and PT ceramic materials contain a large amount of Pb, and can cause damage and pollution to human bodies and surrounding environment to different degrees in the processes of production, manufacture, use and waste, so people urgently hope to replace the lead-free piezoceramic materials by proper lead-free piezoceramic materials. Therefore, there is a need to develop a lead-free piezoelectric ceramic material that can be used at high temperatures.

The bismuth layer structure lead-free piezoelectric ceramic has higher performanceCurie temperature and good fatigue resistance, so the material is suitable for high-temperature and high-frequency occasions. Wherein, CaBi₄Ti₄O₁₅The Curie temperature Tc is as high as 790 ℃, and is a material with higher Curie point in the bismuth layer-shaped material. Meanwhile, the material has lower relative dielectric constant and dielectric loss tan delta, and has potential application value in the manufacturing aspect of devices such as high-temperature piezoelectric sensors, transducers and the like. CaBi₄Ti₄O₁₅The high-temperature-resistant material has the advantages of large mechanical quality factor Qm, low electromechanical coupling coefficient Kt, good temperature stability of resonance frequency (TCF is approximately equal to-30 ppm/DEG C), and great advantages in resonators and filters, especially in frequency control devices in high-temperature environments. However, the existing bismuth layer structure materials still have various defects, such as lower piezoelectric coefficient d₃₃And the bismuth ions are seriously volatilized at high temperature, and the comprehensive performance can not completely meet the requirements. BiFeO₃Material ratio of CaBi₄Ti₄O₁₅The material has higher piezoelectric coefficient d₃₃And Curie temperature, but its resistivity at high temperature is low, limiting BiFeO₃Use of the material at high temperatures.

Mixing two systems with complementary properties is one of the effective means for improving bismuth layer-structured ceramic materials. In 1978, professor r.e. newham, university of pennsylvania, materials laboratories, usa, was pioneered in the concept of "connectivity" of components within a composite material. The phases contained in the composite material may be self-interconnected in a 0, 1, 2 or 3-dimensional manner. If the composite material is composed of two components, there may be 10 modes of communication, i.e., 0-0, 0-1, 0-2, 0-3, 1-1, 1-2, 1-3, 2-2, 2-3, 3-3, the first number representing the dimension of communication between the piezoelectric ceramic and the second number representing the dimension of communication between the matrix and the non-piezoelectric ceramic. The piezoelectric composite material integrates the advantages of materials of various phases and complements the disadvantages of single-phase materials. The 0-3 type piezoelectric composite material is a composite material in which piezoelectric ceramic powder is dispersed in a three-dimensional continuous matrix. The novel ceramic material prepared by the method can obtain a bismuth layer material with excellent performance which cannot be achieved by a monomer system. Therefore, the preparation of a ceramic composition with good comprehensive performances such as piezoelectricity, dielectric property, resistance and the like becomes a research direction with social, economic and ecological values.

Therefore, a new ultra-giant magnetoresistance material is required to solve the above problems.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a composite high-temperature piezoelectric ceramic material.

In order to achieve the above object, the present invention adopts the following technical solutions:

the composite high-temperature piezoelectric ceramic material comprises two-phase ceramic, wherein one phase is CaBi₄Ti₄O₁₅Ceramic, another phase is BiFeO₃Ceramics of the general formula CaBi₄Ti₄O₁₅-xBiFeO₃Wherein x is 0.2 to 0.4.

Further, the CaBi₄Ti₄O₁₅The ceramic is three-dimensional continuous layered ceramic, and the BiFeO₃Ceramic is dispersed in the CaBi₄Ti₄O₁₅And at the grain boundary of the ceramic, the composite high-temperature piezoelectric ceramic material is a 0-3 type composite material.

Has the advantages that: the piezoelectric constant and the resistivity of the composite piezoelectric ceramic material are both larger than those of single-phase CaBi₄Ti₄O₁₅The piezoelectric ceramic material makes the composite piezoelectric ceramic material more than single-phase CaBi₄Ti₄O₁₅The piezoelectric ceramic material is more suitable for preparing piezoelectric sensor devices and piezoelectric drivers working under high temperature conditions.

The invention also discloses a preparation method of the composite high-temperature piezoelectric ceramic material, which comprises the following steps:

a) BiFeO was weighed based on the composite high-temperature piezoceramic material described above₃Powder and CaBi₄Ti₄O₁₅Uniformly mixing the powder to obtain a mixture;

b) drying and grinding the mixture obtained in the step a) to obtain CaBi₄Ti₄O₁₅-xBiFeO₃Powder, wherein x is 0.2-0.4;

c) CaBi obtained in step b)₄Ti₄O₁₅-xBiFeO₃Polyvinyl alcohol accounting for 0.5wt% of the total weight of the powder is added into the powder to be used as a binder, and the mixture is ground again and pressed into a ceramic wafer;

d) keeping the temperature of the ceramic wafer pressed in the step c) at 550 ℃ for 2 hours to remove the glue, then raising the temperature, and sintering at 650-950 ℃, wherein the heat preservation time is 1 hour;

e) brushing silver paste on the upper surface and the lower surface of the ceramic wafer fired in the step d), and preserving heat at 650 ℃ for 15 minutes to remove organic matters in the silver paste, so that the electrode has conductivity, and obtaining a ceramic wafer with a silver electrode;

f) and placing the sintered ceramic sample with the silver electrode in methyl silicone oil, and polarizing by using a high-voltage electric field, wherein the polarizing electric field is 120kV/cm, and the polarizing time is 20-30 minutes, so as to obtain the composite high-temperature piezoelectric ceramic material.

Further, said CaBi in step a)₄Ti₄O₁₅The preparation method of the powder comprises the following steps:

1) CaCO is prepared₃、Bi₂O₃And TiO₂Blending according to the molar ratio of 1:2:4 to be uniformly mixed;

2) sequentially drying, grinding and presintering the mixture obtained in the step 1) to obtain CaBi₄Ti₄O₁₅And (3) powder.

Furthermore, the pre-sintering temperature in the step 2) is 800 ℃, and the pre-sintering time is 2 hours. The CaBi obtained₄Ti₄O₁₅The powder has better effect.

Further, said BiFeO in step a)₃The preparation method of the powder comprises the following steps:

3) bi is added₂O₃And Fe₂O₃According to the mol ratio of 1:1, burdening and uniformly mixing;

4) drying, grinding and presintering the mixture obtained in the step 3) to obtain BiFeO₃And (3) powder. The pre-sintering temperature is 850 ℃, and the pre-sintering time is 2 hours.

Further, the pre-sintering temperature in the step 4) is 850 ℃, and the pre-sintering time is 2 hours. The BiFeO obtained₃The powder has better effect.

Further, the diameter of the ceramic disc in the step c) is 13mm, and the thickness of the ceramic disc is 1 mm.

Has the advantages that: the preparation method of the composite piezoelectric ceramic material has the advantages of stable process, simple operation, no need of special equipment and harsh conditions, and easy large-scale production.

Drawings

FIG. 1 is a schematic structural view of a 0-3 composite material;

FIG. 2 is an X-ray diffraction spectrum of the ceramic samples of examples one, two, three, four and five;

FIG. 3 is the piezoelectric constants of the second, third, fourth and fifth ceramic samples of the examples at different temperatures;

FIG. 4 is the resistivity of the second, third, fourth, and fifth ceramic samples of examples at different temperatures;

FIG. 5 is Kp and Kt at room temperature for the second, third, fourth, and fifth ceramic samples of examples;

FIG. 6 is Q at room temperature for the second, third, fourth, and fifth ceramic samples of examples_m-KpAnd tan δ;

FIG. 7 shows the hysteresis loop of the ceramic samples of examples two, three, four and five at room temperature.

Detailed Description

The present invention will be described in detail with reference to the following embodiments and accompanying drawings.

The first embodiment is as follows:

this example is to analyze pure Bi₂O₃、Fe₂O₃Preparation of BiFeO powder₃(Pure BFO for short) ceramics.

The preparation steps are as follows: 1. will analytically pure Bi₂O₃、Fe₂O₃Weighing the powder according to a molar ratio of 1:1, mixing, putting into a ball milling tank, adding analytically pure absolute ethyl alcohol (accounting for about two-thirds to three-fourths of the volume of the ball milling tank) into the ball milling tank, and putting into a ball mill for ball milling for 8 hours at a rotating speed of 300 r/minWhen the user wants to use the device.

2. And after the ball milling is finished, pouring anhydrous ethanol containing powder into a glass vessel, putting the glass vessel into a 140-DEG oven for drying, grinding the powder by using a mortar after the powder is dried, then pouring the powder into a corundum boat, putting the corundum boat into a muffle furnace for presintering, wherein the presintering temperature is 850 ℃, and the presintering time is 2 hours.

3. And (3) adding polyvinyl alcohol accounting for 0.5wt% of the total weight of the powder into the powder in the step (2) as a binder, grinding again, and pressing into ceramic wafers with the diameter of 13mm and the thickness of about 1 mm.

4. And (4) keeping the temperature of the ceramic wafer pressed in the step (3) at 550 ℃ for 2 hours for glue removal, raising the temperature, and keeping the temperature at 880 ℃ for 1 hour for sintering.

5. And (4) brushing silver paste on the upper surface and the lower surface of the ceramic chip fired in the step (4), and preserving heat at 650 ℃ for 15 minutes to remove organic matters in the silver paste, so that the electrode has conductivity.

6. And putting the sintered ceramic sample with the silver electrode in methyl silicone oil, and polarizing by a high-voltage electric field, wherein the polarizing electric field is 120kV/cm, and the polarizing time is 20-30 minutes.

The sintered Pure BFO ceramic sample was analyzed by X-ray diffractometer and the results are shown in FIG. 2, indicating that the ceramic crystallized well.

Example two:

this example is to analyze pure CaCO₃、Bi₂O₃、TiO₂Preparation of CaBi powder₄Ti₄O₁₅(Pure CBT for short) ceramics.

The preparation steps are as follows: 1. will analyze the pure CaCO₃、Bi₂O₃、TiO₂The powders were weighed in a molar ratio of 1:2:4, mixed and placed in a ball mill pot, analytically pure anhydrous ethanol (approximately two-thirds to three-fourths of the volume of the ball mill pot) was added into the ball mill pot, and the mixture was placed in a ball mill for 8 hours at a rotation speed of 300 rpm.

2. And after the ball milling is finished, pouring anhydrous ethanol containing powder into a glass vessel, putting the glass vessel into a 140-degree oven for drying, grinding the powder by using a mortar after the powder is dried, then pouring the powder into a corundum boat, putting the corundum boat into a muffle furnace for presintering, wherein the presintering temperature is 800 ℃, and the presintering time is 2 hours.

3. And (3) adding polyvinyl alcohol accounting for 0.5wt% of the total weight of the powder into the powder in the step (2) as a binder, grinding again, and pressing into ceramic wafers with the diameter of 13mm and the thickness of about 1 mm.

4. And (4) keeping the temperature of the ceramic wafer pressed in the step (3) at 550 ℃ for 2 hours to remove the glue, raising the temperature, and keeping the temperature at 950 ℃ for 1 hour to sinter.

5. And (4) brushing silver paste on the upper surface and the lower surface of the ceramic chip fired in the step (4), and preserving heat at 650 ℃ for 15 minutes to remove organic matters in the silver paste, so that the electrode has conductivity.

6. And putting the sintered ceramic sample with the silver electrode in methyl silicone oil, and polarizing by a high-voltage electric field, wherein the polarizing electric field is 120kV/cm, and the polarizing time is 20-30 minutes.

The sintered Pure CBT ceramic sample was analyzed by X-ray diffractometer, and the results are shown in FIG. 2, which indicates that the ceramic crystallized well.

Quasi-static d of type JZ-3AN from the institute of Acoustic, Chinese academy of sciences₃₃The tester tests the polarized ceramic sample. As a result, as shown in FIG. 3, d at room temperature of a ceramic sample having a thickness of 0.6mm was measured₃₃=14 pC/N, the piezoelectric constant at room temperature was maintained at 300 degrees and the piezoelectric constant d at 500 degrees₃₃=12 pC/N。

The ceramic samples were tested with an impedance analyzer. As a result, as shown in FIG. 4, the resistivity of the ceramic sample at room temperature was measured to be 10⁸Ω · m, resistivity at 300 degrees of 10⁵Ω · m, resistivity at 500 degrees 10³ Ω·m。

The ceramic samples were tested with an Agilent 4294A impedance analyzer. As a result, as shown in FIGS. 5 and 6, Kp and Kt of the ceramic sample at room temperature were 0.3 and 0.54, respectively, and Q was measured_m-Kp7.36, tan. delta. is 5.1%.

The ceramic samples were tested with a ferroelectric tester. The results are shown in FIG. 7, and the residual polarization intensity of the ceramic sample at room temperature was measured to be 10.2. mu.C/cm²。

Example three:

this example uses BiFeO of the first and second examples₃、CaBi₄Ti₄O₁₅Preparation of CaBi powder₄Ti₄O₁₅-0.2BiFeO₃(CBT-0.2 BFO for short) ceramics.

The preparation steps are as follows: 1. BiFeO obtained in the step 2 in the first embodiment and the step 2 in the second embodiment₃Powder and CaBi₄Ti₄O₁₅The powder is weighed according to the molar ratio of 1:5, mixed and put into a ball milling tank, added with analytically pure absolute ethyl alcohol (accounting for about two-thirds to three-fourths of the volume of the ball milling tank) and put into a ball mill to be milled for 8 hours at the rotating speed of 300 r/min.

2. After the ball milling is finished, pouring the anhydrous ethanol containing the powder into a glass vessel, putting the glass vessel into a 140-DEG oven for drying, adding polyvinyl alcohol accounting for 0.5wt% of the total weight of the powder into the powder after the powder is dried to serve as a binder, grinding the powder again, and pressing the powder into ceramic wafers with the diameter of 13mm and the thickness of about 1 mm.

3. And (3) keeping the temperature of the ceramic wafer pressed in the step (2) at 550 ℃ for 2 hours, removing the glue, raising the temperature, and keeping the temperature at 950 ℃ for 1 hour for sintering.

4. And (3) brushing silver paste on the upper surface and the lower surface of the ceramic chip fired in the step (3), and preserving heat at 650 ℃ for 15 minutes to remove organic matters in the silver paste, so that the electrode has conductivity.

5. And putting the sintered ceramic sample with the silver electrode in methyl silicone oil, and polarizing by a high-voltage electric field, wherein the polarizing electric field is 120kV/cm, and the polarizing time is 20-30 minutes.

The sintered CBT-0.2BFO ceramic sample was analyzed by X-ray diffractometer and the results are shown in FIG. 2, indicating that the ceramic crystallized well.

Quasi-static d of type JZ-3AN from the institute of Acoustic, Chinese academy of sciences₃₃The tester tests the polarized ceramic sample. As a result, as shown in FIG. 3, d at room temperature of a ceramic sample having a thickness of 0.6mm was measured₃₃=18 pC/N, the piezoelectric constant at room temperature was maintained at 300 degrees and the piezoelectric constant d at 500 degrees₃₃=16 pC/N。

The ceramic samples were tested with an impedance analyzer. As a result, as shown in FIG. 4, the resistivity of the ceramic sample at room temperature was measured to be 10⁹Ω · m, resistivity at 300 degrees of 7 × 10⁵Ω · m, resistivity at 500 degrees of 7 × 10³ Ω·m。

The ceramic samples were tested with an Agilent 4294A impedance analyzer. As a result, as shown in FIGS. 5 and 6, Kp and Kt of the ceramic sample at room temperature were 0.32 and 0.57, respectively, and Q was measured_m-KpIt was 12.9 and tan. delta. was 4.2%.

The ceramic samples were tested with a ferroelectric tester. The results are shown in FIG. 7, and the residual polarization intensity of the ceramic sample at room temperature was measured to be 10.7. mu.C/cm²。

The data in combination with FIG. 3, FIG. 4, FIG. 5, FIG. 6, and FIG. 7 show that the piezoelectric constant and resistivity of CBT-0.2BFO ceramic are greater than those of Pure CBT ceramic at different temperatures. Residual polarization at room temperature, Kp, Kt, Q_m-KpGreater than Pure CBT ceramic and tan delta less than Pure CBT ceramic.

Example four:

this example is to analyze pure CaCO₃、Bi₂O₃、TiO₂、Fe₂O₃Preparation of CaBi powder₄Ti₄O₁₅-0.3BiFeO₃(CBT-0.3 BFO for short) ceramics.

The preparation steps are as follows: 1. BiFeO obtained in the step 2 in the first embodiment and the step 2 in the second embodiment₃Powder and CaBi₄Ti₄O₁₅The powder is weighed according to the molar ratio of 3:10, mixed and put into a ball milling tank, added with analytically pure absolute ethyl alcohol (accounting for about two-thirds to three-fourths of the volume of the ball milling tank) and put into a ball mill to be milled for 8 hours at the rotating speed of 300 r/min.

2. After the ball milling is finished, pouring the anhydrous ethanol containing the powder into a glass vessel, putting the glass vessel into a 140-DEG oven for drying, adding polyvinyl alcohol accounting for 0.5wt% of the total weight of the powder into the powder after the powder is dried to serve as a binder, grinding the powder again, and pressing the powder into ceramic wafers with the diameter of 13mm and the thickness of about 1 mm.

3. And (3) keeping the temperature of the ceramic wafer pressed in the step (2) at 550 ℃ for 2 hours, removing the glue, raising the temperature, and keeping the temperature at 950 ℃ for 1 hour for sintering.

4. And (4) brushing silver paste on the upper surface and the lower surface of the ceramic chip fired in the step (3), and preserving heat for 15 minutes at 650 ℃ to remove organic matters in the silver paste, so that the electrode has conductivity.

5. And putting the sintered ceramic sample with the silver electrode in methyl silicone oil, and polarizing by a high-voltage electric field, wherein the polarizing electric field is 120kV/cm, and the polarizing time is 20-30 minutes.

The sintered CBT-0.3BFO ceramic sample was analyzed by X-ray diffractometer and the results are shown in FIG. 2, indicating that the ceramic crystallized well.

Quasi-static d of type JZ-3AN from the institute of Acoustic, Chinese academy of sciences₃₃The tester tests the polarized ceramic sample. As a result, as shown in FIG. 3, d at room temperature of a ceramic sample having a thickness of 0.6mm was measured₃₃=25 pC/N, the piezoelectric constant at room temperature was maintained at 300 degrees and the piezoelectric constant d at 500 degrees₃₃=23 pC/N。

The ceramic samples were tested with an impedance analyzer. As a result, as shown in FIG. 4, the resistivity of the ceramic sample at room temperature was measured to be 10¹¹Ω · m, resistivity at 300 degrees of 2 × 10⁷Ω · m, resistivity at 500 degrees of 6 × 10⁴ Ω·m。

The ceramic samples were tested with an Agilent 4294A impedance analyzer. As a result, as shown in FIGS. 5 and 6, Kp and Kt of the ceramic sample at room temperature were 0.34 and 0.60, respectively, and Q was measured_m-Kp19.6, and tan delta 3.1%.

The ferroelectric tester tests the ceramic samples. As a result, as shown in FIG. 7, the residual polarization intensity of the ceramic sample at room temperature was measured to be 12. mu.C/cm²。

The data combined with FIG. 3, FIG. 4, FIG. 5, FIG. 6, and FIG. 7 show that the piezoelectric constant and resistivity of CBT-0.3BFO ceramic are all greater than those of Pure CBT ceramic at different temperatures. Residual polarization at room temperature, Kp, Kt, Q_m-KpGreater than Pure CBT ceramic and tan delta less than Pure CBT ceramic.

Example five:

this example is to analyze pure CaCO₃、Bi₂O₃、TiO₂、Fe₂O₃Preparation of CaBi powder₄Ti₄O₁₅-0.4BiFeO₃(CBT-0.4 BFO for short) ceramics.

The preparation steps are as follows: 1. BiFeO obtained in the step 2 in the first embodiment and the step 2 in the second embodiment₃Powder and CaBi₄Ti₄O₁₅The powder is weighed according to the molar ratio of 2:5, mixed and put into a ball milling tank, added with analytically pure absolute ethyl alcohol (accounting for about two-thirds to three-fourths of the volume of the ball milling tank) and put into a ball mill to be milled for 8 hours at the rotating speed of 300 r/min.

2. After the ball milling is finished, pouring the anhydrous ethanol containing the powder into a glass vessel, putting the glass vessel into a 140-DEG oven for drying, adding polyvinyl alcohol accounting for 0.5wt% of the total weight of the powder into the powder after the powder is dried to serve as a binder, grinding the powder again, and pressing the powder into ceramic wafers with the diameter of 13mm and the thickness of about 1 mm.

3. And (3) keeping the temperature of the ceramic wafer pressed in the step (2) at 550 ℃ for 2 hours, removing the glue, raising the temperature, and keeping the temperature at 950 ℃ for 1 hour for sintering.

4. And (3) brushing silver paste on the upper surface and the lower surface of the ceramic chip fired in the step (3), and preserving heat at 650 ℃ for 15 minutes to remove organic matters in the silver paste, so that the electrode has conductivity.

5. And (3) placing the sintered ceramic sample with the silver electrode in methyl silicone oil, and polarizing by using a high-voltage electric field, wherein the polarizing electric field is 120kV/cm, and the polarizing time is 20-30 minutes.

The sintered CBT-0.4BFO ceramic sample was analyzed by X-ray diffractometer and the results are shown in FIG. 2, indicating that the ceramic crystallized well.

Quasi-static d of type JZ-3AN from the institute of Acoustic, Chinese academy of sciences₃₃The tester tests the polarized ceramic sample. As a result, as shown in FIG. 3, d at room temperature of a ceramic sample having a thickness of 0.6mm was measured₃₃=21 pC/N, the piezoelectric constant at room temperature was maintained at 300 degrees and the piezoelectric constant d at 500 degrees₃₃=20 pC/N。

The ceramic samples were tested with an impedance analyzer. As a result, as shown in FIG. 4, the resistivity of the ceramic sample at room temperature was measured to be 10⁹Omega. m, resistivity at 300 degrees of 8X 10⁷Ω · m, a resistivity at 500 degrees of 10⁵ Ω·m。

The ceramic samples were tested with an Agilent 4294A impedance analyzer. As a result, as shown in FIGS. 5 and 6, Kp and Kt of the ceramic sample at room temperature were 0.32 and 0.58, respectively, and Q was measured_m-Kp17.3, tan delta 4.5%.

The ferroelectric tester tests the ceramic samples. The results are shown in FIG. 7, and the residual polarization intensity of the ceramic sample at room temperature was measured to be 10.3. mu.C/cm²。

The data in combination with FIG. 3, FIG. 4, FIG. 5, FIG. 6, and FIG. 7 show that the piezoelectric constant and resistivity of CBT-0.4BFO ceramic are greater than those of Pure CBT ceramic at different temperatures. Residual polarization at room temperature, Kp, Kt, Q_m-KpGreater than Pure CBT ceramic and tan delta less than Pure CBT ceramic.

Claims (1)

1. The preparation method of the composite high-temperature piezoelectric ceramic material is characterized in that the composite high-temperature piezoelectric ceramic material comprises two-phase ceramic, wherein one phase is CaBi₄Ti₄O₁₅Ceramic, another phase is BiFeO₃Ceramics of the general formula CaBi₄Ti₄O₁₅-xBiFeO₃Wherein x is 0.2 to 0.4, the CaBi₄Ti₄O₁₅The ceramic is three-dimensional continuous layered ceramic, and the BiFeO₃Ceramic is dispersed in the CaBi₄Ti₄O₁₅The composite high-temperature piezoelectric ceramic material is a 0-3 type composite material at the grain boundary of ceramic, and comprises the following steps:

a) weighing BiFeO according to the composite high-temperature piezoceramic material₃Powder and CaBi₄Ti₄O₁₅Uniformly mixing the powder to obtain a mixture; the CaBi in step a)₄Ti₄O₁₅The preparation method of the powder comprises the following steps:

1) CaCO is prepared₃、Bi₂O₃And TiO₂Blending according to the molar ratio of 1:2:4 to be uniformly mixed;

2) sequentially drying, grinding and presintering the mixture obtained in the step 1) to obtain CaBi₄Ti₄O₁₅Powder, wherein the presintering temperature in the step 2) is 800 ℃, and the presintering time is 2 hours;

BiFeO in step a)₃The preparation method of the powder comprises the following steps:

3) bi is added₂O₃And Fe₂O₃According to the mol ratio of 1:1, burdening and uniformly mixing;

4) drying, grinding and presintering the mixture obtained in the step 3) to obtain BiFeO₃Powder, wherein the presintering temperature in the step 4) is 850 ℃, and the presintering time is 2 hours;

b) drying and grinding the mixture obtained in the step a) to obtain CaBi₄Ti₄O₁₅-xBiFeO₃Powder, wherein x is 0.2-0.4;

c) CaBi obtained in step b)₄Ti₄O₁₅-xBiFeO₃Polyvinyl alcohol accounting for 0.5wt% of the total weight of the powder is added into the powder to be used as a binder, and the mixture is ground again and pressed into a ceramic wafer; the diameter of the ceramic wafer in the step c) is 13mm, and the thickness of the ceramic wafer is 1 mm;

d) keeping the temperature of the ceramic wafer pressed in the step c) at 550 ℃ for 2 hours to remove the glue, then raising the temperature, and sintering at 650-950 ℃, wherein the heat preservation time is 1 hour;

e) brushing silver paste on the upper surface and the lower surface of the ceramic wafer fired in the step d), and preserving heat at 650 ℃ for 15 minutes to obtain a ceramic wafer with a silver electrode;

f) and placing the sintered ceramic sample with the silver electrode in methyl silicone oil, and polarizing by using a high-voltage electric field, wherein the polarizing electric field is 120kV/cm, and the polarizing time is 20-30 minutes, so as to obtain the composite high-temperature piezoelectric ceramic material.

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