A bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic and its preparation method
By introducing Al and Zr to replace Sc and Ti in the BS-PT system, and optimizing the composition and process, the problem of limited application of traditional lead zirconate titanate-based piezoelectric ceramics in high-temperature environments has been solved, achieving high voltage performance and low dielectric loss, and improving high-temperature stability and cost-effectiveness.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-26
- Publication Date
- 2026-03-17
AI Technical Summary
Traditional lead zirconate titanate-based piezoelectric ceramics have limited applications in high-temperature environments. Their low Curie temperature, high dielectric loss, and small mechanical quality factor restrict their application at high frequencies and high temperatures.
By introducing Al and Zr to replace Sc and Ti in the BS-PT system, an xBiSc1-zAlzO3-(1-x)PbZryTi1-yO3 composition system was constructed, optimizing the composition and process, reducing dielectric loss and improving piezoelectric performance.
The piezoelectric coefficient d33 was achieved in the range of 171–356 pC/N, the Curie temperature in the range of 346–398 °C, and the dielectric loss was reduced to 1.30%–1.60%. The piezoelectric properties of the material changed by less than 20% in the range of room temperature to 310 °C, which reduced costs and improved high-temperature stability.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of piezoelectric ceramic materials technology, and in particular to a bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic and its preparation method. Background Technology
[0002] Piezoelectric ceramics are functional materials capable of converting mechanical energy into electrical energy. Due to their excellent piezoelectric, dielectric, and ferroelectric properties, they are widely used in sensors, transducers, actuators, and energy harvesters. Therefore, researching and preparing high-performance piezoelectric materials will help promote the upgrading of scientific and technological industries.
[0003] Traditional commercial lead zirconate titanate (PZT)-based piezoelectric ceramics have been widely used in functional devices such as sensors, transducers, and actuators. However, the relatively low Curie temperature of PZT-based piezoelectric ceramics, reaching a maximum of approximately 380°C, severely limits their application in high-temperature environments. In recent years, numerous studies have discovered that the Curie temperature of the (1-x)BiScO3-xPbTiO3 (BS-PT) ceramic solid solution system can reach 450°C at its quasi-isomorphic phase boundary composition (x = 0.64), and the piezoelectric constant d... 33 While achieving a dielectric constant of 460 pC / N, BS-PT-based piezoelectric ceramics exhibit superior high-temperature performance. However, practical applications have revealed that the expensive raw material Sc2O3, coupled with the high dielectric loss and low mechanical quality factor of this pure-phase system, limits its application at high frequencies and temperatures. To meet the growing demands of daily life and production, further improving the stability of piezoelectric ceramics at high temperatures is crucial for broadening their application scope. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic and its preparation method. The bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic prepared by this invention has a piezoelectric coefficient d. 33 Within the range of 171–356 pC / N and the Curie temperature range of 346–398 °C, the dielectric loss at 1 kHz frequency at room temperature is reduced to 1.30%–1.60%, while the temperature stability of the system is improved, and the piezoelectric constant maintains a change rate of less than 20% in the range of room temperature to 310 °C.
[0005] The technical solution of the present invention is as follows:
[0006] The first aspect of this invention protects a bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material, wherein the general formula of the piezoelectric ceramic material is: xBiSc 1-z Al z O3-(1-x)PbZr y Ti 1-yO3, where 0.2≤x≤0.7, 0.3≤y≤0.6; 0.45≤z≤0.55.
[0007] The second aspect of this invention protects a method for preparing the bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material described in the first aspect above, the method comprising the following steps:
[0008] (1) Preparation of matrix powder
[0009] According to the stoichiometric ratio of the chemical components of the bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material, Bi2O3, Al2O3, Sc2O3, PbO, ZrO2, and TiO2 were weighed, mixed, ball-milled, dried, sieved, calcined, ball-milled again, and dried to obtain the matrix powder.
[0010] (2) Preparation of blank
[0011] Add polyvinyl alcohol aqueous solution to the matrix powder in step (1), granulate, and compact to obtain a green body;
[0012] (3) Preparation of the piezoelectric ceramic material
[0013] The blank obtained in step (2) is placed in a muffle furnace for debinding, cold isostatic pressing, and sintering to obtain the bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material.
[0014] Preferably, in step (1), the ball milling conditions are: the material-to-ball-to-water ratio is 1-1.5:2-3:1.5-3, the speed is 300-400 r / min, and the time for each ball milling is 12-24 h.
[0015] Preferably, in step (1), the mesh size of the sieve is 80 to 120 mesh.
[0016] Preferably, in step (1), the drying temperature is 80-100℃ and the drying time is 4-6h each time.
[0017] Preferably, in step (1), the heating and cooling rate of calcination is 4-6℃ / min, the calcination temperature is 700-800℃, and the holding time is 4-5h.
[0018] Preferably, in step (2), the mass concentration of the polyvinyl alcohol aqueous solution is 5-10 wt%, and the amount added is 3-5 mL of polyvinyl alcohol aqueous solution per 10 g of matrix powder.
[0019] Preferably, in step (2), the compaction pressure is 8 to 12 MPa.
[0020] Preferably, in step (3), the conditions for discharging the adhesive are: the heating and cooling rate is 1-2℃ / min, the discharging temperature is 550-620℃, and the heat preservation time is 2-4h;
[0021] And / or, the conditions for the cold isostatic pressing are: pressure of 100-140 MPa and holding time of 20-40 min.
[0022] Preferably, in step (3), the heating and cooling rate of the sintering is 4-6℃ / min, the temperature is 1150-1250℃, and the holding time is 2-4h.
[0023] The beneficial technical effects of this invention are as follows:
[0024] This invention constructs xBiSc by introducing certain amounts of Al and Zr into the BS-PT system to replace Sc and Ti at the B site, respectively. 1-z Al z O3-(1-x)PbZr y Ti 1-y In an O3-based system, where 0.2 ≤ x ≤ 0.7, 0.3 ≤ y ≤ 0.6, and 0.45 ≤ z ≤ 0.55, the dielectric loss of the material was reduced through composition control and process optimization, and the piezoelectric properties were relatively excellent (d 33 With a temperature of approximately 356 pC / N and a Curie temperature reaching 346℃, it has further promoted the development of high-temperature piezoelectric ceramics.
[0025] The preparation of piezoelectric ceramics in this invention reduces the cost of raw materials used, and the preparation process is simple, reproducible, and easy to operate. Attached Figure Description
[0026] Figure 1 The X-ray diffraction pattern is shown in the embodiment of the present invention for the ceramic material.
[0027] In the figure: (a) is the XRD pattern measured at room temperature, with a test range of 20° to 60°; (b) is a magnified view of a part at 43° to 46°.
[0028] Figure 2 The curve showing the change of dielectric constant with temperature for the ceramic material prepared according to an embodiment of the present invention.
[0029] In the figure: (a) Example 1; (b) Example 2; (c) Example 3; (d) Example 4.
[0030] Figure 3 The hysteresis loops are those of the ceramic materials obtained in Examples 1-4 of this invention.
[0031] Figure 4 The piezoelectric constant d of the materials in Embodiment 4 and Comparative Example 1 of this invention. 33 The variation of its normalized data with annealing temperature.
[0032] In the figure: (a) the piezoelectric constant changes with annealing temperature; (b) the rate of change of piezoelectric constant changes with annealing temperature. Detailed Implementation
[0033] The present invention will now be described in detail with reference to the embodiments.
[0034] A bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material, characterized in that the general formula of the piezoelectric ceramic material is: xBiSc 1-z Al z O3-(1-x)PbZr y Ti 1-y O3, where 0.2≤x≤0.7, 0.3≤y≤0.6; 0.45≤z≤0.55. Abbreviated as BAS-PZT.
[0035] It is understood that this invention constructs xBiSc by introducing a certain amount of Al and Zr into the BS-PT system to replace Sc and Ti at the B site, respectively. 1-z Al z O3-(1-x)PbZr y Ti 1-y In the O3 component system, where 0.2≤x≤0.7, 0.3≤y≤0.6, and 0.45≤z≤0.55, the dielectric loss of the material was reduced through component control and process optimization, and the piezoelectric properties were relatively excellent (d 33 With a temperature of approximately 356 pC / N and a Curie temperature of 346 °C, this invention further promotes the development of high-temperature piezoelectric ceramics. Specifically, by introducing more alumina into the Bi-based end-members of the BS-PT system, this invention can, on the one hand, reduce the amount of Sc2O3 used in the system, significantly reducing the preparation cost; on the other hand… and The large differences in ionic radii lead to significant changes in the lattice parameters of the Bi-based endmembers, exacerbating lattice distortion. This invention utilizes the lattice distortion caused by substitution to improve the low mechanical quality factor of pure BS-PT piezoelectric ceramic materials, resulting in less loss during high-temperature and high-frequency vibration, thereby improving the stability and service life of the materials.
[0036] In addition, the raw materials used in this invention contain alumina, which has the advantages of good thermal stability and low coefficient of thermal expansion. When the temperature rises, the atomic vibrations are relatively less intense, which can suppress the phase transformation process of ceramic materials caused by the temperature rise, thereby achieving excellent temperature stability of piezoelectric properties.
[0037] The present invention will be further described below with reference to the embodiments.
[0038] Example 1:
[0039] A bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material 0.2BiSc 0.45 Al 0.55 O3-0.8PbZr 0.5 Ti 0.5 O3 is prepared by the following steps:
[0040] (1) Preparation of matrix powder
[0041] According to 0.2BiSc 0.45 Al 0.55 O3-0.8PbZr 0.5 Ti 0.5 The stoichiometric ratio of O3 was determined by weighing Bi2O3, Al2O3, Sc2O3, PbO, ZrO2, and TiO2, mixing them, ball milling for 24 hours, drying in an oven at 100℃ for 4 hours, grinding the mixture into a uniform powder using a pestle, sieving it through an 80-mesh sieve, placing it in a muffle furnace, calcining it at 800℃ at a rate of 5℃ / min and holding it at that temperature for 4 hours, then ball milling the calcined powder again for 24 hours, and finally drying it in an oven at 100℃ to obtain the matrix powder. The ball milling conditions were: a material-to-ball-to-water ratio of 1:2:1.5 and a milling speed of 300 r / min.
[0042] (2) Preparation of blank
[0043] Add 4 mL of 7wt% polyvinyl alcohol aqueous solution per 10 g of powder to the matrix powder obtained in step (1), place it in a mortar, and then use a pestle to fully mix the powder and binder and grind it until the powder is fine, the particle size is uniform, and the flowability is good. After granulation, press it into a cylindrical blank with a diameter of 10 mm and a thickness of 1 mm under a pressure of 10 MPa.
[0044] (3) Preparation of the piezoelectric ceramic material
[0045] The blank obtained in step (2) is placed in a muffle furnace for debinding, cold isostatic pressing, and sintering to obtain the bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material.
[0046] The process conditions for debinding are as follows: heating and cooling rate is 2℃ / min, debinding temperature is 600℃, and holding time is 3h; the conditions for cold isostatic pressing are: pressure is 120MPa, holding time is 30min; and the process conditions for sintering are: heating and cooling rate is 5℃ / min, sintering temperature is 1200℃, and holding time is 2h.
[0047] To reduce the excessive volatilization of Bi and Pb elements in the system, the green body is embedded with powder of the same composition before sintering.
[0048] Example 2:
[0049] A bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material 0.25BiSc 0.45 Al 0.55 O3-0.75PbZr 0.45 Ti 0.55 O3 is prepared by the following steps:
[0050] (1) Preparation of matrix powder
[0051] According to 0.25BiSc 0.45 Al 0.55 O3-0.75PbZr 0.45 Ti 0.55 The stoichiometric ratio of O3 was determined by weighing Bi2O3, Al2O3, Sc2O3, PbO, ZrO2, and TiO2, mixing them, ball milling for 24 hours, drying in an oven at 100℃ for 4 hours, grinding the mixture into a uniform powder using a pestle, sieving it through an 80-mesh sieve, placing it in a muffle furnace, calcining it at 800℃ at a rate of 5℃ / min and holding it at that temperature for 4 hours, then ball milling the calcined powder again for 24 hours, and finally drying it in an oven at 100℃ to obtain the matrix powder. The ball milling conditions were: a material-to-ball-to-water ratio of 1:2:1.5 and a milling speed of 300 r / min.
[0052] (2) Preparation of blank
[0053] Add 4 mL of 7wt% polyvinyl alcohol aqueous solution per 10 g of powder to the matrix powder obtained in step (1), place it in a mortar, and then use a pestle to fully mix the powder and binder and grind it until the powder is fine, the particle size is uniform, and the flowability is good. After granulation, press it into a cylindrical blank with a diameter of 10 mm and a thickness of 1 mm under a pressure of 10 MPa.
[0054] (3) Preparation of the piezoelectric ceramic material
[0055] The blank obtained in step (2) is placed in a muffle furnace for debinding, cold isostatic pressing, and sintering to obtain the bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material.
[0056] The process conditions for debinding are as follows: heating and cooling rate is 2℃ / min, debinding temperature is 600℃, and holding time is 3h; the conditions for cold isostatic pressing are: pressure is 120MPa, holding time is 30min; and the process conditions for sintering are: heating and cooling rate is 5℃ / min, sintering temperature is 1200℃, and holding time is 2h.
[0057] To reduce the excessive volatilization of Bi and Pb elements in the system, the green body is embedded with powder of the same composition before sintering.
[0058] Example 3:
[0059] A bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material 0.3BiSc 0.45 Al 0.55 O3-0.7PbZr 0.45 Ti 0.55 A method for preparing O3, the method comprising the following steps:
[0060] (1) Preparation of matrix powder
[0061] According to 0.3BiSc 0.45 Al 0.55 O3-0.7PbZr 0.45 Ti 0.55 The stoichiometric ratio of O3 was determined by weighing Bi2O3, Al2O3, Sc2O3, PbO, ZrO2, and TiO2, mixing them, ball milling for 24 hours, drying in an oven at 100℃ for 4 hours, grinding the mixture into a uniform powder using a pestle, sieving it through an 80-mesh sieve, placing it in a muffle furnace, calcining it at 800℃ at a rate of 5℃ / min and holding it at that temperature for 4 hours, then ball milling the calcined powder again for 24 hours, and finally drying it in an oven at 100℃ to obtain the matrix powder. The ball milling conditions were: a material-to-ball-to-water ratio of 1:2:1.5 and a milling speed of 300 r / min.
[0062] (2) Preparation of blank
[0063] Add 4 mL of 7wt% polyvinyl alcohol aqueous solution per 10 g of powder to the matrix powder obtained in step (1), place it in a mortar, and then use a pestle to fully mix the powder and binder and grind it until the powder is fine, the particle size is uniform, and the flowability is good. After granulation, press it into a cylindrical blank with a diameter of 10 mm and a thickness of 1 mm under a pressure of 10 MPa.
[0064] (3) Preparation of the piezoelectric ceramic material
[0065] The blank obtained in step (2) is placed in a muffle furnace for debinding, cold isostatic pressing, and sintering to obtain the bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material.
[0066] The process conditions for debinding are as follows: heating and cooling rate is 2℃ / min, debinding temperature is 600℃, and holding time is 3h; the conditions for cold isostatic pressing are: pressure is 120MPa, holding time is 30min; and the process conditions for sintering are: heating and cooling rate is 5℃ / min, sintering temperature is 1200℃, and holding time is 2h.
[0067] To reduce the excessive volatilization of Bi and Pb elements in the system, the green body is embedded with powder of the same composition before sintering.
[0068] Example 4:
[0069] A bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material 0.25BiSc 0.45 Al 0.55 O3-0.75PbZr 0.35 Ti 0.65 A method for preparing O3, the method comprising the following steps:
[0070] (1) Preparation of matrix powder
[0071] According to 0.25BiSc 0.45 Al 0.55 O3-0.75PbZr 0.35 Ti 0.65 The stoichiometric ratio of O3 was determined by weighing Bi2O3, Al2O3, Sc2O3, PbO, ZrO2, and TiO2, mixing them, ball milling for 24 hours, drying in an oven at 100℃ for 4 hours, grinding the mixture into a uniform powder using a pestle, sieving it through an 80-mesh sieve, placing it in a muffle furnace, calcining it at 800℃ at a rate of 5℃ / min and holding it at that temperature for 4 hours, then ball milling the calcined powder again for 24 hours, and finally drying it in an oven at 100℃ to obtain the matrix powder. The ball milling conditions were: a material-to-ball-to-water ratio of 1:2:1.5 and a milling speed of 300 r / min.
[0072] (2) Preparation of blank
[0073] Add 4 mL of 7wt% polyvinyl alcohol aqueous solution per 10 g of powder to the matrix powder obtained in step (1), place it in a mortar, and then use a pestle to fully mix the powder and binder and grind it until the powder is fine, the particle size is uniform, and the flowability is good. After granulation, press it into a cylindrical blank with a diameter of 10 mm and a thickness of 1 mm under a pressure of 10 MPa.
[0074] (3) Preparation of the piezoelectric ceramic material
[0075] The blank obtained in step (2) is placed in a muffle furnace for debinding, cold isostatic pressing, and sintering to obtain the bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material.
[0076] The process conditions for debinding are as follows: heating and cooling rate is 2℃ / min, debinding temperature is 600℃, and holding time is 3h; the conditions for cold isostatic pressing are: pressure is 120MPa, holding time is 30min; and the process conditions for sintering are: heating and cooling rate is 5℃ / min, sintering temperature is 1200℃, and holding time is 2h.
[0077] To reduce the excessive volatilization of Bi and Pb elements in the system, the green body is embedded with powder of the same composition before sintering.
[0078] Example 5
[0079] A bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material 0.2BiSc 0.45 Al 0.55 O3-0.8PbZr 0.5 Ti 0.5 O3 is prepared by the following steps:
[0080] (1) Preparation of matrix powder
[0081] According to 0.2BiSc 0.45 Al 0.55 O3-0.8PbZr 0.5 Ti 0.5 The stoichiometric ratio of O3 was determined by weighing Bi2O3, Al2O3, Sc2O3, PbO, ZrO2, and TiO2, mixing them, ball milling for 12 hours, drying in an oven at 80℃ for 6 hours, grinding the mixture into a uniform powder using a pestle, sieving it through a 100-mesh sieve, placing it in a muffle furnace, calcining it at 700℃ at a rate of 4℃ / min and holding it at that temperature for 4.5 hours, then ball milling the calcined powder again for 12 hours, and finally drying it in an oven at 80℃ to obtain the matrix powder. The ball milling conditions were: a material-to-ball-to-water ratio of 1.2:2.5:2.0 and a milling speed of 350 r / min.
[0082] (2) Preparation of blank
[0083] Add 3 mL of 5 wt% polyvinyl alcohol aqueous solution per 10 g of powder to the matrix powder obtained in step (1), place it in a mortar, and then use a pestle to fully mix the powder and binder and grind it until the powder is fine, the particle size is uniform, and the fluidity is good. After granulation, press it into a cylindrical blank with a diameter of 10 mm and a thickness of 1 mm under a pressure of 8 MPa.
[0084] (3) Preparation of the piezoelectric ceramic material
[0085] The blank obtained in step (2) is placed in a muffle furnace for debinding, cold isostatic pressing, and sintering to obtain the bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material.
[0086] The process conditions for debinding are as follows: heating and cooling rate is 1℃ / min, debinding temperature is 550℃, and holding time is 2h; the conditions for cold isostatic pressing are: pressure is 100MPa, holding time is 20min; the process conditions for sintering are: heating and cooling rate is 4℃ / min, sintering temperature is 1150℃, and holding time is 3h.
[0087] To reduce the excessive volatilization of Bi and Pb elements in the system, the green body is embedded with powder of the same composition before sintering.
[0088] Example 6
[0089] A bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material 0.2BiSc 0.45 Al 0.55 O3-0.8PbZr 0.5 Ti 0.5 O3 is prepared by the following steps:
[0090] (1) Preparation of matrix powder
[0091] According to 0.2BiSc 0.45 Al 0.55 O3-0.8PbZr 0.5 Ti 0.5 The stoichiometric ratio of O3 was determined by weighing Bi2O3, Al2O3, Sc2O3, PbO, ZrO2, and TiO2, mixing them, ball milling for 20 hours, drying in a 90℃ oven for 5 hours, grinding the mixture into a uniform powder using a pestle, sieving it through a 120-mesh sieve, placing it in a muffle furnace, calcining it at 750℃ at a rate of 6℃ / min and holding it at that temperature for 5 hours, then ball milling the calcined powder again for 20 hours, and finally drying it in a 90℃ oven to obtain the matrix powder. The ball milling conditions were: a material-to-ball-to-water ratio of 1.5:3:3 and a milling speed of 400 r / min.
[0092] (2) Preparation of blank
[0093] Add 5 mL of 10 wt% polyvinyl alcohol aqueous solution per 10 g of powder to the matrix powder obtained in step (1), place it in a mortar, and then use a pestle to fully mix the powder and binder and grind it until the powder is fine, the particle size is uniform, and the flowability is good. After granulation, press it into a cylindrical blank with a diameter of 10 mm and a thickness of 1 mm under a pressure of 12 MPa.
[0094] (3) Preparation of the piezoelectric ceramic material
[0095] The blank obtained in step (2) is placed in a muffle furnace for debinding, cold isostatic pressing, and sintering to obtain the bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic material.
[0096] The process conditions for debinding are as follows: heating and cooling rate is 1.5℃ / min, debinding temperature is 620℃, and holding time is 4h; the conditions for cold isostatic pressing are: pressure is 140MPa, holding time is 40min; and the process conditions for sintering are: heating and cooling rate is 6℃ / min, sintering temperature is 1250℃, and holding time is 4h.
[0097] To reduce the excessive volatilization of Bi and Pb elements in the system, the green body is embedded with powder of the same composition before sintering.
[0098] Comparative Example 1:
[0099] A bismuth scandate-lead titanate based piezoelectric ceramic material with a strength of 0.36BS-0.64PT is prepared by the following steps:
[0100] (1) Preparation of matrix powder
[0101] According to the stoichiometric ratio of 0.36BS-0.64PT, Bi₂O₃, Sc₂O₃, PbO, and TiO₂ were weighed, mixed, and ball-milled for 24 hours. After drying in an oven at 100℃ for 4 hours, the mixture was ground into a uniform powder using a pestle. The powder was then sieved through an 80-mesh sieve and placed in a muffle furnace. The temperature was increased to 800℃ at a rate of 5℃ / min and held for 4 hours. The calcined powder was then ball-milled again for 24 hours and dried in an oven at 100℃ to obtain the desired matrix powder. The ball-milling conditions were: a material-to-ball-to-water ratio of 1:2:1.5 and a milling speed of 300 r / min.
[0102] (2) Preparation of blank
[0103] Add 4 mL of 7wt% polyvinyl alcohol aqueous solution per 10 g of powder to the powder obtained in step (1), place it in a mortar, and then use a pestle to fully mix the powder and binder and grind it until the powder is fine, the particle size is uniform, and the flowability is good. After granulation, press it into a cylindrical blank with a diameter of 10 mm and a thickness of 1 mm under a pressure of 10 MPa.
[0104] (3) Preparation of the piezoelectric ceramic material
[0105] The blank obtained in step (2) is placed in a muffle furnace for debinding, cold isostatic pressing, and sintering to obtain the bismuth scandate-lead titanate-based piezoelectric ceramic material.
[0106] The process conditions for debinding are as follows: heating and cooling rate is 2℃ / min, debinding temperature is 600℃, and holding time is 3h; the conditions for cold isostatic pressing are: pressure is 120MPa, holding time is 30min; and the process conditions for sintering are: heating and cooling rate is 5℃ / min, sintering temperature is 1000℃, and holding time is 2h.
[0107] To reduce the excessive volatilization of Bi and Pb elements in the system, the green body is embedded with powder of the same composition before sintering.
[0108] Test example:
[0109] The piezoelectric ceramic materials prepared in the above examples and comparative examples were polished, electrode-attached, and polarized. The polarization electric field was 40-50 kV / cm, the polarization time was 20 min, and the polarization temperature was 120℃. The dielectric loss of the polarized sample at 1 kHz frequency at room temperature was measured using a 4294A impedance analyzer, and the piezoelectric properties of the polarized sample were measured using a quasi-static d33 meter. The dielectric temperature spectrum of the material was measured using a Linkam variable temperature system coupled with an HP 4284A. The comprehensive performance is shown in Table 1 below.
[0110] Table 1 Performance tests of the examples and comparative examples
[0111]
[0112] As shown in the table above, the bismuth scandium aluminate-lead zirconate titanate piezoelectric ceramic of the embodiment exhibits a piezoelectric coefficient of 356 pC / N, a Curie temperature of 346 °C, and a dielectric loss of 1.60% at 1 kHz room temperature. Although the piezoelectric coefficient and Curie temperature of the comparative example are improved, its dielectric loss is more than twice that of the embodiment, and its mechanical quality factor Qm is much smaller than that of the embodiment, which greatly limits its high-temperature stability. Consequently, the depolarization behavior of the comparative example is more likely to occur than that of the embodiment. The ceramic material of the present invention achieves the largest possible piezoelectric coefficient and Curie temperature while reducing dielectric loss and improving high-temperature stability.
[0113] Figure 1 The X-ray diffraction pattern is shown in the embodiment of the present invention for the ceramic material. Figure 1 (a) XRD patterns of the ceramic materials in each embodiment and comparative example, measured at room temperature, 0.2 BAS-0.8 PZ. 0.5 T 0.5 Corresponding to Example 1; 0.25BAS-0.75PZ 0.45 T 0.55 Corresponding to Example 2; 0.3BAS-0.7PZ 0.45 T 0.55 Corresponding to Example 3; 0.25BAS-0.75PZ 0.35 T 0.65 Corresponding to Example 4; the test range is 20° to 60°. Figure 1 (b) is a magnified view at 44°–46°. According to Example 4 in Figure b, i.e., 0.25BAS–0.75PZ. 0.35 T 0.65 The splitting of the (200) peak in the component ceramic shows that the crystal phase structure is mainly composed of trigonal and tetragonal phases. The phase structure of the system is at the quasi-isomorphic phase boundary, so the piezoelectric performance of this system is optimal.
[0114] Figure 2The figures show the dielectric constant and dielectric loss of the ceramic materials prepared in Examples 1-4 of this invention as a function of temperature at frequencies of 1kHz, 10kHz, 100kHz, and 500kHz. As can be seen from the figures, the Curie temperatures of the piezoelectric ceramics with different compositions differ greatly, but the corresponding dielectric losses are all relatively small, which is beneficial for their application at high temperatures.
[0115] Figure 3 The hysteresis loops of the ceramic materials prepared in the embodiments of the present invention are shown. By comparison, it can be seen that the sample in Example 4 has the largest residual polarization intensity, and the corresponding system has the best piezoelectric performance.
[0116] This invention annealed ceramic materials with different compositions to test the high-temperature stability of piezoelectric ceramic materials. After polarization, the piezoelectric ceramics of the examples and comparative examples were annealed in muffle furnaces at different temperatures for 1 hour, and then cooled to room temperature to measure the d-values of the materials. 33 The specific results are as follows: Figure 4 As shown in the figure, the piezoelectric constant of the Comparative Example 1 sample decreases rapidly with increasing annealing temperature, and its piezoelectric property change rate is less than 20% in the temperature range from room temperature to 275°C, while that of Example 4 (0.25BAS-0.75PZ) is significantly higher. 0.35 T 0.65 The temperature stability of the system is greatly improved, and its piezoelectric properties change by less than 20% in the temperature range from room temperature to 310℃, showing better prospects for high-temperature applications.
[0117] This invention introduces a certain amount of Al and Zr into the BS-PT system to replace Sc and Ti at the B site, respectively. On the one hand, this reduces the amount of Sc2O3 used in the system, greatly reducing the preparation cost. On the other hand, it utilizes the lattice distortion caused by ion substitution to improve the dielectric loss of the material, thereby improving the stability and service life of the material.
[0118] The above description is merely a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations that are directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.
Claims
1. A bismuth scandium tantalate-lead zirconate titanate piezoelectric ceramic material, characterized by, The piezoelectric ceramic material has a general formula: xBiSc 1-z Al z O3-(1-x)PbZr y Ti 1-y O3, wherein 0.2≤x≤0.7, 0.3≤y≤0.6; 0.45≤z≤0.
55. The preparation method of the scandium bismuth aluminate-lead zirconate titanate piezoelectric ceramic material comprises the following steps: (1) preparing a base powder According to the chemical component measurement ratio of the scandium bismuth aluminate-lead zirconate titanate piezoelectric ceramic material, Bi2O3, Al2O3, Sc2O3, PbO, ZrO2 and TiO2 are weighed and mixed, then ball-milled, dried, sieved, calcined, ball-milled again, dried, and the base powder is obtained; (2) preparing a green body Polyvinyl alcohol aqueous solution is added to the base powder of step (1), granulated, and compacted to obtain a green body; (3) preparing the piezoelectric ceramic material The green body obtained in step (2) is placed in a muffle furnace for degassing, cold isostatic pressing and sintering to obtain the scandium bismuth aluminate-lead zirconate titanate piezoelectric ceramic material.
2. The bismuth scandium tantalate-lead zirconate titanate piezoelectric ceramic material of claim 1, wherein, In step (1), the ball-milling conditions are as follows: the ratio of material ball to water is 1-1.5:2-3:1.5-3, and the speed is 300-400 r / min; the ball-milling time is 12-24 h each time.
3. The bismuth scandium tantalate-lead zirconate titanate piezoelectric ceramic material of claim 1, wherein, In step (1), the mesh size of the sieve is 80-120 mesh.
4. The bismuth scandium tantalate-lead zirconate titanate piezoelectric ceramic material of claim 1, wherein, In step (1), the drying temperature is 80-100℃ each time, and the time is 4-6 h.
5. The bismuth scandium tantalate-lead zirconate titanate piezoelectric ceramic material of claim 1, wherein, In step (1), the calcination temperature is 700-800℃, the temperature rising and falling rate is 4-6℃ / min, and the holding time is 4-5 h.
6. The bismuth scandium tantalate-lead zirconate titanate piezoelectric ceramic material of claim 1, wherein, In step (2), the mass concentration of the polyvinyl alcohol aqueous solution is 5-10 wt%, and the addition amount is 3-5 mL of polyvinyl alcohol aqueous solution per 10 g of base powder.
7. The bismuth scandium tantalate-lead zirconate titanate piezoelectric ceramic material of claim 1, wherein, In step (2), the compaction pressure is 8-12 MPa.
8. The bismuth scandium tantalate-lead zirconate titanate piezoelectric ceramic material of claim 1, wherein, In step (3), the degassing conditions are as follows: the temperature rising and falling rate is 1-2℃ / min, the degassing temperature is 550-620℃, and the holding time is 2-4 h; And / or, the cold isostatic pressing conditions are as follows: the pressure is 100-140 MPa, and the holding time is 20-40 min.
9. The bismuth scandium tantalate-lead zirconate titanate piezoelectric ceramic material of claim 1, wherein, In step (3), the sintering temperature is 1150-1250℃, the temperature rising and falling rate is 4-6℃ / min, and the holding time is 2-4 h.