Porous piezoelectric ceramic material and preparation method thereof, porous piezoelectric ceramic material intermediate product and piezoelectric device

Abstract

The invention relates to a porous piezoelectric ceramic material and a preparation method thereof, a porous piezoelectric ceramic material intermediate product and a piezoelectric device. The chemical general formula of the porous piezoelectric ceramic material is as follows: 0.45 Pb (Ni < 1 / 3 > Nb < 2 / 3 >) O < 3 >-0.20 PbZrO < 3 >-0.35 PbTiO < 3 >. According to the technical scheme, the porous piezoelectric ceramic material is of a porous structure, PZT serves as a matrix, PNN is introduced to serve as a third component, and the piezoelectric property of pure PZT is improved. Experiments prove that the porous piezoelectric ceramic material provided by the technical scheme of the invention can maintain excellent piezoelectric property while realizing low acoustic impedance, and is beneficial to wide application.

Description

Technical Field

[0001] The present invention relates to the technical field of piezoelectric ceramics, and in particular to a porous piezoelectric ceramic material and a preparation method thereof, a porous piezoelectric ceramic material intermediate product and a piezoelectric device. Background Art

[0002] Porous piezoelectric ceramics belong to piezoelectric composite materials (piezoelectric phase / air) and can be used in piezoelectric hydroacoustic transducers. Piezoelectric hydroacoustic transducers are divided into two categories: transducers that convert electrical signals into hydroacoustic signals with the help of the piezoelectric effect, which are used to radiate sound waves into the water, are called transmitting transducers. Transducers that convert acoustic signals into electrical signals with the help of the piezoelectric effect, which are used to receive acoustic signals in the water, are called receiving transducers, also known as hydrophones. However, the low acoustic impedance and high voltage electrical performance of traditional porous piezoelectric ceramics cannot be taken into account at the same time, which is not conducive to widespread application. Summary of the invention

[0003] Based on this, it is necessary to provide a porous piezoelectric ceramic material and a preparation method thereof, a porous piezoelectric ceramic material intermediate product and a piezoelectric device in order to solve the problem of how to achieve low acoustic impedance while maintaining excellent piezoelectric performance.

[0004] A porous piezoelectric ceramic material, the chemical formula of the porous piezoelectric ceramic material is: 0.45Pb(Ni 1 / 3Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3.

[0005] The porous piezoelectric ceramic material of the technical solution of the present invention is a porous structure, with PZT as the matrix and PNN as the third component, which improves the piezoelectric performance of pure PZT. After experimental verification, the porous piezoelectric ceramic material of the technical solution of the present invention can achieve low acoustic impedance while maintaining excellent piezoelectric performance, which is conducive to wide application.

[0006] In a feasible implementation, the acoustic impedance of the porous piezoelectric ceramic material is 33 MRayl to 16 MRayl, and the piezoelectric coefficient d of the porous piezoelectric ceramic material is 33 The porosity of the porous piezoelectric ceramic material is 6% to 27%.

[0007] A porous piezoelectric ceramic material intermediate product, the chemical formula of the porous piezoelectric ceramic material intermediate product is: 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+x wt%PMMA, wherein 0<x≤15.

[0008] The porous piezoelectric ceramic material intermediate product of the technical solution of the present invention uses PZT as the matrix and introduces PNN as the third component, which improves the piezoelectric properties of pure PZT; in addition, the above intermediate product includes a pore-forming agent PMMA, which is used to obtain a porous piezoelectric ceramic material with excellent pore shape, which is conducive to achieving low acoustic impedance. After experimental verification, the porous piezoelectric ceramic material intermediate product of the technical solution of the present invention can obtain a porous piezoelectric ceramic material with low acoustic impedance and high piezoelectric performance, which is conducive to wide application. For example, it is expected to be used in the fields of underwater acoustic transducers and air transducers.

[0009] In a feasible implementation, the size of the PMMA is 1 μm to 20 μm.

[0010] A method for preparing a porous piezoelectric ceramic material comprises the following steps:

[0011] Based on the chemical formula 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3 stoichiometric ratio, PbO powder, NiO powder, Nb2O5 powder, ZrO2 powder, Bi2O3 powder and TiO2 powder are uniformly mixed, and then pre-sintered to obtain ceramic powder after sufficient reaction;

[0012] The ceramic powder is mixed evenly with polymethyl methacrylate, wherein the mass fraction of the polymethyl methacrylate is x wt%, wherein 0<x≤15, to obtain a porous piezoelectric ceramic material intermediate product;

[0013] Granulating the porous piezoelectric ceramic material intermediate product, and then pressing and molding to obtain a ceramic green sheet; and

[0014] The ceramic green sheet is subjected to debonding and sintering treatment to obtain a porous piezoelectric ceramic material.

[0015] The preparation method of the porous piezoelectric ceramic material of the technical solution of the present invention is simple and easy, low in cost, and can be mass-produced. The porous piezoelectric ceramic material prepared by the above preparation method has a porous structure, with PZT as the matrix and PNN as the third component, which improves the piezoelectric properties of pure PZT. After experimental verification, the porous piezoelectric ceramic material of the technical solution of the present invention can achieve low acoustic impedance while maintaining excellent piezoelectric properties, which is conducive to wide application.

[0016] In a feasible implementation, the temperature of the pre-sintering treatment is 700° C. to 900° C., and the time of the pre-sintering treatment is 1.5 h to 4 h.

[0017] In a feasible implementation, the size of the ceramic powder is less than 0.2 mm; the size of the polymethyl methacrylate is 1 μm to 20 μm.

[0018] In a feasible implementation, the granulation operation is: uniformly mixing the porous piezoelectric ceramic material intermediate product with a binder, and then passing through an 80-mesh sieve; wherein the mass percentage of the binder is 6% to 10%.

[0019] In a feasible implementation, the temperature of the debonding is 350°C to 630°C, and the heat preservation time of the debonding is 4h to 6h;

[0020] The sintering temperature is 1150° C. to 1270° C., and the sintering heat preservation time is 2 h to 4 h.

[0021] A piezoelectric device comprises the porous piezoelectric ceramic material mentioned above or a porous piezoelectric ceramic material prepared by any of the methods for preparing the porous piezoelectric ceramic material mentioned above.

[0022] The piezoelectric device of the technical solution of the present invention includes the above-mentioned porous piezoelectric ceramic material. The porous piezoelectric ceramic material is a porous structure, with PZT as the matrix and PNN introduced as the third component. It can achieve low acoustic impedance while maintaining excellent piezoelectric performance, which is conducive to wide application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flow chart of a method for preparing a porous piezoelectric ceramic material according to an embodiment of the present invention;

[0024] Figure 2 This is a cross-sectional SEM characterization image of the porous piezoelectric ceramic material obtained in Example 3 of the present invention. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0027] The general chemical formula of the porous piezoelectric ceramic material in one embodiment is: 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3. The porous piezoelectric ceramic material of this embodiment is a porous lead nickel niobate-lead zirconate titanate piezoelectric ceramic material.

[0028] On the basis of the above-mentioned implementation mode, the acoustic impedance of the porous piezoelectric ceramic material is 33 MRayl to 16 MRayl, and the piezoelectric coefficient d of the porous piezoelectric ceramic material is 33 The porous piezoelectric ceramic material has a porosity of 6% to 27%. In this case, the porous piezoelectric ceramic material of this embodiment can achieve low acoustic impedance while maintaining excellent piezoelectric performance.

[0029] The porous piezoelectric ceramic material of the technical solution of the present invention is a porous structure, with PZT as the matrix and PNN as the third component, which improves the piezoelectric performance of pure PZT. After experimental verification, the porous piezoelectric ceramic material of the technical solution of the present invention can achieve low acoustic impedance while maintaining excellent piezoelectric performance, which is conducive to wide application.

[0030] The chemical formula of the porous piezoelectric ceramic material intermediate product in one embodiment is: 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+x wt%PMMA, wherein 0<x≤15. Among them, the Chinese name of PMMA is polymethyl methacrylate, and the foreign name is Polymethyl Methacrylate. Among them, the role of PMMA is a pore-forming agent. PMMA is spherical and has a relatively regular shape, which is conducive to forming porous pores with better pore shape, thereby facilitating the acquisition of a porous piezoelectric ceramic material with low acoustic impedance and high piezoelectric performance. In the porous piezoelectric ceramic material intermediate product of this embodiment, the mass fraction of PMMA is greater than 0 and less than or equal to 15wt%. Furthermore, the mass fraction of PMMA can be but is not limited to 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt% or 15wt%.

[0031] On the basis of the above-mentioned embodiment, the size of PMMA is 1 μm to 20 μm. Further, the size of PMMA can be, but is not limited to, 1 μm, 1.8 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm.

[0032] The porous piezoelectric ceramic material intermediate product of the technical solution of the present invention uses PZT as the matrix and introduces PNN as the third component, which improves the piezoelectric properties of pure PZT; in addition, the above intermediate product includes a pore-forming agent PMMA, which is used to obtain a porous piezoelectric ceramic material with excellent pore shape, which is conducive to achieving low acoustic impedance. After experimental verification, the porous piezoelectric ceramic material intermediate product of the technical solution of the present invention can obtain a porous piezoelectric ceramic material with low acoustic impedance and high piezoelectric performance, which is conducive to a wide range of applications. For example, it is expected to be used in fields such as underwater acoustic transducers and air transducers.

[0033] See also Figure 1 A method for preparing a porous piezoelectric ceramic material according to an embodiment of the present invention comprises the following steps:

[0034] S10, based on the chemical formula 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3 stoichiometric ratio, PbO powder, NiO powder, Nb2O5 powder, ZrO2 powder, Bi2O3 powder and TiO2 powder are uniformly mixed, and then pre-sintered to obtain ceramic powder after sufficient reaction.

[0035] In step S10, the operation of uniformly mixing PbO powder, NiO powder, Nb2O5 powder, ZrO2 powder, Bi2O3 powder and TiO2 powder is as follows: put PbO powder, NiO powder, Nb2O5 powder, ZrO2 powder, Bi2O3 powder and TiO2 powder into a ball mill, pour in anhydrous ethanol, put the ball mill into a planetary ball mill, ball mill at a speed of 200r / min~400r / min for 12h~20h, and obtain a mixed powder after drying.

[0036] In a feasible implementation, the pre-sintering temperature is 700°C to 900°C, and the pre-sintering time is 1.5h to 4h. During pre-sintering, the heating rate is controlled at 3°C / min to 5°C / min. The pre-sintered ceramic powder is placed in a ball mill and anhydrous ethanol is added. The ball mill is milled at a speed of 200r / min to 400r / min for 12h to 20h to obtain a slurry; the slurry is dried and the dried powder is ground and crushed and passed through an 80-mesh sieve to obtain a ceramic powder.

[0037] In a feasible implementation, the size of the ceramic powder is less than 0.2 mm.

[0038] S20, uniformly mixing the ceramic powder obtained in step S10 with polymethyl methacrylate, wherein the mass fraction of polymethyl methacrylate is x wt%, where 0<x≤15, to obtain a porous piezoelectric ceramic material intermediate product.

[0039] In step S20, the operation of uniformly mixing the ceramic powder obtained in step S10 with polymethyl methacrylate is as follows: the ceramic powder obtained in step S10 and polymethyl methacrylate are mixed and ball-milled at a ball-milling speed of 100 r / min to 200 r / min for 2 h to 4 h, and a porous piezoelectric ceramic material intermediate product is obtained after drying.

[0040] In step S20, the mass fraction of polymethyl methacrylate is greater than 0 and less than or equal to 15wt%. Further, the mass fraction of PMMA can be but is not limited to 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt% or 15wt%.

[0041] In step S20, the size of the polymethyl methacrylate is 1 μm to 20 μm. Further, the size of the polymethyl methacrylate may be, but is not limited to, 1 μm, 1.8 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm.

[0042] S30, granulating the porous piezoelectric ceramic material intermediate product obtained in step S20, and then pressing and molding to obtain a ceramic green sheet.

[0043] In a feasible implementation, the granulation operation is: the porous piezoelectric ceramic material intermediate product is mixed with the binder evenly, and then passed through an 80-mesh sieve; wherein the mass percentage of the binder is 6% to 10%. wherein the powder size after passing through the 80-mesh sieve is less than 0.2 mm, and the mass percentage of the binder is the mass percentage of the binder relative to the pre-fired powder. further, the binder is polyvinyl alcohol (PVA).

[0044] In a feasible implementation, the operation of pressing and forming is: pressing the ceramic green sheet under a pressure of 2MPa to 5MPa. The diameter of the ceramic green sheet can be, but is not limited to, 10mm.

[0045] S40, debonding and sintering the ceramic green sheet obtained in step S30 to obtain a porous piezoelectric ceramic material.

[0046] In step S40 , the pore former can be ablated through a sintering process to form pores in the piezoelectric ceramic material.

[0047] In a feasible implementation, the temperature of debonding is 350° C. to 630° C., and the holding time of debonding is 4 h to 6 h; the temperature of sintering is 1150° C. to 1270° C., and the holding time of sintering is 2 h to 4 h.

[0048] Furthermore, after the porous piezoelectric ceramic material is prepared, it can be further polished and electrode-plated to obtain the porous piezoelectric ceramic, wherein the electrode-plated electrode can be, for example, a silver-plated electrode.

[0049] In a feasible implementation, the diameter of the silver-plated electrodes on the upper and lower surfaces of the ceramic sheet is 30 mm to 40 mm; the silver burning method is adopted, the silver burning temperature is 600° C. to 650° C., and the insulation time is 20 min to 30 min.

[0050] The preparation method of the porous piezoelectric ceramic material of the technical solution of the present invention is simple and easy, low in cost, and can be mass-produced. The porous piezoelectric ceramic material prepared by the above preparation method has a porous structure, with PZT as the matrix and PNN as the third component, which improves the piezoelectric properties of pure PZT. After experimental verification, the porous piezoelectric ceramic material of the technical solution of the present invention can achieve low acoustic impedance while maintaining excellent piezoelectric properties, which is conducive to wide application.

[0051] The present invention can make the porous lead nickel niobate-lead zirconate titanate piezoelectric ceramics have an adjustable acoustic impedance within the range of 33 MRayl to 16 MRayl by selecting an appropriate x value and the size of the PMMA pore-forming agent and controlling the process. 33 Maintained at 554pC / N~732pC / N, which is comparable to the d of dense lead nickel niobate-lead zirconate titanate piezoelectric ceramics. 33 (Around 810pC / N) The difference is not big.

[0052] A piezoelectric device according to one embodiment includes the porous piezoelectric ceramic material described above or a porous piezoelectric ceramic material prepared by any of the methods for preparing the porous piezoelectric ceramic material described above.

[0053] The type of the piezoelectric device is not limited, and it can be any piezoelectric device that can use the above-mentioned piezoelectric ceramic material.

[0054] The piezoelectric device of the technical solution of the present invention includes the above-mentioned porous piezoelectric ceramic material. The porous piezoelectric ceramic material is a porous structure, with PZT as the matrix and PNN introduced as the third component. It can achieve low acoustic impedance while maintaining excellent piezoelectric performance, which is conducive to wide application.

[0055] With reference to the above implementation contents, in order to make the technical solution of the present invention more specific, clear and easy to understand, the technical solution of the present invention is now exemplified. However, it should be noted that the contents to be protected by the present invention are not limited to the following embodiments.

[0056] Comparative Example 1

[0057] Comparative Example 1 provides a dense piezoelectric ceramic material and a preparation method thereof. The chemical formula of the dense piezoelectric ceramic material is: 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+x wt%PMMA, x=0. The preparation method is as follows:

[0058] The raw materials are PbO powder, NiO powder, Nb2O5 powder, ZrO2 powder, Bi2O3 powder and TiO2 powder. 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3 The raw materials are weighed according to the stoichiometric ratio of Pb, Ni, Nb, Zr and Ti elements, and the weighed raw materials are placed in a ball mill, zirconium oxide balls and anhydrous ethanol are added to the ball mill, and the ball mill is placed in a planetary ball mill, and the ball mill is milled at a speed of 300r / min for 16h. The mixed powder is obtained after drying. The mass ratio of anhydrous ethanol to the raw material is 2:1, and the mass ratio of zirconium oxide balls used for ball milling to the raw material is 1.5:1. The mixed powder is placed in an alumina crucible for pre-sintering at a pre-sintering temperature of 850℃ and a heating rate of 3℃ / min. After keeping warm for 2 hours, it is naturally cooled to obtain the pre-sintered powder. After grinding the pre-sintered powder, it is ball milled at a speed of 300r / min for 16h, and a slurry is obtained after the second ball milling; the slurry is dried and the dried powder is ground and crushed and passed through an 80-mesh sieve to obtain a ceramic powder.

[0059] The ceramic powder was granulated with polyvinyl alcohol (PVA) having a mass percentage of 8% as a binder, sieved through a 80-mesh sieve, and pressed under a pressure of 4 MPa to form a ceramic green sheet.

[0060] The ceramic green sheets were kept at 610°C for 4 hours for debonding treatment, and then sintered at 1270°C for 3 hours to obtain the piezoelectric ceramic material 0.45Pb(Ni 1 / 3 Nb 2 / 3)O3-0.20PbZrO3-0.35PbTiO3. The upper and lower surfaces of the sintered ceramic sheet were polished to a thickness of 3 mm, and then silver-plated electrodes were provided, and silver was calcined at 620° C. for 20 min to obtain the piezoelectric ceramic sample of Comparative Example 1.

[0061] The base piezoelectric ceramic material 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3 and the piezoelectric ceramic samples of comparative example 1 were tested at room temperature, and the results were shown in Table 1. The acoustic impedance of the dense piezoelectric ceramic material is 32.9 MRrayl, and the d 33 =810pC / N.

[0062] Example 1

[0063] Embodiment 1 provides a porous piezoelectric ceramic material and a preparation method thereof and a porous piezoelectric ceramic material intermediate product. The chemical formula of the porous piezoelectric ceramic material is: 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+xwt%PMMA, x=14. The preparation method is as follows:

[0064] The raw materials are PbO powder, NiO powder, Nb2O5 powder, ZrO2 powder, Bi2O3 powder, TiO2 powder and PMMA powder. 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+14wt%PMMA and the stoichiometric ratio of Pb, Ni, Nb, Zr and Ti elements and PMMA (20μm) were weighed.

[0065] PbO powder, NiO powder, Nb2O5 powder, ZrO2 powder, Bi2O3 powder and TiO2 powder are placed in a ball mill, zirconium oxide balls and anhydrous ethanol are added to the ball mill, the ball mill is placed in a planetary ball mill, and the ball mill is milled at a speed of 300r / min for 16h. The mixed powder is obtained after drying. The mass ratio of anhydrous ethanol to raw materials is 2:1, and the mass ratio of zirconium oxide balls used for ball milling to raw materials is 1.5:1. The mixed powder is placed in an alumina crucible for pre-sintering at a pre-sintering temperature of 850℃ and a heating rate of 3℃ / min. After keeping warm for 2 hours, it is naturally cooled to obtain the pre-sintered powder. After grinding the pre-sintered powder, it is ball milled at a speed of 300r / min for 16h, and a slurry is obtained after the second ball milling; the slurry is dried and the dried powder is ground and crushed and passed through an 80-mesh sieve to obtain ceramic powder.

[0066] The ceramic powder obtained in the previous step was mixed with the PMMA powder and ball-milled again at a ball-milling speed of 150 r / min for 3 h. After drying, a porous piezoelectric ceramic material intermediate product was obtained.

[0067] The porous piezoelectric ceramic material intermediate product is granulated by using polyvinyl alcohol (PVA) with a mass percentage of 8% as a binder, sieved through a sieve with 80 meshes, and pressed into a ceramic green embryo sheet under a pressure of 4 MPa.

[0068] The ceramic green sheets were kept at 600°C for 4 hours for debonding treatment, and then sintered at 1230°C for 2 hours to obtain the piezoelectric ceramic material 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3. The upper and lower surfaces of the sintered ceramic sheet were polished to a thickness of 3 mm, and then silver-plated electrodes were provided thereon, and silver was calcined at 620° C. for 20 minutes to obtain the piezoelectric ceramic sample of Example 1.

[0069] The debonding temperature is 650°C and kept at this temperature for 4 hours; the sintering temperature of the ceramic green sheet after the debonding treatment is 1230°C and kept at this temperature for 2 hours.

[0070] The porous piezoelectric ceramic material 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+14wt%PMMA and the piezoelectric ceramic samples obtained in Example 2 were tested at room temperature, and the results are shown in Table 1. Among them, the acoustic impedance of the porous piezoelectric ceramic material of Example 1 is 21.9MRrayl, and the d 33 =732pC / N.

[0071] Example 2

[0072] Embodiment 2 provides a porous piezoelectric ceramic material and a preparation method thereof and a porous piezoelectric ceramic material intermediate product. The chemical formula of the porous piezoelectric ceramic material is: 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+xwt%PMMA, x=10. The preparation method is similar to that in Example 1, except that the raw materials are PbO powder, NiO powder, Nb2O5 powder, ZrO2 powder, Bi2O3 powder, TiO2 powder and PMMA powder. 1 / 3 Nb 2 / 3)O3-0.20PbZrO3-0.35PbTiO3+10wt% PMMA and the stoichiometric ratio of Pb, Ni, Nb, Zr and Ti elements and PMMA (20μm) were weighed. The sintering temperature of the ceramic green sheet after debonding treatment was 1230℃ and kept warm for 2h.

[0073] The porous piezoelectric ceramic material 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+10wt%PMMA and the piezoelectric ceramic samples obtained in Example 2 were tested at room temperature, and the results are shown in Table 1. Among them, the acoustic impedance of the porous piezoelectric ceramic material of Example 2 is 15.5MRrayl, and the d 33 =554pC / N.

[0074] Example 3

[0075] Embodiment 3 provides a porous piezoelectric ceramic material and a preparation method thereof and a porous piezoelectric ceramic material intermediate product. The chemical formula of the porous piezoelectric ceramic material is: 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+xwt%PMMA, x=3. The preparation method is similar to that in Example 1, except that the raw materials are PbO powder, NiO powder, Nb2O5 powder, ZrO2 powder, Bi2O3 powder, TiO2 powder and PMMA powder. 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+3wt% PMMA and PMMA (5μm) in a stoichiometric ratio of Pb, Ni, Nb, Zr and Ti elements. The raw materials were weighed, and the sintering temperature of the ceramic green sheet after debonding treatment was 1170°C, and the heat preservation was carried out for 2.5h.

[0076] The porous piezoelectric ceramic material 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+3wt%PMMA and the piezoelectric ceramic samples obtained in Example 3 were tested at room temperature, and the results are shown in Table 1. Among them, the acoustic impedance of the porous piezoelectric ceramic material is 27.5MRrayl, and the d 33 =686pC / N. The piezoelectric ceramic material obtained in Example 3 was characterized by cross-section SEM. Figure 2 As shown. Figure 2It can be seen that the piezoelectric ceramic material obtained in Example 3 is a porous structure, the pore size is 1.11 μm to 10.64 μm, and the average pore size is 4.61 μm.

[0077] Example 4

[0078] Embodiment 4 provides a porous piezoelectric ceramic material and a preparation method thereof and a porous piezoelectric ceramic material intermediate product. The chemical formula of the porous piezoelectric ceramic material is: 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+xwt%PMMA, x=5. The preparation method is similar to that in Example 1, except that the raw materials are PbO powder, NiO powder, Nb2O5 powder, ZrO2 powder, Bi2O3 powder, TiO2 powder and PMMA powder. 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+5wt% PMMA and the stoichiometric ratio of Pb, Ni, Nb, Zr and Ti elements and PMMA (5μm) were weighed. The sintering temperature of the ceramic green sheet after debonding treatment was 1170℃ and kept warm for 2.5h.

[0079] The porous piezoelectric ceramic material 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+5wt%PMMA and the piezoelectric ceramic samples obtained in Example 4 were tested at room temperature, and the results are shown in Table 1. Among them, the acoustic impedance of the porous piezoelectric ceramic material is 26.3MRayl, and the d 33 =631pC / N.

[0080] Performance Testing:

[0081] The acoustic impedance of the piezoelectric ceramic materials of Examples 1 to 4 and Comparative Example 1 and the piezoelectric properties of the piezoelectric ceramic samples were tested. The testing method is as follows. The test results are shown in Table 1.

[0082] Acoustic impedance: The calculation formula of acoustic impedance is: Z = ρ × v, ρ is density, v is sound velocity. Density is measured by Archimedes drainage method, and sound velocity is measured by pulse echo method.

[0083] Piezoelectric performance: Before the piezoelectric performance test, the piezoelectric ceramic samples obtained in Examples 1 to 4 and Comparative Example 1 need to be subjected to electric field polarization treatment. The electrode-plated ceramic samples are placed in a withstand voltage tester and a DC electric field of about 30 kV / cm is applied at room temperature for 20 minutes. The polarized ceramic samples are subjected to quasi-static d33 Measuring instrument for testing ceramics 33 .

[0084] Table 1 Piezoelectric ceramic performance test results of Examples 1 to 4 and Comparative Example 1

[0085]

[0086] It can be seen from Table 1 that compared with Comparative Example 1, the acoustic impedance of Examples 1 to 4 of the present invention is smaller, and the piezoelectric coefficient d 33 It can still reach 554-732, indicating that the porous piezoelectric ceramic material of the present invention can achieve low acoustic impedance while maintaining excellent piezoelectric properties. It can also be seen from Table 1 that by comparing Example 3 with Example 4, the mass fraction of PMMA in Example 4 is increased, and the acoustic impedance and d 33 Both decreased.

[0087] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A porous piezoelectric ceramic material, characterized in that: The chemical formula of the porous piezoelectric ceramic material is: 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3.

2. The porous piezoelectric ceramic material according to claim 1, characterized in that: The acoustic impedance of the porous piezoelectric ceramic material is 33 MRayl to 16 MRayl, and the piezoelectric coefficient d 33 The porosity of the porous piezoelectric ceramic material is 6% to 27%.

3. A porous piezoelectric ceramic material intermediate product, characterized in that: The chemical formula of the porous piezoelectric ceramic material intermediate product is: 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3+xwt%PMMA, wherein 0<x≤15.

4. The porous piezoelectric ceramic material intermediate product according to claim 3, characterized in that: The PMMA has a size of 1 μm to 20 μm.

5. A method for preparing a porous piezoelectric ceramic material, characterized in that: The steps include: Based on the chemical formula 0.45Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.20PbZrO3-0.35PbTiO3 stoichiometric ratio, PbO powder, NiO powder, Nb2O5 powder, ZrO2 powder, Bi2O3 powder and TiO2 powder are uniformly mixed, and then pre-sintered to obtain ceramic powder after sufficient reaction; The ceramic powder is mixed evenly with polymethyl methacrylate, wherein the mass fraction of the polymethyl methacrylate is x wt%, wherein 0<x≤15, to obtain a porous piezoelectric ceramic material intermediate product; Granulating the porous piezoelectric ceramic material intermediate product, and then pressing and molding to obtain a ceramic green sheet; and The ceramic green sheet is subjected to debonding and sintering treatment to obtain a porous piezoelectric ceramic material.

6. The method for preparing a porous piezoelectric ceramic material according to claim 5, characterized in that: The temperature of the pre-sintering treatment is 700° C. to 900° C., and the time of the pre-sintering treatment is 1.5 h to 4 h.

7. The method for preparing a porous piezoelectric ceramic material according to claim 5, characterized in that: The size of the ceramic powder is less than 0.2 mm; the size of the polymethyl methacrylate is 1 μm to 20 μm.

8. The method for preparing a porous piezoelectric ceramic material according to claim 5, characterized in that: The granulation operation is: mixing the porous piezoelectric ceramic material intermediate product and the binder evenly, and then passing through an 80-mesh sieve; wherein the mass percentage of the binder is 6% to 10%.

9. The method for preparing a porous piezoelectric ceramic material according to claim 5, characterized in that: The temperature of the debonding is 350°C to 630°C, and the heat preservation time of the debonding is 4h to 6h; The sintering temperature is 1150° C. to 1270° C., and the sintering heat preservation time is 2 h to 4 h.

10. A piezoelectric device, characterized in that: The porous piezoelectric ceramic material comprises the porous piezoelectric ceramic material according to claim 1 or 2 or the porous piezoelectric ceramic material prepared by the preparation method of the porous piezoelectric ceramic material according to any one of claims 5 to 9.

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