High-temperature piezoelectric ceramic materials, their preparation methods and applications

Abstract

The present invention discloses a high-temperature piezoelectric ceramic material, its preparation method and application. The preparation method of the high-temperature piezoelectric ceramic material includes: mixing a Ca source, a Li source, a Mn source, a Bi source, a Ta source and a Ce source to obtain a mixed material, mixing the mixed material evenly, and pre-sintering to obtain a pre-sintered material; mixing the pre-sintered material evenly, granulating, vacuum packaging, and isostatic pressing at a constant temperature to obtain a green body column; subjecting the green body column to debinding treatment and first sintering to obtain a ceramic material; successively coating a high-temperature silver paste, second sintering and high-voltage polarization in silicone oil on the ceramic material to obtain the high-temperature piezoelectric ceramic material. By replacing the Ca element with composite ions and replacing the Ta element with Ce<supgt;4+< / supgt> and controlling the doping amount of Ce<supgt;4+< / supgt>, the ceramic material of the present invention improves the piezoelectric constant, thermal stability and resistivity of the high-temperature piezoelectric ceramic material while ensuring that the Curie temperature does not decrease, and reduces the dielectric loss compared with the calcium bismuth tantalate-based ceramic material.

Description

Technical Field

[0001] The present invention belongs to the technical field of piezoelectric ceramics, and specifically relates to a high-temperature piezoelectric ceramic material, a preparation method thereof, and an application thereof. Background Art

[0002] Bismuth-layered structure piezoelectric ceramics, such as Bi4Ti3O 12 , CaBi4Ti4O 15 and CaBi2Ta2O9, etc., the bismuth-layered structure piezoelectric ceramics are composed of perovskite layers and bismuth-oxygen layers arranged in a specific structure according to a certain rule. The bismuth-layered structure piezoelectric ceramics have the characteristics of high Curie temperature, low aging rate, high dielectric breakdown strength, high mechanical quality factor, etc., and have higher resistivity than some traditional piezoelectric ceramics at high temperature, and the piezoelectric properties are stable. The bismuth-layered structure piezoelectric ceramics are a type of high-temperature piezoelectric material with great development prospects at present, and are also the preferred piezoelectric ceramic materials for high-temperature piezoelectric vibration sensors in the world. The calcium bismuth tantalate (CaBi2Ta2O9)-based ceramic material in the bismuth-layered structure piezoelectric ceramics has a Curie temperature as high as 940 °C, and the piezoelectric constant d 33 is about 5 pC / N, and it is the piezoelectric ceramic material most promising to be applied in high-temperature sensors working at 650 °C. However, in the actual application process, the piezoelectric constant of the calcium bismuth tantalate (CaBi2Ta2O9)-based ceramic material is too low, and its temperature drift of the piezoelectric constant (that is, the change of the piezoelectric constant with temperature) is also relatively large. Therefore, how to improve its piezoelectric constant, resistivity and thermal stability without sacrificing the Curie temperature of the CaBi2Ta2O9-based ceramic material is a key issue. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a preparation method of a high-temperature piezoelectric ceramic material, and the preparation method quantitatively dopes (LiMn) 5+ composite ions (Li and Mn simultaneously replace the A site in the crystal to maintain the electrical neutrality and structural stability of the crystal) at the A site of the calcium bismuth tantalate (CaBi2Ta2O9)-based ceramic material, and dopes Ce 4+ ions at the B site for modification.

[0004] Another purpose of the present invention is to provide the high-temperature piezoelectric ceramic material obtained by the above preparation method.

[0005] The purpose of the present invention is realized by the following technical solutions.

[0006] A preparation method of a high-temperature piezoelectric ceramic material includes the following steps:

[0007] Step 1: Mix the Ca source, Li source, Mn source, Bi source, Ta source and Ce source to obtain a mixed material. Mix the mixed material evenly and pre-sinter it at 850 - 950 °C for 2 - 4 h to obtain a pre-sintered material. Among them, by the number of moles, the ratio of Ca in the Ca source, Li in the Li source, Mn in the Mn source, Bi in the Bi source, Ta in the Ta source and Ce in the Ce source is 0.5:0.5:0.5:2:(2 - 0.4x):x, where 0.03 < x < 0.11;

[0008] In Step 1, the Ca source is CaCO3, the Li source is Li2CO3, the Mn source is MnO2, the Bi source is Bi2O3, the Ta source is Ta2O5, and the Ce source is CeO2.

[0009] In Step 1, the pre-sintering is carried out in an air environment.

[0010] In Step 1, 0.04 ≤ x ≤ 0.1, preferably 0.05 < x ≤ 0.1.

[0011] Step 2: Mix the pre-sintered material evenly, granulate it, vacuum package it, and perform warm isostatic pressing to obtain a green billet column;

[0012] In Step 2, the granulation uses an adhesive. By mass, the ratio of the adhesive to the pre-sintered material is (2 - 5):1.

[0013] In the above technical solution, the adhesive is an aqueous solution of polyvinyl alcohol (PVA). The aqueous solution of polyvinyl alcohol (PVA) is a mixture of polyvinyl alcohol (PVA) and water. By mass, the ratio of water to polyvinyl alcohol in the aqueous solution of polyvinyl alcohol (PVA) is (15 - 20):1.

[0014] In Step 2, the vacuum packaging includes: pressing and packaging the column at a pressure of 2 - 4 MPa.

[0015] In Step 2, the pressure of the warm isostatic pressing is 30 - 50 MPa, the holding time of the warm isostatic pressing is 10 - 20 s, and the temperature of the warm isostatic pressing is 25 - 40 °C.

[0016] In the above technical solution, the pressure increasing rate of the warm isostatic pressing is 2 - 3 MPa / s.

[0017] In Step 1 and Step 2, the mixing evenly is carried out by ball milling. The ball milling uses wet milling, and the medium of the wet milling is anhydrous ethanol.

[0018] In the above technical solution, by mass, the ball-to-material ratio of the ball milling is (3 - 5):1.

[0019] In the above technical solution, drying is carried out after wet grinding. The drying temperature is 70 - 80 °C, and the drying time is 7 - 8 h.

[0020] In the above technical solution, the rotation speed of the ball milling is 300 - 400 r / min, and the ball milling time is 8 - 12 h.

[0021] Step 3: Subject the green body column to debinding treatment, and perform the first sintering at 1000 - 1300 °C to obtain a ceramic material. Among them, the first sintering time is 3 - 7 h;

[0022] In step 3, the debinding treatment temperature is 550 - 650 °C, and the debinding treatment time is 0.5 - 2 h.

[0023] In step 3, the first sintering is carried out in an air environment.

[0024] In the above technical solution, the heating rate to the 550 - 650 °C is 3 - 5 °C / min.

[0025] In step 3, the heating rate to the 1000 - 1300 °C is 3 - 5 °C / min.

[0026] Step 4: Coat the ceramic material with high-temperature silver paste (electrode), perform the second sintering (electrode sintering), and high-voltage polarization in silicone oil to obtain a high-temperature piezoelectric ceramic material.

[0027] In step 4, the second sintering includes: keeping the temperature at 800 - 850 °C for 10 - 40 min in an air environment.

[0028] In step 4, the high-voltage polarization in silicone oil includes: polarizing in silicone oil at 150 - 200 °C with a polarization field strength of 10 - 12 kV / mm for 30 - 40 min.

[0029] The high-temperature piezoelectric ceramic material obtained by the above preparation method.

[0030] The application of the above high-temperature piezoelectric ceramic material in an acceleration sensor.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. The high-temperature piezoelectric ceramic material of the present invention replaces the Ca element with a composite ion (LiMn) 5+ and replaces the Ta element with Ce 4+ and controls Ce 4+The doping amount of [subject matter not specified] compared to the calcium bismuth tantalate (CaBi2Ta2O9) - based ceramic material. In the present invention, while ensuring that the Curie temperature does not decrease, the piezoelectric constant, thermal stability, and resistivity of the high - temperature piezoelectric ceramic material are improved, and the dielectric loss is reduced. The Curie temperature of the high - temperature piezoelectric ceramic material of the present invention can reach up to 945 °C at most. At room temperature, the piezoelectric constant is as high as 15 pC / N, and at 650 °C, the piezoelectric constant can still reach 13 pC / N, and the dielectric loss can be as low as 0.16%.

[0033] 2. When the high - temperature piezoelectric ceramic material of the present invention is at room temperature to 650 °C, the temperature drift of the piezoelectric constant is very small, within 14%, that is, the high - temperature piezoelectric ceramic material of the present invention can operate stably at 650 °C for a long time. When the high - temperature piezoelectric ceramic material of the present invention is at room temperature to 800 °C, the change of the dielectric loss with temperature is small.

[0034] 3. The resistivity of the high - temperature piezoelectric ceramic material of the present invention at 650 °C can reach 10 6 Ω·cm. Compared with the calcium bismuth tantalate (CaBi2Ta2O9) - based ceramic material, it is increased by two orders of magnitude at the same temperature, and has great application prospects in the field of high - temperature devices.

[0035] 4. The preparation method of the present invention is simple and the cost is low, which is suitable for large - scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 FIG. is the XRD diffraction pattern of the high - temperature piezoelectric ceramic materials prepared in Examples 1 - 6. Among them, the inset is a partially enlarged view;

[0037] Figure 2 FIG. is the graph of the change of dielectric loss with temperature of the high - temperature piezoelectric ceramic materials prepared in Examples 1 - 6;

[0038] Figure 3 FIG. is the Curie temperature graph of the high - temperature piezoelectric ceramic material prepared in Example 4;

[0039] Figure 4 FIG. is the graph of the change of piezoelectric constant with temperature of the high - temperature piezoelectric ceramic material prepared in Example 4;

[0040] Figure 5 FIG. is the resistivity of the high - temperature piezoelectric ceramic materials prepared in Examples 1 - 6 at 650 °C. DETAILED DESCRIPTION OF THE INVENTION

[0041] The technical solution of the present invention will be further described below with specific examples.

[0042] In the following examples and comparative examples, the Ca source is CaCO3, the Li source is Li2CO3, the Mn source is MnO2, the Bi source is Bi2O3, the Ta source is Ta2O5, the Ce source is CeO2, and the Na source is Na2CO3. CaCO3, Li2CO3, MnO2, Bi2O3, Ta2O5, CeO2 and Na2CO3 are all of analytical purity.

[0043] High-temperature silver paste: Xi'an Hongxingxing Electronic Paste Technology Co., Ltd., model C-1002.

[0044] Unless otherwise specified, the following piezoelectric constants, dielectric constants and dielectric losses are all measured at room temperature of 20-25 °C.

[0045] The calculation method of the temperature drift of the piezoelectric constant is: ((piezoelectric constant at 650 °C - piezoelectric constant at room temperature) / piezoelectric constant at room temperature) * 100%.

[0046] Examples 1-6

[0047] A preparation method of a high-temperature piezoelectric ceramic material, comprising the following steps:

[0048] Step 1, mix the Ca source, Li source, Mn source, Bi source, Ta source and Ce source to obtain a mixture, ball-mill the mixture until it is evenly mixed (wet milling is used for ball milling, and the medium for wet milling is anhydrous ethanol. By mass, the ratio of anhydrous ethanol to the mixture used in this step for ball milling is 0.8:1, the rotation speed of ball milling is 300 r / min, the time of ball milling is 8 h, and by mass, the ball-to-material ratio of ball milling is 4:1), dry at 75 °C for 8 h, and pre-sinter at 850 °C for 3 h in an air environment to obtain a pre-sintered material, wherein, by mole fraction, the ratio of Ca in the Ca source, Li in the Li source, Mn in the Mn source, Bi in the Bi source, Ta in the Ta source and Ce in the Ce source is A. The value of A is shown in Table 1;

[0049] Table 1

[0050]

[0051] Step 2: Ball-mill the pre-sintered material until it is uniformly mixed (wet ball-milling is used, and the medium for wet ball-milling is absolute ethanol. By mass, the ratio of absolute ethanol to the pre-sintered material used in this step of ball-milling is 0.8:1, the rotation speed of ball-milling is 300 r / min, the time of ball-milling is 8 h, and by mass, the ball-to-material ratio of ball-milling is 4:1). Dry at 75 °C for 8 h, granulate, use a dry pressing tablet press to press and encapsulate at a pressure of 3 MPa (vacuum encapsulation), and perform warm isostatic pressing at a pressure of 40 MPa for 10 s (the pressure increase rate of warm isostatic pressing is 3 MPa / s, and the temperature of warm isostatic pressing is 40 °C) to obtain a green body column with a thickness of 13 mm and a diameter of 10 mm. Among them, a binder is used for granulation. By mass, the ratio of the binder to the pre-sintered material is 4:1, the binder is an aqueous solution of polyvinyl alcohol (PVA), and the aqueous solution of polyvinyl alcohol (PVA) is a mixture of polyvinyl alcohol (PVA) and water. By mass, the ratio of water to polyvinyl alcohol (PVA) in the aqueous solution of polyvinyl alcohol (PVA) is 18:1;

[0052] Step 3: Debind the green body column at 650 °C for 2 h (the heating rate to 650 °C is 4 °C / min) (discharge the binder, and at the same time, the ceramic material can have a certain hardness), and then sinter at 1180 °C (the first sintering) for 6 h in an air environment (the heating rate to 1180 °C is 4 °C / min) to obtain the ceramic material;

[0053] Step 4: Cut the ceramic material into ceramic slices with a thickness of 0.6 mm, polish both sides of the ceramic slices with 600-mesh sandpaper. After polishing, coat both sides of the ceramic slices with high-temperature silver paste (electrode coating). In an air environment, keep it at 850 °C for 20 min for the second sintering (electrode sintering). After the second sintering, polish on A4 paper to remove the surface silver oxide to obtain the precursor of the high-temperature piezoelectric ceramic material. Subject the precursor of the high-temperature piezoelectric ceramic material to high-voltage polarization in silicone oil to obtain the high-temperature piezoelectric ceramic material. Among them, the high-voltage polarization in silicone oil includes: polarize in silicone oil at 180 °C with a polarization field strength of 11 kV / mm for 40 min (polarization field strength = polarization voltage (DC voltage) / thickness of the precursor of the high-temperature piezoelectric ceramic material).

[0054] Piezoelectric constant of the high-temperature piezoelectric ceramic material prepared in Example 1 d 33 = 8 pC / N, dielectric constant ε = 68, dielectric loss tanδ = 0.18%, resistivity ρ at 650 °C = 1.8×10 6 Ω●㎝.

[0055] Piezoelectric constant of the high-temperature piezoelectric ceramic material prepared in Example 2 d 33= 10 pC / N, dielectric constant ε = 69, dielectric loss tanδ = 0.20%, resistivity ρ at 650 °C = 3.4×10 6 Ω·cm.

[0056] The piezoelectric constant of the high-temperature piezoelectric ceramic material prepared in Example 3 d 33 = 13 pC / N, dielectric constant ε = 71, dielectric loss tanδ = 0.25%, resistivity ρ at 650 °C = 5.6×10 6 Ω·cm.

[0057] The piezoelectric constant of the high-temperature piezoelectric ceramic material prepared in Example 4 d 33 = 15 pC / N, dielectric constant ε = 69, dielectric loss tanδ = 0.16%, resistivity ρ at 650 °C = 7.1×10 6 Ω·cm.

[0058] The piezoelectric constant of the high-temperature piezoelectric ceramic material prepared in Example 5 d 33 = 14 pC / N, dielectric constant ε = 70, dielectric loss tanδ = 0.21%, resistivity ρ at 650 °C = 5.8×10 6 Ω·cm.

[0059] The piezoelectric constant of the high-temperature piezoelectric ceramic material prepared in Example 6 d 33 = 11 pC / N, dielectric constant ε = 68, dielectric loss tanδ = 0.25%, resistivity ρ at 650 °C = 2.8×10 6 Ω·cm.

[0060] The XRD diffraction patterns of the high-temperature piezoelectric ceramic materials prepared in Examples 1 - 6 are as Figure 1 shown. It can be seen from Figure 1 that the high-temperature piezoelectric ceramic materials prepared in Examples 1 - 6 all have a typical Aurivillius phase structure, and all diffraction peaks can be indexed according to the PDF card 72 - 2365. Figure 1 It can be seen from 4+ that there is no generation of a second phase in the high-temperature piezoelectric ceramic materials prepared in Examples 1 - 6, indicating that Ce Figure 1 has completely entered CaBi2Ta2O9. The diffraction peak with the highest intensity corresponds to the (115) crystal plane, indicating that the high-temperature piezoelectric ceramic material is a typical bismuth layer phase structure. It can be seen from the θ inset of θThe angular direction deviation indicates that the doping amounts of different Ce sources will cause lattice distortion of the high-temperature piezoelectric ceramic material.

[0061] The variation of the dielectric loss of the high-temperature piezoelectric ceramic materials prepared in Examples 1 to 6 with temperature is as Figure 2 shown ( Figure 2 in the figure, the ordinate "Loss" represents the dielectric loss, and the temperature variation range on the abscissa is: room temperature to 1000 °C). It can be seen from Figure 2 that in the temperature range of room temperature to 800 °C, the dielectric loss of the high-temperature piezoelectric ceramic materials prepared in Examples 1 to 6 increases slowly with the increase of temperature, indicating that the high-temperature piezoelectric ceramic materials prepared in Examples 1 to 6 have excellent stability at high temperatures.

[0062] The variation of the piezoelectric constant of the high-temperature piezoelectric ceramic material prepared in Example 4 with temperature is as Figure 4 shown (the temperature variation range is: room temperature to 650 °C. The high-temperature piezoelectric ceramic material prepared in Example 4 is placed in a high-temperature test furnace for testing the variation of the piezoelectric constant with temperature). It can be known from Figure 4 that the piezoelectric constant of the high-temperature piezoelectric ceramic material prepared in Example 4 at room temperature is 15 pC / N, and the piezoelectric constant can still reach 13 pC / N at 650 °C, and the temperature drift of the piezoelectric constant is 13%.

[0063] The resistivity of the high-temperature piezoelectric ceramic materials prepared in Examples 1 to 6 at 650 °C is as Figure 5 shown. It can be known from Figure 5 that at 650 °C, the resistivity of the high-temperature piezoelectric ceramic materials prepared in Examples 1 to 6 all reaches 10 6 Ω·cm, and the resistivity ρ of the high-temperature piezoelectric ceramic material prepared in Example 4 is as high as 7.1×10 6 Ω·cm, with the best resistivity.

[0064] The Curie temperature of the high-temperature piezoelectric ceramic material prepared in Example 4 is as Figure 3 shown. The dielectric constant of the high-temperature piezoelectric ceramic material prepared in Example 4 gradually increases with the increase of temperature, reaches a peak at 942 °C, and then drops sharply. Its mutation temperature point is 942 °C, and 942 °C is the Curie temperature point of the high-temperature piezoelectric ceramic material prepared in Example 4.

[0065] The Curie temperatures of the high-temperature piezoelectric ceramic materials prepared in Examples 1 to 6 ( T c ) are shown in Table 2.

[0066] Table 2

[0067]

[0068] Comparative Examples 1 to 6

[0069] A method for preparing a piezoelectric ceramic material is basically the same as that of Example 1, and the only difference is that: the mixture is different. The mixtures of Comparative Examples 1 to 6 are all obtained by mixing a Ca source, a Li source, a Mn source, a Bi source, and a Ta source. In terms of the number of moles, the ratio of Ca in the Ca source, Li in the Li source, Mn in the Mn source, Bi in the Bi source, and Ta in the Ta source is B. The value of B is shown in Table 3.

[0070] Table 3

[0071]

[0072] The piezoelectric constant of the piezoelectric ceramic material prepared in Comparative Example 1 d 33 = 7.0 pC / N, the dielectric constant ε = 68, the dielectric loss tanδ = 0.20%, the Curie temperature T c = 945 °C, the resistivity ρ at 650 °C = 7.2×10 5 Ω●cm.

[0073] The piezoelectric constant of the piezoelectric ceramic material obtained in Comparative Example 2 d 33 = 8.5 pC / N, the dielectric constant ε = 69, the dielectric loss tanδ = 0.24%, the Curie temperature T c = 945 °C, the resistivity ρ at 650 °C = 8.9×10 5 Ω●cm.

[0074] The piezoelectric constant of the piezoelectric ceramic material obtained in Comparative Example 3 d 33 = 9.0 C / N, the dielectric constant ε = 70, the dielectric loss tanδ = 0.27%, the Curie temperature T c = 945 °C, the resistivity ρ at 650 °C = 1.2×10 6 Ω●cm.

[0075] The piezoelectric constant of the piezoelectric ceramic material obtained in Comparative Example 4 d 33 = 12 pC / N, the dielectric constant ε = 68, the dielectric loss tanδ = 0.21%, the Curie temperature T c = 940 °C, the resistivity ρ at 650 °C = 3.2×10 6 Ω●cm.

[0076] The piezoelectric constant of the piezoelectric ceramic material obtained in Comparative Example 5 d 33= 11 pC / N, the dielectric constant ε = 70, the dielectric loss tanδ = 0.27%, the Curie temperature T c = 940 °C, the resistivity ρ at 650 °C = 1.8×10 6 Ω●cm.

[0077] The piezoelectric constant of the piezoelectric ceramic material obtained in Comparative Example 6 d 33 = 10.5 pC / N, the dielectric constant ε = 71, the dielectric loss tanδ = 0.22%, the Curie temperature T c = 940 °C, the resistivity ρ at 650 °C = 9.5×10 5 Ω●cm.

[0078] Comparative Examples 7 - 12

[0079] A method for preparing a piezoelectric ceramic material is basically the same as that in Example 1, except that: the mixed materials are different. The mixed materials in Comparative Examples 7 - 12 are all obtained by mixing a Ca source, a Na source, a Bi source, a Li source, a Ce source and a Ta source. By mole fraction, the ratio of Ca in the Ca source, Na in the Na source, Bi in the Bi source, Li in the Li source, Ce in the Ce source and Ta in the Ta source is C. The value of C is shown in Table 4.

[0080] Table 4

[0081]

[0082] The chemical formula of the piezoelectric ceramic material in Comparative Examples 7 - 12 is Ca 0.5 (Na 0.5 Bi 0.5 ) 0.5-y (Li 0.5 Ce 0.5 ) y Bi2Ta2O9. In Comparative Examples 7 - 12, y The values are 0.01, 0.03, 0.05, 0.07, 0.09, 0.11 in sequence. The piezoelectric ceramic material prepared in Comparative Examples 7 - 12 is (Li 0.5 Ce 0.5 ) 2.5+ substituting (Na 0.5 Bi 0.5 ) 2+ , which is different from the composite ion (LiMn) 5+ substituting the Ca element and Ce 4+ substituting the Ta element in the examples of the present invention.

[0083] The piezoelectric constant of the piezoelectric ceramic material prepared in Comparative Example 7 d33 = 8.2 pC / N, dielectric constant ε = 70, dielectric loss tanδ = 0.22%, Curie temperature T c = 945 °C, resistivity ρ at 650 °C = 8.8×10 5 Ω●cm.

[0084] Piezoelectric constant of the piezoelectric ceramic material prepared in Comparative Example 8 d 33 = 9.0 pC / N, dielectric constant ε = 70, dielectric loss tanδ = 0.22%, Curie temperature T c = 945 °C, resistivity ρ at 650 °C = 1.3×10 6 Ω●cm.

[0085] Piezoelectric constant of the piezoelectric ceramic material prepared in Comparative Example 9 d 33 = 11.5 pC / N, dielectric constant ε = 71, dielectric loss tanδ = 0.27%, Curie temperature T c = 945 °C, resistivity ρ at 650 °C = 2.8×10 6 Ω●cm.

[0086] Piezoelectric constant of the piezoelectric ceramic material prepared in Comparative Example 10 d 33 = 12.5 pC / N, dielectric constant ε = 72, dielectric loss tanδ = 0.19%, Curie temperature T c = 940 °C, resistivity ρ at 650 °C = 4.2×10 6 Ω●cm.

[0087] Piezoelectric constant of the piezoelectric ceramic material prepared in Comparative Example 11 d 33 = 12 pC / N, dielectric constant ε = 72, dielectric loss tanδ = 0.21%, Curie temperature T c = 940 °C, resistivity ρ at 650 °C = 3.0×10 6 Ω●cm.

[0088] Piezoelectric constant of the piezoelectric ceramic material prepared in Comparative Example 12 d 33 = 11 pC / N, dielectric constant ε = 73, dielectric loss tanδ = 0.24%, Curie temperature T c = 940 °C, resistivity ρ at 650 °C = 1.1×10 6 Ω●cm.

[0089] The above provides an exemplary description of the present invention. It should be noted that any simple deformation, modification, or equivalent replacement that can be made by those skilled in the art without creative efforts falls within the protection scope of the present invention without departing from the core of the present invention.

Claims

1. A preparation method of a high-temperature piezoelectric ceramic material, characterized in that, It includes the following steps: Step 1: Mix a Ca source, a Li source, a Mn source, a Bi source, a Ta source and a Ce source to obtain a mixed material. Mix the mixed material evenly and pre-sinter it at 850 - 950 °C for 2 - 4 h to obtain a pre-sintered material. Among them, in terms of the number of moles, the ratio of Ca in the Ca source, Li in the Li source, Mn in the Mn source, Bi in the Bi source, Ta in the Ta source and Ce in the Ce source is 0.5:0.5:0.5:2:(2 - 0.4x):x, where x = 0.07; Step 2: Mix the pre-sintered material evenly, granulate it, vacuum package it, and perform warm isostatic pressing to obtain a green billet column. The pressure of the warm isostatic pressing is 30 - 50 MPa, and the temperature of the warm isostatic pressing is 25 - 40 °C; Step 3: Subject the green billet column to debinding treatment and perform the first sintering at 1000 - 1300 °C to obtain a ceramic material. Among them, the time of the first sintering is 3 - 7 h; Step 4: Successively coat the ceramic material with high-temperature silver paste, perform the second sintering and high-voltage polarization in silicone oil to obtain a high-temperature piezoelectric ceramic material; The preparation method quantitatively dopes (LiMn) 5+ composite ions at the A site in the calcium bismuth tantalate-based ceramic material, and dopes Ce 4+ ions at the B site.

2. The preparation method according to claim 1, characterized in that, In Step 2, an adhesive is used for granulation. In terms of mass parts, the ratio of the adhesive to the pre-sintered material is (2 - 5):

1.

3. The preparation method according to claim 2, wherein The adhesive is an aqueous solution of polyvinyl alcohol. The aqueous solution of polyvinyl alcohol is a mixture of polyvinyl alcohol and water. In terms of mass parts, the ratio of water to polyvinyl alcohol in the aqueous solution of polyvinyl alcohol is (15 - 20):

1.

4. The preparation method according to claim 1, characterized in that, In Step 2, the vacuum packaging includes: pressing and packaging the column at a pressure of 2 - 4 MPa.

5. The preparation method according to claim 1, characterized in that, In Step 2, the holding time of the warm isostatic pressing is 10 - 20 s.

6. The preparation method according to claim 1, characterized in that, In Step 3, the temperature of the debinding treatment is 550 - 650 °C, and the time of the debinding treatment is 0.5 - 2 h.

7. The preparation method according to claim 1, characterized in that, In Step 4, the second sintering includes: keeping the temperature at 800 - 850 °C for 10 - 40 min in an air environment.

8. The preparation method according to claim 1, wherein In Step 4, the high-voltage polarization in silicone oil includes: polarizing in silicone oil at 150 - 200 °C with a polarization field strength of 10 - 12 kV / mm for 30 - 40 min.

9. A high-temperature piezoelectric ceramic material obtained by the preparation method according to any one of claims 1 - 8.

10. Application of the high-temperature piezoelectric ceramic material according to claim 9 in an acceleration sensor.

Images