Bismuth-reduced ternary ceramic material of sodium bismuth titanate-strontium titanate-lead titanate with high strain performance and preparation method thereof

Abstract

The application discloses a ternary ceramic material of sodium bismuth titanate- strontium titanate-lead titanate with high strain performance obtained by bismuth reduction and a preparation method thereof. The application aims at solving the problems of unstable performance of sodium bismuth titanate ceramic modified by defects, and the need of large electric field driving. The chemical general formula of the ternary ceramic material of sodium bismuth titanate- strontium titanate-lead titanate is (Na 0.5 Bi 0.5 ) 0.75(1‑x) Sr 0.25(1‑x) Pb x TiO3. The ternary ceramic material of sodium bismuth titanate- strontium titanate-lead titanate is prepared by mixing Na2CO3, SrCO3, TiO2, Bi2O3 and PbO in a stoichiometric ratio of (Na 0.5 Bi 0.5 ) 0.75(1‑x) Sr 0.25(1‑x) Pb x TiO3, and then by pressing and sintering. The maximum strain of the ternary ceramic material of sodium bismuth titanate- strontium titanate-lead titanate under an electric field of 80 kV / cm is 2.77%, and the strain memory effect is 1.75%.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of piezoelectric ceramics, and particularly relates to a bismuth sodium titanate-strontium titanate-lead titanate ceramic material with high strain performance obtained by reduction of bismuth elements and a preparation method thereof, which is applied as a driving material with large electrostrictive strain and large strain memory effect. BACKGROUND

[0002] Piezoelectric ceramics are a kind of electronic ceramics with good electromechanical conversion performance, and are widely applied in the fields of sensors and driving. Piezoelectric ceramics can be deformed under the action of an external electric field, and the deformation generally does not have a memory effect, and disappears when the external electric field is removed. However, in some scenarios, piezoelectric actuators need to remain a certain deformation (electro-shape memory effect, SME) under the removal of an electric field or a low electric field, such as ferroelectric random storage technology and mechanical relays. Therefore, it is of great significance to develop piezoelectric ceramics with good electro-shape memory effect.

[0003] Currently discovered electro-memory effect ceramics are mainly realized by designing anti-ferroelectric-ferroelectric phase transition and defect modification. Doped modified lead zirconate titanate ceramics, lead zirconate titanate single crystals; sodium bismuth titanate ceramics, bismuth ferrite ceramics and textured bismuth tungstate ceramics modified by defects, etc. These ceramic materials generally need a large electric field to drive, and the high electrostrictive strain performance induced by defects is not stable. Therefore, it is an important technical problem to be solved at present to design a piezoelectric ceramic with low field operation, stable large electromechanical response and memory effect. SUMMARY

[0004] The application aims to solve the problems of unstable performance of sodium bismuth titanate ceramics modified by defects and the need for large electric field driving, and provides a ternary sodium bismuth titanate-strontium titanate-lead titanate ceramic material with high strain performance obtained by reduction of bismuth and a preparation method thereof.

[0005] The chemical composition general formula of the ternary sodium bismuth titanate-strontium titanate-lead titanate ceramic material with high strain performance obtained by reduction of bismuth is (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3, wherein x=0.05-0.4; the ternary sodium bismuth titanate-strontium titanate-lead titanate ceramic material is prepared by mixing Na2CO3, SrCO3, TiO2, Bi2O3 and PbO in a stoichiometric ratio of (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3, and then being pressed and sintered.

[0006] The application utilizes bismuth reduction to obtain a preparation method of a high-strain-performance ternary ceramic material of sodium bismuth titanate- strontium titanate-lead titanate, which is implemented according to the following steps:

[0007] I. batching:

[0008] According to the stoichiometric ratio (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3, Na2CO3, SrCO3, TiO2, Bi2O3 and PbO are weighed as raw materials;

[0009] II. ball milling:

[0010] The raw materials in step I are put into a ball mill tank for ball milling treatment, and mixed powder is obtained after drying;

[0011] III. pre-sintering:

[0012] The mixed powder is subjected to pre-sintering treatment at a temperature of 850-950 ℃, and the pre-sintered powder is obtained;

[0013] IV. secondary ball milling:

[0014] The pre-sintered powder is again put into a ball mill tank for secondary ball milling treatment, and the ball-mixed powder is obtained after drying;

[0015] V. granulation:

[0016] The ball-mixed powder is ground and sieved, and then a binder is added for sufficient grinding and granulation, and the granulated powder is obtained;

[0017] VI. forming:

[0018] The granulated powder is put into a mold and pressed into a sheet-shaped material;

[0019] VII. degassing:

[0020] The sheet-shaped material is subjected to heat treatment for degassing at a temperature of 500-600 ℃ using a sintering furnace, and the degassed ceramic sheet is obtained;

[0021] VIII. sintering:

[0022] The degassed ceramic sheet is subjected to sintering treatment at a temperature of 1130-1150 ℃, and the ternary ceramic material is obtained;

[0023] IX. electrode plating:

[0024] Both sides of the ternary ceramic material are polished, and then conductive silver paste is uniformly applied to both sides of the ceramic, and after drying, annealing treatment is performed at 500-600 ℃, and the ceramic sheet with silver electrodes is obtained;

[0025] X. Electric field pre-treatment

[0026] The ceramic sheet with silver electrode is polarized in the electric field of 40-70 kV / cm to make part of bismuth elements in the ceramic to have reduction reaction, so that the ternary ceramic material of sodium bismuth titanate-strontium titanate-lead titanate with high strain performance is obtained.

[0027] The application provides a ternary ceramic of sodium bismuth titanate-strontium titanate-lead titanate, which utilizes the strong reduction reaction of bismuth elements in the ceramic on one side under the electric field and the weak reduction reaction on the other side, so that larger electrostrictive strain and electrostrictive strain memory effect are obtained. The application of the ternary ceramic material of sodium bismuth titanate-strontium titanate-lead titanate with high strain performance obtained by reduction of bismuth is to use the ternary ceramic material of sodium bismuth titanate-strontium titanate-lead titanate as a driving material.

[0028] The ternary ceramic of sodium bismuth titanate-strontium titanate-lead titanate (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3 (x=0.4) has a maximum strain of 2.77% under the electric field of 80 kV / cm, and a strain memory effect of 1.75%. The ternary system has simple preparation process, low material cost, larger electrostrictive strain and memory effect, and has important significance in the field of piezoelectric driving. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 XRD patterns of the ceramic of Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3 (x=0.05, 0.1, 0.2, 0.4) under the conditions of the embodiment are given;

[0030] Figure 2 Strain curve diagrams of the ceramic of Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3 (x=0.05, 0.1, 0.2, 0.4) under the conditions of the embodiment are given;

[0031] Figure 3 Strain curve diagrams of the ceramic of Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb xThe maximum strain and strain memory effect test graph of TiO3(x=0.05, 0.1, 0.2, 0.4) ceramic at different frequencies. DETAILED DESCRIPTION

[0032] Specific embodiment one: the chemical composition general formula of the ternary ceramic material of sodium bismuth titanate- strontium titanate-lead titanate with high strain performance obtained by bismuth reduction is (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3, wherein x=0.05-0.4; the ternary ceramic material of sodium bismuth titanate- strontium titanate-lead titanate is mixed by Na2CO3, SrCO3, TiO2, Bi2O3 and PbO in stoichiometric ratio (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3, and then sintered by pressing.

[0033] Specific embodiment two: the difference between this embodiment and specific embodiment one is that x in the chemical composition general formula (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3 is 0.2-0.4.

[0034] In the chemical formula of the ternary ceramic material of this embodiment, x is preferably 0.2-0.4.

[0035] Specific embodiment three: the preparation method of the sodium bismuth titanate-based ceramic with high strain performance obtained by asymmetric polarization-induced ceramic bending deformation is implemented according to the following steps:

[0036] I. batching:

[0037] Na2CO3, SrCO3, TiO2, Bi2O3 and PbO are weighed as raw materials in stoichiometric ratio (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3;

[0038] II. ball milling:

[0039] The raw materials of step I are put into a ball mill tank for ball milling treatment, and mixed powder is obtained after drying;

[0040] III. pre-sintering:

[0041] The mixed powder is pre-sintered at a temperature of 850-950°C to obtain a pre-sintered powder;

[0042] Four, secondary ball milling:

[0043] The pre-sintered powder is again put into a ball mill tank for secondary ball milling treatment, and the ball-mixed powder is obtained after drying;

[0044] Five, granulation:

[0045] The ball-mixed powder is ground, sieved, and then granulated by adding a binder and grinding thoroughly to obtain a granulated powder;

[0046] Six, molding:

[0047] The granulated powder is put into a mold to be pressed into a sheet;

[0048] Seven, degassing:

[0049] The sheet is heat treated at a temperature of 500-600°C in a sintering furnace to obtain a degassed ceramic sheet;

[0050] Eight, sintering:

[0051] The degassed ceramic sheet is sintered at a temperature of 1130-1150°C to obtain a ternary ceramic material;

[0052] Nine, electrode plating:

[0053] Both sides of the ternary ceramic material are polished, and then conductive silver paste is uniformly applied to both sides of the ceramic, which is then annealed at 500-600°C to obtain a ceramic sheet with silver electrodes;

[0054] Ten, electric field pretreatment:

[0055] The ceramic sheet with silver electrodes is polarized in an electric field of 40-70 kV / cm to cause a reduction reaction of part of the bismuth elements in the ceramic, thereby obtaining a sodium bismuth titanate-strontium titanate-lead titanate ternary ceramic material with high strain performance.

[0056] The present embodiment utilizes the reduction reaction of bismuth elements to stabilize the polarization effect and obtain a larger electrostrictive strain and electrostrictive strain memory effect at a lower electric field.

[0057] Specific embodiment four: The difference between the present embodiment and the third embodiment is that the ball milling in step two is carried out at a speed of 200 r / min for 10-12 h.

[0058] Specific embodiment five: The difference between the present embodiment and the third or fourth embodiment is that the pre-sintering time in step three is 2-6 h.

[0059] Specific implementation six: the difference between this implementation and one of specific implementations three to five is that the binder described in step five is 5wt.% polyvinyl alcohol (PVA).

[0060] Specific implementation seven: the difference between this implementation and one of specific implementations three to six is that the heat treatment degassing time in step seven is 1-2h.

[0061] Specific implementation eight: the difference between this implementation and one of specific implementations three to seven is that the sintering treatment time in step eight is 3-3.5h.

[0062] Specific implementation nine: the difference between this implementation and one of specific implementations three to eight is that the annealing treatment time in step nine is 0.4-0.8h.

[0063] Specific implementation ten: the difference between this implementation and one of specific implementations three to nine is that step ten places the ceramic sheet with silver electrodes in an electric field of 40-70kV / cm for polarization treatment for 50-70s.

[0064] Example: the preparation method of the high-strain-performance ternary ceramic material of sodium bismuth titanate-strontium titanate-lead titanate obtained by bismuth reduction is implemented according to the following steps:

[0065] I. batching:

[0066] According to the stoichiometric ratio (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3, Na2CO3, SrCO3, TiO2, Bi2O3 and PbO are weighed as raw materials;

[0067] II. Ball milling:

[0068] The raw materials of step I are placed in a ball mill tank for ball milling treatment, the ball milling medium is anhydrous ethanol and zirconia grinding balls, the ball milling conditions are: the ball-to-material mass ratio is 5:1, the rotation speed is 200r / min, the ball milling time is 12h, and the slurry is dried at 80℃ to obtain mixed powder;

[0069] III. Pre-sintering:

[0070] The mixed powder is pre-sintered at a temperature rising rate of 10℃ / min to 900℃ and kept for 4h, to obtain pre-sintered powder;

[0071] IV. Second ball milling:

[0072] The pre-sintered powder is again put into a ball mill tank, the ball mill medium is anhydrous ethanol and zirconium oxide grinding balls, the ball milling conditions are: rotation speed is 200 r / min, ball milling time is 12 h, and the ball-mixed powder is obtained after drying (80°C) after secondary ball milling treatment;

[0073] V. Granulation:

[0074] The ball-mixed powder is ground, sieved, and then 5 wt.% polyvinyl alcohol (PVA) binder is added and ground to obtain a granulated powder;

[0075] VI. Forming:

[0076] The granulated powder is put into a mold and pressed into a sheet-shaped material with a diameter of 10 mm and a thickness of 0.5 mm under a pressure of 8 MPa;

[0077] VII. Glue removal:

[0078] The sheet-shaped material is heat treated to remove glue by using a sintering furnace with a heating rate of 2°C / min to 600°C and holding for 1 h, and a ceramic sheet after glue removal is obtained;

[0079] VIII. Sintering:

[0080] The ceramic sheet after glue removal is sintered by heating at a rate of 10°C / min to 1150°C and holding for 3 h, and a ternary ceramic material is obtained;

[0081] IX. Electrode plating:

[0082] Both sides of the ternary ceramic material are polished, and then conductive silver paste is uniformly applied to both sides, and after drying, annealing treatment is performed at 500°C for 30 min, and a ceramic sheet with silver electrodes is obtained;

[0083] X. Electric field pretreatment

[0084] The ceramic sheet with silver electrodes is polarized in an electric field of 60 kV / cm for 60 s, so that part of the bismuth elements in the ceramic undergo a reduction reaction, and a sodium bismuth titanate- strontium titanate-lead titanate ternary ceramic material with high strain performance is obtained.

[0085] The (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3(x = 0.05, 0.1, 0.2, 0.4) ternary ceramic material prepared in this example has a maximum electrostrictive strain of 2.77% and an electrostrictive shape memory effect of 1.77% at 80 kV / cm and 0.1 Hz.

[0086] Figure 1The XRD patterns of (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3(x = 0.05, 0.1, 0.2, 0.4) ceramics are shown in the following table. Figure 1 It can be seen that the prepared ceramic samples are pure perovskite phase, and no impurity phase is produced. In addition, the diffraction peak of (200) crystal plane appears splitting, and when x = 0.05, 0.1, the peak intensity ratio is not 1:2, which shows that the phase structure of the ceramic is R, T two-phase coexistence; when x = 0.2, 0.4, the peak intensity ratio is 1:2, which proves to be T phase.

[0087] Figure 2 The strain curves of (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3(x = 0.05, 0.1, 0.2, 0.4) ceramics under the same frequency (10Hz) 60kV / cm are shown in the following table. Figure 2 It can be seen that the maximum strain of (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3(x = 0.05, 0.1, 0.2, 0.4) ceramics under 60kV / cm is 0.76%, and the strain memory effect is 0.67%(x = 0.2).

[0088] Figure 3 The maximum strain and strain memory effect of (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3(x = 0.05, 0.1, 0.2, 0.4) ceramics at different frequencies are shown in the following table, wherein x = 0.05, 0.1, 0.2 is applied to 50kV / cm, and x = 0.4 is applied to 80kV / cm. When x = 0.4, the frequency is 0.1Hz, the maximum strain of (Na 0.5 Bi 0.5 ) 0.45 Sr 0.15 Pb 0.4 TiO3 reaches 2.77%, and the strain memory effect is 1.75%.

Claims

1. A ternary ceramic material of sodium bismuth titanate- strontium titanate-lead titanate with high strain performance obtained by reduction with bismuth, characterized in that The chemical composition general formula of the ternary ceramic material of sodium bismuth titanate-strontium titanate-lead titanate with high strain performance obtained by reduction of bismuth is (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3, wherein x=0.05~0.4; the ternary ceramic material of sodium bismuth titanate-strontium titanate-lead titanate is mixed by Na2CO3, SrCO3, TiO2, Bi2O3 and PbO in stoichiometric ratio (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3, and then formed by pressing and sintering.

2. The ternary ceramic material of sodium bismuth titanate- strontium titanate-lead titanate with high strain performance obtained by reduction with bismuth according to claim 1, characterized in that Chemical composition general formula (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3 wherein x = 0.2 to 0.

4.

3. The method of claim 1, wherein the Bi-reduced ternary ceramic material of sodium bismuth titanate- strontium titanate-lead titanate having high strain performance is prepared by the steps of: preparing a ternary ceramic material of sodium bismuth titanate- strontium titanate-lead titanate; and reducing the ternary ceramic material of sodium bismuth titanate- strontium titanate-lead titanate with Bi. The preparation method is realized according to the following steps: I. Ingredients: stoichiometric ratio (Na 0.5 Bi 0.5 ) 0.75(1-x) Sr 0.25(1-x) Pb x TiO3Na2CO3, SrCO3, TiO2, Bi2O3, and PbO were weighed as raw materials; II. Ball milling: Put the raw materials of step I into a ball mill tank for ball milling treatment, and obtain mixed powder after drying; III. Pre-sintering: Pre-sintering treatment is performed on the mixed powder at a temperature of 850~950℃, and the pre-sintered powder is obtained; IV. Secondary ball milling: Put the pre-sintered powder into the ball mill tank again for secondary ball milling treatment, and obtain the ball-mixed powder after drying; V. Granulation: Grind and sieve the ball-mixed powder, then add a binder and grind thoroughly to granulate, and obtain the granulated powder; VI. Shaping: Put the granulated powder into a mold and press into a sheet-shaped material; VII. Glue removal: Heat treatment is performed on the sheet-shaped material at a temperature of 500~600℃ using a sintering furnace to remove glue, and obtain the ceramic sheet after glue removal; VIII. Sintering: Sintering treatment is performed on the ceramic sheet after glue removal at a temperature of 1130~1150℃, and obtain the ternary ceramic material; IX. Electrode plating: Polish both sides of the ternary ceramic material, then evenly apply conductive silver paste on both sides of the ceramic, and perform annealing treatment at 500~600℃ after drying, and obtain the ceramic sheet with silver electrodes; X. Electric field pretreatment: Put the ceramic sheet with silver electrodes into an electric field of 40~70 kV / cm for polarization treatment, and obtain the sodium bismuth titanate-strontium titanate-lead titanate ternary ceramic material with high strain performance.

4. The method for preparing a sodium bismuth titanate- strontium titanate-lead titanate ternary ceramic material having high strain performance obtained by reduction with bismuth according to claim 3, characterized in that The ball milling treatment in step II is performed at a speed of 200 r / min for 10~12h.

5. The method for preparing a sodium bismuth titanate-strontium titanate-lead titanate ternary ceramic material having high strain performance obtained by reduction with bismuth according to claim 3, characterized in that The pre-sintering treatment time in step III is 2~6h.

6. The method for preparing a sodium bismuth titanate-strontium titanate-lead titanate ternary ceramic material having high strain performance obtained by reduction with bismuth according to claim 3, characterized in that The binder in step V is 5wt.% polyvinyl alcohol.

7. The method for preparing a sodium bismuth titanate-strontium titanate-lead titanate ternary ceramic material having high strain performance obtained by reduction with bismuth according to claim 3, characterized by The heat treatment glue removal time in step VII is 1~2h.

8. The method for preparing a sodium bismuth titanate-strontium titanate-lead titanate ternary ceramic material having high strain performance obtained by reduction with bismuth according to claim 3, characterized in that The sintering treatment time in step VIII is 3~3.5h.

9. The method for preparing a sodium bismuth titanate-strontium titanate-lead titanate ternary ceramic material having high strain performance obtained by reduction with bismuth according to claim 3, characterized in that The annealing treatment time in step IX is 0.4~0.8h.

10. The method for preparing a sodium bismuth titanate-strontium titanate-lead titanate ternary ceramic material having high strain performance obtained by reduction with bismuth according to claim 3, characterized by The ceramic sheet with silver electrodes is placed in an electric field of 40~70 kV / cm for polarization treatment for 50~70s in step X.

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