Method for producing piezoelectric material and use thereof

Abstract

The application belongs to the technical field of electronic materials, and particularly relates to a preparation method and application of a piezoelectric material. The preparation method of the piezoelectric material comprises the following steps: (1) mixing a ceramic material and an alkaline solution to obtain a mixed solution; (2) grinding and drying the mixed solution to obtain the piezoelectric material; the alkaline solution is alkaline water; the pH of the alkaline solution is 11-14. The alkaline water with the pH of 11-14 is adopted, the hydroxyl radical in the alkaline water provides an alkaline water environment, has better surface tension, and the metal ions in the ceramic material combined with the hydroxyl radical have a good agglomeration effect on water molecules, so that the ceramic material particles can be uniformly dispersed to the nanometer level in the grinding process. In addition, the introduction of the alkaline water environment can also optimize the size of the piezoelectric material nanoparticles, and finally the piezoelectric material with good uniformity and dispersity is obtained, and the prepared piezoelectric film has good ferroelectric and piezoelectric properties.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electronic materials, and particularly relates to a preparation method of piezoelectric material and application. BACKGROUND

[0002] Piezoelectric material is a material with piezoelectricity and mechanical conversion. Due to a series of important properties such as light, electricity, heat and sound, and the advantages of small volume, low working voltage, easy development of small devices and integration with semiconductor process, piezoelectric material has a wide application prospect in the fields of microelectronics, optoelectronics, integrated optics, micromechanics and microelectromechanics.

[0003] With the improvement of piezoelectric material preparation technology, research method and testing means, the performance of piezoelectric material has been greatly improved. However, there are still some problems in the research process, (1) the piezoelectric material currently applied to electronic devices is mainly lead-based piezoelectric material, but the lead-based piezoelectric material will cause serious environmental pollution in the preparation and processing process. Based on the concept of green environmental protection, lead-free or lead-free piezoelectric materials such as barium titanate appear. It has good piezoelectricity and ferroelectricity. These characteristics are very beneficial to the preparation of piezoelectric thin film integrated devices, but the barium titanate particle raw material has the problems of poor dispersibility and uniformity; (2) the piezoelectric material prepared at present usually has low insulation and high dielectric loss, which greatly shortens the service life of the piezoelectric material; (3) the piezoelectric material is usually prepared by hydrothermal method in the preparation process, which will produce impurities and the uniformity and dispersibility of the prepared raw material particles are poor. Although some studies have prepared barium titanate particles with small particle size by using corresponding mechanical method, the cost of the equipment required is high.

[0004] Therefore, it is urgent to provide a preparation method of piezoelectric material, which has simple process, low cost, and the prepared piezoelectric material has good dispersibility and uniformity, so that the prepared piezoelectric thin film has good ferroelectric and piezoelectric properties. SUMMARY

[0005] The present application aims to solve one or more technical problems in the prior art, and at least provide a beneficial choice or create conditions. Specifically, the present application provides a preparation method of piezoelectric material, which has simple process, low cost, and the prepared piezoelectric material has good dispersibility and uniformity, so that the prepared piezoelectric thin film has good ferroelectric and piezoelectric properties.

[0006] The inventive concept of the present application: the preparation method of the piezoelectric material, comprising the following steps: firstly, mixing ceramic material and alkaline solution to obtain a mixed solution; then, grinding and drying the mixed solution to obtain the piezoelectric material; the alkaline solution is alkaline water; the pH of the alkaline solution is 11-14. The present application uses alkaline water with pH of 11-14, the hydroxide in the alkaline water provides an alkaline water environment, has better surface tension, and the metal ions (potassium ions and sodium ions, etc.) combined with the hydroxide have good agglomeration effect on water molecules, which can make the ceramic material particles uniformly dispersed to nanoscale level under the agglomeration of water molecules during the grinding process. In addition, the introduction of the alkaline water environment can also optimize the size of the ceramic material nanoparticles, and finally obtain the piezoelectric material with good uniformity and dispersity, and the prepared piezoelectric film has good ferroelectric and piezoelectric properties.

[0007] Therefore, the first aspect of the present application provides a preparation method of a piezoelectric material.

[0008] Specifically, the preparation method of the piezoelectric material comprises the following steps:

[0009] (1) mixing ceramic material and alkaline solution to obtain a mixed solution;

[0010] (2) grinding and drying the mixed solution obtained in step (1) to obtain the piezoelectric material;

[0011] The alkaline solution is alkaline water; the pH of the alkaline solution is 11-14.

[0012] Preferably, the pH of the alkaline solution is 12-14; further preferably, the pH of the alkaline solution is 13.

[0013] Preferably, the ceramic material comprises at least one of barium titanate, magnesium titanate, calcium titanate, strontium titanate, silicon carbide, aluminum nitride, zinc oxide, gallium oxide, superconductor, and perovskite material.

[0014] Preferably, in step (1), the use amount ratio of the ceramic material to the alkaline solution is 3g:(8-12)mL; further preferably, the use amount ratio of the ceramic material to the alkaline solution is 3g:(9-11)mL; more preferably, the use amount ratio of the ceramic material to the alkaline solution is 3g:10mL.

[0015] Preferably, in step (2), the rotation speed of the grinding is 2200-3000 revolutions per minute, and the grinding time is 0.5-2.5h; further preferably, the rotation speed of the grinding is 2500-2800 revolutions per minute, and the grinding time is 1-2h; more preferably, the rotation speed of the grinding is 2600-2700 revolutions per minute, and the grinding time is 1.5h.

[0016] Preferably, in step (2), the temperature of the drying is 70-90℃; further preferably, the temperature of the drying is 75-85℃; more further preferably, the temperature of the drying is 80℃.

[0017] Preferably, the particle size of the piezoelectric material is 9-33nm; further preferably, the particle size of the piezoelectric material is 10-30nm.

[0018] Specifically, before grinding, the grinder and the water cooling device need to be turned on, because mechanical grinding will generate high temperature, and water cooling is needed to maintain the temperature stability.

[0019] Preferably, the preparation method of the alkaline solution comprises the following steps:

[0020] The electrolyte and electrolytic water are mixed, electrolyzed, and the alkaline solution is prepared.

[0021] Specifically, the alkaline solution is prepared by using an electrolytic water machine.

[0022] Preferably, the electrolyte and electrolytic water are first placed in the corresponding box of the electrolytic water machine, and then the pump is turned on to circulate the electrolyte and electrolytic water, electrolyze, and prepare the alkaline solution.

[0023] Preferably, the electrolyte comprises at least one of potassium carbonate, potassium bicarbonate, and sodium carbonate.

[0024] Preferably, the electrolytic water comprises pure water.

[0025] Preferably, when circulating, the flow rate of the electrolyte is 6-10L / h; further preferably, the flow rate of the electrolyte is 7-9L / h; more further preferably, the flow rate of the electrolyte is 8L / h.

[0026] Preferably, when circulating, the flow rate of the electrolytic water is 3-5L / h; further preferably, the flow rate of the electrolyte is 3.5-4.5L / h; more further preferably, the flow rate of the electrolyte is 4L / h.

[0027] Specifically, the current and voltage need to be adjusted during electrolysis.

[0028] Preferably, the current during electrolysis is 4-6 amperes; further preferably, the current during electrolysis is 4.5-5.5 amperes; more further preferably, the current during electrolysis is 5 amperes.

[0029] Preferably, during the electrolysis process, the pH of the electrolytic water in the pure water tank can be measured, and when the pH is 11-14, the electrolytic water machine is turned off, and the electrolysis is completed.

[0030] The second aspect of the present application provides a piezoelectric thin film.

[0031] Specifically, the piezoelectric thin film comprises the piezoelectric material prepared by the preparation method of the piezoelectric material according to the first aspect of the present application.

[0032] The third aspect of the present application provides a preparation method of the piezoelectric thin film according to the second aspect of the present application.

[0033] Specifically, the preparation method of the piezoelectric thin film comprises the following steps:

[0034] The piezoelectric material is spin-coated and sintered to obtain the piezoelectric thin film.

[0035] Preferably, the aqueous solution of the piezoelectric material is spin-coated and sintered to obtain the piezoelectric thin film.

[0036] Preferably, the sintering temperature is 1000-2000℃; further preferably, the sintering temperature is 1200-1800℃.

[0037] Compared with the prior art, the technical solution provided by the present application has the following beneficial effects:

[0038] (1) The ceramic material and the alkaline solution are mixed to obtain a mixed solution; then the mixed solution is ground and dried to obtain the piezoelectric material; the alkaline solution is alkaline water; the pH of the alkaline solution is 11-14. In the present application, the alkaline water with a pH of 11-14 provides an alkaline water environment, has better surface tension, and the metal ions in the ceramic material combined with the hydroxyl ions in the alkaline water have a good agglomeration effect on water molecules. Under the agglomeration effect of water molecules, the ceramic material particles can be uniformly dispersed to the nanometer level during the grinding process. In addition, the introduction of the alkaline water environment can also optimize the size of the ceramic material nanoparticles, and ultimately obtain a piezoelectric material with good uniformity and dispersity, and the prepared piezoelectric thin film has good ferroelectric and piezoelectric properties.

[0039] (2) The piezoelectric material is prepared by the wet grinding method, and the selection of reasonable grinding parameters can further improve the dispersity and uniformity of the piezoelectric material nanoparticles, and the particle size of the piezoelectric material is 9-33nm, which can well meet the application requirements of large-area integrated circuits.

[0040] (3) The piezoelectric material of the present application does not contain lead, which overcomes the harm of lead-based piezoelectric materials to human beings and the ecological environment during production, use and disposal, and is more green and environmentally friendly. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 X-ray powder diffraction pattern of the piezoelectric material of Example 1 and Comparative Example 1 of the present application;

[0042] Figure 2 X-ray powder diffraction standard pattern of barium titanate;

[0043] Figure 3 Scanning electron microscope image of piezoelectric material of Example 1 and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0044] In order to make the skilled in the art more clearly understand the technical solutions described in the present application, the following examples are listed for illustration. It should be pointed out that the following examples do not constitute a limitation on the scope of protection required by the present application.

[0045] The raw materials, reagents or devices used in the following examples, unless otherwise specified, can be obtained from conventional commercial channels, or can be obtained by existing known methods.

[0046] Example 1

[0047] A method for preparing a barium titanate piezoelectric material, comprising the following steps:

[0048] (1) 150g of barium titanate powder is added to 500ml of an alkaline aqueous solution with a pH of 13, and the barium titanate powder is fully dispersed by constant stirring to obtain a barium titanate aqueous solution;

[0049] (2) To avoid high temperature generated by mechanical grinding, first start the water cooling circulating machine and the nano-grinding machine, then add the barium titanate aqueous solution obtained in step (1) to the nano-grinding machine for grinding, the grinding speed is 2680r / min, and the grinding time is 1.5 hours, to obtain a ground barium titanate aqueous solution;

[0050] (3) The barium titanate aqueous solution obtained in step (2) is placed in an oven and dried at a temperature of 80℃ to remove the water, thereby obtaining a barium titanate piezoelectric material with a particle size of 10-30nm.

[0051] The preparation method of the alkaline aqueous solution with a pH of 13 comprises the following steps:

[0052] S1: Dissolve 1Kg of potassium carbonate in 8L of pure water, stir until the potassium carbonate is fully dissolved to obtain a potassium carbonate solution, which is used as an electrolyte for the preparation of the alkaline aqueous solution;

[0053] S2: Weigh 4 liters of pure water as the corresponding electrolytic water of the electrolyte, and put the pure water and the electrolyte obtained in step S1 into the corresponding box of the electrolytic water machine, start the pump to circulate the electrolyte and pure water, and at the same time start the water pump to control the flow rate of the electrolyte and the electrolytic water to be 8L / h and 4L / h respectively;

[0054] S3: Turn on the electrolytic water machine, adjust the current and voltage, the current is 5 amperes, the voltage is 10V, electrolyze for 2h, use a rubber dropper to extract the electrolytic water in the pure water tank and use a pH meter to measure the real-time pH every 5 minutes, turn off the electrolytic water machine when the pH = 13, and prepare an alkaline aqueous solution with a pH value of 13.

[0055] Example 2

[0056] A preparation method of a silicon carbide piezoelectric material, comprising the following steps:

[0057] (1) 150g of silicon carbide powder is added to 500ml of an alkaline aqueous solution with a pH of 12, and the silicon carbide powder is fully dispersed by constant stirring to obtain a silicon carbide aqueous solution;

[0058] (2) To avoid high temperature generated by mechanical grinding, first turn on the water cooling circulator and the nano-grinder, then add the silicon carbide aqueous solution obtained in step (1) to the nano-grinder, the grinding speed is 2750r / min, and the grinding time is 2.0 hours, to obtain a ground silicon carbide aqueous solution;

[0059] (3) The silicon carbide aqueous solution obtained in step (2) is placed in an oven and dried at a temperature of 90℃, to obtain a silicon carbide piezoelectric material with a particle size of 15-30nm.

[0060] The preparation method of the alkaline aqueous solution with a pH of 12 comprises the following steps:

[0061] S1: Dissolve 1Kg of potassium carbonate in 8L of pure water, stir uniformly to fully dissolve the potassium carbonate, to obtain a potassium carbonate solution as an electrolyte for electrolytic preparation of an alkaline aqueous solution;

[0062] S2: Weigh 4 liters of pure water as electrolytic water corresponding to the electrolyte, respectively put the pure water and the electrolyte into the corresponding tank of the electrolytic water machine, turn on the pump to circulate the electrolyte and the pure water, and at the same time turn on the water pump to control the flow rate of the electrolyte and the electrolytic water to be 8L / h and 4L / h respectively;

[0063] S3: Turn on the electrolytic water machine, adjust the current and voltage, the current is 5 amperes, the voltage is 10V, electrolyze for 2.5h, use a rubber dropper to extract the electrolytic water in the pure water tank and use a pH meter to measure the real-time pH every 5 minutes, and turn off the electrolytic water machine when the pH = 12, to prepare an alkaline aqueous solution with a pH value of 12.

[0064] Example 3

[0065] A preparation method of an aluminum nitride piezoelectric material, comprising the following steps:

[0066] (1) 150g of aluminum nitride powder is added to 500ml of an alkaline aqueous solution with a pH of 14, and the aluminum nitride powder is fully dispersed by constant stirring to obtain an aluminum nitride aqueous solution;

[0067] (2) To avoid high temperature generated by mechanical grinding, the water cooling circulation machine and the nano-grinding machine are first started, and then the aluminum nitride aqueous solution obtained in step (1) is added to the nano-grinding machine, the grinding speed is 2800r / min, and the grinding time is 2.5 hours, to obtain a ground aluminum nitride aqueous solution;

[0068] (3) The aluminum nitride aqueous solution obtained in step (2) is placed in an oven, and the water is dried at a temperature of 85℃, to obtain an aluminum nitride piezoelectric material with a particle size of 15-30nm.

[0069] The preparation method of the alkaline aqueous solution with a pH of 14 includes the following steps:

[0070] S1: Potassium carbonate is used as an electrolyte, 1kg of potassium carbonate is dissolved in 8L of pure water, and the potassium carbonate is fully dissolved by stirring to obtain a potassium carbonate solution, which is used as an electrolyte for preparing an alkaline aqueous solution by electrolysis;

[0071] S2: 4 liters of pure water are weighed as electrolytic water, and the pure water and the electrolyte are respectively placed in the corresponding box of the electrolytic water machine, and the pump is started to circulate the electrolyte and the pure water, and the water pump is started to control the flow rate of the electrolyte and the electrolytic water to be 8L / h and 4L / h respectively;

[0072] S3: The electrolytic water machine is started, the current and voltage are adjusted, the current is 5 amperes, the voltage is 10V, electrolysis is carried out for 3.0h, the electrolytic water in the pure water tank is extracted using a rubber dropper, the real-time pH is measured every 5 minutes using a pH meter, and the electrolytic water machine is turned off when the pH is 14, to obtain an alkaline aqueous solution with a pH of 14.

[0073] Comparative Example 1

[0074] The difference between Comparative Example 1 and Example 1 is only that Comparative Example 1 uses pure water with a pH of 7 instead of the alkaline aqueous solution with a pH of 13 in Example 1, and the other steps are the same as in Example 1.

[0075] Application Example 1

[0076] A preparation method of a piezoelectric thin film includes the following steps:

[0077] The barium titanate aqueous solution obtained in step (2) of Example 1 is prepared into a thin film by a high-speed spin coater, and then high-temperature sintering is carried out at a temperature of 1200℃ to obtain a barium titanate piezoelectric thin film.

[0078] Application Example 2

[0079] A method for preparing a piezoelectric thin film includes the following steps:

[0080] In Example 2, the silicon carbide aqueous solution obtained in step (2) was used to obtain a thin film by a high-speed spin coating machine, and then sintered at a high temperature of 1400°C to obtain a silicon carbide piezoelectric thin film.

[0081] Application Example 3

[0082] A method for preparing a piezoelectric thin film includes the following steps:

[0083] The aluminum nitride aqueous solution obtained in step (2) of Example 3 was used to obtain a thin film by a high-speed spin coating machine, and then sintered at a high temperature of 1500°C to obtain an aluminum nitride piezoelectric thin film.

[0084] Comparative Application Example 1

[0085] The preparation method of the piezoelectric thin film in Comparative Application Example 1 is the same as that in Application Example 1, the barium titanate aqueous solution ground in Comparative Example 1 is used.

[0086] Performance testing

[0087] 1. X-ray powder diffraction

[0088] X-ray powder diffraction tests were performed on the piezoelectric materials prepared in Example 1 and Comparative Example 1, and the results are as follows: Figure 1 As shown, Figure 1 In the figure, the horizontal axis 2theta (degree) represents the diffraction angle 2θ (°), the vertical axis Intensity (arb.units) represents the diffraction intensity, pH=13 represents the piezoelectric material prepared in Example 1, and pH=7 represents the piezoelectric material prepared in Comparative Example 1. Figure 2 This is the standard X-ray powder diffraction pattern of barium titanate, with standard PDF card number 34-0129.

[0089] Depend on Figure 1 and combined Figure 2 As can be seen from the standard PDF card, the characteristic peaks at the corresponding positions (110), (200), (211), and (310) are specifically displayed in Example 1 and Comparative Example 1, and are characteristic peaks of barium titanate.

[0090] 2. Scanning electron microscopy observation

[0091] Scanning electron microscopy was performed on the barium titanate piezoelectric materials prepared in Example 1 and Comparative Example 1, and the results are as follows: Figure 3 As shown, where, Figure 3 (a) is a scanning electron microscope image of the barium titanate piezoelectric material in Example 1. Figure 3(b) is a scanning electron microscope image of the barium titanate piezoelectric material of Comparative Example 1. The barium titanate piezoelectric material of Comparative Example 1 was prepared by the method of Comparative Example 1. Figure 3 It can be seen that the barium titanate piezoelectric material prepared in Example 1 is a nanoparticle, and the size is finer, and the dispersibility and uniformity are obviously better than those of the barium titanate piezoelectric material prepared in Comparative Example 1. It is illustrated that the use of the alkaline aqueous solution with a pH of 13 in Example 1 is beneficial to improve the dispersibility and uniformity of the piezoelectric material, and makes the particle size of the piezoelectric material finer.

[0092] 3. Performance test of piezoelectric thin film

[0093] The barium titanate piezoelectric thin films prepared in Application Example 1 and Comparative Application Example 1 were subjected to performance tests, and the test methods were as follows:

[0094] 1. Ferroelectric performance test: first, ceramic discs with uniform size (diameter of 12 mm and thickness of 1 mm) were prepared, a Radiant premier ii (ferroelectric test equipment) was connected to the test material, and the corresponding polarization intensity was tested by applying a voltage to the material.

[0095] 2. Piezoelectric performance test: a vertical pressure loading method was used for testing, a force F was applied to the barium titanate ceramic (BTO) thin film through a metal tip, and the BTO thin film generated an electric charge Q due to the piezoelectric effect; the generated electric charge was converted into a voltage V output through a parallel capacitor with the sample, and the voltage was measured by a voltmeter, and thus the piezoelectric coefficient d 33 .

[0096] The performance test results of the barium titanate piezoelectric thin films of Application Example 1 and Comparative Application Example 1 are shown in Table 1.

[0097] Table 1: Performance test results of barium titanate piezoelectric thin films of Application Example 1 and Comparative Application Example 1

[0098] Barium titanate piezoelectric thin film Maximum polarization P max (uC / cm 2 )]]> Remanent polarization P r (uC / cm 2 )]]> piezoelectric coefficient d 33 (pC / N) Application Example 1 3 1 180 Comparative Application Example 1 2.2 0.7 140

[0099] It can be seen from Table 1 that the maximum polarization, remanent polarization and piezoelectric coefficient of the barium titanate piezoelectric thin film prepared in Application Example 1 are all better than those of the barium titanate piezoelectric thin film prepared in Comparative Application Example 1, which illustrates that the barium titanate piezoelectric thin film prepared in Application Example 1 has good ferroelectric and piezoelectric properties.

[0100] To sum up, the application adopts the alkaline water with pH of 11-14, the hydroxyl radical in the alkaline water provides the alkaline water environment, has better surface tension, and the metal ion in the ceramic material combined with the hydroxyl radical has better agglomeration effect on the water molecules, under the agglomeration effect of the water molecules, the ceramic material particles can be uniformly dispersed to the nanometer level in the grinding process. In addition, the introduction of the alkaline water environment can also optimize the size of the piezoelectric material nanoparticles, and finally the piezoelectric material with good uniformity and dispersity is obtained, and the prepared piezoelectric thin film has good ferroelectric and piezoelectric properties.

[0101] The above examples are only used to illustrate the technical solutions of the application and not to limit the protection scope of the application. Although the application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the application can be modified or replaced equivalently without departing from the essence and scope of the technical solutions of the application.

Claims

1. A method for producing a piezoelectric material, characterized by, The method comprises the following steps: (1) mixing a ceramic material and an alkaline solution to obtain a mixed solution; (2) grinding and drying the mixed solution obtained in step (1) to obtain the piezoelectric material; the alkaline solution is alkaline water; the pH of the alkaline solution is 11-14; the ceramic material comprises at least one of barium titanate, magnesium titanate, calcium titanate, strontium titanate, silicon carbide, aluminum nitride, zinc oxide, gallium oxide, a superconductor, and a perovskite material; in step (2), the drying temperature is 70-90℃.

2. The production method according to claim 1, characterized by, in step (1), the amount ratio of the ceramic material to the alkaline solution is 3g:(8-12)mL.

3. The preparation method according to claim 1, characterized in that, in step (2), the grinding speed is 2200-3000rpm, and the grinding time is 0.5-2.5h.

4. The production method according to any one of claims 1 to 3, characterized by, the particle size of the piezoelectric material is 9-33nm.

5. The method of any one of claims 1-3, wherein, The preparation method of the alkaline solution comprises the following steps: mixing an electrolyte and electrolytic water, and electrolyzing to obtain the alkaline solution.

6. The production method according to claim 5, wherein the electrolyte comprises at least one of potassium carbonate, potassium bicarbonate, and sodium carbonate; and / or, the electrolytic water comprises pure water.

7. The preparation method according to claim 5, characterized in that, the current during electrolysis is 4-6 amperes.

8. A piezoelectric thin film, characterized by, The piezoelectric material is prepared by the preparation method of the piezoelectric material according to any one of claims 1-7.

9. The method for preparing the piezoelectric thin film according to claim 8, characterized in that, The method comprises the following steps: the piezoelectric material is spin-coated and sintered to obtain the piezoelectric film.

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