CN102683576B - Piezoelectric actuator and manufacturing method thereof - Google Patents

Abstract

The invention provides a piezoelectric driver manufacturing method and the piezoelectric driver. The method includes: making internal electrodes with preset patterns on the upper and lower surfaces of the piezoelectric ceramic sheets; bonding the plurality of piezoelectric ceramic sheets after the internal electrodes are made to form an integrated body through a high-temperature-resistant inorganic polymerized silicon gel material Multilayer ceramics with multilayer ceramic structure; external electrodes are respectively made on two opposite sides of the multilayer ceramics with integrated structure, so as to form parallel connection of each piezoelectric ceramic sheet on the circuit; for the integrated structure Multilayer ceramics are polarized to obtain the piezoelectric actuator. The piezoelectric driver of the invention is simple to manufacture, has better high temperature resistance performance, and works stably and reliably.

Description

Manufacturing method of piezoelectric driver and piezoelectric driver

technical field

The invention relates to piezoelectric driver technology, in particular to a manufacturing method of a piezoelectric driver and a piezoelectric driver.

Background technique

Piezoelectric actuators, such as piezoelectric ceramic micro-actuators, are new solid-state actuators made using the inverse piezoelectric effect of piezoelectric materials. They have the advantages of small size, good linearity, convenient control, high displacement resolution, good frequency response, and With the advantages of low power consumption and no noise, it has been widely used in high-tech fields such as precision optics, micro-mechanics, and microelectronics.

Among them, according to different driving methods, piezoelectric actuators can be divided into rigid displacement actuators and resonant displacement actuators. ) drivers and cymbals (Cymbals) drivers, etc. Due to the advantages of large bearing capacity, fast response speed, good displacement repeatability, high volumetric efficiency, and relatively simple electric field control, the multilayer actuator is a common piezoelectric actuator and has been widely used in the field of precision machinery.

At present, the production of multi-layer drives usually adopts the traditional film-casting and multi-layer co-firing preparation process, which includes the following steps: (1) Tape casting, which is to make a slurry after adding an organic solvent to the raw material, and Slurry casting to obtain the film layer; (2) drying, that is, drying the film layer obtained by casting; (3) stacking, coating the dried film layer with silver electrodes, and superimposing; (4) total Sintering, that is, calcining the multilayer film obtained after stacking at a high temperature to obtain a piezoelectric actuator with a multilayer structure. In the existing multi-layer co-firing preparation process using traditional cast film formation, organic solvents are required, and organic solvents are usually poisonous; during the co-firing process, the silver electrodes plated on the film layer are easy to diffuse, resulting in poor performance of the piezoelectric actuator after fabrication. decrease and degradation; at the same time, the existing preparation process is complicated, the safety is poor, and the production cost is high. In addition, in the prior art, a piezoelectric driver is also obtained by using an epoxy resin paste method.

In summary, in the existing multi-layer co-firing preparation process of piezoelectric actuators, the silver electrode on the film layer is likely to diffuse during the multi-layer co-firing process, and creep is easy to occur between piezoelectric ceramic layers, which makes the energy conversion of piezoelectric actuators difficult. The efficiency is low, the displacement loss is large, and the performance of the piezoelectric actuator is poor; in addition, the preparation process of the existing piezoelectric actuator is complicated, and the quality is not easy to control. However, when an epoxy resin is used to prepare a piezoelectric driver, the prepared piezoelectric driver cannot work in a high-temperature environment.

Contents of the invention

The present invention provides a method for manufacturing a piezoelectric driver and a piezoelectric driver, which can effectively overcome the existing problems of piezoelectric drivers prepared by co-firing and epoxy resin in the prior art. On the premise of simplifying the preparation process of piezoelectric drivers, The driving performance of the piezoelectric driver can be effectively improved and the application range of the working temperature can be increased.

The invention provides a method for manufacturing a piezoelectric driver, comprising:

Make internal electrodes with preset patterns on the upper and lower surfaces of the piezoelectric ceramic sheet;

Through the high-temperature resistant inorganic polymeric silica gel material, the multiple piezoelectric ceramic sheets after making the internal electrodes are bonded together to form an integrated multi-layer ceramic;

Making external electrodes respectively on two opposite sides of the multilayer ceramic of the integrated structure, so as to form a parallel connection of each piezoelectric ceramic sheet on the circuit;

The multilayer ceramic of the integrated structure is polarized to obtain the piezoelectric driver.

In the above-mentioned manufacturing method of the piezoelectric actuator, the high temperature resistant inorganic polymeric silicon gel is formed by mixing magnesium silicate, aluminum phosphate and inorganic high molecular polymer.

In the above manufacturing method of the piezoelectric actuator, the high temperature resistant inorganic polymeric silicone gel is an inorganic polymeric silicone gel resistant to high temperatures above 500°C.

In the above manufacturing method of the piezoelectric actuator, the piezoelectric ceramic sheet is made of a piezoelectric material with a Curie temperature higher than 120°C.

In the above-mentioned piezoelectric actuator manufacturing method, an example of the piezoelectric ceramic sheet material is to use bismuth scandate-lead titanate solid solution, and the chemical formula of the bismuth scandate-lead titanate solid solution is (1-x)BiScO3- xPbTiO3, where: 0.2≤x<1.

In the manufacturing method of the above-mentioned piezoelectric actuator, before the electrodes of the preset pattern are respectively made on the upper and lower surfaces of the piezoelectric ceramic sheet, it also includes:

The piezoelectric ceramic sheet was prepared by solid state reaction method.

In the manufacturing method of the above-mentioned piezoelectric actuator, the electrode width w on the upper and lower surfaces of the piezoelectric ceramic sheet is smaller than the width W of the ceramic sheet, and the electrodes on the upper and lower surfaces are arranged anti-symmetrically on opposite sides;

The gap d=W-w from the electrode on any surface of the ceramic sheet to the side, and the gap d is greater than the thickness t of the piezoelectric ceramic sheet.

In the above manufacturing method of the piezoelectric actuator, the inner electrode and the outer electrode are both silver electrodes. Wherein, the internal electrode and the external electrode are formed by firing, and the firing temperature is 500°C-900°C. The internal electrodes can also be copper, nickel or gold, or their mixed electrodes; the internal electrodes can also be prepared by sputtering.

In addition, the present invention also provides a piezoelectric driver, which is manufactured by using the manufacturing method of the piezoelectric driver provided in the present invention.

The manufacturing method of the piezoelectric actuator and the piezoelectric actuator provided by the present invention are bonded by high-temperature-resistant inorganic polymer silicon gel, avoiding the problem of the decrease and degradation of the piezoelectric performance caused by the diffusion of silver electrodes in the traditional multi-layer co-firing method, and at the same time , can also avoid the inherent defect that the traditional epoxy resin bonding method cannot withstand high temperature, eliminate the creep between the piezoelectric ceramic sheets, and can effectively improve the energy conversion efficiency of the piezoelectric actuator, and the obtained high-temperature piezoelectric actuator has more Excellent electrical properties and better consistency. The manufacturing method of the piezoelectric driver provided by the invention has the advantages of simple manufacturing process and low cost, and can prepare a piezoelectric driver suitable for working in a high-temperature environment, and the quality of the manufactured piezoelectric driver is stable and reliable.

Description of drawings

FIG. 1 is a schematic flow chart of a manufacturing method of a piezoelectric driver provided by Embodiment 1 of the present invention;

2 is a schematic diagram of a method for preparing a piezoelectric ceramic sheet in an embodiment of the present invention;

Fig. 3 is the measured voltage-micro-displacement graph of the piezoelectric driver made according to the present invention;

FIG. 4 is a schematic structural diagram of a piezoelectric driver provided by Embodiment 2 of the present invention.

Detailed ways

In view of the problems existing in the existing piezoelectric actuators, an embodiment of the present invention provides a piezoelectric actuator in which a plurality of piezoelectric ceramic sheets can be alternately stacked and bonded in parallel to form a piezoelectric actuator with an integrated multi-layer structure. The manufacturing method of the piezoelectric driver and the structure of the piezoelectric driver of this embodiment will be described below.

FIG. 1 is a schematic flowchart of a manufacturing method of a piezoelectric driver provided by Embodiment 1 of the present invention. As shown in Figure 1, the manufacturing method of the piezoelectric driver of this embodiment may include the following steps:

Step 101, making internal electrodes with preset patterns on the upper and lower surfaces of the piezoelectric ceramic sheet;

Step 102, using a high-temperature resistant inorganic polymeric silica gel material to bond together the multiple piezoelectric ceramic sheets after the inner electrodes are made to form a multilayer ceramic with an integrated structure;

Step 103, making external electrodes on the two opposite sides of the multilayer ceramic with an integrated structure, so as to form a parallel connection of each piezoelectric ceramic sheet on the circuit;

Step 104 , polarizing the multilayer ceramic with an integrated structure to obtain a piezoelectric driver.

In this embodiment, when manufacturing piezoelectric actuators, multiple piezoelectric ceramic sheets can be bonded together through high-temperature-resistant inorganic polymeric silicon gel, which avoids the existing problems in the manufacture of piezoelectric actuators by the co-firing process, and simplifies The manufacturing process of the piezoelectric actuator is improved, the efficiency of the piezoelectric actuator is improved, and the manufacturing cost is reduced; at the same time, the piezoelectric ceramic sheets are bonded together by using high-temperature-resistant inorganic polymer silicon gel material, eliminating the gap between the piezoelectric ceramic sheets. The creep between them can effectively improve the performance of the manufactured piezoelectric actuator, and can effectively improve the energy conversion efficiency; in addition, by using high-temperature-resistant inorganic polymerized silica gel as a binder, the piezoelectric actuator can be effectively improved to work at high temperatures The reliability is suitable for the application requirements in high temperature environment.

In this embodiment, the high-temperature-resistant inorganic polymeric silica gel may be an inorganic polymeric silica gel resistant to high temperatures above 500° C., for example, it may be formed by mixing magnesium silicate, aluminum phosphate and inorganic polymers. Specifically, fine inorganic particles such as magnesium silicate and aluminum phosphate can be mixed with inorganic polymers to form an inorganic binder, which can have strong bonding strength and good high temperature resistance, so it can be used as a High temperature inorganic polymeric silicone gel bonding material.

In this embodiment, the piezoelectric ceramic sheet can be made of a piezoelectric material with a Curie temperature higher than 120°C. Specifically, in this embodiment, the piezoelectric ceramic sheet has a Curie temperature of 400-500°C. between. Specifically, the material for making the piezoelectric ceramic sheet can be bismuth scandate-lead titanate solid solution, and the chemical formula of the bismuth scandate-lead titanate solid solution can be expressed as (1-x)BiScO3-xPbTiO3, wherein: 0.2≤x< 1.

In this embodiment, the piezoelectric ceramic sheet can be prepared by a solid-state reaction method. Specifically, before the above-mentioned step 101, the piezoelectric ceramic sheet can be prepared by a solid-state reaction method. The bismuth scandate-titanic acid The process of preparing piezoelectric ceramic sheet from lead solid solution is described.

Fig. 2 is a schematic diagram of the preparation method of the piezoelectric ceramic sheet in the embodiment of the present invention. As shown in Figure 2, the preparation process of the piezoelectric ceramic sheet may include the following steps:

Step 201, determine the material for making the piezoelectric ceramic sheet, and perform batching.

Specifically, the chemical formula of the bismuth scandate-lead titanate solid solution, which is the material for making piezoelectric ceramic sheets, was determined, and the material for making piezoelectric ceramic sheets was obtained by weighing and batching according to the stoichiometric ratio of the chemical formula.

In this embodiment, a bismuth scandate-lead titanate solid solution with a chemical formula of 0.633BiScO3-0.367PbTiO3 is used. When preparing the solid solution, Bi2O3, Sc2O3, PbO and TiO2 powders with a purity greater than 99.9% are used, and are measured according to the chemical formula Specific weighing, mixing, and configuration to obtain several grams of powder; in the powder obtained by mixing, add an appropriate amount of absolute ethanol as a ball milling agent, and use zirconia balls as a ball milling medium, and the weight ratio of the three is powder: zirconia Ball: ethanol = 1: 1.5: 1; put it in a ball mill for 24 hours to make the oxides fully mixed and ground.

Step 202, calcining the oxide mixture obtained by grinding in the above step 201 to obtain a solid solution powder.

Specifically, the mixture obtained after grinding in the above step 201 can be first dried at 80°C, then the temperature is raised to 450°C at a rate of 5°C/min, kept for 2 hours, and then heated to 750°C at the same rate, kept for 4 hours , to form a solid solution powder with a certain crystal structure; then, ball mill the powder for 24 hours to refine the particles; finally, perform secondary calcination and ball mill again to obtain a solid solution powder with fine and uniform particles.

In this step, the oxide mixture is calcined at 750° C. for 4 hours, so that a solid-phase chemical reaction occurs between the oxides to form a solid solution powder with a perovskite crystal structure.

Step 203, molding the solid solution powder obtained in the above step 202 to obtain a green body.

Specifically, take out the solid solution powder obtained in the above step 202, add 3% polyvinyl alcohol binder, mix thoroughly, granulate and pass through an 80-mesh sieve, take out an appropriate amount of powder and put it into a mold, and shape it under a pressure of 120MPa , to obtain a square green body of the required size.

In this step, passing through an 80-mesh sieve can effectively improve the fluidity and compression performance of the obtained particles, and can be unidirectionally pressed and formed under a pressure of 120 MPa to obtain a green body.

Step 204 , continue to calcine the green body obtained in the above step 203 to obtain bismuth scandate-lead titanate solid solution ceramics.

Specifically, the square biscuit obtained in the above step 203 was heated up to 450°C at a rate of 1°C/min, kept at a temperature of 3 hours, then raised to 600°C at a rate of 2°C/min, kept at a temperature of 3 hours, and then cooled in a furnace. The process can fully eliminate the organic matter of polyvinyl alcohol binder in the green body. Then, place the biscuit in a sealed crucible, raise the temperature to 1050-1150°C at a rate of 5°C/min, and keep it warm for 60-180 minutes; then cool down with the furnace, and finally obtain a shrunk ceramic sheet with a shrinkage rate of 18%. It is dense and uniform bismuth scandate-lead titanate solid solution ceramics.

In this step, the binder organic matter contained in the biscuit is firstly removed, and then sintered at 1050-1150° C., so that dense and uniform bismuth scandate-lead titanate solid solution ceramics can be obtained.

Step 205 , processing the solid solution ceramic obtained in the above step 204 to obtain a ceramic sheet with a thickness of 0.1-10 mm.

Specifically, the square ceramics obtained in the above step 204 can be polished, ultrasonically cleaned, dried and other processes to make sintered and dense piezoelectric ceramics into ceramic sheets with a thickness of 0.1-10 mm.

According to step 201-step 205, the required number of piezoelectric ceramic sheets can be prepared. In practical applications, thinner piezoelectric ceramic sheets, such as piezoelectric ceramic sheets of 0.02mm-0.2mm, can also be prepared by using a membrane-bonding method as required.

After the ceramic sheet with a certain thickness is obtained through the above steps, the piezoelectric actuator can be fabricated according to the steps shown in FIG. 1 . Specifically, in this embodiment, the thickness of the piezoelectric ceramic sheet made is 1mm; the conductive material in the inner electrode made on the surface of the piezoelectric ceramic sheet is silver with a weight ratio of 100%, wherein the performance parameter of the silver material is : Piezoelectric constant d33=441pC/N, dielectric constant ε=1051, dielectric loss tanθ=3%, radial electromechanical coupling coefficient kp=0.58. In addition, the external electrodes fired or sputtered on the two opposite sides of the integral structure formed by bonding piezoelectric ceramic sheets are also silver electrodes.

In this embodiment, the inner electrode and the outer electrode are made by firing, and the firing temperature is 500°C-900°C, so that when the silver electrode is made, the mutual penetration between the electrode and the ceramic can be reduced, and the reliability of the device can be improved. sex. Moreover, compared with the prior use of silver-palladium electrodes, it has the advantage of low cost. In addition, in this embodiment, the internal electrode and the external electrode can also use other metal electrodes, such as copper electrodes, nickel electrodes, gold electrodes, etc., or they can also be mixed metals mixed with two or more metals such as silver, copper, nickel, and gold. The electrodes are not particularly limited in this embodiment.

In practical applications, the thickness of the piezoelectric ceramic sheet obtained through steps 201-step 205 can be between 0.02-10 mm according to needs to meet actual needs; in addition, the width of the internal electrode on the piezoelectric ceramic sheet is smaller than that of the piezoelectric ceramic sheet width to ensure the work performance of the manufactured piezoelectric actuator.

In practical applications, an appropriate number of piezoelectric ceramic sheets can be set to form a piezoelectric driver with an integrated structure according to needs. For example, the number of piezoelectric ceramic sheets can be between 2 and 1000. In this embodiment, the piezoelectric ceramic sheets The quantity is 10.

In this embodiment, in order to ensure the working performance of the piezoelectric actuator, the inner electrodes made on the upper and lower surfaces of each piezoelectric ceramic sheet have the same electrode pattern size and shape, but are anti-symmetrically arranged; one end of the piezoelectric ceramic sheet is connected to the outer electrode. The electrodes are electrically connected, and the other end is electrically isolated from the external electrode through the piezoelectric ceramic region itself that is not coated with electrodes, and among the two adjacent ceramic sheets, the end connected to the external electrode is arranged alternately, so that the multilayer ceramic of the integrated structure In the above, each piezoelectric ceramic sheet can be connected in parallel on the circuit.

In practical applications, the pattern of the internal electrodes made on the piezoelectric ceramic sheet can be set to a suitable pattern according to the needs. In this embodiment, the size and shape of the internal electrode patterns made on the upper surface and the lower surface of the piezoelectric ceramic sheet are consistent, and one end It is flush with one side of the piezoelectric ceramic sheet, and has a certain distance gap between one end and one side of the piezoelectric ceramic sheet, so that the two internal electrodes on the upper and lower surfaces are arranged antisymmetrically and alternately. In this way, multiple ceramic sheets are alternately stacked so that the internal electrodes on two adjacent piezoelectric ceramic sheets can be respectively adjacent to the external electrodes on both sides, and the piezoelectric ceramic sheets are connected in parallel on the circuit. In order to avoid insufficient thickness polarization of the piezoelectric ceramic sheet, the electrode width w on the upper and lower surfaces of the piezoelectric ceramic sheet is smaller than the width W of the ceramic sheet, and the upper and lower electrodes are arranged against symmetrical end faces; the electrodes on any surface of the ceramic sheet are connected to the side The gap d=W-w should be greater than the thickness t of the piezoelectric ceramic sheet. In this embodiment, as shown in FIG. 4, the overall thickness of the piezoelectric ceramic sheet 101 is L, the electrode width w on the upper and lower surfaces is smaller than the width W of the piezoelectric ceramic sheet 101, and the electrodes on the upper and lower surfaces are arranged antisymmetrically on opposite sides; The gap d=W-w from the electrode on any surface of the piezoelectric ceramic sheet 101 to the side, and the gap d is greater than the thickness t of the piezoelectric ceramic sheet.

Fig. 3 is a voltage-micro-displacement curve graph measured by a piezoelectric driver manufactured according to the present invention. As shown in Figure 3, where the abscissa is the electric field strength, and the ordinate is the micro-displacement, it can be seen that as the temperature increases, under the same test electric field strength, the displacement of the piezoelectric actuator manufactured according to the embodiment of the present invention increases , and can work stably at 200°C.

The manufacturing method of the piezoelectric actuator provided by the present invention avoids the problem of the decrease and degradation of the piezoelectric performance caused by the diffusion of the silver electrode in the traditional multi-layer co-firing method by using high-temperature-resistant inorganic polymeric silicon gel for bonding, and at the same time, it can also avoid The traditional epoxy resin bonding method cannot withstand the inherent defect of high temperature, which improves the electromechanical conversion efficiency, and the obtained high-temperature piezoelectric actuator has more excellent electrical properties and better consistency. The manufacturing method of the piezoelectric driver provided by the present invention has the advantages of simple manufacturing process and low cost, and can prepare a piezoelectric driver suitable for working in a high-temperature environment.

FIG. 4 is a schematic structural diagram of a piezoelectric driver provided by Embodiment 2 of the present invention. As shown in Figure 4, the piezoelectric actuator of this embodiment is produced by the method shown in Figure 1 above, the piezoelectric actuator 10 includes a multilayer piezoelectric ceramic sheet 101, and the upper and lower surfaces of each piezoelectric ceramic sheet 101 are provided with inner electrodes 102, and the opposite sides of the piezoelectric driver 10 are respectively provided with external electrodes 103, so that each piezoelectric ceramic sheet 101 is connected in parallel on the circuit, and each piezoelectric ceramic sheet 101 is polarized along the thickness direction, The polarization directions of two adjacent piezoelectric ceramic sheets are opposite, and its specific implementation can refer to the description of the method embodiment of the present invention above, and will not be repeated here.

The piezoelectric actuator of this embodiment can make each piezoelectric ceramic sheet elongate or shorten along the thickness direction under the action of an external voltage, thereby realizing the required displacement. The specific implementation process is the same or similar to that of the traditional piezoelectric actuator. This will not be repeated here.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (9)

1. A method for manufacturing a piezoelectric driver, comprising: Make internal electrodes with preset patterns on the upper and lower surfaces of the piezoelectric ceramic sheet; Through the high-temperature resistant inorganic polymeric silica gel material, the multiple piezoelectric ceramic sheets after making the internal electrodes are bonded together to form an integrated multi-layer ceramic; Making external electrodes respectively on two opposite sides of the multilayer ceramic of the integrated structure, so as to form a parallel connection of each piezoelectric ceramic sheet on the circuit; Polarizing the multilayer ceramic of the integrated structure to obtain the piezoelectric driver; Wherein, the high temperature resistant inorganic polymeric silica gel is formed by mixing magnesium silicate, aluminum phosphate and inorganic high molecular polymer. 2 . The manufacturing method of the piezoelectric actuator according to claim 1 , wherein the high temperature resistant inorganic polymeric silicone gel is an inorganic polymeric silicone gel resistant to high temperatures above 500° C. 3 . 3 . The manufacturing method of the piezoelectric actuator according to claim 2 , wherein the piezoelectric ceramic sheet is made of a piezoelectric material with a Curie temperature higher than 120° C. 4 . 4. The manufacturing method of the piezoelectric driver according to claim 3, wherein the material of the piezoelectric ceramic sheet is a bismuth scandate-lead titanate solid solution, and the chemical formula of the bismuth scandate-lead titanate solid solution is (1-x)BiScO ₃ -xPbTiO ₃ , where: 0.2≤x<1. 5. The manufacturing method of the piezoelectric actuator according to any one of claims 1-4, characterized in that, before the electrodes of the preset pattern are respectively made on the upper and lower surfaces of the piezoelectric ceramic sheet, the method further includes: The piezoelectric ceramic sheet was prepared by solid state reaction method. 6. The manufacturing method of the piezoelectric actuator according to claim 1, wherein the electrode width w on the upper and lower surfaces of the piezoelectric ceramic sheet is smaller than the width W of the ceramic sheet, and the opposite sides of the electrodes on the upper and lower surfaces are arranged antisymmetrically; The gap d=W-w from the electrode on any surface of the ceramic sheet to the side, and the gap d is greater than the thickness t of the piezoelectric ceramic sheet. 7. The manufacturing method of the piezoelectric actuator according to claim 1, wherein the inner electrode and the outer electrode are silver electrodes, copper electrodes, nickel electrodes, gold electrodes or mixed metal electrodes in which at least two metals are mixed. 8 . The manufacturing method of the piezoelectric actuator according to claim 7 , wherein the inner electrode and the outer electrode are formed by firing or sputtering. 9. A piezoelectric driver manufactured by the manufacturing method of the piezoelectric driver according to any one of claims 1-8.

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