CN111908896A - Field-induced strain micro-displacement actuator and preparation method and application thereof - Google Patents

Abstract

The invention discloses a field-induced strain micro-displacement actuator and a preparation method and application thereof. The field induced strain micro-displacement actuator is formed by alternately stacking square piezoelectric ceramic sheets serving as displacement elements and square stainless steel metal sheets serving as extraction electrodes, wherein the square piezoelectric ceramic sheets have the chemical composition of Pb_0.9625Sm_0.025[(Mg_1/3Nb_2/3)_1‑xTi_x]O₃X is more than or equal to 0.28 and less than or equal to 0.31. The preparation method of the field induced strain micro-displacement actuator takes epoxy resin as a binder, a square piezoelectric ceramic sheet andthe square stainless steel metal sheets are alternately stacked and solidified. The field induced strain micro-displacement actuator prepared by the invention has large displacement output, small hysteresis and good repeated stability. Under the optimal condition, the displacement of the actuator with the length of 26.24mm under a room temperature 1kV driving electric field can reach 14.25 μm, and the device has wide application in the field of precision positioning.

Description

A field-induced strain micro-displacement actuator and its preparation method and application

technical field

The invention belongs to the technical field of micro-displacement actuators, and in particular relates to a field-induced strain micro-displacement actuator and a preparation method and application thereof.

Background technique

With the development of science and technology, nano-drive/positioning technology has become one of the key technologies in the field of cutting-edge science and engineering technology. Piezoelectric ceramic micro-displacement actuators have been widely used in many fields due to their small size, no heat, and high positioning accuracy, such as micro-displacement tool holders, precision micro-displacement systems, and precision positioning tables. The working principle of piezoelectric ceramic micro-displacement actuator is to use the inverse piezoelectric effect of piezoelectric ceramics. According to the first type of piezoelectric equation, the displacement of piezoelectric ceramics satisfies the following formula when an electric field is applied: S ₃ =d ₃₃ E ₃ , where S ₃ is the strain, d ₃₃ is the piezoelectric charge constant, and E is the electric field strength. _The larger the piezoelectric charge constant _d33 , the larger the S3. To obtain large strains, the material should have as large a value of _d33 as possible. In recent years, Li F et al. (Ultrahighpiezoelectricity in ferroelectric ceramics by design.Nature Materials.2018, 17(4):349-354) reported the samarium-doped lead magnesium niobate-lead titanate (Sm-PMN-xPT) system Electric ceramics can obtain ultra-high d ₃₃ values. On this basis, the inventor's research group obtained the strongest piezoelectric performance in the ceramic sheet with the composition of 0.025Sm-PMN-0.28PT by adjusting the size of x _. It reaches 1310pC/N, which creates conditions for the preparation of large-strain micro-displacement actuators.

At present, the most common method for preparing multi-layer micro-displacement actuators is to mix piezoelectric ceramic powders with organic solvents, cast them into ceramic diaphragms, and then alternately stack the ceramic diaphragms and internal electrodes. Fired multilayer piezoelectric ceramic actuators. The inner electrodes of such monolithic actuators are generally made of Pd or AgPd precious metal materials, which are expensive and keep the production cost high. In contrast, Ag electrodes are inexpensive, but it is difficult to achieve co-firing with ceramic materials due to their low melting point (961 °C). Therefore, the design and preparation of a field-induced strain micro-displacement actuator with better performance has become an urgent problem to be solved.

SUMMARY OF THE INVENTION

In order to solve the shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a field-induced strain micro-displacement actuator.

Another object of the present invention is to provide the above-mentioned preparation method of the field-induced strain micro-displacement actuator.

Another object of the present invention is to provide the application of the above-mentioned field-induced strain micro-displacement actuator.

The object of the present invention is achieved through the following technical solutions:

A field-induced strain micro-displacement actuator is formed by alternately stacking piezoelectric ceramic sheets and stainless steel metal sheets, wherein the chemical composition of the piezoelectric ceramic sheets is Pb _0.9625 Sm _0.025 [(Mg _1/3 Nb _2/3 ) _{1 -x} Ti _x ]O ₃ , abbreviated as 0.025Sm-PMN-xPT, 0.28≤x≤0.31; the piezoelectric ceramic sheet is used as the displacement element, and the stainless steel sheet is used as the lead-out electrode. The piezoelectric ceramic sheet and the stainless steel sheet pass through the ring Oxygen resin adhesive fixed.

Preferably, the piezoelectric ceramic sheet and the stainless steel sheet are both square; each stainless steel sheet has an outgoing end located on one side of the sheet, and the outgoing end is arc-shaped and has a small hole concentric with the arc.

More preferably, the size of the piezoelectric ceramic sheet is 5mm×5mm×1mm; the size of the stainless steel sheet is 5mm×5mm×0.05mm, the size of the lead-out end is 1mm wide, 2mm long and 0.05mm thick, and the lead end is round The arc radius is 0.5mm, and there is a small hole with a radius of 0.25mm concentric to the arc.

Preferably, the piezoelectric ceramic sheet is prepared by a two-step oxide solid-phase reaction method.

Preferably, the structure of the field-induced strain micro-displacement actuator further includes upper and lower cover plates, the upper and lower cover plates are electrodeless ceramic sheets, more preferably electrodeless square ceramic sheets; the electrodeless ceramic sheets are samarium-doped ceramic sheets Lead magnesium niobate-lead titanate ceramics.

Preferably, each piece of stainless steel metal sheet has a lead-out end as a lead-out electrode, the positive electrode of the stacked stainless steel metal sheet lead-out electrode is aligned in one column, the negative electrode is aligned in one column, or the positive and negative electrodes are aligned in the same column.

Preferably, the stainless steel sheet is 304 stainless steel sheet.

Preferably, the epoxy resin adhesive is a thermal curing one-component or two-component epoxy resin adhesive; more preferably Hysol E-214HP, Hysol EA 9466, Hysol EA 9340, Hysol 9464, At least one of A-1177-B, HF8015, 9461, 327 and 81120. The epoxy adhesive is suitable for heat curing one- and two-component epoxy adhesives for bonding stainless steel foil and ceramics, and has high peel strength, high impact strength and corrosion resistance when fully cured .

The preparation method of the above-mentioned field-induced strain micro-displacement actuator, comprising the following steps:

The electrodeless ceramic sheet is used as the lower cover, and the stainless steel metal sheet and the piezoelectric ceramic sheet are alternately stacked on it. After stacking to a set number of layers, the electrodeless ceramic sheet is used as the upper cover. The metal sheet and the piezoelectric ceramic sheet are fixed by epoxy resin adhesive. Each stainless steel metal sheet has a lead-out terminal as the lead-out electrode. pole, thereby obtaining a field-induced strain micro-displacement actuator.

Preferably, after the electrodeless ceramic sheet, the stainless steel metal sheet and the piezoelectric ceramic sheet are screen-printed with epoxy resin adhesive and stacked, they are cured at 25-200° C. for 6-24 hours.

Preferably, the method for preparing a field-induced strain micro-displacement actuator includes the following steps:

(1) A two-step oxide solid-phase reaction method is used to prepare a piezoelectric ceramic wafer, which is ground, polished, cut, and covered with silver electrodes to obtain a piezoelectric ceramic wafer; a chemical etching method is used to obtain a stainless steel metal wafer;

(2) Screen printing epoxy resin adhesive on both sides of piezoelectric ceramic sheet and stainless steel metal sheet;

(3) The electrodeless ceramic sheet is used as the lower cover, and the stainless steel sheet is placed on it, and then the electrode piezoelectric ceramic sheet is placed on the stainless steel sheet, and then the stainless steel sheet is placed in reverse, and stacked to the set number of layers in turn , and finally place a piece of electrodeless ceramic sheet as the upper cover plate, and the orientation of the positive terminal and the negative terminal of the stainless steel metal sheets stacked alternately and reversely are the same;

(4) Use stainless steel clamps to fix in the stacking direction and keep it vertical, and place it in an oven to cure at 25 to 200 ° C for 6 to 24 hours;

(5) Connect the positive electrodes of all stainless steel metal sheets with leads to serve as the positive electrodes of the actuators, and connect the negative electrodes of all stainless steel metal sheets with leads to serve as the negative electrodes of the actuators to obtain field-induced strain micro-displacement actuators.

Application of the above-mentioned field-induced strain micro-displacement actuator.

It is preferably used in the fields of micro-displacement tool holders, precision micro-displacement systems and precision positioning tables.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) The field-induced strain micro-displacement actuator of the present invention has large displacement output, small hysteresis, and good repeatability. Under optimal conditions, the actuator with a length of 26.24 mm can produce a displacement of 14.25 μm under a 1 kV driving electric field at room temperature, with a hysteresis of only 0.045‰.

(2) The displacement element and the lead-out electrode in the field-induced strain micro-displacement actuator of the present invention are fixed by epoxy resin adhesive, which solves the problem that the Ag electrode is difficult to achieve co-firing with the ceramic material in the prior art. It is composed of piezoelectric ceramic sheets as displacement elements and stainless steel metal sheets as lead electrodes alternately stacked. Under the same driving electric field, the strain increases linearly with the stacking length. The longer the stacking length, the greater the output displacement.

(3) The field-induced strain micro-displacement actuator of the present invention is expected to be used in the fields of micro-displacement tool rests, precision micro-displacement systems, and precision positioning workbenches.

Description of drawings

FIG. 1 is a schematic structural diagram of the field-induced strain micro-displacement actuator of the present invention.

FIG. 2 is a schematic diagram of the stacking process of the field-induced strain micro-displacement actuator of the present invention.

FIG. 3 is a displacement curve of an actuator with a length of 10.51 mm prepared in Example 1 under a unidirectional driving voltage of 1 kV.

FIG. 4 is the displacement curve of the actuator with a length of 17.88 mm prepared in Example 2 under a unidirectional driving voltage of 1 kV.

FIG. 5 is the displacement curve of the actuator with a length of 26.24 mm prepared in Example 3 under a unidirectional driving voltage of 1 kV.

Detailed ways

The present invention will be described in further detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

If the specific conditions are not indicated in the examples of the present invention, the conventional conditions or the conditions suggested by the manufacturer are used. The raw materials, reagents, etc., which are not specified by the manufacturer, are all conventional products that can be purchased from the market.

The square piezoelectric ceramic sheet material and the upper and lower cover plates of the present invention are samarium-doped lead magnesium niobate-lead titanate series ceramics, and the adhesive is an epoxy resin adhesive (Hysol E- 214HP is a kind of ointment type industrial grade epoxy resin adhesive. The adhesive is a one-component non-mixing adhesive, which is heated and polymerized to form a tough, strong structural adhesive with high peel strength and high impact strength. After fully cured, the product has excellent thermal shock resistance, mechanical properties and electrical insulation properties, and can be resistant to most chemicals and solvents), the square stainless steel sheet is made of 304 stainless steel.

The field-induced strain data in the present invention is obtained by testing a computer-controlled Keithley 2410 source meter and an MDS series LVDT micrometer.

The chemical formula of the samarium-doped lead magnesium niobate-lead titanate ceramic in the embodiment of the present invention is: Pb _0.9625 Sm _0.025 [(Mg _1/3 Nb _2/3 ) _0.72 Ti _0.28 ]O ₃ , which is simplified to 0.025Sm- PMN-0.28PT.

The preparation method of the ceramic comprises the following steps:

(1) The raw materials of Nb ₂ O ₅ and (MgCO ₃ ) ₄ ·Mg(OH) ₂ ·5H ₂ O were dried at 110° C. for 12 hours, and then aired to room temperature in a dry environment, and 13.516g was weighed with an electronic balance. (MgCO ₃ ) ₄ ·Mg(OH) ₂ ·5H ₂ O, 36.989g Nb ₂ O ₅ , ball-milled at 350r/min for 1.5h using a planetary ball mill for thorough mixing, wherein the mass ratio of zirconium balls: raw material: water In a ratio of 4:1:2, dry the ball-milled wet material, sieve out the powder with an 80-mesh sieve, put it in an alumina crucible, and move it to a muffle furnace at a temperature of 200 degrees Celsius/hour (°C/h) The heating rate was increased from room temperature to 1200 °C, and the temperature was kept for 6 h to obtain MgNb ₂ O ₆ precursor powder.

(2) Put the Sm ₂ O ₃ raw material into a muffle furnace for pre-sintering treatment, increase the temperature from room temperature to 500° C. at a heating rate of 200° C./h, and keep the temperature at 500° C. for 4 hours to obtain pretreated Sm ₂ O ₃ ; the precursor powders of Pb ₃ O ₄ , TiO ₂ , pretreated Sm ₂ O ₃ and MgNb ₂ O ₆ were kept at 110° C. for 12 h and dried in an electric heating constant temperature blast drying oven. Air to room temperature, weigh 69.005g Pb ₃ O ₄ , 1.362g Sm ₂ O ₃ , 6.985g TiO ₂ , 22.948g MgNb ₂ O ₆ with an electronic balance in turn, and then ball-mill at 350r/min for 1.5h to mix thoroughly. The mass ratio of ball:material:water is 2:1:1. Dry the ball-milled wet material, screen out the powder with an 80-mesh sieve, put it in an alumina crucible, and move it to a muffle furnace. The heating rate of °C/h was increased from room temperature to 900 °C, and the calcined powder was obtained after holding for 4 h.

(3) the pre-burned powder obtained in step (2) is ball-milled again, and the planetary ball mill is used for ball milling at a rotational speed of 350r/min for 1.5h to fully mix, wherein the mass ratio of zirconium ball: pre-burned powder: water is 2:1 : 1. Dry the ball-milled wet material, add a binder to the dry powder for granulation, the binder is a polyvinyl alcohol (PVA) solution with a mass fraction of 10%, and the addition amount is drying and pre-burning 10% of the mass of the powder, grind and mix, and pass through a 60-mesh sieve to obtain a fine powder with uniform particle size.

(4) Weigh 3g of the powder obtained by granulation, apply a pressure of 24MPa through a powder tablet machine, hold for 20s, and dry press to obtain a disc with a diameter of 25mm and a thickness of about 1.2mm. In order to ensure the scientific validity of the data, more Repeat this step several times to obtain no less than 10 wafers.

(5) Place the dry-pressed discs on an alumina ceramic plate in a stacked manner, and put them into a muffle furnace for degumming to obtain a green body. The degumming procedure is: start from room temperature, heat up to 120°C after 1h, hold at 120°C for 1h, then heat up to 250°C after 1h, hold at 250°C for 1h, then heat up to 450°C after 2h, and then heat up to 450°C after 2 hours. Incubate for 1 h, and finally raise the temperature to 750° C. for 1 h, keep at 750° C. for 0.5 h, and then cool down naturally.

(6) Put the green sheet into a crucible, seal it with zirconia powder, put it into a muffle furnace for sintering, and obtain a ceramic sheet. Sintering procedure: start from room temperature, heat up to 1250°C after 6h, keep at 1250°C for 2h, and then cool down naturally.

(7) Coating silver electrodes (19 mm in diameter) by screen printing technology, and placing them in a muffle furnace to burn silver to obtain a ceramic sheet with electrodes. Silver burning procedure: start from room temperature, heat up to 750°C after 4h, keep at 750°C for 15min, and then cool down naturally.

(8) With silicone oil as protection, a DC electric field is applied in the thickness direction of the ceramic sheet to perform polarization treatment. Polarization conditions: at room temperature, the polarization electric field intensity is 1kV/mm, and the polarization is 10min to obtain the final samarium-doped lead magnesium niobate-lead titanate ceramic.

Example 1

A field-induced strain micro-displacement actuator, as shown in Figure 1, is composed of square piezoelectric ceramic sheets as displacement elements and square stainless steel metal sheets as lead electrodes alternately stacked.

The preparation method of the field-induced strain micro-displacement actuator includes the following operation steps:

(1) Preparation of square piezoelectric ceramic sheet and cover plate: Pb _0.9625 Sm _0.025 [(Mg _1/3 Nb _2/3 ) _0.72 Ti _0.28 ]O ₃ (0.025Sm-PMN) with a diameter of about 22 mm and a thickness of about 1 mm -0.28PT) ceramic wafer, after grinding, polishing, cutting, and silver electrodes, a square ceramic wafer with a size of 5mm × 5mm × 1mm was obtained.

A 5mm×5mm×0.05mm square sheet of 304 stainless steel with a lead-out end was obtained by conventional chemical etching. The dimensions of the lead-out end were 1mm in width, 2mm in length and 0.05mm in thickness. The radius of the arc of the lead-out end was 0.5mm. A small hole with a radius of 0.25mm.

(2) Printing adhesive: square ceramic sheet and stainless steel sheet square surface screen printing epoxy resin adhesive.

(3) Stacking: Place an electrodeless square samarium-doped lead magnesium niobate-lead titanate ceramic sheet on the bottom layer as the lower cover, place a square stainless steel sheet on it, then place an electrode square ceramic sheet, and then reversely place the stainless steel sheet Metal sheets are stacked in sequence, and the number of square piezoelectric ceramic sheets with electrodes reaches 8. Finally, a square electrodeless samarium-doped lead magnesium niobate-lead titanate ceramic sheet is placed as the upper cover, and the stacked stainless steel metal sheets are alternately inverted. The orientation of the positive terminal of the sheet is the same, and the orientation of the negative terminal is the same, as shown in Figure 2.

(4) Curing: Use stainless steel clamps to fix the stack in the height direction and keep it vertical, and place it in an oven at 180° C. for 8 hours to cure.

(5) Welding leads: Pass the two leads through the small holes of the two rows of lead-out ends and solder them to connect, and finally lead out two leads.

The field-induced strain data is obtained by computer-controlled Keithley 2410 source meter and MDS series LVDT micrometer. Test conditions: the application period is 50s and the amplitude is 1kV unidirectional triangular wave voltage.

Test results: As can be seen from Figure 3, when the actuator length is 10.51mm, a displacement of 5.45μm is generated, the hysteresis is 0.45μm, and the converted strain is 0.043‰.

Example 2

The field-induced strain micro-displacement actuator was prepared according to the preparation method of Example 1, except that the stacking number of square ceramic sheets with electrodes in step (3) was changed to 15 pieces, and the rest of the preparation conditions and testing methods were the same as those of Example 1, A stack actuator of 5 mm × 5 mm × 17.88 mm was obtained.

Test results: As can be seen from Figure 4, when the actuator length is 17.88mm, a displacement of 10.26μm is generated, the hysteresis is 1μm, and the converted strain is 0.056‰.

Example 3

The field-induced strain micro-displacement actuator was prepared according to the preparation method of Example 1, except that the stacking number of square ceramic sheets with electrodes in step (3) was changed to 24 pieces, and the rest of the preparation conditions and testing methods were the same as those of Example 1, A stack actuator of 5 mm × 5 mm × 26.24 mm was obtained.

Test results: It can be seen from Figure 5 that when the actuator length is 26.24mm, a displacement of 14.25μm is generated, and the hysteresis is 1.17μm, which is converted into a strain of 0.045‰.

To sum up, the field-induced strain micro-displacement actuator prepared by using the material and preparation method provided by the present invention has large displacement output, small hysteresis, good repeatability, and can meet the requirements of large displacement and high-precision actuation. The strain requirements of the device are met, and the preparation method is simple and low in cost.

The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, The simplification should be equivalent replacement manners, which are all included in the protection scope of the present invention.

Claims (10)

1. A field-induced strain micro-displacement actuator is characterized by being formed by alternately stacking piezoelectric ceramic sheets and stainless steel metal sheets, wherein the chemical composition of the piezoelectric ceramic sheets is Pb_0.9625Sm_0.025[(Mg_1/3Nb_2/3)_1-xTi_x]O₃X is more than or equal to 0.28 and less than or equal to 0.31; the piezoelectric ceramic sheet is used as a displacement element, the stainless steel metal sheet is used as an extraction electrode, and the piezoelectric ceramic sheet and the stainless steel metal sheet are fixed through epoxy resin adhesive.

2. The field-induced strain micro-displacement actuator as claimed in claim 1, wherein each stainless steel foil has a lead-out terminal as a lead-out electrode, and the positive electrodes of the stacked stainless steel foil lead-out electrodes are aligned in a row, the negative electrodes are aligned in a row, or the positive and negative electrodes are aligned in the same row; the epoxy resin adhesive is a thermosetting single-component or double-component epoxy resin adhesive.

3. The actuator of claim 1, wherein the structure of the actuator further comprises upper and lower cover plates, the upper and lower cover plates are electrodeless ceramic plates, and the material of the upper and lower cover plates is samarium-doped lead magnesium niobate-lead titanate ceramic.

4. A field induced strain micro-displacement actuator according to claim 1, 2 or 3, wherein the piezoelectric ceramic sheet and the stainless steel metal sheet are both square; each stainless steel metal sheet is provided with a leading-out end positioned on one side of the sheet, and the leading-out end is arc-shaped and is provided with a small hole concentric with the arc; the epoxy resin adhesive is at least one of Hysol E-214HP, Hysol EA 9466, Hysol EA 9340, Hysol 9464, A-1177-B, HF 8015, 9461, 327 and 81120 of loctite.

5. The field induced strain micro-displacement actuator of claim 4, wherein the piezoelectric ceramic sheet has dimensions of 5mm x 1 mm; the stainless steel metal sheet has the size of 5mm multiplied by 0.05mm, the size of the leading-out end is 1mm in width, 2mm in length and 0.05mm in thickness, the radius of the circular arc of the leading-out end is 0.5mm, and a small hole with the radius of 0.25mm is concentrically arranged on the circular arc;

the stainless steel foil is 304 stainless steel foil.

6. A method for manufacturing a field induced strain micro-displacement actuator as claimed in any one of claims 1 to 5, comprising the steps of:

and taking the electrodeless ceramic sheet as a lower cover plate, sequentially and alternately stacking stainless steel metal sheets and piezoelectric ceramic sheets on the electrodeless ceramic sheet, taking the electrodeless ceramic sheet as an upper cover plate after stacking to a set number of layers, wherein the electrodeless ceramic sheet, the stainless steel metal sheets and the piezoelectric ceramic sheet are fixed by epoxy resin adhesive, each stainless steel metal sheet is provided with a leading-out end as a leading-out electrode, and all leading-out anodes and leading-out cathodes are respectively connected by leads to be used as the anode and the cathode of the actuator, so that the field induced strain micro-displacement actuator is obtained.

7. The method for manufacturing the field induced strain micro-displacement actuator according to claim 6, wherein the electrodeless ceramic sheet, the stainless steel metal sheet and the piezoelectric ceramic sheet are stacked by screen printing an epoxy resin adhesive, and then cured at 25-200 ℃ for 6-24 hours.

8. The method of claim 6, wherein the method comprises the steps of:

(1) preparing a piezoelectric ceramic wafer by adopting a two-step oxide solid-phase reaction method, and grinding, polishing, cutting and coating a silver electrode to obtain a piezoelectric ceramic sheet; obtaining a stainless steel metal sheet by a chemical etching method;

(2) screen printing epoxy resin adhesive on both surfaces of the piezoelectric ceramic sheet and the stainless steel metal sheet;

(3) taking the electrodeless ceramic sheet as a lower cover plate, placing a stainless steel metal sheet on the lower cover plate, then placing an electrode piezoelectric ceramic sheet on the stainless steel metal sheet, then reversely placing the stainless steel metal sheet, sequentially stacking the stainless steel metal sheet to a set number of layers, finally placing an electrodeless ceramic sheet as an upper cover plate, and alternately reversely rotating the positive leading-out ends of the stacked stainless steel metal sheets to be consistent in orientation and the negative leading-out ends to be consistent in orientation;

(4) fixing the glass fiber cloth along the stacking direction by using a stainless steel clamp, keeping the glass fiber cloth vertical, and curing the glass fiber cloth in an oven at 25-200 ℃ for 6-24 hours;

(5) all the positive electrodes of the stainless steel metal sheets were connected by a lead to be actuator positive electrodes, and all the negative electrodes of the stainless steel metal sheets were connected by a lead to be actuator negative electrodes, to obtain field-induced strain micro-displacement actuators.

9. Use of a field induced strain micro-displacement actuator as claimed in any one of claims 1 to 5.

10. Use of a field induced strain micro-displacement actuator according to claim 9, in the field of micro-displacement tool holders, precision micro-displacement systems and precision positioning stages.

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