Brazing process of piezoelectric ceramics, multilayer piezoelectric ceramic driver and preparation method thereof

Abstract

The present application relates to a kind of piezoelectric ceramic brazing process, multilayer piezoelectric ceramic driver and preparation method thereof, the piezoelectric ceramic front and back are provided with molecular silver paste layer printed by molecular silver paste, low-temperature brazing material is used on the surface of molecular silver paste layer with screen printing, after printing is completed, the piezoelectric ceramic sheet obtained by processing is sequentially stacked, a certain clamping force is applied, and after drying and softening, silver molecular silver paste layer and low-temperature brazing material are pre-alloyed.The multilayer piezoelectric ceramic driver prepared by the piezoelectric ceramic brazing process of the present application can avoid the use of adhesive, thereby preventing the failure of the driver in long-time working state.

Description

Technical fields:

[0001] This invention belongs to the field of piezoelectric device technology, specifically relating to a brazing process for piezoelectric ceramics, a multilayer piezoelectric ceramic actuator, and its preparation method. Background technology:

[0002] Piezoelectric ceramic materials possess both piezoelectric and inverse piezoelectric effects, enabling the interconversion of mechanical and electrical energy. Utilizing the inverse piezoelectric effect, piezoelectric actuators can be fabricated to achieve precise displacement control or powerful thrust output. In electronics, drive systems, and medical fields, piezoelectric actuators offer advantages such as extremely fast response speed, large output torque, and high linearity, leading to their widespread application. The output displacement and thrust of a piezoelectric actuator are directly proportional to the applied voltage (≤500V / mm); the higher the applied voltage, the greater the output displacement. However, there is a limitation to the applied voltage of single-layer piezoelectric actuators: less than 2000V per millimeter. Above 2000V, the output displacement exhibits a non-linear relationship with the voltage, and there is a risk of breakdown. By utilizing a stacked structure of single-layer piezoelectric ceramics and designing circuits to achieve a mechanical series and parallel circuit structure, more precise linear displacement repeatability and larger displacement magnitude can be achieved at lower operating voltages, thus forming multilayer piezoelectric ceramic actuators. By increasing the number of piezoelectric ceramic layers and reducing the thickness of a single layer, it is possible to achieve low-voltage, large-displacement driving with multilayer piezoelectric ceramic actuators.

[0003] Existing multilayer piezoelectric ceramic actuators are mainly manufactured using the following methods: 1) Integrating single-layer piezoelectric ceramic elements into multilayer piezoelectric ceramic actuators. Specifically, piezoelectric ceramics prepared by high-temperature sintering are processed into thin sheets with a thickness of 0.15–1.00 mm. After being top-electroded and polarized according to a certain structure and circuit design, these thin sheets are laminated and bonded together using an adhesive. 2) Using tape casting technology, piezoelectric ceramic green ceramic sheets are formed, and silver / palladium electrodes are printed as internal electrodes. The two are then co-fired at low temperature using a lamination method, i.e., LTCC (Low-Temperature Co-fired Ceramics) technology.

[0004] The existing technical solutions mentioned above have the following drawbacks: The multilayer piezoelectric ceramic actuators prepared by the first method are prone to thermal separation between the thin film and the adhesive when the working temperature is ≥100℃, because the adhesive used is generally a hot melt adhesive. This leads to a sharp decline in device performance or even failure, making it unsuitable for high-temperature working environments. Furthermore, the silver layers between the ceramic sheets need to be electrically conductive to each other, and it is difficult to achieve the micron-scale requirement for uniform thickness of the adhesive layer. The multilayer piezoelectric ceramic actuators prepared by the second method have low sintering temperature, resulting in low strength of the piezoelectric ceramic thin film itself. Although there is no high-temperature interlayer separation, its overall performance is not high, and the preparation requirements are high and the process is complex. Summary of the Invention:

[0005] The technical problem to be solved by the present invention is to provide a brazing process for piezoelectric ceramics, a multilayer piezoelectric ceramic actuator and its preparation method. By using the brazing process for piezoelectric ceramics to prepare a multilayer piezoelectric ceramic actuator, the use of adhesives can be avoided, thereby preventing the actuator from failing under long-term working conditions.

[0006] The technical solution of this invention is to provide a brazing process for piezoelectric ceramics. The piezoelectric ceramics have molecular silver paste layers printed on both sides. Low-temperature brazing material is screen-printed onto the surface of the molecular silver paste layers. After printing, the processed piezoelectric ceramic sheets are stacked sequentially and clamped with a special fixture under a certain force. After drying and softening, the silver molecular silver paste layers are pre-alloyed with the low-temperature brazing material. Finally, they are placed in a vacuum sintering furnace for sintering, integrating the multiple stacked piezoelectric ceramic sheets into a single unit.

[0007] The piezoelectric ceramic is a sheet-like piezoelectric ceramic of type P-5H or P-14;

[0008] The low-temperature brazing material is composed of the following components in weight percentage (total weight percentage 100%): 75%–85% metal alloy powder, 5%–10% flux powder, 10%–15% organic solvent, 0–2% thickener, and 0–2% dispersant; wherein the weight percentages of each component in the metal alloy powder are as follows: Sn: 30–60%, In: 30–70%, Pb: 10–30%, Cu: 0–10%, Ni: 0–10%.

[0009] The low-temperature brazing process involves applying a clamping force of 10–30 N and a drying temperature of 100–150 °C. The low-temperature brazing vacuum sintering conditions are: a vacuum degree of 10... -2 ~10 -5 Pa, temperature 300-500℃, holding time 1-10 minutes.

[0010] Preferably, the flux powder of the low-temperature brazing material is composed of potassium tetraaluminate fluoride and dimethyl pentafluoroaluminate.

[0011] Preferably, the organic solvent of the low-temperature brazing material is at least one of propylene glycol, butanediol, and ethylene glycol butyl ether.

[0012] Preferably, the thickener is polyethylene glycol and the dispersant is linoleic acid.

[0013] The present invention also provides a multilayer piezoelectric ceramic actuator prepared by brazing piezoelectric ceramics. The front and back surfaces of the piezoelectric ceramic sheets are respectively provided with molecular silver paste layers. Multiple piezoelectric ceramic sheets are stacked in sequence and fused together by low-temperature brazing material, and the molecular silver paste layers on the adjacent surfaces of adjacent piezoelectric ceramic sheets are interdigitated.

[0014] Specifically, electrodes are arranged opposite to each other on the left and right sides of the piezoelectric ceramic sheet;

[0015] The molecular silver paste layer on the side of the piezoelectric ceramic sheet closest to the left electrode is in contact with the edge of the piezoelectric ceramic sheet; the molecular silver paste layers on the other three sides of the piezoelectric ceramic sheet are 0.5 to 1.5 mm away from the outer edge of the piezoelectric ceramic sheet, thus forming an electrode blank area, and a glass glaze is printed on the electrode blank area to form a glass glaze layer.

[0016] The molecular silver paste layer on the back side of the piezoelectric ceramic sheet near the right electrode is in contact with the edge of the piezoelectric ceramic sheet; the molecular silver paste layers on the other three sides of the back side of the piezoelectric ceramic sheet are 0.5 to 1.5 mm away from the outer edge of the piezoelectric ceramic sheet, thus forming the electrode blank area. Glass glaze is printed on the electrode blank area and a glass glaze layer is formed.

[0017] The glass glaze is composed of an organic carrier and glass powder. Based on a total glass glaze content of 100%, the weight percentages of each component are as follows: glass powder 70%–85%; organic carrier 15%–30%. The organic carrier is an organic solvent and ethyl cellulose comprising 10–20% of the total organic solvent weight. The organic solvent is one or a combination of several of the following: butyl carbitol acetate, terpineol, dodecyl phthalate, dioctyl phthalate, and dimethyl phthalate.

[0018] The present invention also provides a method for fabricating a multilayer piezoelectric ceramic actuator, comprising the following steps:

[0019] Step 1: Piezoelectric ceramic sheet processing: The ceramic block is wire-cut and ground into square piezoelectric ceramic sheets of specific dimensions;

[0020] Step 2: Printing of the molecular silver paste layer of the piezoelectric ceramic sheet. Based on the internal structure of the multilayer piezoelectric actuator, design the corresponding screen pattern, use molecular silver paste and screen printing to print the molecular silver paste layer. After printing, dry at 100-250℃.

[0021] Step 3: Printing of the glass glaze layer of the piezoelectric ceramic sheet. The glass glaze is printed using screen printing. According to the internal structure of the multilayer piezoelectric actuator, the corresponding screen pattern is designed. After printing, it is dried at 150-350℃ to form the piezoelectric ceramic sheet element.

[0022] Step 4: Silver firing of piezoelectric ceramic elements, using a heat treatment temperature of 650-850℃ for 10-30 minutes;

[0023] Step 5: Polarization and cleaning of piezoelectric ceramic elements. The polarization voltage is 1.0~3.0kV / mm, the polarization temperature is 110~130℃, and the polarization time is 20-40 minutes. After polarization, use gasoline or silicone oil cleaner to clean the silicone oil off the surface of the element and let it air dry.

[0024] Step 6: Printing of the low-temperature solder layer of the piezoelectric ceramic element. Based on the internal structure of the multilayer piezoelectric actuator, design the corresponding screen pattern, and screen print it with low-temperature solder material. After printing, dry it at 80-120℃.

[0025] Step 7: Stacking and brazing of multilayer piezoelectric actuators. The piezoelectric ceramic elements are stacked according to the internal structure of the piezoelectric actuator, forming an interdigitated shape. A special clamping force is applied, and the layers are dried and softened at 100–150°C to pre-alloy the silver layer and solder. Finally, they are sintered in a vacuum furnace at a vacuum level of 10... -2 ~10 -5 Pa, temperature of 300~500℃, heat preservation time of 1~10 minutes, to realize the integration of multilayer piezoelectric actuator;

[0026] Step 8: Bonding of the side electrodes of the multilayer piezoelectric actuator. Apply epoxy resin or A / B glue to the electrode bonding area, then attach the copper electrode sheet, and cure at 80-120℃ for 10-30 minutes to obtain the side electrodes.

[0027] Furthermore, the piezoelectric ceramic sheet has the following specifications: a flat surface of 15mm × 15mm and a thickness of 0.5–1.0mm.

[0028] Furthermore, in step 2, the thickness of the molecular silver paste printing is 3.0–6.0 μm.

[0029] Furthermore, in step 3, the thickness of the glass glaze layer is 6.0–12.0 μm; in step 6, the thickness of the low-temperature brazing layer is 3.0–6.0 μm.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] Based on the structural characteristics of multilayer piezoelectric ceramic actuators, this invention develops a novel multilayer piezoelectric ceramic and its preparation method. The key feature is the use of brazing to achieve multilayer bonding of the piezoelectric ceramic, resulting in excellent electrical and mechanical properties. The multilayer piezoelectric actuator obtained using this preparation method exhibits large displacement and high torque, while also showing significantly improved mechanical strength compared to traditional bonding methods, thus meeting the requirements for applications at higher temperatures (≤200℃). Attached image description:

[0032] Figure 1 This is a schematic diagram of the structure of the present invention.

[0033] Figure 2 This is a schematic diagram showing the connection relationship between the piezoelectric ceramic sheet and the molecular silver paste layer of the present invention.

[0034] Figure 3 This is a schematic diagram showing the connection relationship between the piezoelectric ceramic sheet and the glass glaze layer of the present invention.

[0035] Figure 4 This is a schematic diagram showing the connection relationship between the piezoelectric ceramic element and the low-temperature brazing layer of the present invention.

[0036] Figure 5 This is a schematic diagram showing the connection relationship of the side electrodes of the multilayer piezoelectric ceramic actuator of the present invention.

[0037] Figure 6 This is a schematic diagram illustrating the displacement variation trend of the multilayer piezoelectric ceramic actuator under different voltages and loads according to an embodiment of the present invention. Detailed implementation method:

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0039] Example 1

[0040] Reference Figure 1 , 5 This invention discloses a multilayer piezoelectric ceramic actuator, comprising multiple stacked piezoelectric ceramic sheet elements 1 and series electrodes 3 disposed on these ceramic sheet elements 1. Each piezoelectric ceramic sheet element 1 includes a piezoelectric ceramic sheet, a molecular silver paste layer 2 printed on the piezoelectric ceramic sheet, a glass glaze layer 4, and a low-temperature solder layer 5. Furthermore, the multilayer piezoelectric ceramic actuator is square, with the piezoelectric ceramic sheet being a square thin sheet of 15mm × 15mm × 1.0mm, and the number of layers being 20.

[0041] Reference Figures 2-3To achieve the effect of parallel circuits with series electrodes, the multilayer piezoelectric ceramic actuator is square. Using a screen printing method, the electrode (molecular silver paste layer) prepared with molecular silver paste has its side closest to the left electrode as the full electrode, contacting the left edge of the piezoelectric ceramic sheet. The other three sides have molecular silver paste layer patterns with a 0.5-1.5mm margin on the piezoelectric ceramic sheet, forming electrode blank areas 21. The back molecular silver paste layer and the front molecular silver paste layer patterns are located on different sides of the same direction; in this embodiment, they are the left and right sides, respectively, to ensure that the electrodes on both sides are interdigitated when stacked into a multilayer piezoelectric actuator.

[0042] Step 1: Processing of piezoelectric ceramic sheets

[0043] We are purchasing a mature commercially available P-14 type piezoelectric ceramic material manufactured by Hangzhou AAC Technologies Co., Ltd., which has the following characteristics: T 33 =3400, d 33 It exhibits electrical properties of ≥650 pC / N and dielectric loss tan≤2.0%, and excellent electrostrain performance, with a strain coefficient of 0.085% per unit voltage (Strain=0.085%@1kV / mm). This means that a 1mm thick piezoelectric ceramic element exhibits a strain of 0.85μm at 1kV. The ceramic bulk is wire-cut and ground into piezoelectric ceramic sheets with dimensions of 15mm×15mm×1.0mm.

[0044] Step 2: Printing of piezoelectric ceramic sheet molecular silver paste electrodes

[0045] The piezoelectric ceramic sheet obtained in step 1 was screen-printed with molecular silver paste. A 350-mesh screen was selected for the pattern printing. To ensure that the fabricated multilayer piezoelectric actuator has a mechanical series and circuit parallel structure, corresponding electrode patterns were designed, such as... Figure 1 As shown, the molecular silver paste layer 2 is set as a full electrode on the side near the left electrode 3, that is, the molecular silver paste layer 2 is in contact with the left edge of the piezoelectric ceramic sheet; the molecular silver paste layer pattern on the right side leaves a 1.5mm margin with the piezoelectric ceramic sheet; in addition, the molecular silver paste layer patterns on the adjacent two sides leave a 1.0mm margin with the piezoelectric ceramic sheet. The preparation method is screen printing, and the thickness of the printed molecular silver paste is 3μm. After printing, it is dried at 150℃; after drying, the back molecular silver paste layer of the piezoelectric ceramic sheet is printed. The back molecular silver paste layer and the front molecular silver paste layer patterns are located on the left and right sides of the same direction, respectively, to ensure that the molecular silver paste layers on the front and back sides are interdigitated when stacked into a multilayer piezoelectric actuator.

[0046] Step 3: Printing of glass glaze and lamination of piezoelectric ceramic sheets

[0047] The piezoelectric ceramic sheet obtained in step 2 was also screen-printed using a 200-mesh screen. To ensure the fabricated multilayer piezoelectric actuator has a mechanically series and electrically parallel structure, a corresponding screen pattern was designed. The glass glaze was printed with an edge left on the silver layer of the piezoelectric ceramic sheet. The glass glaze printing area was precisely misaligned with the molecular silver paste layer printed in step 2, thus completely covering the piezoelectric ceramic sheet. Figure 3 As shown. The thickness of the printed glass glaze is 6μm. After printing, the piezoelectric ceramic sheet is dried at 150℃ to produce a piezoelectric ceramic element.

[0048] Step 4: Silvering of piezoelectric ceramic element

[0049] The piezoelectric ceramic element obtained in step 3 is kept at 750°C for 10 to 30 minutes to obtain a piezoelectric ceramic element with silver electrodes on both sides and glass glaze on the edges.

[0050] Step 5: Polarization and cleaning of piezoelectric ceramic elements

[0051] The polarization voltage of the piezoelectric ceramic element obtained in step 4 is determined according to the thickness of the sheet. The polarization voltage is 3.0 kV / element, the polarization temperature is 130℃, and the polarization time is 30 minutes. After polarization, the silicone oil on the surface of the element is cleaned with gasoline and then dried.

[0052] Step 6: Printing of the low-temperature solder layer for the piezoelectric ceramic element

[0053] Based on the internal structure of the multilayer piezoelectric actuator, a screen printing pattern is designed for the polarized piezoelectric ceramic element obtained in step 5. A 1mm margin is left between the printed low-temperature solder layer 5 area and the edge of the polarized piezoelectric ceramic element, as shown in the attached diagram. Figure 4 As shown. After printing, it is dried at 100℃;

[0054] Step 7: Stacking and Brazing of Multilayer Piezoelectric Actuators

[0055] The piezoelectric ceramic element with the printed low-temperature brazing layer obtained in step 6 is stacked according to the internal structure of the piezoelectric actuator, forming an interdigitated shape. A special clamping fixture is then applied with a certain clamping force, and the element is dried and softened at 150°C to pre-alloy the molecular silver paste layer and the low-temperature brazing layer. Finally, it is placed in a vacuum sintering furnace for sintering at a vacuum degree of 10. -3 Pa, temperature of 350℃, heat preservation time of 1 minute, realize the integration of multilayer piezoelectric actuator;

[0056] Step 8: Bonding of side electrodes of the multilayer piezoelectric actuator

[0057] The multilayer piezoelectric actuator obtained in step 7 is then... Figure 5Epoxy resin is applied to the position, and then copper electrode sheets are attached. The mixture is cured at 120°C for 10 minutes to obtain the effect of parallel circuits on the side electrodes.

[0058] Example 2 is a multilayer piezoelectric ceramic actuator disclosed in this invention. The difference from Example 1 is that the multilayer piezoelectric ceramic actuator is square and has 30 layers.

[0059] Example 3 is a multilayer piezoelectric ceramic actuator disclosed in this invention. The difference from Example 1 is that the multilayer piezoelectric ceramic actuator is square and has 40 layers.

[0060] Example 4 is a multilayer piezoelectric ceramic actuator disclosed in this invention. The difference from Example 3 is that the multilayer piezoelectric ceramic actuator is square, and the piezoelectric ceramic sheet is a square thin sheet of 15mm×15mm×0.5mm.

[0061] Example 5 is a multilayer piezoelectric ceramic actuator disclosed in this invention. The difference from Example 1 is that the multilayer piezoelectric ceramic actuator is square, and the piezoelectric ceramic sheet is a square thin sheet of 30mm×30mm×1.0mm. One side of the electrode is a full electrode that is in contact with the edge of the piezoelectric ceramic sheet. On the opposite side, the electrode pattern leaves a 3.0mm margin with the piezoelectric ceramic sheet. In addition, the electrode patterns on the adjacent two sides leave a 1.5mm margin with the piezoelectric ceramic sheet. The number of layers is 20.

[0062] Example 6 is a multilayer piezoelectric ceramic actuator disclosed in this invention. The difference from Example 1 is that the multilayer piezoelectric ceramic actuator is square, and the piezoelectric ceramic sheet is a square thin sheet of 30mm×30mm×1.0mm. One side of the electrode is a full electrode that is in contact with the edge of the piezoelectric ceramic sheet. On the opposite side, the electrode pattern leaves a 3.0mm margin with the piezoelectric ceramic sheet. In addition, the electrode patterns on the adjacent two sides leave a 1.5mm margin with the piezoelectric ceramic sheet. The number of layers is 40.

[0063] Example 7 is a multilayer piezoelectric ceramic actuator disclosed in this invention. The difference from Example 5 is that, after completion, the non-adhesive copper electrode sheet is cut by 1.5mm on each side. Thus, the single-layer piezoelectric ceramic element is a rectangular sheet of 27mm × 30mm × 1.0mm, with one electrode side being a full electrode in contact with the edge of the piezoelectric ceramic sheet; the electrode pattern on the opposite side has a 3.0mm margin with the piezoelectric ceramic sheet.

[0064] Performance testing

[0065] Table 1

[0066]

[0067] As can be seen from Examples 1-7 in Table 1, in this invention, the multilayer actuators prepared with the same single-layer piezoelectric ceramic sheet exhibit linear capacitance and displacement, which gradually increase with increasing stack thickness; among them, Example 3 achieves a displacement of 17.3 μm at a driving voltage of 500V. Additionally, as... Figure 6 This is a schematic diagram illustrating the displacement variation trend of the multilayer piezoelectric ceramic actuator under different voltages and loads according to an embodiment of the present invention.

[0068] This invention utilizes a brazing process to achieve multilayer bonding of piezoelectric ceramics, resulting in excellent electrical and mechanical properties. The multilayer piezoelectric actuator prepared using this method exhibits large displacement and high torque, while also showing significantly improved mechanical strength compared to traditional bonding methods, thus meeting the requirements for applications at higher temperatures (≤200℃).

[0069] The above description only illustrates preferred embodiments of the present invention and should not be construed as limiting the scope of the claims. Any equivalent procedural modifications made using this specification are included within the patent protection scope of this invention.

Claims

1. A brazing process for piezoelectric ceramics, characterized in that: The piezoelectric ceramic has a molecular silver paste layer printed on both sides. Low-temperature brazing material is then screen-printed onto the surface of the molecular silver paste layer. After printing, the processed piezoelectric ceramic sheets are stacked sequentially, clamped, and then dried and softened to pre-alloy the molecular silver paste layer with the low-temperature brazing material. Finally, they are placed in a vacuum sintering furnace for sintering, integrating the multiple stacked piezoelectric ceramic sheets into a single unit. The piezoelectric ceramic is a sheet-like piezoelectric ceramic of type P-5H or P-14; The low-temperature brazing material is composed of the following components in total weight percentage (100%): 75%~85% metal alloy powder, 5%~10% flux powder, 10%~15% organic solvent, 0~2% thickener, and 0~2% dispersant; wherein, the weight percentages of each component in the metal alloy powder are as follows: Sn: 30~60%, In: 30~70%, Pb: 10~30%, Cu: 0~10%, Ni: 0~10%. The clamping force is 10~30N, and the drying temperature is 100~150℃; the vacuum sintering conditions are: vacuum degree 10 -2 ~10 - 5 Pa, temperature 300~500℃, holding time 1~10 minutes.

2. The brazing process for piezoelectric ceramics according to claim 1, characterized in that: The flux powder of the low-temperature brazing material is composed of potassium tetraaluminate fluoride and dimethyl pentafluoroaluminate.

3. The brazing process for piezoelectric ceramics according to claim 1, characterized in that: The organic solvent for low-temperature brazing materials is at least one of propylene glycol, butanediol, and ethylene glycol butyl ether.

4. The brazing process for piezoelectric ceramics according to claim 1, characterized in that: The thickener is polyethylene glycol; the dispersant is linoleic acid.

5. A multilayer piezoelectric ceramic actuator fabricated using the brazing process of piezoelectric ceramics as described in any one of claims 1-4, characterized in that: The piezoelectric ceramic sheet has a molecular silver paste layer on its front and back surfaces respectively. Multiple piezoelectric ceramic sheets are stacked in sequence and fused together by low-temperature brazing material, and the molecular silver paste layer on the adjacent surfaces of adjacent piezoelectric ceramic sheets is interdigitated.

6. The multilayer piezoelectric ceramic actuator fabricated using the brazing process of piezoelectric ceramics according to claim 5, characterized in that: Electrodes are arranged opposite each other on the left and right sides of the piezoelectric ceramic sheet; The molecular silver paste layer on the front side of the piezoelectric ceramic sheet near the left electrode is in contact with the edge of the piezoelectric ceramic sheet; the molecular silver paste layers on the other three sides of the front side of the piezoelectric ceramic sheet are 0.5~1.5mm away from the outer edge of the piezoelectric ceramic sheet, thus forming an electrode blank area, and a glass glaze is printed on the electrode blank area to form a glass glaze layer. The molecular silver paste layer on the back side of the piezoelectric ceramic sheet near the right electrode is in contact with the edge of the piezoelectric ceramic sheet; the molecular silver paste layers on the other three sides of the back side of the piezoelectric ceramic sheet are 0.5~1.5mm away from the outer edge of the piezoelectric ceramic sheet, thus forming the electrode blank area. Glass glaze is printed on the electrode blank area and a glass glaze layer is formed. The glass glaze is composed of an organic carrier and glass powder. Based on the total amount of the glass glaze being 100%, the weight percentages of each component are as follows: glass powder 70%~85%; organic carrier 15%~30%.

7. A method for fabricating a multilayer piezoelectric ceramic actuator, characterized in that: Includes the following steps, Step 1: Piezoelectric ceramic sheet processing: The ceramic block is wire-cut and ground into square piezoelectric ceramic sheets; Step 2: Printing of the molecular silver paste layer of the piezoelectric ceramic sheet. Based on the internal structure of the multilayer piezoelectric actuator, design the corresponding screen pattern, use molecular silver paste and screen printing to print the molecular silver paste layer. After printing, dry at 100~250℃. Step 3: Printing of the glass glaze layer of the piezoelectric ceramic sheet. The glass glaze is printed using screen printing. According to the internal structure of the multilayer piezoelectric actuator, the corresponding screen pattern is designed. After printing, it is dried at 150~350℃ to form the piezoelectric ceramic sheet element. Step 4: Silver firing of piezoelectric ceramic elements, using a heat treatment temperature of 650~850℃ for 10~30 minutes; Step 5: Polarization and cleaning of piezoelectric ceramic elements. The polarization voltage is 1.0~3.0 kV / mm, the polarization temperature is 110~130℃, and the polarization time is 20-40 minutes. After polarization, use gasoline or silicone oil cleaner to clean the silicone oil off the surface of the element and let it air dry. Step 6: Printing of the low-temperature solder layer of the piezoelectric ceramic element. Based on the internal structure of the multilayer piezoelectric actuator, design the corresponding screen pattern, and screen print it with low-temperature solder material. After printing, dry it at 80~120℃. Step 7: Stacking and brazing of multilayer piezoelectric actuators. The piezoelectric ceramic elements are stacked according to the internal structure of the piezoelectric actuator, forming an interdigitated shape. Clamping force is applied, and the mixture is dried and softened at 100-150℃ to pre-alloy the silver layer and solder. Finally, it is placed in a vacuum sintering furnace for sintering at a vacuum degree of 10... -2 ~10 -5 Pa, temperature of 300~500℃, heat preservation time of 1~10 minutes, to realize the integration of multilayer piezoelectric actuator; Step 8: Bonding of the side electrodes of the multilayer piezoelectric actuator. Apply epoxy resin or A / B glue to the electrode bonding area, then attach the copper electrode sheet, and cure at 80~120℃ for 10~30 minutes to obtain the side electrodes.

8. The method for fabricating a multilayer piezoelectric ceramic actuator according to claim 7, characterized in that: The piezoelectric ceramic sheet has the following specifications: a flat surface of 15mm × 15mm and a thickness of 0.5~1.0mm.

9. The method for preparing the multilayer piezoelectric ceramic actuator according to claim 7, characterized in that: In step 2, the thickness of the molecular silver paste printing is 3.0~6.0μm.

10. The method for fabricating a multilayer piezoelectric ceramic actuator according to claim 7, characterized in that: In step 3, the thickness of the glass glaze layer is 6.0~12.0μm; in step 6, the thickness of the low-temperature brazing layer is 3.0~6.0μm.

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