A multi-layer piezoelectric ceramic actuator and its preparation method

Abstract

The present invention relates to a multi-layer piezoelectric ceramic actuator and a preparation method thereof. A multi-layer piezoelectric ceramic actuator includes a plurality of stacked piezoelectric ceramic wafers, a molecular silver paste layer printed on both side surfaces of the piezoelectric ceramic wafers, and a glass glaze layer disposed between adjacent two molecular silver paste layers; wherein, the chemical stoichiometric general formula of the piezoelectric ceramic wafer formulation is Pb 1‑m‑ n Sr m Ba n [(Mg 1 / 3 Nb 2 / 3 ) x (Ni 1 / 3 Nb 2 / 3 ) y (Zr z Ti 1‑z ) 1‑x‑y O3+ a mol%Sm2O3+ b mol%Nb2O5; The preparation method includes steps of preparing piezoelectric ceramic wafers, screen-printing molecular silver paste layers and glass glaze layers, laminating, installing alumina ceramic sheets, and polarizing. The preparation method of the multi-layer piezoelectric ceramic actuator of the present invention utilizes a glass phase with low-temperature sintering, and the preparation of the multi-layer piezoelectric ceramic actuator can be realized at a lower temperature. The multi-layer piezoelectric ceramic actuator obtained by adopting this preparation method has the characteristics of large displacement and large torque. At the same time, the mechanical strength is also greatly improved compared with the traditional bonding preparation method, and it can also meet its application at a higher temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of piezoelectric devices, and in particular to a multi-layer piezoelectric ceramic actuator and a preparation method thereof. Background Art

[0002] Piezoelectric ceramic materials are information functional ceramic materials that can convert mechanical energy and electrical energy into each other. Piezoelectric actuators utilize the inverse piezoelectric effect of piezoelectric ceramic materials to convert electrical energy into mechanical deformation to achieve displacement control or output thrust. Due to the advantages of fast response speed, large output torque, high linearity, etc. of piezoelectric actuators, they have been widely used in the fields of electronics, drive, medical treatment, etc. With the rapid development of microelectronic technology and the further improvement of product performance, single-layer piezoelectric actuators can no longer meet the usage requirements of current related applications, and multi-layer piezoelectric ceramic actuators have emerged as the times require. The multi-layer piezoelectric ceramic actuator utilizes a piezoelectric ceramic sheet stack structure and, through circuit design, realizes a structure of mechanical series connection and circuit parallel connection, and can have more precise linear displacement repeatability and larger displacement at a lower operating voltage.

[0003] The multi-layer piezoelectric ceramic actuator can achieve the purpose of low-voltage and large-displacement drive by increasing the number of piezoelectric ceramic layer stacks and reducing the thickness of a single layer. The existing multi-layer piezoelectric ceramic actuators are mainly manufactured by the following methods: 1) cutting the piezoelectric ceramic material obtained by high-temperature sintering into thin sheets with a thickness of 0.15 - 1.00 mm, after applying upper electrodes and polarization, processing and laminating and bonding these thin sheets with an adhesive; 2) co-firing with silver / palladium electrodes and piezoelectric ceramic thin sheets at a low temperature.

[0004] The above-mentioned existing technical solutions have the following defects: for the multi-layer piezoelectric ceramic actuator manufactured by the first method, when the operating temperature ≥ 100 °C, since the adhesive used is generally a hot-melt adhesive, it is easy to be thermally separated between the thin sheet and the adhesive, resulting in a sharp decline in device performance or even failure, and it is not suitable for high-temperature working environments; for the multi-layer piezoelectric ceramic actuator manufactured by the second method, due to the low sintering temperature, the strength of the piezoelectric ceramic thin sheet itself is not high. Although there is no high-temperature interlayer separation, its comprehensive performance is not high, and the preparation requirements are high and the process is complex.

[0005] Therefore, exploring a new type of multi-layer piezoelectric ceramic actuator and its preparation method to combine the advantages of these two existing methods, that is, to realize high-temperature bonding of ceramic thin sheet components prepared by high-temperature sintering, so as to meet its application at a higher temperature on the premise that the electrical and mechanical properties of the piezoelectric ceramic do not decline, is a problem that needs to be solved urgently at present. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the first object of the present invention is to provide a multi-layer piezoelectric ceramic actuator, which achieves the purpose of maintaining excellent electrical and mechanical properties at higher temperatures by setting a molecular silver paste layer and a glass glaze layer between piezoelectric ceramic sheets and optimizing the molecular structure of the piezoelectric ceramic sheets.

[0007] The second object of the present invention is to provide a preparation method of a multi-layer piezoelectric ceramic actuator, which can realize the preparation of a multi-layer piezoelectric ceramic actuator at a lower temperature by using a glass phase with low-temperature sintering. The multi-layer piezoelectric ceramic actuator obtained by using this preparation method has the characteristics of large displacement and large torque, and at the same time, its mechanical strength is greatly improved compared with the traditional bonding preparation method, and it can also meet its application at higher temperatures.

[0008] To achieve the above first object, the present invention provides the following technical solutions:

[0009] A multi-layer piezoelectric ceramic actuator includes a plurality of stacked piezoelectric ceramic wafers, a molecular silver paste layer printed on both side surfaces of the piezoelectric ceramic wafers, and a glass glaze layer disposed between adjacent two molecular silver paste layers; wherein, the chemical stoichiometric general formula of the piezoelectric ceramic wafer is Pb 1-m-n Sr m Ba n [(Mg 1 / 3 Nb 2 / 3 ) x (Ni 1 / 3 Nb 2 / 3 ) y (Zr z Ti 1-z ) 1-x-y O3+ a mol%Sm2O3+ b mol%Nb2O5, x = 0.15~0.25, y = 0~0.05, z = 0.45~0.55, m = 0.02~0.10, n = 0~0.05, a = 0~1.20, b = 0~0.40.

[0010] Further, the chemical stoichiometric general formula of the piezoelectric ceramic wafer is Pb 0.90 Sr 0.09 Ba 0.01 [(Mg 1 / 3Nb 2 / 3 ) 0.25 (Zr 0.495 Ti 0.505 ) 0.75 O3+0.5mol%Sm2O3+0.1mol%Nb2O5.

[0011] Further, the molecular silver paste layer is composed of raw materials containing the following weight percentages: 85 - 90% of molecular silver powder, 0.5 - 5.0% of glass powder, and 5 - 30% of organic carrier.

[0012] Furthermore, the printing thickness of the molecular silver paste layer is 1 - 3 μm, and a blank margin of 0.5 - 2.0 mm is reserved between the molecular silver paste layer and the piezoelectric ceramic wafer.

[0013] Most further, the multi-layer piezoelectric ceramic actuator is set to be square, the side of the molecular silver paste layer protrudes and extends to form electrode pins, and the projections of the electrode pins on both sides of the piezoelectric ceramic wafer in the thickness direction do not overlap and are on the same side of the molecular silver paste layer.

[0014] Alternatively, the multi-layer piezoelectric ceramic actuator is set to be circular, the side of the molecular silver paste layer protrudes and extends to form electrode pins, and the projections of the electrode pins on both sides of the piezoelectric ceramic wafer in the thickness direction do not overlap and are on the opposite sides of the molecular silver paste layer.

[0015] Preferably, in the molecular silver paste layer, the molecular silver powder is spherical silver powder with a particle size of 0.5 - 2.0 μm, and the particle size distribution is a normal distribution, D 50 = 1 μm.

[0016] Preferably, in the molecular silver paste layer, the glass powder is a Bi-based Bi - B - Pb - Al - Ti glass system mainly composed of Bi2O3, and it is composed of the following raw materials in weight percentages: 60 - 70% of Bi2O3, 10 - 20% of B2O3, 10 - 20% of PbO, 0 - 5% of Al2O3, and 0 - 5% of TiO2.

[0017] Preferably, in the molecular silver paste layer, the organic carrier is an organic solvent and ethyl cellulose accounting for 10 - 20% of the total weight of the organic solvent, and the organic solvent is a composition of one or more of butyl carbitol acetate, terpineol, alcohol ester 12, dioctyl phthalate, and dimethyl phthalate.

[0018] Further, the glass glaze layer is composed of raw materials containing the following weight percentages: 70 - 85% of glass powder; 5 - 30% of organic carrier.

[0019] Furthermore, the printing thickness of the glass glaze layer is 1 - 3 μm, and a blank margin of 0.1 - 0.3 mm is reserved between the glass glaze layer and the piezoelectric ceramic wafer.

[0020] Most further, the side of the glass glaze layer is recessed inward to form two pin slots, and the projections of this pair of pin slots and the electrode pins on both sides of the glass glaze layer in the thickness direction overlap.

[0021] Preferably, in the glass glaze layer, the glass micro-powder is a Bi-based Bi-B-Pb-Al-Ti glass system mainly composed of Bi2O3, which is composed of raw materials in the following weight percentages: Bi2O3 60-70%, B2O3 10-20%, PbO 10-20%, Al2O3 0-5%, TiO2 0-5%.

[0022] Preferably, in the glass glaze layer, the organic carrier is an organic solvent and ethyl cellulose accounting for 10-20% of the total weight of the organic solvent, and the organic solvent is a composition of one or more of butyl carbitol acetate, terpineol, alcohol ester 12, dioctyl phthalate, and dimethyl phthalate.

[0023] To achieve the above second object, the present invention provides the following technical solutions:

[0024] A preparation method of a multi-layer piezoelectric ceramic actuator includes the following steps:

[0025] S1 Weigh the raw materials Pb3O4, ZrO2, TiO2, Nb2O5, Ni2O3, MgO, Sm2O3, SrCO3, BaCO3 according to the chemical stoichiometric formula, and then successively carry out first ball milling, drying and calcination, second ball milling and plasticizing treatment, and form a ceramic blank. Then successively carry out high-temperature degassing and high-temperature sintering to obtain a ceramic block, and then successively carry out wire cutting and grinding to obtain a piezoelectric ceramic thin sheet;

[0026] S2 Screen-print a molecular silver paste layer on both side surfaces of the piezoelectric ceramic thin sheet in sequence, and after each printing is completed, carry out drying treatment to obtain a first-layer piezoelectric ceramic sheet, and then screen-print a glass glaze layer on the lower side surface of the first-layer piezoelectric ceramic sheet to obtain a second-layer piezoelectric ceramic sheet;

[0027] S3 Stack the first-layer piezoelectric ceramic sheet and multiple second-layer piezoelectric ceramic sheets from bottom to top according to the predetermined number of layers, dry them under the state of clamping and pressing, and then print series electrodes on the sides of the first-layer piezoelectric ceramic sheet and these second-layer piezoelectric ceramic sheets to obtain a laminated body;

[0028] S4 Place a high-density ceramic plate on the upper side surface of the laminated body, heat it at high temperature and then cool it naturally to solidify to obtain a semi-finished piezoelectric actuator;

[0029] S5 Carry out polarization treatment on the semi-finished piezoelectric actuator to obtain a multi-layer piezoelectric ceramic actuator.

[0030] Further, in the step S1, the first ball milling time is 2 - 10 h, the calcination temperature is 800 - 860 °C, the calcination time is 1.5 - 2.5 h, and the second ball milling time is 4 - 16 h; the temperature for high-temperature degassing is 680 - 720 °C, and the temperature for high-temperature sintering is 1280 - 1320 °C, and the time is 1.5 - 4 h.

[0031] Furthermore, in the step S1, the ball milling media for the first ball milling and the second ball milling are zirconium balls, and the weight ratio of the piezoelectric ceramic sheet raw material, zirconium balls, and water is 1.0:(1.8 - 2.2):(0.6 - 1.0), preferably 1.0:2.0:0.75.

[0032] Further, in the step S2, the mesh number of the screen printing is 200 - 500 meshes; after each screen printing of the molecular silver paste layer, it is dried at 100 - 250 °C.

[0033] Further, in the step S2, the mesh number of the screen printing is 200 - 500 meshes; after each screen printing of the molecular silver paste layer, it is dried at 100 - 250 °C.

[0034] Further, in the step S3, the clamping pressure is 10 - 30 N, and the drying temperature is 150 - 350 °C; the series electrodes are printed on the side edges of the first layer of piezoelectric ceramic sheets and these second layer of piezoelectric ceramic sheets along the lead-out positions of the electrode pins and form a series circuit.

[0035] Further, in the step S4, the high-temperature heating temperature is 700 - 800 °C, and the time is 20 - 40 min.

[0036] Further, in the step S5, the polarization voltage is determined according to the thickness of the single-layer piezoelectric ceramic sheet and is 2.0 - 3.0 kV / mm; the polarization temperature is 110 - 130 °C, and the time is 10 - 30 min.

[0037] In summary, the beneficial technical effects of the present invention are as follows:

[0038] 1. The multi-layer piezoelectric ceramic actuator of the present invention has excellent electrical properties with ε T 33 ≥6000, d 33 ≥850 pC / N, dielectric loss tanδ ≤ 1.5%, and electrostrictive strain ≥ 0.095% under an electric field of 1 kV / mm, and also has a high density with ρ ≥ 7.90 g / cm 3 , achieving the purpose of maintaining excellent electrical and mechanical properties at a relatively high temperature;

[0039] 2. The method of the present invention utilizes a glass phase sintered at low temperature, enabling the preparation of a multi-layer piezoelectric ceramic actuator at a relatively low temperature. The multi-layer piezoelectric ceramic actuator obtained by this preparation method features large displacement and large torque. At the same time, its mechanical strength is significantly improved compared with the traditional bonding preparation method, and it can also meet its application at a relatively high temperature (200 °C). Description of the Drawings

[0040] Figure 1 It is a schematic structural diagram of the multi-layer piezoelectric ceramic actuator of Embodiment 1 of the present invention.

[0041] Figure 2 It is a schematic diagram of the connection relationship between the piezoelectric ceramic thin sheet and the molecular silver paste layer of Embodiment 1 of the present invention.

[0042] Figure 3 It is a schematic diagram of the connection relationship between the piezoelectric ceramic thin sheet and the glass glaze layer of Embodiment 1 of the present invention.

[0043] Figure 4 It is a schematic structural diagram of the multi-layer piezoelectric ceramic actuator of Embodiment 6 of the present invention.

[0044] Figure 5 It is a schematic diagram of the connection relationship between the piezoelectric ceramic thin sheet and the molecular silver paste layer of Embodiment 6 of the present invention.

[0045] Figure 6 It is a schematic diagram of the connection relationship between the piezoelectric ceramic thin sheet and the glass glaze layer of Embodiment 6 of the present invention.

[0046] Figure 7 It is the displacement change trend of the multi-layer piezoelectric ceramic actuator of Embodiment 1 of the present invention under different voltages and loads. Detailed Embodiments

[0047] In order to make the technical means, creative features, achieved purposes and functions of the present invention clearer and easier to understand, the present invention will be further described below in conjunction with the drawings and specific embodiments. Embodiment

[0048] Embodiment 1: Refer to Figures 1 - 3 , a multi-layer piezoelectric ceramic actuator disclosed in the present invention, which includes a first-layer piezoelectric ceramic sheet, a plurality of second-layer piezoelectric ceramic sheets and a high-density ceramic plate stacked in sequence from bottom to top, and series electrodes provided on the first-layer piezoelectric ceramic sheet and these second-layer piezoelectric ceramic sheets. Among them, the first-layer piezoelectric ceramic sheet includes a piezoelectric ceramic thin sheet and molecular silver paste layers printed on both side surfaces of the piezoelectric ceramic thin sheet. The second-layer piezoelectric ceramic sheet includes the first-layer piezoelectric ceramic sheet and a glass glaze layer printed on the lower side surface of the first-layer piezoelectric ceramic sheet. The high-density ceramic plate is set as an alumina ceramic thin sheet.

[0049] To achieve the effect of parallel circuits for the series electrodes, the multi-layer piezoelectric ceramic actuator is set to be square. The piezoelectric ceramic thin sheets are square sheets with dimensions of 30 mm × 30 mm × 0.5 mm, and the number of stacked layers is 20. There is a blank margin reserved between the molecular silver paste layer and the piezoelectric ceramic thin sheets. The side edges of the molecular silver paste layer protrude and extend to form electrode pins, and the projections of the electrode pins on both sides of the piezoelectric ceramic thin sheets in the thickness direction do not overlap and are located on the same side of the molecular silver paste layer. In addition, there is also a blank margin reserved between the glass glaze layer and the piezoelectric ceramic thin sheets. The side edges of the glass glaze layer are recessed inward to form two pin slots, and the projections of these two pin slots and the electrode pins on both sides of the glass glaze layer in the thickness direction overlap. The series electrodes are printed on the side edges of these second-layer piezoelectric ceramic sheets along the lead-out positions of the electrode pins to form a series circuit.

[0050] The present invention also correspondingly discloses a preparation method for a multi-layer piezoelectric ceramic actuator, including the following steps.

[0051] S1 Weigh the raw materials Pb3O4, ZrO2, TiO2, Nb2O5, Ni2O3, MgO, Sm2O3, SrCO3, BaCO3 according to the chemical stoichiometric formula Pb 0.90 Sr 0.09 Ba 0.01 [(Mg 1 / 3 Nb 2 / 3 ) 0.25 (Zr 0.495 Ti 0.505 ) 0.75 O3 + 0.50 mol% Sm2O3 + 0.1 mol% Nb2O5. After weighing, first ball-mill and mix for 4 h, dry and then calcine at 860 °C for 2.0 h, and then ball-mill for 6 h for the second time. The obtained fine powder is subjected to plasticizing treatment and then formed into a ceramic blank. Among them, the ball-milling media for the first ball-milling and the second ball-milling are zirconium balls, and the weight ratio of the piezoelectric ceramic thin sheet raw material, zirconium balls and water is 1.0:2.0:0.75. Then, successively pass through high-temperature degassing at 700 °C and high-temperature sintering at 1300 °C for 2.0 h to obtain a ceramic block. Then, successively pass through wire cutting and grinding to obtain piezoelectric ceramic thin sheets, and obtain the first-layer piezoelectric ceramic sheets.

[0052] S2 First, weigh the raw materials according to 88% molecular silver powder, 3% glass powder, and 9% organic carrier to obtain molecular silver paste. Then, screen-print the molecular silver paste on the two side surfaces of the piezoelectric ceramic thin sheets in sequence. The mesh number of the screen printing is 400 meshes, and the printing thickness of the molecular silver paste is 5 μm. After each printing is completed, it is dried at 200 °C to obtain a molecular silver paste layer with a 2.0 mm blank margin reserved between it and the piezoelectric ceramic thin sheets and with electrode pins.

[0053] First, weigh the raw materials according to 85% glass powder and 15% organic carrier to obtain the glass glaze. Then, screen-print the glass glaze on the surface of one of the molecular silver paste layers. The mesh number of the screen printing is 400 meshes, and the printing thickness of the glass glaze layer is 2 μm, so as to obtain a glass glaze layer with a blank margin of 0.2 mm reserved between it and the piezoelectric ceramic wafer and with pin slots, and further obtain the second piezoelectric ceramic wafer.

[0054] Among them, the molecular silver powder is spherical silver powder with a particle size of 0.5 - 2.0 μm, and the particle size distribution is in a normal distribution. D 50 = 1 μm. The glass micropowder is composed of raw materials with the following weight percentages: 65% Bi2O3, 15% B2O3, 15% PbO, 2% Al2O3, and 3% TiO2; the organic carrier is butyl carbitol acetate and ethyl cellulose accounting for 15% of the total weight of butyl carbitol acetate.

[0055] S3 Stack the first piezoelectric ceramic wafer and multiple second piezoelectric ceramic wafers layer by layer from bottom to top according to the predetermined number of layers, clamp and apply pressure, and after drying under pressure at 20 N and 200 °C, print series electrodes on the sides of these second piezoelectric ceramic wafers along the lead-out position of the electrode pins to obtain a laminated body.

[0056] S4 Place a high-density ceramic plate with the same area as the piezoelectric ceramic wafer on the upper surface of the laminated body, heat it at 780 °C for 30 min and then cool it naturally to solidify, obtaining a semi-finished piezoelectric actuator.

[0057] S5 Perform polarization treatment on the semi-finished piezoelectric actuator. The polarization voltage is 1.2 kV, the temperature is 110 °C, and the time is 30 min to obtain a multi-layer piezoelectric ceramic actuator.

[0058] Embodiment 2: A multi-layer piezoelectric ceramic actuator disclosed in the present invention, which is different from Embodiment 1 in that it includes a first piezoelectric ceramic wafer, multiple second piezoelectric ceramic wafers, a high-density ceramic plate stacked layer by layer from bottom to top in sequence, and series electrodes provided on the first piezoelectric ceramic wafer and these second piezoelectric ceramic wafers. Among them, the first piezoelectric ceramic wafer includes a piezoelectric ceramic wafer and molecular silver paste layers printed on both side surfaces of the piezoelectric ceramic wafer. The second piezoelectric ceramic wafer includes the first piezoelectric ceramic wafer and a glass glaze layer printed on the lower side surface of the first piezoelectric ceramic wafer. The high-density ceramic plate is set as an alumina ceramic wafer.

[0059] To achieve the effect of parallel circuits for the series electrodes, the multi-layer piezoelectric ceramic actuator is set to be square. The piezoelectric ceramic thin sheets are square sheets with dimensions of 30mm×30mm×0.5mm, and the number of stacked layers is 50. A blank margin is reserved between the molecular silver paste layer and the piezoelectric ceramic thin sheets. The side edges of the molecular silver paste layer protrude and extend to form electrode pins, and the projections of the electrode pins on both sides of the piezoelectric ceramic thin sheets in the thickness direction do not overlap and are located on the same side of the molecular silver paste layer. In addition, a blank margin is also reserved between the glass glaze layer and the piezoelectric ceramic thin sheets. The side edges of the glass glaze layer are recessed inward to form two pin slots, and the projections of these two pin slots and the electrode pins on both sides of the glass glaze layer in the thickness direction overlap. The series electrodes are printed on the side edges of these second-layer piezoelectric ceramic sheets along the lead-out positions of the electrode pins to form a series circuit.

[0060] The present invention also correspondingly discloses a preparation method for a multi-layer piezoelectric ceramic actuator, including the following steps.

[0061] S1 Weigh the raw materials Pb3O4, ZrO2, TiO2, Nb2O5, Ni2O3, MgO, Sm2O3, SrCO3, BaCO3 according to the chemical stoichiometric formula Pb 0.90 Sr 0.09 Ba 0.01 [(Mg 1 / 3 Nb 2 / 3 ) 0.25 (Zr 0.495 Ti 0.505 ) 0.75 )O3 + 0.50 mol% Sm2O3 + 0.1 mol% Nb2O5. After weighing, first ball-mill and mix for 2 h, dry and then calcine at 830 °C for 1.5 h, and then ball-mill for 10 h for the second time. The obtained fine powder is subjected to plasticizing treatment and then formed into a ceramic blank. Among them, the ball-milling media for the first ball-milling and the second ball-milling are zirconium balls, and the weight ratio of the piezoelectric ceramic thin sheet raw material, zirconium balls and water is 1.0:1.8:1.0. Then, successively pass through high-temperature degreasing at 680 °C and high-temperature sintering at 1280 °C for 1.5 h to obtain a ceramic block. Then, successively pass through wire cutting and grinding to obtain piezoelectric ceramic thin sheets, and obtain the first-layer piezoelectric ceramic sheets.

[0062] S2 First, weigh the raw materials according to 85% molecular silver powder, 0.5% glass powder, and 14.5% organic carrier to obtain molecular silver paste. Then, screen-print the molecular silver paste on the two side surfaces of the piezoelectric ceramic thin sheets in turn. The mesh number of the screen printing is 200 meshes, and the printing thickness of the molecular silver paste is 4 μm. After each printing is completed, it is dried at 100 °C to obtain a molecular silver paste layer with a 0.5 mm blank margin reserved between it and the piezoelectric ceramic thin sheets and with electrode pins.

[0063] First, weigh the raw materials according to 70% glass powder and 30% organic carrier to obtain glass glaze. Then, screen-print the glass glaze on the surface of one of the molecular silver paste layers. The mesh number of the screen printing is 200 mesh, and the printing thickness of the glass glaze layer is 2 μm, obtaining a glass glaze layer with a 0.1 mm blank margin reserved between it and the piezoelectric ceramic wafer and with pin slots, thereby obtaining the second piezoelectric ceramic wafer.

[0064] Among them, the molecular silver powder is spherical silver powder with a particle size of 0.5 - 2.0 μm, and the particle size distribution is normally distributed. D 50 = 1 μm. The glass micropowder is composed of raw materials with the following weight percentages: Bi2O3 60%, B2O3 10%, PbO 20%, Al2O3 5%, TiO2 5%. The organic carrier is terpineol and ethyl cellulose accounting for 10% of the total weight of terpineol.

[0065] S3 Stack the first piezoelectric ceramic wafer and multiple second piezoelectric ceramic wafers layer by layer from bottom to top according to the predetermined number of layers, clamp and apply pressure, and after drying under pressure at 10 N and 150 °C, print series electrodes on the sides of these second piezoelectric ceramic wafers along the lead-out positions of the electrode pins to obtain a laminated body.

[0066] S4 Place a high-density ceramic plate with the same area as the piezoelectric ceramic wafer on the upper surface of the laminated body, heat it at 750 °C for 20 min and then cool it naturally to solidify, obtaining a semi-finished piezoelectric actuator.

[0067] S5 Perform polarization treatment on the semi-finished piezoelectric actuator. The polarization voltage is 1.0 kV, the temperature is 120 °C, and the time is 15 min to obtain a multi-layer piezoelectric ceramic actuator.

[0068] Embodiment 3: A multi-layer piezoelectric ceramic actuator disclosed in the present invention, which is different from Embodiment 1 in that it includes a first piezoelectric ceramic wafer, multiple second piezoelectric ceramic wafers, a high-density ceramic plate, and series electrodes provided on the first piezoelectric ceramic wafer and these second piezoelectric ceramic wafers, which are stacked in sequence from bottom to top. Among them, the first piezoelectric ceramic wafer includes a piezoelectric ceramic wafer and molecular silver paste layers printed on both side surfaces of the piezoelectric ceramic wafer. The second piezoelectric ceramic wafer includes the first piezoelectric ceramic wafer and a glass glaze layer printed on the lower side surface of the first piezoelectric ceramic wafer. The high-density ceramic plate is set as an alumina ceramic wafer.

[0069] To achieve the effect of parallel circuits for the series electrodes, the multi-layer piezoelectric ceramic actuator is set to be square. The piezoelectric ceramic flakes are square flakes with dimensions of 30mm×30mm×0.5mm, and the number of stacked layers is 80. A blank margin is reserved between the molecular silver paste layer and the piezoelectric ceramic flakes. The side edges of the molecular silver paste layer protrude and extend to form electrode pins, and the projections of the electrode pins on both sides of the piezoelectric ceramic flakes in the thickness direction do not overlap and are located on the same side of the molecular silver paste layer. In addition, a blank margin is also reserved between the glass glaze layer and the piezoelectric ceramic flakes. The side edges of the glass glaze layer are recessed inward to form two pin slots, and the projections of these two pin slots and the electrode pins on both sides of the glass glaze layer in the thickness direction overlap. The series electrodes are printed on the side edges of these second-layer piezoelectric ceramic sheets along the lead-out positions of the electrode pins and form a series circuit.

[0070] The present invention also correspondingly discloses a preparation method for a multi-layer piezoelectric ceramic actuator, including the following steps:

[0071] S1 Weigh the raw materials Pb3O4, ZrO2, TiO2, Nb2O5, Ni2O3, MgO, Sm2O3, SrCO3, BaCO3 according to the chemical stoichiometric formula Pb 0.90 Sr 0.09 Ba 0.01 [(Mg 1 / 3 Nb 2 / 3 ) 0.25 (Zr 0.495 Ti 0.505 ) 0.75 O3 + 0.50mol%Sm2O3 + 0.1mol%Nb2O5. After weighing, first ball-mill and mix for 8h, dry and then calcine at 850°C for 2.5h, and then ball-mill for 4h for the second time. The obtained fine powder is subjected to plasticizing treatment and then formed into a ceramic blank. Among them, the ball-milling media for the first ball-milling and the second ball-milling are zirconium balls, and the weight ratio of the piezoelectric ceramic flake raw material, zirconium balls and water is 1.0:2.2:0.6. Then, successively pass through high-temperature degreasing at 690°C and high-temperature sintering at 1290°C for 3.0h to obtain a ceramic block. Then, successively pass through wire cutting and grinding to obtain piezoelectric ceramic flakes, and obtain the first-layer piezoelectric ceramic sheets;

[0072] S2 First, weigh the raw materials according to 90% molecular silver powder, 2.5% glass powder, and 7.5% organic carrier to obtain molecular silver paste. Then, screen-print the molecular silver paste on the two side surfaces of the piezoelectric ceramic flakes in sequence. The mesh number of the screen printing is 500 meshes, and the printing thickness of the molecular silver paste is 6μm. After each printing is completed, it is dried at 125°C to obtain a molecular silver paste layer with a 2.0mm blank margin reserved between it and the piezoelectric ceramic flakes and with electrode pins;

[0073] First, weigh the raw materials according to 80% glass powder and 20% organic carrier to obtain glass glaze. Then, screen-print the glass glaze on the surface of one of the molecular silver paste layers. The mesh number of the screen printing is 500 meshes, and the printing thickness of the glass glaze layer is 3 μm, obtaining a glass glaze layer with a blank margin of 0.2 mm reserved from the piezoelectric ceramic wafer and with pin slots, and further obtaining the second piezoelectric ceramic wafer.

[0074] Among them, the molecular silver powder is spherical silver powder with a particle size of 0.5 - 2.0 μm, and the particle size distribution is in a normal distribution. D 50 = 1 μm. The glass micropowder is composed of raw materials with the following weight percentages: 70% Bi2O3, 8% B2O3, 15% PbO, 5% Al2O3, and 2% TiO2. The organic carrier is lauryl lactate and ethyl cellulose accounting for 20% of the total weight of lauryl lactate.

[0075] S3 Stack the first piezoelectric ceramic wafer and multiple second piezoelectric ceramic wafers layer by layer from bottom to top according to the predetermined number of layers, clamp and apply pressure, and after drying under pressure at 15 N and 350 °C, print series electrodes on the sides of these second piezoelectric ceramic wafers along the lead-out positions of the electrode pins to obtain a laminated body.

[0076] S4 Place a high-density ceramic plate with the same area as the piezoelectric ceramic wafer on the upper surface of the laminated body, heat at 700 °C for 25 min, and then cool and solidify naturally to obtain a semi-finished piezoelectric actuator.

[0077] S5 Perform polarization treatment on the semi-finished piezoelectric actuator. The polarization voltage is 1.0 kV, the temperature is 130 °C, and the time is 25 min to obtain a multi-layer piezoelectric ceramic actuator.

[0078] Example 4: A multi-layer piezoelectric ceramic actuator disclosed in the present invention is different from Example 1 in that it includes a first piezoelectric ceramic wafer, multiple second piezoelectric ceramic wafers, a high-density ceramic plate, and series electrodes provided on the first piezoelectric ceramic wafer and these second piezoelectric ceramic wafers, which are stacked layer by layer from bottom to top. Among them, the first piezoelectric ceramic wafer includes a piezoelectric ceramic wafer and molecular silver paste layers printed on both side surfaces of the piezoelectric ceramic wafer. The second piezoelectric ceramic wafer includes the first piezoelectric ceramic wafer and a glass glaze layer printed on the lower side surface of the first piezoelectric ceramic wafer. The high-density ceramic plate is set as an alumina ceramic wafer.

[0079] To achieve the effect of a parallel circuit for the series electrodes, the multi-layer piezoelectric ceramic actuator is set to be square. The piezoelectric ceramic thin sheets are square thin sheets with dimensions of 10mm×10mm×0.3mm, and the number of stacked layers is 50. A blank margin is reserved between the molecular silver paste layer and the piezoelectric ceramic thin sheets. The side edges of the molecular silver paste layer protrude and extend to form electrode pins, and the projections of the electrode pins on both sides of the piezoelectric ceramic thin sheets in the thickness direction do not overlap and are located on the same side of the molecular silver paste layer. In addition, a blank margin is also reserved between the glass glaze layer and the piezoelectric ceramic thin sheets. The side edges of the glass glaze layer are recessed inward to form two pin slots, and the projections of these two pin slots and the electrode pins on both sides of the glass glaze layer in the thickness direction overlap. The series electrodes are printed on the side edges of these second-layer piezoelectric ceramic sheets along the lead-out positions of the electrode pins to form a series circuit.

[0080] The present invention correspondingly also discloses a preparation method for a multi-layer piezoelectric ceramic actuator, including the following steps.

[0081] S1 Weigh the raw materials Pb3O4, ZrO2, TiO2, Nb2O5, Ni2O3, MgO, Sm2O3, SrCO3, BaCO3 according to the chemical stoichiometric formula Pb 0.90 Sr 0.09 Ba 0.01 [(Mg 1 / 3 Nb 2 / 3 ) 0.25 (Zr 0.495 Ti 0.505 ) 0.75 O3 + 0.50mol% Sm2O3 + 0.1mol% Nb2O5. After weighing, first ball-mill and mix for 5h, dry and then calcine at 800°C for 2.0h. Then, ball-mill for the second time for 12h. After the obtained fine powder is subjected to plasticizing treatment, it is formed into a ceramic blank. Among them, the ball-milling media for the first ball-milling and the second ball-milling are zirconium balls, and the weight ratio of the piezoelectric ceramic thin sheet raw materials, zirconium balls and water is 1.0:1.9:0.8. Then, it is successively subjected to high-temperature degreasing at 710°C and high-temperature sintering at 1300°C for 4.0h to obtain a ceramic block. Then, it is successively subjected to wire cutting and grinding to obtain piezoelectric ceramic thin sheets, and the first-layer piezoelectric ceramic sheets are obtained.

[0082] S2 First, weigh the raw materials according to 86% molecular silver powder, 5% glass powder, and 9% organic carrier to obtain molecular silver paste. Then, screen-print the molecular silver paste on the two side surfaces of the piezoelectric ceramic thin sheets in sequence. The mesh number of the screen printing is 400 meshes, and the printing thickness of the molecular silver paste is 5μm. After each printing is completed, it is dried at 150°C to obtain a molecular silver paste layer with a 2.0mm blank margin reserved between it and the piezoelectric ceramic thin sheets and with electrode pins.

[0083] First, weigh the raw materials according to 75% glass powder and 25% organic carrier to obtain glass glaze. Then, screen-print the glass glaze on the surface of one of the molecular silver paste layers. The mesh number of the screen printing is 400 meshes, and the printing thickness of the glass glaze layer is 2 μm, obtaining a glass glaze layer with a blank margin of 0.2 mm reserved from the piezoelectric ceramic sheet and with a pin groove, and further obtaining the second piezoelectric ceramic sheet.

[0084] Among them, the molecular silver powder is spherical silver powder with a particle size of 0.5 - 2.0 μm, and the particle size distribution is a normal distribution. D 50 = 1 μm. The glass micro-powder is composed of raw materials with the following weight percentages: 68% Bi2O3, 16% B2O3, 10% PbO, 3% Al2O3, and 3% TiO2. The organic carrier is dioctyl phthalate and ethyl cellulose accounting for 16% of the total weight of dioctyl phthalate.

[0085] S3 Stack the first piezoelectric ceramic sheet and multiple second piezoelectric ceramic sheets layer by layer from bottom to top according to the predetermined number of layers, and clamp and press them. After pressing and drying at 25 N and 300 °C, print series electrodes on the sides of these second piezoelectric ceramic sheets along the lead-out positions of the electrode pins to obtain a laminated body.

[0086] S4 Place a high-density ceramic plate with the same area as the piezoelectric ceramic sheet on the upper surface of the laminated body, heat it at 800 °C for 40 min, and then cool it naturally to solidify to obtain a semi-finished piezoelectric actuator.

[0087] S5 Perform polarization treatment on the semi-finished piezoelectric actuator. The polarization voltage is 0.9 kV, the temperature is 125 °C, and the time is 30 min to obtain a multi-layer piezoelectric ceramic actuator.

[0088] Embodiment 5: A multi-layer piezoelectric ceramic actuator disclosed in the present invention, which is different from Embodiment 1 in that it includes a first piezoelectric ceramic sheet, multiple second piezoelectric ceramic sheets, and a high-density ceramic plate stacked layer by layer from bottom to top, and series electrodes provided on the first piezoelectric ceramic sheet and these second piezoelectric ceramic sheets. Among them, the first piezoelectric ceramic sheet includes a piezoelectric ceramic sheet and molecular silver paste layers printed on both side surfaces of the piezoelectric ceramic sheet. The second piezoelectric ceramic sheet includes the first piezoelectric ceramic sheet and a glass glaze layer printed on the lower side surface of the first piezoelectric ceramic sheet. The high-density ceramic plate is provided as an alumina ceramic sheet.

[0089] To achieve the effect of parallel circuits for the series electrodes, the multi-layer piezoelectric ceramic actuator is set to be square. The piezoelectric ceramic flakes are square flakes with dimensions of 10mm×10mm×0.3mm, and the number of stacked layers is 100. There is a blank margin reserved between the molecular silver paste layer and the piezoelectric ceramic flakes. The side edges of the molecular silver paste layer protrude and extend to form electrode pins, and the projections of the electrode pins on both sides of the piezoelectric ceramic flakes in the thickness direction do not overlap and are located on the same side of the molecular silver paste layer. In addition, there is also a blank margin reserved between the glass glaze layer and the piezoelectric ceramic flakes. The side edges of the glass glaze layer are recessed inward to form two pin slots, and the projections of these two pin slots and the electrode pins on both sides of the glass glaze layer in the thickness direction overlap. The series electrodes are printed on the side edges of these second-layer piezoelectric ceramic sheets along the lead-out positions of the electrode pins to form a series circuit.

[0090] The present invention also correspondingly discloses a preparation method for a multi-layer piezoelectric ceramic actuator, including the following steps.

[0091] S1 Weigh the raw materials Pb3O4, ZrO2, TiO2, Nb2O5, Ni2O3, MgO, Sm2O3, SrCO3, BaCO3 according to the chemical stoichiometric formula Pb 0.90 Sr 0.09 Ba 0.01 [(Mg 1 / 3 Nb 2 / 3 ) 0.25 (Zr 0.495 Ti 0.505 ) 0.75 O3 + 0.50mol% Sm2O3 + 0.1mol% Nb2O5. After weighing, first ball-mill and mix for 10h, dry and then calcine at 860°C for 2.0h, and then ball-mill for the second time for 16h. After the obtained fine powder is subjected to plasticizing treatment, a ceramic green body is formed. Among them, the ball-milling media for the first ball-milling and the second ball-milling are zirconium balls, and the weight ratio of the piezoelectric ceramic flake raw material, zirconium balls and water is 1.0:2.1:0.9. Then, successively undergo high-temperature degassing at 720°C and high-temperature sintering at 1320°C for 2.5h to obtain a ceramic block. Then, successively undergo wire cutting and grinding to obtain piezoelectric ceramic flakes, and obtain the first-layer piezoelectric ceramic sheets.

[0092] S2 First, weigh the raw materials according to 87% molecular silver powder, 4% glass powder, and 9% organic carrier to obtain molecular silver paste. Then, screen-print the molecular silver paste on the two side surfaces of the piezoelectric ceramic flakes in sequence. The mesh number of the screen printing is 300 meshes, and the printing thickness of the molecular silver paste is 6μm. After each printing is completed, it is dried at 250°C to obtain a molecular silver paste layer with a 2.0mm blank margin reserved between it and the piezoelectric ceramic flakes and with electrode pins.

[0093] First, weigh the raw materials according to 83% glass powder and 17% organic carrier to obtain the glass glaze. Then, screen-print the glass glaze on the surface of one of the molecular silver paste layers. The mesh number of the screen printing is 300 meshes, and the printing thickness of the glass glaze layer is 2 μm, obtaining a glass glaze layer with a 0.3 mm blank margin reserved between it and the piezoelectric ceramic wafer and with pin slots, and further obtaining the second piezoelectric ceramic wafer.

[0094] Among them, the molecular silver powder is spherical silver powder with a particle size of 0.5 - 2.0 μm, and the particle size distribution is a normal distribution. D 50 = 1 μm. The glass micropowder is composed of raw materials with the following weight percentages: 62% Bi2O3, 20% B2O3, 12% PbO, 5% Al2O3, and 1% TiO2; the organic carrier is dimethyl phthalate and ethyl cellulose accounting for 18% of the total weight of dimethyl phthalate.

[0095] S3 Stack the first piezoelectric ceramic wafer and multiple second piezoelectric ceramic wafers layer by layer from bottom to top according to the predetermined number of layers, clamp and apply pressure, and after drying under pressure at 30 N and 250 °C, print series electrodes on the sides of these second piezoelectric ceramic wafers along the lead-out positions of the electrode pins to obtain a laminated body.

[0096] S4 Place a high-density ceramic plate with the same area as the piezoelectric ceramic wafer on the upper surface of the laminated body, heat it at 720 °C for 35 min and then cool it naturally to solidify, obtaining a semi-finished piezoelectric actuator.

[0097] S5 Perform polarization treatment on the semi-finished piezoelectric actuator. The polarization voltage is 3.0 kV, the temperature is 115 °C, and the time is 10 min to obtain a multi-layer piezoelectric ceramic actuator.

[0098] Example 6: Refer to Figures 4 - 6 , a multi-layer piezoelectric ceramic actuator disclosed in the present invention. The difference from Example 1 is that it includes a first piezoelectric ceramic wafer, multiple second piezoelectric ceramic wafers, and a high-density ceramic plate stacked layer by layer from bottom to top, and series electrodes provided on the first piezoelectric ceramic wafer and these second piezoelectric ceramic wafers. Among them, the first piezoelectric ceramic wafer includes a piezoelectric ceramic wafer and molecular silver paste layers printed on both side surfaces of the piezoelectric ceramic wafer. The second piezoelectric ceramic wafer includes the first piezoelectric ceramic wafer and a glass glaze layer printed on the lower side surface of the first piezoelectric ceramic wafer. The high-density ceramic plate is set as an alumina ceramic wafer.

[0099] To achieve the effect of a parallel circuit for the series electrodes, the multi-layer piezoelectric ceramic actuator is set to be circular. The piezoelectric ceramic thin sheets are circular sheets with a diameter of Ф15mm × 1.0mm, and the number of stacked layers is 20. There is a blank margin reserved between the molecular silver paste layer and the piezoelectric ceramic thin sheets. The side edges of the molecular silver paste layer protrude and extend to form electrode pins, and the projections of the electrode pins on both sides of the piezoelectric ceramic thin sheets in the thickness direction do not overlap and are located on the opposite sides of the molecular silver paste layer. In addition, there is also a blank margin reserved between the glass glaze layer and the piezoelectric ceramic thin sheets. The side edges of the glass glaze layer are recessed inward to form two pin slots, and the projections of these two pin slots and the electrode pins on both sides of the glass glaze layer in the thickness direction overlap. The series electrodes are printed on the side edges of these second-layer piezoelectric ceramic sheets along the lead-out positions of the electrode pins to form a series circuit.

[0100] The present invention also correspondingly discloses a preparation method for a multi-layer piezoelectric ceramic actuator, including the following steps.

[0101] S1 Weigh the raw materials Pb3O4, ZrO2, TiO2, Nb2O5, Ni2O3, MgO, Sm2O3, SrCO3, BaCO3 according to the chemical stoichiometric formula Pb 0.90 Sr 0.09 Ba 0.01 [(Mg 1 / 3 Nb 2 / 3 ) 0.25 (Zr 0.495 Ti 0.505 ) 0.75 O3 + 0.50mol% Sm2O3 + 0.1mol% Nb2O5. After weighing, first ball-mill and mix for 4h, dry and then calcine at 840°C for 2.0h, and then ball-mill for 6h for the second time. The obtained fine powder is subjected to plasticizing treatment and then formed into a ceramic blank. Among them, the ball-milling media for the first ball-milling and the second ball-milling are zirconium balls, and the weight ratio of the piezoelectric ceramic thin sheet raw material, zirconium balls and water is 1.0:2.0:0.75. Then, successively pass through high-temperature degassing at 700°C and high-temperature sintering at 1300°C for 2.0h to obtain a ceramic block. Then, successively pass through wire cutting and grinding to obtain piezoelectric ceramic thin sheets, and obtain the first-layer piezoelectric ceramic sheets.

[0102] S2 First, weigh the raw materials according to 89% of molecular silver powder, 2.5% of glass powder, and 8.5% of organic carrier to obtain molecular silver paste. Then, screen-print the molecular silver paste on the two side surfaces of the piezoelectric ceramic thin sheets in sequence. The mesh number of the screen printing is 350 meshes, and the printing thickness of the molecular silver paste is 5μm. After each printing is completed, it is dried at 220°C to obtain a molecular silver paste layer with a blank margin of 1.5mm reserved between it and the piezoelectric ceramic thin sheets and with electrode pins.

[0103] First, weigh the raw materials according to 75% glass powder and 25% organic carrier to obtain glass glaze. Then, screen-print the glass glaze on the surface of one of the molecular silver paste layers. The mesh number of the screen printing is 350 meshes, and the printing thickness of the glass glaze layer is 2 μm, obtaining a glass glaze layer with a 0.2 mm blank margin reserved from the piezoelectric ceramic wafer and with a pin groove, and further obtaining the second piezoelectric ceramic wafer.

[0104] Among them, the molecular silver powder is spherical silver powder with a particle size of 0.5 - 2.0 μm, and the particle size distribution is in a normal distribution. D 50 = 1 μm. The glass micropowder is composed of raw materials with the following weight percentages: 65% Bi2O3, 15% B2O3, 20% PbO, 0% Al2O3, and 0% TiO2; the organic carrier is butyl carbitol acetate and ethyl cellulose accounting for 14% of the total weight of butyl carbitol acetate.

[0105] S3 Stack the first piezoelectric ceramic wafer and multiple second piezoelectric ceramic wafers layer by layer from bottom to top according to the predetermined number of layers, clamp and apply pressure, and after pressing and drying at 15 N and 150 °C, print series electrodes on the sides of these second piezoelectric ceramic wafers along the lead-out positions of the electrode pins to obtain a laminated body.

[0106] S4 Place a high-density ceramic plate with the same area as the piezoelectric ceramic wafer on the upper surface of the laminated body, heat it at 750 °C for 30 min, and then cool it naturally to solidify to obtain a semi-finished piezoelectric actuator.

[0107] S5 Perform polarization treatment on the semi-finished piezoelectric actuator. The polarization voltage is 3.0 kV, the temperature is 110 °C, and the time is 30 min to obtain a multi-layer piezoelectric ceramic actuator.

[0108] Embodiment 7: A multi-layer piezoelectric ceramic actuator disclosed in the present invention, which is different from Embodiment 1 in that it includes a first piezoelectric ceramic wafer, multiple second piezoelectric ceramic wafers, a high-density ceramic plate stacked layer by layer from bottom to top in sequence, and series electrodes provided on the first piezoelectric ceramic wafer and these second piezoelectric ceramic wafers. Among them, the first piezoelectric ceramic wafer includes a piezoelectric ceramic wafer and molecular silver paste layers printed on both side surfaces of the piezoelectric ceramic wafer. The second piezoelectric ceramic wafer includes the first piezoelectric ceramic wafer and a glass glaze layer printed on the lower side surface of the first piezoelectric ceramic wafer. The high-density ceramic plate is set as an alumina ceramic wafer.

[0109] To achieve the effect of parallel circuits for the series electrodes, the multi-layer piezoelectric ceramic actuator is set to be circular. The piezoelectric ceramic thin sheets are circular sheets with a diameter of Ф15mm × 1.0mm, and the number of stacked layers is 50. There is a blank margin reserved between the molecular silver paste layer and the piezoelectric ceramic thin sheets. The side edges of the molecular silver paste layer protrude and extend to form electrode pins, and the projections of the electrode pins on both sides of the piezoelectric ceramic thin sheets in the thickness direction do not overlap and are located on the opposite sides of the molecular silver paste layer. In addition, there is also a blank margin reserved between the glass glaze layer and the piezoelectric ceramic thin sheets. The side edges of the glass glaze layer are recessed inward to form two pin slots, and the projections of these two pin slots and the electrode pins on both sides of the glass glaze layer in the thickness direction overlap. The series electrodes are printed on the side edges of these second-layer piezoelectric ceramic sheets along the lead-out positions of the electrode pins to form a series circuit.

[0110] The present invention also correspondingly discloses a preparation method for a multi-layer piezoelectric ceramic actuator, including the following steps:

[0111] S1 Weigh the raw materials Pb3O4, ZrO2, TiO2, Nb2O5, Ni2O3, MgO, Sm2O3, SrCO3, BaCO3 according to the chemical stoichiometric formula Pb 0.90 Sr 0.09 Ba 0.01 [(Mg 1 / 3 Nb 2 / 3 ) 0.25 (Zr 0.495 Ti 0.505 ) 0.75 O3 + 0.50mol% Sm2O3 + 0.1mol% Nb2O5. After weighing, first ball-mill and mix for 6h, dry and then calcine at 820°C for 2.5h, and then ball-mill for 8h for the second time. The obtained fine powder is subjected to plasticizing treatment and then molded to obtain a ceramic blank. Among them, the ball-milling media for the first ball-milling and the second ball-milling are zirconium balls, and the weight ratio of the piezoelectric ceramic thin sheet raw material, zirconium balls and water is 1.0:2.1:0.7. Then, successively pass through high-temperature degassing at 710°C and high-temperature sintering at 1310°C for 3.5h to obtain a ceramic block. Then, successively pass through wire cutting and grinding to obtain piezoelectric ceramic thin sheets, and obtain the first-layer piezoelectric ceramic sheets;

[0112] S2 First, weigh the raw materials according to 85% molecular silver powder, 1.5% glass powder, and 13.5% organic carrier to obtain molecular silver paste. Then, screen-print the molecular silver paste on the two side surfaces of the piezoelectric ceramic thin sheets in sequence. The mesh number of the screen printing is 300 meshes, and the printing thickness of the molecular silver paste is 4μm. After each printing is completed, it is dried at 180°C to obtain a molecular silver paste layer with a 1.0mm blank margin reserved between it and the piezoelectric ceramic thin sheets and with electrode pins;

[0113] First, weigh the raw materials according to 80% glass powder and 20% organic carrier to obtain glass glaze. Then, screen-print the glass glaze on the surface of one of the molecular silver paste layers. The mesh number of the screen printing is 300 meshes, and the printing thickness of the glass glaze layer is 1 μm, so as to obtain a glass glaze layer with a 0.2 mm blank margin reserved from the piezoelectric ceramic wafer and with a pin groove, and then obtain the second piezoelectric ceramic wafer.

[0114] Among them, the molecular silver powder is spherical silver powder with a particle size of 0.5 - 2.0 μm, and the particle size distribution is in a normal distribution. D 50 = 1 μm, and the glass micropowder is composed of raw materials with the following weight percentages: 65% Bi2O3, 17% B2O3, 13% PbO, 3% Al2O3, and 2% TiO2; the organic carrier is terpineol and ethyl cellulose accounting for 12% of the total weight of terpineol.

[0115] S3 Stack the first piezoelectric ceramic wafer and multiple second piezoelectric ceramic wafers layer by layer from bottom to top according to the predetermined number of layers, clamp and apply pressure, and after pressing and drying at 25 N and 350 °C, print series electrodes on the sides of these second piezoelectric ceramic wafers along the lead-out position of the electrode pins to obtain a laminated body.

[0116] S4 Place a high-density ceramic plate with the same area as the piezoelectric ceramic wafer on the upper surface of the laminated body, heat it at 760 °C for 20 min and then cool it naturally to solidify, obtaining a semi-finished piezoelectric actuator.

[0117] S5 Perform polarization treatment on the semi-finished piezoelectric actuator. The polarization voltage is 2.0 kV, the temperature is 120 °C, and the time is 25 min to obtain a multi-layer piezoelectric ceramic actuator.

[0118] Comparative Example

[0119] Comparative Example 1: A multi-layer piezoelectric ceramic actuator disclosed in the present invention. The difference from Example 1 is that the formula of the piezoelectric ceramic wafer has a chemical stoichiometric general formula of Pb 0.90 Sr 0.09 Ba 0.01 [(Mg 1 / 3 Nb 2 / 3 ) 0.25 (Zr 0.49 Ti 0.51 ) 0.75 O3 + 1.5 mol% Sm2O3 + 0.1 mol% Nb2O5.

[0120] Comparative Example 2: A multi-layer piezoelectric ceramic actuator disclosed in the present invention. The difference from Example 1 is that the piezoelectric ceramic is sintered at a high temperature of 1250 °C for 2 h.

[0121] Comparative Example 3: A multi-layer piezoelectric ceramic actuator disclosed in the present invention, which is different from Example 1 in that the second piezoelectric ceramic sheet includes a piezoelectric ceramic thin sheet, a molecular silver paste layer printed on the front surface of the piezoelectric ceramic thin sheet, and a molecular silver paste layer printed on the back surface of the piezoelectric ceramic thin sheet in sequence.

[0122] Comparative Example 4: A multi-layer piezoelectric ceramic actuator disclosed in the present invention, which is different from Example 1 in that the second piezoelectric ceramic sheet includes a piezoelectric ceramic thin sheet, a molecular silver paste layer and a glass glaze layer printed on the front surface of the piezoelectric ceramic thin sheet in sequence, and a molecular silver paste layer and a glass glaze layer printed on the back surface of the piezoelectric ceramic thin sheet in sequence.

[0123] Comparative Example 5: A multi-layer piezoelectric ceramic actuator disclosed in the present invention, which is different from Example 1 in that in S3, the drying treatment is directly carried out without using a fixture to apply pressure and clamp.

[0124] Comparative Example 6: A multi-layer piezoelectric ceramic actuator disclosed in the present invention, which is different from Example 1 in that in S4, an alumina ceramic sheet is placed on the upper surface of the sheet stack, heated at 600 °C for 30 min and then naturally cooled and solidified to obtain a semi-finished piezoelectric actuator.

[0125] Performance detection test

[0126] The multi-layer piezoelectric ceramic actuators prepared in Examples 1-7 and Comparative Examples 1-6 were subjected to performance detection, and the detection results are shown in Table 1.

[0127] Table 1

[0128] Single - layer ceramic capacitor / nF tanδ (%) Drive voltage / V Static capacitance / nF Displacement / μm Others Example 1 83.6 1.48 500 1670 10.50 / Example 2 83.6 1.48 500 4121 26.25 / Example 3 83.6 1.48 500 6752 42.31 / Example 4 11.4 1.48 300 571 15.75 / Example 5 11.4 1.48 300 1128 31.58 / Example 6 7.54 1.48 300 151.2 21.05 / Example 7 7.54 1.48 300 381.5 51.69 / Comparative Example 1 69.8 1.90 500 1396 8.55 / Comparative Example 2 78.6 1.69 500 1572 9.64 / Comparative Example 3 83.6 1.48 / / / Multi - layer ceramics cannot be cured Comparative Example 4 83.6 1.48 500 1570 10.13 / Comparative Example 5 83.6 1.48 / / / The driver cracks when voltage is applied Comparative Example 6 80.5 1.68 500 1623 9.95 /

[0129] From Table 1 and Figure 1 It can be seen that by adopting the chemical stoichiometric general formula of the piezoelectric ceramic thin sheet in Examples 1-7 of the present invention and through optimization, a piezoelectric ceramic sheet with high capacitance and low loss can be obtained; for multi-layer actuators prepared from the same single-layer piezoelectric ceramic thin sheet, they have linear capacitance, displacement and stiffness, which gradually increase with the increase of the stack thickness; among them, the displacement of Example 3 reaches 42.31 μm under a driving voltage of 500 V;

[0130] The chemical stoichiometric general formula of the piezoelectric ceramic thin sheet in Comparative Example 1 is different from that in Example 1 in that the content of Sm2O3 and the Zr / Ti ratio are adjusted, and the electrical properties of the piezoelectric ceramic thin sheet decline to a certain extent, and the performance of the prepared multi-layer piezoelectric actuator is also poor;

[0131] The piezoelectric ceramic of Comparative Example 2 is different from that of Example 1 in that the piezoelectric ceramic is sintered at a high temperature of 1250 °C for 2 h. Due to inappropriate sintering conditions, the performance of the piezoelectric ceramic does not reach the maximum value, and the performance of the prepared multi-layer piezoelectric actuator is also poor;

[0132] The piezoelectric ceramic sheet of Comparative Example 3 is different from that of Example 1 in that no glass enamel layer is printed on both sides of the piezoelectric ceramic sheet, and it is heated at 700-800 °C for 30 min, and the integration of the multi-layer piezoelectric actuator is not achieved, and the test conditions for the multi-layer actuator are not available;

[0133] A multi-layer piezoelectric ceramic actuator described in Comparative Example 4 is different from that of Example 1 in that glass enamel layers are printed on both sides of the sheet, and the thickness of the glass enamel layer of the second piezoelectric ceramic sheet is increased. The driving performance of the prepared multi-layer piezoelectric actuator decreases due to the increase in the proportion of the non-piezoelectric phase volume;

[0134] A multi-layer piezoelectric ceramic actuator described in Comparative Example 5 is different from that of Example 1 in that in S3, it is directly dried without using a fixture to apply pressure and clamp. Cracking occurs when a voltage is applied to the actuator;

[0135] A multi-layer piezoelectric ceramic actuator described in Comparative Example 6 is different from that of Example 1 in that in S4, an alumina ceramic sheet is placed on the upper surface of the sheet stack, and after heating at 600 °C for 30 min and then naturally cooling and curing, a piezoelectric actuator semi-finished product is obtained. The capacitance of the single-layer piezoelectric ceramic sheet decreases, resulting in a decrease in the performance of the assembled multi-layer actuator.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A preparation method of a multi-layer piezoelectric ceramic actuator, characterized in that: The multi-layer piezoelectric ceramic actuator includes a plurality of piezoelectric ceramic wafers stacked, a molecular silver paste layer printed on both side surfaces of the piezoelectric ceramic wafers, and a glass glaze layer disposed between adjacent two molecular silver paste layers; wherein, the chemical stoichiometric general formula of the piezoelectric ceramic wafer formulation is, Pb 1-m-n Sr m Ba n [(Mg 1 / 3 Nb 2 / 3 ) x (Ni 1 / 3 Nb 2 / 3 ) y (Zr z Ti 1-z ) 1-x-y O3+ a mol%Sm2O3+ b mol%Nb2O5, x = 0.15~0.25, y = 0~0.05, z = 0.45~0.55, m = 0.02~0.10, n = 0~0.05, a = 0~1.20, b = 0~0.40; The preparation method includes the following steps: S1: After weighing the raw materials Pb3O4, ZrO2, TiO2, Nb2O5, Ni2O3, MgO, Sm2O3, SrCO3, and BaCO3 according to the chemical stoichiometric general formula, they are successively subjected to first ball milling, drying and calcination, second ball milling, and plasticizing treatment, and then formed into a ceramic green body. After that, they are successively subjected to high-temperature degreasing and high-temperature sintering to obtain a ceramic block. Then, they are successively subjected to warp cutting and grinding to obtain a piezoelectric ceramic thin sheet; S2: Screen-print molecular silver paste layers on both side surfaces of the piezoelectric ceramic thin sheet in sequence. After each printing, drying treatment is carried out to obtain a first-layer piezoelectric ceramic sheet. Then, a glass glaze layer is screen-printed on the lower side surface of the first-layer piezoelectric ceramic sheet to obtain a second-layer piezoelectric ceramic sheet; S3: Stack the first-layer piezoelectric ceramic sheet and multiple second-layer piezoelectric ceramic sheets layer by layer from bottom to top according to the predetermined number of layers, dry them under clamping and pressing conditions, and then print series electrodes on the sides of the first-layer piezoelectric ceramic sheet and these second-layer piezoelectric ceramic sheets to obtain a laminated body; S4: Place a high-density ceramic plate on the upper side surface of the laminated body, heat it at high temperature and then cool it naturally to cure, obtaining a semi-finished piezoelectric actuator; S5: Subject the semi-finished piezoelectric actuator to polarization treatment to obtain a multi-layer piezoelectric ceramic actuator.

2. The preparation method of a multi-layer piezoelectric ceramic actuator according to claim 1, wherein: The molecular silver paste layer is composed of raw materials containing the following weight percentages: 85 - 90% molecular silver powder, 0.5 - 5.0% glass powder, and 5 - 30% organic carrier; the printing thickness of the molecular silver paste layer is 1 - 3μm, and a blank margin of 0.5 - 2.0mm is reserved between the molecular silver paste layer and the piezoelectric ceramic thin sheet.

3. The preparation method of a multi-layer piezoelectric ceramic actuator according to claim 2, characterized in that: The side of the molecular silver paste layer protrudes and extends to form electrode pins, and the projections of the electrode pins on both sides of the piezoelectric ceramic thin sheet in the thickness direction do not overlap and are located on the same side or opposite sides of the molecular silver paste layer.

4. The preparation method of a multi-layer piezoelectric ceramic actuator according to claim 3, characterized in that: The glass glaze layer is composed of raw materials containing the following weight percentages: 70 - 85% glass powder; 5 - 30% organic carrier; the printing thickness of the glass glaze layer is 1 - 3μm, and a blank margin of 0.1 - 0.3mm is reserved between the glass glaze layer and the piezoelectric ceramic thin sheet.

5. The preparation method of a multi-layer piezoelectric ceramic actuator according to claim 4, characterized in that: The side of the glass glaze layer is recessed inward to form two pin slots, and the projections of this pair of pin slots and the electrode pins on both sides of the glass glaze layer in the thickness direction overlap.

6. The preparation method of a multi-layer piezoelectric ceramic actuator according to claim 1, characterized in that: In S1, the first ball milling time is 2 - 10h, the calcination temperature is 800 - 860°C, the time is 1.5 - 2.5h, and the second ball milling time is 4 - 16h; the high-temperature degreasing temperature is 680 - 720°C, and the high-temperature sintering temperature is 1280 - 1320°C, and the time is 1.5 - 4h.

7. The preparation method of a multi-layer piezoelectric ceramic actuator according to claim 1, wherein: In S2, the mesh number of screen printing is 200 - 500 meshes; after each screen printing of the molecular silver paste layer, drying treatment is carried out at 100 - 250°C.

8. The preparation method of a multi-layer piezoelectric ceramic actuator according to claim 1, characterized in that: In S3, the clamping and pressing pressure is 10 - 30N, and the drying temperature is 150 - 350°C.

9. The preparation method of a multi-layer piezoelectric ceramic actuator according to claim 1, characterized in that: In S4, the high-temperature heating temperature is 700 - 800°C, and the time is 20 - 40min.

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