Chip type composite bending driver and preparation process thereof

Abstract

The invention relates to a chip type composite bending driver and a preparation process thereof, and relates to the technical field of drivers, and the preparation process comprises the following steps: S1, preparing lead barium zirconate nanofibers; s2, introducing the lead barium zirconate nanofibers obtained in the step S1 into a polyvinylidene fluoride substrate to prepare a composite solution; s3, the shape memory alloy sheet is subjected to aging training to form a memory bending shape; s4, shape memory alloy sheets meeting the shape requirement are selected; s5, enabling the composite solution prepared in the step S2 to form a composite film layer on the shape memory alloy sheet meeting the shape requirement in the step S4; s6, forming a surface electrode layer on the composite film layer; and S7, the side, away from the composite thin film layer, of the shape memory alloy sheet and the side, away from the composite thin film layer, of the surface electrode layer are connected with outer guide wires, and the sheet type composite driver is obtained. The application has the effect of reducing the response time of the driver.

Description

Technical Field

[0001] The present invention relates to the technical field of actuators, and in particular to a sheet-type composite bending actuator and a preparation process thereof. Background Art

[0002] Shape memory alloy actuators have the advantages of simple structure, large driving force, high power-to-weight ratio, and rapid response. The cooling time of the shape memory alloy actuator affects the response speed of the actuator.

[0003] Currently, the cooling method for shape memory alloy actuators is mainly natural cooling, which takes a long time, generally tens of seconds, resulting in a prolonged response cycle of the shape memory alloy actuator. Summary of the Invention

[0004] In order to reduce the response time of the actuator, the present application provides a sheet-type composite bending actuator and a preparation process thereof.

[0005] The preparation process of a sheet-type composite bending actuator provided in this application adopts the following technical solution: A process for preparing a sheet-type composite bending actuator comprises the following steps: Step S1, preparing lead barium zirconate nanofibers; Step S2, introducing the lead barium zirconate nanofibers obtained in step S1 into a polyvinylidene fluoride substrate to prepare a composite solution; Step S3: performing aging training on the shape memory alloy sheet to form a memory bending shape; Step S4, selecting a shape memory alloy sheet that meets the shape requirements; Step S5, forming a composite thin film layer on the shape memory alloy sheet that meets the shape requirements in step S4 using the composite solution prepared in step S2; Step S6, forming a surface electrode layer on the composite film layer; Step S7: connecting external guide wires to the side of the shape memory alloy sheet away from the composite film layer and the side of the surface electrode layer away from the composite film layer to obtain a chip-type composite driver.

[0006] Preferably, step S1 includes the following steps: Step S11: 2.913 g of lead acetate trihydrate and 0.409 g of barium acetate were dissolved in 1.59 ml of glacial acetic acid and 1.89 ml of deionized water, stirred at 60° C. for 30 min, and then cooled to room temperature to obtain a first mixed solution. Lead acetate trihydrate was then added to the first mixed solution to obtain a first configured solution, wherein the mass of lead element in the first configured solution was 1.2 times the mass of lead element in the first mixed solution. 3.743 g of zirconium n-propoxide solution was dissolved in 0.59 ml of 2-ethylene glycol methyl ether solution, stirred at room temperature for 10 min to obtain a second mixed solution. 0.79 ml of acetylacetone was added to the second mixed solution, and stirred at room temperature for 30 min to obtain a second configured solution. Step S12: Mix the first solution, the second solution, and 4.99 ml of deionized water, and stir at room temperature for 2 hours; Step S13, the mixed solution after stirring for 2 hours in step S12 is allowed to stand and age for 24 hours; Step S14: filtering the mixed solution after aging for 24 hours in step S13 using 0.2 μm filter paper; Step S15, mixing 0.65 g of polyvinyl pyrrolidone with the mixed solution obtained by filtering in step S14, and stirring at room temperature for 2 h; Step S16: jet-spinning the mixed solution stirred for 2 h in step S15 in a strong electric field to obtain a lead barium zirconate nanoprecursor with a concentration of 0.8 mol / L, wherein the spinning voltage is 11 kV, the spinning current is 1.7 A, the distance from the spinning needle to the spinning collector is 8 cm, and the spinning rate is 0.7 ml / h; Step S17, placing 0.8 mol / L of lead barium zirconate precursor nanofibers in a sintering furnace, first raising the sintering furnace temperature from room temperature to 350°C at a rate of 3°C / min and then keeping it at 350°C for 30 minutes, then raising the sintering furnace temperature from 350°C to 450°C at a rate of 5°C / min and then keeping it at 450°C for 60 minutes, and finally raising the sintering furnace temperature from 450°C to 750°C at a rate of 5°C / min and keeping it at a constant temperature for 3 hours to obtain lead barium zirconate nanofibers.

[0007] Preferably, step S2 includes the following steps: Step S21: at room temperature, 0.32 g of lead barium zirconate nanofibers were uniformly dispersed in 15 ml of N,N-dimethoxyformamide suspension solution and then ultrasonically treated for 0.5 h to 1.5 h; Step S22: at room temperature, slowly add 3.00 g of polyvinylidene fluoride powder into the solution after ultrasonic treatment in step S21; Step S23, the solution mixed with polyvinylidene fluoride powder in step S22 is magnetically stirred at room temperature for 19 hours, and then vacuum degassed for 30 minutes; In step S24, the mixed solution after vacuum degassing for 30 minutes in step S23 is allowed to stand to obtain a composite solution.

[0008] Preferably, step S3 includes the following steps: Step S31, fixing the ends of a shape memory alloy sheet to the ends of a mold to bend the shape memory alloy sheet, wherein the nickel atomic content of the shape memory alloy sheet is ≥50 at%, the length of the shape memory alloy sheet is between 80 mm and 120 mm, the width of the shape memory alloy sheet is between 3 mm and 9 mm, and the height of the shape memory alloy sheet is between 0.1 mm and 0.5 mm; Step S32: After placing the shape memory alloy sheet and the mold in step S31 in a heating furnace, the temperature of the heating furnace is raised from 20° C. to 450° C. within 40 minutes, and then the shape memory alloy sheet and the mold are kept in the heating furnace at 450° C. for 1 hour; Step S33: quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20° C. water to cool for 3 minutes; Step S34: first, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S33 in a 450° C. heating furnace for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20° C. water for cooling for 3 minutes; Step S35: first, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S34 in a 450° C. heating furnace for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20° C. water for cooling for 3 minutes; Step S36: first, place the shape memory alloy sheet and the mold that have been cooled for 3 minutes in step S35 in a 450° C. heating furnace for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20° C. water for cooling for 3 minutes; Step S37: First, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S36 in a 450°C heating furnace for constant temperature treatment for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20°C water for cooling for 3 minutes.

[0009] Preferably, step S4 includes the following steps: S41, removing the shape memory alloy sheet from the mold; S42, flattening or twisting the shape memory alloy sheet into any shape by applying an external force; S43, placing the shape memory alloy sheet in step S42 in 80°C water for 5 minutes; S44, taking the shape memory alloy sheet from step S43 out of the water, and measuring the spans at both ends of the shape memory alloy sheet; S45. If the spans of the shape memory alloy sheet at both ends are within the standard range, the shape memory alloy sheet meets the shape requirements, and the process goes to step S5. If the spans of the shape memory alloy sheet at both ends are not within the standard range, the shape memory alloy sheet does not meet the shape requirements, and the process goes to step S3.

[0010] Preferably, step S5 includes the following steps: Step S51, flattening the shape memory alloy sheet at room temperature; Step S52: Casting the composite solution along the length direction of the inwardly curved side of the shape memory alloy sheet, controlling the composite solution casting process by presetting the scraper height, and coating the composite solution on the outer surface of the shape memory alloy sheet to obtain a pre-treated sheet-type composite actuator; Step S53: The pre-processed chip-type composite driver is placed in a vacuum drying oven at 80° C. and stored at a constant temperature for 20 hours to obtain a first-stage chip-type composite driver; Step S54: The first-stage chip-type composite driver is removed from the glass slide and placed in a hot press for 1 hour to allow the composite solution to form a composite film layer on the shape memory alloy sheet, thereby obtaining a second-stage chip-type composite driver.

[0011] Preferably, the temperature of the upper and lower molds of the hot press in step S54 is set to 80° C., and the pressure of the upper and lower molds of the hot press in step S54 is 15 MPa.

[0012] Preferably, step S6 includes the following steps: Step S61: coating a conductive silver paste on a side of the composite film layer away from the shape memory alloy sheet; Step S62: After the second-stage chip-type composite driver is coated with conductive silver paste, it is dried in an oven at a constant temperature of 80°C for 2.5 hours to form a surface electrode layer on the side of the composite film layer away from the shape memory alloy sheet, thereby obtaining a third-stage chip-type composite driver.

[0013] The present application provides a sheet-type composite bending actuator that adopts the following technical solution: A sheet-type composite bending actuator comprises a shape memory alloy sheet, a composite film layer is arranged on the shape memory alloy sheet, a surface electrode layer is arranged on the composite film layer, and external guide wires are arranged on the side of the shape memory alloy sheet away from the composite film layer and on the side of the surface electrode layer away from the composite film layer.

[0014] By adopting the above technical solution, when high voltage is applied to the composite film layer, the dipole flips, the degree of order inside the composite film layer increases, the entropy value decreases and the temperature increases, and the shape memory alloy sheet is heated by heat conduction. Then, the shape memory alloy sheet undergoes a reverse phase transformation from martensite to austenite when heated, so that the shape memory alloy sheet bends and deforms; when the electric field is turned off, the degree of order inside the composite film layer decreases, the entropy value decreases and the temperature decreases, so that the shape memory alloy sheet cools down, and then the shape memory alloy sheet cools down and undergoes a phase transformation from austenite to martensite, so that the shape memory alloy sheet gradually returns to its initial state, completing a reciprocating drive process. Since the composite film layer has a reverse pyroelectric effect, and the reverse pyroelectric effect is highly efficient, the heating and cooling processes of the driver have shorter cycle periods compared to traditional current heating and natural cooling.

[0015] In summary, this application includes at least one of the following beneficial technical effects: 1. The composite film layer and the shape memory alloy sheet form a single flexible sheet structure, achieving electric-mechanical-thermal multi-field coupled actuation. On the one hand, the composite film layer, leveraging its inherent softness, can complete reciprocating deformation with the shape memory alloy sheet without falling off. On the other hand, the composite film layer's strong breakdown field and high dielectric constant enable it to exhibit a high inverse pyroelectric effect under an applied electric field. This inverse pyroelectric effect of the composite film layer stimulates the shape memory alloy sheet to complete the reciprocating deformation actuation process, resulting in shorter heating and cooling cycles for the actuator compared to traditional current heating and natural cooling. 2. In the process of preparing a composite solution by introducing the lead barium zirconate nanofibers into the polyvinylidene fluoride substrate, after the lead barium zirconate nanofibers are uniformly dispersed in the N,N-dimethoxyformamide suspension solution, the mixed solution is ultrasonically treated to reduce the agglomeration of the lead barium zirconate nanofibers, so that the lead barium zirconate nanofibers in the composite film layer are uniformly distributed, thereby improving the ferroelectric properties of the composite film layer; 3. During the aging training process of the shape memory alloy sheet, the shape memory alloy sheet forms a memory bending shape through repeated heating and cooling, thereby improving the stability of the shape memory alloy sheet in forming the memory bending shape; 4. During the process of forming the composite thin film layer on the shape memory alloy sheet, the first-stage chip-type composite actuator is hot-pressed to tightly bond the lead barium zirconate nanofibers to the shape memory alloy sheet, thereby reducing internal defects in the lead barium zirconate nanofibers and improving the ferroelectric properties of the composite thin film layer, allowing the chip-type composite bending actuator to be applied with a higher voltage. 5. During the preparation of the first configuration solution, lead acetate trihydrate was added to the first mixed solution so that the mass of lead in the first configuration solution was 1.2 times the mass of lead in the first mixed solution to compensate for the volatilization of lead during the annealing process of the 0.8 mol / L barium lead zirconate precursor nanofibers. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a cross-sectional view of a sheet-type composite bending actuator in Example 1 of the present application.

[0017] Figure 2 This is a flow chart of a process for preparing a sheet-type composite bending actuator in Example 2 of the present application.

[0018] Figure 3 This is a flow chart of a process for preparing a sheet-type composite bending actuator in Example 3 of the present application.

[0019] Figure 4 This is a schematic diagram comparing the voltage and displacement change trends in Example 4 of the present application.

[0020] Figure 5 This is a schematic diagram comparing displacement and time change trends in Example 4 of the present application.

[0021] Figure 6 This is a schematic diagram comparing the voltage and leakage current changing trends in Example 4 of the present application.

[0022] Figure 7 This is a performance comparison table of a sheet-type composite bending actuator and a shape memory alloy sheet actuator according to Example 4 of the present application.

[0023] Explanation of the accompanying symbols: 1. shape memory alloy sheet; 2. composite film layer; 3. surface electrode layer; 4. external guide wire. DETAILED DESCRIPTION

[0024] The following is combined with Figure 1-7 This application is described in further detail.

[0025] The present application embodiment 1 discloses a sheet-type composite bending actuator. Figure 1, comprising a shape memory alloy sheet 1, a composite film layer 2 provided on the shape memory alloy sheet 1, and a surface electrode layer 3 provided on the composite film layer 2. The side of the shape memory alloy sheet 1 away from the composite film layer 2 is the negative electrode side, and the side of the surface electrode layer 3 away from the composite film layer 2 is the positive electrode side. Both the positive and negative sides are electrically connected to an external guide wire 4. When high voltage is applied to the composite film layer 2, the dipole flips, the degree of order inside the composite film layer 2 increases, the entropy value decreases, and the temperature increases. The shape memory alloy sheet 1 is heated by heat conduction, and then the shape memory alloy sheet 1 undergoes a reverse phase transformation from martensite to austenite, thereby causing the shape memory alloy sheet 1 to bend and deform. When the electric field is turned off, the degree of order inside the composite film layer 2 decreases, the entropy value decreases, and the temperature decreases, thereby cooling the shape memory alloy sheet 1. Then, the shape memory alloy sheet 1 cools down and undergoes a phase transformation from austenite to martensite, causing the shape memory alloy sheet 1 to gradually return to its initial state, completing a reciprocating drive process. Since the composite film layer 2 has a reverse pyroelectric effect and the reverse pyroelectric effect is highly efficient, the heating and cooling processes of the driver have a shorter cycle period compared to traditional current heating and natural cooling.

[0026] Example 2 of the present application discloses a process for preparing a sheet-type composite bending actuator. Figure 2 , including the following steps.

[0027] Step S1, preparing lead barium zirconate nanofibers, includes the following steps.

[0028] In step S11, 2.913 g of lead acetate trihydrate and 0.409 g of barium acetate were dissolved in 1.59 ml of glacial acetic acid and 1.89 ml of deionized water, stirred at 60° C. for 30 min, and then cooled to room temperature to obtain a first mixed solution. Lead acetate trihydrate was then added to the first mixed solution to obtain a first configured solution, and the mass of lead element in the first configured solution was 1.2 times the mass of lead element in the first mixed solution. 3.743 g of zirconium n-propoxide solution was dissolved in 0.59 ml of 2-ethylene glycol methyl ether solution, and stirred at room temperature for 10 min to obtain a second mixed solution. 0.79 ml of acetylacetone was added to the second mixed solution, and stirred at room temperature for 30 min to obtain a second configured solution.

[0029] Step S12: Mix the first solution, the second solution, and 4.99 ml of deionized water, and stir at room temperature for 2 h to obtain a solution with a pH of 4.19.

[0030] Step S13: The mixed solution stirred for 2 hours in step S12 is allowed to stand and age for 24 hours.

[0031] Step S14: Filter the mixed solution after aging for 24 hours in step S13 using 0.2 μm filter paper.

[0032] Step S15: Mix 0.65 g of polyvinyl pyrrolidone with the mixed solution obtained by filtering in step S14, and stir at room temperature for 2 h.

[0033] Step S16: The mixed solution stirred for 2 hours in step S15 is jet-spun in a strong electric field to obtain a 0.8 mol / L lead barium zirconate nanoprecursor. The spinning voltage is 11 kV, the spinning current is 1.7 A, the distance from the spinning needle to the spinning collector is 8 cm, and the spinning rate is 0.7 ml / h.

[0034] Step S17: First, 0.8 mol / L of lead barium zirconate precursor nanofibers is placed in a sintering furnace. The sintering furnace is first raised from room temperature to 350°C at a rate of 3°C / min and then maintained at 350°C for 30 minutes to fully volatilize the solvent in the 0.8 mol / L lead barium zirconate precursor nanofibers. Then, the sintering furnace is raised from 350°C to 450°C at a rate of 5°C / min and then maintained at 450°C for 60 minutes to fully pyrolyze the lead barium zirconate precursor nanofibers. Finally, the sintering furnace is raised from 450°C to 750°C at a rate of 5°C / min and then maintained at a constant temperature for 3 hours to obtain lead barium zirconate nanofibers.

[0035] Step S2, introducing the lead barium zirconate nanofibers obtained in step S1 into a polyvinylidene fluoride substrate to prepare a composite solution, includes the following steps.

[0036] Step S21: At room temperature, 0.32 g of lead barium zirconate nanofibers are uniformly dispersed in 15 ml of N,N-dimethoxyformamide suspension solution and then ultrasonically treated for 0.5 h to 1.5 h.

[0037] Step S22: At room temperature, 3.00 g of polyvinylidene fluoride powder is slowly added to the solution after ultrasonic treatment in step S21.

[0038] Step S23: The solution mixed with the polyvinylidene fluoride powder in step S22 was magnetically stirred at room temperature for 19 hours, and then vacuum degassed for 30 minutes.

[0039] In step S24, the mixed solution after vacuum degassing for 30 minutes in step S23 is allowed to stand to obtain a composite solution.

[0040] Step S3, performing aging training on the shape memory alloy sheet to form a memory bending shape, includes the following steps.

[0041] Step S31: Fix the ends of the shape memory alloy sheet to the ends of the mold to bend the shape memory alloy sheet. The shape memory alloy sheet has a nickel atomic content of ≥50 at%, a length of 80 mm to 120 mm, a width of 3 mm to 9 mm, and a height of 0.1 mm to 0.5 mm.

[0042] Step S32: After placing the shape memory alloy sheet and the mold in step S31 in a heating furnace, the temperature of the heating furnace is raised from 20° C. to 450° C. within 40 minutes, and then the shape memory alloy sheet and the mold are kept in the heating furnace at 450° C. for 1 hour.

[0043] Step S33: quickly take the shape memory alloy sheet and the mold in step S32 out of the heating furnace and place them in 20° C. water to cool for 3 minutes.

[0044] Step S34: First, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S33 in a 450°C heating furnace for constant temperature treatment for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20°C water for cooling for 3 minutes.

[0045] Step S35: First, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S34 in a 450°C heating furnace for constant temperature treatment for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20°C water for cooling for 3 minutes.

[0046] Step S36: First, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S35 in a 450°C heating furnace for constant temperature treatment for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20°C water for cooling for 3 minutes.

[0047] Step S37: First, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S36 in a 450°C heating furnace for constant temperature treatment for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20°C water for cooling for 3 minutes.

[0048] Step S4, selecting a shape memory alloy sheet that meets the shape requirements, includes the following steps.

[0049] S41. Remove the shape memory alloy sheet from the mold.

[0050] S42. Flatten or twist the shape memory alloy sheet into any shape using external force.

[0051] S43, placing the shape memory alloy sheet in step S42 in 80°C water for 5 minutes.

[0052] S44, taking the shape memory alloy sheet in step S43 out of the water, and measuring the spans at both ends of the shape memory alloy sheet.

[0053] S45. If the spans of the shape memory alloy sheet at both ends are within the standard range, the shape memory alloy sheet meets the shape requirements, and the process goes to step S5. If the spans of the shape memory alloy sheet at both ends are not within the standard range, the shape memory alloy sheet does not meet the shape requirements, and the process goes to step S3.

[0054] Step S5, forming a composite thin film layer on the shape memory alloy sheet having the shape requirements met in step S4 using the composite solution prepared in step S2, includes the following steps.

[0055] Step S51 : Fixing both ends of the shape memory alloy sheet on a glass slide at room temperature to flatten the shape memory alloy sheet.

[0056] Step S52: Casting the composite solution along the length direction on the inwardly curved side of the shape memory alloy sheet, controlling the composite solution casting process by presetting the scraper height, and coating the composite solution on the outer surface of the shape memory alloy sheet to obtain a pre-treated sheet-type composite actuator.

[0057] Step S53: Pre-processing the chip-type composite driver by placing it in a vacuum drying oven at 80° C. and preserving it at a constant temperature for 20 hours to obtain a first-stage chip-type composite driver.

[0058] Step S54: The first-stage chip-type composite actuator is removed from the glass slide and placed in a hot press for 1 hour to form a composite film layer on the shape memory alloy sheet. The second-stage chip-type composite actuator is obtained. The upper and lower mold temperatures of the hot press are both set to 80°C, and the upper and lower mold pressures are 15 MPa.

[0059] Step S6, forming a surface electrode layer on the composite film layer, includes the following steps.

[0060] Step S61: coating a conductive silver paste on a side of the composite film layer away from the shape memory alloy sheet.

[0061] Step S62: After the second-stage chip-type composite driver is coated with conductive silver paste, it is dried in an oven at a constant temperature of 80°C for 2.5 hours to form a surface electrode layer on the side of the composite film layer away from the shape memory alloy sheet, thereby obtaining a third-stage chip-type composite driver.

[0062] Step S7: connecting external guide wires to the side of the shape memory alloy sheet away from the composite film layer and the side of the surface electrode layer away from the composite film layer to obtain a chip-type composite driver.

[0063] Example 3 of the present application discloses a process for preparing a sheet-type composite bending actuator. Figure 3 , including the following steps.

[0064] Step S1, preparing lead barium zirconate nanofibers, includes the following steps.

[0065] In step S11, 2.913 g of lead acetate trihydrate and 0.409 g of barium acetate were dissolved in 1.59 ml of glacial acetic acid and 1.89 ml of deionized water, stirred at 60° C. for 30 min, and then cooled to room temperature to obtain a first mixed solution. Lead acetate trihydrate was then added to the first mixed solution to obtain a first configured solution, and the mass of lead element in the first configured solution was 1.2 times the mass of lead element in the first mixed solution. 3.743 g of zirconium n-propoxide solution was dissolved in 0.59 ml of 2-ethylene glycol methyl ether solution, and stirred at room temperature for 10 min to obtain a second mixed solution. 0.79 ml of acetylacetone was added to the second mixed solution, and stirred at room temperature for 30 min to obtain a second configured solution.

[0066] Step S12: Mix the first solution, the second solution, and 4.99 ml of deionized water, and stir at room temperature for 2 h to obtain a solution with a pH of 4.19.

[0067] Step S13: The mixed solution stirred for 2 hours in step S12 is allowed to stand and age for 24 hours.

[0068] Step S14: Filter the mixed solution after aging for 24 hours in step S13 using 0.2 μm filter paper.

[0069] Step S15: Mix 0.65 g of polyvinyl pyrrolidone with the mixed solution obtained by filtering in step S14, and stir at room temperature for 2 h.

[0070] Step S16: The mixed solution stirred for 2 hours in step S15 is jet-spun in a strong electric field to obtain a 0.8 mol / L lead barium zirconate nanoprecursor. The spinning voltage is 11 kV, the spinning current is 1.7 A, the distance from the spinning needle to the spinning collector is 8 cm, and the spinning rate is 0.7 ml / h.

[0071] Step S17: First, 0.8 mol / L of lead barium zirconate precursor nanofibers is placed in a sintering furnace. The sintering furnace is first raised from room temperature to 350°C at a rate of 3°C / min and then kept at 350°C for 30 minutes to fully volatilize the solvent in the 0.8 mol / L lead barium zirconate precursor nanofibers. Then, the sintering furnace is raised from 350°C to 450°C at a rate of 5°C / min and then kept at 450°C for 60 minutes to fully pyrolyze the lead barium zirconate precursor nanofibers. Finally, the sintering furnace is raised from 450°C to 750°C at a rate of 5°C / min and then kept at a constant temperature for 3 hours to obtain lead barium zirconate nanofibers. The diameter of the lead barium zirconate nanofibers is about 240 nm, and the length of the lead barium zirconate nanofibers is about 700 nm. Lead barium zirconate nanofibers are mainly composed of four elements: lead, barium, zirconium and oxygen, with the atomic percentage of lead being 15.66%, the atomic percentage of barium being 4.02%, the atomic percentage of zirconium being 28.94% and the atomic percentage of oxygen being 58.54%.

[0072] Step S2, introducing the lead barium zirconate nanofibers obtained in step S1 into a polyvinylidene fluoride substrate to prepare a composite solution, includes the following steps.

[0073] Step S21: At room temperature, 0.32 g of barium lead zirconate nanofibers were uniformly dispersed in 15 ml of N,N-dimethoxyformamide suspension solution and then ultrasonically treated for 1 hour.

[0074] Step S22: At room temperature, 3.00 g of polyvinylidene fluoride powder is slowly added to the solution after ultrasonic treatment in step S21.

[0075] Step S23: The solution mixed with the polyvinylidene fluoride powder in step S22 was magnetically stirred at room temperature for 19 hours, and then vacuum degassed for 30 minutes.

[0076] In step S24, the mixed solution after vacuum degassing for 30 minutes in step S23 is allowed to stand to obtain a composite solution.

[0077] Step S3, performing aging training on the shape memory alloy sheet to form a memory bending shape, includes the following steps.

[0078] Step S31: Fix the ends of the shape memory alloy sheet to the ends of the mold to bend the shape memory alloy sheet. The arch span at the ends of the shape memory alloy sheet is 4 cm. The nickel atomic content of the shape memory alloy sheet is 55.45 at%, and the shape memory alloy sheet is 100 mm long, 6 mm wide, and 0.3 mm high.

[0079] Step S32: After placing the shape memory alloy sheet and the mold in step S31 in a muffle furnace, the temperature of the muffle furnace is raised from 20° C. to 450° C. within 40 minutes, and then the shape memory alloy sheet and the mold are kept in the muffle furnace at 450° C. for 1 hour.

[0080] Step S33: quickly take out the shape memory alloy sheet and the mold from step S32 from the muffle furnace and place them in 20° C. water to cool for 3 minutes.

[0081] Step S34: First, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S33 in a 450°C heating furnace for constant temperature treatment for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20°C water for cooling for 3 minutes.

[0082] Step S35: First, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S34 in a 450°C heating furnace for constant temperature treatment for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20°C water for cooling for 3 minutes.

[0083] Step S36: First, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S35 in a 450°C heating furnace for constant temperature treatment for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20°C water for cooling for 3 minutes.

[0084] Step S37: First, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S36 in a 450°C heating furnace for constant temperature treatment for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20°C water for cooling for 3 minutes.

[0085] Step S4, selecting a shape memory alloy sheet that meets the shape requirements, includes the following steps.

[0086] S41. Remove the shape memory alloy sheet from the mold.

[0087] S42. Flatten or twist the shape memory alloy sheet into any shape using external force.

[0088] S43, placing the shape memory alloy sheet in step S42 in 80°C water for 5 minutes.

[0089] S44, taking the shape memory alloy sheet in step S43 out of the water, and measuring the spans at both ends of the shape memory alloy sheet.

[0090] S45. If the span between the beginning and the end of the shape memory alloy sheet does not exceed 7 cm, the shape memory alloy sheet meets the shape requirements, and step S5 is performed; if the span between the beginning and the end of the shape memory alloy sheet exceeds 7 cm, the shape memory alloy sheet does not meet the shape requirements, and step S3 is performed.

[0091] Step S5, forming a composite thin film layer on the shape memory alloy sheet having the shape requirements met in step S4 using the composite solution prepared in step S2, includes the following steps.

[0092] Step S51 : Fixing both ends of the shape memory alloy sheet on a glass slide at room temperature to flatten the shape memory alloy sheet.

[0093] Step S52: Casting the composite solution along the length direction on the inwardly curved side of the shape memory alloy sheet, controlling the composite solution casting process by presetting the scraper height, and coating the composite solution on the outer surface of the shape memory alloy sheet to obtain a pre-treated sheet-type composite actuator.

[0094] Step S53: Pre-processing the chip-type composite driver by placing it in a vacuum drying oven at 80° C. and preserving it at a constant temperature for 20 hours to obtain a first-stage chip-type composite driver.

[0095] Step S54: The first-stage chip-type composite actuator is removed from the glass slide and placed in a hot press for 1 hour to form a composite film layer on the shape memory alloy sheet. The second-stage chip-type composite actuator is obtained. The upper and lower mold temperatures of the hot press are both set to 80°C, and the upper and lower mold pressures are 15 MPa.

[0096] Step S6, forming a surface electrode layer on the composite film layer, includes the following steps.

[0097] Step S61: coating a conductive silver paste on a side of the composite film layer away from the shape memory alloy sheet.

[0098] Step S62: After the second-stage chip-type composite driver is coated with conductive silver paste, it is dried in an oven at a constant temperature of 80°C for 2.5 hours to form a surface electrode layer on the side of the composite film layer away from the shape memory alloy sheet, thereby obtaining a third-stage chip-type composite driver.

[0099] Step S7: connecting external guide wires to the side of the shape memory alloy sheet away from the composite film layer and the side of the surface electrode layer away from the composite film layer to obtain a chip-type composite driver.

[0100] Example 4 of the present application discloses a driver testing process. Figures 4 to 7The driver is fixed to an insulating bracket. A DC power supply provides a high DC voltage to the driver and displays the leakage current in real time. A laser displacement sensor monitors the driver's position changes and transmits them to the industrial computer. When high voltage is applied to the sheet-type composite bending driver, the composite film layer heats up, causing the shape memory alloy sheet to bend and deform due to the heat, and the distance difference between the end of the shape memory alloy sheet and the laser displacement sensor increases. When the electric field is removed, the composite film layer cools down, and some of the heat from the shape memory alloy sheet is absorbed and carried away by the composite film layer. The remaining heat is cooled by natural heat dissipation. As the applied voltage increases, the displacement change of the sheet-type composite bending driver gradually increases.

[0101] refer to Figure 4 and Figure 5 When the applied voltage was 0.00kV, the chip-type composite bending actuator showed no significant fluctuations throughout the test time. When the applied voltages were 0.43kV and 0.72kV, the displacement changes of the chip-type composite bending actuator were similar throughout the test time. When the same voltage was applied to the chip-type composite bending actuator multiple times, the output displacement of the chip-type composite bending actuator remained essentially consistent.

[0102] refer to Figure 6 When the applied voltage increases, the corresponding leakage current increases. However, the leakage current value is at the microampere (μA) level, so the impact of Joule heating during the driving process of the chip-type composite bending actuator is relatively small.

[0103] refer to Figure 7 By applying different currents to the shape memory alloy sheet bending actuator, the output displacement, heating time, and cooling time of the shape memory alloy sheet were obtained. By applying different voltages to the sheet-type composite bending actuator, the output displacement, heating time, and cooling time of the sheet-type composite bending actuator were also obtained. It can be seen that when the output displacement is similar, the cooling time of the sheet-type composite bending actuator is shorter than that of the shape memory alloy sheet bending actuator, thereby reducing the actuator response time and shortening the actuator cycle.

[0104] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A process for preparing a sheet-type composite bending actuator, characterized by: The following steps are involved: Step S1, preparing lead barium zirconate nanofibers; Step S2, introducing the lead barium zirconate nanofibers obtained in step S1 into a polyvinylidene fluoride substrate to prepare a composite solution; Step S3: performing aging training on the shape memory alloy sheet to form a memory bending shape; Step S4, selecting a shape memory alloy sheet that meets the shape requirements; Step S5, forming a composite thin film layer on the shape memory alloy sheet that meets the shape requirements in step S4 using the composite solution prepared in step S2; Step S6, forming a surface electrode layer on the composite film layer; Step S7: connecting external guide wires to the side of the shape memory alloy sheet away from the composite film layer and the side of the surface electrode layer away from the composite film layer to obtain a chip-type composite driver.

2. The process for preparing a sheet-type composite bending actuator according to claim 1, characterized in that: The step S1 comprises the following steps: Step S11: 2.913 g of lead acetate trihydrate and 0.409 g of barium acetate were dissolved in 1.59 ml of glacial acetic acid and 1.89 ml of deionized water, stirred at 60° C. for 30 min, and then cooled to room temperature to obtain a first mixed solution. Lead acetate trihydrate was then added to the first mixed solution to obtain a first configured solution, wherein the mass of lead element in the first configured solution was 1.2 times the mass of lead element in the first mixed solution. 3.743 g of zirconium n-propoxide solution was dissolved in 0.59 ml of 2-ethylene glycol methyl ether solution, stirred at room temperature for 10 min to obtain a second mixed solution. 0.79 ml of acetylacetone was added to the second mixed solution, and stirred at room temperature for 30 min to obtain a second configured solution. Step S12: Mix the first solution, the second solution, and 4.99 ml of deionized water, and stir at room temperature for 2 hours; Step S13, the mixed solution after stirring for 2 hours in step S12 is allowed to stand and age for 24 hours; Step S14: filtering the mixed solution after aging for 24 hours in step S13 using 0.2 μm filter paper; Step S15, mixing 0.65 g of polyvinyl pyrrolidone with the mixed solution obtained by filtering in step S14, and stirring at room temperature for 2 h; Step S16: jet-spinning the mixed solution stirred for 2 h in step S15 in a strong electric field to obtain a lead barium zirconate nanoprecursor with a concentration of 0.8 mol / L, wherein the spinning voltage is 11 kV, the spinning current is 1.7 A, the distance from the spinning needle to the spinning collector is 8 cm, and the spinning rate is 0.7 ml / h; Step S17, placing 0.8 mol / L of lead barium zirconate precursor nanofibers in a sintering furnace, first raising the sintering furnace temperature from room temperature to 350°C at a rate of 3°C / min and then keeping it at 350°C for 30 minutes, then raising the sintering furnace temperature from 350°C to 450°C at a rate of 5°C / min and then keeping it at 450°C for 60 minutes, and finally raising the sintering furnace temperature from 450°C to 750°C at a rate of 5°C / min and keeping it at a constant temperature for 3 hours to obtain lead barium zirconate nanofibers.

3. The process for preparing a sheet-type composite bending actuator according to claim 1, characterized in that: The step S2 comprises the following steps: Step S21: at room temperature, 0.32 g of lead barium zirconate nanofibers were uniformly dispersed in 15 ml of N,N-dimethoxyformamide suspension solution and then ultrasonically treated for 0.5 h to 1.5 h; Step S22: at room temperature, slowly add 3.00 g of polyvinylidene fluoride powder into the solution after ultrasonic treatment in step S21; Step S23, the solution mixed with polyvinylidene fluoride powder in step S22 is magnetically stirred at room temperature for 19 hours, and then vacuum degassed for 30 minutes; In step S24, the mixed solution after vacuum degassing for 30 minutes in step S23 is allowed to stand to obtain a composite solution.

4. The process for preparing a sheet-type composite bending actuator according to claim 1, characterized in that: The step S3 comprises the following steps: Step S31, fixing the ends of a shape memory alloy sheet to the ends of a mold to bend the shape memory alloy sheet, wherein the nickel atomic content of the shape memory alloy sheet is ≥50 at%, the length of the shape memory alloy sheet is between 80 mm and 120 mm, the width of the shape memory alloy sheet is between 3 mm and 9 mm, and the height of the shape memory alloy sheet is between 0.1 mm and 0.5 mm; Step S32: After placing the shape memory alloy sheet and the mold in step S31 in a heating furnace, the temperature of the heating furnace is raised from 20° C. to 450° C. within 40 minutes, and then the shape memory alloy sheet and the mold are kept in the heating furnace at 450° C. for 1 hour; Step S33: quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20° C. water to cool for 3 minutes; Step S34: first, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S33 in a 450° C. heating furnace for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20° C. water for cooling for 3 minutes; Step S35: first, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S34 in a 450° C. heating furnace for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20° C. water for cooling for 3 minutes; Step S36: first, place the shape memory alloy sheet and the mold that have been cooled for 3 minutes in step S35 in a 450° C. heating furnace for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20° C. water for cooling for 3 minutes; Step S37: First, place the shape memory alloy sheet and the mold cooled for 3 minutes in step S36 in a 450°C heating furnace for constant temperature treatment for 15 minutes, then quickly remove the shape memory alloy sheet and the mold from the heating furnace and place them in 20°C water for cooling for 3 minutes.

5. The process for preparing a sheet-type composite bending actuator according to claim 1, characterized in that: The step S4 comprises the following steps: S41, removing the shape memory alloy sheet from the mold; S42, flattening or twisting the shape memory alloy sheet into any shape by applying an external force; S43, placing the shape memory alloy sheet in step S42 in 80°C water for 5 minutes; S44, taking the shape memory alloy sheet from step S43 out of the water, and measuring the spans at both ends of the shape memory alloy sheet; S45. If the spans of the shape memory alloy sheet at both ends are within the standard range, the shape memory alloy sheet meets the shape requirements, and the process goes to step S5. If the spans of the shape memory alloy sheet at both ends are not within the standard range, the shape memory alloy sheet does not meet the shape requirements, and the process goes to step S3.

6. The process for preparing a sheet-type composite bending actuator according to claim 1, characterized in that: The step S5 comprises the following steps: Step S51, flattening the shape memory alloy sheet at room temperature; Step S52: Casting the composite solution along the length direction of the inwardly curved side of the shape memory alloy sheet, controlling the composite solution casting process by presetting the scraper height, and coating the composite solution on the outer surface of the shape memory alloy sheet to obtain a pre-treated sheet-type composite actuator; Step S53: The pre-processed chip-type composite driver is placed in a vacuum drying oven at 80° C. and stored at a constant temperature for 20 hours to obtain a first-stage chip-type composite driver; Step S54: The first-stage chip-type composite driver is removed from the glass slide and placed in a hot press for 1 hour to allow the composite solution to form a composite film layer on the shape memory alloy sheet, thereby obtaining a second-stage chip-type composite driver.

7. The process for preparing a sheet-type composite bending actuator according to claim 6, characterized in that: The temperature of the upper and lower molds of the hot press in step S54 is set to 80° C., and the pressure of the upper and lower molds of the hot press in step S54 is 15 MPa.

8. The process for preparing a sheet-type composite bending actuator according to claim 6, characterized in that: The step S6 comprises the following steps: Step S61: coating a conductive silver paste on a side of the composite film layer away from the shape memory alloy sheet; Step S62: After the second-stage chip-type composite driver is coated with conductive silver paste, it is dried in an oven at a constant temperature of 80°C for 2.5 hours to form a surface electrode layer on the side of the composite film layer away from the shape memory alloy sheet, thereby obtaining a third-stage chip-type composite driver.

9. A sheet-type composite bending actuator produced according to the process for producing a sheet-type composite bending actuator according to any one of claims 1 to 8, comprising a shape memory alloy sheet, characterized in that: A composite film layer is arranged on the shape memory alloy sheet, a surface electrode layer is arranged on the composite film layer, and external guide wires are arranged on both the side of the shape memory alloy sheet away from the composite film layer and the side of the surface electrode layer away from the composite film layer.

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