A method for preparing a stacked supermagnetostrictive material

Abstract

This invention relates to a method for preparing a stacked supermagnetic-strictive material. The stacked supermagnetic-strictive material comprises alternately stacked supermagnetic-strictive rod slices and insulating sheets, with adjacent supermagnetic-strictive rod slices and insulating sheets bonded together by a phenolic resin layer. First, phenolic resin particles are sprayed onto the surface of the insulating sheet using an electrostatic spraying method, forming a phenolic resin particle layer on the surface of the insulating sheet. Then, the supermagnetic-strictive rod slices and the insulating sheets with the phenolic resin particle layer are alternately stacked to obtain a pre-fabricated stack. The pre-fabricated stack is then fixed, cured, and cooled to obtain the stacked supermagnetic-strictive material. This preparation method ensures consistent spacing between the supermagnetic-strictive rod slices and insulating sheets, effectively solving the problems of uneven adhesive layer thickness, easy displacement of insulating sheets, low efficiency, and poor product consistency in existing technologies.

Description

Technical Field

[0001] This invention relates to a method for preparing a layered super magnetostrictive material, belonging to the field of magnetostrictive material processing technology. Background Technology

[0002] Due to their high magnetostriction coefficient and excellent electromechanical conversion performance, super magnetostrictive materials (such as Terfenol-D) are widely used in underwater acoustic transducers, precision actuators and other equipment, which need to withstand alternating magnetic fields during operation.

[0003] According to Maxwell's electromagnetic theory, when a giant magnetostrictive material is in operation, closed-loop eddy currents form inside the material. For example, when Terfenol-D rods are used in underwater acoustic transducers, and the transducer operates at frequencies from 1 kHz to 5 kHz, the temperature of the Terfenol-D rods rises rapidly. This causes eddy current losses to account for more than 35% of the total energy consumption, resulting in a temperature rise rate of 8-12 °C / min. The temperature rise effect caused by eddy current losses is significantly harmful: firstly, the magnetostriction coefficient of Terfenol-D rods decreases non-linearly with increasing temperature. When the temperature exceeds 80 °C, the magnetostriction coefficient value can decrease by more than 40%, directly causing a 5-8 dB drop in the transmit voltage response of the underwater acoustic transducer; secondly, grain boundary slip induced by thermal stress shortens the fatigue life of Terfenol-D rods to less than 500 hours, far below the service life requirements of underwater acoustic equipment.

[0004] To block eddy current paths, the industry commonly uses wire electrical discharge machining to process periodically interlaced micron-sized gaps in the axial direction of the giant magnetostrictive rod, and then fills the micron-sized gaps with epoxy resin. However, during use, the interlaced cuts can easily lead to stress concentration in the rod, resulting in a decrease in the rod's bending strength and fracture toughness, which affects the use of the rod.

[0005] To reduce eddy current heating during the use of magnetostrictive rods, while improving their bending strength and fracture toughness and extending their service life, modern industry typically slices and bonds magnetostrictive rods to form multi-layered structures, creating stacked magnetostrictive materials. In multi-layered structures, it is often necessary to slice the magnetostrictive rods, place insulating sheets between the slices, and then bond the slices and insulating sheets together to achieve electrical isolation and mechanical connection. A common assembly and bonding method involves manually coating the slices with liquid phenolic resin, then placing insulating sheets such as mica sheets, followed by heating and curing. This process is repeated until the desired number of layers is obtained. This method is simple and requires low equipment investment, but the thickness of the manually applied adhesive layer is often uneven, prone to bubbles, and inefficient, resulting in poor product consistency. It is only suitable for small-batch production or trial production. It is evident that existing processes, due to the difficulty in precisely controlling the amount of adhesive applied and the coating pressure, are prone to causing local adhesive layers to be too thick or too thin, directly affecting the consistency of interlayer spacing. At the same time, during the heating and curing process after adhesive application, the adhesive liquid in a flowing state can easily cause micro-displacement of the insulating sheet, thereby causing differences in interlayer thickness and sheet skew, affecting the overall strain consistency and acoustic properties.

[0006] In another common multilayer stacked structure, the slices are electrically isolated and mechanically connected through an adhesive layer. A common assembly and bonding method involves first fixing the slices and controlling the gaps between them, then pouring liquid adhesive into the gaps and allowing it to cure. For example, Chinese invention patent CN101388433B discloses a method for preparing a bonded magnetostrictive material, which includes the following steps: a) processing a directionally solidified magnetostrictive rod into magnetostrictive sheets with a thickness of 1-15 mm; b) fixing the magnetostrictive sheets, leaving a gap of 0.05-1 mm between the sheets; c) pouring liquid adhesive (a uniformly mixed mixture of liquid phenolic resin and its curing agent in a certain proportion) into the gaps between the magnetostrictive sheets, allowing the adhesive to cure, and obtaining the bonded magnetostrictive material. This method requires specialized molds with high dimensional accuracy, and the liquid adhesive may not completely wet the gaps, leading to high manufacturing costs and potentially low product quality. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing a stacked super magnetostrictive material, so as to improve the product quality of the stacked super magnetostrictive material.

[0008] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0009] A method for preparing a stacked supermagnetic-strictive material, wherein the stacked supermagnetic-strictive material comprises alternately stacked supermagnetic-strictive rod slices and insulating sheets, and adjacent supermagnetic-strictive rod slices and insulating sheets are bonded together by a phenolic resin layer; the preparation method includes the following steps:

[0010] S1. Phenolic resin particles are sprayed onto the surface of the insulating sheet by electrostatic spraying, so that a phenolic resin particle layer is formed on the surface of the insulating sheet.

[0011] Among them, the surface of the insulating sheet is the surface of the insulating sheet and the sliced ​​super magnetostrictive rod in the stacked super magnetostrictive material;

[0012] S2. Alternately stack super magnetostrictive rod slices and insulating sheets with phenolic resin particle layers to obtain a prefabricated stack;

[0013] S3. After fixing the prefabricated stack, heat at 100-115℃ for 20-40 min, then at 120-150℃ for 20-60 min, and then at 160-190℃ for 40-80 min. After cooling, a layered super magnetostrictive material is obtained.

[0014] Therefore, by electrostatic spraying and baking, a uniform phenolic resin particle layer (composed of numerous phenolic resin particles uniformly distributed on the surface of the insulating sheet) can be formed on the surface of the insulating sheet. This helps ensure the consistency of the spacing between the magnetostrictive rod slices and the insulating sheet in the final product, laying the foundation for the formation of a uniformly thick phenolic resin layer between adjacent magnetostrictive rod slices and insulating sheets. Then, by alternately stacking the magnetostrictive rod slices and the insulating sheets with the phenolic resin particle layer, the target prefabricated stack can be obtained. After fixing the prefabricated stack, gradient heating is performed, allowing the phenolic resin particle layer to sequentially soften, melt, spread, and solidify the solid phenolic resin particles under various temperature conditions, thus obtaining the laminated magnetostrictive material. The assembly of the prefabricated stack does not involve liquid adhesive, and the phenolic resin particle layer has a certain roughness. Therefore, during the assembly and transportation of the prefabricated stack, the magnetostrictive rod slices and the insulating sheets are not prone to relative sliding, which helps ensure the final quality of the laminated magnetostrictive material, such as overall strain consistency.

[0015] In this invention, a gradient heating process is adopted. First, heating is carried out at 100-115℃ for 20-40 minutes to soften the phenolic resin particle layer and initially wet the interface between the super magnetostrictive rod slice and the insulating sheet. Then, heating is carried out at 120-150℃ for 20-60 minutes to fully melt the phenolic resin particle layer and promote the full flow of the molten adhesive to fill the gap between the super magnetostrictive rod slice and the insulating sheet. Finally, heating is carried out at 160-190℃ for 40-80 minutes to completely solidify the molten adhesive, forming a high-strength, uniform bonding interface, and forming a phenolic resin layer between the super magnetostrictive rod slice and the insulating sheet.

[0016] Furthermore, the average particle size of the phenolic resin particles is 20-60 μm, and even further, 25-40 μm.

[0017] Further, the softening point of the phenolic resin is 98-115℃, and the curing temperature is ≥150℃. Optionally, the flow rate of the phenolic resin is 35-55mm / 125℃. Even further, the phenolic resin is 2123 phenolic resin.

[0018] Furthermore, the insulating sheet is a mica sheet.

[0019] Furthermore, before S1, the insulating sheet is ultrasonically cleaned with anhydrous ethanol, dried, and ready for use.

[0020] Furthermore, in S1, during electrostatic spraying, the spraying pressure is controlled at 0.08-0.12 MPa, the spraying direction of the spray gun is perpendicular to the surface of the insulating sheet, the distance between the spray gun and the insulating sheet is 10-20 cm, or more specifically 12-18 cm, and the moving speed of the spray gun is 5-15 mm / s, or more specifically 8-12 mm / s. Optionally, the voltage for electrostatic spraying is 50-70 kV.

[0021] Furthermore, during electrostatic spraying, the spray gun is moved back and forth along the length of the insulating sheet for 2-4 rounds of spraying; during each 3-6 seconds of spraying, the spray gun is stopped and spraying is paused for 3-6 seconds; after one surface of the insulating sheet is sprayed, the insulating sheet is rotated so that the other surface of the insulating sheet faces the spray gun, and the same operation is performed.

[0022] Alternatively, the magnetostrictive rod is a magnetostrictive alloy cylindrical rod (e.g., Terfenol-D) with a diameter of 10-50 mm (further 15-40 mm).

[0023] Furthermore, before slicing, the supermagnetostrictive rod is annealed to release internal residual stress and prevent cracks from forming during subsequent processing. Optionally, the annealing temperature is 900-1100℃, held at that temperature for 1-4 hours in a protective atmosphere (such as argon), and then cooled in the furnace.

[0024] Optionally, during slicing, the annealed supermagnetostrictive alloy cylindrical rod is fixed on the fixture of a diamond multi-wire cutting machine, and cut using electroplated diamond steel wire with a diameter of 0.12-0.20 mm. The wire feed speed is 0.1-0.5 mm / min.

[0025] Furthermore, in S2, when assembling the prefabricated stack, a fixture is used for positioning to better align the layers and avoid misalignment between layers during the heating and curing process.

[0026] Further, in S3, after the prefabricated stack is fixed, it is heated at 105-110℃ for 25-35 minutes, then at 125-145℃ for 30-50 minutes, and then at 165-185℃ for 50-70 minutes.

[0027] Further, in S3, the prefabricated stack is fixed with a clamp; wherein the clamp includes a frame with openings at the top and bottom, and a clamping body is provided inside the frame. The clamping body includes a first clamping body and a second clamping body arranged opposite to each other. The first clamping body has a first recess on the side facing the second clamping body, and the second clamping body has a second recess on the side facing the first clamping body. When the first clamping body and the second clamping body are closed, they form a clamping body, and the first recess and the second recess combine to form a space for clamping the prefabricated stack. The frame is provided with a first bolt and a second bolt that are perpendicular to each other. The first bolt and the second bolt are both threaded to the frame. Blind holes are provided on the side of the first clamping body away from the first recess and the side of the second clamping body away from the second recess. The blind holes are provided with internal threads. When the prefabricated stack is in a fixed state, the first bolt passes through the frame and is threaded to the clamping body through the blind hole, and the second bolt passes through the frame and abuts against the clamping body. Therefore, the first bolt and frame assembly restrict the clamp's vertical and horizontal degrees of freedom, while the second bolt and frame assembly restricts its longitudinal degrees of freedom, enabling the clamp to stably fix the prefabricated stacked bodies. Simultaneously, the shape and size of the first and second recesses can be customized according to the dimensions and shape of the prefabricated stacked bodies to be clamped, thus enhancing the clamp's applicability.

[0028] Furthermore, the thickness of the giant magnetostrictive rod slices is 1.5-6.0 mm, and the thickness of the insulating sheet is 80-100 μm. The specific slice thickness can be determined based on the operating frequency required for the application of the laminated giant magnetostrictive material. Controlling the thickness of the giant magnetostrictive rod slices to 1.5-6.0 mm helps to suppress eddy current heating while ensuring that the mechanical strength of the laminated giant magnetostrictive material meets application requirements.

[0029] Optionally, the process also includes a finishing step on the stacked magnetostrictive material. Optionally, the outer diameter of the stacked magnetostrictive material is finished using a centerless grinder to eliminate minor misalignments caused by the bonding of the prefabricated stacks, ensuring overall roundness and surface roughness (Ra≤0.8μm); the ends of the stacked magnetostrictive material are corrected using a surface grinder, during which the stacked magnetostrictive material is fixed using a vacuum jig or a non-magnetic jig to prevent magnetization interference; the grinding depth is ≤0.01mm / time, gradually machining to a flatness of ≤0.01mm, ensuring end face parallelism and smoothness.

[0030] Optionally, in the stacked super magnetostrictive material, the spacing between adjacent super magnetostrictive rod slices and insulating sheets is less than 0.2 mm, the bonding strength is ≥20 MPa, and the insulation resistance is ≥100 MΩ.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] (1) The present invention can ensure the consistency of the spacing between the super magnetostrictive rod slices and the insulating sheet by simply fixing and limiting the prefabricated stacked body, which helps to achieve efficient mass production and can effectively solve the problems of uneven thickness of the adhesive layer (such as phenolic resin layer), easy displacement of the insulating sheet, low efficiency and poor product consistency in the prior art.

[0033] (2) By pre-coating the surface of the insulating sheet with phenolic resin particles by electrostatic spraying, the present invention can avoid the problems of uneven thickness and overflow caused by manual brushing of adhesive.

[0034] (3) The insulating sheet with phenolic resin particles of the present invention has no fluidity at room temperature, making subsequent assembly simpler and more convenient; the gradient heating system can avoid displacement of the insulating sheet in the early stage of curing, which helps to improve assembly accuracy.

[0035] (4) The phenolic resin particle layer of the present invention fully fills the micro gaps during the curing process, which helps to form a high-strength adhesive layer and significantly improves the shear resistance of the laminated super magnetostrictive material.

[0036] (5) By combining electrostatic spraying, fixing and gradient heating, the present invention can effectively ensure the consistency of the spacing between the supermagnetic-strict rod slices and the insulating sheet of the stacked supermagnetic-strict material, which helps the obtained stacked supermagnetic-strict material to exhibit better performance in terms of electrical insulation performance, resonant frequency consistency and acoustic output stability.

[0037] (6) The preparation method of the present invention does not require the use of hot pressing equipment or complex dispensing system, is suitable for mass production, has low manufacturing cost, and helps to promote its application. Attached Figure Description

[0038] Figure 1 This is a flowchart of a method for preparing a layered supermagnetostrictive material according to the present invention.

[0039] Figure 2 This is a perspective view of a clamp according to the present invention.

[0040] Figure 3 This is a cross-sectional view of a clamp according to the present invention.

[0041] Figure 4 This is a physical image of the finished laminated supermagnetostrictive material according to Embodiment 1 of the present invention. Detailed Implementation

[0042] The present invention will be described in detail below with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other. For ease of description, the words "upper," "lower," "left," and "right" appearing below only indicate that they are consistent with the upper, lower, left, and right directions of the drawings themselves, and do not limit the structure.

[0043] Example 1

[0044] See Figure 1 A method for preparing a stacked supermagnetic-strictive material, wherein the stacked supermagnetic-strictive material comprises alternately stacked supermagnetic-strictive rod slices and insulating sheets, and adjacent supermagnetic-strictive rod slices and insulating sheets are bonded together by a phenolic resin layer; the preparation method includes the following steps:

[0045] S1. Select a 30mm diameter supermagnetic-strictive alloy cylindrical rod (Terfenol-D) and run it under a vacuum of 5×10⁻⁶. - 3 Pa is heated to 1000℃, held for 4 hours, and then cooled in the furnace to release the internal residual stress and obtain the annealed bar.

[0046] Bar cutting: The annealed bar is fixed on the fixture of a diamond multi-wire cutting machine and cut with electroplated diamond steel wire with a diameter of 0.15 mm. The wire feed speed is controlled at 0.2 mm / min to obtain a super magnetostrictive bar slice with a thickness of 3.0 mm.

[0047] After ultrasonically cleaning the insulating sheet (mica sheet, 40 mm wide, 60 mm long, and 90 μm thick) with anhydrous ethanol for 10 min, it was taken out and dried at 60℃ for 30 min. Then, phenolic resin particles were sprayed onto the surface of the insulating sheet by electrostatic spraying, so that a phenolic resin particle layer was formed on the surface of the insulating sheet.

[0048] The surface of the insulating sheet is the surface opposite to the surface of the supermagnetic-strictive rod slice in the laminated supermagnetic-strictive material; the phenolic resin is 2123 phenolic resin (softening point 98-115℃, curing temperature ≥150℃). The average particle size of the phenolic resin particles is 30μm.

[0049] Electrostatic spraying was performed using an electrostatic spraying machine (Changsha Hengyi Electromechanical Equipment Co., Ltd., model: HY-801);

[0050] During electrostatic spraying, the spraying pressure is controlled at 0.1 MPa, the voltage at 60 kV, the spraying direction of the spray gun is kept perpendicular to the surface of the insulating sheet, the distance between the spray gun and the insulating sheet is 15 cm, and the moving speed of the spray gun is 10 mm / s. The spray gun is moved back and forth along the length of the insulating sheet for three rounds of spraying. Every 5 seconds of spraying, the spray gun is stopped and spraying is paused for another 5 seconds. After spraying one side, the insulating sheet is rotated so that the unsprayed side faces the spray gun. The same operation is repeated to evenly spray both sides of the insulating sheet.

[0051] S2. Alternately stack super magnetostrictive rod slices and insulating sheets with phenolic resin particle layers to obtain a prefabricated stack;

[0052] S3. After clamping and fixing the prefabricated stack 6 with a clamp, heat it at 100°C for 30 minutes, then at 130°C for 40 minutes, and then at 180°C for 60 minutes. After cooling, a layered super magnetostrictive material is obtained.

[0053] Among them, see Figure 2 and Figure 3The clamp includes a frame 1 with openings at the top and bottom. A clamping body is provided inside the frame 1. The clamping body includes a first clamping body 2 and a second clamping body 3 arranged opposite each other. The first clamping body 2 has a first recess on its side facing the second clamping body 3, and the second clamping body 3 has a second recess on its side facing the first clamping body 2. When the first clamping body 2 and the second clamping body 3 are closed, they form a clamping body (rectangular in shape), and the first and second recesses combine to form a space for clamping the prefabricated stacked body 6. The frame 1 is provided with four mutually perpendicular first bolts 4 (divided into two groups arranged opposite each other) and second bolts 2. Bolt 5 (4 in total, divided into 2 groups arranged opposite each other), the first bolt 4 and the second bolt 5 are both threaded to the frame 1 (the frame 1 is provided with threaded through holes so that the frame can be threaded to the first bolt 4 and the second bolt 5). The side of the first clamping body 2 away from the first recess and the side of the second clamping body 3 away from the second recess are both provided with blind holes 7. The blind holes 7 are provided with internal threads so as to cooperate with the first bolt to achieve threaded connection. When the prefabricated stacked body 6 is in a fixed state, the first bolt 4 passes through the frame 1 and is threaded to the clamping body through the blind hole 7, and the second bolt 5 passes through the frame 1 and abuts against the clamping body.

[0054] S4. The stacked super magnetostrictive material is precision machined using a centerless grinder to make the roughness Ra of the outer cylindrical surface (i.e., cylindrical surface) ≤0.8μm; then the end faces of both ends of the stacked super magnetostrictive material are corrected using a surface grinder, with each grinding depth ≤0.01mm, and finally ensuring that the flatness is ≤0.01mm.

[0055] See Figure 4 The structure of the layered super magnetostrictive material is regular and the gap width is uniform.

[0056] Example 2

[0057] Example 1 was repeated, except that in S1, a 40mm diameter giant magnetostrictive alloy cylindrical rod was selected, and the wire feed speed of the diamond multi-wire cutter was controlled at 0.3mm / min to obtain a 2.7mm thick giant magnetostrictive rod slice. The thickness of the insulating sheet was 85μm, and the average particle size of the phenolic resin particles was 20μm.

[0058] Comparative Example 1

[0059] Example 1 was repeated, with the only difference being that: in S1, the insulating sheet was not subjected to electrostatic spraying; in S2, epoxy resin structural adhesive (single-component epoxy resin structural adhesive, brand name TONSAN1311FS) was temporarily and uniformly applied manually to the surface of the insulating sheet (the coating thickness was controlled to be 0.1 mm), and was alternately stacked with giant magnetostrictive rod slices to obtain a pre-fabricated stack. The pre-fabricated stack was then placed in an oven and directly heated to 140°C, held at that temperature for 60 min, and cured to obtain a layered giant magnetostrictive material.

[0060] Comparative Example 2

[0061] Example 2 was repeated, except that the thickness of the insulating sheet was 90 μm. In S2, a single-component epoxy resin structural adhesive (TONSAN1311FS, coating thickness controlled at 0.1 mm) doped with microglass beads was temporarily and uniformly coated onto the surface of the insulating sheet. The average particle size of the microglass beads was 30 μm, and the addition amount was 15 wt% of the epoxy resin structural adhesive. This adhesive was then alternately stacked with giant magnetostrictive rod slices to obtain a pre-fabricated stack. The pre-fabricated stack was then placed in an oven and directly heated to 140°C, held for 60 min, and cured to obtain a layered giant magnetostrictive material.

[0062] Comparative Example 3

[0063] Repeat Example 1, except that: S3, after clamping and fixing the prefabricated stack 6 with a clamp, heat it at 150°C for 40 minutes, then heat it at 180°C for 60 minutes, and then cool it to obtain a stacked super magnetostrictive material.

[0064] Comparative Example 4

[0065] Repeat Example 1, except that in S1, the spray gun is not stopped and spraying is stopped every 5 seconds, and continuous spraying is performed.

[0066] Comparative Example 5

[0067] Repeat Example 1, except that in S1, every 5 seconds of spraying, the spray gun is controlled to stop moving and spraying is stopped for 2 seconds.

[0068] Comparative Example 6

[0069] Repeat Example 1, except that in S1, the distance between the spray gun and the insulating sheet is 8cm.

[0070] Example 3

[0071] Repeat Example 1, except that in S1, the distance between the spray gun and the insulating sheet is 10cm.

[0072] The performance test results of each embodiment and comparative example are shown in Table 1.

[0073] Table 1 Performance test results of each embodiment and comparative example

[0074]

[0075] Among them, the gap width and interlayer parallelism: the thickness of the adhesive layer (i.e. the adhesive layer between the super magnetostrictive rod slice and the insulating sheet) and the local voids were detected using a Meta-X3D inverted metallographic microscope, and the parallelism error of the upper and lower surfaces of the adhesive layer was detected.

[0076] Bond strength: Tested in accordance with the national standard GB / T 7124-2008.

[0077] Insulation resistance: Tested in accordance with the national standard GB / T 1410-2006.

[0078] Shear strength: Tested in accordance with national standard GB / T 7124-2008 "Determination of tensile shear strength of adhesives (rigid material to rigid material)".

[0079] The above embodiments should be understood as being used only to illustrate the present invention more clearly, and not to limit the scope of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope defined by the appended claims.

Claims

1. A method for producing a laminated giant magnetostrictive material comprising alternately stacked giant magnetostrictive rod pieces and insulating pieces, the adjacent giant magnetostrictive rod pieces and insulating pieces being bonded to each other by a phenol resin layer; characterized by, The preparation method comprises the following steps: ​ S1, spraying phenolic resin particles on the surface of the insulating sheet by electrostatic spraying method, so that the surface of the insulating sheet forms a phenolic resin particle layer; Wherein, the surface of the insulating sheet is the surface opposite to the super magnetostrictive rod slice in the laminated super magnetostrictive material; S2, alternately stacking the super magnetostrictive rod slice and the insulating sheet with the phenolic resin particle layer to obtain a pre-stacking body; S3, after fixing the pre-stacking body, heating at 100-115℃ for 20-40min, then heating at 120-150℃ for 20-60min, and then heating at 160-190℃ for 40-80min, and cooling to obtain a laminated super magnetostrictive material.

2. The production method according to claim 1, characterized by, The average particle size of the phenolic resin particles is 20-60μm.

3. The preparation method according to claim 1, characterized in that, The softening point of the phenolic resin is 98-115℃, and the curing temperature is ≥150℃.

4. The method of claim 1, wherein, The insulating sheet is a mica sheet.

5. The preparation method according to claim 1, characterized in that, Before S1, the insulating sheet is ultrasonically cleaned with anhydrous ethanol and then dried for standby use.

6. The method of claim 1, wherein, In S1, when electrostatic spraying is performed, the pressure of electrostatic spraying is controlled to be 0.08-0.12MPa, the spraying direction of the spray gun is kept perpendicular to the surface of the insulating sheet, the distance between the spray gun and the insulating sheet is 10-20cm, and the moving speed of the spray gun is 5-15mm / s.

7. The production method according to claim 6, wherein When electrostatic spraying is performed, the spray gun is reciprocally moved along the length direction of the insulating sheet for 2-4 rounds of spraying; wherein, every 3-6s of spraying, the spray gun is controlled to stop moving and spraying for 3-6s; after one surface of the insulating sheet is completely sprayed, the insulating sheet is rotated so that the other surface of the insulating sheet faces the spray gun, and the same operation is performed for spraying.

8. The method of any one of claims 1-6, wherein, In S3, after fixing the pre-stacking body, heating at 105-110℃ for 25-35min, then heating at 125-145℃ for 30-50min, and then heating at 165-185℃ for 50-70min.

9. The method of any one of claims 1-6, wherein, The thickness of the super magnetostrictive rod slice is 1.5-6.0mm, and the thickness of the insulating sheet is 80-100μm.

10. The method of any one of claims 1-6, wherein, In S3, the prefabricated stack is fixed with a clamp; wherein the clamp comprises an upper and lower open frame (1), the frame (1) is provided with a clamping body, the clamping body comprises a first clamping body (2) and a second clamping body (3) arranged oppositely, a first recess is formed on the side of the first clamping body (2) facing the second clamping body (3), and a second recess is formed on the side of the second clamping body (3) facing the first clamping body (2); after the first clamping body (2) and the second clamping body (3) are folded, a clamping body is formed, and the first recess and the second recess combine to form a space for clamping the prefabricated stack; the frame (1) is provided with a first bolt (4) and a second bolt (5) perpendicular to each other, the first bolt (4) and the second bolt (5) are in threaded connection with the frame (1), a blind hole (7) is formed on the side of the first clamping body (2) away from the first recess and on the side of the second clamping body (3) away from the second recess, and the blind hole (7) is provided with an internal thread; when the prefabricated stack is in a fixed state, the first bolt (4) passes through the frame (1) and is in threaded connection with the clamping body through the blind hole (7), and the second bolt (5) passes through the frame (1) and abuts against the clamping body.

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