A method for fabricating large-size arc-shaped type 1-3 piezoelectric composite materials

Abstract

This invention relates to a method for fabricating large-size arc-shaped type 1-3 piezoelectric composite materials. Addressing the need for large-size arc-shaped mid-to-high frequency underwater acoustic emission arrays, the method involves bonding planar piezoelectric ceramics to a flexible planar substrate, cutting, casting, re-cutting, planar splicing, bending into an arc, and casting again. This invention overcomes the limitations of traditional piezoelectric composite materials, which are constrained by processing conditions and are difficult or impossible to fabricate into large-area arc shapes. Compared to traditional mid-to-high frequency acoustic arrays assembled from multiple piezoelectric ceramic particles, this invention effectively reduces process difficulty and manufacturing costs, while improving reliability and consistency.

Description

Technical Field

[0001] This invention relates to the field of underwater acoustic engineering technology, and in particular to a method for manufacturing a large-sized arc-shaped type 1-3 piezoelectric composite material. Background Technology

[0002] In the field of underwater acoustic engineering, to improve the detection range and efficiency of active sonar equipment, the transmitting acoustic array is generally required to cover a wide beam range and radiate greater acoustic power into the water. Given a fixed operating frequency, the increase in transmitted acoustic power is limited by the cavitation threshold of the acoustic array surface; therefore, it can only be increased by increasing the effective surface area of ​​the array. Compared to linear and planar arrays, arc-shaped acoustic arrays have the characteristic that the beamwidth is related to the arc angle but independent of the arc length. This allows for an increase in the effective surface area by increasing the arc radius while maintaining a constant arc angle, thereby ensuring wide beam coverage while radiating greater acoustic power into the water and improving the detection range of the active sonar.

[0003] Given the advantages of the arc-shaped acoustic array, this type of array has been widely used in active detection sonar equipment such as multibeam bathyphones, forward-looking sonars, obstacle avoidance sonars, and anti-frogman sonars both domestically and internationally. For lower-frequency arc-shaped acoustic arrays, multiple independent watertight components are generally assembled into an arc shape. Figure 1 For mid-to-high frequency arc-shaped acoustic arrays, due to the small size and spacing of the elements, individual encapsulation is not possible. Generally, arc-shaped 1-3 or 2-2 type piezoelectric composite materials are used. Figure 2 Or an array method in which multiple piezoelectric ceramic particles are assembled and spliced ​​into an arc shape and then water-sealed as a whole. Figure 3 ).

[0004] Type 1-3 and Type 2-2 piezoelectric composite materials have advantages such as low acoustic impedance and high electromechanical conversion efficiency. Mid-to-high frequency acoustic array electrodes made from arc-shaped piezoelectric composite materials are easy to lead out, have a wide working bandwidth, and exhibit good consistency in electroacoustic performance. However, due to the size limitations of the composite materials caused by processing conditions, it is difficult or impossible to fabricate large-area arc shapes. A Type 1-3 arc-shaped or ring-shaped piezoelectric composite material and its preparation method (Huang Shifeng, Xu Dongyu, Ye Zhengmao, Sun Min, Cheng Xin, Invention Patent Application No. CN102376870, Jinan University) has developed a Type 1-3 arc-shaped or ring-shaped piezoelectric composite material. Using arc-shaped or circular piezoelectric ceramics as a framework, the composite material is prepared through cutting and casting, solving the contradiction between the large diameter of the piezoelectric ceramic ring and the limited cutting depth of the cutting machine, thus minimizing the influence of cutting instruments on the preparation process. However, this preparation method is limited by the size of the arc-shaped or circular piezoelectric ceramics themselves, making it difficult to fabricate large sizes.

[0005] A mid-to-high frequency acoustic array can be fabricated by assembling multiple piezoelectric ceramic particles into an arc shape. The arc radius and length are limited only by the arc-shaped mounting mold, allowing for large-scale fabrication. However, this method has several drawbacks: First, the large-scale arc-shaped mounting mold must simultaneously meet the requirements for both the array arc radius and the precision of the ceramic particle mounting positions, making fabrication extremely difficult and costly. Second, dozens, hundreds, or even thousands of ceramic particles are manually assembled to form the arc shape, a complex process that makes it difficult to guarantee installation accuracy and consistency. Third, the positive and negative electrodes of the arc-shaped ceramic particles are independently distributed, requiring lead wires to be welded to the positive and negative electrodes of each particle. This lead wire method is extremely difficult and unreliable. Therefore, the fabrication difficulty and cost of large-scale acoustic arrays using multiple piezoelectric ceramic particles assembled into an arc increase with size, while reliability and consistency decrease accordingly. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the problems in the prior art that the piezoelectric composite material manufacturing process is limited by the stroke of the cutting machine, making it impossible to manufacture large-size materials and that the mold splicing is difficult to meet the installation accuracy and reliable electrode lead-out, thereby providing a method for manufacturing large-size arc-shaped type 1-3 piezoelectric composite materials.

[0007] To address the aforementioned technical problems, this invention provides a method for manufacturing large-size arc-shaped type 1-3 piezoelectric composite materials. Targeting the application requirements of large-size arc-shaped mid-to-high frequency underwater acoustic emission arrays, the method involves bonding planar piezoelectric ceramics to a flexible planar substrate, followed by cutting, casting, re-cutting, planar splicing, bending into an arc, and casting. The method includes the following steps:

[0008] Step S1: The planar piezoelectric ceramic bottom surface is bonded to the first flexible base plate. The subsequent arc bending direction is the first direction I, and the direction perpendicular to the arc is the second direction II.

[0009] Step S2: Cut the planar piezoelectric ceramic along the first direction I, with the cutting depth required to penetrate the planar piezoelectric ceramic without penetrating the first layer of flexible base plate;

[0010] Step S3: Fill the first direction I cut with polymer material and allow it to cure;

[0011] Step S4: Cut the piezoelectric ceramic strip along the second direction II, with the cutting depth required to penetrate the piezoelectric ceramic strip without penetrating the first layer of flexible base plate;

[0012] Step S5: Fabricate multiple planar piezoelectric ceramic blocks, each containing a first flexible base plate, following steps S1 to S4 above;

[0013] Step S6: Using a planar upper and lower mold that matches the planar piezoelectric ceramic block, the above multiple planar piezoelectric ceramic blocks are spliced ​​together along the first direction I to form a large planar piezoelectric ceramic block, and the first layer of flexible base plate is bonded to the whole second layer of flexible base plate;

[0014] Step S7: Remove the upper and lower flat molds;

[0015] Step S8: Using an arc-shaped upper and lower mold that matches the large planar piezoelectric ceramic block, the large planar piezoelectric ceramic block that was spliced ​​together as a whole is bent and unfolded into an arc-shaped piezoelectric ceramic block along the first direction I;

[0016] Step S9: Fill the gaps between adjacent piezoelectric ceramic particles in the arc-shaped piezoelectric ceramic block with polymer material and then cure it;

[0017] Step S10: Remove the upper and lower curved molds, and remove the second and first flexible base plates;

[0018] Step S11: Grind away excess polymer material and adhesive layer protruding from the upper and lower surfaces of the piezoelectric ceramic particles;

[0019] Step S12: Prepare the upper and lower surface metal electrodes.

[0020] In one embodiment of the present invention, the length direction of the planar piezoelectric ceramic in step S1 is the first direction I.

[0021] In one embodiment of the present invention, the bottom surface of the planar piezoelectric ceramic in step S1 is uniformly either the positive electrode surface or the negative electrode surface.

[0022] In one embodiment of the present invention, the first flexible base plate and the second flexible base plate are made of rubber material or epoxy thin sheet non-metallic material.

[0023] In one embodiment of the present invention, the planar piezoelectric ceramic is bonded to the first flexible base plate, and the first flexible base plate is bonded to the second flexible base plate using an adhesive or double-sided tape that can be removed by heating or solvent soaking.

[0024] In one embodiment of the present invention, the step S6 of splicing multiple planar piezoelectric ceramic blocks into a large planar piezoelectric ceramic block can also be performed simultaneously in the second direction II.

[0025] In one embodiment of the present invention, the polymer material casting and filling in steps S3 and S9 are carried out under vacuum conditions.

[0026] In one embodiment of the present invention, the electrode preparation in step S12 can be carried out by manual or printing coating followed by curing, electroplating, vacuum coating, or magnetron sputtering.

[0027] Compared with the prior art, the above-mentioned technical solution of the present invention has the following advantages: Compared with the high-frequency acoustic array of the arc-shaped piezoelectric composite material, the present invention can overcome the limitation that the size of traditional composite materials is restricted by processing conditions and it is difficult or impossible to make them into large-area arc shapes; Compared with the traditional mid-to-high frequency acoustic array of multiple ceramic particles assembled and spliced ​​into an arc shape, the present invention can effectively reduce the process difficulty and manufacturing cost, and improve reliability and consistency. Attached Figure Description

[0028] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0029] Figure 1 A schematic diagram of a low-frequency arc-shaped acoustic array structure composed of multiple independent water-sealing elements in the prior art;

[0030] Figure 2 A schematic diagram of a high-frequency acoustic array structure in a small-sized, arc-shaped piezoelectric composite material that is integrally packaged in existing technology;

[0031] Figure 3 This is a schematic diagram of a mid-to-high frequency arc-shaped acoustic array structure composed of multiple piezoelectric ceramic particles spliced ​​together in the prior art;

[0032] Figure 4 This is a flowchart illustrating the fabrication process of the large-size arc-shaped type 1-3 piezoelectric composite material for this invention application.

[0033] Figure 5 This is a flowchart illustrating the fabrication process of the large-size arc-shaped 2-2 type piezoelectric composite material component for this invention.

[0034] like Figure 4 , Figure 5 As shown: 1. Planar piezoelectric ceramic; 2. First layer flexible base plate; 3. Piezoelectric ceramic strip; 4. Piezoelectric ceramic particles; 5. Second layer flexible base plate; 6. Surface electrode. Detailed Implementation

[0035] Example 1

[0036] like Figure 4 As shown, this embodiment provides a method for manufacturing large-size arc-shaped type 1-3 piezoelectric composite materials. Addressing the requirements for large-size arc-shaped mid-to-high frequency underwater acoustic emission arrays, the method involves bonding planar piezoelectric ceramics to a flexible planar base plate, cutting—casting—re-cutting—planar splicing—bending into an arc—casting again, and includes the following steps:

[0037] Step S1: The bottom surface of the planar piezoelectric ceramic 1 is bonded to the first flexible base plate 2 with adhesive or double-sided tape. The thickness of the planar piezoelectric ceramic 1 is determined according to the frequency of the 1-3 type composite material, and the length and width are determined according to the final large-size arc segmentation into several segments and the stroke of the cutting machine. The flexible base plate 2 can be bent into an arc shape and can be cut. The adhesive and double-sided tape can be peeled off or removed under specific temperature, solvent and other conditions.

[0038] Specifically, in the embodiment, the effective arc length can be 600mm, the height can be 80mm, the maximum cutting stroke of the cutting machine can be 100mm, the length of the planar piezoelectric ceramic 1 can be 100mm, and the width can be 80mm. The arc length direction of the acoustic array is divided into 6 segments for splicing.

[0039] Step S2: Cut the above-mentioned planar piezoelectric ceramic 1 along the first direction I to obtain several uniform and slender piezoelectric ceramic strips 3. The first direction I is recommended to be the length direction of the planar piezoelectric ceramic 1. This direction is consistent with the arc direction of the subsequent large-size arc. The cutting depth is required to cut through the planar piezoelectric ceramic 1 without cutting through the first layer of flexible base plate 2, and the cutting depth on the flexible base plate 2 should be as shallow as possible.

[0040] Step S3: Fill the gaps between the piezoelectric ceramic strips 3 with a polymer material and solidify it into a planar piezoelectric ceramic block. The polymer material can be epoxy resin. The casting and filling can be carried out under vacuum conditions with heating. After the polymer material is solidified, it should be as flush as possible with the surface of the piezoelectric ceramic strip 3.

[0041] Step S4: Cut the above-mentioned planar piezoelectric ceramic block into piezoelectric ceramic particles 4 along the second direction II. The second direction II is perpendicular to the first direction I. The cutting depth is required to cut through the piezoelectric ceramic strip 3 and the polymer material between the gaps, but not through the first layer of flexible base plate 2, and the cutting depth on the first layer of flexible base plate 2 should be as shallow as possible.

[0042] Step S5: Produce multiple planar piezoelectric ceramic blocks of the same size, each containing a flexible base plate, according to steps S1 to S4 above. The surface of the planar piezoelectric ceramic blocks should be uniformly the positive or negative electrode surface of the piezoelectric ceramic.

[0043] Step S6: Using a planar upper and lower mold that matches the planar piezoelectric ceramic block, the above-mentioned multiple planar piezoelectric ceramic blocks are spliced ​​together along the first direction I to form a large planar piezoelectric ceramic block, and the first layer flexible base plate 2 is bonded to the whole second layer flexible base plate 5 with adhesive or double-sided tape. The planar mold should ensure that the splicing size of the adjacent planar piezoelectric ceramic blocks is the same as the cutting gap size in step S4. The adhesive, double-sided tape and second layer flexible base plate 5 are the same as the requirements in step S1.

[0044] Step S7: Remove the upper and lower plane molds to obtain a large planar piezoelectric ceramic block with consistent thickness and gap size, containing the first layer and the second flexible base plate;

[0045] Step S8: Using an arc-shaped upper and lower mold that matches the large planar piezoelectric ceramic block, unfold the large planar piezoelectric ceramic block assembled into a whole along the first direction I into an arc-shaped piezoelectric ceramic block. The suitable arc-shaped upper and lower mold should be able to meet the radius size requirements of the final large-size circular arc piezoelectric composite material. The suitable arc-shaped upper and lower mold should facilitate subsequent casting and molding. The bottom surface of the arc-shaped piezoelectric ceramic block is the second layer of flexible base plate 5.

[0046] Step S9: Fill the gaps between the piezoelectric ceramic particles and the polymer material in the arc-shaped piezoelectric ceramic block with a polymer material and cure it. The polymer material can be epoxy resin. The casting and filling can be carried out under vacuum conditions with heating.

[0047] Step S10: Remove the upper and lower arc molds, remove the second flexible base plate and the first flexible base plate, grind away the excess polymer material and adhesive layer that protrude above the upper and lower surfaces of the piezoelectric ceramic particles, and obtain a large arc-shaped piezoelectric ceramic block containing piezoelectric ceramic particles 4 and polymer material filling the gaps.

[0048] Step S11: Clean the upper and lower surfaces of the large-sized arc-shaped piezoelectric ceramic block, and grind away excess polymer material and adhesive layer that protrude above the upper and lower surfaces of the piezoelectric ceramic particles;

[0049] Step S12: Prepare the upper and lower surface metal electrodes 6, that is, prepare a large-sized arc-shaped type 1-3 piezoelectric composite material sample. The upper and lower surface metal electrodes 6 can be prepared by manual or printing coating followed by curing, electroplating, vacuum coating, or magnetron sputtering. The surface metal electrodes can be prepared into different shapes according to the beam design requirements.

[0050] The large-size arc-shaped type 1-3 piezoelectric composite material prepared by the above steps includes piezoelectric ceramic particles 4 uniformly arranged along the arc direction and perpendicular to the arc direction, polymer material filling the gaps between adjacent piezoelectric ceramic particles, and metal electrodes 6 applied to the upper and lower surfaces.

[0051] Example 2

[0052] like Figure 5 As shown, this embodiment also provides a method for fabricating a large-size arc-shaped 2-2 type piezoelectric composite material, which specifically includes the following steps:

[0053] Step S1: The bottom surface of the planar piezoelectric ceramic 1 is bonded to the first flexible base plate 2 with adhesive or double-sided tape. The thickness of the planar piezoelectric ceramic 1 is determined according to the frequency of the 2-2 type composite material, and the length and width are determined according to the final large-size arc segmentation into several segments and the stroke of the cutting machine. The flexible base plate 2 can be bent into an arc shape and can be cut. The adhesive and double-sided tape can be peeled off or removed under specific temperature, solvent and other conditions.

[0054] Step S2: Cut the planar piezoelectric ceramic 1 along the second direction II to obtain a planar piezoelectric ceramic block containing several uniform and slender piezoelectric ceramic strips 3. The second direction II is recommended to be the width direction of the planar piezoelectric ceramic 1, which is perpendicular to the arc direction of the subsequent large-size arc. The cutting depth is required to cut through the planar piezoelectric ceramic 1 without cutting through the first layer of flexible base plate 2, and the cutting depth on the flexible base plate 2 should be as shallow as possible.

[0055] Step S3: Following steps S1 to S3 above, fabricate multiple planar piezoelectric ceramic blocks of the same size, each containing a flexible base plate. The surface of the planar piezoelectric ceramic blocks should be uniformly the positive or negative electrode surface of the piezoelectric ceramic.

[0056] Step S4: The following steps are performed according to steps S6 to S12 of the above-mentioned method for manufacturing large-size arc-shaped type 1-3 piezoelectric composite materials.

[0057] The large-size arc-shaped 2-2 type piezoelectric composite material prepared by the above steps includes slender piezoelectric ceramic strips 3 uniformly arranged along the arc direction, polymer material filling the gaps between adjacent ceramic strips, and metal electrodes 6 applied to the upper and lower surfaces.

[0058] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for manufacturing a large-size arc-shaped type 1-3 piezoelectric composite material, targeting the application requirements of large-size arc-shaped mid-to-high frequency underwater acoustic emission arrays, is characterized by a method of bonding planar piezoelectric ceramics to a flexible planar base plate, cutting—casting—re-cutting—planar splicing—bending into an arc—casting, and so on. Includes the following steps: Step S1: The planar piezoelectric ceramic bottom surface is bonded to the first flexible base plate. The subsequent arc bending direction is the first direction I, and the direction perpendicular to the arc is the second direction II. Step S2: Cut the planar piezoelectric ceramic along the first direction I, with the cutting depth required to penetrate the planar piezoelectric ceramic without penetrating the first layer of flexible base plate; Step S3: Fill the first direction I cut with polymer material and allow it to cure; Step S4: Cut the piezoelectric ceramic strip along the second direction II, with the cutting depth required to penetrate the piezoelectric ceramic strip without penetrating the first layer of flexible base plate; Step S5: Fabricate multiple planar piezoelectric ceramic blocks, each containing a first flexible base plate, following steps S1 to S4 above; Step S6: Using a planar upper and lower mold that matches the planar piezoelectric ceramic block, the above multiple planar piezoelectric ceramic blocks are spliced ​​together along the first direction I to form a large planar piezoelectric ceramic block, and the first layer of flexible base plate is bonded to the whole second layer of flexible base plate; Step S7: Remove the upper and lower flat molds; Step S8: Using an arc-shaped upper and lower mold that matches the large planar piezoelectric ceramic block, the large planar piezoelectric ceramic block that was spliced ​​together as a whole is bent and unfolded into an arc-shaped piezoelectric ceramic block along the first direction I; Step S9: Fill the gaps between adjacent piezoelectric ceramic particles in the arc-shaped piezoelectric ceramic block with polymer material and then cure it; Step S10: Remove the upper and lower curved molds, and remove the second and first flexible base plates; Step S11: Grind away excess polymer material and adhesive layer protruding from the upper and lower surfaces of the piezoelectric ceramic particles; Step S12: Prepare the upper and lower surface metal electrodes.

2. The method for manufacturing a large-size arc-shaped type 1-3 piezoelectric composite material according to claim 1, characterized in that: In step S1, the length direction of the planar piezoelectric ceramic is the first direction I.

3. The method for manufacturing a large-size arc-shaped type 1-3 piezoelectric composite material according to claim 1, characterized in that: In step S1, the bottom surface of the planar piezoelectric ceramic is uniformly either the positive or negative electrode surface of the piezoelectric ceramic.

4. The method for manufacturing a large-size arc-shaped type 1-3 piezoelectric composite material according to claim 1, characterized in that: The first and second flexible base plates are made of rubber or epoxy thin sheet non-metallic materials.

5. The method for manufacturing a large-size arc-shaped type 1-3 piezoelectric composite material according to claim 1, characterized in that: The planar piezoelectric ceramic is bonded to the first flexible base plate, and the first flexible base plate is bonded to the second flexible base plate using an adhesive or double-sided tape that can be removed by heating or solvent soaking.

6. The method for manufacturing a large-size arc-shaped type 1-3 piezoelectric composite material according to claim 1, characterized in that: In step S6, the assembly of multiple planar piezoelectric ceramic blocks into a large planar piezoelectric ceramic block can also be performed simultaneously in the second direction II.

7. The method for manufacturing a large-size arc-shaped type 1-3 piezoelectric composite material according to claim 1, characterized in that: In steps S3 and S9, the polymer material casting and filling are carried out under vacuum conditions.

8. The method for manufacturing a large-size arc-shaped type 1-3 piezoelectric composite material according to claim 1, characterized in that: In step S12, the electrode preparation can be carried out manually or by printing and coating followed by curing, electroplating, vacuum coating, or magnetron sputtering.

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