Flexible high-entropy piezoelectric ceramic ultrasonic transducer and preparation method and application thereof

Abstract

The invention discloses a flexible high-entropy piezoelectric ceramic ultrasonic transducer and a preparation method and application thereof, and belongs to the technical field of piezoelectric composite materials and devices thereof. Metal oxide ultrathin pieces are sintered in a Joule heat heating mode to obtain high-entropy piezoelectric ceramic ultrathin pieces, the high-entropy piezoelectric ceramic ultrathin pieces and molybdenum nets are integrally formed into ultrasonic transducer units, then the ultrasonic transducer units are arranged and bonded to a flexible film in an array mode, and the flexible high-entropy piezoelectric ceramic ultrasonic transducer is manufactured. The prepared transducer has high-efficiency sound energy transmission and flexibility, is good in mechanical stress resistance, corrosion resistance and weather resistance, and can be widely applied to the fields of marine antifouling, flexible electronics, soft robots, wearable equipment and the like.

Description

Technical Field

[0001] The present invention relates to a flexible high-entropy piezoelectric ceramic ultrasonic transducer, a preparation method thereof, and an application thereof, belonging to the technical field of piezoelectric composite materials and devices. Background Art

[0002] The application of ultrasonic transducers in marine static anti-fouling has important value and significance. In the marine environment, facilities such as ship hulls, docks, and buoys are immersed in seawater for a long time and are prone to attaching marine organisms (such as algae, shellfish, and bacteria). These biological fouling not only increases the hull resistance and fuel consumption but also accelerates material corrosion, causing huge economic losses and environmental problems. Through ultrasonic vibration, the transducer generates tiny vibration waves on the surface of the ship hull or facilities, thereby interfering with and inhibiting the attachment process of organisms and achieving a lasting anti-fouling effect.

[0003] Currently, the preparation of ultrasonic transducers has attracted much attention and research. Chinese Patent CN202311259596.2 discloses an ultrasonic transducer, a preparation method thereof, and an application thereof, including the following steps: mixing piezoelectric ceramic powder in a solvent, stirring evenly to obtain a precursor slurry, filling the slurry into a template under vacuum and volatilizing the solvent to obtain a precursor array; then hot-pressing and sintering to remove the template; filling and curing with epoxy resin, grinding and thinning, sputtering an Au electrode, and polarizing to obtain a ceramic linear array with piezoelectric properties; connecting a cable to one side of the ceramic linear array and pouring a backing layer, wiring through a flexible circuit board on the other side of the ceramic linear array, then sequentially pasting a matching layer and an acoustic lens on the flexible circuit board and performing encapsulation to obtain an ultrasonic linear array transducer; Chinese Patent CN201710643625.3 discloses a piezoelectric ultrasonic transducer and a preparation method thereof. The piezoelectric ultrasonic transducer includes a diaphragm and a piezoelectric film attached to the diaphragm. A resistance structure capable of generating Joule heat to raise the local temperature of the diaphragm when energized is provided in the edge region of the diaphragm close to the substrate direction. Since the diaphragm is made of a material such as silicon dioxide whose Young's modulus decreases with the increase in temperature, heating will cause the overall elastic coefficient of the diaphragm to decrease, the electromechanical coupling coefficient of the transducer to increase, and the sound pressure output to change; on the other hand, the resonance frequency of the diaphragm during vibration decreases with the decrease in the elastic coefficient, realizing the dynamic adjustment of the ultrasonic output frequency.

[0004] However, the traditional ultrasonic transducer contains many rigid structures. Although it has high mechanical strength and stable transducer performance, it has a certain "flexibility" problem in applications with irregular surfaces such as hulls and pipelines. In addition, the core component of the piezoelectric effect in the ultrasonic transducer, the piezoelectric ceramic, is mainly based on lead zirconate titanate (PZT) ceramics, and there is no report on the use of high entropy piezoelectric ceramics. The high-temperature sintering of traditional PZT piezoelectric ceramics is usually carried out at a high temperature of 1200-1400°C. Since lead will volatilize in large quantities at this temperature, it is difficult to obtain a dense ceramic sheet with uniform composition. In addition, the high sintering temperature also causes the PZT particles to coarsen and agglomerate, reducing the microstructure and properties of the ceramic. These factors reduce the mechanical strength and service life of the existing ultrasonic transducer, limiting its use. Therefore, the prior art lacks a preparation process for an ultrasonic transducer that can simultaneously meet flexibility and good mechanical stress resistance, corrosion resistance and weather resistance. Summary of the invention

[0005] In order to solve the problems in the prior art, the present invention discloses a flexible high-entropy piezoelectric ceramic ultrasonic transducer and a preparation method and application thereof. The present invention utilizes Joule heat heating to sinter an ultra-thin sheet of metal oxide to obtain an ultra-thin sheet of high-entropy piezoelectric ceramic and shapes it into an ultrasonic transducer unit, and then arranges the ultrasonic transducer unit array and bonds it to a flexible film to obtain a flexible high-entropy piezoelectric ceramic ultrasonic transducer. The obtained transducer has both efficient sound energy transmission and flexibility, and has good resistance to mechanical stress, corrosion resistance and weather resistance, and can be widely used in marine antifouling, flexible electronics, soft robots, wearable devices and other fields.

[0006] The technical solution of the present invention is as follows:

[0007] The present invention provides a method for preparing a flexible high-entropy piezoelectric ceramic ultrasonic transducer, comprising the following steps:

[0008] S1. Fully grind and mix lead zirconate titanate and any two metal oxides corresponding to +2 or +3 valence metals to obtain a mixed metal powder; the lead zirconate titanate has 40 to 60 parts by weight and each metal oxide has 20 to 30 parts by weight; at least one of the metal oxides has a melting point lower than 1000°C;

[0009] S2, rolling and cutting the mixed metal powder into metal oxide ultra-thin sheets of not less than 2; laminating and covering the upper and lower surfaces of the metal oxide ultra-thin sheets with molybdenum mesh, wherein the molybdenum mesh located on the upper surface of the metal oxide ultra-thin sheet is used as the upper molybdenum mesh, and the molybdenum mesh located on the lower surface of the metal oxide ultra-thin sheet is used as the lower molybdenum mesh;

[0010] S3. Lead out a positive electrode wire connected to the positive pole of an external power supply on the upper molybdenum mesh, and lead out a negative electrode wire connected to the negative pole of the external power supply on the lower molybdenum mesh. Then, the metal oxide ultrathin sheet is heated to 800 °C by Joule heating under the action of current and voltage and sintered for at least 10 min, and then the current and voltage are adjusted to continue heating to 1000 °C and sintered for at least 10 min, so as to sinter and form a high-entropy piezoelectric ceramic ultrathin sheet and sinter it into one body with the upper molybdenum mesh and the lower molybdenum mesh. After cooling, an ultrasonic transducer unit is obtained;

[0011] S4. Arrange the ultrasonic transducer units in an array form and encapsulate them inside a flexible film to form an ultrasonic transducer unit array. The ultrasonic transducer units are connected in parallel to the positive and negative poles of the external power supply through the positive electrode wire and the negative electrode wire to obtain the flexible high-entropy piezoelectric ceramic ultrasonic transducer.

[0012] Further, the metal oxides corresponding to any two +2 or +3 valence metals in step S1 can be composed of any two metal oxides among vanadium pentoxide, molybdenum trioxide, and manganese dioxide with a melting point lower than 1000 °C.

[0013] Further, the metal oxides corresponding to any two +2 or +3 valence metals in step S1 can also be composed of any one of vanadium pentoxide, molybdenum trioxide, and manganese dioxide with a melting point lower than 1000 °C and any one of metal oxides such as iron(III) oxide, zinc oxide, nickel oxide, cobalt oxide, copper oxide, tungsten oxide, and titanium oxide.

[0014] Further, the mesh number of the molybdenum mesh in step S2 is 10 - 200 meshes.

[0015] Further, the length and width dimensions of the metal oxide ultrathin sheet in step S2 are 2 cm × 2 cm, and the thickness is between 50 - 300 μm; the length and width dimensions of the molybdenum mesh are 3 cm × 3 cm.

[0016] Further, the flexible film in step S4 is a polyethylene terephthalate (PET) film or a polyimide (PI) film.

[0017] Further, the bonding in step S4 is carried out through a high-strength adhesive.

[0018] The present invention also provides a flexible high-entropy piezoelectric ceramic ultrasonic transducer prepared by the above preparation method. The ultrasonic transducer includes a flexible film and ultrasonic transducer units adhesively bonded in an array on the flexible film, and the number of ultrasonic transducer units is not less than 2.

[0019] Further, the ultrasonic transducer unit is composed of a negative electrode wire, a positive electrode wire, a lower molybdenum mesh sintered into one body, a high-entropy piezoelectric ceramic ultrathin sheet, and an upper molybdenum mesh;

[0020] Among them, the upper and lower molybdenum meshes respectively cover the upper and lower surfaces of the high-entropy piezoelectric ceramic ultra-thin sheet; the positive electrode wire is led out from the upper molybdenum mesh; the negative electrode wire is led out from the lower molybdenum mesh; the upper molybdenum mesh serves as the positive electrode of the ultrasonic transducer unit and is connected to the positive electrode of the external power supply through the positive electrode wire, and the lower molybdenum mesh serves as the negative electrode of the ultrasonic transducer unit and is connected to the negative electrode of the external power supply through the negative electrode wire.

[0021] Furthermore, the ultrasonic transducer units are connected in parallel to the positive and negative electrodes of the external power supply through the positive electrode wire and the negative electrode wire.

[0022] The flexible high-entropy piezoelectric ceramic ultrasonic transducer provided by the present invention can be applied to the field of marine anti-fouling.

[0023] Different from the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention provides an innovative solution for the preparation of flexible high-performance acoustic devices. The present invention sinters metal oxide ultra-thin sheets by Joule heating to obtain high-entropy piezoelectric ceramic ultra-thin sheets and integrally forms them with molybdenum meshes into ultrasonic transducer units, and then arranges and bonds the ultrasonic transducer units in an array form on a flexible film to produce a flexible high-entropy piezoelectric ceramic ultrasonic transducer; in this process, the molybdenum mesh not only acts as a sintering electrode for sintering high-entropy piezoelectric ceramics, but also serves as a functional electrode of the ultrasonic transducer unit in the transducer; this method realizes the integral forming of the molybdenum mesh as the ultrasonic transducer electrode and the high-entropy piezoelectric ceramic as the ultrasonic transducer piezoelectric device, which not only simplifies the manufacturing process of the ultrasonic transducer, reduces the cost, but also effectively enhances the bonding between the molybdenum mesh and the high-entropy piezoelectric ceramic, can improve the mechanical strength and service life of the ultrasonic transducer, and realizes the preparation of a high-performance ultrasonic transducer with high efficiency and stability.

[0025] 2. The present invention uses lead zirconate titanate and metal oxides corresponding to any two +2 or +3 valence metals as raw materials, and heats and sinters them using Joule heat heating technology. Through high-efficiency sintering at short-time high temperatures, the preparation of high-entropy piezoelectric ceramics and their application in transducers are realized. Compared with the existing preparation process of piezoelectric ceramics for ultrasonic transducers, the Joule heat heating method takes direct current heating as the core, and simultaneously completes the high-temperature solid-state sintering and polarization of piezoelectric ceramics in the traditional preparation process. Moreover, it significantly reduces the sintering temperature and time of piezoelectric ceramics, ensures the uniformity of ceramic sintering, and solves the problems such as uneven device density and poor mechanical strength faced by traditional piezoelectric ceramics. At the same time, among the metal oxide raw materials selected for preparing piezoelectric ceramics in the present invention, the melting point of at least one metal oxide is lower than the Joule heat heating sintering temperature. On this basis, the present invention combines the high-efficiency sintering process at short-time high temperatures to ensure that at least one metal powder raw material reaches the molten state, and then coats other raw materials to form a dense multi-metal oxide structure, which makes the prepared material meet the definition of high-entropy materials and realizes the preparation of high-entropy piezoelectric ceramics. The high-entropy piezoelectric ceramics prepared by the present invention have a ceramic structure with fine grains and high density. Compared with traditional piezoelectric ceramics, high-entropy piezoelectric ceramics have excellent piezoelectric properties due to their complex chemical components and diverse lattice structures, have higher thermal stability, durability, and excellent temperature drift resistance, and can maintain stable working performance under extreme conditions.

[0026] 3. The present invention also combines the modular design of ultrasonic transducer units with flexible film encapsulation technology. The ultrasonic transducer units are distributed in an array form on the flexible film, which not only optimizes the sound field distribution and the uniformity of signal transmission, but also significantly improves the ability to fit complex surfaces. It can closely fit various irregular surfaces, such as the hull of a ship, a pipeline, or the human body, reducing sound energy loss and improving transmission efficiency. The modular design of the ultrasonic transducer units enables the transducer to dynamically adjust the frequency and power output of each unit, thereby meeting personalized needs in multiple scenarios and being widely applicable to fields such as marine antifouling, flexible electronics, soft robotics, and wearable devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the ultrasonic transducer unit.

[0028] Figure 2 It is a schematic diagram of the overall structure of the flexible piezoelectric high-entropy ceramic ultrasonic transducer.

[0029] Figure 3 It is the sound pressure value of different array sizes at different distances of the probe of the flexible piezoelectric high-entropy ceramic ultrasonic transducer from the water surface.

[0030] 1. Ultrasonic transducer unit; 2. Upper molybdenum mesh; 3. High-entropy piezoelectric ceramic; 4. Lower molybdenum mesh; 5. Positive wire; 6. Negative wire; 7. Flexible film. Detailed implementation mode

[0031] The following further describes the present invention in conjunction with the accompanying drawings and preferred embodiments. The provided embodiments are only for clarifying the present invention, rather than limiting the scope of the present invention.

[0032] Embodiment 1

[0033] This embodiment provides a preparation method for a flexible high-entropy piezoelectric ceramic ultrasonic transducer, including the following steps:

[0034] S1. By weight, 40 parts of lead zirconate titanate, 20 parts of iron(III) oxide, and 20 parts of manganese(III) oxide are fully ground and mixed to obtain mixed metal powder;

[0035] S2. The mixed metal powder is rolled and cut into at least 2 ultra-thin metal oxide sheets. The length and width dimensions of the ultra-thin metal oxide sheets are 2 cm × 2 cm, and the thickness is between 50 and 300 μm. Molybdenum meshes with a mesh number of 10 to 200 are covered on the upper and lower surfaces of the ultra-thin metal oxide sheets. Among them, the molybdenum mesh on the upper surface of the ultra-thin metal oxide sheet is used as the upper-layer molybdenum mesh, and the molybdenum mesh on the lower surface of the ultra-thin metal oxide sheet is used as the lower-layer molybdenum mesh. The length and width dimensions of the molybdenum mesh are 3 cm × 3 cm;

[0036] S3. A positive electrode wire connected to the positive pole of an external power supply is led out on the upper-layer molybdenum mesh, and a negative electrode wire connected to the negative pole of the external power supply is led out on the lower-layer molybdenum mesh. Then, the positive and negative poles of the Joule heat heating device are respectively clamped on the positive electrode wire and the negative electrode wire, and the current and voltage are adjusted to heat the ultra-thin metal oxide sheets in the upper and lower-layer molybdenum meshes to 800 °C and fired for 10 minutes, and then the current and voltage are adjusted to heat to 1000 °C and fired for 10 minutes, thereby sintering to form a high-entropy piezoelectric ceramic ultra-thin sheet. The formed high-entropy piezoelectric ceramic ultra-thin sheet is also sintered into one body with the upper-layer molybdenum mesh and the lower-layer molybdenum mesh. After cooling, an ultrasonic transducer unit is obtained;

[0037] S4. The ultrasonic transducer units are arranged in an array form and encapsulated inside a polyethylene terephthalate (PET) film to form an ultrasonic transducer unit array. The ultrasonic transducer units are connected in parallel to the positive and negative poles of the external power supply through the positive electrode wire and the negative electrode wire to obtain the flexible high-entropy piezoelectric ceramic ultrasonic transducer.

[0038] The structural schematic diagram of the ultrasonic transducer unit obtained in step S3 of this embodiment is as Figure 1As shown, the ultrasonic transducer unit 1 is composed of a negative wire 6, a positive wire 5, a lower molybdenum mesh 4 sintered into one body, a high-entropy piezoelectric ceramic ultra-thin sheet 3, and an upper molybdenum mesh 2; among them, the upper and lower molybdenum meshes respectively cover the upper and lower surfaces of the high-entropy piezoelectric ceramic ultra-thin sheet 3; the positive wire 5 is led out from the upper molybdenum mesh 2; the negative wire 6 is led out from the lower molybdenum mesh 4;

[0039] In this embodiment, the above ultrasonic transducer unit 1 is arranged and bonded in an array form on a flexible film 7 to obtain a flexible high-entropy piezoelectric ceramic ultrasonic transducer. The structural schematic diagram of the flexible high-entropy piezoelectric ceramic ultrasonic transducer is as shown in Figure 2 As shown, the number of ultrasonic transducer units 1 is not less than 2, and the ultrasonic transducer units are connected in parallel with the positive and negative poles of an external power supply through the positive wire 5 and the negative wire 6.

[0040] Embodiment 2

[0041] This embodiment provides a preparation method of a flexible high-entropy piezoelectric ceramic ultrasonic transducer, including the following steps:

[0042] S1. By weight, 60 parts of lead zirconate titanate, 30 parts of iron(III) oxide, and 30 parts of manganese(III) oxide are fully ground and mixed to obtain a mixed metal powder;

[0043] S2. The mixed metal powder is rolled and cut into metal oxide ultra-thin sheets with a number not less than 2. The length and width dimensions of the metal oxide ultra-thin sheets are 2 cm × 2 cm, and the thickness is between 50 and 300 μm; molybdenum meshes with a mesh number of 200 are covered and adhered to the upper and lower surfaces of the metal oxide ultra-thin sheets. Among them, the molybdenum mesh on the upper surface of the metal oxide ultra-thin sheet is used as the upper molybdenum mesh, and the molybdenum mesh on the lower surface of the metal oxide ultra-thin sheet is used as the lower molybdenum mesh. The length and width dimensions of the molybdenum mesh are 3 cm × 3 cm;

[0044] S3. A positive wire connected to the positive pole of an external power supply is led out on the upper molybdenum mesh, and a negative wire connected to the negative pole of an external power supply is led out on the lower molybdenum mesh. Then, the positive and negative poles of a joule heat heating device are respectively clamped on the positive wire and the negative wire, and the current and voltage are adjusted so that the metal oxide ultra-thin sheets in the upper and lower molybdenum meshes are heated to 800 °C and fired for 10 min, and then the current and voltage are adjusted to heat to 1000 °C and fired for 10 min, thereby sintering to form a high-entropy piezoelectric ceramic ultra-thin sheet. The formed high-entropy piezoelectric ceramic ultra-thin sheet is also sintered into one body with the upper molybdenum mesh and the lower molybdenum mesh. After cooling, an ultrasonic transducer unit is obtained;

[0045] S4. The ultrasonic transducer units are arranged in an array form and encapsulated inside a polyimide (PI) film to form an ultrasonic transducer unit array. The ultrasonic transducer units are connected in parallel with the positive and negative poles of an external power supply through the positive wire and the negative wire to obtain the flexible high-entropy piezoelectric ceramic ultrasonic transducer.

[0046] The ultrasonic transducer unit obtained in this embodiment has a structure similar to that of the flexible high-entropy piezoelectric ceramic ultrasonic transducer in Embodiment 1, which will not be elaborated here.

[0047] Embodiment 3

[0048] This embodiment provides a preparation method of a flexible high-entropy piezoelectric ceramic ultrasonic transducer, including the following steps:

[0049] S1. By weight, 50 parts of lead zirconate titanate, 25 parts of iron(III) oxide, and 25 parts of manganese(III) oxide are sufficiently ground and mixed to obtain mixed metal powder.

[0050] S2. The mixed metal powder is rolled and cut into at least 2 ultrathin metal oxide sheets. The length and width dimensions of the ultrathin metal oxide sheets are 2 cm × 2 cm, and the thickness is between 50 and 300 μm. Molybdenum meshes with a mesh number of 100 are attached and covered on the upper and lower surfaces of the ultrathin metal oxide sheets. Among them, the molybdenum mesh on the upper surface of the ultrathin metal oxide sheet is used as the upper-layer molybdenum mesh, and the molybdenum mesh on the lower surface of the ultrathin metal oxide sheet is used as the lower-layer molybdenum mesh. The length and width dimensions of the molybdenum meshes are 3 cm × 3 cm.

[0051] S3. A positive electrode wire connected to the positive pole of an external power supply is led out on the upper-layer molybdenum mesh, and a negative electrode wire connected to the negative pole of the external power supply is led out on the lower-layer molybdenum mesh. Then, the positive and negative poles of the Joule heat heating device are respectively clamped on the positive and negative electrode wires, and the current and voltage are adjusted to heat the ultrathin metal oxide sheets in the upper and lower-layer molybdenum meshes to 800 °C and sinter for 10 min, and then the current and voltage are adjusted to heat to 1000 °C and sinter for 10 min, so as to sinter and form a high-entropy piezoelectric ceramic ultrathin sheet. The formed high-entropy piezoelectric ceramic ultrathin sheet is also sintered into one body with the upper-layer molybdenum mesh and the lower-layer molybdenum mesh. After cooling, an ultrasonic transducer unit is obtained.

[0052] S4. The ultrasonic transducer units are arranged in an array form and encapsulated inside a polyimide (PI) film to form an ultrasonic transducer unit array. The ultrasonic transducer units are connected in parallel to the positive and negative poles of the external power supply through the positive and negative electrode wires to obtain the flexible high-entropy piezoelectric ceramic ultrasonic transducer.

[0053] The ultrasonic transducer unit obtained in this embodiment has a structure similar to that of the flexible high-entropy piezoelectric ceramic ultrasonic transducer in Embodiment 1, which will not be elaborated here.

[0054] In addition, in the preparation method of the flexible high-entropy piezoelectric ceramic ultrasonic transducer described in the above-mentioned Embodiments 1 to 3, in step S1, in addition to the iron oxide and manganese oxide listed, metal oxides corresponding to other +2 or +3 valence metals can also be selected for the preparation of the flexible high-entropy piezoelectric ceramic ultrasonic transducer, as long as at least one of the selected metal oxides has a melting point lower than 1000 °C and can form a molten state in step S3. For example, the metal oxides used can be composed of any two of vanadium pentoxide, molybdenum trioxide, and manganese oxide, all of which have melting points lower than 1000 °C, or can be composed of any one of vanadium pentoxide, molybdenum trioxide, and manganese oxide, all of which have melting points lower than 1000 °C, and any one of iron oxide, zinc oxide, nickel oxide, cobalt oxide, copper oxide, tungsten oxide, and titanium oxide.

[0055] Example 4

[0056] In this example, the flexible high-entropy piezoelectric ceramic ultrasonic transducer prepared by the preparation method of the flexible high-entropy piezoelectric ceramic ultrasonic transducer described in Example 1 was subjected to underwater sound detection, as Figure 3 shown. At a water temperature of 25 °C, the ultrasonic transducer was placed on a suspension rack and completely submerged in the water tank but not touching the bottom. A sound pressure intensity meter was used to vertically put into the water to measure the sound pressure intensity at each point in the water. The sound pressure in five distances was statistically analyzed through the sound pressure intensity meter with the positive direction of the ultrasonic transducer perpendicular to the normal direction of the surface. On the premise of not exceeding the action range of the ultrasonic transducer at each distance, 7×7 data points were divided in the plane where each distance was located for sound pressure data collection. It can be seen from the sound pressure diagram that the sound pressure intensity of the 10×10 array is smaller than that of the 20×20 array, and both show a trend of decreasing sound pressure at 200 mm and 300 mm, and the sound pressure is stable at other positions.

[0057] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A preparation method of a flexible high-entropy piezoelectric ceramic ultrasonic transducer, characterized in that, It includes the following steps: S1. Thoroughly grind and mix lead zirconate titanate with metal oxides corresponding to any two +2 or +3 valence metals to obtain a mixed metal powder; by weight, the amount of lead zirconate titanate is 40 - 60 parts, and the amount of each metal oxide is 20 - 30 parts; among the metal oxides, at least one metal oxide has a melting point below 1000 °C; S2. Roll and cut the mixed metal powder into at least two ultrathin metal oxide sheets; attach and cover molybdenum meshes on the upper and lower surfaces of the ultrathin metal oxide sheets, where the molybdenum mesh on the upper surface of the ultrathin metal oxide sheet is used as the upper-layer molybdenum mesh, and the molybdenum mesh on the lower surface of the ultrathin metal oxide sheet is used as the lower-layer molybdenum mesh; S3. Lead out a positive electrode wire connected to the positive pole of an external power supply on the upper-layer molybdenum mesh, and lead out a negative electrode wire connected to the negative pole of the external power supply on the lower-layer molybdenum mesh. The ultrathin metal oxide sheet is heated to 800 °C by Joule heating under the action of current and voltage and fired for at least 10 min, and then the current and voltage are adjusted to continue heating to 1000 °C and fired for at least 10 min, so as to sinter and form a high-entropy piezoelectric ceramic ultrathin sheet and sinter it into one body with the upper-layer molybdenum mesh and the lower-layer molybdenum mesh. After cooling, an ultrasonic transducer unit is obtained; S4. Arrange the ultrasonic transducer units in an array form and encapsulate them inside a flexible film to form an ultrasonic transducer unit array. The ultrasonic transducer units are connected in parallel to the positive and negative poles of the external power supply through the positive electrode wire and the negative electrode wire to obtain the flexible high-entropy piezoelectric ceramic ultrasonic transducer.

2. The preparation method of the flexible high-entropy piezoelectric ceramic ultrasonic transducer according to claim 1, wherein In step S1, the metal oxides corresponding to any two +2 or +3 valence metals are composed of any one of vanadium pentoxide, molybdenum trioxide, and manganese dioxide and any one of iron(III) oxide, zinc oxide, nickel oxide, cobalt oxide, copper oxide, tungsten oxide, and titanium oxide.

3. The preparation method of the flexible high-entropy piezoelectric ceramic ultrasonic transducer according to claim 1, characterized in that, In step S1, the metal oxides corresponding to any two +2 or +3 valence metals are composed of any two of vanadium pentoxide, molybdenum trioxide, and manganese dioxide.

4. The preparation method of the flexible high-entropy piezoelectric ceramic ultrasonic transducer according to claim 1, wherein, In step S2, the mesh number of the molybdenum mesh is 10 - 200 meshes.

5. The preparation method of the flexible high-entropy piezoelectric ceramic ultrasonic transducer according to claim 3, wherein, In step S2, the length and width dimensions of the ultrathin metal oxide sheet are 2 cm × 2 cm, and the thickness is between 50 - 300 μm; the length and width dimensions of the molybdenum mesh are 3 cm × 3 cm.

6. The preparation method of the flexible high-entropy piezoelectric ceramic ultrasonic transducer according to claim 1, characterized in that, In step S4, the flexible film is a polyethylene terephthalate film or a polyimide film.

7. A flexible high-entropy piezoelectric ceramic ultrasonic transducer, characterized in that, It is obtained by the preparation method of the flexible high-entropy piezoelectric ceramic ultrasonic transducer according to any one of claims 1 - 5.

8. The flexible high-entropy piezoelectric ceramic ultrasonic transducer according to claim 7, wherein The flexible high-entropy piezoelectric ceramic ultrasonic transducer includes a flexible film (7) and ultrasonic transducer units (1) encapsulated inside the flexible film in an array form, and the number of ultrasonic transducer units (1) is not less than 2.

9. The flexible high-entropy piezoelectric ceramic ultrasonic transducer according to claim 8, characterized in that, The ultrasonic transducer unit (1) is composed of a negative electrode wire (6), a positive electrode wire (5), a sintered lower molybdenum mesh (4), a high-entropy piezoelectric ceramic ultra-thin sheet (3), and an upper molybdenum mesh (2); wherein, the upper and lower molybdenum meshes respectively cover the upper and lower surfaces of the high-entropy piezoelectric ceramic ultra-thin sheet (1); the positive electrode wire (5) is led out from the upper molybdenum mesh (2); the negative electrode wire (6) is led out from the lower molybdenum mesh (4); the ultrasonic transducer units (1) are connected in parallel with the positive and negative electrodes of an external power supply through the positive electrode wire (5) and the negative electrode wire (6).

10. The flexible high-entropy piezoelectric ceramic ultrasonic transducer prepared by the preparation method of the flexible high-entropy piezoelectric ceramic ultrasonic transducer according to any one of claims 1 to 6 or the flexible high-entropy piezoelectric ceramic ultrasonic transducer according to any one of claims 7 to 9 is applied to the field of marine antifouling.

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