Composite polarization device and polarization method of composite piezoelectric material

Abstract

The application relates to the field of material polarization, and relates to a composite polarization device and a polarization method of a composite piezoelectric material. The device comprises an insulating container, a negative electrode plate, a flexible insulating cover, an insulating liquid and a positive electrode needle. The flexible insulating cover is arranged on the negative electrode plate, the insulating liquid is used for filling in the insulating container, and the positive electrode needle is arranged above an open cavity of the insulating container and used for generating corona to a sample to be polarized. The device combines the advantages of two polarization methods of a direct-current oil bath polarization method and a corona polarization method. The insulating liquid is filled in the insulating container, the small gap between the insulating container and the flexible insulating cover and the complex hollow structure inside the sample to be polarized can be filled, so that the breakdown of any weak point in the polarization process can be prevented. The composite piezoelectric material is polarized by using the composite polarization device, and the polarization voltage can be improved under the condition that the corona discharge is stable and normal.

Description

Technical Field

[0001] This application relates to the field of materials polarization, and more specifically, to composite polarization devices and polarization methods for composite piezoelectric materials. Background Technology

[0002] Polarization is a forced process that excites the piezoelectric properties of a piezoelectric material by applying a strong electric field. Under the influence of the applied electric field, dipoles in a small region of the solid are reoriented from random directions to alignment according to the direction of the electric field. Common polarization methods include DC oil bath polarization and corona polarization. In oil bath polarization, a temperature-controlled oil bath is used, and the sample is placed in the oil bath while a high DC voltage is applied to the two electrodes of the sample. The electrodes cover the upper and lower surfaces of the sample. However, if the sample has a complex geometry, defects, or excessively high voltage, it can create a low-resistance conductive path or an unstable electric field between the two electrodes, resulting in violent electric sparks. This spark breakdown can directly lead to sample damage and polarization failure.

[0003] Another typical polarization method is corona polarization. It is a relatively clean, less damaging, and efficient method. A round-tipped electrode needle is placed directly above the sample, connected to the positive and negative terminals of a power supply, respectively, with the negative electrode plate below the sample. The voltage is gradually increased until a critical voltage is reached, at which point corona discharge is initiated. This method can apply a much higher voltage to the sample than oil bath polarization. Corona discharge is the process of current flowing from a charged electrode to uncharged air. This excites the air into an ionized state, making it conductive and causing charged particles to flow towards the sample surface, thus creating a high electric field across the entire sample. This method avoids contamination from the silver paste on the electrodes. However, breakdown is still unavoidable during the discharge process, and this breakdown will prevent further polarization. During corona polarization, if the sample is bulky, porous, or defective, it is easy to generate electric arcs and sparks, affecting the critical voltage and ultimately damaging the sample and disrupting the polarization.

[0004] However, for some composite piezoelectric materials, such as type 0-3 piezoelectric ceramic / resin composites, the large difference in dielectric constants between the ceramic and polymer (with ceramic particles having a much higher dielectric constant than the polymer) makes polarization of the composite material very difficult, even with a high polarization voltage. If the sample has a complex structure, the difficulty of polarization will further increase.

[0005] For this type of composite piezoelectric material, the current practice in the field is to polarize the piezoelectric composite by extending the polarization time and increasing the polarization temperature. This is because conventional methods cannot increase the voltage for polarization, as increasing the voltage in conventional methods would make the electric field unstable and cause electric sparks to break down the sample. Summary of the Invention

[0006] The purpose of this application is to provide a composite polarization device and a polarization method for composite piezoelectric materials.

[0007] In a first aspect, this application provides a composite polarization device, comprising:

[0008] An insulated container with an open mouth and a bottom wall;

[0009] Negative electrode plate; placed on the bottom wall of an insulating container; the negative electrode plate is used to place the sample to be polarized.

[0010] Flexible insulating shield; The flexible insulating shield is disposed on the negative electrode plate and is used to be positioned around the sample to be polarized.

[0011] Insulating liquid; insulating liquid used to fill insulating containers; and

[0012] The positive electrode needle is positioned above the opening of the insulating container and is used to generate a corona discharge onto the sample to be polarized.

[0013] The composite polarization device provided in this application combines the advantages of both DC oil bath polarization and corona polarization. It can be used to polarize samples with porous or irregular structures, and the sample surface no longer requires electrode coating. The insulating liquid fills the insulating container, ensuring that even the tiny gaps between the insulating container and the flexible insulating shield, as well as the complex hollow structures inside the sample to be polarized, are filled, thus preventing breakdown at any weak points during polarization. By placing the flexible insulating shield on the outside of the sample to be polarized, even if the sample has a porous structure or an irregular structure (e.g., with rough sides), it can be fixed with the flexible insulating shield, which also prevents the insulating liquid from being blown away by the continuously excited air. This allows for the polarization of samples with complex structures, uneven surfaces, or characteristic defects, and reduces the likelihood of arcing and sparking. More importantly, the insulating liquid and the flexible insulating shield increase the resistance of the sample portion in the conductive air circuit, thereby obtaining more voltage and further improving the polarization voltage and ensuring a stable corona discharge. During the polarization process, a strong corona discharge reaches the top surface of the sample, creating a stronger and more continuous electric field on both surfaces of the sample to be polarized. Using the composite polarization device of this application to polarize composite piezoelectric materials such as 0-3 type piezoelectric ceramic / resin composite materials can increase the polarization voltage while ensuring stable and normal corona discharge.

[0014] In other embodiments of this application, the height of the insulating liquid filling is at least submerged in the negative electrode plate, the bottom surface of the sample to be polarized, and part of its side surface.

[0015] In other embodiments of this application, the distance between the positive electrode needle and the oral cavity is adjustable.

[0016] In other embodiments of this application, the distance between the positive electrode needle and the oral cavity is set between 15mm and 30mm.

[0017] In other embodiments of this application, the positive electrode needle described above includes a tip and a connecting end; the tip is connected to the connecting end;

[0018] The tip is directly facing the sample to be polarized, used to generate a corona discharge to the sample; the connecting end is away from the sample to be polarized, used to connect to an external power source; an insulating protective sleeve is provided on the connecting end.

[0019] In other embodiments of this application, the aforementioned composite polarization device includes a support;

[0020] The positive electrode needle is connected to the bracket so that the positive electrode needle is fixed above the opening of the insulating container.

[0021] In other embodiments of this application, an insulating protective sleeve is provided on the aforementioned bracket.

[0022] In other embodiments of this application, the aforementioned insulating protective sleeve is made of polytetrafluoroethylene material.

[0023] Secondly, this application provides a polarization method for composite materials, wherein polarization is performed using any of the aforementioned composite polarization devices;

[0024] The method includes: placing the composite material on the negative electrode plate, setting the flexible insulating shield around the sample to be polarized; filling the insulating liquid to a height that at least submerges the bottom and sides of the sample to be polarized; controlling the distance between the positive electrode needle and the opening to be between 15mm and 30mm; connecting the negative electrode plate and the positive electrode needle to a power source for polarization.

[0025] In other embodiments of this application, the composite material described above includes a porous structure and / or an irregular structure. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A structural diagram of the composite polarization device provided for an embodiment of this application (excluding the support frame);

[0028] Figure 2 A structural diagram (including a support) of the composite polarization device provided for an embodiment of this application;

[0029] Figure 3 Polarization result diagram provided for the implementation of this application.

[0030] Icons: 10-Sample to be polarized; 20-External power supply; 30-Corona discharge; 100-Combined polarization device; 110-Insulating container; 111-Open cavity; 112-Bottom wall; 120-Negative electrode plate; 130-Flexible insulating shield; 140-Insulating liquid; 150-Positive electrode needle; 160-Support. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0032] Therefore, the following detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0033] Reference Figures 1-2 This application provides a composite polarization device 100, including: an insulating container 110, a negative electrode plate 120, a flexible insulating shield 130, an insulating liquid 140, and a positive electrode needle 150.

[0034] Furthermore, in some embodiments of this application, the insulating container 110 described above has an opening 111 and a bottom wall 112.

[0035] Furthermore, the negative electrode plate 120 is placed on the bottom wall 112 of the insulating container 110; the sample 10 to be polarized is placed on the negative electrode plate 120.

[0036] Furthermore, a flexible insulating shield 130 is disposed on the negative electrode plate 120 for placement around the sample 10 to be polarized.

[0037] Furthermore, insulating liquid 140 is filled into insulating container 110, so that negative electrode plate 120 and sample 10 to be polarized are both immersed in insulating liquid 140.

[0038] Furthermore, the positive electrode needle 150 is disposed above the opening 111 of the insulating container 110 to generate a corona discharge 30 on the sample 10 to be polarized.

[0039] When polarizing a sample using the composite polarization apparatus 100 provided in this application, a negative electrode plate 120, a flexible insulating shield 130, and a sample 10 to be polarized are placed in an insulating container 110. An insulating liquid 140 is filled in the insulating container 110, immersing the negative electrode plate 120 and the sample 10 to be polarized (the upper surface of the sample 10 is exposed to the insulating liquid 140 and under the positive electrode needle 150). The sample 10 is then placed on the negative electrode plate 120, which is connected to an external high-voltage power supply. The surface of the sample is exposed to the positive electrode needle 150, and the voltage is gradually increased to the discharge critical point, maximizing the electric field on the sample and initiating the polarization process.

[0040] The composite polarization device 100 provided in this application combines the advantages of both DC oil bath polarization and corona polarization, enabling the polarization of samples with porous or irregular structures, and eliminating the need for electrode coating on the sample surface. The insulating liquid 140 fills the insulating container 110, ensuring that the minute gaps between the insulating container 110 and the flexible insulating shield 130, as well as the complex hollow structure inside the sample 10 to be polarized, are filled, thereby preventing breakdown at any weak points during polarization. By placing the flexible insulating shield 130 on the outside of the sample 10 to be polarized, even if the sample 10 has a porous structure or an irregular structure (e.g., with rough sides), it can be fixed with the flexible insulating shield 130, while simultaneously preventing the insulating liquid 140 from being blown away by continuously excited air. This allows for the polarization of samples 10 with complex structures, uneven surfaces, or characteristic defects, and minimizes the risk of arcing and sparking. More importantly, the insulating liquid 140 and the flexible insulating shield 130 can increase the resistance of the sample portion in the conductive air circuit, thereby obtaining more voltage, and can further improve the polarization voltage and the continuous and stable corona discharge. When the polarization process is underway, a strong corona discharge reaches the top surface of the sample, forming a stronger and more continuous electric field on both surfaces of the sample 10 to be polarized.

[0041] Furthermore, in some embodiments of this application, the insulating liquid 140 described above is selected as insulating oil. Any insulating oil commonly used in the art can be selected.

[0042] Furthermore, in some embodiments of this application, the insulating liquid 140 is filled to a height that at least submerges the bottom and sides of the sample 10 to be polarized.

[0043] If the sample 10 to be polarized has a porous or irregular structure, the insulating liquid 140 will fill the connecting holes of the sample 10 to be polarized, and the flexible insulating shield 130 will tightly wrap the sample 10 to be polarized outwards.

[0044] In other words, the bottom, sides, and internal hollow structure of the sample 10 to be polarized are all immersed in the insulating liquid 140.

[0045] By immersing the bottom, sides, and internal hollow structure of the sample 10 to be polarized into the insulating liquid 140, accidental impacts from side ion air can be avoided, which would interfere with the electric field in the polarization direction.

[0046] Furthermore, in some embodiments of this application, the distance between the positive electrode needle 150 and the oral cavity 111 is adjustable.

[0047] The adjustable distance between the positive electrode needle 150 and the opening 111 means that the distance can be adjusted before polarization based on factors such as sample size. Once polarization begins, the distance between the positive electrode needle 150 and the opening 111 is kept constant during the polarization process; that is, the distance between the positive electrode needle 150 and the surface of the sample 10 to be polarized is adjusted to a fixed value. The greater the distance between the positive electrode needle 150 and the surface of the sample 10 to be polarized, the higher the excitation voltage of the critical discharge. Therefore, the appropriate height of the polarization needle can be adjusted according to the sample size so that the corona discharge can cover the sample.

[0048] Further optionally, in some embodiments of this application, the distance between the positive electrode needle 150 and the opening 111 is set between 15mm and 30mm.

[0049] Further optionally, in some embodiments of this application, the distance between the positive electrode needle 150 and the opening 111 is set between 16mm and 29mm.

[0050] For example, the distance between the positive electrode needle 150 and the opening 111 is set to 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm or 29mm.

[0051] One of the important parameters affecting the polarization area and electric field strength is the distance between the positive electrode needle 150 and the surface of the sample 10 to be polarized. The greater the distance, the higher the critical discharge excitation voltage. However, if the distance is too large or too small, the polarization effect will be poor.

[0052] Through research, the inventors discovered that when the distance between the positive electrode needle 150 and the oral cavity 111 is set between 15mm and 30mm, not only is the critical discharge excitation voltage high and stable, but the polarization effect is also good.

[0053] Furthermore, in some embodiments of this application, the positive electrode needle 150 includes a tip connection end; the tip is connected to the connection end.

[0054] Furthermore, the tip is directly facing the sample 10 to be polarized, and is used to generate a corona discharge to the sample 10; the connection end is away from the sample 10 to be polarized, and is used to connect to an external power supply 20; an insulating protective sleeve (not shown) is provided on the connection end.

[0055] In other words, apart from the positive and negative poles, all other metal components of the composite polarization device 100 of this application are shielded by an insulating protective sleeve.

[0056] By installing an insulating protective sleeve on the connection end, all metal components in the entire polarization system, except for the positive and negative poles, are shielded, thereby shielding the influence of the metal components on the electric field during polarization discharge.

[0057] Furthermore, in some embodiments of this application, the insulating protective sleeve is made of polytetrafluoroethylene material.

[0058] Insulating protective sleeves made of polytetrafluoroethylene (PTFE) not only have good shielding effect, but also have stable structure and high strength.

[0059] Furthermore, referring to Figure 2 In some embodiments of this application, the composite polarization device 100 includes a support 160.

[0060] Furthermore, the positive electrode needle 150 is connected to the bracket 160 so that the positive electrode needle 150 is fixed above the opening 111 of the insulating container 110.

[0061] The bracket facilitates the fixing of the positive electrode needle 150 above the opening 111 of the insulating container 110.

[0062] Furthermore, in some embodiments of this application, an insulating protective sleeve (not shown) is provided on the aforementioned bracket.

[0063] In other words, the entire outer surface of the aforementioned bracket 160 is wrapped with an insulating protective sleeve, so that all metal components in the entire polarization system, except for the positive and negative poles, are shielded, thereby shielding the influence of the metal components on the electric field during polarization discharge.

[0064] Furthermore, in some embodiments of this application, an insulating protective sleeve made of polytetrafluoroethylene is provided on the aforementioned bracket.

[0065] Insulating protective sleeves made of polytetrafluoroethylene (PTFE) not only provide excellent shielding but also exhibit structural stability and high strength, thus protecting the support structure while simultaneously achieving shielding. Encasing all metal components in the system, except for the positive and negative electrodes, with PTFE protective sleeves can shield the metal support structure from the influence of the electric field during corona discharge.

[0066] Furthermore, in other optional embodiments of this application, a bracket made of polytetrafluoroethylene material may also be provided.

[0067] Some embodiments of this application also provide a polarization method for composite materials, which uses the composite polarization device 100 provided in any of the foregoing embodiments for polarization.

[0068] Furthermore, in some embodiments of this application, the polarization method of such composite material includes: placing the composite material on a negative electrode plate, setting a flexible insulating shield around the sample to be polarized; filling the insulating liquid to a height that at least submerges the bottom and sides of the sample to be polarized; controlling the distance between the positive electrode needle and the opening to be between 15mm and 30mm; and connecting the negative electrode plate and the positive electrode needle to a power source for polarization.

[0069] Furthermore, in some embodiments of this application, the insulating liquid 140 fills the circumference of the flexible insulating shield 130, fills the gap between the flexible insulating shield 130 and the insulating container 110, and the porous structure of the sample 10 to be polarized.

[0070] Furthermore, in some embodiments of this application, the bottom surface, side surface, and internal hollow structure of the sample 10 to be polarized are all immersed in the insulating liquid 140.

[0071] Furthermore, in some embodiments of this application, the distance between the positive electrode needle and the oral cavity is set between 15mm and 30mm.

[0072] Further optionally, in some embodiments of this application, the distance between the positive electrode needle and the oral cavity is set between 16mm and 29mm.

[0073] For example, the distance between the positive electrode needle and the oral cavity is controlled to be 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm or 29mm.

[0074] In some embodiments of this application, the polarization voltage is controlled by an external DC power supply, and the positive electrode needle 150 and the negative electrode plate 120 in the insulating liquid 140 are respectively connected to the positive and negative terminals of the power supply.

[0075] The external power supply connected to the positive electrode needle 150 and the negative electrode plate 120 mentioned above is the same power supply.

[0076] Furthermore, the polarization temperature can be controlled, for example, by placing a heating device around the sample, controlling the temperature, and monitoring it with a thermometer.

[0077] It should be noted that any heating device conventional in this field can be used.

[0078] During polarization, the upper surface of the sample 10 to be polarized is slightly exposed to the insulating liquid 140 and placed under the positive electrode needle 150, so that the electric field obtained on the sample 10 to be polarized reaches its maximum during discharge. Finally, the voltage on the positive electrode needle 150 and the negative electrode plate 120 of the system is gradually increased to carry out the polarization process. The composite polarization device 100 of this application can meet the polarization requirements of porous, irregular and complex composite piezoelectric materials, and further improves the polarization voltage based on traditional corona polarization, making the high-voltage corona discharge process stable and long-lasting.

[0079] Furthermore, in some embodiments of this application, the composite material includes a porous structure and / or an irregular structure.

[0080] Exemplary examples, in some embodiments of this application, the composite material is a type 0-3 piezoelectric ceramic / resin composite material. Under the same conditions, the type 0-3 piezoelectric ceramic / resin composite material is polarized using the aforementioned composite polarization device 100; the type 0-3 piezoelectric ceramic / resin composite material is also polarized using a conventional corona polarization method; the polarization results are shown below. Figure 3 .

[0081] from Figure 3 It can be seen that, by using the composite polarization device 100 of this application to polarize the 0-3 type piezoelectric ceramic / resin composite material, the polarization voltage increased from 20kV to 24kV, an increase of 20%, while ensuring stable and normal corona discharge. However, the polarization voltage did not increase when using the conventional corona polarization method to polarize the 0-3 type piezoelectric ceramic / resin composite material.

[0082] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A composite polarizing device, characterized by, The composite polarization device comprises: an insulating container having an open cavity and a bottom wall; a negative electrode plate; a negative electrode plate for placing a sample to be polarized on the bottom wall of the insulating container; a flexible insulating cover for placing the sample to be polarized in a circumferential direction; an insulating liquid filled in the insulating container, and the height of the insulating liquid filled is at least submerged in the bottom surface and side surface of the sample to be polarized; and a positive electrode needle arranged above the open cavity of the insulating container for generating corona to the sample to be polarized.

2. The composite polarization device according to claim 1, wherein the distance between the positive electrode needle and the open cavity is adjustable.

3. The composite polarization device according to claim 2, wherein the distance between the positive electrode needle and the open cavity is arranged between 15 mm and 30 mm.

4. The composite polarization device according to claim 1, wherein the positive electrode needle comprises a tip portion and a connecting end; the tip portion is connected to the connecting end; the tip portion is opposite to the sample to be polarized for generating corona to the sample to be polarized; the connecting end is away from the sample to be polarized for connecting an external power supply; and an insulating protective sleeve is arranged on the connecting end.

5. The composite polarization device according to claim 1, wherein the composite polarization device comprises a support; the positive electrode needle is connected to the support so that the positive electrode needle is fixed above the open cavity of the insulating container.

6. The composite polarization device according to claim 5, wherein an insulating protective sleeve is arranged on the support.

7. The composite polarization device according to claim 4 or 6, wherein the insulating protective sleeve is made of polytetrafluoroethylene material.

8. A method of poling a composite piezoelectric material, characterized by, The composite polarization device according to any one of claims 1-7 is used for polarization; the method comprises: placing a composite piezoelectric material on the negative electrode plate, arranging a flexible insulating cover in a circumferential direction of the sample to be polarized, filling the height of the insulating liquid to at least submerge the bottom surface and side surface of the sample to be polarized, and connecting the negative electrode plate and the positive electrode needle to a power supply for polarization.

9. The polarization method of the composite piezoelectric material according to claim 8, wherein the distance between the positive electrode needle and the open cavity is arranged between 15 mm and 30 mm.

10. The polarization method of the composite piezoelectric material according to claim 8, wherein the composite piezoelectric material comprises a porous structure and / or an irregular structure.

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