Plasma-based self-assembled nonlinear conductive coating preparation system and method

Abstract

The present invention discloses a plasma-based self-assembled nonlinear conductive coating preparation system and method. The system includes a plasma processing platform, a sample preparation platform, and a curing platform. The plasma processing platform includes a plasma discharge power supply, an oscilloscope, a gas distribution device, and a reaction chamber. The sample preparation platform includes an ultrasonic stirring unit, a magnetic stirring unit, and a vacuum stirring unit. The curing platform includes a heating oven and a casting mold disposed within the heating oven, the casting mold being connected to an induction electrode assembly. This plasma-based self-assembled nonlinear conductive coating preparation system not only optimizes the electric field-induced coating preparation method by integrating plasma modification technology, but also takes into account the requirements for coating bonding strength, producing a nonlinear conductive coating with excellent nonlinear conductivity properties and good surface adhesion.

Description

Technical Field

[0001] The present invention relates to the technical field of functional dielectric material preparation, and in particular to a self-assembled nonlinear conductive coating preparation system and a preparation method thereof based on plasma optimization technology. Background Art

[0002] Charge accumulation on insulator surfaces is a major issue limiting the development of high-voltage direct current gas-insulated systems (GIS / GIL). Applying nonlinear conductive coatings to insulator surfaces is a promising approach to suppressing this charge. By doping the coating matrix with functional fillers exhibiting nonlinear conductivity, the charge and electric field distribution on the insulator surface can be effectively improved, thereby increasing the flashover voltage. The higher the doping concentration, the stronger the nonlinear conductivity of the coating, and the greater the charge and electric field control effect. However, high filler concentrations reduce the mechanical strength of the coating itself and its bonding to the insulator, resulting in poor long-term stability of coatings prepared using existing technologies.

[0003] Using plasma to modify material surfaces holds great promise. Plasma contains numerous active particles that, upon interacting with the insulating material surface, can break chemical bonds and enhance the surface bonding between the coating and the insulating substrate. The bombardment of the insulating substrate surface by the active particles alters the surface morphology and increases surface roughness, thereby enhancing the mechanical interlock between the coating and the substrate, which together contribute to improved adhesion. Under the influence of an applied electric field, the filler particles in the coating align into chains along the direction of the electric field, increasing nonlinear conductivity, enhancing the coating's ability to control the electric field, and suppressing surface charge. The electric field-induced charge regulation of the coating maintains good charge regulation at low filler concentrations, which also improves the adhesion between the coating and the insulating substrate. Plasma treatment of the filler particles introduces specific functional groups that enhance molecular polarity. Under the influence of an applied electric field, the filler particles are more likely to form chain-like conductive pathways along the direction of the electric field than fillers not treated with plasma. This further enhances the surface charge regulation of the nonlinear conductive coating, reduces the required filler concentration, and improves the bonding strength between the coating and the insulating substrate. It can be seen that by using plasma technology to separately treat the insulating substrate and the filler particles in the coating, the final coating can have both excellent nonlinear conductivity properties and good surface adhesion, which is suitable for promotion in actual engineering.

[0004] However, preparing such nonlinear conductive coatings requires combining various experimental setups, such as those for stirring and curing, and integrating various technical approaches, including plasma treatment and electric field induction. Optimal plasma treatment conditions must be selected based on extensive experiments and physical and chemical property characterization results, and electric field induction must be performed during the coating curing process. This necessitates designing a corresponding coating preparation system tailored to these requirements. In light of this, the present invention has designed a self-assembled nonlinear conductive coating preparation system based on plasma optimization technology. Summary of the Invention

[0005] The purpose of the present invention is to provide a plasma-based self-assembled nonlinear conductive coating preparation system and method to address the problems existing in the prior art.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A plasma-based self-assembled nonlinear conductive coating preparation system includes a plasma processing platform, a sample preparation platform, and a curing platform; the plasma processing platform includes a dielectric barrier discharge device, and a plasma discharge power supply, an oscilloscope, and a gas distribution instrument connected to the dielectric barrier discharge device; the dielectric barrier discharge device is provided with a reaction chamber for accommodating sample materials;

[0008] The sample preparation platform comprises an ultrasonic stirring unit, a magnetic stirring unit and a vacuum stirring unit, and the ultrasonic stirring unit, the magnetic stirring unit and the vacuum stirring unit sequentially process the sample material processed by the plasma processing platform;

[0009] The curing platform includes a heating oven and a casting mold arranged in the heating oven. The casting mold is used to fix the sample material processed by the plasma processing platform and cast the nonlinear conductive coating stock solution prepared by the sample preparation platform. The casting mold is also connected to an induction electrode assembly.

[0010] This plasma-based self-assembled nonlinear conductive coating preparation system can not only integrate plasma modification technology to optimize the electric field induced coating preparation method, but also take into account the requirements of coating bonding strength to prepare nonlinear conductive coatings with excellent nonlinear conductivity properties and good surface adhesion.

[0011] The plasma processing platform can perform plasma treatment on sample materials through the coordinated arrangement of the reaction chamber, the plasma discharge power supply, the oscilloscope and the gas distribution instrument. It can not only process insulating substrate materials but also nonlinear functional fillers. Moreover, the structure and method are optimized, resulting in better treatment effects.

[0012] The sample preparation platform prepares the plasma-treated sample material through three-stage stirring to prepare a coating stock solution with nonlinear functions; the ultrasonic stirring unit uses the cavitation effect of ultrasound and the mixing effect of the stirring rod to fully contact the sample and promote the chemical reaction; the vacuum stirring unit performs a linkage process of vacuuming and stirring after the preliminary preparation of the coating stock solution is completed, which can effectively remove bubbles in the coating.

[0013] The curing platform can provide a heating and electric field environment, connect to a high-voltage power supply, and use the electric field to drive nonlinear functional filler particles to arrange into chains along the electric field direction in the insulating matrix, thereby achieving electric field induction of the coating; the coating with such orderly arranged particles has better nonlinear conductivity characteristics, which can significantly enhance the coating's regulation of the electric field and its suppression of surface charge.

[0014] Furthermore, the reaction chamber includes a glass base and a glass cover, and a recessed area for accommodating sample materials is provided in the middle of the glass base; a first grounding electrode is provided below the glass base, and a first high-voltage electrode is provided above the glass cover, the first high-voltage electrode is connected to the plasma discharge power supply, and the plasma discharge power supply is connected to the oscilloscope; a vent is also provided on the periphery of the glass base, and the vent is connected to the gas distributor through a conduit, and the gas distributor is connected to a gas cylinder.

[0015] Furthermore, the sample material placed in the recessed area is arranged in a stacked structure of thin and thick layers. If the thin layer of sample material is stacked on top for plasma treatment, its thinner thickness and more uniform surface facilitates testing by experimenters and makes it easier to characterize the physical and chemical properties of the sample material surface. If the thick layer of sample material is stacked on top for treatment, its greater thickness and stronger mechanical properties can meet the strength requirements of the sample material in the bonding test.

[0016] Furthermore, the sample material includes an insulating substrate and a nonlinear functional filler. The insulating substrate is transferred to the casting mold after being processed by the plasma processing platform. The nonlinear functional filler is processed by the plasma processing platform and then prepared by the sample preparation platform to obtain a nonlinear conductive coating stock solution.

[0017] Furthermore, the ultrasonic stirring unit includes an ultrasonic oscillator, and an electric stirrer and a water bath pot arranged on the ultrasonic oscillator; the magnetic stirring unit includes a magnetic stirrer, and an oil bath pot and a magnetic stirrer arranged on the magnetic stirrer; the vacuum stirring unit includes a vacuum oven, and an electric stirrer arranged in the vacuum oven.

[0018] Furthermore, the casting mold includes a mold base and a mold pressure plate, the mold base and the mold pressure plate clamp the sample material processed by the plasma processing platform and leave a casting cavity, and one side of the mold pressure plate is also provided with a casting port connected to the casting cavity.

[0019] Furthermore, the induction electrode assembly includes a second high-voltage electrode and a second grounding electrode connected to the casting mold and the material clamped therein, and the second high-voltage electrode and the second grounding electrode are used to induce the movement of nonlinear conductive particles in the cast nonlinear conductive coating solution.

[0020] A method for preparing a plasma-based self-assembled nonlinear conductive coating preparation system, the method comprising the following steps:

[0021] preparing sample materials, including an insulating substrate and a nonlinear functional filler, wherein the insulating substrate includes a thick-layer insulating substrate and a thin-layer insulating substrate;

[0022] Treating the insulating substrate: stacking a thick insulating substrate and a thin insulating substrate and placing them in the reaction chamber, injecting O2 and Ar into the reaction chamber through the gas distribution device, maintaining a constant flow rate, and gradually increasing the pressure. When the air gap discharge on the surface of the insulating substrate produces a uniform and dense light purple arc, the time is counted. After the plasma treatment lasts for several minutes, the power is disconnected and the treated insulating substrate is placed in a transparent plastic bag for storage.

[0023] Treating the nonlinear functional filler: placing the nonlinear functional filler in the reaction chamber, injecting O2 and Ar into the reaction chamber through the gas distribution device, and gradually increasing the pressure. When the air gap discharge on the surface of the nonlinear functional filler produces uniform and dense light purple arcs, the time is counted. After the plasma treatment lasts for more than ten minutes, the power is disconnected, and the treated nonlinear functional filler is placed in a beaker for storage.

[0024] The nonlinear conductive coating stock solution is prepared by preheating an insulating substrate and a treated nonlinear functional filler, injecting acetone into a beaker, adding a coupling agent, and vibrating the beaker with an ultrasonic vibrator to obtain an oscillation solution; adding the preheated and dried nonlinear functional filler to the oscillation solution, placing the beaker on the ultrasonic stirring unit for oscillation and stirring; adding the insulating substrate to the oscillated and stirred solution, and transferring the beaker to a magnetic stirring unit for heating and stirring to completely volatilize the acetone; adding a curing agent and an accelerator to the solution after the complete acetone volatilization, and again heating and stirring the solution in the magnetic stirring unit to fully mix the solution; then transferring the beaker to the vacuum stirring unit and stirring the solution in the beaker under a vacuum environment to obtain the nonlinear conductive coating stock solution;

[0025] Curing treatment: Assembling the insulating substrate after plasma treatment with the casting mold, pouring the nonlinear conductive coating stock solution into the casting mold, placing the casting mold in the heating oven and connecting the induction electrode assembly, setting the temperature and time of the heating oven, and performing curing; after curing is completed, removing the casting mold from the heating oven, and after the casting mold cools, removing the mold and taking out the insulator with the nonlinear conductive coating.

[0026] Furthermore, when using the ultrasonic stirring unit for stirring, the beaker is placed in a water bath for stirring, and the stirring duration does not exceed 1 hour; when using the magnetic stirring unit for stirring, the beaker is placed in an oil bath at a temperature below 90°C and heated and stirred for several hours; when using the vacuum stirring unit for stirring, the air pressure is lower than 0.01 MPa, and the stirring duration does not exceed 1 hour.

[0027] Furthermore, the heating oven is opened in advance, and the casting mold is placed in the heating oven to be dried for standby use. Before the processing of the vacuum stirring unit is completed, the casting mold in the heating oven is taken out, and a release agent is evenly sprayed on the surface of the casting mold, and the mold is placed back into the heating oven to form a thin film on the surface of the casting mold.

[0028] Compared with the prior art, the present invention has the following beneficial effects: 1. The plasma-based self-assembled nonlinear conductive coating preparation system not only optimizes the electric field-induced coating preparation method by integrating plasma modification technology, but also takes into account the requirements for coating bonding strength, thereby preparing a nonlinear conductive coating with excellent nonlinear conductivity characteristics and good surface adhesion; 2. Plasma treatment of the insulating substrate surface enhances mechanical interlocking and surface bonding, thereby improving the bonding strength between the coating and the substrate; plasma treatment of nonlinear functional fillers improves the dielectric parameters and surface properties of the coating, and optimizes the electric field-induced treatment process; 3. The double-layered insulating substrate structure uses a thin layer for physical and chemical property characterization and a thick layer for bonding testing. Analysis of the physical and chemical properties of the sample assists in optimizing the plasma reaction parameters; 4. Curing is performed using a casting mold, and a vacuum stirring unit is used to effectively remove bubbles in the coating, ensuring more uniform coating; 5. During the coating curing stage, electric field induction is used to promote the alignment of filler particles into chains along the electric field direction, forming conductive pathways. Electric field induction enables the coating to maintain good charge regulation at low filler concentrations, which also helps to improve the bonding strength between the coating and the insulating substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the process of the plasma-based self-assembled nonlinear conductive coating preparation system of the present invention;

[0030] Figure 2Schematic diagram of the structure of the plasma processing platform of the present invention;

[0031] Figure 3 Schematic diagram of the structure of the sample preparation platform of the present invention;

[0032] Figure 4 Schematic diagram of the structure of the curing platform of the present invention;

[0033] Figure 5 Schematic diagram of the insulating substrate stacked in the reaction chamber of the present invention;

[0034] Figure: 1, plasma treatment platform; 2, sample preparation platform; 3, curing platform; 301, heating oven; 4, ultrasonic stirring unit; 401, ultrasonic oscillator; 402, water bath; 403, electric stirrer; 5, magnetic stirring unit; 501, magnetic stirrer; 502, oil bath; 503, magnetic stirring bar; 6, vacuum stirring unit; 601, vacuum oven; 602, air pump; 7, reaction chamber; 701, glass base; 702, glass Cover plate; 703, recessed area; 704, vent; 8, first high-voltage electrode; 9, first ground electrode; 10, plasma discharge power supply; 11, oscilloscope; 12, gas distributor; 13, beaker; 14, casting mold; 1401, mold base plate; 1402, mold pressure plate; 1403, pouring port; 15, second high-voltage electrode; 16, second ground electrode; 17, insulating substrate; 1701, thick-layer insulating substrate; 1702, thin-layer insulating substrate. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first," "second," etc., etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Example 1

[0037] like Figures 1 to 5As shown, a plasma-based self-assembled nonlinear conductive coating preparation system includes a plasma processing platform 1, a sample preparation platform 2, and a curing platform 3; the plasma processing platform 1 includes a dielectric barrier discharge device, and a plasma discharge power supply 10, an oscilloscope 11, and a gas distribution device 12 connected to the dielectric barrier discharge device; the dielectric barrier discharge device is provided with a reaction chamber 7 for accommodating the sample material;

[0038] The sample preparation platform 2 includes an ultrasonic stirring unit 4, a magnetic stirring unit 5 and a vacuum stirring unit 6, and the ultrasonic stirring unit 4, the magnetic stirring unit 5 and the vacuum stirring unit 6 sequentially process the sample material processed by the plasma processing platform 1;

[0039] The curing platform 3 includes a heating oven 301 and a casting mold 14 arranged in the heating oven 301. The casting mold 14 is used to fix the sample material processed by the plasma treatment platform and cast the nonlinear conductive coating solution prepared by the sample preparation platform. The casting mold is also connected to an induction electrode assembly.

[0040] This plasma-based self-assembled nonlinear conductive coating preparation system can not only integrate plasma modification technology to optimize the electric field induced coating preparation method, but also take into account the requirements of coating bonding strength to prepare nonlinear conductive coatings with excellent nonlinear conductivity properties and good surface adhesion.

[0041] The plasma processing platform 1 can perform plasma treatment on sample materials through the coordinated arrangement of the reaction chamber 7, the plasma discharge power supply 10, the oscilloscope 11 and the gas distribution device 12. It can not only process insulating substrate materials but also nonlinear functional fillers. Moreover, the structure and method are also optimized, resulting in better processing effects.

[0042] The sample preparation platform 2 prepares the plasma-treated sample material through three-stage stirring to prepare a coating stock solution with nonlinear functions; the ultrasonic stirring unit 4 uses the cavitation effect of ultrasound and the mixing effect of the stirring rod to fully contact the sample and promote the chemical reaction; the vacuum stirring unit 6 performs a linkage process of vacuuming and stirring after the preliminary preparation of the coating stock solution is completed, which can effectively remove bubbles in the coating.

[0043] The curing platform 3 can provide a heating and electric field environment, connect to a high-voltage power supply, and use the electric field to drive the nonlinear functional filler particles to arrange into chains along the electric field direction in the insulating matrix, thereby achieving electric field induction of the coating; the coating with such orderly arranged particles has better nonlinear conductivity characteristics, which can significantly enhance the coating's regulation effect on the electric field and the suppression effect on surface charge.

[0044] Furthermore, the reaction chamber 7 includes a glass base 701 and a glass cover 702, and a recessed area 703 for accommodating sample materials is provided in the middle of the glass base 701; a first grounding electrode 9 is provided below the glass base 701, and a first high-voltage electrode 8 is provided above the glass cover 702, and the first high-voltage electrode 8 is connected to the plasma discharge power supply 10, and the plasma discharge power supply 10 is connected to the oscilloscope 11; a vent 704 is also provided on the periphery of the glass base 701, and the vent 704 is connected to the gas distributor 12 through a conduit, and the gas distributor 12 is connected to a gas cylinder.

[0045] The glass base 701 can be made of quartz glass, with a cylindrical recessed area designed to accommodate and secure the sample material. Under the control of the gas distributor 12, a gas cylinder delivers a specific ratio of mixed gases into the reaction chamber as the background gas for the plasma reaction. Electrodes exert a high-voltage electric field within the reaction chamber, exciting the mixed gases and causing them to discharge, generating plasma, thereby achieving plasma treatment of the sample.

[0046] Preferably, the reaction chamber 7 comprises a quartz glass cover with a thickness of 1 mm and a diameter of 90 mm and a quartz glass base with a thickness of 15 mm and a diameter of 90 mm. A cylindrical recess with a thickness of 10 mm and a diameter of 45 mm is left in the center of the base for accommodating and fixing the sample.

[0047] Furthermore, the sample material placed in the recessed area 703 is arranged in a stacked structure of thin and thick layers. If a thin layer of sample material (such as thin insulating substrate 1702) is stacked on top for plasma treatment, its thinner thickness and more uniform surface facilitate testing by experimenters and make it easier to characterize the physical and chemical properties of the sample material's surface. If a thick layer of sample material (such as thick insulating substrate 1701) is stacked on top for treatment, its greater thickness and stronger mechanical properties can meet the strength requirements of the sample material in bonding strength testing. The advantages of this two-layer structure are: the thin layer is used for physical and chemical property characterization, while the thick layer is used for bonding strength testing. Analysis of the sample's physical and chemical properties assists in optimizing plasma reaction parameters, thereby producing an insulating substrate with stronger bonding strength. After plasma treatment, the filler particles are more likely to form chain-like conductive pathways along the electric field, further enhancing the nonlinear conductive coating's ability to regulate surface charge, reducing the coating's filler concentration requirements, and also improving the bonding strength between the coating and the insulating substrate.

[0048] Preferably, both the thin layer and thick layer sample materials are cylindrical samples with a diameter of 10 mm, wherein the thickness of the thin layer is 0.5 mm and the thickness of the thick layer is 9.5 mm.

[0049] Furthermore, the sample material includes an insulating substrate 17 and a nonlinear functional filler. The insulating substrate 17 is transferred to the casting mold 14 after being processed by the plasma processing platform. The nonlinear functional filler is processed by the plasma processing platform and then prepared by the sample preparation platform to obtain a nonlinear conductive coating stock solution.

[0050] The insulating substrate 17 can be made of epoxy resin, silicone rubber, phenolic resin, or polyurethane resin; the coating can be an epoxy-based composite, a polyurethane resin composite, or a phenolic resin composite; and the nonlinear conductive filler can be silicon carbide particles, zinc oxide particles, or a mixture thereof. When processing SiC particles (powder), micron-sized SiC powder is placed in a cylindrical depression on the base. The SiC powder is reacted with plasma generated by the mixed gas, and then placed on a sample preparation platform to prepare the coating.

[0051] Furthermore, the ultrasonic stirring unit 4 includes an ultrasonic oscillator 401, and an electric stirrer 403 and a water bath 402 arranged on the ultrasonic oscillator 401. Before stirring, sufficient hot water needs to be injected into the water bath 402 so that the water level is higher than the sample liquid level in the beaker 13. The electric stirrer 403 is equipped with a ceramic stirring rod, and during stirring, the stirring rod is controlled to be 1 to 2 mm away from the bottom of the beaker containing the sample.

[0052] The magnetic stirring unit 5 includes a magnetic stirrer 501, an oil bath 502 and a magnetic stirrer 503 arranged on the magnetic stirrer 501. The high-temperature liquid oil in the oil bath 502 uses dimethyl silicone oil, and the outer surface of the magnetic stirrer 503 is made of ceramic material. When performing magnetic stirring, it is necessary to control the magnetic stirrer 503 to be located in the center of the beaker 13 containing the sample to ensure more thorough stirring.

[0053] The vacuum stirring unit 6 includes a vacuum oven 601 and an electric stirrer disposed within the vacuum oven 601. The vacuum is evacuated using an air pump 602. The electric stirrer is equipped with a ceramic stirring rod, which is kept 1-2 mm from the bottom of the beaker during stirring. The sample preparation platform 2 also includes an electronic scale for weighing the sample.

[0054] Furthermore, the casting mold 14 includes a mold base plate 1401 and a mold pressure plate 1402. The mold base plate 1401 and the mold pressure plate 1402 clamp the sample material processed by the plasma processing platform and leave a casting cavity. One side of the mold pressure plate 1402 is also provided with a pouring port 1403 connected to the casting cavity.

[0055] Furthermore, the induction electrode assembly includes a second high-voltage electrode 15 and a second grounding electrode 16 connected to the casting mold 14 and the material clamped therein. The second high-voltage electrode 15 and the second grounding electrode 16 are used to induce movement of nonlinear conductive particles in the cast nonlinear conductive coating solution.

[0056] The curing time and temperature are controlled by the heating oven 301. The casting mold 14 includes a pouring port 1403, an electrode pre-groove, and a coating groove. The coating groove is 0.1 mm thick and 20 mm wide. The dimensions of the casting mold 14 match the epoxy substrate after plasma treatment. The insulating substrate (epoxy substrate) can be in the form of a flat sheet, a tapered insulator, or a pot-shaped insulator. The electrode pre-groove is connected to a second high-voltage electrode. An AC electric field is applied to the coating solution, inducing SiC particles to form chains along the electric field. After the electric field induction is complete, the AC field is removed and the temperature is increased, allowing the composite coating to cure on the plasma-treated epoxy substrate surface, forming a nonlinear conductive coating. Example 2

[0057] Taking the preparation process of SiC / epoxy composite coating with SiC mass fraction of 10% as an example, a preparation method of a plasma-based self-assembled nonlinear conductive coating preparation system is described in detail. The preparation method includes the following steps:

[0058] Prepare sample materials, including an insulating substrate (such as an epoxy substrate) and a nonlinear functional filler (such as SiC powder), wherein the epoxy substrate includes a thick layer epoxy substrate and a thin layer epoxy substrate;

[0059] Step 1, treating the epoxy substrate: a thick layer epoxy substrate and a thin layer epoxy substrate are stacked and placed in the recessed area of ​​the reaction chamber, 3% O2 ​​and 97% Ar are injected into the reaction chamber through the gas distribution device, the flow rate is maintained constant, and the pressure is gradually increased to 12 kV. When the air gap between the epoxy substrate and the glass cover discharges to produce a uniform and dense lavender arc, the time is set for 10 minutes. After 10 minutes of plasma treatment, the power is disconnected and the treated epoxy substrate is placed in a transparent plastic bag for storage.

[0060] Step 2, treating the SiC powder: placing the SiC powder in the recessed area of ​​the reaction chamber, injecting 5% O2 and 95% Ar into the reaction chamber through the gas distribution device, and gradually increasing the pressure to 15 kV. When the air gap between the SiC powder and the glass cover discharges to produce a uniform and dense lavender arc, the time is set for 15 minutes. After 15 minutes of plasma treatment, the power is disconnected and the treated SiC powder is placed in a beaker for storage.

[0061] Step 3, prepare 10% SiC / epoxy composite coating stock solution: before preparation, take a sufficient amount of E51 epoxy base material and plasma-treated SiC powder for preheating, inject an appropriate amount of acetone (the mass is greater than the mass of epoxy resin used in the experiment) into a beaker, and use a rubber-tipped dropper to drop 0.2g of coupling agent (KH550) into the beaker, and vibrate it with an ultrasonic vibrator for 15 minutes to obtain an oscillation liquid; add 6g of preheated and dried SiC powder to the oscillation liquid, place the beaker on the ultrasonic stirring unit for oscillation and stirring, control the stirrer speed to 300r / min, and continue for 30 minutes; add 30g of E51 epoxy resin to the oscillated and stirred solution, and burn it. The cup was transferred to a 90°C oil bath on a magnetic stirring unit and heated with stirring for 2 hours to completely evaporate the acetone; 24g of a curing agent (methylhexahydrophthalic anhydride) and 0.15g of an accelerator (trimethylaminomethylphenol) were added to the solution after the acetone was completely evaporated, and the solution was placed in a 65°C oil bath and heated with stirring for 2 hours to fully mix the solution; the beaker was then transferred to a vacuum oven of the vacuum stirring unit, the vacuum oven temperature was controlled to 65°C, and the air was pumped with an air pump to make the air pressure in the vacuum oven lower than 0.01MPa. The coating solution was stirred under a vacuum environment at a stirring speed of 250r / min for 45 minutes. After removing bubbles in the coating solution, the SiC / epoxy composite coating solution was added.

[0062] Step 4, two-step curing treatment: assemble the epoxy substrate in step 1 with the casting mold, pour the SiC / epoxy composite coating stock solution into the casting mold, control the oven temperature to 90°C, turn on the AC voltage source, control the voltage amplitude to 20 kV, induce the SiC particles to form chains along the electric field direction, and after curing and electric field induction for 2 hours, turn off the AC power supply, control the heating oven temperature to 110°C, and cure for 10 hours. After curing is complete, remove the casting mold from the heating oven, and after the casting mold cools, remove the insulator with a 10 wt% SiC / epoxy composite coating.

[0063] Before curing, the heating oven is turned on in advance, and the casting mold is placed in the heating oven at 110°C for drying. 5 minutes before the end of the vacuum stirring unit treatment in step 3, the casting mold is taken out of the heating oven, and a layer of release agent is evenly sprayed on the surface of the casting mold. The mold is then placed back in the heating oven for 2 minutes to form a thin film on the surface of the casting mold. This setting is very beneficial for subsequent demolding.

[0064] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A plasma-based self-assembled nonlinear conductive coating preparation system, characterized in that: It includes a plasma processing platform, a sample preparation platform and a curing platform; the plasma processing platform includes a dielectric barrier discharge device, and a plasma discharge power supply, an oscilloscope and a gas distribution instrument connected to the dielectric barrier discharge device, and the dielectric barrier discharge device is provided with a reaction chamber for accommodating the sample material; The sample preparation platform comprises an ultrasonic stirring unit, a magnetic stirring unit and a vacuum stirring unit, and the ultrasonic stirring unit, the magnetic stirring unit and the vacuum stirring unit sequentially process the sample material processed by the plasma processing platform; The curing platform includes a heating oven and a casting mold arranged in the heating oven. The casting mold is used to fix the sample material processed by the plasma processing platform and cast the nonlinear conductive coating solution prepared by the sample preparation platform. The casting mold is also connected to an induction electrode assembly. A method for preparing a plasma-based self-assembled nonlinear conductive coating preparation system comprises the following steps: preparing sample materials, including an insulating substrate and a nonlinear functional filler, wherein the insulating substrate includes a thick-layer insulating substrate and a thin-layer insulating substrate; Treating the insulating substrate: stacking a thick insulating substrate and a thin insulating substrate and placing them in the reaction chamber, injecting O2 and Ar into the reaction chamber through the gas distribution device, maintaining a constant flow rate, and gradually increasing the pressure. When the air gap discharge on the surface of the insulating substrate produces a uniform and dense light purple arc, the time is counted. After the plasma treatment lasts for several minutes, the power is disconnected and the treated insulating substrate is placed in a transparent plastic bag for storage. Treating the nonlinear functional filler: placing the nonlinear functional filler in the reaction chamber, injecting O2 and Ar into the reaction chamber through the gas distribution device, and gradually increasing the pressure. When the air gap discharge on the surface of the nonlinear functional filler produces uniform and dense light purple arcs, the time is counted. After the plasma treatment lasts for more than ten minutes, the power is disconnected, and the treated nonlinear functional filler is placed in a beaker for storage. Preparation of nonlinear conductive coating stock solution: preheating the insulating substrate and the treated nonlinear functional filler, injecting acetone into a beaker, adding a coupling agent, and vibrating with an ultrasonic vibrator to obtain an oscillating solution; Adding the preheated and dried nonlinear functional filler to the oscillating liquid, placing the beaker on the ultrasonic stirring unit for oscillation and stirring; adding an insulating substrate to the oscillated and stirred solution, and transferring the beaker to a magnetic stirring unit for heating and stirring to completely volatilize the acetone; adding a curing agent and an accelerator to the solution after the acetone has completely volatilized, and heating and stirring again in the magnetic stirring unit to fully mix the solution; then transferring the beaker to the vacuum stirring unit and stirring the solution in the beaker under a vacuum environment to obtain the nonlinear conductive coating stock solution; Curing treatment: assembling the insulating substrate after plasma treatment with the casting mold, pouring the nonlinear conductive coating stock solution into the casting mold, placing the casting mold in the heating oven and connecting the induction electrode assembly, setting the temperature and time of the heating oven, and performing curing; After the curing is completed, the casting mold is taken out from the heating oven, and after the casting mold is cooled, the mold is demolded to take out the insulator with the nonlinear conductive coating.

2. The plasma-based self-assembled nonlinear conductive coating preparation system according to claim 1, characterized in that: The reaction chamber includes a glass base and a glass cover. A recessed area for accommodating sample materials is provided in the middle of the glass base. A first grounding electrode is provided below the glass base, and a first high-voltage electrode is provided above the glass cover. The first high-voltage electrode is connected to the plasma discharge power supply, and the plasma discharge power supply is connected to the oscilloscope. A vent is also provided on the periphery of the glass base. The vent is connected to the gas distributor via a conduit, and the gas distributor is connected to a gas cylinder.

3. The plasma-based self-assembled nonlinear conductive coating preparation system according to claim 2, characterized in that: The sample materials placed in the recessed area are arranged in a stacked structure of thin layers and thick layers.

4. The plasma-based self-assembled nonlinear conductive coating preparation system according to claim 1, characterized in that: The sample material includes an insulating substrate and a nonlinear functional filler. The insulating substrate is transferred to the casting mold after being processed by the plasma processing platform. The nonlinear functional filler is processed by the plasma processing platform and then prepared by the sample preparation platform to obtain a nonlinear conductive coating stock solution.

5. The plasma-based self-assembled nonlinear conductive coating preparation system according to claim 1, characterized in that: The ultrasonic stirring unit includes an ultrasonic oscillator, an electric stirrer and a water bath pot arranged on the ultrasonic oscillator; the magnetic stirring unit includes a magnetic stirrer, an oil bath pot and a magnetic stirrer arranged on the magnetic stirrer; the vacuum stirring unit includes a vacuum oven and an electric stirrer arranged in the vacuum oven.

6. The plasma-based self-assembled nonlinear conductive coating preparation system according to claim 1, characterized in that: The casting mold includes a mold base and a mold pressure plate. The mold base and the mold pressure plate clamp the sample material processed by the plasma processing platform and leave a casting cavity. One side of the mold pressure plate is also provided with a pouring port connected to the casting cavity.

7. The plasma-based self-assembled nonlinear conductive coating preparation system according to claim 1, characterized in that: The induction electrode assembly includes a second high-voltage electrode and a second grounding electrode connected to the casting mold and the material clamped therein. The second high-voltage electrode and the second grounding electrode are used to induce movement of nonlinear conductive particles in the cast nonlinear conductive paint solution.

8. The plasma-based self-assembled nonlinear conductive coating preparation system according to claim 1, characterized in that: When using the ultrasonic stirring unit for stirring, the beaker is placed in a water bath for stirring, and the stirring duration does not exceed 1 hour; when using the magnetic stirring unit for stirring, the beaker is placed in an oil bath at a temperature below 90°C and heated and stirred for several hours; when using the vacuum stirring unit for stirring, the air pressure is lower than 0.01 MPa, and the stirring duration does not exceed 1 hour.

9. The plasma-based self-assembled nonlinear conductive coating preparation system according to claim 1, characterized in that: The heating oven is opened in advance, and the casting mold is placed in the heating oven to dry for standby use. Before the treatment of the vacuum stirring unit is completed, the casting mold in the heating oven is taken out, and a release agent is evenly sprayed on the surface of the casting mold, and the mold is placed back into the heating oven to form a thin film on the surface of the casting mold.

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