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

Abstract

The invention discloses a plasma-based self-assembly nonlinear conductive coating preparation system and method. The system comprises a plasma processing platform, a sample preparation platform and a curing platform, the plasma processing platform comprises a plasma discharge power supply, an oscilloscope, a gas distributor and a reaction cavity; the sample preparation platform comprises an ultrasonic stirring unit, a magnetic stirring unit and a vacuum stirring unit, the curing platform comprises a heating oven and a pouring mold arranged in the heating oven, and the pouring mold is connected with an induction electrode assembly. The plasma-based self-assembly nonlinear conductive coating preparation system not only can integrate a plasma modification technology to realize optimization of a method for preparing a coating through electric field induction, but also can consider the requirement on the bonding strength of the coating, so that the nonlinear conductive coating with excellent nonlinear conductive characteristics and good surface adhesion is prepared.

Description

Technical Field

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

[0002] Charge accumulation on the insulator surface is the main problem restricting the development of high-voltage DC gas-insulated equipment (GIS / GIL), and coating the insulator surface with a nonlinear conductive coating is a very promising charge suppression method. By doping functional fillers with nonlinear conductivity properties into the coating matrix, the charge and electric field distribution on the insulator surface can be effectively improved to increase the flashover voltage. The higher the doping concentration, the stronger the nonlinear conductivity characteristics of the coating, and the better the charge and electric field regulation effect. However, high concentrations of filler doping will reduce the mechanical strength of the coating itself and the bonding force with the insulator, which leads to poor long-term working stability of the coating prepared by the existing technology.

[0003] The use of plasma to modify the surface of materials has great application prospects. Plasma contains a large number of active particles. After reacting with the surface of insulating materials, it can open the surface chemical bonds and enhance the surface bonding between the coating and the insulating substrate. The active particles bombarding the surface of the insulating substrate can change the surface morphology and increase the surface roughness, thereby enhancing the mechanical interlocking between the coating and the insulating substrate, and jointly promoting the improvement of the bonding force. Under the action of the external electric field, the filler particles in the coating are arranged into chains along the direction of the electric field, increasing the nonlinear conductivity, improving the coating's regulation of the electric field and the suppression of the surface charge. The electric field induction enables the coating to maintain a good charge regulation effect at a lower filler concentration, which is also beneficial to the bonding between the coating and the insulating substrate. The filler particles are treated with plasma, and the filler reacts with the active particles to introduce specific functional groups to enhance the molecular polarity. Under the action of the external electric field, it is easier to form a chain-like conductive channel along the direction of the electric field than the filler that has not been treated with plasma, further enhancing the regulation of the surface charge of the nonlinear conductive coating, reducing the coating's demand for filler concentration, and is beneficial to improving 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 characteristics and good surface adhesion, which is suitable for promotion in actual engineering.

[0004] However, the preparation of such nonlinear conductive coatings requires the combination of various experimental devices such as stirring and curing, and the integration of various technical means such as plasma treatment and electric field induction. The optimal plasma treatment conditions are selected based on a large number of experiments and physical and chemical property characterization results, and electric field induction is performed during the coating curing process. This requires the design of a corresponding coating preparation system based on the above requirements. In view of this, the present invention designs 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 in view of the problems existing in the prior art.

[0006] To achieve the above object, the technical solution adopted by the present invention is: A plasma-based self-assembled nonlinear conductive coating preparation system comprises a plasma processing platform, a sample preparation platform and a curing platform; the plasma processing platform comprises 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 sample materials; 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 stock solution prepared by the sample preparation platform. The casting mold is also connected to an induction electrode assembly.

[0007] 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 conductive properties and good surface adhesion.

[0008] The plasma processing platform can perform plasma processing on sample materials through the coordinated arrangement of the reaction chamber, the plasma discharge power supply, the oscilloscope and the gas distributor. It can not only process insulating substrate materials but also nonlinear functional fillers. The structure and method are also optimized, and the processing effect is better.

[0009] The sample preparation platform prepares the plasma-treated sample material by three-stage stirring, so as to prepare a coating stock solution with nonlinear functions; the ultrasonic stirring unit utilizes the cavitation effect of ultrasonic waves and the mixing effect of the stirring rod to make the sample fully contact 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, so as to effectively remove bubbles in the coating.

[0010] The curing platform can provide a heating and electric field environment, connect 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 orderly arranged particles has better nonlinear conductivity characteristics, and can significantly improve the coating's regulation effect on the electric field and the suppression effect on surface charge.

[0011] Furthermore, the reaction chamber includes a glass base and a glass cover, the middle of the glass base is provided with a recessed area for accommodating sample materials; 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; the periphery of the glass base is also provided with air holes, the air holes are connected to the gas distributor through a conduit, and the gas distributor is connected to a gas cylinder.

[0012] Furthermore, the sample material placed in the recessed area is arranged in a stacked structure of thin layers and thick layers. If the thin layer sample material is stacked on top for plasma treatment, its thinner thickness and more uniform surface are convenient for the tester to detect, and it is easier to characterize the physical and chemical properties of the sample material surface; if the thick layer sample material is stacked on top for treatment, its larger thickness and stronger mechanical properties can meet the strength requirements of the sample material in the bonding test.

[0013] 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.

[0014] Furthermore, the ultrasonic stirring unit includes an ultrasonic oscillator, and an electric stirrer and a water bath arranged on the ultrasonic oscillator; the magnetic stirring unit includes a magnetic stirrer, and an oil bath 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.

[0015] Furthermore, the casting mold includes a mold base plate and a mold pressing plate, the mold base plate and the mold pressing plate clamp the sample material processed by the plasma processing platform and leave a casting cavity, and one side of the mold pressing plate is also provided with a casting port connected to the casting cavity.

[0016] Furthermore, the inducing 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 movement of nonlinear conductive particles in the cast nonlinear conductive coating stock solution.

[0017] A method for preparing a plasma-based self-assembled nonlinear conductive coating preparation system, the preparation method comprising 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 distributor, keeping the flow rate constant, and gradually increasing the pressure. When the air gap discharge on the surface of the insulating substrate produces a uniform and dense lavender arc, start timing. After several minutes of plasma treatment, disconnect the power supply, and place the treated insulating substrate 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, gradually pressurizing, and when the air gap discharge on the surface of the nonlinear functional filler produces uniform and dense lavender arcs, timing is started, and after the plasma treatment lasts for more than ten minutes, the power supply is disconnected, and the treated nonlinear functional filler is placed in a beaker for storage; The nonlinear conductive coating stock solution is prepared by preheating the insulating substrate and the treated nonlinear functional filler, injecting acetone into a beaker, adding a coupling agent, and oscillating the beaker by an ultrasonic vibrator to obtain an oscillation liquid; adding the preheated and dried nonlinear functional filler into the oscillation liquid, placing the beaker on the ultrasonic stirring unit for oscillation and stirring; adding the insulating substrate to the oscillation and stirring 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 is completely volatilized, and heating and stirring the solution 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 curing; after the curing is completed, taking out the casting mold from the heating oven, and after the casting mold is cooled, demolding the mold and taking out the insulator with the nonlinear conductive coating.

[0018] Furthermore, when the ultrasonic stirring unit is used for stirring, the beaker is placed in a water bath for stirring, and the stirring duration does not exceed 1 hour; when the magnetic stirring unit is used for stirring, the beaker is placed in an oil bath at a temperature below 90° C. and heated and stirred for several hours; when the vacuum stirring unit is used for stirring, the air pressure is lower than 0.01 MPa, and the stirring duration does not exceed 1 hour.

[0019] Furthermore, the heating oven is opened in advance, the casting mold is placed in the heating oven for drying and standby use, and before the processing of the vacuum stirring unit is completed, the casting mold in the heating oven is taken out, and the release agent is evenly sprayed on the surface of the casting mold, and the mold is put back into the heating oven to form a thin film on the surface of the casting mold.

[0020] Compared with the prior art, the invention has the following beneficial effects: 1. The plasma-based self-assembled nonlinear conductive coating preparation system can not only optimize the electric field induced coating preparation method by integrating plasma modification technology, but also take into account the requirements of coating bonding strength, and prepare a nonlinear conductive coating with excellent nonlinear conductivity characteristics and good surface adhesion; 2. Plasma treats the surface of the insulating substrate to enhance mechanical interlocking and surface bonding, thereby improving the bonding force between the coating and the substrate; plasma treats the nonlinear functional filler to improve the dielectric parameters and surface properties of the coating, and optimizes the electric field induced treatment process; 3. The double-layer stacked insulating substrate structure, the thin layer is used for physical and chemical performance characterization, the thick layer is used for testing the bonding force, and the analysis of the physical and chemical properties of the sample assists in the optimization of plasma reaction parameters; 4. Curing is performed using a casting mold, and the vacuum stirring unit can effectively remove bubbles in the coating, so that the coating is more evenly coated; 5. In the coating curing stage, electric field induction is used to promote the filler particles to be arranged into chains along the electric field direction to form a conductive channel. The electric field induction enables the coating to maintain a good charge regulation effect at a lower filler concentration, which is also helpful to improve the bonding strength between the coating and the insulating substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the process of the plasma-based self-assembled nonlinear conductive coating preparation system of the present invention; Figure 2 It is a schematic diagram of the structure of the plasma processing platform of the present invention; Figure 3 It is a structural schematic diagram of the sample preparation platform of the present invention; Figure 4 It is a structural schematic diagram of the curing platform of the present invention; Figure 5 It is a schematic diagram of the insulating substrate of the present invention being stacked in a reaction chamber; In the 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 grounding electrode; 10, plasma discharge power supply; 11, oscilloscope; 12, gas distributor; 13, beaker; 14, casting mold; 1401, mold bottom plate; 1402, mold pressing plate; 1403, pouring port; 15, second high-voltage electrode; 16, second grounding electrode; 17, insulating substrate; 1701, thick insulating substrate; 1702, thin insulating substrate. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "middle", "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Example 1

[0024] like Figure 1 to Figure 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, and the dielectric barrier discharge device is provided with a reaction chamber 7 for accommodating sample materials; The sample preparation platform 2 comprises 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; 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 processing platform and to cast the nonlinear conductive coating stock solution prepared by the sample preparation platform. The casting mold is also connected to an induction electrode assembly.

[0025] 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 conductive properties and good surface adhesion.

[0026] 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 distributor 12. It can not only process insulating substrate materials but also nonlinear functional fillers. Moreover, the structure and method are also optimized, and the treatment effect is better.

[0027] The sample preparation platform 2 prepares the sample material treated with plasma by three-stage stirring, so as to prepare a coating stock solution with nonlinear functions; the ultrasonic stirring unit 4 utilizes the cavitation effect of ultrasound and the mixing effect of the stirring rod to make the sample fully contact 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, so as to effectively remove bubbles in the coating.

[0028] The curing platform 3 can provide a heating and electric field environment, connect 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 orderly arranged particles has better nonlinear conductivity characteristics, which can significantly improve the coating's regulation effect on the electric field and the suppression effect on the surface charge.

[0029] 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.

[0030] The glass base 701 can be a quartz glass base, in which a cylindrical recessed area is designed to accommodate and fix the sample material. Under the control of the gas distributor 12, a gas cylinder inputs a mixed gas of a specific proportion into the reaction chamber as the background gas for the plasma reaction. Under the action of the electrode, a high-voltage electric field is applied inside the reaction chamber, and the mixed gas will be excited and discharged to generate plasma, thereby realizing plasma treatment of the sample.

[0031] 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 reserved in the center of the base for accommodating and fixing the sample.

[0032] Furthermore, the sample material placed in the recessed area 703 is arranged in a stacked structure of thin layers and thick layers. If a thin layer of sample material (such as a thin layer of insulating substrate 1702) is stacked on top for plasma treatment, its thinner thickness and more uniform surface are convenient for the tester to detect, and it is easier to characterize the physical and chemical properties of the sample material surface; if a thick layer of sample material (such as a thick layer of insulating substrate 1701) is stacked on top for treatment, its larger thickness and stronger mechanical properties can meet the strength requirements of the sample material in the bonding test. The advantages of this double-layer structure are: the thin layer is used for physical and chemical performance characterization, the thick layer is used for testing the bonding force, and the analysis of the physical and chemical properties of the sample assists in the optimization of plasma reaction parameters, thereby preparing an insulating substrate with stronger bonding force. After plasma treatment, the filler particles are more likely to form a chain-like conductive channel along the direction of the electric field, further enhancing the regulatory effect of the nonlinear conductive coating on the surface charge, reducing the coating's demand for filler concentration, and also helping to improve the bonding strength between the coating and the insulating substrate.

[0033] 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.

[0034] 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.

[0035] The formula of the insulating substrate 17 can be epoxy resin, silicone rubber, phenolic resin or polyurethane resin, etc.; the coating can be epoxy composite, polyurethane resin composite, phenolic resin composite, etc.; the nonlinear conductive filler can be silicon carbide particles, zinc oxide particles or a mixture of the two, etc. When processing SiC particles (powder), micron-sized SiC powder is placed in the cylindrical depression of the base, and the plasma ionized by the mixed gas reacts with the SiC powder and then placed in the sample preparation platform to prepare the coating.

[0036] 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, a sufficient amount of 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.

[0037] The magnetic stirring unit 5 includes a magnetic stirrer 501, and 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 at the center of the beaker 13 containing the sample to make the stirring more complete.

[0038] The vacuum stirring unit 6 includes a vacuum oven 601 and an electric stirrer disposed in the vacuum oven 601. The vacuum is drawn by an air pump 602. The electric stirrer is equipped with a ceramic stirring rod. When stirring, the stirring rod is controlled to be 1 to 2 mm away from the bottom of the beaker. The sample preparation platform 2 also includes an electronic scale for weighing the sample.

[0039] Furthermore, the casting mold 14 includes a mold base plate 1401 and a mold pressing plate 1402, the mold base plate 1401 and the mold pressing plate 1402 clamp the sample material processed by the plasma processing platform and leave a casting cavity, and one side of the mold pressing plate 1402 is also provided with a pouring port 1403 connected to the casting cavity.

[0040] Furthermore, the induced 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, and 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 stock solution.

[0041] The curing time and temperature are controlled by the heating oven 301. The casting mold 14 includes a pouring port 1403, an electrode reserved groove, and a coating groove. The coating groove is 0.1 mm thick and 20 mm wide. The size of the casting mold 14 matches the epoxy substrate after plasma treatment. The shape of the insulating substrate (epoxy substrate) can be any one of a flat sheet, a conical insulator, and a pot-type insulator. The electrode reserved groove is connected to the second high-voltage electrode, and an AC electric field is applied to the coating stock solution to induce SiC particles to form chains along the direction of the electric field. After the electric field induction is completed, the AC electric field is removed, the temperature is increased, and the composite coating is cured on the surface of the plasma-treated epoxy substrate to form a nonlinear conductive coating. Example 2

[0042] 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 comprises the following steps: 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; Step 1, treating the epoxy substrate: stacking a thick layer of epoxy substrate and a thin layer of epoxy substrate and placing them in the recessed area of ​​the reaction chamber, injecting 3% O2 ​​and 97% Ar into the reaction chamber through the gas distributor, keeping the flow rate constant, and gradually pressurizing to 12KV. When the air gap discharge between the epoxy substrate and the glass cover produces a uniform and dense lavender arc, the timing is 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.

[0043] Step 2, treating the SiC powder: putting the SiC powder into the recessed area of ​​the reaction chamber, injecting 5% O2 and 95% Ar into the reaction chamber through the gas distribution instrument, and gradually pressurizing to 15KV. When the air gap discharge between the SiC powder and the glass cover produces a uniform and dense lavender arc, the timing is 15 minutes. After 15 minutes of plasma treatment, the power is disconnected and the treated SiC powder is placed in a beaker for storage.

[0044] Step 3, prepare 10% SiC / epoxy composite coating stock solution: before preparation, take a sufficient amount of E51 epoxy substrate 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 oscillate for 15min by an ultrasonic vibrator 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 30min; add 30g of E51 epoxy resin to the oscillated and stirred solution, and oscillate the oscillation liquid for 15min. The cup was transferred to a 90°C oil bath on a magnetic stirring unit and heated and stirred for 2 hours to completely volatilize 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 volatilized, and the solution was placed in a 65°C oil bath and heated and stirred for 2 hours to fully mix the solution; the beaker was then transferred to the vacuum oven of the vacuum stirring unit, the vacuum oven temperature was controlled to 65°C, an air pump was used to evacuate air so that the air pressure in the vacuum oven was lower than 0.01MPa, the coating solution was stirred under a vacuum environment, the stirring speed was controlled to 250r / min, and the stirring was continued for 45min. After removing the bubbles in the coating solution, the SiC / epoxy composite coating stock solution was obtained.

[0045] 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 20kV, induce the SiC particles to form chains along the electric field direction, and after curing and electric field induction for 2h, turn off the AC power supply, control the heating oven temperature to 110°C, and cure for 10h. After the curing is completed, take out the casting mold from the heating oven, and take out the insulator with 10wt% SiC / epoxy composite coating after the casting mold is cooled.

[0046] 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 for standby use. 5 minutes before the end of the treatment by the vacuum stirring unit in step 3, the casting mold in the heating oven is taken out, and a layer of release agent is evenly sprayed on the surface of the casting mold, and the mold is put back into the heating oven for 2 minutes to form a thin film on the surface of the casting mold. Such a setting is very beneficial for subsequent demolding.

[0047] Although 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 the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present 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 stock solution prepared by the sample preparation platform. The casting mold is also connected to an induction electrode assembly.

2. The plasma-based self-assembled nonlinear conductive coating preparation system according to claim 1, characterized in that: The reaction chamber comprises a glass base and a glass cover, wherein 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, wherein 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, wherein 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 material placed in the recessed area is 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, and an electric stirrer and a water bath arranged on the ultrasonic oscillator; the magnetic stirring unit includes a magnetic stirrer, and an oil bath 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 plate and a mold pressing plate. The mold base plate and the mold pressing plate clamp the sample material processed by the plasma processing platform and leave a casting cavity. A casting port connected to the casting cavity is also provided on one side of the mold pressing plate.

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 stock solution.

8. A method for preparing a plasma-based self-assembled nonlinear conductive coating preparation system according to any one of claims 1 to 7, characterized in that: The preparation method 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 distributor, keeping the flow rate constant, and gradually increasing the pressure. When the air gap discharge on the surface of the insulating substrate produces a uniform and dense lavender arc, start timing. After several minutes of plasma treatment, disconnect the power supply, and place the treated insulating substrate 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, gradually pressurizing, and when the air gap discharge on the surface of the nonlinear functional filler produces uniform and dense lavender arcs, timing is started, and after the plasma treatment lasts for more than ten minutes, the power supply 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 the 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 in the magnetic stirring unit again 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 removed to take out the insulator with the nonlinear conductive coating.

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

10. The method for preparing a plasma-based self-assembled nonlinear conductive coating preparation system according to claim 8, characterized in that: The heating oven is opened in advance, and the casting mold is placed in the heating oven for drying and 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 put back into the heating oven to form a thin film on the surface of the casting mold.

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