Method for improving dispersibility of ceramic sintering powder and apparatus therefor

Abstract

The application provides a method for improving the dispersibility of ceramic sintering powder, comprising the following steps: providing a sealed vacuum box with an upper electrode, a lower electrode, an upper insulating medium plate and a lower insulating medium plate; laying ceramic sintering powder on the lower insulating medium plate; controlling the atmosphere in the sealed vacuum box; starting the alternating current power supply, and generating dielectric barrier discharge plasma between the upper insulating medium plate and the lower insulating medium plate under the action of the alternating current power supply; and treating the ceramic sintering powder with the dielectric barrier discharge plasma for a certain time. In addition, the application also provides an equipment for improving the dispersibility of ceramic sintering powder. The method and the equipment have the advantages of few steps, simple structure, high overall production efficiency and low ceramic sintering preparation cost.

Description

Technical Field

[0001] This application relates to the field of ceramic materials technology, specifically to a method and apparatus for improving the dispersibility of sintered ceramic powder. Background Technology

[0002] Ceramic materials are widely used in consumer goods, power industry, chemical industry, construction and other fields due to their excellent insulation, heat resistance, corrosion resistance and mechanical properties.

[0003] Sintering is a common method for preparing ceramics, and ceramic sintering powder is a key raw material in this process. The properties of the powder have a significant impact on subsequent sintering steps. Dispersibility is one of the key indicators for determining whether a powder is suitable for sintering. If the powder has good dispersibility, the powder particles are uniformly dispersed, allowing for lower sintering temperatures, resulting in ceramics with high density, uniform grain size distribution, and excellent electrical, mechanical, and thermal properties. Conversely, if the powder has poor dispersibility and significant particle agglomeration, it severely affects the cost and product quality of ceramics prepared by sintering.

[0004] Compared with traditional engineering ceramics, nanoceramics exhibit significantly improved strength, toughness, and ductility, and also display unique electrical, thermal, magnetic, and optical properties, demonstrating broad application potential. Nanoparticles are the basic raw material for preparing nanoceramics; however, due to their high surface activity, nanoparticles are prone to agglomeration and have poor dispersibility, which is detrimental to subsequent sintering.

[0005] Current methods for improving the dispersibility of ceramic sintered powders include passivation, additives, and solvent storage and transportation, but these methods generally suffer from problems such as high cost, low efficiency, and complex equipment. Summary of the Invention

[0006] In view of this, it is necessary to provide a method and equipment for improving the dispersibility of ceramic sintered powders in order to solve the above problems.

[0007] Some embodiments of this application provide a method for improving the dispersibility of ceramic sintered powder, the method comprising:

[0008] A sealed vacuum chamber is provided, wherein an upper electrode, a lower electrode, an upper insulating dielectric plate, and a lower insulating dielectric plate are disposed inside the sealed vacuum chamber. The upper insulating dielectric plate and the lower insulating dielectric plate are spaced apart and arranged opposite to each other. The upper electrode is connected to the upper insulating dielectric plate, and the lower electrode is connected to the lower insulating dielectric plate. The upper insulating dielectric plate and the lower insulating dielectric plate are both located between the upper electrode and the lower electrode. The upper electrode and the lower electrode are respectively connected to an AC power supply.

[0009] Ceramic sintered powder is laid on the lower insulating dielectric plate, and the ceramic sintered powder is located between the upper insulating dielectric plate and the lower insulating dielectric plate;

[0010] The atmosphere inside the sealed vacuum chamber is controlled to be an inert atmosphere;

[0011] When the AC power is turned on, the upper electrode and the lower electrode, under the action of the AC power, generate dielectric barrier discharge plasma between the upper insulating dielectric plate and the lower insulating dielectric plate; and

[0012] The ceramic sintered powder is treated with the dielectric barrier discharge plasma for a certain period of time.

[0013] In some possible implementations, in the step of laying the ceramic sintered powder on the lower insulating dielectric plate, the ceramic sintered powder is a high-purity nanoparticle with a particle size of 10 nanometers to 20 nanometers.

[0014] In some possible implementations, in the step of laying the ceramic sintered powder on the lower insulating dielectric plate, the ceramic sintered powder is evenly spread on the lower insulating dielectric plate, and the thickness of the ceramic sintered powder is 0.2 mm to 1 mm.

[0015] In some possible implementations, the dielectric barrier discharge plasma processes the ceramic sintered powder for 10 to 30 minutes.

[0016] In some possible implementations, the method further includes: adjusting the voltage frequency of the AC power supply to 8 kHz-12 kHz and the voltage amplitude to 5 kV-15 kV.

[0017] In some possible implementations, the change in Zeta potential of the ceramic sintered powder before and after dielectric barrier discharge plasma treatment is related to the voltage amplitude and treatment time as follows: Δζ = 0.01356 V 1.8107 ·T 1.0798 Wherein, Δζ is the Zeta potential difference of the ceramic sintered powder before and after treatment with the dielectric barrier discharge plasma, in millivolts; V is the voltage amplitude of the AC power supply, in kilovolts; and T is the treatment time of the ceramic sintered powder by the dielectric barrier discharge plasma, in minutes.

[0018] In some possible implementations, during the step of controlling the atmosphere inside the sealed vacuum chamber, the atmosphere of the sealed vacuum chamber is adjusted to an inert atmosphere of 0.2 atm-1 atm.

[0019] This application also provides an apparatus for improving the dispersibility of ceramic sintered powder. The apparatus includes a sealed vacuum chamber, an AC power supply, a vacuum pump, and a gas cylinder. The sealed vacuum chamber contains an upper electrode, a lower electrode, an upper insulating dielectric plate, and a lower insulating dielectric plate. The upper and lower insulating dielectric plates are spaced apart and opposite to each other. The upper electrode is connected to the upper insulating dielectric plate, and the lower electrode is connected to the lower insulating dielectric plate. The upper and lower insulating dielectric plates are located between the upper and lower electrodes. The lower insulating dielectric plate is used to lay the ceramic sintered powder. The upper and lower electrodes are respectively connected to the AC power supply. The vacuum pump is connected to the sealed vacuum chamber. The gas cylinder stores inert gas and is connected to the sealed vacuum chamber.

[0020] In some possible implementations, the AC power supply has a voltage frequency of 8 kHz to 12 kHz and a voltage amplitude of 5 kV to 15 kV.

[0021] In some possible implementations, the thickness of the upper insulating dielectric plate is 0.5 mm to 2 mm, the thickness of the lower insulating dielectric plate is 0.5 mm to 2 mm, and the air gap width between the upper insulating dielectric plate and the lower insulating dielectric plate is 2 mm to 4 mm.

[0022] Compared to existing technologies, the method and equipment described in this application involve fewer steps in obtaining highly dispersed ceramic sintered powder using dielectric barrier discharge plasma treatment. The equipment for preparing dielectric barrier discharge plasma has a simple structure, greatly improving overall production efficiency and effectively reducing the cost of ceramic sintering. Furthermore, the treated ceramic sintered powder with high dispersion can also improve the electrical, mechanical, and thermal properties of sintered ceramic products. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings in the embodiments will be briefly described 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.

[0024] Figure 1 This is a flowchart illustrating the steps of a method for improving the dispersibility of ceramic sintered powder according to some embodiments of this application.

[0025] Figure 2 This is a schematic diagram of the structure of an apparatus for improving the dispersibility of ceramic sintering powder according to some embodiments of this application.

[0026] Explanation of key component symbols:

[0027] Detailed Implementation

[0028] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0029] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. When a component is said to be "set on" another component, it can be directly set on the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] Some embodiments of this application are described in detail. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0032] See Figure 1 and Figure 2 This application provides a method for improving the dispersibility of ceramic sintered powders, the method comprising the following steps:

[0033] S1: A sealed vacuum chamber 11 is provided. Inside the sealed vacuum chamber 11, there is an upper electrode 22, a lower electrode 23, an upper insulating dielectric plate 12, and a lower insulating dielectric plate 13. The upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 are spaced apart and arranged opposite to each other. The upper electrode 22 is connected to the upper insulating dielectric plate 12, and the lower electrode 23 is connected to the lower insulating dielectric plate 13. The upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 are both located between the upper electrode 22 and the lower electrode 23. The upper electrode 22 and the lower electrode 23 are respectively connected to the AC power supply 21.

[0034] In some embodiments, the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 are aluminum oxide plates.

[0035] Of course, in other embodiments, the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 may also be other insulating dielectric materials such as glass, ceramics, and polymers, which are not limited here.

[0036] In some embodiments, the thickness of the upper insulating dielectric plate 12 is 0.5 mm to 2 mm, and the thickness of the lower insulating dielectric plate 13 is 0.5 mm to 2 mm. Controlling the thickness of the insulating dielectric plates can avoid problems such as increased thermal effects and reduced material durability caused by excessively thin dielectric plates, and can also effectively avoid a series of problems such as higher required power supply voltage and poor discharge uniformity caused by excessively thick dielectric plates.

[0037] The specific dimensions of the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 can be adapted to meet actual needs and are not limited here.

[0038] In some embodiments, the air gap width between the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 is 2 mm to 4 mm.

[0039] In some embodiments, a support member 14 is also provided inside the sealed vacuum chamber 11, and the upper electrode 22 and the lower electrode 23 are disposed inside the sealed vacuum chamber 11 by means of the support member 14. In addition, the support member 14 can also be used to adjust the relative position between the upper electrode 23 and the lower electrode 24, thereby adjusting the air gap width between the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13.

[0040] Of course, in some other embodiments, the support member 14 may be omitted.

[0041] S2: Ceramic sintered powder 40 is laid on the lower insulating medium plate 13, with the ceramic sintered powder 40 located between the upper insulating medium plate 12 and the lower insulating medium plate 13.

[0042] In some embodiments, the ceramic sintered powder 40 is evenly spread on the lower insulating medium plate 13, so that the ceramic sintered powder 40 is uniformly processed, ensuring the efficiency and quality of the processing.

[0043] In some embodiments, the thickness of the ceramic sintered powder 40 spread on the lower insulating dielectric plate 13 is 0.2 mm to 1 mm to ensure the efficiency and quality of the ceramic sintered powder 40 processing. It is understood that if the ceramic sintered powder 40 is too thin, it will result in a smaller processing volume per batch and lower processing efficiency. To maintain the efficiency of processing the same amount of ceramic sintered powder 40 with a thinner thickness, a larger powder spreading area is required, which places higher demands on the electrodes and insulating dielectric plate, and significantly increases the processing cost of the ceramic sintered powder 40. Conversely, if the ceramic sintered powder 40 is too thick, it will result in poor processing uniformity, making it impossible to obtain high-quality, well-dispersed ceramic sintered powder 40.

[0044] In some embodiments, the ceramic sintered powder 40 is a high-purity nanoparticle with a particle size of 10-20 nanometers.

[0045] Among them, the ceramic sintered powder 40 is not limited to high-purity zinc oxide nanoparticles, but can also be other high-purity nanoparticles such as silicon carbide and zirconium oxide, which are not limited here.

[0046] S3: Control the atmosphere inside the sealed vacuum chamber 11, wherein the atmosphere is an inert atmosphere.

[0047] Furthermore, the atmosphere of the sealed vacuum chamber is adjusted to an inert atmosphere of 0.2 atm-1 atm to ensure discharge uniformity. It is understood that an appropriately low gas pressure is beneficial for reducing the required power supply voltage and improving discharge uniformity; however, too low a gas pressure will lead to insufficient discharge power, while too high a pressure will lead to concentrated and unstable discharge, affecting processing efficiency and quality.

[0048] The inert atmosphere is not limited to argon, but can also be other inert gases such as helium, which is not limited here.

[0049] In some embodiments, the sealed vacuum chamber 11 is also connected to a vacuum pump 31 and a gas cylinder 32, respectively, so as to control the atmosphere and pressure inside the sealed vacuum chamber 11 by means of the vacuum pump 31 and the gas cylinder 32. The gas cylinder 32 stores inert gas.

[0050] Furthermore, gas valves 33 are respectively installed on the pipes connecting the sealed vacuum chamber 11 to the vacuum pump 31, and on the pipes connecting the sealed vacuum chamber 11 to the gas cylinder 32. The gas valves 33 are used to control the opening and closing of the connected pipes to regulate the gas pressure inside the sealed vacuum chamber 11 and the amount of inert gas injected. The sealed vacuum chamber 11 is also connected to a pressure gauge 34. The pressure gauge 34 is used to display the gas pressure inside the sealed vacuum chamber 11, facilitating the control of the atmosphere inside the sealed vacuum chamber 11.

[0051] S4: Turn on the AC power supply 21. Under the action of the AC power supply 21, the upper electrode 22 and the lower electrode 23 generate dielectric barrier discharge plasma between the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13.

[0052] In some embodiments, the AC power supply 21 has a voltage frequency of 8-12 kHz and a voltage amplitude of 5 kV-15 kV to avoid the high risk of breakdown caused by using excessively high voltage, as well as the increased processing and safety costs due to higher requirements for power supply and heat dissipation.

[0053] S5: The ceramic sintered powder 40 is treated for a certain period of time using dielectric barrier discharge plasma.

[0054] In some embodiments, the dielectric barrier discharge plasma treats the ceramic sintered powder 40 for 10 to 30 minutes.

[0055] It is understood that the method for improving the dispersibility of ceramic sintered powder in some embodiments of this application utilizes a dielectric barrier discharge device composed of various structures in a sealed vacuum chamber 11. Under AC power conditions, dielectric barrier discharge plasma is generated between the upper insulating medium 12 and the lower insulating medium plate 13. The steps of treating the ceramic sintered powder with this dielectric barrier discharge plasma to obtain highly dispersed ceramic sintered powder are few, the equipment for preparing the dielectric barrier discharge plasma has a simple structure, greatly improving overall production efficiency and effectively reducing the cost of ceramic sintering. Furthermore, sintered ceramic products using the treated highly dispersed ceramic sintered powder exhibit significantly improved electrical, mechanical, and thermal properties.

[0056] In some embodiments, the change in Zeta potential of the ceramic sintered powder 40 before and after dielectric barrier discharge plasma treatment is related to the voltage amplitude and treatment time as follows:

[0057] Δζ=0.01356·V 1.8107 ·T 1.0798

[0058] Wherein, Δζ is the Zeta potential difference of the ceramic sintered powder 40 before and after dielectric barrier discharge plasma treatment, in millivolts; V is the voltage amplitude of the AC power supply, in kilovolts; and T is the treatment time of the ceramic sintered powder 40 by the dielectric barrier discharge plasma, in minutes.

[0059] It is understandable that a higher Zeta potential value reflects better powder dispersibility. Δζ increases with increasing V and T, meaning that the effect of dielectric barrier discharge plasma treatment on improving the dispersibility of ceramic sintered powder 40 increases with increasing voltage amplitude and treatment time.

[0060] In some embodiments, the method for improving the dispersibility of ceramic sintered powder further includes, before step S2: drying the ceramic sintered powder by baking or other methods, which can effectively improve the utilization efficiency of the ceramic sintered powder.

[0061] It is understood that the method for improving the dispersibility of ceramic sintered powder in this application is not limited by the order of the steps described above, as long as the treatment of ceramic sintered powder 40 by dielectric barrier discharge plasma can be completed, there is no restriction on the order of steps here.

[0062] The present application's solution will be explained below with reference to embodiments. Those skilled in the art will understand that the following examples are for illustrative purposes only and should not be construed as limiting the present application. Unless otherwise specified, reagents, software, and instruments involved in the following embodiments are all conventional commercially available products or open-source materials.

[0063] Example 1

[0064] (1) A sealed vacuum chamber 11 is provided. The sealed vacuum chamber 11 contains an upper electrode 22, a lower electrode 23, an upper insulating dielectric plate 12, a lower insulating dielectric plate 13, and a support member 14. The upper electrode 22 and the lower electrode 23 are both mounted on the support member 14 and connected to an AC power supply 21. The upper insulating dielectric plate 12 is connected to the upper electrode 22, and the lower insulating dielectric plate 13 is connected to the lower electrode 23. The upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 are spaced apart and opposite to each other, and are located between the upper electrode 22 and the lower electrode 23. The air gap width between the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 is 3 mm. Both the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 are alumina plates.

[0065] (2) Select ceramic sintered powder with a particle size of 10-20 nanometers and dry it. Among them, the ceramic sintered powder in Example 1 is high-purity zinc oxide nanoparticles.

[0066] (3) The dried high-purity zinc oxide nanopowder is evenly spread on a 50 mm × 50 mm × 1 mm lower insulating dielectric plate 13. The thickness of the high-purity zinc oxide nanopowder spread on the lower insulating dielectric plate 13 is 0.5 mm.

[0067] (4) Adjust the atmosphere inside the sealed vacuum chamber 11 to an argon atmosphere of 0.5 atm.

[0068] (5) When the AC power supply 21 is turned on, the upper electrode 22 and the lower electrode 23 generate dielectric barrier discharge plasma between the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 under the action of the AC power supply 21. The voltage frequency of the AC power supply is 10 kHz and the voltage amplitude is 5 kV.

[0069] (6) High-purity zinc oxide nanoparticles were treated with dielectric barrier discharge plasma for 10 minutes.

[0070] (7) Turn off the power and collect the processed powder.

[0071] (8) Test the processed powder.

[0072] The specific surface area of ​​the ceramic sintered powder before and after treatment was tested using a BET specific surface area analyzer. The test results showed that the specific surface area of ​​the ceramic sintered powder before treatment was 23.377 m². 2 g -1 The specific surface area of ​​the ceramic sintered powder treated with dielectric barrier discharge plasma is 26.712 m². 2 g -1 Therefore, it can be seen that the specific surface area of ​​the ceramic sintered powder treated with dielectric barrier discharge plasma increased by 14.27% compared with the untreated ceramic sintered powder.

[0073] The dispersibility of ceramic sintered powder before and after treatment was characterized by measuring the Zeta potential. Specifically, the ceramic sintered powder was dispersed in anhydrous ethanol, the pH was adjusted with sodium hydroxide, and after magnetic stirring and ultrasonic dispersion at room temperature, the Zeta potential values ​​of the powder before and after dielectric barrier discharge plasma treatment were measured using a NanoZS Zeta potential meter. The Zeta potential value of the powder before dielectric barrier discharge plasma treatment was -14.6 mV, and the Zeta potential value of the powder after dielectric barrier discharge plasma treatment was -17.5 mV, with a Zeta potential difference of 2.9 mV.

[0074] In Example 1, the voltage amplitude V is 5 kV, the processing time is 10 minutes, and Δζ = 0.01356 V is used. 1.8107 ·T 1.0798 The calculated Δζ is 3.00389mV.

[0075] Example 2

[0076] (1) A sealed vacuum chamber 11 is provided. The sealed vacuum chamber 11 contains an upper electrode 22, a lower electrode 23, an upper insulating dielectric plate 12, a lower insulating dielectric plate 13, and a support member 14. The upper electrode 22 and the lower electrode 23 are both mounted on the support member 14 and connected to an AC power supply 21. The upper insulating dielectric plate 12 is connected to the upper electrode 22, and the lower insulating dielectric plate 13 is connected to the lower electrode 23. The upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 are spaced apart and opposite to each other, and are located between the upper electrode 22 and the lower electrode 23. The air gap width between the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 is 3 mm. Both the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 are alumina plates.

[0077] (2) Select ceramic sintered powder with a particle size of 10-20 nanometers and dry it. Among them, the ceramic sintered powder in Example 2 is high-purity zinc oxide nanoparticles.

[0078] (3) The dried high-purity zinc oxide nanopowder is evenly spread on a 50 mm × 50 mm × 1 mm lower insulating dielectric plate 13. The thickness of the high-purity zinc oxide nanopowder spread on the lower insulating dielectric plate 13 is 0.5 mm.

[0079] (4) Adjust the atmosphere inside the sealed vacuum chamber 11 to an argon atmosphere of 0.5 atm.

[0080] (5) When the AC power supply 21 is turned on, the upper electrode 22 and the lower electrode 23 generate dielectric barrier discharge plasma between the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 under the action of the AC power supply 21. The voltage frequency of the AC power supply is 10 kHz and the voltage amplitude is 10 kV.

[0081] (6) High-purity zinc oxide nanoparticles were treated with dielectric barrier discharge plasma for 10 minutes.

[0082] (7) Turn off the power and collect the processed powder.

[0083] (8) Test the processed powder.

[0084] The specific surface area of ​​the ceramic sintered powder before and after treatment was tested using a BET specific surface area analyzer. The test results showed that the specific surface area of ​​the ceramic sintered powder before treatment was 22.835 m². 2 g -1 The specific surface area of ​​the ceramic sintered powder treated with dielectric barrier discharge plasma is 27.681 m². 2 g -1 Therefore, it can be seen that the specific surface area of ​​the ceramic sintered powder treated with dielectric barrier discharge plasma increased by 21.22% compared with the untreated ceramic sintered powder.

[0085] The dispersibility of ceramic sintered powder before and after treatment was characterized by measuring the Zeta potential. Specifically, the ceramic sintered powder was dispersed in anhydrous ethanol, the pH was adjusted with sodium hydroxide, and after magnetic stirring and ultrasonic dispersion at room temperature, the Zeta potential values ​​of the powder before and after dielectric barrier discharge plasma treatment were measured using a NanoZS Zeta potential meter. The Zeta potential value of the powder before dielectric barrier discharge plasma treatment was -13.4 mV, and the Zeta potential value of the powder after dielectric barrier discharge plasma treatment was -24 mV, with a Zeta potential difference of 10.6 mV.

[0086] In Example 2, the voltage amplitude V is 10 kV, the processing time is 10 minutes, and Δζ = 0.01356 V is used. 1.8107 ·T 1.0798 The calculated Δζ is 10.53803mV.

[0087] Example 3

[0088] (1) A sealed vacuum chamber 11 is provided. The sealed vacuum chamber 11 contains an upper electrode 22, a lower electrode 23, an upper insulating dielectric plate 12, a lower insulating dielectric plate 13, and a support member 14. The upper electrode 22 and the lower electrode 23 are both mounted on the support member 14 and connected to an AC power supply 21. The upper insulating dielectric plate 12 is connected to the upper electrode 22, and the lower insulating dielectric plate 13 is connected to the lower electrode 23. The upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 are spaced apart and opposite to each other, and are located between the upper electrode 22 and the lower electrode 23. The air gap width between the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 is 3 mm. Both the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 are alumina plates.

[0089] (2) Select ceramic sintered powder with a particle size of 10-20 nanometers and dry it. Among them, the ceramic sintered powder in Example 3 is high-purity zinc oxide nanoparticles.

[0090] (3) The dried high-purity zinc oxide nanopowder is evenly spread on a 50 mm × 50 mm × 1 mm lower insulating dielectric plate 13. The thickness of the high-purity zinc oxide nanopowder spread on the lower insulating dielectric plate 13 is 0.5 mm.

[0091] (4) Adjust the atmosphere inside the sealed vacuum chamber 11 to an argon atmosphere of 0.5 atm.

[0092] (5) When the AC power supply 21 is turned on, the upper electrode 22 and the lower electrode 23 generate dielectric barrier discharge plasma between the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 under the action of the AC power supply 21. The voltage frequency of the AC power supply is 10 kHz and the voltage amplitude is 5 kV.

[0093] (6) High-purity zinc oxide nanoparticles were treated with dielectric barrier discharge plasma for 30 minutes.

[0094] (7) Turn off the power and collect the processed powder.

[0095] (8) Test the processed powder.

[0096] The specific surface area of ​​the ceramic sintered powder before and after treatment was tested using a BET specific surface area analyzer. The test results showed that the specific surface area of ​​the ceramic sintered powder before treatment was 23.102 m². 2 g -1 The specific surface area of ​​the ceramic sintered powder treated with dielectric barrier discharge plasma is 31.397 m². 2 g -1 Therefore, the specific surface area of ​​the ceramic sintered powder treated with dielectric barrier discharge plasma increased by 35.91% compared with that of the untreated ceramic sintered powder.

[0097] The dispersibility of ceramic sintered powder before and after treatment was characterized by measuring the Zeta potential. Specifically, the ceramic sintered powder was dispersed in anhydrous ethanol, the pH was adjusted with sodium hydroxide, and after magnetic stirring and ultrasonic dispersion at room temperature, the Zeta potential values ​​of the powder before and after dielectric barrier discharge plasma treatment were measured using a NanoZS Zeta potential meter. The Zeta potential value of the powder before dielectric barrier discharge plasma treatment was -13.3 mV, and the Zeta potential value of the powder after dielectric barrier discharge plasma treatment was -23.2 mV, with a Zeta potential difference of 9.9 mV.

[0098] In Example 3, the voltage amplitude V is 5 kV, the processing time is 30 minutes, and Δζ = 0.01356 V is used. 1.8107 ·T 1.0798 The calculated Δζ is 9.83740mV.

[0099] Example 4

[0100] (1) A sealed vacuum chamber 11 is provided. The sealed vacuum chamber 11 contains an upper electrode 22, a lower electrode 23, an upper insulating dielectric plate 12, a lower insulating dielectric plate 13, and a support member 14. The upper electrode 22 and the lower electrode 23 are both mounted on the support member 14 and connected to an AC power supply 21. The upper insulating dielectric plate 12 is connected to the upper electrode 22, and the lower insulating dielectric plate 13 is connected to the lower electrode 23. The upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 are spaced apart and opposite to each other, and are located between the upper electrode 22 and the lower electrode 23. The air gap width between the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 is 3 mm. Both the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 are alumina plates.

[0101] (2) Select ceramic sintered powder with a particle size of 10-20 nanometers and dry it. Among them, the ceramic sintered powder in Example 4 is high-purity zinc oxide nanoparticles.

[0102] (3) The dried high-purity zinc oxide nanopowder is evenly spread on a 50 mm × 50 mm × 1 mm lower insulating dielectric plate 13. The thickness of the high-purity zinc oxide nanopowder spread on the lower insulating dielectric plate 13 is 0.5 mm.

[0103] (4) Adjust the atmosphere inside the sealed vacuum chamber 11 to an argon atmosphere of 0.5 atm.

[0104] (5) When the AC power supply 21 is turned on, the upper electrode 22 and the lower electrode 23 generate dielectric barrier discharge plasma between the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 under the action of the AC power supply 21. The voltage frequency of the AC power supply is 10 kHz and the voltage amplitude is 10 kV.

[0105] (6) High-purity zinc oxide nanoparticles were treated with dielectric barrier discharge plasma for 30 minutes.

[0106] (7) Turn off the power and collect the processed powder.

[0107] (8) Test the processed powder.

[0108] The specific surface area of ​​the ceramic sintered powder before and after treatment was tested using a BET specific surface area analyzer. The test results showed that the specific surface area of ​​the ceramic sintered powder before treatment was 23.264 m². 2 g -1 The specific surface area of ​​the ceramic sintered powder treated with dielectric barrier discharge plasma is 32.093 m². 2 g -1 Therefore, it can be seen that the specific surface area of ​​the ceramic sintered powder treated with dielectric barrier discharge plasma increased by 37.95% compared with the untreated ceramic sintered powder.

[0109] The dispersibility of ceramic sintered powder before and after treatment was characterized by measuring the Zeta potential. Specifically, the ceramic sintered powder was dispersed in anhydrous ethanol, the pH was adjusted with sodium hydroxide, and after magnetic stirring and ultrasonic dispersion at room temperature, the Zeta potential values ​​of the powder before and after dielectric barrier discharge plasma treatment were measured using a NanoZS Zeta potential meter. The Zeta potential value of the powder before dielectric barrier discharge plasma treatment was -14.2 mV, and the Zeta potential value of the powder after dielectric barrier discharge plasma treatment was -48.8 mV, with a Zeta potential difference of 34.6 mV.

[0110] In Example 4, the voltage amplitude V is 5 kV, the processing time is 10 minutes, and Δζ = 0.01356 V is used. 1.8107 ·T 1.0798 The calculated Δζ is 34.51082mV.

[0111] Table 1 shows the processing conditions of the ceramic sintered powder and the test data before and after processing in each embodiment.

[0112]

[0113] Based on Examples 1-4, measurements of specific surface area and Zeta potential show that treating ceramic sintered powder with dielectric barrier discharge plasma can effectively improve the dispersion performance of the ceramic powder. Furthermore, the improvement effect of dielectric barrier discharge plasma treatment on the dispersion of ceramic sintered powder increases with increasing voltage amplitude and treatment time. Specifically, the Zeta potential difference between the powder before and after dielectric barrier discharge plasma treatment is 2.9mV-35mV, and the specific surface area of ​​the ceramic sintered powder treated with dielectric barrier discharge plasma is increased by 14%-40% compared to the untreated ceramic sintered powder.

[0114] See Figure 2 This application also provides an apparatus 100 for improving the dispersibility of ceramic sintered powder, including a sealed vacuum chamber 11, an AC power supply 21, a vacuum pump 31, and a gas cylinder 32. The sealed vacuum chamber 11 is equipped with an upper electrode 23, a lower electrode 24, an upper insulating dielectric plate 12, and a lower insulating dielectric plate 13. The upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 are spaced apart and opposite to each other, and the lower insulating dielectric plate 13 is used to lay the ceramic sintered powder. The upper electrode 22 is connected to the upper insulating dielectric plate 12, and the lower electrode 23 is connected to the lower insulating dielectric plate 13. Both the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 are located between the upper electrode 22 and the lower electrode 23. The upper electrode 22 and the lower electrode 23 are respectively connected to the AC power supply 21. The vacuum pump 31 is connected to the sealed vacuum chamber 11; the gas cylinder 32 stores inert gas and is connected to the sealed vacuum chamber 11. The vacuum pump 31 and the gas cylinder 32 are used together to control the atmosphere inside the sealed vacuum chamber 11.

[0115] In some embodiments, the apparatus 100 for improving the dispersibility of ceramic sintered powder further includes a support 14, which is installed inside a sealed vacuum chamber 11, and the upper electrode 23 and the lower electrode 24 are fixed to the support 14. The support 14 can also be used to adjust the relative position between the upper electrode 23 and the lower electrode 24, thereby adjusting the air gap width between the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13.

[0116] In some embodiments, the air gap width between the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 is 2 mm to 4 mm.

[0117] Of course, in some other embodiments, the support member 14 may be omitted.

[0118] In some embodiments, the device 100 for improving the dispersibility of ceramic sintered powder further includes two conductive pillars 22, each connected to an AC power supply 21. The conductive pillars 22 are disposed within a sealed vacuum chamber 11 and pass through the chamber. An upper electrode 23 is disposed between an upper insulating dielectric plate 12 and one conductive pillar 22 and connected in series with both. A lower electrode 24 is disposed between a lower insulating dielectric plate 13 and another conductive pillar 22 and connected in series with both. The AC power supply 21 is connected to the upper insulating dielectric plate 12 and the lower insulating dielectric plate 13 through the upper and lower electrodes, respectively. When the AC power supply 21 is turned on, an AC voltage is applied between the upper electrode 22 and the lower electrode 23, causing dielectric barrier discharge plasma to be generated between the upper insulating dielectric plates 12 and the lower insulating dielectric plate 13.

[0119] In some embodiments, the device 100 for improving the dispersibility of ceramic sintered powder further includes a pressure gauge 34 and two gas valves 33. The two gas valves 33 are respectively located on the pipe connecting the sealed vacuum chamber 11 to the vacuum pump 31 and on the pipe connecting the sealed vacuum chamber 11 to the gas cylinder 32, for controlling the opening and closing of the two connecting pipes and adjusting the gas pressure and the amount of inert gas injected into the sealed vacuum chamber 11. The pressure gauge 34 is connected to the sealed vacuum chamber 11 to display the gas pressure inside the sealed vacuum chamber 11, facilitating the control of the atmosphere inside the sealed vacuum chamber 11.

[0120] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.

Claims

1. A method for improving the dispersibility of sintered ceramic powder, characterized in that, The ceramic sintering powder is used for sintering to prepare ceramics, and the method includes: A sealed vacuum chamber is provided, wherein an upper electrode, a lower electrode, an upper insulating dielectric plate, and a lower insulating dielectric plate are disposed inside the sealed vacuum chamber. The upper insulating dielectric plate and the lower insulating dielectric plate are spaced apart and arranged opposite to each other. The upper electrode is connected to the upper insulating dielectric plate, and the lower electrode is connected to the lower insulating dielectric plate. The upper insulating dielectric plate and the lower insulating dielectric plate are both located between the upper electrode and the lower electrode. The upper electrode and the lower electrode are respectively connected to an AC power supply. Ceramic sintered powder is laid on the lower insulating dielectric plate, and the ceramic sintered powder is located between the upper insulating dielectric plate and the lower insulating dielectric plate; The atmosphere inside the sealed vacuum chamber is controlled, and the atmosphere of the sealed vacuum chamber is adjusted to an inert atmosphere of 0.2 atm-1 atm; When the AC power supply is turned on, and the voltage frequency of the AC power supply is adjusted to 8 kHz-12 kHz, and the voltage amplitude is 5 kV-15 kV, the upper electrode and the lower electrode, under the action of the AC power supply, generate dielectric barrier discharge plasma between the upper insulating dielectric plate and the lower insulating dielectric plate; and The ceramic sintered powder is treated with the dielectric barrier discharge plasma for a certain period of time. The dielectric barrier discharge plasma processes the ceramic sintered powder for 10 to 30 minutes.

2. The method for improving the dispersibility of ceramic sintered powder according to claim 1, characterized in that, In the step of laying the ceramic sintered powder on the lower insulating dielectric plate, the ceramic sintered powder is a high-purity nanoparticle with a particle size of 10 nanometers to 20 nanometers.

3. The method for improving the dispersibility of ceramic sintered powder according to claim 1, characterized in that, In the step of laying the ceramic sintered powder on the lower insulating dielectric plate, the ceramic sintered powder is evenly spread on the lower insulating dielectric plate, and the thickness of the ceramic sintered powder is 0.2 mm to 1 mm.

4. The method for improving the dispersibility of ceramic sintered powder according to claim 1, characterized in that, The change in Zeta potential of the ceramic sintered powder before and after dielectric barrier discharge plasma treatment is related to the voltage amplitude and treatment time as follows: Δζ = 0.01356 V 1.8107 ·T 1.0798 Wherein, Δζ is the Zeta potential difference of the ceramic sintered powder before and after treatment with the dielectric barrier discharge plasma, in millivolts; V is the voltage amplitude of the AC power supply, in kilovolts; and T is the treatment time of the ceramic sintered powder by the dielectric barrier discharge plasma, in minutes.

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