Glass powder particle for electrostatic spraying of resistor disc as well as preparation method and application of glass powder particle

Abstract

The invention relates to the technical field of electronic components, and particularly discloses a glass powder particle for electrostatic spraying of a resistor disc and a preparation method and application thereof.The glass powder particle is composed of silicon oxide, boron oxide and other raw materials in specific parts by weight, the sphericity degree after granulation is larger than or equal to 90%, the powder particle D50 is 40-50 microns, and the surface of the glass powder particle is coated with a silicon nitride layer and a functional layer; the invention further provides a preparation method and application steps in a resistor disc electrostatic spraying process. The glass powder particle suitable for electrostatic spraying of the resistor disc is prepared, the good process effect and performance can be guaranteed in the electrostatic spraying and sintering process, and the preparation method is high in operability.

Description

Technical Field

[0001] The present application relates to the technical field of electronic components, and more specifically, to a glass powder particle for electrostatic spraying of resistor sheets, a preparation method and an application thereof. Background Art

[0002] In an era of rapid development of electronic devices, resistors, as essential components, have a performance that directly impacts the overall quality and stability of these devices. As electronic devices continue to move towards miniaturization and higher performance, the quality and performance requirements for resistors are becoming increasingly stringent. Glass powder particles play a crucial role in resistor manufacturing, with their performance directly impacting the resistor's electrical, mechanical, and stability performance. High-quality glass powder particles can significantly improve the resistor's insulation, corrosion resistance, and aging resistance, effectively extending its service life and ensuring stable operation of electronic devices. In particular, the quality of glass powder particles plays a crucial role in the electrostatic spraying process for resistors, directly affecting the spraying results and the resistor's ultimate performance. Therefore, improving the quality and performance of glass powder particles is crucial to meeting the ever-increasing demands of electronic devices.

[0003] In existing technologies, the production process for glass powder particles often struggles to precisely control key parameters such as particle size distribution, particle shape, and surface properties. This results in unstable performance and significant batch-to-batch variability. This not only affects the uniformity and adhesion of the resistor during electrostatic spraying, making it difficult to achieve ideal spraying results, but also further restricts improvements in the resistor's electrical, mechanical, and stability performance, making it impossible to fully meet the stringent quality and performance requirements of the resistor required by the trend toward miniaturization and high performance in electronic devices.

[0004] Therefore, it is necessary to prepare a glass powder suitable for electrostatic spraying for the preparation of resistor sheets. Summary of the Invention

[0005] In order to solve the above problems, the present application provides a glass powder for electrostatic spraying of resistor sheets, a preparation method and its application In a first aspect, the present application provides a glass powder for electrostatic spraying of resistor sheets, using the following technical solution: A glass powder for electrostatic spraying of resistor sheets, comprising the following raw materials in parts by weight: 40-60 parts of silicon oxide, 10-20 parts of boron oxide, 5-15 parts of lead oxide, 3-8 parts of aluminum oxide, 2-6 parts of zinc oxide, 1-4 parts of titanium oxide, 0.5-2 parts of copper oxide, and 0.1-1 parts of cobalt oxide are added with a binder to granulate the above raw materials to obtain glass powder particles, which are applied to the glass glaze electrostatic spraying process. The sphericity of the glass powder particles is ≥90%, and the powder particles D50 40-50μm.

[0006] By adopting the above technical solution, silicon oxide and boron oxide are precisely blended to ensure glass-forming ability and reduce melting temperature. Lead oxide significantly improves the wettability, fluidity, and surface tension of the molten glass during electrostatic spraying, ensuring a uniform, dense, and highly adherent coating. Aluminum oxide and zinc oxide effectively enhance the coating's hardness, mechanical strength, and thermal stability, improving weather resistance. The addition of an appropriate amount of titanium oxide fine-tunes the dielectric constant and improves compatibility with the substrate electrode. The key additions of trace amounts of copper oxide and cobalt oxide act synergistically to regulate the glass's resistive properties and thermal expansion coefficient, working together with the main lead oxide to ensure that the electrical properties of the final sintered coating precisely meet the technical requirements of the resistor. This composite formula ultimately ensures low-temperature, efficient sintering while significantly improving the coating's uniformity, density, adhesion strength, electrical performance consistency, and long-term reliability, comprehensively optimizing resistor production efficiency and product quality.

[0007] Granulating glass powder can reduce friction with the inner wall of the spray gun during electrostatic spraying, reduce charge loss, and ensure uniform force in the electric field to avoid agglomeration. Its highly regular spherical structure and precise particle size control ensure that the powder obtains uniform and sufficient charge distribution in the electrostatic field, ensuring that the powder moves in a laminar state in the electric field, avoiding local accumulation caused by turbulence, greatly improving the spray transmission efficiency and deposition uniformity, reducing spray gun blockage and dust, and obtaining a more uniform and dense glass glaze layer, thereby improving the overall performance of the resistor.

[0008] Optionally, the binder is a 6-10 wt % polyvinyl alcohol aqueous solution, and the ratio of the added amount of the binder to the added amount of the glass powder particles is 1:16-20.

[0009] Optionally, the surface of the glass powder particles is coated with a silicon nitride layer and a functional layer, the thickness of the silicon nitride layer is 30-50 nm; the functional layer is obtained by atomizing and wrapping a functional layer wrapping solution, which contains a fluorosilicone polymer ethanol solution and a cerium oxide sol.

[0010] By adopting the above-mentioned technical solution and further coating the surface, the process stability and functional properties of the electrostatic spraying of glass glaze are significantly improved. The nano-silicon nitride layer acts as a high-hardness insulating skeleton to enhance the mechanical strength of the particles and optimize the interfacial bonding with the glaze matrix. The fluorosilicone polymer reduces the surface energy, giving the powder excellent anti-hygroscopicity and fluidity to adapt to environmental humidity fluctuations. It also acts as a lubricating layer that decomposes at high temperatures, promoting orderly melting and spreading between particles during the initial sintering process, eliminating bubbles and pinholes. The mesoporous cerium oxide coating plays a dual role: it uses its high surface area to adsorb organic impurities and purify the sintering environment. It also acts as an active oxygen buffer to passivate oxygen defects at the electrode interface at high temperatures, significantly inhibiting the electrochemical aging of the coating. The composite coating structure synergistically achieves comprehensive improvements in powder fluidity, bulk density, high-temperature wettability, and interfacial electrochemical stability. Ultimately, the sprayed glaze layer is ultra-thin, dense, defect-free, with high insulation strength and anti-aging properties, directly improving the long-term service reliability of the resistor.

[0011] Optionally, the weight ratio of the functional layer coating solution to the glass powder is 5-9:100; the weight ratio of the fluorosilicone polymer ethanol solution to the cerium oxide sol in the functional layer coating solution is 1:8-10.

[0012] By adopting the above technical solution, fluorosilicone polymers decompose during high-temperature melting to produce gaseous small molecules, which promote the rearrangement of glass particles, reduce melt viscosity, and form an instantaneous air cushion layer to achieve high-temperature melting densification. At the same time, the directional arrangement of its perfluoroalkyl chains precisely controls the surface energy of the powder, ensuring uniform distribution of electrostatic spraying charges and low moisture content under environmental humidity fluctuations; mesoporous cerium oxide absorbs organic volatiles released during sintering by virtue of the mesopore confinement capture mechanism to avoid insulation degradation, and releases active oxygen ions during the cooling period of the glaze layer through the oxygen vacancy self-healing mechanism, neutralizing electrode migration ions and filling the oxygen defect sites in the glass network to achieve electrochemical interface passivation; the two ratios synergistically produce an amplifying effect, the fluorosilicone polymer decomposition gas opens the cerium oxide pores to improve adsorption efficiency, and the mesoporous cerium oxide adsorbs impurities to reduce the activation energy of fluorosilicone polymer decomposition, ultimately achieving multiple breakthrough improvements such as extremely low glaze porosity, small surface roughness, low dielectric loss, and a significant decrease in dendrite density at ultra-low addition amounts.

[0013] Optionally, the fluorosilicone polymer is heptadecafluorodecyltriethoxysilane.

[0014] By adopting the above technical solution, the perfluoroalkyl chains form a dense arrangement, which can greatly reduce the surface energy of the powder, improve the static water contact angle, reduce the moisture content of the powder, eliminate the adverse phenomena in electrostatic spraying, and significantly improve the yield; the ethoxyl group hydrolyzes and condenses to firmly bond with the powder surface, and precisely thermally decomposes in the sintering window, releasing gaseous substances to reduce the viscosity of the molten glass, eliminate micro-porosity, optimize the glaze roughness and improve the gloss; the decomposition products are completely vaporized and dissipated to avoid the risk of organic carbon residues, and the fluorine-containing gas forms an F⁻ ion barrier to inhibit the migration of electrode metal ions, stabilize the insulation strength and extend the aging life of high-voltage electricity, thereby comprehensively improving the performance and quality of the product.

[0015] Optionally, the mesopore diameter of the cerium oxide is 5-15 nm, and the specific surface area is ≥200 m 2 / g.

[0016] By adopting the above technical solution, the mesoporous channels with specific pore sizes can act like a precise sieve, efficiently capturing organic volatiles released during the sintering process that match the pore size through the capillary condensation effect. The ultra-high specific surface area provides a large number of adsorption sites, greatly improving the adsorption capacity, effectively purifying the sintering atmosphere, eliminating glaze bubbles, and stabilizing the breakdown voltage. The specific crystal faces exposed by the high specific surface area bring high-concentration surface oxygen vacancies, which release active oxygen during sintering, which can not only neutralize the electrode migration ions and inhibit the growth of metal dendrites, but also fill the oxygen defect sites in the glaze layer and reduce dielectric loss. The appropriate pore size ensures the rapid diffusion of oxygen ions to achieve local defect repair. The nano-confinement effect of the mesoporous skeleton reduces the phase change threshold of cerium oxide, causing it to undergo dynamic valence state conversion during the glaze melting stage, buffering thermal stress by releasing or absorbing lattice oxygen, adaptively matching the thermal expansion difference of the glaze-electrode interface, effectively inhibiting the initiation of microcracks, and comprehensively improving the performance and reliability of the material.

[0017] In a second aspect, the present application provides a method for preparing glass powder particles for electrostatic spraying of resistor sheets, using the following technical solution: A method for preparing glass powder particles for electrostatic spraying of resistor sheets comprises the following steps: (1) Mix the raw materials according to the mixing ratio, melt them at 1450-1550℃, keep them warm for 2-3 hours, take them out, quench them with water, crush them, and ball mill them to obtain basic glass powder; (2) The basic glass powder is granulated to obtain glass powder particles, and a mixture of silane and ammonia with a volume ratio of 1:1.5-2 is introduced to deposit a 30-50 nm thick silicon nitride layer on its surface by plasma. After the deposition is completed, the functional layer coating solution is atomized and evenly coated on the powder surface, and sieved to obtain glass powder particles coated with the functional layer.

[0018] By adopting the above technical solution, through the precise coordination of high-temperature melting water quenching and plasma activation-in-situ composite coating, the glass network is first completely depolymerized by melting at 1450-1550°C, and high-energy metastable glass is obtained by water quenching, which inhibits crystallization and avoids glaze cracking, thereby optimizing the activity of the basic powder; radio frequency plasma is then used to dissociate silane and ammonia into free radicals, which react with the glass surface to form a covalently bonded Si-N-Si network, precisely controlling the thickness of the deposited layer, and improving the breakdown field strength, interfacial binding energy and particle compressive strength; finally, the fluorosilane ethanol solution and cerium oxide sol are atomized, and the fluorosilane self-assembles into a continuous hydrophobic film. The mesoporous cerium oxide sol is electrostatically adsorbed and anchored on the outside with unobstructed pores, and simultaneous screening is used to achieve particle size control, further improving the anti-aging properties and surface activity of the glass powder, and finally, glass powder particles coated with a functional layer are obtained after screening.

[0019] Optionally, in step (2), the volume ratio of NH3 and SiH4 is controlled to be 1:1.5-2, and the deposition time is 10-15 min; and the pressure applied during atomization in step (2) is 0.7-0.9 MPa.

[0020] By adopting the above technical solution, silane and ammonia are fully reacted in a plasma environment to generate a silicon nitride layer with stable chemical properties and dense structure, effectively avoiding uneven silicon nitride composition or structural defects caused by proportion imbalance, thereby ensuring that the silicon nitride layer plays an excellent protective role for the basic glass powder and enhancing its corrosion and oxidation resistance. At the same time, the deposition time is set to 10-15 minutes, and while ensuring that the silicon nitride layer thickness reaches the ideal range of 30-50nm, it avoids resource waste and interlayer stress problems caused by excessive deposition. In addition, the atomization pressure is controlled at 0.7-0.9MPa. This pressure range allows the ethanol solution of the fluorine-containing silicon polymer and the cerium oxide sol to be fully atomized into uniform and fine droplets, which are evenly wrapped on the powder surface with just the right force to form a complete, dense and uniform functional layer, comprehensively improving the overall performance of the glass powder and making it exhibit higher stability and reliability in subsequent applications.

[0021] In a third aspect, a method for applying glass powder particles for electrostatic spraying of a resistor sheet in a resistor sheet electrostatic spraying process is provided, wherein the method comprises the following steps: (a) Applying a high voltage of 55-65 kV, electrostatically spraying glass powder onto the side of the resistor preheated to 150-160 ° C to form a 90-110 μm powder deposition layer; (b) A pulsed infrared laser with a wavelength of 1064 nm and a power density of 30-40 W / cm² is used to scan and sinter the powder deposition layer at a speed of 0.5-2 m / s; during laser sintering, the local temperature gradient is controlled to be ≤200°C / mm.

[0022] In summary, this application has the following beneficial effects: 1. This application forms a composite formula by precisely blending basic ingredients such as silicon oxide, boron oxide, and lead oxide, and adding auxiliary ingredients such as aluminum oxide, zinc oxide, titanium oxide, copper oxide, and cobalt oxide. This formula not only ensures the glass-forming ability and low-temperature, high-efficiency sintering characteristics, but also significantly improves the uniformity, density, adhesion strength, electrical performance consistency, and long-term reliability of the coating. Lead oxide improves the wettability and fluidity of the slurry, ensuring the formation of a uniform and dense coating during electrostatic spraying; aluminum oxide and zinc oxide enhance the hardness and mechanical strength of the coating; titanium oxide fine-tunes the dielectric constant and improves compatibility with the substrate electrode; copper oxide and cobalt oxide synergistically regulate the resistance characteristics and thermal expansion coefficient of the glass. The synergistic effect of these ingredients enables the final sintered coating to accurately meet the technical requirements of the resistor, comprehensively optimizing the production efficiency and product quality of the resistor.

[0023] 2. In this application, a silicon nitride layer and a functional layer are coated on the surface of glass powder particles. The nano-silicon nitride layer enhances the mechanical strength of the particles and optimizes interfacial bonding. The fluorosilicone polymer imparts hygroscopic resistance and fluidity to the powder, promoting particle melt and spreading during the initial sintering process, eliminating bubbles and pinholes. The mesoporous cerium oxide adsorbs organic impurities, passivates oxygen defects at the electrode interface, and inhibits electrochemical aging of the coating. This composite coating structure synergistically improves the powder's fluidity, bulk density, high-temperature wettability, and interfacial electrochemical stability, resulting in an ultra-thin, dense, defect-free spray glaze layer with high dielectric strength and aging resistance, directly enhancing the long-term service reliability of the resistor.

[0024] 3. This method utilizes electrostatic spraying and pulsed infrared laser sintering with specific parameters. Applying a high voltage of 55-65kV, glass powder particles are sprayed onto the sides of the preheated resistor, forming a powder deposit of appropriate thickness. This is then scanned and sintered at a specific wavelength, power density, and speed, while controlling the local temperature gradient. This precise, coordinated process reduces spray gun clogging and dust generation, resulting in a more uniform and dense glass glaze layer and improving the overall performance of the resistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a typical feature of the particle morphology of the granulated glass powder particles of Example 4 under a microscope; Figure 2 These are typical features of the particle morphology of the glass powder prepared in Comparative Example 1 under a microscope. DETAILED DESCRIPTION

[0026] The present application is further described in detail below with reference to the examples. It is particularly noted that if no specific conditions are specified in the following examples, the reactions are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0027] Fluorosilicone polymer was purchased from Guangdong Zhongke Hongtai New Materials Co., Ltd., model: B-334; the resistor was D42 zinc oxide resistor purchased from Shanghai Beiyuan Industry and Trade Co., Ltd.

[0028] Preparation examples of raw materials and / or intermediates Preparation Example 1 A functional layer coating solution, the preparation of which comprises the following steps: Prepare an ethanol solution of a fluorosilicone polymer by dissolving heptadecafluorodecyltriethoxysilane (fluorosilicone polymer) in anhydrous ethanol at a mass fraction of 10%, and stir in a 50°C water bath for 2 hours to fully dissolve the fluorosilicone polymer to obtain an ethanol solution of the fluorosilicone polymer; Prepare cerium oxide sol: dissolve cerium nitrate hexahydrate in deionized water, add an appropriate amount of ammonia water to adjust the pH value to 9-10, stir at 60°C for 4 hours to carry out hydrolysis and polycondensation reaction, and obtain cerium oxide sol; 1 kg of ethanol solution of fluorinated silicone polymer was mixed with 9 kg of cerium oxide sol, and then ultrasonically treated in an ultrasonic cleaner for 30 minutes to fully mix the two solutions to obtain a functional layer coating solution.

[0029] Preparation Example 2 A functional layer coating solution is prepared, which is different from Preparation Example 1 in that 1 kg of ethanol solution of fluorinated silicon polymer is mixed with 8 kg of cerium oxide sol, and the remaining steps are the same as Preparation Example 1.

[0030] Preparation Example 3 A functional layer coating solution is prepared, which is different from Preparation Example 1 in that 1 kg of ethanol solution of fluorinated silicon polymer is mixed with 10 kg of cerium oxide sol, and the remaining steps are the same as Preparation Example 1.

[0031] Example

[0032] Example 1

[0033] A glass powder for electrostatic spraying of resistor sheets is prepared by the following steps: (1) Weigh 50 kg of silicon oxide, 15 kg of boron oxide, 5 kg of lead oxide, 5 kg of aluminum oxide, 4 kg of zinc oxide, 2 kg of titanium oxide, 1 kg of copper oxide, and 0.5 kg of cobalt oxide, mix them evenly, transfer them to a high-temperature furnace, melt them at 1500 °C, keep them warm for 2 h, and quench them with water. After quenching, crush the glass particles and grind them in a ball mill. Use aluminum oxide balls as the ball milling medium and mill them for 4 h to obtain basic glass powder. (2) After drying 54 kg of basic glass powder at 100 ° C for 5 hours, put it into a granulator for granulation. During granulation, 3 kg of 8 wt% polyvinyl alcohol aqueous solution was sprayed into it. At the same time, the speed of the granulator was controlled at 300 r / min and the granulation time was 15 minutes. The powder D with sphericity ≥ 90% was obtained. 50 The glass powder particles are 40-50μm.

[0034] Example 2

[0035] A glass powder for electrostatic spraying of resistor sheets is prepared by the following steps: (1) Weigh 40 kg of silicon oxide, 20 kg of boron oxide, 15 kg of lead oxide, 3 kg of aluminum oxide, 6 kg of zinc oxide, 4 kg of titanium oxide, 0.5 kg of copper oxide, and 1 kg of cobalt oxide, mix them evenly, transfer them to a high-temperature furnace, melt them at 1450 ° C, keep them warm for 3 hours, and then quench them with water. The quenched glass particles are initially crushed and then put into a ball mill for fine grinding. Alumina balls are used as the ball milling medium. The ball milling is carried out for 4 hours to obtain basic glass powder. (2) After drying 48 kg of basic glass powder at 100 ° C for 5 hours, put it into a granulator for granulation. During granulation, 3 kg of 8 wt% polyvinyl alcohol aqueous solution was sprayed into it. At the same time, the speed of the granulator was controlled at 300 r / min and the granulation time was 15 minutes. The powder D with sphericity ≥ 90% was obtained. 50 The glass powder particles are 40-50μm.

[0036] Example 3

[0037] A glass powder for electrostatic spraying of resistor sheets is prepared by the following steps: (1) Weigh 60 kg of silicon oxide, 10 kg of boron oxide, 10 kg of lead oxide, 8 kg of aluminum oxide, 2 kg of zinc oxide, 1 kg of titanium oxide, 2 kg of copper oxide, and 0.1 kg of cobalt oxide, mix them evenly, transfer them to a high-temperature furnace, melt them at 1550 ° C, keep them warm for 2 hours, and then quench them with water. The quenched glass particles are initially crushed and then put into a ball mill for fine grinding. Alumina balls are used as the ball milling medium. The ball milling is carried out for 4 hours to obtain basic glass powder. (2) After drying 60 kg of basic glass powder at 100 ° C for 5 hours, put it into a granulator for granulation. During granulation, 3 kg of 8 wt% polyvinyl alcohol aqueous solution was sprayed into it. At the same time, the speed of the granulator was controlled at 300 r / min and the granulation time was 15 minutes. The powder D with sphericity ≥ 90% was obtained. 50 The glass powder particles are 40-50μm.

[0038] Example 4

[0039] A glass powder for electrostatic spraying of a resistor, which differs from Example 1 in that the surface of the glass powder in this embodiment is coated with a silicon nitride layer and a functional layer, specifically includes the following steps: 50 kg of the glass powder prepared in Example 1 was placed in a plasma deposition device and evacuated to 0.01 MPa. A mixture of silane and ammonia was introduced into the device, and the volume ratio of NH3 / SiH4 was controlled to be 1:1.8. At the same time, the plasma generator frequency was 13.56 MHz, the power was 120 W, and the deposition time was 12 min. A 30-50 nm thick silicon nitride layer was formed on the surface of the base glass powder. After the deposition was completed, the silicon nitride-coated glass powder was taken out and dried for later use. The silicon nitride-coated glass powder was placed in a fluidized bed spray dryer, and nitrogen was introduced to fluidize the powder. 3.5 kg of the functional layer coating solution prepared in Preparation Example 1 was sprayed into the fluidized bed in the form of droplets at a pressure of 0.8 MPa. The spray rate was 10 mL / min, and the fluidized bed temperature was controlled to be 40 ° C. After stopping the spraying, the fluidization was continued for 10 min to solidify the coating layer. The glass powder was then sieved through a 325 mesh sieve to obtain glass powder coated with a silicon nitride layer and a functional layer. The particle morphology under the microscope was shown as follows: Figure 1 .

[0040] Example 5

[0041] A glass powder for electrostatic spraying of a resistor, which differs from Example 1 in that the surface of the glass powder in this embodiment is coated with a silicon nitride layer and a functional layer, specifically includes the following steps: 50 kg of the glass powder prepared in Example 1 was placed in a plasma deposition apparatus and evacuated to 0.01 MPa. A mixture of silane and ammonia was introduced into the apparatus, and the volume ratio of NH3 / SiH4 was controlled to be 1:1.5. At the same time, the plasma generator frequency was 13.56 MHz, the power was 100 W, and the deposition time was 15 min. A 30-50 nm thick silicon nitride layer was formed on the surface of the base glass powder. After the deposition was completed, the glass powder was taken out and dried for later use. The silicon nitride-coated glass powder was placed in a fluidized bed spray dryer, and nitrogen was introduced to fluidize the powder. 2.5 kg of the functional layer coating solution prepared in Preparation Example 1 was taken and sprayed into the fluidized bed in the form of droplets at a pressure of 0.7 MPa. The spray rate was 10 mL / min, and the fluidized bed temperature was controlled to 40°C. After stopping the spraying, the fluidization was continued for 10 min to solidify the coating layer, and then sieved through a 325 mesh sieve to obtain glass powder coated with a silicon nitride layer and a functional layer.

[0042] Example 6

[0043] A glass powder for electrostatic spraying of a resistor, which differs from Example 1 in that the surface of the glass powder in this embodiment is coated with a silicon nitride layer and a functional layer, specifically includes the following steps: 50 kg of the glass powder prepared in Example 1 was placed in a plasma deposition apparatus and evacuated to 0.01 MPa. A mixture of silane and ammonia was introduced into the apparatus, and the volume ratio of NH3 / SiH4 was controlled to be 1:2. At the same time, the plasma generator frequency was 13.56 MHz, the power was 150 W, and the deposition time was 10 min. A 30-50 nm thick silicon nitride layer was formed on the surface of the base glass powder. After the deposition was completed, the silicon nitride-coated glass powder was taken out and dried for later use. The silicon nitride-coated glass powder was placed in a fluidized bed spray dryer, and nitrogen was introduced to fluidize the powder. 4.5 kg of the functional layer coating solution prepared in Preparation Example 1 was taken and sprayed into the fluidized bed in the form of droplets at a pressure of 0.9 MPa. The spray rate was 10 mL / min, and the fluidized bed temperature was controlled to 40°C. After stopping the spraying, the fluidization was continued for 10 min to solidify the coating layer, and then sieved through a 325 mesh sieve to obtain glass powder coated with a silicon nitride layer and a functional layer.

[0044] Application Example 1 An application of glass powder particles for electrostatic spraying of a resistor sheet specifically includes the following steps: (a) Applying a high voltage of 60 kV, the glass powder prepared in Example 1 was electrostatically sprayed onto the side of a resistor preheated to 155° C. to form a 100 μm powder deposition layer; (b) A pulsed infrared laser with a wavelength of 1064 nm and a power density of 35 W / cm² was used to scan and sinter the powder deposition layer at a speed of 1 m / s. During laser sintering, the local temperature gradient was controlled to be ≤200°C / mm.

[0045] Application Example 2 An application of glass powder particles for electrostatic spraying of a resistor sheet specifically includes the following steps: (a) Applying a high voltage of 55 kV, the glass powder prepared in Example 2 was electrostatically sprayed onto the side of a resistor preheated to 160° C. to form a 90 μm powder deposition layer; (b) A pulsed infrared laser with a wavelength of 1064 nm and a power density of 30 W / cm² was used to scan and sinter the powder deposition layer at a speed of 2 m / s. During laser sintering, the local temperature gradient was controlled to be ≤200°C / mm.

[0046] Application Example 3 An application of glass powder particles for electrostatic spraying of a resistor sheet specifically includes the following steps: (a) Applying a high voltage of 65 kV, the glass powder prepared in Example 3 was electrostatically sprayed onto the side of a resistor preheated to 160° C. to form a 110 μm powder deposition layer; (b) A pulsed infrared laser with a wavelength of 1064 nm and a power density of 40 W / cm² was used to scan and sinter the powder deposition layer at a speed of 0.5 m / s. During laser sintering, the local temperature gradient was controlled to be ≤200°C / mm.

[0047] Application Examples 4-6 An application of glass powder particles for electrostatic spraying of a resistor is different from Application Example 1 in that the glass powders prepared in Examples 4-6 are used respectively.

[0048] Comparative Example Comparative Example 1 A glass powder for electrostatic spraying of resistor sheets is prepared by the following steps: Weigh 50kg of silicon oxide, 15kg of boron oxide, 5kg of lead oxide, 5kg of aluminum oxide, 4kg of zinc oxide, 2kg of titanium oxide, 1kg of copper oxide, and 0.5kg of cobalt oxide, mix them evenly, transfer them to a high-temperature furnace, melt them at 1500℃, keep them warm for 2h, and quench them with water. The quenched glass particles are initially crushed and then put into a ball mill for fine grinding. Alumina balls are used as the ball milling medium. The ball milling is carried out for 4h to obtain glass powder. The particle morphology under the microscope is shown in FIG. Figure 2 .

[0049] Comparative Application Example 1 An application of glass powder for electrostatic spraying of a resistor is different from Application Example 1 in that the glass powder prepared in Comparative Example 1 is used in this comparative application example.

[0050] Performance testing Insulation strength test: A high current impulse withstand test is conducted according to the method specified in GB / T11032-2020 standard, with a 4 / 10μs high current to detect the maximum withstand value of the impulse capability and the insulation strength; Aging test: According to the method specified in IEC60216-1-2013, the resistance change rate is measured after 1000 hours at 85℃ / 85%RH.

[0051] Table 1 Test data

[0052] Combining Application Examples 1-3 with Comparative Application Example 1 and Table 1, it can be seen that the various test data of Application Examples 1-3 are better than those of Comparative Application Example 1, indicating that the granulation process can significantly improve the sphericity and particle size uniformity of the glass powder, thereby improving the adsorption efficiency of electrostatic spraying, forming a dense and uniform glass glaze layer, and ultimately improving the insulation strength, high current withstand value and weather resistance of the resistor. The comprehensive performance is better than that of Comparative Application Example 1 without granulation.

[0053] Combining Application Examples 1-3 with Application Examples 4-6 and Table 1, it can be seen that the test data of Application Examples 4-6 are significantly better than those of Application Examples 1-3, indicating that the introduction of a silicon nitride layer and a composite functional layer on the surface of the powder particles after granulation, through the synergy of various aspects, ultimately achieves a triple protection mechanism of "physical insulation-dynamic lubrication-self-repairing", achieving long-term and high reliability of the resistor.

[0054] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A glass powder for electrostatic spraying of resistor sheets, characterized in that: It includes the following raw materials in parts by weight: 40-60 parts of silicon oxide, 10-20 parts of boron oxide, 5-15 parts of lead oxide, 3-8 parts of aluminum oxide, 2-6 parts of zinc oxide, 1-4 parts of titanium oxide, 0.5-2 parts of copper oxide, and 0.1-1 parts of cobalt oxide are added with a binder to granulate the above raw materials to obtain glass powder particles, which are applied to the glass glaze electrostatic spraying process. The sphericity of the glass powder particles is ≥90%, and the powder particles D 50 40-50μm.

2. The glass powder for electrostatic spraying of resistor sheets according to claim 1, characterized in that: The binder is a 6-10 wt% polyvinyl alcohol aqueous solution, and the ratio of the amount of the binder added to the amount of the glass powder added is 1:16-20.

3. The glass powder for electrostatic spraying of resistor sheets according to claim 1, characterized in that: The surface of the glass powder is coated with a silicon nitride layer and a functional layer, wherein the thickness of the silicon nitride layer is 30-50 nm; the functional layer is obtained by atomizing and coating a functional layer coating solution, which contains a fluorosilicone polymer ethanol solution and a cerium oxide sol.

4. The glass powder for electrostatic spraying of resistor sheets according to claim 3, characterized in that: The weight ratio of the functional layer coating solution to the glass powder particles is 5-9:100; the weight ratio of the fluorosilicone polymer ethanol solution to the cerium oxide sol in the functional layer coating solution is 1:8-10.

5. The glass powder for electrostatic spraying of resistor sheets according to claim 3, characterized in that: The fluorosilicone polymer is heptadecafluorodecyltriethoxysilane.

6. The glass powder for electrostatic spraying of resistor sheets according to claim 3, characterized in that: The mesopore diameter of the cerium oxide is 5-15 nm, and the specific surface area is ≥200 m 2 / g.

7. The method for preparing glass powder for electrostatic spraying of resistor sheets according to claim 3, characterized in that: The steps include: (1) Mix the raw materials according to the mixing ratio, melt them at 1450-1550℃, keep them warm for 2-3 hours, take them out, quench them with water, crush them, and ball mill them to obtain basic glass powder; (2) The basic glass powder is granulated to obtain glass powder particles, and a mixture of silane and ammonia with a volume ratio of 1:1.5-2 is introduced to deposit a 30-50 nm thick silicon nitride layer on its surface by plasma. After the deposition is completed, the functional layer coating solution is atomized and evenly coated on the powder surface, and sieved to obtain glass powder particles coated with the functional layer.

8. The method for preparing glass powder for electrostatic spraying of resistor sheets according to claim 7, characterized in that: In the step (2), the volume ratio of NH3 and SiH4 is controlled to be 1:1.5-2, and the deposition time is 10-15 min; the pressure applied during atomization in the step (2) is 0.7-0.9 MPa.

9. Application of glass powder for electrostatic spraying of resistor sheets in a resistor sheet electrostatic spraying process, characterized in that: Using the glass powder particles for electrostatic spraying of resistor sheets according to any one of claims 1 to 6 specifically comprises the following steps: (a) Applying a high voltage of 55-65 kV, electrostatically spraying glass powder onto the side of the resistor preheated to 150-160 ° C to form a 90-110 μm powder deposition layer; (b) A pulsed infrared laser with a wavelength of 1064 nm and a power density of 30-40 W / cm² is used to scan and sinter the powder deposition layer at a speed of 0.5-2 m / s; during laser sintering, the local temperature gradient is controlled to be ≤200°C / mm.

Images