Glass powder particles for electrostatic spraying of resistance elements, method of production and use thereof

Abstract

The application relates to the technical field of electronic components, and particularly discloses a glass powder particle for electrostatic spraying of a resistance sheet, a preparation method and application thereof, which is composed of specific proportions of raw materials such as silicon oxide and boron oxide, has a sphericity of greater than or equal to 90% after granulation, a powder particle D50 of 40-50 mu m, a surface coated with a silicon nitride layer and a functional layer, and a preparation method and application steps in an electrostatic spraying process of the resistance sheet are further provided. The application has the technical effects that the glass powder particle suitable for electrostatic spraying of the resistance sheet can be prepared, good process effects and performances can be ensured in the electrostatic spraying and sintering processes, and the preparation method has high operability.

Description

Technical Field

[0001] This application relates to the field of electronic component technology, and more specifically, to a glass powder for electrostatic spraying of resistor sheets, its preparation method, and its application. Background Technology

[0002] In an era of rapid advancements in electronic devices, resistors, as indispensable fundamental components, directly impact the overall quality and stability of these devices. As electronic devices continue to evolve towards miniaturization and high performance, the requirements for the quality and performance of resistors are becoming increasingly stringent. Glass powder plays a crucial role in resistor manufacturing, its performance directly affecting the electrical, mechanical, and stability properties of the resistor. High-quality glass powder can significantly improve the insulation performance, corrosion resistance, and aging resistance of resistors, effectively extending their lifespan and ensuring stable operation of electronic devices. Particularly in the electrostatic spraying process, the quality of glass powder plays a decisive role, directly influencing the spraying effect and the final performance of the resistor. Therefore, improving the quality and performance of glass powder is of great significance for meeting the ever-evolving demands of electronic devices.

[0003] In existing technologies, the preparation process of glass powder often struggles to precisely control key parameters such as particle size distribution, particle shape, and surface characteristics, leading to unstable performance and significant batch-to-batch variations. This not only affects the uniformity and adhesion of the resistive sheet during electrostatic spraying, making it difficult to achieve ideal spraying results, but also further restricts the improvement of the electrical, mechanical, and stability properties of the resistive sheet, failing to fully meet the stringent quality and performance requirements of resistive sheets driven by the miniaturization and high-performance development of electronic devices.

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

[0005] To address the aforementioned problems, this application provides glass powder for electrostatic spraying of resistor sheets, its preparation method, and its application.

[0006] In a first aspect, this application provides glass powder for electrostatic spraying of resistor sheets, employing the following technical solution:

[0007] A glass powder for electrostatic spraying of resistor sheets comprises the following raw materials in parts by weight:

[0008] The following raw materials are used: 40-60 parts silicon oxide, 10-20 parts boron oxide, 5-15 parts lead oxide, 3-8 parts aluminum oxide, 2-6 parts zinc oxide, 1-4 parts titanium oxide, 0.5-2 parts copper oxide, and 0.1-1 parts cobalt oxide. A binder is added to these raw materials, and the mixture is granulated to obtain glass powder. This powder is then applied to the electrostatic spraying process for glass glaze. The sphericity of the glass powder is ≥90%, and the particle size (D) is... 50 It is 40-50μm.

[0009] By employing the above technical solution, the precise formulation of silicon oxide and boron oxide ensures glass-forming ability and reduces melting temperature; lead oxide significantly improves the wettability, fluidity, and surface tension of the slurry, ensuring a uniform, dense, and strongly adhered coating during electrostatic spraying; aluminum oxide and zinc oxide effectively enhance the coating's hardness, mechanical strength, and thermal stability, improving weather resistance; the addition of appropriate amounts of titanium oxide can fine-tune the dielectric constant and improve compatibility with the substrate electrode; the key addition of trace amounts of copper oxide and cobalt oxide plays a synergistic role, regulating the glass's resistivity and coefficient of thermal expansion, working together with the main lead oxide to ensure that the final sintered coating's electrical properties precisely meet the technical requirements of the resistor sheet. This composite formulation ultimately ensures low-temperature, high-efficiency sintering while significantly improving the coating's uniformity, density, adhesion strength, electrical performance consistency, and long-term reliability, comprehensively optimizing the resistor sheet's production efficiency and product quality.

[0010] Granulating glass powder reduces friction with the inner wall of the spray gun during electrostatic spraying, lowers charge loss, and ensures uniform force distribution in the electric field, preventing agglomeration. Its highly regular spherical structure and precise particle size control ensure that the powder obtains a uniform and sufficient charge distribution in the electrostatic field, ensuring that the powder moves in a laminar flow state in the electric field, avoiding local accumulation caused by turbulence. This significantly improves spraying transmission efficiency and deposition uniformity, reduces spray gun clogging and dust, and results in a more uniform and dense glass glaze layer, thereby improving the overall performance of the resistive sheet.

[0011] Optionally, the adhesive is a 6-10 wt% aqueous solution of polyvinyl alcohol, and the ratio of its addition to the glass powder is 1:16-20.

[0012] Optionally, the surface of the glass powder particles 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 a solution containing a fluorosilicone polymer ethanol solution and cerium oxide sol.

[0013] By adopting the above technical solutions and further coating the surface, the process stability and functional characteristics of electrostatic spraying of glass glaze are significantly improved. The nano-silicon nitride layer, as a high-hardness insulating skeleton, enhances the mechanical strength of the particles and optimizes the interfacial bonding with the glaze matrix. The fluorosilicone polymer, by reducing surface energy, imparts excellent moisture resistance and flowability to the powder to adapt to fluctuations in environmental humidity. Furthermore, it acts as a lubricating layer for high-temperature decomposition, promoting orderly melting and spreading between particles in the early stages of sintering, eliminating bubbles and pinholes. The mesoporous cerium oxide coating plays a dual role—utilizing its high specific surface area to adsorb organic impurities and purify the sintering environment, while simultaneously acting 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 a comprehensive improvement in powder flowability, bulk density, high-temperature wettability, and interfacial electrochemical stability, ultimately resulting in an ultra-thin, dense, defect-free, high-insulation-strength, and anti-aging glaze layer, directly enhancing the long-term reliability of the resistor sheet.

[0014] 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.

[0015] By adopting the above technical solution, the fluorosilicone polymer decomposes to generate gaseous small molecules during high-temperature melting, which promotes the rearrangement of glass particles, reduces the viscosity of the melt, and forms an instantaneous air cushion layer to achieve high-temperature melting densification. At the same time, the directional arrangement of its perfluoroalkyl chains precisely regulates the surface energy of the powder, ensuring uniform charge distribution in electrostatic spraying and low moisture content under fluctuating environmental humidity. Mesoporous cerium oxide adsorbs the organic volatiles released during sintering through the mesoporous confinement trapping mechanism, avoiding insulation degradation. Furthermore, through the oxygen vacancy self-repair mechanism, it releases active oxygen ions during the glaze cooling period, neutralizing electrode migration ions and filling oxygen defect sites in the glass network to achieve electrochemical interface passivation. The synergistic ratio of the two produces a magnification effect. The decomposed gas of the fluorosilicone polymer opens the cerium oxide channels to improve adsorption efficiency, while the mesoporous cerium oxide adsorbs impurities and reduces the decomposition activation energy of the fluorosilicone polymer. Ultimately, multiple breakthroughs are achieved at ultra-low addition levels, including extremely low glaze porosity, small surface roughness, low dielectric loss, and a significant reduction in dendrite density.

[0016] Optionally, the fluorosilicone polymer is heptadecafluorodecyltriethoxysilane.

[0017] By adopting the above technical solutions, the perfluoroalkyl chains form a dense arrangement, which can greatly reduce the surface energy of the powder, increase the static water contact angle, reduce the moisture content of the powder, eliminate the defects in electrostatic spraying, and significantly improve the yield. The ethoxyl group is hydrolyzed and condensed to form a firm bond with the powder surface. It is precisely thermally decomposed in the sintering window to release gaseous substances, reduce the viscosity of the molten glass, eliminate micro-porosity, optimize the roughness of the glaze and improve the gloss. The complete gasification and dissipation of the decomposition products avoids the risk of organic carbon residue. The fluorine-containing gas forms an F⁻ ion barrier to inhibit the migration of electrode metal ions, stabilize the insulation strength and extend the high-voltage aging life, thus comprehensively improving the performance and quality of the product.

[0018] Optionally, the cerium oxide has a mesopore size of 5-15 nm and a specific surface area ≥200 m². 2 / g.

[0019] By adopting the above technical solution, the mesoporous channels with specific pore sizes can act like precise sieves, efficiently capturing organic volatiles released during sintering that match the pore size through capillary coagulation. The ultra-high specific surface area provides a massive number of adsorption sites, greatly enhancing 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 a high concentration of surface oxygen vacancies, which release active oxygen during sintering. This oxygen can neutralize electrode migration ions, inhibit metal dendrite growth, fill oxygen defect sites in the glaze, reduce dielectric loss, and ensure rapid diffusion of oxygen ions to achieve local defect repair. The nano-confinement effect of the mesoporous framework lowers the cerium oxide phase transition threshold, causing it to undergo dynamic valence state transformation during the glaze melting stage. By releasing or absorbing lattice oxygen, it buffers thermal stress, adaptively matches the thermal expansion difference at the glaze-electrode interface, effectively inhibits the initiation of microcracks, and comprehensively improves the performance and reliability of the material.

[0020] Secondly, this application provides a method for preparing glass powder particles for electrostatic spraying of resistor sheets, using the following technical solution:

[0021] A method for preparing glass powder for electrostatic spraying of resistor sheets includes the following steps:

[0022] (1) Mix the raw materials according to the mixing ratio, melt them at 1450-1550℃ and keep them at the temperature for 2-3 hours. Take them out, quench them in water, crush them, and then ball mill them to obtain the basic glass powder.

[0023] (2) The basic glass powder is granulated to obtain glass powder particles. A mixture of silane and ammonia gas 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 deposition. After the deposition is completed, the functional layer coating solution is atomized and uniformly coated on the surface of the powder. The powder is then sieved to obtain glass powder particles coated with the functional layer.

[0024] By adopting the above technical solution, through the precise synergy of high-temperature melting and water quenching with plasma activation and in-situ composite coating, the glass network is first completely depolymerized by melting at 1450-1550℃, followed by water quenching to obtain high-energy metastable glass, which inhibits crystallization and avoids glaze cracking, thus optimizing the activity of the basic powder. Then, radio frequency plasma is 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 bonding energy, and particle compressive strength. Finally, atomizing fluorosilane ethanol solution and cerium oxide sol, the fluorosilane self-assembles into a continuous hydrophobic film, and the mesoporous cerium oxide sol is electrostatically adsorbed and anchored on the outside with unobstructed pores. Simultaneous sieving achieves particle size control, further improving the anti-aging performance and surface activity of the glass powder. The final glass powder particles coated with functional layers are obtained after sieving.

[0025] Optionally, in step (2), the volume ratio of NH3 to SiH4 is controlled to be 1:1.5-2, and the deposition time is 10-15 min; the pressure applied during atomization in step (2) is 0.7-0.9 MPa.

[0026] By employing the above technical solution, silane and ammonia react fully in a plasma environment to generate a chemically stable and dense silicon nitride layer. This effectively avoids uneven silicon nitride composition or structural defects caused by imbalances in the ratio, thereby ensuring that the silicon nitride layer provides excellent protection for the base glass powder and enhances its resistance to corrosion and oxidation. Simultaneously, setting the deposition time to 10-15 minutes ensures that the silicon nitride layer thickness reaches the ideal range of 30-50 nm while avoiding resource waste and interlayer stress problems caused by over-deposition. Furthermore, controlling the atomization pressure at 0.7-0.9 MPa allows the ethanol solution containing fluorinated silicon polymers and cerium oxide sol to be fully atomized into uniform and fine droplets, uniformly coating the powder surface with just the right force to form a complete, dense, and uniform functional layer. This comprehensively improves the overall performance of the glass powder, enabling it to exhibit higher stability and reliability in subsequent applications.

[0027] Thirdly, the application of glass powder for electrostatic spraying of resistor sheets in the electrostatic spraying process of resistor sheets, using the glass powder for electrostatic spraying of resistor sheets prepared in this application, specifically includes the following steps:

[0028] (a) Apply 55-65kV high voltage to electrostatically spray glass powder onto the side of the resistor sheet preheated to 150-160℃ to form a 90-110μm powder deposition layer.

[0029] (b) The powder deposition layer is scanned and sintered at a speed of 0.5-2 m / s using a pulsed infrared laser with a wavelength of 1064 nm and a power density of 30-40 W / cm²; the local temperature gradient is controlled to be ≤200℃ / mm during laser sintering.

[0030] In summary, this application has the following beneficial effects:

[0031] 1. This application presents a composite formulation achieved by precisely blending basic components such as silicon oxide, boron oxide, and lead oxide, and adding auxiliary components such as aluminum oxide, zinc oxide, titanium oxide, copper oxide, and cobalt oxide. This formulation not only ensures 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 flowability 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, improving compatibility with the substrate electrode; and copper oxide and cobalt oxide synergistically regulate the resistive properties and coefficient of thermal expansion of the glass. The synergistic effect of these components enables the final sintered coating to precisely meet the technical requirements of the resistor sheet, comprehensively optimizing the production efficiency and product quality of the resistor sheet.

[0032] 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 the interfacial bonding force; the fluorosilicone polymer imparts moisture resistance and flowability to the powder, promoting particle melting and spreading in the early stage of sintering and eliminating bubbles and pinholes; the mesoporous cerium oxide adsorbs organic impurities, passivates oxygen defects at the electrode interface, and inhibits the electrochemical aging of the coating. The composite coating structure synergistically improves the powder's flowability, bulk density, high-temperature wettability, and interfacial electrochemical stability, resulting in an ultra-thin, dense, defect-free, high-insulation-strength, and anti-aging glaze layer, directly improving the long-term reliability of the resistor sheet.

[0033] 3. The method of this application employs electrostatic spraying and pulsed infrared laser sintering processes with specific parameters. A high voltage of 55-65kV is applied to spray glass powder particles onto the side of the preheated resistor sheet, forming a powder deposition layer of suitable thickness. Then, scanning sintering is performed with specific wavelength, power density, and speed, while controlling the local temperature gradient. This precise and 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 sheet. Attached Figure Description

[0034] Figure 1 These are typical characteristics of the particle morphology of granulated glass powder under a microscope in Example 4;

[0035] Figure 2 These are typical characteristics of the particle morphology of the glass powder prepared in Comparative Example 1 under a microscope. Detailed Implementation

[0036] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources.

[0037] The fluorosilicone polymer was purchased from Guangdong Zhongke Hongtai New Materials Co., Ltd., model: B-334; the resistor was a D42 zinc oxide resistor purchased from Shanghai Beiyuan Industry & Trade Co., Ltd.

[0038] Preparation examples of raw materials and / or intermediates

[0039] Preparation Example 1

[0040] A functional layer encapsulation solution is prepared by the following steps:

[0041] To prepare an ethanol solution of fluorosilicone polymer, heptadecafluorodecyltriethoxysilane (fluorosilicone polymer) was dissolved in anhydrous ethanol at a mass fraction of 10%, and stirred in a water bath at 50°C for 2 hours to ensure complete dissolution, thus obtaining an ethanol solution of fluorosilicone polymer.

[0042] To prepare cerium oxide sol, cerium nitrate hexahydrate was dissolved in deionized water, and an appropriate amount of ammonia was added to adjust the pH value to 9-10. The mixture was stirred at 60℃ for 4 hours to carry out hydrolysis and condensation reactions, thereby obtaining cerium oxide sol.

[0043] Take 1 kg of ethanol solution containing fluorinated silicon polymer and mix it with 9 kg of cerium oxide sol. Then, ultrasonically treat the mixture in an ultrasonic cleaner for 30 minutes to ensure that the two solutions are fully mixed and homogeneous, thus obtaining the functional layer coating solution.

[0044] Preparation Example 2

[0045] A functional layer encapsulation solution differs from Preparation Example 1 in that 1 kg of ethanol solution containing fluorinated silicon polymer is mixed with 8 kg of cerium oxide sol in this preparation example, and the remaining steps are the same as in Preparation Example 1.

[0046] Preparation Example 3

[0047] A functional layer encapsulation solution differs from Preparation Example 1 in that 1 kg of ethanol solution of fluorinated silicon polymer is mixed with 10 kg of cerium oxide sol in this preparation example, and the remaining steps are the same as in Preparation Example 1.

[0048] Example

[0049] Example 1

[0050] A type of glass powder for electrostatic spraying of resistor sheets is prepared by the following steps:

[0051] (1) Weigh 50kg silicon oxide, 15kg boron oxide, 5kg lead oxide, 5kg aluminum oxide, 4kg zinc oxide, 2kg titanium oxide, 1kg copper oxide and 0.5kg cobalt oxide, mix them evenly and transfer them to a high-temperature furnace. After melting at 1500℃, keep warm for 2 hours and quench with water. After the glass particles are initially crushed, put them into a ball mill for fine grinding. Use aluminum oxide balls as the ball milling medium and ball mill for 4 hours to obtain basic glass powder.

[0052] (2) After drying 54 kg of basic glass powder at 100℃ for 5 h, it was put into a granulator for granulation. During granulation, 3 kg of 8 wt% polyvinyl alcohol aqueous solution was sprayed in, and the rotation speed of the granulator was controlled at 300 r / min. The granulation time was 15 min, and the sphericity was ≥90% and the powder D was obtained. 50 It consists of glass powder particles of 40-50 μm.

[0053] Example 2

[0054] A type of glass powder for electrostatic spraying of resistor sheets is prepared by the following steps:

[0055] (1) Weigh 40kg silicon oxide, 20kg boron oxide, 15kg lead oxide, 3kg aluminum oxide, 6kg zinc oxide, 4kg titanium oxide, 0.5kg copper oxide and 1kg cobalt oxide, mix them evenly and transfer them to a high-temperature furnace. After melting at 1450℃, keep warm for 3 hours and quench with water. After the water-quenched glass particles are initially crushed, put them into a ball mill for fine grinding. Use aluminum oxide balls as the ball milling medium and ball mill for 4 hours to obtain basic glass powder.

[0056] (2) After drying 48 kg of basic glass powder at 100℃ for 5 h, it was put into a granulator for granulation. During granulation, 3 kg of 8 wt% polyvinyl alcohol aqueous solution was sprayed in, and the rotation speed of the granulator was controlled at 300 r / min. The granulation time was 15 min, and the sphericity was ≥90% and the powder D was obtained. 50 It consists of glass powder particles of 40-50 μm.

[0057] Example 3

[0058] A type of glass powder for electrostatic spraying of resistor sheets is prepared by the following steps:

[0059] (1) Weigh 60kg silicon oxide, 10kg boron oxide, 10kg lead oxide, 8kg aluminum oxide, 2kg zinc oxide, 1kg titanium oxide, 2kg copper oxide and 0.1kg cobalt oxide, mix them evenly and transfer them to a high-temperature furnace. After melting at 1550℃, keep it at the temperature for 2 hours and then quench it with water. After the glass particles are initially crushed, put them into a ball mill for fine grinding. Use aluminum oxide balls as the ball milling medium and ball mill for 4 hours to obtain basic glass powder.

[0060] (2) After drying 60 kg of basic glass powder at 100℃ for 5 h, it is put into a granulator for granulation. During granulation, 3 kg of 8 wt% polyvinyl alcohol aqueous solution is sprayed in, and the rotation speed of the granulator is controlled at 300 r / min. The granulation time is 15 min, and the sphericity is ≥90% and the powder D is ≥90%. 50 It consists of glass powder particles of 40-50 μm.

[0061] Example 4

[0062] A glass powder for electrostatic spraying of resistor sheets, differing from Example 1 in that the glass powder in this example is coated with a silicon nitride layer and a functional layer, specifically including the following steps:

[0063] 50 kg of the glass powder prepared in Example 1 was placed in a plasma deposition apparatus, and the vacuum was evacuated to 0.01 MPa. A mixture of silane and ammonia gas was introduced into the apparatus, with the NH3 / SiH4 volume ratio controlled at 1:1.8. Simultaneously, the plasma generator was turned on at a frequency of 13.56 MHz and a power of 120 W, and the deposition time was 12 min. A silicon nitride layer of 30-50 nm thickness was formed on the surface of the base glass powder. After deposition, the powder was removed, dried, and set aside. The silicon nitride-coated glass powder was placed in a fluidized bed spray dryer, and nitrogen gas was introduced to fluidize the powder. 3.5 kg of the functional layer coating solution prepared in Example 1 was sprayed into the fluidized bed in droplet form at a pressure of 0.8 MPa, with a spray rate of 10 mL / min. The fluidized bed temperature was controlled at 40 °C. After spraying was stopped, fluidization continued for 10 min to solidify the coating layer. The powder was then sieved through a 325-mesh sieve to obtain glass powder coated with both the silicon nitride layer and the functional layer. The particle morphology under a microscope is shown in the figure. Figure 1 .

[0064] Example 5

[0065] A glass powder for electrostatic spraying of resistor sheets, differing from Example 1 in that the glass powder in this example is coated with a silicon nitride layer and a functional layer, specifically including the following steps:

[0066] 50 kg of the glass powder prepared in Example 1 was placed in a plasma deposition apparatus, and the vacuum was evacuated to 0.01 MPa. A mixture of silane and ammonia gas 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 was turned on at a frequency of 13.56 MHz and a power of 100 W. The deposition time was 15 min, and a silicon nitride layer with a thickness of 30-50 nm was formed on the surface of the base glass powder. After deposition, the powder was removed, dried, and set aside for later use. The silicon nitride-coated glass powder was placed in a fluidized bed spray dryer, and nitrogen gas was introduced to fluidize the powder. 2.5 kg of the functional layer coating solution prepared in Example 1 was sprayed into the fluidized bed in the form of droplets at a pressure of 0.7 MPa and a spray rate of 10 mL / min. The fluidized bed temperature was controlled to be 40 °C. After spraying was stopped, fluidization was continued for 10 min to solidify the coating layer. The powder was then sieved through a 325-mesh sieve to obtain glass powder coated with a silicon nitride layer and a functional layer.

[0067] Example 6

[0068] A glass powder for electrostatic spraying of resistor sheets, differing from Example 1 in that the glass powder in this example is coated with a silicon nitride layer and a functional layer, specifically including the following steps:

[0069] 50 kg of the glass powder prepared in Example 1 was placed in a plasma deposition apparatus, and the vacuum was evacuated to 0.01 MPa. A mixture of silane and ammonia gas 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 was turned on at a frequency of 13.56 MHz and a power of 150 W. The deposition time was 10 min, and a silicon nitride layer with a thickness of 30-50 nm was formed on the surface of the base glass powder. After deposition, the powder was removed, dried, and set aside. The silicon nitride-coated glass powder was placed in a fluidized bed spray dryer, and nitrogen gas was introduced to fluidize the powder. 4.5 kg of the functional layer coating solution prepared in Example 1 was sprayed into the fluidized bed in the form of droplets at a pressure of 0.9 MPa and a spray rate of 10 mL / min. The fluidized bed temperature was controlled to be 40 °C. After spraying was stopped, fluidization was continued for 10 min to solidify the coating layer. The powder was then sieved through a 325-mesh sieve to obtain glass powder coated with a silicon nitride layer and a functional layer.

[0070] Application Example 1

[0071] The application of glass powder particles in electrostatic spraying of resistor sheets specifically includes the following steps:

[0072] (a) Apply a 60kV high voltage to electrostatically spray the glass powder prepared in Example 1 onto the side of a resistor preheated to 155°C to form a 100μm powder deposition layer;

[0073] (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; the local temperature gradient was controlled to be ≤200℃ / mm during laser sintering.

[0074] Application Example 2

[0075] The application of glass powder particles in electrostatic spraying of resistor sheets specifically includes the following steps:

[0076] (a) Apply a 55kV high voltage to electrostatically spray the glass powder prepared in Example 2 onto the side of the resistor sheet preheated to 160°C to form a 90μm powder deposition layer;

[0077] (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; the local temperature gradient was controlled to be ≤200℃ / mm during laser sintering.

[0078] Application Example 3

[0079] The application of glass powder particles in electrostatic spraying of resistor sheets specifically includes the following steps:

[0080] (a) Apply a 65kV high voltage to electrostatically spray the glass powder prepared in Example 3 onto the side of the resistor sheet preheated to 160°C to form a 110μm powder deposition layer;

[0081] (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; the local temperature gradient was controlled to be ≤200℃ / mm during laser sintering.

[0082] Application Example 4-6

[0083] An application of glass powder for electrostatic spraying of a resistor sheet differs from Application Example 1 in that it uses glass powder prepared in Examples 4-6.

[0084] Comparative Example

[0085] Comparative Example 1

[0086] A glass powder for electrostatic spraying of resistor sheets is prepared by the following steps:

[0087] Weigh out 50 kg of silicon dioxide, 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 thoroughly, and transfer them to a high-temperature furnace. Melt at 1500℃, hold at that temperature for 2 hours, and then quench in water. After initial crushing, place the water-quenched glass particles into a ball mill for fine grinding, using alumina balls as the milling medium. Mill for 4 hours to obtain glass powder. The particle morphology under a microscope is shown in the figure. Figure 2 .

[0088] Comparative Application Example 1

[0089] An application of glass powder for electrostatic spraying of resistive sheets differs from Application Example 1 in that the glass powder prepared in Comparative Example 1 is used in this comparative application example.

[0090] Performance testing

[0091] Insulation strength test: The high current impulse withstand test was carried out according to the method shown in GB / T11032-2020 standard. The maximum withstand value of the impulse capability and the insulation strength were tested by a 4 / 10μs high current.

[0092] Aging test: The rate of change of resistance was tested after 1000 hours at 85℃ / 85%RH according to the method shown in IEC60216-1-2013.

[0093] Table 1 Test Data

[0094]

[0095] Combining Application Examples 1-3 and Comparative Application Example 1 with Table 1, it can be seen that the test data of Application Examples 1-3 are all better than those of Comparative Application Example 1. This indicates that the granulation process can significantly improve the sphericity and particle size uniformity of 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 sheet. The overall performance is better than that of the ungranulated Comparative Application Example 1.

[0096] Combining Application Examples 1-3 and 4-6 with Table 1, it can be seen that the test data of Application Example 4-6 are significantly better than those of Application Example 1-3. This indicates that by introducing a silicon nitride layer and a composite functional layer onto the surface of the granulated powder, a triple protection mechanism of "physical insulation - dynamic lubrication - self-repair" is ultimately achieved through the synergy of various aspects, thus realizing the long-term high reliability of the resistor sheet.

[0097] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A glass powder particle for resistance element electrostatic spraying, characterized by, The glass powder particles are prepared by mixing the following raw materials in the following proportions by weight: Silicon oxide 40-60 parts, boron oxide 10-20 parts, lead oxide 5-15 parts, aluminum oxide 3-8 parts, zinc oxide 2-6 parts, titanium oxide 1-4 parts, copper oxide 0.5-2 parts, cobalt oxide 0.1-1 part, and a binder, and granulating the mixture to obtain the glass powder particles, which are used in the electrostatic spraying process of glass glaze, the sphericity of the glass powder particles being ≥90%, and the D50 of the powder particles being 40-50 μm. The surface of the glass powder particles is coated with a silicon nitride layer and a functional layer from the inside to the outside, the thickness of the silicon nitride layer being 30-50 nm, and the functional layer being obtained by atomizing a functional layer coating solution.

2. A glass powder particle for electrostatic spraying of a resistive sheet 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 to the amount of the glass powder particles is 1:16-20.

3. The glass frit particles for electrostatic spraying of a resistor according to claim 1, wherein: The ratio of the amount of the functional layer coating solution to the amount of the glass powder particles is 5-9:100, and the ratio of the amount of the fluorosilicon polymer ethanol solution to the amount of the cerium oxide sol in the functional layer coating solution is 1:8-10.

4. The glass powder particles for electrostatic spraying of a resistor according to claim 1, wherein: The fluorosilicon polymer is heptadecafluorodecyltriethoxysilane.

5. The glass powder particles for electrostatic spraying of a resistor according to claim 1, wherein: The mesoporous pore size of the cerium oxide is 5-15 nm, and the specific surface area is ≥200 m 2 / g.

6. The method of claim 1, wherein the glass powder particles are prepared by a method comprising: preparing a glass frit; and milling the glass frit to form the glass powder particles. The method comprises the following steps: (1) mixing the raw materials in the mixing ratio, melting at 1450-1550 °C, holding for 2-3 h, taking out, water quenching, crushing, and ball milling to obtain the base glass powder; (2) granulating the base glass powder to obtain the glass powder particles, passing in a mixture of ammonia and silane in a volume ratio of 1:1.5-2 to deposit a 30-50 nm thick silicon nitride layer on the surface of the glass powder particles, atomizing the functional layer coating solution and uniformly coating the surface of the powder particles with the functional layer coating solution after the deposition is completed, and sieving to obtain the glass powder particles coated with the functional layer.

7. A method of preparing glass frit particles for electrostatic spraying of resistors according to claim 6, characterized in that: In step (2), the volume ratio of NH3 to 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.

8. Use of glass powder particles for the electrostatic spray application of a resistor disc in an electrostatic spray application process of a resistor disc, characterized in that: The glass powder particles for electrostatic spraying of a resistance sheet are used, and the method comprises the following steps: (a) applying a high voltage of 55-65 kV to electrostatically spray the glass powder particles to the side of a resistance sheet preheated to 150-160 °C to form a 90-110 μm powder deposition layer; (b) using a pulsed infrared laser with a wavelength of 1064 nm and a power density of 30-40 W / cm² to scan and sinter the powder deposition layer at a speed of 0.5-2 m / S; and controlling the local temperature gradient during laser sintering to be ≤200 °C / mm.

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