Tin-antimony gradient doped insulating semiconductor glaze and low-temperature sintering process thereof

Abstract

The invention relates to the field of semiconductor ceramic preparation, in particular to tin-antimony gradient doped insulating semiconductor glaze and a low-temperature sintering process thereof. The gradient change of the element doping amount per unit volume from the inner layer to the surface layer of the glaze layer is formed through different treatment processes of the tin-antimony solid solution, and compared with traditional uniform doping, the surface electric field distortion rate can be effectively reduced, and the surface pollution flashover voltage can be improved. According to the invention, a composite fluxing agent system is adopted, the sintering temperature is reduced, segmented differential atmosphere sintering is adopted to ensure the structural compactness of the glaze layer, excessive loss of doped elements at high temperature is avoided, and the overall performance of the glaze layer is improved. According to the invention, the surface photocatalytic material is doped and forms a heterojunction structure with the internal doped material after sintering, so that relatively strong surface light cleaning performance is formed, and the probability of pollution flashover is reduced.

Description

Technical Field

[0001] The invention relates to the field of semiconductor ceramic preparation, and in particular to a tin-antimony gradient doped insulating semiconductor glaze and a low-temperature sintering process thereof. Background Art

[0002] High-voltage power transmission and transformation equipment has increasingly stringent requirements on the surface performance of insulators. Traditional semiconductor glazes have significant technical bottlenecks in terms of pollution flashover resistance, mechanical strength and coordination of electrical properties. Existing public patents and literature show that the mainstream technical route focuses on uniform doping system or single function optimization, but none of them has broken through the core problem of gradient structure design and low-temperature sintering coordinated regulation. The specific technical defects are as follows: Existing iron-titanium semiconductor glaze (such as patent CN106630634B) adopts Composite system, through more than 30% The content builds a conductive network. However, the system is prone to form micron-sized iron-titanium oxide grains during high-temperature sintering, which causes the conductive channel to break and increases the electric field distortion rate. Patent CN115521068A attempts to improve conductivity by adding 15% to 20% tin oxide, but its uniform dispersion process results in low surface resistivity and a significant increase in leakage current, making it difficult to meet the needs of UHV scenarios.

[0003] The traditional process relies on high-temperature sintering at 1200-1300℃ (such as patent CN116003162B), which will cause abnormal grain growth, reduce the self-cleaning performance of the glaze, cause component volatilization, and consume too much energy. The energy consumption of a single sintering can reach 8-12 kWh / kg.

[0004] The discontinuous conductive network of the semiconductor glaze layer prepared by the existing technology leads to uneven electric field distribution, the contradiction between high-temperature sintering and component volatilization limits the upper limit of performance, and the gradient structure-interface strength-function synergy lacks systematic control methods. The tin-antimony gradient doping system and segmented sintering process of the present invention are innovative solutions to the above pain points. Summary of the invention

[0005] Based on the above-summarized problems, the present invention provides a tin-antimony gradient doped insulating semiconductor glaze and a low-temperature sintering process thereof, the main feature of which is to achieve a gradient distribution of resistivity inside and outside the glaze layer through gradient doping of tin-antimony solid solution, so that the overall electric field of the glaze layer can be reasonably distributed when in use, and the low-temperature sintering process and the introduction of a surface molybdenum trioxide doped layer are combined to reduce the probability of flashover during use. The specific technical scheme is as follows: The tin-antimony gradient doped insulating semiconductor glaze comprises the following components: 8-11wt% of tin-antimony solid solution, 76-83wt% of base glaze, 1-5wt% of photocatalyst, and 8wt% of flux.

[0006] Furthermore, the tin-antimony solid solution is composed of SnO 2 and Sb 2 O 5 preparation.

[0007] Furthermore, the base glaze comprises zircon white frit, feldspar and Xiangtan clay in a weight ratio of 40:45:15.

[0008] Furthermore, the flux includes spodumene and borax in a weight ratio of 5:3.

[0009] Furthermore, the photocatalytic material is molybdenum trioxide.

[0010] The low temperature sintering process of the tin-antimony gradient doped insulating semiconductor glaze comprises the following steps: S1: preparing the tin-antimony solid solution, using different ball milling processes to prepare the inner slurry and the outer slurry respectively, drying them at 80° C. for 30 minutes after ball milling, and then placing them in a sintering furnace, heating them to 1200° C., keeping them warm for 1 hour, and then naturally cooling them to obtain the inner tin-antimony solid solution and the outer tin-antimony solid solution; S2: preparing the base glaze, and mixing and grinding the base glaze with the inner layer tin-antimony solid solution prepared in S1, the outer layer tin-antimony solid solution prepared in S1, and the photocatalyst, adding a solvent for modulation, and then adding the flux for mixing and stirring, to obtain a bottom glaze layer slurry, a middle glaze layer slurry, and a surface glaze layer slurry; S3: Rotating spraying the glaze slurry of the bottom glaze layer, performing the first rapid drying after spraying, rotating spraying the glaze slurry of the middle glaze layer on the sprayed bottom glaze layer, performing the second rapid drying after spraying, rotating spraying the glaze slurry of the top glaze layer on the sprayed middle glaze layer, performing the third rapid drying after spraying to obtain a multi-layer glaze; S4: The multi-layer glaze sprayed in S3 is sequentially sintered in an oxidizing atmosphere and a reducing atmosphere, and then cooled after sintering to obtain a tin-antimony gradient doped insulating semiconductor glaze.

[0011] Further, the different ball milling processes described in S1 are used to prepare the inner slurry and the outer slurry respectively. The ball milling process parameters of the inner layer slurry include: the rotation speed is set to 200-230 rpm, the ball milling time is set to 4 hours, the ball milling solvent is water, and the mass ratio of φ5 mm, φ3 mm, and φ1 mm in the grinding balls is 1:1:2; The ball milling process parameter settings of the outer layer slurry include: the rotation speed is set to 300-350 rpm, the ball milling time is set to 8 hours, the ball milling solvent is an ethanol-water mixed solvent, and the mass ratio of φ5 mm, φ3 mm, and φ1 mm balls in the grinding balls is 1:1:3.

[0012] Furthermore, the solvent is added in step S2 to adjust the viscosity to 400-600 mPa·s; The mixing and stirring described in S2 was set to a stirring speed of 500 rpm for 40 minutes.

[0013] Further, the thickness of the sprayed bottom glaze layer slurry in S3 is 200-300 μm, the thickness of the sprayed middle glaze layer slurry is 400-600 μm, and the thickness of the sprayed surface glaze layer slurry is 30-50 μm; In the rotary spraying of the glaze slurry in the glaze layer of S3, when spraying, add 10% of diluent for every 100 μm of spraying and then continue spraying; In the first rapid drying, the second rapid drying and the third rapid drying described in S3, the drying temperature is set at 80-100° C., and the drying time is 5 minutes, 8 minutes and 2 minutes respectively.

[0014] Further, the oxidizing atmosphere sintering described in S4 specifically includes raising the sintering starting temperature to 500°C at a rate of 5°C / min and keeping the temperature for 30 minutes, then raising the temperature to 800°C at a rate of 3°C / min and keeping the temperature constant for 2 hours, and the sintering atmosphere is a mixed gas of air and nitrogen, and the oxygen partial pressure is controlled at 20-30%; The reducing atmosphere sintering described in S4 specifically includes raising the sintering starting temperature to 1100°C at a rate of 2°C / min and maintaining the temperature for 1 hour, then raising the temperature to 1150°C and maintaining the temperature for 1 hour, and the sintering atmosphere adopts a nitrogen-hydrogen mixed gas, and the proportion of hydrogen is controlled at 3-5%; The post-sintering cooling described in S4 specifically includes slow cooling to 800° C. at a rate of 1° C. / min, and then naturally cooling to room temperature.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention forms a gradient change in the element doping amount per unit volume from the inner layer to the surface layer of the glaze layer through different treatment processes for the tin-antimony solid solution. Compared with traditional uniform doping, the present invention can effectively reduce the surface electric field distortion rate and improve the surface flashover voltage.

[0016] (2) The present invention adopts a composite flux system to reduce the sintering temperature, and adopts segmented differentiated atmosphere sintering to ensure the density of the glaze layer structure, avoid the excessive loss of doping elements at high temperature, and improve the overall performance of the glaze layer.

[0017] (3) The present invention forms a heterojunction structure with the internal doping material by doping the surface photocatalyst after sintering, thereby forming a stronger surface light cleaning performance and reducing the probability of dirty flash. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1This is a flow chart of the low-temperature sintering process of the tin-antimony gradient doped insulating semiconductor glaze of the present invention; Figure 2 The volume percentage and cumulative volume percentage distribution diagram of the particle size of the inner layer tin-antimony solid solution of the present invention; Figure 3 The volume percentage and cumulative volume percentage distribution diagram of the particle size of the outer layer tin-antimony solid solution of the present invention; Figure 4 This is a graph showing the UV-visible light diffuse reflection test results of the tin-antimony gradient doped insulating semiconductor glaze of the present invention. DETAILED DESCRIPTION

[0019] The following examples further explain and illustrate the technical solution of the present invention. It is particularly pointed out that each specific implementation method is a concretization and explanation of the technical solution and should not be regarded as limiting the scope of protection of the present invention. Ordinary technicians in this field still have the right to modify the technical solutions of these embodiments and replace part or all of the technical features with equivalents, and these modifications or replacements do not change the essence of the corresponding technical solution and do not make the essence of the corresponding technical solution deviate from the scope of the technical solution described in the present invention.

[0020] The present invention provides a tin-antimony gradient doped insulating semiconductor glaze and a low-temperature sintering process thereof, wherein the glaze comprises: 8-11wt% of tin-antimony solid solution, 76-83wt% of base glaze, 1-5wt% of photocatalyst material, and 8wt% of flux; wherein SnO 2 and Sb 2 O 5 The weight ratio is 92:8; the base glaze includes zircon white frit, feldspar and Xiangtan soil in a weight ratio of 40:45:15; the flux includes spodumene ( ) and borax ( ), with a weight ratio of 5:3; the photocatalyst is molybdenum trioxide (MoO 3 ). Figure 1 The figure shows the preparation process of the tin-antimony gradient doped insulating semiconductor glaze. The detailed preparation steps are as follows: 1. Preparation of tin-antimony solid solution: 1.1 Raw material selection Industrial chemically pure SnO 2 and Sb 2 O 5 As raw materials, SnO 2 Purity greater than 99.5%, Sb 2 O 5 The purity is greater than 92%.

[0021] 1.2 Preparation of inner layer solid solution Preparation: Synthesize tin-antimony solid solution by solid phase reaction. Place the raw materials in a zirconia ball mill for mixed ball milling. The material-ball ratio is set to material: ball: water = 1.0:1.7:1.0. The rotation speed is set to 200-230 rpm. A composite large and small grinding ball system is used. The mass ratio of φ5 mm, φ3 mm, and φ1 mm zirconia balls is 1:1:2. The large ball mainly provides impact force to break the particles, and the small ball refines the surface through friction to form a coarse particle skeleton. The ball milling time was set to 4 hours to refine the powder to D50≤5 μm, retaining some micron-sized pores to facilitate the formation of an inner layer high-concentration conductive network during subsequent glazing; Sodium dodecylbenzene sulfonate (0.5-1 wt%) was added as a surfactant during ball milling to reduce powder agglomeration and ensure uniform distribution.

[0022] After ball milling, it was dried at 80°C for 30 minutes, placed in a sintering furnace, heated to 1200°C, kept at this temperature for 1 hour, and then cooled naturally.

[0023] 1.3 Preparation of outer layer solid solution The prepared raw materials were placed in a zirconia ball mill for mixed ball milling. The material-ball ratio was set to material: ball: solvent = 1.0:1.7:1.0, the speed was set to 300-350 rpm, and a composite ball system was used. The mass ratio of φ5 mm, φ3 mm, and φ1 mm zirconia balls was 1:1:3. The ball milling time was increased to 8 hours, and high shear force was used to further refine the product to make D50 ≤ 2 μm. The ball milling solvent was changed to an ethanol-water mixed solvent with a volume ratio of 3:1 as the dispersion medium to reduce the slurry viscosity and promote nanoscale Uniform dispersion of particles.

[0024] During ball milling, nitrogen is introduced into the ball mill to protect the metal oxides from oxidation during long-term ball milling. stable doping state.

[0025] After ball milling, it was dried at 80°C for 30 minutes, placed in a sintering furnace, heated to 1200°C, kept at this temperature for 1 hour, and then cooled naturally.

[0026] In the above steps, the ball milling process converts mechanical energy into chemical energy through the collision of grinding balls, causing The inner solid solution can form subgrain boundaries through dislocation slip, while the outer solid solution can form through grain boundary diffusion. exist Solid solution doping in the lattice forms p-type semiconductor characteristics; the inner solid solution has a small specific surface area and a high Sn / Sb doping concentration per unit volume, forming a low-resistivity conductive channel; the outer solid solution has a high specific surface area and increased surface active sites, and can form a heterojunction with the subsequent doping of photocatalysts to achieve a resistivity gradient jump; in addition, the outer solid solution nanoparticles are regulated by the surface Zeta potential, so that they are preferentially adsorbed in the coarse particle pores of the inner solid solution during glazing, forming a dense gradient interface, which inhibits the mutual diffusion of elements during sintering.

[0027] 2. Selection and proportion of base glaze and preparation of multi-layer glaze 2.1 Selection and ratio of base glaze The base glaze material needs to provide a stable crystal structure and skeleton function at high temperature, and also needs to provide certain rheological properties and flux function. In combination with the composition of the doped phase of the present invention, zircon white frit, feldspar and Xiangtan soil are selected as the raw materials of the base glaze, and the ratio is set to be 40:45:15 by weight. The chemical composition of zircon white frit, feldspar and Xiangtan soil is shown in Table 1: Table 1 Chemical composition of zirconium white frit, feldspar and Xiangtan soil (wt%)

[0028] The "others" in Table 1 represent the sum of substances with lower content other than the main components, such as trace metal elements. The "loss on ignition" in Table 1 represents the mass percentage lost by the raw materials during high-temperature ignition. The calculation method is: the raw materials are ignited to constant weight at 1000℃, and the reduced mass is the loss on ignition. The ratio of the loss on ignition to the total mass of the raw materials is the "loss on ignition" in Table 1. During the ignition process, the substances volatilized and removed include carbon dioxide, combined water, and a small amount of sulfur, fluorine, chlorine and organic matter. The "loss on ignition" values ​​in Table 1 are derived from the experience records and calculations accumulated from long-term sintering work.

[0029] Based on the above ratio and composition, it can be seen that zirconium white frit acts as a glaze skeleton, providing a stable crystal structure at high temperature. Participate in the formation of the conductive network of tin-antimony solid solution; feldspar is the main flux, which reduces the melting temperature of the glaze, promotes the formation of liquid phase to wrap the conductive phase, and adjusts the viscosity of the glaze to avoid bubble residue; Xiangtan soil provides To enhance the mechanical strength of the glaze layer, improve the rheological properties of the glaze slurry, and reduce drying shrinkage; in addition, the ratio of zircon white frit to feldspar is close to 1:1, which can balance the high temperature stability and melting characteristics. Xiangtan soil is controlled within 20% to avoid Excessive amount will increase the brittleness of the glaze layer.

[0030] 2.2 Preparation of multilayer glaze In order to achieve the improvement of comprehensive performance, layered gradient glazing will be carried out in the future. The glaze layer includes a bottom glaze layer doped with inner solid solution, a middle glaze layer doped with outer solid solution and a surface glaze layer doped with photocatalytic molybdenum trioxide. The preparation ratio of the bottom glaze layer, the middle glaze layer and the surface glaze layer changes according to the total ratio set at the beginning of the raw materials.

[0031] The glaze was prepared by mixing and grinding the doping materials and base glaze of each glaze layer, adding a solvent to prepare a glaze slurry with a viscosity of 400-600 mPa·s (calibrated by a Brookfield viscometer), adding a corresponding proportion of flux and 0.1wt% sodium carboxymethyl cellulose (CMC), and then mixing and stirring. The stirring rate was set to 500 rpm and the stirring time was set to 40 minutes.

[0032] 3. Rotary spraying layered glazing 3.1 Equipment configuration and parameter setting Rotary spraying system: the speed of the spray gun is controlled at 800-1200 rpm, and the spraying distance is set to 20-30 cm to ensure the atomization effect of the glaze slurry and control the atomized particle size to be ≤50 μm; the glaze slurry storage tank is kept at a constant temperature of 25±2℃, and the humidity of the spraying environment is ≥60% to prevent uneven drying of the glaze layer; the spraying thickness of different glaze layers is set as: 200-300 μm for the bottom glaze layer, 400-600 μm for the middle glaze layer, and 30-50 μm for the surface glaze layer.

[0033] 3.2 Base glaze layer glaze spraying The spraying path adopts spiral progressive spraying, and one cycle is counted as coating the entire surface of the embryo. The coating thickness of each cycle is controlled at 20-30 μm. After spraying, rapid drying is carried out immediately, and the drying temperature is set at 80-100°C and the drying time is 5 minutes. Rapid drying can eliminate microcracks in the glaze layer and reduce porosity.

[0034] 3.3 Middle glaze layer glaze spraying The path setting and periodic thickness control during the spraying of the middle glaze layer are the same as those during the spraying of the above-mentioned bottom glaze layer. The difference is that a gradient dilution process is adopted during the spraying of the middle glaze layer. The glaze is gradient diluted and sprayed through a mixing device. 10% of the diluent is added after every 100 μm of spraying. The diluent is deionized water and ethylene glycol in a volume ratio of 1:1. While maintaining the performance of the semiconductor uniform electric field and microchannels, the surface resistance is relatively high, and the surface current during use is controlled within an appropriate range; the spraying interval time of different concentration layers is controlled to be ≤3 minutes to improve the interface shear strength. After spraying, rapid drying is carried out immediately, and the drying temperature is set to 80-100°C and the drying time is 8 minutes.

[0035] 3.4 Surface glaze spraying The path setting for spraying the surface glaze layer is the same as that for the first two layers. The coating thickness of each cycle is controlled at 5-10 μm. After spraying, rapid drying is performed immediately. The drying temperature is set at 80-100°C and the drying time is 2 minutes.

[0036] In the above steps, a gradient resistance distribution gradually increasing from the inside to the outside is formed by glazing different glaze layers. The lower internal resistance can provide a low-resistance channel for carriers, ensuring stable current conduction without local overheating, and also making the glaze layer have a negative temperature coefficient effect. When the local electric field is distorted, the temperature in the area rises, resulting in a decrease in resistance, and the current naturally gathers in the high field strength area to form a self-regulating equalizing voltage mechanism; the higher external resistance can prevent the surface current from being too large and causing electrochemical corrosion of the glaze layer. When there are surface stains, the larger surface resistance can form impedance adaptation with the pollutants, which can prevent the wet dirt layer from being directly short-circuited and increase the flashover voltage; this gradient resistance has a synergistic effect, the internal low resistance ensures that the current conducts and generates heat, and the moderate surface resistance limits the current intensity, so that the drying temperature is stable above the dew point without damaging the glaze layer; the internal rapid response to electric field distortion realizes dynamic equalization, and the higher surface resistance suppresses the starting voltage of sliding flashover discharge; the internal continuous conductive network avoids local arc ablation, and the larger surface resistance reduces glaze aging caused by ion migration.

[0037] 4. Segmented sintering 4.1 Oxidizing atmosphere sintering The starting sintering temperature was increased to 500°C at a rate of 5°C / min and kept at that temperature for 30 minutes to remove residual organic matter, and then increased to 800°C at a rate of 3°C / min and kept at that temperature for 2 hours. The oxidizing atmosphere during sintering used a mixture of air and nitrogen, and the oxygen partial pressure was controlled at 20-30%. The oxygen proportion was accurately controlled by a flow meter.

[0038] Oxidizing atmosphere can promote Filling oxygen vacancies in the lattice reduces lattice defects and improves the conductivity inside the glaze; by regulating the oxygen partial pressure, maintaining oxidation reaction to avoid excessive volatilization of Sb.

[0039] 4.2 Reducing atmosphere sintering The sintering atmosphere was switched to a reducing atmosphere, using a nitrogen-hydrogen mixture with the hydrogen ratio controlled at 3-5%. During sintering, the temperature was raised to 1100°C at 2°C / min and kept constant for 1 hour, then raised to 1150°C and kept constant for 1 hour to complete the sintering.

[0040] Inhibition of reducing effect of hydrogen in atmosphere The further oxidation of the flux and the migration of lithium ions to the grain boundaries and At 950℃, a eutectic glass phase is formed ( ), this liquid phase fills the grain boundary pores, further reducing the porosity and lowering the temperature required for sintering.

[0041] 4.3 Cooling After sintering, the steel was slowly cooled to 800°C at a rate of 1°C / min and then naturally cooled to room temperature to avoid cracking caused by thermal stress. Nitrogen protection was maintained during the cooling stage to prevent re-oxidation.

[0042] In the above steps, MoO 3 with the matrix The reaction generates Mo-Si-O glass phase, which can react with The matrix forms chemical bonds, which is beneficial to improve the mechanical strength; when sintered in a reducing atmosphere, The surface oxygen vacancy concentration increases with the MoO 3 The n-type characteristics form a pn heterojunction, which helps to improve the photocurrent density.

[0043] Example 1 Tin-antimony gradient doped insulating semiconductor glaze and its low temperature sintering process are as follows: The glaze composition includes: 10wt% tin-antimony solid solution, 79wt% base glaze, 3wt% photocatalyst, and 8wt% flux; 2 and Sb 2 O 5 The weight ratio of zirconium white frit, feldspar and Xiangtan soil in the base glaze is 92:8; the weight ratio of spodumene flux and borax is 40:45:15; the weight ratio of spodumene flux and borax is 5:3, and the photocatalyst is molybdenum trioxide (MoO 3 ).

[0044] The preparation process includes: S1: Prepare tin-antimony solid solution by solid phase reaction. First, prepare the inner layer solid solution. Ball mill the tin dioxide and antimony pentoxide raw materials. The ball milling time is set to 4 hours. After ball milling, dry at 80°C for 30 minutes, place in a sintering furnace, heat to 1200°C, keep warm for 1 hour and then cool naturally; then prepare the outer layer solid solution. Ball mill the tin dioxide and antimony pentoxide raw materials. The ball milling time is set to 8 hours. Nitrogen protection is introduced during ball milling. After ball milling, dry and sinter under the same conditions as the inner layer solid solution.

[0045] S2: The base glaze is mixed and ground with the inner layer solid solution, the outer layer solid solution and the doped photocatalyst respectively, and a solvent is added to prepare a glaze slurry with a viscosity of 400-600 mPa·s, and then a flux and 0.1wt% sodium carboxymethyl cellulose are added, and then mixed and stirred. The stirring speed is set to 500 rpm and the stirring time is set to 40 minutes to prepare the bottom glaze layer, the middle glaze layer and the surface glaze layer glaze; S3: First, spray a 250 μm base glaze layer, and dry it at 80-100℃ for 5 minutes. Then spray a 500 μm middle glaze layer, and add 10% diluent every 100 μm to form a gradient spray. After spraying, dry it for 8 minutes under the same conditions as the base glaze layer. Finally, spray a 40 μm surface glaze layer, and dry it for 2 minutes under the same conditions as the base glaze layer.

[0046] S4: First, sinter in an air-nitrogen mixed atmosphere, the starting temperature is increased to 500°C at a rate of 5°C / min and kept at this temperature for 30 minutes, then increased to 800°C at a rate of 3°C / min and kept at this temperature for 2 hours; then, sinter in a nitrogen-hydrogen mixed atmosphere, the temperature is increased to 1100°C at a rate of 2°C / min and kept at this temperature for 1 hour, then increased to 1150°C and kept at this temperature for 1 hour to complete the sintering; after the sintering is completed, it is slowly cooled to 800°C at a rate of 1°C / min, and then naturally cooled to room temperature to obtain a tin-antimony gradient doped insulating semiconductor glaze.

[0047] Example 2 The glaze composition and preparation process of Example 1 are different in that: The glaze composition includes: tin-antimony solid solution 8wt%, base glaze 83wt%, photocatalyst 1wt%, flux 8wt%, and other compositions remain unchanged.

[0048] In step S3 of the preparation process, a base glaze layer of 200 μm is sprayed, and a middle glaze layer of 400 μm and 30 μm is sprayed, and the other steps are the same.

[0049] Example 3 The glaze composition and preparation process of Example 1 are different in that: The glaze composition includes: tin-antimony solid solution 11wt%, base glaze 76wt%, photocatalyst 5wt%, flux 8wt%, and other compositions remain unchanged.

[0050] In step S3 of the preparation process, a base glaze layer of 300 μm is sprayed, a middle glaze layer of 600 μm is sprayed, and a surface glaze layer of 50 μm is sprayed, and the other steps are the same.

[0051] Example 4 The glaze composition and preparation process of Example 1 are different in that: The glaze composition includes: tin-antimony solid solution 9wt%, base glaze 81wt%, photocatalyst 2wt%, flux 8wt%, and other compositions remain unchanged.

[0052] In step S3 of the preparation process, a base glaze layer of 230 μm is sprayed, a middle glaze layer of 450 μm is sprayed, and a surface glaze layer of 35 μm is sprayed, and the other steps are the same.

[0053] Example 5 The glaze composition and preparation process of Example 1 are different in that: The glaze composition includes: tin-antimony solid solution 10wt%, base glaze 78wt%, photocatalyst 4wt%, flux 8wt%, and other compositions remain unchanged.

[0054] In step S3 of the preparation process, a base glaze layer of 280 μm is sprayed, a middle glaze layer of 550 μm is sprayed, and a surface glaze layer of 45 μm is sprayed, and the other steps are the same.

[0055] Comparative Example 1 The preparation steps of reference Example 1 are different in that only the outer layer solid solution is prepared in step S1; only the glazes of the middle glaze layer and the surface glaze layer are prepared in step S2; the glaze layer spraying in step S3 does not adopt the gradient spraying method; the other steps are the same.

[0056] Comparative Example 2 Referring to the preparation steps of Example 1, the difference is that the glaze composition does not include flux, and the original proportion of flux is added to the base glaze; the sintering step in S2 under a nitrogen-hydrogen mixed atmosphere is changed to: during sintering, the temperature is increased to 1200°C at 2°C / min and kept constant for 1 hour, and then increased to 1300°C and kept constant for 1 hour to complete the sintering.

[0057] Experimental Example 1 The inner layer solid solution and the outer layer solid solution prepared in step S1 of Example 1 were sampled respectively, and the particle size distribution of the solid solutions prepared under two different ball milling conditions was tested using a laser particle size analyzer, with specific reference to the national standard GB / T19077-2024 "Particle Size Analysis by Laser Diffraction Method"; As attached Figure 2 and attached Figure 3 , respectively showing the volume percentage and cumulative volume percentage distribution of the inner solid solution and outer solid solution particle sizes. Through the analysis of the results, it can be concluded that the inner solid solution D50≤5 μm and the outer solid solution D50≤2 μm.

[0058] Experimental Example 2 According to Example 1, a separate sample of the tin-antimony gradient-doped insulating semiconductor glaze layer was prepared for optical performance tests, including UV-visible diffuse reflection and photocatalytic self-cleaning tests. The UV-visible diffuse reflection test used a UV-visible diffuse reflection spectrophotometer to test the diffuse reflection spectrum of the sample; the photocatalytic self-cleaning test referred to the national standard GB / T 23762-2009 "Photocatalytic Self-cleaning Material Performance Test Method", and the diatomaceous earth degradation rate was tested under ultraviolet light (365 nm, 1000 W / m²) to simulate the pollutant decomposition ability of the glaze layer under wet pollution.

[0059] UV-Visible diffuse reflection test results are as attached Figure 4As shown in the figure, it can be seen that in addition to the ultraviolet band, molybdenum trioxide can form a photocatalytic substance after being doped in the surface glaze. It has rich electronic energy levels and has a certain absorption of visible light, which promotes the photocatalytic degradation reaction of the surface.

[0060] The photocatalytic self-cleaning test results show that within 8 hours, the diatomaceous earth degradation rate of the sample under ultraviolet light is ≥85%, which meets the self-cleaning requirements of the surface glaze under pollution conditions.

[0061] Experimental Example 3 According to the preparation methods of Examples 1-5 and Comparative Examples 1-2, tin-antimony gradient doped insulating semiconductor glaze layers were prepared on the same embryonic body, and then the volume resistivity of the homogeneous glaze layer of different embodiments or comparative examples, the surface flashover voltage of the overall glaze layer and the mechanical properties of the overall glaze layer were tested respectively.

[0062] The formula composition of the embryo body is shown in Table 2. The volume resistivity is measured by direct current (DC) method with reference to the national standard GB / T 31838.2-2019. When measuring, Examples 1 to 5 respectively measure the individual volume resistivity of the bottom glaze layer, the middle glaze layer and the surface glaze layer after sintering under the same conditions of S4; Comparative Example 1 respectively measures the individual volume resistivity of the middle glaze layer and the surface glaze layer (without the bottom glaze layer) after sintering under the same conditions of S4; Comparative Example 2 respectively tests the individual volume resistivity of the bottom glaze layer, the middle glaze layer and the surface glaze layer after sintering under different sintering conditions; data collection is 50 times of data collection for each individual glaze layer, and the average data magnitude of its resistivity is obtained after statistics for recording and comparison; The surface flashover voltage resistance is tested by simulating salt spray environment (5% NaCl) in reference to the standard IEC 60507:2013 "Artificial Pollution Test"; the mechanical properties are tested by three-point bending test in reference to the national standard GB6569-2006 "Fine Engineering Ceramics Bending Strength Test Method". The test comparison results are shown in Table 3.

[0063] Table 2 Chemical composition of embryo formula (wt%)

[0064] The meaning of "ignition loss" in Table 2 is the same as that in Table 1. The values ​​of "ignition loss" in Table 2 are derived from the experience records and calculations accumulated from long-term sintering work.

[0065] Table 3 Comparison of experimental results of Experimental Example 3 of Examples 1-5 and Comparative Examples 1-2

[0066] From the above comparison results, it can be seen that comparative example 1 does not use a gradient layered glaze system, resulting in a small difference in resistivity between the inside and outside of the glaze layer, and the multiple functions achieved by the gradient resistivity cannot be achieved, resulting in a decrease in the flashover voltage resistance; comparative example 2 does not use a flux, so the sintering temperature has to be increased during the subsequent sintering, which affects the overall density of the glaze layer, resulting in a decrease in the overall performance, especially the mechanical properties. In addition, the high sintering temperature will cause MoO 3 Excessive volatilization affects the surface photocatalytic self-cleaning performance.

Claims

1. Tin-antimony gradient doped insulating semiconductor glaze, characterized in that: The invention comprises the following components: 8-11 wt% of tin-antimony solid solution, 76-83 wt% of base glaze, 1-5 wt% of photocatalyst and 8 wt% of flux.

2. The tin-antimony gradient doped insulating semiconductor glaze according to claim 1, characterized in that: The tin-antimony solid solution is prepared from SnO2 and Sb2O5 in a weight ratio of 92:

8.

3. The tin-antimony gradient doped insulating semiconductor glaze according to claim 1, characterized in that: The base glaze comprises zircon white frit, feldspar and Xiangtan soil in a weight ratio of 40:45:

15.

4. The tin-antimony gradient doped insulating semiconductor glaze according to claim 1, characterized in that: The flux includes spodumene and borax in a weight ratio of 5:

3.

5. The tin-antimony gradient doped insulating semiconductor glaze according to claim 1, characterized in that: The photocatalytic material is molybdenum trioxide.

6. The low temperature sintering process of the tin-antimony gradient doped insulating semiconductor glaze according to any one of claims 1 to 5, characterized in that: The steps include: S1: preparing the tin-antimony solid solution, using different ball milling processes to prepare the inner slurry and the outer slurry respectively, drying them at 80° C. for 30 minutes after ball milling, and then placing them in a sintering furnace, heating them to 1200° C., keeping them warm for 1 hour, and then naturally cooling them to obtain the inner tin-antimony solid solution and the outer tin-antimony solid solution; S2: preparing the base glaze, and mixing and grinding the base glaze with the inner layer tin-antimony solid solution prepared in S1, the outer layer tin-antimony solid solution prepared in S1, and the photocatalyst, adding a solvent for modulation, and then adding the flux for mixing and stirring, to obtain a bottom glaze layer slurry, a middle glaze layer slurry, and a surface glaze layer slurry; S3: Rotating spraying the glaze slurry of the bottom glaze layer, performing the first rapid drying after spraying, rotating spraying the glaze slurry of the middle glaze layer on the sprayed bottom glaze layer, performing the second rapid drying after spraying, rotating spraying the glaze slurry of the top glaze layer on the sprayed middle glaze layer, performing the third rapid drying after spraying to obtain a multi-layer glaze; S4: The multi-layer glaze sprayed in S3 is sequentially sintered in an oxidizing atmosphere and a reducing atmosphere, and then cooled after sintering to obtain a tin-antimony gradient doped insulating semiconductor glaze.

7. The low temperature sintering process of the tin-antimony gradient doped insulating semiconductor glaze according to claim 6, characterized in that: The different ball milling processes described in S1 are used to prepare the inner slurry and the outer slurry respectively. The ball milling process parameters of the inner layer slurry include: the rotation speed is set to 200-230 rpm, the ball milling time is set to 4 hours, the ball milling solvent is water, and the mass ratio of φ5 mm, φ3 mm, and φ1 mm in the grinding balls is 1:1:2; The ball milling process parameter settings of the outer layer slurry include: the rotation speed is set to 300-350 rpm, the ball milling time is set to 8 hours, the ball milling solvent is an ethanol-water mixed solvent, and the mass ratio of φ5 mm, φ3 mm, and φ1 mm balls in the grinding balls is 1:1:

3.

8. The low temperature sintering process of the tin-antimony gradient doped insulating semiconductor glaze according to claim 6, characterized in that: The solvent is added as described in S2, and the viscosity of the mixture is adjusted to 400-600 mPa·s; The mixing and stirring described in S2 was set to a stirring speed of 500 rpm for 40 minutes.

9. The low temperature sintering process of the tin-antimony gradient doped insulating semiconductor glaze according to claim 6, characterized in that: The thickness of the sprayed bottom glaze layer slurry in S3 is 200-300 μm, the thickness of the sprayed middle glaze layer slurry is 400-600 μm, and the thickness of the sprayed surface glaze layer slurry is 30-50 μm; In the rotary spraying of the glaze slurry in the glaze layer of S3, 10% of the diluent is added for every 100 μm of spraying and then the spraying is continued; In the first rapid drying, the second rapid drying and the third rapid drying described in S3, the drying temperature is set at 80-100° C., and the drying time is 5 minutes, 8 minutes and 2 minutes respectively.

10. The low temperature sintering process of the Sn-Antimony gradient doped insulating semiconductor glaze according to claim 6, characterized in that: The oxidizing atmosphere sintering described in S4 specifically includes the sintering starting temperature being raised to 500°C at a rate of 5°C / min and kept at that temperature for 30 minutes, and then raised to 800°C at a rate of 3°C / min and kept at that temperature for 2 hours, the sintering atmosphere being a mixed gas of air and nitrogen, and the oxygen partial pressure being controlled at 20-30%; The reducing atmosphere sintering described in S4 specifically includes raising the sintering starting temperature to 1100°C at a rate of 2°C / min and maintaining the temperature for 1 hour, then raising the temperature to 1150°C and maintaining the temperature for 1 hour, and the sintering atmosphere adopts a nitrogen-hydrogen mixed gas, and the proportion of hydrogen is controlled at 3-5%; The post-sintering cooling described in S4 specifically includes slow cooling to 800° C. at a rate of 1° C. / min, and then naturally cooling to room temperature.

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