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

Abstract

The present invention relates to the field of semiconductor ceramic preparation, and specifically relates to a tin-antimony gradient-doped insulating semiconductor glaze and its low-temperature sintering process. By different treatment processes for the tin-antimony solid solution, 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. Compared with traditional uniform doping, the present invention can effectively reduce the surface electric field distortion rate and improve the surface pollution flashover voltage. The present invention adopts a composite flux system to reduce the sintering temperature, and uses segmented differential atmosphere sintering to ensure the denseness of the glaze layer structure, and avoids excessive loss of doping elements at high temperatures, thereby improving the overall performance of the glaze layer. Through the doping of surface photocatalytic materials, a heterojunction structure is formed with the internal doping materials after sintering, forming a strong surface photocleaning performance and reducing the probability of pollution flashover occurrence.

Description

Technical Field

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

[0002] The requirements for the surface performance of insulators in high-voltage power transmission and transformation equipment are becoming increasingly stringent. There are significant technical bottlenecks in the coordination of anti-fouling flashover, mechanical strength, and electrical properties in traditional semiconductor glazes. Existing publicly available patents and literature show that the mainstream technical routes focus on homogeneous doping systems or single-function optimization, but none have broken through the core problem of the coordinated regulation of gradient structure design and low-temperature sintering. The specific technical defects are as follows:

[0003] Existing iron-titanium type semiconductor glaze (such as patent CN106630634B) uses a composite system to construct a conductive network through a content of more than 30% . However, in this system, micron-sized iron-titanium oxide grains are easily formed during high-temperature sintering, resulting in the fracture of the conductive channels and an increase in the electric field distortion rate. Patent CN115521068A attempts to improve conductivity by adding 15% - 20% tin oxide, but its uniform dispersion process results in a relatively low surface resistivity and a significant increase in leakage current, making it difficult to meet the requirements of the extra-high voltage scenario.

[0004] Traditional processes rely on high-temperature sintering at 1200 - 1300 °C (such as patent CN116003162B), which can cause abnormal grain growth, reduce the self-cleaning performance of the glaze surface, cause component volatilization, and have too high energy consumption. The energy consumption per single sintering can reach 8 - 12 kWh / kg.

[0005] In the semiconductor glaze layer prepared by the existing technology, the conductive network is discontinuous, resulting in uneven electric field distribution. The contradiction between high-temperature sintering and component volatilization limits the performance upper limit, and there is a lack of systematic regulation means for the gradient structure - interface strength - function coordination. The tin-antimony gradient-doped system and segmented sintering process of the present invention are innovative solutions proposed for the above pain points. Summary of the Invention

[0006] Based on the problems summarized above, the present invention provides a tin-antimony gradient-doped insulating semiconductor glaze and its low-temperature sintering process. Its main feature is to achieve a gradient distribution of resistivity inside and outside the glaze layer through the gradient doping of a tin-antimony solid solution, so that the overall electric field during the use of the glaze layer can be reasonably distributed. Combining the low-temperature sintering process and the introduction of a surface molybdenum trioxide doped layer reduces the occurrence probability of fouling flashover during use. The specific technical solutions are as follows:

[0007] The tin-antimony gradient-doped insulating semiconductor glaze contains 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.

[0008] Furthermore, the tin-antimony solid solution is prepared from SnO2 and Sb2O5 with a weight ratio of 92:8.

[0009] Furthermore, the base glaze comprises zirconium white frit, feldspar and Xiangtan clay, with a weight ratio of 40:45:15.

[0010] Furthermore, the flux comprises spodumene and borax, with a weight ratio of 5:3.

[0011] Furthermore, the photocatalyst is molybdenum trioxide.

[0012] The low-temperature sintering process of the tin-antimony gradient-doped insulating semiconductor glaze comprises the following steps:

[0013] S1: Prepare the tin-antimony solid solution. Inner-layer slurry and outer-layer slurry are respectively prepared by using different ball-milling processes. After ball-milling is completed, they are dried at 80 °C for 30 minutes respectively, then placed into a sintering furnace, heated to 1200 °C, kept warm for 1 hour and then naturally cooled to obtain the inner-layer tin-antimony solid solution and the outer-layer tin-antimony solid solution;

[0014] S2: Configure the base glaze, and respectively mix and grind 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, add a solvent for modulation, and then add the flux for mixing and stirring to respectively obtain the bottom-glaze layer glaze slurry, the middle-glaze layer glaze slurry and the surface-glaze layer glaze slurry;

[0015] S3: Rotationally spray the bottom-glaze layer glaze slurry. After spraying is completed, perform the first rapid drying. Rotationally spray the middle-glaze layer glaze slurry on the completed bottom-glaze layer. After spraying is completed, perform the second rapid drying. Rotationally spray the surface-glaze layer glaze slurry on the completed middle-glaze layer. After spraying is completed, perform the third rapid drying to obtain a multi-layer glaze;

[0016] S4: Sequentially perform oxidation atmosphere sintering and reduction atmosphere sintering on the multi-layer glaze sprayed in S3, and cool after sintering to obtain the tin-antimony gradient-doped insulating semiconductor glaze.

[0017] Furthermore, the different ball-milling processes in S1 are used to respectively prepare the inner-layer slurry and the outer-layer slurry,

[0018] wherein, the ball-milling process parameters of the inner-layer slurry are set as follows: 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 the balls with φ5 mm, φ3 mm and φ1 mm in the grinding balls is 1:1:2;

[0019] Among them, the ball milling process parameters of the outer layer slurry are set as follows: 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 balls with diameters of φ5 mm, φ3 mm, and φ1 mm in the grinding balls is 1:1:3.

[0020] Further, for the addition of solvent modulation in S2, the modulated viscosity is 400 - 600 mPa·s;

[0021] For the mixing and stirring in S2, the parameters are set to stir at a speed of 500 rpm for 40 minutes.

[0022] Further, the thickness of the primer glaze layer slurry sprayed in S3 is 200 - 300 μm, the thickness of the intermediate glaze layer slurry is 400 - 600 μm, and the thickness of the topcoat glaze layer slurry is 30 - 50 μm;

[0023] For the rotary spraying of the intermediate glaze layer slurry in S3, add 10% diluent every time 100 μm is sprayed and then continue spraying;

[0024] For the first rapid drying, the second rapid drying, and the third rapid drying in S3, the drying temperature is set to 80 - 100°C, and the drying times are 5 minutes, 8 minutes, and 2 minutes in sequence.

[0025] Further, for the sintering in an oxidizing atmosphere in S4, it specifically includes raising the starting sintering temperature to 500°C at a rate of 5°C / min and holding for 30 minutes, then raising it to 800°C at a rate of 3°C / min and keeping it constant for 2 hours. The sintering atmosphere uses a mixed gas of air and nitrogen, and the oxygen partial pressure is controlled at 20 - 30%;

[0026] For the sintering in a reducing atmosphere in S4, it specifically includes raising the starting sintering temperature to 1100°C at a rate of 2°C / min and holding for 1 hour, then raising it to 1150°C and holding for 1 hour. The sintering atmosphere uses a mixed gas of nitrogen - hydrogen, and the hydrogen proportion is controlled at 3 - 5%;

[0027] For the cooling after sintering in S4, it specifically includes slowly cooling to 800°C at a rate of 1°C / min, and then naturally cooling to room temperature.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) By forming 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, the present invention can effectively reduce the surface electric field distortion rate and improve the surface pollution flashover voltage compared with traditional uniform doping.

[0030] (2) The present invention adopts a composite flux system to reduce the sintering temperature, and uses segmented differential atmosphere sintering to ensure the denseness of the glaze layer structure, and avoids excessive loss of doping elements at high temperatures, thereby improving the overall performance of the glaze layer.

[0031] (3) Through the doping of surface photocatalytic materials, the present invention forms a heterojunction structure with the internal doping materials after sintering, forming strong surface photocleaning performance and reducing the probability of pollution flashover. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flowchart of the low-temperature sintering process of the tin-antimony gradient-doped insulating semiconductor glaze of the present invention;

[0033] Figure 2 It is a distribution diagram of the volume percentage and cumulative volume percentage of the particle size of the inner-layer tin-antimony solid solution of the present invention;

[0034] Figure 3 It is a distribution diagram of the volume percentage and cumulative volume percentage of the particle size of the outer-layer tin-antimony solid solution of the present invention;

[0035] Figure 4 It is a UV-visible diffuse reflection test result diagram of the tin-antimony gradient-doped insulating semiconductor glaze of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0036] The following examples further explain and illustrate the technical solutions of the present invention. It is particularly pointed out that each specific implementation manner is a specific implementation and interpretation of the technical solution, and should not be regarded as a limitation on the protection scope of the present invention. Those of ordinary skill in the art still have the right to modify the technical solutions of these examples and perform equivalent replacements on some or all of the technical features, and these modifications or replacements do not change the essence of the corresponding technical solutions and do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions described in the present invention.

[0037] The present invention provides a tin-antimony gradient-doped insulating semiconductor glaze and its low-temperature sintering process. The glaze composition includes: 8-11 wt% of tin-antimony solid solution, 76-83 wt% of base glaze, 1-5 wt% of photocatalytic material, and 8 wt% of flux; wherein, the weight ratio of SnO2 and Sb2O5 in the tin-antimony solid solution is 92:8; the composition of the base glaze includes zircon white frit, feldspar and Xiangtan clay, with a weight ratio of 40:45:15; the flux includes spodumene ( ) and borax ( ), with a weight ratio of 5:3; the photocatalytic material is molybdenum trioxide (MoO3). As shown in the attached Figure 1 figure, it is the preparation process of the tin-antimony gradient-doped insulating semiconductor glaze, and its detailed preparation steps are as follows:

[0038] 1. Preparation of tin-antimony solid solution:

[0039] 1.1 Raw material selection

[0040] Industrial chemically pure SnO2 and Sb2O5 are used as raw materials, with the purity of SnO2 being greater than 99.5% and the purity of Sb2O5 being greater than 92%.

[0041] 1.2 Preparation of the inner solid solution

[0042] The tin-antimony solid solution is synthesized through solid-phase reaction. The proportioned raw materials are placed in a zirconia ball mill tank for mixing and ball milling. The material-ball ratio is set as material:ball:water = 1.0:1.7:1.0, and the rotation speed is set at 200 - 230 rpm. A composite large and small ball system is adopted, with zirconia balls of φ5 mm, φ3 mm, and φ1 mm in a mass ratio of 1:1:2. The large balls mainly provide impact force to break particles, while the small balls refine the surface through friction to form a coarse particle skeleton;

[0043] The ball milling time is set at 4 hours to refine the powder to D50 ≤ 5 μm, retaining some micron-level pores to facilitate the formation of a high-concentration conductive network in the inner layer during subsequent glazing;

[0044] Sodium dodecylbenzenesulfonate (0.5 - 1 wt%) is added during ball milling as a surfactant to reduce powder agglomeration and ensure uniform distribution.

[0045] After ball milling, it is dried at 80°C for 30 minutes, then placed in a sintering furnace, heated to 1200°C, held for 1 hour, and then cooled naturally.

[0046] 1.3 Preparation of the outer solid solution

[0047] The proportioned raw materials are placed in a zirconia ball mill tank for mixing and ball milling. The material-ball ratio is set as material:ball:solvent = 1.0:1.7:1.0, and the rotation speed is set at 300 - 350 rpm. A composite large and small ball system is adopted, with zirconia balls of φ5 mm, φ3 mm, and φ1 mm in a mass ratio of 1:1:3. The ball milling time is increased to 8 hours, and high shear force is used to further refine to D50 ≤ 2 μm;

[0048] The ball milling solvent is changed to an ethanol-water mixed solvent with a set volume ratio of 3:1 as the dispersion medium to reduce the viscosity of the slurry and promote the uniform dispersion of nano-level particles.

[0049] During ball milling, nitrogen is introduced into the ball mill tank for protection to avoid oxidation reactions of metal oxides during long-term ball milling and maintain the stable doping state.

[0050] After ball milling, it is dried at 80°C for 30 minutes, then placed in a sintering furnace, heated to 1200°C, held for 1 hour, and then cooled naturally.

[0051] In the above steps, the ball milling process converts mechanical energy into chemical energy through the collision of grinding balls, triggering lattice distortion and defect generation. The inner solid solution can form sub-grain boundaries through dislocation slip, while the outer solid solution realizes in solid solution doping in the lattice to form p-type semiconductor characteristics; due to the smaller specific surface area of the inner solid solution, the Sn / Sb doping concentration per unit volume is relatively high, forming a low-resistivity conductive channel; due to the high specific surface area of the outer solid solution, the surface active sites increase, and heterojunctions can be formed by combining with the subsequent doping of photocatalytic materials, realizing a leap in resistivity gradient; in addition, the outer solid solution nanoparticles are regulated by the surface Zeta potential, so that they are preferentially adsorbed in the pores of the coarse particles of the inner solid solution during glazing, forming a dense gradient interface to inhibit the mutual diffusion of elements during the sintering process.

[0052] 2. Selection ratio of base glaze and preparation of multi-layer glaze

[0053] 2.1 Selection ratio of base glaze

[0054] The base glaze material needs to provide a stable crystal phase structure and a framework function at high temperatures, and also needs to provide certain rheological properties and a fluxing function. Combining the composition of the doped phase of the present invention, zirconium white frit, feldspar, and Xiangtan clay are selected as the raw materials for the base glaze, and the ratio is set at 40:45:15 by weight. The chemical compositions of zirconium white frit, feldspar, and Xiangtan clay are shown in Table 1:

[0055] Table 1 Chemical compositions of zirconium white frit, feldspar, and Xiangtan clay (wt%)

[0056]

[0057] "Others" in Table 1 represents the sum of substances with relatively low contents other than the main components, such as trace metal elements, etc. "Loss on ignition" in Table 1 represents the percentage of mass lost by the raw material during high-temperature calcination. The calculation method is as follows: the raw material is calcined at 1000°C until it reaches a constant weight, and the reduced mass is the loss on ignition. The ratio of the loss on ignition to the total mass of the raw material is the "loss on ignition" in Table 1; during the calcination process, the volatilized substances include carbon dioxide, combined water, and small amounts of sulfur, fluorine, chlorine, and organic matter, etc. The "loss on ignition" values in Table 1 are from the experience records and calculations accumulated during long-term sintering work.

[0058] Based on the above ratio and composition, it can be seen that zirconium white frit serves as the glaze framework, providing a stable crystal phase structure at high temperatures, and at the same time participating in the formation of the conductive network of the tin-antimony solid solution; feldspar, as the main flux, reduces the melting temperature of the glaze, promotes the formation of the liquid phase to wrap the conductive phase, and adjusts the viscosity of the glaze to avoid bubble residue; Xiangtan clay 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 zirconium white frit to feldspar is close to 1:1, which can balance the high-temperature stability and melting characteristics. The Xiangtan clay is controlled within 20% to avoid excessive addition resulting in increased brittleness of the glaze layer.

[0059] 2.2 Preparation of multi-layer glaze

[0060] In order to achieve the improvement of comprehensive performance, subsequent stratified gradient glazing will be carried out. The glaze layer includes a bottom glaze layer doped with an inner layer solid solution, a middle glaze layer doped with an outer layer solid solution, and a surface glaze layer doped with the photocatalytic material molybdenum trioxide. The preparation ratios of the bottom glaze layer, the middle glaze layer, and the surface glaze layer vary according to the total ratio set at the beginning of the raw materials.

[0061] The preparation of the glaze is to mix and grind the dopants and base glaze of each glaze layer, add a solvent to adjust it into a glaze slurry with a viscosity of 400 - 600 mPa·s (calibrated with a Brookfield viscometer), then add the corresponding proportion of flux and 0.1wt% sodium carboxymethyl cellulose (CMC), and then mix and stir. The stirring rate is set at 500 rpm and the stirring time is set at 40 minutes.

[0062] 3. Rotating spray stratified glazing

[0063] 3.1 Equipment configuration and parameter setting

[0064] Rotating spray system: The rotation speed of the spray gun is controlled at 800 - 1200 rpm, and the spraying distance is set at 20 - 30 cm to ensure the atomization effect of the glaze slurry and control the atomization particle size ≤ 50 μm; the glaze slurry storage tank is kept at a constant temperature of 25 ± 2°C, and the spraying environment humidity ≥ 60% to prevent uneven drying of the glaze layer; the spraying thickness of different glaze layers is set as follows: the bottom glaze layer is 200 - 300 μm, the middle glaze layer is 400 - 600 μm, and the surface glaze layer is 30 - 50 μm.

[0065] 3.2 Spraying of the bottom glaze layer slurry

[0066] The spraying path adopts a spiral progressive spraying. Coating the entire surface of the blank is counted as one cycle, and the thickness of each cycle of coating is controlled at 20 - 30 μm; immediately after spraying, rapid drying is carried out, and the drying temperature is set at 80 - 100°C and the drying time is 5 minutes. Through rapid drying, microcracks in the glaze layer can be eliminated and the porosity can be reduced.

[0067] 3.3 Spraying of the middle glaze layer slurry

[0068] When spraying the middle glaze layer, the path setting and periodic thickness control are the same as those when spraying the bottom glaze layer above. The difference is that when spraying the middle glaze layer, a gradient dilution process is adopted. The glaze material is gradient-diluted and sprayed through a mixing device. After spraying every 100 μm, 10% diluent is added. The diluent is prepared by mixing deionized water and ethylene glycol in a volume ratio of 1:1, so as to keep the surface resistance relatively high while maintaining the performance of the uniform electric field and micro-channel of the semiconductor, and control the surface current during use within a suitable range; the spraying interval time of different concentration layers is controlled ≤ 3 minutes to improve the interfacial shear strength. After spraying is completed, rapid drying is carried out immediately. The drying temperature is set at 80 - 100 °C, and the drying time is 8 minutes.

[0069] 3.4 Glaze Slurry Spraying of the Surface Glaze Layer

[0070] When spraying the surface glaze layer, the path setting is the same as that of the previous two layers. The thickness of each cycle of coating is controlled at 5 - 10 μm. After spraying is completed, rapid drying is carried out immediately. The drying temperature is set at 80 - 100 °C, and the drying time is 2 minutes.

[0071] In the above steps, a gradient resistance distribution that gradually increases from the inside to the outside is formed through the application of different glaze layers. The lower resistance inside can provide a low-resistance channel for carriers, ensuring stable current conduction without local overheating. It also enables the glaze layer to have a negative temperature coefficient effect. When the local electric field is distorted, the temperature in this area rises, resulting in a decrease in resistance, and the current naturally gathers towards the high-field-strength area, forming a self-regulating voltage equalization mechanism; the higher resistance outside can prevent the surface current from being too large, causing electrochemical corrosion of the glaze layer. When there are surface stains, the relatively large surface resistance can form impedance matching with the pollutants, preventing the wet contaminated layer from directly short-circuiting and increasing the pollution flashover voltage; this gradient resistance has a synergistic effect. The low resistance inside ensures current conduction and generates heat, and the moderate surface resistance limits the current intensity, keeping the drying temperature stable above the dew point without damaging the glaze layer; the internal quickly responds to electric field distortion to achieve dynamic voltage equalization, and the relatively high surface resistance suppresses the initial voltage of slip flashover; the internal continuous conductive network avoids local arc ablation, and the relatively large surface resistance reduces the aging of the glaze layer caused by ion migration.

[0072] 4. Sectional Sintering

[0073] 4.1 Oxidizing Atmosphere Sintering

[0074] The starting temperature of sintering is raised to 500 °C at a rate of 5 °C / min and held for 30 minutes to remove residual organic matter, and then raised to 800 °C at a rate of 3 °C / min and held at a constant temperature for 2 hours; the oxidizing atmosphere during sintering uses a mixed gas of air and nitrogen, and the oxygen partial pressure is controlled at 20 - 30%, and the oxygen ratio is precisely controlled through a flow meter.

[0075] The oxidizing atmosphere can promote The filling of oxygen vacancies in the lattice reduces lattice defects and improves the electrical conductivity inside the glaze; by regulating the oxygen partial pressure, the oxidation reaction is maintained to avoid excessive volatilization of Sb.

[0076] 4.2 Reduction atmosphere sintering

[0077] The sintering atmosphere is switched to a reducing atmosphere. A nitrogen-hydrogen mixture is used, and the hydrogen ratio is controlled at 3-5%. During sintering, it is heated to 1100 °C at 2 °C / min and held at a constant temperature for 1 hour, and then heated to 1150 °C and held for 1 hour to complete sintering.

[0078] The reduction effect of hydrogen in the atmosphere inhibits further oxidation and promotes the migration of lithium ions to the grain boundaries. The and formed by the flux form a eutectic glass phase at 950 °C ( ). This liquid phase fills the grain boundary pores, further reduces the porosity, and at the same time reduces the temperature required for sintering to be completed.

[0079] 4.3 Cooling

[0080] After sintering, it is slowly cooled to 800 °C at 1 °C / min, and then naturally cooled to room temperature to avoid cracking caused by thermal stress. Nitrogen protection is maintained during the cooling stage to prevent re-oxidation.

[0081] In the above steps, MoO3 reacts with in the matrix to form a Mo-Si-O glass phase. The glass phase can form a chemical bond with the matrix, which is beneficial to improving the mechanical strength; during reduction atmosphere sintering, the surface oxygen vacancy concentration increases, forming a p-n heterojunction with the n-type characteristics of MoO3, which helps to improve the photocurrent density.

[0082] Example 1

[0083] The tin-antimony gradient-doped insulating semiconductor glaze and its low-temperature sintering process are as follows:

[0084] The glaze composition includes: 10 wt% of tin-antimony solid solution, 79 wt% of base glaze, 3 wt% of photocatalyst, and 8 wt% of flux; among them, the weight ratio of SnO2 and Sb2O5 in the tin-antimony solid solution is 92:8; the weight ratio of zircon white frit, feldspar and Xiangtan clay in the base glaze is 40:45:15; the weight ratio of the flux spodumene and borax is 5:3, and the photocatalyst is molybdenum trioxide (MoO3).

[0085] The preparation process includes:

[0086] S1: Prepare the tin-antimony solid solution through solid-phase reaction. First, prepare the inner-layer solid solution. Ball-mill the tin dioxide and antimony pentoxide raw materials. Set the ball-milling time to 4 hours. After ball-milling, dry at 80 °C for 30 minutes, then place it in a sintering furnace, heat up 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. Set the ball-milling time to 8 hours. Introduce nitrogen for protection during ball-milling. After ball-milling, dry and sinter under the same conditions as the aforementioned inner-layer solid solution.

[0087] S2: Mix and grind the base glaze with the inner-layer solid solution, outer-layer solid solution and doped photocatalyst respectively. Add a solvent to make a glaze slurry with a viscosity of 400 - 600 mPa·s. Then add a flux and 0.1 wt% sodium carboxymethylcellulose, and mix and stir again. Set the stirring rate to 500 rpm and the stirring time to 40 minutes to prepare the glaze materials for the bottom glaze layer, middle glaze layer and surface glaze layer.

[0088] S3: First, spray the bottom glaze layer with a thickness of 250 μm, and dry at 80 - 100 °C for 5 minutes after spraying. Then spray the middle glaze layer with a thickness of 500 μm. When spraying, add 10% diluent for each 100 μm spraying to form gradient spraying, and dry for 8 minutes under the same conditions as the bottom glaze layer after spraying. Finally, spray the surface glaze layer with a thickness of 40 μm, and dry for 2 minutes under the same conditions as the bottom glaze layer after spraying.

[0089] S4: First, sinter in an air-nitrogen mixed atmosphere. The starting temperature is raised to 500 °C at a rate of 5 °C / min and kept warm for 30 minutes, then raised to 800 °C at a rate of 3 °C / min and kept at a constant temperature for 2 hours. Then sinter in a nitrogen-hydrogen mixed atmosphere. When sintering, raise the temperature to 1100 °C at a rate of 2 °C / min and keep at a constant temperature for 1 hour, and then raise the temperature to 1150 °C and keep warm for 1 hour to complete the sintering. After sintering, cool slowly to 800 °C at a rate of 1 °C / min, and then cool naturally to room temperature to obtain the tin-antimony gradient-doped insulating semiconductor glaze.

[0090] Example 2

[0091] Refer to the glaze composition and preparation process of Example 1, the difference is:

[0092] The glaze composition includes: 8 wt% tin-antimony solid solution, 83 wt% base glaze, 1 wt% photocatalyst, 8 wt% flux, and other compositions remain unchanged.

[0093] In step S3 of the preparation process, spray the bottom glaze layer with a thickness of 200 μm, spray the middle glaze layer with a thickness of 400 μm, and 30 μm, and other steps are the same.

[0094] Example 3

[0095] Refer to the glaze composition and preparation process of Example 1, the difference is:

[0096] The glaze composition includes: 11 wt% of tin-antimony solid solution, 76 wt% of base glaze, 5 wt% of photocatalyst, 8 wt% of flux, and other components remain unchanged.

[0097] In step S3 of the preparation process, the bottom glaze layer is sprayed with a thickness of 300 μm, the middle glaze layer is sprayed with a thickness of 600 μm, and the surface glaze layer is sprayed with a thickness of 50 μm, and other steps are the same.

[0098] Example 4

[0099] Referring to the glaze composition and preparation process of Example 1, the differences are as follows:

[0100] The glaze composition includes: 9 wt% of tin-antimony solid solution, 81 wt% of base glaze, 2 wt% of photocatalyst, 8 wt% of flux, and other components remain unchanged.

[0101] In step S3 of the preparation process, the bottom glaze layer is sprayed with a thickness of 230 μm, the middle glaze layer is sprayed with a thickness of 450 μm, and the surface glaze layer is sprayed with a thickness of 35 μm, and other steps are the same.

[0102] Example 5

[0103] Referring to the glaze composition and preparation process of Example 1, the differences are as follows:

[0104] The glaze composition includes: 10 wt% of tin-antimony solid solution, 78 wt% of base glaze, 4 wt% of photocatalyst, 8 wt% of flux, and other components remain unchanged.

[0105] In step S3 of the preparation process, the bottom glaze layer is sprayed with a thickness of 280 μm, the middle glaze layer is sprayed with a thickness of 550 μm, and the surface glaze layer is sprayed with a thickness of 45 μm, and other steps are the same.

[0106] Comparative Example 1

[0107] Referring to the preparation steps of Example 1, the differences are as follows: in step S1, only the outer solid solution is prepared; in step S2, only the glazes for the middle glaze layer and the surface glaze layer are formulated; in step S3, the gradient spraying method is not used for glaze spraying; and other steps are the same.

[0108] Comparative Example 2

[0109] Referring to the preparation steps of Example 1, the differences are as follows: the flux is not included in the glaze composition, and the proportion originally occupied by the flux is added to the base glaze; in step S2, the step of sintering in a nitrogen-hydrogen mixed atmosphere is changed to: heating to 1200 °C at a rate of 2 °C / min and holding for 1 hour, and then heating to 1300 °C and holding for 1 hour to complete sintering.

[0110] Experimental Example 1

[0111] Samples were taken from the inner solid solution and the outer solid solution prepared in step S1 of Example 1, and a laser particle size analyzer was used to test the particle size distribution of the solid solutions prepared under different ball milling conditions for the two layers. Specifically, it was carried out with reference to the national standard GB / T 19077-2024 "Particle Size Analysis - Laser Diffraction Method".

[0112] As shown in the appendix Figure 2 and the appendix Figure 3 , respectively showing the volume percentage and cumulative volume percentage distributions of the particle sizes of the inner solid solution and the outer solid solution. Through result analysis, it can be sorted out that D50 of the inner solid solution ≤ 5 μm and D50 of the outer solid solution ≤ 2 μm.

[0113] Experimental Example 2

[0114] Separate samples of the tin-antimony gradient-doped insulating semiconductor glaze layer were prepared according to Example 1 for optical property tests, including ultraviolet-visible diffuse reflection and photocatalytic self-cleaning property tests. For the ultraviolet-visible diffuse reflection test, a ultraviolet-visible diffuse reflection spectrophotometer was used to test the diffuse reflection spectrum of the sample; for the photocatalytic self-cleaning property test, with reference to the national standard GB / T 23762-2009 "Test Method for Photocatalytic Self-Cleaning Material Performance", the degradation rate of diatomite was tested under ultraviolet light irradiation (365 nm, 1000 W / m²) to simulate the pollutant decomposition ability of the glaze layer under wet pollution.

[0115] The results of the ultraviolet-visible light diffuse reflection test are as shown in the appendix Figure 4 . As can be seen from the figure, except for the ultraviolet band, after molybdenum trioxide is doped in the surface glaze, photocatalytic substances can be formed, which have rich electronic energy levels, have a certain absorption of visible light, and promote the photocatalytic degradation reaction on the surface layer.

[0116] The results of the photocatalytic self-cleaning property test show that within 8 hours, the degradation rate of diatomite of the sample under ultraviolet light irradiation ≥ 85%, meeting the self-cleaning requirements of the surface glaze under pollution conditions.

[0117] Experimental Example 3

[0118] 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 green body respectively, and then the volume resistivity of the homogeneous glaze layers of different examples or comparative examples, the surface pollution flashover voltage of the whole glaze layer, and the mechanical properties of the whole glaze layer were tested respectively.

[0119] The formulation composition of the embryo body is shown in Table 2. The volume resistivity is measured by the direct current (DC) method with reference to the national standard GB / T 31838.2-2019. When measuring, for Examples 1 to 5, the resistivity of the separate body after sintering under the same conditions of S4 for the bottom glaze layer, the middle glaze layer, and the surface glaze layer is measured respectively; for Comparative Example 1, the resistivity of the separate body after sintering under the same conditions of S4 for the middle glaze layer and the surface glaze layer (without the bottom glaze layer) is measured respectively; for Comparative Example 2, the resistivity of the separate body after sintering under its different sintering conditions for the bottom glaze layer, the middle glaze layer, and the surface glaze layer is measured respectively; for data acquisition, 50 data are collected for each separate glaze layer, and the average data magnitude of its resistivity is obtained after statistics and recorded for comparison;

[0120] The surface pollution flashover voltage refers to the standard IEC 60507:2013 "Artificial Pollution Tests", simulates a salt spray environment (5% NaCl), and tests the pollution flashover voltage; the mechanical properties refer to the national standard GB6569-2006 "Test Method for Flexural Strength of Fine Ceramics" to conduct a three-point bending test to test the flexural strength of the glaze layer. The test comparison results are shown in Table 3.

[0121] Table 2 Formulation chemical composition table of the embryo body (wt%)

[0122]

[0123] The "loss on ignition" in Table 2 has the same meaning as the "loss on ignition" in Table 1 mentioned above. The value of "loss on ignition" in Table 2 comes from the experience records and calculations accumulated in long-term sintering work.

[0124] Table 3 Comparison table of experimental results of Examples 1-5 and Comparative Examples 1-2 in Experimental Example 3

[0125]

[0126] From the above comparison results, it can be seen that in Comparative Example 1, the gradient layered glaze system is not adopted, resulting in a small difference in resistivity inside and outside the glaze layer, and the various functions realized by the gradient resistivity cannot be achieved, resulting in a decrease in the pollution flashover voltage; in Comparative Example 2, no flux is used, so the sintering temperature has to be increased during the subsequent sintering, which affects the overall densification of the glaze layer, resulting in a decline in the overall performance, especially the decline in mechanical properties. In addition, the high sintering temperature will cause excessive volatilization of MoO3, affecting the surface photocatalytic self-cleaning performance.

Claims

1. Tin-antimony gradient doped insulating semiconductor glaze, characterized in that, It contains the following components: 8-11 wt% of tin-antimony solid solution, 76-83 wt% of base glaze, 1-5 wt% of photocatalytic material, and 8 wt% of fluxing agent, and is prepared by a low-temperature sintering process. The low-temperature sintering process includes the following steps: S1: Prepare the tin-antimony solid solution. Inner slurry and outer slurry are respectively prepared by different ball-milling processes. After ball-milling, they are dried at 80 °C for 30 minutes respectively, then placed in a sintering furnace, heated to 1200 °C, held for 1 hour and then naturally cooled to obtain inner-layer tin-antimony solid solution and outer-layer tin-antimony solid solution; S2: Configure the base glaze, and mix and grind 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 photocatalytic material respectively, add a solvent for modulation, and then add the fluxing agent and mix and stir to obtain bottom-glaze layer glaze slurry, middle-glaze layer glaze slurry and surface-glaze layer glaze slurry respectively; S3: Rotate and spray the bottom-glaze layer glaze slurry. After spraying is completed, conduct the first rapid drying. Rotate and spray the middle-glaze layer glaze slurry on the sprayed bottom-glaze layer. After spraying is completed, conduct the second rapid drying. Rotate and spray the surface-glaze layer glaze slurry on the sprayed middle-glaze layer. After spraying is completed, conduct the third rapid drying to obtain multi-layer glaze; S4: Sinter the multi-layer glaze sprayed in S3 successively in an oxidizing atmosphere and a reducing atmosphere, and cool it after sintering to obtain tin-antimony gradient-doped insulating semiconductor glaze.

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 with a weight ratio of 92:

8.

3. The tin-antimony gradient-doped insulating semiconductor glaze according to claim 1, wherein The base glaze consists of zircon white frit, feldspar and Xiangtan clay, with a weight ratio of 40:45:

15.

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

3.

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

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

3.

7. The tin-antimony gradient-doped insulating semiconductor glaze according to claim 1, characterized in that For the addition of solvent for modulation in S2, the modulated viscosity is 400-600 mPa·s; For the mixing and stirring in S2, the parameter setting is to stir at a speed of 500 rpm for 40 minutes.

8. The tin-antimony gradient-doped insulating semiconductor glaze according to claim 1, characterized in that The thickness of the sprayed bottom-glaze layer glaze slurry in S3 is 200-300 μm, the thickness of the sprayed middle-glaze layer glaze slurry is 400-600 μm, and the thickness of the sprayed surface-glaze layer glaze slurry is 30-50 μm; For the glaze slurry in the rotary spraying described in S3, when spraying, add 10% diluent for every 100 μm sprayed and then continue spraying; For 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 times are 5 minutes, 8 minutes and 2 minutes in sequence.

9. The stannum-antimony gradient-doped insulating semiconductor glaze according to claim 1, wherein For the sintering in an oxidizing atmosphere described in S4, it specifically includes that the starting temperature of sintering is raised to 500 °C at a rate of 5 °C / min and held for 30 minutes, then raised to 800 °C at a rate of 3 °C / min and kept constant for 2 hours. The sintering atmosphere uses a mixed gas of air and nitrogen, and the oxygen partial pressure is controlled at 20 - 30%; For the sintering in a reducing atmosphere described in S4, it specifically includes that the starting temperature of sintering is raised to 1100 °C at a rate of 2 °C / min and held constant for 1 hour, then raised to 1150 °C and held for 1 hour. The sintering atmosphere uses a mixed gas of nitrogen - hydrogen, and the proportion of hydrogen is controlled at 3 - 5%; For the cooling after sintering described in S4, it specifically includes slow cooling to 800 °C at a rate of 1 °C / min, and then natural cooling to room temperature.

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