A high-temperature-resistant aluminum oxide ceramic insulator and a preparation method thereof

Abstract

The application relates to the technical field of special ceramic insulator preparation, in particular to a high-temperature-resistant alumina ceramic insulator and a preparation method thereof. The high-temperature-resistant alumina ceramic insulator is prepared from raw materials with the following mass percentages: 1-10% of a sintering aid, 0.5-5% of toughening combined fillers, and the balance of alumina aggregate; the sintering aid is composed of at least one of zirconium oxide, rare earth oxide, calcium oxide, magnesium oxide, silicon dioxide, manganese dioxide and titanium dioxide; the rare earth oxide is at least one of yttrium oxide, lanthanum oxide, samarium oxide and cerium oxide; and the toughening combined fillers are one or a combination of multiple kinds of alumina whiskers, zinc oxide whiskers, zirconium oxide whiskers, aluminum nitride whiskers, silicon nitride crystal forms and potassium titanate whiskers. The high-temperature-resistant alumina ceramic insulator has excellent compressive strength and tensile strength and good impact toughness, and can meet the performance requirements of an insulator of an extra-high voltage power transmission network.

Description

Technical Field

[0001] This invention relates to the field of special ceramic insulator preparation technology, and in particular to a high-temperature resistant alumina ceramic insulator and its preparation method. Background Technology

[0002] With the development of power infrastructure, power transmission networks have evolved from 35-500kV high-voltage transmission to 500-1000kV ultra-high-voltage transmission. Ceramic insulators are crucial components of power systems, serving functions such as conductor isolation, support, and fixation. As power transmission networks expand towards ultra-high-voltage transmission, higher demands are placed on the physical and chemical properties of ceramic insulators used in power transmission. For example, ceramic insulators in ultra-high-voltage transmission networks are subjected to stronger electric fields and greater mechanical stresses, requiring higher tensile strength, compressive strength, impact toughness, and thermal stability.

[0003] Currently, porcelain insulators are mainly made from feldspar, quartz, and clay as the main raw materials. The diverse composition of these insulators affects their overall thermodynamic properties, resulting in significant axial compressive stress and tangential shear stress. This leads to poor impact toughness, making them unsuitable for ultra-high voltage power transmission. Under strong electric fields and high mechanical stress, these porcelain insulators will eventually develop internal and / or surface cracks when they reach their withstand threshold, affecting their overall mechanical properties, service life, and safety. Therefore, there is an urgent need for a high-temperature resistant alumina ceramic insulator and its preparation method. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a high-temperature resistant alumina ceramic insulator and its preparation method.

[0005] The high-temperature resistant alumina ceramic insulator provided by this invention is achieved through the following technical solution:

[0006] A high-temperature resistant alumina ceramic insulator is made from the following raw materials in the indicated weight percentages: 1-10% sintering aid, 0.5-5% toughening composite filler, and the balance alumina aggregate; the sintering aid is composed of at least one of zirconium oxide, rare earth oxides, calcium oxide, magnesium oxide, silicon dioxide, manganese dioxide, and titanium dioxide; the rare earth oxide is at least one of yttrium oxide, lanthanum oxide, samarium oxide, and cerium oxide; the toughening composite filler is one or more of alumina whiskers, zinc oxide whiskers, zirconium oxide whiskers, aluminum nitride whiskers, silicon nitride crystals, and potassium titanate whiskers.

[0007] Zirconia in the sintering aid forms tetragonal zirconia (t-ZrO2) with at least one of calcium oxide, magnesium oxide, yttrium oxide, silicon dioxide, manganese dioxide, titanium dioxide, lanthanum oxide, samarium oxide, and cerium oxide during sintering. Under stress, t-ZrO2 undergoes a stress-induced phase transformation, relaxing the stress field at the crack tip, increasing crack propagation resistance, and effectively improving overall flexural strength and impact toughness. Calcium oxide in the sintering aid undergoes eutectic reaction with alumina during sintering, which is beneficial for solid-state reactions. Magnesium oxide becomes a nucleus for crystal growth during sintering, which helps eliminate large voids in the preform, promotes densification, and inhibits crystal growth. Adding a small amount of rare earth oxides (at least one of lanthanum oxide, samarium oxide, cerium oxide, and yttrium oxide) can promote the reaction of alumina with other sintering aid components to form a liquid phase with a lower melting point, effectively reducing its sintering temperature. Through the capillary action of the grain gaps, the liquid phase fills the voids, densifying the ceramic and improving its overall mechanical properties and impact toughness. Titanium dioxide can reduce the viscosity of the liquid phase and promote sintering; silicon dioxide, by filling the pores between alumina crystals, improves the grain boundary bonding force, significantly enhancing the compressive strength and wear resistance of the ceramic, reducing the coefficient of thermal expansion, reducing thermal stress, and enhancing thermal shock resistance. At high temperatures, it generates a liquid phase, promoting grain refinement, lowering the sintering temperature, and increasing the bulk density. Furthermore, under the action of titanium dioxide, it can react with alumina during sintering to form mullite, promoting crystal growth and improving the overall wear resistance, hardness, and mechanical properties. High-insulation inorganic whiskers are used as the toughening and reinforcing phase in the toughening composite filler, which can effectively improve the overall compressive strength, tensile strength and impact toughness. The high-temperature resistant alumina ceramic insulators made by compounding alumina aggregate with a specific ratio of sintering aids and toughening composite fillers have excellent mechanical properties and impact toughness, which can meet the performance requirements of UHV power transmission networks for insulators.

[0008] Preferably, the alumina aggregate consists of a median diameter D 50 α-alumina with a diameter of X μm and a median diameter D 50 α-alumina with a diameter of Y μm and a median diameter D 50 α-alumina with a diameter of Z μm is composed of a mass ratio of (60-68):(24-28):(8-12); wherein the ratio of X:Y:Z is 1:(0.40-0.42):(0.22-0.23).

[0009] Preferably, the alumina aggregate consists of a median diameter D 50 α-alumina with a diameter of X μm and a median diameter D 50 α-alumina with a diameter of Y μm and a median diameter D 50 The α-alumina with a diameter of Z μm is composed of a mass ratio of 66:25:9.

[0010] Preferably, the alumina aggregate consists of a median diameter D 50α-alumina with a diameter of 1.0-1.20 μm and a median diameter D 50 α-alumina with a diameter of 0.40-0.50 μm and a median diameter D 50 The α-alumina with a size of 0.22-0.27 μm is composed of a mass ratio of 66:25:9.

[0011] Optimizing the gradation of α-alumina can effectively improve the density of high-temperature alumina ceramic insulators, thereby improving the overall mechanical properties and impact toughness of the high-temperature alumina ceramic insulators and meeting the performance requirements of UHV transmission networks for insulators.

[0012] Preferably, the sintering aid is composed of zirconium oxide, calcium oxide, magnesium oxide, yttrium oxide, lanthanum oxide, and silicon dioxide.

[0013] More preferably, the mass ratio of the zirconium oxide to the calcium oxide, the magnesium oxide, the yttrium oxide, the lanthanum oxide, and the silicon dioxide is (4-10):1:1:1:(1-4):1.

[0014] By compounding sintering aids, the sintering temperature can be effectively reduced, the pores between alumina crystals can be filled, the grain boundary bonding force can be improved, the grain refinement can be promoted, and the wear resistance, mechanical properties, impact toughness and thermal shock resistance of high-temperature alumina ceramic insulators can be improved, so as to better meet the performance requirements of UHV power transmission networks for insulators.

[0015] Preferably, the toughening composite filler is composed of zinc oxide whiskers, zirconium oxide whiskers, and potassium titanate whiskers, with the mass ratio of zinc oxide whiskers to zirconium oxide whiskers and potassium titanate whiskers being (0.1-0.4):(1-2):(0.5-2).

[0016] Toughening composite fillers formed by combining zinc oxide whiskers, zirconium oxide whiskers, and potassium titanate whiskers with high aspect ratios can effectively improve mechanical properties, impact toughness, and thermal shock resistance. It is important to note that zinc oxide whiskers are semiconductors, and their addition must be strictly controlled; excessive addition can affect the insulation safety performance of high-temperature alumina ceramic insulators. To overcome the insulation safety risks associated with excessive zinc oxide whisker addition, the inventors performed surface modification treatment on the zinc oxide whiskers. Through self-assembly technology, aluminum hydroxide was deposited on the surface of the zinc oxide whiskers, followed by a calcination reaction to form nano-alumina on the surface. The resulting Al2O3@T-ZnO is no longer limited by the amount added, and while ensuring the insulation safety performance of high-temperature alumina ceramic insulators, it can effectively improve the density, flexural strength, heat resistance, and impact toughness of high-temperature alumina ceramic insulators.

[0017] Preferably, the high-temperature resistant alumina ceramic insulator is made of 3-4 wt% zirconium oxide, 0.4-0.6 wt% calcium oxide, 0.4-0.6 wt% magnesium oxide, 0.4-0.6 wt% yttrium oxide, 0.4-2.0 wt% lanthanum oxide, 0.4-0.6 wt% silicon dioxide, 0.2-0.8 wt% zinc oxide whiskers, 1.0-3.0 wt% zirconium oxide whiskers, 0.2-0.8 wt% potassium titanate crystals, and the balance being alumina aggregate.

[0018] More preferably, the high-temperature resistant alumina ceramic insulator is composed of 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystal form, and 60.72 wt% median diameter D. 50 It is α-alumina with a thickness of 1.0-1.20 μm and a median diameter D of 23.0 wt%. 50 It has an α-alumina size of 0.40-0.50 μm and a median diameter D of 8.28 wt%. 50 It is made of α-alumina with a thickness of 0.22-0.27 μm.

[0019] By adopting the above technical solution, high-performance high-temperature resistant alumina ceramic insulators can be prepared, which can better meet the performance requirements of UHV power transmission networks for insulators.

[0020] The method for preparing high-temperature resistant alumina ceramic insulators provided by this invention is achieved through the following technical solution:

[0021] A method for preparing a high-temperature resistant alumina ceramic insulator includes the following steps:

[0022] Step 1, Preparation of alumina aggregate: The median diameter D... 50 α-alumina with a diameter of 1.0-1.20 μm and a median diameter D 50 α-alumina with a diameter of 0.40-0.50 μm and a median diameter D 50 α-alumina with a particle size of 0.22-0.27 μm can be obtained by mixing it evenly according to the formula;

[0023] Simultaneously, a compounding agent for sintering is prepared: zirconium oxide, calcium oxide, magnesium oxide, yttrium oxide, lanthanum oxide, and silicon dioxide are mixed evenly according to the formula to obtain the desired product;

[0024] Simultaneously, the toughening composite filler is prepared by mixing zinc oxide whiskers, zirconium oxide whiskers, and potassium titanate whiskers evenly according to the formula.

[0025] Step 2: Place the sintering aid, toughening composite filler, and alumina aggregate prepared in Step 1 into a high-speed dispersion kettle, and disperse them at a high speed of 400-600 r / min for 4-6 h under nitrogen protection. After thorough mixing, the insulator ceramic material composition can be obtained.

[0026] Step 3: The insulator porcelain material composition in Step 2 is mixed with polyvinyl alcohol binder at a mass ratio of 100:(6-8) and granulated. The resulting granules are sieved through a 40-80 mesh screen to obtain spherical insulator granules sieved through a 40-80 mesh screen.

[0027] Step four: Place the insulator spherical granules prepared in step three into a molding die and obtain a rough blank through isostatic pressing.

[0028] Step 5: Perform spark plasma sintering on the rough blank from Step 4 to obtain the finished high-temperature resistant alumina ceramic insulator.

[0029] The preparation method provided by this invention is relatively simple, the process is mature, it is easy to realize industrial production, and the quality of the finished product is guaranteed.

[0030] Preferably, in step five, the rough blank from step four is placed in a spark plasma sintering furnace, the vacuum degree is adjusted to ≤10Pa, the pressure is 6-9MPa, the temperature is first raised to 1020-1060℃ at a heating rate of 100-250℃ / min, then the heating rate is adjusted to 25-50℃ / min to raise the temperature to 1550-1650℃ and held for 2-4h, then the temperature is adjusted to 1020-1060℃ at a cooling rate of 400-600℃ / h and held for 0.5-2h, and finally the temperature is adjusted to 800-850℃ at a cooling rate of 400-600℃ / h, the furnace is opened and the blank is allowed to cool naturally to room temperature, and then demolded to obtain the finished high-temperature resistant alumina ceramic insulator.

[0031] By optimizing the parameters of the spark plasma sintering (SPS) process, the density of high-temperature alumina ceramic insulators can be improved and internal stress can be effectively released, thereby improving the mechanical properties and impact toughness of the finished high-temperature alumina ceramic insulators.

[0032] In summary, the present invention has the following advantages:

[0033] 1. This invention has excellent wear resistance, compressive strength, tensile strength, thermal shock resistance and good impact toughness, which can meet the performance requirements of UHV power transmission networks for insulators.

[0034] 2. The preparation method provided by this invention is relatively simple and the process is mature, which facilitates industrial production and can ensure the quality stability of high-temperature resistant alumina ceramic insulators in the same batch, thereby enhancing the core competitiveness of the product. Detailed Implementation

[0035] To further understand the inventiveness and technical advancements of this invention, the preferred embodiments of this invention will be discussed in detail below with reference to examples and comparative examples.

[0036] Example: A high-temperature resistant alumina ceramic insulator is made from the following raw materials in weight percentages: 1-10% sintering aid, 0.5-5% toughening composite filler, and the balance alumina aggregate.

[0037] Alumina aggregate consists of median diameter D 50 α-alumina with a diameter of X μm and a median diameter D 50 α-alumina with a diameter of Y μm and a median diameter D 50 α-alumina with a diameter of Z μm was composed of a mass ratio of (60-68):(24-28):(8-12). Among them, three different median diameters D... 50 The X:Y:Z ratio of α-alumina is 1:(0.4-0.42):(0.22-0.23), and the overall density is optimized through gradation.

[0038] Preferably, the alumina aggregate consists of a median diameter D 50 α-alumina with a diameter of X μm and a median diameter D 50 α-alumina with a diameter of Y μm and a median diameter D 50 The α-alumina with a diameter of Z μm is composed of a mass ratio of 66:25:9.

[0039] Specifically, the alumina aggregate consists of a median diameter D 50 α-alumina with a diameter of 1.0-1.20 μm and a median diameter D 50 α-alumina with a diameter of 0.40-0.50 μm and a median diameter D 50 The α-alumina with a size of 0.22-0.27 μm is composed of a mass ratio of 66:25:9.

[0040] The sintering aid is composed of zirconium oxide, rare earth oxides, and at least one of calcium oxide, magnesium oxide, silicon dioxide, manganese dioxide, and titanium dioxide. The rare earth oxides are at least one of yttrium oxide, lanthanum oxide, samarium oxide, and cerium oxide.

[0041] Preferably, the sintering aid is composed of zirconium oxide, calcium oxide, magnesium oxide, yttrium oxide, lanthanum oxide, and silicon dioxide.

[0042] Specifically, the sintering aid is composed of zirconium oxide, calcium oxide, magnesium oxide, yttrium oxide, lanthanum oxide, and silicon dioxide in a mass ratio of (4-10):1:1:1:(1-4):1.

[0043] The toughening composite filler is one or more of the following: alumina whiskers, zinc oxide whiskers, zirconia whiskers, aluminum nitride whiskers, silicon nitride, and potassium titanate whiskers. Preferably, the toughening composite filler is composed of zinc oxide whiskers, zirconia whiskers, and potassium titanate whiskers. Specifically, the toughening composite filler is composed of zinc oxide whiskers, zirconia whiskers, and potassium titanate whiskers in a mass ratio of (0.1-0.4):(1-2):(0.5-2).

[0044] The preferred formulation for high-temperature resistant alumina ceramic insulators is as follows, which is made from the following raw materials in the following mass percentages: 3-4 wt% zirconium oxide, 0.4-0.6 wt% calcium oxide, 0.4-0.6 wt% magnesium oxide, 0.4-0.6 wt% yttrium oxide, 0.4-2.0 wt% lanthanum oxide, 0.4-0.6 wt% silicon dioxide, 0.2-0.8 wt% zinc oxide whiskers, 1.0-3.0 wt% zirconium oxide whiskers, 0.2-0.8 wt% potassium titanate crystals, and the balance being alumina aggregate.

[0045] A method for preparing a high-temperature resistant alumina ceramic insulator includes the following steps:

[0046] Step 1, Preparation of alumina aggregate: The median diameter D... 50 α-alumina with a diameter of 1.0-1.20 μm and a median diameter D 50 α-alumina with a diameter of 0.40-0.50 μm and a median diameter D 50 α-alumina with a particle size of 0.22-0.27 μm can be obtained by mixing it evenly according to the formula;

[0047] Simultaneously, a compounding agent for sintering is prepared: zirconium oxide, calcium oxide, magnesium oxide, yttrium oxide, lanthanum oxide, and silicon dioxide are mixed evenly according to the formula to obtain the desired product;

[0048] Simultaneously, the toughening composite filler is prepared by mixing zinc oxide whiskers, zirconium oxide whiskers, and potassium titanate whiskers evenly according to the formula.

[0049] Step 2: Place the sintering aid, toughening composite filler, and alumina aggregate prepared in Step 1 into a high-speed dispersion kettle, and disperse them at a high speed of 400-600 r / min for 4-6 h under nitrogen protection. After thorough mixing, the insulator ceramic material composition can be obtained.

[0050] Step 3: The insulator porcelain material composition in Step 2 is mixed with polyvinyl alcohol binder at a mass ratio of 100:(6-8) and granulated. The resulting granules are sieved through a 40-80 mesh screen to obtain spherical insulator granules sieved through a 40-80 mesh screen.

[0051] Step four: Place the insulator spherical granules prepared in step three into a molding die and obtain a rough blank through isostatic pressing.

[0052] Step 5: Place the rough blank from Step 4 into a spark plasma sintering furnace, adjust the vacuum degree to ≤10Pa, and the pressure to 6-9MPa. First, heat the blank to 1020-1060℃ at a heating rate of 100-250℃ / min, then adjust the heating rate to 25-50℃ / min to heat the blank to 1550-1650℃ and hold for 2-4 hours. Then, adjust the temperature to 1020-1060℃ at a cooling rate of 400-600℃ / min and hold for 0.5-2 hours. Finally, adjust the temperature to 800-850℃ at a cooling rate of 400-600℃ / min. Open the furnace and allow it to cool naturally to room temperature. Demold the blank to obtain the finished high-temperature resistant alumina ceramic insulator.

[0053] Example 1: A high-temperature resistant alumina ceramic insulator is made from the following raw materials in the indicated weight percentages: 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystals, and 92 wt% α-alumina aggregate. The 92 wt% α-alumina aggregate consists of 60.72 wt% α-alumina X, 23.0 wt% α-alumina Y, and 8.28 wt% α-alumina Z. The mass ratio of α-alumina X:α-alumina Y:α-alumina Z is 66:25:9.

[0054] α-Alumina X was obtained by sieving 5000-mesh α-alumina (provided by Lianyungang Wohua New Material Technology Co., Ltd.) through a 5000-mesh sieve. The sieved material was then sieved through a 10000-mesh sieve to obtain the oversize material, which is α-alumina X. The median diameter D was determined using an NS-90Plus nanoparticle size analyzer. 50 The median diameter (D) was 1.18 μm. α-alumina Y, supplied by Suzhou Beike Nanotechnology Co., Ltd., had a particle size of 500 nm and was determined using an NS-90Plus nanoparticle size analyzer. 50 The particle size distribution was 0.491 μm. α-Alumina Z was selected from 6N high-purity alumina powder from Hangzhou Hengna New Materials Co., Ltd., with a particle size distribution of 0.2-0.5 μm. The median diameter D was determined using an NS-90Plus nanoparticle size analyzer. 50 The median diameter D of α-alumina X, α-alumina Y, and α-alumina Z is 0.265 μm. 50 The ratio is X:Y:Z = 1.18:0.491:265 = 100:41.61:22.20.

[0055] Zirconia (XT-ZR02-02, 50nm), magnesium oxide (XT-MG0-02, 40nm), yttrium oxide (XT-Y203-02, 50nm), lanthanum oxide (XT-La203-01, 50nm), and silicon dioxide (XT-S102-02, 50nm) were supplied by Shanghai Xiangtian Nanomaterials Co., Ltd. Calcium oxide (DK-CaO-100) was supplied by Beijing Deco Island Gold Technology Co., Ltd., with a product specification of 100nm.

[0056] Zinc oxide whiskers SS-ZJ50 have a diameter of 0.5-5 μm and a length of 10-50 μm, supplied by Hangzhou Jikang New Materials Co., Ltd., with an apparent density of 0.2±0.1 g / cm³. 3 The actual density is 5.3 ± 0.2 g / cm³. 3 Zirconia whiskers were provided by Hubei Xinyuhong Biomedical Technology Co., Ltd. Potassium titanate whiskers, CAS number 12030-97-6, with diameters of 0.1-0.3 μm and lengths of 5-15 μm, were provided by Wuhan Yuancheng Chemical Co., Ltd.

[0057] A method for preparing a high-temperature resistant alumina ceramic insulator includes the following steps:

[0058] Step 1, Preparation of alumina aggregate: Mix 60.72 parts by weight of alumina aggregate with a median diameter D... 50 α-alumina X with a diameter of 1.18 μm and a median diameter D of 23 parts by weight 50 α-alumina Y with a diameter of 0.491 μm and a median diameter D of 8.28 parts by weight. 50 α-alumina Z with a particle size of 0.265 μm was placed in a high-speed dispersion vessel and dispersed at 400 rpm for 2 hours under nitrogen protection to obtain alumina aggregate.

[0059] Simultaneously, a sintering aid was compounded: 37.5 parts by weight of zirconium oxide, 5 parts by weight of calcium oxide, 5 parts by weight of magnesium oxide, 5 parts by weight of yttrium oxide, 5 parts by weight of lanthanum oxide, and 5 parts by weight of silica were placed in a high-speed dispersion vessel and dispersed at 400 rpm for 2 hours to obtain a compounded sintering aid. The compounded sintering aid was then placed in a planetary ball mill with water as the dispersant and a solid-liquid ratio of 1:2. Tungsten oxide was used as the grinding beads, and the mixture was ball-milled at 200 r / min for 4 hours to refine the material. After drying to remove moisture, the median diameter D was obtained. 50 The finished compound sintering aid has a particle size of 0.685μm;

[0060] Meanwhile, the toughening composite filler was prepared: 2 parts by weight of zinc oxide whiskers, 20 parts by weight of zirconium oxide whiskers and 8 parts by weight of potassium titanate whiskers were placed in a high-speed dispersion kettle and dispersed at 400 rpm for 2 hours under nitrogen protection to obtain the toughening composite filler.

[0061] Step 2: Place the finished compound sintering aid, toughening composite filler and alumina aggregate prepared in Step 1 into a high-speed dispersion kettle, and disperse at 400 r / min for 4 h under nitrogen protection. After thorough mixing, the insulator ceramic material composition is obtained.

[0062] Step 3: The insulator porcelain material composition from Step 2 is mixed with polyvinyl alcohol binder at a mass ratio of 100:7 and granulated. The resulting granules are then sieved through a 60-mesh sieve to obtain spherical insulator granules that pass through the 60-mesh sieve.

[0063] Step 4: Place the insulator spherical granules prepared in Step 3 into a molding mold, and perform isostatic pressing at 120MPa for 15s. Demolding will then yield the rough blank.

[0064] Step 5: Place the rough blank from Step 4 into a spark plasma sintering furnace, adjust the vacuum degree to ≤10Pa and the pressure to 8MPa, first raise the temperature to 1050℃ at a heating rate of 250℃ / min, then adjust the heating rate to 25℃ / min to raise the temperature to 1600℃ and hold for 2 hours, then adjust the temperature to 1050℃ at a cooling rate of 450℃ / h and hold for 0.5-2 hours, and finally adjust the temperature to 850℃ at a cooling rate of 450℃ / h. Open the furnace and allow it to cool naturally to room temperature. Demold the product to obtain the high-temperature resistant alumina ceramic insulator.

[0065] The difference between Example 2 and Example 1 is that the high-temperature resistant alumina ceramic insulator is made from the following raw materials by weight percentage: 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystals, and 92 wt% α-alumina aggregate. The mass ratio of α-alumina X: α-alumina Y: α-alumina Z is 60:30:10.

[0066] The difference between Example 3 and Example 1 is that the high-temperature resistant alumina ceramic insulator is made from the following raw materials by weight percentage: 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystals, and 92 wt% α-alumina aggregate. The mass ratio of α-alumina X: α-alumina Y: α-alumina Z is 50:40:10.

[0067] The difference between Example 4 and Example 1 is that the high-temperature resistant alumina ceramic insulator is made from the following raw materials by weight percentage: 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystals, and 92 wt% α-alumina aggregate. The mass ratio of α-alumina X: α-alumina Y: α-alumina Z is 75:20:5.

[0068] The difference between Example 5 and Example 1 is that the high-temperature resistant alumina ceramic insulator is made from the following raw materials by weight percentage: 2% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystals, and 93.75 wt% α-alumina aggregate. The mass ratio of α-alumina X: α-alumina Y: α-alumina Z is 66:25:9.

[0069] The difference between Example 6 and Example 1 is that the high-temperature resistant alumina ceramic insulator is made from the following raw materials by weight percentage: 3% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystals, and 92.75 wt% α-alumina aggregate. The mass ratio of α-alumina X: α-alumina Y: α-alumina Z is 66:25:9.

[0070] The difference between Example 7 and Example 1 is that the high-temperature resistant alumina ceramic insulator is made from the following raw materials by weight percentage: 5% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystals, and 90.75 wt% α-alumina aggregate. The mass ratio of α-alumina X: α-alumina Y: α-alumina Z is 66:25:9.

[0071] The difference between Example 8 and Example 1 is that the high-temperature resistant alumina ceramic insulator is made from the following raw materials by weight percentage: 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 1.0 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystals, and 91.5 wt% α-alumina aggregate. The mass ratio of α-alumina X:α-alumina Y:α-alumina Z is 66:25:9.

[0072] The difference between Example 9 and Example 1 is that the high-temperature resistant alumina ceramic insulator is made from the following raw materials by weight percentage: 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 1.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystals, and 91 wt% α-alumina aggregate. The mass ratio of α-alumina X: α-alumina Y: α-alumina Z is 66:25:9.

[0073] The difference between Example 10 and Example 1 is that the high-temperature resistant alumina ceramic insulator is made from the following raw materials by weight percentage: 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 2.0 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystals, and 90.5 wt% α-alumina aggregate. The mass ratio of α-alumina X: α-alumina Y: α-alumina Z is 66:25:9.

[0074] The difference between Example 11 and Example 8 is that the high-temperature resistant alumina ceramic insulator is made from the following raw materials by weight percentage: 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 1.0 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 1.25 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystals, and 91.5 wt% α-alumina aggregate. The mass ratio of α-alumina X: α-alumina Y: α-alumina Z is 66:25:9.

[0075] The difference between Example 12 and Example 8 is that the high-temperature resistant alumina ceramic insulator is made from the following raw materials by weight percentage: 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 1.0 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 1.75 wt% zirconium oxide whiskers, and 91.5 wt% α-alumina aggregate. The mass ratio of α-alumina X: α-alumina Y: α-alumina Z is 66:25:9.

[0076] The difference between Comparative Example 1 and Example 1 is that the high-temperature resistant alumina ceramic insulator is composed of 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, and 95.25 wt% median diameter D. 50 It is made of 1.18 μm α-alumina X.

[0077] The difference between Comparative Example 2 and Example 1 is that the high-temperature resistant alumina ceramic insulator is composed of 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% silicon dioxide, and 94.25 wt% median diameter D. 50 It is made of 1.18 μm α-alumina X.

[0078] The difference between Comparative Example 3 and Example 1 is that the high-temperature resistant alumina ceramic insulator is composed of 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, and 93.75 wt% median diameter D. 50 It is made of 1.18 μm α-alumina X.

[0079] The difference between Comparative Example 4 and Example 1 is that the high-temperature resistant alumina ceramic insulator is composed of 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 1.75 wt% zirconium oxide whiskers, and 92 wt% median diameter D. 50 It is made of 1.18 μm α-alumina X.

[0080] The difference between Comparative Example 5 and Example 1 is that the high-temperature resistant alumina ceramic insulator is composed of 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystal form, and 92 wt% median diameter D. 50 It is made of 1.18 μm α-alumina X.

[0081] The difference between Comparative Example 6 and Example 1 is that the high-temperature resistant alumina ceramic insulator is composed of 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystal form, and 92 wt% median diameter D. 50 It is made of α-alumina Y with a thickness of 0.491 μm.

[0082] The difference between Comparative Example 7 and Example 1 is that the high-temperature resistant alumina ceramic insulator is made from the following raw materials in the following weight percentages: 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 2.5 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystals, and 90 wt% α-alumina aggregate. The mass ratio of α-alumina X: α-alumina Y: α-alumina Z is 66:25:9.

[0083] Performance testing: 1. The bulk density of the sintered sample was measured using a hydrostatic balance. Density (%) = Bulk density * 100 / Theoretical density. 2. Impact toughness was determined according to GB / T44304-2024 "Test Method for Fracture Resistance at Room Temperature of Fine Ceramics - Indentation (IF) Method". 3. Tensile strength was determined according to GB / T23805-2009 "Test Method for Tensile Strength of Fine Ceramics at Room Temperature". 4. Compressive strength was determined according to GB / T 4740-2024 "Test Method for Strength of Ceramic Materials".

[0084] Table 1: Test parameters of high-temperature resistant alumina ceramic insulators in Examples 1-12 and Comparative Examples 1-7

[0085] Example 1 356.57 2409.8 12.49 99.48 Example 2 338.81 2284.6 11.28 98.87 Example 3 329.10 2149.9 10.59 98.46 Example 4 333.33 2166.7 10.74 98.59 Example 5 323.04 2189.5 10.26 99.35 Example 6 340.72 2329.1 11.57 99.42 Example 7 361.96 2515.9 13.09 99.51 Example 8 367.52 2481.6 12.94 99.59 Example 9 378.56 2539.4 13.16 99.71 Example 10 370.01 2469.5 12.87 99.56 Example 11 334.91 2191.8 10.94 99.35 Example 12 323.37 2164.6 10.28 99.29 Comparative Example 1 197.87 1563.2 5.44 96.78 Comparative Example 2 223.35 1748.2 5.96 97.35 Comparative Example 3 236.63 1862.4 6.47 98.01 Comparative Example 4 295.31 1978.7 7.08 98.16 Comparative Example 5 321.71 2059.4 9.79 98.29 Comparative Example 6 331.01 2096.8 9.98 98.34 Comparative Example 7 356.57 2386.4 10.15 99.08

[0086] Combining Examples 1-4 and Comparative Examples 5-6 with Table 1, it can be seen that the high-temperature resistant alumina ceramic insulators prepared by the aggregate method of α-alumina in this invention have higher density and excellent mechanical properties and impact toughness. Specifically, the comparison between the groups in Examples 1-4 shows that the mass ratio of α-alumina X:α-alumina Y:α-alumina Z is 66:25:9, and the median diameter D of α-alumina X:α-alumina Y:α-alumina Z is... 50 With a ratio of X:Y:Z = 1.18:0.491:265 = 100:41.61:22.20, the prepared high-temperature resistant alumina ceramic insulator has the best density and superior mechanical properties and impact toughness.

[0087] As can be seen from Example 1 and Comparative Example 1, and Table 1, compared with the existing 95% alumina ceramic body, the high-temperature resistant alumina ceramic insulator prepared in this invention has high density, excellent mechanical properties and impact toughness, and can meet the performance requirements of UHV power transmission networks for insulators.

[0088] Based on Examples 1, 5-7, and Comparative Examples 1-3, and in conjunction with Table 1, it can be seen that a sintering aid system consisting of 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5 wt% lanthanum oxide, and 0.5 wt% silicon dioxide can significantly improve the density of high-temperature alumina ceramic insulators, thereby enhancing their mechanical properties and impact toughness, and meeting the performance requirements of ultra-high voltage power transmission networks for insulators.

[0089] Based on Examples 1, 8-9, and Comparative Example 7, and in conjunction with Table 1, it can be seen that the amount of lanthanum oxide added should be controlled at 0.5-2.0 wt%. Excessive addition will affect the overall mechanical properties and impact toughness, and will also increase production costs.

[0090] A sintering aid system consisting of 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 1.0 wt% lanthanum oxide, and 0.5 wt% silicon dioxide can significantly improve the density of high-temperature alumina ceramic insulators, thereby enhancing their mechanical properties and impact toughness, and meeting the performance requirements of ultra-high voltage power transmission networks for insulators.

[0091] Based on Examples 8, 11-12, and Comparative Example 4, and in conjunction with Table 1, it can be seen that, under the same amount of toughening composite filler added, the toughening composite filler composed of zinc oxide whiskers, zirconium oxide whiskers, and potassium titanate whiskers can further improve the mechanical properties and impact toughness of high-temperature alumina ceramic insulators, and can meet the performance requirements of UHV transmission networks for insulators.

[0092] In summary, the present invention has excellent wear resistance, compressive strength, tensile strength, thermal shock resistance, and good impact toughness, which can meet the performance requirements of UHV power transmission networks for insulators.

[0093] It should be noted that this specific embodiment is merely an explanation of the technical solution of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A high-temperature resistant alumina ceramic insulator, characterized in that: The high-temperature resistant alumina ceramic insulator is made from the following raw materials in the indicated mass percentages: 1-10% sintering aid, 0.5-5% toughening composite filler, and the balance alumina aggregate; the sintering aid is composed of at least one of zirconium oxide, rare earth oxides, calcium oxide, magnesium oxide, silicon dioxide, manganese dioxide, and titanium dioxide; the rare earth oxide is at least one of yttrium oxide, lanthanum oxide, samarium oxide, and cerium oxide; the toughening composite filler is one or more of alumina whiskers, zinc oxide whiskers, zirconium oxide whiskers, aluminum nitride whiskers, silicon nitride crystals, and potassium titanate whiskers. The alumina aggregate consists of a median diameter D 50 α-alumina with a diameter of X μm and a median diameter D 50 α-alumina with a diameter of Y μm and a median diameter D 50 The α-alumina with a size of Z μm is composed of a mass ratio of (60-68):(24-28):(8-12); wherein the ratio of X:Y:Z is 1:(0.4-0.42):(0.22-0.23); and X, Y and Z are 1.0-1.20, 0.40-0.50 and 0.22-0.27 respectively.

2. The high-temperature resistant alumina ceramic insulator according to claim 1, characterized in that: The alumina aggregate consists of a median diameter D 50 α-alumina with a diameter of X μm and a median diameter D 50 α-alumina with a diameter of Y μm and a median diameter D 50 The α-alumina with a size of Z μm is composed of a mass ratio of 66:25:

9.

3. The high-temperature resistant alumina ceramic insulator according to claim 1, characterized in that: The sintering aid is composed of zirconium oxide, calcium oxide, magnesium oxide, yttrium oxide, lanthanum oxide, and silicon dioxide; the mass ratio of zirconium oxide to calcium oxide, magnesium oxide, yttrium oxide, lanthanum oxide, and silicon dioxide is (4-10):1:1:1:(1-4):

1.

4. The high-temperature resistant alumina ceramic insulator according to claim 1, characterized in that: The toughening composite filler is composed of zinc oxide whiskers, zirconium oxide whiskers, and potassium titanate whiskers, with the mass ratio of zinc oxide whiskers to zirconium oxide whiskers and potassium titanate whiskers being (0.1-0.4):(1-2):(0.5-2).

5. A high-temperature resistant alumina ceramic insulator according to claim 1, characterized in that: The high-temperature resistant alumina ceramic insulator is made of 3-4 wt% zirconium oxide, 0.4-0.6 wt% calcium oxide, 0.4-0.6 wt% magnesium oxide, 0.4-0.6 wt% yttrium oxide, 0.4-2.0 wt% lanthanum oxide, 0.4-0.6 wt% silicon dioxide, 0.2-0.8 wt% zinc oxide whiskers, 1.0-3.0 wt% zirconium oxide whiskers, 0.2-0.8 wt% potassium titanate crystals, and the balance being alumina aggregate.

6. A high-temperature resistant alumina ceramic insulator according to claim 5, characterized in that: The high-temperature resistant alumina ceramic insulator is composed of 3.75% zirconium oxide, 0.5 wt% calcium oxide, 0.5 wt% magnesium oxide, 0.5 wt% yttrium oxide, 0.5-2.0 wt% lanthanum oxide, 0.5 wt% silicon dioxide, 0.25 wt% zinc oxide whiskers, 1.0 wt% zirconium oxide whiskers, 0.5 wt% potassium titanate crystal form, and 60.72 wt% median diameter D. 50 It is 1.0-1.20 μm α-alumina with a median diameter D of 23.0 wt%. 50 It has an α-alumina particle size of 0.40-0.50 μm and a median diameter D of 8.28 wt%. 50 It is made of α-alumina with a thickness of 0.22-0.27 μm.

7. A method for preparing a high-temperature resistant alumina ceramic insulator according to any one of claims 1-6, characterized in that: Includes the following steps: Step 1, Preparation of alumina aggregate: The median diameter D... 50 α-alumina with a diameter of 1.0-1.20 μm and a median diameter D 50 α-alumina with a diameter of 0.40-0.50 μm and a median diameter D 50 The α-alumina with a particle size of 0.22-0.27 μm can be obtained by mixing it evenly according to the formula; at the same time, the sintering aid is compounded: zirconium oxide, calcium oxide, magnesium oxide, yttrium oxide, lanthanum oxide and silicon dioxide can be mixed evenly according to the formula. Simultaneously, the toughening composite filler is prepared by mixing zinc oxide whiskers, zirconium oxide whiskers, and potassium titanate whiskers evenly according to the formula. Step 2: Place the sintering aid, toughening composite filler, and alumina aggregate prepared in Step 1 into a high-speed dispersion kettle, and disperse them at a high speed of 400-600 r / min for 4-6 h under nitrogen protection. After thorough mixing, the insulator ceramic material composition can be obtained. Step 3: The insulator porcelain material composition in Step 2 is mixed with polyvinyl alcohol binder at a mass ratio of 100:(6-8) and granulated. The resulting granules are sieved through a 40-80 mesh screen to obtain spherical insulator granules sieved through a 40-80 mesh screen. Step four: Place the insulator spherical granules prepared in step three into a molding die and obtain a rough blank through isostatic pressing. Step 5: Perform spark plasma sintering on the rough blank from Step 4 to obtain the finished high-temperature resistant alumina ceramic insulator.

8. The preparation method according to claim 7, characterized in that: In step five, the rough blank from step four is placed in a spark plasma sintering furnace. The vacuum degree is adjusted to ≤10Pa and the pressure to 6-9MPa. The temperature is first raised to 1020-1060℃ at a heating rate of 100-250℃ / min, then raised to 1550-1650℃ at a heating rate of 25-50℃ / min and held for 2-4 hours. The temperature is then adjusted to 1020-1060℃ at a cooling rate of 400-600℃ / h and held for 0.5-2 hours. Finally, the temperature is adjusted to 800-850℃ at a cooling rate of 400-600℃ / h. The furnace is then opened and the blank is allowed to cool naturally to room temperature. The blank is then demolded to obtain the finished high-temperature resistant alumina ceramic insulator.