Fuse ceramic tube and method of making same

Abstract

This invention belongs to the field of ceramic materials technology, specifically relating to ceramic fuse shells and their preparation method. The preparation method includes: ball milling a mixture of calcined α-alumina, borosilicate glass frit, γ-alumina, a composite grain bridging agent, a composite pore-sealing reinforcing agent, and deionized water; adjusting the pH to a neutral range; adding an aqueous solution containing polyvinyl alcohol and continuing mixing; sieving and spray drying to obtain granules; mixing with magnesium stearate and pressing into green bodies; placing the green bodies in a degreasing furnace; heating to different temperatures in stages under an air atmosphere and holding at those temperatures to complete degreasing; transferring the degreased green bodies to a sintering furnace; heating to a high temperature and holding at that temperature under a nitrogen protective atmosphere; and cooling in the furnace to obtain the finished ceramic shell. This invention, by introducing a composite grain bridging agent and a composite pore-sealing reinforcing agent, combined with staged degreasing and nitrogen atmosphere sintering, effectively improves the density, insulation performance, and bending strength of the shell, making it suitable for fuse applications.

Description

Technical Field

[0001] This invention belongs to the field of ceramic materials technology, specifically relating to ceramic tube shells for fuses and their preparation methods. Background Technology

[0002] The ceramic fuse shell is a key insulating structural component in fuse products, primarily used to support the fusible element and withstand thermal shock and electrical stress under high voltage and high current conditions. With the development of power systems towards higher voltage and miniaturization, higher requirements are placed on the comprehensive performance of the shell material, including high density, high insulation resistance, excellent flexural strength, and good thermal stability. Alumina ceramics have become the mainstream matrix material for manufacturing fuse shells due to their high mechanical strength, good insulation, high temperature resistance, and relatively low cost. However, conventional alumina ceramic preparation processes have significant shortcomings: sintering temperatures typically need to exceed 1500 degrees Celsius to achieve high density, resulting in high energy consumption and demanding equipment requirements; to lower the sintering temperature, glass frit or other sintering aids are often added, but excessive addition can lead to a decrease in insulation performance; furthermore, abnormal grain growth is prone to occur during sintering, forming microcracks or pores, weakening the mechanical strength of the shell. Simultaneously, improper heating rates or inadequate atmosphere control during the green body debinding stage can easily lead to defects such as cracking and delamination. Therefore, how to obtain dense, high-strength, highly insulating and dimensionally stable alumina-based ceramic tube shells at lower sintering temperatures has become a technical problem that urgently needs to be solved in this field.

[0003] To address the aforementioned issues, researchers have attempted to incorporate various additives into the alumina matrix to improve sintering behavior and microstructure. For example, adding magnesium oxide or zirconium oxide can inhibit grain growth, but the effect of a single additive is limited and may introduce uneven distribution of the second phase. Using low-melting-point borosilicate glass frit can effectively reduce the sintering temperature, but excessive presence of the glass phase can form a continuous network, reducing the high-temperature volume resistivity of the material, posing a breakdown risk, especially in high-voltage fuse applications. In recent years, some literature has reported utilizing the weak interfacial bonding characteristics between monazite-type lanthanum phosphate and alumina to achieve crack deflection and bridging, improving the fracture toughness of ceramics; however, when lanthanum phosphate is directly combined with alumina, its dispersibility is poor, and the interfacial control effect is not significant. On the other hand, residual openings in the sintered ceramic body can seriously affect insulation performance. Existing sealing processes mostly employ impregnation with organic resin or secondary glazing, which not only increases the number of steps but also makes the organic sealing agent prone to volatilization and failure at high temperatures. The application of cerium-doped yttrium aluminum garnet and other functional phases in alumina-based ceramics is limited, especially since controlling the valence state of cerium ions requires a specific atmosphere and involves complex processes. Therefore, current technologies lack an integrated solution that can simultaneously achieve grain refinement control, pore sealing and strengthening, and low-temperature densification. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a ceramic tube shell for a fuse and a method for preparing the same.

[0005] A first aspect of the present invention provides a method for preparing a ceramic housing for a fuse, comprising the steps of:

[0006] S1. By weight, 70-85 parts of calcined α-alumina, 5-12 parts of borosilicate glass, 3-8 parts of γ-alumina, 2-5 parts of composite grain bridging regulator, 1-4 parts of composite sealing and reinforcing agent, and 65-80 parts of deionized water are placed in a ball mill and ball-milled. The pH is adjusted to 6-8, and an aqueous solution containing 1.5-3.0 parts of polyvinyl alcohol is added. The mixture is continued to be mixed and sieved to obtain a mixed slurry. The mixed slurry is spray-dried to obtain granules. The granules are mixed with 0.3-0.8 parts of magnesium stearate in a mixer to obtain a mixture. The mixture is filled into a mold and pressed to obtain a green body.

[0007] S2. Place the green billet in a degreasing furnace and heat it to 175-185℃ in an air atmosphere and hold it there; continue to heat it to 295-305℃ and hold it there; continue to heat it to 495-505℃ and hold it there; finally, heat it to 595-605℃ and hold it there to obtain the degreased green billet; transfer the degreased green billet to a sintering furnace, introduce nitrogen gas, heat it to 1350-1480℃ and hold it there; let it cool naturally to room temperature with the furnace.

[0008] In this invention, the overall fabrication of the ceramic shell for the fuse involves a coupled process of multiphase synergistic liquid-phase assisted densification sintering and micro-interface control. In the slurry preparation stage: calcined α-alumina, borosilicate glass frit, γ-alumina, a composite grain bridging agent, and a composite sealing and reinforcing agent are wet-milled in deionized water using alumina balls as the grinding medium. The borosilicate glass frit contains silicon dioxide, boron trioxide, aluminum oxide, calcium oxide, magnesium oxide, and sodium oxide, maintaining a stable amorphous silicon-oxygen / boron-oxygen network structure at room temperature. The slurry pH is adjusted to a neutral range to maintain electrostatic repulsion stability between particles, avoiding slight hydrolysis of strontium zirconate under slightly acidic conditions and surface corrosion of lanthanum phosphate. In the later stages of the ball milling process, a pre-prepared aqueous solution of polyvinyl alcohol is added for further mixing. The long-chain polymers of polyvinyl alcohol bind to the surface of inorganic particles in the aqueous phase through hydrogen bonds and van der Waals forces, forming a coating layer. Spray drying and mixing stage: After ball milling, the slurry is filtered through a sieve, and the filtrate is sent to a spray drying tower for granulation. The slurry is atomized into fine droplets, and the water evaporates rapidly. The inorganic particles coated with polyvinyl alcohol agglomerate and shrink to form spherical particles. The sprayed particles are then dry-mixed with magnesium stearate in a mixer, resulting in a uniform layered molecular structure of magnesium stearate adhering to the outer surface of the particles. Dry pressing stage: The mixture is filled into a mold and uniaxially pressurized for molding. During pressurization, interlayer slippage occurs between the layered molecules of magnesium stearate, reducing friction between particles and between particles and the inner wall of the mold, promoting particle rearrangement to achieve a higher green density and obtaining a tube-shaped green body. Degreasing stage: The green body is placed in a degreasing furnace and subjected to four-stage stepped heating and holding in an air atmosphere. Polyvinyl alcohol undergoes chain segment relaxation and water evaporation, a first-stage dehydration reaction to generate conjugated polyene structures, main chain breakage and decomposition into low-molecular-weight hydrocarbons, and oxidation and burn-off of residual carbon. Magnesium stearate undergoes a multi-stage process involving the loss of crystal water, decomposition of long-chain fatty acids, and oxidation to form magnesium oxide. An air atmosphere ensures complete oxidation and combustion of the organic binder, with decomposition products escaping as volatile gases, forming a relatively uniform network of interconnected venting pores within the green body. Sintering stage: The degreased green body is transferred to a sealed container with a sagger lid or a closed high-temperature atmosphere sintering furnace. High-purity nitrogen is introduced to maintain a slightly positive pressure in the furnace while the temperature is raised and held for sintering. The choice of nitrogen atmosphere is based on two considerations: firstly, to prevent oxygen in the air from re-oxidizing the solidified trivalent cerium ions in the composite sealing and reinforcing agent to tetravalent cerium ions at high temperatures, thus protecting the electron-trapping active centers of the cerium trivalent / tetravalent valence pair; secondly, nitrogen, as an inert atmosphere, does not react with the matrix oxide. During sintering, the following parallel reactions occur: γ-alumina transforms into α-alumina, co-densifying with calcined α-alumina; borosilicate glass forms a liquid phase, promoting particle rearrangement and mass migration. Lanthanum phosphate forms a weak interfacial phase at grain boundaries, deflecting and bridging cracks and improving toughness. Strontium zirconate pins grain boundaries, inhibiting abnormal grain growth. Magnesium aluminum spinel diffuses along grain boundaries, sealing residual porosity.In cerium-doped yttrium aluminum garnet, trivalent cerium ions act as electron traps, capturing free electrons, blocking electron avalanche propagation, and enhancing arc resistance. Upon cooling, the glass phase solidifies, resulting in a dense, thermally shock resistant, and arc-resistant ceramic tube shell.

[0009] According to a preferred embodiment of the present invention, in step S1, the composition of the borosilicate glass material, based on oxides, includes: 55-65 wt% silicon dioxide, 10-18 wt% boron trioxide, 8-15 wt% aluminum trioxide, 5-10 wt% calcium oxide, 3-7 wt% magnesium oxide, and 1-3 wt% sodium oxide.

[0010] According to a preferred embodiment of the present invention, in step S2, the holding time for heating to 175-185℃ is 1-2 hours; the holding time for heating to 295-305℃ is 1-2 hours; the holding time for heating to 495-505℃ is 1-2 hours; the holding time for heating to 595-605℃ is 2-4 hours; and the holding time for heating to 1350-1480℃ is 2-5 hours.

[0011] According to a preferred embodiment of the present invention, the preparation method of the composite grain bridging regulator includes: A1, calcining lanthanum oxide in a muffle furnace at 795-805°C (by weight) to obtain calcined lanthanum oxide; adding 7.5-9.0 parts of calcined lanthanum oxide and 6.1-7.3 parts of diammonium hydrogen phosphate to 25-40 parts of anhydrous ethanol, ball milling to obtain slurry A; drying slurry A at 78-82°C to obtain dried product A; adding 6.8-8.2 parts of strontium carbonate and 5.7-6.8 parts of zirconium dioxide... Add 25-40 parts of anhydrous ethanol and ball mill to obtain slurry B; dry slurry B at 78-82℃ to obtain dried product B; transfer dried product A to a platinum crucible and heat to 395-405℃ and hold; continue heating to 595-605℃ and hold; continue heating to 1195-1205℃ and hold to obtain lanthanum phosphate powder; put dried product B into a platinum crucible and heat to 1395-1405℃ and hold to obtain strontium zirconate powder; grind the lanthanum phosphate powder and strontium zirconate powder separately, sieve, and mix.

[0012] In this invention, the synthesis of the composite grain bridging regulator involves two independent solid-phase reaction routes to obtain lanthanum phosphate powder and strontium zirconate powder, respectively. The synthesis mechanism of lanthanum phosphate powder is as follows: lanthanum oxide is calcined to remove surface adsorbed water and carbonate impurities, then ball-milled with diammonium hydrogen phosphate in anhydrous ethanol. Anhydrous ethanol serves as the dispersion medium to avoid inhomogeneity caused by partial dissolution and re-precipitation of diammonium hydrogen phosphate in water. The mixed powder is dried and then placed in a platinum crucible for multi-stage programmed temperature calcination. The platinum crucible is chosen to prevent the phosphate precursor from corroding the alumina crucible at high temperatures, generating an aluminum phosphate impurity phase. At lower temperatures, diammonium hydrogen phosphate releases ammonia and water vapor sequentially through the ammonium dihydrogen phosphate intermediate, transforming into metaphosphoric acid and polyphosphoric acid active intermediates. At intermediate temperatures, the ammonium groups completely escape, and the metaphosphoric acid / polyphosphoric acid reacts with the surface of the lanthanum oxide particles to generate the intermediate product lanthanum tripolyphosphate. At high temperatures, the intermediate phase undergoes further crystal reconstruction and atomic ordering, ultimately transforming into lanthanum phosphate powder with a monazite-type crystal structure. Synthesis mechanism of strontium zirconate powder: Strontium carbonate and zirconium dioxide are ball-milled and dried in anhydrous ethanol, then placed in an unstabilized pure monoclinic zirconium dioxide crucible or a platinum crucible (partially stabilized zirconium oxide crucibles containing yttrium oxide stabilizers are avoided to prevent the introduction of impurities; simultaneously, since strontium oxide reacts with alumina at high temperatures to form strontium aluminate byproducts, alumina crucibles are not used) for high-temperature calcination. At this temperature, the decomposition of strontium carbonate to release carbon dioxide and the consumption of free strontium oxide by zirconium dioxide to drive the reaction equilibrium are simultaneously coupled. Strontium oxide migrates unidirectionally through the interface to the surface of zirconium dioxide particles to nucleate and form a strontium zirconate layer, which gradually thickens, eventually transforming into perovskite-type crystal structure strontium zirconate powder. Lanthanum phosphate powder and strontium zirconate powder are separately ground, sieved, and mechanically mixed in proportion to obtain composite grain bridging regulator powder.

[0013] According to a preferred embodiment of the present invention, in step A1, the calcination time at 795-805°C is 2-4 hours.

[0014] According to a preferred embodiment of the present invention, in step A2, the holding time for heating to 395-405℃ is 2-4 hours; the holding time for heating to 595-605℃ is 2-4 hours; the holding time for heating to 1195-1205℃ is 4-6 hours; and the holding time for heating to 1395-1405℃ is 6-8 hours.

[0015] According to a preferred embodiment of the present invention, the preparation method of the composite sealing and reinforcing agent includes: B1, drying basic magnesium carbonate at 108-112°C to obtain dried basic magnesium carbonate; calcining yttrium oxide in a muffle furnace to 895-905°C to obtain calcined yttrium oxide; calcining cerium dioxide in a muffle furnace to 595-605°C to obtain calcined cerium dioxide; adding 4.5-5.4 parts of dried basic magnesium carbonate and 7.2-8.7 parts of aluminum hydroxide to 25-40 parts of deionized water, ball milling to obtain slurry C; drying slurry C at 58-62°C to obtain dried product C; and adding 4.5-5.5 parts of calcined yttrium oxide, 0.21-0.26 parts of calcined cerium dioxide, and 5.3- 6.5 parts aluminum hydroxide are added to 25-40 parts deionized water and ball-milled to obtain slurry D; slurry D is dried at 58-62℃ to obtain dried product D; B2. Dried product C is placed in a corundum crucible and heated to 595-605℃ in air atmosphere and held; the temperature is further increased to 1495-1505℃ and held to obtain magnesium aluminum spinel powder; dried product D is placed in a corundum crucible and heated to 598-602℃ in air atmosphere and held; after cooling, it is transferred to a tube furnace, a mixture of hydrogen and nitrogen is introduced, and the temperature is increased to 1598-1602℃ and held; the temperature is decreased to 298-302℃, and the atmosphere is switched to nitrogen to obtain cerium-doped yttrium aluminum garnet powder; the magnesium aluminum spinel powder and the cerium-doped yttrium aluminum garnet powder are pulverized, sieved, and mixed separately.

[0016] In this invention, the synthesis of the composite sealing and reinforcing agent involves two independent reaction routes, yielding magnesium aluminum spinel powder and cerium-doped yttrium aluminum garnet powder, respectively. Raw material pretreatment: Basic magnesium carbonate is dried in an oven to remove free water molecules adsorbed in the interstitial spaces to ensure accurate stoichiometry. Yttrium oxide is calcined in a muffle furnace to remove surface-adsorbed water and surface carbonates. Cerium dioxide is calcined in a muffle furnace to remove surface-adsorbed moisture and carbonates (calcination temperature is controlled to avoid excessive cerium dioxide grain growth and reduced reactivity). The synthesis mechanism of the magnesium aluminum spinel powder: Dried basic magnesium carbonate and aluminum hydroxide are ball-milled and mixed in deionized water according to the aluminum-magnesium stoichiometry. After drying, the mixture is placed in a corundum crucible for multi-stage heating and calcination in an air atmosphere. At lower temperatures, basic magnesium carbonate decomposes, releasing carbon dioxide and water vapor and generating active magnesium oxide in situ; simultaneously, aluminum hydroxide undergoes dehydration through the boehmite mesophase to form a γ-alumina transition phase with a high specific surface area. During the high-temperature stage, magnesium oxide and γ-alumina undergo a solid-phase diffusion reaction, with magnesium and aluminum ions diffusing across phase boundaries to gradually build a face-centered cubic oxygen ion framework, ultimately crystallizing into magnesium aluminum spinel powder with a spinel-type crystal structure. The synthesis mechanism of cerium-doped yttrium aluminum garnet powder is as follows: Calcinated yttrium oxide, calcined cerium dioxide, and aluminum hydroxide are ball-milled and mixed in deionized water according to the stoichiometric ratio of total yttrium and cerium to aluminum and the doping ratio of cerium to total yttrium and cerium. After drying, the mixture is placed in a corundum crucible and heated and held in air to dehydrate the aluminum hydroxide and form a γ-alumina transition phase. After cooling, it is transferred to a tube furnace, where a hydrogen / nitrogen reducing atmosphere is introduced to replace the furnace air before calcination. Under this reducing atmosphere and high temperature conditions, hydrogen partially reduces cerium dioxide to cerium trioxide and reduces tetravalent cerium ions to trivalent cerium ions. Since the ionic radius of trivalent cerium ions is close to that of trivalent yttrium ions, they can stably dissolve and enter the yttrium ion sites of the yttrium aluminum garnet lattice. At this point, yttrium oxide, α-alumina (derived from the phase transformation of γ-alumina), and cerium trioxide are arranged according to the general formula of garnet structure to form a cerium-doped yttrium aluminum garnet single phase. During the cooling stage, the reducing atmosphere is maintained until the furnace temperature drops to a lower level, after which it is switched to a nitrogen atmosphere. The purpose is to prevent the trivalent cerium ions that have already dissolved during cooling from being re-oxidized to tetravalent cerium ions by oxygen in the air and precipitating out from outside the lattice. Magnesium aluminum spinel powder and cerium-doped yttrium aluminum garnet powder are separately pulverized, sieved, and mechanically mixed in a specific ratio to obtain a composite sealing and reinforcing agent powder.

[0017] According to a preferred embodiment of the present invention, in step B1, the calcination time at 895-905°C is 2-4 hours; the calcination time at 595-605°C is 2-4 hours.

[0018] According to a preferred embodiment of the present invention, in step B2, the holding time for heating to 595-605℃ is 3-5 hours; the holding time for heating to 1495-1505℃ is 6-8 hours; the holding time for heating to 598-602℃ is 3-5 hours; and the holding time for heating to 1598-1602℃ is 6-8 hours.

[0019] In a second aspect, the present invention provides a fuse ceramic housing prepared according to the method for preparing the fuse ceramic housing described above.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The ceramic body preparation process of the present invention constructs a highly dense and structurally stable basic network through the synergistic effect of multiple components. The borosilicate glass material introduced into the formulation system softens and forms a uniform liquid phase during the high-temperature heating stage. The silica, boron trioxide, aluminum trioxide, calcium oxide, magnesium oxide and sodium oxide contained in the glass material jointly regulate the viscosity and wettability of the liquid phase, penetrate and fill the tiny gaps between solid particles, and promote material transfer and overall densification. In the slurry preparation stage, deionized water is added as a dispersion medium and the pH of the system is controlled to a specified range. Then, a completely dissolved polyvinyl alcohol aqueous solution is added so that the organic polymer chains are coated on the surface of the inorganic powder, providing support for subsequent spray drying granulation. Magnesium stearate added before molding is used as a solid lubricant to reduce the frictional resistance between powders and the adhesion force between the material and the inner wall of the mold during the mold pressing stage, so that the density of the pressed green body is uniform. After degreasing by slow heating in multiple steps, the internal organic matter is completely oxidized and discharged without cracking.

[0022] (2) The composite grain bridging regulator designed in this invention plays a role in limiting abnormal crystal growth at high temperatures and enhancing the toughness of the matrix. The preparation process of this composite grain bridging regulator involves dispersing pre-calcined and activated lanthanum oxide and diammonium hydrogen phosphate in anhydrous ethanol, grinding and drying them, and then placing them in a platinum crucible for multi-stage isothermal calcination to obtain lanthanum phosphate powder. At the same time, strontium carbonate and zirconium dioxide are mixed in anhydrous ethanol and calcined in a platinum crucible at a higher temperature to generate strontium zirconate powder. After grinding and mixing the above two powders, they are added to the main material. During high-temperature liquid-phase sintering, lanthanum phosphate segregates at the main grain boundaries, forming a weak interface layer that can deflect the propagation of microcracks and improve thermal shock resistance; strontium zirconate, with its high-temperature stability and electrical insulation, forms pinning nodes in the microstructure, consolidating the electrical insulation reliability of the ceramic structure.

[0023] (3) The composite sealing reinforcement introduced in this invention further improves the sealing pores and electrical properties. In the preparation process of this composite sealing reinforcement, dried basic magnesium carbonate and aluminum hydroxide are used as precursors and calcined at high temperature in a corundum crucible and air atmosphere to obtain magnesium aluminum spinel powder; calcined yttrium oxide, cerium dioxide and aluminum hydroxide are mixed, pre-calcined in air atmosphere, transferred to a tube furnace and treated at high temperature in a mixed atmosphere of hydrogen and nitrogen, and switched to nitrogen atmosphere during cooling to obtain cerium-doped yttrium aluminum garnet powder. In the sintering stage of the finished product, magnesium aluminum spinel migrates along the grain boundaries and fills the micropores remaining after sintering to achieve deep densification; the trivalent cerium ions retained in the cerium-doped yttrium aluminum garnet powder can capture free electrons under the action of an electric field, blocking the electron avalanche propagation path during arc discharge, thereby improving the arc impact resistance and service life of the ceramic tube shell. Detailed Implementation

[0024] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0025] Example 1

[0026] This embodiment provides a method for preparing a ceramic casing for a fuse, the steps of which include:

[0027] S1: Place 77.5g of calcined α-alumina, 8.5g of borosilicate glass material (composition: 60wt% silicon dioxide, 14wt% boron trioxide, 11.5wt% aluminum trioxide, 7.5wt% calcium oxide, 5wt% magnesium oxide, 2wt% sodium oxide), 5.5g of γ-alumina, 3.5g of composite grain bridging regulator, 2.5g of composite sealing and reinforcing agent, and 60g of deionized water in a planetary ball mill. Use alumina balls as the grinding medium, adjust the pH of the slurry to 7 with dilute ammonia, and mill at 300 rpm for 12 hours. Before the last 2 hours of the total milling time, pre-prepare 2.25g of polyvinyl alcohol (PVA-1788) to form a 1 A 0wt% aqueous solution was added to the slurry and mixed further. The resulting slurry was filtered through an 180-mesh sieve to obtain a mixed slurry. The mixed slurry was transferred to a spray drying tower for granulation. The inlet air temperature was 250℃, the outlet air temperature was 105℃, and the atomizer speed was 10000rpm, resulting in spherical agglomerated particles with an average particle size of 50μm. The spherical agglomerated particles were dry-mixed with 0.55g of magnesium stearate powder in a mixer for 45min at a mixing speed of 35rpm, so that the magnesium stearate was uniformly attached to the outer surface of the spherical agglomerated particles. The mixture was filled into a mold and subjected to uniaxial pressure of 150MPa for 10s to form a green body.

[0028] S2: The green blank is placed in a degreasing furnace and heated from room temperature to 180℃ at a heating rate of 1℃ / min under air atmosphere and held for 1.5h; the temperature is then increased to 300℃ at 1℃ / min and held for 1.5h; the temperature is then increased to 500℃ at 1℃ / min and held for 1.5h; finally, the temperature is increased to 600℃ at 1.5℃ / min and held for 3h to obtain the degreased green blank; the degreased green blank is transferred to a sealed container with a sagger lid, and a high-purity N2 protective atmosphere is introduced, and the temperature is increased to 1415℃ at a heating rate of 6℃ / min and held for 3.5h for sintering; after sintering, the green blank is naturally cooled to room temperature under N2 atmosphere to obtain the finished ceramic tube shell of the fuse.

[0029] Preparation of composite grain bridging regulators:

[0030] A1: Lanthanum oxide was calcined in a muffle furnace at 5℃ / min to 800℃ for 3 hours to obtain calcined lanthanum oxide; 8.25g of calcined lanthanum oxide and 6.7g of diammonium hydrogen phosphate were added to 32.5g of anhydrous ethanol and placed in a nylon ball mill jar with zirconium oxide balls as the grinding medium, and ball milled at 300rpm for 4 hours to obtain slurry A; slurry A was dried in an oven at 80℃ for 12 hours to obtain dried product A; 7.5g of strontium carbonate and 6.25g of zirconium dioxide were added to 32.5g of anhydrous ethanol and ball milled at 300rpm for 6 hours to obtain slurry B; slurry B was dried in an oven at 80℃ for 12 hours to obtain dried product B.

[0031] A2: Transfer dried material A to a platinum crucible, heat to 400℃ at 5℃ / min and hold for 3h; continue heating to 600℃ at 5℃ / min and hold for 3h; continue heating to 1200℃ at 5℃ / min and hold for 5h to obtain lanthanum phosphate powder; put dried material B into a platinum crucible, heat to 1400℃ at 5℃ / min and hold for 7h to obtain strontium zirconate powder; grind the lanthanum phosphate powder and strontium zirconate powder separately and pass them through a 200-mesh sieve, then mechanically mix them at a mass ratio of 1:1 to obtain a composite grain bridging regulator.

[0032] Preparation of composite sealing and reinforcing agents:

[0033] B1: Basic magnesium carbonate was dried in an oven at 110℃ for 2 hours to obtain dried basic magnesium carbonate; yttrium oxide was calcined in a muffle furnace at a temperature of 5℃ / min to 900℃ for 3 hours to obtain calcined yttrium oxide; cerium dioxide was calcined in a muffle furnace at a temperature of 5℃ / min to 600℃ for 3 hours to obtain calcined cerium dioxide; 4.95g of dried basic magnesium carbonate and 7.95g of aluminum hydroxide were added to 32.5g of deionized water and placed in a nylon container. Zirconia balls were used as the grinding medium in a ball mill jar and the mixture was ball-milled at 350 rpm for 4 hours to obtain slurry C. Slurry C was then dried by rotary evaporation in a water bath at 60°C to obtain dried product C. 5.0 g of calcined yttrium oxide, 0.235 g of calcined cerium dioxide, and 5.9 g of aluminum hydroxide were added to 32.5 g of deionized water and ball-milled at 350 rpm for 4 hours to obtain slurry D. Slurry D was then dried by rotary evaporation in a water bath at 60°C to obtain dried product D.

[0034] B2: Place dried material C in an alumina crucible and heat it to 600℃ at 3℃ / min in air atmosphere and hold for 4h; continue heating to 1500℃ at 5℃ / min and hold for 7h to obtain magnesium aluminum spinel powder; place dried material D in an alumina crucible and heat it to 600℃ at 3℃ / min in air atmosphere and hold for 4h; after cooling, transfer it to a tube furnace and introduce a 5% hydrogen / 95% nitrogen reducing atmosphere mixture at a flow rate of 300mL / min. After replacing the air for 30min, heat it to 1600℃ at 5℃ / min and hold for 7h; maintain the reducing atmosphere during cooling until the furnace temperature drops to 300℃, then switch to N2 atmosphere to obtain cerium-doped yttrium aluminum garnet powder; pulverize the magnesium aluminum spinel powder and cerium-doped yttrium aluminum garnet powder separately and pass them through a 325-mesh sieve. Place them in a mixer at a mass ratio of 2:1 and dry mix for 30min to obtain a composite sealing and reinforcing agent.

[0035] Example 2

[0036] The difference between this embodiment and Embodiment 1 is that this embodiment provides a method for preparing the ceramic shell of the fuse, the steps of which include:

[0037] S1: 70g of calcined α-alumina, 5g of borosilicate glass material (composition: 55wt% silica, 10wt% boron trioxide, 8wt% aluminum trioxide, 5wt% calcium oxide, 3wt% magnesium oxide, 1wt% sodium oxide), 3g of γ-alumina, 2g of composite grain bridging regulator, 1g of composite sealing agent, and 55g of deionized water were placed in a planetary ball mill. Alumina balls were used as the grinding medium, and the pH was adjusted to 6 with dilute ammonia. The ball milling speed was 280 rpm, and the milling time was 8 hours. Before the last 2 hours of the total milling time, 1.5g of polyvinyl alcohol was prepared as a 10wt% aqueous solution and added to the slurry for further mixing. The mixture was passed through a 150-mesh sieve to obtain a mixed slurry. Spray drying was performed at an inlet temperature of 220℃, an outlet temperature of 90℃, and an atomizer speed of 8000 rpm to obtain spherical particles with an average particle size of 30μm. These particles were then mixed with 0.3g of magnesium stearate (20 rpm, 30 min). Molding is performed by applying 100MPa uniaxial pressure and holding it for 5 seconds.

[0038] S2: Place the green billet in a degreasing furnace and heat it to 175℃ at a rate of 0.5℃ / min under air atmosphere, holding for 1 hour; then heat it to 295℃ at a rate of 0.5℃ / min, holding for 1 hour; then heat it to 495℃ at a rate of 0.5℃ / min, holding for 1 hour; finally, heat it to 595℃ at a rate of 1℃ / min, holding for 2 hours. Transfer it to a sealed container, purge with high-purity N2, heat it to 1350℃ at a rate of 3℃ / min, holding for 2 hours, and then cool it in the furnace to obtain the finished product.

[0039] Preparation of composite grain bridging regulators:

[0040] A1: Lanthanum oxide was calcined in a muffle furnace at 795℃ for 2 hours at a rate of 5℃ / min to obtain calcined lanthanum oxide. 7.5g of the calcined lanthanum oxide and 6.1g of diammonium hydrogen phosphate were added to 25g of anhydrous ethanol and milled in a nylon ball mill jar using zirconium oxide balls as the grinding medium at 300 rpm for 4 hours to obtain slurry A. Slurry A was dried in an oven at 80℃ for 12 hours to obtain dried product A. Separately, 6.8g of strontium carbonate and 5.7g of zirconium dioxide were added to 25g of anhydrous ethanol and milled at 300 rpm for 6 hours to obtain slurry B. Slurry B was dried in an oven at 80℃ for 12 hours to obtain dried product B.

[0041] A2: Transfer dried material A to a platinum crucible, heat to 395℃ at 5℃ / min and hold for 2 hours; continue heating to 595℃ at 5℃ / min and hold for 2 hours; continue heating to 1195℃ at 5℃ / min and hold for 4 hours to obtain lanthanum phosphate powder. Place dried material B into a platinum crucible, heat to 1395℃ at 5℃ / min and hold for 6 hours to obtain strontium zirconate powder. Grind the lanthanum phosphate powder and strontium zirconate powder separately and pass them through a 200-mesh sieve. Mechanically mix them at a mass ratio of 1:1 to obtain a composite grain bridging agent.

[0042] Preparation of composite sealing and reinforcing agents:

[0043] B1: Basic magnesium carbonate was dried in an oven at 110℃ for 2 hours to obtain dried basic magnesium carbonate. Yttrium oxide was calcined in a muffle furnace at a temperature of 5℃ / min to 895℃ for 2 hours to obtain calcined yttrium oxide. Cerium dioxide was calcined in a muffle furnace at a temperature of 5℃ / min to 595℃ for 2 hours to obtain calcined cerium dioxide. 4.5g of dried basic magnesium carbonate and 7.2g of aluminum hydroxide were added to 25g of deionized water and placed in a nylon ball mill jar with zirconia balls as the grinding medium. The mixture was ball-milled at 350rpm for 4 hours to obtain slurry C. Slurry C was then dried by rotary evaporation in a water bath at 60℃ to obtain dried product C. Take 4.5g of calcined yttrium oxide, 0.21g of calcined cerium dioxide and 5.3g of aluminum hydroxide and add them to 25g of deionized water. Ball mill at 350rpm for 4h to obtain slurry D. Dry slurry D by rotary evaporation in a water bath at 60℃ to obtain dried product D.

[0044] B2: Dry material C was placed in an alumina crucible and heated to 595℃ at 3℃ / min in air atmosphere, holding for 3 hours; then heated to 1495℃ at 5℃ / min and held for 6 hours to obtain magnesium aluminum spinel powder. Dry material D was placed in an alumina crucible and heated to 598℃ at 3℃ / min in air atmosphere, holding for 3 hours; after cooling, it was transferred to a tube furnace, and a 5% H2 / 95% N2 mixture was introduced at a flow rate of 200 mL / min to replace the air for 30 minutes. Then, the temperature was increased to 1598℃ at 5℃ / min and held for 6 hours; during cooling, a reducing atmosphere was maintained until the furnace temperature dropped to 298℃, then switched to an N2 atmosphere to obtain cerium-doped yttrium aluminum garnet powder. The magnesium aluminum spinel powder and cerium-doped yttrium aluminum garnet powder were separately pulverized and passed through a 325-mesh sieve, then dry-mixed at a mass ratio of 2:1 for 30 minutes to obtain a composite sealing and reinforcing agent.

[0045] Example 3

[0046] The difference between this embodiment and Embodiment 1 is that this embodiment provides a method for preparing the ceramic shell of the fuse, the steps of which include:

[0047] S1: Take 85g of calcined α-alumina, 12g of borosilicate glass material (composition: 65wt% silica, 18wt% boron trioxide, 15wt% aluminum trioxide, 10wt% calcium oxide, 7wt% magnesium oxide, 3wt% sodium oxide), 8g of γ-alumina, 5g of composite grain bridging regulator, 4g of composite pore-sealing enhancer, and 70g of deionized water. Ball mill the mixture, adjusting the pH to 8, at 350 rpm for 16 hours. Add 3.0g of a 10wt% aqueous solution of polyvinyl alcohol before the last 3 hours. Pass the mixture through a 200-mesh sieve and spray dry (inlet air 280℃, outlet air 120℃, 12000 rpm) to obtain particles with an average particle size of 80μm. Mix with 0.8g of magnesium stearate (50 rpm, 60 min). Mold at 200MPa for 15 seconds.

[0048] S2: Degreasing: Hold at 2℃ / min to 185℃ for 2 hours under air, then at 1.5℃ / min to 305℃ for 2 hours, then at 1.5℃ / min to 505℃ for 2 hours, and finally at 2℃ / min to 605℃ for 4 hours. Sintering: Hold at 10℃ / min to 1480℃ for 5 hours under high-purity N2, then cool with the furnace to obtain the finished product.

[0049] Preparation of composite grain bridging regulators:

[0050] A1: Lanthanum oxide was calcined in a muffle furnace at 805℃ for 4 hours at a rate of 5℃ / min to obtain calcined lanthanum oxide. 9.0 g of the calcined lanthanum oxide and 7.3 g of diammonium hydrogen phosphate were added to 40 g of anhydrous ethanol and ball-milled at 300 rpm for 4 hours. Slurry A was dried at 80℃ for 12 hours. 8.2 g of strontium carbonate and 6.8 g of zirconium dioxide were added to 40 g of anhydrous ethanol and ball-milled at 300 rpm for 6 hours. Slurry B was dried at 80℃ for 12 hours.

[0051] A2: Dried product A was heated in a platinum crucible at a rate of 5℃ / min to 405℃ and held for 4 hours, then to 605℃ and held for 4 hours, and finally to 1205℃ and held for 6 hours to obtain lanthanum phosphate powder. Dried product B was heated in a platinum crucible at a rate of 5℃ / min to 1405℃ and held for 8 hours to obtain strontium zirconate powder. Both were ground through a 200-mesh sieve and mixed in a 1:1 ratio.

[0052] Preparation of composite sealing and reinforcing agents:

[0053] B1: Basic magnesium carbonate was dried at 110℃ for 2 hours. Yttrium oxide was calcined at 905℃ for 4 hours with a heating rate of 5℃ / min, and cerium dioxide was calcined at 605℃ for 4 hours with a heating rate of 5℃ / min. 5.4g of dried basic magnesium carbonate and 8.7g of aluminum hydroxide were added to 40g of deionized water and ball-milled at 350rpm for 4 hours. Slurry C was then dried by rotary evaporation at 60℃. 5.5g of calcined yttrium oxide, 0.26g of calcined cerium dioxide, and 6.5g of aluminum hydroxide were added to 40g of deionized water and ball-milled at 350rpm for 4 hours. Slurry D was then dried by rotary evaporation at 60℃.

[0054] B2: Dried material C was heated to 605℃ in air at a rate of 3℃ / min and held for 5 hours, then heated to 1505℃ at a rate of 5℃ / min and held for 8 hours to obtain magnesium aluminum spinel powder. Dried material D was heated to 602℃ in air at a rate of 3℃ / min and held for 5 hours. After cooling, it was passed through a tube furnace with 5% H2 / 95% N2 (400 mL / min) and heated to 1602℃ at a rate of 5℃ / min and held for 8 hours. It was then cooled to 302℃ and N2 was switched to obtain cerium-doped yttrium aluminum garnet powder. The powder was pulverized through a 325-mesh sieve and mixed in a 2:1 ratio.

[0055] Comparative Example 1

[0056] The difference between this comparative example and Example 1 is that no composite grain bridging regulator is added in S1, the amount of calcined α-alumina is adjusted to 81g, and the remaining components and process parameters are the same as in Example 1.

[0057] Comparative Example 2

[0058] The difference between this comparative example and Example 1 is that no composite sealing agent is added in S1, the amount of calcined α-alumina is adjusted to 80g, and the remaining components and process parameters are the same as in Example 1.

[0059] Comparative Example 3

[0060] The difference between this comparative example and Example 1 is that in S1, only 83g of calcined α-alumina and 8.5g of borosilicate glass frit were used, and γ-alumina, composite grain bridging modifier, and composite sealing reinforcement were not added. All other components and process parameters were the same as in Example 1.

[0061] The performance of the ceramic tube shells of the fuses obtained in Examples 1-3 and Comparative Examples 1-3 were tested in accordance with national and industry standard testing specifications.

[0062] Bulk density test: Archimedes' displacement method was used. The ceramic tube shell sample to be tested was cut into cubes approximately 10mm × 10mm × 10mm in size. After washing with deionized water, it was dried in an oven at 110℃ for 2 hours. After removal, it was cooled to room temperature in a desiccator, and the dry weight m0 (unit: g, accuracy 0.001g) was measured. The sample was placed in a beaker, completely submerged in deionized water, and boiled on an electric furnace for 2 hours, maintaining the water level above the sample throughout the process. After heating was stopped, it was allowed to cool naturally to room temperature. The sample was removed, and the surface moisture was quickly wiped away with a damp cloth (without absorbing moisture from the pores). The mass m1 (unit: g) of the saturated sample in air was immediately measured. Then, the saturated sample was suspended in a basket in deionized water, and its buoyant weight m2 (unit: g) in the water was measured. The water temperature was recorded as T (unit: ℃), and the density ρ of water at this temperature was taken as 0.997 g / cm³. 3(At 20℃). Calculate the bulk density (unit: g / cm³) using the formula ρ=m0×ρwater / (m1-m2). Five parallel samples were tested for each example and comparative example, and the arithmetic mean was taken.

[0063] Bending strength test: The three-point bending method was used. The ceramic tube shell was axially cut and ground into a long strip specimen with the final dimensions of width b = 4.0 ± 0.1 mm, height h = 3.0 ± 0.1 mm, length L = 40 mm, and test span l = 30 mm. The tensile surface of the specimen was chamfered to 0.1 mm × 0.1 mm. The specimen was placed on the three-point bending fixture of a universal testing machine (accuracy ± 0.5%), with a loading rate of 0.5 mm / min. The indenter and support were made of tungsten carbide with a contact radius of 2.5 mm. Loading was initiated until the specimen fractured, and the maximum fracture load F (unit: N) was recorded. The fracture strength was calculated using the formula σ = 3Fl / (2bh). 2 Calculate the flexural strength (unit: MPa). Five specimens were tested for each example and comparative example, and the arithmetic mean was taken.

[0064] Volume resistivity test: DC three-electrode method was used. The ceramic tube shell was cut and ground on both sides into a circular disc with a diameter φ = 50.0 ± 0.5 mm and a thickness t = 2.0 ± 0.1 mm. After cleaning and drying the sample surface, conductive silver paste was applied to the two sides to be tested and the protective ring position, and then dried at 150℃ for 30 min to form electrodes. The measuring electrode diameter d1 = 25.0 mm, the inner diameter of the protective ring d2 = 30.0 mm, and the outer diameter d3 = 45.0 mm. The effective electrode diameter d0 = (d1 + d2) / 2 = 27.5 mm. Under room temperature (25 ± 2℃) and relative humidity ≤ 40%, the sample was placed in a high-resistivity meter (range 10). 6 -10 16 In a three-electrode test fixture (Ω, accuracy ±5%), a 500VDC voltage is applied between the measuring electrode and the high-voltage electrode. After charging for 1 minute, the resistance value R (unit: Ω) is read. Effective electrode area A = π(d0 / 2) 2 =5.94×10 -4 m². The volume resistivity was calculated using the formula ρv=R×A / t (unit: Ω·m, converted to Ω·cm for easier comparison). Three samples were tested for each embodiment and comparative example, and the arithmetic mean was taken.

[0065] Breakdown voltage test: The arc resistance was evaluated using the power frequency breakdown test method. A ceramic tube shell was cut and ground on both sides into a circular disc with a diameter φ = 50.0 ± 0.5 mm and a thickness t = 1.0 ± 0.05 mm. The sample was placed in transformer oil (breakdown voltage ≥ 60 kV / 2.5 mm), and the oil temperature was maintained at 20 ± 2℃. Cylindrical brass electrodes (upper electrode diameter 25 mm, lower electrode diameter 25 mm, with a 3 mm rounded corner radius at the edges of both electrodes to prevent electric field distortion) were used. The electrode gap was adjusted to just fit the upper and lower surfaces of the sample, ensuring uniform electric field contact. A 50 Hz AC voltage was continuously applied at a boost rate of 0.5 kV / s until the sample broke down (a sharp increase in circuit current or a voltage drop), and the breakdown voltage value U (unit: kV) was recorded. The breakdown field strength E = U / t (unit: kV / mm) was calculated. Five samples were tested for each example and comparative example, and the arithmetic mean was taken.

[0066] The performance test data above are shown in Table 1.

[0067] Table 1: Performance Test Results of Ceramic Tube Shells

[0068]

[0069] The test results in Table 1 above clearly show that, compared with Comparative Examples 1-3, Examples 1-3 have significantly improved in four performance indicators: bulk density, bending strength, volume resistivity, and breakdown voltage. This indicates that the present invention solves the technical problems of insufficient density, low mechanical strength, poor insulation performance, and weak arc resistance of alumina ceramic tube shells in the prior art.

[0070] Specifically, in Comparative Example 1 without the addition of the composite grain bridging agent, the bending strength (238 MPa) and breakdown voltage (18.7 kV / mm) were significantly lower than those in Example 1 (345 MPa, 28.5 kV / mm). This indicates that the composite grain bridging agent effectively solves the problems of poor ceramic toughness and brittle fracture by inducing crack deflection through the formation of a weak interface phase at the grain boundary by lanthanum phosphate and inhibiting abnormal grain growth by strontium zirconate pinning.

[0071] Comparative Example 2, without the addition of composite sealing reinforcement, has a volume resistivity of (0.4 × 10⁻⁶). 12 The breakdown voltage (Ω·cm) and breakdown voltage (16.2kV / mm) compared to Example 1 (1.2×10⁻⁶) were significantly lower. 12 The severe degradation (Ω·cm, 28.5kV / mm) indicates that the magnesium aluminum spinel in the composite sealing agent achieves tight sealing by filling the residual pores, and the trivalent cerium ions in the cerium-doped yttrium aluminum garnet act as electron traps to capture free electrons and block arc electron avalanche, effectively solving the problems of low insulation resistance and poor arc impact resistance.

[0072] Comparative Example 3 lacked both γ-alumina and the composite grain bridging modifier and composite pore-sealing enhancer, resulting in the worst performance in all aspects (density 3.30 g / cm³, strength 185 MPa, resistivity 0.2 × 10⁻⁶). 12 (Ω·cm, breakdown 10.5kV / mm), while Examples 1-3 comprehensively solved the systemic technical problems from matrix densification to grain boundary control to pore sealing and electrical performance enhancement by promoting sintering through γ-alumina reconstructed phase transformation, combined with the synergistic effect of composite grain bridging regulator and composite pore sealing enhancer.

[0073] In summary, the technical solution defined in the claims of this invention achieves a ceramic tube shell for fuses that is highly dense, strong, highly insulating, and highly arc-resistant, overcoming the shortcomings of existing technologies that struggle to balance mechanical and electrical properties.

Claims

1. A method for preparing a ceramic fuse housing, characterized in that the steps include... include: S1. By weight, 70-85 parts of calcined α-alumina, 5-12 parts of borosilicate glass, 3-8 parts of γ-alumina, 2-5 parts of composite grain bridging regulator, 1-4 parts of composite sealing and reinforcing agent, and 65-80 parts of deionized water are placed in a ball mill and ball-milled. The pH is adjusted to 6-8. An aqueous solution containing 1.5-3.0 parts of polyvinyl alcohol is added, and mixing is continued. The mixture is then sieved to obtain a slurry. The slurry is spray-dried to obtain granules. The granules are mixed with 0.3-0.8 parts of magnesium stearate in a mixer to obtain a mixture. The mixture is filled into a mold and pressed to obtain a green body. S2. Place the green billet in a degreasing furnace and heat it to 175-185℃ in an air atmosphere and hold it there; continue to heat it to 295-305℃ and hold it there; continue to heat it to 495-505℃ and hold it there; finally, heat it to 595-605℃ and hold it there to obtain the degreased green billet; transfer the degreased green billet to a sintering furnace, introduce nitrogen gas, heat it to 1350-1480℃ and hold it there; let it cool naturally to room temperature with the furnace.

2. The method for preparing the ceramic shell of the fuse according to claim 1, characterized in that, In step S1, the composition of the borosilicate glass material, based on oxides, includes: 55-65 wt% silicon dioxide, 10-18 wt% boron trioxide, 8-15 wt% aluminum trioxide, 5-10 wt% calcium oxide, 3-7 wt% magnesium oxide, and 1-3 wt% sodium oxide.

3. The method for preparing the ceramic shell of the fuse according to claim 1, characterized in that, In step S2, the holding time for raising the temperature to 175-185℃ is 1-2 hours; the holding time for raising the temperature to 295-305℃ is 1-2 hours; the holding time for raising the temperature to 495-505℃ is 1-2 hours; the holding time for raising the temperature to 595-605℃ is 2-4 hours; and the holding time for raising the temperature to 1350-1480℃ is 2-5 hours.

4. The method for preparing the ceramic shell of the fuse according to claim 1, characterized in that, The preparation method of the composite grain bridging regulator includes: A1. By weight, lanthanum oxide is calcined in a muffle furnace at 795-805℃ to obtain calcined lanthanum oxide; 7.5-9.0 parts of calcined lanthanum oxide and 6.1-7.3 parts of diammonium hydrogen phosphate are added to 25-40 parts of anhydrous ethanol and ball-milled to obtain slurry A; slurry A is dried at 78-82℃ to obtain dried product A; 6.8-8.2 parts of strontium carbonate and 5.7-6.8 parts of zirconium dioxide are added to 25-40 parts of anhydrous ethanol and ball-milled to obtain slurry B; slurry B is dried at 78-82℃ to obtain dried product B. A2. Transfer dried material A to a platinum crucible and heat to 395-405℃ and hold; continue heating to 595-605℃ and hold; continue heating to 1195-1205℃ and hold to obtain lanthanum phosphate powder; put dried material B into a platinum crucible and heat to 1395-1405℃ and hold to obtain strontium zirconate powder; grind the lanthanum phosphate powder and strontium zirconate powder separately, sieve, and mix.

5. The method for preparing the ceramic shell of the fuse according to claim 4, characterized in that, In step A1, the calcination time at 795-805℃ is 2-4 hours.

6. The method for preparing the ceramic shell of the fuse according to claim 4, characterized in that, In step A2, the holding time for raising the temperature to 395-405℃ is 2-4 hours; the holding time for raising the temperature to 595-605℃ is 2-4 hours; the holding time for raising the temperature to 1195-1205℃ is 4-6 hours; and the holding time for raising the temperature to 1395-1405℃ is 6-8 hours.

7. The method for preparing the ceramic shell of the fuse according to claim 1, characterized in that, The preparation method of the composite sealing and reinforcing agent includes: B1. By weight, basic magnesium carbonate is dried at 108-112℃ to obtain dried basic magnesium carbonate; yttrium oxide is calcined in a muffle furnace at 895-905℃ to obtain calcined yttrium oxide; cerium dioxide is calcined in a muffle furnace at 595-605℃ to obtain calcined cerium dioxide; 4.5-5.4 parts of dried basic magnesium carbonate and 7.2-8.7 parts of aluminum hydroxide are added to 25-40 parts of deionized water and ball-milled to obtain slurry C; slurry C is dried at 58-62℃ to obtain dried product C; 4.5-5.5 parts of calcined yttrium oxide, 0.21-0.26 parts of calcined cerium dioxide and 5.3-6.5 parts of aluminum hydroxide are added to 25-40 parts of deionized water and ball-milled to obtain slurry D; slurry D is dried at 58-62℃ to obtain dried product D. B2. Place the dried material C in an alumina crucible and heat it to 595-605℃ in an air atmosphere and hold it there; continue heating to 1495-1505℃ and hold it there to obtain magnesium aluminum spinel powder; place the dried material D in an alumina crucible and heat it to 598-602℃ in an air atmosphere and hold it there; after cooling, transfer it to a tube furnace, introduce a mixture of hydrogen and nitrogen, heat it to 1598-1602℃ and hold it there; cool it down to 298-302℃ and switch to a nitrogen atmosphere to obtain cerium-doped yttrium aluminum garnet powder; pulverize the magnesium aluminum spinel powder and the cerium-doped yttrium aluminum garnet powder separately, sieve them, and mix them.

8. The method for preparing the ceramic shell of the fuse according to claim 7, characterized in that, In step B1, the calcination time is 2-4 hours when the temperature is raised to 895-905℃; the calcination time is 2-4 hours when the temperature is raised to 595-605℃.

9. The method for preparing the ceramic shell of the fuse according to claim 7, characterized in that, In step B2, the holding time for raising the temperature to 595-605℃ is 3-5 hours; the holding time for raising the temperature to 1495-1505℃ is 6-8 hours; the holding time for raising the temperature to 598-602℃ is 3-5 hours; and the holding time for raising the temperature to 1598-1602℃ is 6-8 hours.

10. A ceramic tube shell for a fuse, characterized in that, The ceramic fuse housing is prepared according to the method described in any one of claims 1-9.

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