Ultrafine zirconia nanocomposite powder and its grinding preparation method

Abstract

The present application belongs to the technical field of zirconia refractory parts, and particularly relates to a kind of superfine zirconia nano composite powder and its grinding preparation method. The present application uses fluidized bed combined drying mixing and dry grinding process to prepare superfine premix, and realizes uniform dispersion of nano powder by controlling hot air flow rate and grinding ball parameters; a gradient structure with Y2O6Si2O7 in surface layer is designed to inhibit interfacial stress; combined with molten salt impregnation to fill pores and plasma spraying Al2O3-YAG coating to enhance surface protection. The prepared refractory part has a bulk density of ≥5.85g / cm3, an apparent porosity of ≤0.32%, a bending strength of ≥550MPa, and a glass liquid corrosion depth of ≤0.18mm at 800℃ / 24h. The present application significantly improves the comprehensive performance of the material through raw material processing integration, gradient component design and surface modification technology, and is suitable for high temperature and high corrosion environment such as glass kiln.

Description

Technical Field

[0001] This invention belongs to the field of zirconia refractory components technology, specifically relating to an ultrafine zirconia nanocomposite powder and its grinding preparation method. Background Technology

[0002] Zirconia (ZrO2) refractories are widely used in high-temperature applications such as glass melting furnaces and continuous casting of steel due to their high melting point (2715℃), thermal shock resistance, and chemical resistance. However, traditional zirconia materials suffer from insufficient high-temperature volume stability and weak resistance to glass melt penetration during long-term service, mainly manifested as structural damage caused by grain boundary crack propagation and diffusion of corrosive ions. While existing modification methods, such as adding oxides or optimizing sintering processes, can partially improve performance, achieving a synergistic improvement in bulk density, apparent porosity, flexural strength, and resistance to glass melt penetration remains a challenge for the industry.

[0003] In addition, in terms of raw material processing technology, stepwise drying, mixing and grinding methods can be used to improve the mixing and grinding effect. However, due to the tendency of nanoparticles to agglomerate, it is often necessary to improve the dispersibility by adding dispersants or silane coupling agents. This not only increases the production cost, but may also affect the purity of the material due to the introduction of foreign components, which is not conducive to controlling the density and stability of the mechanical properties of the material. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an ultrafine zirconia nanocomposite powder and its grinding preparation method.

[0005] The first aspect of this invention is to provide a method for preparing ultrafine zirconia nanocomposite powder by grinding.

[0006] The preparation of ultrafine matrix layer powder premix includes the following steps: According to the formula of matrix layer powder raw materials, zirconium dioxide, single crystal alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano alumina, and nano zirconium oxide are put into a fluidized bed drying equipment for combined drying and mixing treatment. The drying temperature is controlled at 115-125℃ and the hot air flow rate is 1.5-3m / s until the moisture content of the material is ≤0.2%. The material is then transferred to a ball mill for dry grinding treatment. Zirconia grinding balls with a diameter of 2-3mm are used, the ball-to-material ratio is controlled at 3-8:1, the rotation speed is 400-700rpm, and the grinding time is 3-5 hours. The material is then passed through a 1200-mesh sieve to obtain ultrafine matrix layer premix.

[0007] The preparation of ultrafine surface layer powder premix includes the following steps: According to the formula of the surface layer powder raw materials, zirconium dioxide, single crystal powdered alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano alumina, nano zirconium oxide, and Y2O6Si2O7 are put into a fluidized bed dryer for combined drying and mixing. The drying temperature is controlled at 115-125℃ and the hot air flow rate is 1.5-3m / s until the moisture content of the material is ≤0.2%. The material is then transferred to a ball mill for dry grinding. Zirconia grinding balls with a diameter of 2-3mm are used, the ball-to-material ratio is controlled at 3-8:1, the rotation speed is 400-700rpm, and the grinding time is 3-5 hours. The material is then passed through a 1200-mesh sieve to obtain the ultrafine surface layer premix.

[0008] As a further optimization of the grinding preparation method for ultrafine zirconia nanocomposite powder, the raw materials of the ultrafine matrix layer premix include the following components:

[0009]

[0010]

[0011] As a further optimization of the grinding preparation method of ultrafine zirconia nanocomposite powder, the raw material of the ultrafine surface layer premix is ​​based on the raw material of the ultrafine matrix layer premix with the addition of 5% by mass of nano Y2O6Si2O7 powder.

[0012] The second aspect of the present invention is to provide an ultrafine zirconia nanocomposite powder, comprising an ultrafine matrix layer powder premix and an ultrafine surface layer premix prepared by the above preparation method.

[0013] Based on this, the present invention also provides a method for preparing refractory parts using the above-mentioned ultrafine zirconia nanocomposite powder, thereby obtaining highly dense zirconia refractory parts with excellent impermeability, which have high bulk density, low apparent porosity, high flexural strength, and excellent resistance to glass melt penetration. The main steps include:

[0014] Mixed raw materials

[0015] Add a 15-20% magnesium dihydrogen phosphate solution to the matrix layer premix, with the amount of magnesium dihydrogen phosphate solution added being 10-20% of the total mass of the raw materials. Wet ball mill for 20-30 minutes to form a uniform slurry; dry and sieve to obtain the matrix layer mixture.

[0016] Add a 15-20% magnesium dihydrogen phosphate solution to the surface layer premix, with the amount of magnesium dihydrogen phosphate solution added being 10-20% of the total mass of the raw materials. Wet ball mill for 20-30 minutes to form a uniform slurry; dry and sieve to obtain the surface layer mixture.

[0017] Fill the raw materials into the shape:

[0018] Fill the mold with a matrix layer mixture, which is 90-95% of the total thickness, and then fill with a surface layer mixture, which is 5-10% of the total thickness; after filling, cold isostatic pressing is performed.

[0019] The formed blank is then sintered.

[0020] The preform is pre-sintered to remove the binder, then pressure sintered under a protective atmosphere, and then hot isostatic pressing is performed on the sintered preform to further eliminate internal defects and improve the material density.

[0021] Post-processing of sintered parts:

[0022] A densified, impermeable zirconia refractory component was prepared by impregnating the sintered part with molten salt and plasma spraying.

[0023] As a further optimization: during the raw material filling and molding process, the cold isostatic pressing pressure is 250-350MPa, and the holding time is 2-5 minutes.

[0024] As a further optimization: During the sintering process of the formed green body, the green body is pre-sintered at 780-820℃ for 1-5 hours with a heating rate of 2-4℃ / min to remove the binder; then, it is subjected to gas pressure sintering at 1600-1700℃ for 1-3 hours with nitrogen gas at 8-12MPa and a heating rate of 4-6℃ / min; then, the sintered green body is subjected to hot isostatic pressing at 1400-1600℃ and 120-180MPa in an argon atmosphere for 0.8-1.5 hours with a cooling rate controlled at ≤5℃ / min to further eliminate internal defects and improve the material density.

[0025] As a further optimization, the oxygen content in the atmosphere used for pre-sintering and gas pressure sintering should be ≤10ppm.

[0026] As a further optimization: during the post-processing of the sintered parts, the sintered parts are immersed in molten borosilicate glass at 1200-1250℃ for 25-40 minutes to fill the surface pores; after immersion, they are allowed to cool naturally and the residual glass phase on the surface is removed.

[0027] As a further optimization: during the post-treatment of sintered parts, after molten salt impregnation, a 30-50μm Al2O3-YAG composite coating is deposited on the surface by plasma spraying.

[0028] Beneficial effects

[0029] This invention utilizes a combination of fluidized bed drying and dry grinding processes to efficiently prepare uniform and ultrafine matrix and surface layer premixes, significantly shortening subsequent wet ball milling time, improving production efficiency, and reducing costs, thus providing technical support for large-scale production. The gradient structure design ensures a gradual decrease in Y content from the surface to the matrix, effectively reducing interfacial stress and suppressing the ZrO2 phase transformation, thereby improving the material's mechanical properties. The (Y,Ce)-O-Si-Al composite glass phase formed by rare earth oxides significantly blocks the diffusion path of corrosive ions, resulting in a significant improvement in impermeability. Molten salt impregnation and plasma spraying post-treatment processes fill surface pores and form an Al2O3-YAG composite coating, further enhancing impermeability. In summary, this invention, through comprehensive optimization of raw material formulation and preparation processes, can produce zirconia refractory parts with high bulk density, low apparent porosity, high flexural strength, and excellent resistance to glass melt penetration, showing broad application prospects in high-temperature, high-permeability environments such as glass furnaces. Detailed Implementation

[0030] The present invention is further illustrated below with specific embodiments. These embodiments are exemplary and intended to illustrate the problem and explain the present invention, and are not intended to be limiting.

[0031] (I) Raw materials and their specifications

[0032] Table 1 Raw Materials and Specifications

[0033]

[0034]

[0035] (II) Basic Powder Raw Materials and Their Usage

[0036]

[0037]

[0038] (III) Preparation Process Steps

[0039] 1. Raw material premixing

[0040] According to the formulation of the matrix layer powder raw materials, zirconium dioxide, single-crystal powdered alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano-alumina, and nano-zirconia are fed into a fluidized bed dryer. The rotary mixer is turned on (speed 1200-2000 rpm), and hot air at a temperature of 115-125℃ and a flow rate of 1.5-3 m / s is introduced for drying for 30-120 minutes, controlling the material moisture content to ≤0.2%. Then, the material is transferred to a planetary ball mill for dry grinding using zirconium oxide grinding balls (diameter 2-3 mm, ball-to-material ratio 3:1-8:1) at a speed of 400-700 rpm for 3-5 hours. After passing through a 1200-mesh sieve, an ultrafine, uniformly mixed matrix layer premix is ​​obtained.

[0041] The surface layer mixture is made by adding 5% by mass of nano-Y₂O₆Si₂O₇ powder to the base layer formulation. According to the surface layer powder raw material formulation, zirconium dioxide, single-crystal powdered alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano-alumina, nano-zirconia, and Y₂O₆Si₂O₇ are fed into a fluidized bed dryer. A rotary mixer is turned on (1500 rpm), and hot air at 115-125℃ and a flow rate of 1.5-3 m / s is simultaneously introduced for drying for 30-120 minutes, controlling the material moisture content to ≤0.2%. The material is then transferred to a planetary ball mill for dry grinding using zirconium oxide grinding balls (2-3 mm in diameter, ball-to-material ratio 3:1-8:1) at 400-700 rpm for 3-5 hours. The mixture is then passed through a 1200-mesh sieve to obtain an ultrafine, uniformly mixed surface layer premix.

[0042] 2. Mixing raw materials

[0043] A 15-20% magnesium dihydrogen phosphate solution is added to the matrix layer premix, with the amount of magnesium dihydrogen phosphate solution added being 10-20% of the total mass of the raw materials. The mixture is then wet-milled for 20-30 minutes to form a homogeneous slurry. After drying the slurry at 80℃ for 12 hours, it is passed through a 100-mesh sieve to obtain the matrix layer mixture for later use.

[0044] Add a 15-20% magnesium dihydrogen phosphate solution to the surface layer premix, with the amount of magnesium dihydrogen phosphate solution added being 10-20% of the total mass of the raw materials. Perform wet ball milling for 20-30 minutes to form a homogeneous slurry. After drying the slurry at 80℃ for 12 hours, pass it through a 100-mesh sieve to obtain the surface layer mixture for later use.

[0045] 3. Molding

[0046] The molding process employs layered filling and cold isostatic pressing (CIP) technology. First, a matrix layer mixture is filled into the mold, with a thickness of 90-95% of the total thickness. Then, a surface layer mixture is filled, with a thickness of 5-10% of the total thickness. After filling, cold isostatic pressing is used at a pressure of 300 MPa for a holding time of 3 minutes to ensure the density and uniformity of the preform.

[0047] 4. Sintering

[0048] The sintering process includes three steps: pre-sintering, gas pressure sintering, and hot isostatic pressing. First, the formed green body is pre-sintered at 800℃ for 2 hours with a heating rate of 3℃ / min to remove the binder. Then, it undergoes gas pressure sintering at 1600-1700℃ for 2 hours, with nitrogen gas at 10MPa introduced and a heating rate of 5℃ / min. Finally, the sintered green body is subjected to hot isostatic pressing at 1500℃ and 150MPa argon atmosphere for 1 hour, with a cooling rate controlled at ≤5℃ / min, to further eliminate internal defects and improve material density. High-purity inert gases (nitrogen or argon) with an oxygen content ≤10ppm are used in the pre-sintering and gas pressure sintering processes.

[0049] 5. Post-processing

[0050] The post-treatment process includes two steps: molten salt impregnation and plasma spraying. First, the sintered part is immersed in molten borosilicate glass at 1200-1250℃ for 30 minutes to fill surface pores. After impregnation, it is allowed to cool naturally to remove any residual glass phase. Subsequently, a 30-50 μm Al₂O₃-YAG composite coating is deposited on the surface using plasma spraying. The spraying parameters are: current 500A, gas flow rate Ar / H₂ = 45 / 15 SLPM, spraying distance 80 mm, and spraying speed 200 mm / s. This produces a dense, impermeable zirconia refractory part.

[0051] Example 1

[0052] Basic powder raw materials and their dosage

[0053]

[0054] 1. Raw material premixing

[0055] According to the formula of the basic powder raw materials, zirconium dioxide, single-crystal powdered alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano-alumina, and nano-zirconia are fed into a fluidized bed dryer. The rotary mixer is turned on (speed 1500 rpm), and hot air at 120℃ and flow rate 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. Then the material is transferred to a planetary ball mill for dry grinding using zirconium oxide grinding balls (diameter 3 mm, ball-to-material ratio 5:1) at 500 rpm for 4 hours. After passing through a 1200-mesh sieve, an ultrafine, uniformly mixed matrix layer premix is ​​obtained.

[0056] The surface layer mixture is made by adding 5% by mass of nano-Y2O6Si2O7 powder to the matrix layer formulation. The raw materials are fed into a fluidized bed dryer according to the specified ratio, and a rotary mixer is turned on (1500 rpm). Simultaneously, hot air at 120℃ and a flow rate of 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. The material is then transferred to a planetary ball mill for dry grinding using zirconia grinding balls (3 mm diameter, ball-to-material ratio 5:1) at 500 rpm for 4 hours. The mixture is then passed through a 1200-mesh sieve to obtain an ultrafine, uniformly mixed surface layer premix.

[0057] 2. Mixing raw materials

[0058] An 18% magnesium dihydrogen phosphate solution was added to the matrix layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 25 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the matrix layer mixture for later use.

[0059] An 18% magnesium dihydrogen phosphate solution was added to the surface layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 30 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the surface layer mixture for later use.

[0060] 3. Molding

[0061] The molding process employs layered filling and cold isostatic pressing (CIP) technology. First, a matrix layer mixture is filled into the mold, with a thickness of 90% of the total thickness. Then, a surface layer mixture is filled, with a thickness of 10% of the total thickness. After filling, cold isostatic pressing is used at a pressure of 300 MPa for a holding time of 3 minutes to ensure the density and uniformity of the blank.

[0062] 4. Sintering

[0063] The sintering process includes three steps: pre-sintering, gas pressure sintering, and hot isostatic pressing. First, the formed green body is pre-sintered at 800℃ for 2 hours with a heating rate of 3℃ / min to remove the binder. Then, it undergoes gas pressure sintering at 1600℃ for 2 hours, with nitrogen gas at 10MPa introduced and a heating rate of 5℃ / min. Finally, the sintered green body is subjected to hot isostatic pressing at 1500℃ and 150MPa argon atmosphere for 1 hour, with a cooling rate controlled at ≤5℃ / min, to further eliminate internal defects and improve material density. High-purity inert gases (nitrogen or argon) with an oxygen content ≤10ppm are used in the pre-sintering and gas pressure sintering processes.

[0064] 5. Post-processing

[0065] The post-treatment process includes two steps: molten salt impregnation and plasma spraying. First, the sintered part is immersed in molten borosilicate glass at 1200℃ for 30 minutes to fill surface pores. After impregnation, it is allowed to cool naturally to remove any residual glass phase. Subsequently, a 30μm Al₂O₃-YAG composite coating is deposited on the surface using plasma spraying. The spraying parameters are: current 500A, gas flow rate Ar / H₂ = 45 / 15 SLPM, spraying distance 80mm, and spraying speed 200mm / s. This produces a dense, impermeable zirconia refractory part.

[0066] Example 2

[0067] Basic powder raw materials and their dosage

[0068]

[0069]

[0070] 1. Raw material premixing

[0071] According to the formula of the basic powder raw materials, zirconium dioxide, single-crystal powdered alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano-alumina, and nano-zirconia are fed into a fluidized bed dryer. The rotary mixer is turned on (speed 1500 rpm), and hot air at 120℃ and flow rate 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. Then the material is transferred to a planetary ball mill for dry grinding using zirconium oxide grinding balls (diameter 3 mm, ball-to-material ratio 5:1) at 500 rpm for 4 hours. After passing through a 1200-mesh sieve, an ultrafine, uniformly mixed matrix layer premix is ​​obtained.

[0072] The surface layer mixture is made by adding 5% by mass of nano-Y2O6Si2O7 powder to the matrix layer formulation. The raw materials are fed into a fluidized bed dryer according to the specified ratio, and a rotary mixer is turned on (1500 rpm). Simultaneously, hot air at 120℃ and a flow rate of 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. The material is then transferred to a planetary ball mill for dry grinding using zirconia grinding balls (3 mm diameter, ball-to-material ratio 5:1) at 500 rpm for 4 hours. The mixture is then passed through a 1200-mesh sieve to obtain an ultrafine, uniformly mixed surface layer premix.

[0073] 2. Mixing raw materials

[0074] An 18% magnesium dihydrogen phosphate solution was added to the matrix layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 25 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the matrix layer mixture for later use.

[0075] An 18% magnesium dihydrogen phosphate solution was added to the surface layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 30 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the surface layer mixture for later use.

[0076] 3. Molding

[0077] The molding process employs layered filling and cold isostatic pressing (CIP) technology. First, a matrix layer mixture is filled into the mold, with a thickness of 95% of the total thickness. Then, a surface layer mixture is filled, with a thickness of 5% of the total thickness. After filling, cold isostatic pressing is used at a pressure of 300 MPa for a holding time of 3 minutes to ensure the density and uniformity of the preform.

[0078] 4. Sintering

[0079] The sintering process includes three steps: pre-sintering, gas pressure sintering, and hot isostatic pressing. First, the formed green body is pre-sintered at 800℃ for 2 hours with a heating rate of 3℃ / min to remove the binder. Then, it undergoes gas pressure sintering at 1700℃ for 2 hours, with nitrogen gas at 10MPa introduced and a heating rate of 5℃ / min. Finally, the sintered green body is subjected to hot isostatic pressing at 1500℃ and 150MPa argon atmosphere for 1 hour, with a cooling rate controlled at ≤5℃ / min, to further eliminate internal defects and improve material density. High-purity inert gases (nitrogen or argon) with an oxygen content ≤10ppm are used in the pre-sintering and gas pressure sintering processes.

[0080] 5. Post-processing

[0081] The post-treatment process includes two steps: molten salt impregnation and plasma spraying. First, the sintered part is immersed in molten borosilicate glass at 1250℃ for 30 minutes to fill surface pores. After impregnation, it is allowed to cool naturally to remove any residual glass phase. Subsequently, a 50μm Al₂O₃-YAG composite coating is deposited on the surface using plasma spraying. The spraying parameters are: current 500A, gas flow rate Ar / H₂ = 45 / 15 SLPM, spraying distance 80mm, and spraying speed 200mm / s. This produces a dense, impermeable zirconia refractory part.

[0082] Example 3

[0083] Basic powder raw materials and their dosage

[0084]

[0085] 1. Raw material premixing

[0086] According to the formula of the basic powder raw materials, zirconium dioxide, single-crystal powdered alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano-alumina, and nano-zirconia are fed into a fluidized bed dryer. The rotary mixer is turned on (speed 1500 rpm), and hot air at 120℃ and flow rate 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. Then the material is transferred to a planetary ball mill for dry grinding using zirconium oxide grinding balls (diameter 3 mm, ball-to-material ratio 5:1) at 500 rpm for 4 hours. After passing through a 1200-mesh sieve, an ultrafine, uniformly mixed matrix layer premix is ​​obtained.

[0087] The surface layer mixture is made by adding 5% by mass of nano-Y2O6Si2O7 powder to the matrix layer formulation. The raw materials are fed into a fluidized bed dryer according to the specified ratio, and a rotary mixer is turned on (1500 rpm). Simultaneously, hot air at 120℃ and a flow rate of 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. The material is then transferred to a planetary ball mill for dry grinding using zirconia grinding balls (3 mm diameter, ball-to-material ratio 5:1) at 500 rpm for 4 hours. The mixture is then passed through a 1200-mesh sieve to obtain an ultrafine, uniformly mixed surface layer premix.

[0088] 2. Mixing raw materials

[0089] An 18% magnesium dihydrogen phosphate solution was added to the matrix layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 25 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the matrix layer mixture for later use.

[0090] An 18% magnesium dihydrogen phosphate solution was added to the surface layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 30 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the surface layer mixture for later use.

[0091] 3. Molding

[0092] The molding process employs layered filling and cold isostatic pressing (CIP) technology. First, a matrix layer mixture is filled into the mold, with a thickness of 90% of the total thickness. Then, a surface layer mixture is filled, with a thickness of 10% of the total thickness. After filling, cold isostatic pressing is used at a pressure of 300 MPa for a holding time of 3 minutes to ensure the density and uniformity of the blank.

[0093] 4. Sintering

[0094] The sintering process includes three steps: pre-sintering, gas pressure sintering, and hot isostatic pressing. First, the formed green body is pre-sintered at 800℃ for 2 hours with a heating rate of 3℃ / min to remove the binder. Then, it undergoes gas pressure sintering at 1650℃ for 2 hours, with nitrogen gas at 10MPa introduced and a heating rate of 5℃ / min. Finally, the sintered green body is subjected to hot isostatic pressing at 1500℃ and 150MPa argon atmosphere for 1 hour, with a cooling rate controlled at ≤5℃ / min, to further eliminate internal defects and improve material density. High-purity inert gases (nitrogen or argon) with an oxygen content ≤10ppm are used in the pre-sintering and gas pressure sintering processes.

[0095] 5. Post-processing

[0096] The post-treatment process includes two steps: molten salt impregnation and plasma spraying. First, the sintered part is immersed in molten borosilicate glass at 1250℃ for 30 minutes to fill surface pores. After impregnation, it is allowed to cool naturally to remove any residual glass phase. Subsequently, a 50μm Al₂O₃-YAG composite coating is deposited on the surface using plasma spraying. The spraying parameters are: current 500A, gas flow rate Ar / H₂ = 45 / 15 SLPM, spraying distance 80mm, and spraying speed 200mm / s. This produces a dense, impermeable zirconia refractory part.

[0097] Example 4

[0098] Basic powder raw materials and their dosage

[0099]

[0100]

[0101] 1. Raw material premixing

[0102] According to the formula of the basic powder raw materials, zirconium dioxide, single-crystal powdered alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano-alumina, and nano-zirconia are fed into a fluidized bed dryer. The rotary mixer is turned on (speed 1500 rpm), and hot air at 120℃ and flow rate 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. Then the material is transferred to a planetary ball mill for dry grinding using zirconium oxide grinding balls (diameter 3 mm, ball-to-material ratio 5:1) at 500 rpm for 4 hours. After passing through a 1200-mesh sieve, an ultrafine, uniformly mixed matrix layer premix is ​​obtained.

[0103] The surface layer mixture is made by adding 5% by mass of nano-Y2O6Si2O7 powder to the matrix layer formulation. The raw materials are fed into a fluidized bed dryer according to the specified ratio, and a rotary mixer is turned on (1500 rpm). Simultaneously, hot air at 120℃ and a flow rate of 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. The material is then transferred to a planetary ball mill for dry grinding using zirconia grinding balls (3 mm diameter, ball-to-material ratio 5:1) at 500 rpm for 4 hours. The mixture is then passed through a 1200-mesh sieve to obtain an ultrafine, uniformly mixed surface layer premix.

[0104] 2. Mixing raw materials

[0105] An 18% magnesium dihydrogen phosphate solution was added to the matrix layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 25 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the matrix layer mixture for later use.

[0106] An 18% magnesium dihydrogen phosphate solution was added to the surface layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 30 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the surface layer mixture for later use.

[0107] 3. Molding

[0108] The molding process employs layered filling and cold isostatic pressing (CIP) technology. First, a matrix layer mixture is filled into the mold, with a thickness of 95% of the total thickness. Then, a surface layer mixture is filled, with a thickness of 5% of the total thickness. After filling, cold isostatic pressing is used at a pressure of 300 MPa for a holding time of 3 minutes to ensure the density and uniformity of the preform.

[0109] 4. Sintering

[0110] The sintering process includes three steps: pre-sintering, gas pressure sintering, and hot isostatic pressing. First, the formed green body is pre-sintered at 800℃ for 2 hours with a heating rate of 3℃ / min to remove the binder. Then, it undergoes gas pressure sintering at 1600℃ for 2 hours, with nitrogen gas at 10MPa introduced and a heating rate of 5℃ / min. Finally, the sintered green body is subjected to hot isostatic pressing at 1500℃ and 150MPa argon atmosphere for 1 hour, with a cooling rate controlled at ≤5℃ / min, to further eliminate internal defects and improve material density. High-purity inert gases (nitrogen or argon) with an oxygen content ≤10ppm are used in the pre-sintering and gas pressure sintering processes.

[0111] 5. Post-processing

[0112] The post-treatment process includes two steps: molten salt impregnation and plasma spraying. First, the sintered part is immersed in molten borosilicate glass at 1250℃ for 30 minutes to fill surface pores. After impregnation, it is allowed to cool naturally to remove any residual glass phase. Subsequently, a 30μm Al₂O₃-YAG composite coating is deposited on the surface using plasma spraying. The spraying parameters are: current 500A, gas flow rate Ar / H₂ = 45 / 15 SLPM, spraying distance 80mm, and spraying speed 200mm / s. This produces a densified, impermeable zirconia refractory part.

[0113] Example 5

[0114] Basic powder raw materials and their dosage

[0115]

[0116] 1. Raw material premixing

[0117] According to the formula of the basic powder raw materials, zirconium dioxide, single-crystal powdered alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano-alumina, and nano-zirconia are fed into a fluidized bed dryer. The rotary mixer is turned on (speed 1500 rpm), and hot air at 120℃ and flow rate 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. Then the material is transferred to a planetary ball mill for dry grinding using zirconium oxide grinding balls (diameter 3 mm, ball-to-material ratio 5:1) at 500 rpm for 4 hours. After passing through a 1200-mesh sieve, an ultrafine, uniformly mixed matrix layer premix is ​​obtained.

[0118] The surface layer mixture is made by adding 5% by mass of nano-Y2O6Si2O7 powder to the matrix layer formulation. The raw materials are fed into a fluidized bed dryer according to the specified ratio, and a rotary mixer is turned on (1500 rpm). Simultaneously, hot air at 120℃ and a flow rate of 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. The material is then transferred to a planetary ball mill for dry grinding using zirconia grinding balls (3 mm diameter, ball-to-material ratio 5:1) at 500 rpm for 4 hours. The mixture is then passed through a 1200-mesh sieve to obtain an ultrafine, uniformly mixed surface layer premix.

[0119] 2. Mixing raw materials

[0120] An 18% magnesium dihydrogen phosphate solution was added to the matrix layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 25 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the matrix layer mixture for later use.

[0121] An 18% magnesium dihydrogen phosphate solution was added to the surface layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 30 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the surface layer mixture for later use.

[0122] 3. Molding

[0123] The molding process employs layered filling and cold isostatic pressing (CIP) technology. First, a matrix layer mixture is filled into the mold, with a thickness of 95% of the total thickness. Then, a surface layer mixture is filled, with a thickness of 5% of the total thickness. After filling, cold isostatic pressing is used at a pressure of 300 MPa for a holding time of 3 minutes to ensure the density and uniformity of the preform.

[0124] 4. Sintering

[0125] The sintering process includes three steps: pre-sintering, gas pressure sintering, and hot isostatic pressing. First, the formed green body is pre-sintered at 800℃ for 2 hours with a heating rate of 3℃ / min to remove the binder. Then, it undergoes gas pressure sintering at 1700℃ for 2 hours, with nitrogen gas at 10MPa introduced and a heating rate of 5℃ / min. Finally, the sintered green body is subjected to hot isostatic pressing at 1500℃ and 150MPa argon atmosphere for 1 hour, with a cooling rate controlled at ≤5℃ / min, to further eliminate internal defects and improve material density. High-purity inert gases (nitrogen or argon) with an oxygen content ≤10ppm are used in the pre-sintering and gas pressure sintering processes.

[0126] 5. Post-processing

[0127] The post-treatment process includes two steps: molten salt impregnation and plasma spraying. First, the sintered part is immersed in molten borosilicate glass at 1200℃ for 30 minutes to fill surface pores. After impregnation, it is allowed to cool naturally to remove any residual glass phase. Subsequently, a 30μm Al₂O₃-YAG composite coating is deposited on the surface using plasma spraying. The spraying parameters are: current 500A, gas flow rate Ar / H₂ = 45 / 15 SLPM, spraying distance 80mm, and spraying speed 200mm / s. This produces a dense, impermeable zirconia refractory part.

[0128] Example 6

[0129] Basic powder raw materials and their dosage

[0130]

[0131]

[0132] 1. Raw material premixing

[0133] According to the formula of the basic powder raw materials, zirconium dioxide, single-crystal powdered alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano-alumina, and nano-zirconia are fed into a fluidized bed dryer. The rotary mixer is turned on (speed 1500 rpm), and hot air at 120℃ and flow rate 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. Then the material is transferred to a planetary ball mill for dry grinding using zirconium oxide grinding balls (diameter 3 mm, ball-to-material ratio 5:1) at 500 rpm for 4 hours. After passing through a 1200-mesh sieve, an ultrafine, uniformly mixed matrix layer premix is ​​obtained.

[0134] The surface layer mixture is made by adding 5% by mass of nano-Y2O6Si2O7 powder to the matrix layer formulation. The raw materials are fed into a fluidized bed dryer according to the specified ratio, and a rotary mixer is turned on (1500 rpm). Simultaneously, hot air at 120℃ and a flow rate of 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. The material is then transferred to a planetary ball mill for dry grinding using zirconia grinding balls (3 mm diameter, ball-to-material ratio 5:1) at 500 rpm for 4 hours. The mixture is then passed through a 1200-mesh sieve to obtain an ultrafine, uniformly mixed surface layer premix.

[0135] 2. Mixing raw materials

[0136] An 18% magnesium dihydrogen phosphate solution was added to the matrix layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 25 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the matrix layer mixture for later use.

[0137] An 18% magnesium dihydrogen phosphate solution was added to the surface layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 30 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the surface layer mixture for later use.

[0138] 3. Molding

[0139] The molding process employs layered filling and cold isostatic pressing (CIP) technology. First, a matrix layer mixture is filled into the mold, with a thickness of 90% of the total thickness. Then, a surface layer mixture is filled, with a thickness of 10% of the total thickness. After filling, cold isostatic pressing is used at a pressure of 300 MPa for a holding time of 3 minutes to ensure the density and uniformity of the blank.

[0140] 4. Sintering

[0141] The sintering process includes three steps: pre-sintering, gas pressure sintering, and hot isostatic pressing. First, the formed green body is pre-sintered at 800℃ for 2 hours with a heating rate of 3℃ / min to remove the binder. Then, it undergoes gas pressure sintering at 1650℃ for 2 hours, with nitrogen gas at 10MPa introduced and a heating rate of 5℃ / min. Finally, the sintered green body is subjected to hot isostatic pressing at 1500℃ and 150MPa argon atmosphere for 1 hour, with a cooling rate controlled at ≤5℃ / min, to further eliminate internal defects and improve material density. High-purity inert gases (nitrogen or argon) with an oxygen content ≤10ppm are used in the pre-sintering and gas pressure sintering processes.

[0142] 5. Post-processing

[0143] The post-treatment process includes two steps: molten salt impregnation and plasma spraying. First, the sintered part is immersed in molten borosilicate glass at 1200℃ for 30 minutes to fill surface pores. After impregnation, it is allowed to cool naturally to remove any residual glass phase. Subsequently, a 40μm Al₂O₃-YAG composite coating is deposited on the surface using plasma spraying. The spraying parameters are: current 500A, gas flow rate Ar / H₂ = 45 / 15 SLPM, spraying distance 80mm, and spraying speed 200mm / s. This produces a dense, impermeable zirconia refractory part.

[0144] Comparative Example 1

[0145] Compared to Example 3, Comparative Example 1 did not distinguish between the matrix layer mixture and the surface layer mixture, but instead used the same matrix layer mixture for integral molding.

[0146] Basic powder raw materials and their dosage

[0147] 1150 parts by weight of zirconium dioxide;

[0148] 255 parts by weight of single-crystal powdered alumina;

[0149] 150 parts by weight of fused silica powder;

[0150] 75 parts by weight of boron compound;

[0151] 50 parts by weight of rare earth oxides;

[0152] 30 parts by weight of silicon carbide whiskers;

[0153] 80 parts by weight of nano-alumina;

[0154] 30 parts by weight of nano-zirconia.

[0155] 1. Raw material premixing

[0156] According to the formula of the basic powder raw materials, zirconium dioxide, single-crystal powdered alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano-alumina, and nano-zirconia are fed into a fluidized bed dryer. The rotary mixer is turned on (speed 1500 rpm), and hot air at 120℃ and flow rate 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. Then the material is transferred to a planetary ball mill for dry grinding using zirconium oxide grinding balls (diameter 3 mm, ball-to-material ratio 5:1) at 500 rpm for 4 hours. After passing through a 1200-mesh sieve, an ultrafine, uniformly mixed matrix layer premix is ​​obtained.

[0157] 2. Mixing raw materials

[0158] An 18% magnesium dihydrogen phosphate solution was added to the matrix layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 25 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the matrix layer mixture for later use.

[0159] 3. Molding

[0160] The matrix layer mixture is filled into the mold. After filling, cold isostatic pressing is used to form the blank. The pressure is 300MPa and the holding time is 3 minutes to ensure the density and uniformity of the blank.

[0161] 4. Sintering

[0162] The sintering process includes three steps: pre-sintering, gas pressure sintering, and hot isostatic pressing. First, the formed green body is pre-sintered at 800℃ for 2 hours with a heating rate of 3℃ / min to remove the binder. Then, it undergoes gas pressure sintering at 1650℃ for 2 hours, with nitrogen gas at 10MPa introduced and a heating rate of 5℃ / min. Finally, the sintered green body is subjected to hot isostatic pressing at 1500℃ and 150MPa argon atmosphere for 1 hour, with a cooling rate controlled at ≤5℃ / min, to further eliminate internal defects and improve material density. High-purity inert gases (nitrogen or argon) with an oxygen content ≤10ppm are used in the pre-sintering and gas pressure sintering processes.

[0163] 5. Post-processing

[0164] The post-treatment process includes two steps: molten salt impregnation and plasma spraying. First, the sintered part is immersed in molten borosilicate glass at 1250℃ for 30 minutes to fill surface pores. After impregnation, it is allowed to cool naturally to remove any residual glass phase. Subsequently, a 50μm Al₂O₃-YAG composite coating is deposited on the surface using plasma spraying. The spraying parameters are: current 500A, gas flow rate Ar / H₂ = 45 / 15 SLPM, spraying distance 80mm, and spraying speed 200mm / s. This produces a dense, impermeable zirconia refractory part.

[0165] Comparative Example 2

[0166] Compared to Example 3, no rare earth oxides were added to the raw materials in Comparative Example 2.

[0167] Basic powder raw materials and their dosage

[0168]

[0169] 1. Raw material premixing

[0170] According to the formula of the basic powder raw materials, zirconium dioxide, single-crystal powdered alumina, fused silica powder, boron compounds, silicon carbide whiskers, nano-alumina, and nano-zirconia were fed into a fluidized bed dryer. The rotary mixer was turned on (1500 rpm), and hot air at 120℃ and a flow rate of 2 m / s was introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. Then, the material was transferred to a planetary ball mill for dry grinding using zirconium oxide grinding balls (3 mm in diameter, ball-to-material ratio 5:1) at 500 rpm for 4 hours. After passing through a 1200-mesh sieve, an ultrafine, uniformly mixed matrix layer premix was obtained.

[0171] The surface layer mixture is made by adding 5% by mass of nano-Y2O6Si2O7 powder to the matrix layer formulation. The raw materials are fed into a fluidized bed dryer according to the specified ratio, and a rotary mixer is turned on (1500 rpm). Simultaneously, hot air at 120℃ and a flow rate of 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. The material is then transferred to a planetary ball mill for dry grinding using zirconia grinding balls (3 mm diameter, ball-to-material ratio 5:1) at 500 rpm for 4 hours. The mixture is then passed through a 1200-mesh sieve to obtain an ultrafine, uniformly mixed surface layer premix.

[0172] 2. Mixing raw materials

[0173] An 18% magnesium dihydrogen phosphate solution was added to the matrix layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 25 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the matrix layer mixture for later use.

[0174] An 18% magnesium dihydrogen phosphate solution was added to the surface layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 30 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the surface layer mixture for later use.

[0175] 3. Molding

[0176] The molding process employs layered filling and cold isostatic pressing (CIP) technology. First, a matrix layer mixture is filled into the mold, with a thickness of 90% of the total thickness. Then, a surface layer mixture is filled, with a thickness of 10% of the total thickness. After filling, cold isostatic pressing is used at a pressure of 300 MPa for a holding time of 3 minutes to ensure the density and uniformity of the blank.

[0177] 4. Sintering

[0178] The sintering process includes three steps: pre-sintering, gas pressure sintering, and hot isostatic pressing. First, the formed green body is pre-sintered at 800℃ for 2 hours with a heating rate of 3℃ / min to remove the binder. Then, it undergoes gas pressure sintering at 1650℃ for 2 hours, with nitrogen gas at 10MPa introduced and a heating rate of 5℃ / min. Finally, the sintered green body is subjected to hot isostatic pressing at 1500℃ and 150MPa argon atmosphere for 1 hour, with a cooling rate controlled at ≤5℃ / min, to further eliminate internal defects and improve material density. High-purity inert gases (nitrogen or argon) with an oxygen content ≤10ppm are used in the pre-sintering and gas pressure sintering processes.

[0179] 5. Post-processing

[0180] The post-treatment process includes two steps: molten salt impregnation and plasma spraying. First, the sintered part is immersed in molten borosilicate glass at 1250℃ for 30 minutes to fill surface pores. After impregnation, it is allowed to cool naturally to remove any residual glass phase. Subsequently, a 50μm Al₂O₃-YAG composite coating is deposited on the surface using plasma spraying. The spraying parameters are: current 500A, gas flow rate Ar / H₂ = 45 / 15 SLPM, spraying distance 80mm, and spraying speed 200mm / s. This produces a dense, impermeable zirconia refractory part.

[0181] Comparative Example 3

[0182] Compared to Example 3, Comparative Example 3 omitted the molten salt impregnation step in the post-processing.

[0183] Basic powder raw materials and their dosage

[0184]

[0185] 1. Raw material premixing

[0186] According to the formula of the basic powder raw materials, zirconium dioxide, single-crystal powdered alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano-alumina, and nano-zirconia are fed into a fluidized bed dryer. The rotary mixer is turned on (speed 1500 rpm), and hot air at 120℃ and flow rate 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. Then the material is transferred to a planetary ball mill for dry grinding using zirconium oxide grinding balls (diameter 3 mm, ball-to-material ratio 5:1) at 500 rpm for 4 hours. After passing through a 1200-mesh sieve, an ultrafine, uniformly mixed matrix layer premix is ​​obtained.

[0187] The surface layer mixture is made by adding 5% by mass of nano-Y2O6Si2O7 powder to the matrix layer formulation. The raw materials are fed into a fluidized bed dryer according to the specified ratio, and a rotary mixer is turned on (1500 rpm). Simultaneously, hot air at 120℃ and a flow rate of 2 m / s is introduced for drying for 60 minutes, controlling the material moisture content to ≤0.2%. The material is then transferred to a planetary ball mill for dry grinding using zirconia grinding balls (3 mm diameter, ball-to-material ratio 5:1) at 500 rpm for 4 hours. The mixture is then passed through a 1200-mesh sieve to obtain an ultrafine, uniformly mixed surface layer premix.

[0188] 2. Mixing raw materials

[0189] An 18% magnesium dihydrogen phosphate solution was added to the matrix layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 25 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the matrix layer mixture for later use.

[0190] An 18% magnesium dihydrogen phosphate solution was added to the surface layer premix, with the amount of magnesium dihydrogen phosphate solution added being 15% of the total mass of the raw materials. The mixture was then wet-milled for 30 minutes to form a homogeneous slurry. After drying the slurry at 80°C for 12 hours, it was passed through a 100-mesh sieve to obtain the surface layer mixture for later use.

[0191] 3. Molding

[0192] The molding process employs layered filling and cold isostatic pressing (CIP) technology. First, a matrix layer mixture is filled into the mold, with a thickness of 90% of the total thickness. Then, a surface layer mixture is filled, with a thickness of 10% of the total thickness. After filling, cold isostatic pressing is used at a pressure of 300 MPa for a holding time of 3 minutes to ensure the density and uniformity of the blank.

[0193] 4. Sintering

[0194] The sintering process includes three steps: pre-sintering, gas pressure sintering, and hot isostatic pressing. First, the formed green body is pre-sintered at 800℃ for 2 hours with a heating rate of 3℃ / min to remove the binder. Then, it undergoes gas pressure sintering at 1650℃ for 2 hours, with nitrogen gas at 10MPa introduced and a heating rate of 5℃ / min. Finally, the sintered green body is subjected to hot isostatic pressing at 1500℃ and 150MPa argon atmosphere for 1 hour, with a cooling rate controlled at ≤5℃ / min, to further eliminate internal defects and improve material density. High-purity inert gases (nitrogen or argon) with an oxygen content ≤10ppm are used in the pre-sintering and gas pressure sintering processes.

[0195] 5. Post-processing

[0196] The post-treatment was a plasma spraying step. A 50 μm Al2O3-YAG composite coating was deposited on the surface using plasma spraying technology. The spraying parameters were: current 500A, gas flow rate Ar / H2 = 45 / 15 SLPM, spraying distance 80 mm, and spraying speed 200 mm / s. A dense, impermeable zirconia refractory component was thus produced.

[0197] Table 2 Performance Test Results

[0198]

[0199]

[0200] As shown in Table 2, the zirconia refractory parts prepared by this invention have a bulk density of ≥5.85 g / cm³. 3 It exhibits excellent performance in terms of apparent porosity (≤0.32%), flexural strength (≥550MPa), and resistance to glass melt penetration (erosion depth ≤0.18mm). Among these, Example 3 demonstrates outstanding performance, with a bulk density of 6.01g / cm³. 3 The apparent porosity is 0.25%, the flexural strength is 600 MPa, and the erosion depth resisted by molten glass penetration is 0.10 mm. Combined with the test results of the comparative example, it can be seen that the excellent comprehensive performance stems from the combined effect of gradient structure, grain boundary regulation, and surface defect repair.

[0201] Specifically, in the zirconia refractory surface layer prepared by this invention, Y₂O₆Si₂O₇ forms a continuous Y-Si-O transition layer with the ZrO₂ matrix, resulting in a gradient decrease in Y element content from the surface to the matrix. This gradient structure reduces the coefficient of thermal expansion from approximately 5.8 × 10⁻⁶ on the surface to approximately 5.8 × 10⁻⁶ on the matrix. -6 / ℃ transitions smoothly to 10.5×10 in the matrix. -6 At / ℃, the interfacial stress is significantly reduced. This gradient structure effectively suppresses the transformation of the ZrO2 phase into the monoclinic phase, endowing the material with excellent flexural strength and impermeability. The Y in the material... 3 + / Ce 4 It exists in solid solution form at the ZrO2 grain boundaries, forming a (Y,Ce)-O-Si-Al composite glass phase. This high-viscosity glass phase can effectively block Ca. 2 The diffusion pathways of eroding ions such as Na+ and α+ minimize the erosion depth in the glass melt erosion test, with Example 3 showing an erosion depth of 0.10 mm, a 75% reduction compared to Comparative Example 2 (0.40 mm) without rare earth elements. Simultaneously, rare earth doping further enhances the grain boundary bonding energy, contributing to improved bending resistance. During post-treatment, molten salt impregnation significantly reduces surface porosity, and the B2O3-SiO2 glass phase fills defects >1 μm in size through capillary action.

[0202] Furthermore, in the raw material processing stage, by combining drying and mixing followed by dry milling, ultrafine and uniformly mixed matrix and surface layer premixes can be obtained efficiently. This significantly shortens the subsequent wet ball milling time and facilitates the batch preparation of premixes, making it particularly suitable for large-scale production scenarios and significantly improving production efficiency and economic benefits. In addition, obtaining ultrafine powder significantly improves the mixing effect, eliminating the need for pretreatment through the addition of additional dispersants or silane coupling modifications, thus simplifying the operation process while ensuring density.

[0203] The above embodiments are exemplary and are intended to illustrate the technical concept and features of the present invention, so that those skilled in the art can understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing refractory parts from ultrafine zirconia nanocomposite powder, characterized in that: Includes the following steps: Mixed ingredients: Add a 15-20% magnesium dihydrogen phosphate solution to the matrix layer premix, with the amount of magnesium dihydrogen phosphate solution added being 10-20% of the total mass of the raw materials. Wet ball mill for 20-30 minutes to form a uniform slurry; dry and sieve to obtain the matrix layer mixture. Add a 15-20% magnesium dihydrogen phosphate solution to the surface layer premix, with the amount of magnesium dihydrogen phosphate solution added being 10-20% of the total mass of the raw materials. Wet ball mill for 20-30 minutes to form a uniform slurry; dry and sieve to obtain the surface layer mixture. Fill the raw materials into the shape: Fill the mold with a matrix layer mixture, which is 90-95% of the total thickness, and then fill with a surface layer mixture, which is 5-10% of the total thickness; after filling, cold isostatic pressing is performed. The formed blank is then sintered. The preform is pre-sintered to remove the binder, then pressure sintered under a protective atmosphere, and then hot isostatic pressing is performed on the sintered preform to further eliminate internal defects and improve the material density. Post-processing of sintered parts: A densified, impermeable zirconia refractory component was prepared by molten salt impregnation and plasma spraying of the sintered part. The raw materials for the ultrafine matrix layer premix include the following components: The raw material for the ultrafine surface layer premix is ​​based on the raw material for the ultrafine matrix layer premix, with the addition of 5% by mass of nano Y2Si2O7 powder.

2. The method for preparing refractory parts from ultrafine zirconia nanocomposite powder according to claim 1, characterized in that: During the raw material filling and molding process, the cold isostatic pressing pressure is 250-350MPa, and the holding time is 2-5 minutes.

3. The method for preparing refractory parts from ultrafine zirconia nanocomposite powder according to claim 1, characterized in that: During the sintering process of the formed green body, the green body is pre-sintered at 780-820℃ for 1-5 hours with a heating rate of 2-4℃ / min to remove the binder; then, it is subjected to gas pressure sintering at 1600-1700℃ for 1-3 hours with nitrogen gas at 8-12MPa and a heating rate of 4-6℃ / min; then, the sintered green body is subjected to hot isostatic pressing at 1400-1600℃ and 120-180MPa in an argon atmosphere for 0.8-1.5 hours with a cooling rate controlled at ≤5℃ / min to further eliminate internal defects and improve the material density.

4. The method for preparing refractory parts from ultrafine zirconia nanocomposite powder according to claim 1, characterized in that: The oxygen content in the atmosphere used for pre-sintering and gas pressure sintering is ≤10ppm.

5. The method for preparing refractory parts from ultrafine zirconia nanocomposite powder according to claim 1, characterized in that: During the post-processing of sintered parts, the sintered parts are immersed in molten borosilicate glass at 1200-1250℃ for 25-40 minutes to fill the surface pores; after immersion, they are naturally cooled and the residual glass phase on the surface is removed.

6. The method for preparing refractory parts from ultrafine zirconia nanocomposite powder according to claim 1, characterized in that: During the post-treatment of sintered parts, after molten salt impregnation, a 30-50μm Al2O3-YAG composite coating is deposited on the surface by plasma spraying.

7. The method for preparing refractory parts from ultrafine zirconia nanocomposite powder according to claim 1, characterized in that: The preparation of ultrafine matrix layer powder premix includes the following steps: According to the formula of matrix layer powder raw materials, zirconium dioxide, single crystal alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano alumina, and nano zirconium oxide are put into a fluidized bed drying equipment for combined drying and mixing treatment. The drying temperature is controlled at 115-125℃ and the hot air flow rate is 1.5-3m / s until the moisture content of the material is ≤0.2%. The material is then transferred to a ball mill for dry grinding treatment. Zirconia grinding balls with a diameter of 2-3mm are used, the ball-to-material ratio is controlled at 3-8:1, the rotation speed is 400-700rpm, and the grinding time is 3-5 hours. The material is then passed through a 1200-mesh sieve to obtain ultrafine matrix layer premix. The preparation of ultrafine surface layer powder premix includes the following steps: According to the formula of the surface layer powder raw materials, zirconium dioxide, single crystal powdered alumina, fused silica powder, boron compounds, rare earth oxides, silicon carbide whiskers, nano alumina, nano zirconium oxide, and Y2Si2O7 are put into a fluidized bed dryer for combined drying and mixing. The drying temperature is controlled at 115-125℃ and the hot air flow rate is 1.5-3m / s until the moisture content of the material is ≤0.2%. The material is then transferred to a ball mill for dry grinding. Zirconia grinding balls with a diameter of 2-3mm are used, the ball-to-material ratio is controlled at 3-8:1, the rotation speed is 400-700rpm, and the grinding time is 3-5 hours. The mixture is then passed through a 1200-mesh sieve to obtain the ultrafine surface layer premix.

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