Preparation method of zirconium oxide toughened aluminum oxide ceramic substrate

Abstract

The invention relates to the technical field of ceramic materials, in particular to a preparation method of a zirconium oxide toughened aluminum oxide ceramic substrate, which comprises the following steps: 1, pretreating a powder material; step 2, preparing slurry; step 3, tape casting; step 4, stamping and forming; and 5, sintering. Before the slurry is prepared, the aluminum oxide powder and the zirconium oxide powder are uniformly mixed and then subjected to plasma treatment, so that the surface activity of the mixed powder of the aluminum oxide and the zirconium oxide is improved, the grain structure of the mixed powder of the aluminum oxide and the zirconium oxide is changed, and the toughening effect of the zirconium oxide on the aluminum oxide ceramic substrate is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic materials, and in particular to a method for preparing a zirconia toughened alumina ceramic substrate. Background Art

[0002] With the rapid advancement of modern science and technology, the demand for high-performance materials is increasing across various fields. In key industries such as electronics, aerospace, and automotive manufacturing, the performance shortcomings of traditional materials, such as metals and polymers like plastics and rubber, are becoming increasingly apparent, making it difficult to meet increasingly demanding operating conditions. Ceramic materials, with their excellent high-temperature resistance, corrosion resistance, and insulation properties, fill the performance gaps between metals and polymers in extreme environments and high-precision, high-reliability applications. They are widely used in aerospace, electronics, automotive, chemical metallurgy, medical and biological fields. Traditional ceramic materials are made from readily available natural minerals, resulting in low production costs. However, due to their loose structure, the presence of a large amount of glass (formed by the fusion of feldspar and clay), and irregular pores (porosity of approximately 10%-30%), these ceramics are relatively low in hardness and brittle. As a new type of ceramic material, alumina ceramic material has the characteristics of high hardness, stable chemical properties and excellent insulation properties. It is the core material of precision devices such as high-frequency circuit substrates and electronic insulators. Compared with traditional ceramic materials, although alumina ceramic material has better toughness than traditional ceramic materials, it still cannot meet the stringent requirements of high-end applications.

[0003] Chinese patent CN116924777A discloses a ceramic slurry, an alumina ceramic substrate, and a preparation method thereof. By employing a combination of micron- and nano-sized alumina, low- and high-molecular-weight polyvinyl butyral, and fluxing agents such as ZrO2, La2O3, SiO2, and LiF, the resulting ceramic strength and warpage yield of the alumina ceramic substrate are improved. However, the raw materials used in this patent are expensive and difficult to preserve, and the addition of La2O3 and LiF can also reduce the sintering performance of the alumina ceramic substrate. Summary of the Invention

[0004] In view of the technical problems of high raw material cost, difficult preservation and poor high-temperature stability of flux in existing toughening methods of alumina ceramic substrates, the present invention provides a preparation method of zirconia toughened alumina ceramic substrates. Before preparing the slurry, the alumina powder and the zirconia powder are evenly mixed and then plasma treated, which increases the surface activity of the mixed powder of alumina and zirconia, changes the grain structure of the mixed powder of alumina and zirconia, and improves the toughening effect of zirconia on the alumina ceramic substrate.

[0005] The technical solutions of the present invention are as follows: A method for preparing a zirconia-toughened alumina ceramic substrate comprises the following steps: Step 1: Pretreatment of powder materials: mixing alumina powder and zirconium oxide powder evenly and then performing plasma treatment to obtain alumina mixed powder; Step 2: preparing the slurry, dissolving the alumina mixed powder obtained in step 1, flux, binder, plasticizer and dispersant in a mixed solvent, and then sequentially performing ball milling, degassing and aging to obtain a slurry; Step 3: tape casting, filtering the slurry obtained in step 2, and then coating it on a PET film to fully spread it, and then heating and drying it to volatilize the mixed solvent in the slurry to obtain a green tape; Step 4: die forming, indenting and stamping the green strip obtained in step 3, and then applying powder, drying and waxing in sequence to obtain a green sheet to be sintered; Step 5: Sintering: sinter the green sheet obtained in step 4 at 1525-1545° C. to obtain a zirconia-toughened alumina ceramic substrate.

[0006] Furthermore, in step 1, the aluminum oxide powder and the zirconium oxide powder are added to a ball mill for ball milling to uniformly mix the aluminum oxide powder and the zirconium oxide powder. The ball milling time is 8-40 hours, and the particle size control range of the ball milling is 1.3-7 μm.

[0007] Furthermore, in step 1, the power of the plasma treatment is 500-1200 W. The present invention uses plasma to treat the evenly mixed alumina powder and zirconia powder. On the one hand, the high-energy particles in the plasma can be used to collide with the alumina powder particles and the zirconia powder particles. The large particles and agglomerates in the alumina powder and the zirconia powder are broken and refined under the action of the plasma to form more uniform particles with smaller particle size. On the other hand, the surface activity of the alumina powder particles and the zirconia powder particles can be synergistically improved, and the active sites on the surfaces of the alumina powder particles and the zirconia powder particles can be significantly increased, thereby more effectively improving the sintering performance and mechanical properties of the ceramic. Plasma treatment can also promote the crystallization and growth of alumina crystals, make the crystal structure of alumina more complete, promote lattice distortion of alumina grains, enhance the chemical reaction activity and sintering activity of alumina powder, stabilize the tetragonal phase of zirconia, ensure the phase change toughening effect of zirconia, and make diffusion, phase change and chemical reaction more likely to occur.

[0008] Furthermore, in the alumina mixed powder, the particle size of alumina is 1.7-4.0 μm, the particle size of zirconium oxide is 0.2-1.6 μm, and the mass ratio of alumina to zirconium oxide is 86-99:1-14, preferably 97:2.

[0009] Furthermore, in step 2, the binder is one or more of polyvinyl butyral (PVB), polyvinyl alcohol, and paraffin, and the binder is preferably polyvinyl butyral (PVB); in step 2, the plasticizer is one or more of dibutyl phthalate (DBP), dimethyl phthalate (DMP), diethyl phthalate (DEP), dioctyl phthalate (DOP), and butyl benzyl phthalate (BBP), and the plasticizer is preferably dibutyl phthalate (DBP); in step 2, the dispersant is one or more of glyceride, fatty acid ester, polyethyleneimine, and polymethacrylic acid, and the dispersant is preferably glyceride.

[0010] Furthermore, in step 2, the flux includes MgO, SiO2, and CaO, and the mass ratio of MgO, SiO2, and CaO in the flux is 0.4-1.6:1-3:0.1-0.7, preferably 1.6:0.9:0.5; and in step 2, the mixed solvent is a mixed solution of toluene and isopropyl alcohol, and the mass ratio of toluene and isopropyl alcohol in the mixed solvent is 3-6:9-13, preferably 5:10.5. The present invention uses an MgO-SiO2-CaO system with a mass ratio of 0.4-1.6:1-3:0.1-0.7 as a flux, while improving the bending resistance and sintering performance of the alumina ceramic substrate, significantly reducing raw material costs. The MgO-SiO2-CaO system has high stability at high temperatures and no toxicity risk.

[0011] Furthermore, in step three, heating and drying are carried out in zone one, zone two and zone three in sequence. During the heating and drying process, the temperature of zone one is 15-55°C, the temperature of zone two is 45-70°C, and the temperature of zone three is 60-110°C.

[0012] Furthermore, in step 3, the thickness of the green tape is 0.2-1.0 mm. During the tape casting process, since the present invention performs plasma treatment on the evenly mixed alumina powder and zirconium oxide powder in step 1, the obtained alumina mixed powder has better dispersibility, and the evenly dispersed powder is conducive to improving the density uniformity of the formed green tape.

[0013] Furthermore, in step 2, the mass of the binder is 5%-9% of the total mass of the alumina mixed powder and the flux, preferably 5%, the mass of the plasticizer is 2%-6% of the total mass of the alumina mixed powder and the flux, preferably 5%, the mass of the dispersant is 0.5%-3% of the total mass of the alumina mixed powder and the flux, preferably 1%, the mass of the mixed solvent is 40%-60% of the total mass of the alumina mixed powder and the flux, preferably 50%, and the mass of the flux is 0.3%-0.8% of the mass of the alumina mixed powder, preferably 0.4%.

[0014] Furthermore, in step 2, the mass ratio of the alumina mixed powder to the flux is 95-97:3-5, preferably 96:4.

[0015] The beneficial effects of the present invention are: The present invention provides a method for preparing a zirconia-toughened alumina ceramic substrate. The method comprises the following steps: mixing alumina powder and zirconia powder uniformly and then subjecting the mixture to a plasma treatment, thereby ensuring that the alumina powder and zirconia powder are uniformly exposed to the plasma. During the plasma treatment of the uniformly mixed alumina powder and zirconia powder, large particles and agglomerates in the alumina powder and zirconia powder are broken and refined under the thermal shock and mechanical force of the instantaneous high-energy particle beam, forming more uniform particles with smaller particle size. The potential on the particle surface also changes, increasing the electrostatic repulsion between the particles, preventing the particles from agglomerating again, and facilitating a more uniform dispersion of the particles in the slurry, thereby more effectively improving the sintering performance. The plasma treatment also causes physical and chemical changes on the surface of the alumina powder and zirconia powder, introducing oxygen-containing functional groups such as -OH on the particle surface, increasing the activity of the alumina particle surface, enhancing the binding force between the alumina particles and other substances, and helping to improve the performance of the substrate; changing the charge distribution on the particle surface, increasing the surface activity of the particles, improving the compatibility of the particles with solvents, fluxes, binders, plasticizers and dispersants, and making the slurry more stable. In the subsequent tape casting step, the evenly dispersed powder is beneficial to improving the density uniformity of the molded green tape.

[0016] In step 4, the present invention performs indentation stamping on the green strip obtained in step 3 by using a blade die, thereby improving the dimensional accuracy, production efficiency and thermal cycle reliability of the zirconia toughened alumina ceramic substrate. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present invention.

[0018] Example 1 A method for preparing a zirconia-toughened alumina ceramic substrate comprises the following steps: Step 1: Pretreatment of the powder materials: Alumina powder and zirconia powder were added to a ball mill and milled until the alumina and zirconia powders were uniformly mixed. The ball milling process lasted 16 hours, and the particle size of the milled powder was controlled within the range of 6.3 μm. The uniformly mixed alumina and zirconia powders were then plasma treated at a power of 500 W to obtain an alumina mixed powder. The alumina particle size in the alumina mixed powder ranged from 1.7 to 4.0 μm, and the zirconia particle size ranged from 0.2 to 1.6 μm. The mass ratio of alumina to zirconia was 97:2.

[0019] Step 2: Preparation of slurry: dissolve the alumina mixed powder obtained in step 1, flux, polyvinyl butyral (PVB) with a molecular weight of 40,000-70,000, dibutyl phthalate (DBP) and glycerol in a mixed solution of toluene and isopropyl alcohol, and then perform ball milling, degassing and aging in sequence to obtain a slurry, and the ball milling time is 20-40 hours; during the degassing process, the degassing pressure is -0.05-0.1MPa, the stirring speed is 10-30Hz, the slurry temperature is 15-35°C, and the slurry viscosity is 1000-7000Cps; during the aging process, the aging time is 5-24h, the stirring speed is 0-3Hz, the slurry temperature is controlled at 25-30°C, and the slurry viscosity is controlled at 1000-7000Cps. The flux is composed of MgO, SiO2, and CaO. The mass ratio of MgO, SiO2, and CaO in the flux is 1.6:0.9:0.5. The mass of polyvinyl butyral (PVB) is 5% of the total mass of the alumina mixed powder and flux, the mass of dibutyl phthalate (DBP) is 5%, and the mass of glycerol ester is 1%. In the mixed solvent, the mass ratio of toluene to isopropyl alcohol is 5:10.5. The mass of the mixed solvent is 50% of the total mass of the alumina mixed powder and flux. The mass ratio of the alumina mixed powder to flux is 96:4.

[0020] Step 3: Tape casting: The slurry obtained in step 2 is filtered through a filter. The filtered slurry is then evenly applied to a PET film through a hopper. The thickness of the slurry applied to the PET film is adjusted using a scraper. The slurry is then heated and dried to evaporate the mixed solvent in the slurry, resulting in a green tape with a thickness of 0.2-1.0 mm. During the heating and drying process, the temperature in zone 1 is 15-55°C, the temperature in zone 2 is 45-70°C, and the temperature in zone 3 is 60-110°C.

[0021] Step 4: Die Forming: The green sheet obtained in Step 3 is stamped and formed using a blade die. The sheet is then powder coated, dried again, and waxed to produce a green sheet ready for sintering. The lower left corner of the green sheet is prepared with a C = 1.50 identification angle, and the other three corners are chamfered with a C = 0.75.

[0022] Step 5: Sintering. The green sheet to be sintered obtained in step 4 is placed in a main sintering furnace at 1530°C for sintering to obtain a highly versatile, large-scale ceramic substrate. During the sintering process, migration densification and recrystallization will occur, causing the particles to bond and produce a certain strength. Use a high-pressure sandblasting machine to sandblast the surface of the ceramic substrate, then clean and dry it to obtain a zirconia-toughened alumina ceramic substrate. The zirconia-toughened alumina ceramic substrate has a length of 190±0.04mm, a width of 138±0.04mm, and a thickness of 0.38±0.04mm. Among them, the sandblasting pressure is 180±10kPa, the first and second level cleaning pressures are 10-150kPa, and the drying temperature is 50±10°C.

[0023] Step 6: The zirconia-toughened alumina ceramic substrate obtained in Step 5 is subjected to a warpage test. Under its own weight, the zirconia-toughened alumina ceramic substrate is passed through a marble plate with a certain gap at a 45° angle. A passing test indicates acceptable surface flatness. Zirconia-toughened alumina ceramic substrates that fail the warpage test are softened at 1400°C and then stacked in a flattening furnace using their own gravity to improve warpage.

[0024] Step 7: Product inspection, using automatic appearance inspection equipment to form surface defect traces through model learning and training.

[0025] Example 2 A method for preparing a zirconia-toughened alumina ceramic substrate comprises the following steps: Step 1: Pretreatment of the powder materials: Alumina powder and zirconia powder were added to a ball mill and milled until the alumina and zirconia powders were uniformly mixed. The milling process lasted 12 hours, and the particle size control range was 6.8 μm. The mixed alumina and zirconia powders were then plasma treated at a power of 600 W to obtain an alumina mixed powder. The alumina particle size in the alumina mixed powder was 2.6 ± 0.2 μm, and the zirconia particle size was 0.2-1.6 μm.

[0026] Step 2: Prepare the slurry. The alumina powder mixture obtained in Step 1, flux, polyvinyl butyral (PVB), dibutyl phthalate (DBP), and glycerol are dissolved in a mixture of toluene and isopropyl alcohol. The mixture is then ball-milled, degassed, and aged to obtain a slurry. The milling time is 26 hours. The degassed pressure is -0.08 MPa, the stirring speed is 19 Hz, the slurry temperature is 27°C, and the slurry viscosity is 4800 cps. The aging time is 24 hours, the stirring speed is 1.6 Hz, the slurry temperature is controlled at 28°C, and the slurry viscosity is controlled at 5400 cps. The flux is MgO, SiO2, and CaO. The mass ratio of MgO, SiO2, and CaO in the flux is 1.6:0.9:0.5. The mass of polyvinyl butyral (PVB) is 5% of the total mass of the alumina powder mixture and flux, the mass of dibutyl phthalate (DBP) is 5% of the total mass of the alumina powder mixture and flux, and the mass of glycerol is 1% of the total mass of the alumina powder mixture and flux. The mass ratio of toluene to isopropyl alcohol in the mixed solvent is 5:10.5. The mass of the mixed solvent is 50% of the total mass of the alumina powder mixture and flux. The mass ratio of the alumina powder mixture to the flux is 96:4.

[0027] Step 3: tape casting, use a filter to filter the slurry obtained in step 2, then evenly apply the filtered slurry on the PET film through a hopper and spread it fully, and use a scraper to adjust the thickness of the slurry coated on the PET film, then heat and dry it to evaporate the mixed solvent in the slurry to obtain a green strip with a thickness of 0.2-1.0 mm.

[0028] Step 4: Die Forming: The green sheet obtained in Step 3 is stamped and formed using a blade die. The sheet is then powder coated, dried again, and waxed to produce a green sheet ready for sintering. The lower left corner of the green sheet is prepared with a C = 1.50 identification angle, and the other three corners are chamfered with a C = 0.75.

[0029] Step 5: Sintering: The green sheet obtained in Step 4 is placed in a main furnace at 1530°C for sintering, resulting in a highly versatile, large-scale ceramic substrate. During the sintering process, migration, densification, and recrystallization occur, bonding the particles and imparting a certain strength. The surface of the ceramic substrate is sandblasted using a high-pressure sandblaster, followed by cleaning and drying to obtain a zirconia-toughened alumina ceramic substrate.

[0030] Step 6: The zirconia-toughened alumina ceramic substrate obtained in Step 5 is subjected to a warpage test. Under its own weight, the zirconia-toughened alumina ceramic substrate is passed through a marble plate with a certain gap at a 45° angle. A passing test indicates acceptable surface flatness. Zirconia-toughened alumina ceramic substrates that fail the warpage test are softened at 1400°C and then stacked in a flattening furnace using their own gravity to improve warpage.

[0031] Step 7: Product inspection, using automatic appearance inspection equipment to form surface defect traces through model learning and training.

[0032] Example 3 A method for preparing a zirconia-toughened alumina ceramic substrate comprises the following steps: Step 1: Pretreatment of the powder materials: Alumina powder and zirconia powder were added to a ball mill and milled until the alumina and zirconia powders were uniformly mixed. The milling process lasted 11 hours, and the particle size control range was 6.4 μm. The uniformly mixed alumina and zirconia powders were then plasma treated at a power of 800 W to obtain an alumina mixed powder. The alumina particle size in the alumina mixed powder was 2.1 ± 0.2 μm, and the zirconia particle size was 0.2-1.6 μm.

[0033] Step 2: Prepare the slurry. The alumina powder mixture obtained in Step 1, flux, polyvinyl butyral (PVB), dibutyl phthalate (DBP), and glycerol ester are dissolved in a mixture of toluene and isopropyl alcohol. The mixture is then ball-milled, degassed, and aged to obtain a slurry. The ball-milling time is 25 hours. The degassed pressure is -0.09 MPa, the stirring speed is 12 Hz, the slurry temperature is 31°C, and the slurry viscosity is 5230 cps. The aging time is 22 hours, the stirring speed is 2.2 Hz, the slurry temperature is controlled at 28°C, and the slurry viscosity is controlled at 5010 cps. The flux is MgO, SiO2, and CaO. The mass ratio of MgO, SiO2, and CaO in the flux is 1.6:0.9:0.5. The mass of polyvinyl butyral (PVB) is 5% of the total mass of the alumina powder mixture and flux, the mass of dibutyl phthalate (DBP) is 5% of the total mass of the alumina powder mixture and flux, and the mass of glycerol is 1% of the total mass of the alumina powder mixture and flux. The mass ratio of toluene to isopropyl alcohol in the mixed solvent is 5:10.5. The mass of the mixed solvent is 50% of the total mass of the alumina powder mixture and flux. The mass ratio of the alumina powder mixture to the flux is 96:4.

[0034] Step 3: tape casting, use a filter to filter the slurry obtained in step 2, then evenly apply the filtered slurry on the PET film through a hopper and spread it fully, and use a scraper to adjust the thickness of the slurry coated on the PET film, then heat and dry it to evaporate the mixed solvent in the slurry to obtain a green strip with a thickness of 0.2-1.0 mm.

[0035] Step 4: Die Forming: The green sheet obtained in Step 3 is stamped and formed using a blade die. The sheet is then powder coated, dried again, and waxed to produce a green sheet ready for sintering. The lower left corner of the green sheet is prepared with a C = 1.50 identification angle, and the other three corners are chamfered with a C = 0.75.

[0036] Step 5: Sintering: The green sheet obtained in Step 4 is placed in a main furnace at 1530°C for sintering, resulting in a highly versatile, large-scale ceramic substrate. During the sintering process, migration, densification, and recrystallization occur, bonding the particles and imparting a certain strength. The surface of the ceramic substrate is sandblasted using a high-pressure sandblaster, followed by cleaning and drying to obtain a zirconia-toughened alumina ceramic substrate.

[0037] Step 6: The zirconia-toughened alumina ceramic substrate obtained in Step 5 is subjected to a warpage test. Under its own weight, the zirconia-toughened alumina ceramic substrate is passed through a marble plate with a certain gap at a 45° angle. A passing test indicates acceptable surface flatness. Zirconia-toughened alumina ceramic substrates that fail the warpage test are softened at 1400°C and then stacked in a flattening furnace using their own gravity to improve warpage.

[0038] Step 7: Product inspection, using automatic appearance inspection equipment to form surface defect traces through model learning and training.

[0039] Example 4 A method for preparing a zirconia-toughened alumina ceramic substrate comprises the following steps: Step 1: Pretreatment of the powder materials: Alumina powder and zirconia powder were added to a ball mill and milled until the alumina and zirconia powders were uniformly mixed. The milling process lasted for 9 hours, and the particle size control range was 6.7 μm. The uniformly mixed alumina and zirconia powders were then plasma treated at a power of 1000 W to obtain an alumina mixed powder. The alumina particle size in the alumina mixed powder was 1.9 ± 0.2 μm, and the zirconia particle size was 0.2-1.6 μm.

[0040] Step 2: Prepare the slurry. The alumina powder mixture obtained in Step 1, flux, polyvinyl butyral (PVB), dibutyl phthalate (DBP), and glycerol ester are dissolved in a mixture of toluene and isopropyl alcohol. The mixture is then ball-milled, degassed, and aged to obtain a slurry. The ball-milling time is 27 hours. The degassed pressure is -0.06 MPa, the stirring speed is 17 Hz, the slurry temperature is 31°C, and the slurry viscosity is 6000 cps. The aging time is 18 hours, the stirring speed is 1.9 Hz, the slurry temperature is controlled at 28°C, and the slurry viscosity is controlled at 5900 cps. The flux is MgO, SiO2, and CaO. The mass ratio of MgO, SiO2, and CaO in the flux is 1.6:0.9:0.5. The mass of polyvinyl butyral (PVB) is 5% of the total mass of the alumina powder mixture and flux, the mass of dibutyl phthalate (DBP) is 5% of the total mass of the alumina powder mixture and flux, and the mass of glycerol is 1% of the total mass of the alumina powder mixture and flux. The mass ratio of toluene to isopropyl alcohol in the mixed solvent is 5:10.5. The mass of the mixed solvent is 50% of the total mass of the alumina powder mixture and flux. The mass ratio of the alumina powder mixture to the flux is 96:4.

[0041] Step 3: tape casting, use a filter to filter the slurry obtained in step 2, then evenly apply the filtered slurry on the PET film through a hopper and spread it fully, and use a scraper to adjust the thickness of the slurry coated on the PET film, and then heat and dry it to evaporate the mixed solvent in the slurry to obtain a green strip with a thickness of 0.2-1.0 mm.

[0042] Step 4: Die Forming: The green sheet obtained in Step 3 is stamped and formed using a blade die. The sheet is then powder coated, dried again, and waxed to produce a green sheet ready for sintering. The lower left corner of the green sheet is prepared with a C = 1.50 identification angle, and the other three corners are chamfered with a C = 0.75.

[0043] Step 5: Sintering. Place the green sheet obtained in step 4 in a main sintering furnace at 1530°C for sintering to obtain a highly versatile, large-scale ceramic substrate. During the sintering process, migration, densification, and recrystallization will occur, causing the particles to bond and produce a certain strength. Use a high-pressure sandblasting machine to sandblast the surface of the ceramic substrate, then clean and dry it to obtain a zirconia-toughened alumina ceramic substrate. Step 6: The zirconia-toughened alumina ceramic substrate obtained in Step 5 is warped against a marble slab with a certain gap. If it passes the warpage test, it indicates that the surface flatness is acceptable. The zirconia-toughened alumina ceramic substrate that fails the warpage test is softened at 1400°C and stacked in a flattening furnace using its own gravity to improve the warpage.

[0044] Step 7: Product inspection, using automatic appearance inspection equipment to form surface defect traces through model learning and training.

[0045] Example 5 A method for preparing a zirconia-toughened alumina ceramic substrate comprises the following steps: Step 1: Pretreatment of the powder materials: Alumina powder and zirconia powder were added to a ball mill and milled until the alumina and zirconia powders were uniformly mixed. The milling process lasted 13 hours, and the particle size control range was 6.7 μm. The uniformly mixed alumina and zirconia powders were then plasma treated at a power of 1100 W to obtain an alumina mixed powder. The alumina particle size in the alumina mixed powder was 1.8 ± 0.2 μm, and the zirconia particle size was 0.2-1.6 μm.

[0046] Step 2: Prepare the slurry. The alumina powder mixture obtained in Step 1, flux, polyvinyl butyral (PVB), dibutyl phthalate (DBP), and glycerol ester are dissolved in a mixture of toluene and isopropyl alcohol. The mixture is then ball-milled, degassed, and aged to obtain a slurry. The ball-milling time is 26 hours. During the degasking process, the degassing pressure is -0.08 MPa, the stirring speed is 17 Hz, the slurry temperature is 28°C, and the slurry viscosity is 4800 cps. During the aging process, the aging time is 18 hours, the stirring speed is 1.9 Hz, the slurry temperature is controlled at 28°C, and the slurry viscosity is controlled at 5900 cps. The flux is MgO, SiO2, and CaO. The mass ratio of MgO, SiO2, and CaO in the flux is 1.6:0.9:0.5. The mass of polyvinyl butyral (PVB) is 5% of the total mass of the alumina powder mixture and flux, the mass of dibutyl phthalate (DBP) is 5% of the total mass of the alumina powder mixture and flux, and the mass of glycerol is 1% of the total mass of the alumina powder mixture and flux. The mass ratio of toluene to isopropyl alcohol in the mixed solvent is 5:10.5. The mass of the mixed solvent is 50% of the total mass of the alumina powder mixture and flux. The mass ratio of the alumina powder mixture to the flux is 96:4.

[0047] Step 3: tape casting, use a filter to filter the slurry obtained in step 2, then evenly apply the filtered slurry on the PET film through a hopper and spread it fully, and use a scraper to adjust the thickness of the slurry coated on the PET film, then heat and dry it to evaporate the mixed solvent in the slurry to obtain a green strip with a thickness of 0.2-1.0 mm.

[0048] Step 4: Die Forming: The green sheet obtained in Step 3 is stamped and formed using a blade die. The sheet is then powder coated, dried again, and waxed to produce a green sheet ready for sintering. The lower left corner of the green sheet is prepared with a C = 1.50 identification angle, and the other three corners are chamfered with a C = 0.75.

[0049] Step 5: Sintering: The green sheet obtained in Step 4 is placed in a main furnace at 1530°C for sintering, resulting in a highly versatile, large-scale ceramic substrate. During the sintering process, migration, densification, and recrystallization occur, bonding the particles and imparting a certain strength. The surface of the ceramic substrate is sandblasted using a high-pressure sandblaster, followed by cleaning and drying to obtain a zirconia-toughened alumina ceramic substrate.

[0050] Step 6: The zirconia-toughened alumina ceramic substrate obtained in Step 5 is subjected to a warpage test. Under its own weight, the zirconia-toughened alumina ceramic substrate is passed through a marble plate with a certain gap at a 45° angle. A passing test indicates acceptable surface flatness. Zirconia-toughened alumina ceramic substrates that fail the warpage test are softened at 1400°C and then stacked in a flattening furnace using their own gravity to improve warpage.

[0051] Step 7: Product inspection, using automatic appearance inspection equipment to form surface defect traces through model learning and training.

[0052] Example 6 A method for preparing a zirconia-toughened alumina ceramic substrate comprises the following steps: Step 1: Pretreatment of the powder materials: Alumina powder and zirconia powder were added to a ball mill and ball-milled to uniformly mix the two powders. The ball milling process lasted for 8 hours, and the particle size control range was 6.7 μm. The mixed alumina and zirconia powders were then plasma-treated at a power of 1200 W to obtain an alumina mixed powder. The alumina particle size in the alumina mixed powder was 1.8 ± 0.2 μm, and the zirconia particle size was 0.2-1.6 μm.

[0053] Step 2: Prepare the slurry. The alumina powder mixture obtained in Step 1, flux, polyvinyl butyral (PVB), dibutyl phthalate (DBP), and glycerol ester are dissolved in a mixture of toluene and isopropyl alcohol. The mixture is then ball-milled, degassed, and aged to obtain a slurry. The milling time is 26 hours. The degassed pressure is -0.06 MPa, the stirring speed is 15 Hz, the slurry temperature is 32°C, and the slurry viscosity is 5900 cps. The aging time is 23 hours, the stirring speed is 2.6 Hz, the slurry temperature is controlled at 28°C, and the slurry viscosity is controlled at 6100 cps. The flux is MgO, SiO2, and CaO. The mass ratio of MgO, SiO2, and CaO in the flux is 1.6:0.9:0.5. The mass of polyvinyl butyral (PVB) is 5% of the total mass of the alumina powder mixture and flux, the mass of dibutyl phthalate (DBP) is 5% of the total mass of the alumina powder mixture and flux, and the mass of glycerol is 1% of the total mass of the alumina powder mixture and flux. The mass ratio of toluene to isopropyl alcohol in the mixed solvent is 5:10.5. The mass of the mixed solvent is 50% of the total mass of the alumina powder mixture and flux. The mass ratio of the alumina powder mixture to the flux is 96:4.

[0054] Step 3: tape casting, use a filter to filter the slurry obtained in step 2, then evenly apply the filtered slurry on the PET film through a hopper and spread it fully, and use a scraper to adjust the thickness of the slurry coated on the PET film, then heat and dry it to evaporate the mixed solvent in the slurry to obtain a green strip with a thickness of 0.2-1.0 mm.

[0055] Step 4: Die Forming: The green sheet obtained in Step 3 is stamped and formed using a blade die. The sheet is then powder coated, dried again, and waxed to produce a green sheet ready for sintering. The lower left corner of the green sheet is prepared with a C = 1.50 identification angle, and the other three corners are chamfered with a C = 0.75.

[0056] Step 5: Sintering: The green sheet obtained in Step 4 is placed in a main furnace at 1530°C for sintering, resulting in a highly versatile, large-scale ceramic substrate. During the sintering process, migration, densification, and recrystallization occur, bonding the particles and imparting a certain strength. The surface of the ceramic substrate is sandblasted using a high-pressure sandblaster, followed by cleaning and drying to obtain a zirconia-toughened alumina ceramic substrate.

[0057] Step 6: The zirconia-toughened alumina ceramic substrate obtained in Step 5 is subjected to a warpage test. Under its own weight, the zirconia-toughened alumina ceramic substrate is passed through a marble plate with a certain gap at a 45° angle. A passing test indicates acceptable surface flatness. Zirconia-toughened alumina ceramic substrates that fail the warpage test are softened at 1400°C and then stacked in a flattening furnace using their own gravity to improve warpage.

[0058] Step 7: Product inspection, using automatic appearance inspection equipment to form surface defect traces through model learning and training.

[0059] Example 7 A method for preparing a zirconia-toughened alumina ceramic substrate comprises the following steps: Step 1: Pretreatment of the powder materials: Alumina powder and zirconia powder were added to a ball mill and milled until the alumina and zirconia powders were uniformly mixed. The milling process lasted for 8 hours, and the particle size control range was 6.7 μm. The uniformly mixed alumina and zirconia powders were then plasma treated at a power of 1100 W to obtain an alumina mixed powder. The alumina particle size in the alumina mixed powder was 1.8 ± 0.2 μm, and the zirconia particle size was 0.2-1.6 μm.

[0060] Step 2: Prepare the slurry. The alumina powder mixture obtained in Step 1, flux, polyvinyl butyral (PVB), dibutyl phthalate (DBP), and glycerol ester are dissolved in a mixture of toluene and isopropyl alcohol. The mixture is then ball-milled, degassed, and aged to obtain a slurry. The milling time is 25 hours. The degassed pressure is -0.08 MPa, the stirring speed is 4 Hz, the slurry temperature is 33°C, and the slurry viscosity is 6100 cps. The aging time is 23 hours, the stirring speed is 2.6 Hz, the slurry temperature is controlled at 27°C, and the slurry viscosity is controlled at 5900 cps. The flux is MgO, SiO2, and CaO. The mass ratio of MgO, SiO2, and CaO in the flux is 1.6:0.9:0.5. The mass of polyvinyl butyral (PVB) is 5% of the total mass of the alumina powder mixture and flux, the mass of dibutyl phthalate (DBP) is 5% of the total mass of the alumina powder mixture and flux, and the mass of glycerol is 1% of the total mass of the alumina powder mixture and flux. The mass ratio of toluene to isopropyl alcohol in the mixed solvent is 5:10.5. The mass of the mixed solvent is 50% of the total mass of the alumina powder mixture and flux. The mass ratio of the alumina powder mixture to the flux is 96:4.

[0061] Step 3: tape casting, use a filter to filter the slurry obtained in step 2, then evenly apply the filtered slurry on the PET film through a hopper and spread it fully, and use a scraper to adjust the thickness of the slurry coated on the PET film, then heat and dry it to evaporate the mixed solvent in the slurry to obtain a green strip with a thickness of 0.2-1.0 mm.

[0062] Step 4: Die Forming: The green sheet obtained in Step 3 is stamped and formed using a blade die. The sheet is then powder coated, dried again, and waxed to produce a green sheet ready for sintering. The lower left corner of the green sheet is prepared with a C = 1.50 identification angle, and the other three corners are chamfered with a C = 0.75.

[0063] Step 5: Sintering: The green sheet obtained in Step 4 is placed in a main furnace at 1545°C for sintering, resulting in a highly versatile, large-scale ceramic substrate. During the sintering process, migration, densification, and recrystallization occur, bonding the particles and imparting a certain strength. The surface of the ceramic substrate is sandblasted using a high-pressure sandblaster, followed by cleaning and drying to obtain a zirconia-toughened alumina ceramic substrate.

[0064] Step 6: The zirconia-toughened alumina ceramic substrate obtained in Step 5 is subjected to a warpage test. Under its own weight, the zirconia-toughened alumina ceramic substrate is passed through a marble plate with a certain gap at a 45° angle. A passing test indicates acceptable surface flatness. Zirconia-toughened alumina ceramic substrates that fail the warpage test are softened at 1400°C and then stacked in a flattening furnace using their own gravity to improve warpage.

[0065] Step 7: Product inspection, using automatic appearance inspection equipment to form surface defect traces through model learning and training.

[0066] Example 8 A method for preparing a zirconia-toughened alumina ceramic substrate comprises the following steps: Step 1: Pretreatment of the powder materials: Alumina powder and zirconia powder were added to a ball mill and milled until the alumina and zirconia powders were uniformly mixed. The milling process lasted 12 hours, and the particle size control range was 6.5 μm. The mixed alumina and zirconia powders were then plasma treated at a power of 1100 W to obtain an alumina mixed powder. The alumina particle size in the alumina mixed powder was 1.8 ± 0.2 μm, and the zirconia particle size was 0.2-1.6 μm.

[0067] Step 2: Prepare the slurry. The alumina powder mixture obtained in Step 1, flux, polyvinyl butyral (PVB), dibutyl phthalate (DBP), and glycerol are dissolved in a mixture of toluene and isopropyl alcohol. The mixture is then ball-milled, degassed, and aged to obtain a slurry. The milling time is 26 hours. The degassed pressure is -0.08 MPa, the stirring speed is 14 Hz, the slurry temperature is 33°C, and the slurry viscosity is 5700 cps. The aging time is 23 hours, the stirring speed is 2.6 Hz, the slurry temperature is controlled at 27°C, and the slurry viscosity is controlled at 5200 cps. The flux is MgO, SiO2, and CaO. The mass ratio of MgO, SiO2, and CaO in the flux is 1.6:0.9:0.5. The mass of polyvinyl butyral (PVB) is 5% of the total mass of the alumina powder mixture and flux, the mass of dibutyl phthalate (DBP) is 5% of the total mass of the alumina powder mixture and flux, and the mass of glycerol is 1% of the total mass of the alumina powder mixture and flux. The mass ratio of toluene to isopropyl alcohol in the mixed solvent is 5:10.5. The mass of the mixed solvent is 50% of the total mass of the alumina powder mixture and flux. The mass ratio of the alumina powder mixture to the flux is 96:4.

[0068] Step 3: tape casting, use a filter to filter the slurry obtained in step 2, then evenly apply the filtered slurry on the PET film through a hopper and spread it fully, and use a scraper to adjust the thickness of the slurry coated on the PET film, and then heat and dry it to evaporate the mixed solvent in the slurry to obtain a green strip with a thickness of 0.2-1.0 mm.

[0069] Step 4: Die Forming: The green sheet obtained in Step 3 is stamped and formed using a blade die. The sheet is then powder coated, dried again, and waxed to produce a green sheet ready for sintering. The lower left corner of the green sheet is prepared with a C = 1.50 identification angle, and the other three corners are chamfered with a C = 0.75.

[0070] Step 5: Sintering. Place the green sheet obtained in step 4 in the main sintering furnace at 1540°C for sintering to obtain a highly versatile, large-scale ceramic substrate. During the sintering process, migration, densification and recrystallization will occur, causing the particles to bond and produce a certain strength. Use a high-pressure sandblasting machine to sandblast the surface of the ceramic substrate, then clean and dry it to obtain a zirconia-toughened alumina ceramic substrate. Step 6: The zirconia-toughened alumina ceramic substrate obtained in Step 5 is subjected to a warpage test. Under its own weight, the zirconia-toughened alumina ceramic substrate is passed through a marble plate with a certain gap at a 45° angle. A passing test indicates acceptable surface flatness. Zirconia-toughened alumina ceramic substrates that fail the warpage test are softened at 1400°C and then stacked in a flattening furnace using their own gravity to improve warpage.

[0071] Step 7: Product inspection, using automatic appearance inspection equipment to form surface defect traces through model learning and training.

[0072] Example 9 A method for preparing a zirconia-toughened alumina ceramic substrate comprises the following steps: Step 1: Pretreatment of the powder materials: Alumina powder and zirconia powder were added to a ball mill and ball-milled to uniformly mix the two powders. The milling process lasted 12 hours, and the particle size control range was 6.7 μm. The mixed alumina and zirconia powders were then plasma-treated at a power of 1100 W to produce an alumina mixed powder. The alumina particle size in the alumina mixed powder was 1.8 ± 0.2 μm, and the zirconia particle size was 0.2-1.6 μm.

[0073] Step 2: Prepare the slurry. The alumina powder mixture obtained in Step 1, flux, polyvinyl butyral (PVB), dibutyl phthalate (DBP), and glycerol ester are dissolved in a mixture of toluene and isopropyl alcohol. The mixture is then ball-milled, degassed, and aged to obtain a slurry. The ball-milling time is 26 hours. The degassed pressure is -0.08 MPa, the stirring speed is 14 Hz, the slurry temperature is 33°C, and the slurry viscosity is 5700 cps. The aging time is 23 hours, the stirring speed is 2.6 Hz, the slurry temperature is controlled at 27°C, and the slurry viscosity is controlled at 5200 cps. The flux is MgO, SiO2, and CaO. The mass ratio of MgO, SiO2, and CaO in the flux is 1.6:0.9:0.5. The mass of polyvinyl butyral (PVB) is 5% of the total mass of the alumina powder mixture and flux, the mass of dibutyl phthalate (DBP) is 5% of the total mass of the alumina powder mixture and flux, and the mass of glycerol is 1% of the total mass of the alumina powder mixture and flux. The mass ratio of toluene to isopropyl alcohol in the mixed solvent is 5:10.5. The mass of the mixed solvent is 50% of the total mass of the alumina powder mixture and flux. The mass ratio of the alumina powder mixture to the flux is 96:4.

[0074] Step 3: tape casting, use a filter to filter the slurry obtained in step 2, then evenly apply the filtered slurry on the PET film through a hopper and spread it fully, and use a scraper to adjust the thickness of the slurry coated on the PET film, and then heat and dry it to evaporate the mixed solvent in the slurry to obtain a green strip with a thickness of 0.2-1.0 mm.

[0075] Step 4: Die Forming: The green sheet obtained in Step 3 is stamped and formed using a blade die. The sheet is then powder coated, dried again, and waxed to produce a green sheet ready for sintering. The lower left corner of the green sheet is prepared with a C = 1.50 identification angle, and the other three corners are chamfered with a C = 0.75.

[0076] Step 5: Sintering: The green sheet obtained in Step 4 is placed in a main furnace at 1535°C for sintering, resulting in a highly versatile, large-scale ceramic substrate. During the sintering process, migration, densification, and recrystallization occur, bonding the particles and imparting a certain strength. The surface of the ceramic substrate is sandblasted using a high-pressure sandblaster, followed by cleaning and drying to obtain a zirconia-toughened alumina ceramic substrate.

[0077] Step 6: The zirconia-toughened alumina ceramic substrate obtained in Step 5 is subjected to a warpage test. Under its own weight, the zirconia-toughened alumina ceramic substrate is passed through a marble plate with a certain gap at a 45° angle. A passing test indicates acceptable surface flatness. Zirconia-toughened alumina ceramic substrates that fail the warpage test are softened at 1400°C and then stacked in a flattening furnace using their own gravity to improve warpage.

[0078] Step 7: Product inspection, using automatic appearance inspection equipment to form surface defect traces through model learning and training.

[0079] Comparative Example 1 Comparative Example 1 differs only in step 1: pretreatment of the powder materials. Alumina powder and zirconia powder were added to a ball mill and milled until uniformly mixed. The milling process lasted 36 hours, with a particle size controlled within the range of 3.2-4.6 μm, to produce an alumina mixed powder. The alumina particle size in the alumina mixed powder was 3.0 ± 0.2 μm, and the zirconia particle size was 0.2-1.6 μm.

[0080] Comparative Example 2 Comparative Example 2 differs from Example 1 only in step 1: pretreatment of the powder materials. Alumina powder and zirconia powder were added to a ball mill and milled until the alumina and zirconia powders were uniformly mixed. The milling process lasted 39 hours, and the particle size was controlled within the range of 2.9-5.3 μm, resulting in an alumina mixed powder. The alumina particle size in the alumina mixed powder was 2.7 ± 0.2 μm, and the zirconia particle size was 0.2-1.6 μm.

[0081] Comparative Example 3 Comparative Example 3 differs only from Example 1 in Step 5: Sintering. The green sheet obtained in Step 4 is placed in a main furnace at 1545°C for sintering, resulting in a highly versatile, large-scale ceramic substrate. During the sintering process, migration densification and recrystallization occur, bonding the particles and imparting a certain strength. The surface of the ceramic substrate is sandblasted using a high-pressure sandblaster, followed by cleaning and drying, to obtain a zirconia-toughened alumina ceramic substrate.

[0082] Comparative Example 4 Comparative Example 4 differs only from Example 1 in Step 5: Sintering. The green sheet obtained in Step 4 is placed in a main furnace at 1540°C for sintering, resulting in a highly versatile, large-scale ceramic substrate. During the sintering process, migration densification and recrystallization occur, bonding the particles and imparting a certain strength. The surface of the ceramic substrate is sandblasted using a high-pressure sandblaster, followed by cleaning and drying, to obtain a zirconia-toughened alumina ceramic substrate.

[0083] Comparative Example 5 Comparative Example 5 differs from Example 1 only in step 5: sintering. The green sheet obtained in step 4 is placed in a main furnace at 1535°C for sintering, resulting in a highly versatile, large-scale ceramic substrate. During the sintering process, migration densification and recrystallization occur, bonding the particles and imparting a certain strength. The surface of the ceramic substrate is sandblasted using a high-pressure sandblaster, followed by cleaning and drying, to obtain a zirconia-toughened alumina ceramic substrate.

[0084] The performance of the zirconia-toughened alumina ceramic substrate products obtained in step 7 of Examples 1-9 and Comparative Examples 1-5 was tested. The test method is described as follows: 1. Surface roughness test The surface roughness of the zirconia toughened alumina ceramic substrate product was tested using the stylus probing method. The test stylus was gently scratched across the surface of the zirconia toughened alumina ceramic substrate product to obtain the Ra value of the surface roughness of the zirconia toughened alumina ceramic substrate product (at least three samples were selected for each condition, and 3 points were selected at different positions of the samples for testing, and the average value of the test results was taken).

[0085] 2. Density test The density of zirconia toughened alumina ceramic substrate products was tested using the drainage method (at least five samples were selected for testing under each condition, and the average value of the test results was taken).

[0086] 3. Bending strength test The flexural strength of the zirconia toughened alumina ceramic substrate product was tested using a universal testing machine (at least three samples were selected for testing under each condition, and the average value of the test results was taken. The size of the test sample was 30×20 mm, the test span was 25 mm, and the descending speed was 0.5 mm / min).

[0087] The performance test results of the alumina particle size, sintering temperature, surface roughness, flexural strength and density of the zirconia-toughened alumina ceramic substrate product obtained in step 7 in Examples 1-9 and Comparative Examples 1-5 are shown in Table 1.

[0088] Table 1 Some process parameters and performance test results of Examples 1-9 and Comparative Examples 1-5

[0089] As can be seen from Table 1, the particle size of the aluminum oxide after plasma treatment is finer, and the strength of the substrate after plasma treatment is higher at the same sintering temperature, indicating that the preparation method provided by the present invention can significantly improve the mechanical properties of the substrate and reduce the sintering performance.

[0090] Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and substance of the present invention, persons of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any changes or substitutions that can be readily conceived by persons skilled in the art within the technical scope disclosed in the present invention shall be within the scope of protection of the present invention.

Claims

1. A method for preparing a zirconia toughened alumina ceramic substrate, characterized in that: The steps include: Step 1: Pretreatment of powder materials: mixing alumina powder and zirconium oxide powder evenly and then performing plasma treatment to obtain alumina mixed powder; Step 2: preparing the slurry, dissolving the alumina mixed powder obtained in step 1, flux, binder, plasticizer and dispersant in a mixed solvent, and then sequentially performing ball milling, degassing and aging to obtain a slurry; Step 3: tape casting, filtering the slurry obtained in step 2, and then coating it on a PET film to fully spread it, and then heating and drying it to volatilize the mixed solvent in the slurry to obtain a green tape; Step 4: die forming, indenting and stamping the green strip obtained in step 3, and then applying powder, drying and waxing in sequence to obtain a green sheet to be sintered; Step 5: Sintering: sinter the green sheet obtained in step 4 at 1525-1545° C. to obtain a zirconia-toughened alumina ceramic substrate.

2. The method for preparing a zirconia toughened alumina ceramic substrate according to claim 1, wherein: In step 1, the aluminum oxide powder and the zirconium oxide powder are added into a ball mill and ball milled to mix the aluminum oxide powder and the zirconium oxide powder uniformly.

3. The method for preparing a zirconia toughened alumina ceramic substrate according to claim 1 or 2, characterized in that: In step 1, the power of the plasma treatment is 500-1200W.

4. The method for preparing a zirconia toughened alumina ceramic substrate according to claim 3, wherein: In the alumina mixed powder, the particle size of the alumina is 1.7-4.0 μm, the particle size of the zirconium oxide is 0.2-1.6 μm, and the mass ratio of the alumina to the zirconium oxide is 86-99:1-14.

5. The method for preparing a zirconia toughened alumina ceramic substrate according to claim 1, wherein: In step 2, the binder is one or more of polyvinyl butyral, polyvinyl alcohol, and paraffin; in step 2, the plasticizer is one or more of dibutyl phthalate, dimethyl phthalate, diethyl phthalate, dioctyl phthalate, and butyl benzyl phthalate; in step 2, the dispersant is one or more of glyceride, fatty acid ester, polyethyleneimine, and polymethacrylic acid.

6. The method for preparing a zirconia toughened alumina ceramic substrate according to claim 1, wherein: In step 2, the flux includes MgO, SiO2 and CaO, and the mass ratio of MgO, SiO2 and CaO in the flux is 0.4-1.6:1-3:0.1-0.7; in step 2, the mixed solvent is a mixed solution of toluene and isopropanol, and the mass ratio of toluene and isopropanol in the mixed solvent is 3-6:9-13.

7. The method for preparing a zirconia toughened alumina ceramic substrate according to claim 1, wherein: In step three, during the heating and drying process, the temperature of zone one is 15-55°C, the temperature of zone two is 45-70°C, and the temperature of zone three is 60-110°C.

8. The method for preparing a zirconia toughened alumina ceramic substrate according to claim 1, wherein: In step 3, the thickness of the strip is 0.2-1.0 mm.

9. The method for preparing a zirconia toughened alumina ceramic substrate according to claim 1, 5 or 6, wherein: In step 2, the mass of the binder is 5%-9% of the total mass of the alumina mixed powder and the flux, the mass of the plasticizer is 2%-6% of the total mass of the alumina mixed powder and the flux, the mass of the dispersant is 0.5%-3% of the total mass of the alumina mixed powder and the flux, and the mass of the mixed solvent is 40%-60% of the total mass of the alumina mixed powder and the flux.

10. The method for preparing a zirconia toughened alumina ceramic substrate according to claim 1, characterized in that: In step 2, the mass ratio of the alumina mixed powder to the flux is 95-97:3-5.

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