A method for preparing yttrium magnesium multiphase transparent ceramics by non-aqueous casting

Abstract

This invention discloses a method for preparing yttrium-magnesium oxide (YMO) multiphase transparent ceramics using non-aqueous gel casting, belonging to the field of ceramic preparation technology. To overcome the problems associated with water-based gel casting, this invention provides a method for preparing YMO multiphase transparent ceramics using non-aqueous gel casting, comprising: ball milling Y2O3, MgO, a dispersant, and a non-aqueous solvent; then adding epoxy resin and a curing agent and ball milling again; the resulting ceramic slurry is defoamed, cured, and dried; then subjected to debinding, sintering densification, cooling, hot isostatic pressing, annealing, and polishing to obtain the YMO multiphase transparent ceramic. This invention overcomes the difficulties in preparing large-size Y2O3-MgO nano-multiphase infrared transparent ceramics and the problem of component inhomogeneity by designing a non-aqueous solvent system and selecting a suitable gel system, and can produce complex-shaped / large-size, uniformly composed YMO nano-multiphase ceramics.

Description

Technical Field

[0001] This invention belongs to the field of ceramic preparation technology, specifically relating to a method for preparing yttrium magnesium multiphase transparent ceramics by non-aqueous injection molding. Background Technology

[0002] Infrared imaging, infrared precision guidance, and infrared countermeasures technologies hold strategic importance in modern military applications. Infrared windows and fairings are key components of infrared technology. They need to bear the aerodynamic load and prevent external environmental factors from corroding and damaging the imaging system. While achieving the protection function, they also need to have high detection sensitivity and anti-interference capabilities. In order to meet the equipment requirements of the new generation of air-to-air missiles to effectively strike highly stealthy, highly maneuverable, and high-speed targets, and to adapt to the national defense needs of future air combat, the development of a new generation of infrared window materials that meet the following requirements has become a research hotspot and focus of various countries: (1) optical performance: high transmittance and low high-temperature infrared thermal emissivity; (2) mechanical performance: impact resistance, high hardness, and high strength; (3) thermodynamic performance: good thermal shock resistance and low coefficient of thermal expansion; (4) excellent chemical properties.

[0003] Y₂O₃ exhibits the smallest emissivity variation with wavelength, the lowest high-temperature infrared radiation coefficient at the same temperature, and low scattering rate, resulting in excellent high-temperature mechanical properties. However, pure-phase yttrium oxide has poor mechanical properties, making it unsuitable for hypersonic Mach applications. By introducing cubic MgO as a second phase to suppress Y₂O₃ grain growth, a new generation of infrared transparent materials with both excellent mechanical and optical properties can be obtained. However, the preparation of high-performance, large-size nanocomposite ceramics with uniform phase distribution remains a key research focus and challenge.

[0004] Gel casting is a near-net-shape forming process developed after slip casting and tape casting. Its principle involves the in-situ solidification of ceramic powder through a macromolecular network formed by a gel system reaction. It was successfully developed by Oak Ridge National Laboratory in the United States. Compared to traditional dry pressing, it offers advantages such as the ability to produce complex shapes, high green body strength, uniform composition, and a simpler manufacturing process. Gel casting systems can be divided into water-based and non-water-based systems. However, when using water-based systems, considerations must be given to the wettability of the solvent system with the powder, the drying rate, and the fact that yttrium oxide and magnesium oxide nanoparticles can react with water. Furthermore, there are currently no reports on the use of non-water-based gel casting technology to prepare yttrium oxide-magnesium oxide nanocomposite transparent ceramics.

[0005] CN113754435A discloses a method for preparing Y2O3-MgO infrared transparent ceramics, comprising the following steps: S1: Weighing Y2O3 and MgO nanoparticles according to a ratio, ball milling, drying, and sieving them respectively, and mixing them evenly to obtain nanocomposite powder; S2: Placing the nanocomposite powder obtained in S1 into a muffle furnace for pre-firing and debinding treatment to remove organic matter from the powder; S3: Placing the debinding nanocomposite powder from S2 into a graphite mold. S3: Hot pressing sintering is performed at a temperature of 900–1200℃, a pressure of 20–40 MPa, and a time of 10–30 min to obtain a multiphase ceramic green body; S4: The multiphase ceramic green body obtained in S3 is connected in series with platinum wire across the positive and negative terminals of an external power supply. An electric field strength of 600–1000 V / cm is applied at a furnace temperature of 1150–1350℃. After flash burning of the multiphase ceramic green body occurs, the current density is controlled at 20–100 mA / mm². 2 The mixture is held for 10 seconds to 5 minutes, then cooled in the furnace to obtain high-density Y₂O₃-MgO ceramics. This method uses hot pressing to prepare multiphase samples, directly placing the powder into a graphite mold and applying uniaxial pressure during sintering to simultaneously complete the forming and sintering. However, this method has significant limitations in its forming capabilities and is only suitable for forming... The following small discs, with limited thickness, can only produce one sample per furnace per batch, and do not have the capability for large-scale production.

[0006] CN109354501A discloses a method for preparing MgAlON transparent ceramics, comprising the following steps: Step 1: Take MgAlON powder and set aside; Step 2: Weigh Y2O3 powder, LiF powder, and SiO2 powder, and mix them according to the mass ratio of LiF content 15%–40%, Y2O3 content 20%–55%, and SiO2 content 25%–60% to obtain a multiphase sintering aid, set aside; Step 3: Take MgAlON powder and multiphase sintering aid, the mass of the multiphase sintering aid… A slurry is prepared by dispersing 0.2%–1.0% MgAlON powder (99%–99.8% by mass) in anhydrous ethanol (99.5% purity) and ball milling it. Step four: After drying the slurry, it is pressed into a green body. Step five: The green body is placed in a high-purity BN crucible and then placed together in a high-temperature sintering furnace. High-purity nitrogen is used as a protective gas, and the temperature is raised to 1750℃–1850℃ and held for 10–30 hours. After natural cooling, it is removed, polished, and the MgAlON transparent ceramic is obtained. Although this method uses anhydrous ethanol as a non-aqueous system, it is not suitable for preparing yttrium oxide-magnesium oxide nanocomposite transparent ceramics. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing multiphase transparent ceramics by non-aqueous injection molding, overcoming the difficulties in preparing large-size Y2O3-MgO nano-multiphase infrared transparent ceramics and the problem of uneven composition. The method of this invention can prepare complex-shaped / large-size, uniformly composed yttrium oxide-magnesium oxide nano-multiphase ceramics by designing a non-aqueous solvent system and selecting a suitable gel system.

[0008] To achieve the above objectives, the present invention provides a method for preparing yttrium magnesium multiphase transparent ceramics by non-aqueous casting molding, comprising the following steps:

[0009] A. Mix Y2O3 nanopowder, MgO nanopowder, dispersant and non-aqueous solvent, and ball mill for the first time. Then add epoxy resin and curing agent, and ball mill for the second time to obtain ceramic slurry.

[0010] B. After defoaming, curing and drying, the ceramic slurry obtained in step A is used to obtain a ceramic green body;

[0011] C. The ceramic green body obtained in step B is calcined in air at 400-850℃ to remove the binder, then heated to 1000-1500℃ for sintering and densification, cooled down, and then hot isostatic pressing is performed at 1000-1500℃ in a high-pressure inert atmosphere. Finally, after annealing and polishing, yttrium magnesium multiphase transparent ceramic is obtained.

[0012] In step A, the volume ratio of Y2O3 nanopowder to MgO nanopowder is 1:9 to 9:1; the non-aqueous solvent is at least one of ethanol, propanol, isopropanol, acetone, butanone, or toluene; the amount of the non-aqueous solvent is 10% to 30% of the total mass of Y2O3 nanopowder and MgO nanopowder.

[0013] Preferably, in the above method, in step A, the volume ratio of Y2O3 nanoparticles to MgO nanoparticles is 1:5 to 5:1.

[0014] More preferably, in the above method, in step A, the volume ratio of the Y2O3 nanopowder to the MgO nanopowder is 1:1.

[0015] In the above method, in step A, the dispersant is polyacrylic acid, herring oil, polyacrylate, or castor oil.

[0016] Preferably, in step A of the above method, the dispersant is polyacrylic acid.

[0017] In the above method, in step A, the amount of dispersant used is 0.1% to 5% of the total mass of Y2O3 nanoparticles and MgO nanoparticles.

[0018] In the above method, in step A, the epoxy resin is ethylene glycol diglycidyl ether (EGDGE) or glycerol glycidyl ester.

[0019] Preferably, in the above method, in step A, the epoxy resin is ethylene glycol diglycidyl ether (EGDGE).

[0020] In the above method, in step A, the amount of epoxy resin used is 1% to 4% of the total mass of Y2O3 nanoparticles and MgO nanoparticles.

[0021] In the above method, in step A, the curing agent is 3,3′-diaminodipropylamine (DPTA), triethylenediamine, or ethylenediamine.

[0022] Preferably, in the above method, in step A, the curing agent is 3,3′-diaminodipropylamine (DPTA).

[0023] In the above method, in step A, the amount of curing agent used is 10-50% of the mass of epoxy resin.

[0024] In the above method, in step A, during the first ball milling, zirconia balls are added, and the amount of zirconia balls added is 2 to 10 times the total mass of Y2O3 nanoparticles and MgO nanoparticles.

[0025] In the above method, in step A, the rotational speed of the first ball mill is 150-240 rad / s.

[0026] In the above method, in step A, the first ball milling time is 30-60 hours.

[0027] In the above method, in step A, the rotational speed of the second ball mill is 150-240 rad / s.

[0028] In the above method, in step A, the second ball milling time is 0.5 to 1 hour.

[0029] In the above method, in step A, the solid content of the obtained ceramic slurry is 40 vol.% to 60 vol.%.

[0030] In the above method, step B involves degassing using vacuum stirring at a vacuum level of 0.1 MPa for a time of 1–10 minutes.

[0031] In the above method, in step B, the curing temperature is 20–80°C.

[0032] In the above method, in step B, the curing time is 30 to 300 minutes.

[0033] In the above method, step B involves drying at a gradient temperature of 25–150°C.

[0034] In the above method, in step B, the drying time is 12 to 48 hours.

[0035] In the above method, in step C, the calcination time at 400–850°C is 1–10 hours.

[0036] In the above method, in step C, the sintering and densification time at 1000-1500℃ is 2-10 hours.

[0037] In the above method, in step C, the pressure of the high-pressure inert atmosphere is 160-200 MPa.

[0038] In the above method, in step C, the hot isostatic pressing sintering time is 0.5 to 6 hours.

[0039] In the above method, step C, the annealing conditions are: in an air atmosphere, at 1000–1400°C for 10–80 hours.

[0040] The beneficial effects of this invention are:

[0041] This invention marks the first successful application of non-aqueous casting molding to prepare large-size / complex-shaped yttrium oxide-magnesium oxide nanocomposite ceramics, offering the following advantages: 1. It enables the preparation of large-size, shape-controllable, and high-performance nanocomposite ceramics with lower molding difficulty, higher yield, and easier preparation of high-performance ceramic samples, solving the problem of dry pressing difficulty in preparing this type of nanoceramic; 2. Compared with aqueous systems, using a non-aqueous solvent system avoids the hydration problem of yttrium oxide and magnesium oxide, and eliminates the need for complex modification treatments of yttrium oxide and magnesium oxide, resulting in a simpler and more stable preparation process; 3. It can prepare ceramic slurries with a solid content as high as 40-60 vol%, producing green samples with high strength, high density, and uniform composition, which is more conducive to the sintering and densification of yttrium oxide-magnesium oxide nanocomposite ceramics, leading to samples with superior optical and mechanical properties. This invention provides a simple, rapid, and large-scale method for preparing transparent yttrium oxide-magnesium oxide nanocomposite ceramics, which is of great significance for promoting its application in the field of optical windows. Attached Figure Description

[0042] Figure 1 This is a transmittance diagram of the yttrium oxide-magnesium oxide nanocomposite transparent ceramic of Example 1 of the present invention.

[0043] Figure 2 This is a SEM image of the yttrium oxide-magnesium oxide nanocomposite transparent ceramic of Example 1 of the present invention. Detailed Implementation

[0044] Specifically, a method for preparing yttrium magnesium multiphase transparent ceramics by non-aqueous casting includes the following steps:

[0045] A. Mix Y2O3 nanopowder, MgO nanopowder, dispersant and non-aqueous solvent, and ball mill for the first time. Then add epoxy resin and curing agent, and ball mill for the second time to obtain ceramic slurry.

[0046] B. After defoaming, curing and drying, the ceramic slurry obtained in step A is used to obtain a ceramic green body;

[0047] C. The ceramic green body obtained in step B is calcined in air at 400-850℃ to remove the binder, then heated to 1000-1500℃ for sintering and densification, cooled down, and then hot isostatic pressing is performed at 1000-1500℃ in a high-pressure inert atmosphere. Finally, after annealing and polishing, yttrium magnesium multiphase transparent ceramic is obtained.

[0048] In step A, the volume ratio of Y2O3 nanopowder to MgO nanopowder is 1:9 to 9:1; the non-aqueous solvent is at least one of ethanol, propanol, isopropanol, acetone, butanone, or toluene; the amount of the non-aqueous solvent is 10% to 30% of the total mass of Y2O3 nanopowder and MgO nanopowder.

[0049] In step A of the method of the present invention, the volume ratio of Y2O3 nanopowder to MgO nanopowder is preferably 1:5 to 5:1; more preferably 1:1.

[0050] The main feature of the non-aqueous injection molding process of this invention as a ceramic molding technology is the use of non-aqueous solvents. Therefore, it is necessary to control the organic components, such as dispersants, epoxy resins, and curing agents, which are essential for gel injection molding. Epoxy resins and curing agents are used to form a gel network, and dispersants are necessary for achieving high solids content, low viscosity, and uniform slurry. The organic components mentioned above need to be selected based on the properties of the slurry, solvent, and powder, as they are all necessary conditions for achieving injection molding.

[0051] In step A of this invention, the dispersant is polyacrylic acid, herring oil, polyacrylate, or castor oil; preferably polyacrylic acid; the amount of dispersant is 0.1% to 5% of the total mass of Y₂O₃ nanoparticles and MgO nanoparticles. In step A, the epoxy resin is ethylene glycol diglycidyl ether (EGDGE) or glycerol glycidyl ester; preferably ethylene glycol diglycidyl ether (EGDGE); the amount of epoxy resin is 1% to 4% of the total mass of Y₂O₃ nanoparticles and MgO nanoparticles. In step A, the curing agent is 3,3′-diaminodipropylamine (DPTA), triethylenediamine, or ethylenediamine; preferably 3,3′-diaminodipropylamine (DPTA); the amount of curing agent is 10% to 50% of the mass of the epoxy resin.

[0052] In step A of this invention, ball milling is performed in stages. The first stage involves adding a dispersant to ensure thorough and uniform mixing of the two phases, which is a prerequisite for proceeding to the second stage. In the second stage, epoxy resin and a curing agent are added to form a gel network. After uniform mixing, the mixture is cured to achieve sample molding. In step A of this invention, the ball milling speed in the first stage is 150–240 rad / s, and the milling time is 30–60 h; the ball milling speed in the second stage is 150–240 rad / s, and the milling time is 0.5–1 h.

[0053] In step A of this invention, during the first ball milling, zirconia balls are added, and the amount of zirconia balls added is 2 to 10 times the total mass of Y2O3 nanopowder and MgO nanopowder.

[0054] This invention employs non-aqueous injection molding and controls the dispersant, epoxy resin, and curing agent to achieve a solid content of 40 vol.% to 60 vol.% in the resulting ceramic slurry. This results in high strength, high density, and uniform composition of the molded sample green body, which is more conducive to the sintering and densification of yttrium oxide-magnesium oxide nanocomposite ceramics, thereby obtaining samples with superior optical and mechanical properties.

[0055] In step B of this invention, the degassing is performed by vacuum stirring, with a vacuum degree of 0.1 MPa and a time of 1 to 10 minutes.

[0056] In step B of this invention, the curing temperature is 20–80°C; the curing time is 30–300 min.

[0057] In step B of this invention, the drying process involves a gradient temperature increase from 25 to 150°C; the drying time is 12 to 48 hours.

[0058] In step C of this invention, the calcination time at 400–850°C is 1–10 h.

[0059] In step C of this invention, the sintering and densification time at 1000-1500℃ is 2-10 hours.

[0060] In step C of this invention, the pressure of the high-pressure inert atmosphere is 160-200 MPa.

[0061] In step C of this invention, the hot isostatic pressing sintering time is 0.5 to 6 hours.

[0062] In step C of this invention, the annealing conditions are: in an air atmosphere, at 1000–1400°C for 10–80 hours.

[0063] The present invention will be further described in detail below through embodiments, but the scope of protection of the present invention is not limited to the embodiments described herein.

[0064] In this embodiment of the invention, the dispersant is polyacrylic acid; the gelling agent is epoxy resin, namely ethylene glycol diglycidyl ether (EGDGE); and the curing agent is 3,3′-diaminodipropylamine (DPTA).

[0065] Example 1

[0066] Step 1, Slurry preparation: Weigh commercial Y2O3 and MgO nanoparticles at a volume ratio of 1:1, and weigh anhydrous ethanol as the organic solvent. Add the composite powder (total mass of Y2O3 and MgO): anhydrous ethanol: dispersant: zirconia balls = 10:1.5:0.1:40 into a ball mill jar and ball mill at 180 rad / s for 40 hours. Then weigh 2 wt% of epoxy resin as a gelling agent and 15 wt% of curing agent as a curing agent into the slurry. Continue ball milling for 30 minutes to obtain a ceramic slurry with a solid content of 50 vol.%.

[0067] Step 2, Sample Forming: After the ceramic slurry obtained in Step 1 is discharged, it is vacuum stirred and degassed at a vacuum degree of 0.1 MPa for 5 minutes. The degassed slurry is then poured into a mold, heated to 40℃ and cured for 150 minutes. The green body is then demolded and placed in an oven for drying. It is first dried at 25℃ for 20 hours, and then the temperature is gradually increased to 120℃ for 12 hours until the weight of the green body no longer decreases, thus obtaining a ceramic green body.

[0068] Step 3, Ceramic Sintering: The ceramic green body is heated to 800℃ in a muffle furnace and held for 6 hours for debinding. Then, the temperature is raised to 1350℃ and held for 6 hours. After naturally cooling to room temperature, a ceramic green body with a relative density of 96% is obtained. The aforementioned ceramic green body is then hot isostatically sintered at 1300℃ and 200MPa argon atmosphere for 2 hours. After sintering, it is annealed at 1200℃ in air atmosphere for 30 hours. After double-sided polishing, yttrium magnesium multiphase infrared transparent ceramic is obtained.

[0069] The 3mm thick sample was found to have a maximum transmittance of 86% at 5μm in the 3-5μm band, an average transmittance of >83%, and a three-point bending strength of 500MPa, demonstrating excellent performance.

[0070] Example 2

[0071] Step 1, Slurry preparation: Weigh Y2O3 and MgO nanoparticles at a volume ratio of 1:1, and weigh anhydrous ethanol and methyl ethyl ketone as organic solvents. Add them to a ball mill jar at a mass ratio of composite powder: anhydrous ethanol: methyl ethyl ketone: dispersant: zirconia balls = 10:0.5:0.8:0.1:40, and ball mill at 180 rad / s for 30 hours. Then weigh 1.5 wt% of epoxy resin as a gelling agent and 10 wt% of curing agent as a curing agent and add it to the slurry. Continue ball milling for 30 minutes to obtain a ceramic slurry with a solid content of 52 vol.%.

[0072] Step 2, Sample Forming: After the ceramic slurry obtained in Step 1 is discharged, it is vacuum stirred and degassed at a vacuum degree of 0.1 MPa for 5 minutes. The degassed slurry is then poured into a mold, heated to 30℃ and cured for 300 minutes. The green body is then demolded and placed in an oven for drying. It is first dried at 25℃ for 20 hours, then heated to 60℃ for 12 hours, and finally gradually heated to 120℃ until the weight of the green body no longer decreases, thus obtaining a ceramic green body.

[0073] Step 3, Ceramic Sintering: The ceramic green body is heated to 800℃ in a muffle furnace and held for 6 hours for debinding. Then, the temperature is raised to 1250℃ and held for 10 hours. After natural cooling to room temperature, a ceramic green body with a relative density of 95% is obtained. This green body is then hot isostatically sintered at 1250℃ and 200MPa argon atmosphere for 6 hours. After sintering, it is annealed at 1100℃ in air atmosphere for 80 hours. After double-sided polishing, yttrium magnesium multiphase infrared transparent ceramic is obtained.

[0074] The maximum transmittance of the 3mm thick sample in the 3-5μm band was measured to be 83%@5μm, the average transmittance was 80%, and the three-point bending strength was 460MPa.

[0075] Example 3

[0076] Step 1, Slurry preparation: Weigh Y2O3 and MgO nanoparticles at a volume ratio of 1:1, and weigh anhydrous ethanol as the organic solvent. Add the composite powder, anhydrous ethanol, dispersant, and zirconia balls in a ball mill jar at a ratio of 10:1.8:0.1:40. Ball mill at 180 rad / s for 40 hours. Then weigh 4 wt% of epoxy resin as the gelling agent and 20 wt% of curing agent as the curing agent and add it to the slurry. Continue ball milling for 30 minutes to obtain a ceramic slurry with a solid content of 45 vol.%.

[0077] Step 2, Sample Forming: After the ceramic slurry obtained in Step 1 is discharged, it is vacuum stirred and degassed at a vacuum degree of 0.1 MPa for 5 minutes. The degassed slurry is then poured into a mold, heated to 35℃ and cured for 60 minutes. The green body is then demolded and placed in an oven for drying. It is first dried at 25℃ for 24 hours, then heated to 50℃ for 12 hours, and finally gradually heated to 120℃ until the weight of the green body no longer changes, thus obtaining a ceramic green body.

[0078] Step 3, ceramic sintering: The ceramic green body is heated to 800℃ in a muffle furnace and held for 6 hours for debinding. Then, the temperature is raised to 1400℃ and held for 2 hours. After natural cooling to room temperature, a ceramic green body with a relative density of 97% is obtained. This green body is then hot isostatically sintered at 1300℃ and 200MPa argon atmosphere for 1 hour. After sintering, it is annealed at 1250℃ in air atmosphere for 10 hours. After double-sided polishing, yttrium magnesium multiphase infrared transparent ceramic is obtained.

[0079] The maximum transmittance of the 3mm thick sample in the 3-5μm band was measured to be 84%@5μm, and the three-point bending strength reached 400MPa.

Claims

1. Process for the preparation of yttrium-magnesia multiphase transparent ceramics by non-aqueous gelcasting, characterized in that: Includes the following steps: A. Mix Y2O3 nanopowder, MgO nanopowder, dispersant and non-aqueous solvent, and ball mill for the first time. Then add epoxy resin and curing agent, and ball mill for the second time to obtain ceramic slurry. B. After defoaming, curing and drying, the ceramic slurry obtained in step A is used to obtain a ceramic green body; C. The ceramic green body obtained in step B is calcined in air at 400~850℃ to remove the binder, then heated to 1000~1500℃ for sintering and densification, cooled down, and then hot isostatic pressing is performed at 1000~1500℃ in a high-pressure inert atmosphere. Finally, after annealing and polishing, yttrium magnesium multiphase transparent ceramic is obtained. In step A, the volume ratio of Y₂O₃ nanopowder to MgO nanopowder is 1:9 to 9:1; the non-aqueous solvent is at least one of ethanol, propanol, isopropanol, acetone, butanone, or toluene; the amount of the non-aqueous solvent is 10% to 30% of the total mass of Y₂O₃ nanopowder and MgO nanopowder. In step A, the amount of dispersant used is 0.1% to 5% of the total mass of Y2O3 nanoparticles and MgO nanoparticles; In step A, the amount of epoxy resin used is 1-4% of the total mass of Y2O3 nanoparticles and MgO nanoparticles; In step A, the amount of curing agent used is 10-50% of the mass of epoxy resin.

2. The method for preparing yttrium-magnesia composite transparent ceramics by non-aqueous-based gelcasting according to claim 1, characterized in that: In step A, the volume ratio of Y2O3 nanoparticles to MgO nanoparticles is 1:5 to 5:

1.

3. The method for preparing yttrium-magnesia composite transparent ceramics by non-aqueous-based gelcasting according to claim 2, characterized in that: In step A, the volume ratio of Y2O3 nanopowder to MgO nanopowder is 1:

1.

4. The method for preparing yttrium-magnesia composite transparent ceramics by non-aqueous-based gelcasting according to claim 1, characterized in that: In step A, the dispersant is polyacrylic acid, herring oil, polyacrylate, or castor oil.

5. The method for preparing yttrium-magnesia composite transparent ceramics by non-aqueous-based gelcasting according to claim 1, characterized in that: In step A, the epoxy resin is ethylene glycol diglycidyl ether or glycerol glycidyl ester.

6. The method of making yttrium magnesium polyphase transparent ceramic by non-aqueous gelcasting according to claim 1, wherein: In step A, the curing agent is 3,3′-diaminodipropylamine, triethylenediamine, or ethylenediamine.

7. The method of claim 1, wherein the non-aqueous-based gelcasting method for preparing yttrium-magnesia composite transparent ceramics is characterized by: In step A, at least one of the following must be satisfied: During the first ball milling, zirconia balls are added, with the amount of zirconia balls being 2 to 10 times the total mass of Y2O3 nanopowder and MgO nanopowder. The rotational speed of the first ball mill is 150~240 rad / s; The first ball milling time is 30-60 hours; The rotational speed of the second ball mill is 150~240 rad / s; The second ball milling time is 0.5~1h.

8. The method for preparing yttrium magnesium multiphase transparent ceramics by non-aqueous casting according to claim 1, characterized in that: In step A, the solid content of the obtained ceramic slurry is 40 vol.% to 60 vol.%.

9. The method for preparing yttrium magnesium multiphase transparent ceramics by non-aqueous casting according to claim 1, characterized in that: In step B, at least one of the following must be satisfied: The degassing process employs vacuum stirring at a vacuum level of 0.1 MPa for a time of 1 to 10 minutes. The curing temperature is 20~80℃; The curing time is 30~300 min; The drying process involves a gradient temperature increase from 25 to 150°C. The drying time is 12-48 hours.

10. The method for preparing yttrium magnesium multiphase transparent ceramics by non-aqueous casting according to claim 1, characterized in that: In step C, at least one of the following must be satisfied: The calcination time at 400~850℃ is 1~10h; The sintering and densification time at 1000~1500℃ is 2~10h; The pressure of the high-pressure inert atmosphere is 160~200MPa; The hot isostatic pressing sintering time is 0.5~6h.

11. The method for preparing yttrium magnesium multiphase transparent ceramics by non-aqueous casting according to claim 1, characterized in that: In step C, the annealing conditions are: in an air atmosphere, at 1000~1400℃ for 10~80 hours.

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