Method for preparing YAG transparent ceramic through two-step sintering

Abstract

The invention discloses a method for preparing YAG transparent ceramic by two-step sintering, which comprises the following steps: 1) weighing yttrium oxide powder and aluminum oxide powder according to a stoichiometric ratio, mixing, and carrying out solid-phase reaction to synthesize YAG powder; 2) performing dry grinding and wet grinding on the obtained YAG powder to obtain mixed slurry; 3) drying the obtained mixed slurry to obtain powder, and performing compression molding and cold isostatic pressing to obtain a ceramic biscuit; and 4) pre-sintering the obtained ceramic biscuit in an oxygen-containing atmosphere, embedding the pre-sintered ceramic with oxide particles, and carrying out hot isostatic pressing sintering to prepare the YAG transparent ceramic. On the basis of obtaining the YAG transparent ceramic with high optical quality, a microstructure with a fine grain size can be obtained, and good mechanical properties are considered; the preparation method is simple, the equipment cost and energy consumption are low, the traditional annealing step can be omitted, and a new thought can be provided for preparation of the high-performance YAG transparent ceramic.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of transparent ceramic preparation, and particularly relates to a method for preparing YAG transparent ceramic through two-step sintering. BACKGROUND

[0002] Yttrium aluminum garnet (YAG) transparent ceramic has been widely studied and applied in solid-state laser gain medium, window material and white light LED, etc. due to its highly symmetrical crystal structure, good thermal, mechanical and optical properties, wide light transmission band and stable physical and chemical properties. YAG has three kinds of coordination polyhedron, i.e. dodecahedron, octahedron and tetrahedron, and its rich replaceable cations endow it with a wide performance range. In recent years, with the deepening of the research on YAG transparent ceramic, the application field and performance index of YAG-based transparent ceramic are further broadened through band engineering adjustment by means of cation substitution, and great progress has been made in spectral adjustment, luminous efficiency improvement, thermal stability improvement and application expansion.

[0003] At present, YAG transparent ceramic is mainly prepared by vacuum reaction sintering with commercial yttrium oxide and aluminum oxide powders as main raw materials. High optical quality YAG transparent ceramic requires almost full densification and no second phase microstructure. Therefore, the sintering temperature is usually above 1700 DEG C, and the holding time is usually more than 10 h. At the same time, liquid phase sintering aid TEOS needs to be added to enhance pore removal and promote densification. However, under the dual action of liquid phase sintering aid and high temperature and long time holding, the grain size of the prepared YAG transparent ceramic is large (usually more than 10 microns), which is not conducive to ensuring the mechanical properties of YAG transparent ceramic. SUMMARY

[0004] The main purpose of the application is to provide a method for preparing YAG transparent ceramic through two-step sintering in view of the problems and deficiencies of the traditional YAG transparent ceramic vacuum sintering process, which can obtain high optical quality YAG transparent ceramic and fine grain size microstructure, and good mechanical properties.

[0005] To achieve the above purpose, the technical scheme adopted by the application is as follows: A method for preparing YAG transparent ceramic through two-step sintering, comprising the following steps: 1) Yttrium oxide and aluminum oxide powders are weighed according to the stoichiometric ratio, and the two are mixed to synthesize YAG powder through solid phase reaction; 2) The obtained YAG powder is dry ground with grinding balls, and sintering aid and ball milling aid are added for wet grinding to obtain mixed slurry; 3) The obtained mixed slurry is dried to obtain powder, which is sieved and then formed and cold isostatic pressed to obtain a ceramic green body; 4) pre-sintering the obtained ceramic green body in an oxygen-containing atmosphere, then embedding the ceramic green body with oxide particles, and performing hot isostatic sintering to obtain the YAG transparent ceramic.

[0006] Preferably, in step 1), the temperature for solid phase reaction is 1380-1420℃, and the time is 2-4h.

[0007] Preferably, in step 2), the amount of TEOS is 0.5-0.7wt% of the mass of YAG powder.

[0008] Preferably, in step 2), the amount of MgO is determined according to the atomic ratio of Si (introduced by decomposition of TEOS): Mg = 1.6-2.

[0009] Preferably, in step 2), the amount of MgO is determined according to the atomic ratio of Si (introduced by decomposition of TEOS): Mg = 1.6-2.

[0010] Preferably, in step 2), the amount of MgO is determined according to the atomic ratio of Si (introduced by decomposition of TEOS): Mg = 1.6-2.

[0011] Preferably, in step 2), the amount of MgO is determined according to the atomic ratio of Si (introduced by decomposition of TEOS): Mg = 1.6-2.

[0012] Preferably, in step 2), the speed of dry grinding is 90-110 r / min, and the time is 10-15h.

[0013] Preferably, in step 2), the speed of dry grinding is 90-110 r / min, and the time is 10-15h.

[0014] Preferably, in step 2), the speed of dry grinding is 90-110 r / min, and the time is 10-15h.

[0015] Preferably, in step 2), the speed of dry grinding is 90-110 r / min, and the time is 10-15h.

[0016] Preferably, in step 3), the pressure for pressing is 10-15 MPa, and the holding time is 1-3min. Preferably, in step 3), the pressure for pressing is 10-15 MPa, and the holding time is 1-3min.

[0017] Preferably, in step 4), the target sintering temperature is 1580-1620℃, and the holding time is 4-12h.

[0018] Preferably, in step 4), the target sintering temperature is 1580-1620℃, and the holding time is 4-12h.

[0019] Further, the pre-sintering step comprises: firstly, increasing the temperature to 1280-1320 DEG C at a rate of 8-12 DEG C / min; and then, increasing the temperature to the target sintering temperature (1580-1620 DEG C) at a rate of 2-5 DEG C / min.

[0020] Further, the oxygen-containing atmosphere is an air atmosphere.

[0021] Further, the pre-sintering step is performed in a muffle furnace.

[0022] In the above scheme, the oxide particles can be selected from zirconia microspheres (0.3-0.6 mm) or gallium-containing garnet powder In the above scheme, the temperature used in the hot isostatic sintering step of step 4) is 1650-1700 DEG C, the pressure is 180-200 MPa, and the time is 3-5 h.

[0023] The YAG transparent ceramic prepared according to the above scheme has a stoichiometric ratio of components, a dense microstructure with almost no pores, uniform grain size (average grain size of 2.5-3.8 µm), and a linear transmittance of 80% at 1064 nm for a 2.5 mm thick sample.

[0024] The present application provides a two-step sintering method for preparing YAG transparent ceramic, which comprises the following steps: firstly, synthesizing single-phase YAG powder by solid-phase reaction of yttrium oxide and aluminum oxide powder; then, performing dry grinding and wet grinding on the YAG powder, drying, and sieving to prepare precursor powder; and then, performing cold isostatic pressing to obtain a ceramic green body; pre-sintering the ceramic green body in an air atmosphere; and finally, performing hot isostatic sintering to obtain high-quality YAG transparent ceramic. On the basis of ensuring high optical quality YAG transparent ceramic, the present application promotes the reduction of sintering temperature and the obtaining of fine-grained microstructure to ensure good mechanical properties. Firstly, synthesizing single-phase YAG powder by solid-phase reaction is beneficial to improving the problems in the traditional yttrium oxide-aluminum oxide composite green body sintering process in an air atmosphere, such as the volume expansion of the phase transition to extra wrap gas, which hinders the densification of the ceramic matrix. Then, the dry grinding and wet grinding process refines the particle size of the synthesized powder and improves the sintering activity of the powder. In combination with the pre-sintering in an oxygen-containing atmosphere and the hot isostatic sintering, the residual pores in the ceramic matrix are effectively removed, and the oxygen partial pressure is provided during the hot isostatic sintering to inhibit oxygen vacancies, thereby promoting the obtaining of fine-grained high optical quality YAG transparent ceramic. Compared with the prior art, the present application has the following beneficial effects: 1) Compared with the traditional vacuum sintering process, the present application adopts an air atmosphere segmented pre-sintering process, which can be performed in a muffle furnace, has low requirements for equipment, and can be operated in batches.

[0025] 2) The single-phase YAG blank sintering adopted by the application is conducive to reducing the temperature of reaction sintering, and the dry grinding + wet grinding process refines the particle size of the YAG powder synthesized by reaction, improves the sintering activity of the subsequent powder, and is also conducive to further reducing the reaction sintering temperature; 3) On the basis of the single-phase YAG blank, the application further combines the segmented pre-sintering process in an oxygen-containing atmosphere. In the sintering process of the single-phase YAG component, no additional air is wrapped into the blank to hinder densification due to phase change, which can effectively promote the microstructure with fine grain size, and good optical and mechanical properties are taken into account. In addition, the embedded oxide particles can provide oxygen partial pressure during hot isostatic pressing sintering, reduce the oxygen vacancies of YAG transparent ceramics, omit the subsequent annealing process required in the traditional sintering process, avoid the expansion of residual pores in the annealing process, reduce the optical quality of the ceramic, and have wide applicability.

[0026] 4) The preparation method disclosed by the application is relatively simple, the cost of equipment and energy consumption are low, and the application can provide a new idea for the preparation of high-performance YAG transparent ceramics. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The YAG powder morphology and particle size distribution obtained in Example 1 of the application are shown in the figure.

[0028] Figure 2 The linear transmittance of the 2.5mm thick YAG transparent ceramic prepared in Example 1 of the application and the sample photo are shown in the figure.

[0029] Figure 3 The microstructure of the YAG transparent ceramic obtained in Example 1 of the application is shown in the figure.

[0030] Figure 4 The microstructure of the YAG transparent ceramic described in Comparative Example 1 is shown in the figure.

[0031] Figure 5 The physical map of the YAG transparent ceramic obtained in Comparative Example 2 is shown in the figure.

[0032] Figure 6 The physical map of the YAG transparent ceramic obtained in Comparative Example 4 is shown in the figure. DETAILED DESCRIPTION

[0033] The technical solutions of the application will be described clearly and completely in combination with the drawings and specific embodiments, but those skilled in the art will understand that the following described embodiments are part of the embodiments of the application, not all the embodiments, and are only used to illustrate the application, and should not be regarded as limiting the scope of the application.

[0034] Example 1 A two-step sintering method for preparing YAG transparent ceramic, comprising the following steps: (1) The yttrium oxide and aluminum oxide powders mixed in a stoichiometric ratio of 3:5 are solid-phase reacted at 1400°C for 2h in a muffle furnace to synthesize YAG powders; (2) The prepared YAG ceramic powders and aluminum oxide balls are added to a ball mill tank, dry-milled for 12h, the ball milling speed is 110r / min, and the ball-to-material ratio is 1:4; (3) Anhydrous ethanol (2 times the mass of the YAG ceramic powders), TEOS (0.5 wt% of the mass of the YAG ceramic powders), and MgO (the amount is determined according to the atomic ratio Si:Mg=1.6) are added to the ball mill tank, ball-milled for 24h, and the ball milling speed is 120r / min; (4) The powders after rotary evaporation and vacuum drying are sieved through a 200-mesh sieve and then pressed into a green body (the pressure is 12 MPa, and the pressure holding time is 2min), and the green body is subjected to cold isostatic pressing (200MPa, pressure holding time of 10min) to obtain a ceramic green body; (5) The obtained ceramic green body is first heated to 1300°C at a rate of 10°C / min, and then heated to 1600°C at a rate of 2°C / min in an air atmosphere in a muffle furnace, and sintered for 6h; then the pre-sintered YAG ceramic is embedded in zirconia microspheres with a diameter of 0.3mm, and subjected to hot isostatic pressing sintering at 1700°C and 200MPa for 5h to obtain a YAG transparent ceramic, and the thickness of the polished YAG transparent ceramic is 2.5mm.

[0035] Figure 1 The morphology and particle size distribution of the single-phase YAG powder obtained in step (3) of this example can be seen from the figure, and the obtained powder has uniform morphology and narrow particle size distribution, and the average particle size is about 500nm, which is beneficial to the uniform sintering and densification of the ceramic. The sintering of the single-phase powder effectively avoids the volume expansion of the green body caused by phase transformation during the reaction sintering process, which leads to the entry of additional air into the green body.

[0036] Figure 2 The linear transmittance test results and sample physical map of the YAG transparent ceramic obtained in this example can be seen from the figure, and the embedded sintered YAG transparent ceramic is almost transparent and colorless without annealing, and the text behind the vertical YAG transparent ceramic is clear, and the linear transmittance at 1064nm is 80.02%, which is comparable to the optical quality of the YAG transparent ceramic prepared by vacuum reaction sintering.

[0037] This invention utilizes pre-sintering of single-phase YAG powder into a green body under low-temperature air atmosphere, combined with hot isostatic pressing to further eliminate residual pores left by large molecular inert gases in the air, thus preparing YAG transparent ceramics with high optical quality. This provides a method for preparing YAG transparent ceramics that differs from the traditional high-temperature vacuum reaction sintering method. It features low pre-sintering equipment cost, fine grain size (2.5-3.8 μm), and good optical quality, and exhibits excellent mechanical properties during use.

[0038] Example 2 A two-step sintering method for preparing transparent YAG ceramics includes the following steps: (1) YAG powder was synthesized by solid-phase reaction of yttrium oxide and alumina powder mixed in a stoichiometric ratio of 3:5 in a muffle furnace at 1380℃ for 4 hours. (2) The prepared YAG ceramic powder and alumina balls were added to a ball mill jar and dry-milled for 15 hours at a ball mill speed of 90 r / min; the ball-to-material ratio was 1:3. (3) Add anhydrous ethanol (twice the mass of YAG ceramic powder), TEOS (0.7wt% of the mass of YAG ceramic powder), and MgO (the amount of which is determined with reference to the atomic ratio Si:Mg=1.6) into the ball mill jar and ball mill for 20 hours at a speed of 140 r / min. (4) After rotary evaporation and vacuum drying, the powder is passed through a 200-mesh sieve and pressed into shape (pressure of 10 MPa, holding time of 3 min). After cold isostatic pressing (holding pressure of 250 MPa for 5 min), a ceramic blank is obtained. (5) The obtained ceramic blank was heated to 1280°C at a rate of 12°C / min in an air atmosphere and a muffle furnace, and then heated to 1580°C at a rate of 2°C / min. It was sintered at 1580°C for 12 hours. Then the pre-fired YAG ceramic was embedded in zirconia microspheres with a diameter of 0.6 mm and subjected to hot isostatic pressing sintering, specifically sintering at 1650°C and 180 MPa for 5 hours to obtain transparent YAG ceramic with a thickness of 2.5 mm after polishing.

[0039] Example 3 A two-step sintering method for preparing transparent YAG ceramics includes the following steps: (1) YAG powder was synthesized by solid-phase reaction of yttrium oxide and alumina powder mixed in a stoichiometric ratio of 3:5 in a muffle furnace at 1420℃ for 2 hours. (2) The prepared YAG ceramic powder and alumina balls were added to a ball mill jar and dry-milled for 15 hours at a ball mill speed of 90 r / min; the ball-to-material ratio was 1:4. (3) Anhydrous ethanol (2 times the mass of the YAG ceramic powder), TEOS (0.6wt% of the mass of the YAG ceramic powder), and MgO (the amount is determined according to the atomic ratio of Si:Mg=2) are added to the ball mill tank, and ball milling is performed for 20h at a speed of 120r / min; (4) The powder after rotary evaporation and vacuum drying is sieved through a 200 mesh sieve and then is pressed into a green body (the pressure is 15 MPa, and the time is 1min), and a ceramic green body is obtained after cold isostatic pressing at 200MPa for 5min; (5) The ceramic green body obtained is first heated to 1320℃ at a rate of 8℃ / min, and then heated to 1620℃ at a rate of 5℃ / min in an air atmosphere and a muffle furnace, and sintered at 1620℃ for 4h; then the pre-sintered YAG ceramic is embedded in zirconia microspheres with a diameter of 0.3mm, and is subjected to hot isostatic pressing sintering at 1700℃ and 200MPa for 3h to obtain a YAG transparent ceramic, and the thickness of the polished YAG transparent ceramic is 2.5mm.

[0040] Comparative Example 1 A method for preparing a YAG transparent ceramic by a conventional vacuum sintering process, comprising the following steps: (1) Yttrium oxide and aluminum oxide powders in a stoichiometric ratio of 3:5, aluminum oxide balls, anhydrous ethanol (2 times the mass of the ceramic powder), TEOS (0.5wt% of the mass of the ceramic powder), and MgO (the amount is determined according to the atomic ratio of Si:Mg=1.6) are added to the ball mill tank, and ball milling is performed for 24h at a speed of 120r / min; the ball-to-material ratio is 1:4; (2) The powder after rotary evaporation and vacuum drying is sieved through a 200 mesh sieve and then is pressed into a green body (the pressure is 15 MPa, and the holding time is 1min), and a ceramic green body of the mixed powder is obtained after cold isostatic pressing (200MPa for 5min); (3) The ceramic green body obtained is calcined at 800℃ for 6h in a muffle furnace to remove organic impurities, and then is heated to 1300℃ at a rate of 10℃ / min in a high vacuum furnace (10 -3 Pa), and then is heated to 1780℃ at a rate of 2℃ / min and sintered for 10h to obtain a YAG transparent ceramic, which is annealed at 1450℃ in an air atmosphere for 10h, and the thickness of the polished YAG transparent ceramic is 2.5mm.

[0041] The microstructure of the YAG transparent ceramic obtained in Comparative Example 1 is shown in Figure 4 It can be seen that the grain of the obtained product is relatively coarse (significantly higher than that of Example 1), which limits the mechanical strength.

[0042] Comparative Example 2 A method for preparing a YAG transparent ceramic, comprising the following steps: (1) Yttrium oxide and aluminum oxide powders in a stoichiometric ratio of 3:5, alumina balls, anhydrous ethanol (2 times the mass of the ceramic powder), TEOS (0.5 wt% of the mass of the ceramic powder), and MgO (determined according to the atomic ratio Si:Mg = 1.6) were added to a ball mill tank, and ball milling was performed at 120 r / min for 24 h; the ball-to-material ratio was 1:4; (2) The powder obtained by rotary evaporation and vacuum drying was sieved through a 200-mesh screen and then pressed into a shape (pressure 15 MPa, pressure holding time 1 min), and a ceramic green body was obtained by cold isostatic pressing (200 MPa, pressure holding time 5 min); (3) The ceramic green body obtained was subjected to reaction sintering in a muffle furnace, and the temperature was raised to 1300℃ at a rate of 10℃ / min, and then raised to 1650℃ at a rate of 2℃ / min, and sintered at 1650℃ for 6 h; then the pre-sintered YAG ceramic was embedded in zirconia microspheres with a diameter of 0.3 mm, and subjected to hot isostatic sintering at 1750℃ and 200 MPa for 5 h to obtain a YAG transparent ceramic, and the thickness of the polished ceramic was 2.5 mm.

[0043] The morphology of the YAG transparent ceramic prepared by reaction sintering in air in Comparative Example 2 is shown in Figure 5 It can be seen that, during the reaction sintering in air as described in Comparative Example 1, the green body swells due to phase transition, and additional air is trapped, making it more difficult to remove pores and densify. It can be seen that the residual pores seriously degrade the optical quality of the transparent ceramic sample, and the text on the back of the ceramic is not clear.

[0044] Comparative Example 3 A method for preparing a YAG transparent ceramic by two-step sintering, comprising the following steps: (1) Yttrium oxide and aluminum oxide powders in a stoichiometric ratio of 3:5 were mixed and subjected to solid-phase reaction synthesis of YAG powders at 1400℃ for 2 h in a muffle furnace; (2) The prepared YAG ceramic powder and alumina balls were added to a ball mill tank, and dry milling was performed at 110 r / min for 12 h; the ball-to-material ratio was 1:4; (3) Anhydrous ethanol (2 times the mass of the YAG ceramic powder), TEOS (0.5 wt% of the mass of the YAG ceramic powder), and MgO (determined according to the atomic ratio Si:Mg = 1.6) were added to the ball mill tank, and ball milling was performed at 120 r / min for 24 h; (4) The powder obtained by rotary evaporation and vacuum drying was sieved through a 200-mesh screen and then pressed into a shape (pressure 12 MPa, pressure holding time 2 min), and a ceramic green body was obtained by cold isostatic pressing (200 MPa, pressure holding time 10 min); (5) the obtained ceramic green body is first heated to 1320°C at a rate of 4°C / min, and then heated to 1600°C at a rate of 2°C / min in an air atmosphere and a muffle furnace, and sintered for 6h; then the pre-sintered YAG ceramic is embedded in zirconia microspheres with a diameter of 0.3 mm, and is subjected to hot isostatic pressing sintering, specifically sintering at 1700°C and 200 MPa for 5h, to obtain a YAG transparent ceramic, and the thickness of the polished YAG transparent ceramic is 2.5mm.

[0045] The results show that the sintering density and optical quality of the obtained ceramic product are poor.

[0046] Comparative Example 4 A method for preparing a YAG transparent ceramic by two-step sintering, comprising the following steps: (1) Yttrium oxide and aluminum oxide powders mixed in a stoichiometric ratio of 3:5 are subjected to solid-phase reaction synthesis to obtain YAG powders at 1420°C for 2h in a muffle furnace; (2) the prepared YAG ceramic powders and aluminum oxide balls are added to a ball mill tank, and dry milling is performed for 15h at a ball mill speed of 90r / min; the ball-to-material ratio is 1:4; (3) anhydrous ethanol (2 times the mass of the YAG ceramic powders), TEOS (0.5wt% of the mass of the YAG ceramic powders), and MgO (the amount is determined according to the condition that the atomic ratio of Si:Mg is 1.6) are added to the ball mill tank, and ball milling is performed for 20h at a ball mill speed of 120r / min; (4) the powders after rotary evaporation and vacuum drying are sieved through a 200 mesh sieve, and then are pressed into a green body (the pressure is 15 MPa, and the time is 1min); and the green body is subjected to cold isostatic pressing at 200MPa for 5min to obtain a ceramic green body; (5) the obtained ceramic green body is first heated to 1320°C at a rate of 4°C / min, and then heated to 1600°C at a rate of 2°C / min in an air atmosphere and a muffle furnace, and sintered for 6h; then the pre-sintered YAG ceramic is embedded in zirconia microspheres with a diameter of 0.3 mm, and is subjected to hot isostatic pressing sintering, specifically sintering at 1700°C and 200 MPa for 5h, to obtain a YAG transparent ceramic, and the thickness of the polished YAG transparent ceramic is 2.5mm.

[0047] Figure 6 The unpolished and polished samples of the YAG transparent ceramic obtained by directly performing hot isostatic pressing sintering without embedding zirconia microspheres can be seen to have a red appearance due to oxygen vacancies, and need to be subjected to traditional annealing treatment.

[0048] Although the present application has been described with reference to specific embodiments, it is understood that these embodiments are merely illustrative of the present application and are not to be construed as limiting the present application. It is understood that various modifications or equivalent arrangements can be made to the embodiments without departing from the spirit and scope of the present application. Therefore, the appended claims should be construed to include all such modifications and equivalents within their scope.

Claims

1. A method for preparing YAG transparent ceramics by two-step sintering, characterized in that, The method comprises the following steps: 1) Yttrium oxide and aluminum oxide powders are weighed in stoichiometric ratio, and the two are mixed to perform solid phase reaction synthesis of YAG powder; 2) the obtained YAG powder is dry ground with grinding balls, then sintering aids and ball milling aids are added to perform wet grinding, to obtain mixed slurry; 3) the obtained mixed slurry is dried to obtain powder, which is sieved, then pressed into shape, cold isostatic pressed, to obtain ceramic green body; 4) the obtained ceramic green body is pre-sintered in an oxygen-containing atmosphere, then the pre-sintered ceramic is embedded with oxide particles, and hot isostatic sintering is performed, to prepare the YAG transparent ceramic.

2. The method of claim 1, wherein, In step 1), the temperature for solid phase reaction is 1380-1420℃, and the time is 2-4h.

3. The method of claim 1, wherein, The sintering aid comprises TEOS and MgO.

4. The method of claim 1, wherein, The oxide particles are zirconium oxide microspheres or gallium-containing garnet powder.

5. The method of claim 1, wherein, In step 2), the wet grinding step is performed at a rotating speed of 120-140r / min for 20-24h.

6. The method of claim 1, wherein, In step 3), the cold isostatic pressing step is performed at a pressure of 200-250 MPa for 5-10 min.

7. The method of claim 1, wherein, In step 4), the target sintering temperature for the pre-sintering step is 1580-1620℃, and the holding time is 4-12h.

8. The method of claim 7, wherein, The pre-sintering step comprises: first, heating at a rate of 8-12℃ / min to 1280-1320℃; then, heating at a rate of 2-5℃ / min to the target sintering temperature.

9. The method of claim 1, wherein, In step 4), the hot isostatic sintering step is performed at a temperature of 1650-1700℃, a pressure of 180-200 MPa, and a time of 3-5h.

10. The YAG transparent ceramic produced according to the method of any one of claims 1 to 9, characterized in that, The components thereof are in stoichiometric ratio, the microstructure is dense, the grain size is uniform, and the average grain size ranges from 2.5 to 3.8μm; the linear transmittance of a 2.5mm-thick sample at 1064nm reaches 80%.

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