A method for preparing YAG-based transparent ceramic by using synchronous precipitation

Abstract

The application discloses a method for preparing YAG-based transparent ceramic by using a synchronous precipitation method. x Re 1‑x )3Al5O 12 Stoichiometrically, Y(NO3)3.6H2O, Al(NO3)3, Re(NO3)3 and MgCl2 are weighed as mixed powder raw materials, ultrapure water is weighed in proportion as a solution, and polyacrylic acid is weighed in proportion as a dispersant; after the above raw materials are configured into a solution, dry ice particles are added, and high-dispersed mixed powder is obtained by synchronous precipitation; the green body is formed by calcining and pressing, and then transparent ceramic is obtained by calcining and vacuum sintering; the method uses ultrapure water as a solvent and adopts a synchronous precipitation method, so that the preparation of mixed powder with high sintering activity, high dispersion, high uniformity and no agglomeration can be directly realized; and the method is environment-friendly and has high raw material utilization.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of advanced optical functional transparent ceramics, in particular to a method for preparing YAG-based transparent ceramics by using a synchronous precipitation method. BACKGROUND

[0002] Since 1990s, Japanese scientists successfully prepared high-quality Nd 3+ ion-doped YAG transparent ceramics by high-temperature solid-phase method, and used it as the gain medium of solid-state laser, successfully realized laser output. Since then, a large number of domestic and foreign researchers have begun to study YAG-based transparent ceramics, and have made great research achievements.

[0003] YAG is short for yttrium aluminum garnet, and its chemical formula is Y3Al5O 12 , which has excellent optical, thermal and mechanical properties, and is widely used in high-temperature structural materials and luminescent matrix materials. In the YAG lattice, Y 3+ has a unique electronic structure, which makes it easy to be replaced by heteroion (cations) with similar ionic radius to Y 3+ ion in the form of solid solution. Therefore, YAG is usually used as a matrix material, and through doping other luminescent ions, it can realize its own luminescence. So far, a variety of luminescent ions have been doped into the YAG lattice, mainly including Eu 3+ , Tb 3+ , Ce 3+ , Gd 3+ , Yb 3+ , Er 3+ , Nd 3+ , Sm 3+ and other ions.

[0004] At present, domestic and foreign scholars often adopt the method of solid phase reaction combined with vacuum sintering to prepare YAG transparent ceramic; although, by using high-purity raw materials (i.e. purity ≥ 99.99%) and accurate proportioning according to the stoichiometric ratio, the preparation of YAG transparent ceramic can be realized, but in the preparation process of the ceramic, due to the difference in particle size of different raw material powders, it is often difficult to obtain highly uniform mixed powders, so that the ceramic product after sintering has a large number of scattering centers. Although some scholars use the method of coprecipitation to realize the preparation of high-quality YAG transparent ceramic, but limited by the coprecipitation preparation process, the precipitate often needs to be repeatedly washed or even pickled in the preparation process of the ceramic to realize the preparation of the ceramic. In addition, due to the inconsistent precipitation rate of different cations, the coprecipitated product often needs to be ground or ball milled to be used for the preparation of high-quality transparent ceramic, which cannot meet the batch production of transparent ceramic. Although the sol-gel process can also meet the preparation of high-quality YAG transparent ceramic, but this preparation method needs a long time, and special degreasing process is needed to realize the ceramic powder that can be used for transparent ceramic sintering. SUMMARY

[0005] In view of the above technical deficiencies, the purpose of the present application is to provide a method for preparing YAG-based transparent ceramic by using a synchronous precipitation method, which uses ultrapure water as a solvent and adopts a synchronous precipitation method, is environmentally friendly, has high raw material utilization rate, and can directly realize the preparation of mixed powder with high sintering activity, high dispersion, high uniformity and no agglomeration.

[0006] To solve the above technical problems, the present application adopts the following technical solutions:

[0007] The present application provides a method for preparing YAG-based transparent ceramic by using a synchronous precipitation method, comprising the following steps:

[0008] S1 raw material selection: according to (Y x Re 1-x )3Al5O 12 The stoichiometric amount of Y(NO3)3·6H2O, Al(NO3)3, Re(NO3)3 and MgCl2 is weighed as the mixed powder raw material, the ultrapure water is weighed according to the mass solid content of 34-42wt.% as the configuration solution, the appropriate amount of dry ice is weighed as the synchronous precipitation raw material, and the polyacrylic acid is weighed according to the proportion as the dispersant;

[0009] S2 solution preparation: add ultrapure water to Y(NO3)3·6H2O, Al(NO3)3 and Re(NO3)3 weighed in step S1, adjust the mass solid content of the slurry to 34-42wt.%, add Y3Al5O 12 0.1-1.0wt% of polyacrylic acid, add sintering aid, and stir uniformly;

[0010] S3 Synchronization precipitation: adding dry ice particles to the solution obtained in step S2 to obtain ice crystal precipitation, and drying the ice crystal by freeze-drying to obtain a highly dispersed mixed powder;

[0011] S4 Green body forming: calcining the powder obtained in step S3, then sieving to obtain a mixed powder that can be used for forming, pressing and forming the obtained powder, and then cold isostatic pressing to obtain a ceramic green body;

[0012] S5 Ceramic preparation: calcining the green body obtained in step S4, then vacuum sintering, annealing the obtained ceramic, and then double-side polishing to obtain a YAG-based transparent ceramic product.

[0013] Preferably, in step S1, the raw materials are weighed according to the stoichiometric ratio (Y x Re 1-x )3Al5O 12 , wherein 0.01≤x≤0.5; the Re 3+ ion is Eu 3+ , Tb 3+ , Ce 3+ , Gd 3+ , Yb 3+ , Er 3+ , Nd 3+ , Sm 3+ , Pr 3+ ion.

[0014] Preferably, in step S1, the raw materials are all commercially available high-purity raw materials.

[0015] Preferably, in step S2, the sintering aid is a combination of TEOS and MgCl2, the amount of TEOS added is 0.1-0.8wt% of the total mass of Y3Al5O 12 , and the amount of MgCl2 added is 0.2-0.8wt% of the total mass of Y3Al5O 12 .

[0016] Preferably, in step S2, all the raw materials are stirred using a high-speed disperser, the stirring time is 30-60min, and the stirring speed is 800-1200r / min.

[0017] Preferably, in step S3, dry ice particles with a diameter of Ф3mm are selected, and the amount added is 3-5 times the total mass of Y3Al5O 12 .

[0018] Preferably, in step S4, the calcination temperature is 500-600℃.

[0019] Preferably, in step S4, the mesh size is 100 mesh, and the sieving times are more than 3.

[0020] Preferably, in step S4, the pressure of cold isostatic pressing is 200 MPa, and the cold isostatic time is 5-10 min.

[0021] Preferably, in step S5, the calcination temperature is 600-900℃, the vacuum sintering temperature is 1760-1820℃, the holding time is 8-30 h, and the vacuum degree is ≤9.0×10-3Pa. -3 Pa.

[0022] The present application has the following beneficial effects:

[0023] (1) The preparation method uses ultrapure water as a solvent and adopts a synchronous precipitation method to directly prepare high-dispersion and high-uniformity mixed powder, and then high-quality YAG-based transparent ceramic can be easily prepared through dry pressing and vacuum sintering; the synthesized mixed powder has the characteristics of high sintering activity, good dispersion, and no agglomeration; and the problems of the solid-phase reaction method combined with vacuum sintering, such as the inability to obtain highly uniform mixed powder and the existence of a large number of scattering centers in the sintered ceramic product, are overcome.

[0024] (2) The method does not need to rinse the precipitate, does not need to grind, and can obtain high-uniformity powder without the common technical problem of uneven powder composition caused by different cation precipitation rates; the prepared ceramic has excellent optical performance and no segregation phenomenon; the preparation process has no by-products, is energy-saving and environmentally friendly, and has high raw material utilization; and the problems of the traditional co-precipitation method, such as the need for repeated rinsing or even pickling of the precipitate and the need for grinding or ball milling of the co-precipitated product, are overcome. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description, and obviously, other drawings can also be obtained by those skilled in the art without creative labor.

[0026] Figure 1 The SEM images of the powders prepared by Example 1 and Example 2 after freeze-drying without calcination and after calcination are shown in (a) uncalcined (Y 0.998 Ce 0.002 )3Al5O 12 , (b) uncalcined (Y 0.998 Nd 0.002 )3Al5O 12 , and (c) calcined (Y 0.998 Ce 0.002)3Al5O 12 , (d) the calcined (Y 0.998 Nd 0.002 )3Al5O 12 SEM images of the initial mixed powder;

[0027] Figure 2 SEM images of the cross section of Ce:YAG transparent ceramic prepared in Example 1 of the present application sintered at 1500℃ and 1600℃;

[0028] Figure 3 Optical transmittance curve of Ce:YAG transparent ceramic prepared in Example 1 of the present application;

[0029] Figure 4 Physical map of the sample of Ce:YAG transparent ceramic prepared in Example 1 of the present application;

[0030] Figure 5 SEM microstructure images of the surface and cross section of Nd:YAG transparent ceramic prepared in Example 2 of the present application, wherein (a) is the surface and (b) is the cross section;

[0031] Figure 6 Physical map of Yb:YAG transparent ceramic prepared in Example 3 of the present application and its optical transmittance test results. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0033] Example 1

[0034] A method for preparing YAG-based transparent ceramic by using a synchronous precipitation method, comprising the following steps:

[0035] (1) Selection of raw materials: selecting commercial high-purity Y(NO3)3·6H2O, commercial high-purity Al(NO3)3, commercial high-purity Ce(NO3)3, and commercial high-purity MgCl2 as mixed powder raw materials, selecting ultrapure water for solution preparation, selecting an appropriate amount of dry ice as a synchronous precipitation raw material, and selecting polyacrylic acid as a dispersant;

[0036] (2) Solution preparation: commercial high-purity Y(NO3)3·6H2O, Al(NO3)3, and Ce(NO3)3 are weighed according to the stoichiometric ratio (Y 0.998 Ce 0.002)3Al5O 12 , adding ultrapure water, adjusting the mass solid content of the slurry to 34wt.%, adding (Y 0.998 Ce 0.002 )3Al5O 12 0.1wt% of polyacrylic acid in total mass, adding (Y 0.998 Ce 0.002 )3Al5O 12 0.1wt% of TEOS in total mass, adding (Y 0.998 Ce 0.002 )3Al5O 12 0.2wt% of MgCl2 in total mass, the TEOS and MgCl2 being sintering aids; using a high-speed disperser to stir all raw materials, the stirring time being 45min and the stirring speed being 1000r / min;

[0037] (3) Simultaneous precipitation: adding (Y 0.998 Ce 0.002 )3Al5O 12 3mm dry ice particles in total mass of 3 times, obtaining ice crystal precipitation, using freeze-drying to dry the ice crystals, obtaining highly dispersed (Y 0.998 Ce 0.002 )3Al5O 12 Mixed powder, the SEM image of which is shown in Figure 1 ,

[0038] (4) Green body forming: calcining the powder obtained in step (3), the calcination temperature being 550℃, then sieving, the sieving mesh number being 100 meshes, and the sieving number being 3 times, obtaining mixed powder that can be used for forming, pressing and forming the obtained powder, then cold isostatic pressing, the cold isostatic pressure being 200MPa and the cold isostatic time being 5min, obtaining a ceramic green body;

[0039] (5) Ceramic preparation: calcining the green body, the calcination temperature being 800℃, then vacuum sintering, the vacuum sintering temperature being 1780℃, the holding time being 8h, and the vacuum degree being ≤9.0×10 -3 Pa; annealing the obtained ceramic, then double-side polishing, obtaining a Ce:YAG transparent ceramic product. As shown in Figure 3 and Figure 4 , the transmittance is high.

[0040] Example 2

[0041] A method for preparing a YAG-based transparent ceramic by using a simultaneous precipitation method, comprising the following steps:

[0042] (1) Raw material selection: Select commercial high-purity Y(NO3)3·6H2O, commercial high-purity Al(NO3)3, commercial high-purity Nd(NO3)3, and commercial high-purity MgCl2 as mixed powder raw materials, select ultrapure water for solution preparation, select an appropriate amount of dry ice as a synchronous precipitation raw material, and select polyacrylic acid as a dispersant;

[0043] (2) Solution preparation: Weigh commercial high-purity Y(NO3)3·6H2O, Al(NO3)3, and Nd(NO3)3 according to the stoichiometric ratio (Y 0.998 Nd 0.002 )3Al5O 12 , add ultrapure water, adjust the slurry mass solid content to 38wt.%, add 0.10wt% of polyacrylic acid to the total mass of (Y 0.998 Nd 0.002 )3Al5O 12 , add 0.1wt% of TEOS to the total mass of (Y 0.998 Nd 0.002 )3Al5O 12 , and add 0.2wt% of MgCl2 to the total mass of (Y 0.998 Nd 0.002 )3Al5O 12 , use a high-speed disperser to stir all the raw materials, the stirring time is 60min, and the stirring speed is 1200r / min;

[0044] (3) Synchronous precipitation: Add 5 times the total mass of Ф5mm dry ice particles to the solution obtained in step (2) (Y 0.998 Nd 0.002 )3Al5O 12 , obtain ice crystal precipitation, dry the ice crystals using freeze-drying method, and obtain high-dispersion (Y 0.998 Nd 0.002 )3Al5O 12 mixed powder, the SEM of which is shown in Figure 1 (b);

[0045] (4) Green body forming: Calcine the powder obtained in step (3), the calcination temperature is 800℃, then sieve, the sieve mesh size is 100 meshes, and the sieving times is 3 times, obtain mixed powder for forming, press the obtained powder into a tablet, then cold isostatic pressing, the cold isostatic pressure is 200MPa, and the cold isostatic time is 10min, obtain ceramic green body;

[0046] (5) Ceramic preparation: Calcine the obtained green body, the calcination temperature is 900℃, then vacuum sintering, the vacuum sintering temperature is 1780℃, the holding time is 30h, the vacuum degree is ≤9.0×10 -3Pa, the obtained ceramic is annealed, and then double-side polished, to obtain a Ce:YAG transparent ceramic product.

[0047] Example 3

[0048] A method for preparing a YAG-based transparent ceramic by using a synchronous precipitation method, comprising the following steps:

[0049] (1) Selection of raw materials: selecting commercial high-purity Y(NO3)3·6H2O, commercial high-purity Al(NO3)3, commercial high-purity Yb(NO3)3, and commercial high-purity MgCl2 as mixed powder raw materials, selecting ultrapure water for solution preparation, selecting an appropriate amount of dry ice as a synchronous precipitation raw material, and selecting polyacrylic acid as a dispersant;

[0050] (2) Solution preparation: weighing commercial high-purity Y(NO3)3·6H2O, Al(NO3)3, and Yb(NO3)3 according to the stoichiometric ratio (Y 0.98 Yb 0.02 )3Al5O 12 , adding ultrapure water, adjusting the mass solid content of the slurry to 42wt.%, adding 1.0wt% of polyacrylic acid in total, adding 0.1wt% of TEOS in total, adding 0.2wt% of MgCl2 in total, and stirring all the raw materials using a high-speed disperser, with a stirring time of 60min and a stirring speed of 1000r / min; 0.98 Yb 0.02 )3Al5O 12 0.98 Yb 0.02 )3Al5O 12 0.98 Yb 0.02 )3Al5O 12

[0051] (3) Synchronous precipitation: adding 4 times the total mass of 3mm dry ice particles to the solution obtained in step (2) to obtain ice crystal precipitation, and drying the ice crystals using a freeze-drying method to obtain a highly dispersed (Y 0.98 Yb 0.02 )3Al5O 12 0.98 Yb 0.02 )3Al5O 12 mixed powder;

[0052] ​​​​(4) blank forming: the powder obtained in step (3) is calcined at a calcination temperature of 800 DEG C, and then sieved, the sieving mesh number is 100 meshes, and the sieving number is 3 times, to obtain a mixed powder for forming, the obtained powder is tablet-pressed and formed, and then cold isostatic pressed at a pressure of 200 MPa for 10 min, to obtain a ceramic blank;

[0053] (5) ceramic preparation: the obtained blank is calcined at a calcination temperature of 800 DEG C, and then vacuum sintered at a vacuum sintering temperature of 1780 DEG C for 30 h, the vacuum degree is ≤9.0*10 -3 Pa, the obtained ceramic is annealed, and then double-side polished, to obtain a Yb:YAG transparent ceramic product. As shown in FIG. 6, the light transmittance is high. Figure 6

[0054] Figure 1 FIG. 1 is a SEM image of the initial mixed powder of Example 1 of the present application, and FIG. 2 is a SEM image of the initial mixed powder of Example 2 of the present application, the powder morphology is uniform, and the dispersion state is good; 0.998 Ce 0.002 )3Al5O 12 , (b) uncalcined (Y 0.998 Nd 0.002 )3Al5O 12 , (c) calcined (Y 0.998 Ce 0.002 )3Al5O 12 , (d) calcined (Y 0.998 Nd 0.002 )3Al5O 12 The SEM images of the initial mixed powder; it can be seen from the figure that the powder morphology is uniform, and the dispersion state is good;

[0055] Figure 2 FIG. 4 is a cross-sectional SEM image of the Ce:YAG transparent ceramic prepared in Example 1 of the present application sintered at 1500 DEG C and 1600 DEG C, if segregation or molten zone is formed in the early stage of sintering, the ceramic will not be densified, as shown in the figure, the ceramic grains begin to grow, and there are a large number of interconnected pores in the blank;

[0056] Figure 3 FIG. 5 is an optical transmittance curve of the Ce:YAG transparent ceramic prepared in Example 1 of the present application, it can be seen from the figure that the sample transmittance is >80% @ 600 nm, indicating that the sample has good optical quality;

[0057] Figure 4 FIG. 6 is a sample physical map of the Ce:YAG transparent ceramic prepared in Example 1 of the present application, the text below the sample is clear, indicating that the sample has good optical quality;

[0058] ​Figure 5 SEM microstructure images of the surface (a) and cross-section (b) of the Nd:YAG transparent ceramic prepared in Example 2 of the present application;

[0059] Figure 6 Physical image and optical transmittance test results of the Yb:YAG transparent ceramic prepared in Example 3 of the present application.

[0060] Obviously, various modifications and changes can be made to the present application by those skilled in the art without departing from the spirit and scope of the present application. Thus, it is intended that the present application cover the modifications and changes as long as they come within the scope of the appended claims and their equivalents.

Claims

1. A method for preparing YAG-based transparent ceramic by using a synchronous precipitation method, characterized in that, Comprising the following steps: S1 raw material selection: Y(NO3)3.6H2O, Al(NO3)3, Re(NO3)3, MgCl2 are selected as mixed powder raw materials, ultrapure water is selected for solution preparation, and dry ice is selected as a synchronous precipitation raw material, and polyacrylic acid is selected as a dispersant; In step S1, Y(NO3)3·6H2O, Al(NO3)3, Re(NO3)3 are weighed according to the stoichiometric ratio (Y 1-x Re x )3Al5O 12 , wherein 0.01≤ x ≤0.02; Re 3+ ions are selected from Eu 3+ , Tb 3+ , Ce 3+ , Gd 3+ , Yb 3+ , Er 3+ , Nd 3+ , Sm 3+ , Pr 3+ ions. S2 solution preparation: add ultrapure water to Y(NO3)3.6H2O, Al(NO3)3, Re(NO3)3 weighed in step S1, adjust the slurry mass solid content to 34-42 wt.%, add polyacrylic acid and sintering additives, and stir uniformly; Step S2, the amount of polyacrylic acid added is Y3Al5O 12 0.1 to 1.0 wt% of the total mass; the sintering aid is a combination of both TEOS and MgCl2, the amount of TEOS added is Y3Al5O 12 0.1 to 0.8 wt% of the total mass, the amount of MgCl2 added is Y3Al5O 12 0.2 to 0.8 wt% of the total mass; S3 synchronous precipitation: add dry ice particles to the solution obtained in step S2 to obtain ice crystal precipitation, and dry the ice crystals using freeze-drying to obtain a highly dispersed mixed powder; In step S3, dry ice particles with a diameter of 3-5 mm are selected, and the amount of dry ice added is 3-5 times the mass of Y3Al5O 12 the total mass. S4 green body forming: calcine the powder obtained in step S3, then sieve, obtain a mixed powder that can be used for forming, press the obtained powder into a tablet, then cold isostatic pressing, and obtain a ceramic green body; S5 ceramic preparation: calcine the green body obtained in step S4, then vacuum sinter, anneal the obtained ceramic, then double-side polish, and obtain a YAG-based transparent ceramic product.

2. The method for preparing YAG-based transparent ceramics by synchronous precipitation according to claim 1, characterized in that, In step S1, all raw materials are commercially available high-purity raw materials.

3. The method for preparing YAG-based transparent ceramics by synchronous precipitation according to claim 1, characterized in that, In step S2, all raw materials are stirred using a high-speed disperser, the stirring time is 30-60 min, and the stirring speed is 800-1200 r / min.

4. The method for preparing YAG-based transparent ceramics by synchronous precipitation according to claim 1, characterized in that, In step S4, the calcination temperature is 500-600℃.

5. The method for preparing YAG-based transparent ceramics by synchronous precipitation according to claim 1, characterized in that, In step S4, the sieve mesh size is 100 mesh, and the sieving times are more than 3 times.

6. The method for preparing YAG-based transparent ceramics by synchronous precipitation according to claim 1, wherein, In step S4, the cold isostatic pressing pressure is 200 MPa, and the time is 5-10 min.

7. The method for preparing YAG-based transparent ceramics by synchronous precipitation according to claim 1, wherein, In step S5, the calcination temperature is 600-900 DEG C, the vacuum sintering temperature is 1760-1820 DEG C, the holding time is 8-30 h, and the vacuum degree is less than or equal to 9.0*10 -3 Pa.

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