Preparation method of transparent ceramic with YAG / Y2O3 double-crystal-phase composite structure

Abstract

The invention discloses a preparation method of YAG / Y2O3 double-crystal-phase composite structure transparent ceramic, and belongs to the technical field of advanced functional ceramic preparation. The preparation method comprises the following steps: by taking 5N nanoscale Y2O3, Al2O3 and the like as raw materials, carrying out ball milling, drying, sieving, calcining and the like to prepare YAG powder, then taking Y2O3 as a raw material to prepare Y2O3 powder, carrying out isostatic pressing and calcining on the two kinds of powder, and then carrying out vacuum sintering, annealing, polishing and the like to obtain a bicrystal phase composite YAG / Y2O3 transparent ceramic sample. According to the invention, two transparent ceramics with different crystal phase structures are compounded, the common technical problem of segregation on the interface of two crystal boundaries is solved, and integration of multiple functions such as laser gain, fluorescence emission and optical storage is realized by doping different rare earth ions in the composite ceramics.

Description

Technical Field

[0001] The invention belongs to the technical field of advanced functional ceramic preparation, and in particular relates to a method for preparing YAG / Y2O3 dual-crystal phase composite structure transparent ceramic. Background Art

[0002] Generally speaking, ceramics are opaque because the micropores and other defects inside the ceramic material refract and scatter the light, making it almost impossible for the light to pass through the ceramic body. Transparent ceramics are ceramics that can transmit light. Transparent ceramics not only have excellent light transmittance, but also have the unique high strength, high hardness, corrosion resistance, high temperature resistance and other properties of ceramics, which are far superior to general crystal and glass optical materials.

[0003] Factors that affect the light transmittance of transparent ceramics include porosity, grain boundaries, crystal structure, raw materials and second phase impurities, grain size and additives, surface finish, etc. Among them, crystal structure and secondary phase are considered to be the basis of ceramic light transmittance. The reason is that in anisotropic crystals, when light is incident from one grain to the adjacent grain, it will be scattered due to the birefringence phenomenon. In addition, the requirement for transparent ceramics is a uniform, continuous single-phase structure. Impurities and second phases in ceramics are inconsistent with the optical properties of crystals and will become scattering and absorption centers, thereby reducing the transparency of ceramics.

[0004] Therefore, to obtain highly transparent ceramics, a single crystal phase and a cubic material that is isotropic to light must be used as the basis, resulting in composite structure ceramics with high optical quality, such as YAG / Nd:YAG, Nd:YAG / Cr:YAG and other products, which are all single garnet crystal structures. There are no reports on transparent ceramics directly composited with two phases at home and abroad. Some documents disclose two-phase composite transparent ceramics such as YAG / Al2O3 and YAG / MgAl2O4, which are products prepared by welding with transparent solder.

[0005] The reason for the above phenomenon is that transparent ceramics with different crystal structures require different sintering temperatures and product shrinkage rates. Direct compounding will inevitably lead to delamination, cracking, grain boundary segregation and other problems, and it is impossible to maintain the high optical quality of the transparent ceramics themselves. Therefore, the technology of compounding transparent ceramics with different crystal phases needs to be studied. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing a YAG / Y2O3 dual-phase composite structure transparent ceramic, which adopts a wedge-shaped structure composite scheme, avoids the occurrence of segregation by pre-phase formation, and ensures the high optical quality of the two-phase composite ceramic.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing a YAG / Y2O3 dual-phase composite structure transparent ceramic, specifically comprising the following steps:

[0009] ①Use high-purity 5N nano-grade Y2O3 and Al2O3 raw materials, and follow the stoichiometric ratio of Y3Al5O 12 Weighing, adding sintering aid and dispersant, ball milling to obtain a uniformly mixed slurry;

[0010] ② Drying and sieving the slurry obtained in step ①, and calcining in an oxygen environment at a calcination temperature of 600 to 800° C. for a holding time of 6 to 10 hours;

[0011] ③ The powder obtained in step ② is vacuum roasted at a temperature of 1100° C. to 1200° C. for 2 h to 4 h; then ball milled with anhydrous ethanol as solvent, and the obtained slurry is dried and sieved;

[0012] ④ Calcine the powder obtained in step ③ in an air environment at a calcination temperature of 600°C to 800°C for 6h to 8h;

[0013] ⑤ Take commercial 5N high-purity nano Y2O3 as raw material, weigh it, add 5wt% to 10wt% zirconium carbonate as sintering aid, use anhydrous ethanol as solvent, ball mill, dry and sieve the slurry, and calcine it in oxygen environment at 800℃ for 6h to 10h;

[0014] ⑥ Pour the powder obtained in step ⑤ into a metal mold, vibrate and level it, add the powder obtained in step ④, and isostatically press to obtain a composite structure transparent ceramic blank, and calcine the obtained blank at a calcination temperature of 600° C. to 800° C. for a heat preservation time of 6 h to 10 h;

[0015] ⑦ The green body obtained in step ⑥ is subjected to vacuum sintering, and the temperature is increased to 1200℃~1300℃ at 4℃ / min~6℃ / min, and the temperature is kept for 2h~3h; the temperature is continued to be increased to 1760℃~1800℃ at a heating rate of 2℃ / min~4℃ / min, and the temperature is kept for 10h~20h; the temperature is decreased to 1200℃~1300℃ at a rate of 5℃ / min, and the temperature is kept for 10min~30min, and then the temperature is naturally decreased with the furnace;

[0016] ⑧ Anneal the sample obtained in step ⑦, and obtain a YAG / Y2O3 transparent ceramic sample of a dual-crystal phase composite by surface polishing or double-sided polishing.

[0017] Preferably, the sintering aid described in step ① is magnesium oxide with a purity of 4N, and the amount of the sintering aid added is 0.1 to 0.5 wt% of the total mass of Y2O3 and Al2O3; the dispersant is polyethyleneimine, and the amount of the dispersant added is 0.1 to 0.5 wt% of the total mass of Y2O3 and Al2O3; the YAG refers to transparent ceramics with a garnet structure, including but not limited to Ce:YAG, Nd:YAG, Yb:YAG, Cr:YAG, Ho:YAG, etc.

[0018] Preferably, the ball milling speed in step ① is 160 r / min to 180 r / min, and the ball milling time is 15 h to 30 h.

[0019] Preferably, the drying oven temperature in step ② is 120° C. to 150° C., the drying is performed for 15 to 24 hours, the sieve mesh is 100 to 200 mesh, and the sieving is performed 3 times.

[0020] Preferably, the vacuum roasting in step ③ has a roasting vacuum degree lower than 6.67×10 -3 Pa.

[0021] Preferably, the ball milling speed in step ③ is 200 r / min to 240 r / min, and the ball milling time is 4 h.

[0022] Preferably, the drying temperature in step ③ is 55° C. to 80° C., the drying is performed for 24 to 48 hours, the sieving mesh is 100 to 200 mesh, and the sieving is performed 3 times.

[0023] Preferably, the Y2O3 sesquioxide system transparent ceramics described in step ⑤ include but are not limited to: Ce:Y2O3, Nd:Y2O3, Yb:Y2O3, etc.

[0024] Preferably, the ball milling speed in step ⑤ is 160 r / min to 180 r / min, and the ball milling time is 15 h to 30 h.

[0025] Preferably, the drying temperature in step ⑤ is 55° C. to 80° C., the drying time is 24 h to 48 h, the sieving mesh size is 100 mesh to 200 mesh, and the sieving is performed 3 times.

[0026] Preferably, the isostatic pressure in step ⑥ is 200 MPa, and the pressure is maintained for 5 min to 15 min.

[0027] Preferably, the annealing temperature in step ⑧ is 1000° C. to 1150° C., and the annealing time is 10 h to 30 h.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The YAG / Y2O3 dual-phase composite structure transparent ceramic disclosed in the present invention realizes the composite of transparent ceramics belonging to two different crystal phase structures, solves the common technical problem of segregation at the interface of two grain boundaries, and contributes a new solution to the design and preparation of composite structure transparent ceramics. The composite strategy of the present invention provides the possibility for the multifunctional integration of transparent ceramics. By doping different rare earth ions in the composite ceramics at the same time, the integration of multiple functions such as laser gain, fluorescence emission, and optical storage is realized, which expands the space for the application of transparent ceramics.

[0030] 2. Compared with the existing two-phase transparent ceramics welded by hot bonds or transparent solder, the transparent ceramics prepared by the present invention are based on the composite of microstructures, which increases the bonding force between crystals, making the ceramic material less likely to break or be damaged when subjected to external forces, thereby improving the reliability and durability of the material; in addition, the thermal expansion coefficient of YAG is relatively low, and after being composited with Y2O3, the thermal expansion coefficient of the material can be adjusted to make it closer to the needs of practical applications. A suitable thermal expansion coefficient can reduce the thermal stress generated by the material during temperature changes, and reduce the risk of the material breaking or being damaged due to thermal stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Transmittance curve of the sample of Example 1.

[0032] Figure 2 Actual photo of the six-sided polishing process of the sample in Example 1.

[0033] Figure 3 SEM images of the thermally etched surfaces of the samples of Example 2 and Example 3. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0035] Example 1

[0036] ①Use high-purity 5N nano-grade Y2O3 and Al2O3 raw materials, and follow the stoichiometric ratio of Y3Al5O 12 Weighing, adding 0.1wt% of the total mass of Y2O3 and Al2O3 as a sintering aid magnesium oxide, adding 0.1wt% of the total mass of Y2O3 and Al2O3 as a dispersant polyethyleneimine, and then planetary ball milling at a ball milling speed of 180r / min for 15h to obtain a uniformly mixed slurry;

[0037] ② Dry the slurry obtained in step ① in a blast drying oven at 120° C. for 24 h; sieve the dried powder to 100 mesh for 3 times, and then calcine at 600° C. for 10 h in an oxygen environment;

[0038] ③ The powder obtained in step ② was vacuum calcined at a temperature of 1100°C and a vacuum degree of 6.67×10 - 3 Pa, the heat preservation time is 2h; then the obtained powder is ball-milled, using anhydrous ethanol as the solvent, the ball milling speed is 240r / min, and the ball milling time is 4h; then the obtained slurry is dried, the drying temperature is 55℃, and the drying time is 24h, and the dried powder is sieved, the sieve mesh number is 100 mesh, and sieved 3 times;

[0039] ④ Calcine the powder obtained in step ③ at a temperature of 600°C for 6 hours in an air atmosphere;

[0040] ⑤ Use commercial 5N high-purity nano Y2O3 as raw material and weigh it, add 5wt% zirconium carbonate as sintering aid, and then perform planetary ball milling, use anhydrous ethanol as solvent, the ball milling speed is 160r / min, the ball milling time is 15h, and then dry the obtained slurry at a drying temperature of 55°C for 24h, sieve the dried powder with a sieve mesh of 200 mesh and sieve 3 times; then calcine at a calcination temperature of 800°C in an air atmosphere for 6h;

[0041] ⑥ Pour the powder obtained in step ⑤ into a metal mold, vibrate and level it, add the powder obtained in step ④, and then perform isostatic pressing at an isostatic pressing pressure of 200 MPa for 5 minutes to obtain a composite structure transparent ceramic blank, and calcine the obtained blank at a calcination temperature of 600°C for 10 hours;

[0042] ⑦ The green body obtained in step ⑥ was subjected to vacuum sintering, and the temperature was raised to 1200°C at a rate of 4°C / min, and kept at this temperature for 2 hours; the temperature was continued to be raised to 1760°C at a rate of 2°C / min, and kept at this temperature for 10 hours; the temperature was lowered to 1200°C at a rate of 5°C / min, and kept at this temperature for 10 minutes, and then the temperature was naturally lowered along with the furnace;

[0043] ⑧ Anneal the sample obtained in step ⑦ at a temperature of 1000° C. for 30 h, and polish the sample on 6 sides to obtain a twin-phase composite YAG / Y2O3 transparent ceramic.

[0044] Figure 1 This is the transmittance curve of the sample in Example 1. It can be seen from the figure that the composite structure ceramic has good optical transmittance.

[0045] Figure 2 This is a real picture of the six-sided polishing of the sample in Example 1. It can be seen that the sample is transparent and bright, has no composite interface, and has good optical quality.

[0046] Example 2

[0047] ①Use high-purity 5N nano-grade Y2O3, Al2O3, CeO2 as raw materials and follow the stoichiometric ratio (Y0 .995 Ce 0.005 )3Al5O 12 Weighing, adding 0.3wt% of the total mass of Y2O3, CeO2 and Al2O3 as a sintering aid magnesium oxide, adding 0.5wt% of the total mass of Y2O3, CeO2 and Al2O3 as a dispersant polyethyleneimine, and then performing planetary ball milling at a ball milling speed of 180r / min for 15h to obtain a uniformly mixed slurry;

[0048] ② Dry the slurry obtained in step ① in a blast drying oven at 150° C. for 24 h; sieve the dried powder to 200 meshes for 3 times, and then calcine at 800° C. for 10 h in an oxygen environment;

[0049] ③ The powder obtained in step ② was vacuum calcined at a temperature of 1200°C and a vacuum degree of 6.67×10 - 3 Pa, the heat preservation time is 4h; then the obtained powder is ball-milled, using anhydrous ethanol as the solvent, the ball milling speed is 240r / min, and the ball milling time is 4h; then the obtained slurry is dried, the drying temperature is 55°C, and the drying time is 48h. The dried powder is sieved, the sieve mesh number is 200 mesh, and it is sieved 3 times;

[0050] ④ calcining the powder obtained in step ③ at a temperature of 600°C to 800°C for 6h to 8h in an air atmosphere;

[0051] ⑤ Use commercial 5N high-purity nano Y2O3 as raw material and weigh it, add 10wt% zirconium carbonate of Y2O3 mass as sintering aid, and then perform planetary ball milling, use anhydrous ethanol as solvent, the ball milling speed is 180r / min, the ball milling time is 30h, and then dry the obtained slurry at a drying temperature of 55°C for 48h, sieve the dried powder with a sieve mesh of 200 mesh and sieve 3 times; then calcine at a calcination temperature of 800°C for 6h in an air atmosphere;

[0052] ⑥ Pour the powder obtained in step ⑤ into a metal mold, vibrate and level it, add the powder obtained in step ④, and then perform isostatic pressing at an isostatic pressing pressure of 200 MPa for 15 minutes to obtain a composite structure transparent ceramic blank, and calcine the obtained blank at a calcination temperature of 800°C for 10 hours;

[0053] ⑦ The green body obtained in step ⑥ was subjected to vacuum sintering, and the temperature was raised to 1300°C at a rate of 6°C / min, and kept at this temperature for 3 hours; the temperature was continued to be raised to 1800°C at a rate of 4°C / min, and kept at this temperature for 20 hours; the temperature was lowered to 1300°C at a rate of 5°C / min, and kept at this temperature for 30 minutes, and then the temperature was naturally lowered along with the furnace;

[0054] ⑧ Anneal the sample obtained in step ⑦ at a temperature of 1150° C. for 30 h, and obtain a twin-phase composite YAG / Y2O3 transparent ceramic sample by double-sided polishing.

[0055] Example 3

[0056] ①Use high-purity 5N nano-grade Y2O3 and Al2O3 raw materials, and follow the stoichiometric ratio of Y3Al5O 12 Weighing, adding 0.3wt% of the total mass of Y2O3 and Al2O3 as a sintering aid magnesium oxide, adding 0.3wt% of the total mass of Y2O3 and Al2O3 as a dispersant polyethyleneimine, and then planetary ball milling at a ball milling speed of 170r / min for 24h to obtain a uniformly mixed slurry;

[0057] ② Dry the slurry obtained in step ① in a blast drying oven at 150° C. for 20 h; sieve the dried powder to 200 meshes for 3 times, and then calcine at 700° C. for 8 h in an oxygen environment;

[0058] ③ The powder obtained in step ② was vacuum roasted at a temperature of 1150°C and a vacuum degree of 8×10 -4 Pa, the heat preservation time is 4h; then the obtained powder is ball-milled, using anhydrous ethanol as the solvent, the ball milling speed is 240r / min, and the ball milling time is 4h; then the obtained slurry is dried, the drying temperature is 70℃, and the drying time is 30h, and the dried powder is sieved, the sieve mesh number is 200 mesh, and sieved 3 times;

[0059] ④ Calcine the powder obtained in step ③ at a temperature of 800°C for 6 hours in an air atmosphere;

[0060] ⑤ Use commercial 5N high-purity nano Y2O3 and CeO2 as raw materials, and weigh them according to the molar wave Y2O3:CeO2 of 99:1, add 10wt% of zirconium carbonate as a sintering aid, and then perform planetary ball milling, use anhydrous ethanol as solvent, the ball milling speed is 180r / min, the ball milling time is 20h, and then dry the obtained slurry at a drying temperature of 75°C for 30h, sieve the dried powder with a sieve mesh of 200 mesh and sieve 3 times; then calcine at a calcination temperature of 800°C for 10h in an air atmosphere;

[0061] ⑥ Pour the powder obtained in step ⑤ into a metal mold, vibrate and level it, add the powder obtained in step ④, and then perform isostatic pressing at an isostatic pressing pressure of 200 MPa for 15 minutes to obtain a composite structure transparent ceramic blank, and calcine the obtained blank at a calcination temperature of 600° C. for 10 hours;

[0062] ⑦ The green body obtained in step ⑥ is subjected to vacuum sintering, and the temperature is raised to 1250°C at a rate of 5°C / min, and kept at this temperature for 3 hours; the temperature is further raised to 1800°C at a rate of 2°C / min, and kept at this temperature for 20 hours; the temperature is lowered to 1250°C at a rate of 5°C / min, and kept at this temperature for 20 minutes, and then the temperature is naturally lowered along with the furnace;

[0063] ⑧ Anneal the sample obtained in step ⑦ at a temperature of 1150° C. for 10 h, and obtain a twin-phase composite YAG / Y2O3 transparent ceramic sample by double-sided polishing.

[0064] The SEM images of the thermally etched surfaces of the samples of Example 2 and Example 3 are shown in FIG. Figure 3 As shown in the figure, it can be seen that no segregation is observed at the interface, and there are no intracrystalline or intercrystalline pores on the thermally etched surface, indicating that the sample has good optical quality.

[0065] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for preparing YAG / Y2O3 dual-phase composite structure transparent ceramics, characterized in that: The method specifically comprises the following steps: ①Use high-purity 5N nano-grade Y2O3 and Al2O3 raw materials, and follow the stoichiometric ratio of Y3Al5O 12 Weighing, adding sintering aid and dispersant, ball milling to obtain a uniformly mixed slurry; ② Drying and sieving the slurry obtained in step ①, and calcining in an oxygen environment at a calcination temperature of 600 to 800° C. for a holding time of 6 to 10 hours; ③ The powder obtained in step ② is vacuum roasted at a temperature of 1100° C. to 1200° C. for 2 h to 4 h; then ball milled with anhydrous ethanol as solvent, and the obtained slurry is dried and sieved; ④ Calcine the powder obtained in step ③ in an air environment at a calcination temperature of 600°C to 800°C for 6h to 8h; ⑤ Select commercial 5N high-purity nano Y2O3 as raw material, weigh it, add 5wt% to 10wt% zirconium carbonate as sintering aid, use anhydrous ethanol as solvent, ball mill, dry and sieve the obtained slurry, calcine in air environment, calcination temperature is 800℃, keep warm for 6h to 10h; ⑥ Pour the powder obtained in step ⑤ into a metal mold, vibrate and level it, add the powder obtained in step ④, and isostatically press to obtain a composite structure transparent ceramic blank, and calcine the obtained blank at a calcination temperature of 600° C. to 800° C. for a heat preservation time of 6 h to 10 h; ⑦ The green body obtained in step ⑥ is subjected to vacuum sintering, and the temperature is increased to 1200℃~1300℃ at 4℃ / min~6℃ / min, and the temperature is kept for 2h~3h; the temperature is continued to be increased to 1760℃~1800℃ at a heating rate of 2℃ / min~4℃ / min, and the temperature is kept for 10h~20h; the temperature is decreased to 1200℃~1300℃ at a rate of 5℃ / min, and the temperature is kept for 10min~30min, and then the temperature is naturally decreased with the furnace; ⑧ Anneal the sample obtained in step ⑦, and obtain a YAG / Y2O3 transparent ceramic sample of a dual-crystal phase composite by surface polishing or double-sided polishing.

2. The method for preparing a YAG / Y2O3 dual-phase composite structure transparent ceramic according to claim 1, characterized in that: The YAG refers to a transparent ceramic with a garnet structure, including but not limited to Ce:YAG, Nd:YAG, Yb:YAG, Cr:YAG, Ho:YAG and the like.

3. The method for preparing a YAG / Y2O3 dual-phase composite structure transparent ceramic according to claim 1, characterized in that: The sintering aid described in step ① is magnesium oxide with a purity of 4N, and the amount of the sintering aid added is 0.1-0.5wt% of the total mass of Y2O3 and Al2O3; the dispersant is polyethyleneimine, and the amount of the dispersant added is 0.1-0.5wt% of the total mass of Y2O3 and Al2O3.

4. The method for preparing a YAG / Y2O3 dual-phase composite structure transparent ceramic according to claim 1, characterized in that: The ball milling speed in step ① is 160 r / min to 180 r / min, and the ball milling time is 15 h to 30 h.

5. The method for preparing a YAG / Y2O3 dual-phase composite structure transparent ceramic according to claim 1, characterized in that: The vacuum calcination in step ③ has a calcination vacuum degree lower than 6.67×10 -3 Pa.

6. The method for preparing a YAG / Y2O3 dual-phase composite structure transparent ceramic according to claim 1, characterized in that: The ball milling speed in step ③ is 200 r / min to 240 r / min, and the ball milling time is 4 h.

7. The method for preparing a YAG / Y2O3 dual-phase composite structure transparent ceramic according to claim 1, characterized in that: The Y2O3 described in step ⑤ refers to sesquioxide system transparent ceramics, including but not limited to: Ce:Y2O3, Nd:Y2O3, Yb:Y2O3, etc.

8. The method for preparing a YAG / Y2O3 dual-phase composite structure transparent ceramic according to claim 1, characterized in that: The ball milling speed in step ⑤ is 160 r / min to 180 r / min, and the ball milling time is 15 h to 30 h.

9. The method for preparing a YAG / Y2O3 dual-phase composite structure transparent ceramic according to claim 1, characterized in that: The isostatic pressure in step ⑥ is 200 MPa, and the pressure is maintained for 5 to 15 minutes.

10. The method for preparing a YAG / Y2O3 dual-phase composite structure transparent ceramic according to claim 1, characterized in that: The annealing temperature in step ⑧ is 1000° C. to 1150° C., and the annealing time is 10 h to 30 h.

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