CN100360469C - Double doped yttrium aluminum garnet transparent ceramic material and preparation method - Google Patents

Abstract

The present invention relates to a double-doped yttrium aluminum garnet transparent ceramic material and a preparation method, which is characterized in that 1) for Cr ⁴⁺ , Nd ³⁺ :YAG system, the doping amount of Cr ions is 0.02-0.5 at%, and the doping amount of Nd ions 2) For the Cr ⁴⁺ , Yb ³⁺ :YAG system, the doping amount of Cr ions is 0.01-0.5 at%, and the doping amount of Yb ions is 5-30 at%. The preparation method is characterized in that the green body formed by dry pressing, cooling and isostatic pressing after uniform mixing of powder materials is directly sintered in a vacuum sintering furnace or sintered in two steps, and then annealed after sintering. The double-doped transparent YAG material provided by the invention has a transmittance greater than 70%, and can be used as a working material of a self-Q-switching solid-state laser.

Description

Double doped yttrium aluminum garnet transparent ceramic material and preparation method

technical field

The present invention relates to double-doped yttrium aluminum garnet transparent ceramics and its preparation method, more precisely to Cr ⁴⁺ , Nd ³⁺ : YAG and Cr ⁴⁺ , Yb ³⁺ : YAG self-Q-switching laser transparent ceramics and its preparation method The invention belongs to the technical field of laser transparent ceramic material preparation.

Background technique

The optoelectronic industry is an important pillar industry in the 21st century, and laser technology is the core component of optoelectronic technology. As the main body of solid-state lasers, laser materials are an important pillar of solid-state laser technology. At present, the Nd:YAG laser materials on the market are all single crystals. Due to their long growth cycle, high price, small size, and low doping concentration, their performance and application range are limited. For many years, scientific researchers have tried to use glass and glass ceramics as laser working materials to replace single crystals. Glass, although easily made in large sizes, has an order of magnitude lower thermal conductivity than single crystals. Glass-ceramic is a heterogeneous material with a very low (even negative) thermal expansion coefficient and good thermal shock resistance, but the laser efficiency is not satisfactory compared with single crystal materials. Scientists have tried to use Dy:CaF ₂ , NDY and other polycrystalline ceramics as working materials for solid-state lasers since the 1960s, but the results were not satisfactory. Since the publication of patents JP05-286761, JP05-286762, JP05-294722, JP05-294723, JP05-294722, and JP05-235462, Nd: YAG transparent polycrystalline ceramics have attracted great interest as laser working materials. Nd: Solid-state lasers with YAG transparent ceramics as the working material are also developing towards high power and high efficiency. Nd:YAG transparent ceramics are likely to become competitive laser materials used to replace single crystals.

Nd:YAG single crystal has excellent mechanical, optical and chemical thermal stability, so the passive Q-switched gain medium of LD pump is usually Nd:YAG single crystal. Cr ⁴⁺ : YAG crystal is an ideal material for passive Q-switching switch. Due to its large absorption cross-section at 1 μm, it is an important saturable absorber for Nd lasers. Double-doped Cr ⁴⁺ , Nd ³⁺ : YAG crystal is a kind of Self-Q-tuning switch material with excellent performance. Compared with laser transparent ceramics doped with Nd ³⁺ , YAG transparent ceramics doped with Yb ³⁺ has small quantum defects and can achieve high concentration doping of Yb ³⁺ without substantially reducing its fluorescence lifetime. Nd ³⁺ is better, using Cr ⁴⁺ :YAG as a passive Q-switched switch to realize the passive Q-switched output of Yb:YAG crystal. At the same time, it has been reported that the Shanghai Institute of Optics and Mechanics, Chinese Academy of Sciences has grown co-doped Cr ⁴⁺ , Yb ³⁺ :YAG single crystals, and achieved self-Q-switching laser output.

From the research status and progress of Nd:YAG laser transparent ceramics and Cr ⁴⁺ , Nd ³⁺ : YAG and Cr ⁴⁺ , Yb ³⁺ : YAG single crystal, double-doped Cr ⁴⁺ , Nd ³⁺ : YAG and Cr ⁴⁺ , Yb ³⁺ : YAG transparent ceramics will have great strength and commercial potential as self-Q-switched microchip lasers. At the same time, Cr ⁴⁺ , Yb ³⁺ : YAG transparent ceramics will be of great significance to realize the high efficiency, high power, integration, miniaturization, compact structure and practical use of passive Q-switched lasers.

Contents of the invention

The object of the present invention is to provide two kinds of double-doped yttrium aluminum garnet transparent ceramics and preparation methods, specifically related to Cr ⁴⁺ , Nd ³⁺ : YAG and Cr ⁴⁺ , Yb ³⁺ : YAG transparent ceramics and their preparation The method is expected to realize self-Q-switching laser output.

The preparation method of the present invention is as shown in Figure 1, comprises the selection of raw material and sintering aid, ball mill mixing, drying, forming, vacuum sintering and annealing treatment and other technological processes, each technological process is characterized in that:

(1) Raw materials can be:

(a) Commercial high-purity α-Al ₂ O ₃ , Y ₂ O ₃ , Cr ₂ O ₃ , Nd ₂ O ₃ and Yb ₂ O ₃ powders;

(b) Commercial high-purity γ-Al ₂ O ₃ , Y ₂ O ₃ , Cr ₂ O ₃ , Nd ₂ O ₃ and Yb ₂ O ₃ powders;

(c) Commercial high-purity α-Al ₂ O ₃ , γ-Al ₂ O ₃ , Y ₂ O ₃ , Cr ₂ O ₃ , Nd ₂ O ₃ and Yb ₂ O ₃ powders;

(d) High-purity α-Al ₂ O ₃ , Cr ₂ O ₃ , Nd ₂ O ₃ , Yb ₂ O ₃ and wet chemical methods (including precipitation method, sol-gel method, combustion synthesis method, etc.) Pure Y ₂ O ₃ nano powder;

(e) Commercial high-purity γ-Al ₂ O ₃ , Cr ₂ O ₃ , Nd ₂ O ₃ , Yb ₂ O ₃ and high-purity Y ₂ O prepared by wet chemical methods (including precipitation method, sol-gel method, etc.) ₃ nanometer powder;

(f) Commercial high-purity Y ₂ O ₃ , Cr ₂ O ₃ , Nd ₂ O ₃ , Yb ₂ O ₃ and high-purity Al ₂ O ₃ nanometer prepared by wet chemical method (including precipitation method, sol-gel method, etc.) Powder;

(g) High-purity Al ₂ O ₃ , Y ₂ O ₃ nanopowders and commercial high-purity Cr ₂ O ₃ , Nd ₂ O ₃ , Yb ₂ O ₃ prepared by wet chemical method (including precipitation method or sol-gel method) Powder;

(h) Y ₂ O ₃ wrapped Al ₂ O ₃ powder and commercial high-purity Cr ₂ O ₃ , Nd ₂ O ₃ , Yb ₂ O ₃ powder prepared by heterogeneous precipitation method;

(i) Al ₂ O ₃ wrapped Y ₂ O ₃ powder and commercial high-purity Cr ₂ O ₃ , Nd ₂ O ₃ , Yb ₂ O ₃ powder prepared by heterogeneous precipitation method;

(j) High-purity YAG nanopowder and commercial high-purity Cr ₂ O ₃ , Nd ₂ O ₃ , Yb ₂ O ₃ powder prepared by wet chemical method (including precipitation method or sol-gel method, etc.);

(k) High-purity Nd:YAG and Yb:YAG nanopowders and commercial high-purity Cr ₂ O ₃ powders prepared by wet chemical method (including precipitation method or sol-gel method, etc.).

(2) The added sintering aid can be one or both of Li ₂ O, Na ₂ O, K ₂ O, CaO, MgO, SiO ₂ and TEOS (tetraethyl silicate). The addition of sintering aid The amount is 10 ² to 10 ⁶ ppm.

The commercial raw materials mentioned above have a purity of 99.95-99.99%, and are weighed and mixed according to the doping ratio.

(3) Ball milling mixing process:

(a) The ball mill tank is made of polytetrafluoroethylene or high-purity alumina ceramic material;

(b) High-purity agate balls, high-purity zirconia ceramic balls or high-purity alumina ceramic balls are used for grinding balls;

(c) The ball milling medium uses absolute ethanol or deionized water;

(d) Using a planetary ball mill, the rotating speed is 100-400 rpm, and the ball milling time is 2-20 hours.

(4) The slurry mixed by ball milling is dried in an oven at 90-100° C., and ground through a 100-mesh sieve.

(5) Forming process:

(a) The axial one-way pressure method adopted in the dry pressing process, the pressure is 50-100MPa, and the pressure-holding time is 0.5-3 minutes;

(b) After the green body after dry pressing is vacuum-packed, it is formed by cold isostatic pressing under a pressure of 200-400 MPa, and the holding time is 1-5 minutes, so that the density of the green body is 45-65% of the theoretical density of the components .

(6) In the vacuum sintering process:

(a) Vacuum sintering can be directly carried out on the biscuit formed by dry pressing and cold isostatic pressing, the heating rate is 1-20°C/mim, the sintering temperature is 1650-1850°C, the holding time is 5-40 hours, and the vacuum degree is 10 ^-2 ~ 10 ^-4 Pa;

(b) Alternatively, the biscuit formed by dry pressing and cold isostatic pressing can be sintered in two steps in a vacuum furnace. The first step is to pre-fire at 1000-1500°C for 2-20 ^hours , the heating rate is 1-20°C/mim, and the vacuum degree is ^10-2-10-4 Pa; the second and second steps are at 1700-1850°C for 5-40 hours, the heating rate is 1-20°C/min, and the vacuum degree is 10 ^-2 -10 ^-4 Pa;

(c) Alternatively, the dry-pressed and cooled isostatic-pressed blank can be subjected to pressureless pre-sintering in a silicon-molybdenum rod furnace with an oxidative atmosphere: the heating rate is 1-20°C/mim, and the sintering temperature is 800-1200°C , the pre-sintering time is 2-20 hours; put the pre-sintered green body in a vacuum sintering furnace for secondary sintering, the sintering temperature is 1650-1850°C, the holding time is 5-40 hours, and the vacuum degree is 10 ^-2 ~10 ^-4 Pa. The key to sintering is to eliminate pores, develop grains, and prevent pores from being wrapped by grains.

(7) Anneal the vacuum-sintered Cr, Nd:YAG and Cr, Yb:YAG ceramics in a silicon-molybdenum rod furnace with an oxidative atmosphere: the annealing temperature is 800-1600°C, and the annealing time is 2-40 hours. Eliminate carbon impurities and oxygen defects. Finally, the vacuum sintered Cr, Nd:YAG and Cr, Yb:YAG ceramics are ground and polished.

The relative density of the obtained vacuum sintered Cr, Nd:YAG and Cr, Yb:YAG ceramic body is greater than 99.9%, and the average grain size is 1-100 μm.

The specific components of the double-doped yttrium aluminum garnet transparent ceramic provided by the present invention are:

(1) For the Cr ⁴⁺ , Nd ³⁺ :YAG system, the doping amount of Cr ions is 0.02-0.5 at%, and the doping amount of Nd ions is 0.5-4.0 at%. The doping amount is 0.05-0.1at% and 0.5-1.5at% respectively;

(2) For the Cr ⁴⁺ , Yb ³⁺ :YAG system, the doping amount of Cr ions is 0.01-0.5 at%, and the doping amount of Yb ions is 5-30 at%. The preferred doping amount of Cr ions and Yb ions is The impurity amounts are 0.01-0.1 at% and 5-10 at% respectively.

According to the process of the present invention, double-doped Cr ⁴⁺ , Nd ³⁺ : YAG, Cr ⁴⁺ , Yb ³⁺ : YAG transparent ceramics with high linear transmittance (>70%) and good mechanical properties at 1064nm laser wavelength can be prepared. It can be used as the working substance of self-Q-switching solid-state lasers.

Description of drawings

Fig. 1 is the process flow of double yttrium-doped aluminum garnet transparent ceramic provided by the present invention.

Fig. 2 The photo of 0.1at% Cr ⁴⁺ , 1.0at% Nd ³⁺ : YAG ceramic 1mm piece after polishing.

Fig. 3 is the transmittance curve of 0.1 at% Cr ⁴⁺ , 1.0 at% Nd ³⁺ :YAG ceramic provided in Example 1.

Fig. 4 is a physical photo of 0.025at% Cr ⁴⁺ , 5.0at% Yb ³⁺ :YAG ceramic 1mm piece after polishing.

Fig. 5 is the fracture morphology of 0.025 at% Cr ⁴⁺ , 5.0 at% Yb ³⁺ :YAG ceramic prepared in Example 16.

Detailed ways

Example 1:

25.4645g of α-Al ₂ O ₃ powder with a purity of 99.99%, 33.4778g of Y ₂ O ₃ powder with a purity of 99.99%, 0.5047g of Nd ₂ O ₃ powder with a purity of 99.95%, 0.0280g of a purity of 99.99 % CaO powder, 0.0380g purity of 99.99% Cr ₂ O ₃ powder and 0.2976g high-purity TEOS are put into a polytetrafluoroethylene ball mill jar, add high-purity agate ball 180g, absolute ethanol 22ml, and then ball mill for 10 Hour. After drying in an oven at 90°C, it was ground through a 100-mesh sieve. Use 100MPa pressure to press axially and unidirectionally, press it into a Φ20 disc, and then cold isostatic press under 300MPa pressure to further increase the density of the green body. Sintering is carried out in a vacuum sintering furnace, and the sample is placed in a molybdenum crucible. The heating rate of the furnace is: 30°C/min from room temperature to 1150°C, 10°C/min from 1150°C to 1780°C, and 10 hours at 1780°C. From 1780°C to 1500°C, the temperature is lowered at 5°C/min, and below 1500°C, it is cooled with the furnace. Finally, the ceramics were ground and polished to a thickness of 1 mm with a surface grinder and diamond paste. The relative density of the sintered ceramics is >99.9%. The photo of the 1mm piece of 0.1at% Cr ⁴⁺ , 1.0at% Nd ³⁺ :YAG ceramics after polishing is shown in Figure 2, and the transmittance curve is shown in Figure 3. At the laser wavelength (1064nm), the linear transmittance is as high as 71%.

The 0.1at% Cr ⁴⁺ , 1.0at% Nd ³⁺ :YAG ceramics obtained by sintering under the same conditions are annealed. After one hour, it is cooled to 450°C at 1°C/min, and then cooled with the furnace. The annealed ceramics were ground and polished to 1 mm thickness with a surface grinder and diamond paste.

Example 2:

25.4645g of α-Al ₂ O ₃ powder with a purity of 99.99%, 33.4778g of Y ₂ O ₃ powder with a purity of 99.99%, 0.5047g of Nd ₂ O ₃ powder with a purity of 99.95%, 0.0280g of a purity of 99.99 % CaO powder, 0.0380g purity of 99.99% Cr ₂ O ₃ powder and 0.2976g high-purity TEOS are put into a polytetrafluoroethylene ball mill jar, add high-purity agate ball 180g, absolute ethanol 22ml, and then ball mill for 10 Hour. After drying in an oven at 90°C, it was ground through a 100-mesh sieve. Use 100MPa pressure to press axially and unidirectionally, press it into a Φ20 disc, and then cold isostatic press under 300MPa pressure to further increase the density of the green body. Sintering is carried out in a vacuum sintering furnace, and the sample is placed in a molybdenum crucible. The heating mechanism of the furnace is: 30°C/min from room temperature to 1200°C, 10°C/min from 1200°C to 1770°C, and 30 hours at 1770°C. From 1770°C to 1500°C, the temperature is lowered at 5°C/min, and below 1500°C, it is cooled with the furnace. Finally, the ceramics were ground and polished to a thickness of 1 mm with a surface grinder and diamond paste. The relative density of the sintered ceramic is >99.9%, the transmittance of the 0.1at% Cr ⁴⁺ , 1.0at% Nd ³⁺ :YAG ceramic after polishing is greater than 70%, and the grain size is tens of microns.

Example 3:

25.4645g of α-Al ₂ O ₃ powder with a purity of 99.99%, 33.4778g of Y ₂ O ₃ powder with a purity of 99.99%, 0.5047g of Nd ₂ O ₃ powder with a purity of 99.95%, 0.0280g of a purity of 99.99 % CaO powder, 0.0380g purity of 99.99% Cr ₂ O ₃ powder and 0.2976g high-purity TEOS are put into a polytetrafluoroethylene ball mill jar, add high-purity agate ball 180g, absolute ethanol 22ml, and then ball mill for 10 Hour. After drying in an oven at 90°C, it was ground through a 100-mesh sieve. Use 100MPa pressure to press axially and unidirectionally, press it into a Φ20 disc, and then cold isostatic press under 300MPa pressure to further increase the density of the green body. The biscuit is pre-sintered in a silicon carbide rod furnace at 800°C, and the heating rate is 5°C/min. Then the pre-sintered body continues to be sintered in a vacuum sintering furnace, and the sample is placed in a molybdenum crucible. The heating rate of the furnace is: 30°C/min from room temperature to 1200°C, 5°C/min from 1200°C to 1750°C, and 30 hours at 1750°C. From 1750°C to 1000°C, the temperature is lowered at 5°C/min, and below 1500°C, it is cooled with the furnace. Finally, the ceramics were ground and polished to a thickness of 1 mm with a flat grinder and diamond paste. The relative density of the sintered ceramic is >99.9%, the transmittance of the 0.1at% Cr ⁴⁺ , 1.0at% Nd ³⁺ :YAG ceramic after polishing is greater than 70%, and the grain size is tens of microns.

Example 4: Weigh 25.44849g of α-Al ₂ O ₃ powder with a purity of 99.99%, 33.5004g of Y ₂ O ₃ powder with a purity of 99.99%, 0.5047g of Nd ₂ O ₃ powder with a purity of 99.95%, 0.0168g of CaO powder with a purity of 99.99%, 0.0076g of Cr ₂ O ₃ powder with a purity of 99.99% and 0.2976g of high-purity TEOS, mixed by ball milling, drying, sieving, green body molding, sintering, annealing, grinding, The polishing treatment process is the same as that of Example 1 to obtain 0.02 at% Cr ⁴⁺ , 1.0 at% Nd ³⁺ :YAG transparent ceramics. The relative density of the ceramic is more than 99.9%, the linear transmittance at the laser wavelength (1064nm) is as high as 70%, and the average grain size is tens of microns.

Example 5: Weigh 25.3626g of α-Al ₂ O ₃ powder with a purity of 99.99%, 33.4778g of Y ₂ O ₃ powder with a purity of 99.99%, and 0.5047g of Nd ₂ O ₃ powder with a purity of 99.95%, 0.0280g of CaO powder with a purity of 99.99%, 0.1900g of Cr ₂ O ₃ powder with a purity of 99.99%, and 0.2978g of high-purity TEOS. Other processes were the same as in Example 1 to obtain 0.5at%Cr ⁴⁺ , 1.0at% Nd ³⁺ : YAG transparent ceramics. The relative density of the ceramic is more than 99.9%, the linear transmittance at the laser wavelength (1064nm) is as high as 65%, and the average grain size is tens of microns.

Example 6: Weigh 25.4645g of α-Al ₂ O ₃ powder with a purity of 99.99%, 33.4778g of Y ₂ O ₃ powder with a purity of 99.99%, and 0.5047g of Nd ₂ O ₃ powder with a purity of 99.95%, 0.0202g of MgO powder with a purity of 99.99%, 0.0380g of Cr ₂ O ₃ powder with a purity of 99.99%, and 0.2975g of high-purity TEOS. Other processes were the same as in Example 1 to obtain 0.1at%Cr ⁴⁺ , 1.0at% Nd ³⁺ : YAG transparent ceramics.

Example 7: 25.4645g of γ-Al ₂ O ₃ powder with a purity of 99.99%, the addition amount of Y ₂ O ₃ , Nd ₂ O ₃ , CaO, Cr ₂ O ₃ high-purity TEOS is the same as that of Example 1, ball milling and mixing , drying and sieving and the biscuit molding process are all the same as in Example 1. Sintering was also carried out in a vacuum sintering furnace, and the sample was placed in a molybdenum crucible. The heating mechanism of the furnace is the same as that of Example 1. The holding time at 1800°C is 30 hours, then the temperature is lowered from 1800°C to 1200°C at 5°C/min, and the furnace cools below 1200°C. The final grinding, polishing and annealing process is the same as that of Example 1, and finally a 0.1 at% Cr ⁴⁺ , 1.0 at% Nd ³⁺ :YAG transparent ceramic is obtained.

Example 8: 20.3716g of α-Al ₂ O ₃ powder with a purity of 99.99%, 5.0929g of γ-Al ₂ O ₃ powder with a purity of 99.99%, Y ₂ O ₃ , Nd ₂ O ₃ , CaO, The addition amount of Cr ₂ O ₃ and high-purity TEOS powder is the same as in Example 1, and the other processes are the same as in Example 1.

Example 9: Weigh 169.6220g of spectroscopically pure Y(NO ₃ ) ₃ 6H ₂ O and 105.0305g of spectroscopically pure NH ₄ HCO ₃ , and configure them into 0.15M Y(NO ₃ ) ₃ solution and 2.0M NH ₄ HCO ₃ solution. Slowly add 0.15M Y(NO ₃ ) ₃ solution dropwise to 2.0M NH ₄ HCO ₃ solution while stirring at room temperature, the obtained white precipitate is aged for 12 hours and washed 3 times with deionized water to remove free inorganic ions, and then washed twice with absolute ethanol to remove water. The resulting precipitate was transferred to an oven at 90°C for drying after long-term suction filtration. The obtained dry powder is ground through a 200-mesh sieve, and calcined at 800° C. to obtain a Y ₂ O ₃ nanometer powder. Weigh 33.4778g of the Y ₂ O ₃ nanopowder, the addition amount of α-Al ₂ O ₃ , Nd ₂ O ₃ , CaO, Cr ₂ O ₃ and high-purity TEOS is the same as in Example 1, and the other processes are the same as in Example 1 same.

Example 10: Weigh 266.7634g of spectroscopically pure NH ₄ Al(SO ₄ ) ₂ ·12H ₂ O and 186.0965g of spectroscopically pure NH ₄ HCO ₃ , and prepare 0.25M NH ₄ Al(SO ₄ ) ₂ solution and 2.0 M NH ₄ HCO ₃ solution. Slowly add 0.25M NH ₄ Al(SO ₄ ) ₂ solution dropwise to 2.0M NH ₄ HCO ₃ solution while stirring at room temperature, the obtained white precipitate is aged for 12 hours and washed 3 times with deionized water to remove free inorganic ions, and then washed twice with absolute ethanol to remove water. The resulting precipitate was transferred to an oven at 90°C for drying after long-term suction filtration. The obtained dry powder is ground through a 200-mesh sieve, and calcined at 1000° C. to obtain an Al ₂ O ₃ nanometer powder. Weigh 25.4645g of the Al ₂ O ₃ nanopowder, the addition amount of commercial Y ₂ O ₃ , Nd ₂ O ₃ , CaO, Cr ₂ O ₃ and high-purity TEOS is the same as in Example 1, and the other processes are the same as in Example 2 .

Example 11: Prepare Y ₂ O ₃ nano powder according to Example 4, and prepare Al ₂ O ₃ nano powder according to Example 4. Weigh _33.4778g of the _Y2O3 nanopowder, _25.4645g of _{the Al2O3nanopowder} , and the addition amount of _commercial high-purity _Nd2O3 , CaO, _Cr2O3 and TEOS is the same as in Example 1, and the other Process is identical with embodiment 2.

Example 12: Weigh 113.5713g spectrally pure Y(NO ₃ ) ₃ ·6H ₂ O, and 140.6477g spectrally pure NH ₄ HCO ₃ , and configure them into 0.15M Y(NO ₃ ) ₃ solution and 2.0M _{NH4HCO3 solution} . Weigh 25.4645 g of α-Al ₂ O ₃ powder with a purity of 99.99% and disperse it into the NH ₄ HCO ₃ solution, and stir for 1 hour. Slowly add 0.15M Y(NO ₃ ) ₃ solution dropwise to the NH ₄ HCO ₃ solution dispersed with α-Al ₂ O ₃ powder while stirring at room temperature, and then treat the coated powder according to the steps in Example 4. According to the quality of the obtained Y ₂ O ₃ wrapped α-Al ₂ O ₃ composite powder, high-purity Nd ₂ O ₃ , CaO, Cr ₂ O ₃ and TEOS were added correspondingly, and other processes were the same as in Example 1.

Example 13: Weigh 226.4332g of spectroscopically pure NH ₄ Al(SO ₄ ) ₂ ·12H ₂ O and 315.9236g of spectroscopically pure NH ₄ HCO ₃ , and configure them into 0.25M NH ₄ Al(SO ₄ ) ₂ solution and 2.0 M in NH ₄ HCO ₃ solution. Weigh 33.4778g of Y ₂ O ₃ powder with a purity of 99.99% and disperse it into the NH ₄ HCO ₃ solution, and stir for 1 hour. Slowly add 0.25M NH ₄ Al(SO ₄ ) ₂ solution dropwise to the NH ₄ HCO ₃ solution dispersed with Y ₂ O ₃ powder while stirring at room temperature, and then treat the coated powder according to the steps in Example 5. According to the quality of the obtained Al ₂ O ₃ wrapped Y ₂ O ₃ composite powder, high-purity Nd ₂ O ₃ , CaO, Cr ₂ O ₃ and TEOS were added correspondingly, and other processes were the same as in Example 2.

Example 14: 281.3475g of spectroscopically pure Al(NO ₃ ) ₃ 9H ₂ O and 172.3680g of spectroscopically pure Y(NO ₃ ) ₃ .6H ₂ O were dissolved in deionized water. Al ³⁺ and Y ³⁺ Concentrations are 0.25M and 0.15M respectively, this mixed salt solution is slowly added dropwise in the ammonia solution containing surfactant (polyethylene glycol, PEG1000), the amount of surfactant is aluminum and yttrium inorganic salt solution weight 1 %, the pH value was adjusted to about 9 with ammonia water to obtain a white precipitate, and the treatment process of the precursor was the same as that of Example 5. And carry out calcining treatment at 1000 DEG C to obtain pure YAG phase nanopowder. According to the quality of the obtained YAG powder, high-purity Nd ₂ O ₃ , CaO, Cr ₂ O ₃ and TEOS were added correspondingly, and other processes were the same as in Example 1.

Example 15: 47.3940g spectrally pure Al(NO ₃ ) ₃ 9H ₂ O, 29.0360g spectrally pure Y(NO ₃ ) ₃ 6H ₂ O and 42.4060g citric acid were dissolved in deionized water and stirred to form a uniform The solution. The beaker containing the solution was placed on a magnetic stirrer, and the solution was evaporated with constant stirring at 80° C., finally forming a light yellow transparent jelly. Put the gel into a silicon carbide rod furnace at 200°C for heat treatment to form light yellow loose precursor powder. The precursor powder is calcined at 850°C to generate pure YAG phase powder. According to the quality of the obtained YAG powder, high-purity Nd ₂ O ₃ , CaO, Cr ₂ O ₃ and TEOS were added correspondingly, and other processes were the same as in Example 1.

Example 16: 25.4839g of α-Al ₂ O ₃ powder with a purity of 99.99%, 32.1638g of Y ₂ O ₃ powder with a purity of 99.99%, 2.9556g of Yb ₂ O ₃ powder with a purity of 99.95%, 0.007g CaO powder with a purity of 99.99%, 0.0095g of Cr ₂ O ₃ powder with a purity of 99.99% and 0.3031g of high-purity TEOS are put into a ball mill jar of polyconcave fluoride, and 180g of high-purity agate balls and 22ml of absolute ethanol are added, Then ball milled for 10 hours. After drying in an oven at 90°C, it was ground through a 100-mesh sieve. Use 100MPa pressure to press axially and unidirectionally, press it into a Φ20 disc, and then cold isostatic press under 300MPa pressure to further increase the density of the green body. Sintering is carried out in a vacuum sintering furnace, and the sample is placed in a molybdenum crucible. The heating mechanism of the furnace is: 30°C/min from room temperature to 1150°C, 10°C/min from 1150°C to 1770°C, and 10 hours holding time at 1770°C. From 1780°C to 1500°C, the temperature is lowered at 5°C/min, and below 1500°C, it is cooled with the furnace. Finally, the ceramics were ground and polished to a thickness of 1 mm with a surface grinder and diamond paste. The relative density of the ceramics obtained by sintering is >99.9%. After polishing, 0.025at% Cr ⁴⁺ , 5.0at% Yb ³⁺ : YAG ceramics are annealed. The holding time at 1450°C is 20 hours, then cool to 450°C at 1°C/min, and then cool with the furnace. The annealed ceramics were ground and polished to a thickness of 0.5 mm using a surface grinder and diamond paste. See Figure 4 for the physical photo of 0.025at%Cr ⁴⁺ , 5.0at%Yb ³⁺ :YAG ceramic 0.5mm piece after polishing, and Figure 5 for the morphology and structure of its fracture. The relative density of the ceramic is more than 99.9%, the linear transmittance at the laser wavelength (1064nm) is as high as 75%, and the average grain size is 40 microns.

Example 17: 25.4648g α-Al ₂ O ₃ powder with a purity of 99.99%, 32.1215g Y ₂ O ₃ powder with a purity of 99.99%, 2.9556g Yb ₂ O ₃ powder with a purity of 99.95%, 0.0280g purity 99.99% CaO powder, 0.0380g Cr ₂ O ₃ powder with a purity of 99.99%, and 0.303 1g high-purity TEOS. Other processes are the same as in Example 1. After polishing, a 0.075 at% Cr ⁴⁺ , 5.0 at% Yb ³⁺ :YAG transparent ceramic sheet with a thickness of 1 mm was obtained.

Claims (8)

1, the yttrium aluminum garnet transparent ceramic material of codope is characterized in that: for Cr ⁴⁺, Nd ³⁺: the YAG system, Cr ionic doping is 0.02～0.5at%, Nd ionic doping is 0.5～4.0at%.

2, by the yttrium aluminum garnet transparent ceramic material of the described codope of claim 1, it is characterized in that: for Cr ⁴⁺, Nd ³⁺: the YAG system, Cr ionic doping is 0.05～0.1at%, Nd ionic doping is 0.5～1.5at%.

3, by the yttrium aluminum garnet transparent ceramic material of claim 1 or 2 described codopes, it is characterized in that average grain size is 1-100 μ m.

4, a kind of method for preparing yttrium aluminum garnet transparent ceramic material as claimed in claim 1 or 2 comprises selection, ball milling mixing, drying, moulding, sintering and the annealing process step of raw material and sintering aid,

It is characterized in that concrete processing step is:

Step 1: carry out weighing by claim 1 or 2 described proportionings; The sintering aid that is made is Li ₂O, Na ₂O, K ₂O, CaO, MgO, SiO ₂Or in the tetraethoxy one or both, addition is 10 ²Ppm;

Step 2: the mixing in planetary ball mill with described powder of step 1 and sintering aid, working medium is dehydrated alcohol or deionized water;

Step 3:90-100 ℃ of oven dry slurry, grinding is sieved, and dry-pressing adds cold isostatic compaction;

Step 4: vacuum sintering:

1. the biscuit that dry-pressing is added cold isostatic compaction directly carries out vacuum sintering, and heat-up rate is 1～20 ℃/mim, and sintering temperature is 1650～1850 ℃, and soaking time is 5～40 hours, and vacuum tightness is 10 ^-2～10 ^-4Pa;

2. or the biscuit that dry-pressing is added cold isostatic compaction at vacuum oven sintering in two steps, the first step was 1000～1500 ℃ of pre-burnings 2～20 hours, heat-up rate is 1～20 ℃/mim, vacuum tightness is 10 ^-2～10 ⁴Pa; Second step, heat-up rate was 1～20 ℃/mim 1700～1850 ℃ of insulations 5～40 hours, and vacuum tightness is 10 ^-2～10 ^-4Pa;

3. or the biscuit that dry-pressing is added cold isostatic compaction in the Si-Mo rod stove of oxidizing atmosphere, do not have pressure presintering: heat-up rate is 1～20 ℃/mim, and sintering temperature is 800～1200 ℃, and the pre-burning time is 2～20 hours; Place the base substrate after the presintering vacuum sintering furnace to carry out double sintering, sintering temperature is 1650～1850 ℃, and soaking time is 5～40 hours, and vacuum tightness is 10 ^-2～10 ^-4Pa;

Step 5: with the Cr of vacuum sintering, the Nd:YAG pottery carries out anneal in the Si-Mo rod stove of oxidizing atmosphere: annealing temperature is 800～1600 ℃, and annealing time is 2～40 hours.

5, by the yttrium aluminum garnet transparent ceramic preparation methods of the described codope of claim 4, the selection that it is characterized in that raw material be in following (a)～(k) any one:

(a) Shang Yong high-purity α-Al ₂O ₃, Y ₂O ₃, Cr ₂O ₃And Nd ₂O ₃Powder;

(b) Shang Yong high-purity γ-Al ₂O ₃, Y ₂O ₃, Cr ₂O ₃And Nd ₂O ₃Powder;

(c) Shang Yong high-purity α-Al ₂O ₃, γ-Al ₂O ₃, Y ₂O ₃, Cr ₂O ₃And Nd ₂O ₃Powder;

(d) Shang Yong high-purity α-Al ₂O ₃, Cr ₂O ₃, Nd ₂O ₃High-purity Y with the wet chemistry method preparation ₂O ₃Nano-powder;

(e) Shang Yong high-purity γ-Al ₂O ₃, Cr ₂O ₃, Nd ₂O ₃High-purity Y with the wet chemistry method preparation ₂O ₃Nano-powder;

(f) Shang Yong high-purity Y ₂O ₃, Cr ₂O ₃, Nd ₂O ₃High-purity Al with the wet chemistry method preparation ₂O ₃Nano-powder;

(g) high-purity Al of wet chemistry method preparation ₂O ₃, Y ₂O ₃Nano-powder and commercial high-purity Cr ₂O ₃, Nd ₂O ₃Powder;

(h) Y of heterogeneous precipitation method preparation ₂O ₃Parcel Al ₂O ₃Powder and commercial high-purity Cr ₂O ₃, Nd ₂O ₃Powder;

(i) Al of heterogeneous precipitation method preparation ₂O ₃Parcel Y ₂O ₃Powder and commercial high-purity Cr ₂O ₃, Nd ₂O ₃Powder;

(j) high-purity YAG nano-powder and commercial high-purity Cr of wet chemistry method preparation ₂O ₃, Nd ₂O ₃Powder;

(k) high-purity N d:YAG nano-powder and commercial high-purity Cr of wet chemistry method preparation ₂O ₃Powder;

Above-described commercialization powder purity high-purity or the wet chemistry method preparation is 99.95-99.99%.

6, by the yttrium aluminum garnet transparent ceramic preparation methods of the described codope of claim 5, it is characterized in that: described wet chemistry method is a kind of in the precipitator method or the sol-gel method.

7, by the yttrium aluminum garnet transparent ceramic preparation methods of the described codope of claim 4, it is characterized in that described planetary ball mill rotating speed is 100-400rpm, the ball milling time is 2-20 hour.

8, by the yttrium aluminum garnet transparent ceramic preparation methods of the described codope of claim 4, it is characterized in that described moulding is:

(a) the axial unidirectional pressuring method that adopts in the dry-pressing formed process, pressure is 50～100MPa, 0.5～3 minute dwell time;

(b) biscuit after dry-pressing formed after vacuum packaging, cold isostatic compaction under the pressure of 200～400MPa, 1～5 minute dwell time, making biscuit density is 45～65% of component theoretical density.

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