High-thermal-conductivity and high-luminous-efficiency composite fluorescent ceramic for laser illumination, and preparation method therefor

Abstract

A high-thermal-conductivity and high-luminous-efficiency composite fluorescent ceramic for laser illumination, and a preparation method therefor. The composite fluorescent ceramic is composed of bowl-shaped fluorescent ceramic and Al2O3 ceramic coating the periphery of the bowl-shaped fluorescent ceramic, wherein the composition of the bowl-shaped fluorescent ceramic is (RE1 - xCex)3Al5O12, Re is one or more of Y, Lu, Gd and Tb, and 0.0005≤x≤0.005; and the parameters of the bowl-shaped fluorescent ceramic are: a curvature of 0.2-0.8, a bottom diameter of 5-30 mm, and a height of 0.5-3 mm. A fluorescent ceramic biscuit is firstly prepared by using a gel casting method, the periphery of the fluorescent ceramic biscuit is then coated with an Al2O3 ceramic powder, and the fluorescent ceramic biscuit is subjected to dry pressing molding, vacuum sintering, air annealing and surface polishing treatment to obtain a composite fluorescent ceramic. The prepared composite ceramic achieves high-brightness white light emission under excitation of a blue light LD chip with a wavelength of 455 nm, and has a bearable excitation power density of 45-55 W / mm2, a luminous efficiency of 200-260 lm / W and a thermal conductivity of 20-26 Wm-1k-1.

Description

A high thermal conductivity and high light efficiency composite fluorescent ceramic for laser lighting and its preparation method Technical Field

[0001] The present invention relates to the technical field of fluorescent ceramics, and in particular to a high-thermal-conductivity and high-light-efficiency composite fluorescent ceramic for laser lighting and a preparation method thereof. Background Art

[0002] Fluorescent ceramics are a kind of light-to-light conversion functional material with high conversion efficiency, high temperature resistance, excellent thermal shock resistance and long service life under the excitation of high-power blue light diode light source. They are widely used in technical fields such as high-power lighting and high-lumen display. The light source equipment that uses laser as the excitation source to excite fluorescent ceramics has many advantages such as high brightness, long range, long life and small size. However, fluorescent ceramics are not suitable for high-power laser (>10W / mm 2 ) under the excitation of the laser, the laser irradiation area of ​​the fluorescent ceramic will gather a lot of heat (the main source is the energy loss in the light conversion process). Since the thermal conductivity of the fluorescent ceramic is about 14Wm ‑1 K ‑1 , insufficient to dissipate heat quickly, causing the ceramic temperature at the laser spot to rise sharply, resulting in reduced luminous intensity and luminous saturation. Furthermore, because the refractive index of fluorescent ceramics is relatively high (for example, YAG has a refractive index of n=1.84), some light is limited by total internal reflection within the material (the refractive index of air is n=1.0), or leaks from the sides or edges of the emitter, reducing overall luminous efficiency. Furthermore, because lasers are point sources, incident blue light that has not been scattered or converted can pass directly through the fluorescent material, causing a "yellow ring effect" and compromising lighting quality.

[0003] In order to achieve higher luminous efficiency and luminous quality, researchers have designed the microstructure of YAG:Ce fluorescent ceramics. The literature (High-performance Al2O3‒YAG: Ce composite ceramic phosphors for miniaturization of high-brightness white light-emitting diodes. Ceramics International,46(1), 653-662.) reported that the introduction of the second phase Al2O3 into YAG:Ce ceramics can act as a scattering center to change the propagation path of the excitation light in the ceramic and can also act as a high thermal conductivity second phase to improve the thermal conductivity, ultimately achieving a front light flux of 639lm and a luminous flux of 18.2W / m -1 K -1The thermal conductivity of the ceramic is improved, but some light still leaks out from the sides, making it difficult to further improve the efficiency. German company OSRAM studied the effect of porosity on luminescence performance. By controlling the scattering and absorption coefficients within the fluorescent ceramic, the thickness, and the optical path length at all angles through the converter, the blue / yellow ratio of the luminescence can be adjusted. The results show that appropriate pores can control the propagation path of blue light and achieve optimal luminous efficiency. High porosity can also greatly improve the uniformity of luminescence at different angles. However, pores can affect the thermal stability of the fluorescent ceramic to a certain extent.

[0004] To address the low thermal conductivity of fluorescent ceramics used in laser lighting, a second phase can be introduced to improve the overall thermal conductivity of the ceramic. However, in composite ceramics, this highly thermally conductive second phase exists as a diffuse phase within the matrix, significantly reducing its heat dissipation capacity. Furthermore, increasing the second phase content increases internal scattering within the ceramic, further strengthening the internal scattering within the composite ceramic, causing more light to leak out the sides and reducing luminous efficiency. Finally, the "yellow ring effect" in laser lighting can affect lighting quality. While improvements can be made through the addition of a second phase, pores, surface roughening, and surface modification, these methods, while improving luminous quality and efficiency, inevitably increase heat generation, which can affect thermal stability to a certain extent. Summary of the Invention

[0005] One of the purposes of the present invention is to provide a high thermal conductivity and high light efficiency composite fluorescent ceramic for laser lighting, which has the advantages of high thermal conductivity and high light efficiency as a luminescent material.

[0006] One of the purposes of the present invention is to provide a method for preparing a high thermal conductivity and high light efficiency composite fluorescent ceramic for laser lighting, which is easy to realize industrial production.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] In the first aspect, the present invention provides a high thermal conductivity and high light efficiency composite fluorescent ceramic for laser lighting, wherein the composite fluorescent ceramic is composed of a bowl-shaped fluorescent ceramic and an Al2O3 ceramic coated around the bowl-shaped fluorescent ceramic. The composition of the bowl-shaped fluorescent ceramic is (Re 1-x Ce x )3Al5O 12 , Re is one or more of Y, Lu, Gd, Tb, 0.0005≤x≤0.005, and the parameters of the bowl-shaped fluorescent ceramic are: curvature 0.2~0.8, bottom diameter 5~30mm, and height 0.5~3mm.

[0009] The composite fluorescent ceramic can achieve high-brightness white light emission under the excitation of a blue light LD chip with a wavelength of 455nm and can withstand an excitation power density of 45W / mm 2~55W / mm 2 , luminous efficiency 200 ~ 260lm / W. Its thermal conductivity at room temperature is 25 ~ 30Wm -1 k -1 .

[0010] In a second aspect, the present invention further provides a method for preparing the above-mentioned high thermal conductivity and high light efficiency composite fluorescent ceramic for laser lighting, which specifically comprises the following steps:

[0011] Step 1: Prepare fluorescent ceramic blank by gel casting method:

[0012] (1.1) Preparation of raw material powder: According to the composition (Re 1-x Ce x )3Al5O 12 , weighing raw material powders in a stoichiometric ratio of 0.0005≤x≤0.005, wherein Re is one or more of Y, Lu, Gd, and Tb; adding dispersant PEI, sintering aids MgO and TEOS, ball milling media anhydrous ethanol and Al2O3 grinding balls, and obtaining a mixed slurry after ball milling; drying the slurry, sieving it, and then calcining it in a muffle furnace to obtain a fluorescent ceramic powder;

[0013] (1.2) Preparation of injection molding slurry: Add dispersant ammonium citrate, pH regulator tetramethylammonium hydroxide, monomer acrylamide, crosslinking agent N-N' methylene bisacrylamide, pure water and Al2O3 grinding balls to the fluorescent ceramic powder prepared in step (1). After ball milling, filter out the slurry, vacuum degas, add catalyst tetramethylethylenediamine, and mix well.

[0014] (1.3) Gel casting: Pour the mixed slurry into a bowl-shaped mold and heat it at 50-80°C to solidify it into shape;

[0015] (1.4) Drying and debinding: The solidified green body is dried in a constant temperature and humidity chamber for 12 to 36 hours. After drying, it is placed in a muffle furnace for debinding to obtain a fluorescent ceramic green body;

[0016] Step 2: Preparation of composite fluorescent ceramics:

[0017] (2.1) Wrapping Al2O3 ceramic powder around the fluorescent ceramic green body prepared in step 1 and dry pressing to obtain a composite ceramic green body disc;

[0018] (2.2) The composite ceramic green body disc is placed in a vacuum sintering furnace for sintering to obtain a composite fluorescent ceramic, which is then air annealed in a muffle furnace and the ceramic surface is polished to obtain the composite fluorescent ceramic.

[0019] Preferably, in step (1.1), the amount of dispersant added is 0.1-0.5wt.% of the total mass of the raw material powder; the amount of MgO added is 0.1-0.6wt.% of the total mass of the raw material powder; the amount of TEOS added is 0.3-0.5wt.% of the total mass of the raw material powder; the ball mill speed is 160-220r / min, and the ball milling time is 12-24h; the drying temperature is 50-80°C, and the time is 6-24h; the sieve mesh size is 80-300 mesh; and the muffle furnace calcination temperature is 800-1000°C.

[0020] Preferably, in step (1.2), the amount of dispersant added is 0.25-0.5wt.% of the fluorescent ceramic powder, the amount of pH adjuster added is 1-1.5wt.% of the fluorescent ceramic powder, the amount of monomer added is 2-3wt.% of the fluorescent ceramic powder, the amount of cross-linker added is 0.2-0.3wt.% of the fluorescent ceramic powder, and the amount of catalyst added is 0.2-0.5wt.% of the fluorescent ceramic powder; the ball mill speed is 140-200r / min, and the ball milling time is 8-12h; the slurry solid content is 40-60vol.%.

[0021] Preferably, in step (1.4), the drying temperature is 25-60° C., the drying humidity is 30%-80%, the debinding temperature is 600-900° C., and the debinding time is 24-72 hours.

[0022] Preferably, in step (2.1), the tableting pressure is 20 to 200 MPa, and the holding time is 10 to 30 minutes.

[0023] Preferably, in step (2.2), the vacuum sintering temperature is 1750-1800° C., and the holding time is 8-30 hours.

[0024] Preferably, the air annealing temperature in step (2.2) is 1400-1450° C., and the annealing time is 8-16 hours.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The composite ceramic prepared by the present invention can achieve high-brightness white light emission under the excitation of a blue light LD chip with a wavelength of 455nm and can withstand an excitation power density of 45W / mm 2 ~55W / mm 2 , luminous efficiency 200~260lm / W, its thermal conductivity is 20~26Wm -1 k -1 .

[0027] (2) The fluorescent ceramic of the present invention is designed into a bowl shape. By flexibly adjusting the bottom radius and height of the bowl-shaped ceramic, the light extraction rate can be effectively improved, achieving high lumen efficiency and high brightness luminous performance. At the same time, the transparent Al2O3 is used as the backplane for reflective packaging, making the ratio of blue light and yellow light more uniform, thereby improving the lighting effect.

[0028] (3) The present invention adopts gel injection molding to prepare bowl-shaped fluorescent ceramic blanks, which can effectively control the fine structure of the blanks without defects such as cracks and deformation, and at the same time achieve mass production, which is conducive to the industrialization of the preparation of the composite fluorescent ceramics.

[0029] (4) The present invention adopts a co-firing scheme to tightly bond the bowl-shaped fluorescent ceramic and the Al2O3 ceramic together, and the continuous phase of the Al2O3 substrate with high thermal conductivity provides better heat dissipation, thereby improving the overall thermal conductivity of the composite ceramic, so that it can be used in high-power lighting devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG1 is a schematic diagram of the structure of the composite fluorescent ceramic of the present invention; in the figure: 1-bowl-shaped fluorescent ceramic; 2-Al2O3 ceramic.

[0031] FIG2 is a schematic diagram of the optical path of the composite fluorescent ceramic reflective lighting in the present invention.

[0032] FIG3 is a graph showing the thermal conductivity of the composite fluorescent ceramics prepared in Examples 1-3 of the present invention.

[0033] FIG4 is a graph showing the luminous efficiency of the composite fluorescent ceramics prepared in Examples 1-3 of the present invention. Implementation Method

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

[0035] The raw material powders used in the following examples are all commercially available products with a purity greater than 99.9%. Example

[0036] The prepared composite fluorescent ceramic is shown in FIG1 , which consists of a bowl-shaped fluorescent ceramic 1 (0.05 at.% Ce:YAG) and an Al2O3 ceramic 2. The parameters of the bowl-shaped fluorescent ceramic 1 are: curvature 0.2, bottom diameter 10 mm, and height 1 mm.

[0037] Step 1: Prepare Ce:YAG ceramic green body by gel casting method:

[0038] (1) Preparation of raw material powder: According to the composition (Y 0.9995 Ce 0.0005 )3Al5O 12The raw material powders were weighed in a stoichiometric ratio, 0.1 wt.% of PEI, 0.1 wt.% of MgO, and 0.3 wt.% of TEOS, anhydrous ethanol, and Al2O3 grinding balls were added, and the mixture was ball-milled at 160 rpm for 12 h to obtain a mixed slurry; the mixture was dried at 50°C for 6 h, sieved through an 80-mesh sieve, placed in a muffle furnace, and calcined at 800°C to obtain Ce:YAG ceramic powder;

[0039] (2) Preparation of injection molding slurry: 0.25 wt.% of ammonium citrate, 1 wt.% of tetramethylammonium hydroxide, 2 wt.% of acrylamide, 0.2 wt.% of N-N'methylenebisacrylamide, pure water and Al2O3 grinding balls were added to the Ce:YAG ceramic powder prepared in step (1). After ball milling at 140 r / min for 8 h, the slurry was filtered out. The solid content of the slurry was 40 vol.%. After vacuum degassing, 110 μL of tetramethylethylenediamine was added and mixed evenly.

[0040] (3) Gel casting: Pour the mixed slurry into a customized bowl-shaped mold and heat-initiate at 50°C to solidify the mixture;

[0041] (4) Drying and debinding: The solidified green body was dried in a constant temperature and humidity chamber at 25°C and 30% humidity for 12 h. After drying, it was placed in a muffle furnace for debinding at a debinding temperature of 600°C and a debinding time of 24 h to obtain a Ce:YAG ceramic green body.

[0042] Step 2: Preparation of composite fluorescent ceramics:

[0043] (5) Wrap Al2O3 ceramic powder around the Ce:YAG ceramic green body and press it into shape using a dry press with a pressing pressure of 20 MPa and a holding time of 10 min to obtain a composite ceramic green body disc;

[0044] (6) The composite ceramic green body disc was placed in a vacuum sintering furnace and sintered at a vacuum sintering temperature of 1750°C for 8 hours to obtain a composite fluorescent ceramic. The composite fluorescent ceramic was then air annealed in a muffle furnace at a temperature of 1400°C for 8 hours. After the ceramic surface was polished, a fluorescent ceramic device based on a composite of Ce:YAG fluorescent ceramic and Al2O3 ceramic was obtained.

[0045] Using blue laser to excite composite fluorescent ceramics, when the blue light output power is 5W, its power density reaches 47.6W / mm -2 The fluorescent ceramic device emits stable light, has an operating temperature of 90°C, a luminous efficiency of 220lm / W, a luminous flux of up to 1100lm, and a thermal conductivity of 25.2Wm -1 k -1 , as shown in Figure 3 and Figure 4. Example

[0046] The prepared composite fluorescent ceramic is shown in FIG1 , which consists of a bowl-shaped fluorescent ceramic 1 (0.1 at.% Ce:YAG) and an Al2O3 ceramic 2. The parameters of the bowl-shaped fluorescent ceramic 2 are: curvature 0.5, bottom diameter 15 mm, and height 2 mm.

[0047] Step 1: Prepare Ce:YAG ceramic green body by gel casting method:

[0048] (1) Preparation of raw material powder: According to the composition (Y 0.999 Ce 0.001 )3Al5O 12 The raw material powders were weighed in a stoichiometric ratio, 0.5 wt.% of PEI, 0.6 wt.% of MgO, and 0.5 wt.% of TEOS, anhydrous ethanol, and Al2O3 grinding balls were added, and the mixture was ball-milled at 220 rpm for 24 h to obtain a mixed slurry; the mixture was dried at 80°C for 24 h, sieved through a 300-mesh sieve, placed in a muffle furnace, and calcined at 1000°C to obtain Ce:YAG ceramic powder;

[0049] (2) Preparation of injection molding slurry: 0.5 wt.% of ammonium citrate, 1.5 wt.% of tetramethylammonium hydroxide, 3 wt.% of acrylamide, 0.3 wt.% of N-N'methylenebisacrylamide, pure water and Al2O3 grinding balls were added to the Ce:YAG ceramic powder prepared in step (1). After ball milling at 200 r / min for 12 h, the slurry was filtered out. The solid content of the slurry was 60 vol.%. After vacuum degassing, 200 μL of tetramethylethylenediamine was added and mixed evenly.

[0050] (3) Gel casting: The mixed slurry is poured into a customized bowl-shaped mold and thermally initiated at 80°C to solidify the mold;

[0051] (4) Drying and debinding: The solidified green body was dried in a constant temperature and humidity chamber at 60°C and 80% humidity for 36 h. After drying, it was placed in a muffle furnace for debinding at a debinding temperature of 900°C and a debinding time of 72 h to obtain a Ce:YAG ceramic green body.

[0052] Step 2: Preparation of composite fluorescent ceramics:

[0053] (5) Wrap Al2O3 ceramic powder around the Ce:YAG ceramic green body and press it into shape using a dry press with a pressing pressure of 200 MPa and a holding time of 30 min to obtain a composite ceramic green body disc;

[0054] (6) The composite ceramic green body disc was placed in a vacuum sintering furnace and sintered at a vacuum sintering temperature of 1800°C and a holding time of 30 hours to obtain a composite fluorescent ceramic. The composite fluorescent ceramic was then air annealed in a muffle furnace at a temperature of 1450°C and an annealing time of 15 hours. After the ceramic surface was polished, a fluorescent ceramic device based on a composite of Ce:YAG fluorescent ceramic and Al2O3 ceramic was obtained.

[0055] Using blue laser to excite composite fluorescent ceramics, when the blue light output power is 5W, its power density reaches 47.6W / mm -2 The fluorescent ceramic device has stable luminescence, an operating temperature of 95°C, a luminous efficiency of 240lm / W, a luminous flux of up to 1200lm, and a thermal conductivity of 26.6Wm -1 k -1 , as shown in Figure 3 and Figure 4. Example

[0056] The prepared composite fluorescent ceramic is shown in Figure 1, which consists of bowl-shaped fluorescent ceramic 1 (0.05at.%Ce:LuAG) and Al2O3 ceramic 2. The parameters of the bowl-shaped fluorescent ceramic 1 are: curvature 0.8, bottom diameter 25mm, and height 2mm.

[0057] Step 1: Prepare Ce:LuAG ceramic green body by gel casting method:

[0058] (1) Preparation of raw material powder: According to the composition (Lu 0.9995 Ce 0.0005 )3Al5O 12 The raw material powders were weighed in a stoichiometric ratio, 0.3 wt.% of PEI, 0.4 wt.% of MgO, and 0.4 wt.% of TEOS, anhydrous ethanol, and Al2O3 grinding balls were added, and the mixture was ball-milled at 210 rpm for 20 h to obtain a mixed slurry; the mixture was dried at 70°C for 18 h, sieved through a 200-mesh sieve, placed in a muffle furnace, and calcined at 900°C to obtain Ce:LuAG ceramic powder;

[0059] (2) Preparation of injection molding slurry: 0.4 wt.% of ammonium citrate, 1.3 wt.% of tetramethylammonium hydroxide, 2.5 wt.% of acrylamide, 0.25 wt.% of N-N'methylenebisacrylamide, pure water and Al2O3 grinding balls were added to the Ce:LuAG ceramic powder prepared in step (1). After ball milling at 180 r / min for 10 h, the slurry was filtered out. The solid content of the slurry was 50 vol.%. After vacuum degassing, 170 μL of tetramethylethylenediamine was added and mixed evenly.

[0060] (3) Gel casting: The mixed slurry is poured into a customized bowl-shaped mold and thermally initiated at 70°C to solidify the mold;

[0061] (4) Drying and debinding: The solidified green body was dried in a constant temperature and humidity chamber at 50°C and 50% humidity for 12 h. After drying, it was placed in a muffle furnace for debinding at a debinding temperature of 750°C and a debinding time of 48 h to obtain a Ce:LuAG ceramic green body.

[0062] Step 2: Preparation of composite fluorescent ceramics:

[0063] (5) Wrap Al2O3 ceramic powder around the Ce:LuAG ceramic green body and press it into shape using a dry press with a pressing pressure of 50 MPa and a holding time of 20 min to obtain a composite ceramic green body disc;

[0064] (6) The composite ceramic green body disc was placed in a vacuum sintering furnace and sintered at a vacuum sintering temperature of 1800°C and a holding time of 8 hours to obtain a composite fluorescent ceramic. The composite fluorescent ceramic was then air annealed in a muffle furnace at a temperature of 1400°C and an annealing time of 8 hours. After the ceramic surface was polished, a fluorescent ceramic device based on a composite of Ce:LuAG fluorescent ceramic and Al2O3 ceramic was obtained.

[0065] Using blue laser to excite composite fluorescent ceramics, when the blue light output power is 5W, its power density reaches 47.6W / mm -2 The fluorescent ceramic device has stable luminescence, an operating temperature of 75°C, a luminous efficiency of 265lm / W, a luminous flux of up to 1325lm, and a thermal conductivity of 23.2Wm -1 k -1 , as shown in Figure 3 and Figure 4.

[0066] FIG2 is a schematic diagram of the reflective lighting light path of the composite fluorescent ceramic of the present invention; Al2O3 is used as a backplane for reflective packaging, so that the ratio of blue and yellow light in the reflected light is more uniform, thereby improving the white light lighting effect.

[0067] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A high thermal conductivity and high light efficiency composite fluorescent ceramic for laser lighting, characterized in that: The composite fluorescent ceramic is composed of a bowl-shaped fluorescent ceramic and an Al2O3 ceramic coated around the bowl-shaped fluorescent ceramic. The composition of the bowl-shaped fluorescent ceramic is (Re 1-x Ce x )3Al5O 12 , Re is one or more of Y, Lu, Gd, Tb, 0.0005≤x≤0.005, and the parameters of the bowl-shaped fluorescent ceramic are: curvature 0.2~0.8, bottom diameter 5~30mm, and height 0.5~3mm.

2. A method for preparing the high thermal conductivity and high light efficiency composite fluorescent ceramic for laser lighting according to claim 1, characterized in that: The specific steps include: Step 1: Prepare fluorescent ceramic blank by gel casting method: (1.1) Raw material powder preparation: according to the composition (Re 1-x Ce x )3Al5O 12 , weighing raw material powders in a stoichiometric ratio of 0.0005≤x≤0.005, wherein Re is one or more of Y, Lu, Gd, and Tb; adding dispersant PEI, sintering aids MgO and TEOS, ball milling media anhydrous ethanol and Al2O3 grinding balls, and obtaining a mixed slurry after ball milling; drying the slurry, sieving it, and calcining it in a muffle furnace to obtain fluorescent ceramic powder; (1.2) Preparation of injection molding slurry: add dispersant ammonium citrate, pH adjuster tetramethylammonium hydroxide, monomer acrylamide, crosslinking agent N-N'methylenebisacrylamide, pure water and Al2O3 grinding balls to the fluorescent ceramic powder prepared in step (1), filter out the slurry after ball milling, add catalyst tetramethylethylenediamine after vacuum degassing, and mix well; (1.3) Gel casting: Pour the mixed slurry into a bowl-shaped mold, heat it at 50-80°C, and solidify it into shape; (1.4) Drying and debinding: The solidified body is dried in a constant temperature and humidity chamber for 12 to 36 hours, and then placed in a muffle furnace for debinding to obtain a fluorescent ceramic body; Step 2: Preparation of composite fluorescent ceramics: (2.1) Wrapping Al2O3 ceramic powder around the fluorescent ceramic green body obtained in step 1, dry pressing and forming, to obtain a composite ceramic green body disc; (2.2) The composite ceramic green body disc is placed in a vacuum sintering furnace for sintering to obtain a composite fluorescent ceramic, and air annealing is performed in a muffle furnace. The ceramic surface is polished to obtain a composite fluorescent ceramic.

3. The method for preparing the high thermal conductivity and high light efficiency composite fluorescent ceramic for laser lighting according to claim 2, characterized in that: In step (1.1), the amount of dispersant added is 0.1-0.5wt.% of the total mass of the raw material powder; the amount of MgO added is 0.1-0.6wt.% of the total mass of the raw material powder; the amount of TEOS added is 0.3-0.5wt.% of the total mass of the raw material powder; the ball mill speed is 160-220r / min, and the ball milling time is 12-24h; the drying temperature is 50-80℃, and the time is 6-24h; the sieve mesh number is 80-300 mesh; and the muffle furnace calcination temperature is 800-1000℃.

4. The method for preparing the high thermal conductivity and high light efficiency composite fluorescent ceramic for laser lighting according to claim 2, characterized in that: In step (1.2), the amount of dispersant added is 0.25-0.5wt.% of the fluorescent ceramic powder, the amount of pH adjuster added is 1-1.5wt.% of the fluorescent ceramic powder, the amount of monomer added is 2-3wt.% of the fluorescent ceramic powder, the amount of cross-linking agent added is 0.2-0.3wt.% of the fluorescent ceramic powder, and the amount of catalyst added is 0.2-0.5wt.% of the fluorescent ceramic powder; the ball mill speed is 140-200r / min, and the ball milling time is 8-12h; the slurry solid content is 40-60vol.%.

5. The method for preparing the high thermal conductivity and high light efficiency composite fluorescent ceramic for laser lighting according to claim 2, characterized in that: In step (1.4), the drying temperature is 25-60°C, the drying humidity is 30%-80%, the debinding temperature is 600-900°C, and the debinding time is 24-72h.

6. The method for preparing the high thermal conductivity and high light efficiency composite fluorescent ceramic for laser lighting according to claim 2, characterized in that: In step (2.1), the dry pressing pressure is 20 to 200 MPa, and the holding time is 10 to 30 minutes.

7. The method for preparing the high thermal conductivity and high light efficiency composite fluorescent ceramic for laser lighting according to claim 2, characterized in that: In step (2.2), the vacuum sintering temperature is 1750-1800° C., and the holding time is 8-30 hours.

8. The method for preparing the high thermal conductivity and high light efficiency composite fluorescent ceramic for laser lighting according to claim 2, characterized in that: In step (2.2), the air annealing temperature is 1400-1450° C., and the annealing time is 8-16 hours.

Images