A high thermal conductivity, high color rendering index composite fluorescent ceramic for laser lighting and its preparation method

Abstract

The present invention discloses a high thermal conductivity and high color rendering index composite fluorescent ceramic for laser lighting and a preparation method thereof, wherein the composite fluorescent ceramic comprises (Gd, Ce)3(Al, Ga)5O as a main phase. 12 phase, and the second phase Al2O3 uniformly distributed in the main phase, in which the luminescent ion is Ce 3+ ; Using GdGaO3, CeO2, and Al2O3 as the initial raw materials, the solid phase reaction method is adopted for sintering. The excitation spectrum of the composite ceramic prepared by the present invention is excited at a wavelength of 460nm, the main peak of the emission spectrum is between 567 and 582nm, and the half-maximum width is between 105 and 120nm. Under the excitation of a blue light LD (1 to 5W) with a wavelength of 455nm, warm white light emission is achieved, the color temperature is 3800 to 4250K, and the color rendering index is between 78 and 84; the thermal conductivity is 20 to 25Wm ‑1 k ‑1 Compared with single-phase fluorescent ceramics, the thermal conductivity is increased by 40-69%, and the preparation method is simple, green and environmentally friendly, and can be used for the industrial production of LD devices.

Description

Technical Field

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

[0002] Fluorescent ceramics are a type of light-to-light conversion material widely used in high-power lighting and high-lumen display technologies. Lasers used as excitation sources to excite fluorescent ceramics have many advantages, such as high brightness, long range, long life, and small size. They can be widely used in outdoor square lighting, sports venues, car headlights, and aviation and marine lighting. However, fluorescent ceramics are not suitable for high-power lasers (>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 , which is insufficient to dissipate heat quickly, causing the ceramic temperature at the laser point to rise sharply, resulting in a decrease in luminescence intensity and luminescence saturation. Furthermore, the emission spectrum of garnet-based fluorescent ceramics primarily covers yellow-green light, lacking sufficient red light components, resulting in poor color rendering performance (CRI ~ 60) and a high color temperature (> 6000K).

[0003] At present, a large number of literatures have studied the fluorescent ceramics of garnet system in order to realize the luminescence control of fluorescent ceramics. The literature ((Ce, Gd): YAG-Al2O3 composite ceramics for high-brightness yellow light-emitting diode applications. Journal of the European Ceramic Society, 2022 (3), 42, 1121-1131) reported that by doping Gd 3+ Can make Ce 3+The emission peak of the ion produces a red shift, which significantly improves the color rendering index, but the thermal stability is extremely poor. Therefore, the thermal conductivity of fluorescent ceramics is improved by introducing Al2O3 as the second phase, but the density of the prepared ceramics is not high, mainly because when the Gd doping amount is too high, (Ce, Gd): YAG decomposes at high temperature, resulting in no significant improvement in thermal conductivity. The literature (Effects of Ga substitution for Al on the fabrication and optical properties of transparent Ce: GAGG based ceramics Journal of the European Ceramic Society, 2017 (37), 13, 4109-4114) reported the use of Ga 3+ Replace Al 3+ The GAGG lattice is more stable and not easy to decompose at high temperature, but its thermal conductivity is very poor. If the thermal conductivity is improved by introducing Al2O3 as the second phase, it is easy to cause Ga 3+ (When Ga2O3 is used as raw material) it cannot replace the Al that enters the garnet 3+ CN111995398A discloses that doping red light ions can improve the color rendering index of fluorescent ceramics and achieve red light supplementation, but it reduces the thermal conductivity of the ceramics, greatly limiting the application of fluorescent ceramics under high-power laser illumination. Summary of the Invention

[0004] One of the purposes of the present invention is to provide a high thermal conductivity, high color rendering index composite fluorescent ceramic for laser lighting, which has the advantages of high thermal conductivity and high color rendering index as a luminescent material.

[0005] One of the purposes of the present invention is to provide a method for preparing high thermal conductivity and high color rendering index composite fluorescent ceramics for laser lighting, which is simple to operate and easy to realize industrial production.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] In the first aspect, the present invention provides a high thermal conductivity and high color rendering index composite fluorescent ceramic for laser lighting, wherein the composite fluorescent ceramic comprises (Gd, Ce)3(Al, Ga)5O as the main phase. 12 phase, and the second phase Al2O3 uniformly distributed in the main phase, in which the luminescent ion is Ce 3+ .

[0008] The composite fluorescent ceramic emits a main peak of 567-582 nm and a half-width of 105-120 nm under 460 nm wavelength excitation. When excited by a 1-5 W blue light LD with a wavelength of 455 nm, it emits warm white light with a color temperature of 3800-4250 K and a color rendering index of 78-84. The thermal conductivity of the composite fluorescent ceramic is 20-25 W / m -1 k -1 .

[0009] In a second aspect, the present invention also provides a method for preparing the high thermal conductivity and high color rendering index composite fluorescent ceramic for laser lighting, which adopts a solid phase reaction sintering method and specifically comprises the following steps:

[0010] (1) According to the chemical formula (Gd 1-x Ce x )3(Al 2+3x Ga 3-3x )O 12 The stoichiometric ratios of the elements in the mixture are respectively GdGaO3, CeO2, and Al2O3 as the initial raw materials, where x is Ce 3+ The molar percentage of the doped Gd site is 0.005≤x≤0.02; and 20% to 60% of the total mass of the raw material powder is weighed as the second phase of the ceramic;

[0011] (2) blending the weighed raw material powder and dispersant polyetherimide, adding anhydrous ethanol, and ball milling the mixture. The obtained mixed slurry is dried and sieved, and then the mixed powder is placed in a muffle furnace for calcination;

[0012] (3) placing the calcined powder into a mold for dry pressing, and then performing cold isostatic pressing to obtain a green body with a relative density of 50% to 55%;

[0013] (4) The green body is sintered at a high temperature, cooled to room temperature, and then double-sided polished to obtain the composite fluorescent ceramic.

[0014] Preferably, in step (2), the amount of the dispersant polyetherimide added is 0.8-1 wt.% of the total mass of the raw material powder, and the mass ratio of the total mass of the raw material powder to anhydrous ethanol is 1:1.5-3.

[0015] Preferably, the ball milling speed in step (2) is 180-250 rpm, and the ball milling time is 15-30 h.

[0016] Preferably, the drying temperature in step (2) is 50-80° C., and the drying time is 8-12 hours.

[0017] Preferably, the calcination temperature in step (2) is to increase the temperature to 600-800° C. at a heating rate of 2-10° C. / min at room temperature and keep the temperature for 5-7 hours.

[0018] Preferably, the cold isostatic pressing holding pressure in step (3) is 150 to 200 MPa, and the holding time is 200 to 400 s.

[0019] Preferably, the high-temperature sintering in step (3) is divided into two stages: pressureless pre-sintering and hot isostatic pressing sintering. Pressureless pre-sintering: sintering at a sintering temperature of 1500-1700°C for 8-10 hours; hot isostatic pressing sintering: sintering at a sintering temperature of 1500-1750°C, a pressure of 150MPa-300MPa, and sintering for 5-8 hours.

[0020] In the present invention, (Gd, Ce)3(Al, Ga)5O is prepared by using new raw material powder GdGaO3. 12 As the main phase, Al2O3 is a two-phase composite fluorescent ceramic with high thermal conductivity and wide half-height width, which greatly improves the color rendering index and thermal stability of the ceramic. GdGaO3 is used as the raw material in the main phase to avoid Ga 3+ (When Ga2O3 is used as raw material) it cannot replace the Al that enters the garnet 3+ , cannot react normally to form GAGG phase.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The excitation spectrum of the composite ceramic prepared by the present invention is excited at a wavelength of 460nm, with the main peak of the emission spectrum between 567 and 582nm and the half-maximum width between 105 and 120nm. Under the excitation of a blue light LD (1 to 5W) with a wavelength of 455nm, warm white light emission is achieved, with a color temperature of 3800 to 4250K and a color rendering index between 78 and 84; the thermal conductivity of the prepared composite fluorescent ceramic is 20 to 25Wm -1 k -1 Compared with single-phase fluorescent ceramics, the thermal conductivity is increased by 40-69%. When the Al2O3 content is 50%, (Gd, Ce)3(Al, Ga)5O 12 -Al2O3 to achieve the best thermal conductivity 25Wm -1 k -1 , while the color rendering index also reaches 82.

[0023] 2. In the present invention, Al2O3 serves as both the raw material of the fluorescent ceramic and the second phase of the composite ceramic, thus avoiding the introduction of impurity phases. In addition, the second phase Al2O3 can not only improve the thermal conductivity of the ceramic, but also inhibit grain growth, making the main phase particles small and uniform, effectively improving the light extraction rate.

[0024] 3. The composite fluorescent ceramic prepared by the present invention has the characteristics of high color rendering index and high thermal conductivity, which greatly improves the application value and service life of the device. In addition, the preparation method is simple, green and environmentally friendly, and can be used for the industrial production of LD devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 The X-ray diffraction patterns of the complex phase fluorescent ceramics prepared in Examples 1-5 of the present invention;

[0027] Figure 2 This is the emission spectrum of the composite fluorescent ceramics prepared in Examples 1-5 of the present invention under excitation at a wavelength of 460 nm;

[0028] Figure 3 This is a surface SEM image of the complex fluorescent ceramic sample prepared in Example 3 of the present invention;

[0029] Figure 4 Graphs showing the thermal conductivity of the composite fluorescent ceramics prepared in Examples 1-5 of the present invention. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] The raw material powders used in the following examples are all commercially available products with a purity greater than 99.9%.

[0032] Example 1: Preparation of chemical formula (Gd 0.995 Ce 0.005 )3(Al 2.015 Ga 2.985 )O 12 -20% Al2O3 composite fluorescent ceramics, where Al2O3 accounts for 20% of the total mass of the powder

[0033] (1) Set the target product mass to 60.007 g, according to (Gd 0.995 Ce 0.005 )3(Al 2.015 Ga 2.985 )O 12GdGaO3 (42.5474g), CeO2 (0.1338g), and Al2O3 (17.3250g) were weighed as raw material powders, in the stoichiometric ratio of each element in the 20% Al2O3. These powders were blended with 400μL of polyetherimide (a dispersant), followed by anhydrous ethanol. The total mass of the raw material gadolinium gallate, cerium oxide, and aluminum oxide powders to anhydrous ethanol ratio was 1:1.5. The mixture was thoroughly mixed in a planetary ball mill at 180rpm for 20 hours. The milled mixture was then dried in an 80°C oven for 13 hours to obtain a mixed powder. The mixture was then passed through a 200-mesh sieve and sieved twice. The mixed powder was then calcined at 800°C for 5 hours. The mixture was then dried and pressed into a green billet in a steel mold and cold isostatically pressed at 200MPa for 200 seconds to obtain a green billet with a relative density of 50%. Then, pressureless pre-sintering was performed: the sintering temperature was 1550℃, sintering for 8h, and hot isostatic pressing was performed: the sintering temperature was 1600℃, the pressure was 200MPa, and sintering for 5h. Finally, the composite fluorescent ceramic was double-sided polished to obtain Ce flakes. 3+ The activated yellow-green fluorescent ceramic has a diameter of about 17 mm and a thickness of 2 mm, and a dense composite fluorescent ceramic has been obtained.

[0034] The (Gd 0.995 Ce 0.005 )3(Al 2.015 Ga 2.985 )O 12 —20% Al2O3 composite fluorescent ceramics were tested by XRD and showed that the prepared material was composed of GAGG phase and Al2O3 phase. Figure 1 .

[0035] The (Gd 0.995 Ce 0.005 )3(Al 2.015 Ga 2.985 )O 12 When the 20% Al2O3 composite fluorescent ceramic is excited at 460nm, the main peak of its emission spectrum is 582nm. Figure 2 The ceramic emits warm white light under the excitation of high-power blue light LD 3W, with a color temperature of 3800K and a color rendering index of 84; the thermal conductivity is 20.2Wm -1 k -1 ,like Figure 4 .

[0036] Example 2: Preparation of chemical formula (Gd 0.99 Ce 0.01 )3(Al 2.03 Ga 2.97 )O 12-40% Al2O3 composite fluorescent ceramics, where Al2O3 accounts for 40% of the total mass of the powder

[0037] (1) Set the target product mass to 60.010 g, according to (Gd 0.99 Ce 0.01 )3(Al 2.03 Ga 2.97 )O 12 GdGaO3 (31.7810 g), CeO2 (0.2009 g), and Al2O3 (28.0274 g) were weighed as raw material powders, in the stoichiometric ratio of each element in -40% Al2O3. These powders were blended with 400 μL of polyetherimide (a dispersant), followed by anhydrous ethanol. The total mass of the raw material gadolinium gallate, cerium oxide, and aluminum oxide powders to anhydrous ethanol ratio was 1:1.5. The mixture was thoroughly mixed in a planetary ball mill at 180 rpm for 20 hours. The milled mixture was then dried in a 60°C oven for 10 hours to obtain a mixed powder. The mixture was then passed through a 200-mesh sieve and sieved twice. The mixed powder was then calcined at 800°C for 5 hours. The mixture was then dried and pressed into a green billet in a steel mold and cold isostatically pressed at 150 MPa for 240 seconds to obtain a green billet with a relative density of 51%. Then, the composite fluorescent ceramic was double-sided polished to obtain Ce flakes. 3+ The activated yellow-green fluorescent ceramic has a diameter of about 17 mm and a thickness of 2 mm, and a dense composite fluorescent ceramic has been obtained.

[0038] The (Gd 0.99 Ce 0.01 )3(Al 2.03 Ga 2.97 )O 12 -40% Al2O3 composite fluorescent ceramics were tested by XRD and showed that the prepared material was composed of GAGG phase and Al2O3 phase. Figure 1 .

[0039] The (Gd 0.99 Ce 0.01 )3(Al 2.03 Ga 2.97 )O 12 -40% Al2O3 composite fluorescent ceramics have an emission spectrum with a main peak at 576nm under 460nm wavelength excitation. Figure 2 Under the excitation of high-power blue light LD 3W, the ceramic can emit warm white light with a color temperature of 3980K and a color rendering index of 82; the thermal conductivity is 23.2Wm -1 k -1 ,like Figure 4 .

[0040] Example 3: Preparation of chemical formula (Gd 0.985 Ce 0.015 )3(Al 2.045 Ga 2.955 )O 12 -40% Al2O3 composite fluorescent ceramics, where Al2O3 accounts for 40% of the total mass of the powder

[0041] (1) Set the target product mass to 60.0140 g, according to (Gd 0.985 Ce 0.015 )3(Al 2.045 Ga 2.955 )O 12 The raw material powders, GdGaO3 (31.6512g), CeO2 (0.3017g), and Al2O3 (28.0611g), were weighed as the stoichiometric ratio of each element in the 40% Al2O3 mixture. These were then blended with 400μL of polyetherimide (a dispersant), followed by anhydrous ethanol. The total weight ratio of the raw material gadolinium gallate, cerium oxide, and aluminum oxide powders to anhydrous ethanol was 1:2. The mixture was thoroughly mixed using a planetary ball mill at 250rpm for 30 hours. The milled mixture was then dried in a 50°C oven for 12 hours to obtain a mixed powder. The mixture was then passed through a 200-mesh sieve and sieved twice. The mixed powder was then calcined at 600°C for 7 hours. The mixture was then dried and pressed into a green billet in a steel mold and cold isostatically pressed at 170MPa for 200 seconds to obtain a green billet with a relative density of 52%. Then, the composite fluorescent ceramic was double-sided polished to obtain Ce flakes. 3+ The activated yellow-green fluorescent ceramic has a diameter of about 17 mm and a thickness of 2 mm, and a dense composite fluorescent ceramic has been obtained.

[0042] The (Gd 0.985 Ce 0.015 )3(Al 2.045 Ga 2.955 )O 12 -40% Al2O3 composite fluorescent ceramics were tested by XRD and showed that the prepared material was composed of GAGG phase and Al2O3 phase. Figure 1 .

[0043] The (Gd 0.985 Ce 0.015 )3(Al 2.045 Ga 2.955 )O 12-40% Al2O3 composite fluorescent ceramics have an emission spectrum with a main peak at 572nm under 460nm wavelength excitation. Figure 2 The SEM images of the fluorescent ceramic surface show that the grains are dense and the grain size is 2 to 3 μm. Figure 3 The ceramic emits warm white light under the excitation of high-power blue light LD 3W, with a color temperature of 3950K and a color rendering index of 80; the thermal conductivity is 23.3Wm -1 k -1 ,like Figure 4 .

[0044] Example 4: Preparation of chemical formula (Gd 0.985 Ce 0.015 )3(Al 2.045 Ga 2.955 )O 12 -50% Al2O3 composite fluorescent ceramics, where Al2O3 accounts for 50% of the total mass of the powder

[0045] (1) Set the target product mass to 60.012 g, according to (Gd 0.985 Ce 0.015 )3(Al 2.045 Ga 2.955 )O 12 GdGaO3 (26.3760g), CeO2 (0.2514g), and Al2O3 (33.3843g) were weighed as raw material powders, in the stoichiometric ratio of each element in -50% Al2O3. These powders were blended with 400μL of polyetherimide (a dispersant), followed by anhydrous ethanol. The total mass ratio of the raw material gadolinium gallate, cerium oxide, and aluminum oxide powders to anhydrous ethanol was 1:2.5. The mixture was thoroughly mixed using a planetary ball mill at 200rpm for 20 hours. The milled mixture was then dried in an 80°C oven for 9 hours to obtain a mixed powder. The mixture was then passed through a 200-mesh sieve and sieved twice. The mixed powder was then calcined at 800°C for 6 hours. The mixture was then dried and pressed into a green billet in a steel mold and cold isostatically pressed at 200MPa for 200 seconds to obtain a green billet with a relative density of 54%. Then, the composite fluorescent ceramic was double-sided polished to obtain Ce flakes. 3+ The activated yellow-green fluorescent ceramic has a diameter of about 17 mm and a thickness of 2 mm, and a dense composite fluorescent ceramic has been obtained.

[0046] The (Gd 0.985 Ce 0.015 )3(Al 2.045 Ga 2.955 )O 12—50% Al2O3 composite fluorescent ceramics were tested by XRD and showed that the prepared material was composed of GAGG phase and Al2O3 phase. Figure 1 .

[0047] The (Gd 0.985 Ce 0.015 )3(Al 2.045 Ga 2.955 )O 12 When the 50% Al2O3 composite fluorescent ceramic is excited at 460nm, the main peak of its emission spectrum is 568nm. Figure 2 Under the excitation of high-power blue light LD 3W, the ceramic can emit warm white light with a color temperature of 3960K and a color rendering index of 83; the thermal conductivity is 25Wm -1 k -1 ,like Figure 4 .

[0048] Example 5: Preparation of chemical formula (Gd 0.98 Ce 0.02 )3(Al 2.06 Ga 2.94 )O 12 —60% Al2O3 composite fluorescent ceramic, where Al2O3 accounts for 60% of the total mass of the powder

[0049] (1) Set the target product mass to 60.012 g, according to (Gd 0.98 Ce 0.02 )3(Al 2.06 Ga 2.94 )O 12 GdGaO3 (21.0141g), CeO2 (0.2684g), and Al2O3 (38.7299g) were weighed as raw material powders, in the stoichiometric ratio of each element in the 60% Al2O3. These powders were blended with 400μL of polyetherimide (a dispersant), followed by anhydrous ethanol. The total weight ratio of the raw material gadolinium gallate, cerium oxide, and aluminum oxide powders to anhydrous ethanol was 1:3. The mixture was thoroughly mixed using a planetary ball mill at 180rpm for 30 hours. The milled mixture was then dried in an 80°C oven for 8 hours to obtain a mixed powder. The mixture was then passed through a 200-mesh sieve and sieved twice. The mixed powder was then calcined at 800°C for 5 hours. The mixture was then dried and pressed into a green billet in a steel mold and cold isostatically pressed at 150MPa for 400 seconds. Then, the pressureless pre-sintering was carried out at a temperature of 1700℃ for 10 hours, and then the hot isostatic pressing was carried out at a temperature of 1500℃ and a pressure of 300MPa for 5 hours. Finally, the composite fluorescent ceramic was double-sided polished to obtain Ce flakes. 3+ The activated yellow-green fluorescent ceramic has a diameter of about 17 mm and a thickness of 2 mm, and a dense composite fluorescent ceramic has been obtained.

[0050] The (Gd 0.98 Ce 0.02 )3(Al 2.06 Ga 2.94 )O 12 —60% Al2O3 composite fluorescent ceramics were tested by XRD and showed that the prepared material was composed of GAGG phase and Al2O3 phase. Figure 1 .

[0051] The (Gd 0.98 Ce 0.02 )3(Al 2.06 Ga 2.94 )O 12 When the 60% Al2O3 composite fluorescent ceramic is excited at 460nm, the main peak of its emission spectrum is 567nm. Figure 2 Under the excitation of high-power blue light LD 3W, the ceramic can emit warm white light with a color temperature of 4250K and a color rendering index of 78; the thermal conductivity is 24.9Wm -1 k -1 ,like Figure 4 .

[0052] 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, high color rendering index composite fluorescent ceramic for laser lighting, characterized in that: The composite fluorescent ceramic includes (Gd, Ce)3(Al, Ga)5O as the main phase. 12 phase, and the second phase Al2O3 uniformly distributed in the main phase, in which the luminescent ion is Ce 3+ ; Prepared by the following steps: (1) According to the chemical formula (Gd 1-x Ce x )3(Al 2+3x Ga 3-3x )O 12 The stoichiometric ratios of the elements in the mixture are respectively GdGaO3, CeO2, and Al2O3 as the initial raw materials, where x is Ce 3+ Mole percentage of Gd-doped sites 0.005≤x≤0.02 ; Then weigh 20% to 60% of the total mass of the raw material powder as the second phase of the ceramic; (2) After weighing the raw material powder and the dispersant polyetherimide, anhydrous ethanol is added and the mixture is ball-milled. The obtained mixed slurry is dried and sieved, and then the mixed powder is placed in a muffle furnace for calcination; (3) The calcined powder is placed in a mold for dry pressing, and then subjected to cold isostatic pressing to obtain a green body with a relative density of 50% to 55%; (4) sintering the green body at a high temperature, cooling it to room temperature, and then performing double-sided polishing to obtain the composite fluorescent ceramic; wherein the high-temperature sintering is divided into two stages: pressureless pre-sintering and hot isostatic pressing sintering, and the pressureless pre-sintering is sintered at a sintering temperature of 1500-1700°C for 8-10 hours; Hot isostatic pressing sintering: sintering temperature is 1500~1750℃, pressure is 150MPa~300MPa, and sintering time is 5~8h.

2. The high thermal conductivity and high color rendering index composite fluorescent ceramic for laser lighting according to claim 1, characterized in that: In step (2), the amount of the dispersant polyetherimide added is 0.8-1 wt.% of the total mass of the raw material powder, and the mass ratio of the total mass of the raw material powder to anhydrous ethanol is 1:1.5-3.

3. The high thermal conductivity and high color rendering index composite fluorescent ceramic for laser lighting according to claim 1, characterized in that: In step (2), the ball milling speed is 180-250 rpm, and the ball milling time is 15-30 h.

4. The high thermal conductivity and high color rendering index composite fluorescent ceramic for laser lighting according to claim 1, characterized in that: In step (2), the drying temperature is 50-80° C., and the drying time is 8-12 hours.

5. The high thermal conductivity and high color rendering index composite fluorescent ceramic for laser lighting according to claim 1, characterized in that: In step (2), the calcination temperature is raised to 600-800°C at a heating rate of 2-10°C / min at room temperature and kept at this temperature for 5-7 hours.

6. The high thermal conductivity and high color rendering index composite fluorescent ceramic for laser lighting according to claim 1, characterized in that: In step (3), the cold isostatic pressing holding pressure is 150-200 MPa, and the holding time is 200-400 s.

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