A transmissive three-layer composite structure fluorescent ceramic for laser illumination and a preparation method thereof

Abstract

The application discloses a kind of transmission type three-layer composite structure fluorescent ceramic for laser illumination and a preparation method thereof, and the fluorescent ceramic is three-layer composite structure from top to bottom in turn (Re 1‑x Ce x )3Al5O 12 Yellow-green fluorescent layer, transparent high-thermal-conductivity heat-dissipation layer, (A 1‑y Ce y )3(Al 1‑z B z )5O 12 Red fluorescent layer. The preparation method comprises the following steps: placing yellow-green fluorescent ceramic obtained by dry pressing into the bottom of a copper mold, pouring magnesium-aluminum spinel molten liquid into the preheated copper mold, placing red fluorescent ceramic above the molten liquid, and placing the composite structure material obtained after cooling in a muffle furnace for crystallization treatment to obtain the composite structure fluorescent ceramic of yellow-green fluorescent layer / transparent high-thermal-conductivity heat-dissipation layer / red fluorescent layer. The method can realize good connection and combination between different ceramic matrices, and has the advantages of simple process and low cost. The obtained transmission type composite structure fluorescent ceramic can maintain higher luminous intensity at high temperature, and excellent color rendering property can be obtained.

Description

Technical Field

[0001] This invention relates to the field of fluorescent ceramic materials technology, specifically to a transmissive three-layer composite fluorescent ceramic for laser illumination and its preparation method. Background Technology

[0002] Laser-driven white light illumination is considered a next-generation high-brightness solid-state lighting source for applications such as automotive headlights, laser TVs, projectors, medical and health care, and visible light communication. Generally, white light can be obtained by remotely exciting a fluorescence converter using a blue laser diode (LD). Compared to blue light-emitting diodes (LEDs), blue LDs offer advantages such as no efficiency reduction, less beam divergence, and higher output power density. However, the high energy of the laser radiation presents significant challenges to the design and fabrication of the fluorescence converter.

[0003] Traditional resin-phosphorus hybrid phosphor converters suffer from poor heat resistance and low thermal conductivity, leading to thermal corrosion and carbonization under high power density laser excitation, resulting in thermal failure of white light LDs. To address this issue, researchers have developed inorganic conversion materials to avoid carbonization. Single-crystal phosphors possess excellent internal quantum efficiency and thermal management capabilities; however, they typically incur high manufacturing costs. As another option, the inherently weak robustness of fluorescent microcrystalline glass inevitably limits its use. Therefore, fluorescent ceramics, with their good thermal conductivity and high luminescence saturation, are considered a more acceptable choice.

[0004] Furthermore, compared to reflective laser lighting, transmissive laser lighting has advantages such as simpler optical path design, higher light extraction efficiency, and smaller size. However, the key technical challenges currently facing us include: how to improve the utilization rate of incident light while preventing blue laser light from reflecting back to the laser and causing damage; how to improve the extraction efficiency of visible light from fluorescent ceramic devices; how to achieve effective heat dissipation of the transmissive structure; and how to enhance the resistance to laser irradiation while achieving uniform output light to meet the requirements of high-power lighting applications. Summary of the Invention

[0005] The purpose of this invention is to provide a transmissive three-layer composite fluorescent ceramic for laser illumination and its preparation method. This method can achieve good connection and composite between different ceramic matrices, and the process is simple, low in cost, and can be industrialized. The prepared composite fluorescent ceramic can avoid energy transfer and reabsorption between luminescent particles, maintain higher luminous intensity at high temperatures, and obtain higher luminous efficiency and color rendering index.

[0006] To achieve the above objectives, the technical solution adopted by this invention is: a transmissive three-layer composite fluorescent ceramic for laser illumination, wherein the fluorescent ceramic is a three-layer composite structure consisting of a yellow-green fluorescent layer, a transparent high thermal conductivity heat dissipation layer, and a red fluorescent layer from top to bottom, and the chemical formula of the yellow-green fluorescent layer is (Re 1-x Ce x )3Al5O 12 In the formula, Re represents Y or Lu, and x represents Y. 3+ Or Lu 3+ Replace Ce 3+ The molar percentage of the position, 0.0005≤x≤0.005; the transparent high thermal conductivity heat dissipation layer is a magnesium aluminum spinel transparent ceramic layer, its chemical formula is MgO·nAl2O3, where n represents the molar ratio of Al2O3 to MgO, 0.98≤n≤1.5; the chemical formula of the red fluorescent layer is (A 1-y Ce y )3(Al 1-z B z )5O 12 In the formula, A is Y or Lu, B is Mn or Cr, and y is Y 3+ Or Lu 3+ Replace Ce 3+ The mole percentage of the place, 0.001≤y≤0.01, z is Mn 2+ or Cr 3+ Replace Al 3+ The percentage of moles in a given position, 0.001≤z≤0.08.

[0007] Preferably, the thickness of the yellow-green fluorescent layer is 0.03–0.2 mm, the thickness of the transparent high thermal conductivity heat dissipation layer is 0.3–1 mm, and the thickness of the red fluorescent layer is 0.03–0.2 mm.

[0008] The present invention also provides a method for preparing the above-mentioned transmissive three-layer composite fluorescent ceramic for laser illumination, the specific steps of which are as follows:

[0009] S1, Obtain (Re) 1-x Ce x )3Al5O 12 Yellow-green fluorescent ceramics and (A) 1-y Ce y )3(Al 1-z B z )5O 12 Red fluorescent ceramics

[0010] S1-1, using Y2O3 / Lu2O3, Ce2O3 and Al2O3 as raw material powders, according to the chemical formula (Re 1-x Ce x )3Al5O 12Weigh each raw material according to the stoichiometric ratio of the corresponding elements in Y, where x is the stoichiometric ratio of Y. 3+ Or Lu 3+ Replace Ce 3+ The molar percentage of each position, 0.0005≤x≤0.005; after mixing the above raw materials, sintering aid, dispersant, grinding balls, and anhydrous ethanol are added to form a premix, which is then ball-milled, dried, sieved, and impurity removed to obtain (Re 1-x Ce x )3Al5O 12 Fluorescent layer powder;

[0011] Using Y2O3 / Lu2O3, MnCO3 / Cr2O3, Ce2O3 and Al2O3 as raw material powders, according to chemical (A 1-y Ce y )3(Al 1-z B z )5O 12 Weigh each raw material according to the stoichiometric ratio of the corresponding elements, where y is Y. 3+ Or Lu 3+ Replace Ce 3+ The mole percentage of the position, z is Mn 2+ or Cr 3+ Replace Al 3+ The molar percentage of each position is 0.001≤y≤0.01, 0.001≤z≤0.08; after mixing the above raw materials, sintering aid, dispersant, grinding balls, and anhydrous ethanol are added to form a premix, which is then ball-milled, dried, sieved, and impurity removed to obtain (A). 1-y Ce y )3(Al 1-z B z )5O 12 Fluorescent layer powder;

[0012] S1-2, (Re) 1-x Ce x )3Al5O 12 Fluorescent layer powder, (A) 1-y Ce y )3(Al 1-z B z )5O 12 The fluorescent layer powders were sequentially subjected to dry pressing and cold isostatic pressing, and then calcined to obtain (Re) 1-x Ce x )3Al5O 12 Single-layer ceramic green body and (A) 1-y Ce y )3(Al 1-z B z )5O 12 Single-layer ceramic blank;

[0013] S1-3, The single-layer green blank obtained in step S1-2 is prepared according to (Re 1-x Ce x )3Al5O 12 Single-layer ceramic green body and (A) 1-y Ce y )3(Al 1-z B z )5O 12 Single-layer ceramic blanks were sintered in a vacuum furnace, and then the sintered samples were air-annealed in a muffle furnace. After cutting and polishing, they were obtained as (Re 1-x Ce x )3Al5O 12 Yellow-green fluorescent ceramics and (A) 1- y Ce y )3(Al 1-z B z )5O 12 Red fluorescent ceramics;

[0014] S2. Weigh high-purity MgO and Al2O3 powders according to the chemical formula MgO·nAl2O3 as initial raw materials, where n represents the molar ratio of Al2O3 to MgO, 0.98≤n≤1.5. Mix the weighed initial raw materials, nucleating agent, network forming body and anhydrous ethanol in a certain proportion and place them in a ball mill jar. Ball mill to obtain mixed powder.

[0015] S3. Place the mixed powder from step S2 into an alumina crucible and put it into a lifting furnace. Heat it until it is completely melted to obtain a molten liquid. Stir the molten liquid with a quartz rod.

[0016] S4. Take the (Re) obtained in step S1 1-x Ce x )3Al5O 12 Yellow-green fluorescent ceramic is placed at the bottom of the copper mold. Then, the molten liquid obtained in step S3 is transferred from the lifting furnace and poured into the preheated copper mold. Then, the (A) obtained in step S1 is poured into the mold. 1-y Ce y )3(Al 1- z B z )5O 12 A composite material of yellow-green fluorescent layer ceramic / magnesium aluminum spinel glass / red fluorescent layer ceramic is obtained by placing red fluorescent ceramic above the molten liquid and cooling it.

[0017] S5. The composite material from step S4 is placed in a muffle furnace for crystallization treatment to obtain a three-layer composite fluorescent ceramic with a yellow-green fluorescent layer, a transparent high thermal conductivity heat dissipation layer, and a red fluorescent layer.

[0018] Preferably, in step S1-1, the sintering aid is MgO and TEOS, and the amount added is 0.2-0.7 wt.% and 0.4-0.6 wt.% of the total mass of the raw material powder, respectively; the dispersant is PEI, and the amount added is 0.2-0.5 wt.% of the total mass of the raw material powder.

[0019] Preferably, in steps S1-2, the dry pressing pressure is 15-20 MPa, and the holding pressure is 30-60 s; the cold isostatic pressing pressure is 150-250 MPa, and the time is 4-6 min; the calcination temperature is 600-900℃, and the time is 5-8 h.

[0020] Preferably, in steps S1-3, the vacuum sintering temperature is 1740-1780℃ and the holding time is 6-10h; the air annealing temperature is 1400-1500℃ and the holding time is 8-12h.

[0021] Preferably, in step S2, the ball milling speed is 160–190 r / min, and the ball milling time is 10–20 h; the nucleating agent is P2O5, and the amount added is 0.1–1.8 wt.% of the total mass of MgO powder and Al2O3 powder; the network forming body is SiO2, and the amount added is 0.1–1.5 wt.% of the total mass of MgO powder and Al2O3 powder.

[0022] Preferably, in step S3, the melting temperature is 2100–2300°C.

[0023] Preferably, in step S4, the preheating temperature of the copper mold is 500-700°C.

[0024] Preferably, in step S5, the crystallization temperature is 1100–1300℃ and the crystallization time is 1–3 hours.

[0025] Compared with existing technical solutions, the present invention has the following advantages:

[0026] (1) The matrix of the luminescent ions in this invention is a ceramic material with high thermal conductivity, which is suitable for future high-power and high-brightness laser lighting; in addition, this invention prepares a highly transparent and thermally conductive magnesium aluminum spinel transparent ceramic as a heat dissipation layer by amorphous crystallization method, and sinterses Ce on both sides of the spinel. 3+ and Mn 2+ / Cr 3+ The fluorescent ceramic replacing the garnet host solves problems such as photon reabsorption, backscattering, and thermal conduction in the fluorescent layer, enabling the composite ceramic to maintain higher luminescence intensity at high temperatures and achieve higher luminescence efficiency and color index.

[0027] (2) This invention uses dry pressing combined with amorphous crystallization to prepare composite fluorescent ceramics. The amorphous crystallization method is used to achieve the connection and composite of three-layer ceramic materials. The process is simple, no need to bond with glass, low requirements for powder, molding and sintering equipment, short preparation cycle, obvious economic benefits, green and environmentally friendly, and can be applied to industrial production.

[0028] (3) The three-layer composite fluorescent ceramic obtained in this invention, when excited by 450nm blue light, has a laser excitation power density of 30W / mm². 2 At that time, the maximum luminous efficiency was 220-260 lm / W, the color temperature was 3500-4500 K, the color rendering index was 83-89, and the emission intensity was only lost by 2.4-5.2% at 150℃. Attached Figure Description

[0029] Figure 1 This is a schematic diagram illustrating the structure, luminescence, and thermal conduction of the composite fluorescent ceramic of the present invention;

[0030] Appendix Figure 1 In the middle: 1. Yellow-green fluorescent layer, 2. Transparent high thermal conductivity heat dissipation layer, 3. Red fluorescent layer;

[0031] Figure 2 The graph shows the changes in luminescence efficiency and color index of the composite fluorescent ceramic prepared in Example 3 of the present invention under 450 nm excitation.

[0032] Figure 3 This is a graph showing the change in luminescence intensity of the composite fluorescent ceramic prepared in Example 3 of the present invention as a function of temperature. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Example 1

[0035] A transmissive three-layer composite fluorescent ceramic for laser illumination, the structure of which is as follows: Figure 1 As shown, the fluorescent ceramic has a three-layer composite structure consisting of a yellow-green fluorescent layer, a transparent high thermal conductivity heat dissipation layer, and a red fluorescent layer, from top to bottom. The chemical formula of the yellow-green fluorescent layer is (Y). 0.9995 Ce 0.0005 )3Al5O 12 The transparent, high thermal conductivity heat dissipation layer is a magnesium aluminum spinel transparent ceramic layer with the chemical formula MgO·0.98Al2O3; the red fluorescent layer has the chemical formula (Y). 0.999 Ce 0.001 )3(Al 0.999 Mn 0.001 )5O 12The thickness of the yellow-green fluorescent layer is 0.2 mm, the thickness of the transparent high thermal conductivity heat dissipation layer is 0.3 mm, and the thickness of the red fluorescent layer is 0.2 mm.

[0036] The specific steps for preparing the above-mentioned composite fluorescent ceramic are as follows:

[0037] S1, obtain (Y) 0.9995 Ce 0.0005 )3Al5O 12 Yellow-green fluorescent ceramics and (Y) 0.999 Ce 0.001 )3(Al 0.999 Mn 0.001 )5O 12 Red fluorescent ceramics

[0038] S1-1, according to the chemical formula (Y) 0.9995 Ce 0.0005 )3Al5O 12 The stoichiometric ratios of each element were determined by weighing 60.001 g of high-purity Y₂O₃ (34.214 g), Al₂O₃ (25.761 g), and CeO₂ (0.026 g) raw material powders. These raw materials were mixed, and sintering aids (0.14 g MgO and 0.27 g TEOS) and dispersant (0.14 g PEI) were added. Anhydrous ethanol was used as the solvent, and alumina balls were used as the ball milling medium. The accurately weighed raw material powders were placed in a ball mill jar and ball-milled at 180 r / min for 15 h to obtain a uniformly mixed slurry. After drying, the ball-milled slurry was sieved to remove impurities, yielding (Y₂O₃) as the final product. 0.9995 Ce 0.0005 )3Al5O 12 Fluorescent layer powder;

[0039] According to the chemical formula (Y) 0.999 Ce 0.001 )3(Al 0.999 Mn 0.001 )5O 12 The stoichiometric ratios of each element were determined by weighing out 60.021 g of high-purity Y₂O₃ (34.185 g), CeO₂ (0.052 g), Al₂O₃ (25.726 g), and MnCO₃ (0.058 g) raw material powders. These raw materials were mixed, and sintering aids (0.14 g MgO and 0.27 g TEOS) and dispersant (0.14 g PEI) were added. Anhydrous ethanol was used as the solvent, and alumina balls were used as the ball milling medium. The accurately weighed raw material powders were placed in a ball mill jar and ball-milled at 180 r / min for 15 h to obtain a uniformly mixed slurry. After drying the ball-milled slurry, it was sieved to remove impurities, yielding (Y₂O₃) as the final product. 0.999 Ce 0.001 )3(Al 0.999 Mn0.001 )5O 12 Fluorescent layer powder;

[0040] S1-2, (Y) 0.9995 Ce 0.0005 )3Al5O 12 Fluorescent layer powder, (Y 0.999 Ce 0.001 )3(Al 0.999 Mn 0.001 )5O 12 The fluorescent layer powders were poured into molds and pressed at 15 MPa for 30 seconds. After sealing, the green blanks were cold isostatically pressed at 150 MPa for 4 minutes, and finally calcined at 600℃ for 5 hours to obtain (Y) 0.9995 Ce 0.0005 )3Al5O 12 Single-layer ceramic green body and (Y) 0.999 Ce 0.001 )3(Al 0.999 Mn 0.001 )5O 12 Single-layer ceramic blank;

[0041] S1-3, The single-layer green blank obtained in step S1-2 is prepared according to (Y) 0.9995 Ce 0.0005 )3Al5O 12 Single-layer ceramic green body and (Y) 0.999 Ce 0.001 )3(Al 0.999 Mn 0.001 )5O 12 The ceramic blanks were sintered in a vacuum furnace at 1740℃ for 6 hours. The sintered samples were then air-annealed in a muffle furnace at 1400℃ for 8 hours. After cutting and polishing, (Y) were obtained. 0.9995 Ce 0.0005 )3Al5O 12 Yellow-green fluorescent ceramics and (Y) 0.999 Ce 0.001 )3(Al 0.999 Mn 0.001 )5O 12 Red fluorescent ceramics;

[0042] S2. Weigh out 60g of raw material powder, including 17.245g of high-purity MgO and 42.756g of Al2O3 powder, according to the molar ratio in the chemical formula MgO·0.98Al2O3. Mix the weighed initial raw materials, nucleating agent (0.06g P2O5), network forging agent (0.06g SiO2), and anhydrous ethanol in a certain proportion and place them in a ball mill jar. Use planetary ball milling at a speed of 160r / min for 10h to obtain a mixed slurry.

[0043] S3. Place the mixed slurry from step S2 into an alumina crucible and put it into a lifting furnace. Heat the slurry until it is completely melted to obtain a molten liquid. The melting temperature is 2100℃. Stir the molten liquid with a quartz rod.

[0044] S4, take the (Y) obtained in step S1 0.9995 Ce 0.0005 )3Al5O 12 Yellow-green fluorescent ceramic is placed at the bottom of a copper mold. Then, the molten liquid obtained in step S3 is transferred from the lifting furnace and poured into a copper mold preheated to 500°C. Finally, the (Y) fluorescent ceramic obtained in step S1 is poured into the mold. 0.999 Ce 0.001 )3(Al 0.999 Mn 0.001 )5O 12 A composite material of yellow-green fluorescent layer ceramic / magnesium aluminum spinel glass / red fluorescent layer ceramic is obtained by placing red fluorescent ceramic above the molten liquid and cooling it.

[0045] S5. The composite material from step S4 is placed in a muffle furnace for crystallization treatment at a temperature of 1100℃ for 1 hour to obtain a three-layer composite fluorescent ceramic with a yellow-green fluorescent layer, a transparent high thermal conductivity heat dissipation layer, and a red fluorescent layer.

[0046] The composite fluorescent ceramic prepared in this embodiment, when excited by 450nm blue light with a laser excitation power density of 30W / mm², exhibits excellent performance. 2 At that time, the maximum luminous efficiency was 220 lm / W, the color temperature was 4500K, the color rendering index was 83, and the emission intensity was only lost by 5.1% at 150℃.

[0047] Example 2

[0048] A transmissive three-layer composite fluorescent ceramic for laser illumination, the structure of which is as follows: Figure 1 As shown, the fluorescent ceramic has a three-layer composite structure consisting of a yellow-green fluorescent layer, a transparent high thermal conductivity heat dissipation layer, and a red fluorescent layer, from top to bottom. The chemical formula of the yellow-green fluorescent layer is (Lu). 0.999 Ce 0.001 )3Al5O 12The transparent, high thermal conductivity heat dissipation layer is a magnesium aluminum spinel transparent ceramic layer with the chemical formula MgO·1.2Al2O3; the red fluorescent layer has the chemical formula (Lu 0.995 Ce 0.005 )3(Al 0.99 Cr 0.01 )5O 12 The thickness of the yellow-green fluorescent layer is 0.1 mm, the thickness of the transparent high thermal conductivity heat dissipation layer is 0.6 mm, and the thickness of the red fluorescent layer is 0.1 mm.

[0049] The specific steps for preparing the above-mentioned composite fluorescent ceramic are as follows:

[0050] S1, Obtain (Lu) 0.999 Ce 0.001 )3Al5O 12 Yellow-green fluorescent ceramics and (Lu 0.995 Ce 0.005 )3(Al 0.99 Cr 0.01 )5O 12 Red fluorescent ceramics

[0051] S1-1, according to the chemical formula (Lu 0.999 Ce 0.001 )3Al5O 12 The stoichiometric ratios of each element were determined by weighing 60.001 g of high-purity Lu₂O₃ (42.008 g), Al₂O₃ (17.957 g), and CeO₂ (0.036 g) raw material powders. These raw materials were mixed, and sintering aids (0.312 g MgO and 0.312 g TEOS) and dispersant (0.187 g PEI) were added. Anhydrous ethanol was used as the solvent, and alumina balls were used as the ball milling medium. The accurately weighed raw material powders were placed in a ball mill jar and ball-milled at 180 r / min for 15 h to obtain a uniformly mixed slurry. After drying, the ball-milled slurry was sieved to remove impurities, yielding (Lu₂O₃) powder. 0.999 Ce 0.001 )3Al5O 12 Fluorescent layer powder;

[0052] According to the chemical formula (Lu 0.995 Ce 0.005 )3(Al 0.99 Cr 0.01 )5O 12The stoichiometric ratios of each element were determined by weighing 60.008 g of high-purity Lu₂O₃ (41.799 g), CeO₂ (0.182 g), Al₂O₃ (17.760 g), and Cr₂O₃ (0.267 g) raw material powders. These raw materials were mixed, and sintering aids (0.312 g MgO and 0.312 g TEOS) and dispersant (0.187 g PEI) were added. Anhydrous ethanol was used as the solvent, and alumina balls were used as the ball milling medium. The accurately weighed raw material powders were placed in a ball mill jar and ball-milled at 180 r / min for 15 h to obtain a uniformly mixed slurry. After drying, the ball-milled slurry was sieved to remove impurities, yielding (Lu₂O₃)... 0.995 Ce 0.005 )3(Al 0.99 Cr 0.01 )5O 12 Fluorescent layer powder;

[0053] S1-2, (Lu) 0.999 Ce 0.001 )3Al5O 12 Fluorescent layer powder, (Lu 0.995 Ce 0.005 )3(Al 0.99 Cr 0.01 )5O 12 The fluorescent layer powders were poured into molds and pressed under 18 MPa pressure for 45 seconds. After sealing, the green blanks were cold isostatically pressed at 200 MPa for 5 minutes, and finally calcined at 750℃ for 7 hours to obtain (Lu) 0.999 Ce 0.001 )3Al5O 12 Single-layer ceramic blank and (Lu 0.995 Ce 0.005 )3(Al 0.99 Cr 0.01 )5O 12 Single-layer ceramic blank;

[0054] S1-3, The single-layer green blank obtained in step S1-2 is prepared according to (Lu 0.999 Ce 0.001 )3Al5O 12 Single-layer ceramic blank and (Lu 0.995 Ce 0.005 )3(Al 0.99 Cr 0.01 )5O 12 The ceramic blanks were sintered in a vacuum furnace at 1760℃ for 8 hours. The sintered samples were then air-annealed in a muffle furnace at 1450℃ for 10 hours. After cutting and polishing, the resulting samples were (Lu) 0.999 Ce0.001 )3Al5O 12 Yellow-green fluorescent ceramics and (Lu 0.995 Ce 0.005 )3(Al 0.99 Cr 0.01 )5O 12 Red fluorescent ceramics;

[0055] S2. Weigh out 60g of raw material powder, including 14.867g of high-purity MgO and 45.133g of Al2O3 powder, according to the molar ratio in the chemical formula MgO·1.2Al2O3. Mix the weighed initial raw materials, nucleating agent (1.02g P2O5), network forging body (0.6g SiO2), and anhydrous ethanol in a certain proportion and place them in a ball mill jar. Use planetary ball milling at a speed of 180r / min for 15h to obtain a mixed slurry.

[0056] S3. Place the mixed slurry from step S2 into an alumina crucible and put it into a lifting furnace. Heat the slurry until it is completely melted to obtain a molten liquid. The melting temperature is 2200℃. Stir the molten liquid with a quartz rod.

[0057] S4, take the (Lu) obtained in step S1 0.999 Ce 0.001 )3Al5O 12 Yellow-green fluorescent ceramic is placed at the bottom of a copper mold. Then, the molten liquid obtained in step S3 is transferred from the lifting furnace and poured into a copper mold preheated to 600°C. Finally, the (Lu) obtained in step S1 is... 0.995 Ce 0.005 )3(Al 0.99 Cr 0.01 )5O 12 A composite material of yellow-green fluorescent layer ceramic / magnesium aluminum spinel glass / red fluorescent layer ceramic is obtained by placing red fluorescent ceramic above the molten liquid and cooling it.

[0058] S5. The composite material from step S4 is placed in a muffle furnace for crystallization treatment at a temperature of 1200℃ for 2 hours to obtain a three-layer composite fluorescent ceramic with a yellow-green fluorescent layer, a transparent high thermal conductivity heat dissipation layer, and a red fluorescent layer.

[0059] The composite fluorescent ceramic prepared in this embodiment, when excited by 450nm blue light with a laser excitation power density of 30W / mm², exhibits excellent performance. 2 At that time, the maximum luminous efficiency was 240 lm / W, the color temperature was 4000K, the color rendering index was 85, and the emission intensity was only lost by 3.7% at 150℃.

[0060] Example 3

[0061] A transmissive three-layer composite fluorescent ceramic for laser illumination, the structure of which is as follows: Figure 1 As shown, the fluorescent ceramic has a three-layer composite structure consisting of a yellow-green fluorescent layer, a transparent high thermal conductivity heat dissipation layer, and a red fluorescent layer, from top to bottom. The chemical formula of the yellow-green fluorescent layer is (Y). 0.995 Ce 0.005 )3Al5O 12 The transparent high thermal conductivity heat dissipation layer is a magnesium aluminum spinel transparent ceramic layer with the chemical formula MgO·1.5Al2O3; the chemical formula of the red fluorescent layer is (Y 0.99 Ce 0.01 )3(Al 0.92 Mn 0.08 )5O 12 The thickness of the yellow-green fluorescent layer is 0.03 mm, the thickness of the transparent high thermal conductivity heat dissipation layer is 1 mm, and the thickness of the red fluorescent layer is 0.03 mm.

[0062] The specific steps for preparing the above-mentioned composite fluorescent ceramic are as follows:

[0063] S1, obtain (Y) 0.995 Ce 0.005 )3Al5O 12 Yellow-green fluorescent ceramics and (Y) 0.99 Ce 0.01 )3(Al 0.92 Mn 0.08 )5O 12 Red fluorescent ceramics

[0064] S1-1, according to the chemical formula (Y) 0.995 Ce 0.005 )3Al5O 12 The stoichiometric ratios of each element were determined by weighing 60.012 g of high-purity Y₂O₃ (34.020 g), Al₂O₃ (25.731 g), and CeO₂ (0.261 g) raw material powders. These raw materials were mixed, and sintering aids (0.4 g MgO and 0.35 g TEOS) and dispersant (0.3 g PEI) were added. Anhydrous ethanol was used as the solvent, and alumina balls were used as the ball milling medium. The accurately weighed raw material powders were placed in a ball mill jar and ball-milled at 180 r / min for 15 h to obtain a uniformly mixed slurry. The ball-milled slurry was dried, sieved, and impurities were removed to obtain (Y₂O₃) powder. 0.995 Ce 0.005 )3Al5O 12 Fluorescent layer powder;

[0065] According to the chemical formula (Y) 0.99 Ce 0.01 )3(Al 0.92 Mn 0.08 )5O12 The stoichiometric ratios of each element were determined by weighing out 61.449 g of high-purity Y₂O₃ (33.182 g), CeO₂ (0.511 g), Al₂O₃ (23.206 g), and MnCO₃ (4.550 g) raw material powders. These raw materials were mixed, and sintering aids (0.4 g MgO and 0.35 g TEOS) and dispersant (0.3 g PEI) were added. Anhydrous ethanol was used as the solvent, and alumina balls were used as the ball milling medium. The accurately weighed raw material powders were placed in a ball mill jar and ball-milled at 180 r / min for 15 h to obtain a uniformly mixed slurry. After drying, the ball-milled slurry was sieved to remove impurities, yielding (Y₂O₃)... 0.99 Ce 0.01 )3(Al 0.92 Mn 0.08 )5O 12 Fluorescent layer powder;

[0066] S1-2, (Y) 0.995 Ce 0.005 )3Al5O 12 Fluorescent layer powder, (Y 0.99 Ce 0.01 )3(Al 0.92 Mn 0.08 )5O 12 Fluorescent layer powders were poured into molds and pressed under 20 MPa pressure for 60 seconds. After sealing, the green blanks were cold isostatically pressed at 250 MPa for 6 minutes, and finally calcined at 900℃ for 8 hours to obtain (Y) 0.995 Ce 0.005 )3Al5O 12 Single-layer ceramic green body and (Y) 0.99 Ce 0.01 )3(Al 0.92 Mn 0.08 )5O 12 Single-layer ceramic blank;

[0067] S1-3, The single-layer green blank obtained in step S1-2 is prepared according to (Y) 0.995 Ce 0.005 )3Al5O 12 Single-layer ceramic green body and (Y) 0.99 Ce 0.01 )3(Al 0.92 Mn 0.08 )5O 12 The ceramic blanks were sintered in a vacuum furnace at 1780℃ for 10 hours. The sintered samples were then air-annealed in a muffle furnace at 1500℃ for 12 hours. After cutting and polishing, (Y) were obtained. 0.995 Ce0.005 )3Al5O 12 Yellow-green fluorescent ceramics and (Y) 0.99 Ce 0.01 )3(Al 0.92 Mn 0.08 )5O 12 Red fluorescent ceramics;

[0068] S2. Weigh out 60g of raw material powder, including 12.514g of high-purity MgO and 47.486g of Al2O3 powder, according to the molar ratio in the chemical formula MgO·1.5Al2O3. Mix the weighed initial raw materials, nucleating agent (1.08g P2O5), network forging body (0.9g SiO2), and anhydrous ethanol in a certain proportion and place them in a ball mill jar. Use planetary ball milling at a speed of 190r / min for 20h to obtain a mixed slurry.

[0069] S3. Place the mixed slurry from step S2 into an alumina crucible and put it into a lifting furnace. Heat the slurry until it is completely melted to obtain a molten liquid. The melting temperature is 2300℃. Stir the molten liquid with a quartz rod.

[0070] S4, take the (Y) obtained in step S1 0.995 Ce 0.005 )3Al5O 12 Yellow-green fluorescent ceramic is placed at the bottom of a copper mold. Then, the molten liquid obtained in step S3 is transferred from the lifting furnace and poured into a copper mold preheated to 700°C. Finally, the (Y) fluorescent ceramic obtained in step S1 is poured into the mold. 0.99 Ce 0.01 )3(Al 0.92 Mn 0.08 )5O 12 A composite material of yellow-green fluorescent layer ceramic / magnesium aluminum spinel glass / red fluorescent layer ceramic is obtained by placing red fluorescent ceramic above the molten liquid and cooling it.

[0071] S5. The composite material from step S4 is placed in a muffle furnace for crystallization treatment at a temperature of 1300℃ for 3 hours to obtain a three-layer composite fluorescent ceramic with a yellow-green fluorescent layer, a transparent high thermal conductivity heat dissipation layer, and a red fluorescent layer.

[0072] Figure 2 It showed (Y) 0.995 Ce 0.005 )3Al5O 12 / MgO·1.5Al2O3 / (Y 0.99 Ce 0.01 )3(Al 0.92 Mn 0.08 )5O 12The graph shows the changes in luminescence efficiency and color index of the composite fluorescent ceramic under 450 nm excitation, where the efficiency increases with laser power density from 5 W / mm². 2 Increased to 30W / mm 2 The luminous efficacy (LE) initially increases and then reaches saturation at 260 lm / W, while the color rendering index (CRI) shows very little variation, fluctuating around 89, indicating excellent color stability. Furthermore, as... Figure 3 As shown, the fluorescent ceramic exhibits extremely low thermal quenching, maintaining 97.6% of its initial luminescence intensity even at 150°C, with a decay loss of only 2.4%.

[0073] The composite fluorescent ceramic prepared in this embodiment, when excited by 450nm blue light with a laser excitation power density of 30W / mm², exhibits excellent performance. 2 At that time, the maximum luminous efficiency was 260 lm / W, the color temperature was 3500 K, the color rendering index was 89, and the emission intensity was only reduced by 2.4% at 150℃.

[0074] The above description is merely 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 those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a transmissive three-layer composite fluorescent ceramic for laser illumination, characterized in that, The fluorescent ceramic has a three-layer composite structure consisting of a yellow-green fluorescent layer, a transparent high thermal conductivity heat dissipation layer, and a red fluorescent layer, from top to bottom. The chemical formula of the yellow-green fluorescent layer is (Re). 1-x Ce x )3Al5O 12 In the formula, Re is either Y or Lu. x For Y 3+ Or Lu 3+ Replace Ce 3+ The molar percentage of the position, 0.0005≤x≤0.005; the transparent high thermal conductivity heat dissipation layer is a magnesium aluminum spinel transparent ceramic layer, its chemical formula is MgO·nAl2O3, where n represents the molar ratio of Al2O3 to MgO, 0.98≤n≤1.5; the chemical formula of the red fluorescent layer is (A 1-y Ce y )3(Al 1-z B z )5O 12 In the formula, A is Y or Lu, and B is Mn or Cr. y For Y 3+ Or Lu 3+ Replace Ce 3+ The mole percentage of the place, 0.001≤y≤0.01, z is Mn 2+ or Cr 3+ Replace Al 3+ The molar percentage of the position is 0.001≤z≤0.08; the thickness of the yellow-green fluorescent layer is 0.03~0.2mm, the thickness of the transparent high thermal conductivity heat dissipation layer is 0.3~1mm, and the thickness of the red fluorescent layer is 0.03~0.2mm; The specific steps of the preparation method are as follows: S1, obtaining (Re 1-x Ce x )3Al5O 12 yellow-green fluorescent ceramic and (A 1-y Ce y )3(Al 1-z B z )5O 12 red fluorescent ceramic S1-1, using Y2O3 / Lu2O3, Ce2O3 and Al2O3 as raw material powders, according to the chemical formula (Re 1-x Ce x )3Al5O 12 Weigh each raw material according to the stoichiometric ratio of the corresponding elements, where x For Y 3+ Or Lu 3+ Replace Ce 3+ The molar percentage of each position, 0.0005≤x≤0.005; after mixing the above raw materials, sintering aid, dispersant, grinding balls, and anhydrous ethanol are added to form a premix, which is then ball-milled, dried, sieved, and impurity removed to obtain (Re 1-x Ce x )3Al5O 12 Fluorescent layer powder; Using Y2O3 / Lu2O3, MnCO3 / Cr2O3, Ce2O3 and Al2O3 as raw material powders, according to chemical (A 1-y Ce y )3(Al 1-z B z )5O 12 Weigh each raw material according to the stoichiometric ratio of the corresponding elements, where y For Y 3+ Or Lu 3+ Replace Ce 3+ The mole percentage of the position, z is Mn 2+ or Cr 3+ Replace Al 3+ The molar percentage of each position is 0.001≤y≤0.01, 0.001≤z≤0.08; after mixing the above raw materials, sintering aid, dispersant, grinding balls, and anhydrous ethanol are added to form a premix, which is then ball-milled, dried, sieved, and impurity removed to obtain (A). 1-y Ce y )3(Al 1-z B z )5O 12 Fluorescent layer powder; S1-2, (Re) 1-x Ce x )3Al5O 12 Fluorescent layer powder, (A) 1-y Ce y )3(Al 1-z B z )5O 12 The fluorescent layer powders were sequentially subjected to dry pressing and cold isostatic pressing, and then calcined to obtain (Re) 1-x Ce x )3Al5O 12 Single-layer ceramic green body and (A) 1-y Ce y )3(Al 1- z B z )5O 12 Single-layer ceramic blank; S1-3, The single-layer green blank obtained in step S1-2 is prepared according to (Re 1-x Ce x )3Al5O 12 Single-layer ceramic green body and (A) 1- y Ce y )3(Al 1-z B z )5O 12 Single-layer ceramic blanks were sintered in a vacuum furnace, and then the sintered samples were air-annealed in a muffle furnace. After cutting and polishing, they were obtained as (Re 1-x Ce x )3Al5O 12 Yellow-green fluorescent ceramics and (A) 1-y Ce y )3(Al 1-z B z )5O 12 Red fluorescent ceramics; S2. Weigh high-purity MgO and Al2O3 powders according to the chemical formula MgO·nAl2O3 as initial raw materials, where n represents the molar ratio of Al2O3 to MgO, 0.98≤n≤1.

5. Mix the weighed initial raw materials, nucleating agent, network forming body and anhydrous ethanol in a certain proportion and place them in a ball mill jar. Ball mill to obtain a mixed slurry. S3. Place the mixed slurry from step S2 into an alumina crucible and put it into a lifting furnace. Heat the slurry until it is completely melted to obtain a molten liquid. Stir the molten liquid with a quartz rod. S4. Take the (Re) obtained in step S1 1-x Ce x )3Al5O 12 Yellow-green fluorescent ceramic is placed at the bottom of the copper mold. Then, the molten liquid obtained in step S3 is transferred from the lifting furnace and poured into the preheated copper mold. Then, the (A) obtained in step S1 is poured into the mold. 1-y Ce y )3(Al 1-z B z )5O 12 A composite material of yellow-green fluorescent layer ceramic / magnesium aluminum spinel glass / red fluorescent layer ceramic is obtained by placing red fluorescent ceramic above the molten liquid and cooling it. S5. The composite material from step S4 is placed in a muffle furnace for crystallization treatment to obtain a three-layer composite fluorescent ceramic with a yellow-green fluorescent layer, a transparent high thermal conductivity heat dissipation layer, and a red fluorescent layer; the crystallization treatment temperature is 1100~1300℃ and the crystallization time is 1~3h.

2. The method for preparing a transmissive three-layer composite fluorescent ceramic for laser illumination according to claim 1, characterized in that, In step S1-1, the sintering aids are MgO and TEOS, and the amounts added are 0.2~0.7wt.% and 0.4~0.6wt.% of the total mass of the raw material powder, respectively; the dispersant is PEI, and the amount added is 0.2~0.5wt.% of the total mass of the raw material powder.

3. The method for preparing a transmissive three-layer composite fluorescent ceramic for laser illumination according to claim 1 or 2, characterized in that, In steps S1-2, the dry pressing pressure is 15~20MPa, and the holding pressure is 30~60s; the cold isostatic pressing pressure is 150~250MPa, and the time is 4~6min; the calcination temperature is 600~900℃, and the time is 5~8h.

4. The method for preparing a transmissive three-layer composite fluorescent ceramic for laser illumination according to claim 1 or 2, characterized in that, In steps S1-3, the vacuum sintering temperature is 1740~1780℃ and the holding time is 6~10h; the air annealing temperature is 1400~1500℃ and the holding time is 8~12h.

5. A method for preparing a transmissive three-layer composite fluorescent ceramic for laser illumination according to claim 1 or 2, characterized in that, In step S2, the ball milling speed is 160~190 r / min, and the ball milling time is 10~20 h; the nucleating agent is P2O5, and the amount added is 0.1~1.8 wt.% of the total mass of MgO powder and Al2O3 powder; the network forming body is SiO2, and the amount added is 0.1~1.5 wt.% of the total mass of MgO powder and Al2O3 powder.

6. A method for preparing a transmissive three-layer composite fluorescent ceramic for laser illumination according to claim 1 or 2, characterized in that, In step S3, the melting temperature is 2100~2300℃.

7. A method for preparing a transmissive three-layer composite fluorescent ceramic for laser illumination according to claim 1 or 2, characterized in that, In step S4, the preheating temperature of the copper mold is 500~700℃.

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