Fluorescent ceramic, preparation method thereof and light source device

Abstract

The fluorescent ceramic provided by the embodiment of the invention comprises a fluorescent phase, a toughened ceramic phase and pores, the fluorescent phase comprises a plurality of fluorescent particles, the toughened ceramic phase comprises a plurality of zirconium oxide toughened aluminum oxide particles, the fluorescent particles are dispersed in the toughened ceramic phase, and the pores are dispersed in the toughened ceramic phase. At least part of the pores are dispersed at the junction of at least one of the zirconium oxide toughened aluminum oxide particles and the fluorescent particles. The toughened ceramic phase is mixed in the fluorescent phase, and the toughened ceramic phase has the characteristics of high thermal conductivity, mechanical enhancement and the like, so that the thermal conductivity of the fluorescent ceramic module is further improved, and high-efficiency fluorescence conversion under high power density is met. The toughened ceramic phase can also increase light scattering of exciting light and improve the light extraction efficiency of the fluorescent ceramic. The toughened ceramic phase can also effectively improve the mechanical property of the fluorescent ceramic with the porous structure, better fracture toughness is obtained, and the reliability is higher. The invention also provides a preparation method of the fluorescent ceramic and a light source device.

Description

Technical Field

[0001] The present application relates to the technical field of light source equipment, and in particular to a fluorescent ceramic and a preparation method thereof, and a light source device. Background Art

[0002] As projection devices become increasingly common, laser display light sources are required to be smaller, higher in brightness, and with a wider color gamut. As the size of the internal phosphor converters shrinks, the laser power density they must withstand increases, placing higher demands on the heat resistance and thermal conductivity of the encapsulated phosphor converters.

[0003] Existing projection devices use porous pure garnet-phase fluorescent ceramics as their fluorescence conversion device. Because the luminescence absorption centers are evenly dispersed within this ceramic phase, they can effectively reduce light absorption density. However, due to the relatively low thermal conductivity of porous pure garnet-phase fluorescent ceramics, they are unable to withstand high-power laser excitation and thermal shock. Furthermore, due to their poor mechanical strength, porous pure garnet-phase fluorescent ceramics are prone to internal microcracks and crack propagation during cutting and polishing, further limiting their application under high-power density light sources. Summary of the Invention

[0004] The embodiments of the present application provide a fluorescent ceramic, a preparation method thereof, and a light source device to at least partially improve the above-mentioned technical problems.

[0005] In a first aspect, an embodiment of the present application provides a fluorescent ceramic comprising a fluorescent phase, a toughened ceramic phase, and pores, wherein the fluorescent phase comprises a plurality of fluorescent particles, the toughened ceramic phase comprises a plurality of zirconia-toughened alumina particles, the fluorescent particles are dispersed in the toughened ceramic phase, and at least part of the pores are dispersed at the junction of the zirconia-toughened alumina particles and at least one of the fluorescent particles.

[0006] In one embodiment, in the fluorescent ceramic, the volume proportion of the toughening ceramic phase is 10%-70%.

[0007] In one embodiment, the volume proportion of zirconium oxide in the toughening ceramic phase is 5% to 30%.

[0008] In one embodiment, the particle size of the zirconium oxide is 1 μm to 20 μm.

[0009] In one embodiment, the fluorescent phase has the general formula:

[0010] Lu 3-x-y Re y (Al 1-z D z )5O 12 :xCe 3+

[0011] Re is one of yttrium, gadolinium, terbium, lutetium, and calcium; D is one of gallium, scandium, silicon, and germanium; 0.0005≤x≤0.05, 0≤y≤1.5, and 0≤z≤0.5.

[0012] In one embodiment, in the fluorescent ceramic, the volume proportion of the fluorescent phase is 20%-80%.

[0013] In one embodiment, the particle size of the fluorescent phase is 0.5 μm to 30 μm.

[0014] In the second aspect, an embodiment of the present application provides a method for preparing fluorescent ceramics, including preparing alumina powder and zirconia powder, mixing and calcining to obtain zirconia-toughened alumina particle powder, preparing fluorescent particle powder, mixing the fluorescent particle powder with zirconia-toughened alumina particle powder, calcining to form composite fluorescent ceramic powder, forming the composite fluorescent ceramic powder, and sintering to form fluorescent ceramics.

[0015] In a third aspect, an embodiment of the present application provides a light source device, comprising a light source and a fluorescent ceramic as described in the first aspect above, wherein the light source emits excitation light, the fluorescent ceramic is located in the optical path of the excitation light, and the fluorescent ceramic is used to convert the excitation light into stimulated light.

[0016] In one embodiment, the wavelength range of the excitation light is 440 nm-470 nm, and the wavelength range of the stimulation light is 495 nm-510 nm.

[0017] The fluorescent ceramics provided by the present application, as well as their preparation methods and light source devices, have a toughened ceramic phase mixed in the fluorescent phase. The toughened ceramic phase has properties such as high thermal conductivity and mechanical reinforcement. On the one hand, it further improves the thermal conductivity of the fluorescent ceramic module to meet the requirements of efficient fluorescence conversion under high power density. On the other hand, it can increase the light scattering of the excitation light and improve the light extraction efficiency of the fluorescent ceramic. In addition, pores are formed in the fluorescent ceramic, and the porous structure can increase the light scattering of the excitation light, further improving the light extraction efficiency of the fluorescent ceramic. The toughened ceramic phase can also effectively improve the mechanical properties of the porous structure of the fluorescent ceramic, obtain better fracture toughness, and have higher reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A schematic structural diagram of a light source device proposed in an embodiment of the present application;

[0020] Figure 2 A schematic diagram of the structure of a fluorescent ceramic proposed in an embodiment of the present application;

[0021] Figure 3 This is a schematic flow chart of a method for preparing fluorescent ceramics proposed in an embodiment of the present application.

[0022] Reference numerals: light source device 1 , fluorescent ceramic 10 , fluorescent phase 11 , toughened ceramic phase 12 , pores 13 , light source 20 . DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0024] In this application, unless otherwise expressly specified or limited, terms such as "mounted," "connected," and "fixed" should be interpreted broadly. For example, these terms may refer to fixed, removable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; internal communication between two components; surface contact only; or surface contact through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0025] In addition, the terms "first", "second", etc. are only used to distinguish descriptions and should not be understood as specific or special structures. The descriptions of the terms "some embodiments", "other embodiments", etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this application, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this application and the features of the different embodiments or examples, unless they are contradictory.

[0026] The present application embodiment provides a light source device 1, see Figure 1 The light source device 1 can be applied to a projection system, a lighting system, etc. The specific setting method and application scenario of the light source device 1 are not limited here.

[0027] The light source device 1 may include a fluorescent ceramic 10 and a light source 20. The light source 20 may be a laser light source or a fluorescent light source. The light source 20 emits excitation light (such as Figure 1 The excitation light can be ultraviolet light, visible light or near infrared light of different wavelengths, and this embodiment is not limited thereto. The fluorescent ceramic 10 is located in the optical path of the excitation light, and the fluorescent ceramic 10 can be used to convert the excitation light into stimulated light (such as Figure 1 When the excitation light emitted by the light source 20 strikes the fluorescent ceramic 10, the fluorescent ceramic 10 absorbs the excitation light and converts it into stimulated light. For example, the fluorescent ceramic 10 can be used to convert blue light. When blue light strikes the fluorescent ceramic 10, the fluorescent ceramic 10 absorbs the blue light energy and converts it into yellow, red, or green light energy, thereby achieving light output of a specific color.

[0028] Furthermore, the shape and size of the fluorescent ceramic 10 can be designed according to specific practical needs and are not limited here. For example, the fluorescent ceramic 10 can be made into different shapes such as round, square, or strip, and the thickness of the fluorescent ceramic 10 can be adjusted to suit a specific scene or light source 20.

[0029] See also Figure 2 The fluorescent ceramic 10 may include a fluorescent phase 11, a toughening ceramic phase 12, and pores 13. The fluorescent phase 11 includes a plurality of fluorescent particles, and the toughening ceramic phase 12 includes a plurality of zirconia-toughened alumina particles. The fluorescent particles are dispersed in the toughening ceramic phase 12, that is, the fluorescent particles may also be distributed between the plurality of zirconia-toughened alumina particles. At least a portion of the pores 13 are dispersed at the junction of the zirconia-toughened alumina particles and at least one of the fluorescent particles, that is, the pores may be distributed between at least two zirconia-toughened alumina particles, between at least two fluorescent particles, or between the zirconia-toughened alumina particles and the fluorescent particles.

[0030] In a more specific embodiment, the general formula of the fluorescent phase 11 is:

[0031] Lu 3-x-y Re y (Al 1-z D z )5O 12 :xCe 3+

[0032] Wherein, Re is one of yttrium, gadolinium, terbium, lutetium, and calcium, D is one of gallium, scandium, silicon, and germanium, 0.0005≤x≤0.05, 0≤y≤1.5, and 0≤z≤0.5. Furthermore, by regulating the various components of the fluorescent phase 11 and their ratios, parameters such as the luminescence peak position and half-maximum width of the spectrum of the converted light of the fluorescent phase 11 can be adjusted so that the converted light can meet subsequent usage requirements. As an example, when the wavelength range of the excitation light is 440nm-470nm, the wavelength range of the converted light of the fluorescent phase 11 can be 495nm-510nm, and the wavelength range of the converted light is within the cyan light band. The wavelength range can be further adjusted by adjusting the type and content of each component according to actual needs.

[0033] For example, the fluorescent phase 11 may be Lu 2.5 Y 0.495 (Al 0.9 Ga 0.1 )5O 12 :0.005Ce 3+ or Lu 2.995 (Al 0.9 Ga 0.1 )5O 12 :0.005Ce 3+ or Lu 2.5 Y 0.497 (Al 0.9 Sc 0.1 )5O 12 :0.003Ce 3+ or Lu 2.5 Y 0.497 (Al 0.9 Sc 0.1 )5O 12 :0.003Ce 3+ or Lu 2.697 Ca 0.3 (Al 0.94 Si 0.06 )5O 12 :0.003Ce 3+ The design and selection of the fluorescent phase 11 can be carried out according to specific implementation requirements and implementation scenarios, and this embodiment does not limit this.

[0034] Since the strength of the porous fluorescent ceramic is reduced, it is not conducive to subsequent processing, and its thermal conductivity will also be affected. In this embodiment, the zirconia toughened alumina particles of the toughened ceramic phase 12 are mixed in the fluorescent phase 11. The fluorescent ceramic 10 can effectively improve the mechanical properties of the porous ceramic by the zirconia toughened alumina particles, obtain better fracture toughness, and have higher reliability. The fluorescent ceramic 10 using zirconia toughened alumina particles can also have high thermal conductivity, meeting the requirements of efficient fluorescence conversion under high power density. Among them, the zirconia toughened alumina particles are a composite material composed of aluminum oxide and zirconium oxide, which has characteristics such as high thermal conductivity and high mechanical strength.

[0035] In one embodiment, the volume fraction of zirconium oxide in the toughening ceramic phase 12 is 5%-30%. Further examples include 6%, 8%, 10%, 15%, 20%, 25%, 28%, and so on. The volume fraction of zirconium oxide cannot be too small, as this will not improve the mechanical properties of the toughening ceramic phase 12, such as fracture toughness. Furthermore, because zirconium oxide has lower thermal conductivity than aluminum oxide, its volume fraction cannot be too large. Excessive zirconium oxide volume fraction in the toughening ceramic phase 12 will reduce the thermal conductivity of the fluorescent ceramic 10, hindering the efficient fluorescence conversion of the fluorescent ceramic 10 at high power density.

[0036] Preferably, the particle size of the zirconium oxide in the toughening ceramic phase 12 can be preferably 1 μm-20 μm, and further examples can be 2 μm, 3 μm, 5 μm, 10 μm, 12 μm, 15 μm, 18 μm, etc. The particle size of the zirconium oxide cannot be too large, as zirconium oxide particles with too large a particle size are not conducive to improving the mechanical properties of the toughening ceramic phase 12, such as fracture toughness.

[0037] In one embodiment, in the fluorescent ceramic 10, the volume proportion of the fluorescent phase 11 can be 20%-80%, and further examples can be 25%, 30%, 40%, 50%, 60%, 70%, 75%, etc. The volume proportion of the toughening ceramic phase 12 is 10%-70%, and further examples can be 15%, 20%, 30%, 40%, 50%, 60%, 65%, etc. When the volume proportion of the fluorescent phase 11 in the fluorescent ceramic 10 is too high, the corresponding volume proportion of the toughening ceramic phase 12 is reduced, which may cause the thermal conductivity and mechanical properties of the fluorescent ceramic 10 to decrease, so that the power range of the excitation light that the fluorescent ceramic 10 can withstand is reduced. When the volume proportion of the toughening ceramic phase 12 in the fluorescent ceramic 10 is too high, the corresponding volume proportion of the fluorescent phase 11 is reduced, and the fluorescence conversion rate of the fluorescent ceramic 10 may be affected. An appropriate amount of the fluorescent phase 11 and the toughening ceramic phase 12 can reduce the impact on the fluorescence conversion rate of the fluorescent ceramic 10 , while ensuring that the thermal conductivity and mechanical properties of the fluorescent ceramic 10 are significantly improved.

[0038] Moreover, during the co-sintering process of the toughened ceramic phase 12 and the fluorescent phase 11, they are not fully densified, and pores 13 are formed in or between the toughened ceramic phase 12 and the fluorescent phase 11. The porous structure can also increase the scattering of the excitation light, further improving the light extraction efficiency of the fluorescent ceramic. The toughened ceramic phase 12 can also effectively improve the mechanical properties of the porous structure fluorescent ceramic 10, obtain better fracture toughness and higher reliability. In another embodiment, pore-forming agents such as starch can be added to the toughened ceramic phase 12 and the fluorescent phase 11 to generate pores 13 in the fluorescent ceramic 10, thereby forming a porous structure fluorescent ceramic 10.

[0039] In one embodiment, the volume proportion of the pores 13 in the fluorescent ceramic 10 is 2%-10%, and further examples include 3%, 4%, 5%, 6%, 7%, 8%, 9%, etc. This can prevent the pores 13 from having an excessively large volume proportion that affects the mechanical properties of the fluorescent ceramic 10, and can also prevent the pores 13 from having an excessively small volume proportion that reduces the light extraction efficiency of the fluorescent ceramic 10. Furthermore, the pores 13 have an aperture size of 0.1 μm-3 μm, and further examples include 0.2 μm, 0.3 μm, 0.5 μm, 0.8 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, etc. Pores 13 of appropriate aperture size can ensure the mechanical properties and light extraction efficiency of the fluorescent ceramic 10.

[0040] The fluorescent ceramic 10 and light source device 1 provided in the embodiment of the present application have a toughening ceramic phase 12 mixed in the fluorescent phase 11, which can improve the mechanical properties such as thermal conductivity and fracture toughness of the fluorescent ceramic 10 module, so that it can meet the requirements of efficient fluorescence conversion under high power density.

[0041] In one embodiment, the fluorescent ceramic 10 can be prepared as follows: Figure 3 As shown, including:

[0042] Step S210: preparing alumina powder and zirconia powder, mixing and calcining them to obtain zirconia-toughened alumina particle powder.

[0043] Prepare alumina powder and zirconia powder. Weigh the alumina powder and zirconia powder according to the appropriate ratio and mix them together to form a mixed powder. To improve sintering, prepare an appropriate amount of sintering aids and dispersants. Place the mixed powders with the alumina and zirconia powders in a ball mill and mix them using a planetary ball mill. The sintering aid can be selected from magnesium fluoride, calcium fluoride, magnesium oxide, calcium carbonate, lithium fluoride, lanthanum trioxide, silicon dioxide, tetraethoxysilane, etc. The dispersant can be selected from at least one of triethanolamine, terpineol, and tributyl phosphate. The ball milling speed can be 200-300 rpm and the duration can be 10-12 hours. The ball-milled powder is dried, then ground and sieved. The mixture is then calcined at 600-700°C to obtain a zirconia-toughened alumina particle powder.

[0044] As you can understand, this embodiment utilizes a method of first creating a zirconium-toughened alumina particle powder from alumina and zirconium oxide powders, and then mixing this powder with the subsequent phosphor particle powder to produce the fluorescent ceramic. Compared to directly mixing and sintering the alumina, zirconium oxide, and phosphor particles, this method can inhibit excessive growth of the zirconium oxide grains, thereby improving the mechanical properties of the fluorescent ceramic, such as fracture toughness.

[0045] Step S220: preparing fluorescent particle powder, mixing the fluorescent particle powder with zirconium oxide toughened alumina particle powder, and calcining to form composite fluorescent ceramic powder.

[0046] Provide fluorescent powder, for example, according to the general formula of fluorescent phase: Lu 3-x-y Re y (Al 1-z D z )5O 12 :xCe 3+The molar fractions of each component, including but not limited to Lu2O3, Al2O3, CeO2, etc., are dissolved in nitric acid, hydrochloric acid or a mixture of the two to form a mixed solution, and the mixed solution is heated in a water bath at a temperature of 60°C-90°C and continuously stirred until each component is completely dissolved. One or more of ammonia water, ammonium bicarbonate and urea are selected as alkaline precipitants, and deionized water is added to the alkaline precipitant to prepare a precipitant solution. The mixed solution is slowly added dropwise to a container containing the precipitant solution, and mechanical stirring, magnetic stirring or ultrasonic vibration is used to oscillate the container during the addition process so that the different substances in the addition process react fully. After the precipitation is complete, it is allowed to stand for 30min-60min, and then the precipitate is filtered, washed, dried, ground and sieved to obtain a precursor powder of the fluorescent phase. The precursor powder of the fluorescent phase is calcined in air or oxygen, and the calcination temperature can be 700°C-1200°C to obtain a powder of the fluorescent phase of the garnet phase, that is, a fluorescent particle powder.

[0047] The powder of the toughening ceramic phase and the powder of the fluorescent phase are weighed in the required proportion, and an appropriate amount of sintering aid and adhesive are prepared. The powder of the toughening ceramic phase and the powder of the fluorescent phase are placed in a mixer and stirred thoroughly. During the mixing process, a small amount of sintering aid and adhesive is gradually added to promote the uniform distribution of the powder and the subsequent sintering process. Among them, the sintering aid can be selected from one of magnesium fluoride, calcium fluoride, magnesium oxide, calcium carbonate, lithium fluoride, lanthanum trioxide, silicon dioxide, tetraethoxysilane, etc., and the mass proportion of the sintering aid in the powder is less than 1%. The adhesive can be polyvinyl butyral ester, etc., and the mass proportion of the adhesive in the powder is less than 1%.

[0048] The mixed powder is sieved through 100-120 mesh, preferably 120 mesh, to ensure that there are no larger particles or impurities in the powder. After sieving, the powder is collected for later use.

[0049] The sieved powder is placed in a high-temperature furnace for calcination. The calcination temperature range is 700°C-1000°C, and the calcination time is 2h-3h. During the calcination process, ensure that the powder is fully heated and does not sinter poorly.

[0050] The calcined powder is screened twice to remove any particulate impurities that may be produced and ensure the purity and uniformity of the powder. After the second screening, composite fluorescent ceramic powder is obtained.

[0051] Step S230: After forming the composite fluorescent ceramic powder, sintering it to form fluorescent ceramics.

[0052] The composite fluorescent ceramic powder is formed by dry pressing or static pressing, using a pressure of 10 MPa to 250 MPa to produce a semi-finished fluorescent ceramic product. The specific pressure value depends on factors such as the particle size of the composite fluorescent ceramic powder and the forming method, and is not limited in this embodiment. The semi-finished fluorescent ceramic product is then pre-sintered in air to remove residual organic components. The pre-sintering temperature and time are determined based on the specific type and performance requirements of the fluorescent ceramic.

[0053] The pre-sintered fluorescent ceramic semi-finished product is placed in a vacuum or protective atmosphere for pressureless sintering, hot pressing sintering, or spark plasma sintering. The fluorescent ceramic semi-finished product is placed in a vacuum furnace or a protective atmosphere furnace. More specifically, the protective atmosphere furnace can use different atmospheres, such as nitrogen, argon, etc., and sintering is performed under pressureless, hot pressing, or spark plasma conditions.

[0054] During the sintering process, the furnace temperature gradually increases, reaching a maximum sintering temperature of 1500°C-1700°C, with a sintering hold time of 2-10 hours. The various components of the fluorescent ceramic semi-finished product react and gradually fuse, resulting in a multi-phase, non-dense fluorescent ceramic block. During the co-sintering process, the toughening ceramic phase and the fluorescent phase are not fully densified, resulting in pores forming within or between the toughening ceramic and fluorescent phases.

[0055] The fluorescent ceramic block is annealed in air at a temperature of 1000-1300°C for 10-100 hours to eliminate the internal stress generated during the sintering process and improve the stability of the fluorescent ceramic. The fluorescent ceramic in this embodiment can also be ground, polished, cut, and other processes.

[0056] The solution of this application is described in more detail below with reference to specific embodiments.

[0057] Example 1

[0058] This embodiment provides a fluorescent ceramic. The general formula of the fluorescent phase of this embodiment can be Lu 2.5 Y 0.495 (Al 0.9 Ga 0.1 )5O 12 :0.005Ce 3+ The general formula of the toughening ceramic phase can be 20% ZrO2-80% Al2O3 ceramic phase.

[0059] The fluorescent ceramics are prepared as follows:

[0060] Zirconia and alumina are weighed in a volume ratio of 1:4 to obtain the raw materials of the toughened ceramics, and the corresponding proportions of magnesium oxide and triethanolamine are calculated according to the raw materials of the toughened ceramics. The raw materials of the toughened ceramics, magnesium oxide, and triethanolamine are put into a ball mill together and planetary ball milled for mixing at a speed of 200 n / min for 11 hours. After drying, grinding, and sieving, the mixture is calcined at 600°C to obtain the toughened ceramic powder.

[0061] According to the general formula of the fluorescent phase: Lu 2.5 Y 0.495 (Al 0.9 Ga 0.1 )5O 12 :0.005Ce 3+ The ratio includes but is not limited to the molar fractions of Lu2O3, Y2O3, Ga2O3, Al2O3, and CeO2, and each component is dissolved in nitric acid to form a mixed solution, and the mixed solution is heated in a water bath at 60°C and continuously stirred until each component is completely dissolved. Ammonia water is selected as an alkaline precipitant, and deionized water is added to the alkaline precipitant to form a precipitant solution. The mixed solution is slowly added dropwise to a container containing the precipitant solution, and the container is mechanically stirred during the addition process so that different substances in the addition process react fully. After the precipitation is complete, it is allowed to stand for 30 minutes, and then the precipitate is filtered, washed, dried, ground, and sieved to obtain a precursor powder of the fluorescent phase. The precursor powder of the fluorescent phase is calcined in air, and the calcination temperature can be 800°C to obtain a powder of the fluorescent phase of the garnet phase.

[0062] Weigh the toughening ceramic phase powder and the fluorescent phase powder in a volume ratio of 3:7. Prepare appropriate amounts of magnesium fluoride and polyvinyl butyral. For example, the weight percentage of magnesium fluoride in the powder should be 0.5%, and the weight percentage of polyvinyl butyral should be 0.3%. Place the toughening ceramic phase powder and the fluorescent phase powder into a mixer and mix thoroughly. During the mixing process, gradually add magnesium fluoride and polyvinyl butyral to promote uniform distribution of the powder and facilitate subsequent sintering.

[0063] The mixed powder is sieved through a 120-mesh sieve to ensure that there are no larger particles or impurities in the powder. After sieving, the powder is collected for later use.

[0064] The sieved powder is placed in a high-temperature furnace for calcination. The calcination temperature range is 700°C and the calcination time is 2 hours. During the calcination process, ensure that the powder is fully heated and does not sinter poorly.

[0065] The calcined powder is screened twice to remove any particulate impurities that may be produced and ensure the purity and uniformity of the powder. After the second screening, composite fluorescent ceramic powder is obtained.

[0066] The composite fluorescent ceramic powder is formed by dry pressing, with a pressure value of 10 MPa to obtain a fluorescent ceramic semi-finished product, and then pre-sintered in air to remove residual organic components in the fluorescent ceramic semi-finished product.

[0067] The pre-sintered fluorescent ceramic semi-finished product is placed in a vacuum for pressureless sintering, resulting in the finished fluorescent ceramic. During the sintering process, the furnace temperature gradually increases, reaching a maximum temperature of 1500°C, and the sintering is held for 10 hours. The various components in the fluorescent ceramic semi-finished product react and gradually fuse, resulting in a multi-phase, non-dense fluorescent ceramic block. The fluorescent ceramic block is then annealed in air at 1000°C for 10 hours to eliminate internal stresses generated during the sintering process and improve the stability of the fluorescent ceramic.

[0068] Example 2

[0069] This embodiment provides a fluorescent ceramic. The general formula of the fluorescent phase of this embodiment can be Lu 2.995 (Al 0.9 Ga 0.1 )5O 12 :0.005Ce 3+ The general formula of the toughening ceramic phase can be 15% ZrO2-85% Al2O3 ceramic phase.

[0070] The fluorescent ceramics are prepared as follows:

[0071] Zirconia and alumina are weighed in a volume ratio of 3:17 to obtain the raw materials of the toughened ceramics, and the corresponding ratios of tetraethoxysilane and alanine are calculated according to the raw materials of the toughened ceramics. The raw materials of the toughened ceramics, tetraethoxysilane and alanine are put into a ball mill together and planetary ball milled for mixing at a speed of 300n / min for 13 hours. After drying, grinding and sieving, the powder is calcined at 700°C to obtain the toughened ceramic powder.

[0072] According to the general formula of the fluorescent phase: Lu 2.995 (Al 0.9 Ga 0.1 )5O 12 :0.005Ce 3+The ratio includes but is not limited to the molar fractions of Lu2O3, Ga2O3, Al2O3, and CeO2, and each component is dissolved in hydrochloric acid to form a mixed solution, and the mixed solution is heated in a water bath at a heating temperature of 90°C and continuously stirred until each component is completely dissolved. Ammonium bicarbonate is selected as an alkaline precipitant, and deionized water is added to the alkaline precipitant to prepare a precipitant solution. The mixed solution is slowly added dropwise to a container containing the precipitant solution, and the container is magnetically stirred during the addition process so that different substances in the addition process react fully. After the precipitation is complete, it is allowed to stand for 60 minutes, and then the precipitate is filtered, washed, dried, ground, and sieved to obtain a precursor powder of the fluorescent phase. The precursor powder of the fluorescent phase is calcined in air, and the calcination temperature can be 700°C to obtain a powder of the fluorescent phase of the garnet phase.

[0073] Weigh the toughening ceramic phase powder and the fluorescent phase powder in a volume ratio of 2:8. Prepare appropriate amounts of lithium fluoride and polyvinyl butyral. For example, the weight percentage of lithium fluoride in the powder should be 0.7%, and the weight percentage of polyvinyl butyral should be 0.9%. Place the toughening ceramic phase powder and the fluorescent phase powder into a mixer and mix thoroughly. During the mixing process, gradually add lithium fluoride and polyvinyl butyral to promote uniform distribution of the powder and facilitate subsequent sintering.

[0074] Sieve the mixed powder through a 100-mesh sieve to ensure that there are no larger particles or impurities in the powder. After sieving, collect the powder for later use.

[0075] The sieved powder is placed in a high-temperature furnace for calcination. The calcination temperature range is 1000°C and the calcination time is 3 hours. During the calcination process, ensure that the powder is fully heated and does not sinter poorly.

[0076] The calcined powder is screened twice to remove any particulate impurities that may be produced and ensure the purity and uniformity of the powder. After the second screening, composite fluorescent ceramic powder is obtained.

[0077] The composite fluorescent ceramic powder is formed by static pressing, and a pressure value of 250 MPa is used to obtain a fluorescent ceramic semi-finished product, which is then pre-sintered in air to remove residual organic components in the fluorescent ceramic semi-finished product.

[0078] The pre-sintered fluorescent ceramic semi-finished product is placed in a nitrogen atmosphere for pressureless sintering to form the finished fluorescent ceramic. During the sintering process, the furnace temperature gradually increases, reaching a maximum sintering temperature of 1700°C, and the sintering temperature is maintained for 2 hours. The various components in the fluorescent ceramic semi-finished product react and gradually fuse, forming a multi-phase, non-dense fluorescent ceramic block. The fluorescent ceramic block is then annealed in air at a temperature of 1300°C for 100 hours to eliminate internal stress generated during the sintering process and improve the stability of the fluorescent ceramic.

[0079] Example 3

[0080] This embodiment provides a fluorescent ceramic. The general formula of the fluorescent phase of this embodiment can be Lu 2.5 Y 0.497 (Al 0.9 Sc 0.1 )5O 12 :0.003Ce 3+ The general formula of the toughening ceramic phase can be 10% ZrO2-90% Al2O3 ceramic phase.

[0081] The fluorescent ceramics are prepared as follows:

[0082] Zirconia and alumina are weighed in a volume ratio of 1:9 to obtain the raw materials of the toughened ceramics, and the corresponding ratios of calcium carbonate and alanine are calculated based on the raw materials of the toughened ceramics. The raw materials of the toughened ceramics, calcium carbonate, and alanine are put into a ball mill together and planetary ball milled for mixing at a speed of 250n / min for 12 hours. After drying, grinding, and sieving, the mixture is calcined at 650°C to obtain the toughened ceramic powder.

[0083] According to the general formula of the fluorescent phase: Lu 2.5 Y 0.497 (Al 0.9 Sc 0.1 )5O 12 :0.003Ce 3+The ratio includes but is not limited to the molar fractions of Lu2O3, Y2O3, Al2O3, Sc2O3, and CeO2, and each component is dissolved in a mixture of nitric acid and hydrochloric acid to form a mixed solution, and the mixed solution is heated in a water bath at 80°C and stirred continuously until each component is completely dissolved. Urea is selected as an alkaline precipitant, and deionized water is added to the alkaline precipitant to form a precipitant solution. The mixed solution is slowly added dropwise to a container containing the precipitant solution, and ultrasonic vibration is used to vibrate the container during the addition process so that different substances in the addition process react fully. After the precipitation is complete, it is allowed to stand for 50 minutes, and then the precipitate is filtered, washed, dried, ground, and sieved to obtain a precursor powder of the fluorescent phase. The precursor powder of the fluorescent phase is calcined in air, and the calcination temperature can be 1000°C to obtain a powder of the fluorescent phase of the garnet phase.

[0084] Weigh the toughening ceramic phase powder and the fluorescent phase powder in a volume ratio of 3:7. Prepare appropriate amounts of lanthanum trioxide and polyvinyl butyral. For example, the lanthanum trioxide and polyvinyl butyral content of the powder should be 0.1% by weight and 0.1% by weight, respectively. Place the toughening ceramic phase powder and the fluorescent phase powder into a mixer and mix thoroughly. During mixing, gradually add lanthanum trioxide and polyvinyl butyral to promote uniform distribution of the powders and facilitate subsequent sintering.

[0085] The mixed powder is sieved through a 120-mesh sieve to ensure that there are no larger particles or impurities in the powder. After sieving, the powder is collected for later use.

[0086] The sieved powder is placed in a high-temperature furnace for calcination. The calcination temperature range is 800°C and the calcination time is 2.5 hours. During the calcination process, ensure that the powder is fully heated and does not sinter poorly.

[0087] The calcined powder is screened twice to remove any particulate impurities that may be produced and ensure the purity and uniformity of the powder. After the second screening, composite fluorescent ceramic powder is obtained.

[0088] The composite fluorescent ceramic powder is formed by dry pressing, and a pressure value of 100 MPa is used to obtain a fluorescent ceramic semi-finished product, which is then pre-sintered in air to remove residual organic components in the fluorescent ceramic semi-finished product.

[0089] The pre-sintered fluorescent ceramic semi-finished product is placed in an argon protective atmosphere and hot-pressed to form the finished fluorescent ceramic. During the sintering process, the furnace temperature gradually increases, reaching a maximum sintering temperature of 1600°C, and the sintering temperature is maintained for 5 hours. The various components in the fluorescent ceramic semi-finished product react and gradually fuse, forming a multi-phase, non-dense fluorescent ceramic block. The fluorescent ceramic block is then annealed in air at a temperature of 1500°C for 50 hours to eliminate internal stress generated during the sintering process and improve the stability of the fluorescent ceramic.

[0090] Example 4

[0091] This embodiment provides a fluorescent ceramic. The general formula of the fluorescent phase of this embodiment can be Lu 2.697 Ca 0.3 (Al 0.94 Si 0.06 )5O 12 :0.003Ce 3+ The general formula of the toughening ceramic phase can be 5% ZrO2-95% Al2O3 ceramic phase.

[0092] The fluorescent ceramics are prepared as follows:

[0093] Zirconia and alumina are weighed in a volume ratio of 1:19 to obtain the raw materials of the toughened ceramics, and the corresponding ratios of silica and alanine are calculated based on the raw materials of the toughened ceramics. The raw materials of the toughened ceramics, silica, and alanine are put into a ball mill together and planetary ball milled for mixing at a speed of 200 n / min for 11 hours. After drying, grinding, and sieving, the mixture is calcined at 600°C to obtain the toughened ceramic powder.

[0094] According to the general formula of the fluorescent phase: Lu 2.697 Ca 0.3 (Al 0.94 Si 0.06 )5O 12 :0.003Ce 3+The ratio includes but is not limited to the molar fractions of Lu2O3, CaO2, Al2O3, SiO2, and CeO2, and each component is dissolved in nitric acid to form a mixed solution, and the mixed solution is heated in a water bath at 60°C and continuously stirred until each component is completely dissolved. A mixture of ammonia, ammonium bicarbonate and urea is selected as an alkaline precipitant, and deionized water is added to the alkaline precipitant to form a precipitant solution. The mixed solution is slowly added dropwise to a container containing the precipitant solution, and the container is mechanically stirred during the addition process so that different substances in the addition process react fully. After the precipitation is complete, the precipitate is allowed to stand for 30 minutes, and then the precipitate is filtered, washed, dried, ground, and sieved to obtain a precursor powder of the fluorescent phase. The precursor powder of the fluorescent phase is calcined in air, and the calcination temperature can be 800°C to obtain a powder of the fluorescent phase of the garnet phase.

[0095] Weigh the toughening ceramic phase powder and the fluorescent phase powder in a volume ratio of 2:8. Prepare appropriate amounts of tetraethoxysilane and polyvinyl butyral. For example, the weight percentage of tetraethoxysilane in the powder should be 0.5%, and the weight percentage of polyvinyl butyral should be 0.5%. Place the toughening ceramic phase powder and the fluorescent phase powder into a mixer and mix thoroughly. During the mixing process, gradually add tetraethoxysilane and polyvinyl butyral to promote uniform distribution of the powder and facilitate subsequent sintering.

[0096] The mixed powder is sieved through a 120-mesh sieve to ensure that there are no larger particles or impurities in the powder. After sieving, the powder is collected for later use.

[0097] The sieved powder is placed in a high-temperature furnace for calcination. The calcination temperature range is 700°C and the calcination time is 2 hours. During the calcination process, ensure that the powder is fully heated and does not sinter poorly.

[0098] The calcined powder is screened twice to remove any particulate impurities that may be produced and ensure the purity and uniformity of the powder. After the second screening, composite fluorescent ceramic powder is obtained.

[0099] The composite fluorescent ceramic powder is formed by dry pressing, with a pressure value of 10 MPa to obtain a fluorescent ceramic semi-finished product, and then pre-sintered in air to remove residual organic components in the fluorescent ceramic semi-finished product.

[0100] The pre-sintered fluorescent ceramic semi-finished product is placed in a vacuum for spark ion sintering to form the finished fluorescent ceramic. During the sintering process, the furnace temperature gradually increases, reaching a maximum sintering temperature of 1500°C, and the sintering temperature is maintained for 10 hours. The various components in the fluorescent ceramic semi-finished product react and gradually fuse, forming a multi-phase, non-dense fluorescent ceramic block. The fluorescent ceramic block is then annealed in air at a temperature of 1000°C for 10 hours to eliminate internal stress generated during the sintering process and improve the stability of the fluorescent ceramic.

[0101] Comparative Example 1

[0102] This embodiment provides a pure phase fluorescent ceramic, the general formula of which is Lu 2.5 Y 0.495 (Al 0.9 Ga 0.1 )5O 12 :0.005Ce 3+ .

[0103] The above-mentioned pure phase fluorescent ceramic is prepared in the following manner:

[0104] According to Lu 2.5 Y 0.495 (Al 0.9 Ga 0.1 )5O 12 :0.005Ce 3+ Lu2O3 powder, Y2O3 powder, Ga2O3 powder, Al2O3 powder, and CeO2 powder are mixed in stoichiometric proportions. Each powder is dissolved in nitric acid to form a mixed solution, which is then heated in a water bath at 60°C and stirred continuously until all components are completely dissolved. An ammonia-water mixture is selected as an alkaline precipitant, and deionized water is added to the alkaline precipitant to form a precipitant solution. The mixed solution is slowly added dropwise to a container containing the precipitant solution, and the container is mechanically stirred during the addition process to allow the different substances to react fully during the addition process. After precipitation is complete, the mixture is allowed to stand for 30 minutes, and then the precipitate is filtered, washed, dried, ground, and sieved to obtain a precursor powder. The precursor powder is calcined in air at a temperature of 800°C to obtain a pure-phase fluorescent ceramic powder.

[0105] The powder of the pure phase fluorescent ceramic is sieved for the second time.

[0106] The powder of the pure phase fluorescent ceramic is formed by dry pressing, and a pressure value of 10 MPa is used to obtain a semi-finished product of the pure phase fluorescent ceramic. The semi-finished product is then pre-sintered in air to remove residual organic components in the semi-finished product of the pure phase fluorescent ceramic.

[0107] The pre-sintered pure-phase fluorescent ceramic semi-finished product is placed in a vacuum for pressureless sintering to form the finished pure-phase fluorescent ceramic product. Specifically, during the sintering process, the temperature in the furnace gradually increases, with the maximum sintering temperature being 1500°C, and the sintering is held at this temperature for 10 hours. The various components in the pure-phase fluorescent ceramic semi-finished product react and gradually fuse to form a pure-phase fluorescent ceramic block. The pure-phase fluorescent ceramic block is annealed in air at a temperature of 1000°C for 10 hours to eliminate the internal stress generated during the sintering process and improve the stability of the fluorescent ceramic.

[0108] Comparative Example 2

[0109] This embodiment provides a dual-phase fluorescent ceramic, the general formula of which is Lu 2.5 Y 0.495 (Al 0.9 Ga 0.1 )5O 12 :0.005Ce 3+ -Al2O3.

[0110] The above-mentioned dual-phase fluorescent ceramic is prepared in the following manner:

[0111] According to Lu 2.5 Y 0.495 (Al 0.9 Ga 0.1 )5O 12 :0.005Ce 3+ Lu2O3 powder, Y2O3 powder, Ga2O3 powder, Al2O3 powder, and CeO2 powder are mixed in stoichiometric proportions. Each powder is dissolved in nitric acid to form a mixed solution, which is then heated in a water bath at 60°C and stirred continuously until all components are completely dissolved. A mixture of ammonia and water is selected as an alkaline precipitant, and deionized water is added to the alkaline precipitant to form a precipitant solution. The mixed solution is slowly added dropwise to a container containing the precipitant solution, and the container is mechanically stirred during the addition process to allow the different substances to react fully during the addition process. After precipitation is complete, the mixture is allowed to stand for 30 minutes, and then the precipitate is filtered, washed, dried, ground, and sieved to obtain a fluorescent phase precursor powder. The fluorescent phase precursor powder is calcined in air at a calcination temperature of 800°C to obtain a fluorescent phase powder.

[0112] Weigh the Al2O3 particles and phosphor powder in a volume ratio of 2:8. Prepare appropriate amounts of tetraethoxysilane and polyvinyl butyral. For example, the weight ratio of tetraethoxysilane to the powder should be 0.5%, and the weight ratio of polyvinyl butyral to the powder should be 0.5%. Place the Al2O3 particles and phosphor powder in a mixer and mix thoroughly. During mixing, gradually add tetraethoxysilane and polyvinyl butyral to ensure a more even distribution of the powder and facilitate subsequent sintering.

[0113] The mixed powder is sieved through a 120-mesh sieve to ensure that there are no larger particles or impurities in the powder. After sieving, the powder is collected for later use.

[0114] The sieved powder is placed in a high-temperature furnace for calcination at a temperature of 700°C and a calcination time of 2 hours.

[0115] The calcined powder is sieved twice to obtain powder of dual-phase fluorescent ceramic.

[0116] The powder of the dual-phase fluorescent ceramic is formed by dry pressing, and a pressure value of 10 MPa is used to obtain a semi-finished product of the dual-phase fluorescent ceramic. The semi-finished product is then pre-sintered in air to remove residual organic components in the semi-finished product of the dual-phase fluorescent ceramic.

[0117] The pre-sintered dual-phase fluorescent ceramic semi-finished product is placed in a vacuum for pressureless sintering, resulting in the finished dual-phase fluorescent ceramic. During the sintering process, the furnace temperature gradually increases, reaching a maximum sintering temperature of 1500°C, with a sintering hold time of 10 hours. The components of the dual-phase fluorescent ceramic semi-finished product react and gradually fuse, forming a dual-phase fluorescent ceramic block. The dual-phase fluorescent ceramic block is then annealed in air at 1000°C for 10 hours to eliminate internal stresses generated during sintering and improve its stability.

[0118] The relationship between the thermal conductivity and fracture toughness of the fluorescent ceramic of Example 1 of the present application and Comparative Examples 1 and 2 is shown in Table 1:

[0119] Table 1 Comparison of fluorescent ceramic parameters of Example 1 and Comparative Examples 1 and 2

[0120]

[0121] As can be seen from Table 1, compared with the fluorescent ceramics with a pure phase structure in Comparative Example 1 and a two-phase structure in Comparative Example 2, the fluorescent ceramic containing a toughened ceramic phase in Example 1 of the present application has higher thermal conductivity and fracture toughness. This is because the use of a toughened ceramic phase in the porous fluorescent ceramic in Example 1 of the present application can effectively improve the mechanical properties of the porous ceramic, obtain better fracture toughness, and have higher reliability. Compared with Al2O3 in Comparative Example 2, the ZrO2-toughened Al2O3 in Example 1 can reduce the sintering temperature of the fluorescent ceramic to aid sintering, thereby reducing the content of pores in the fluorescent ceramic and reducing the size of the pores, which is beneficial to improving the density of the fluorescent ceramic and obtaining higher thermal conductivity. In addition, the increase in thermal conductivity can increase the thermal stability of the luminescence of the fluorescent phase, thereby obtaining a higher excitation light power density threshold, and can show higher reliability under high-power density laser excitation, meeting the requirements of efficient fluorescence conversion under high power density.

[0122] The fluorescent ceramics provided in this embodiment, as well as their preparation methods and light source devices, have a toughened ceramic phase mixed in the fluorescent phase. The toughened ceramic phase has properties such as high thermal conductivity and mechanical reinforcement, which further improves the thermal conductivity of the fluorescent ceramic module to meet the requirements of efficient fluorescence conversion under high power density. It can also increase the light scattering of the excitation light and improve the light extraction efficiency of the fluorescent ceramic. In addition, pores are formed in the fluorescent ceramic, and the porous structure can also increase the light scattering of the excitation light, further improving the light extraction efficiency of the fluorescent ceramic. The toughened ceramic phase can also effectively improve the mechanical properties of the porous structure of the fluorescent ceramic, obtain better fracture toughness, and have higher reliability.

[0123] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A fluorescent ceramic, characterized in that: include: a fluorescent phase comprising a plurality of fluorescent particles; as well as A toughened ceramic phase, the toughened ceramic phase comprising a plurality of zirconia toughened alumina ceramic particles, the fluorescent particles being dispersed in the toughened ceramic phase; Pores, at least part of which are dispersed at the junction of the zirconia-toughened alumina particles and at least one of the fluorescent particles.

2. The fluorescent ceramic according to claim 1, characterized in that In the fluorescent ceramic, the volume proportion of the toughening ceramic phase is 10%-70%.

3. The fluorescent ceramic according to claim 1, characterized in that: In the toughening ceramic phase, the volume proportion of zirconium oxide is 5%-30%.

4. The fluorescent ceramic according to claim 1, characterized in that The particle size of the zirconium oxide is 1 μm-20 μm.

5. The fluorescent ceramic according to claim 1, characterized in that The general formula of the fluorescent phase is: Lu 3-x-y Re y (Al 1-z D z )5O 12 :xCe 3+ Re is one of yttrium, gadolinium, terbium, lutetium, and calcium; D is one of gallium, scandium, silicon, and germanium; 0.0005≤x≤0.05, 0≤y≤1.5, and 0≤z≤0.

5.

6. The fluorescent ceramic according to claim 1, characterized in that: In the fluorescent ceramic, the volume proportion of the fluorescent phase is 20%-80%.

7. The fluorescent ceramic according to claim 1, characterized in that: The particle size of the fluorescent phase is 0.5 μm-30 μm.

8. A method for preparing fluorescent ceramics, characterized in that: include: Alumina powder and zirconia powder are prepared, mixed and calcined to obtain zirconia-toughened alumina particle powder; Fluorescent particle powder is prepared, the fluorescent particle powder is mixed with the zirconium oxide toughened alumina particle powder, and the mixture is calcined to form a composite fluorescent ceramic powder. After the composite fluorescent ceramic powder is formed, the composite fluorescent ceramic powder is sintered to form a fluorescent ceramic.

9. A light source device, characterized in that: include: a light source, the light source emitting excitation light; as well as The fluorescent ceramic according to any one of claims 1 to 7, wherein the fluorescent ceramic is located in the optical path of the excitation light, and the fluorescent ceramic is used to convert the excitation light into converted light.

10. The light source device according to claim 9, wherein The wavelength range of the excitation light is 440nm-470nm, and the wavelength range of the conversion light is 495nm-510nm.

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