Yellow fluorescent ceramic as well as preparation method and application thereof

Abstract

The invention discloses yellow fluorescent ceramic as well as a preparation method and application thereof, and belongs to the technical field of fluorescent ceramic material preparation. According to the yellow fluorescent ceramic disclosed by the invention, continuous adjustment of the color temperature of a light source is realized by finely regulating and controlling the luminous ion concentration in the YAG: Ce fluorescent ceramic and the thickness of the ceramic, unprecedented flexibility and adaptability are given to LED illumination, and the requirements of flexible regulation and control of the color temperature and higher luminous quality in diversified application scenes can be met; the material can be used as a key material of a color converter, and has a wide application prospect in the field of high-power LED illumination.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorescent ceramic material preparation, and in particular relates to a yellow fluorescent ceramic and a preparation method and application thereof. Background Art

[0002] LED lighting has been widely used in home lighting, industrial lighting, projection display and other fields due to its advantages such as high efficiency, environmental protection and energy saving, long life, rich colors and dimmability. White light sources are mainly composed of blue LED chips plus yellow, green and red fluorescent conversion materials. Therefore, fluorescent conversion materials are the core of white light sources and determine the key performance of white light such as color quality, brightness and efficiency. Since different scenes have different requirements for the color quality of white light sources, higher requirements are placed on the color rendering performance of fluorescent materials.

[0003] At present, the yellow fluorescent material used in white light illumination is mainly Y 3 Al 5 O 12 :Ce (YAG:Ce), its forms include phosphor, fluorescent glass film, fluorescent crystal and fluorescent ceramic. Among them, fluorescent ceramic has good anti-laser radiation performance and high efficiency, which is the focus of current research. The high-temperature solid phase method is the most commonly used method to prepare YAG:Ce fluorescent ceramics. For example, Li Jiang and others from the Shanghai Institute of Ceramics, Chinese Academy of Sciences, used α-Al 2 O 3 , Y 2 O 3 and CeO 2 The powder is used as the raw material, TEOS and MgO are used as sintering aids, and the precursor powder is obtained by ball milling for 12 hours. Then it is pressed into tablets and cold isostatically pressed under a pressure of 250MPa to obtain a blank. The obtained blank is sintered at 1750°C for 20 hours in a vacuum environment and annealed at 1450°C in air for 10 hours to obtain YAG:Ce fluorescent ceramics. Under the excitation of a blue light LED chip, its color coordinates are (0.3319, 0.3827) and the lumen efficiency is 122.4lm / W (Ce:YAGTransparent Ceramics Enabling High Luminous Efficacy for High-power LEDs / LDs[J].Journal of Inorganic Materials,2021,36(8)). Zhang et al. from Chongqing University ball milled the raw powder Y 2 O 3 、Al 2 O 3 、CeO 2The precursor powder was mixed and cold isostatically pressed under a pressure of 200 MPa to obtain a green blank; the green blank was sintered at 1700°C in an oxygen atmosphere for 5 hours, 15 hours, and 45 hours to obtain YAG:Ce ceramics. The density of all samples reached 99.9% of the theoretical density. When the ceramic with an average grain size of about 36 μm was excited by an LED chip with a wavelength of 455 nm and an excitation power of 24.75 W, the luminous flux was 5924.60 lm and the lumen efficiency was 309.81 lm / W (Effect of grain size on the luminescent properties of Ce 3+ doped Y 3 Al 5 O 12 ceramic phosphor plates[J], Ceramics International, 2020, 46, 10452-10456.). Zhu Qiangqiang and others from China University of Metrology added YAG:Ce powder to 2 O 3 and Al 2 O 3 , mixed evenly and sintered to obtain ceramics, sintered at 1650-1750℃ in a nitrogen-hydrogen mixed atmosphere for 3 hours, and then hot isostatically pressed at 1650℃ and 150MPa pressure for 1 hour to obtain a ceramic sample. 2 O 3 and Al 2 O 3 Ceramics can absorb blue light more efficiently than YAG:Ce ceramics and exhibit more uniform luminescence (Transparent YAG:Ce ceramic with designed low light scattering for high-power blue LED and LD applications[J], Journal of the European Ceramic Society, 2021, 41, 735-740.).

[0004] In summary, YAG:Ce fluorescent ceramics show broad application prospects in the field of LED lighting, but current research focuses on how to improve its luminous efficiency, while the demand for flexible control of color temperature and higher luminous quality in diversified application scenarios is still insufficient. Summary of the invention

[0005] The purpose of the present invention is to provide a yellow fluorescent ceramic and a preparation method and application thereof, so as to solve the technical problem that the existing fluorescent ceramics are difficult to meet the requirements for lighting light sources in different scenarios.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The invention discloses a yellow fluorescent ceramic, wherein the chemical formula of the yellow fluorescent ceramic is Y 3-x Ce x Al 5 O 12 ; Among them, 0.001≤x≤0.009;

[0008] The thickness of the yellow fluorescent ceramic is d, 0.3≤d≤0.7 mm.

[0009] The present invention also discloses a method for preparing the yellow fluorescent ceramic, comprising the following steps:

[0010] Follow Y 3-x Ce x Al 5 O 12 Weighing Y source powder, Ce source powder and Al source powder in a stoichiometric ratio to prepare a precursor powder;

[0011] Pressing the precursor powder into tablets to obtain a ceramic green body;

[0012] The ceramic blank is sintered to obtain fluorescent ceramics; the fluorescent ceramics are annealed and then ground and polished to obtain yellow fluorescent ceramics.

[0013] Furthermore, the specific steps of preparing the precursor powder are:

[0014] Follow Y 3-x Ce x Al 5 O 12 Y source powder, Ce source powder and Al source powder were weighed in a stoichiometric ratio, mixed evenly by wet ball milling, and then pre-sintered and sieved in sequence to obtain precursor powder.

[0015] Furthermore, the wet ball milling has a rotation speed of 80-150 rpm / min and a time of 6-12 h.

[0016] Furthermore, the Y source powder is one or a combination of Y oxides or Y salts;

[0017] The Ce source powder is one or a combination of Ce oxides or Ce salts;

[0018] The Al source powder is one or a combination of Al oxides or Al salts.

[0019] Furthermore, the Y source powder is Y 2 O 3 ; The Ce source powder is Ce 2 (CO 3 ) 2 ; The Al source powder is Al 2 O 3 .

[0020] Furthermore, the tableting method is dry pressing combined with cold isostatic pressing.

[0021] Furthermore, the sintering treatment temperature is 1600-1800° C., and the holding time is 5-20 hours.

[0022] Furthermore, the annealing treatment is carried out at a temperature of 1300-1500° C. and a holding time of 2-10 hours.

[0023] The invention also discloses the application of the yellow fluorescent ceramic in the field of LED lighting.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The invention discloses a yellow fluorescent ceramic, the material composition of which is Y 3-x Ce x Al 5 O 12 , the value range of x is 0.001≤x≤0.009, the thickness of the fluorescent ceramic is d, and the value range of d is 0.3≤d≤0.7mm; by finely controlling the concentration of luminescent ions in the YAG:Ce fluorescent ceramic and the thickness of the ceramic itself, by optimizing and adjusting the concentration ratio x of the luminescent ions in the ceramic matrix and the thickness d of the ceramic, the color temperature of the white light source can be continuously adjusted. Since the concentration of the luminescent ions will affect the intensity of the emitted light, the concentration of the luminescent ions of the present invention can adjust the emission ratio of yellow light in the spectrum; the thickness of the ceramic can change the propagation path of the light, and the present invention can be used to adjust the color temperature of the white light source. The thickness of the ceramic is set to enhance the reflection and refraction of the incident blue light, extend the transmission path of the blue light and thus enhance the absorption of the blue light, thereby adjusting the ratio of yellow light to blue light in the spectrum; in addition, the concentration of luminescent ions and the thickness of the ceramic itself can change the transmittance of the ceramic to adjust the proportion of transmitted blue light, thereby achieving continuous adjustment of the color temperature of the light source, giving LED lighting unprecedented flexibility and adaptability, and being able to meet the needs of diversified application scenarios for flexible control of color temperature and higher luminous quality. It can be used as a key material for color converters and has broad application prospects in the field of high-power LED lighting.

[0026] The present invention also discloses a method for preparing the yellow fluorescent ceramic. The method adopts the high-purity raw materials selected by the present invention and the process conditions provided by the present invention, designs the components and structure thereof, and combines the annealing process in air after sintering to obtain a yellow fluorescent ceramic containing Ce. 3+ High-performance fluorescent ceramics with luminescent ions have the advantages of simple process and low production cost.

[0027] The present invention also discloses the application of the yellow fluorescent ceramic in the field of high-power LED lighting. According to relevant experimental results, the fluorescent ceramic of the present invention has continuously adjustable excitation color temperature of the blue light LED chip within the adjustment range of 3000-8000K, which can meet the lighting needs in different scenes. The stimulated emission wavelength can supplement the missing yellow component in the lighting, and has great application potential in the field of high-power LED lighting. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Y prepared in Example 1 of the present invention 2.999 Ce 0.001 Al 5 O 12 (x=0.001, d=0.3mm) XRD pattern of yellow fluorescent ceramic;

[0029] Figure 2 Y prepared in Example 4 of the present invention 2.995 Ce 0.005 Al 5 O 12 (x=0.005,d=0.3mm) Excitation spectrum of yellow fluorescent ceramics (λ em =540nm) and emission spectrum (λ ex =450nm);

[0030] Figure 3 Y prepared in Example 1-Example 5 2.999 Ce 0.001 Al 5 O 12 (x=0.001,d=0.3,0.5,0.7mm), Y 3-x Ce x Al 5 O 12 (x=0.005, 0.007, d=0.3) Transmittance of yellow fluorescent ceramics.

[0031] Figure 4 Y prepared in Example 1, Example 2 and Example 4 2.999 Ce 0.001 Al 5 O 12 (x=0.001, d=0.3), Y 2.999Ce 0.001 Al 5 O 12 (x = 0.001, d = 0.5 mm) and Y 2.995 Ce 0.005 Al 5 O 12 (x=0.005, d=0.3mm) Luminescence spectrum obtained by combining fluorescent ceramics with LED chips;

[0032] Wherein: a-Example 1; b-Example 2; c-Example 3;

[0033] Figure 5 This is a color temperature diagram obtained by combining the yellow fluorescent ceramics prepared in Examples 1 to 5 with an LED chip. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0035] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0036] Herein, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0037] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0038] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0039] The present invention provides a yellow fluorescent ceramic, the material composition is Y 3-x Cex Al 5 O 12 , the value range of x is 0.001≤x≤0.009; the thickness of the yellow fluorescent ceramic is d, 0.3≤d≤0.7mm.

[0040] The present invention also provides a method for preparing the yellow fluorescent ceramic, comprising the following steps:

[0041] Step 1: preparing precursor powder;

[0042] Step 2: Pressing the precursor powder obtained above into a tablet to obtain a ceramic green body;

[0043] Step 3: Sintering the ceramic blank obtained above to obtain fluorescent ceramics;

[0044] Step 4: annealing the fluorescent ceramic obtained above;

[0045] Step 5: Grind the annealed ceramic to different thicknesses and polish it to obtain yellow fluorescent ceramic.

[0046] Preferably, in step 1, the process of preparing the precursor powder is specifically as follows:

[0047] According to the stoichiometric ratio Y 3-x Ce x Al 5 O 12 The Y source powder, Ce source powder and Al source powder were weighed, and the raw material powders were mixed evenly by wet ball milling, and then pre-sintered and sieved to obtain the precursor powder.

[0048] Preferably, the tableting method in step 2 is compression molding combined with cold isostatic pressing or the like.

[0049] Preferably, in step 3, the sintering temperature is 1600-1800° C., and the holding time is 5-20 h.

[0050] Preferably, in step 4, the atmosphere of the annealing treatment is an air atmosphere; the temperature of the annealing treatment is 1300-1500° C., and the annealing time is 2-10 hours.

[0051] More preferably, the temperature of the annealing treatment is 1300°C, 1350°C, 1400°C, 1450°C or 1500°C.

[0052] More preferably, the annealing time is 2 h, 4 h, 8 h or 10 h.

[0053] Preferably, 0.001≤x≤0.009, the upper limit of x is selected from 0.001, 0.003, 0.005, and the lower limit of x is selected from 0.005, 0.007, 0.009.

[0054] Preferably, the Y source powder is one or a combination of Y oxides or salts.

[0055] More preferably, the Y source powder is Y 2 O 3 .

[0056] Preferably, the Al source powder is one or a combination of Al oxides or salts.

[0057] More preferably, the Al source powder is Al 2 O 3 .

[0058] Preferably, the Ce source powder is one or a combination of Ce oxides or salts.

[0059] More preferably, the Ce source powder is Ce 2 (CO 3 ) 2 .

[0060] Preferably, the rotation speed of the wet ball milling is 120-150 rpm / min, and the ball milling time is 6-12 h.

[0061] Preferably, the thickness of the yellow fluorescent ceramic is d, 0.3≤d≤0.7 mm.

[0062] Preferably, the upper limit of d is selected from 0.3, 0.4 or 0.5 mm.

[0063] Preferably, the lower limit of d is selected from 0.5, 0.6 or 0.7 mm.

[0064] The raw material used in the present invention is α-Al with a commercial purity of more than 99.9%. 2 O 3 or γ-Al 2 O 3 , Y 2 O 3 、CeO 2 or Ce 2 (CO 3 ) 2 .

[0065] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0066] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0067] Example 1

[0068] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.999 Ce 0.001 Al 5 O 12 (x=0.001, d=0.3 mm), including the following steps:

[0069] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.999 Ce 0.001 Al 5 O 12 Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 80 rpm / min for 6 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0070] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0071] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1800° C. for 5 hours to obtain a fluorescent ceramic;

[0072] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1400° C. for 4 hours;

[0073] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.3 mm.

[0074] Example 2

[0075] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.999Ce 0.001 Al 5 O 12 (x=0.001, d=0.5mm), including the following steps:

[0076] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.999 Ce 0.001 Al 5 O 12 Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 80 rpm / min for 6 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0077] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0078] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1800° C. for 5 hours to obtain a fluorescent ceramic;

[0079] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1400° C. for 4 hours;

[0080] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.5 mm.

[0081] Example 3

[0082] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.999 Ce 0.001 Al 5 O 12 (x=0.001, d=0.7 mm), including the following steps:

[0083] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.999 Ce 0.001 Al5 O 12 Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 80 rpm / min for 6 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0084] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0085] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1800° C. for 5 hours to obtain a fluorescent ceramic;

[0086] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1400° C. for 4 hours;

[0087] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.7 mm.

[0088] Example 4

[0089] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.995 Ce 0.005 Al 5 O 12 (x=0.005, d=0.3 mm), including the following steps:

[0090] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.999 Ce 0.001 Al 5 O 12 Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 80 rpm / min for 6 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0091] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0092] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1800° C. for 5 hours to obtain a fluorescent ceramic;

[0093] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1400° C. for 4 hours;

[0094] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.3 mm.

[0095] Example 5

[0096] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.993 Ce 0.007 Al 5 O 12 (x=0.009, d=0.3 mm), including the following steps:

[0097] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.993 Ce 0.007 Al 5 O 12 Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 80 rpm / min for 6 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0098] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0099] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1800° C. for 5 hours to obtain a fluorescent ceramic;

[0100] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1400° C. for 4 hours;

[0101] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.3 mm.

[0102] Example 6

[0103] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.995 Ce 0.005 Al 5 O12 (x=0.005, d=0.7 mm), including the following steps:

[0104] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.995 Ce 0.005 Al 5 O 12 Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 80 rpm / min for 6 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0105] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0106] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1800° C. for 5 hours to obtain a fluorescent ceramic;

[0107] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1400° C. for 4 hours;

[0108] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.7 mm.

[0109] Example 7

[0110] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.991 Ce 0.009 Al 5 O 12 (x=0.009, d=0.5 mm), including the following steps:

[0111] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.991 Ce 0.009 Al 5 O 12Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 80 rpm / min for 6 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0112] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0113] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1800° C. for 5 hours to obtain a fluorescent ceramic;

[0114] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1400° C. for 4 hours;

[0115] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.5 mm.

[0116] Example 8

[0117] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.991 Ce 0.009 Al 5 O 12 (x=0.009, d=0.7 mm), including the following steps:

[0118] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.991 Ce 0.009 Al 5 O 12 Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 80 rpm / min for 6 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0119] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0120] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1800° C. for 5 hours to obtain a fluorescent ceramic;

[0121] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1400° C. for 4 hours;

[0122] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.7 mm.

[0123] Example 9

[0124] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.991 Ce 0.009 Al 5 O 12 (x=0.009, d=0.5 mm), including the following steps:

[0125] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.991 Ce 0.009 Al 5 O 12 Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 80 rpm / min for 6 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0126] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0127] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1600° C. for 20 hours to obtain a fluorescent ceramic;

[0128] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1500° C. for 10 h;

[0129] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.5 mm.

[0130] Example 10

[0131] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.991 Ce 0.009 Al 5 O12 (x=0.009, d=0.5 mm), including the following steps:

[0132] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.991 Ce 0.009 Al 5 O 12 Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 150 rpm / min for 12 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0133] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0134] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1900° C. for 5 hours to obtain a fluorescent ceramic;

[0135] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1300° C. for 2 h;

[0136] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.5 mm.

[0137] Embodiment 11

[0138] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.991 Ce 0.009 Al 5 O 12 (x=0.009, d=0.7 mm), including the following steps:

[0139] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.991 Ce 0.009 Al 5 O 12Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 100 rpm / min for 10 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0140] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0141] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1700° C. for 10 hours to obtain a fluorescent ceramic;

[0142] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1500° C. for 2 h;

[0143] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.7 mm.

[0144] Example 12

[0145] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.993 Ce 0.007 Al 5 O 12 (x=0.009, d=0.3 mm), including the following steps:

[0146] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.993 Ce 0.007 Al 5 O 12 Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 80 rpm / min for 6 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0147] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0148] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1800° C. for 5 hours to obtain a fluorescent ceramic;

[0149] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1350° C. for 6 hours;

[0150] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.3 mm.

[0151] Embodiment 13

[0152] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.993 Ce 0.007 Al 5 O 12 (x=0.009, d=0.3 mm), including the following steps:

[0153] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.993 Ce 0.007 Al 5 O 12 Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 80 rpm / min for 6 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0154] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0155] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1750° C. for 8 hours to obtain a fluorescent ceramic;

[0156] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1350° C. for 6 hours;

[0157] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.7 mm.

[0158] Embodiment 14

[0159] A method for preparing a yellow fluorescent ceramic. In this embodiment, the chemical formula of the yellow fluorescent ceramic is Y 2.993 Ce 0.007 Al 5 O12 (x=0.009, d=0.3 mm), including the following steps:

[0160] Step 1: Commercially available Y with a purity of 99.99% 2 O 3 、α-Al 2 O 3 、Ce 2 (CO 3 ) 2 Raw material powder according to the stoichiometric ratio Y 2.993 Ce 0.007 Al 5 O 12 Weigh, use anhydrous ethanol as a ball milling medium, wet-mill in a planetary ball mill at a ball milling speed of 80 rpm / min for 6 h to mix evenly, and then pre-sinter and sieve in sequence to obtain a precursor powder;

[0161] Step 2: The precursor powder obtained above is pressed into tablets by combining compression molding with cold isostatic pressing to obtain a ceramic green body;

[0162] Step 3: placing the ceramic blank in a vacuum furnace for sintering at a temperature of 1750° C. for 8 hours to obtain a fluorescent ceramic;

[0163] Step 4: annealing the fluorescent ceramic obtained above in an air atmosphere at a temperature of 1450° C. for 8 hours;

[0164] Step 5: The annealed ceramic is thinned and polished to obtain a yellow fluorescent ceramic sheet with a diameter of 15 mm and a thickness of 0.6 mm.

[0165] The yellow fluorescent ceramics prepared in Examples 1 to 5 were tested for their performance:

[0166] The phase structure test was carried out using the D8 Advance fully automatic X-ray diffractometer from Bruker AXS, Germany. The test conditions were copper target K ɑ Rays (wavelength ), scanning voltage 40k V, scanning current 40m A, scanning step length 0.02°, scanning angle range 10-90°, scanning speed 10° / min. Excitation and emission spectra were obtained by testing the F4600 spectrometer produced by Hitachi, Japan, with a xenon lamp as the excitation light source. Transmittance was obtained by testing the Lambda950 UV-Vis-Infrared spectrophotometer produced by PerkinElmer, USA. LED performance was obtained by testing the SPIC-300 spectral color illuminance meter produced by Everfine.

[0167] Figure 1Y prepared in Example 1 2.999 Ce 0.001 Al 5 O 12 (x=0.001, d=0.3mm) XRD pattern of yellow fluorescent ceramics shows that the prepared ceramics are single YAG cubic phase, and the luminescent ion Ce 3+ Can be better integrated into the lattice.

[0168] Figure 2 Y prepared in Example 4 2.995 Ce 0.005 Al 5 O 12 (x=0.005,d=0.3mm) Excitation spectrum of yellow fluorescent ceramics (λ em =540nm) and emission spectrum (λ ex =450nm), the horizontal axis is the wavelength. The vertical axis is the luminous intensity. The best excitation peak is near 450nm, which is a good match with the commercial blue light LED chip. The emission peak of the obtained ceramic is near 540nm.

[0169] Figure 3 Y prepared in Example 1-Example 5 2.999 Ce 0.001 Al 5 O 12 (x=0.001, d=0.3, 0.5, 0.7mm), Y 3-x Ce x Al 5 O 12 (x=0.005、0.009,d=0.3) Transmittance of yellow fluorescent ceramics. When x=0.001, d=0.3mm, the transmittance is 51%, when x=0.001, d=0.5mm, the transmittance is 42%, when x=0.009, d=0.3mm, the transmittance is 47%. Higher transmittance is the basis for combining fluorescent ceramics with LED chips.

[0170] Figure 4 Y prepared according to Example 1, Example 2 and Example 4 2.999 Ce 0.001 Al 5 O 12 (x=0.001, d=0.3), Y 2.999 Ce 0.001 Al 5 O 12 (x = 0.001, d = 0.5 mm) and Y 2.995 Ce 0.005 Al 5 O 12(x=0.005, d=0.3mm) The luminescence spectrum obtained by combining yellow fluorescent ceramics with LED chips. The horizontal axis is the wavelength, and the vertical axis is the normalized luminescence intensity. The luminescence peak at a wavelength of 450nm is the luminescence of the blue light LED chip, and the luminescence in the range of 475-760nm is the luminescence of the prepared fluorescent ceramics under the excitation of the LED chip, and the luminescence range is in the yellow light region. As the luminescent ion concentration x increases and the ceramic thickness d increases, the proportion of yellow light in the spectrum gradually increases.

[0171] Figure 5 The correlated color temperature obtained by combining the yellow fluorescent ceramics prepared in Examples 1 to 5 with the LED chip, the horizontal axis is the example, and the vertical axis is the color temperature. The correlated color temperature of Example 1 is 10000K, the correlated color temperature of Example 2 is 8732K, and the correlated color temperature of Example 5 is 5112K. The color temperature can be continuously adjusted by adjusting the concentration x of the luminescent ions in the fluorescent ceramic and the thickness d of the ceramic to meet the needs of different lighting scenes.

[0172] The present invention provides complete preparation steps from raw material preparation to final product, including preparation of precursor powder, tableting, sintering, annealing and grinding and polishing, etc. The detailed description of these steps helps to ensure the repeatability of the preparation process and the consistency of product quality; the rotation speed and time of wet ball milling are precisely controlled to ensure uniform mixing and refinement of the raw materials; this helps to improve the density and luminescence performance of the ceramic; at the same time, a variety of possible Y source powders, Ce source powders and Al source powders are provided for selection, which increases the flexibility in the preparation process and allows the raw material type to be adjusted according to specific needs; since a dry pressing method combined with cold isostatic pressing and appropriate sintering and annealing temperatures are selected, these all help to obtain high-quality ceramic products; since the yellow fluorescent ceramic has a precise chemical composition, optimized thickness and a sophisticated preparation process, it is expected to exhibit excellent luminescence performance, thermal stability and mechanical strength, thereby meeting the demand for high-performance fluorescent materials in the field of LED lighting.

[0173] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A yellow fluorescent ceramic, characterized in that: The chemical formula of the yellow fluorescent ceramic is Y 3-x Ce x Al5O 12 ; Among them, 0.001≤x≤0.009; The thickness of the yellow fluorescent ceramic is d, 0.3≤d≤0.7 mm.

2. The method for preparing a yellow fluorescent ceramic according to claim 1, characterized in that: The following steps are involved: Follow Y 3-x Ce x Al5O 12 Weighing Y source powder, Ce source powder and Al source powder in a stoichiometric ratio to prepare a precursor powder; Pressing the precursor powder into tablets to obtain a ceramic green body; The ceramic blank is sintered to obtain fluorescent ceramics; the fluorescent ceramics are annealed and then ground and polished to obtain yellow fluorescent ceramics.

3. The method for preparing a yellow fluorescent ceramic according to claim 2, characterized in that: The specific steps of preparing the precursor powder are: Follow Y 3-x Ce x Al5O 12 Y source powder, Ce source powder and Al source powder were weighed in a stoichiometric ratio, mixed evenly by wet ball milling, and then pre-sintered and sieved in sequence to obtain precursor powder.

4. The method for preparing a yellow fluorescent ceramic according to claim 3, characterized in that: The wet ball milling has a rotation speed of 80-150 rpm / min and a time of 6-12 h.

5. The method for preparing a yellow fluorescent ceramic according to claim 2, characterized in that: The Y source powder is one or a combination of Y oxides or Y salts; The Ce source powder is one or a combination of Ce oxides or Ce salts; The Al source powder is one or a combination of Al oxides or Al salts.

6. The method for preparing a yellow fluorescent ceramic according to claim 2, characterized in that: The Y source powder is Y2O3; the Ce source powder is Ce2(CO3)2; and the Al source powder is Al2O3.

7. The method for preparing a yellow fluorescent ceramic according to claim 2, characterized in that: The tableting method is dry pressing combined with cold isostatic pressing.

8. The method for preparing a yellow fluorescent ceramic according to claim 2, characterized in that: The sintering treatment temperature is 1600-1800° C., and the heat preservation time is 5-20 hours.

9. The method for preparing a yellow fluorescent ceramic according to claim 2, characterized in that: The annealing treatment is carried out at a temperature of 1300-1500° C. and a heat preservation time of 2-10 hours.

10. Application of the yellow fluorescent ceramic according to claim 1 in the field of LED lighting.

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