CN108059446A - A kind of white fluorescence ceramics and preparation method thereof - Google Patents

Abstract

The present invention provides a white light fluorescent ceramic and a preparation method thereof. The white light fluorescent ceramic belongs to the CaO‑ _SiO2 ‑ _{B2O3 ‑ MnO} ‑ _{Ce2O3 ‑ Tb2O3} system, wherein the preparation of a white light fluorescent ceramic The method comprises the following steps: (1) weighing the raw materials into a ball mill and mixing them uniformly, putting them into a high-temperature furnace, and calcining for 8 to 12 hours under a reducing atmosphere condition of 1250° C. to 1350° C. to obtain a powder; (2) Mix the powder and the premixed solution, and place them in a ball mill for ball milling for 2 to 8 hours to obtain a mixed slurry; (3) Add ammonium persulfate to the mixed slurry, and after stirring, pour the mixed slurry into a mold for drying After 24 to 48 hours, the green body is obtained; (4) the green body is placed in a high-temperature furnace, and the calcination is continued for 8 to 12 hours under the condition of 1250 ° C to 1350 ° C in an air atmosphere to obtain a ceramic sheet; (5) the ceramic sheet The final ceramic sheet is obtained by grinding; this method is simple to operate, the shape and size of the product can be adjusted, and it can be prepared in batches with a high yield. The prepared white fluorescent ceramics can be widely used in high-power, remote LED, laser light source and other fields.

Description

A kind of white light fluorescent ceramic and its preparation method

technical field

The invention belongs to the technical field of ceramics, and in particular relates to a white light fluorescent powder and a preparation method thereof, and fluorescent ceramics and a preparation method thereof.

Background technique

White light emitting diodes (WLEDs), as a new generation of solid-state lighting devices, have the advantages of energy saving, environmental protection, fast response, small size, etc., and have been widely used in road lighting, flat panel display and other fields. The most mature way for white LEDs to achieve white light emission is the phosphor conversion method, that is, coating phosphors around the LED chip. At present, commercial white LEDs generally use blue LED chips to excite YAG: Ce ³⁺ yellow phosphor combination scheme. However, due to the lack of red light components in the white light obtained by this combination scheme, the color rendering index of the light source is low [1,2]. Another common method is WLEDs prepared by combining ultraviolet LED chips with three-color (red + green + blue) phosphors. In this system, the addition of red light significantly improves the color rendering index, but it also introduces other problems. For example, the strong absorption effect of red and green phosphors on blue light leads to lower luminous efficiency of blue phosphors, and the different decay rates of the three phosphors will cause color difference. In addition, the complexity of the preparation process will increase the cost. These deficiencies cannot be ignored in practical applications. Compared with multi-component white light-emitting phosphors, single-phase white light-emitting phosphors have higher luminous efficiency, excellent color rendering index, better stability and color expression, and are relatively simple in preparation process, so single-phase White light phosphors have become a hot spot in the research of phosphors for WLEDs in recent years.

However, after the single-phase white phosphor is packaged into an LED device, in the process of use, if the absorbed energy cannot be released through the emitted light as soon as possible, the phosphor will release heat through non-radiation, which will make the temperature of the device continue to rise If the temperature is too high, it will lead to aging, cracking and yellowing of the resin and silica gel, and at the same time, the efficiency of the phosphor will be reduced due to heat decay, and finally fall into a vicious circle. Therefore, the research and development of fluorescent materials that can be excited by ultraviolet chips and withstand high-energy excitation and high density is a major problem that needs to be solved urgently in the development of LED technology.

In view of this, the present invention is proposed.

Contents of the invention

Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a white light phosphor and its preparation method, fluorescent ceramics and its preparation method, the preparation process is simple, the cost is low, the solid content is high, the yield is high, and remote packaging is adopted The way, the heat dissipation effect of the light source is good, the reliability of the light source is improved, the application range is wide, and it is suitable for the mass production of the factory model.

In order to achieve the above object, the present invention provides a white light fluorescent ceramic and a preparation method thereof. The white light fluorescent ceramic belongs to the CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ system.

Preferably, a preparation method of white light fluorescent ceramics comprises the following steps:

(1) Preparation of white light phosphor: Weigh the proportion of the components (based on the mass of the oxidation standard): 0%≤CaO+SrO+BaO≤77.92%, 0%<SiO ₂ ≤69.99%, 0%<B ₂ O ₃ ≤13.69%, 0%<CeO ₂ ≤17.72%, 0%<MnO≤4.04%, and 0%<Tb ₂ O ₃ ≤7.93% are put into the ball mill for 2-8 hours and mixed evenly, then put In a high-temperature furnace, calcining for 8 to 12 hours under reducing atmosphere conditions of 1250°C to 1350°C (reduction and sintering of the white phosphor powder are carried out simultaneously, that is, the temperature of the reducing atmosphere is equal to the temperature of the sintering atmosphere) to obtain the white phosphor powder;

(2) Gel injection molding: mix the white light phosphor with a mass ratio of 1000:173 and the premix, the ratio of each component of the premix is (by mass percentage), 0%<H ₂ O<88.3 %, 0%<N,N dimethylacrylamide<59.1%, 0%<N,N'-methylenebisacrylamide<3.1%, 0%<ammonium polyacrylate<30.7%, 0%<polyethylene Glycol < 7.1%, and placed in a roller ball mill for 24 to 48 hours to make a mixed slurry;

(3) Add initiator ammonium persulfate to the mixed slurry, the amount of the initiator added accounts for the mass percent of the premixed liquid, 0% < ammonium persulfate < 2.3%, after stirring, pour the mixed slurry into Dry in the mold for 24 to 48 hours to obtain a green body;

(4) Put the green body into a high-temperature furnace, and continue calcining for 8 to 12 hours under a reducing atmosphere at 1250°C-1350°C to obtain a ceramic sheet;

(5) Grinding the ceramic sheet to obtain the final ceramic sheet.

Preferably, the catalyst N,N,N,N-tetramethylethylenediamine is added to the slurry 30 minutes before the end of the ball milling in step (2).

Preferably, the amount of the catalyst added in the mass percentage of the premix liquid is 0%<N,N,N,N-tetramethylethylenediamine<0.37%.

Provided by the present invention has the following beneficial effects:

1. Using the gel injection molding process to ceramicize the white light phosphor, it has higher luminous efficiency, excellent color rendering index, better stability and color expression, and at the same time the preparation process is simple, the cost is low, and the solid content is high , high yield, suitable for large-scale and mass production of industrial models, and suitable for wide application and promotion.

2. The present invention uses remote fluorescent powder to separate the ceramic and the chip from the fluorescent powder, which is beneficial to the heat dissipation of the light source, thereby improving the reliability of the light source, and can withstand high-density and high-energy excitation. Heat, high temperature of the device leads to aging of resin and silica gel, etc., and the vicious cycle of reducing the efficiency of phosphor due to heat decay, which can be used in high-power lighting devices, such as laser light sources and high-power remote LED light sources.

Description of drawings

FIG. 1 is an emission spectrum of a white phosphor powder of a white phosphor ceramic provided by the present invention with an excitation wavelength of 338 nm.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments and accompanying drawings, so as to help understand the content of the present invention.

Example 1:

A white light fluorescent ceramic and a preparation method thereof provided by the present invention, the white light fluorescent ceramic belongs to the CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ system;

Wherein, a preparation method of white light fluorescent ceramics comprises the following steps:

1. White light phosphor preparation: according to the group of CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ =59.78:24.91:7.22:4.04:1.96:2.09 (based on oxide content) Proportionally, accurately weigh the medicine with a total mass of 100g, including 68.86g of CaCO ₃ , 16.03g of SiO ₂ , 8.25g of H ₃ BO ₃ , 4.22g of MnCO ₃ , 1.26g of CeO ₂ , and 1.37g of Tb ₄ O ₇ . After ball milling in a ball mill for 4 hours, transfer to a muffle furnace at 1250° C. for 8 hours, and cool to room temperature to obtain a white phosphor.

2. Gel injection molding: In terms of mass ratio, white light phosphor: premix: initiator: catalyst = 1000: 173: 4: 0.64, 100 g of white phosphor and 17.3 g of premix (wherein each component in the premix They are: 13g of deionized water, 2.52g of N,N dimethylacrylamide, 0.15g of N,N'-methylene bisacrylamide, 1.32g of ammonium polyacrylate, and 0.31g of polyethylene glycol) and mixed them for the first time in Add 60g of white light fluorescent powder to the premixed solution, add 20g in two times after ball milling for 24 hours, and add 0.064g of catalyst N,N,N,N-tetramethylethylenediamine to the slurry 30 minutes before the end of ball milling.

3. Pour the slurry after ball milling into a beaker, add 0.4g initiator ammonium persulfate to it, and stir gently, pass the slurry through an 80-mesh stainless steel screen to filter the air bubbles in the slurry, and then quickly dissolve the slurry Pour it into a pre-prepared mold, then let it stand for about 10 hours, then dry it in an oven at 50°C for 4 hours, demold it, and continue to dry it for 12 hours.

4. Put the dried green body in a muffle furnace and calcinate it under a reducing atmosphere at 1250°C for 12 hours. After cooling and taking it out, the CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ system is obtained. Remote white light fluorescent ceramic.

5. Polish the fluorescent ceramic sheet to obtain the final remote white light fluorescent ceramic.

The present invention uses the fluorescence spectrometer of model F-7000 to test the spectral properties of the fluorescent ceramics of this system, as shown in Figure 1, the fluorescent ceramics of this system emits white light whose excellent coordinates are located at (.0.289,0.250) under the excitation of 338nm light, Among them, the red light band is located at 623nm-750nm, the central wavelength is located at 673nm, the green light band is located at 479nm-623nm, the central wavelength is located at 544nm, the blue light band is located at 350nm-479nm, and the central wavelength is located at 398nm.

Example 2:

A white light fluorescent ceramic and a preparation method thereof provided by the present invention, the white light fluorescent ceramic belongs to the CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ system;

Wherein, a preparation method of white light fluorescent ceramics comprises the following steps:

1. White light phosphor preparation: according to the group of CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ =58.43:24.48:7.09:3.97:1.93:4.10 (based on oxide content) Proportionally, accurately weigh the drug with a total mass of 100g, including CaCO ₃ 67.87g, SiO ₂ 15.85g, H ₃ BO ₃ 8.15, MnCO ₃ 4.17g, CeO ₂ 1.25g, Tb ₄ O ₇ 2.71g, and put them in a ball mill After ball milling for 2 hours, transfer to a muffle furnace at 1250° C. for 8 hours, and cool to room temperature to obtain a white phosphor.

2. Gel injection molding: In terms of mass ratio, white light phosphor: premix: initiator: catalyst = 1000: 173: 4: 0.64, 100 g of white phosphor and 17.3 g of premix (wherein each component in the premix They are: 7.82g of deionized water, 5.33g of N,N dimethylacrylamide, 0.47g of N,N'-methylene bisacrylamide, 2.87g of ammonium polyacrylate, and 0.81g of polyethylene glycol). Add 60g of white light fluorescent powder to the premixed liquid, add 20g in two times after ball milling for 26 hours, and add 0.064g of catalyst N,N,N,N-tetramethylethylenediamine to the slurry 30 minutes before the end of ball milling .

3. Pour the slurry after ball milling into a beaker, add 0.4g initiator ammonium persulfate to it, and stir gently, pass the slurry through an 80-mesh stainless steel screen to filter the air bubbles in the slurry, and then quickly dissolve the slurry Pour it into a pre-prepared mold, then let it stand for about 10 hours, then dry it in an oven at 50°C for 4 hours, demold it, and continue to dry it for 12 hours.

4. Put the dried green body in a muffle furnace for calcination in a reducing atmosphere at 1250°C for 8 hours, and after cooling and taking it out, the CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ system is obtained. Remote white light fluorescent ceramic.

5. Polish the fluorescent ceramic sheet to obtain the final remote white light fluorescent ceramic.

The present invention uses the fluorescence spectrometer of model F-7000 to test the spectral properties of the fluorescent ceramics of this system, as shown in Figure 1, the fluorescent ceramics of this system emits the white light whose excellent coordinates are located at (0.288,0.278) under the excitation of 338nm light, wherein , the red light band is located at 623nm-750nm, the central wavelength is at 673nm, the green light band is located at 479nm-623nm, the central wavelength is at 544nm, the blue light band is located at 350nm-479nm, and the central wavelength is at 399nm.

Example 3: A white light fluorescent ceramic and its preparation method provided by the present invention, a white light fluorescent ceramic belongs to the CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ system;

Wherein, a preparation method of white light fluorescent ceramics comprises the following steps:

1. White light phosphor preparation: according to the group of CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ =57.12:24.06:6.97:3.90:1.90:6.04 (based on oxide content) Proportionally, accurately weigh the medicine with a total mass of 100g, including 66.90g of CaCO ₃ , 15.66g of SiO ₂ , 8.06g of H ₃ BO ₃ , 4.12g of MnCO ₃ , 1.24g of CeO ₂ , and 4.02g of Tb ₄ O ₇ . After ball milling in a ball mill for 6 hours, transfer to a muffle furnace at 1250° C. for 10 hours, and cool to room temperature to obtain a white phosphor.

2. Gel injection molding: In terms of mass ratio, white light phosphor: premix: initiator: catalyst = 1000: 173: 4: 0.64, 100 g of white phosphor and 17.3 g of premix (wherein each component in the premix They are: deionized water 15.22g, N,N dimethylacrylamide 0.21g, N,N'-methylene bisacrylamide 0.52g, ammonium polyacrylate 0.14g, polyethylene glycol 1.21g) mixing, first Add 60g of white light fluorescent powder to the premixed liquid, add 20g in two times after ball milling for 36 hours, and add 0.064g of catalyst N,N,N,N-tetramethylethylenediamine to the slurry 30 minutes before the end of ball milling .

3. Pour the slurry after ball milling into a beaker, add 0.4g initiator ammonium persulfate to it, and stir gently, pass the slurry through an 80-mesh stainless steel screen to filter the air bubbles in the slurry, and then quickly dissolve the slurry Pour it into a pre-prepared mold, then let it stand for about 10 hours, then dry it in an oven at 50°C for 4 hours, demold it, and continue to dry it for 12 hours.

4. Put the dried green body in a muffle furnace and calcinate it under a reducing atmosphere at 1250°C for 10 hours. After cooling and taking it out, the CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ system is obtained. Remote white light fluorescent ceramic.

5. Polish the fluorescent ceramic sheet to obtain the final remote white light fluorescent ceramic.

The present invention uses the fluorescence spectrometer of model F-7000 to test the spectral properties of the system fluorescent ceramics, as shown in Figure 1, the system fluorescent ceramics emits white light with excellent coordinates at (0.303,0.309) under the excitation of 338nm light, wherein , the red light band is located at 623nm-750nm, the center wavelength is at 673nm, the green light band is located at 477nm-623nm, the center wavelength is at 544nm, the blue light band is at 350nm-477nm, and the center wavelength is at 397nm.

Example 4: A white light fluorescent ceramic and its preparation method provided by the present invention, a white light fluorescent ceramic belongs to the CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ system;

Wherein, a preparation method of white light fluorescent ceramics comprises the following steps:

1. Preparation of white light phosphor: according to the group of CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ =55.86:23.66:6.85:3.84:1.86:7.93 (based on oxide content) Proportionally, accurately weigh the medicine with a total mass of 100g, including 65.96g of CaCO ₃ , 15.48g of SiO ₂ , 7.97g of H ₃ BO ₃ , 4.07g of MnCO ₃ , 1.22g of CeO ₂ , and 5.30g of Tb ₄ O ₇ . After ball milling in a ball mill for 8 hours, transfer to a muffle furnace at 1250° C. for 12 hours, and cool to room temperature to obtain a white phosphor.

2. Gel injection molding: In terms of mass ratio, white light phosphor: premix: initiator: catalyst = 1000: 173: 4: 0.64, 100 g of white phosphor and 17.3 g of premix (wherein each component in the premix They are: deionized water 1.38g, N,N dimethylacrylamide 10.16g, N,N'-methylene bisacrylamide 0.12g, polyacrylic acid ammonium 5.29g, polyethylene glycol 0.35g) mixing, first Add 60g of white light fluorescent powder to the premixed liquid, add 20g in two times after ball milling for 48 hours, and add 0.064g of catalyst N,N,N,N-tetramethylethylenediamine to the slurry 30 minutes before the end of ball milling .

3. Pour the slurry after ball milling into a beaker, add 0.4g initiator ammonium persulfate to it, and stir gently, pass the slurry through an 80-mesh stainless steel screen to filter the air bubbles in the slurry, and then quickly dissolve the slurry Pour it into a pre-prepared mold, then let it stand for about 10 hours, then dry it in an oven at 50°C for 4 hours, demold it, and continue to dry it for 12 hours.

4. Put the dried green body in a muffle furnace and calcinate it under a reducing atmosphere at 1250°C for 12 hours. After cooling and taking it out, the CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ system is obtained. Remote white light fluorescent ceramic.

5. Polish the fluorescent ceramic sheet to obtain the final remote white light fluorescent ceramic.

The present invention uses the fluorescence spectrometer of model F-7000 to test the spectral properties of the fluorescent ceramics of this system, as shown in Figure 1, the fluorescent ceramics of this system emits white light with excellent coordinates at (0.317,0.316) under the excitation of 338nm light, wherein , the red light band is located at 623nm-750nm, the central wavelength is at 673nm, the green light band is located at 478nm-623nm, the central wavelength is at 544nm, the blue light band is located at 350nm-478nm, and the central wavelength is at 397nm.

The invention provides a white light fluorescent ceramic and a preparation method thereof. The fluorescent ceramic can be used in high-power lighting devices, such as laser light sources and high-power remote LED light sources. The remote packaging method is used to separate the phosphor material from the chip, which is conducive to the heat dissipation of the light source, thereby improving the reliability of the light source.

In this paper, specific examples are used to illustrate the inventive concept in detail, and the descriptions of the above embodiments are only used to help understand the core idea of the present invention. It should be pointed out that for those skilled in the art, any obvious modification, equivalent replacement or other improvement should be included in the protection scope of the present invention without departing from the inventive concept.

Claims (4)

1. A white light fluorescent ceramic, characterized in that the white light fluorescent ceramic belongs to the CaO-SiO ₂ -B ₂ O ₃ -MnO-Ce ₂ O ₃ -Tb ₂ O ₃ system. 2. the preparation method of a kind of white light fluorescent ceramics according to claim 1, is characterized in that, comprises the following steps: (1) Preparation of white light phosphor: Weigh the proportion of the components (based on the mass of the oxidation standard): 0%≤CaO+SrO+BaO≤77.92%, 0%<SiO ₂ ≤69.99%, 0%<B ₂ O ₃ ≤13.69%, 0%<CeO ₂ ≤17.72%, 0%<MnO≤4.04%, and 0%<Tb ₂ O ₃ ≤7.93% are put into a ball mill for 2-8 hours and mixed evenly, then put into a high-temperature furnace, and calcined for 8 to 12 hours under a reducing atmosphere at 1250°C to 1350°C to obtain a white phosphor; (2) Gel injection molding: mix the white light phosphor with a mass ratio of 1000:173 and the premix, the ratio of each component of the premix is (by mass percentage), 0%<H ₂ O<88.3 %, 0%<N,N dimethylacrylamide<59.1%, 0%<N,N'-methylenebisacrylamide<3.1%, 0%<ammonium polyacrylate<30.7%, 0%<polyethylene Glycol < 7.1%, and placed in a roller ball mill for 24 to 48 hours to make a mixed slurry; (3) Initiator ammonium persulfate is added to the mixed slurry, the amount of the initiator added accounts for the mass percentage of the premixed solution, 0% < ammonium persulfate < 2.3%, after stirring, the mixed slurry is poured into the mold Medium drying for 24 to 48 hours to obtain a green body; (4) Put the green body into a high-temperature furnace, and continue calcining for 8 to 12 hours under a reducing atmosphere at 1250°C-1350°C to obtain a ceramic sheet; (5) Grinding the ceramic sheet to obtain the final ceramic sheet. 3. the preparation method of a kind of fluorescent ceramics according to claim 1 is characterized in that, 30min before described step (2) ball milling ends, add catalyst N,N,N,N-tetramethylethane diamine. 4. A method for preparing fluorescent ceramics according to claim 1, characterized in that the amount of catalyst added in the mass percent of the premixed solution is 0%<N,N,N,N-tetramethylethylenediamine <0.37%.