CN106630604A - Low-melting-point tellurate glass ceramic, preparation method and application of low-melting-point tellurate glass ceramic - Google Patents

Abstract

The invention discloses a low melting point tellurate glass ceramic, a preparation method and an application thereof. The present invention is composed of glass raw material and YAG fluorescent powder; wherein: the glass raw material is composed of the following molar percentage components: 50-70mol% TeO ₂ , 10-30mol% Na ₂ O, 5-25mol% ZnO , the sum of the mole fractions of each component is 100%; the mass of the fluorescent powder is 6-10% of the total mass of the glass raw material. The glass ceramic preparation process of the present invention has the advantages of simple operation, low melting temperature, short production cycle, no toxic substances produced, easy large-scale production and the like. The prepared glass ceramics are used in LED devices after mechanical processing.

Description

A kind of low melting point tellurate glass ceramics, preparation method and application thereof

technical field

The invention relates to the technical field of inorganic non-metallic materials, in particular to a low melting point tellurate glass ceramic, a preparation method and an application thereof.

Background technique

White LEDs have attracted widespread attention due to their advantages of energy saving, no pollution, high color rendering, long life, and fast response. Its working principle is that through the combination of blue light InGaN chip and yellow phosphor powder, the blue light emitted by the InGaN chip is partially absorbed by the phosphor powder, making it excited to emit yellow light, and the unabsorbed blue light is mixed with the yellow light emitted by the phosphor powder to obtain white light. At present, the packaging material of LED is mainly made by mixing silica gel, resin and phosphor in a certain proportion. The white light obtained by this packaging method, due to the heat source of the packaging material chip, the heat emitted by the chip and the short-wave radiation will accelerate the aging of the packaging material. Yellow leads to a decrease in transmittance and shortens the service life of white LEDs. Therefore, people hope to replace the fluorescent resin for packaging by preparing YAG:Ce single crystal, YAG:Ce glass ceramics, and YAG:Ce ceramics, so as to solve the problems of difficult heat dissipation and easy aging. However, the preparation of YAG:Ce single crystal doped with rare earth ions has problems such as long single crystal production cycle, strict raw material requirements, too complicated process, high production cost, and difficulty in forming large-scale products. The preparation of YAG:Ce ceramics is more difficult than the preparation of YAG:Ce single crystals. It requires high melting temperature and strict control of atmosphere to eliminate pores from powder to melting. The preparation of YAG:Ce glass ceramics has the advantages of relatively low glass melting temperature, short production cycle, and low production cost. It can overcome the difficulties in the preparation of single crystal and transparent ceramics. In addition, compared with powder, it has better thermal stability and light Small attenuation, wide range of color temperature adjustment, and more uniform luminescence, it is expected to replace powder.

The refractive index of YAG phosphor particles is high (n=1.84), and the refractive index of epoxy resin/silica gel is low (n≈1.5). Their mixing together will lead to severe light scattering loss and low light extraction efficiency. Scholars and experts at home and abroad have done a lot of work to solve the problems of LED. In order to develop phosphors with excellent luminous performance: they modified the synthesis process of phosphors, improved the stability of phosphors by post-treatment methods, and coated the surface of phosphors with chemical methods to make phosphors The physical and chemical stability of the phosphor is better; the substrate of the phosphor is replaced, such as glass, glass-ceramics, ceramics, etc., and the coating process of the phosphor is improved; With excellent thermal stability, it can effectively fill the shortage of LED packaging.

Although the literature and patents on the method of preparing low-melting point YAG:Ce fluorescent glass have been publicly reported, there are generally two main problems in summary: first, the preparation process of the glass is relatively complicated, and requires two steps of melting-cooling process to complete. The process consumes a lot of energy. Second, the design of the material composition is unreasonable, the refractive index difference between the phosphor particles and the matrix glass is too large, and the prepared fluorescent glass has low transparency and poor optical performance.

The Chinese invention patent CN101643315B filed by Wuhan University of Technology, "Low-melting-point fluorescent glass for white light LED and its preparation method" discloses the preparation method of low-melting-point fluorescent glass containing YAG:Ce phase, and the matrix glass composition is SiO ₂ -Al ₂ O _3- B ₂ O ₃ -CaO-ZnO-Na ₂ O-MgO, the melting temperature is 900°C-1300°C.

In the prior art, the preparation temperature of glass ceramics is generally above 800°C. For example, in CN104445957A "a kind of oxyfluoride tellurate glass ceramics", the glass melting temperature is 1100°C; In "transparent oxyfluoride tellurate glass ceramics", the glass melting temperature is 850°C-1100°C, in the patent CN105198211A "a low-melting point glass powder and its preparation method", the melting temperature is 1000°C-1300°C.

Contents of the invention

In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a low-melting point tellurate glass-ceramic, a preparation method and an application thereof. The invention has the advantages of simple preparation process, low melting temperature, less energy consumption and short production cycle. The resulting glass-ceramics have the advantages of low melting temperature, high thermal conductivity and long lifetime.

The technical solution of the present invention is specifically introduced as follows.

A low-melting point tellurate glass ceramic, which is composed of glass raw material and YAG fluorescent powder; wherein: the glass raw material is composed of the following components in molar percentages: 50-70mol% TeO ₂ , 10-30mol% Na ₂ O, 5-25mol% ZnO, the sum of the mole fractions of each component is 100%; the mass of the fluorescent powder is 6-10% of the total mass of glass raw materials.

In the present invention, the source of the effective material Na ₂ O is Na ₂ CO ₃ .

In the present invention, the YAG phosphor is YAG:Ce phosphor.

In the present invention, the molar fraction of TeO ₂ is 53-65 mol%, the molar fraction of Na ₂ O is 13-26 mol%, and the molar fraction of ZnO is 9-22 mol%.

In the present invention, the molar fraction of TeO ₂ is 55-64 mol%, the molar fraction of Na ₂ O is preferably 14-24 mol%, and the molar fraction of ZnO is preferably 10-22 mol%.

In the present invention, the mass of the fluorescent powder is 7-9% of the total mass of the glass raw material.

The present invention also provides a method for preparing the above-mentioned low-melting point tellurate glass-ceramics, the specific steps are as follows: first, mix TeO ₂ , Na ₂ O, ZnO, and YAG fluorescent powder evenly and pour them into a crucible; Melt in a muffle furnace for 0.5h-2h; then pour the molten glass onto a mold at a temperature of 180-220°C for annealing treatment, and cool down to room temperature at the annealing temperature to obtain low melting point tellurate glass ceramics.

In the present invention, the temperature of the muffle furnace is 500-600° C., and the melting time is 0.5-1 h.

In the present invention, the crucible is a corundum crucible; the mold is a cast iron mold.

Furthermore, the present invention provides an application of the above-mentioned low melting point tellurate glass ceramics in the field of white light LEDs. The glass ceramic prepared by the invention generates strong white light when excited by a 460nm blue light source, and can be applied to white light LEDs.

Compared with the prior art, the beneficial effects of the present invention are:

(1) The present invention reduces the melting temperature of tellurate to 500-700° C. by introducing Na ₂ O components, the melting temperature is low, the energy consumption in the preparation process is reduced, and the production cost is reduced by using an alumina crucible;

(2) The preparation method is simple and the production cycle is short. The glass raw material and phosphor powder are directly mixed and fused into glass ceramics, and glass ceramics with different luminescence intensity are obtained by adjusting the doping ratio of phosphor powder. The increase of the phosphor ratio increases, and then weakens within a certain range with the increase of the phosphor ratio;

Description of drawings

FIG. 1 is an emission spectrum diagram of the glass-ceramic of Example 1.

FIG. 2 is an excitation spectrum diagram of the glass-ceramic of Example 1. FIG.

FIG. 3 is an emission spectrum diagram of the glass-ceramic of Example 2.

FIG. 4 is an excitation spectrum diagram of the glass ceramic of Example 2.

FIG. 5 is an emission spectrum diagram of the glass-ceramic of Example 3. FIG.

FIG. 6 is an excitation spectrum diagram of the glass-ceramic of Example 3. FIG.

Fig. 7 is a luminescence photo of the sample after coupling the glass ceramic of Example 1 with a blue light chip.

detailed description

The present invention will be described below through specific examples.

Example 1

Analytical pure TeO ₂ , Na ₂ O, ZnO, YAG phosphor, according to 63mol% TeO ₂ , 22mol% Na ₂ O, 15mol% ZnO, 7wt% phosphor (based on TeO ₂ , the ZnO total mass of Na ₂ O ) after being accurately weighed, placed in an agate mortar, ground evenly, placed in a corundum crucible, melted in a muffle furnace at 550°C for 1 hour, and then poured the glass melt onto a cast iron mold at 180°C for annealing After processing, take out the glass ceramics when the temperature drops to room temperature.

Adopt fluorescence spectrometer (FLS8900, British Edinburgh Instruments company) to measure the glass ceramics of above-mentioned gained, the spectrogram of gained is shown in Figure 1, as shown in Figure 2, under 460nm wavelength excitation, its emission wavelength is positioned at 576nm, corresponds to Ce ^{3 +} 's 5D ₁ → ² F _7/2 , using Hangzhou Yuanfang STC4000 fast spectrometer to couple glass ceramics with a 460nm blue light chip to emit bright white light, as shown in Figure 7.

Example 2

Analytical pure TeO ₂ , Na ₂ O, ZnO, YAG phosphor, according to 63mol% TeO ₂ , 22mol% Na ₂ O, 15mol% ZnO, 8wt% phosphor (based on TeO ₂ , the total mass of ZnO in Na ₂ O ) after being accurately weighed, placed in an agate mortar, ground evenly, placed in a corundum crucible, melted in a muffle furnace at 600°C for 1 hour, and then poured the glass melt onto a cast iron mold at 200°C for annealing After processing, take out the glass ceramics when the temperature drops to room temperature.

Adopt fluorescence spectrometer (FLS8900, U.K. Edinburgh Instruments company) to measure the glass ceramics of above-mentioned gained, the emission spectrogram of gained is shown in Figure 3, as shown in Figure 4, under 460nm wavelength excitation, its emission wavelength is positioned at 576nm, corresponds to Ce ³⁺ ’s 5D ₁ → ² F _7/2 , using Hangzhou Yuanfang STC4000 fast spectrometer to couple glass ceramics with a 460nm blue light chip, emit bright white light, and the measured light efficiency is higher than that of Examples 1 and 3.

Example 3

Analytical pure TeO ₂ , Na ₂ O, ZnO, YAG phosphor, according to 60mol% TeO ₂ , 22mol% Na ₂ O, 18mol% ZnO, 9wt% phosphor (based on TeO ₂ , the ZnO total mass of Na ₂ O ) after being accurately weighed, placed in an agate mortar, ground evenly, placed in a corundum crucible, melted in a muffle furnace at 700°C for 1 hour, and then poured the glass melt onto a cast iron mold at 220°C for annealing After processing, take out the glass ceramics when the temperature drops to room temperature.

Adopt fluorescence spectrometer (FLS8900, U.K. Edinburgh Instruments company) to measure the glass ceramics of above-mentioned gained, the emission spectrogram of gained is shown in Figure 5, as shown in Figure 6, under 460nm wavelength excitation, its emission wavelength is positioned at 576nm, corresponds to Ce ³⁺ 's 5D ₁ → ² F _7/2 , using Hangzhou Yuanfang STC4000 fast spectrometer to couple glass ceramics with a 460nm blue light chip to emit bright white light. The measured luminous efficiency is higher than that of Example 1, but higher than that of Example 2 Low.

Claims (9)

1. A low-melting point tellurate glass-ceramic, characterized in that it is composed of glass raw material and YAG fluorescent powder; wherein: the glass raw material is composed of the following molar percentage components, 50-70mol% TeO ₂ , 10-30mol% Na ₂ O, 5-25mol% ZnO, the sum of the mole fractions of each component is 100%; the mass of the fluorescent powder is 6-10% of the total mass of glass raw materials. 2. low melting point tellurate glass ceramics according to claim 1, is characterized in that, described YAG fluorescent powder is YAG:Ce phosphor. 3. low melting point tellurate glass ceramics according to claim ₁ , is characterized in that, TeO Mole fraction is 53-65mol%, the molar fraction of Na ₂ O is 13-26mol%, and the molar fraction of ZnO is 9-22mol%. 4. low melting point tellurate glass ceramics according to claim ₁ , is characterized in that, TeO Mole fraction is 55-64mol%, the molar fraction of Na ₂ O is preferably 14-24mol%, and the molar fraction of ZnO is preferably 10-22mol%. 5. The low-melting point tellurite glass-ceramic according to claim 1, characterized in that the mass of the fluorescent powder is 7-9% of the total mass of the glass raw materials. 6. A method for preparing the low-melting point tellurate glass-ceramic according to claim 1, characterized in that, the specific steps are as follows: first, TeO ₂ , Na ₂ O, ZnO, and YAG fluorescent powder are evenly mixed and poured into the crucible , melt in a muffle furnace at a temperature of 500-700°C for 0.5h-2h; then pour the molten glass onto a mold at a temperature of 180-220°C for annealing treatment, and cool the annealing temperature to room temperature to obtain a low melting point tellurate glass ceramics. 7. The preparation method according to claim 6, characterized in that the temperature of the muffle furnace is 500-600° C., and the melting time is 0.5-1 h. 8. The preparation method according to claim 6, wherein the crucible is a corundum crucible; and the mold is a cast iron mold. 9. An application of the low-melting point tellurate glass-ceramic according to claim 1 in the field of white light LEDs.