JP2017008162A - Yag-based fluophor and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology excellent in energy cost and capable of manufacturing a YAG-based fluophor in short time.SOLUTION: The manufacturing method of a YAG-based fluophor includes combustion synthesizing the YAG-based fluophor by using oxidation heat of metal Al powders with raw powders containing YOpowders, AlOpowders and metal Al powders as a raw material. It is preferably to set x in a range of 1.5 to 1.8 when a ratio of the YOpowders, the AlOpowders and the metal Al powders in the raw material, by molar ratio, is YO:AlO:Al=1.5:x:(5-2x).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technology that is excellent in energy cost and enables a YAG phosphor to be manufactured in a short time.

  LEDs are attracting attention as next-generation lighting that replaces incandescent bulbs and fluorescent lamps because of their high conversion efficiency and long life. Currently, light emitted from light-emitting elements is color-converted by phosphors and output. LEDs are the mainstream.

A typical phosphor used in such an LED is a YAG phosphor activated with Ce. A Ce-activated YAG (YAG: Ce) phosphor is formed by converting some Y atoms in Y ₃ Al ₅ O ₁₂ (yttrium, aluminum, garnet), which is a composite oxide of Y ₂ O ₃ and Al ₂ O ₃ , to Ce atoms. Is a phosphor that has a characteristic of absorbing blue light (wavelength of about 460 nm) and emitting yellow light (wavelength of about 530 nm) in combination with a blue LED developed in the early 1990s. Thus, pseudo white light combining blue light and yellow light can be obtained. Therefore, currently, it is widely used for white LEDs (for example, Patent Document 1 (Patent No. 3503139) and Patent Document 2 (Patent Document 2). No. 3700502))).

  Such a phosphor requires a large amount of energy when manufactured. For example, in paragraph 0003 of Patent Document 3 (Japanese Patent Application Laid-Open No. 2014-148677), “YAG phosphors are generally prepared at a high temperature (above about 1600 ° C.) via a solid-phase reaction method.” The high temperature heat treatment requires several hours.

Japanese Patent No. 3503139 Japanese Patent No. 3700502 Japanese Patent Laid-Open No. 2014-148677 JP 2005-305320 A

Zuhair A. Munir et al. Self-propagating exothermic reactions: The synthesis of high-temperature materials by combustion, Materials Science Reports, 3, (1989), p277-365. Combustion Synthesis Study Group, “Chemistry of Combustion Synthesis: Instant Process of Material Synthesis and Processing”, p32-33 (1992). Y. Song et al, "Predicting the Adiabatic Temperature of Transparent Y3Al5O12 Prepared via Combustion Synthesis under Ultra-High Gravity", Materials Transactions, 51, (2010), p2230-2235. The Japan Institute of Metals, Introduction to Metal Chemistry Series 1 “Metal Physical Chemistry” (1996), p31-33. T.Hirano et al. Self-propagating high-temperature synthesis of Sr-doped LaMnO3perovskite as oxidation catalyst, Alloys and Compounds, 441, (2007), p263-266. V. Bachmann et al. Temperature Quenching of Yellow Ce3 + Luminescence in YAG: Ce, Chem. Mater., 21, (2009), p2077-2084. C.W.Won et al. Efficient solid-state route for the preparation of spherical YAG: Ce phosphor particles, Alloys and Compounds, 509, (2011), p2621-2626.

  A combustion synthesis method is known as a technique that enables energy-saving and short-time material synthesis compared to conventional synthesis methods. This synthesis method continuously synthesizes materials using the self-propagation of combustion waves generated during the combustion reaction. Since this method uses self-heating during compound synthesis, it is also known as the SHS method (Self-propagating High -temperature synthesis).

  In the combustion synthesis method, the exothermic reaction between the raw material powders as raw materials proceeds in a chain reaction in a short time in seconds, and the target compound is synthesized continuously and in a short time, so there is almost no external energy supply. The manufacturing time can be shortened, the structure of the manufacturing apparatus can be simplified, and the cost for material synthesis can be reduced.

  However, until now, there have been few reports on application examples of the combustion synthesis method to the synthesis of YAG-based phosphors, and the actual condition is that the conditions for synthesizing YAG phosphors with excellent fluorescence characteristics have not been studied. .

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to clarify suitable conditions for producing a YAG phosphor by a combustion synthesis method, and is excellent in energy cost and in a short time. The object is to provide a technique that makes it possible to produce a YAG phosphor.

In order to solve the above-mentioned problems, a method for producing a YAG phosphor according to the present invention uses raw powder containing yttrium oxide (Y ₂ O ₃ ) powder, aluminum oxide (Al ₂ O ₃ ) powder, and metal Al powder as a raw material. A YAG (Y ₃ Al ₅ O ₁₂ ) -based phosphor is combusted and synthesized using the heat of oxidation of the metal Al powder.

Preferably, the molar ratio of Y ₂ O ₃ powder, Al ₂ O ₃ powder and metal Al powder in the raw material is Y ₂ O ₃ : Al ₂ O ₃ : Al = 1.5: x: (5 -2x), x is set in the range of 1.5 to 1.8.

In one embodiment, a cerium oxide (CeO ₂ ) powder is further added to the raw material, and the molar ratio of the Y ₂ O ₃ powder, the CeO ₂ powder, the Al ₂ O ₃ powder, and the metal Al powder is calculated. And Y ₂ O ₃ : CeO ₂ : Al ₂ O ₃ : Al = (1.5−α): 2α: x: (5-2x), x is in the range of 1.5 to 1.8. Set to.

  At this time, preferably, the ratio of α and (1.5−α) defined by 2α / [2 (1.5−α) + 2α] is set to 1.0% or more and 5.0% or less. To do.

  In these embodiments, more preferably, the x is set in the range of 1.70 to 1.75.

  A perchlorate may be added to the raw material as an oxygen supply agent.

For example, the oxygen supply agent is NaClO ₄ .

In one embodiment, barium fluoride (BaF ₂ ) powder is further added to the raw material.

Preferably, the addition amount of the BaF ₂ powder is set in a range of 4 to 6 wt% with respect to the total amount of raw material powder.

Preferably, the Al ₂ O ₃ powder and the metal Al powder are those having a purity of 99.99% or more.

  The YAG phosphor according to the present invention is a YAG phosphor synthesized by any one of the methods described above.

  According to the present invention, suitable conditions for producing a YAG phosphor by a combustion synthesis method are clarified, and as a result, a technology is provided that is excellent in energy cost and can produce a YAG phosphor in a short time. .

It is the adiabatic flame temperature when the addition amount x of the Al ₂ O ₃ elementary powder contained in the raw material is used as a parameter. It is the schematic of a combustion synthesis apparatus, (a) is a top view, (b) is sectional drawing. It is an optical photograph of the sample obtained by carrying out combustion synthesis on the conditions of x = 1.5-1.9. It is a X-ray diffraction chart of YAG: Ce (Ce content is 1 at%) of x = 1.5 to 1.8 among samples synthesized by combustion. It is a luminescence intensity measurement result of YAG: Ce (Ce content is 1 at%) of x = 1.5 to 1.8 among the samples synthesized by combustion. It is an X-ray diffraction chart of YAG: Ce (Ce content is 1.0 at%) obtained by combustion synthesis under the condition of x = 1.70. It is an X-ray diffraction chart of YAG: Ce (Ce content is 1.0 at%) obtained by combustion synthesis under the condition of x = 1.725. It is an X-ray diffraction chart of YAG: Ce (Ce content is 1.0 at%) obtained by combustion synthesis under the condition of x = 1.75. It is a luminescence intensity measurement result of YAG: Ce (Ce content is 1.0 at%) obtained by combustion synthesis under the condition of x = 1.70. It is a luminescence intensity measurement result of YAG: Ce (Ce content is 1.0 at%) obtained by combustion synthesis under the condition of x = 1.725. It is a luminescence intensity measurement result of YAG: Ce (Ce content is 1.0 at%) obtained by combustion synthesis under the condition of x = 1.75. It is the figure which compared the emitted light intensity of three YAG: Ce combustion-synthesized on the conditions of x = 1.70, x = 1.725, x = 1.75. X-ray diffraction charts of five YAG: Ce (Ce: 1.0 at%, 2.0 at%, 3.0 at%, 4.0 at%, 5.0 at%) synthesized by combustion under the condition of x = 1.725 It is. It is the figure which compared the emitted light intensity of five YAG: Ce. ₂ is an X-ray diffraction chart of a YAG: Ce sample burned and synthesized with BaF ₂ added as a flux and a YAG: Ce sample burned and synthesized without adding BaF ₂ . Five out as shown in FIG. 15, four YAG obtained by performing combustion synthesis of BaF ₂ as a flux: is a graph comparing the emission intensity of Ce.

  Hereinafter, a method for producing a YAG phosphor according to the present invention will be described with reference to the drawings. In the following description, Ce is exemplified as the activator, but europium (Eu), ytterbium (Yb), chromium (Cr), or the like may be used.

  In the combustion synthesis method, control of the adiabatic flame temperature is important. It is known that the reaction does not propagate when the adiabatic flame temperature is 1800 K or less, and conversely, when the temperature is higher than this, the target compound is not generated due to fusion of raw materials (Non-patent Document 1).

As a result of sincerity studies, the present inventors have examined the use of oxidation heat of metal Al powder when producing a YAG-based phosphor by a combustion synthesis method, and have achieved the present invention. That is, in the method for producing a YAG phosphor according to the present invention, a YAG-based phosphor is produced by using raw powder containing Y ₂ O ₃ powder, Al ₂ O ₃ powder, and metal Al powder as a raw material, and utilizing the oxidation heat of the metal Al powder. Combustion synthesis of phosphor.

Furthermore, the present inventors provide an additive amount of Al ₂ O ₃ and a raw material suitable for improving the characteristics when the YAG: Ce phosphor obtained by the combustion synthesis reaction is subjected to combustion synthesis. The purity of the elementary powder, the Ce concentration, and the amount of BaF ₂ added as a flux were also examined.

[Examination of Al ₂ O ₃ Addition]
The present inventors examined the use of Al ₂ O ₃ as an Al source of YAG as a diluent for controlling the reaction temperature, and examined the appropriate addition amount.

Prior to the experiment, the adiabatic flame temperature (T _ad ) was calculated as follows.

The adiabatic flame temperature refers to the highest temperature achieved during combustion under completely adiabatic. The adiabatic flame temperature is based on the assumption that all of the production enthalpy, defined as the enthalpy difference (-ΔH _T0 ) between the raw and product systems at the reaction start temperature (T _o ), was used to increase the product temperature. It can obtain | require from the following Formula (1)-(4) (nonpatent literature 2).

Where Cp (s) is the heat capacity of the solid product, Cp (l) is the heat capacity in the molten state, Cp (g) is the heat capacity in the gaseous state, T _m is the melting point of the product, T _b is the boiling point of the product, ΔH _m is the heat of fusion, ΔH _e is the heat of evaporation, ν _m is the rate of melting when the product is melted, and ν _e is the rate of evaporation when the product is evaporated.

The following equation (5) is a chemical reaction formula of the combustion synthesis reaction of YAG when the addition amount of Al ₂ O ₃ is used as a parameter.

  In the above equation (5), y is about (7.5-3x) / 4 (y≈ (7.5-3x) / 4).

In calculating the enthalpy of formation in the combustion synthesis of YAG, the value of each enthalpy shown in Table 1 (the unit is kJ / mol) was used. Here, [Delta] H ⁰ ₂₉₈ generating heat, [Delta] H _m is the heat of fusion, [Delta] H _e is the heat of vaporization. The value of the heat of formation ΔH ⁰ ₂₉₈ of YAG and the value of the heat of fusion ΔH _m are according to Non-Patent Document 3.

Moreover, the molar specific heat (C _p ) of the product was calculated using the following formulas (6) to (11) (see Non-Patent Document 3 and Non-Patent Document 4).

Using the data shown in Table 1 above, the enthalpy of formation of YAG containing NaCl as a byproduct is calculated, and the temperature T at which the above equations (1) to (4) are established using the above equations (6) to (11). Was determined as the adiabatic flame temperature _Tad .

In the above procedure, it calculates the adiabatic flame temperature T _ad in the range of x = from 1.5 to 2.25, have created a schematic diagram of adiabatic flame temperature change of the reaction in which the x and parameters.

FIG. 1 shows the adiabatic flame temperature when the addition amount x of the Al ₂ O ₃ elementary powder to be contained in the raw material prepared by the above method is used as a parameter. It can be seen from FIG. 1 that, under completely adiabatic, x is about 2.0 or less and YAG melts during the reaction.

Using the dependency of the adiabatic flame temperature obtained as described above on the amount of Al ₂ O ₃ powder added as a guide, the amount x of Al ₂ O ₃ powder added to obtain a YAG: Ce phosphor with high fluorescence characteristics was examined. did.

As raw materials, Y ₂ O ₃ powder (manufactured by Kanto Chemical: purity 99.99%), CeO ₂ powder (manufactured by high purity chemical: purity 99.99%, average diameter 0.2 μm), metal Al powder (manufactured by high purity chemical) : Purity 99.9%, average diameter 3 μm), Al ₂ O ₃ powder (manufactured by Kishida Chemical: purity 99.0%), NaClO ₄ powder (manufactured by ALDRICH: purity 98.0%). A YAG phosphor (YAG: Ce) containing 0 at% was synthesized by combustion. The reaction formula in that case becomes the following formula (12). Here, the NaClO ₄ is used as an oxygen supply agent, and the present invention is not limited to this, and other perchlorates may be used.

  In the above equation (12), y is about (7.485-3x) / 4 (y≈ (7.485-3x) / 4).

  Using the adiabatic flame temperature during YAG synthesis (FIG. 1) as a guide, each elementary powder was weighed in the range of x = 1.5 to 1.9 according to the stoichiometric ratio determined by the above equation (12). After the weighed elementary powder is mixed with a rolling ball mill (4 hours at 100 rpm), the mixed powder is sealed in a crucible with a graphite lid (length 12 cm x width 4 cm x depth 3.5 cm) and insulated in the combustion synthesizer. Installed with materials. The inside of the combustion synthesizer was evacuated with a rotary pump, and then an atmospheric pressure Ar atmosphere was established.

  2A and 2B are schematic views of the above-described combustion synthesis apparatus 100, in which FIG. 2A is a top view and FIG. 2B is a cross-sectional view (see Non-Patent Document 5). In the figure, reference numeral 10 is a mixed powder (sample) as a raw material, reference numeral 20 is a crucible, reference numeral 30 is a heat insulating material, reference numeral 40 is a carbon foil, reference numeral 50 is a rotary pump, reference numeral 60 is a gas inlet, and reference numeral 70 is a gas. A discharge port 80 is a control box.

  After ignition, for safety, the crucible 20 was cooled in the apparatus 100 for about 4 hours, and the sample 10 was taken out. The obtained sample 10 was pulverized by hand in a tungsten carbide steel mortar after removing the ignition portion. The pulverized sample 10 was put in a beaker together with hot water, stirred and washed with a magnetic stirrer, filtered with a suction filter, and dried in a dryer. Finally, the dried powder was sieved, and the powder having a particle size in the range of 150 to 355 μm was collected and used as an evaluation sample.

  For these samples, products were identified by X-ray diffraction (MiniFlex Rigaku), and fluorescence intensity was measured by a fluorescence spectrometer (FP-6200 JASCO). The optimum value of x was determined from the XRD measurement result and the emission intensity measurement result of the sample.

  FIG. 3 is an optical photograph of a sample obtained by combustion synthesis under the above conditions (x = 1.5 to 1.9).

  The white material is NaCl produced as a by-product. This can be removed by washing with hot water after pulverization. The samples with x = 1.5 and 1.6 were considered to be in a fused state that the product melted because the reaction temperature in the crucible greatly exceeded the melting point of YAG, and could be confirmed with a photograph. . Further, NaCl vaporizes at the same time as its generation, and the sample may be scattered with the vaporization.

  Also, the reaction propagates up to x = 1.8, but it can be seen that the reaction did not propagate at x = 1.9. From this, it was concluded that combustion synthesis of YAG: Ce is possible in the range of x = 1.5 to 1.8.

Therefore, the ratio of Y ₂ O ₃ powder, Al ₂ O ₃ powder and metal Al powder in the raw material in terms of molar ratio is Y ₂ O ₃ : Al ₂ O ₃ : Al = 1.5: x: (5-2x) X is preferably set in the range of 1.5 to 1.8.

When YAG is doped with Ce, the ratio of Y ₂ O ₃ powder, CeO ₂ powder, Al ₂ O ₃ powder and metal Al powder in terms of molar ratio is Y ₂ O ₃ : CeO ₂ : Al ₂ O ₃ : Al = When (1.5−α): 2α: x: (5-2x), x is preferably set in the range of 1.5 to 1.8. As will be described later, the ratio of α defined by 2α / [2 (1.5−α) + 2α] and (1.5−α) is set to 1.0% or more and 5.0% or less. It is preferable to do.

It is considered that the unreacted product or the intermediate product YAP (YAlO ₃ ) remains in the gray portion seen on the surface of the sample of x = 1.7 to 1.8. In addition, it can be seen that the surface residue is less when x = 1.7 to 1.75 than when x = 1.8.

  FIG. 4 is an X-ray diffraction chart of YAG: Ce (Ce content is 1 at%) of x = 1.5 to 1.8 among samples synthesized by combustion under the above conditions. The peak indicated by a mark corresponds to the YAG peak. In any sample, the diffraction peak is substantially the same as that of YAG, and it can be seen that the sample obtained by the combustion synthesis described above has a YAG structure.

In the charts obtained from the samples of x = 1.750 and 1.800, a very weak peak (indicated by a Δ mark) is observed in the vicinity of 2θ = 35 °, which is YAP (YAlO ₃ ). Considered to be from. YAP is a compound frequently generated when YAG is synthesized by a solid-phase reaction method, and is easily generated when the heat treatment temperature is insufficient.

  FIG. 5 shows the emission intensity measurement result of YAG: Ce (Ce content is 1 at%) of x = 1.5 to 1.8 among the samples synthesized by combustion under the above conditions. When the sample is irradiated with blue light of 460 nm, yellow light of about 530 nm is obtained. The emission intensity of x = 1.5 is relatively low, but high emission intensity is obtained when x = 1.6 or more, particularly x = 1.7 or more. Among these samples, the sample that showed the highest emission intensity was x = 1.7.

  Based on the results of these luminescence intensity measurements and the results of x = 1.7 to 1.75 as described above, it was seen that there were few surface residues, x was 1.70 to 1.75. It was determined that it was preferable to set the value within the range.

[Examination of purity of raw powder used as raw material]
The effect of the purity of the raw powder used as a raw material on the quality (luminescence characteristics) of the YAG phosphor obtained by combustion synthesis was examined.

Specifically, among the above-mentioned elementary powders, Y ₂ O ₃ powder (manufactured by Kanto Chemical: purity 99.99%), CeO ₂ powder (manufactured by high purity chemical: purity 99.99%, average diameter 0.2 μm) The purity of NaClO ₄ powder (manufactured by ALDRICH: purity 98.0%) remains the same, and the metal Al powder has a purity of 4N of 99.99% (manufactured by high purity chemical: purity 99.99%, average diameter 45 μm). The Al ₂ O ₃ powder used was also 4N having a purity of 99.99% (manufactured by Koyo Chemical Co., Ltd .: purity 99.99%). And each elementary powder was weighed so that the value of x would be 1.70, 1.725, 1.75, and YAG: Ce was burned and synthesized.

  6 to 8 show X-rays of YAG: Ce (Ce content is 1.0 at%) obtained by combustion synthesis under the conditions of x = 1.70, x = 1.725, and x = 1.75, respectively. It is a diffraction chart.

For comparison, 3N metal Al powder (manufactured by High-purity Chemical: purity 99.9%, average diameter 3 μm) and 2N Al ₂ O ₃ powder (manufactured by Kishida Chemical: purity 99.0%) were used. An X-ray diffraction chart of YAG: Ce (Ce content is 1.0 at%) obtained by combustion synthesis is also shown.

  As can be seen from the X-ray diffraction charts shown in these drawings, no difference can be confirmed between the sample combusted and synthesized from the low-purity raw material and the sample combusted and synthesized from the high-purity raw material.

  9 to 11 are respectively YAG: Ce (Ce content is 1.) obtained by combustion synthesis under the conditions of x = 1.70, x = 1.725, and x = 1.75 using high-purity raw materials. For comparison, the results of measuring the emission intensity of YAG: Ce (Ce content is 1.0 at%) synthesized by combustion from a low-purity raw material are also shown.

  In any of the three conditions of x = 1.70, x = 1.725, and x = 1.75, the emission intensity of the sample synthesized by combustion from the high purity raw material is that of the sample synthesized by combustion from the low purity raw material. The value is higher.

  FIG. 12 is a graph comparing the emission intensities of these three YAG: Ce, and no significant difference is observed in the intensities.

That is, in order to improve the quality (light emission characteristics) of the YAG phosphor obtained by combustion synthesis, it is preferable to use Al ₂ O ₃ powder and Al powder having a purity of 99.99% or more.

[Examination of Ce concentration]
As raw materials, Y ₂ O ₃ powder (manufactured by Kanto Chemical: purity 99.99%), CeO ₂ powder (manufactured by high purity chemical: purity 99.99%, average diameter 0.2 μm), metal Al powder (manufactured by high purity chemical) : Purity 99.99%, average diameter 45 μm), Al ₂ O ₃ powder (product of high purity chemical: purity 99.99%), NaClO ₄ powder (product of ALDRICH: purity 98.0%), and Ce as 1 A YAG phosphor (YAG: Ce) containing 0.0 at%, 2.0 at%, 3.0 at%, 4.0 at%, and 5.0 at% was synthesized by combustion. The condition at this time was x = 1.725. The reaction formulas at the time of each synthesis are as shown in the following formulas (13) to (17).

  FIG. 13 is an X-ray diffraction chart of five samples combusted and synthesized under the above conditions. As described with reference to FIG. 4, the peak indicated by a circle is coincident with the YAG peak. In any sample, the diffraction peak is substantially the same as that of YAG, and it can be seen that the sample obtained by the combustion synthesis described above has a YAG structure.

A relatively strong peak due to YAP is observed from a sample in which the design value of Ce content is 5%. This is presumably due to the fact that since the amount of CeO ₂ added is relatively large, the reaction temperature was lowered and a large amount of intermediate product was produced.

  FIG. 14 is a diagram comparing the light emission intensities of these five YAG: Ce, and the light emission intensity of the sample with the Ce content design value of 1% is relatively low, but the other light emission intensities are almost the same. Among them, the emission intensity of the sample having the design value of Ce content of 4% is the highest.

  Although it can be seen that the emission intensity of the sample with a design value of Ce content of 5% is lower than that of the sample with 4%, this may be due to causes such as concentration quenching.

  In general, when the amount of ions (here, Ce ions) involved in light emission in the phosphor increases, the amount of light emission tends to increase. However, when the number of ions increases, the light emission intensity decreases. This phenomenon is a phenomenon called concentration quenching or reabsorption, in which energy transfer other than light emission occurs due to excessive emission of ions, or other ions absorb light emitted from ions. Is known (Non-Patent Document 6).

It can also be seen that the wavelength of the emission band (near 530 nm) is slightly red-shifted to the longer wavelength side. It is known that the red transition of the emission band becomes larger as the Ce concentration of the YAG: Ce phosphor increases, and this phenomenon is considered to be involved in light emission due to the 5d → 4f transition of Ce ³⁺ ions. (Non-Patent Document 6).

  In the subsequent experiments, the condition that showed the highest emission intensity and the design value of Ce content was 4% was adopted as the combustion synthesis condition.

[Examination of the amount of BaF ₂ added as flux]
Flux is known to have an effect of lowering the temperature required for the synthesis and improving the homogeneity when synthesizing a complex oxide or the like, and BaF ₂ , CaF ₂ , NaCl, or the like is used. Among these, BaF ₂ is advantageous in that it is relatively inexpensive and has a relatively high melting point of 1626K, and can be almost removed by washing with hot water (see Patent Document 4 and Non-Patent Document 7). . Therefore, the present inventors examined the amount of BaF ₂ added as a flux.

A powder of BaF ₂ (manufactured by Wako Pure Chemicals, purity 99.9%) as a flux was added in an amount of 3.0 to 6.0 wt%, and combustion synthesis represented by the above formula (16) was performed to obtain a YAG: Ce sample (containing Ce). 4at%). For comparison, combustion synthesis was also performed under the same conditions except that BaF ₂ was not added.

FIG. 15 is an X-ray diffraction chart of these five YAG: Ce samples. In a sample obtained by performing combustion synthesis by adding 5.0 wt% of BaF ₂ , a peak due to YAP near 2θ = 34 ° is hardly observed.

FIG. 16 is a diagram comparing the light emission intensities of four YAG: Ce obtained by performing combustion synthesis using BaF ₂ as a flux among the above five, and the light emission of the sample with an addition amount of BaF ₂ of 3 wt%. strength is relatively low, but the emission intensity of those BaF ₂ amount 4～6Wt% is generally the same, the highest emission intensity of BaF ₂ amount 5 wt% of the sample therein. From this result, it was judged that the addition amount of BaF ₂ is preferably set in the range of 4 to 6 wt%.

[Comparison with YAG phosphor synthesized by solid-phase reaction method]
The above-mentioned emission characteristics of the YAG phosphor obtained by the combustion synthesis method were compared with the emission characteristics of the YAG phosphor synthesized by the solid phase reaction method.

  As a sample for that purpose, YAG: Ce (Ce content: 1.0 at%) was synthesized according to the reaction formula of the following formula (18).

  The mixed elementary powder (about 1 g) was put in an alumina crucible and heat-treated at 1450 ° C. for 4 hours in an air atmosphere.

  When the emission characteristics (emission intensity) of the obtained YAG: Ce sample were evaluated, it was confirmed that the emission intensity was lower than that of the YAG phosphor obtained by the combustion synthesis method.

  According to the present invention, suitable conditions for producing a YAG phosphor by a combustion synthesis method are clarified, and as a result, a technology that is excellent in energy cost and enables production of a YAG phosphor in a short time is provided. .

10 Mixed powder (sample)
20 crucible 30 heat insulating material 40 carbon foil 50 rotary pump 60 gas inlet 70 gas outlet 80 control box 100 combustion synthesis apparatus

Claims (11)

A raw powder containing yttrium oxide (Y ₂ O ₃ ) powder, aluminum oxide (Al ₂ O ₃ ) powder, and metal Al powder is used as a raw material, and YAG (Y ₃ Al ₅ O ₁₂₎ is utilized using the heat of oxidation of the metal Al powder. ) A method for producing a YAG-based phosphor, in which a phosphor is synthesized by combustion. The molar ratio of Y ₂ O ₃ powder, Al ₂ O ₃ powder and metal Al powder in the raw material is Y ₂ O ₃ : Al ₂ O ₃ : Al = 1.5: x: (5-2x) The method for producing a YAG phosphor according to claim 1, wherein x is set in a range of 1.5 to 1.8. A cerium oxide (CeO ₂ ) powder is further added to the raw material, and the ratio of the Y ₂ O ₃ powder, the CeO ₂ powder, the Al ₂ O ₃ powder, and the metal Al powder in terms of molar ratio is Y ₂ O. ₃ : CeO ₂ : Al ₂ O ₃ : Al = (1.5−α): 2α: x: When (5-2x), the x is set in the range of 1.5 to 1.8. The manufacturing method of the YAG type | system | group fluorescent substance of Claim 1.   The ratio of α and (1.5−α) defined by 2α / [2 (1.5−α) + 2α] is set to 1.0% or more and 5.0% or less. The manufacturing method of YAG type fluorescent substance of description.   The method for producing a YAG phosphor according to any one of claims 2 to 4, wherein x is set in a range of 1.70 to 1.75.   The method for producing a YAG phosphor according to any one of claims 1 to 5, wherein a perchlorate is further added to the raw material as an oxygen supply agent. The method for producing a YAG phosphor according to claim 6, wherein the oxygen supply agent is NaClO ₄ . The method for producing a YAG phosphor according to any one of claims 3 to 7, wherein barium fluoride (BaF ₂ ) powder is further added to the raw material. The method for producing a YAG phosphor according to claim 8, wherein the addition amount of the BaF ₂ powder is set in a range of 4 to 6 wt% with respect to the total amount of raw material powder. The method for producing a YAG phosphor according to any one of claims 1 to 9, wherein the Al ₂ O ₃ powder and the metal Al powder are those having a purity of 99.99% or more.   A YAG phosphor synthesized by the method according to any one of claims 1 to 10.