JP2020083945A - METHOD FOR PRODUCING β-TYPE SIALON PHOSPHOR - Google Patents

Abstract

To provide a method for producing β-type sialon phosphor, in which the brightness of β-type sialon phosphor can be improved.SOLUTION: Provided is a method for producing β-type sialon phosphor, which is a method for producing β-type sialon phosphor having solid solution of europium, and including a first calcination step in which a first raw material powder containing a first europium compound is calcined in order to obtain a first calcination powder containing β-type sialon particles, and a second calcination step in which the obtained first calcination powder and a second raw material powder containing a second europium compound are calcined in order to decrease the content of Eu element in the first calcination powder.SELECTED DRAWING: None

Description

The present invention relates to a method for producing a β-sialon phosphor.

A light emitting device is known in which a light emitting element that emits primary light and a phosphor that absorbs primary light and emits secondary light are combined.
In recent years, the demand for heat resistance and durability of phosphors has increased with the increase in the output of light emitting devices, and β-sialon phosphors having a stable crystal structure have attracted attention.

Examples of the technique relating to such β-sialon phosphor include those described in Patent Documents 1 to 3 below.

Patent Document 1 (JP-A-2018-002870) describes a first firing step of firing a mixed powder of at least silicon nitride, aluminum nitride and an Eu compound at 1550 to 2100° C. in a nitrogen atmosphere, and a firing powder thereof. A second firing step of adding one or more powders selected from silicon nitride, silicon oxide, aluminum nitride, aluminum oxide, and europium oxide, and firing at 1900 to 2100° C. in a nitrogen atmosphere to obtain a fired product; Method for producing β-sialon phosphor containing Eu as an emission center, which comprises an annealing step of heating the above at a second firing temperature or less in a non-oxidizing atmosphere other than pure nitrogen, and an acid treatment step of subjecting the annealed powder to an acid treatment Is listed.

In Patent Document 2 (JP 2013-173868 A), in a method for producing a phosphor having β-sialon as a host crystal, at least two firing steps are performed, and an activator element is added in the first firing step. The phosphor material for the first firing, which was made to have a concentration lower than the concentration to be obtained, was prepared, and this was fired, and the obtained raw material for the first firing was further added to the phosphor material for the second firing in which an activator element was added. A method for producing a β-sialon phosphor, which is characterized by firing, is described.

Patent Document 3 (JP-A-2017-2278) discloses a first heat treatment step of heat-treating a mixture containing an aluminum compound, a first europium compound and silicon nitride to obtain a first heat-treated product, and a first heat treatment process. A method for producing a β-sialon phosphor is described, which comprises a second heat treatment step of obtaining a second heat-treated product by heat-treating the heat-treated product and a second europium compound in a rare gas atmosphere.

JP, 2008-002870, A JP, 2013-173868, A JP, 2017-2278, A

The β-sialon phosphor is required to have further improved brightness.

The present invention has been made in view of the above circumstances, and provides a method for producing a β-sialon phosphor capable of improving the brightness of the β-sialon phosphor.

The present inventors have earnestly studied to achieve the above object. As a result, a europium compound, which is one of the raw materials for the β-sialon phosphor, was added in two or more times and the firing process was performed. The β-sialon phosphor was obtained in the first firing process. It was found that the brightness of the obtained β-sialon phosphor is improved by controlling the second firing step so that the content of Eu element in the fired powder is reduced, and the present invention has been completed. ..

That is, according to the present invention, the following method for producing a β-sialon phosphor is provided.

[1]
A method for producing a β-sialon phosphor having europium as a solid solution,
A first firing step of firing a first raw material powder containing a first europium compound to obtain a first fired powder containing β-sialon particles,
A second firing step of reducing the content of the Eu element in the first fired powder by firing the obtained second fired powder containing the first fired powder and the second europium compound;
A method for producing a β-sialon phosphor containing:
[2]
In the method for producing a β-sialon phosphor according to the above [1],
When the total of the first baked powder and the second europium compound is 100% by mass,
A method for producing a β-sialon phosphor, wherein the ratio of the second europium compound is 1.0% by mass or more and 18.0% by mass or less.
[3]
In the method for producing a β-sialon phosphor according to the above [1] or [2],
When the total of the first baked powder and the second europium compound is 100% by mass,
A method for producing a β-sialon phosphor, wherein the proportion of the second europium compound is 2.0% by mass or more and 17.0% by mass or less.
[4]
In the method for producing a β-sialon phosphor according to any one of [1] to [3] above,
The method for producing a β-sialon phosphor, wherein the second europium compound contains europium oxide.
[5]
In the method for producing a β-sialon phosphor according to any one of [1] to [4] above,
Production of β-sialon phosphor in which the total amount of europium contained in the first raw material powder and the second raw material powder is 3 times or more the amount of europium solid-dissolved in the finally obtained β-sialon phosphor. Method.
[6]
In the method for producing a β-sialon phosphor according to any one of [1] to [5] above,
A method for producing a β-sialon phosphor, wherein the amount of europium contained in the first raw material powder is larger than the amount of europium solid-dissolved in the finally obtained β-sialon phosphor.
[7]
In the method for producing a β-sialon phosphor according to any one of the above [1] to [6],
A method for producing a β-sialon phosphor, wherein the firing temperature in the second firing step is 1800° C. or higher and 2100° C. or lower.
[8]
In the method for producing a β-sialon phosphor according to any one of the above [1] to [7],
A method for producing a β-sialon phosphor, wherein the firing temperature in the first firing step is 1800° C. or higher and 2100° C. or lower.
[9]
In the method for producing a β-sialon phosphor according to any one of the above [1] to [8],
The method for producing a β-sialon phosphor, further comprising an annealing step of heating at a temperature lower than the firing temperature of the second firing step after the second firing step.
[10]
In the method for producing a β-sialon phosphor according to any one of [1] to [9] above,
The method for producing a β-sialon phosphor further comprising a step of subjecting the second baked powder obtained in the second baking step or an annealed product of the second baked powder to an acid treatment, an alkali treatment and/or a fluorine treatment.

According to the present invention, it is possible to provide a method for producing a β-sialon phosphor capable of improving the brightness of the β-sialon phosphor.

Hereinafter, preferred embodiments of the present invention will be specifically described, but the present invention should not be construed as being limited thereto, and is based on the knowledge of those skilled in the art without departing from the gist of the present invention. , Various changes and improvements can be made. A plurality of constituent elements disclosed in the embodiments can form various inventions by an appropriate combination. For example, some constituent elements may be deleted from all the constituent elements shown in the embodiments, or constituent elements of different embodiments may be appropriately combined. Unless otherwise specified, “A to B” in the numerical range represents A or more and B or less.

The method for producing a β-sialon phosphor according to the present embodiment relates to a method for producing a β-sialon phosphor in which europium is in solid solution, and more specifically, the β-sialon is used as a host crystal and as an emission center. The present invention relates to a method for producing a β-sialon phosphor containing europium.
In the β-sialon phosphor, β-sialon, which is a host crystal, is represented by the general formula: Si _6-Z Al _Z O _Z N _8-Z (0<Z≦4.2), and the Z value and the content of europium. Is not particularly limited, but the Z value is, for example, more than 0 and 4.2 or less, preferably 0.005 or more and 1.0 or less, and the europium content is 0.1% by mass or more and 2.0 or less. It is preferably not more than mass %.

The method for producing a β-sialon phosphor according to this embodiment includes at least the following two firing steps. That is, the manufacturing method of the β-sialon phosphor according to the present embodiment, the first raw material powder containing the first europium compound is fired, the first firing step to obtain a first fired powder containing β-sialon particles, And a second firing step of reducing the content of the Eu element in the first fired powder by firing the obtained second raw material powder containing the first fired powder and the second europium compound.
Here, in the second firing step, as a method for reducing the content of the Eu element in the first fired powder obtained in the first firing step, for example, a second europium compound is added more than the conventional standard. A method, more specifically, a method of adding the second europium compound so that the amount of Eu is more than the amount of Eu that can be solid-dissolved in β-sialon in the second firing step.
In the second firing step, by adding the second europium compound so that the Eu amount becomes larger than the Eu amount that can be solid-dissolved in β-sialon, the first fired powder in the first firing step obtained in the first firing step is added. The reason why the content of the Eu element decreases is not clear, but it is considered that Eu is precipitated as a different phase component together with Al and Si in the second firing step. Here, the different phase component is, for example, a particle such as an oxide containing Eu element, Al element, and Si element.
The method for producing the β-sialon phosphor may further include one or more third firing steps of further firing the second fired powder to obtain the third fired powder, in which case a europium compound is further added. May be added.

Here, in the present embodiment, the “first firing step” means the first firing step of heat-treating the raw material powder containing the first europium compound, and the “second firing step” means the second europium. It means a second firing step of adding a compound and heat treatment, and the "third firing step" means a firing step performed after the second firing step.
Further, in the present embodiment, the "first europium compound" means a europium compound added in the first firing step, and the "second europium compound" means a europium compound added in the second firing step. Means
In the present embodiment, the “first raw material powder” means the raw material powder used in the first firing step, and the “second raw material powder” is the raw material powder used in the second firing step. It is preferable that the respective raw material powders are mixed.
Further, in the present embodiment, the "first baked powder" means a product obtained in the first baking step, and the "second baked powder" means a product obtained in the second baking step. However, the "third baked powder" means the product obtained in the third baking step.

In addition, in the present embodiment, the term “process” includes not only an independent process but also a term that is included in this term if the intended purpose of the process is achieved even when it cannot be clearly distinguished from other processes. Be done. The content of europium in the composition means the total amount of the plurality of materials present in the composition, unless a plurality of materials corresponding to europium are present in the composition, unless otherwise specified.

The first raw material powder preferably contains silicon nitride and aluminum nitride in addition to the first europium compound. Silicon nitride and aluminum nitride are materials for forming a β-sialon skeleton, and a europium compound is a material for forming an emission center. The first raw material powder may further contain aluminum oxide and/or silicon oxide. Aluminum oxide and/or silicon oxide is a material for forming the skeleton of β-sialon.
Further, the first raw material powder may further contain β-sialon. β-sialon is an aggregate or core material.
The form of each of the above-mentioned components contained in the first raw material powder is not particularly limited, but it is preferable that all are in powder form.

The europium compound is not particularly limited, but examples thereof include an oxide containing europium, a hydroxide containing europium, a nitride containing europium, an oxynitride containing europium, and a halide containing europium. These may be used alone or in combination of two or more. Among these, europium oxide, europium nitride and europium fluoride are preferably used alone, and more preferably europium oxide is used alone.

The europium compound is separately added before firing in a plurality of firing steps. Specifically, the europium compound is added before the firing in the first firing step and the second firing step, respectively.
Here, in the method for producing the β-sialon phosphor according to the present embodiment, the second firing step is controlled so that the content of Eu element in the first fired powder obtained in the first firing step is reduced. Thereby, the brightness of the obtained β-sialon phosphor can be improved.
The reason for this is not clear, but it is considered that Eu, which does not contribute to the improvement of the brightness of the β-sialon phosphor, can be effectively removed as a different phase component in the second firing step.

In each firing step, europium is divided into those which form a solid solution in β-sialon, those which volatilize, and those which remain as a different phase component. The heterophasic component containing europium can be removed by acid treatment or the like, but if it is produced in an excessively large amount, an insoluble component is produced by the acid treatment and the brightness is reduced. Further, as long as it is a different phase that does not absorb extra light, it may remain, or europium may be contained in this different phase. When the europium compound is added before firing in a plurality of firing steps, a β-sialon phosphor raw material other than the europium compound may be added together with the europium compound.

In the method for producing the β-sialon phosphor according to the present embodiment, when the total amount of the first baked powder and the second europium compound is 100% by mass, Eu that does not contribute to the brightness improvement of the β-sialon phosphor is further effective. From the viewpoint of further improving the brightness of the resulting β-sialon phosphor, the proportion of the second europium compound is preferably 1.0% by mass or more, more preferably 2.0% by mass or more, and further preferably Is 3.0% by mass or more, and the amount of the second europium compound is preferably from the viewpoint of reducing the amount of insoluble heterophase components generated by acid treatment and further improving the brightness of the obtained β-sialon phosphor. It is 18.0 mass% or less, more preferably 17.0 mass% or less, and further preferably 15.0 mass% or less.
Further, in the method for producing the β-sialon phosphor according to the present embodiment, when the proportion of the second europium compound is within the above range, Eu that does not contribute to the brightness improvement of the β-sialon phosphor is more effectively removed. In addition, since it is possible to suppress the generation of an insoluble heterophasic component by the acid treatment, it is possible to simplify the manufacturing process for removing the heterophasic component, and as a result, it is possible to shorten the manufacturing time of the β-sialon phosphor.

The total amount of europium contained in the first raw material powder and the second raw material powder is not particularly limited, but it is preferably 3 times or more the amount of europium solid-dissolved in the finally obtained β-sialon phosphor, and 4 times. The above is more preferable.
The total amount of europium contained in the first raw material powder and the second raw material powder is not particularly limited, but it is preferably 25 times or less of the amount of europium solid-dissolved in the finally obtained β-sialon phosphor. It is more preferably 22 times or less. This makes it possible to reduce the amount of insoluble heterophase components generated by the acid treatment, and further improve the brightness of the obtained β-sialon phosphor.

The amount of europium contained in the first raw material powder is not particularly limited, but it is preferably larger than the amount of europium solid-dissolved in the finally obtained β-sialon phosphor.
The amount of europium contained in the first raw material powder is preferably 3 times or less than the amount of europium solid-dissolved in the finally obtained β-sialon phosphor. This makes it possible to reduce the amount of insoluble heterophase components generated by the acid treatment, and further improve the brightness of the obtained β-sialon phosphor.

In each firing step, the raw material powder containing the europium compound is obtained by, for example, a method of dry mixing, a method of wet mixing in an inert solvent that does not substantially react with each component of the raw material, and then removing the solvent. be able to. The mixing device is not particularly limited, but, for example, a V-type mixer, a rocking mixer, a ball mill, a vibration mill or the like can be used.

The firing temperature in each firing step is not particularly limited, but is preferably in the range of 1800°C or higher and 2100°C or lower.
When the firing temperature is at least the above lower limit value, the grain growth of the β-sialon phosphor proceeds more effectively, so that the light absorption rate, the internal quantum efficiency, and the external quantum efficiency can be further improved.
When the firing temperature is at most the above upper limit, the decomposition of the β-sialon phosphor can be further suppressed, so that the light absorption rate, the internal quantum efficiency, and the external quantum efficiency can be further improved.
Other conditions such as temperature raising time, temperature raising rate, heating holding time and pressure in each firing step are not particularly limited, and may be appropriately adjusted according to the raw material used. Typically, the heating and holding time is preferably 3 to 30 hours, and the pressure is preferably 0.6 to 10 MPa.

In each firing step, as a method for firing the mixture, for example, a method in which a container made of a material (for example, boron nitride) that does not react with the mixture during firing is filled with the mixture and heated in a nitrogen atmosphere can be used. By using such a method, a β-sialon phosphor can be obtained by promoting a crystal growth reaction or a solid solution reaction.

The first calcined powder and the second calcined powder are granular or massive sintered bodies. The granular or lump-shaped sintered body can be made into a β-sialon phosphor having a predetermined size by using treatments such as crushing, crushing, and classifying alone or in combination.
As a specific treatment method, for example, a method of pulverizing the sintered body to a predetermined particle size by using a general pulverizer such as a ball mill, a vibration mill, or a jet mill can be mentioned. However, it should be noted that excessive pulverization not only produces fine particles that easily scatter light, but also causes crystal defects on the particle surface, which may cause a decrease in the emission efficiency of β-sialon. Note that this treatment may be performed after the acid treatment or alkali treatment described later.

From the viewpoint of more suitably using the β-sialon phosphor as an LED phosphor, the β-sialon phosphor has an average particle diameter of preferably 5 μm or more, more preferably 10 μm or more. Further, from the viewpoint of further suppressing the color variation of the LED manufactured using the β-sialon phosphor, the β-sialon phosphor preferably has an average particle diameter of 40 μm or less.
Here, in the present embodiment, the “average particle diameter” means a 50% diameter in a volume-based integrated fraction by a laser diffraction scattering method according to JIS R1629:1997.

In the method for manufacturing a β-sialon phosphor according to the present embodiment, after the second firing step, an annealing step of heating the second firing powder at a temperature lower than the firing temperature of the second firing step to obtain an annealed product is further performed. May be included.
This annealing step is performed using a rare gas, an inert gas such as nitrogen gas, a hydrogen gas, a carbon monoxide gas, a hydrocarbon gas, a reducing gas such as an ammonia gas, or a mixed gas thereof, or a gas other than pure nitrogen such as vacuum. It is preferably performed in a non-oxidizing atmosphere, and particularly preferably in a hydrogen gas atmosphere or an argon atmosphere.
Further, the annealing step may be performed under either atmospheric pressure or pressure. The heat treatment temperature in the annealing step is not particularly limited, but is preferably 1200 to 1700°C, more preferably 1300°C to 1600°C.
By performing this annealing step, the luminous efficiency of the β-sialon phosphor can be further improved. Further, the rearrangement of the elements removes strains and defects, so that the transparency can be improved. In addition, in the annealing process, a different phase may occur, which can be removed by an acid treatment described later.

In addition, before the annealing step, a compound of the elements forming the β-sialon phosphor may be added and mixed. The compound to be added is not particularly limited, but examples thereof include oxides, nitrides, oxynitrides, fluorides and chlorides of each element. In particular, by adding silica, aluminum oxide, europium oxide, europium fluoride, or the like to each heat-treated product, the brightness of the β-sialon phosphor can be further improved. However, as for the raw material to be added, it is desirable that the residue which does not form a solid solution can be removed by acid treatment or alkali treatment after the annealing step.

The method for producing the β-sialon phosphor according to the present embodiment preferably further comprises a step of subjecting the second baked powder or the annealed product of the second baked powder to acid treatment, alkali treatment and/or fluorine treatment.
Here, the acid treatment or the alkali treatment is, for example, a treatment of bringing an acidic or alkaline liquid into contact with the second baked powder or an annealed product of the second baked powder. The fluorine treatment is, for example, a step of bringing a gas containing fluorine into contact with the second baked powder or an annealed product of the second baked powder.
By carrying out such a step, the heterophasic component (light emission inhibiting factor) generated in the firing step or the annealing step can be dissolved and removed. Therefore, the light absorption rate, the internal quantum efficiency and the external quantum of the β-sialon phosphor can be reduced. The efficiency can be further improved.
As the acidic liquid, for example, an aqueous solution containing one or more acids selected from hydrofluoric acid, sulfuric acid, phosphoric acid, hydrochloric acid, and nitric acid can be used. As the alkaline liquid, for example, an aqueous solution containing one or more kinds of alkali selected from potassium hydroxide, ammonia water, and sodium hydroxide can be used, more preferably an acidic aqueous solution, and particularly preferably fluorinated. It is a mixed aqueous solution of hydrochloric acid and nitric acid.

The treatment method using an acidic or alkaline liquid is not particularly limited, but the second fired powder or an annealed product of the second fired powder is dispersed in an aqueous solution containing the above-mentioned acid or alkali, and several minutes to several hours are passed. (For example, 10 minutes to 6 hours), the reaction can be performed by stirring. After this treatment, it is desirable to separate substances other than the β-sialon phosphor by filtration and wash the substances attached to the β-sialon phosphor with water.

The β-sialon phosphor produced as described above can be preferably used as a material for a phosphor layer in a light emitting element. The light emitting element can be applied to a light source such as a backlight light source of a display and a lighting device. The light emitting element is not particularly limited, but includes an LED and a phosphor layer laminated on the light emitting surface side of the LED. As the LED, an ultraviolet LED or a blue LED that emits light having a wavelength of 300 to 500 nm, and particularly a blue LED that emits light having a wavelength of 440 to 480 nm can be used. In particular, the β-sialon phosphor obtained by the manufacturing method according to the present embodiment is excited by a wide range of wavelengths from ultraviolet to blue light, and exhibits high-intensity green light emission. Therefore, white light using blue light or ultraviolet light as a light source. It can be suitably used as a phosphor for an LED.

The embodiments of the present invention have been described above, but these are examples of the present invention, and various configurations other than the above can be adopted.
It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within the scope of achieving the object of the present invention are included in the present invention.

Hereinafter, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

(Example 1)
Using a V-type mixer (S-3 manufactured by Tsutsui Rikagaku Kikai Co., Ltd.), 95.80 mass% of α-type silicon nitride powder (SN-E10 grade, oxygen content 1.0 mass%) manufactured by Ube Industries, Tokuyama Aluminum nitride powder (F grade, oxygen content 0.8% by mass) 2.74% by mass, aluminum oxide powder (TM-DAR grade) 0.56% by mass manufactured by Daimei Chemical Co., Ltd. and Shin-Etsu Chemical Co., Ltd. Was mixed with 0.90% by mass of the europium oxide powder (RU grade), and then the obtained mixture was passed through a sieve having an opening of 250 μm to remove agglomerates to obtain a first raw material mixed powder. The blending ratio (referred to as the first blending composition (mass %)) here is Si/Al except for europium oxide in the general formula of β-sialon: Si _6-Z Al _Z O _Z N _8-Z . It is designed so that Z=0.22 calculated from the ratio.

200 g of the obtained raw material powder having the first composition was filled in a cylindrical boron nitride container having an inner diameter of 10 cm and a height of 10 cm and having a lid, and was heated in an electric furnace of a carbon heater in a pressurized nitrogen atmosphere of 0.8 MPa at 1950. A heat treatment (first firing step) was performed at 10° C. for 10 hours. The heat-treated powder was pulverized by a supersonic jet pulverizer (PJM-80SP, manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and then the obtained pulverized product was passed through a nylon sieve having an opening of 45 μm, One calcined powder was obtained.

The Eu content in the obtained first baked powder was measured by ICP emission spectroscopy. As a result, the Eu content in the first baked powder was 0.77 mass %.

The obtained first baked powder and Europium oxide powder (RU grade) manufactured by Shin-Etsu Chemical Co., Ltd. were mixed at a compounding ratio of 97:3 (referred to as a second compounding composition (mass %)), and V-shaped. The first baked powder and europium oxide powder were mixed using a mixer (S-3 manufactured by Tsutsui Rikagaku Kikai Co., Ltd.). Next, the obtained mixture was passed through a nylon sieve having openings of 250 μm to remove agglomerates to obtain a second raw material mixed powder.

200 g of the obtained raw material powder having the second blended composition was filled in a cylindrical boron nitride container with an inner diameter of 10 cm and a height of 10 cm and having a lid, and was placed in a carbon heater electric furnace in a pressurized nitrogen atmosphere of 0.8 MPa at 2020. A heat treatment (second firing step) was performed at 12° C. for 12 hours. The heat-treated powder was pulverized by a supersonic jet pulverizer (PJM-80SP, manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and then the obtained pulverized product was passed through a nylon sieve having an opening of 45 μm, Two calcined powders were obtained. The passing rate through the sieve was 92%.

20 g of the obtained second baked powder was filled in a cylindrical boron nitride container with a lid having an inner diameter of 5 cm and a height of 3.5 cm, and annealed at 1500° C. for 8 hours in an argon atmosphere in a carbon heater electric furnace. Processed. The annealed powder was subjected to an acid treatment of immersion in a 1:1 mixed acid of 50% hydrofluoric acid and 70% nitric acid at 75° C. for 30 minutes. Precipitate the powder after the acid treatment as it is, and repeat decantation to remove the supernatant and fine powder until the pH of the solution is 5 or more and the supernatant becomes transparent, and the finally obtained precipitate is filtered and dried, The phosphor powder of Example 1 was obtained.
As a result of powder X-ray diffraction measurement, it was found that the crystal phase present was a β-sialon single phase, and a β-sialon phosphor was obtained. The Eu content measured by ICP emission spectroscopy was 0.72% by mass.
Here, Table 1 shows the first composition and the second composition in Example 1.

<Evaluation of fluorescent properties>
The fluorescence characteristics of the β-sialon phosphor were evaluated by the peak intensity and peak wavelength measured by the following method.
A spectrofluorometer (F-7000 manufactured by Hitachi High-Technologies Corporation) calibrated by the Rhodamine B method and a standard light source was used as the device. The obtained phosphor powder was filled in a dedicated solid sample holder, and then, using a spectrofluorometer, a fluorescence spectrum when irradiated with excitation light having a wavelength of 455 nm was measured, and from the obtained fluorescence spectrum, The peak intensity and peak wavelength were determined. The obtained results are shown in Table 2.
The unit is an arbitrary unit because the peak intensity changes depending on the measuring device and conditions, and is measured under the same conditions in each Example and Comparative Example, and the β-sialon phosphors of each Example and Comparative Example are continuously measured. Then, a comparison was made. Table 2 shows the peak intensity of the phosphor when the peak intensity of the β-sialon phosphor of Example 5 is 100%.

(Examples 2 to 6)
Β-Sialon phosphor powders were obtained in the same manner as in Example 1 except that the second composition was changed to the composition ratio shown in Table 1. As a result of powder X-ray diffraction measurement performed on the obtained β-sialon phosphor, the crystal phase present in each was a β-sialon single phase.
Table 2 shows the results of Eu content and fluorescence characteristics measured by ICP emission spectroscopy.

(Comparative Example 1)
A β-sialon phosphor powder was obtained in the same manner as in Example 1 except that the first blending composition was changed to the blending ratio shown in Table 1 and the step corresponding to the second firing step in Example 1 was not performed. It was It was visually confirmed that the first fired powder contained a large amount of red heterophase.
As a result of powder X-ray diffraction measurement, a diffraction peak presumed to be derived from a heterogeneous phase whose attribution was unknown was observed together with the β-sialon crystal phase.
Table 2 shows the results of Eu content and fluorescence characteristics measured by ICP emission spectroscopy. Compared with Examples 1 to 6, the Eu content was remarkably high, but this is because the above-mentioned heterophasic components remained after the acid treatment, and it was found that the peak intensity was also remarkably reduced.

From Table 2, it was found that the β-sialon phosphors of Examples 1 to 6 have higher fluorescence peak intensity than the β-sialon phosphor of Comparative Example 1 and are high-luminance β-sialon phosphors. ..

[1]
A method for producing a β-sialon phosphor having europium as a solid solution,
A first firing step of firing a first raw material powder containing a first europium compound to obtain a first fired powder containing β-sialon particles,
A second firing step of reducing the content of the Eu element in the first fired powder by firing the obtained second fired powder containing the first fired powder and the second europium compound;
Only including,
When the total of the first baked powder and the second europium compound is 100% by mass,
A method for producing a β-sialon phosphor, wherein the proportion of the second europium compound is 1.0% by mass or more and 18.0% by mass or less .
[ 2 ]
In the method for producing a β-sialon phosphor described in [1 ] above,
When the total of the first baked powder and the second europium compound is 100% by mass,
A method for producing a β-sialon phosphor, wherein the proportion of the second europium compound is 2.0% by mass or more and 17.0% by mass or less.
[ 3 ]
In the method for producing a β-sialon phosphor according to the above [1] or [2] ,
The method for producing a β-sialon phosphor, wherein the second europium compound contains europium oxide.
[ 4 ]
In the method for producing a β-sialon phosphor according to any one of the above [1] to [ 3 ],
Production of β-sialon phosphor in which the total amount of europium contained in the first raw material powder and the second raw material powder is 3 times or more the amount of europium solid-dissolved in the finally obtained β-sialon phosphor. Method.
[ 5 ]
In the method for producing a β-sialon phosphor according to any one of the above [1] to [ 4 ],
A method for producing a β-sialon phosphor, wherein the amount of europium contained in the first raw material powder is larger than the amount of europium solid-dissolved in the finally obtained β-sialon phosphor.
[ 6 ]
In the method for producing a β-sialon phosphor according to any one of [1] to [ 5 ] above,
A method for producing a β-sialon phosphor, wherein the firing temperature in the second firing step is 1800° C. or higher and 2100° C. or lower.
[ 7 ]
In the method for producing a β-sialon phosphor according to any one of [1] to [ 6 ] above,
A method for producing a β-sialon phosphor, wherein the firing temperature in the first firing step is 1800° C. or higher and 2100° C. or lower.
[ 8 ]
In the method for producing a β-sialon phosphor according to any one of [1] to [ 7 ] above,
The method for producing a β-sialon phosphor, further comprising an annealing step of heating at a temperature lower than the firing temperature of the second firing step after the second firing step.
[ 9 ]
In the method for producing a β-sialon phosphor according to any one of [1] to [ 8 ] above,
The method for producing a β-sialon phosphor further comprising a step of subjecting the second baked powder obtained in the second baking step or an annealed product of the second baked powder to an acid treatment, an alkali treatment and/or a fluorine treatment.

The embodiments of the present invention have been described above, but these are examples of the present invention, and various configurations other than the above can be adopted.
It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within the scope of achieving the object of the present invention are included in the present invention.
Hereinafter, an example of the reference mode of the present invention will be shown.
[1]
A method for producing a β-sialon phosphor having europium as a solid solution,
A first firing step of firing a first raw material powder containing a first europium compound to obtain a first fired powder containing β-sialon particles,
A second firing step of reducing the content of the Eu element in the first fired powder by firing the obtained second fired powder containing the first fired powder and the second europium compound;
A method for producing a β-sialon phosphor containing:
[2]
In the method for producing a β-sialon phosphor according to the above [1],
When the total of the first baked powder and the second europium compound is 100% by mass,
A method for producing a β-sialon phosphor, wherein the ratio of the second europium compound is 1.0% by mass or more and 18.0% by mass or less.
[3]
In the method for producing a β-sialon phosphor according to the above [1] or [2],
When the total of the first baked powder and the second europium compound is 100% by mass,
A method for producing a β-sialon phosphor, wherein the proportion of the second europium compound is 2.0% by mass or more and 17.0% by mass or less.
[4]
In the method for producing a β-sialon phosphor according to any one of [1] to [3] above,
The method for producing a β-sialon phosphor, wherein the second europium compound contains europium oxide.
[5]
In the method for producing a β-sialon phosphor according to any one of [1] to [4] above,
Production of β-sialon phosphor in which the total amount of europium contained in the first raw material powder and the second raw material powder is 3 times or more the amount of europium solid-dissolved in the finally obtained β-sialon phosphor. Method.
[6]
In the method for producing a β-sialon phosphor according to any one of [1] to [5] above,
A method for producing a β-sialon phosphor, wherein the amount of europium contained in the first raw material powder is larger than the amount of europium solid-dissolved in the finally obtained β-sialon phosphor.
[7]
In the method for producing a β-sialon phosphor according to any one of the above [1] to [6],
A method for producing a β-sialon phosphor, wherein the firing temperature in the second firing step is 1800° C. or higher and 2100° C. or lower.
[8]
In the method for producing a β-sialon phosphor according to any one of the above [1] to [7],
A method for producing a β-sialon phosphor, wherein the firing temperature in the first firing step is 1800° C. or higher and 2100° C. or lower.
[9]
In the method for producing a β-sialon phosphor according to any one of the above [1] to [8],
The method for producing a β-sialon phosphor, further comprising an annealing step of heating at a temperature lower than the firing temperature of the second firing step after the second firing step.
[10]
In the method for producing a β-sialon phosphor according to any one of [1] to [9] above,
The method for producing a β-sialon phosphor further comprising a step of subjecting the second baked powder obtained in the second baking step or an annealed product of the second baked powder to an acid treatment, an alkali treatment and/or a fluorine treatment.

Claims (10)

A method for producing a β-sialon phosphor having europium as a solid solution,
A first firing step of firing a first raw material powder containing a first europium compound to obtain a first fired powder containing β-sialon particles,
A second firing step of reducing the content of the Eu element in the first fired powder by firing the obtained second fired powder containing the first fired powder and the second europium compound,
A method for producing a β-sialon phosphor containing: The method for producing a β-sialon phosphor according to claim 1,
When the total of the first baked powder and the second europium compound is 100% by mass,
A method for producing a β-sialon phosphor, wherein the proportion of the second europium compound is 1.0% by mass or more and 18.0% by mass or less. The method for producing a β-sialon phosphor according to claim 1 or 2, wherein
When the total of the first baked powder and the second europium compound is 100% by mass,
A method for producing a β-sialon phosphor, wherein the proportion of the second europium compound is 2.0% by mass or more and 17.0% by mass or less. The method for producing a β-sialon phosphor according to any one of claims 1 to 3,
The method for producing a β-sialon phosphor, wherein the second europium compound contains europium oxide. The method for producing a β-sialon phosphor according to any one of claims 1 to 4,
Production of β-sialon phosphor in which the total amount of europium contained in the first raw material powder and the second raw material powder is 3 times or more the amount of europium solid-dissolved in the finally obtained β-sialon phosphor. Method. The method for producing a β-sialon phosphor according to any one of claims 1 to 5,
A method for producing a β-sialon phosphor, wherein the amount of europium contained in the first raw material powder is larger than the amount of europium solid-dissolved in the finally obtained β-sialon phosphor. The method for producing a β-sialon phosphor according to any one of claims 1 to 6,
The method for producing a β-sialon phosphor, wherein the firing temperature in the second firing step is 1800° C. or higher and 2100° C. or lower. The method for producing a β-sialon phosphor according to any one of claims 1 to 7,
The method for producing a β-sialon phosphor, wherein the firing temperature in the first firing step is 1800° C. or higher and 2100° C. or lower. The method for producing a β-sialon phosphor according to any one of claims 1 to 8,
The method for producing a β-sialon phosphor, further comprising an annealing step of heating at a temperature lower than the firing temperature of the second firing step after the second firing step. The method for producing a β-sialon phosphor according to any one of claims 1 to 9,
The method for producing a β-sialon phosphor further comprising a step of subjecting the second baked powder obtained in the second baking step or an annealed product of the second baked powder to an acid treatment, an alkali treatment and/or a fluorine treatment.