JP7295476B2 - Method for producing β-sialon phosphor - Google Patents

Description

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

By combining a light emitting diode (hereinafter referred to as "LED") as a light source and a phosphor that can be excited by the light from the light source to emit light with a different hue from the light source, light Light-emitting devices capable of emitting light of various colors have been developed according to the principle of color mixing. Among such phosphors, a phosphor containing β-sialon (hereinafter also referred to as “β-sialon phosphor”) is excited in a wide wavelength range from near-ultraviolet light to blue light, and has a wavelength of 520 nm or more and 560 nm or less. It is a green phosphor with an emission peak wavelength in the range.

The composition of the β-sialon phosphor is represented by, for example, Si _6-z Al _z O _z N _8-z :Eu (0<z≦4.2). The β-sialon phosphor contains silicon nitride (Si ₃ N ₄ ), aluminum nitride (AlN), aluminum oxide (Al ₂ O ₃ ), and europium oxide (Eu ₂ O ₃ ) as an activator at a predetermined molar ratio. By mixing and firing at around 2000° C., a fired product can be obtained. In order to increase the emission intensity, it has been proposed to perform heat treatment at a high temperature in two steps, or to use a β-sialon phosphor obtained by sintering a part of the raw material (for example, , see Patent Documents 1 and 2).

JP 2007-326981 A JP 2013-173868 A

A β-sialon phosphor is required to have a higher emission intensity. An object of one embodiment of the present invention is to provide a method for producing a β-sialon phosphor with excellent emission intensity.

A first aspect comprises preparing a composition containing silicon nitride containing aluminum, oxygen atoms and europium, heat-treating the composition, and contacting the heat-treated composition with a basic substance. and bringing the composition in contact with the basic substance into contact with an acidic liquid medium containing an acidic substance.

According to one embodiment of the present invention, it is possible to provide a method for producing a β-sialon phosphor with excellent emission intensity.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated based on embodiment and an Example. However, the embodiments shown below are examples of manufacturing methods and the like for embodying the technical idea of the present invention, and the present invention is not limited to the following. The relationship between the color name and chromaticity coordinates, the relationship between the wavelength range of light and the color name of monochromatic light, etc. conform to JIS Z8110. In this specification, the term "process" is not only an independent process, but even if it cannot be clearly distinguished from other processes, it is included in this term as long as the intended purpose of the process is achieved. . The content of each component in the composition means the total amount of the plurality of substances present in the composition unless otherwise specified when there are multiple substances corresponding to each component in the composition. The average particle diameter is the volume median diameter (Dm) and is measured by the pore electrical resistance method based on the Coulter principle. Specifically, the particle size distribution is measured using a particle size distribution analyzer (for example, Multisizer manufactured by Beckman Coulter), and the volume median diameter (Dm) is obtained as the particle size corresponding to 50% of the cumulative volume from the small diameter side. .

Method for producing β-sialon phosphor A method for producing a β-sialon phosphor comprises preparing a composition containing silicon nitride containing aluminum, oxygen atoms and europium (hereinafter also referred to as a “preparation step”), and Heat treatment (hereinafter also referred to as “first heat treatment step”), contacting the heat-treated composition with a basic substance (hereinafter also referred to as “base treatment step”), and contacting with the basic substance contacting the resulting composition with an acidic liquid medium containing an acidic substance (hereinafter also referred to as an "acid treatment step").

The composition itself prepared in the preparation step is, for example, β-sialon phosphor particles, and by heat-treating this, unstable phases such as low crystal parts contained in the phosphor particles are thermally decomposed into silicon. It is believed that thermal decomposition products are produced. Then, by bringing the heat-treated composition containing the pyrolyzate and the phosphor particles into contact with a basic substance, for example, the pyrolyzate reacts with the basic substance to produce an alkali metal silicate or the like. It is thought that it changes into a solubilized material with high translucency. It is considered that this can increase the emission intensity. These solubilized substances can be easily dissolved and removed by contact with an acidic liquid medium. Furthermore, the base treatment by contact with a basic substance is considered to damage the β-sialon phosphor particles less than the hydrofluoric acid-based acid treatment, and is presumed to tend to increase the emission intensity. be. In addition, by contacting with an acidic liquid medium subsequent to contacting with a basic substance, fine particles containing impurities that are considered to be generated in contact with a basic substance are removed, and it is thought that the emission intensity is further improved. . Impurities include, for example, compounds containing europium. Impurities may inhibit the emission of the β-sialon phosphor, and it is considered that the removal of these impurities can further improve the emission luminance.

(Preparation process)
In the preparation step, a composition containing silicon nitride containing aluminum, oxygen atoms and europium is prepared. The prepared composition is, for example, silicon nitride in which aluminum, oxygen atoms and europium are solid-dissolved, and has a composition represented by the following formula (I), for example.
Si6 _{- zAlzOzN8 - z} : Eu (I)
In the formula, z satisfies 0<z≦4.2.
The composition may be prepared, for example, by selecting a desired composition from commercially available products, or by preparing a desired composition by heat-treating a mixture containing desired raw materials according to a conventional method. good.

When the composition is produced in the preparation step, for example, a desired composition is obtained by heat-treating a mixture containing an aluminum compound, a europium compound, and silicon nitride (hereinafter also referred to as a “raw material mixture”).

The raw material mixture may contain at least one aluminum compound, at least one europium compound, and at least one silicon nitride. Examples of aluminum compounds include oxides, hydroxides, nitrides, oxynitrides, fluorides and chlorides containing aluminum. At least part of the aluminum compound may be replaced with an aluminum metal element or an aluminum alloy. Specific examples of the aluminum compound include aluminum nitride (AlN), aluminum oxide (Al ₂ O ₃ ), aluminum hydroxide (Al(OH) ₃ ), and the like. It is preferred to use seeds. The aluminum compounds may be used singly or in combination of two or more.

The average particle diameter of the aluminum compound used as the raw material is, for example, 0.01 μm or more and 20 μm or less, preferably 0.1 μm or more and 10 μm or less. The purity of the aluminum compound is, for example, 95% by weight or more, preferably 99% by weight or more.

Europium compounds include oxides, hydroxides, nitrides, oxynitrides, fluorides, chlorides and the like containing europium. At least part of the europium compound may be replaced with europium metal or a europium alloy. Specific examples of the europium compound include europium oxide (Eu ₂ O ₃ ), europium nitride (EuN), europium fluoride (EuF ₃ ), and the like, and at least one selected from the group consisting of these is used. is preferred. Europium compounds may be used alone or in combination of two or more.

The average particle diameter of the europium compound used as a raw material is, for example, 0.01 μm or more and 20 μm or less, preferably 0.1 μm or more and 10 μm or less. The purity of the europium compound is, for example, 95% by weight or more, preferably 99.5% by weight or more.

Silicon nitride is a silicon compound containing nitrogen atoms and silicon atoms, and may be silicon nitride containing oxygen atoms. When silicon nitride contains oxygen atoms, the oxygen atoms may be contained as silicon oxide or may be contained as silicon oxynitride. The content of oxygen atoms contained in silicon nitride is, for example, less than 2% by weight, and may be 1.5% by weight or less. The content of oxygen atoms is, for example, 0.3% by weight or more, and may be 0.4% by weight or more. The purity of silicon nitride is, for example, 95% by weight or more, preferably 99% by weight or more.

The average particle diameter of silicon nitride is, for example, 0.01 μm or more and 15 μm or less, preferably 0.1 μm or more and 5 μm or less.

The raw material mixture may be a mixture in which at least a portion of silicon nitride is replaced with other silicon compounds such as elemental silicon and silicon oxide. That is, the raw material mixture may contain silicon elemental substance, silicon compound such as silicon oxide in addition to silicon nitride, or may contain silicon elemental substance, silicon compound such as silicon oxide instead of silicon nitride. . Silicon compounds include silicon oxide, silicon oxynitride, silicates, and the like.

The mixing ratio of the aluminum compound, the europium compound and the silicon nitride in the raw material mixture is, for example, the molar ratio (Si: Al) of the silicon atoms and aluminum atoms contained in the raw material mixture is (6-z): z (0 < z ≤ 4.2), preferably 0.01<z<1.0. The molar ratio of the total molar amount of silicon atoms and aluminum atoms to europium atoms ((Si+Al):Eu) is, for example, 6:0.001 to 6:0.05, preferably 6:0.003 to 6: 0.02.

The raw material mixture may further contain a separately prepared β-sialon phosphor, if necessary. When the raw material mixture contains the β-sialon phosphor, its content can be, for example, 1% by weight or more and 50% by weight or less in the total amount of the raw material mixture.

The raw material mixture may further contain a flux such as a halide, if necessary. When the raw material mixture contains flux, the reaction between the raw materials is further accelerated, and the solid-phase reaction proceeds more uniformly, so that a phosphor with a large particle size and excellent luminous properties can be obtained. This is probably because, for example, the temperature of the heat treatment in the preparation step is approximately the same as or higher than the temperature at which the liquid phase of the halide, which is the flux, is generated. As the halide, chlorides, fluorides, etc. of rare earth metals, alkaline earth metals or alkali metals can be used. The flux can be added as a compound in such an amount that the elemental ratio of cations will give the composition of the object, or it can be added after adjusting the amount of each raw material so as to achieve the composition of the object. can also When the raw material mixture contains flux, its content in the raw material mixture is, for example, 20% by weight or less, preferably 10% by weight or less. Moreover, the content thereof is, for example, 0.1% by weight or more.

The raw material mixture is obtained by weighing the desired raw material compounds to the desired compounding ratio, and then mixing the raw materials using a mixing method using a ball mill or the like, a mixer such as a Henschel mixer or a V-type blender, or a mixing method using a mortar and pestle. It can be obtained by mixing compounds. Mixing can be performed by dry mixing, or by adding a solvent or the like and performing wet mixing.

The heat treatment temperature of the raw material mixture is, for example, 1850° C. or higher and 2100° C. or lower, preferably 1900° C. or higher and 2050° C. or lower, more preferably 1920° C. or higher and 2050° C. or lower, even more preferably 2000° C. or higher and 2050° C. or lower. By heat-treating at a temperature of 1850° C. or higher, the β-sialon phosphor is efficiently formed, Eu easily enters the crystal, and the desired β-sialon phosphor is obtained. Also, if the heat treatment temperature is 2100° C. or less, decomposition of the formed β-sialon phosphor tends to be suppressed.

The atmosphere in the heat treatment of the raw material mixture is preferably an atmosphere containing nitrogen gas, more preferably substantially a nitrogen gas atmosphere. When the atmosphere for the heat treatment of the raw material mixture contains nitrogen gas, it may contain other gases such as hydrogen, oxygen, and ammonia in addition to nitrogen gas. The content of nitrogen gas in the heat treatment atmosphere of the raw material mixture is, for example, 90% by volume or more, preferably 95% by volume or more.

The pressure in the heat treatment of the raw material mixture can be, for example, normal pressure to 200 MPa. From the viewpoint of suppressing decomposition of the generated β-sialon phosphor, the pressure is preferably higher, and the gauge pressure is preferably 0.1 MPa or more and 200 MPa or less, more preferably 0.6 MPa or more and 1.2 MPa or less. Within the above range, there are fewer restrictions on industrial equipment.

In the heat treatment of the raw material mixture, for example, the temperature is raised from room temperature to a predetermined temperature. The heating time is, for example, 1 hour or more and 48 hours or less, preferably 2 hours or more and 24 hours or less, and more preferably 3 hours or more and 20 hours or less. When the heating time is 1 hour or longer, the growth of the phosphor particles tends to proceed sufficiently, and Eu tends to easily enter the crystals of the phosphor particles.

In the heat treatment of the raw material mixture, a holding time at a predetermined temperature may be provided. The holding time is, for example, 1 hour or more and 48 hours or less, preferably 2 hours or more and 30 hours or less, and more preferably 3 hours or more and 20 hours or less.

The temperature-lowering time from the predetermined temperature to room temperature in the heat treatment of the raw material mixture is, for example, 0.1 hours or more and 20 hours or less, preferably 1 hour or more and 15 hours or less, and more preferably 3 hours or more and 12 hours or less. In addition, a holding time at an appropriately selected temperature may be provided while the temperature is lowered from a predetermined temperature to room temperature. This retention time is adjusted, for example, so that the emission intensity of the β-sialon phosphor is higher. The holding time at the predetermined temperature during the temperature drop is, for example, 0.1 hour or more and 20 hours or less, preferably 1 hour or more and 10 hours or less. The temperature during the holding time is, for example, 1000° C. or higher and lower than 1800° C., preferably 1200° C. or higher and 1700° C. or lower.

The heat treatment of the raw material mixture can be performed, for example, by placing the raw material mixture in a crucible made of boron nitride.

After the heat treatment of the raw material mixture, a granule sizing step may be included in which the composition obtained by the heat treatment is combined with treatments such as pulverization, pulverization and classification. A powder having a desired particle size can be obtained by the sizing process. Specifically, after coarsely pulverizing the composition, it can be pulverized to a predetermined particle size using a general pulverizer such as a ball mill, jet mill, or vibration mill. The final adjustment of the particle size can also be performed after the first heat treatment step, base treatment step, acid treatment step, etc., which will be described later.

(First heat treatment step)
In the first heat treatment step, the composition prepared in the preparation step is heat-treated to obtain a first heat-treated product. In the first heat treatment step, for example, it is believed that at least part of the amorphous unstable crystals present in the β-sialon phosphor can be decomposed. The atmosphere of the first heat treatment step is preferably a rare gas atmosphere or under reduced pressure, more preferably a rare gas atmosphere, from the viewpoint of increasing the emission intensity.

The rare gas atmosphere in the first heat treatment step may contain at least one of rare gases such as helium, neon, and argon, and preferably contains at least argon. The rare gas atmosphere may contain oxygen, hydrogen, nitrogen, etc. in addition to the rare gas. The rare gas content in the rare gas atmosphere is, for example, 95% by volume or more, preferably 99% by volume or more.

When the first heat treatment step is performed in a rare gas atmosphere, the pressure can be, for example, in the range of normal pressure to 1 MPa, preferably normal pressure to 0.2 MPa.

The first heat treatment step may be performed under reduced pressure lower than normal pressure, and is preferably performed in vacuum. When the heat treatment is performed in vacuum, the pressure is, for example, 10 kPa or less, preferably 1 kPa or less, and more preferably 100 Pa or less. Here, "under reduced pressure" or "in a vacuum" does not exclude the presence of gas. Gases that may be present include noble gases, nitrogen, hydrogen, oxygen, and the like.

The heat treatment temperature in the first heat treatment step is, for example, 1300° C. or higher and 1600° C. or lower, preferably 1350° C. or higher and 1500° C. or lower. The temperature in the first heat treatment step is preferably lower than the temperature at which the raw material mixture is heat treated. As a result, unstable crystalline phases, amorphous phases, and the like contained in the phosphor particles are more efficiently thermally decomposed, and more stable and highly crystalline phosphor particles are formed. The thermal decomposition products produced in the first heat treatment step include, for example, simple silicon, europium compounds, and the like, and these can be removed by the base treatment step, acid treatment step, etc. described later.

The heat treatment time in the first heat treatment step is, for example, 1 hour or more and 48 hours or less, preferably 2 hours or more and 20 hours or less. In the first heat treatment step, for example, the heat treatment is performed by raising the temperature from room temperature to a predetermined temperature. The heating time is, for example, 1 hour or more and 48 hours or less, preferably 2 hours or more and 24 hours or less, and more preferably 3 hours or more and 20 hours or less. A holding time at a predetermined temperature may be provided in the first heat treatment step. The holding time is, for example, 1 hour or more and 48 hours or less, preferably 2 hours or more and 30 hours or less, and more preferably 3 hours or more and 20 hours or less.

The cooling time from the predetermined temperature to room temperature in the first heat treatment step is, for example, 0.1 hours or more and 20 hours or less, preferably 1 hour or more and 15 hours or less, and more preferably 3 hours or more and 12 hours or less. In addition, a holding time at an appropriately selected temperature may be provided while the temperature is lowered from a predetermined temperature to room temperature. This retention time is adjusted, for example, so that the emission intensity of the β-sialon phosphor is higher. The holding time at the predetermined temperature during the temperature drop is, for example, 0.5 hours or more and 20 hours or less, preferably 1 hour or more and 10 hours or less. The temperature during the holding time is, for example, 800° C. or higher and lower than 1600° C., preferably 1000° C. or higher and 1400° C. or lower.

In the first heat treatment step, the composition prepared in the preparation step may be heat treated in the presence of a europium compound. In that case, the heat treatment is preferably performed in a rare gas atmosphere. By heat-treating the composition obtained in the preparation step in the presence of a europium compound in a rare gas atmosphere, a β-sialon phosphor having a higher emission intensity can be efficiently produced. For example, this can be considered as follows. When the first heat treatment step is performed in the presence of a europium compound in a noble gas atmosphere, at least a portion of the europium compound is reduced to produce a gaseous substance derived from the europium compound. It is believed that the contact of the gaseous substance with the composition prepared in the preparation step facilitates reduction of europium contained in the composition to a divalent state. It is also believed that gaseous substances derived from the europium compound in its reduced state are incorporated into the composition. A combination of these factors is considered to increase the emission intensity.

Examples of the europium compound used in the first heat treatment step include oxides, hydroxides, nitrides, oxynitrides, fluorides and chlorides containing europium. At least part of the europium compound may be replaced with europium metal or a europium alloy. Specific examples of the europium compound include europium oxide (Eu ₂ O ₃ ), europium nitride (EuN), europium fluoride (EuF ₃ ), etc. At least one selected from the group consisting of these is preferred. , and europium oxide are more preferred. Europium compounds may be used alone or in combination of two or more.

The average particle diameter of the europium compound used in the first heat treatment step is, for example, 0.01 μm or more and 20 μm or less, preferably 0.1 μm or more and 10 μm or less. The purity of the europium compound is, for example, 95% by weight or more, preferably 99.5% by weight or more.

When a europium compound is used in the first heat treatment step, the weight ratio of the europium compound to the composition (100% by weight) obtained in the preparation step is, for example, 0.01% by weight or more, preferably 0.05% by weight or more. , more preferably 0.1% by weight or more. The weight ratio is 50% by weight or less, preferably 20% by weight or less, more preferably 15% by weight or less, and even more preferably 10% by weight or less.

When a europium compound is used in the first heat treatment step, the heat treatment may be performed in a state in which a gaseous substance generated from the europium compound can come into contact with the composition obtained in the preparation step. For example, the composition obtained in the preparation step and the europium compound may be mixed and heat-treated in the same container, and the composition obtained in the preparation step and the europium compound may be mixed in the same or separate The composition obtained in the preparation step may be mixed with part of the europium compound and the remainder may be placed in the same or separate container and heat treated without being mixed. When mixing the composition obtained in the preparation step with the europium compound, it is preferable to mix them as uniformly as possible.

The method for producing a β-sialon phosphor may include, after the first heat treatment step, a step of crushing, pulverizing, or the like the obtained first heat-treated product. Crushing treatment, pulverizing treatment and the like can be performed by the methods described above.

(Base treatment step)
In the base treatment step, the heat-treated composition obtained in the first heat treatment step (first heat-treated product) is brought into contact with a basic substance to obtain a base-treated product. By contacting with a basic substance, the thermal decomposition products contained in the first heat-treated product, which may affect the light emission characteristics, react with the basic substance and change into compounds that have little effect on the light emission characteristics. , it is considered possible to increase the emission intensity.

Basic substances include alkali metal hydroxides such as LiOH, _NaOH , _KOH , _RbOH and CsOH; alkalis such as _Li2CO3 , _Na2CO3 , _{K2CO3 , Rb2CO3 and Cs2CO3} ; metal carbonates; hydroxides of Group 2 elements of the periodic table such as Mg(OH) ₂ , Ca(OH) ₂ , Sr(OH) ₂ and Ba(OH) ₂ ; ammonia (NH ₃ ); hydrazine; catechol (EDP); and quaternary ammonium compounds such as tetramethylammonium hydroxide and tetraethylammonium hydroxide. _The basic substance is preferably soluble in water, LiOH, NaOH, KOH, _RbOH , _CsOH , _Li2CO3 , _Na2CO3 , _K2CO3 , _{Rb2CO3 , Cs2CO3} , _ammonia (NH ₃ ) and at least one selected from the group consisting of tetramethylammonium hydroxide, and alkali metal hydroxides such as LiOH, NaOH, KOH, RbOH, CsOH, and ammonia (NH ₃ ) It is more preferable to contain at least one selected from the group consisting of, and it is particularly preferable to contain at least NaOH or KOH.

The amount of the basic substance to be brought into contact with the first heat-treated product can be appropriately selected according to the type of the basic substance. The weight ratio of the basic substance to the first heat-treated product is, for example, 0.5% by weight or more, preferably 1% by weight or more, more preferably 5% by weight or more, and even more preferably 8% by weight or more. The weight ratio is, for example, 200% by weight or less, preferably 100% by weight or less, and more preferably 80% by weight or less. When the weight ratio of the basic substance is 0.5% by weight or more, the reaction with the thermal decomposition product tends to proceed sufficiently. .

The atmosphere of the base treatment step may be, for example, an oxidizing atmosphere such as air, or an inert gas atmosphere such as nitrogen gas or argon gas. The inert gas concentration in the inert gas atmosphere is, for example, 90% by volume or more, preferably 95% by volume or more. The pressure in the atmosphere of the base treatment step is, for example, 10 Pa or more and 1 MPa or less, preferably 100 Pa or more and 0.2 MPa or less.

The temperature of the base treatment step is, for example, 50° C. or higher and 650° C. or lower, preferably 50° C. or higher and 500° C. or lower, and more preferably 70° C. or higher and 400° C. or lower. By setting the contact temperature to 50° C. or higher, the reactivity between the thermal decomposition products and the like contained in the first heat-treated product and the basic substance is improved, and the productivity tends to be further improved. Further, by setting the contact temperature to 650° C. or lower, there is a tendency to suppress adverse effects on the manufactured phosphor.

The base treatment step may include applying multiple temperature conditions. The base treatment step includes, for example, contacting the first heat-treated product with a basic substance at a first temperature (also referred to as "first thermal base treatment"), and performing a second temperature higher than the first temperature (also referred to as “second thermal base treatment”). By performing the first thermal base treatment and the second thermal base treatment, the reaction between the basic substance and the thermal decomposition products tends to proceed more efficiently. In addition, there is a tendency that adverse effects on phosphor particles can be suppressed. The first temperature is, for example, 50° C. or higher and 150° C. or lower, preferably 60° C. or higher and 140° C. or lower, and more preferably 60° C. or higher and 120° C. or lower. The second temperature is higher than the first temperature, and is, for example, 90° C. or higher and 650° C. or lower, preferably 120° C. or higher and 500° C. or lower, more preferably 150° C. or higher and 400° C. or lower.

The contact time in the base treatment step may be appropriately selected according to the type of basic substance, weight ratio, contact temperature, and the like. The contact time is, for example, 0.1 hours or more and 48 hours or less, preferably 0.5 hours or more and 20 hours or less. Further, when the base treatment step includes the first thermal base treatment and the second thermal base treatment, the treatment time of the first thermal base treatment is, for example, 0.1 hours or more and 48 hours or less, or 0.5 hours or more and 20 hours. The following are preferred. The treatment time of the second thermal base treatment is, for example, 0.1 hours or more and 24 hours or less, preferably 0.5 hours or more and 12 hours or less.

The method of contacting the first heat-treated product with the basic substance preferably includes mixing the first heat-treated product with a solution of the basic substance. By using the solution of the basic substance, the first heat-treated product and the basic substance can be reacted more uniformly. The solvent that constitutes the solution of the basic substance can be appropriately selected from commonly used solvents as long as the basic substance dissolves therein. Examples of solvents include water; alcohols such as methanol, ethanol and isopropanol; and amines such as ethanolamine, triethanolamine and ethylenediamine. Solvents may be used singly or in combination of two or more. Among them, the solvent preferably contains water.

The concentration of the basic substance solution can be appropriately selected according to the type of the basic substance, the solvent, and the like. The concentration of the basic substance solution can be, for example, 0.1% by weight or more and 80% by weight or less, preferably 1% by weight or more and 50% by weight or less.

The base treatment step preferably includes removing at least part of the solvent contained in the solution in addition to mixing the first heat-treated product and the solution of the basic substance. By removing at least part of the solvent, the reaction efficiency between the basic substance and the pyrolyzate tends to be further improved. When the solvent is removed from the mixture of the first heat-treated product and the solution of the basic substance, the solvent removal rate can be, for example, 1% by weight or more, preferably 10% by weight or more, and more preferably 20% by weight or more. Preferably, 50% by weight or more is more preferable.

Methods for removing the solvent include, for example, heat treatment, decompression treatment, and the like, and these may be used in combination. The method for removing the solvent may be any method as long as the basic substance in the solution is not easily removed together with the solvent, and preferably includes at least heat treatment. When the solvent is removed by heat treatment, the temperature is preferably the same as the first temperature.

The basic treatment step includes mixing the first heat-treated product and a solution of a basic substance, contacting the first heat-treated product and the basic substance at a first temperature (first thermal base treatment), and After the monothermal base treatment, contacting the first heat-treated product with a basic substance at a second temperature higher than the first temperature (second thermal base treatment), preferably including The treatment includes removing at least a portion of the solvent contained in the solution of the basic substance, and the second thermal base treatment comprises subjecting the solvent-removed mixture of the first heat treated product and the basic substance to a second temperature. More preferably, it includes heat treating. By removing at least part of the solvent at the first temperature and then heat-treating at the second temperature, the reaction between the pyrolyzate and the like contained in the first heat-treated product and the basic substance proceeds more uniformly and efficiently. tend to

The solvent removal time at the first temperature can be appropriately selected according to the desired solvent removal rate and the like. The solvent removal time at the first temperature is the same as the treatment time of the first thermal base treatment, and the heat treatment time at the second temperature is the same as the treatment time of the second thermal base treatment. Here, the atmosphere for solvent removal at the first temperature may be, for example, the air or an inert gas atmosphere. On the other hand, the atmosphere for heat treatment at the second temperature is preferably an inert gas atmosphere.

The base treatment step may include a step of crushing treatment, pulverization treatment, or the like of the obtained base treatment product. Crushing treatment, pulverizing treatment and the like can be performed by the methods described above.

The base treatment step may further include a washing step of washing the resulting base treated product with a liquid medium. Washing of the base-treated product can be carried out by, for example, immersing the base-treated product in a liquid medium, stirring if necessary, and then performing solid-liquid separation. Alternatively, the base-treated product may be held in a funnel or the like and washed by passing a liquid medium through it. Washing may be performed until the liquid medium that has undergone solid-liquid separation or the liquid medium that has passed through the base-treated material exhibits neutrality. Furthermore, after cleaning with a liquid medium, a drying treatment may be performed as necessary. By performing a washing step after the base treatment step and before the acid treatment step, at least part of the microparticles contained in the base treated product can be removed.

The liquid medium used in the washing step may contain water, and in addition to water, if necessary, may further contain a water-soluble organic solvent such as alcohol such as ethanol or isopropanol. Also, the liquid medium may be a neutral liquid medium. Further, the liquid medium may be substantially water. Being substantially water means that the content of unavoidably mixed impurities is, for example, less than 1% by weight or less than 0.01% by weight. The temperature of the liquid medium is, for example, 5° C. or higher and 95° C. or lower, preferably 25° C. or higher and 80° C. or lower. The washing time can be, for example, 0.01 hours or more and 48 hours or less, preferably 0.1 hours or more and 20 hours or less.

(Acid treatment step)
The method for producing a β-sialon phosphor includes contacting the base-treated product after the base treatment step with an acidic liquid medium containing an acidic substance to obtain an acid-treated product (also referred to as an “acid treatment step”). good. By bringing the base-treated product into contact with the acidic liquid medium, at least a portion of unnecessary substances such as alkali metal silicates contained in the base-treated product are removed. Also, at least a portion of the microparticles containing impurities generated by the base treatment is removed.

The acid treatment can be performed, for example, by immersing the base-treated product in an acidic liquid medium, stirring if necessary, and then separating the solid from the liquid. Alternatively, the base-treated product may be held in a funnel or the like and passed through a liquid medium. The temperature of the acidic liquid medium used for the acid treatment may be, for example, 5°C or higher and 95°C or lower, 20°C or higher and 80°C or lower, or 25°C or higher and 60°C or lower. The acid treatment time may be, for example, 0.01 to 48 hours, 0.1 to 20 hours, or 0.2 to 5 hours.

The acidic liquid medium may contain an acidic substance and water, and may further contain a water-soluble organic solvent as necessary. Acidic substances include hydrogen chloride, nitric acid, sulfuric acid, etc., and preferably contain at least one selected from the group consisting of these. The content of the acidic substance in the acidic liquid medium is, for example, 0.1% by weight or more and 35% by weight or less, and may be 0.1% by weight or more and 18% by weight or less, or 0.1% by weight or more and 10% by weight or less. .

The amount of the acidic liquid medium used for the acid treatment may be, for example, 100% by weight or more and 1000% by weight or less, or 120% by weight or more and 500% by weight or less, or 150% by weight or less and 300% by weight or less with respect to the base-treated product. you can

The acid treatment step may further include a washing step of washing the obtained acid treated product with a liquid medium. Washing of the acid-treated product can be performed, for example, by immersing the acid-treated product in a liquid medium, stirring if necessary, and then separating the solid from the liquid. Alternatively, the acid-treated product may be held in a funnel or the like and washed by passing a liquid medium through it. Washing may be performed until the liquid medium that has undergone solid-liquid separation or the liquid medium that has passed through the acid-treated material exhibits neutrality. The details of the liquid medium used in the washing step of the acid treatment step are the same as those of the liquid medium used in the washing step of the base treatment step.

After washing with the liquid medium, a drying step may be performed as necessary. The drying step can be carried out by, for example, hot air drying, steam dryer, or the like. The drying temperature may be, for example, 60° C. or higher and 300° C. or lower, or 80° C. or higher and 150° C. or lower. The drying time may be, for example, 5 hours or more and 50 hours or less, 8 hours or more and 30 hours or less, or 10 hours or more and 25 hours or less.

The β-sialon phosphor obtained after the acid treatment step has an improved emission luminance compared to the composition before the acid treatment step. The relative luminance of the β-sialon phosphor obtained after the acid treatment process with respect to the emission luminance of the composition before the acid treatment process may be, for example, 100.5% or more or 101% or more, and for example, 110% or less or 105% or less. can be

The β-sialon phosphor obtained after the acid treatment process tends to have a larger volume median diameter (Dm) than the composition before the acid treatment process. The ratio of the volume median diameter of the β-sialon phosphor obtained after the acid treatment process to the volume median diameter of the composition before the acid treatment process may be, for example, 1.01 or more or 1.02 or more, or for example, 1.15. or less or 1.10 or less.

The β-sialon phosphor obtained after the acid treatment process tends to have a smaller specific surface area than the composition before the acid treatment process. The ratio of the specific surface area of the composition before the acid treatment process to the specific surface area of the β-sialon phosphor obtained after the acid treatment process may be, for example, 1.01 or more. The specific surface area is measured by a one-point method using nitrogen gas as an adsorption gas based on the BET method.

(Second heat treatment step)
The method for producing a β-sialon phosphor includes, prior to the first heat treatment step, strongly pulverizing the composition prepared in the preparation step and heat-treating it in a nitrogen atmosphere (also referred to as the “second heat treatment step”). good too. By including the second heat treatment step, a β-sialon phosphor having a higher emission intensity can be obtained. The reason why the emission intensity increases by including the second heat treatment step is, for example, that the crystallinity is improved, and the particles with insufficient crystal growth contained in the composition in the preparation step are incorporated into large particles, and the particles are more Growing up, etc.

The specific surface area of the strongly pulverized material in the second heat treatment step is, for example, 0.20 m ² /g or more, preferably 0.25 m ² /g or more, more preferably 0.28 m ² /g or more, and still more preferably 0 .29 m ² /g or more. By pulverizing the composition so that the specific surface area becomes, for example, 0.20 m ² /g or more, and then performing heat treatment again after pulverization, it is possible to obtain a β-sialon phosphor having a high relative emission intensity and excellent emission luminance. can. For example, it can be considered that the crystals are rearranged and the activating element is easily taken into the crystals when the crystals are rearranged.

The strong pulverization in the second heat treatment step can be performed using a dry pulverizer such as a ball mill, vibration mill, hammer mill, roll mill, and jet mill. The composition prepared in the preparation step may be powder aggregates in which powders are aggregated together. In this case, the resulting powder aggregate composition is pulverized using a mortar and pestle or the like to an average particle size of about 10 μm, specifically, an average particle size of more than 10 μm and less than 100 μm. Alternatively, it is preferable to perform coarse pulverization and then pulverize using the above-mentioned dry pulverizer or the like so as to have a predetermined specific surface area. Here, the average particle size of the composition is measured based on the air permeation method using a Fisher Sub-Sieve Sizer.

The heat treatment temperature in the second heat treatment step is, for example, 1800°C or higher and 2100°C or lower, preferably 1850°C or higher and 2040°C or lower, and more preferably 1900°C or higher and lower than 2040°C.

The atmosphere of the second heat treatment step is a nitrogen atmosphere containing at least nitrogen gas, preferably a nitrogen atmosphere substantially consisting of nitrogen gas. The nitrogen atmosphere in the second heat treatment step may contain other gases such as hydrogen, oxygen, and ammonia in addition to nitrogen gas. The nitrogen gas content in the nitrogen atmosphere in the second heat treatment step is, for example, 90% by volume or more, preferably 95% by volume or more.

The pressure in the second heat treatment step can be, for example, normal pressure to 200 MPa. From the viewpoint of suppressing the decomposition of the β-sialon phosphor to be produced, the higher the pressure, the better. Specifically, the gauge pressure is preferably 0.1 MPa or more and 200 MPa or less, more preferably 0.6 MPa or more and 1.2 MPa or less. Within the above range, there are fewer restrictions on industrial equipment.

In the second heat treatment step, for example, the heat treatment is performed by raising the temperature from room temperature to a predetermined temperature. The time required to raise the temperature is, for example, 1 hour or more and 48 hours or less, preferably 2 hours or more and 24 hours or less, and more preferably 3 hours or more and 20 hours or less. A holding time at a predetermined temperature may be provided in the second heat treatment step. The holding time is, for example, 1 hour or more and 48 hours or less, preferably 2 hours or more and 30 hours or less, and more preferably 3 hours or more and 20 hours or less.

The temperature drop time from the predetermined temperature to room temperature in the second heat treatment step is, for example, 0.1 hours or more and 20 hours or less, preferably 1 hour or more and 15 hours or less, and more preferably 3 hours or more and 12 hours or less. In addition, a holding time at an appropriately selected temperature may be provided while the temperature is lowered from a predetermined temperature to room temperature. This retention time is adjusted, for example, so that the emission intensity of the β-sialon phosphor is higher. The holding time at the predetermined temperature during the temperature drop is, for example, 0.1 hour or more and 20 hours or less, preferably 1 hour or more and 10 hours or less. The temperature during the holding time is, for example, 1000° C. or higher and lower than 1800° C., preferably 1200° C. or higher and 1700° C. or lower.

The second heat treatment step may be performed in the presence of a europium compound. Thereby, there is a tendency that the emission intensity can be further improved. The europium compound can be added, for example, when the composition is hard pulverized.

Examples of the europium compound used in the second heat treatment step include oxides, hydroxides, nitrides, oxynitrides, fluorides, chlorides, and the like containing europium. At least part of the europium compound may be replaced with europium metal or a europium alloy. Specific examples of the europium compound include europium oxide (Eu ₂ O ₃ ), europium nitride (EuN), europium fluoride (EuF ₃ ), etc. At least one selected from the group consisting of these is preferred. , and europium oxide are more preferred. Europium compounds may be used alone or in combination of two or more.

The average particle diameter of the europium compound used in the second heat treatment step is, for example, 0.01 μm or more and 20 μm or less, preferably 0.1 μm or more and 10 μm or less. The purity of the europium compound is, for example, 95% by weight or more, preferably 99.5% by weight or more.

When the europium compound is used in the second heat treatment step, the molar ratio of the europium compound to the composition (1 mol) obtained in the preparation step is, for example, 0.01 mol% or more, preferably 0.05 mol% or more, 0.08 mol % or more is more preferable. The molar ratio is 5 mol % or less, preferably 1 mol % or less, more preferably 0.5 mol % or less, and even more preferably 0.3 mol % or less.

When the method for producing a β-sialon phosphor includes the second heat treatment step, the composition after the second heat treatment is used in the first heat treatment step. Also, the method for producing a β-sialon phosphor may include the second heat treatment step a plurality of times. In that case, the composition after the last second heat treatment is used for the first heat treatment step.

(β-sialon phosphor)
The β-sialon phosphor of the present embodiment has high emission intensity due to being obtained by a specific manufacturing method. For example, the emission intensity can be increased by 5% or more, can be increased by 10% or more, and can be further increased by 50% or more, compared to the case of manufacturing without base treatment and acid treatment. The β-sialon phosphor of this embodiment has the composition represented by the above formula, but may contain a trace amount of alkali metal element. When the β-sialon phosphor contains an alkali metal element, the content is, for example, 0.1 ppm or more and 1000 ppm or less, preferably 0.1 ppm or more and 100 ppm or less.

The β-sialon phosphor according to the present embodiment absorbs light in the short wavelength region of ultraviolet to visible light, and has an emission peak wavelength on the longer wavelength side than the emission peak wavelength of excitation light. Light in the short wavelength region of visible light is mainly in the blue light region. Specifically, it is excited by light from an excitation light source having an emission peak wavelength in the wavelength range of 250 nm or more and 480 nm or less, and emits fluorescence having an emission peak wavelength in the wavelength range of 520 nm or more and 560 nm or less. By using an excitation light source having an emission peak wavelength in the wavelength range of 250 nm or more and 480 nm or less, the excitation spectrum of the β-sialon phosphor exhibits a relatively high intensity in the wavelength range, so that the luminous efficiency of the β-sialon phosphor is increased. be able to. In particular, it is preferable to use an excitation light source having an emission peak wavelength of 350 nm or more and 480 nm or less, and more preferably an excitation light source having an emission peak wavelength of 420 nm or more and 470 nm or less.

Further, the β-sialon phosphor according to this embodiment has high crystallinity. For example, a glass body (amorphous) has an irregular structure and low crystallinity. , chromaticity unevenness, and the like. On the other hand, the β-sialon phosphor according to the present embodiment tends to be easy to manufacture and process because it is powder or granules at least partially having a highly crystalline structure. In addition, since the β-sialon phosphor can be easily and uniformly dispersed in an organic medium, it is possible to easily prepare luminescent plastics, polymer thin film materials, and the like. Specifically, the β-sialon phosphor has a structure in which, for example, 50% by weight or more, more preferably 80% by weight or more, is crystalline. This indicates the ratio of the crystalline phase having luminescent property, and if the crystalline phase is present in an amount of 50% by weight or more, practically usable luminescence can be obtained, which is preferable. Therefore, the more the crystal phase, the better the luminous efficiency. Thereby, the emission intensity can be increased and the processing can be facilitated.

As for the average particle diameter of the β-sialon phosphor according to the present embodiment, the volume median diameter (Dm) measured by the Coulter principle is, for example, 4 μm or more and 40 μm or less, preferably 8 μm or more and 30 μm or less. Also, the β-sialon phosphor preferably contains particles having this average particle size frequently. That is, the particle size distribution is preferably distributed in a narrow range. By constructing a light-emitting device using a β-sialon phosphor having a narrow half-value width of the particle size distribution, it is possible to suppress color unevenness and obtain a light-emitting device having a favorable color tone. Also, the larger the average particle size, the higher the light absorption rate and the luminous efficiency. In this way, the luminous efficiency of the light-emitting device is improved by including the phosphor having a large average particle diameter and optically excellent characteristics in the light-emitting device.

(Example 1)
Preparatory step Silicon nitride (Si ₃ N ₄ ) as a raw material compound, aluminum nitride (AlN), and europium oxide (Eu ₂ O ₃ ) were mixed with Si:Al:Eu=5.79:0.21:0.011. They were weighed and mixed to obtain a first raw material mixture so as to obtain a molar ratio. At that time, aluminum nitride and aluminum oxide (AlN:Al ₂ O ₃ ) were weighed and mixed in a molar ratio of 84:16. A crucible made of boron nitride was filled with this raw material mixture, and heat treatment was performed in a nitrogen atmosphere at a pressure of about 0.92 MPa (gauge pressure) at 2030° C. for 10 hours to obtain a composition containing a β-sialon phosphor.

Second heat treatment step The obtained composition is coarsely pulverized using a mortar and pestle, and then two types of silicon nitride balls with a diameter (Φ) of 20 mm and a diameter (Φ) of 25 mm and a porcelain pot are used. A ball mill was used to perform the first crushing treatment by strong crushing for 25 hours to obtain a crushed product. In the first pulverization step, 0.0015 mol of europium oxide (Eu ₂ O ₃ ) was added to 1 mol of the fired product, and pulverization was performed.

Next, the obtained pulverized material is filled in a crucible made of boron nitride, heated to 2000 ° C. for 10 hours under a nitrogen atmosphere at 0.92 Mpa (gauge pressure), held at 2000 ° C. for 10 hours, Then, while the temperature was lowered to room temperature, the first heat treatment was performed at a temperature of 1500° C. for a holding time of 5 hours to obtain a heat treated product. Next, the obtained heat-treated product is coarsely pulverized using a mortar and pestle, and then a ball mill using two types of silicon nitride balls with a diameter (Φ) of 20 mm and a diameter (Φ) of 25 mm and a porcelain pot is used. Then, for 25 hours, a second pulverization treatment by strong pulverization was performed to obtain a pulverized material. In the second pulverization step, 0.001 mol of europium oxide (Eu ₂ O ₃ ) was added to 1 mol of the heat-treated product, and pulverization was performed. Next, the obtained pulverized product was subjected to a second heat treatment under the same conditions as the first heat treatment in the second heat treatment step to obtain a heat treated product after the second heat treatment step.

First Heat Treatment Step The heat-treated product obtained after the second heat treatment step and europium oxide in an amount of 0.5% by weight with respect to the heat-treated product were weighed and mixed to obtain a mixture. The obtained mixture is subjected to heat treatment in an argon atmosphere at normal pressure at a temperature of 1400°C for 5 hours, and then during the cooling to room temperature at a temperature of 1100°C for a holding time of 5 hours, followed by pulverization and dispersion treatment. to obtain a first heat-treated product.

Base treatment step The obtained first heat-treated product is mixed with a basic solution containing 33% by weight of sodium hydroxide and 67% by weight of pure water with respect to the first heat-treated product, and treated at 130 ° C. for 20 hours in the atmosphere. to remove 70% by weight or more of water to obtain a base-treated product.

Washing Step The obtained base-treated product was stirred in 1000% by weight (10 times the amount) of pure water with respect to the base-treated product. Thereafter, pure water was exchanged several times for washing, and after solid-liquid separation, drying treatment was performed at 100° C. for 15 hours.

Acid treatment step Mix the base-treated product after the washing step with an aqueous solution of hydrogen chloride (concentration: 0.1 wt%) corresponding to 150% by weight (1.5 times the amount) of the base-treated product. Acid treatment was carried out by stirring for 0.5 hours. After that, solid-liquid separation was performed to obtain an acid-treated product.

Washing Step The obtained acid-treated product was stirred in 1000% by weight (10 times the amount) of pure water with respect to the acid-treated product. Thereafter, the pure water was exchanged several times for washing, and after solid-liquid separation, drying treatment was performed at 100° C. for 15 hours to obtain Phosphor 1 .

(Example 2)
Phosphor 2 was obtained by synthesizing under the same conditions as in Example 1 except that the concentration of the hydrogen chloride aqueous solution in the acid treatment step was changed to 0.5% by weight.

(Example 3)
Synthesis was carried out under the same conditions as in Example 1, except that the concentration of the aqueous hydrogen chloride solution in the acid treatment step was changed to 1% by weight, and Phosphor 3 was obtained.

(Example 4)
Phosphor 4 was obtained by synthesizing under the same conditions as in Example 1, except that the concentration of the hydrogen chloride aqueous solution in the acid treatment step was changed to 3% by weight.

(Example 5)
Synthesis was carried out under the same conditions as in Example 1, except that the concentration of the aqueous hydrogen chloride solution in the acid treatment step was changed to 5% by weight, and a phosphor 5 was obtained.

(Example 6)
Synthesis was carried out under the same conditions as in Example 1, except that the concentration of the aqueous hydrogen chloride solution in the acid treatment step was changed to 7% by weight, and a phosphor 6 was obtained.

(Example 7)
Synthesis was carried out under the same conditions as in Example 1, except that the concentration of the aqueous hydrogen chloride solution in the acid treatment step was changed to 18% by weight, and a phosphor 7 was obtained.

(Example 8)
Synthesis was carried out under the same conditions as in Example 1, except that the concentration of the aqueous hydrogen chloride solution in the acid treatment step was changed to 35% by weight, and a phosphor 8 was obtained.

(Example 9)
Synthesis was carried out under the same conditions as in Example 1, except that the aqueous hydrogen chloride solution in the acid treatment step was changed to an aqueous nitric acid solution having a concentration of 0.1% by weight, and a phosphor 9 was obtained.

(Example 10)
Synthesis was performed under the same conditions as in Example 1, except that the aqueous hydrogen chloride solution in the acid treatment step was changed to an aqueous nitric acid solution having a concentration of 3% by weight, and a phosphor 10 was obtained.

(Example 11)
A phosphor 11 was obtained by synthesizing under the same conditions as in Example 1, except that the aqueous hydrogen chloride solution in the acid treatment step was changed to an aqueous nitric acid solution having a concentration of 7% by weight.

(Example 12)
Synthesis was carried out under the same conditions as in Example 1, except that the aqueous hydrogen chloride solution in the acid treatment step was changed to an aqueous sulfuric acid solution having a concentration of 0.1% by weight, and a phosphor 12 was obtained.

(Example 13)
Phosphor 13 was obtained by synthesizing under the same conditions as in Example 1, except that the aqueous hydrogen chloride solution in the acid treatment step was changed to an aqueous sulfuric acid solution having a concentration of 7% by weight.

(Comparative example 1)
Synthesis was carried out under the same conditions as in Example 1, except that the acid treatment step and the washing treatment after the acid treatment step were not performed, and a phosphor C1 was obtained.

(Comparative example 2)
Synthesis was carried out under the same conditions as in Example 1, except that pure water was used in place of the aqueous hydrogen chloride solution in the acid treatment step and the washing treatment after the acid treatment step was not performed, to obtain phosphor C2.

<Evaluation>
The average particle diameter (Dm, median diameter) and standard deviation σlog of the obtained β-sialon phosphor were measured by a pore electrical resistance method (electrical detection zone method) based on the Coulter principle, using a particle size distribution analyzer (Beckman Coulter Co., Ltd.). It was measured using a Multisizer manufactured by Note that σlog was calculated based on the following formula.
σ log = (|log(D1/Dm)|+|log(D2/Dm)|)/2
Here, D1 is the particle diameter at which the cumulative value from the smallest particle is 15.86%, and D2 is the particle diameter at which the cumulative value from the largest particle is 15.86%. Also, the average particle size D was measured based on the air permeation method using a Fisher Sub-Sieve Sizer.

The luminescent properties of the phosphor were measured using a spectrofluorophotometer: QE-2000 (manufactured by Otsuka Electronics Co., Ltd.). Specifically, the emission spectrum is measured with the wavelength of the excitation light set to 450 nm, and the maximum peak of the obtained emission spectrum is calculated by relative emission intensity (%), chromaticity coordinates (x, y), Y value, emission peak wavelength ( nm) was obtained. Here, the relative emission intensity was calculated using the emission intensity of the phosphor C1 of Comparative Example 1 as a reference. Moreover, the emission peak wavelength was around 538 nm in all cases. The evaluation results are shown in Table 1 below.

The relative brightness was improved by performing the acid treatment step after the base treatment step.

Claims (18)

providing a composition comprising silicon nitride comprising aluminum, oxygen atoms and europium;
pulverizing the composition together with a europium compound to obtain a pulverized product;
second heat-treating the pulverized material in a nitrogen atmosphere to obtain a second heat-treated composition;
further subjecting the second heat-treated composition to a first heat treatment;
contacting the first heat-treated composition with a basic substance;
A method for producing a β-sialon phosphor, comprising contacting the composition contacted with the basic substance and an acidic liquid medium containing an acidic substance. 2. The production method according to claim 1, wherein the basic substance contains at least one selected from the group consisting of alkali metal hydroxides and ammonia. The manufacturing method according to claim 1 or 2, wherein the contact between the first heat-treated composition and the basic substance is performed at a temperature of 50°C or higher and 650°C or lower. from claim 1, wherein contacting the first heat-treated composition with the basic substance comprises conducting at a first temperature and conducting at a second temperature that is higher than the first temperature. 4. The manufacturing method according to any one of 3. 5. The production method according to any one of claims 1 to 4, wherein the acidic liquid medium comprises at least one acidic substance selected from the group consisting of hydrogen chloride, nitric acid and sulfuric acid, and water. 6. The production method according to any one of claims 1 to 5, wherein the acidic liquid medium has a content of the acidic substance of 0.1% by weight or more and 35% by weight or less. Contacting the first heat-treated composition with the basic substance includes mixing the first heat-treated composition with a solution of the basic substance and adding at least a portion of the solvent contained in the solution. 7. The manufacturing method according to any one of claims 1 to 6, comprising removing the . 8. The production method according to any one of claims 1 to 7, wherein the weight ratio of the basic substance to be brought into contact with respect to the heat-treated composition is 0.5% by weight or more. 9. The production method according to any one of claims 1 to 8, wherein the first heat treatment of the second heat-treated composition is performed in the presence of a europium compound. 10. The manufacturing method according to any one of claims 1 to 9, wherein the first heat treatment of the second heat-treated composition is performed at a temperature of 1300[deg.]C or higher and 1600[deg.]C or lower. 11. The method of any one of claims 1 to 10, wherein the first heat treatment of the second heat treated composition is performed in a noble gas atmosphere. 12. A method according to any one of the preceding claims, wherein preparing the composition comprises heat-treating a mixture comprising an aluminum compound, a europium compound and silicon nitride. The production method according to any one of claims 1 to 12, wherein the pulverized product has a specific surface area of 0.20 m2 ^/ g or more. 13. Claims 1 to 13, wherein the composition has a composition represented by the formula Si _6-z Al _z O _z N _8-z :Eu, where z satisfies 0<z≦4.2. The manufacturing method according to any one of. The manufacturing method according to any one of claims 1 to 14, wherein the heat treatment temperature of the second heat treatment is 1800°C or higher and 2100°C or lower. The production method according to any one of claims 1 to 15, wherein the pressure in the second heat treatment is 0.1 MPa or more and 200 MPa or less as gauge pressure. 2. From claim 1, wherein the europium compound pulverized together with the composition contains at least one selected from the group consisting of europium-containing oxides, hydroxides, nitrides, oxynitrides, fluorides and chlorides. 17. The manufacturing method according to any one of 16. 18. The production method according to any one of claims 1 to 17, wherein the molar ratio of the europium compound to the composition in the pulverized product is 0.01 mol% or more and 5 mol% or less.