JP6784982B2 - Method for producing inorganic compounds - Google Patents

Description

The present invention relates to a method for producing an inorganic compound. In the following, a fluorescent substance will be described as an example of the inorganic compound, but the purpose is not limited to this.

Conventionally, a light emitting element composed of an LED (Light Emitting Mode) and a phosphor excited by receiving the light of the light emitting element are provided, and white light is emitted by mixing the color emitted by the light emitting element and the color emitted by the phosphor. Light emitting devices that emit light are known. Specifically, a combination of a near-ultraviolet LED or a purple LED and a red, green, or blue phosphor, a combination of a blue LED and a yellow phosphor, and the like are known. For example, Patent Document 1 discloses a white light emitting diode in which a nitride red phosphor is contained in a resin such as an epoxy resin and coated on a chip constituting a light emitting diode light source, and Patent Document 2 discloses blue light. A phosphor material which is a polycrystal having a property of absorbing and emitting yellow fluorescence, wherein the polycrystal is a YAG crystal is disclosed.

For example, as a method for producing a YAG phosphor, a method of mixing raw material powders Y ₂ O ₃ , Al ₂ O ₃ and CeO ₂ by ball milling and firing at a high temperature of 1600 ° C. or higher can be mentioned. As a means for lowering the firing temperature, there is a method of adding a sintering aid such as BaF ₂ to promote the reaction through a solid phase-liquid phase reaction, whereby the firing temperature can be lowered to about 1500 ° C. Grain growth can also be promoted (Non-Patent Document 1). However, even if a sintering aid is used, it is necessary to bake at a thousand and several hundred degrees Celsius, which requires high temperature equipment and increases the cost. Further, when firing at a high temperature, the raw material reacts with the crucible component at the portion where the raw material comes into contact with the crucible, and the fluorescence characteristics of the obtained phosphor are deteriorated. This is not desirable because it reduces the yield of the product and increases the cost. Further, by sintering, a pulverization step and a classification step for adjusting the required particle size are also required. Therefore, if YAG phosphors or YAG particles can be obtained using only mechanical energy without firing at a high temperature, high-temperature equipment is not required, and highly productive production that does not require a crushing step or a classification step is required. The method can be realized, and the cost of the YAG phosphor or YAG particles can be reduced.

As a method for producing a YAG phosphor including a step using mechanical energy, Patent Document 3 discloses a method in which a raw material powder is treated with a planetary ball mill for 16 to 24 hours to prepare a non-equilibrium powder and calcined at 1100 ° C. Has been done. Further, Non-Patent Document 2, the addition of Al (OH) ₃ as a raw material powder for 6 hours with a planetary ball mill, YAG particles amorphous state (amorphous) (i.e., Y ₃ where the light emitting element is not dissolved Al ₅ O _{12 (} distinguished from YAG phosphor which is Y ₃ Al ₅ O _{12 in} which a luminescent element is dissolved) is prepared and crystallized by firing at about 1200 ° C. These methods require a very long time of mechanical energy input and must be heat treated for crystallization. That is, a method for synthesizing highly crystalline YAG particles or YAG phosphors using only mechanical energy has not yet been achieved.

Japanese Unexamined Patent Publication No. 2010-155891 Japanese Unexamined Patent Publication No. 2008-231218 Japanese Patent No. 2934859

J. Electorochem. soc. vol. 141, No. 5, May1994 Power Technology 129 (2003) 86-91

The present invention is a method for producing an inorganic compound using a metal oxide as a raw material, such as the above-mentioned YAG phosphor, in a shorter time than a production method for mixing and firing by a conventional ball mill method. Another object of the present invention is to provide a method for producing a target inorganic compound without firing at a high temperature.

The present invention that has achieved the above problems
(1) A method for producing an inorganic compound in which a mixture containing a raw material powder containing two or more kinds of metal oxide powders and a flux is treated by a mechanochemical method and the two or more kinds of metal oxide powders are reacted. ..

(2) In the method for producing an inorganic compound according to (1), it is preferable that the treated product is further calcined after being treated by the mechanochemical method.

(3) The method for producing an inorganic compound according to (2) is preferably calcined at 1800 ° C. or lower.

(4) In the method for producing an inorganic compound according to any one of (1) to (3), it is preferable that the inorganic compound obtained by the reaction is a crystalline composite metal oxide.

(5) In the method for producing an inorganic compound according to any one of (1) to (4), the raw material powders are Y ₂ O ₃ powder, Al ₂ O ₃ powder, and Ce, Tb, Eu, Yb, Pr. , Tm and Sm, and preferably contains an oxide powder of at least one dopant selected from the group, and the inorganic compound is a YAG phosphor.

(6) The method for producing an inorganic compound according to any one of (1) to (5) is a step of reacting the two or more kinds of metal oxide powders by a mechanochemical method and a step of removing the flux with an acid. It is preferable to have both.

(7) The method for producing an inorganic compound according to any one of (1) to (6) is at least one in which the flux is selected from the group consisting of metal hydroxides, metal oxides and metal halides. It is preferable to have.

(8) In the method for producing an inorganic compound according to (7), it is preferable that the metal halide is a metal fluoride.

(9) In the method for producing an inorganic compound according to (8), it is preferable that the metal fluoride is at least one selected from the group consisting of BaF ₂ , YF ₃ , AlF ₃ and SrF ₃ .

(10) In the method for producing an inorganic compound according to any one of (7) to (9), the metal hydroxide is Al (OH) ₃ , KOH, Sr (OH) ₂ , NaOH, Ba (OH). It is preferably at least one selected from the group consisting of ₂ , Mg (OH) ₂ and LiOH.

(11) The method for producing an inorganic compound according to any one of (1) to (10) includes a bottomed cylindrical container and a rotor having a tip wing having a curvature smaller than the inner circumference of the container, and the tip thereof. It is preferable that a predetermined clearance is provided between the blade and the inner circumference of the container, and the rotor is rotated to shear the mixture while compressing it with the clearance.

(12) In the method for producing an inorganic compound according to (11), it is preferable that the power of the rotor is 0.1 kW / g or more with respect to the total amount of the raw material powder, and the rotor is rotated for 10 minutes or more. ..

(13) In the method for producing an inorganic compound according to any one of (5) to (12), the amount of the flux added is preferably 4% by mass or more with respect to the raw material powder.

(14) In the method for producing an inorganic compound according to any one of (5) to (13), the proportion of YAG phosphor contained in the product treated by the mechanochemical method is 3% by mass or more of the entire treated product. Is preferable.

According to the present invention, by treating the mixture containing the raw material powder and the flux by the mechanochemical method, the raw material powders can be reacted with each other without firing later, and the raw material powders can be remarkably reacted as compared with the conventional firing method. It can be reacted in a short time.

FIG. 1A is a cross-sectional view perpendicular to the rotation axis of a grinding mill that can be used in the mechanochemical method, and FIG. 1B is a cross-sectional view taken along the line AA'of FIG. 1A. FIG. 2 is a graph showing the excitation and emission spectra of the YAG phosphor. FIG. 3 is a graph showing the relationship between temperature and relative emission intensity. FIG. 4 is a graph showing the XRD analysis results when the treatment conditions of the mechanochemical method were changed (Examples 10 to 12).

The method for producing an inorganic compound of the present invention is characterized in that a mixture containing a raw material powder containing two or more kinds of metal oxide powders and a flux is treated by a mechanochemical method to react the raw material powders with each other. There is. More specifically, the mechanochemical method can be carried out by shearing a mixture containing the raw material powder while compressing it under dry conditions, whereby strain energy is accumulated in the raw material powder and the energy is self-released. , Used as thermal energy, surface modification, crystal structure transition, or solid phase reaction. In the present invention, the raw material powder is mechanochemically treated in the presence of flux, and the generated energy creates a liquid phase on the surface of the raw material to promote the reaction between the raw material powders. Therefore, according to the present invention, the desired inorganic compound can be obtained in a very short time only by mechanochemical treatment without performing high-temperature heat treatment. Further, according to the present invention, a highly crystalline compound can be obtained, and in the present invention using a metal oxide as a raw material, a crystalline composite metal oxide can be obtained. Examples of the crystalline composite metal oxide include Ca ₂ SiO ₄ , Sr ₂ SiO ₄ , Zr ₂ SiO ₄ , SrAl ₂ O ₄ , Ba ₃ MgSi ₂ O ₈ , Li ₄ Ti ₅ O ₁₂ , and Li ₂ Ti ₃ O _7. , LiCoO ₂ , SrTIO ₃ , LaSrMnO ₃ , NaCo ₂ O ₄ , Ca ₃ Co ₄ O ₉ , Bi ₂ Sr ₂ Co ₂ O _y , YAG (YAG phosphor and YAG particles) and the like. However, the material properties can also be improved by calcining the obtained inorganic compound (particularly crystalline composite oxide). For example, when the treated product after treatment by the mechanochemical method (including YAG particles and / or YAG phosphor when the target inorganic compound is, for example, a YAG phosphor) is fired, a single phase is formed at a low temperature. It is obtained, particle growth is promoted, and luminous efficiency is improved.

Examples of the flux include metal hydroxides, metal oxides and metal halides. All of these have actions such as generating a liquid phase between the metal oxide powders of the raw materials to increase the contact area, and by using such a flux, the reaction between the raw material powders by the mechanochemical method can be carried out. It will be possible. Examples of the metal hydroxide include Al (OH) ₃ , KOH, Sr (OH) ₂ , NaOH, Ba (OH) ₂ , Mg (OH) _2, LiOH and the like, and at least one of these is used. be able to. A preferred metal hydroxide is Al (OH) ₃ . Examples of the metal oxide include PbO and B ₂ O ₃ . Further, as the metal halide, metal fluoride and metal chloride are preferable, and examples of this metal include alkali metal, alkaline earth metal, Be, Mg, Y, Al, Pb, Bi and Zn. As the metal halide, metal fluoride is preferable, at least one selected from the group consisting of BaF ₂ , YF ₃ , AlF ₃ and SrF ₃ is more preferable, and BaF ₂ is particularly preferable. The melting point of the flux is, for example, 200 to 1400 ° C., and the volume-based D ₅₀ is, for example, 200 nm to 7 μm (preferably 300 nm to 6 μm, more preferably 400 nm to 5 μm). The amount of flux can be appropriately set in consideration of the type of raw material powder used and the balance with the conditions of mechanochemical treatment, and can be, for example, 4 to 15% by mass with respect to the total amount of raw material powder.

As described above, the mechanochemical method can be carried out more specifically by shearing the mixture containing the raw material powder while compressing it under dry conditions. An example of this method will be described with reference to the drawings. FIG. 1 is a schematic view of a grinding mill capable of applying a compressive force and a shearing force to a mixture of raw material powders, FIG. 1 (a) is a sectional view perpendicular to a rotation axis, and FIG. 1 (b) is a sectional view. It is a cross-sectional view of AA'of FIG. 1 (a). The grinding mill of FIG. 1 includes a bottomed cylindrical container 1 and a rotor 2. The rotor 2 has a tip wing 3 having a curvature smaller than the inner circumference of the bottomed cylindrical container 1, and a clearance 4 is provided between the tip wing 3 and the inner circumference of the bottomed cylindrical container 1. .. Then, by rotating the rotor 2, the mixture 5 of the raw material powder receives the compressive force and the shearing force in the clearance 4.

The conditions for the mechanochemical treatment are appropriately set according to the type and amount of the raw material and the flux, and can be, for example, as follows.

The range of the clearance varies depending on the amount of raw material powder, the difference between the curvature of the tip blade of the rotor and the curvature of the inner circumference of the container, and can be, for example, 20 mm or less. By doing so, a sufficient compressive force and a shearing force can be applied to the mixture of the raw material powders, and the reaction between the raw material powders is promoted. The clearance is preferably 10 mm or less, more preferably 5 mm or less, and particularly preferably 3 mm or less. The lower limit of the clearance is, for example, 100 μm, preferably 1 mm.

The power of rotation of the rotor is, for example, 0.05 kW / g or more with respect to the total mass of the raw material powder. By increasing the rotational power, the solid-phase reaction between the raw material powders is promoted. The rotational power is preferably 0.06 kW / g or more, more preferably 0.08 kW / g or more, and particularly preferably 0.1 kW / g or more. The upper limit of the power of rotation is not particularly limited, but is, for example, 0.5 kW / g. The rotation speed of the rotor varies depending on the size of the device, the shape of the rotor, and the like, but if the rotational power is in the above range, it can be, for example, 1000 to 4000 rpm, preferably 2000 to 3000 rpm.

The rotation time of the rotor can be appropriately set by the rotational power of the rotor, and is, for example, 5 minutes or more (preferably 10 minutes or more). By rotating the rotor for 5 minutes or more, sufficient compressive force and shearing force can be applied to the raw material powder, so that the solid phase reaction of the raw material powder proceeds and the target compound can be obtained. The upper limit of the rotation time of the rotor is not particularly limited, but if it is too long, the crystallinity of the target compound will be lowered and extra energy will be consumed. Therefore, it may be about 10 minutes, or 30 minutes or less. .. However, if the rotational power of the rotor is 0.1 kW / g or more, an inorganic compound having high crystallinity can be obtained without heat treatment even in a very short time of 20 minutes or less.

In the mechanochemical treatment, strain energy is accumulated in the raw material powder by shearing, and the energy is self-released to become thermal energy, so that heat is generated. The mechanochemical treatment may be carried out in a state of heat generation, or may be carried out by cooling by water cooling or the like. In the mechanochemical treatment, the ultimate temperature of the cylindrical container can be set to, for example, about 130 to 500 ° C.

The atmosphere of the mechanochemical treatment is not particularly limited, but may be any of air, an inert gas, and a reducing gas. Of these, a reducing gas is preferable. Examples of the inert gas include nitrogen, helium, argon and the like (particularly nitrogen gas is preferable), and examples of the reducing gas include a mixed gas of the inert gas (particularly nitrogen gas) and 3 to 5% hydrogen gas. Can be mentioned.

The material of the bottomed cylindrical container is not particularly limited, and examples thereof include stainless steel such as SUS304 and carbon steel. Alternatively, a coating may be applied so that impurities are not mixed in the target inorganic compound. The inner diameter of the container is, for example, 50 to 500 mm. Further, the number of tip blades may be 1 or more, preferably 2 or more, and usually 8 or less.

The above-mentioned mechanochemical treatment conditions are not preferable because if the reaction conditions are too weak, the reaction between the raw material powders does not occur, and if the reaction conditions are too strong, the crystals once formed become amorphous. When the conditions of the mechanochemical treatment are inappropriate, the appropriate reaction conditions can be easily set by appropriately changing the conditions according to the reason (unreacted, amorphized, etc.). For example, the optimum conditions in the following cases are as follows.

When the target inorganic compound is a YAG phosphor, the rotational power of the rotor is preferably 0.1 kW / g or more with respect to the total amount of the raw material powder, and the rotor is rotated for 20 minutes or more. By doing so, it is possible to obtain a phosphor having the same characteristics as the phosphor obtained by the conventional firing method (particularly, the internal quantum yield when excited with light having a wavelength of 450 to 460 nm). When producing YAG, it is preferable to use Al (OH) ₃ as the flux, or BaF ₂ , YF ₃ , AlF ₃ or SrF ₃ , and Al (OH) ₃ or BaF ₂ is preferable. The amount of Al (OH) ₃ is preferably 4 to 15% by mass (more preferably 10 to 15% by mass) with respect to the total amount of the raw material powder, and the volume-based D ₅₀ is preferably 400 to 800 nm. When Al (OH) ₃ is used, the ultimate temperature of the cylindrical container after the mechanochemical treatment is preferably 300 to 450 ° C. (more preferably 340 to 440 ° C.). The amount of BaF ₂ , YF ₃ , AlF ₃ or SrF ₃ is preferably 4 to 12% by mass, more preferably 4 to 10% by mass (particularly 5 to 8% by mass) with respect to the total amount of the raw material powder. .. The volume-based D ₅₀ of BaF ₂ , YF ₃ , AlF ₃ or SrF ₃ is, for example, 4 to 10 μm, preferably 5 to 9 μm, and more preferably 6 to 8 μm. When BaF ₂ , YF ₃ , AlF ₃ or SrF ₃ is used, the ultimate temperature of the cylindrical container after the mechanochemical treatment is preferably 100 to 300 ° C. (more preferably 140 to 270 ° C.). The temperature reached by the cylindrical container after the mechanochemical treatment can change depending on the power of the mechanochemical treatment, the amount of raw material powder or flux, the temperature, the humidity, and the like. By adopting the above conditions, the proportion of the YAG phosphor contained in the product treated by the mechanochemical method can be 3% by mass or more of the entire treated product (after treatment with the acid described later). The proportion of the YAG phosphor is preferably 15% by mass or more, more preferably 30% by mass or more. The upper limit is not particularly limited, and is preferably 100% by mass, but may be about 40% by mass or less.

In the present invention, it is preferable to have both a step of reacting the metal oxide powder by a mechanochemical treatment and a step of removing the flux with an acid. In the present invention, as will be described later, the inorganic compound synthesized by the mechanochemical method may be further calcined, but when not calcined, the flux is subjected to the acid after reacting the metal oxide powder particularly by the mechanochemical treatment. It is preferable to remove. As the acid, an inorganic acid such as hydrochloric acid or sulfuric acid can be used. The treatment with acid may be, for example, 1 to 3 hours, and after the acid treatment, it is washed with pure water and then at about 100 to 400 ° C. (preferably 200 to 300 ° C.) for 1 hour or more (preferably 2 hours or more, It is more preferable to heat it for 3 hours or more, more preferably 4 hours or more, usually 10 hours or less) to sufficiently remove the water.

Further, the inorganic compound synthesized by the mechanochemical method, particularly YAG (that is, YAG phosphor and / or YAG particles) is calcined, and more specifically, the processed product treated by the mechanochemical method is calcined to improve the characteristics. You can also do it. Since the inorganic compound such as the YAG phosphor obtained by mechanochemical is made into composite particles, the bonding between the particles is strong and the solid phase reaction is promoted. It has already been described that the flux is removed by an acid after the metal oxide powder is reacted by the mechanochemical treatment. However, if the flux is not removed before firing and the flux is present, the flux is hardened. It is more preferable because the phase-liquid phase reaction is promoted.

When the inorganic compound to be fired is YAG, the ratio of the YAG phosphor and / or the YAG particles to the entire processed product after being treated by the mechanochemical method is preferably 3% by mass or more, more preferably. It is preferably 30% by mass or more, and the upper limit is not particularly limited and is preferably 100% by mass, but usually it is often 80% by mass, and may be about 60% by mass. The firing temperature is preferably 1000 ° C. to 1800 ° C., more preferably 1200 ° C. to 1700 ° C., and even more preferably 1500 ° C. to 1600 ° C. The firing time is preferably 1 hour to 6 hours, more preferably 3 hours. The atmosphere of firing is not particularly limited, and may be any of air, an inert gas, and a reducing gas, but an inert gas or a reducing gas is preferable. Examples of the inert gas include nitrogen, helium, argon and the like (particularly nitrogen gas is preferable), and examples of the reducing gas include a mixed gas of the inert gas (particularly nitrogen gas) and 3 to 5% hydrogen gas. Can be mentioned. The pressure at the time of firing is preferably atmospheric pressure.

It is preferable to remove the flux of the obtained phosphor with an acid. As the acid, an inorganic acid such as hydrochloric acid or sulfuric acid can be used. The treatment with acid may be, for example, 1 to 3 hours, and after the acid treatment, it is washed with pure water and then at about 100 to 400 ° C. (preferably 200 to 300 ° C.) for 1 hour or more (preferably 2 hours or more, It is more preferable to heat it for 3 hours or more, more preferably 4 hours or more, usually 10 hours or less) to sufficiently remove the water.

The metal oxide powder used as the raw material powder may be appropriately adjusted according to the target inorganic compound. The target inorganic compound and its raw material (the left side of ":" is the target inorganic compound and the right side is the metal oxide as the raw material) are as follows, for example.
Ca ₂ SiO ₄ : CaCO ₃ , SiO ₂
Sr ₂ SiO ₄ : SrCO ₃ , SiO ₂
SrAl ₂ O ₄ : SrCO ₃ , Al ₂ O ₃
Ba ₃ MgSi ₂ O ₈ : BaCO ₃ , MgO, SiO ₂
Li ₄ Ti ₅ O ₁₂ : Li ₂ O, Li ₂ CO ₃ , TiO ₂
Li ₂ Ti ₃ O ₇ : Li ₂ O, Li ₂ CO ₃ , TiO ₂
LiCoO ₂ : Li ₂ O, Li ₂ CO ₃ , Co ₂ O ₃
SrTiO ₃ : SrCO ₃ , TiO ₂
LaSrMnO ₃ : La ₂ O ₃ , SrCO ₃ , MnO ₂
NaCo ₂ O ₄ : Na ₂ O, Co ₂ O ₃
Ca ₃ Co ₄ O ₉ : CaCO ₃ , Co ₂ O ₃
Bi ₂ Sr ₂ Co ₂ O _y : BiO ₂ , SrCO ₃ , Co ₂ O ₃
Zr ₂ SiO ₄ : ZrO, SiO ₂
YAG phosphor: an oxide of at least one dopant selected from the group consisting of Y ₂ O ₃ , Al ₂ O ₃ , Ce, Tb, Eu, Yb, Pr, Tm and Sm (Note that Y source and Al source). may be used YAlO ₃ with _{Y 2 O 3, Al 2 O} 3 as may be used YAlO ₃ instead of _{Y 2 O 3, Al 2 O} 3)
In particular, in the case of a YAG phosphor, the volume-based D ₅₀ of the raw material powder is, for example, 300 to 600 nm.

The YAG phosphor obtained by the production method of the present invention is a YAG phosphor containing a YAG crystal as a mother crystal and containing at least one dopant selected from the group consisting of Ce, Tb, Eu, Yb, Pr, Tm and Sm. Is. This YAG phosphor can be represented by the composition formula Y _3-x M _x Al ₅ O ₁₂ . In the composition formula, M is the above-mentioned dopant element, is a component that replaces Y and becomes a light emitting center, and is also called an activator. The dopant is preferably at least one selected from the group consisting of Ce, Tb and Yb, and Ce is particularly preferable. The x is a value satisfying 0 <x ≦ 1. The volume-based D ₅₀ of the YAG phosphor is, for example, 600 nm to 20 μm.

The value of x is preferably 0.003 to 0.2. If the value of x is less than 0.003, fluorescence with sufficient emission intensity cannot be obtained. On the other hand, when the value of x exceeds 0.2, energy is transferred between activators and concentration quenching occurs. Concentration quenching means that energy transfer between adjacent molecules occurs and the original energy is not sufficiently radiated to the outside as fluorescence (non-fluorescence transition), so that the fluorescence intensity increases as the concentration of the activator increases. It is a phenomenon that does not occur. The value of x is preferably 0.01 to 0.2. By setting x to 0.01 or more, a phosphor having an emission intensity suitable for use in a light emitting device is obtained.

Since the raw material powder of the YAG phosphor obtained by the production method of the present invention is processed by the mechanochemical method, the fluorescence is equal to or higher than that of the YAG phosphor obtained by the conventional firing method in a very short time. A YAG phosphor having characteristics can be obtained. Specifically, the internal quantum yield (25 ° C.) when excited with light having a wavelength of 450 to 460 nm can be 40% or more, preferably 50% or more, and more preferably 60% or more. The internal quantum yield of 60% or more is almost the same as that of the phosphor obtained by the conventional firing method.

The YAG phosphor of the present invention is preferably a polycrystalline material, and the half width of the diffraction peak of the (400) plane in the XRD analysis is preferably 0.1 to 0.8 °. The diffraction peak of the (400) plane is the YAG phase, and the fact that the half width of the diffraction peak of the YAG phase is within the above range means that the crystallinity of the phosphor is high. The half width is preferably 0.7 ° or less, more preferably 0.4 ° or less.

Further, the YAG phosphor produced according to the present invention may contain a YAP (YAlO ₃ ) phase in addition to the YAG phase. The plane index of the YAlO _three- phase is (121), and a diffraction peak appears near 34 °. In the YAG phosphor obtained by the present invention, the ratio of the diffraction peak intensity of the (400) plane to the sum of the diffraction peak intensities of the (121) plane and the diffraction peak intensity of the (400) plane is, for example, 20% or more, which is preferable. Is 30% or more, more preferably 40% or more. The upper limit of the ratio of the diffraction peak intensities is most preferably 100%, and may be about 80% or less. Further, when a YAG phosphor is obtained according to the present invention, YAG particles (Y ₃ Al ₅ O ₁₂ in which a luminescent element is not dissolved in solid solution) can also be produced.

Further, the external quantum efficiency at 25 ° C. when excited by light having a wavelength of 450 to 460 nm is preferably 20% or more, more preferably 30% or more, still more preferably 40% or more. The upper limit of the external quantum efficiency is not particularly limited, but is usually about 60%. Further, the absorptance of wavelengths of 450 to 460 nm is preferably 45% or more, more preferably 50% or more. The upper limit of the absorption rate is not particularly limited, but is, for example, about 75%.

The YAG phosphor of the present invention has, for example, an emission intensity at 150 ° C. (hereinafter, "temperature quenching characteristic at 150 ° C.") with respect to an emission intensity at 25 ° C. when excited by light having a wavelength of 450 to 460 nm. It is ~ 95%, preferably 80% or more, and more preferably 90% or more. Further, the emission intensity at 200 ° C. (hereinafter, “temperature quenching characteristic at 200 ° C.”) with respect to the emission intensity at 25 ° C. when excited by light having a wavelength of 450 to 460 nm is, for example, 65 to 90%. It is preferably 70% or more, more preferably 80% or more (particularly 85% or more).

The YAG phosphor of the present invention is efficiently excited in the visible light region from near ultraviolet light and emits yellow light. The wavelength of the excitation light is preferably 265 to 470 nm, more preferably 365 to 470 nm, and even more preferably 450 to 460 nm. When the YAG phosphor of the present invention is excited with light having a wavelength of 450 to 460 nm, the peak of the emission wavelength is, for example, 540 to 600 nm. It has also been confirmed that it emits yellow light when excited by vacuum ultraviolet rays of 100 to 190 nm, ultraviolet rays of 190 to 380 nm, electron beams, and the like. A light emitting device including a light emitting element such as an LED or LD made of a nitride semiconductor that emits ultraviolet to blue (particularly blue) light and the YAG phosphor of the present invention, wherein the light of the light emitting element is used as excitation light. The light emitting device that emits yellow light from the YAG phosphor of the present invention can be a high output (for example, 5 W or more) light emitting device because the temperature extinguishing characteristics of the YAG phosphor of the present invention are good. Such a light emitting device is also the present invention. include. Examples of such a light emitting device include a vacuum fluorescent display (VFD), a field emission display (FED), a plasma display panel (PDP), a cathode ray tube (CRT), and the like.

The present application claims the priority benefit under Japanese Patent Application No. 2015-133594 filed on July 2, 2015 and Japanese Patent Application No. 2015-190173 filed on September 28, 2015. To do. The entire contents of the specification of Japanese Patent Application No. 2015-133594 filed on July 2, 2015 and Japanese Patent Application No. 2015-190173 filed on September 28, 2015 are referred to in this application. Will be used for.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited by the following examples, and it is of course possible to carry out the invention with appropriate modifications within the range that can be adapted to the above-mentioned purpose, and all of them are technical of the present invention. Included in the range.

Example 1
As raw materials for YAG phosphors, Y ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.6 μm), Al ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.4 μm), CeO Weigh a total of 30 g of powder of ₂ (manufactured by high-purity chemistry, volume-based D ₅₀ : 0.3 μm) with a chemical quantitative ratio such that the composition of the phosphor to be produced is Y _2.97 Ce _0.03 Al ₅ O ₁₂ . Al (OH) ₃ was added in an amount of 12.5 wt% (D ₅₀ : 0.75 μm based on the volume of Heidilite H43M manufactured by Showa Denko) and charged into the grinding mill shown in FIG. The bottomed cylindrical container 1 is made of SUS304 and has an inner diameter of 80 mm, and the clearance 4 between the inner circumference of the container 1 and the tip blade of the rotor 2 is 1 mm. Such a grinding mill was rotated at a rotation speed of 3000 rpm and a required power of 3 kW for 30 minutes to perform mechanochemical treatment. The temperature of the grinding mill at that time was 350 ° C.

In order to remove impurities and the like of the obtained fluorescent substance, the mixture was stirred in dilute hydrochloric acid for 2 hours, washed with pure water, and then heated to 170 ° C. to sufficiently remove water to obtain a fluorescent substance powder.

The crystal structure of the obtained fluorescent powder was analyzed using an XRD apparatus manufactured by Rigaku. The measurement was carried out with CuKα rays, and λ = 1.5418 nm and θ = 10 to 70 °. As a result, the obtained crystal of the phosphor powder is a composite particle of polycrystalline YAG and YAP (YAlO ₃ ), and is (400) with respect to the total of the diffraction peak intensity of the (400) plane and the diffraction peak intensity of the (121) plane. ) The ratio of the diffraction peak intensities of the plane was 30.6%. As a result of Rietveld analysis, the YAG phase was 3.6 wt%. The half width of the (400) plane was 0.668 °.

Furthermore, the emission characteristics of the obtained phosphor powder were measured using an F-7000 type spectrofluorometer manufactured by Hitachi High-Tech, under the conditions of excitation side slit: 2.5 nm, fluorescence side slit: 2.5 nm, and photomal voltage 350 V. It was measured. As a result, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 550 nm was confirmed. Then, the quantum yield measurement and the temperature quenching measurement were performed using an absolute quantum yield measuring device (Quantaurus-QY C11347-01) manufactured by Hamamatsu Photonics. As a result, the internal quantum yield at 25 ° C. was 27.3% when the wavelength of the excitation light was 450 nm, and the emission intensity at 150 ° C. was 86% with respect to the emission intensity at 25 ° C.

Example 2
A fluorescent powder was obtained in the same manner as in Example 1 except that the ultimate temperature of the grinding mill was 438 ° C.

As a result of measuring the crystal structure of the obtained phosphor powder in the same manner as in Example 1, the crystal of the obtained phosphor powder is a composite particle of polycrystalline YAG and YAP, and the diffraction peak intensity of the (400) plane. The ratio of the diffraction peak intensity of the (400) plane to the total diffraction peak intensity of the (121) plane was 48.9%. As a result of Rietveld analysis, the YAG phase was 15.5 wt%. The half width of the (400) plane was 0.158 °.

Further, as a result of measuring the emission characteristics of the obtained phosphor powder in the same manner as in Example 1, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 550 nm was confirmed. The internal quantum yield at 25 ° C. was 13.2% when the wavelength of the excitation light was 450 nm, and the emission intensity at 150 ° C. was 83% with respect to the emission intensity at 25 ° C.

Example 3
As raw materials for YAG phosphors, Y ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.6 μm), Al ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.4 μm), CeO Weigh a total of 30 g of ₂ (high-purity chemical product, volume-based D ₅₀ : 0.3 μm) powder with a chemical quantitative ratio such that the composition of the phosphor to be produced is Y _2.97 Ce _0.03 Al ₅ O ₁₂ . 6 wt% of BaF ₂ (volume standard D ₅₀ : 6 μm) was added and charged into the grinding mill shown in FIG. The inside of the chamber container of the grinding mill was water-cooled at 1 L / min. The bottomed cylindrical container 1 is made of SUS304 and has an inner diameter of 80 mm, and the clearance 4 between the inner circumference of the container 1 and the tip blade of the rotor 2 is 1 mm. Such a grinding mill was rotated at a rotation speed of 3000 rpm and a required power of 3 kW for 10 minutes to perform mechanochemical treatment. The temperature of the grinding mill at that time was 114 ° C.

In order to remove impurities and the like of the obtained fluorescent substance, the mixture was stirred in dilute hydrochloric acid for 2 hours, washed with pure water, and then heated to 170 ° C. to sufficiently remove water to obtain a fluorescent substance powder.

As a result of measuring the crystal structure of the obtained phosphor powder in the same manner as in Example 1, the crystal of the obtained phosphor powder is a composite particle of polycrystalline YAG and YAP, and the diffraction peak intensity of the (400) plane. The ratio of the diffraction peak intensity of the (400) plane to the total diffraction peak intensity of the (121) plane was 70.7%. As a result of Rietveld analysis, the YAG phase was 31.5 wt%. The full width at half maximum of the (400) plane was 0.224 °.

Further, as a result of measuring the emission characteristics of the obtained phosphor powder in the same manner as in Example 1, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed. Further, when the wavelength of the excitation light was 450 nm, the internal quantum yield at 25 ° C. was 32.5%, and the emission intensity at 150 ° C. was 85% with respect to the emission intensity at 25 ° C.

Example 4
A fluorescent powder was obtained in the same manner as in Example 3 except that the grinding mill was not water-cooled. The temperature of the grinding mill at that time was 210 ° C.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystal of the phosphor powder is a composite particle of polycrystalline YAG and YAP, and the diffraction peak intensity of the (400) plane is relative to the sum of the diffraction peak intensity of the (400) plane and the diffraction peak intensity of the (121) plane. The ratio was 25.9%. The full width at half maximum of the (400) plane was 0.326 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 51.8%, and the emission intensity at 150 ° C. was It was 84%.

Example 5
A fluorescent powder was obtained in the same manner as in Example 4 except that the treatment time was 15 minutes. The temperature of the grinding mill at that time was 217 ° C.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystal of the phosphor powder is a composite particle of polycrystalline YAG and YAP, and the diffraction peak intensity of the (400) plane is relative to the sum of the diffraction peak intensity of the (400) plane and the diffraction peak intensity of the (121) plane. The ratio was 28.9%. The half width of the (400) plane was 0.639 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 55.2%, and the emission intensity at 150 ° C. was It was 90%.

Example 6
A fluorescent powder was obtained in the same manner as in Example 4 except that the treatment time was 20 minutes. The temperature of the grinding mill at that time was 210 ° C.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystal of the phosphor powder is a composite particle of polycrystalline YAG and YAP, and the diffraction peak intensity of the (400) plane is relative to the sum of the diffraction peak intensity of the (400) plane and the diffraction peak intensity of the (121) plane. The ratio was 32.3%. The full width at half maximum of the (400) plane was 0.386 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 60.8%, and the emission intensity at 150 ° C. was It was 88%.

Example 7
A fluorescent powder was obtained in the same manner as in Example 4 except that the treatment time was 10 minutes. The temperature of the grinding mill at that time was 255 ° C.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystal of the phosphor powder is a composite particle of polycrystalline YAG and YAP, and the diffraction peak intensity of the (400) plane is relative to the sum of the diffraction peak intensity of the (400) plane and the diffraction peak intensity of the (121) plane. The ratio was 62.6%. The half width of the (400) plane was 0.333 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 56.5%, and the emission intensity at 150 ° C. was It was 88%.

Example 8
A fluorescent powder was obtained in the same manner as in Example 4 except that the treatment time was 15 minutes. The temperature of the grinding mill at that time was 270 ° C.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystal of the phosphor powder is a composite particle of polycrystalline YAG and YAP, and the diffraction peak intensity of the (400) plane is relative to the sum of the diffraction peak intensity of the (400) plane and the diffraction peak intensity of the (121) plane. The ratio was 64.2%. The full width at half maximum of the (400) plane was 0.299 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 54.9%, and the emission intensity at 150 ° C. was It was 89%.

Example 9
A fluorescent powder was obtained in the same manner as in Example 4 except that the treatment time was 20 minutes. The temperature of the grinding mill at that time was 270 ° C.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystal of the phosphor powder is a composite particle of polycrystalline YAG and YAP, and the diffraction peak intensity of the (400) plane is relative to the sum of the diffraction peak intensity of the (400) plane and the diffraction peak intensity of the (121) plane. The ratio was 59.9%. The full width at half maximum of the (400) plane was 0.395 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 54.5%, and the emission intensity at 150 ° C. was It was 90%.

Example 10
A fluorescent powder was obtained in the same manner as in Example 4 except that the treatment time was 10 minutes and the amount of BaF ₂ added was 10 wt%. The temperature of the grinding mill at that time was 140 ° C.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystal of the phosphor powder is a composite particle of polycrystalline YAG and YAP, and the diffraction peak intensity of the (400) plane is relative to the sum of the diffraction peak intensity of the (400) plane and the diffraction peak intensity of the (121) plane. The ratio was 77.2%. The half width of the (400) plane was 0.232 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 33.3%, and the emission intensity at 150 ° C. was It was 84%.

Example 11
A fluorescent powder was obtained in the same manner as in Example 10 except that the treatment time was set to 20 minutes.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystal of the phosphor powder is a composite particle of polycrystalline YAG and YAP, and the diffraction peak intensity of the (400) plane is relative to the sum of the diffraction peak intensity of the (400) plane and the diffraction peak intensity of the (121) plane. The ratio was 73.5%. The full width at half maximum of the (400) plane was 0.251 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 30.7%, and the emission intensity at 150 ° C. was It was 86%.

Example 12
A fluorescent powder was obtained in the same manner as in Example 10 except that the treatment time was set to 30 minutes.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystal of the phosphor powder is a composite particle of polycrystalline YAG and YAP, and the diffraction peak intensity of the (400) plane is relative to the sum of the diffraction peak intensity of the (400) plane and the diffraction peak intensity of the (121) plane. The ratio was 73.3%. The full width at half maximum of the (400) plane was 0.284 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 23.5%, and the emission intensity at 150 ° C. was It was 87%.

Example 13
As raw materials for YAG phosphors, Y ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.6 μm), Al ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.4 μm), CeO Weigh a total of 30 g of ₂ (high-purity chemical product, volume-based D ₅₀ : 0.3 μm) powder with a chemical quantitative ratio such that the composition of the phosphor to be produced is Y _2.97 Ce _0.03 Al ₅ O ₁₂ . AlF ₃ (volume standard D ₅₀ : 7 μm) was added in an amount of 6 wt% and charged into the grinding mill shown in FIG. The inside of the chamber container of the grinding mill was water-cooled at 1 L / min. The bottomed cylindrical container 1 is made of SUS304 and has an inner diameter of 80 mm, and the clearance 4 between the inner circumference of the container 1 and the tip blade of the rotor 2 is 1 mm. Such a grinding mill was rotated at a rotation speed of 3000 rpm and a required power of 2.5 kW for 10 minutes to perform mechanochemical treatment. The temperature of the grinding mill at that time was 74 ° C.

In order to remove impurities and the like of the obtained fluorescent substance, the mixture was stirred in dilute hydrochloric acid for 2 hours, washed with pure water, and then heated to 170 ° C. to sufficiently remove water to obtain a fluorescent substance powder.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystals of the fluorescent substance powder were composite particles of polycrystalline YAG, Y ₂ O ₃ , and Al ₂ O ₃ , and the YAP phase could not be confirmed. The full width at half maximum of the (400) plane was 0.355 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 30.5%, and the emission intensity at 150 ° C. was It was 84%.

Example 14
A phosphor powder was obtained in the same manner as in Example 13 except that 10 wt% of AlF ₃ was added. The temperature of the grinding mill at that time was 110 ° C.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystals of the fluorescent substance powder were composite particles of polycrystalline YAG, Y ₂ O ₃ , and Al ₂ O ₃ , and the YAP phase could not be confirmed. The half width of the (400) plane was 0.492 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 45.3%, and the emission intensity at 150 ° C. was It was 86%.

Example 15
A fluorescent powder was obtained in the same manner as in Example 14 except that the treatment time was 15 minutes. The temperature of the grinding mill at that time was 99.5 ° C.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystals of the fluorescent substance powder were composite particles of polycrystalline YAG, Y ₂ O ₃ , and Al ₂ O ₃ , and the YAP phase could not be confirmed. The half width of the (400) plane was 0.335 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 46.7%, and the emission intensity at 150 ° C. was It was 87%.

Example 16
As raw materials for YAG phosphors, Y ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.6 μm), Al ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.4 μm), CeO Weigh a total of 30 g of ₂ (high-purity chemical, volume-based D ₅₀ : 0.3 μm) powders at a chemical quantitative ratio such that the composition of the phosphor to be produced is Y _2.97 Ce _0.03 Al ₅ O ₁₂ . 6 wt% of YF ₃ (volume standard D ₅₀ : 6 μm) was added and charged into the grinding mill shown in FIG. The inside of the chamber container of the grinding mill was water-cooled at 1 L / min. The bottomed cylindrical container 1 is made of SUS304 and has an inner diameter of 80 mm, and the clearance 4 between the inner circumference of the container 1 and the tip blade of the rotor 2 is 1 mm. Such a grinding mill was rotated at a rotation speed of 3000 rpm and a required power of 3 kW for 10 minutes to perform mechanochemical treatment. The temperature of the grinding mill at that time was 140 ° C.

In order to remove impurities and the like of the obtained fluorescent substance, the mixture was stirred in dilute hydrochloric acid for 2 hours, washed with pure water, and then heated to 170 ° C. to sufficiently remove water to obtain a fluorescent substance powder.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystals of the fluorescent substance powder were composite particles of polycrystalline YAG, Y ₂ O ₃ , and Al ₂ O ₃ , and the YAP phase could not be confirmed. The full width at half maximum of the (400) plane was 0.296 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 11.5%, and the emission intensity at 150 ° C. was It was 73%.

Example 17
A fluorescent powder was obtained in the same manner as in Example 16 except that the treatment time was 15 minutes. The temperature of the grinding mill at that time was 137 ° C.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystals of the fluorescent substance powder were composite particles of polycrystalline YAG, Y ₂ O ₃ , and Al ₂ O ₃ , and the YAP phase could not be confirmed. The half width of the (400) plane was 0.341 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 41.2%, and the emission intensity at 150 ° C. was It was 86%.

Example 18
A fluorescent powder was obtained in the same manner as in Example 16 except that the amount of YF ₃ added was 10 wt%. The temperature of the grinding mill at that time was 118 ° C.

The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, the crystals of the fluorescent substance powder were composite particles of polycrystalline YAG, Y ₂ O ₃ , and Al ₂ O ₃ , and the YAP phase could not be confirmed. The half width of the (400) plane was 0.350 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 57.8%, and the emission intensity at 150 ° C. was It was 88%.

Example 19
A fluorescent powder was obtained in the same manner as in Example 18 except that the treatment time was 15 minutes. The temperature of the grinding mill at that time was 87 ° C.

The crystal structure and luminescence characteristics of the obtained phosphor powder were measured by the same method as in Example 1. As a result, the crystals of the fluorescent substance powder were composite particles of polycrystalline YAG, Y ₂ O ₃ , and Al ₂ O ₃ , and the YAP phase could not be confirmed. The half width of the (400) plane was 0.313 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 57.3%, and the emission intensity at 150 ° C. was It was 89%.

Comparative Example 1
The mechanochemical treatment was carried out in the same manner as in Example 10 except that the treatment time was set to 30 minutes and no flux was added.

The crystal structure of the obtained powder was measured in the same manner as in Example 1. As a result, the formation of the YAG / YAP phase was not confirmed, and the diffraction patterns of the raw materials Y ₂ O ₃ , Al ₂ O ₃ , and Ce O ₂ were confirmed.

The test conditions and results of Examples 1 to 19 and Comparative Example 1 are shown in Tables 1 and 2. Table 2 also shows the temperature quenching characteristics at 200 ° C., the external quantum yield when excited by light having a wavelength of 450 to 460 nm, and the absorption rate of light having a wavelength of 450 to 460 nm.

From Tables 1 and 2, it can be seen that in Examples 1 to 19 in which the mechanochemical treatment was performed using a grinding mill, the YAG phosphor was produced in a short treatment time of 10 to 30 minutes. In addition, YAG particles were also confirmed by EDX analysis of the cross-sectional SEM image, and it can be confirmed from the XRD results that the obtained YAG phosphors and YAG particles are not amorphous (amorphous) and have high crystallinity. .. In particular, in Examples 4 to 9, 18 and 19, YAG phosphors having an internal quantum yield of more than 50% were obtained. The temperature of the grinding mill is extremely low, about 300 ° C or less, and does not require a special heat-resistant material.

FIG. 2 is a graph showing the excitation spectra and emission spectra of Examples 6, 15 and 18. All of them have an excitation spectrum of about 365 to 500 nm, and yellow emission having a peak of an emission spectrum near 540 nm has been confirmed.

FIG. 3 is a graph obtained by measuring and plotting the light emission intensity when the temperature is changed to 200 ° C. (the light emission intensity at 25 ° C. in each example is 100) in Examples 5 to 9. .. It can be seen that all the examples show good temperature quenching characteristics of 80% or more at 200 ° C.

FIG. 4 is a graph showing the XRD analysis results of Examples 10 to 12, and there is a tendency that the crystallinity tends to be relatively high when fluoride is added and the treatment time is short.

Example 20
As raw materials for YAG phosphors, Y ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.6 μm), Al ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.4 μm), CeO Weigh a total of 30 g of ₂ (high-purity chemical, volume-based D ₅₀ : 0.3 μm) powders at a chemical quantitative ratio such that the composition of the phosphor to be produced is Y _2.97 Ce _0.03 Al ₅ O ₁₂ . 6 wt% of BaF ₂ (volume-based D ₅₀ : 6 μm) was added and charged into the grinding mill shown in FIG. The inside of the chamber container of the grinding mill was water-cooled at 1 L / min. The bottomed cylindrical container 1 is made of SUS304 and has an inner diameter of 80 mm, and the clearance 4 between the inner circumference of the container 1 and the tip blade of the rotor 2 is 1 mm. Such a grinding mill was rotated at a rotation speed of 3000 rpm and a required power of 3 kW for 20 minutes to perform mechanochemical treatment. The temperature of the grinding mill at that time was 210 ° C.

5 g of the obtained processed product was put into an alumina crucible and fired in a graphite furnace at 1200 ° C. for 3 hours. The firing atmosphere was a nitrogen gas atmosphere. In order to remove impurities and the like of the obtained fluorescent substance, the mixture was stirred in dilute hydrochloric acid for 2 hours, washed with pure water, and then heated to 170 ° C. to sufficiently remove water to obtain a fluorescent substance powder. The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, it was confirmed that a YAG single phase was obtained. The half width of the (400) plane was 0.235 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 70.9%, and the emission intensity at 150 ° C. was It was 90%.

Example 21
A YAG phosphor was obtained in the same manner as in Example 20 except that the firing temperature was set to 1500 ° C. The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, it was confirmed that a YAG single phase was obtained. The full width at half maximum of the (400) plane was 0.157 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 80.9%, and the emission intensity at 150 ° C. was It was 95%.

Example 22
As raw materials for YAG phosphors, Y ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.6 μm), Al ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.4 μm), CeO Weigh a total of 30 g of ₂ (high-purity chemical product, volume-based D ₅₀ : 0.3 μm) powder with a chemical quantitative ratio such that the composition of the phosphor to be produced is Y _2.97 Ce _0.03 Al ₅ O ₁₂ . AlF ₃ (volume standard D ₅₀ : 7 μm) was added in an amount of 10 wt% and charged into the grinding mill shown in FIG. The inside of the chamber container of the grinding mill was water-cooled at 1 L / min. The bottomed cylindrical container 1 is made of SUS304 and has an inner diameter of 80 mm, and the clearance 4 between the inner circumference of the container 1 and the tip blade of the rotor 2 is 1 mm. Such a grinding mill was rotated at a rotation speed of 3000 rpm and a required power of 2.5 kW for 15 minutes to perform mechanochemical treatment. The temperature of the grinding mill at that time was 99.5 ° C.
5 g of the obtained processed product was put into an alumina crucible and fired in a graphite furnace at 1200 ° C. for 3 hours. The firing atmosphere was a nitrogen gas atmosphere. In order to remove impurities and the like of the obtained fluorescent substance, the mixture was stirred in dilute hydrochloric acid for 2 hours, washed with pure water, and then heated to 170 ° C. to sufficiently remove water to obtain a fluorescent substance powder. The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, it was confirmed that a YAG single phase was obtained. The full width at half maximum of the (400) plane was 0.236 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 60.5%, and the emission intensity at 150 ° C. was It was 90%.

Example 23
A fluorescent powder was obtained in the same manner as in Example 22 except that the firing temperature was set to 1500 ° C. The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, it was confirmed that a YAG single phase was obtained. The half width of the (400) plane was 0.156 °, and yellow emission with an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, and the internal quantum at 25 ° C. The yield was 70.2%, and the emission intensity at 150 ° C. was 94%.

Example 24
As raw materials for YAG phosphors, Y ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.6 μm), Al ₂ O ₃ (manufactured by high-purity chemicals, volume-based D ₅₀ : 0.4 μm), CeO Weigh a total of 30 g of ₂ (high-purity chemical, volume-based D ₅₀ : 0.3 μm) powders at a chemical quantitative ratio such that the composition of the phosphor to be produced is Y _2.97 Ce _0.03 Al ₅ O ₁₂ . 10 wt% of YF ₃ (volume standard D ₅₀ : 6 μm) was added and charged into the grinding mill shown in FIG. The inside of the chamber container of the grinding mill was water-cooled at 1 L / min. The bottomed cylindrical container 1 is made of SUS304 and has an inner diameter of 80 mm, and the clearance 4 between the inner circumference of the container 1 and the tip blade of the rotor 2 is 1 mm. Such a grinding mill was rotated at a rotation speed of 3000 rpm and a required power of 3 kW for 10 minutes to perform mechanochemical treatment. The temperature of the grinding mill at that time was 118 ° C.

5 g of the obtained processed product was put into an alumina crucible and fired in a graphite furnace at 1200 ° C. for 3 hours. The firing atmosphere was a nitrogen gas atmosphere. In order to remove impurities and the like of the obtained fluorescent substance, the mixture was stirred in dilute hydrochloric acid for 2 hours, washed with pure water, and then heated to 170 ° C. to sufficiently remove water to obtain a fluorescent substance powder. As a result, it was confirmed that a YAG single phase was obtained. The half width of the (400) plane was 0.234 °. Further, yellow emission having an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, the internal quantum yield at 25 ° C. was 65.2%, and the emission intensity at 150 ° C. was It was 89%.

Example 25
A fluorescent powder was obtained in the same manner as in Example 24 except that the firing temperature was set to 1500 ° C. The crystal structure and luminescence characteristics of the obtained fluorescent powder were measured by the same method as in Example 1. As a result, it was confirmed that a YAG single phase was obtained. The half width of the (400) plane was 0.154 °, and yellow emission with an excitation spectrum up to about 365 to 500 nm and a peak emission spectrum near 540 nm was confirmed, and the internal quantum at 25 ° C. The yield was 72.2%, and the emission intensity at 150 ° C. was 95%.

Compared with the conventional method by firing, the method for producing an inorganic compound of the present invention does not require high-temperature equipment, and does not require a pulverization step or classification after sintering. Furthermore, since it can be synthesized in a very short time, the productivity is high. Further, the YAG phosphor produced in the present invention is suitably used for a light emitting device such as a vacuum fluorescent display (VFD), a field emission display (FED), a plasma display panel (PDP), and a cathode ray tube (CRT). YAG particles are also used as optical materials and heat-resistant materials, and are industrially useful.

1 Bottomed cylindrical container, 2 rotor, 3 tip wing, 4 clearance, 5 mixture of raw material powder

Claims (9)

A method for producing an inorganic compound in which a mixture containing a raw material powder containing two or more kinds of metal oxide powders and a flux is treated by a mechanochemical method and the two or more kinds of metal oxide powders are reacted .
The flux is at least one selected from YF ₃ and AlF ₃ .
With a bottomed cylindrical container,
With a rotor with a tip wing with a curvature smaller than the inner circumference of this container,
A predetermined clearance is provided between the tip wing and the inner circumference of the container.
A method for producing an inorganic compound, in which the rotor is rotated for 5 minutes or more and 30 minutes or less to shear the mixture while compressing it with the clearance . The method for producing an inorganic compound according to claim 1, wherein the treated product is further calcined after being treated by the mechanochemical method. The method for producing an inorganic compound according to claim 2, which is fired at 1800 ° C. or lower. The method for producing an inorganic compound according to any one of claims 1 to 3, wherein the inorganic compound obtained by the reaction is a crystalline composite metal oxide. The raw material powder contains a Y ₂ O ₃ powder, an Al ₂ O ₃ powder, and an oxide powder of at least one dopant selected from the group consisting of Ce, Tb, Eu, Yb, Pr, Tm and Sm.
The method for producing an inorganic compound according to any one of claims 1 to 4, wherein the inorganic compound is a YAG phosphor. The method for producing an inorganic compound according to any one of claims 1 to 5, which comprises both a step of reacting the two or more kinds of metal oxide powders by a mechanochemical method and a step of removing the flux with an acid. The method for producing an inorganic compound according to any one of claims 1 to 6, wherein the power of the rotor is 0.1 kW / g or more with respect to the total amount of the raw material powder, and the rotor is rotated for 10 minutes or more. The method for producing an inorganic compound according to any one of claims 5 to 7 , wherein the amount of the flux added is 4% by mass or more with respect to the raw material powder. The method for producing an inorganic compound according to any one of claims 5 to 8 , wherein the proportion of the YAG phosphor contained in the product treated by the mechanochemical method is 3% by mass or more of the entire treated product.

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