TW201412943A - Method for producing beta-sialon, beta-sialon, and light-emitting device - Google Patents

Abstract

Provided are a method for producing beta-sialon, beta-sialon, and a light-emitting device with which it is possible to bring peak wavelength to within a range of greater than 545 nm but no more than 555 nm without reducing light-emission efficiency. The beta-sialon, in which Eu2+ is a solid solution in beta-sialon represented by the general formula Si6-zAlzOzN8-z, is produced by performing a mixing step S1 for adding, kneading, and homogenizing starting materials, and a firing step S2 for firing the post-mixing-step starting materials and obtaining beta-sialon. The mixing step S1 involves performing a primary mixing step S11 for mixing silicon nitride, aluminum nitride, and oxide such that 0.3 ≤ z ≤ 1.0, and a secondary mixing step S12 for mixing beta-sialon powder and one or both of europium oxide and europium salt with the starting materials after the primary mixing step S11. Moreover, one or both of aluminum oxide and silicon oxide are used as the oxide mixed in the primary mixing step S11.

Description

Method for manufacturing β-Sialon, β-Sialon and illuminating device

The present invention relates to a method for producing β-Sialon, a β-Sialon, and a light-emitting device. More specifically, the present invention relates to a method for producing a β-Silon in which Eu ^{2+ is} dissolved in β-Silon (SiAlON), a β-Sialon manufactured by the method, and a light-emitting device using the β-Sialon.

It is known that the β-sialon in which the divalent europium (Eu ²⁺ ) of the luminescent center is dissolved in β-Silon is excited by the light of a wide range of wavelengths from ultraviolet light to blue light (see Patent Documents 1 to 3). For example, paragraph 0015 of Patent Document 1 discloses a β-Sialon in which the composition of β-Sialon represented by the general formula: Si _6-Z Al _Z O _Z N _8-Z is obtained by making Z 0.24~ 0.42 and the Eu content was 0.05 to 0.25 at%, and the wave front wavelength was 535 nm.

Patent Document 2 discloses a β-Sialon by setting the lattice constant a of the β-Sialon crystal to 0.7605 to 0.7610 nm, the lattice constant c to 0.2906 to 0.2911 nm, and the Eu content to 0.4 to 2 mass%. The first transition metal content is set to 5 ppm or less to achieve high luminous efficiency and narrow band emission. Patent Document 3 discloses a β-Sialon having an average diffuse reflectance of 90% or more at a wavelength of 700 to 800 nm and a diffuse reflectance of 85% or more at a wavelength of a fluorescent wave front.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] International Publication No. 2006/121083

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2010-241995

[Patent Document 3] Japanese Laid-Open Patent Publication No. 2011-174015

In the conventional β-Sialon described in the above-mentioned Patent Documents 1 to 3, the wavelength of the fluorescence spectrum of the fluorescence spectrum when excited by light having a wavelength of 455 nm is 540 to 545 nm. In contrast, in recent years, a phosphor having a peak on the longer wavelength side than 545 nm has been required, and there has been a discussion on shifting the wavelength of the wave front of β-Sialon to the long wavelength side.

However, while maintaining the luminous efficiency necessary as β-Sialon, it is difficult to set the wave front wavelength to a longer wavelength side than 545 nm, and it has not been realized so far when excited by light having a wavelength of 455 nm, at more than 545 nm and 555 nm. The following wavelengths have a wavelength of β-Sylon. Further, the luminous efficiency necessary for β-Sialon is converted to an external quantum efficiency of 55% or more. Here, "external quantum efficiency" means the ratio of the number of fluorescent light-emitting photons to the number of excitation photons irradiated to β-sialon.

Here, the main object of the present invention is to provide a method for producing β-Sialon, a β-Sialon, and a light-emitting device, which can reduce the luminous efficiency and set the peak wavelength to a range of more than 545 nm and 555 nm or less.

The inventors of the present invention have been able to solve the aforementioned problems. As a result of intensive experimentation of the production of the wave front wavelength shift to the long wavelength side of the β-Silon, it was found that the production of β-Sialon by design change alone would cause a new problem of heterogeneous generation or interparticle sintering. This inter-particle sintering system causes lattice defects, which in turn causes a decrease in fluorescence characteristics.

The present inventors further explored and found that by limiting the z value in the general formula: Si _6-z Al _z OzN _8-z to 0.3 ≦ z ≦ 1.0 while being manufactured by a specific method, the luminous efficiency can be not lowered. The present invention has been achieved by shifting the peak wavelength to a longer wavelength side than 545 nm.

The method for producing β-Sialon according to the present invention comprises: a blending step of mixing and kneading a raw material to homogenize; and a calcining step of calcining the raw material after the blending step to obtain β-Sialon. In the foregoing blending step: a single blending step of blending tantalum nitride, aluminum nitride, and the like into a general formula: Si _6-z Al _z OzN _8-z (0.3≦z≦1.0) An oxide; and a secondary blending step of blending either or both of the β-Sialon powder and the cerium oxide and the cerium salt in the raw material after the primary blending step, the blending in the previous blending step Either or both of oxide-based alumina and cerium oxide, according to which Eu ^{2+ is} dissolved in a formula: Si _6-z Al _z O _z N _8-z (0.3≦z≦1.0) β-Sialon, to obtain a β-Silon having a peak wavelength of a fluorescence spectrum when excited by light having a wavelength of 455 nm of more than 545 nm and 555 nm or less.

It is preferable to blend 5 to 30% by mass of the aforementioned β-sialon powder with respect to 100% by mass of the raw material after the one-time mixing step.

Preferably, the total blending amount of the oxide, the cerium oxide and the cerium salt is any one of the cerium oxide and the cerium salt in the secondary blending step. The blending amount of the total amount of both or both is set to 0.33 to 0.50.

Preferably, the calcination step is carried out at a temperature of 1820 to 2050 ° C in a nitrogen gas atmosphere.

Preferably, the calcination step is performed by setting the gas pressure to 0.1 to 10 MPa.

In the method for producing β-Sialon according to the present invention, the particle size adjustment step may be performed after the calcination step, and the average particle diameter may be 30 μm or less by either or both of pulverization and classification.

In the method for producing β-Sialon according to the present invention, the heat treatment step of the β-Sialon after the calcination step or the particle size adjustment step may be maintained at 1300° C. or higher and the calcination temperature in the calcination step or lower. Under temperature conditions.

The method for producing β-Sialon according to the present invention may be subjected to an acid treatment step after the calcination step, the particle size adjustment step or the heat treatment step, comprising: an impregnation step of immersing β-sialon in an acid solution; and a washing step It cleans the acid solution remaining on the surface of the β-sialon after the aforementioned impregnation step.

The β-Sialon of the present invention is a β-Silone manufactured by the aforementioned method for producing β-Sialon, which is such that Eu ^{2+ is} dissolved in a general formula: Si _6-z Al _z O _z N _8-z (0.3 ≦z≦1.0) indicates β-Sialon, and when the wavelength of 455 nm is excited, the wavelength of the fluorescence spectrum of the fluorescence spectrum is greater than 545 nm and 555 nm or less.

Preferably, the Al content of the β-Sialon of the present invention is 2 to 8% by mass, the Eu content is 0.3 to 1% by mass, and the oxygen content is 0.5 to 4% by mass.

Preferably, the β-Sialon of the present invention uses a powder X-ray diffraction method to measure the diffraction ray intensity of a crystal phase other than β-sialon, relative to β-Sylon The diffraction radiation intensity of the (101) plane is 1% or less.

The light-emitting device of the present invention includes a light-emitting element and a phosphor mounted on a light-emitting surface of the light-emitting element, and the β-Sialon is used in part or all of the phosphor.

Preferably, the light-emitting element of the light-emitting device of the present invention is a light-emitting diode (LED).

According to the present invention, it is possible to stably produce β-sialon having a wave front wavelength of more than 545 nm and 555 nm or less while maintaining the external quantum efficiency as the luminous efficiency of 55% or more.

1‧‧‧Lighting device

2‧‧‧Lighting elements

3‧‧‧Fertior

4, 7‧‧‧ lead frame

5‧‧‧Encapsulated resin

6‧‧‧bonding leads

8‧‧‧ frame

Fig. 1 is a flow chart showing a manufacturing procedure of β-Sialon according to the first embodiment of the present invention.

Fig. 2 is a schematic view showing the configuration of a light-emitting device according to a second embodiment of the present invention.

Fig. 3 is a pictorial substitute photograph showing a scanning electron microscope (SEM) image of β-Sialon of Example 1.

4 is a pictorial substitute photograph showing a scanning electron microscope (SEM) image of β-Silon of Comparative Example 2.

[Formation of the Invention]

The embodiments for carrying out the invention will be described in detail below with reference to the accompanying drawings.

(First embodiment)

[β赛隆]

The β-Sialon system according to the first embodiment of the present invention dissolves Eu ²⁺ in a β-Sialon represented by the general formula: Si _6-z Al _z O _z N _8-z (0.3≦z≦1.0), and The wavelength of the fluorescence spectrum of the fluorescence spectrum when excited by light having a wavelength of 455 nm is greater than 545 nm and 555 nm or less.

If the z value of Si _6-z Al _z O _z N _8-z is less than 0.3, the wavelength of the fluorescent wave front will become lower than 545 nm. On the other hand, when the z value is more than 1.0, it becomes difficult to suppress the generation of the hetero phase and the sintering between the particles, and the external quantum efficiency of the luminescence intensity index is less than 55%. Therefore, the β-Sialon system of the present embodiment limits the z value to 0.3≦z≦1.0. Thereby, the fluorescence peak wavelength can be shifted to the longer wavelength side than 545 nm.

The β-Sialon of the present embodiment preferably has an Al content of 2 to 8% by mass, an Eu content of 0.3 to 1% by mass, and an oxygen content of 0.5 to 4% by mass based on the total mass. By setting the Al content, the Eu content, and the oxygen content to the above ranges, it is possible to specify the correct z value in the formula.

The β-Silon of the present embodiment is preferably a diffraction ray intensity of a crystal phase other than β-Sialon measured by a powder X-ray diffraction method, and a diffraction ray intensity of 1% with respect to the β-Sialon (101) plane. the following. When the diffraction ray intensity of the crystal phase other than β-Sialon is 1% or less, the content of the crystal phase other than β-Sialon is extremely small, and the β-Sialon crystal phase containing high purity is contained. In addition, even if the diffraction ray intensity of the crystal phase other than β-Sialon is more than 1% and the amorphous phase containing the unavoidable impurities or the crystal phase other than β-Sialon, there is no problem as long as the range of the characteristics is not lowered.

[Production method]

Next, the manufacturing method of the β-Sialon of the present invention is carried out. Description. Fig. 1 is a flow chart showing a method of manufacturing the β-Sialon of the present embodiment. As shown in Fig. 1, in the method for producing β-Sialon of the present embodiment, a blending step S1 is performed in which a kneading raw material is blended and homogenized, and a baking step S2 is performed in which the raw material after the blending step is fired. Into the resulting beta.

< blending step S1>

In the blending step S1, the blending is carried out in two stages. First, in one mixing step S11, any one of tantalum nitride and cerium oxide is blended in such a manner as to have the formula: Si _6-z Al _z O _z N _8-z (0.3≦z≦1.0) or Both with aluminum nitride and aluminum oxide.

Next, in the secondary blending step S12, the raw material blended in the primary blending step S11 is blended with either or both of the β-sialon powder and the cerium oxide and the phosphonium salt. The β-sialon powder blended at this time was used as a compound of the formula: Si _6-z Al _z O _z N _8-z (0.3≦z≦1.0).

The blending ratio of the β-sialon powder in the secondary blending step S12 is preferably 5 to 30% by mass based on 100% by mass of the raw material after the primary blending step. If the blending amount of the β-sialon powder is too small, the addition effect of the β-sialon powder cannot be sufficiently obtained. On the other hand, if the amount of the β-sialon powder is too large, the crystal grain growth of the β-sialon powder tends to be excessive, and the growth of the produced β-sialon particles tends to be small.

The blending ratio of any one or both of cerium oxide and cerium salt in the secondary blending step S12 (hereinafter referred to as cerium ratio) is preferably a total blending amount with respect to oxide, cerium oxide and cerium salt. It is set to be 0.33 to 0.50.

In the initial stage of the calcination step S2 described later, the oxide in the raw material forms a liquid phase, and Si ₃ N ₄ or AlN is dissolved in the liquid phase to precipitate β-Sialon. By raising the enthalpy ratio in the resulting liquid phase, the liquid phase formation temperature can be lowered and the firing temperature can be lowered. By the reduction in the firing temperature, the decomposition of the β-sialon powder blended in the secondary blending step S12 can be suppressed, and the formation of the lattice defects in the obtained β-Sialon can be suppressed, and the decrease in the fluorescence characteristics can be prevented. .

Furthermore, by increasing the enthalpy ratio, it is also possible to promote the solid solution in the β-Sialon and improve the fluorescence characteristics in the obtained Sialon. If the ruthenium ratio is too low, the effect of lowering the liquid phase formation temperature becomes insufficient, and it is difficult to perform low-temperature baking. On the other hand, if the ruthenium ratio is too high, even if the liquid phase formation temperature is lowered, the liquid phase may be excessively formed, and the composite oxide may remain as a hetero phase and cause a decrease in fluorescence characteristics.

In the mixing method of the aforementioned blending step S1 (primary blending step S11, secondary blending step S12), there is a dry mixing method in which an inert solvent which does not substantially react with each component of the raw material is used. A method of removing the solvent after wet mixing. The apparatus for mixing is not particularly limited, and a conventional apparatus such as a V-type mixer, a rolling mixer, a ball mill, or a vibration mill can be used.

In the method for producing β-Sialon according to the present embodiment, since the blending step is performed in two stages, generation of heterogeneous phase can be suppressed and occurrence of sintering between particles can be suppressed. Specifically, since the β-sialon powder is added in the secondary blending step S12, sintering between the particles in the firing step S2 described later can be suppressed. Thereby, the formation of lattice defects can be suppressed, and the decrease in the fluorescence characteristics of the obtained β-Sialon can be suppressed.

<Burning step S2>

In the baking step S2, the raw material after the blending step S1 is fired to obtain β-sialon. The container for storing the raw material in the firing step S2 is usually a material that does not react with the raw material when it is fired by using boron nitride or the like. Although the conditions of the baking step S2 can be appropriately selected depending on the composition of the raw material, etc., in order to prevent the incorporation of impurities during the firing step, it is preferred to adjust the calcination reaction in a nitrogen gas atmosphere. It is carried out in the range of 1820 to 2050 °C.

The firing temperature is preferably from 1900 to 1980 °C. The reason is that if the firing temperature is too low, it tends to be difficult to grow the crystal grains of β-Sialon. If it is too high, the amount of lattice defects generated during grain growth is increased, and lattice defects are absorbed. Visible light has a tendency to lower the fluorescence characteristics.

The baking step S2 is preferably carried out under the conditions of a gas pressure of 0.1 to 10 MPa. The reason for this is that if the gas pressure at the time of firing is too low, decomposition of the raw material nitride or the β-sialon powder previously contained in the raw material may occur, and if it is too high, the burden on the device may increase. In order to prevent the incorporation of impurities during the firing step, the firing step S2 is preferably carried out in a vacuum or in an inert gas atmosphere such as nitrogen or argon.

<granularity adjustment step>

In the method for producing β-Sialon according to the present embodiment, in order to achieve the uniformity of β-Sialon, it is preferable to perform a particle size adjustment step after the baking step S2, which is performed by either or both of pulverization and classification. The average particle diameter is set to 30 μm or less.

The method of pulverization is not particularly limited, and for example, the pulverized powder such as a ball mill, a vibration mill, and a jet mill is used for the fired β-Sialon. A method of breaking to a given particle size. Further, the method of classification is not particularly limited, but for example, only the sieved β-Sialon is passed through a sieve of 20 to 45 μm or less. The method of recycling.

<heat treatment step>

In the method for producing β-Sialon according to the present embodiment, it is preferred to subject the β-Sialon after the baking step S2 or the particle size adjusting step to a heat treatment step of maintaining the temperature at 1300° C. or higher and the firing step S2. Under the temperature conditions below the temperature. By performing this heat treatment step, a lattice defect existing in the β-Sialon and hindering the visible light emission or the second phase can be made to be in an acid-soluble state.

At this time, if the temperature at the heat treatment step is too low, the effect of the defect removal tends to be low, and if the temperature is too high, the effect is too high to be promoted. Further, the heat treatment step may be carried out in a gas selected from the group consisting of nitrogen gas, ammonia gas, hydrogen gas, and inert gas, or two or more mixed gas atmospheres, or in a vacuum.

The temperature and the treatment time in the heat treatment step are preferably such that the average diffusion reflectance of β-Silon at a wavelength of 650 to 800 nm is 10 to 50% lower than that before the heat treatment step. The reason for this is that if the decrease in the average diffuse reflectance due to the heat treatment step is less than 10%, the state change of the visible light ray-blocking factor becomes small, and the effect of improving the characteristics due to the treatment becomes small. Further, the reason is that if the decrease in the average diffuse reflectance is more than 50%, it is unsatisfactory due to the decomposition of the normal β-sialon crystal.

<acid treatment step>

In the method for producing β-Sialon according to the embodiment, it is preferably baked. The acid treatment step is performed after the step S2, after the particle size adjustment step or after the heat treatment step. Specifically, the acid treatment step is preferably carried out by: a dipping step of immersing β-sialon in an acid solution; and a washing step of washing the acid solution remaining on the surface of the β-sialon after the impregnation step. The acid treatment step is a step of dissolving and removing the luminescence hindrance factor which changes during the heat treatment step, and by performing this step, the fluorescence characteristics of the β-Sialon can be improved.

The acid used in the acid treatment step may be any one or a mixture of two or more of hydrofluoric acid, sulfuric acid, phosphoric acid, hydrochloric acid, and nitric acid, and these acids may be used in the form of an aqueous solution. In the method of carrying out the impregnation step, for example, a method in which the β-sialon after the heat treatment step is dispersed in the above-mentioned aqueous solution containing an acid and stirred for several minutes to several hours is used. The temperature of the acid in the impregnation step is not particularly limited, and may be appropriately selected from room temperature, heated to room temperature or higher, and 50 to 80 ° C. In order to remove the acid, the β-Sialon after the impregnation step is subjected to water washing after the acid is separated by a filter (washing step).

As described in detail above, in the β-Sialon of the present embodiment, the z value of the sialon represented by the general formula: Si _6-z Al _z O _z N _8-z is in the range of 0.3 to 1.0, and is carried out in two stages. The blending step and the addition of the β-sialon powder in the secondary blending step can shift the wavefront wavelength to a longer wavelength side than before without lowering the luminous efficiency. As a result, it is possible to realize β-sialon having a wave front wavelength of more than 545 nm and 555 nm or less while maintaining the external quantum efficiency as the luminous efficiency of 55% or more.

(Second embodiment)

Next, the light-emitting device according to the second embodiment of the present invention will be described. Fig. 2 is a schematic view showing the configuration of a light-emitting device of the embodiment. As shown in FIG. 2, the light-emitting device 1 of the present embodiment includes a light-emitting element 2 and a phosphor 3 mounted on a light-emitting surface of the light-emitting element, and the above-described first part is used in part or all of the phosphor 3 1 embodiment of the beta cello.

As the light-emitting element 2, various LEDs such as an ultraviolet light-emitting diode (UV-LED) and a blue light-emitting diode (blue LED), a phosphor lamp, and a laser diode (LD) can be used. It is preferably an LED. Further, in the case of the phosphor 3, only the above-described β-sialon according to the first embodiment may be used, but a red-emitting phosphor, an orange-emitting phosphor, a yellow-emitting phosphor, and a green light may be used in combination. Fluorescent body and blue luminescent phosphor. Thereby, the illuminating color as the illuminating means can be adjusted.

In the light-emitting device 1 of the present embodiment, the light-emitting element 2 is mounted on the lead frame 4, and the light-emitting element 2 is sealed in the frame 8 of the lead frame 4 by the sealing resin 5 obtained by dispersing the phosphor. The light-emitting element 2 is connected to the other lead frame 7 by the bonding wires 6.

In the light-emitting device 1 of the present embodiment, the light-emitting element 2 emits visible light from ultraviolet rays to violet, blue, and green light having a wavelength of 350 to 500 nm as excitation light, and irradiates the phosphor 3 composed of β-Sialon or the like. By the irradiation of the excitation light, the β-Sialon emits light having a peak in a wavelength region of more than 545 nm and 555 nm or less. Since the external quantum efficiency of the β-sialon used in the light-emitting device 1 of the present embodiment is 55% or more, the light-emitting device 1 of the present embodiment can have high luminous intensity.

[Examples]

Hereinafter, the effects of the present invention will be described by way of examples and comparative examples of the present invention.

(First embodiment)

In the first embodiment, β-Sialon was produced by the method shown below, and its characteristics were evaluated. The composition and evaluation results of the β-Sialon of the examples and the comparative examples are shown in Table 1 below.

The z value in the formula of β-Sialon shown in Table 1 is the value at the time of blending the raw materials, which is a target value. Further, in Table 1, in Example 1 and Comparative Example 2, in which the values of z are the same, although the Al content or the oxygen content of the composition analysis values are different, this is because a part of the raw material is volatilized in the firing step, or The phase remaining in the crystal which is completely dissolved in the β-Sialon is removed by the acid treatment in the subsequent heat treatment step or acid treatment step.

<fluorescence spectrum>

The wave front wavelength of the fluorescence spectrum shown in Table 1 was measured by the following method using a spectrophotometer (MCPD-7000 manufactured by Otsuka Electronics Co., Ltd.). First, each of the β-Sialon (hereinafter referred to as a sample) of the examples and the comparative examples was filled in a concave measuring tank to smooth the surface thereof, and an integrating sphere was attached. Secondly, The integrating sphere was introduced into the blue light having a wavelength of 455 nm by the Xe lamp of the light-emitting source by the optical fiber. The sample was irradiated with the blue light as an excitation source, and the fluorescence of the sample and the spectrum of the reflected light were measured by a spectrophotometer (MCPD-7000 manufactured by Otsuka Electronics Co., Ltd.). The wave front wavelength was obtained from the obtained fluorescence spectrum.

<Diffraction Ray Intensity>

The diffraction ray intensity shown in Table 1 is obtained by measuring the intensity of the diffraction ray of the (101) plane by the powder X-ray diffraction method, and calculating the diffraction ray intensity of the (101) plane of the β-Silon as 100%. . In addition, "no out of phase" shown in Table 1 means that the intensity of the diffraction ray with respect to the surface of the β-Sialon (101) is 0.0%.

<Average particle size>

The average particle diameter shown in Table 1 is transmitted by laser diffraction using a particle size distribution measuring device. The scattering method performed 50% of the particle diameter (D50) in the integrated fraction of the volume basis obtained by the particle size distribution measurement.

<Al, Eu and oxygen content in the composition analysis value>

The values of Al and Eu in the compositional analysis values shown in Table 1 were obtained by dissolving the powder of each β-Sialon of the examples and the comparative examples by an alkali dissolution method, and then using an ICP emission spectroscopic analyzer (Rigaku Co., Ltd.) Determination of Al content and Eu content by CIROS-120). The value of oxygen in the compositional analysis values shown in Table 1 is the oxygen content measured by an oxygen-nitrogen analyzer (EMGA-920, manufactured by Horiba, Ltd.).

<External quantum efficiency>

A standard reflection plate (Spectralon manufactured by Labsphere) with a reflectance of 99% was set in the sample portion, and the wavelength was measured to be wavelength. The spectrum of the excitation light of 455 nm calculates the number of excitation photons (Qex) from the spectrum in the wavelength range of 450 to 465 nm. The measurement target is provided with β-Sialon, and the β-Silon is irradiated with blue light having a wavelength of 455 nm to calculate the number of photons (Qref) and the number of fluorescent photons (Qem) of the excited reflected light from the obtained spectral data. .

The number of excitation-reflected photons is in the same wavelength range as the number of excitation photons, and the number of fluorescent photons is calculated in the range of 465 to 800 nm. The external quantum efficiency (=Qem/Qex×100) was obtained from the number of photons of the three types obtained.

[Example 1]

According to the method for producing β-Sialon according to the first embodiment, the tantalum nitride and the aluminum nitride are blended in such a manner as to have a general formula: Si _6-z Al _z O _z N _8-z (z=0.5). The oxide was used to produce the β-Sialon of Example 1.

<Manufacture of β-sialon powder used in the secondary blending step>

First, the β-sialon powder used in the secondary blending step was produced by the methods and conditions shown below. Raw material used: 95.43% by mass of α-type tantalum nitride powder (SN-E10 grade: oxygen content 1.0% by mass) and 3.04% by mass of aluminum nitride powder manufactured by Tokuyama Co., Ltd. (E grade) : an oxygen content of 0.9% by mass), 0.74% by mass of alumina powder (TM-DAR grade) manufactured by Daming Chemical Co., Ltd., and 0.79 mass% of ruthenium oxide powder (RU grade) manufactured by Shin-Etsu Chemical Co., Ltd.

These raw materials were mixed by a V-type mixer (S-3 manufactured by Tsutsui Chemical Instruments Co., Ltd.), and in order to remove agglomerates, they were separated by a sieve of 500 μm. Recycling. Recycled beta sialon powder The raw material of the last is filled in a cylindrical boron nitride container (N-1 grade made by Electric Chemical Industry Co., Ltd.) with a lid, and is heated in a pressurized nitrogen gas atmosphere of 0.8 MPa in an electric furnace of a carbon heater. The sample was subjected to a calcination treatment at 2000 ° C for 15 hours to obtain β-Sialon.

The resulting β-Saron was broken by the hands of a clean rubber glove. The disintegrated β-Sialon was pulverized by a supersonic jet pulverizer (PJM-80SP manufactured by Pneumatic Industries, Japan). The pulverization conditions were such that the sample supply rate was 50 g/min, and the pulverization air pressure was set to 0.3 MPa. The obtained pulverized powder was used as a β-sialon powder used as a raw material in the secondary blending step.

<Method of manufacturing β-Sialon>

Next, in the case of the raw material, the α-type tantalum nitride powder (SN-E10 grade: oxygen content 1.0 mass%) manufactured by Ube Hiroshi Co., Ltd., which is 78.45 mass%, and the nitrogen produced by Tokuyama Co., Ltd. of 3.51 mass% are used. Aluminum oxide powder (E grade: oxygen content: 0.9% by mass), 3.39 mass% of alumina powder (manufactured by Daming Chemical Co., Ltd.), and 1.74% by mass of yttrium oxide powder manufactured by Shin-Etsu Chemical Co., Ltd. (RU) Grade) and 12.91% by mass of the raw material β-sialon powder produced by the above methods and conditions.

These raw materials were mixed by a V-type mixer (S-3 manufactured by Tsutsui Chemical Instruments Co., Ltd.), and all of them were passed through a sieve of 500 μm mesh to remove aggregates. At this time, the blending ratio is in the formula of β-Sialon: Si _6-z Al _z O _z N _8-z , except that the cerium oxide and the raw material Sialon are designed to have z=0.5. Further, the ratio of the cerium ratio (Eu ₂ O ₃ /oxide of Table 1) to the oxide was 0.34% by mass.

Next, the raw material of the β-Sialon which was all sieved and recovered was subjected to a baking step. In the calcination step, the raw material was filled in a cylindrical boron nitride container with a lid, and was subjected to an electric furnace of a carbon heater at 1900 ° C for 15 hours in a pressurized nitrogen gas atmosphere of 0.8 MPa. Heat treatment. The β-Sialon obtained through the firing step is broken by a person wearing a clean rubber glove.

The disintegrated β-Sialon was passed through a supersonic jet pulverizer, and the pulverization treatment was carried out under the conditions of a sample supply speed of 50 g/min and a pulverization air pressure of 0.5 MPa, and the classification by the air flow classifier was carried out by the particle size distribution adjustment step. Process to remove micronized powder. At this time, the classification conditions were such that the sample supply rate was 50 g/min, the classification air volume was 2.0 m/m ³ , and the number of revolutions was 2000 rpm.

The heat-treated step of the fragmented and classified β-Sialon is performed. In the heat treatment step, the obtained pulverized powder is filled in a cylindrical boron nitride container with a lid, and is subjected to an electric furnace of a carbon heater at 1500 ° C for 8 hours in an atmospheric pressure argon gas atmosphere. Heat treatment. The color of the β-Sialon before the heat treatment step is pale yellow, but the color of the β-sialon powder after the heat treatment step changes to dark green.

Further, an acid treatment step is performed on the β-Sialon after the heat treatment step. In the acid treatment step, β-sialon was immersed in a mixed acid (liquid temperature: 80 ° C) in which 50% by mass of hydrofluoric acid and 70% by mass of nitric acid were mixed at a mass ratio of 1:1 for 1 hour. Thereafter, the β-sialon immersed in the mixed acid was filtered, washed with water, and dried.

Thereby, Eu ^{2+ is} dissolved in the formula: Si _6-z Al _z O _z N _8-z (z = 0.50), that is, Si _5.5 Al _0.5 O _0.5 N _{7.5 is} shown as β sialon. The β-Sialon of Example 1 was formed. The β-Sialon of Example 1 had an Al content of 2.8% by mass, an Eu content of 0.8% by mass, an oxygen content of 1.589% by mass, and an average particle diameter of 21.86 μm.

In the Sialon of Example 1, when the wavelength of 455 nm is excited, the fluorescence spectrum has a wave front wavelength of 552 nm and an external quantum efficiency of 66%, which does not lower the luminous efficiency and allows the wave front wavelength to be greater than 545 nm and 555 nm or less. . Further, the β-Sialon of Example 1 was confirmed to be a diffraction ray intensity of a crystal phase other than β-Sialon measured by a powder X-ray diffraction method, and a diffraction ray with respect to the β-Sialon (101) plane. The strength is 0% and does not contain a heterogeneous phase.

(Example 2)

As shown in Table 1, except that the raw material was blended so that the z value became 0.7, the β-Sialon of Example 2 was produced by the same method and conditions as those of the above-described Example 1 of β-Sialon. The β-Sialon of Example 2 has the same wave front wavelength and external quantum efficiency as the β-Sialon of Example 1.

(Example 3)

As shown in Table 1, except that the raw material was blended so that the z value became 0.3, the β-Sialon of Example 3 was produced by the same method and conditions as those of the above-described Example 1 of β-Sialon. The β-Sialon of Example 3 has a lower wavelength and external quantum efficiency than the β-Sialon of Example 1, but has no problem.

(Example 4)

As shown in Table 1, except that the raw material was blended so that the z value became 1.0, the β-Sialon of Example 4 was produced by the same method and conditions as those of the above-described Example 1 of β-Sialon. The β-Sialon of Example 4 is compared to Example 1 The β-Sialon has a wavefront wavelength that is high and the external quantum efficiency is reduced, but there is no problem.

(Example 5)

As shown in Table 1, except that the raw material was blended so that the z value was 0.7 and the ruthenium ratio was 0.27% by mass, the β of Example 5 was produced by the same method and conditions as those of the above-described Example 1 of β-Sialon. Saone. The β-Sialon of Example 5 has a wave front wavelength of more than 545 nm and an external quantum efficiency of 55%.

(Comparative Example 1)

As shown in Table 1, except that the raw material was blended so that the z value became 0.2, the β-Sialon of Comparative Example 1 was produced by the same method and conditions as those of the above-described Example 1 of β-Sialon. The β-Sialon of Comparative Example 1 has a wave front wavelength of 541 nm and is equivalent to the conventional one, and the external quantum efficiency is also less than 55%.

(Comparative Example 2)

As shown in Table 1, β-Silon of Comparative Example 2 was produced in the same manner and under the same conditions as in the above-described Example 1 of β-Silon except that the raw material was not used. In the β-Sialon of Comparative Example 2, the wave front wavelength was the same as that of the β-Sialon of Example 1, but the external quantum efficiency was 44%, which was significantly lower than that of the β-Sialon of Example 1.

(Comparative Example 3)

As shown in Table 1, except that the raw material was blended so that the z value was 1.2 and the ruthenium ratio was 0.41% by mass, the β of Comparative Example 3 was produced by the same method and conditions as those of the above-described Example 1 of β-Sialon. Saone. The β-Sialon of Comparative Example 3 shifted the wave front wavelength to the longer wavelength side than the β-sialon of Example 1 and was larger than 555 nm, and the external quantum efficiency did not reach 55%.

From the above results, Comparative Examples 1 and 3 in which the z value deviated from the range of 0.3 to 1.0 had a wave front wavelength of 545 nm or less or more than 555 nm, and the external quantum efficiency was also less than 55%.

3 is a scanning electron microscope (SEM) image of β-Sialon of Example 1, and FIG. 4 is a scanning electron microscope (SEM) image of β-Sialon of Comparative Example 2. As shown in FIG. 3 and FIG. 4, the β-Sialon of Comparative Example 2 in which the raw material was not used in the Sialon powder had a smaller particle size than the β-Sialon of Example 1. In contrast, the β-Sialon of Example 1 in which the β-sialon powder was added to the raw material had a large short diameter and a structure composed of columnar particles having the same particle size, and as a result, good fluorescence characteristics were obtained. .

(Second embodiment)

In the second embodiment, each of the above-described examples and comparative examples of β-sialon was mixed with a sealing resin made of polyfluorene oxide, and was mounted on the surface of a light-emitting element of a blue light-emitting LED. And use this LED to make a lighting device.

As a result, the illuminating device of the β-Sialon of Examples 1 to 5 was used, and the luminescent color of the phosphor was shifted to a longer wavelength side than the conventional β-Silon. In contrast, the illumination device of the β-Sialon of Comparative Examples 1 to 3 was used because the emission wavelength of the phosphor was the same as that of the conventional β-Silon, or the luminescence intensity thereof was less than 55%, so that it was used in Examples 1 to 5. The lighting device of the β-Sialon is darker.

Claims (13)

A method for producing β-Sialon, comprising: a blending step of mixing and kneading a raw material to homogenize; and a calcining step of calcining the raw material after the blending step to obtain β-Sialon, the blending step The middle system is carried out: a mixing step of blending tantalum nitride, aluminum nitride and an oxide in such a manner that it becomes a general formula: Si _6-z Al _z OzN _8-z (0.3≦z≦1.0); a secondary blending step of blending either or both of the β-Sialon powder and the cerium oxide and the cerium salt in the raw material after the primary blending step, the oxide oxidized in the primary blending step Any one or both of aluminum and cerium oxide to dissolve Eu ²⁺ in β sialon represented by the general formula: Si _6-z Al _z O _z N _8-z (0.3≦z≦1.0) The peak wavelength of the fluorescence spectrum when excited by light having a wavelength of 455 nm is obtained as β-sialon having a wavelength of more than 545 nm and 555 nm or less. The method for producing β-Sialon according to the first aspect of the patent application, wherein the above-mentioned secondary blending step is blended with 5 to 30% by mass of the aforementioned β-sialon powder with respect to 100% by mass of the raw material after the one-time mixing step. . The method for producing β-Sialon according to claim 1 or 2, wherein the total blending amount of the oxide, the cerium oxide and the cerium salt is the cerium oxide and the cerium salt in the secondary admixing step. The blending amount of either or both is set to 0.33 to 0.50. For example, the manufacturer of β赛隆, which is one of the patent scopes 1 to 3 In the method, the calcination step is carried out at a temperature of 1820 to 2050 ° C in a nitrogen gas atmosphere. The method for producing β-Sialon according to any one of claims 1 to 4, wherein the calcination step is performed by setting the gas pressure to 0.1 to 10 MPa. The method for producing β-Sialon according to any one of claims 1 to 5, wherein after the calcination step, a particle size adjustment step is performed, wherein the average particle is obtained by either or both of pulverization and classification. The diameter is set to 30 μm or less. The method for producing β-Sialon according to any one of claims 1 to 6, wherein the step of heat-treating the β-Sialon after the calcination step or after the particle size adjustment step is maintained at 1300° C. or higher and The temperature is lower than the firing temperature in the baking step. The method for producing β-Sialon according to Item 7 of the patent application, wherein the calcination step, the particle size adjustment step or the heat treatment step is followed by an acid treatment step having an impregnation step of immersing β-sialon in an acid In the solution; and a washing step, which washes the acid solution remaining on the surface of the β-sialon after the aforementioned impregnation step. A β-Sialon manufactured by the method for producing β-Sialon according to any one of claims 1 to 8 which is capable of solid-solving Eu ²⁺ in the formula: Si _6-z Al _z O _z N _8-z (0.3≦z≦1.0) indicates β-Sialon, and when the wavelength of 455 nm is excited, the wavelength of the fluorescence spectrum of the fluorescence spectrum is greater than 545 nm and 555 nm or less. For example, the β-Sialon of claim 9 has an Al content of 2 to 8% by mass, an Eu content of 0.3 to 1% by mass, and an oxygen content of 0.5 to 4% by mass. For example, the β-Sialon of claim 9 or 10, wherein the diffraction ray intensity of the crystal phase other than β-sialon measured by the powder X-ray diffraction method, the diffraction ray relative to the β-Silon (101) plane The strength is 1% or less. A light-emitting device comprising a light-emitting element and a phosphor mounted on a light-emitting surface of the light-emitting element, and a part or all of the phosphor is a β-Seilon according to any one of claims 9 to 11. The illuminating device of claim 12, wherein the illuminating element is a light emitting diode.