KR20100071921A - Fine magnesium oxide powder and preparation thereof - Google Patents

Abstract

PURPOSE: A magnesium oxide fine powder is provided to emit UV light having peak wavelength at 200-300nm and to industrially manufacture the magnesium oxide fine powder. CONSTITUTION: A method for manufacturing magnesium oxide fine powder containing halogen comprises a step of contacting magnesium vapor and oxide-containing gas under the presence of gas having 0.001-500 g of halogen based on 1kg of magnesium vapor. The halogen is at least a kind of halogen selected from the group of fluorine and chlorine. The fine powder is a hexahedron of primary particle. The fine powder is excited by electronic beam.

Description

Magnesium oxide fine powder and its manufacturing method {FINE MAGNESIUM OXIDE POWDER AND PREPARATION THEREOF}

The present invention relates to a magnesium oxide fine powder, particularly a magnesium oxide fine powder which emits ultraviolet light having a peak wavelength in a range of 200 to 300 nm when excited by an electron beam, and a method for producing the same.

An AC plasma display panel (hereinafter also referred to as an AC PDP) generally includes a front plate and a back plate that are disposed to face each other with a discharge space filled with discharge gas therebetween. The front plate consists of a front glass substrate, a pair of discharge electrodes formed on the front glass substrate, a dielectric layer formed to cover the discharge electrodes, and a dielectric protective layer formed on the surface of the dielectric layer. The back plate consists of a back glass substrate, an address electrode formed on the back glass substrate, a partition wall for partitioning the discharge space, and red, green, and blue phosphor layers formed on the surface of the region partitioned by the partition wall.

Generally as a discharge gas, the mixed gas of xenon gas and neon gas is used.

As the material of the dielectric protective layer, magnesium oxide having a high secondary electron emission coefficient and excellent sputter resistance is widely used.

In an AC PDP, when a voltage is applied to the discharge electrode of the front plate, ions and electrons present in the discharge gas collide with the dielectric protective layer, and the dielectric protective layer emits secondary electrons, and the emitted secondary electrons are ionized. By repeating the process of colliding with an undischarged discharge gas atom and ionizing the discharge gas atom, charged particles in the discharge space are increased to start discharge. By the ultraviolet light generated by the discharge, the phosphors constituting the phosphor layer of the back plate are excited to emit blue, green and red visible light emitted from the front plate to display an image.

In the AC type PDP which displays an image by such a mechanism, with high definition of the image, shortening the time until the discharge is started after applying a voltage to the discharge electrode of the front panel, reducing the so-called discharge delay It becomes important.

Patent Document 1 describes a method for reducing the discharge delay of an AC type PDP, wherein the dielectric protective layer is excited by an electron beam to emit ultraviolet light having a peak wavelength in a range of 200 to 300 nm (cathode luminescence emission). The present invention discloses forming magnesium oxide crystals. According to this patent document 1, the magnesium oxide crystal which emits cathode luminescence can trap an electron for a long time by the energy level corresponding to the peak wavelength of the ultraviolet light which emits by cathode luminescence, and this electron By taking out by the electric field, the initial electrons necessary for the start of discharge are obtained, so that the discharge delay is reduced. That is, Patent Document 1 describes that magnesium oxide crystals that emit cathode luminescence act as priming particle emitting materials. Moreover, according to the data described in FIG. 7 of this patent document 1, the magnesium oxide crystal which emits cathode luminescence is a magnesium oxide crystal synthesized by the vapor phase oxidation method with a particle diameter of 2000 Angstroms or more.

Patent Document 2 discloses a method of reducing the discharge delay of an AC PDP, wherein a dielectric protective layer is excited by a thin film magnesium oxide layer formed by vapor deposition or sputtering with an electron beam and has a peak in a range of 200 to 300 nm. Disclosed is a structure in which a crystal magnesium oxide layer composed of magnesium oxide crystals which emits ultraviolet light having a wavelength is laminated. In addition, also in the data described in FIG. 8 of this patent document 2, cathode luminescence emission is seen in magnesium oxide crystals synthesized by vapor phase oxidation with a particle diameter of 2000 angstrom or more.

Patent document 3 mixes the magnesium oxide crystal | crystallization which excites by an electron beam and emits the ultraviolet light which has a peak wavelength in the range whose wavelength is 200-300 nm to the fluorescent substance which comprises a fluorescent substance layer as a secondary electron emission material, Or it is described that the discharge delay of AC type PDP is improved by laminating | stacking the layer which consists of magnesium oxide crystals on the surface of the side which contact | connects the discharge space of a fluorescent substance layer. Moreover, also in the data described in FIG. 7 of this patent document 3, cathode luminescence emission is seen in the magnesium oxide crystal synthesize | combined by the vapor phase oxidation method whose particle diameter is 2000 angstrom or more.

PTL 4 describes the use of halogen-containing magnesium oxide crystals containing 1 to 10000 ppm of halogen as the priming particle releasing material of the AC type PDP. Patent Document 4 describes that the halogen-containing magnesium oxide crystals preferably have an average particle diameter in the range of 0.05 to 20 µm. Patent Document 4 describes a method for producing a halogen-containing magnesium oxide crystal by mixing, firing and pulverizing the magnesium oxide crystal and a halogen-containing substance.

Patent Document 1: Japanese Unexamined Patent Publication No. 2006-59779

Patent Document 2: Japanese Unexamined Patent Publication No. 2006-59780

Patent Document 3: Japanese Unexamined Patent Publication No. 2008-66176

Patent Document 4: Japanese Unexamined Patent Publication No. 2008-282623

As disclosed in Patent Documents 1 and 2, in order to reduce the discharge delay of the AC type PDP, the dielectric protective layer is excited by an electron beam to emit ultraviolet light having a peak wavelength in the range of 200 to 300 nm. Forming with magnesium oxide crystals is effective. On the other hand, in the AC type PDP, in order to extract visible light from the front plate, it is preferable that the magnesium oxide crystal layer used as the material of the dielectric protective layer has high visible light transmittance. Moreover, it is desired that magnesium oxide crystals used as a secondary electron emitting material to be mixed with the phosphors constituting the phosphor layer or used as a secondary electron emission material for forming a layer laminated on the surface of the side in contact with the discharge space of the phosphor layer are desired. However, the magnesium oxide crystals which are considered to emit cathode luminescence light described in Patent Documents 1 to 3 have a problem that the visible light transmittance is low because the particle size is larger than 2000 angstroms (200 nm).

On the other hand, Patent Document 4 describes fine halogen-containing magnesium oxide crystals having an average particle diameter of 0.05 µm (50 nm). However, according to a study by the present inventors, when firing a mixture of magnesium oxide crystals and a halogen-containing substance, magnesium oxide crystals are sintered at the time of firing, and coarse particles are easily produced, and fine halogen-containing magnesium oxide powder is obtained. It turned out not to be lost.

Accordingly, an object of the present invention is to provide a fine halogen-containing magnesium oxide powder that emits ultraviolet light having a peak wavelength in the range of 200 to 300 nm when excited by an electron beam, and a method for producing the same.

MEANS TO SOLVE THE PROBLEM This inventor uses the method of oxidizing magnesium by contacting magnesium vapor and an oxygen containing gas in the gas atmosphere in which halogen, such as fluorine and chlorine, exists in the range of 0.01-500 g with respect to 1 kg of magnesium vapor. A fine halogen-containing magnesium oxide powder containing in the range of 0.001 to 10 mass% and having a BET specific surface area in the range of 34 to 350 m 2 / g, that is, an average particle diameter of 5 nm or more and less than 50 nm can be obtained. When the halogen-containing magnesium oxide fine powder was excited by an electron beam, it was confirmed that it was emitted, and it confirmed that light of ultraviolet light which has a peak wavelength in the range of wavelength 200-300 nm was completed, and this invention was completed.

Accordingly, the present invention provides magnesium halide fine powder containing magnesium vapor and oxygen-containing gas, in a gas atmosphere in which halogen is present in an amount ranging from 0.01 to 500 g per 1 kg of magnesium vapor. Is on the way.

In the method for producing a halogen-containing magnesium oxide fine powder of the present invention, the halogen is preferably at least one halogen selected from the group consisting of fluorine and chlorine.

This invention also exists in the halogen-containing magnesium oxide fine powder in which halogen is contained in 0.001-10 mass%, and BET specific surface area is 34-350 m <2> / g.

Preferred embodiments of the halogen-containing magnesium oxide fine powder of the present invention are as follows.

(1) Halogen is fluorine and / or chlorine.

(2) The particle shape of a primary particle is a cube.

(3) It is excited by an electron beam and emits the ultraviolet light which has a peak wavelength in the range of wavelength 200-300 nm.

The present invention also exists in a dielectric protective layer of an alternating current plasma display panel comprising the halogen-containing magnesium oxide fine powder of the present invention.

The present invention also exists in the phosphor layer of an AC plasma display panel containing the halogen-containing magnesium oxide fine powder of the present invention.

This invention also exists in the secondary electron emission layer laminated | stacked on the surface of the side which contact | connects the discharge space of the phosphor layer of an AC plasma display panel which consists of the halogen-containing magnesium oxide fine powder of the said invention.

Although the halogen-containing magnesium oxide fine powder of this invention is excited by an electron beam and emits the ultraviolet light which has a peak wavelength in the range of wavelength 200-300 nm, it is excited by the conventional electron beam and peaks in the range which is 200-300 nm wavelength. Compared with the magnesium oxide powder which emits ultraviolet light having a wavelength, the particle size is small and the visible light transmittance is high. For this reason, the AC type PDP provided with the dielectric protective layer formed using the halogen-containing magnesium oxide fine powder of the present invention has improved discharge characteristics such as discharge delay and a dielectric formed using conventional magnesium oxide powder. The luminance is improved as compared with an AC type PDP provided with a protective layer. Moreover, AC type PDP provided with the dielectric protective layer formed using such a halogen-containing magnesium oxide fine powder of this invention uses the conventional magnesium oxide powder with big particle diameter which excites an electron beam and emits ultraviolet light. The discharge start voltage can be lowered than that of the AC type PDP provided with the formed dielectric protective layer. In addition, an AC type PDP in which the halogen-containing magnesium oxide fine powder of the present invention is mixed with a phosphor to form a phosphor layer, or a layer made of the magnesium oxide fine powder of the present invention is laminated on the surface of the phosphor layer in contact with the discharge space. AC type PDPs also have improved discharge characteristics such as discharge delays and high luminance.

Moreover, by using the manufacturing method of the halogen containing magnesium oxide fine powder of this invention, it becomes possible to industrially advantageously manufacture said halogen containing magnesium oxide fine powder.

The halogen-containing magnesium oxide fine powder of this invention contains halogen in 0.001-10 mass%. The content of the halogen is preferably in the range of 0.01 to 10% by mass, more preferably in the range of 0.03 to 5% by mass, still more preferably in the range of 0.03 to 3% by mass, particularly preferably in the range of 0.1 to 1% by mass. Range. The halogen contained in the halogen-containing magnesium oxide fine powder of the present invention may be any one of fluorine, chlorine, bromine and iodine, or may be two or more kinds. The halogen is preferably fluorine and chlorine, more preferably fluorine.

The halogen-containing magnesium oxide fine powder of the present invention has a BET specific surface area of 34 m 2 / g or more, preferably 34 to 350 m 2 / g, more preferably 48 to 350 m 2 / g, further preferably Preferably it is in the range of 55 to 350 m 2 / g, and the average particle diameter obtained from the BET specific surface area is less than 50 nm, preferably in the range of 5 to 49 nm, more preferably in the range of 5 to 35 nm, more preferably Is a very fine powder in the range of 5 to 30 nm.

In addition, an average particle diameter is the value computed using following formula (I).

D = A / (S × ρ) ... (I)

In formula (I), D is the average particle diameter, A is the surface coefficient (= 6), S is the BET specific surface, and ρ is the true density of magnesium oxide.

The halogen-containing magnesium oxide fine powder of the present invention is excited by an electron beam to emit ultraviolet light having a peak wavelength in the wavelength range of 200 to 300 nm (preferably in the range of 230 to 250 nm, especially around 240 nm). Has characteristics. It is preferable that the halogen-containing magnesium oxide fine powder of this invention consists of primary particle of a dispersed state. It is preferable that the particle shape of a primary particle is a cube.

Next, the manufacturing method of the halogen-containing magnesium oxide fine powder of this invention is demonstrated. In the present invention, halogen is contained by contacting magnesium vapor with an oxygen-containing gas in a gas atmosphere in which halogen is present in an amount in the range of 0.01 to 500 g, preferably in the range of 0.1 to 500 g, to 1 kg of magnesium vapor. Magnesium oxide fine powder is prepared. Specifically, the halogen-containing magnesium oxide fine powder is produced by contacting magnesium vapor with an oxygen-containing gas while supplying the halogen-containing gas such that the amount of halogen is within the above range. EMBODIMENT OF THE INVENTION Hereinafter, the manufacturing method of the halogen containing magnesium oxide fine powder of this invention is demonstrated, referring an accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of an example of the magnesium oxide fine powder manufacturing apparatus which can be advantageously used for the manufacturing method of the halogen-containing magnesium oxide fine powder of this invention.

In Fig. 1, the apparatus for producing magnesium oxide fine powder includes a magnesium vapor jet outlet 11 on the upper side, and a metal magnesium melt evaporator 10 having a metal magnesium inlet 12 and a dilution gas inlet 13 on the side. And a magnesium oxide oxidizing device 14 connected to the magnesium vapor jet port 11 at the lower part, provided with an oxygen-containing gas jet port 15 at the side, and provided with a magnesium oxide fine powder outlet port 16 at the upper part. Examples of the dilution gas introduced from the dilution gas introduction port 13 include helium gas, neon gas, argon gas, krypton gas, xenon gas, and radon gas. Examples of the oxygen-containing gas introduced from the oxygen-containing gas injection port 15 include oxygen and air.

In the magnesium oxide fine powder production apparatus of FIG. 1, the metal magnesium injected from the metal magnesium inlet 12 is heated and melted in the metal magnesium melt evaporator 10, and the resulting molten magnesium 1 is further heated to obtain magnesium vapor. Is generated. The produced magnesium vapor is introduced into the magnesium oxide device 14 through the magnesium vapor jet port 11 together with the diluent gas introduced from the dilution gas inlet port 13. In the magnesium oxidation apparatus 14, a halogen-containing gas is introduced such that halogen is present in an amount in the above range, and the oxygen-containing gas introduced from the magnesium vapor and the oxygen-containing gas injection port 15 is under a gas atmosphere in which halogen is present. Contact is carried out, and magnesium is oxidized while introducing halogen to produce halogen-containing magnesium oxide fine powder (2). The BET specific surface area, ie, the particle size, of the halogen-containing magnesium oxide fine powder to be produced is determined in the cross-sectional area of the magnesium vapor jet port 11, the amount of magnesium vapor or oxygen-containing gas introduced into the magnesium oxidizing device 14, and the magnesium oxidizing device 14. It can be controlled arbitrarily by changing the contact position of the magnesium vapor of and the oxygen-containing gas. The halogen-containing magnesium oxide fine powder 2 produced in the magnesium oxide device 14 passes through the magnesium oxide fine powder outlet 16 and is recovered and stored after cooling by a heat exchanger (not shown) or the like. Since the obtained halogen-containing magnesium oxide fine powder is highly active and may adsorb | suck carbon dioxide and water in air during storage, you may refire at 500-1100 degreeC before shipment.

As a method of introducing a halogen-containing gas into the magnesium oxidizing apparatus 14, a halogen-containing gas is supplied to the dilution gas inlet 13, and the halogen-containing gas is introduced into the magnesium oxidizing apparatus 14 together with the magnesium vapor or the diluting gas. A method of supplying a halogen-containing gas to the oxygen-containing gas injection port 15, and introducing the halogen-containing gas together with the oxygen-containing gas into the magnesium oxidizing device 14, and a halogen-containing gas inlet to the magnesium oxidizing device 14 The method of any of the methods which form and introduce | transduce into a magnesium-oxidation apparatus by the halogen containing gas alone can be used.

The halogen-containing gas introduced into the magnesium oxidation device 14 is a gas containing one kind or two or more kinds of halogens (fluorine, chlorine, bromine and iodine). The halogen-containing gas is preferably a gas containing fluorine and / or chlorine, and more preferably a fluorine-containing gas.

Examples of the fluorine-containing gas include hydrogen fluoride, nitrogen trifluoride, sulfur hexafluoride, sulfuryl fluoride, ammonium fluoride, hydrofluorocarbon (HFC), perfluorocarbon (PFC), hydrofluoroether, perfluoroketone, and the like. And gas produced by evaporating or pyrolysing a gaseous fluorine-containing compound or a liquid or solid fluorine-containing compound at normal temperature by heating.

Specific examples of hydrofluorocarbons include difluoromethane, difluoroethane, 1,1,1,2-tetrafluoroethane, pentafluoroethane, heptafluoropropane, dihydrodecafluoropentane, and the like. Can be. Specific examples of the perfluorocarbons include perfluoromethane and perfluoroethane. Specific examples of the hydrofluoroethers include methoxy-1,1,1,2,2-tetrafluoroethane, methoxy-nonafluorobutane, ethoxy-nonafluorobutane, and the like. Specific examples of the perfluoroketone include pentafluoroethyl-heptaopropyl ketone and the like.

Examples of the chlorine-containing gas include dye-containing compounds of gas at room temperature, such as dyeing, methylene chloride, chloroform, carbon tetrachloride, 1,1,1-trichloroethane, 1,1,2-trichloroethane, tetrachloroethylene and tea chloride. And gases produced by heating or pyrolysing liquid or solid chlorine-containing compounds at room temperature, such as oyl and sulfuryl chloride.

Examples of the gas containing fluorine and chlorine include chlorofluorocarbons such as dichlorofluoromethane and hydrochlorofluorocarbons such as chloropentafluoroethane.

The halogen-containing magnesium oxide fine powder of the present invention is the discharge material of the phosphor layer of the AC-type PDP, the secondary electron emission material mixed with the material for forming the dielectric protective layer of the AC-type PDP, the phosphor constituting the fluorescent layer of the AC-type PDP, It can be used as a material for forming the secondary electron emission layer laminated on the surface of the side in contact with the space.

The dielectric protective layer made of the halogen-containing magnesium oxide fine powder of the present invention can be formed by applying and drying a dispersion liquid in which the halogen-containing magnesium oxide fine powder is dispersed in a dispersion medium on a dielectric layer. Alcohol, such as ethanol or isopropyl alcohol, can be used as a dispersion medium of a dispersion liquid.

The dielectric protective layer may be two or more layers. For example, a magnesium oxide layer may be formed on the dielectric layer by an electron beam vapor deposition method, and a layer made of the halogen-containing magnesium oxide fine powder of the present invention may be formed on the magnesium oxide layer.

The fluorescent substance layer containing the halogen-containing magnesium oxide fine powder of this invention can be formed by apply | coating and drying the dispersion liquid which disperse | distributed the halogen-containing magnesium oxide fine powder and phosphor powder on the back plate of AC type PDP. .

The secondary electron emission layer made of the halogen-containing magnesium oxide fine powder of the present invention can be formed by applying and drying a dispersion obtained by dispersing the halogen-containing magnesium oxide fine powder and the phosphor powder in a dispersion medium on a phosphor layer of an AC PDP. Can be.

Example

Example 1

Metal magnesium was injected into the metal magnesium melt evaporator 10 of the magnesium oxide fine powder production apparatus of FIG. 1 from the metal magnesium inlet 12. Next, the metal magnesium was heated and melted while argon was introduced into the dilution gas introduction port 13. Molten magnesium was further heated at a temperature of 1170 ° C. and magnesium vapor was produced at a production rate of 1.01 kg / hour. After the magnesium vapor was generated, 1,1,1,2-tetrafluoroethane (HFC-134a) was 0.64 NL / hour (magnesium vapor) with argon at a flow rate of 3000 NL / hour in the diluent gas inlet 13 2.0 g / hour) as the amount of fluorine relative to 1 kg / hour, and introduced into the magnesium oxidation apparatus 14 as a mixed gas of magnesium vapor, argon and 1,1,1,2-tetrafluoroethane. . Subsequently, air was introduced from the oxygen-containing gas injection port 15 at a flow rate of 25 Nm ³ / hour, the oxygen-containing gas was brought into contact with magnesium vapor, and the magnesium was oxidized to prepare a fluorine-containing magnesium oxide fine powder. The particle shape of the obtained fluorine-containing magnesium oxide fine powder was observed using the electron microscope, and it was confirmed that the primary particle was a cube.

The fluorine content (by the lanthanum alizarin complexx absorbance method) of the obtained fluorine-containing magnesium oxide fine powder was 0.15 mass%, and the BET specific surface area (by the nitrogen adsorption method) was 35.8 m 2 / g (average obtained from the BET specific surface area). The particle diameter was 47 nm). Moreover, when the emission spectrum of the ultraviolet light by the electron beam excitation of the obtained fluorine-containing magnesium oxide fine powder was measured with the cathode luminescence measurement apparatus, the emission spectrum as shown in FIG. 2 was obtained, and the wavelength 240 was obtained by electron beam excitation. It was confirmed to emit ultraviolet light having a peak in the vicinity of nm. The maximum value of the luminescence intensity of the ultraviolet light was 13300 arb.unit.

[Example 2]

In the same manner as in Example 1 except that the flow rate of 1,1,1,2-tetrafluoroethane gas was 3.84 NL / hour (13.6 g / hour as the amount of fluorine relative to 1 kg / hour of magnesium vapor). A fluorine-containing magnesium oxide fine powder was prepared. The particle shape of the obtained fluorine-containing magnesium oxide fine powder was observed using the electron microscope, and it was confirmed that the primary particle was a cube.

The fluorine content of the obtained fluorine-containing magnesium oxide fine powder was 0.30 mass%, and the BET specific surface area was 34.9 m <2> / g (average particle diameter calculated | required from BET specific surface area is 48 nm). Moreover, when the emission spectrum of the ultraviolet light by electron beam excitation of the obtained fluorine-containing magnesium oxide fine powder was measured like Example 1, the emission spectrum similar to FIG. 2 was obtained, and the electron beam excitation was carried out in the vicinity of wavelength 240nm. It was confirmed to emit ultraviolet light having a peak. The maximum value of the luminescence intensity of the ultraviolet light was 25710 arb.unit.

Example 3

Sulfur hexafluoride gas was introduced into the evaporation crucible at a flow rate of 1.68 NL / hour (8.5 g / hour as fluorine amount to 1 kg / hour of magnesium vapor) instead of 1,1,1,2-tetrafluoroethane gas. A fluorine-containing magnesium oxide fine powder was prepared in the same manner as in Example 1 except for the above. The particle shape of the obtained fluorine-containing magnesium oxide fine powder was observed using the electron microscope, and it was confirmed that the primary particle was a cube.

The fluorine content of the obtained fluorine-containing magnesium oxide fine powder was 0.22 mass%, and the BET specific surface area was 37.8 m <2> / g (average particle diameter calculated | required from BET specific surface area is 44 nm). Moreover, when the emission spectrum of the ultraviolet light by electron beam excitation of the obtained fluorine-containing magnesium oxide fine powder was measured like Example 1, the emission spectrum similar to FIG. 2 was obtained, and the electron beam excitation was carried out in the vicinity of wavelength 240nm. It was confirmed to emit ultraviolet light having a peak. The maximum value of the luminescence intensity of the ultraviolet light was 4920 arb · unit.

Example 4

A fluorine-containing magnesium oxide fine powder was produced in the same manner as in Example 3 except that the flow rate of the sulfur fluoride gas was 5.55 NL / hour (28.8 g / hour as the amount of fluorine relative to 1 kg / hour of magnesium vapor). The particle shape of the obtained fluorine-containing magnesium oxide fine powder was observed using the electron microscope, and it was confirmed that the primary particle was a cube.

The fluorine content of the obtained fluorine-containing magnesium oxide fine powder was 0.60 mass%, and the BET specific surface area was 35.4 m <2> / g (average particle diameter calculated | required from BET specific surface area is 47 nm). Moreover, when the emission spectrum of the ultraviolet light by electron beam excitation of the obtained fluorine-containing magnesium oxide fine powder was measured like Example 1, the emission spectrum similar to FIG. 2 was obtained, and the electron beam excitation was carried out in the vicinity of wavelength 240nm. It was confirmed to emit ultraviolet light having a peak. The maximum value of the luminescence intensity of the ultraviolet light was 12920 arb.unit.

Example 5

The heating temperature of the molten magnesium is 1130 ° C. (0.28 kg / hour as the production rate of magnesium vapor), and the flow rate of 1,1,1,2-tetrafluoroethane gas is 0.64 NL / hour (1 kg / magnesium vapor). A fluorine-containing magnesium oxide fine powder was produced in the same manner as in Example 1 except that the amount of fluorine was 7.6 g / hour). The particle shape of the obtained fluorine-containing magnesium oxide fine powder was observed using the electron microscope, and it was confirmed that the primary particle was a cube.

The fluorine content of the obtained fluorine-containing magnesium oxide fine powder was 0.25 mass%, and the BET specific surface area was 86.4 m <2> / g (average particle diameter 19 nm calculated | required from BET specific surface area). Moreover, when the emission spectrum of the ultraviolet light by the electron beam excitation of the obtained fluorine-containing magnesium oxide fine powder was measured like Example 1, the emission spectrum similar to FIG. 2 was obtained and peaked in the vicinity of wavelength 240nm by electron beam excitation. It was confirmed to emit ultraviolet light having The maximum value of the luminescence intensity of this ultraviolet light was 6100 arb.unit.

Comparative Example 1

A magnesium oxide fine powder was produced in the same manner as in Example 1 except that 1,1,1,2-tetrafluoroethane gas was not introduced into the dilution gas inlet. The particle shape of the obtained magnesium oxide fine powder was observed using the electron microscope, and it was confirmed that a primary particle is a cube.

The BET specific surface area of the obtained magnesium oxide fine powder was 35.3 m <2> / g (average particle diameter calculated | required from BET specific surface area is 47 nm). Moreover, when the emission spectrum of the ultraviolet light by the electron beam excitation of the obtained magnesium oxide fine powder was measured like Example 1, the emission of the ultraviolet light which has a peak in the range of 200-300 nm of wavelength was not seen.

Example 6

A fluorine-containing magnesium oxide fine powder was produced in the same manner as in Example 5 except that the flow rate of argon gas was 6000 NL / hour. The particle shape of the obtained fluorine-containing magnesium oxide powder was observed using the electron microscope, and it was confirmed that the primary particle was a cube.

The fluorine content of the obtained fluorine-containing magnesium oxide fine powder was 0.23 mass%, and the BET specific surface area was 155.2 m <2> / g (average particle diameter calculated | required from BET specific surface area is 11 nm). Moreover, when the emission spectrum of the ultraviolet light by the electron beam excitation of the obtained fluorine-containing magnesium oxide fine powder was measured like Example 1, the emission spectrum similar to FIG. 2 was obtained, and the electron beam excitation was carried out in the vicinity of wavelength 240nm. It was confirmed to emit ultraviolet light having a peak. The maximum value of the luminescence intensity of the ultraviolet light was 5250 arb.unit.

Example 7

Fluorine was carried out in the same manner as in Example 6 except that the flow rate of 1,1,1,2-tetrafluoroethane gas was set to 0.06 NL / hour (0.73 g / hour as the amount of fluorine relative to 1 kg / hour of magnesium vapor). A containing magnesium oxide fine powder was prepared. The particle shape of the obtained fluorine-containing magnesium oxide fine powder was observed using the electron microscope, and it was confirmed that the primary particle was a cube.

The fluorine content of the obtained fluorine-containing magnesium oxide fine powder was 0.015 mass%, and the BET specific surface area was 144.8 m <2> / g (average particle diameter calculated | required from BET specific surface area is 12 nm). Moreover, when the emission spectrum of the ultraviolet light by electron beam excitation of the obtained fluorine-containing magnesium oxide fine powder was measured like Example 1, the emission spectrum similar to FIG. 2 was obtained, and the electron beam excitation was carried out in the vicinity of wavelength 240nm. It was confirmed to emit ultraviolet light having a peak. The maximum emission intensity of ultraviolet light was 890 arb.unit.

Example 8

Fluorine in the same manner as in Example 6 except that the flow rate of 1,1,1,2-tetrafluoroethane gas was set to 0.02 NL / hour (0.24 g / hour as the amount of fluorine relative to 1 kg / hour of magnesium vapor). A containing magnesium oxide fine powder was prepared. As a result of observing the particle shape of the obtained fluorine-containing magnesium oxide fine powder using an electron microscope, it was confirmed that the primary particles were a cube.

The fluorine content of the obtained fluorine-containing magnesium oxide fine powder was 0.005 mass%, and the BET specific surface area was 146.0 m <2> / g (average particle diameter calculated | required from BET specific surface area is 11 nm). Moreover, when the emission spectrum of the ultraviolet light by electron beam excitation of the obtained fluorine-containing magnesium oxide fine powder was measured like Example 1, the emission spectrum similar to FIG. 2 was obtained, and the electron beam excitation was carried out in the vicinity of wavelength 240nm. It was confirmed to emit ultraviolet light having a peak. The maximum emission intensity of the ultraviolet light was 220 arb.unit.

Example 9

Fluorine was carried out in the same manner as in Example 5 except that the flow rate of 1,1,1,2-tetrafluoroethane gas was set to 0.01 NL / hour (0.12 g / hour as the amount of fluorine relative to 1 kg / hour of magnesium vapor). A containing magnesium oxide fine powder was prepared. The particle shape of the obtained fluorine-containing magnesium oxide fine powder was observed using the electron microscope, and it was confirmed that the primary particle was a cube.

The fluorine content of the obtained fluorine-containing magnesium oxide fine powder was 0.002 mass%, and the BET specific surface area was 81.6 m <2> / g (average particle diameter calculated | required from BET specific surface area is 21 nm). Moreover, when the emission spectrum of the ultraviolet light by electron beam excitation of the obtained fluorine-containing magnesium oxide fine powder was measured like Example 1, the emission spectrum similar to FIG. 2 was obtained, and the electron beam excitation was carried out in the vicinity of wavelength 240nm. It was confirmed to emit ultraviolet light having a peak. The maximum emission intensity of the ultraviolet light was 210 arb.unit.

Example 10

Fluorine in the same manner as in Example 5 except that the flow rate of 1,1,1,2-tetrafluoroethane gas was set to 0.06 NL / hour (0.73 g / hour as the amount of fluorine relative to 1 kg / hour of magnesium vapor). A containing magnesium oxide fine powder was prepared. The particle shape of the obtained fluorine-containing magnesium oxide fine powder was observed using the electron microscope, and it was confirmed that the primary particle was a cube.

The fluorine content of the obtained fluorine-containing magnesium oxide fine powder was 0.02 mass%, and the BET specific surface area was 78.2 m <2> / g (average particle diameter calculated | required from BET specific surface area is 21 nm). Moreover, when the emission spectrum of the ultraviolet light by the electron beam excitation of the obtained fluorine-containing magnesium oxide fine powder was measured like Example 1, the ultraviolet light which has a peak in the vicinity of wavelength 240nm by electron beam excitation similarly to FIG. It was confirmed to emit light. The maximum value of the luminescence intensity of the ultraviolet light was 1610 arb.unit.

Example 11

Example 1 except that carbon tetrachloride gas was introduced instead of 1,1,1,2-tetrafluoroethane gas at a flow rate of 0.64 NL / hour (4.01 g / hour as chlorine amount to 1 kg / hour of magnesium vapor). In the same manner, a chlorine-containing magnesium oxide fine powder was prepared. The particle shape of the obtained chlorine-containing magnesium oxide fine powder was observed using an electron microscope, and it was confirmed that the primary particles were a cube.

The chlorine content of the obtained chlorine-containing magnesium oxide fine powder was 0.05 mass%, and the BET specific surface area was 36.1 m <2> / g (average particle diameter calculated | required from BET specific surface area is 46 nm). Moreover, as a result of measuring the emission spectrum of ultraviolet light by electron beam excitation of the obtained chlorine-containing magnesium oxide fine powder in the same manner as in Example 1, ultraviolet light having a peak in the vicinity of the wavelength of 240 nm by electron beam excitation similarly to FIG. It was confirmed to emit light. The maximum emission intensity of ultraviolet light was 3840 arb.unit. In addition, chlorine content was measured by ion chromatography.

Example 12

The heating temperature of the molten magnesium was 1130 ° C., the magnesium vapor supply amount was 0.28 kg / hour, and the flow rate of carbon tetrachloride gas was 0.02 NL / hour (0.45 g / hour as the amount of chlorine relative to 1 kg / hour of magnesium vapor), In the same manner as in Example 11, a chlorine-containing magnesium oxide fine powder was prepared. The particle shape of the obtained chlorine-containing magnesium oxide fine powder was observed using an electron microscope, and it was confirmed that the primary particles were a cube.

The chlorine content of the obtained chlorine-containing magnesium oxide fine powder was 0.001 mass%, and the BET specific surface area was 88.0 m <2> / g (average particle diameter calculated | required from BET specific surface area is 19 nm). Moreover, when the emission spectrum of the ultraviolet light by the electron beam excitation of the obtained chlorine-containing magnesium oxide fine powder was measured like Example 1, the emission spectrum similar to FIG. 2 was obtained, and the electron beam excitation was performed in the vicinity of wavelength 240nm. It was confirmed to emit ultraviolet light having a peak. The maximum value of the luminescence intensity of the ultraviolet light was 110 arb.unit.

Example 13

Instead of 1,1,1,2-tetrafluoroethane gas, dichlorofluoromethane gas

Fluorine and chlorine-containing magnesium oxide fine in the same manner as in Example 5, except that a flow rate of 0.64 NL / hour (1.94 g / hour as the amount of fluorine relative to 1 kg / hour of magnesium vapor and 3.62 g / hour as the amount of chlorine) was introduced. Powder was prepared. The particle shape of the obtained fluorine-chlorine-containing magnesium oxide fine powder was observed using an electron microscope, and it was confirmed that the primary particle was a cube.

The fluorine content of the obtained fluorine-chlorine-containing magnesium oxide fine powder was 0.08 mass%, the chlorine content was 0.02 mass%, and the BET specific surface area was 77.3 m 2 / g (average particle size determined from the BET specific surface area was 22 nm). Moreover, when the emission spectrum of the ultraviolet light by electron beam excitation of the obtained fluorine-chlorine containing magnesium oxide fine powder was measured like Example 1, the emission spectrum similar to FIG. 2 was obtained, and the electron beam excitation of wavelength 240nm was carried out. It was confirmed to emit ultraviolet light having a peak in the vicinity. The maximum value of the luminescence intensity of the ultraviolet light was 1770 arb.unit.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structure of an example of the magnesium oxide fine powder manufacturing apparatus which can be advantageously used for the manufacturing method of the halogen-containing magnesium oxide fine powder of this invention.

2 is an emission spectrum of ultraviolet light by electron beam excitation of the fluorine-containing magnesium oxide fine powder prepared in Example 1. FIG.

Explanation of the sign

1 molten magnesium

2 Halogen-containing Magnesium Oxide Fine Powder

10 Metal Magnesium Melt Evaporator

11 Magnesium Steam Jet

12 metal magnesium inlet

13 Diluent Gas Inlet

14 Magnesium Oxidation Device

15 oxygen-containing gas nozzle

16 magnesium oxide fine powder outlet

Claims (9)

A method for producing a halogen-containing magnesium oxide fine powder, wherein magnesium vapor and oxygen-containing gas are brought into contact with each other in a gas atmosphere in which halogen is present in an amount ranging from 0.01 to 500 g per 1 kg of magnesium vapor. The method of claim 1, A method for producing a halogen-containing magnesium oxide fine powder, wherein the halogen is at least one halogen selected from the group consisting of fluorine and chlorine. A halogen-containing magnesium oxide fine powder containing halogen in the range of 0.001 to 10 mass% and having a BET specific surface area in the range of 34 to 350 m 2 / g. The method of claim 3, wherein Halogen-containing magnesium oxide fine powder, wherein the halogen is at least one halogen selected from the group consisting of fluorine and chlorine. The method of claim 3, wherein Halogen-containing magnesium oxide fine powder in which the particle shape of the primary particles is a cube. The method of claim 3, wherein A halogen-containing magnesium oxide fine powder which is excited by an electron beam and emits ultraviolet light having a peak wavelength in a range of 200 to 300 nm. A dielectric protective layer of an alternating current plasma display panel comprising the halogen-containing magnesium oxide fine powder according to claim 3. The phosphor layer of the alternating current plasma display panel containing the halogen-containing magnesium oxide fine powder of Claim 3. The secondary electron emission layer laminated | stacked on the surface of the side which contact | connects the discharge space of the phosphor layer of an alternating current plasma display panel which consists of a halogen-containing magnesium oxide fine powder of Claim 3.

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