JP2007165782A - Magnetic substance manufacturing method and its manufacturing equipment, and magnetic substance particle, and its precursor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic substance manufacturing method which can manufactures magnetic substance particles containing a plurality of metal compositions composing the magnetic substance in a fine structure at a nanometer level in a simple structure. <P>SOLUTION: The magnetic substance manufacturing method includes processes; of flowing a material gas flow ET containing metals composing the magnetic substance and a reactive gas flow GR covering the material gas flow ET into a reactive space HK in a high temperature atmosphere; of forming particles through thermal reaction in a surrounding portion of the material gas flow ET; and of cooling the particles with the reactive gas flow GR to form the magnetic substance particle or a precursor of the magnetic substance particle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a manufacturing method of a magnetic body, a manufacturing apparatus used for the manufacturing method of the magnetic body, and a magnetic body manufactured by the manufacturing method of the magnetic body.

  The magnetic material is used as a material for magnets, transformer cores, optical communication / optical devices and recording devices, but for the production of magnetic materials, conventionally, solid phase methods, liquid phase methods, sputtering methods, Various methods such as vapor deposition, ion plating, and liquid phase epitaxial growth are used.

Among the above methods, in the solid phase method, the magnetic material powder is sufficiently mixed by a ball mill or the like, and then heated and baked (solid phase reaction) under high temperature conditions and then finely pulverized using a ball mill or mortar Thus, magnetic particles are generated.
In the liquid phase method, an aqueous solution of a metal element constituting a magnetic material is neutralized with an aqueous solution of an alkali hydroxide to form a hydroxide precipitate, and the resulting precipitate slurry is hydrothermally treated to produce magnetic particles. (See Patent Document 1).

  In the sputtering method, a magnetic material is fixed on a cathode electrode inside a vacuum chamber, and a substrate for producing a magnetic film is evacuated while being heated to a predetermined temperature, and then a sputtering gas (a mixed gas of argon and oxygen). Is discharged at a predetermined input power density to produce a film (see Patent Documents 2 and 3).

  The vapor deposition method is a method in which a magnetic material is vaporized by a heater in a vacuum chamber and deposited on a substrate on which a magnetic film is to be formed to form a film. The ion plating method is magnetic in a vacuum chamber. The material of the body is evaporated and the evaporation flow is ionized, and the substrate for producing the magnetic film is deposited on the substrate as a cathode electrode to form a film.

  In the liquid phase epitaxial growth method, a supersaturated melt of a magnetic material is brought into contact with a single crystal substrate to grow a single crystal having the same crystal orientation as that of the substrate (Patent Document). 4).

JP 2000-1397 A JP-A-6-263596 JP-A-6-290497 JP 2002-296555 A

  Among the conventional methods for producing magnetic materials, it is difficult to produce magnetic particles with a fine structure of nanometer level by solid phase method using solid phase reaction, but sputtering method, vapor deposition method, ion plating It is possible to produce a magnetic film having a fine structure by the method, the liquid phase epitaxial growth method, or the like. However, it is difficult to increase the film thickness or obtain a large area magnetic material.

  In addition, it is possible to form a magnetic material with a large thickness using magnetic particles produced by a solid phase method, but if the particle size is large, the heat treatment temperature becomes high, and there is a variation in composition at the time of molding. growing. In particular, there is a disadvantage that the variation is larger for a small amount substitution type composition, and the magnetic properties cannot be sufficiently exhibited.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to produce magnetic particles containing a plurality of metal components constituting a magnetic material with a nanometer-level fine structure with a simple configuration. An object of the present invention is to provide a method for producing a magnetic substance, a magnetic substance production apparatus suitable for the production method, magnetic particles produced by the magnetic substance production method, and a precursor thereof.

  In order to achieve the above object, the first characteristic configuration of the method for producing a magnetic body according to the present invention is that a raw material gas stream containing a metal constituting the magnetic body and a reaction gas stream covering the raw material gas stream are in a high-temperature atmosphere. In order to generate magnetic particles or precursors of magnetic particles by forming fine particles by thermal reaction at the outer periphery of the raw material gas flow and cooling the fine particles with the reactive gas flow. is there.

That is, when the raw material gas flow containing the metal constituting the magnetic material and the reaction gas flow covering the raw material gas flow are introduced into the reaction space of the high temperature atmosphere, the outer periphery of the raw material gas flow covered with the reaction gas flow The raw material gas flow undergoes a thermal reaction to produce fine particle nuclei consisting of each metal component of the magnetic material, but the generated core particles are rapidly cooled by the reaction gas flow when moving with the reaction gas flow, Particle coalescence / aggregation and condensation / reaction of vapor onto the particle surface are sufficiently suppressed, resulting in a small particle size magnetic particle or magnetic particle precursor consisting of each metal component of the magnetic material. It is done.
Furthermore, it is a simple configuration in which the raw material gas flow containing each metal component of the magnetic body is flowed into the reaction space of the high temperature atmosphere in a state covered with the reaction gas flow, without undergoing many steps (processes), It is possible to easily generate a magnetic particle having a small particle size or a magnetic particle precursor composed of each metal component of the magnetic material.
Accordingly, there is provided a method for producing a magnetic body that can produce magnetic particles containing a plurality of metal components constituting the magnetic body with a nanometer-level fine structure with a simple structure.

The second characteristic configuration is that a magnetic particle is generated by heat-treating the precursor of the magnetic particle.
That is, when the fine particles generated in the method for producing a magnetic material having the first characteristic configuration are precursors of magnetic particles, the magnetic particles can be obtained by heat-treating the precursor of the magnetic particles.
Accordingly, there is provided a method for producing a magnetic material, in which magnetic particles are produced from a precursor of magnetic particles containing a plurality of metal component particles constituting the magnetic material with a fine structure of nanometer level.

  The third characteristic configuration is that the raw material gas flow and the reaction gas flow cause a chemical reaction to generate heat.

That is, the heat generated by the chemical reaction between the raw material gas flow and the reactive gas flow causes the raw material gas flow to undergo a thermal reaction to generate fine particle nuclei composed of each metal component of the magnetic material. Magnetic particles or precursors thereof are produced while cooling with a flow to suppress coalescence / aggregation and condensation / reaction of vapor onto the particle surface.
Therefore, a chemical reaction between a raw material gas stream and a reactive gas stream, for example, a raw material gas stream utilizing heat generated by combustion of a raw material gas stream containing hydrocarbons by a reactive gas stream containing oxygen gas (oxidation reaction). The thermal reaction can be performed efficiently.

  The fourth characteristic configuration is that the reaction gas flow is composed of an oxygen-containing gas and the magnetic material is formed as a metal oxide.

That is, the metal component of the magnetic substance in the raw material gas stream reacts with the oxygen-containing gas constituting the reaction gas stream, and magnetic substance particles in which the magnetic substance is formed as a metal oxide or a precursor thereof are generated.
Therefore, the magnetic substance is formed as a metal oxide, and magnetic particles having excellent stability or a precursor thereof can be obtained.

  The characteristic configuration of the magnetic body manufacturing apparatus according to the present invention is used in the method according to any one of the first to fourth characteristic configurations described above, and is a liquid that ejects a raw material liquid containing a metal that constitutes the magnetic body. There exists a nozzle and the gas nozzle which is located in the circumference | surroundings of the said liquid nozzle, and ejects the gas which forms a reaction gas flow along the axial center direction of the said liquid nozzle.

That is, when the raw material liquid containing the metal constituting the magnetic material is ejected from the liquid nozzle and the gas forming the reaction gas flow is ejected from the gas nozzle located around the liquid nozzle along the axial direction of the liquid nozzle. The raw material liquid ejected from the liquid nozzle is atomized by the gas ejected from the gas nozzle into a droplet flow, and this droplet flow evaporates in the reaction space of a high temperature atmosphere as the temperature rises and the vapor pressure rises. It vaporizes and changes into a raw material gas flow, and a raw material gas flow and a reaction gas flow covering the raw material gas flow are formed.
Here, the liquid ejection is stable, and it is easy to set the ratio of the supply amount of each metal in the raw material liquid. It becomes possible to obtain magnetic particles composed of metal components or precursors thereof.
Therefore, while appropriately setting the supply amount of each metal using a raw material liquid containing a plurality of metals as raw materials for magnetic particles, it is possible to appropriately form a raw material gas flow covered with a reactive gas flow, Provided is a production apparatus suitable for producing magnetic particles composed of metal components having a complicated composition ratio or precursors thereof.

The first characteristic configuration of the magnetic particles or precursor thereof according to the present invention is manufactured by the method of any one of the first to fourth characteristic configurations, the average particle diameter is in the range of 10 nm to 5000 nm, and The specific surface area is in the range of 0.1 to 100 m ² / g.

That is, magnetic particles having a small particle diameter and a large specific surface area are more uniform when dispersed in a medium such as a resin. Moreover, when sintering, it can sinter at lower temperature.
Therefore, by limiting the average particle diameter and specific surface area to the above ranges, a highly useful magnetic material is provided.

Embodiments of a magnetic body manufacturing method and manufacturing apparatus according to the present invention, and magnetic particles manufactured by the method and precursors thereof will be described below with reference to the drawings.
FIG. 1 shows the configuration of the main part of a particle production system used for production of magnetic particles of the present invention. The particle production system includes a reactor 10 as a fine particle production apparatus, a recovery device 20 that cools and collects fine particles generated in the reactor 10, and the like. Although not shown, the fine particles emitted from the reactor 10 pass through the cooling tower and are cooled, and then collected by a collection device such as a bag filter, a cyclone, an electrostatic precipitator, or a scrubber provided in the collection unit 20.

  The pressure in the reactor 10 is reduced or increased by an exhaust device provided on the downstream side of the recovery device 20. Here, although not shown, as an exhaust device, specifically, an exhaust fan and a damper are provided in the exhaust passage, and the internal pressure of the reactor 10 is maintained at a constant pressure (for example, reduced to about −10 kPa). In addition, based on the measurement information of the pressure sensor that measures the internal pressure of the reactor 10, the number of rotations of the fan motor that drives the exhaust fan is inverter-controlled, or the opening degree of the damper is changed and adjusted. By maintaining the internal pressure of the reactor 10 at a constant pressure in this way, the flow rate of the reaction gas flow GR described later is stabilized, and the size (particle size) of the produced magnetic particles and precursor particles thereof is stabilized. Is obtained. Further, in order to maintain the internal pressure of the reactor 10 at a constant pressure, a pressure sensor is installed in equipment such as the piping after the reactor 10 and a cooling tower / collector, and based on the measurement information of the pressure sensor, You may make it perform the rotation speed control of a fan motor, and the opening degree adjustment of a damper.

  The reactor 10 includes a cylindrical container 1 having a tapered particle outlet or a container having a short tube attached to a non-tapered cylinder. A high temperature atmosphere is provided inside the container 1 above the container 1. A plasma generator 2 is installed as a heat source for creating the reaction space HK. The plasma generator 2 is supplied with a discharge argon gas by a supply tube 7. Incidentally, the supply amount of argon gas in the plasma generator 2 is about 50 liters / min, and the plasma output is about 7 kW. The gas supplied to the plasma generator 2 is not limited to argon gas alone, but may be a mixed gas in which helium gas, hydrogen gas or nitrogen gas is added to argon gas, for example, about 20%. That is, since the thermal conductivity differs depending on the type of gas, the plasma temperature can be controlled by changing the composition of the gas supplied to the plasma generator 2. Although not described in detail, a gas burner or the like can be used as the heat source in addition to the plasma generator.

A single nozzle unit 3 is installed on the inlet 1 side wall of the container 1 with the injection direction directed into the container 1. As shown in FIGS. 2 and 3, the nozzle unit 3 is located around the liquid nozzle 4 for ejecting a raw material liquid containing a metal constituting the magnetic body, and forms a reaction gas flow GR. And a gas nozzle 5 that ejects the gas (specifically, oxygen gas) along the axial direction of the liquid nozzle 4. Here, as the raw material liquid containing the metal constituting the magnetic material, a metal-containing organic solvent solution such as a metal alkoxide, a metal complex, or an organometallic compound of the metal component is used as described later. The gas nozzle 5 is supplied with oxygen gas from the supply pipe 5a, and the liquid nozzle 4 is supplied with raw material liquid from the supply pipe 4a (see FIG. 1). Incidentally, the supply amount of oxygen gas from the gas nozzle 5 is about 0.3 m ³ / min, and the supply capacity of the raw material liquid from the liquid nozzle 4 is about 100 g / min.

  In addition, arrangement | positioning of the said plasma generator 2 and the nozzle unit 3 with respect to the container 1 is not restricted to the arrangement | positioning shown in FIG. 1, It can set arbitrarily. For example, in FIG. 1, the plasma generator 2 and the nozzle unit 3 may be interchanged, the plasma generator 2 may be installed on the inlet side lateral wall of the container 1, and the nozzle unit 3 may be installed on the top of the container 1.

  The gas nozzle 5 is formed concentrically with the liquid nozzle 4 in the axial direction of the liquid nozzle 4. Specifically, the liquid nozzle 4 is formed in a circular shape, and the gas nozzle 5 is formed in an annular shape around the circular liquid nozzle 4. FIG. 2 schematically shows the structure of each of the nozzles 4 and 5. FIG. 2A shows a gas / liquid external mixing type, and FIG. 2B shows a gas / liquid internal mixing type.

  The structure of the nozzle unit 3 is not limited to a structure (FIG. 2) in which flow paths for the liquid nozzle 4 and the gas nozzle 5 are formed in a single member such as a cylindrical shape. For example, a single liquid nozzle is the center. And a nozzle unit in which a plurality of gas nozzles separate from the liquid nozzles are arranged symmetrically around the liquid nozzle.

  Further, although not shown, the fine particle production apparatus of the present invention includes a cooling means for cooling the reaction space HK according to the size of the magnetic particles to be produced and the precursor particles thereof. Specifically, a water cooling jacket is disposed on the outer periphery of the container 1 to cool it from the outside of the container, and a cooling gas (oxygen gas or the like) or liquid (water or the like) is blown into the container 1. Direct cooling means or the like can be used.

  Next, as schematically shown in FIG. 3, a method for producing a magnetic powder according to the present invention includes a raw material gas flow ET containing a metal constituting the magnetic material and a reaction gas flow covering the raw material gas flow ET. GR is allowed to flow into the reaction space HK in a high-temperature atmosphere, and fine particles are formed by a thermal reaction at the outer periphery of the raw material gas flow ET, and the fine particles are cooled by the reaction gas flow GR to be magnetic particles or magnetic particle precursors. The body is generated. The source gas flow ET causes the thermal reaction due to heat generated by a chemical reaction between the source gas flow ET and the reaction gas flow GR. Specifically, the raw material gas stream ET contains hydrocarbons, the reaction gas stream GR is composed of an oxygen-containing gas, and the hydrocarbons in the raw material gas stream ET are burned with the oxygen-containing gas to generate heat, and the raw material A metal component in the gas stream ET is oxidized to generate a metal oxide, and a magnetic particle or a precursor of the magnetic particle in which a magnetic material is formed as a metal oxide is generated.

  In the present embodiment, a droplet stream ET containing a magnetic substance raw material (a plurality of types of metals constituting the magnetic substance) is ejected into a reaction space HK in a high-temperature atmosphere in a state where the droplet stream ET is positioned inside the reaction gas stream GR. Then, the raw material gas flow ET is made by vaporization. That is, when the ejected droplet flow ET travels in the reaction space HK, it evaporates and vaporizes as the temperature rises and changes to a raw material gas flow ET. Accordingly, the left base side of the flow portion represented by ET is a droplet flow region, and the right tip side is a raw material gas flow region. In FIG. 3, reference numeral 3 denotes the nozzle unit that forms the droplet flow (raw material gas flow) ET and the reaction gas flow GR. By this nozzle unit 3, the cone spreading angle θg of the reaction gas flow GR is changed to the droplet flow. (Raw material gas flow) It is formed to be larger than the spread angle θe of the cone of ET.

Next, the production mechanism of the magnetic particles or precursor particles of the present invention will be described.
(1) The magnetic particles and the precursor particles are reaction regions (combustion zone) HR generated in the outer peripheral portion of the raw material gas flow ET (specifically, near the interface of the reactive gas flow GR in contact with the raw material gas flow ET). Is generated.
(2) The generated particles in the reaction region HR move at a speed equivalent to the moving speed of the reaction gas flow GR.
(3) When the injection amount of the reaction gas from the nozzle unit 3 is reduced and the moving speed of the reaction gas flow GR is lowered, a high temperature area due to heat propagation from the reaction space HK widens, and the reaction region HR moves toward the nozzle unit 3 side. Approach (state of FIG. 3 (C)). As a result, the residence time in which the generated particles stay in the reaction region HR (the time during which the particles are kept in a high temperature atmosphere) is lengthened, and the progress of the thermal reaction at a high temperature is accelerated. Therefore, the coalescence of the generated particles is promoted and the particle size is increased.
(4) Conversely, when the amount of reaction gas injected from the nozzle unit 3 is increased to increase the moving speed of the reaction gas flow GR, the expansion of the high-temperature area due to heat propagation from the reaction space HK is suppressed, and the reaction region HR Becomes far from the nozzle 3 side (state shown in FIG. 3B). As a result, the residence time in which the generated particles stay in the reaction region HR (the time during which the particles are kept in the high temperature atmosphere) is shortened, so that the thermal reaction at high temperature does not proceed so much, and the cooling action is caused by the increase in the velocity of the reaction gas flow GR. Therefore, the coalescence of particles is suppressed and the particle size is reduced.

Accordingly, by changing the ratio of the flow rate of the reaction gas flow GR to the flow rate of the raw material gas flow (actually a droplet flow) ET (hereinafter referred to as a gas-liquid ratio), the size of the magnetic particles or their precursor particles is changed. Can be adjusted.
That is, when the gas-liquid ratio is large, the flow rate of the reaction gas flow GR increases and the thickness of the gas layer increases, and the amount of ambient gas that absorbs the heat of the generated particles increases. As a result, the cooling effect on the generated particles is increased, the reaction region HR is shortened, and the residence time of the generated particles in the reaction region HR is shortened. The diameter becomes smaller.
On the other hand, when the gas-liquid ratio is small, the flow rate of the reaction gas flow GR decreases and the thickness of the gas layer decreases, and the amount of surrounding gas that absorbs the heat of the generated particles decreases. As a result, the cooling effect on the generated particles is reduced, the reaction region HR becomes longer, and the residence time of the generated particles in the reaction region HR becomes longer. The particle diameter increases.

  Furthermore, in the method for producing a magnetic material according to the present invention, when the magnetic particle precursor particles are generated by the fine particle manufacturing apparatus, the magnetic particle precursors are heated to generate the magnetic particles. To do. Specifically, the magnetic particle precursor recovered by the recovery device 20 is heat-treated at a temperature of 500 to 1200 ° C. in a reducing or atmospheric atmosphere using a heating furnace (not shown), and the processed product. Is pulverized (pulverized) with a wet or dry ball mill to obtain a product. In addition, you may add an appropriate additive as needed at the time of heat processing.

Next, the magnetic powder (particle) products according to the present invention will be listed and described below.
First, γ-Fe ₂ O ₃ , Fe ₃ O ₄ , M _1-x Zn _x Fe ₂ O ₄ (where 0 ≦ x <1, and M is selected from Mg, Mn, Co, Ni, Cu). , Fe ₂ O ₃ —Bi ₂ O ₃ —A (where A is selected from CaO, Li ₂ O, and CuO), Sr ₈ CaRe ₃ Cu ₄ O _24, and other metal oxides are magnetic recording materials, magnets, Examples of products for transformer cores.

Moreover, the general formula _{A x B 3-x M y} Fe 5-y O 12 ( provided that, 0 ≦ x <3,0 ≦ y <5) magneto-optical material and the like represented by.
In the above formula, A is selected from Bi, Ca, Ce, Pb, Pt and the like.
B is at least one element selected from yttrium (Y) or a rare earth element, and is Ce, Dy, Eu, Er, Gd, Ho, La, Lu, Nd, Pm, Pr, Sm, Tb, Tm, Y, Yb, etc.
M is Al, Co, Cr, Cu, Fe (II), Ga, Ge, Hf, In, Li, Mn, Mo, Nd, Ni, Pb, Rh, Ru, Sc, Si, Sn, Ti, V, At least one element selected from Zn, Zr and the like.

Specific examples include Ce _0.7 Y _2.3 CoFe ₄ O ₁₂ , Bi _0.5 Y _2.5 Fe ₅ O ₁₂ , Bi _1.3 Gd _0.7 LuFe ₅ O ₁₂ , Bi _0.5 Dy _{2. 5 Fe 5 O 12, Bi 2} DyGa 0.8 Fe 4.2 O 12, Dy 3 Ga 1.2 Fe 3.8 O 12, Dy 2 TbAlFe 4 O 12, Bi 2.2 Dy 0.8 Al 1. _{2 Fe 3.8 O 12, Bi 2} TbGa 0.8 Fe 4.2, Nd 3 Ga 5 O 12, Ce 1.2 Tb 0.8 YFe 5 O 12, BiGd 2 Ga 2.3 Fe 2.7 O ₁₂ etc. are mentioned.

  The magnetic powder product according to the present invention is not limited to the magnetic powder product having the composition listed above, but includes a combination of other compositions.

Next, the raw material of the magnetic particles according to the present invention will be described.
An organic metal compound (such as a metal complex) of each metal constituting the magnetic material is used as a raw material solution in a state diluted with a solvent. Hereinafter, organometallic compound names are exemplified.
Al: Aluminum mono-n-butoxy diethyl acetoacetate or ethyl acetoacetate aluminum dinormal butyrate, and mixtures thereof Bi: Bismuth 2-ethylhexanoate Ca: Calcium 2-ethylhexanoate Ce: 2-ethyl Cerium hexanoate Co: Cobalt 2-ethylhexanoate Cr: Chromium 2-ethylhexanoate Cu: Copper 2-ethylhexanoate or copper naphthenate Dy: Dysprosium 2-ethylhexanoate Er: Erbium 2-ethylhexanoate Eu : Eurobium 2-ethylhexanoate Fe: Ferric 2-ethylhexanoate Ga: Gallium 2-ethylhexanoate Gd: Gadolinium 2-ethylhexanoate Ge: Germanium 2-ethylhexanoate Ho: 2-ethylhexane Holmium In: Indium 2-ethylhexanoate La: Lanthanum 2-ethylhexanoate Li: Lithium naphthenate Lu: Lutetium 2-ethylhexanoate Mn: Manganese 2-ethylhexanoate Nd: Neodymium 2-ethylhexanoate Ni: 2- Nickel ethylhexanoate Pb: Lead 2-ethylhexanoate Pm: Promethium 2-ethylhexanoate Pr: Praseodymium 2-ethylhexanoate Pt: Bis (acetylacetonato) platinum Ru: Tris (acetylacetonato) ruthenium Si: Octamethyl Cyclotetrasiloxane or polydimethylsiloxane and mixtures thereof Sc: scandium 2-ethylhexanoate Sm: samarium 2-ethylhexanoate Sn: tin 2-ethylhexanoate Tb: 2-ethyl Terbium Sanate Ti: Tetra (2-ethylhexyl) titanate, tetraisopropyl titanate, di-i-propoxytitanium, tetra-n-butoxytitanium Tm: Thulium 2-ethylhexanoate V: Vanadium naphthenate or 2-ethylhexane Vanadium acid and mixtures thereof Y: Yttrium 2-ethylhexanoate Yb: Ytterbium 2-ethylhexanoate Zn: Zinc 2-ethylhexanoate Zr: Zirconium 2-ethylhexanoate

As the diluting solvent, for example, the following can be used.
1) Mineral spirit, 2) Mineral thinner, 3) Petroleum spirit, 4) White spirit, 5) Mineral turpentine, 6) Kerosene, 7) N-hexane, 8) Hexanoic acid, 9) 2-ethylhexane Acid, 10) cyclohexane, 11) isoheptane, 12) ethanol, 13) methanol, 14) 1-propanol, 15) acetic acid, 16) 1-pentanol, 17) valeric acid, 18) toluene, 19) isopropyl alcohol, 20 ) N-propyl alcohol, 21) isobutyl alcohol, 22) n-butyl alcohol, 23) benzene, 24) xylene

[Another embodiment]
In the above embodiment, oxygen gas is used as a gas for forming the reaction gas flow GR, a chemical reaction (oxidation reaction) is caused with the raw material gas flow ET, heat is generated by combustion, and the raw material gas is generated by the generated heat. The flow ET is thermally reacted to generate magnetic particles made of metal oxide or its precursor particles. However, a nitriding reaction is caused by using nitrogen gas instead of oxygen gas, and a magnetic material made of nitride. It is also possible to produce body particles or precursor particles thereof. Moreover, in order to generate the heat | fever for the said raw material gas flow ET to raise | generate a thermal reaction, you may use reactions other than a chemical reaction. Furthermore, the raw material gas flow ET may be thermally reacted only with heat supplied from a heat source such as plasma to generate fine particles.

  In the above embodiment, the raw material liquid containing the metal constituting the magnetic material is ejected from the liquid nozzle 4 to generate the droplet stream ET, and then the droplet stream ET is evaporated to form the source gas stream ET. However, a raw material gas flow ET may be formed by ejecting a raw material gas prepared in advance in a state containing the metal constituting the magnetic body from a gas nozzle.

Next, as examples, two materials, Y ₃ Fe ₅ O ₁₂ (Example 1) and Bi _0.5 Y _2.5 Fe ₅ O ₁₂ (Example 2), which are magneto-optical materials, are taken as examples. explain.

As a raw material, yttrium 2-ethylhexanoate, ferric 2-ethylhexanoate, and mineral spirit were prepared and mixed so as to have a predetermined molar ratio as a raw material liquid. particles consisting of ₃ Fe ₅ O ₁₂ was prepared.

A TEM photograph of the produced Y ₃ Fe ₅ O ₁₂ particles is shown in FIG. From FIG. 4, it can be read that the particle diameter is distributed in the range of 15 to 75 nm.

FIG. 5 is a graph of X-ray diffraction results of heat treatment for 2 hours before and after heat treatment at 640.degree. C., 840.degree. C., and 1000.degree. C. (Note that the graphs are 640.degree. C., 840.degree. Corresponding to each processing temperature of ° C.). Table 1 shows the BET specific surface area (m ² / g) and the BET equivalent diameter (nm) before and after the heat treatment. The true density of this material was 5.54 g / cm ³ and the BET equivalent diameter was calculated from the following formula (1).

From FIG. 5, in the magnetic particles of this material, the crystalline state is not clear in the state before the heat treatment and the heat treatment temperatures of 640 ° C. and 840 ° C., and the crystal state clearly appears at the heat treatment temperature of 1000 ° C. This is supported by the fact that, as shown in Table 1, the specific surface area (m ² / g) is smaller at the heat treatment temperature of 1000 ° C. than the state before the heat treatment, and the crystallization is promoted by the heat treatment. It is done. Moreover, it turns out that the color of a magnetic body particle also changes with heat processing. Therefore, it can be seen that Y ₃ Fe ₅ O ₁₂ produces a precursor of magnetic particles in a state before heat treatment, and magnetic particles are produced by heat-treating the precursor at a temperature of 1000 ° C. At this time, as shown in Table 1, magnetism is also exhibited.

As raw materials, yttrium 2-ethylhexanoate, bismuth 2-ethylhexanoate, ferric 2-ethylhexanoate, and mineral spirits were prepared and mixed so as to have respective molar ratios, and the raw material liquid was used. Particles made of Bi _0.5 Y _2.5 Fe ₅ O ₁₂ were produced by the particle production system shown.

A TEM photograph of the produced Bi _0.5 Y _2.5 Fe ₅ O ₁₂ particles is shown in FIG. From FIG. 6, it can be seen that the particle size is relatively small and distributed in the range of 20 to 100 nm.

FIG. 7 shows a graph of X-ray diffraction results of heat treatment for 0.5 hour under the respective temperature conditions of 840 ° C., 900 ° C., 950 ° C., and 1000 ° C. Corresponding to each processing temperature of 900 ° C., 950 ° C., and 1000 ° C.). Table 2 shows the BET specific surface area (m ² / g) and the BET equivalent diameter (nm) before and after the heat treatment. In addition, the true density of this material was set to 5.72 g / cm ³ , and the BET equivalent diameter was calculated from the formula (1).

From FIG. 7, in the magnetic particles of this material, the crystal state clearly appears when the heat treatment temperature is 900 ° C. This is supported by the fact that, as shown in Table 2, the specific surface area (m ² / g) decreases at a heat treatment temperature of 900 ° C. It can also be seen that the color of the magnetic particles changes with the change of the crystal state by the heat treatment. Therefore, Bi _0.5 Y _2.5 Fe ₅ O ₁₂ produces a magnetic particle precursor in a state before heat treatment, and the magnetic particle is produced by heat-treating the precursor at a temperature of 900 ° C. or higher. I understand that At this time, as shown in Table 2, magnetism is also exhibited.

The magnetic particles according to the present invention can be applied to optical communication / optical devices and recording devices for various uses as exemplified below, magnets, transformer cores, and the like.
(Specific application examples of magnetic materials) Optical isolators, optical circulators, optical switches, magnetic field sensors, magnetic memories, magnetic disks

Sectional drawing which shows the whole structure of the magnetic particle manufacturing apparatus based on this invention Sectional view and front view schematically showing the structure of the nozzle part The figure which illustrates typically the production | generation process of the magnetic fine particle which concerns on this invention Transmission electron micrograph of magnetic fine particles of Example 1 The figure which shows the X-ray-diffraction pattern of the magnetic body fine particle of Example 1. Transmission electron micrograph of magnetic fine particles of Example 2 The figure which shows the X-ray-diffraction pattern of the magnetic body fine particle of Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 2 Plasma generator 3 Nozzle unit 4 Liquid nozzle 4a Supply pipe 5 Gas nozzle 5a Supply pipe 7 Supply pipe 10 Reactor (microparticle production apparatus)
20 Collector ET Raw material gas flow (droplet flow)
GR reaction gas flow HK reaction space HR reaction region

Claims (6)

  A raw material gas flow containing a metal constituting the magnetic body and a reaction gas flow covering the raw material gas flow are allowed to flow into a reaction space in a high-temperature atmosphere, and fine particles are formed by a thermal reaction at the outer periphery of the raw material gas flow. The method for producing a magnetic material, wherein the fine particles are cooled by the reaction gas flow to generate magnetic particles or a precursor of magnetic particles.   The method for producing a magnetic material according to claim 1, wherein the magnetic particle precursor is generated by heat-treating the magnetic particle precursor.   The method for producing a magnetic body according to claim 1, wherein the raw material gas flow and the reaction gas flow cause a chemical reaction to generate heat.   The method for producing a magnetic body according to any one of claims 1 to 3, wherein the reaction gas flow is constituted by an oxygen-containing gas, and the magnetic body is formed as a metal oxide. It is a manufacturing apparatus of the magnetic body used for the method according to any one of claims 1 to 4,
A liquid nozzle that ejects a raw material liquid containing a metal constituting the magnetic body, and a gas nozzle that is positioned around the liquid nozzle and ejects a gas that forms a reaction gas flow along the axial direction of the liquid nozzle An apparatus for manufacturing a magnetic body. Magnetic particles produced by the method according to any one of claims 1 to 4, having an average particle diameter in the range of 10 nm to 5000 nm, and a specific surface area in the range of 0.1 to 100 m ² / g. Or a precursor of magnetic particles.