WO2023210649A1 - COLUMNAR PARTICLES OF β-SILICON NITRIDE, COMPOSITE PARTICLES, SINTERED SUBSTRATE FOR HEAT RADIATION, RESIN COMPOSITE, INORGANIC COMPOSITE, METHOD FOR PRODUCING COLUMNAR PARTICLES OF β-SILICON NITRIDE, AND METHOD FOR PRODUCING COMPOSITE PARTICLES - Google Patents

COLUMNAR PARTICLES OF β-SILICON NITRIDE, COMPOSITE PARTICLES, SINTERED SUBSTRATE FOR HEAT RADIATION, RESIN COMPOSITE, INORGANIC COMPOSITE, METHOD FOR PRODUCING COLUMNAR PARTICLES OF β-SILICON NITRIDE, AND METHOD FOR PRODUCING COMPOSITE PARTICLES Download PDF

Info

Publication number
WO2023210649A1
WO2023210649A1 PCT/JP2023/016330 JP2023016330W WO2023210649A1 WO 2023210649 A1 WO2023210649 A1 WO 2023210649A1 JP 2023016330 W JP2023016330 W JP 2023016330W WO 2023210649 A1 WO2023210649 A1 WO 2023210649A1
Authority
WO
WIPO (PCT)
Prior art keywords
silicon nitride
particles
composite
columnar particles
columnar
Prior art date
Application number
PCT/JP2023/016330
Other languages
French (fr)
Japanese (ja)
Inventor
和人 原田
好晴 鏡
博明 和泉
Original Assignee
株式会社燃焼合成
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社燃焼合成 filed Critical 株式会社燃焼合成
Publication of WO2023210649A1 publication Critical patent/WO2023210649A1/en

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00—Nitrogen; Compounds thereof
    • C01B21/06—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
    • C01B21/068—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with silicon
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C04B35/584—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon nitride
    • C04B35/587—Fine ceramics
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/34—Silicon-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds

Definitions

  • the present invention relates to ⁇ silicon nitride columnar particles, composite particles, a sintered substrate for heat dissipation, a resin composite, an inorganic composite, a method for producing ⁇ silicon nitride columnar particles, and a method for producing composite particles.
  • insulating inorganic fillers include alumina, boron nitride (BN), and aluminum nitride (AlN).
  • alumina is the cheapest and most used inorganic filler, but heat dissipation materials using alumina have not been able to sufficiently increase thermal conductivity.
  • Patent No. 6245602 Japanese Patent Application Publication No. 2004-352539 Patent No. 6845402
  • silicon nitride particles have very poor filling properties, and there is a problem in that the thermal conductivity of a heat dissipating material containing silicon nitride particles cannot be made sufficiently high.
  • alpha silicon nitride has been sold in large quantities as a sintering material
  • beta silicon nitride has insufficient sintering strength, so its sales volume has been small and its uses have been limited.
  • ⁇ silicon nitride has not been a material that has been fully expected to be used as a heat dissipation filler.
  • the present invention was made in view of the above problems, and includes ⁇ silicon nitride columnar particles, composite particles, a sintered substrate for heat dissipation, a resin composite, and an inorganic composite, which have excellent thermal conductivity and filling properties.
  • Another object of the present invention is to provide a method for producing ⁇ -silicon nitride columnar particles and a method for producing composite particles.
  • the ⁇ silicon nitride columnar particles in the present invention are columnar particles with an average particle diameter D50 of 10 ⁇ m or more and 200 ⁇ m or less, and have an aspect ratio of 0.05 or more and 0.6 or less as determined by SEM image analysis. .
  • the average particle diameter D50 is preferably 25 ⁇ m or more and 100 ⁇ m or less.
  • the composite particles in the present invention include the ⁇ silicon nitride columnar particles described above and the ⁇ silicon nitride pulverized particles, have an average particle diameter D50 of 5 ⁇ m or more and 150 ⁇ m or less, and have an aspect ratio determined by SEM image analysis. It is characterized by being 0.4 or more and 0.7 or less.
  • the sintered substrate for heat dissipation in the present invention is characterized by being formed by firing the ⁇ silicon nitride columnar particles described above or the composite particles described above.
  • the resin composite in the present invention is characterized by containing the ⁇ silicon nitride columnar particles described above or the composite particles described above.
  • the inorganic composite in the present invention is characterized by containing the ⁇ silicon nitride columnar particles described above or the composite particles described above.
  • the method for producing ⁇ -silicon nitride columnar particles in the present invention includes synthesizing ⁇ -silicon nitride composite crystals by a combustion synthesis method in a nitrogen atmosphere using a raw material containing Si; is crushed and classified to obtain columnar particles having an average particle diameter D50 of 10 ⁇ m or more and 200 ⁇ m or less, and an aspect ratio of 0.05 or more and 0.6 or less as determined by SEM image analysis.
  • the method for producing composite particles in the present invention includes crushing the agglomerated powder after extracting the ⁇ silicon nitride columnar particles described above to obtain crushed ⁇ silicon nitride particles, and then grinding the ⁇ silicon nitride columnar particles. and the ⁇ silicon nitride pulverized particles to obtain composite particles having an average particle diameter D50 of 5 ⁇ m or more and 150 ⁇ m or less, and an aspect ratio of 0.4 or more and 0.7 or less as determined by SEM image analysis. It is characterized by
  • the ⁇ silicon nitride columnar particles of the present invention have better water resistance and thermal conductivity than AlN. Furthermore, the filling rate can be increased, and it can be put to practical use in a variety of applications, such as as a heat dissipation filler or as a seed crystal for sintered substrates.
  • FIG. 1A is a scanning electron micrograph of a ⁇ -silicon nitride composite crystal.
  • FIG. 1B is a partial schematic diagram of FIG. 1A.
  • FIG. 2A is a scanning electron micrograph of beta silicon nitride columnar particles.
  • FIG. 2B is a partial schematic diagram of FIG. 2A.
  • FIG. 3B is a partial schematic diagram of FIG. 3A.
  • FIG. 4B is a partial schematic diagram of FIG. 4A.
  • the silicon nitride filler described in Patent Document 1 is agglomerated particles containing columnar silicon nitride particles. Although such a silicon nitride filler has a shape that can be easily obtained by combustion synthesis and has excellent productivity, since it has a shape in which columnar particles are aggregated, irregularities and holes are present on the filler surface. For this reason, the specific surface area becomes very large, and there is a problem with filling properties.
  • the rod-shaped silicon nitride filler described in Patent Document 2 is produced by heat-treating silicon nitride powder in flux and then repeating alkaline solution treatment and acid solution treatment to dissolve the flux component.
  • a method in which a mixture of a frac component and silicon nitride is heat-treated at a high temperature of 1,600 to 1,900 degrees Celsius in a nitrogen or argon atmosphere, and then washed with alkali and acid multiple times to obtain a rod-shaped silicon nitride filler. is proposed.
  • the manufacturing process is complicated and production costs are high.
  • Patent Document 2 is an unrealistic method in which a highly corrosion-resistant silicon nitride sintered body is formed and grain boundaries are melted to obtain columnar crystals. Further, although it is not described in Patent Document 2, the average particle diameter D50 is expected to be considerably small.
  • Patent Document 3 discloses an invention relating to crystal-oriented ceramics having composite particles (C) consisting of magnetically anisotropic particles (A) and seed particles (B), in which the seed particles (B) have ⁇ -nitrided Silicon is chosen.
  • C composite particles
  • the configuration described in Patent Document 3 has high production costs and is difficult to put into practical use. Further, there are also problems in that the average particle diameter D50 is very small and the orientation effect is also low.
  • Non-Patent Document 1 discloses a method of manufacturing silicon nitride nanowires by a reductive nitriding method. In this method, a method has been proposed in which a metal catalyst and carbon are added to SiO 2 and the mixture is maintained at 1850° C. for 10 hours in a nitrogen atmosphere of 0.95 MPa.
  • the crystal thickness is very small, 1 ⁇ m or less, has poor heat transfer efficiency, and contains impurities.
  • Non-Patent Document 2 ⁇ Si 3 N 4 is added as a seed crystal to form a sintered body.
  • a method has been proposed in which sintering is carried out in a nitrogen atmosphere of 0.9 MPa and maintained at 1850° C. for 6 hours.
  • sintering is carried out in a nitrogen atmosphere of 0.9 MPa and maintained at 1850° C. for 6 hours.
  • it is necessary to maintain a high-temperature, high-pressure atmosphere for a long time, and special equipment is required, leading to high costs.
  • columnar particles grow from seed crystals, the size of the columnar particles is very small, and there is also the problem that the orientation effect is low.
  • the ⁇ silicon nitride columnar particles in this embodiment are columnar particles with an average particle diameter D50 of 10 ⁇ m or more and 200 ⁇ m or less, and an aspect ratio determined by SEM image analysis of 0.05 or more and 0.6 or less. shall be.
  • FIG. 1A is a scanning electron microscope (SEM) photograph of a ⁇ -silicon nitride composite crystal.
  • FIG. 1B is a partial schematic diagram of FIG. 1A.
  • the ⁇ silicon nitride composite crystal (polycrystal) produced by the combustion synthesis method is a state in which many columnar particles (column filler) are aggregated, and this is crushed.
  • columnar particles having an average particle diameter D50 of 10 ⁇ m or more and 200 ⁇ m or less can be obtained (see FIGS. 2A and 2B).
  • columnar crystals consisting of many columnar particles with a size of 10 ⁇ m or more and 200 ⁇ m or less are crushed and produced, so as shown in FIGS. It is smooth and has excellent filling properties.
  • the average particle diameter can be measured, for example, with a laser diffraction particle size distribution analyzer (LA-950 manufactured by HORIBA).
  • LA-950 manufactured by HORIBA
  • D50 refers to a particle size whose cumulative number is 50% of the total number of particles. Note that, although not limited to this, approximately 3 to 200 columnar particles are aggregated in the ⁇ silicon nitride composite crystal.
  • the average particle diameter D50 is preferably 50 ⁇ m or more and 200 ⁇ m or less.
  • the average particle diameter D50 is preferably 20 ⁇ m or more and 170 ⁇ m or less, more preferably 25 ⁇ m or more and 160 ⁇ m or less, even more preferably 25 ⁇ m or more and 150 ⁇ m or less, and even more preferably 25 ⁇ m or more and 100 ⁇ m or less. It is preferably 25 ⁇ m or more and 80 ⁇ m or less, even more preferably 30 ⁇ m or more and 70 ⁇ m or less.
  • the silicon nitride filler of columnar particles described in each patent document is smaller than that of this embodiment. This is especially clear from the SEM photograph shown in FIG. 1 of Patent Document 2.
  • the ⁇ silicon nitride columnar particles in this embodiment have an aspect ratio of 0.05 or more and 0.6 or less as determined by SEM image analysis.
  • the aspect ratio was determined by observing with SEM (Phenom Prox), measuring the aspect ratio (breadth axis/long axis) of 400 particles using analysis software (Particle Metric), and using the average value thereof.
  • the short axis and the long axis can be determined by the length ratio of two sides of a substantially rectangular shape (rectangular shape) when the ⁇ silicon nitride columnar particle is viewed from the front.
  • the aspect ratio is preferably 0.1 or more and 0.5 or less, more preferably 0.11 or more and 0.5 or less, and even more preferably 0.11 or more and 0.45 or less.
  • columnar particles grow into a columnar shape having the above-mentioned average particle diameter D50 and aspect ratio by the combustion synthesis method, so that substantially rectangular planes occupy a large area and the particles Contact between surfaces increases, not only between surfaces but also between surfaces and lines. Thereby, a large number of heat paths can be formed and excellent thermal conductivity can be obtained.
  • the area of the plane (which can also be referred to as a flat surface or smooth surface) occupying the surface of the columnar particles is preferably 50% or more, more preferably 60% or more, and 70% or more of the total area. is more preferable, and most preferably 80% or more. Thereby, the above effects can be appropriately achieved. Note that the area occupied by the planes of the columnar powders in the Examples described later was all 80% or more.
  • the ⁇ silicon nitride columnar particles in this embodiment preferably have a D10 (cumulative 10% particle size) in the particle size distribution of 0.1 ⁇ m or more and 50 ⁇ m or less, more preferably 0.5 ⁇ m or more and 30 ⁇ m or less. , more preferably 0.7 ⁇ m or more and 20 ⁇ m or less, and even more preferably 1 ⁇ m or more and 15 ⁇ m or less.
  • the ⁇ silicon nitride columnar particles in this embodiment preferably have a D90 (90% cumulative particle size) of 60 ⁇ m or more and 300 ⁇ m or less in the particle size distribution, more preferably 60 ⁇ m or more and 200 ⁇ m or less, and 70 ⁇ m or more.
  • the number of particles to obtain the particle size distribution and aspect ratio of ⁇ silicon nitride columnar particles is preferably from several tens to several hundreds, specifically about 100 to 500. be. In the experiment described later, the number was 400.
  • the ⁇ -silicon nitride columnar particles are synthesized by a combustion synthesis method, so that the crystals do not contain impurities or can contain very few impurities. Therefore, the thermal conductivity of the ⁇ silicon nitride columnar particles is not impaired compared to silicon nitride fillers such as those disclosed in Patent Document 2 that contain flux.
  • the composite particles in this embodiment include the ⁇ silicon nitride columnar particles described above and the ⁇ silicon nitride pulverized particles, have an average particle diameter D50 of 5 ⁇ m or more and 150 ⁇ m or less, and have an aspect ratio determined by SEM image analysis. It is characterized by being 0.4 or more and 0.7 or less.
  • the method for measuring the average particle diameter D50 and aspect ratio is as explained in the section ⁇ silicon nitride columnar particles in this embodiment> above.
  • the ⁇ silicon nitride composite crystals shown in FIGS. 1A and 1B are synthesized by a combustion synthesis method, and this is crushed. At this time, columnar particles having an average particle diameter D50 of 10 ⁇ m or more and 200 ⁇ m or less are classified and collected. On the other hand, the agglomerated powder that is not recovered as ⁇ -silicon nitride columnar particles can be pulverized using a ball mill to obtain pulverized ⁇ -silicon nitride particles.
  • the average particle diameter D50 of the ⁇ silicon nitride pulverized particles is 50 ⁇ m or less, preferably 40 ⁇ m or less, more preferably 30 ⁇ m or less, and still more preferably 20 ⁇ m or less. , even more preferably 10 ⁇ m or less.
  • the average particle diameter D50 of the ⁇ silicon nitride pulverized particles is smaller than the average particle diameter D50 of the ⁇ silicon nitride columnar particles. In this way, by making the average particle diameter D50 of the ⁇ silicon nitride pulverized particles smaller than the average particle diameter D50 of the ⁇ silicon nitride columnar particles, the filling rate can be further increased.
  • FIG. 3A is a scanning electron micrograph of composite particles that are a mixture of columnar ⁇ silicon nitride particles and ground ⁇ silicon nitride particles.
  • the composite particles contain a mixture of ⁇ silicon nitride columnar particles and crushed ⁇ silicon nitride particles.
  • shape of the ⁇ silicon nitride pulverized particles is not limited, examples thereof include spherical, elliptical, polyhedral, and uneven shapes.
  • many of the ⁇ silicon nitride pulverized particles have a smaller particle size than the ⁇ silicon nitride columnar particles.
  • the D50 of the ⁇ silicon nitride columnar particles is smaller than the D50 of the ⁇ silicon nitride columnar particles.
  • it contains many single crystal particles (filler) (in other words, almost no agglomerated powder is found), and all of these particles have smooth particle surfaces and have poor filling properties. Excellent. That is, the surface of the ⁇ silicon nitride pulverized particles also has many flat portions, and the area ratio of flat surfaces is 30% or more, preferably 50% or more, and more preferably 70% or more.
  • the mixed particles of this embodiment include ⁇ silicon nitride columnar particles and ⁇ silicon nitride pulverized particles, so that the average particle diameter D50 and aspect ratio of the ⁇ silicon nitride columnar particles are smaller than the average particle diameter D50 and aspect ratio.
  • the ⁇ silicon nitride columnar particles or composite particles of this embodiment can be applied as a heat dissipation filler.
  • the average particle diameter D50 of the ⁇ silicon nitride columnar particles in this embodiment is as large as several tens of ⁇ m or several hundred ⁇ m, external orientation treatment such as magnetic field orientation or pressurized orientation is facilitated. Therefore, the ⁇ silicon nitride columnar particles shown in FIGS. 2A and 2B, or the composite particles obtained by mixing the ⁇ silicon nitride columnar particles and the ⁇ silicon nitride pulverized particles shown in FIGS. 3A and 3B, are particles for heat dissipation sintered substrates. It is useful as a seed crystal for orientation.
  • the average particle diameter D50 of the ⁇ silicon nitride columnar particles in this embodiment is as large as several tens or hundreds of ⁇ m, they can be used as a reinforcing material for resins and the like. That is, the ⁇ silicon nitride columnar particles of this embodiment are mixed into the resin. Thereby, effects such as improvement in the abrasion resistance and bending strength of the resin can be obtained. Further, for example, the beta silicon nitride columnar particles of this embodiment can be added to glass to be used as a ceramic reinforcing material to increase the strength of the glass. In this way, a resin composite or an inorganic composite containing the ⁇ silicon nitride columnar particles or composite particles in this embodiment can be manufactured.
  • ⁇ silicon nitride columnar particles shown in FIGS. 2A and 2B, or composite particles obtained by mixing ⁇ silicon nitride columnar particles and crushed ⁇ silicon nitride particles shown in FIGS. 3A and 3B are provided.
  • the ⁇ silicon nitride columnar particles in this embodiment are (1) A step of synthesizing ⁇ -silicon nitride composite crystals by a combustion synthesis method in a nitrogen atmosphere using raw materials containing Si; (2) Crushing the ⁇ -silicon nitride composite crystal to obtain columnar particles having an average particle diameter D50 of 10 ⁇ m or more and 200 ⁇ m or less, and an aspect ratio of 0.05 or more and 0.6 or less as determined by SEM image analysis. It is characterized by having a process.
  • ⁇ -silicon nitride composite crystals are synthesized by a combustion synthesis method.
  • ⁇ -silicon nitride grows in a columnar shape, and as shown in FIGS. 1A and 1B, a plurality of columnar It is said to have a structure in which particles are aggregated.
  • the AlN crystal grows equiaxed by the combustion synthesis method and does not grow columnar.
  • the average particle diameter D50 of Si used as the raw material is, for example, within the range of 2 to 10 ⁇ m. This makes it possible to suppress the amount of oxygen impurities, increase the combustion rate, increase the synthesis temperature, and obtain good crystal growth.
  • the average particle diameter D50 of Si is 5 ⁇ m.
  • the silicon nitride powder may be either ⁇ type or ⁇ type. Further, the average particle diameter D50 of the silicon nitride powder is preferably in the range of 0.1 to 5 ⁇ m. As an example, the average particle diameter D50 of silicon nitride powder is 1 ⁇ m.
  • the diluent is used to adjust the amount of Si in the raw material. The amount of diluent added is preferably within the range of 10% by mass to 50% by mass in the raw material. Thereby, welding of Si can be suppressed and combustion can be appropriately caused, and excellent crystal growth can be obtained with a sufficient amount of heat. As an example, the diluent is added to the raw material in an amount of 20% by mass.
  • a diluent is mixed into the raw materials, and the mixture is filled into an insulating heat-resistant container.
  • This heat-insulating heat-resistant container has a thermal conductivity of 1 W/mK or less, and the material can be alumina or zirconia, but carbon is preferable in consideration of contamination with impurities.
  • cover the container with a material similar to that of the heat-insulating heat-resistant container.
  • the thickness of the mixed raw material is set to 50 mm or more, preferably 100 mm or more. Note that if it is 400 mm or more, it will take time to cool down and increase manufacturing cost, so it is preferably 400 mm or less.
  • combustion synthesis is performed under a nitrogen atmosphere in the range of 0.5 to 1 MPa (for example, 0.9 MPa). By adjusting the pressure range within the above range, efficient synthesis can be achieved and an increase in equipment costs can be suppressed.
  • a catalyst may be used to more effectively promote crystal growth.
  • Y 2 O 3 , Fe 2 O 3 , CaO, Ni, Co, C, etc. are added in an amount of about 0.01 to 0.1% by mass.
  • similar columnar crystals can be obtained by a combustion synthesis method using self-ignition by performing external auxiliary heating in the range of 500° C. to 1700° C. (for example, 1500° C.) because the combustion temperature becomes higher.
  • the ⁇ -silicon nitride composite crystal is in the form of agglomerated columnar particles, so in the step (2) above, the ⁇ -silicon nitride composite crystal is crushed and classified. .
  • the crushing step for example, the composite is crushed using a general coarse crushing device such as a hammer mill or a disc mill until it passes through a sieve with an opening of 150 ⁇ m.
  • the columnar crystals are collected through a wedge wire with a 25 ⁇ m slit.
  • the collected columnar particles are passed through a sieve with an opening of 25 ⁇ m to remove any agglomerated powder with a diameter of 25 ⁇ m or less.
  • ⁇ silicon nitride columnar particles having an average particle diameter D50 of 10 ⁇ m or more and 200 ⁇ m or less and an aspect ratio of 0.05 or more and 0.6 or less as determined by SEM image analysis are obtained. Obtainable.
  • the method for producing ⁇ -silicon nitride columnar particles of the present embodiment involves simple steps such as synthesizing ⁇ -silicon nitride composite crystals using the heat of formation in the combustion synthesis method, and crushing and classifying the crystals. Through this process, ⁇ silicon nitride columnar particles having a larger average particle diameter D50 than conventional ones can be obtained. Therefore, ⁇ -silicon nitride columnar particles with high thermal conductivity and excellent filling properties can be manufactured with high productivity.
  • the combustion synthesis method enables energy-saving production and reduces production costs.
  • step (2) After extracting the ⁇ -silicon nitride columnar particles in step (2), pulverizing the unrecovered agglomerated powder to obtain pulverized ⁇ -silicon nitride particles; (4) By mixing ⁇ -silicon nitride columnar particles and ⁇ -silicon nitride pulverized particles (mixing ratio: 1:9 to 9:1), the average particle diameter D50 is 5 ⁇ m or more and 150 ⁇ m or less, and the result is determined by SEM image analysis. A step of obtaining composite particles having an aspect ratio of 0.4 or more and 0.7 or less.
  • the agglomerated powder removed in step (2) above is pulverized in step (3) above, for example, until the average particle diameter D50 becomes 10 ⁇ m or less.
  • the pulverization method is not limited, and a general rolling ball mill, planetary ball mill, vibrating ball mill, jet mill, etc. can be used. Note that the average particle diameter D50 to be pulverized can be variously selected depending on the purpose and the like.
  • the ⁇ silicon nitride pulverized particles obtained here have a shape other than columnar crystals, such as spherical or polyhedral, and have very smooth particle surfaces.
  • step (4) above in this embodiment, the ⁇ silicon nitride columnar particles obtained in step (2) above and the ground ⁇ silicon nitride particles obtained in step (3) above are mixed.
  • the ⁇ silicon nitride pulverized particles are smaller than the ⁇ silicon nitride columnar particles, and can be inserted between the ⁇ silicon nitride columnar particles and the ⁇ silicon nitride columnar particles to increase the filling rate.
  • particles have more surface-to-line contact than surface contact or point contact, which increases the number of heat paths and provides excellent thermal conductivity.
  • the ⁇ silicon nitride columnar particles obtained in step (2) above and the crushed ⁇ silicon nitride particles obtained in step (3) above are heated at 500° C. to 800° C. (for example, It is preferable to perform the heat treatment at a temperature of 600° C. in an air atmosphere. This is because an oxide film is attached to the particle surface to stabilize it and make it hydrophilic.
  • Two types of heat-treated powders are placed in water, stirred and mixed, and then subjected to wet classification. Wet classification includes sieve classification and specific gravity classification, and cyclone classification was used. Through this mixing process, it is possible to control the amount of columnar powder mixed in and create characteristics that suit the application. For example, if orientation is required for heat dissipation properties, the amount of columnar powder mixed is increased.
  • the ⁇ silicon nitride columnar particles of this embodiment have excellent thermal conductivity by adjusting the average particle diameter D50 and aspect ratio.
  • ⁇ silicon nitride columnar particles or composite particles are superior to AlN in terms of water resistance and thermal conductivity.
  • ⁇ silicon nitride columnar particles can be obtained by crushing ⁇ silicon nitride composite crystals as large crystals, ⁇ silicon nitride columnar particles having smooth planes, and ⁇ silicon nitride columnar particles obtained by crushing aggregated powder.
  • the crushed silicon nitride particles also have a smooth particle shape, and composite particles made by mixing these particles have excellent filling properties.
  • the composite particles also contain columnar crystals, they have an advantageous effect on the heat path and can improve thermal conductivity.
  • ⁇ silicon nitride columnar particles or composite particles in this embodiment can be used not only as a filler but also as a seed crystal or a resin reinforcing material for a sintered substrate.
  • the D50 of the columnar particles was found to be within the range of 10 ⁇ m to 200 ⁇ m, preferably within the range of 20 ⁇ m to 100 ⁇ m. Further, it has been found that the aspect ratio is within the range of 0.05 to 0.6, preferably within the range of 0.1 to 0.5.
  • Example 1 had an average particle diameter D50 of 5 ⁇ m
  • Example 2 had an average particle diameter D50 of 10 ⁇ m
  • Example 3 had an average particle diameter D50 of 20 ⁇ m.
  • FIGS. 3A and 3B are a SEM photograph and a partial schematic diagram of Example 3. Then, the aspect ratio and thermal conductivity of each example were measured. "Thermal conductivity" was measured by temperature wave measurement method (ai-Phase).
  • Comparative Examples 1 to 6 were prepared. Comparative Examples 1 to 3 are coarsely classified ⁇ silicon nitride particles obtained by conventional synthesis, Comparative Example 1 has an average particle diameter D50 of 5 ⁇ m, Comparative Example 2 has an average particle diameter D50 of 10 ⁇ m, and In No. 3, the average particle diameter D50 was 20 ⁇ m.
  • 4A and 4B are a SEM photograph and a partial schematic diagram of Comparative Example 3. Note that "normal synthesis” is a synthesis method that does not intend crystal growth, and uses a non-insulated crucible made of carbon, the dilution rate is 50 wt%, the gas pressure is 700 KPa, and the raw material size is the same as in the example. , the raw material layer thickness was 40 mm.
  • Comparative Examples 4 to 6 are AlN particles
  • Comparative Example 4 is an AlN filler with an average particle diameter D50 of 5 ⁇ m (AN-HF05LG-HTZ manufactured by Kabuki Gosei Co., Ltd.)
  • Comparative Example 5 is an AlN filler with an average particle diameter D50 of 5 ⁇ m.
  • Comparative Example 6 was an AlN filler with a particle diameter D50 of 10 ⁇ m (AN-HF10LG-HTZ, manufactured by Yasushi Gosei Co., Ltd.)
  • Comparative Example 6 was an AlN filler (AN-HF20LG-HTZ, manufactured by Yasushi Gosei Co., Ltd.) with an average particle diameter D50 of 20 ⁇ m. there were.
  • the experimental results are shown in Table 2 below.
  • Examples 1 to 3 were all able to obtain high thermal conductivity when compared with the same D50 as Comparative Examples 1 to 6. In addition, Examples 1 to 3 have smaller aspect ratios than Comparative Examples 1 to 6, confirming the characteristics of Examples 1 to 3 as composite particles of ⁇ silicon nitride columnar particles and ⁇ silicon nitride pulverized particles. did it.
  • the filling rate of the particles was varied from 46% by volume to 58% by volume, and the viscosity (25°C) at each filling rate was measured. Further, the viscosity was measured at 25° C. using a B-type viscometer. Note that when the tap density was measured, it was about 1.00 to 1.40 (g/cc) in the examples.
  • Example 3 As shown in Table 3, in Comparative Example 3, the filling rate reached the filling limit at 52% by volume, but in Example 3, the filling limit reached 58% by volume, and Example 3 was better than Comparative Example 3. It was found that the filling properties were excellent. In Example 3, both the ⁇ -silicon nitride columnar particles and the ⁇ -silicon nitride crushed particles had smooth flat surfaces (it was confirmed that they occupied more than 80% of the surface), and as a result, the filling properties were excellent, and the columnar particles also From Table 2, it was confirmed that the inclusion of the compound had an advantageous effect on the heat path and improved thermal conductivity.
  • the ⁇ silicon nitride columnar particles of the present invention have excellent water resistance and thermal conductivity, can be manufactured at low cost, and are effective not only as heat dissipation fillers but also as seed crystals for sintered substrates. It can be used for.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Ceramic Products (AREA)

Abstract

A purpose of the present invention is to provide columnar particles of β-silicon nitride excellent in terms of thermal conductivity and filling property, composite particles, a sintered substrate for heat radiation, a method for producing the columnar particles of β-silicon nitride, and a method for producing the composite particles. The columnar particles of β-silicon nitride according to the present invention are characterized by having an average particle diameter D50 of 10-200 μm and an aspect ratio, as determined by SEM image analysis, of 0.05-0.6. The composite particles according to the present invention are characterized by comprising the columnar particles of β-silicon nitride and pulverized particles of β-silicon nitride and by having an average particle diameter D50 of 5-150 μm and an aspect ratio, as determined by SEM image analysis, of 0.4-0.7.

Description

β窒化ケイ素柱状粒子、複合粒子、放熱用焼結基板、樹脂複合物、及び、無機複合物、並びに、β窒化ケイ素柱状粒子の製造方法、複合粒子の製造方法β-silicon nitride columnar particles, composite particles, sintered substrates for heat dissipation, resin composites, inorganic composites, methods for producing β-silicon nitride columnar particles, and methods for producing composite particles
　本発明は、β窒化ケイ素柱状粒子、複合粒子、放熱用焼結基板、樹脂複合物、及び、無機複合物、並びに、β窒化ケイ素柱状粒子の製造方法、複合粒子の製造方法に関する。 The present invention relates to β silicon nitride columnar particles, composite particles, a sintered substrate for heat dissipation, a resin composite, an inorganic composite, a method for producing β silicon nitride columnar particles, and a method for producing composite particles.
　一般的に使用される絶縁性無機フィラーには、アルミナや窒化ホウ素（ＢＮ）、窒化アルミニウム（ＡｌＮ）がある。このうち、アルミナは、安価で最も使用されている無機フィラーであるが、アルミナを用いた放熱材料では、熱伝導率を十分高めることができなかった。 Commonly used insulating inorganic fillers include alumina, boron nitride (BN), and aluminum nitride (AlN). Among these, alumina is the cheapest and most used inorganic filler, but heat dissipation materials using alumina have not been able to sufficiently increase thermal conductivity.
　特に、近年では、電気自動車や自動車の自動運転技術、ＡＩの高性能化による電子機器の発熱量増加、さらには、５Ｇによる高周波・高速・大容量通信などの理由により市場の放熱材料への要求仕様は益々高くなっている。
　例えば、特許文献に記載された窒化ケイ素は、高熱伝導性材料として挙げられている。 In particular, in recent years, there has been an increase in heat dissipation materials in the market due to reasons such as the increase in heat generation of electronic devices due to electric vehicles and self-driving technology of automobiles, the high performance of AI, and high frequency, high speed, and large capacity communication due to 5G. Specifications are getting higher and higher.
For example, silicon nitride, described in patent literature, is cited as a highly thermally conductive material.
特許第６２４５６０２号公報Patent No. 6245602 特開２００４－３５２５３９号公報Japanese Patent Application Publication No. 2004-352539 特許第６８４５４０２号公報Patent No. 6845402
　しかしながら、窒化ケイ素粒子は、充填性が非常に悪く、窒化ケイ素粒子を含む放熱材料の熱伝導率を十分高くできない問題があった。 However, silicon nitride particles have very poor filling properties, and there is a problem in that the thermal conductivity of a heat dissipating material containing silicon nitride particles cannot be made sufficiently high.
　また、焼結用材料としてα窒化ケイ素の販売量は多いが、β窒化ケイ素では焼結強度が十分でないこともあり、販売量が少なく用途も限定的とされていた。このため、β窒化ケイ素は、放熱フィラーとして十分期待された材料ではなかった。 In addition, although alpha silicon nitride has been sold in large quantities as a sintering material, beta silicon nitride has insufficient sintering strength, so its sales volume has been small and its uses have been limited. For this reason, β silicon nitride has not been a material that has been fully expected to be used as a heat dissipation filler.
　そこで、本発明は、上記問題に鑑みてなされたもので、熱伝導性及び充填性に優れたβ窒化ケイ素柱状粒子、複合粒子、放熱用焼結基板、樹脂複合物、及び、無機複合物、並びに、β窒化ケイ素柱状粒子の製造方法、複合粒子の製造方法を提供することを目的とする。 Therefore, the present invention was made in view of the above problems, and includes β silicon nitride columnar particles, composite particles, a sintered substrate for heat dissipation, a resin composite, and an inorganic composite, which have excellent thermal conductivity and filling properties. Another object of the present invention is to provide a method for producing β-silicon nitride columnar particles and a method for producing composite particles.
　本発明におけるβ窒化ケイ素柱状粒子は、平均粒子径Ｄ５０が、１０μｍ以上２００μｍ以下の柱状粒子であり、ＳＥＭ画像解析によるアスペクト比が、０．０５以上０．６以下である、ことを特徴とする。
　本発明では、前記平均粒子径Ｄ５０が、２５μｍ以上１００μｍ以下であることが好ましい。 The β silicon nitride columnar particles in the present invention are columnar particles with an average particle diameter D50 of 10 μm or more and 200 μm or less, and have an aspect ratio of 0.05 or more and 0.6 or less as determined by SEM image analysis. .
In the present invention, the average particle diameter D50 is preferably 25 μm or more and 100 μm or less.
　また、本発明における複合粒子は、上記に記載のβ窒化ケイ素柱状粒子と、β窒化ケイ素粉砕粒子とを含み、平均粒子径Ｄ５０が、５μｍ以上１５０μｍ以下であり、ＳＥＭ画像解析によるアスペクト比が、０．４以上０．７以下である、ことを特徴とする。 Further, the composite particles in the present invention include the β silicon nitride columnar particles described above and the β silicon nitride pulverized particles, have an average particle diameter D50 of 5 μm or more and 150 μm or less, and have an aspect ratio determined by SEM image analysis. It is characterized by being 0.4 or more and 0.7 or less.
　また、本発明における放熱用焼結基板は、上記に記載のβ窒化ケイ素柱状粒子、あるいは、上記に記載の複合粒子を焼成してなる、ことを特徴とする。
　また、本発明における樹脂複合物は、上記に記載のβ窒化ケイ素柱状粒子、あるいは、上記に記載の複合粒子を含む、ことを特徴とする。
　また、本発明における無機複合物は、上記に記載のβ窒化ケイ素柱状粒子、あるいは、上記に記載の複合粒子を含む、ことを特徴とする。 Moreover, the sintered substrate for heat dissipation in the present invention is characterized by being formed by firing the β silicon nitride columnar particles described above or the composite particles described above.
Furthermore, the resin composite in the present invention is characterized by containing the β silicon nitride columnar particles described above or the composite particles described above.
Further, the inorganic composite in the present invention is characterized by containing the β silicon nitride columnar particles described above or the composite particles described above.
　また、本発明におけるβ窒化ケイ素柱状粒子の製造方法は、Ｓｉを含む原料を用いて、窒素雰囲気下にて燃焼合成法により、β窒化ケイ素合成体結晶を合成し、前記β窒化ケイ素合成体結晶を解砕・分級して、平均粒子径Ｄ５０が、１０μｍ以上２００μｍ以下であり、ＳＥＭ画像解析によるアスペクト比が、０．０５以上０．６以下である柱状粒子を得る、ことを特徴とする。 Further, the method for producing β-silicon nitride columnar particles in the present invention includes synthesizing β-silicon nitride composite crystals by a combustion synthesis method in a nitrogen atmosphere using a raw material containing Si; is crushed and classified to obtain columnar particles having an average particle diameter D50 of 10 μm or more and 200 μm or less, and an aspect ratio of 0.05 or more and 0.6 or less as determined by SEM image analysis.
　また、本発明における複合粒子の製造方法は、上記にて記載のβ窒化ケイ素柱状粒子を抽出した後の凝集紛を粉砕して、β窒化ケイ素粉砕粒子を得た後、前記β窒化ケイ素柱状粒子と前記β窒化ケイ素粉砕粒子とを混合して、平均粒子径Ｄ５０が、５μｍ以上１５０μｍ以下であり、ＳＥＭ画像解析によるアスペクト比が、０．４以上０．７以下である複合粒子を得る、ことを特徴とする。 Further, the method for producing composite particles in the present invention includes crushing the agglomerated powder after extracting the β silicon nitride columnar particles described above to obtain crushed β silicon nitride particles, and then grinding the β silicon nitride columnar particles. and the β silicon nitride pulverized particles to obtain composite particles having an average particle diameter D50 of 5 μm or more and 150 μm or less, and an aspect ratio of 0.4 or more and 0.7 or less as determined by SEM image analysis. It is characterized by
　本発明のβ窒化ケイ素柱状粒子によれば、ＡｌＮに比べて耐水性であり、熱伝導性でも優れている。また充填率を上げることができ、放熱フィラーとして、あるいは焼結基板の種結晶など様々な用途に実用化が可能である。 According to the β silicon nitride columnar particles of the present invention, they have better water resistance and thermal conductivity than AlN. Furthermore, the filling rate can be increased, and it can be put to practical use in a variety of applications, such as as a heat dissipation filler or as a seed crystal for sintered substrates.
図１Ａは、β窒化ケイ素合成体結晶の走査電子顕微鏡写真である。FIG. 1A is a scanning electron micrograph of a β-silicon nitride composite crystal. 図１Ｂは、図１Ａの部分模式図である。FIG. 1B is a partial schematic diagram of FIG. 1A. 図２Ａは、β窒化ケイ素柱粒子の走査電子顕微鏡写真である。FIG. 2A is a scanning electron micrograph of beta silicon nitride columnar particles. 図２Ｂは、図２Ａの部分模式図である。FIG. 2B is a partial schematic diagram of FIG. 2A. 図３Ａは、実施例３（Ｄ５０＝２０μｍ）の走査電子顕微鏡写真である。FIG. 3A is a scanning electron micrograph of Example 3 (D50=20 μm). 図３Ｂは、図３Ａの部分模式図である。FIG. 3B is a partial schematic diagram of FIG. 3A. 図４Ａは、比較例３（Ｄ５０＝２０μｍ）の走査電子顕微鏡写真である。FIG. 4A is a scanning electron micrograph of Comparative Example 3 (D50=20 μm). 図４Ｂは、図４Ａの部分模式図である。FIG. 4B is a partial schematic diagram of FIG. 4A.
　以下、本発明の一実施の形態（以下、「実施の形態」と略記する。）について、詳細に説明する。なお、本発明は、以下の実施の形態に限定されるものではなく、その要旨の範囲内で種々変形して実施することができる。なお、「～」の表記は、下限値及び上限値の双方の数値を含む。 Hereinafter, one embodiment of the present invention (hereinafter abbreviated as "embodiment") will be described in detail. Note that the present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist. Note that the notation "~" includes both the lower limit value and the upper limit value.
＜特許文献および非特許文献に挙げられた窒化ケイ素フィラーの問題点＞
　特許文献１に記載された窒化ケイ素フィラーは、柱状形状の窒化ケイ素粒子を含む凝結粒子である。このような窒化ケイ素フィラーは、燃焼合成法で容易に得られる形状であり、生産性に優れるものの、柱状粒子が凝集した形状であるため、フィラー表面に凹凸や穴が存在する。このため比表面積が非常に大きくなり、充填性に課題がある。 <Problems with silicon nitride fillers listed in patent literature and non-patent literature>
The silicon nitride filler described in Patent Document 1 is agglomerated particles containing columnar silicon nitride particles. Although such a silicon nitride filler has a shape that can be easily obtained by combustion synthesis and has excellent productivity, since it has a shape in which columnar particles are aggregated, irregularities and holes are present on the filler surface. For this reason, the specific surface area becomes very large, and there is a problem with filling properties.
　特許文献２に記載された棒状窒化ケイ素フィラーは、窒化ケイ素粉末を、フラックス中で熱処理した後、アルカリ溶液処理と酸溶液処理を繰り返してフラックス成分を溶解して生成される。例えば、フラック成分と窒化ケイ素の混合体を、窒素またはアルゴン雰囲気下で、１６００℃～１９００℃という高温で熱処理を行い、その後アルカリと酸による洗浄処理を複数回行い、棒状窒化ケイ素フィラーを得る方法が提案されている。しかしながら、製造工程が複雑であり、生産コストが高くなる。また、フラックス成分や酸素が窒化ケイ素結晶内に固溶され、窒化ケイ素フィラー本来の熱伝導特性が損なわれる可能性が考えられる。特に、特許文献２は、耐食性の高い窒化ケイ素焼結体を形成し、粒界を溶かして柱状晶を得る方法であり非現実的な方法である。また、特許文献２には記載されていないが、平均粒子径Ｄ５０はかなり小さくなるものと予測される。 The rod-shaped silicon nitride filler described in Patent Document 2 is produced by heat-treating silicon nitride powder in flux and then repeating alkaline solution treatment and acid solution treatment to dissolve the flux component. For example, a method in which a mixture of a frac component and silicon nitride is heat-treated at a high temperature of 1,600 to 1,900 degrees Celsius in a nitrogen or argon atmosphere, and then washed with alkali and acid multiple times to obtain a rod-shaped silicon nitride filler. is proposed. However, the manufacturing process is complicated and production costs are high. Furthermore, there is a possibility that the flux components and oxygen are dissolved in the silicon nitride crystal, impairing the inherent thermal conductivity properties of the silicon nitride filler. In particular, Patent Document 2 is an unrealistic method in which a highly corrosion-resistant silicon nitride sintered body is formed and grain boundaries are melted to obtain columnar crystals. Further, although it is not described in Patent Document 2, the average particle diameter D50 is expected to be considerably small.
　特許文献３には、磁気異方性粒子（Ａ）と、種粒子（Ｂ）からなる複合粒子（Ｃ）を有する結晶配向セラミックスに関する発明が開示されており、種粒子（Ｂ）に、β窒化ケイ素が選択される。しかしながら、特許文献３に記載の構成では、生産コストが高く実用化が困難である。また、平均粒子径Ｄ５０が非常に小さく、配向効果も低いといった課題もある。 Patent Document 3 discloses an invention relating to crystal-oriented ceramics having composite particles (C) consisting of magnetically anisotropic particles (A) and seed particles (B), in which the seed particles (B) have β-nitrided Silicon is chosen. However, the configuration described in Patent Document 3 has high production costs and is difficult to put into practical use. Further, there are also problems in that the average particle diameter D50 is very small and the orientation effect is also low.
　非特許文献１では、窒化ケイ素ナノワイヤーを、還元窒化法にて製造する方法が示されている。この方法では、ＳｉＯ２に金属触媒と炭素を加え、０．９５ＭＰａの窒素雰囲気で、１８５０℃及び１０時間保持して製造する方法が提案されている。しかしながら、非特許文献１では、結晶の太さが１μｍ以下と非常に小さく、熱の伝達効率が悪く、不純物も含まれる。また、高温高圧雰囲気下を長時間保持する必要があり、特殊設備が必要でありコストが高い課題がある。 Non-Patent Document 1 discloses a method of manufacturing silicon nitride nanowires by a reductive nitriding method. In this method, a method has been proposed in which a metal catalyst and carbon are added to SiO 2 and the mixture is maintained at 1850° C. for 10 hours in a nitrogen atmosphere of 0.95 MPa. However, in Non-Patent Document 1, the crystal thickness is very small, 1 μm or less, has poor heat transfer efficiency, and contains impurities. In addition, it is necessary to maintain a high-temperature, high-pressure atmosphere for a long time, and special equipment is required, resulting in high costs.
　また、非特許文献２では、βＳｉ３Ｎ４を種結晶として添加し、焼結体を形成している。このとき、焼結を０．９ＭＰａの窒素雰囲気で、１８５０℃及び６時間保持して製造する方法が提案されている。しかしながら、高温高圧雰囲気下を長時間保持する必要があり、特殊設備が必要でありコストが高い課題がある。また、種結晶から柱状粒子に成長するが、柱状粒子のサイズは非常に小さく、配向効果が低い課題もある。 Furthermore, in Non-Patent Document 2, βSi 3 N 4 is added as a seed crystal to form a sintered body. At this time, a method has been proposed in which sintering is carried out in a nitrogen atmosphere of 0.9 MPa and maintained at 1850° C. for 6 hours. However, it is necessary to maintain a high-temperature, high-pressure atmosphere for a long time, and special equipment is required, leading to high costs. Further, although columnar particles grow from seed crystals, the size of the columnar particles is very small, and there is also the problem that the orientation effect is low.
＜本実施の形態におけるβ窒化ケイ素柱状粒子＞
　本実施の形態におけるβ窒化ケイ素柱状粒子は、平均粒子径Ｄ５０が、１０μｍ以上２００μｍ以下の柱状粒子であり、ＳＥＭ画像解析によるアスペクト比が、０．０５以上０．６以下である、ことを特徴とする。 <β silicon nitride columnar particles in this embodiment>
The β silicon nitride columnar particles in this embodiment are columnar particles with an average particle diameter D50 of 10 μm or more and 200 μm or less, and an aspect ratio determined by SEM image analysis of 0.05 or more and 0.6 or less. shall be.
　本実施の形態のβ窒化ケイ素柱状粒子は、燃焼合成法の生成熱を利用して合成されたものである。図１Ａは、β窒化ケイ素合成体結晶の走査電子顕微鏡（ＳＥＭ）写真である。図１Ｂは、図１Ａの部分模式図である。図１Ａ、図１Ｂに示すように、燃焼合成法により生成されたβ窒化ケイ素合成体結晶（多結晶体）は、多数の柱状粒子（柱状フィラー）が凝集した状態であり、これを解砕し分級することで、平均粒子径Ｄ５０が、１０μｍ以上２００μｍ以下の柱状粒子を得ることができる（図２Ａ、図２Ｂ参照）。このように、１０μｍ以上２００μｍ以下の多数の柱状粒子からなる柱状結晶を解砕して作製するため、図２Ａ、図２Ｂに示すように単結晶の結晶粒子（フィラー）を多く含み、粒子表面が滑らかであり、充填性に優れる。平均粒子径は、例えば、レーザ回折粒度分布測定装置（ＨＯＲＩＢＡ製　ＬＡ－９５０）にて測定することができる。「Ｄ５０」とは、累積個数が、全粒子数の５０％となる粒径を指す。なお、限定するものではないが、β窒化ケイ素合成体結晶には、３～２００個程度の柱状粒子が凝集している。 The β-silicon nitride columnar particles of this embodiment are synthesized using the heat generated by the combustion synthesis method. FIG. 1A is a scanning electron microscope (SEM) photograph of a β-silicon nitride composite crystal. FIG. 1B is a partial schematic diagram of FIG. 1A. As shown in FIGS. 1A and 1B, the β silicon nitride composite crystal (polycrystal) produced by the combustion synthesis method is a state in which many columnar particles (column filler) are aggregated, and this is crushed. By classifying, columnar particles having an average particle diameter D50 of 10 μm or more and 200 μm or less can be obtained (see FIGS. 2A and 2B). In this way, columnar crystals consisting of many columnar particles with a size of 10 μm or more and 200 μm or less are crushed and produced, so as shown in FIGS. It is smooth and has excellent filling properties. The average particle diameter can be measured, for example, with a laser diffraction particle size distribution analyzer (LA-950 manufactured by HORIBA). "D50" refers to a particle size whose cumulative number is 50% of the total number of particles. Note that, although not limited to this, approximately 3 to 200 columnar particles are aggregated in the β silicon nitride composite crystal.
　本実施の形態では、平均粒子径Ｄ５０が、５０μｍ以上２００μｍ以下であることが好ましい。あるいは、平均粒子径Ｄ５０は、２０μｍ以上１７０μｍ以下であることが好ましく、２５μｍ以上１６０μｍ以下であることがより好ましく、２５μｍ以上１５０μｍ以下であることがさらに好ましく、２５μｍ以上１００μｍ以下であることがさらにより好ましく、２５μｍ以上８０μｍ以下であることがさらにより好ましく、３０μｍ以上７０μｍ以下であることがさらにより好ましい。例えば、各特許文献に記載の柱状粒子の窒化ケイ素フィラーは本実施の形態よりも小さい。特に、特許文献２の図１に示すＳＥＭ写真などから明らかである。 In this embodiment, the average particle diameter D50 is preferably 50 μm or more and 200 μm or less. Alternatively, the average particle diameter D50 is preferably 20 μm or more and 170 μm or less, more preferably 25 μm or more and 160 μm or less, even more preferably 25 μm or more and 150 μm or less, and even more preferably 25 μm or more and 100 μm or less. It is preferably 25 μm or more and 80 μm or less, even more preferably 30 μm or more and 70 μm or less. For example, the silicon nitride filler of columnar particles described in each patent document is smaller than that of this embodiment. This is especially clear from the SEM photograph shown in FIG. 1 of Patent Document 2.
　また、本実施の形態におけるβ窒化ケイ素柱状粒子は、ＳＥＭ画像解析によるアスペクト比が、０．０５以上０．６以下である。アスペクト比は、ＳＥＭ（Ｐｈｅｎｏｍ　Ｐｒｏｘ）により観察を行い、解析ソフト（Ｐａｒｔｉｃｌｅ　Ｍｅｔｒｉｃ）にて、４００個の粒子のアスペクト比（短径／長径）を測定し、その平均値で求めた。短径及び長径は、β窒化ケイ素柱状粒子を正面から見た略長方形状（矩形状）の２辺の長さ比で求めることができる。アスペクト比は、０．１以上０．５以下であることが好ましく、０．１１以上０．５以下であることがより好ましく、０．１１以上０．４５以下であることがさらに好ましい。図２Ａ、図２Ｂに示すように柱状粒子は、燃焼合成法により、上記した平均粒子径Ｄ５０及びアスペクト比を有する柱状に成長することで、略矩形状的な平面が多くの面積を占め、粒子同士の接触は、面同士のみならず、面と線との接触も増える。これにより、多数の熱パスを形成でき、優れた熱伝導性を得ることができる。 Further, the β silicon nitride columnar particles in this embodiment have an aspect ratio of 0.05 or more and 0.6 or less as determined by SEM image analysis. The aspect ratio was determined by observing with SEM (Phenom Prox), measuring the aspect ratio (breadth axis/long axis) of 400 particles using analysis software (Particle Metric), and using the average value thereof. The short axis and the long axis can be determined by the length ratio of two sides of a substantially rectangular shape (rectangular shape) when the β silicon nitride columnar particle is viewed from the front. The aspect ratio is preferably 0.1 or more and 0.5 or less, more preferably 0.11 or more and 0.5 or less, and even more preferably 0.11 or more and 0.45 or less. As shown in FIGS. 2A and 2B, columnar particles grow into a columnar shape having the above-mentioned average particle diameter D50 and aspect ratio by the combustion synthesis method, so that substantially rectangular planes occupy a large area and the particles Contact between surfaces increases, not only between surfaces but also between surfaces and lines. Thereby, a large number of heat paths can be formed and excellent thermal conductivity can be obtained.
　柱状粒子の表面に占める平面（平坦面、平滑面と言い換えるこもできる）の面積は、全面積の５０％以上であることが好ましく、６０％以上であることがより好ましく、７０％以上であることがさらに好ましく、８０％以上であることが最も好ましい。これにより、上記の効果を適切に奏することができる。なお後述する実施例の柱状粉末の平面が占める面積はすべて８０％以上であった。 The area of the plane (which can also be referred to as a flat surface or smooth surface) occupying the surface of the columnar particles is preferably 50% or more, more preferably 60% or more, and 70% or more of the total area. is more preferable, and most preferably 80% or more. Thereby, the above effects can be appropriately achieved. Note that the area occupied by the planes of the columnar powders in the Examples described later was all 80% or more.
　本実施の形態におけるβ窒化ケイ素柱状粒子は、粒度分布におけるＤ１０（累積１０％の粒径）が、０．１μｍ以上５０μｍ以下であることが好ましく、０．５μｍ以上３０μｍ以下であることがより好ましく、０．７μｍ以上２０μｍ以下であることがさらに好ましく、１μｍ以上１５μｍ以下であることがさらにより好ましい。また、本実施の形態におけるβ窒化ケイ素柱状粒子は、粒度分布におけるＤ９０（累積９０％の粒径）が、６０μｍ以上３００μｍ以下であることが好ましく、６０μｍ以上２００μｍ以下であることがより好ましく、７０μｍ以上１５０μｍ以下であることがさらに好ましく、８０μｍ以上１５０μｍ以下であることがさらにより好ましい。Ｄ１０、Ｄ５０、Ｄ９０の各範囲を調整することで、β窒化ケイ素柱状粒子の好ましい粒度分布、すなわち充填性などに優れた粒度分布を得ることができる。 The β silicon nitride columnar particles in this embodiment preferably have a D10 (cumulative 10% particle size) in the particle size distribution of 0.1 μm or more and 50 μm or less, more preferably 0.5 μm or more and 30 μm or less. , more preferably 0.7 μm or more and 20 μm or less, and even more preferably 1 μm or more and 15 μm or less. Further, the β silicon nitride columnar particles in this embodiment preferably have a D90 (90% cumulative particle size) of 60 μm or more and 300 μm or less in the particle size distribution, more preferably 60 μm or more and 200 μm or less, and 70 μm or more. It is more preferably not less than 150 μm, and even more preferably not less than 80 μm and not more than 150 μm. By adjusting each range of D10, D50, and D90, it is possible to obtain a preferable particle size distribution of the β silicon nitride columnar particles, that is, a particle size distribution with excellent filling properties.
　限定するものではないが、β窒化ケイ素柱状粒子の粒度分布及びアスペクト比を得るための粒子数は、数十個～数百個であることが好ましく、具体的には１００個～５００個程度である。後述する実験では、４００個とした。 Although not limited to, the number of particles to obtain the particle size distribution and aspect ratio of β silicon nitride columnar particles is preferably from several tens to several hundreds, specifically about 100 to 500. be. In the experiment described later, the number was 400.
　本実施の形態では、β窒化ケイ素柱状粒子を燃焼合成法により合成するため、結晶内に不純物を含まず、あるいは不純物をきわめて少なくできる。このため、フラックスを含む特許文献２などの窒化ケイ素フィラーなどに比べてβ窒化ケイ素柱状粒子の熱伝導性が損なわれない。 In this embodiment, the β-silicon nitride columnar particles are synthesized by a combustion synthesis method, so that the crystals do not contain impurities or can contain very few impurities. Therefore, the thermal conductivity of the β silicon nitride columnar particles is not impaired compared to silicon nitride fillers such as those disclosed in Patent Document 2 that contain flux.
＜本実施の形態における複合粒子＞
　本実施の形態における複合粒子は、上記に記載のβ窒化ケイ素柱状粒子と、β窒化ケイ素粉砕粒子とを含み、平均粒子径Ｄ５０が、５μｍ以上１５０μｍ以下であり、ＳＥＭ画像解析によるアスペクト比が、０．４以上０．７以下であることを特徴とする。平均粒子径Ｄ５０及びアスペクト比の測定方法は、上記の＜本実施の形態におけるβ窒化ケイ素柱状粒子＞欄で説明した通りである。 <Composite particles in this embodiment>
The composite particles in this embodiment include the β silicon nitride columnar particles described above and the β silicon nitride pulverized particles, have an average particle diameter D50 of 5 μm or more and 150 μm or less, and have an aspect ratio determined by SEM image analysis. It is characterized by being 0.4 or more and 0.7 or less. The method for measuring the average particle diameter D50 and aspect ratio is as explained in the section <β silicon nitride columnar particles in this embodiment> above.
　本実施の形態では、燃焼合成法により、図１Ａ、図１Ｂに示すβ窒化ケイ素合成体結晶を合成し、これを解砕する。このとき、平均粒子径Ｄ５０が、１０μｍ以上２００μｍ以下の柱状粒子は分級され回収される。一方、β窒化ケイ素柱状粒子として回収されなかった凝集紛をボールミルにより粉砕し、β窒化ケイ素粉砕粒子を得ることができる。限定されるものではないが、例えば、β窒化ケイ素粉砕粒子の平均粒子径Ｄ５０は、５０μｍ以下であり、好ましくは４０μｍ以下であり、より好ましくは３０μｍ以下であり、さらに好ましくは、２０μｍ以下であり、さらにより好ましくは１０μｍ以下である。限定されるものではないが、β窒化ケイ素粉砕粒子の平均粒子径Ｄ５０は、β窒化ケイ素柱状粒子の平均粒子径Ｄ５０より小さい。このようにβ窒化ケイ素粉砕粒子の平均粒子径Ｄ５０を、β窒化ケイ素柱状粒子の平均粒子径Ｄ５０より小さくすると、より一層充填率を上げることができる。 In this embodiment, the β silicon nitride composite crystals shown in FIGS. 1A and 1B are synthesized by a combustion synthesis method, and this is crushed. At this time, columnar particles having an average particle diameter D50 of 10 μm or more and 200 μm or less are classified and collected. On the other hand, the agglomerated powder that is not recovered as β-silicon nitride columnar particles can be pulverized using a ball mill to obtain pulverized β-silicon nitride particles. Although not limited, for example, the average particle diameter D50 of the β silicon nitride pulverized particles is 50 μm or less, preferably 40 μm or less, more preferably 30 μm or less, and still more preferably 20 μm or less. , even more preferably 10 μm or less. Although not limited to this, the average particle diameter D50 of the β silicon nitride pulverized particles is smaller than the average particle diameter D50 of the β silicon nitride columnar particles. In this way, by making the average particle diameter D50 of the β silicon nitride pulverized particles smaller than the average particle diameter D50 of the β silicon nitride columnar particles, the filling rate can be further increased.
　図３Ａは、β窒化ケイ素柱状粒子と、β窒化ケイ素粉砕粒子とを混合した複合粒子の走査電子顕微鏡写真である。図３Ｂは、図３Ａの部分模式図である。なお、図３Ａ、図３Ｂは、後述する実施例３（Ｄ５０＝２０μｍ）の走査電子顕微鏡写真である。 FIG. 3A is a scanning electron micrograph of composite particles that are a mixture of columnar β silicon nitride particles and ground β silicon nitride particles. FIG. 3B is a partial schematic diagram of FIG. 3A. Note that FIGS. 3A and 3B are scanning electron micrographs of Example 3 (D50=20 μm), which will be described later.
　図３Ａ、図３Ｂに示すように、複合粒子には、β窒化ケイ素柱状粒子と、β窒化ケイ素粉砕粒子とが混合されていることが明らかである。β窒化ケイ素粉砕粒子の形状を限定するものではないが、球状、楕円状、多面体、凹凸状などを例示できる。また、図３Ａ、図３Ｂに示すように、β窒化ケイ素粉砕粒子は、β窒化ケイ素柱状粒子より粒径の小さいものが多い。β窒化ケイ素柱状粒子のＤ５０と、β窒化ケイ素粉砕粒子のＤ５０とを対比すると、β窒化ケイ素粉砕粒子のＤ５０のほうがβ窒化ケイ素柱状粒子のＤ５０より小さくなっている。また、図３Ａ、図３Ｂに示すように、単結晶の結晶粒子（フィラー）を多く含んでおり（すなわち凝集紛はほとんど見当たらない）、これら粒子はいずれも粒子表面が滑らかであり、充填性に優れる。すなわち、β窒化ケイ素粉砕粒子の表面も平面部分が多くみられ、平面の面積比率は３０％以上であり、好ましくは５０％以上、より好ましく７０％以上である。 As shown in FIGS. 3A and 3B, it is clear that the composite particles contain a mixture of β silicon nitride columnar particles and crushed β silicon nitride particles. Although the shape of the β silicon nitride pulverized particles is not limited, examples thereof include spherical, elliptical, polyhedral, and uneven shapes. Further, as shown in FIGS. 3A and 3B, many of the β silicon nitride pulverized particles have a smaller particle size than the β silicon nitride columnar particles. Comparing the D50 of the β silicon nitride columnar particles with the D50 of the β silicon nitride pulverized particles, the D50 of the β silicon nitride pulverized particles is smaller than the D50 of the β silicon nitride columnar particles. In addition, as shown in Figures 3A and 3B, it contains many single crystal particles (filler) (in other words, almost no agglomerated powder is found), and all of these particles have smooth particle surfaces and have poor filling properties. Excellent. That is, the surface of the β silicon nitride pulverized particles also has many flat portions, and the area ratio of flat surfaces is 30% or more, preferably 50% or more, and more preferably 70% or more.
　本実施の形態の混合粒子は、β窒化ケイ素柱状粒子と、β窒化ケイ素粉砕粒子とを含むことで、β窒化ケイ素柱状粒子の平均粒子径Ｄ５０及びアスペクト比より小さくなるが、本実施の形態では、β窒化ケイ素柱状粒子と、β窒化ケイ素粉砕粒子との混合比を適宜調整することで、用途に合わせた性能を引き出すことができる。 The mixed particles of this embodiment include β silicon nitride columnar particles and β silicon nitride pulverized particles, so that the average particle diameter D50 and aspect ratio of the β silicon nitride columnar particles are smaller than the average particle diameter D50 and aspect ratio. By appropriately adjusting the mixing ratio of the β-silicon nitride columnar particles and the β-silicon nitride pulverized particles, performance tailored to the application can be obtained.
＜用途＞
　本実施の形態のβ窒化ケイ素柱状粒子、あるいは複合粒子は、放熱フィラーとして適用できる。 <Application>
The β silicon nitride columnar particles or composite particles of this embodiment can be applied as a heat dissipation filler.
　また、本実施の形態におけるβ窒化ケイ素柱状粒子の平均粒子径Ｄ５０は、数十μｍあるいは数百μｍと大きいため、磁場配向や加圧配向などの外部からの配向処理が容易となる。そのため、図２Ａ、図２Ｂに示すβ窒化ケイ素柱状粒子、あるいは図３Ａ、図３Ｂに示すβ窒化ケイ素柱状粒子とβ窒化ケイ素粉砕粒子とを混合した複合粒子は、放熱用焼結基板向けの粒子配向用種結晶として有用である。 Furthermore, since the average particle diameter D50 of the β silicon nitride columnar particles in this embodiment is as large as several tens of μm or several hundred μm, external orientation treatment such as magnetic field orientation or pressurized orientation is facilitated. Therefore, the β silicon nitride columnar particles shown in FIGS. 2A and 2B, or the composite particles obtained by mixing the β silicon nitride columnar particles and the β silicon nitride pulverized particles shown in FIGS. 3A and 3B, are particles for heat dissipation sintered substrates. It is useful as a seed crystal for orientation.
　また、本実施の形態におけるβ窒化ケイ素柱状粒子の平均粒子径Ｄ５０は、数十μｍあるいは数百μｍと大きいため、樹脂などに対する補強材として使用できる。すなわち樹脂中に本実施の形態のβ窒化ケイ素柱状粒子を混合する。これにより、樹脂の耐摩耗性や曲げ強度の向上などの効果を得ることができる。また、例えば、ガラスに本実施の形態のβ窒化ケイ素柱状粒子を入れてガラス強度を上げるためのセラミックス補強材としても適用できる。このように、本実施の形態におけるβ窒化ケイ素柱状粒子あるいは、複合粒子を含む樹脂複合物や無機複合物を製造することができる。 Furthermore, since the average particle diameter D50 of the β silicon nitride columnar particles in this embodiment is as large as several tens or hundreds of μm, they can be used as a reinforcing material for resins and the like. That is, the β silicon nitride columnar particles of this embodiment are mixed into the resin. Thereby, effects such as improvement in the abrasion resistance and bending strength of the resin can be obtained. Further, for example, the beta silicon nitride columnar particles of this embodiment can be added to glass to be used as a ceramic reinforcing material to increase the strength of the glass. In this way, a resin composite or an inorganic composite containing the β silicon nitride columnar particles or composite particles in this embodiment can be manufactured.
　なお、本実施の形態では、図２Ａ、図２Ｂに示すβ窒化ケイ素柱状粒子、あるいは図３Ａ、図３Ｂに示すβ窒化ケイ素柱状粒子とβ窒化ケイ素粉砕粒子とを混合した複合粒子を提供するが、β窒化ケイ素以外の組成からなる粒子（例えば、α窒化ケイ素）を１種以上含んでいてもよい。したがって上記の放熱用焼結基板には、β窒化ケイ素柱状粒子、あるいは、β窒化ケイ素柱状粒子とβ窒化ケイ素粉砕粒子とを混合した複合粒子とともに、例えば、α窒化ケイ素粒子などを含めることができる。 Note that in this embodiment, β silicon nitride columnar particles shown in FIGS. 2A and 2B, or composite particles obtained by mixing β silicon nitride columnar particles and crushed β silicon nitride particles shown in FIGS. 3A and 3B are provided. , may contain one or more particles having a composition other than β silicon nitride (for example, α silicon nitride). Therefore, the above-mentioned sintered substrate for heat dissipation can contain, for example, α silicon nitride particles together with β silicon nitride columnar particles or composite particles obtained by mixing β silicon nitride columnar particles and β silicon nitride pulverized particles. .
＜本実施の形態のβ窒化ケイ素柱状粒子及び、複合粒子の製造方法＞
　本実施の形態におけるβ窒化ケイ素柱状粒子は、
（１）　Ｓｉを含む原料を用いて、窒素雰囲気下にて燃焼合成法により、β窒化ケイ素合成体結晶を合成する工程、
（２）　β窒化ケイ素合成体結晶を解砕して、平均粒子径Ｄ５０が、１０μｍ以上２００μｍ以下であり、ＳＥＭ画像解析によるアスペクト比が、０．０５以上０．６以下である柱状粒子を得る工程、を有することを特徴とする。 <Production method of β silicon nitride columnar particles and composite particles of the present embodiment>
The β silicon nitride columnar particles in this embodiment are
(1) A step of synthesizing β-silicon nitride composite crystals by a combustion synthesis method in a nitrogen atmosphere using raw materials containing Si;
(2) Crushing the β-silicon nitride composite crystal to obtain columnar particles having an average particle diameter D50 of 10 μm or more and 200 μm or less, and an aspect ratio of 0.05 or more and 0.6 or less as determined by SEM image analysis. It is characterized by having a process.
　本実施の形態では、燃焼合成法により、β窒化ケイ素合成体結晶（一次粒子）を合成するが、このとき、β窒化ケイ素は柱状成長し、図１Ａ、図１Ｂに示すように、複数の柱状粒子が凝集した構造とされる。ちなみに、ＡｌＮ結晶は、燃焼合成法にて等軸成長であり、柱状成長しない。 In this embodiment, β-silicon nitride composite crystals (primary particles) are synthesized by a combustion synthesis method. At this time, β-silicon nitride grows in a columnar shape, and as shown in FIGS. 1A and 1B, a plurality of columnar It is said to have a structure in which particles are aggregated. Incidentally, the AlN crystal grows equiaxed by the combustion synthesis method and does not grow columnar.
　上記（１）の工程では、原料に使用するＳｉの平均粒子径Ｄ５０は、例えば、２～１０μｍの範囲内である。これにより、酸素不純物量を抑制できるとともに燃焼速度を上昇させて合成温度を高くでき、良好な結晶成長を得ることができる。一例であるが、Ｓｉの平均粒子径Ｄ５０は、５μｍである。 In the step (1) above, the average particle diameter D50 of Si used as the raw material is, for example, within the range of 2 to 10 μm. This makes it possible to suppress the amount of oxygen impurities, increase the combustion rate, increase the synthesis temperature, and obtain good crystal growth. As an example, the average particle diameter D50 of Si is 5 μm.
　希釈剤として、窒化ケイ素粉末を使用する。該窒化ケイ素粉末は、α型であってもβ型であってもどちらでもよい。また、該窒化ケイ素粉末の平均粒子径Ｄ５０は、０．１～５μｍの範囲であることが好ましい。一例であるが、窒化ケイ素粉末の平均粒子径Ｄ５０は、１μｍである。希釈剤は、原料中に占めるＳｉ量を調整するために使用される。希釈剤の添加量は、原料中１０質量％～５０質量％の範囲内であることが好ましい。これにより、Ｓｉの溶着を抑制し燃焼を適切に生じさせるとともに、十分な熱量により優れた結晶成長を得ることができる。一例であるが、希釈剤は、原料中に２０質量％添加される。 Use silicon nitride powder as a diluent. The silicon nitride powder may be either α type or β type. Further, the average particle diameter D50 of the silicon nitride powder is preferably in the range of 0.1 to 5 μm. As an example, the average particle diameter D50 of silicon nitride powder is 1 μm. The diluent is used to adjust the amount of Si in the raw material. The amount of diluent added is preferably within the range of 10% by mass to 50% by mass in the raw material. Thereby, welding of Si can be suppressed and combustion can be appropriately caused, and excellent crystal growth can be obtained with a sufficient amount of heat. As an example, the diluent is added to the raw material in an amount of 20% by mass.
　本実施の形態では、原料中に希釈剤を混合し、断熱性耐熱容器に充填する。この断熱性耐熱容器は熱伝導率が１Ｗ/ｍＫ以下であり、材質はアルミナやジルコニアでも可能だが不純物の混入を考慮して炭素が好ましい。また、原料充填後に断熱性耐熱容器と同様の材質の物で蓋をする。さらに、燃焼時の合成体内部の温度を高くするため、混合原料の厚みは５０ｍｍ以上、好ましくは１００ｍｍ以上とする。なお、４００ｍｍ以上では冷却に時間がかかり製造コストがかかるため、４００ｍｍ以下であることが好ましい。そして、０．５～１ＭＰａ（例えば、０．９ＭＰａ）の範囲の窒素雰囲気下で燃焼合成を行う。圧力範囲を上記範囲内に調整することで、効率的な合成とともに設備コストの上昇を抑制できる。 In this embodiment, a diluent is mixed into the raw materials, and the mixture is filled into an insulating heat-resistant container. This heat-insulating heat-resistant container has a thermal conductivity of 1 W/mK or less, and the material can be alumina or zirconia, but carbon is preferable in consideration of contamination with impurities. In addition, after filling the raw materials, cover the container with a material similar to that of the heat-insulating heat-resistant container. Furthermore, in order to increase the temperature inside the composite during combustion, the thickness of the mixed raw material is set to 50 mm or more, preferably 100 mm or more. Note that if it is 400 mm or more, it will take time to cool down and increase manufacturing cost, so it is preferably 400 mm or less. Then, combustion synthesis is performed under a nitrogen atmosphere in the range of 0.5 to 1 MPa (for example, 0.9 MPa). By adjusting the pressure range within the above range, efficient synthesis can be achieved and an increase in equipment costs can be suppressed.
　結晶成長をより効果的に促進させるために、触媒を使用してもよい。例えば、Ｙ２Ｏ３、Ｆｅ２Ｏ３、ＣａＯ、Ｎｉ、Ｃｏ、Ｃ等を、０．０１～０．１質量％程度添加する。また、５００℃～１７００℃範囲（例えば、１５００℃）の外部補助加熱を行い、自己発火による燃焼合成法でも燃焼温度が高くなるため同様の柱状晶を得ることができる。 A catalyst may be used to more effectively promote crystal growth. For example, Y 2 O 3 , Fe 2 O 3 , CaO, Ni, Co, C, etc. are added in an amount of about 0.01 to 0.1% by mass. In addition, similar columnar crystals can be obtained by a combustion synthesis method using self-ignition by performing external auxiliary heating in the range of 500° C. to 1700° C. (for example, 1500° C.) because the combustion temperature becomes higher.
　図１Ａ、図１Ｂに示すように、β窒化ケイ素合成体結晶は、複数の柱状粒子が凝集した形態であるため、上記（２）の工程では、β窒化ケイ素合成体結晶を解砕し分級する。解砕工程では、例えば、合成体を、ハンマーミルやディスクミル等の一般的な粗粉砕装置で、目開き１５０μｍの篩を通過するまで解砕する。その後、２５μｍスリットのウェッジワイヤーを通して柱状晶を回収する。さらに、回収した柱状粒子を目開き２５μｍの篩に通し、混入している２５μｍ以下の凝集紛を除去する。 As shown in FIGS. 1A and 1B, the β-silicon nitride composite crystal is in the form of agglomerated columnar particles, so in the step (2) above, the β-silicon nitride composite crystal is crushed and classified. . In the crushing step, for example, the composite is crushed using a general coarse crushing device such as a hammer mill or a disc mill until it passes through a sieve with an opening of 150 μm. Thereafter, the columnar crystals are collected through a wedge wire with a 25 μm slit. Furthermore, the collected columnar particles are passed through a sieve with an opening of 25 μm to remove any agglomerated powder with a diameter of 25 μm or less.
　これにより、図２Ａ、図２Ｂに示すように、平均粒子径Ｄ５０が、１０μｍ以上２００μｍ以下であり、ＳＥＭ画像解析によるアスペクト比が、０．０５以上０．６以下であるβ窒化ケイ素柱状粒子を得ることができる。 As a result, as shown in FIGS. 2A and 2B, β silicon nitride columnar particles having an average particle diameter D50 of 10 μm or more and 200 μm or less and an aspect ratio of 0.05 or more and 0.6 or less as determined by SEM image analysis are obtained. Obtainable.
　このように、本実施の形態のβ窒化ケイ素柱状粒子の製造方法では、燃焼合成法の生成熱を利用してβ窒化ケイ素合成体結晶を合成し、これを解砕し分級するといった簡単な工程を経て、従来に比べて平均粒子径Ｄ５０が大きいβ窒化ケイ素柱状粒子を得ることができる。このため、熱伝導率が高く充填性に優れたβ窒化ケイ素柱状粒子を生産性良く製造できる。また燃焼合成法により省エネルギーで生産でき生産コストを低減できる。 As described above, the method for producing β-silicon nitride columnar particles of the present embodiment involves simple steps such as synthesizing β-silicon nitride composite crystals using the heat of formation in the combustion synthesis method, and crushing and classifying the crystals. Through this process, β silicon nitride columnar particles having a larger average particle diameter D50 than conventional ones can be obtained. Therefore, β-silicon nitride columnar particles with high thermal conductivity and excellent filling properties can be manufactured with high productivity. In addition, the combustion synthesis method enables energy-saving production and reduces production costs.
　次に、本実施の形態の複合粒子の製造方法について説明する。上記（１）（２）の工程後、以下の工程を行う。
（３）　（２）の工程にて、β窒化ケイ素柱状粒子を抽出した後、未回収の凝集紛を粉砕して、β窒化ケイ素粉砕粒子を得る工程、
（４）　β窒化ケイ素柱状粒子とβ窒化ケイ素粉砕粒子とを混合して（混合比は、１：９～９：１）、平均粒子径Ｄ５０が、５μｍ以上１５０μｍ以下であり、ＳＥＭ画像解析によるアスペクト比が、０．４以上０．７以下である複合粒子を得る工程。 Next, a method for manufacturing composite particles according to this embodiment will be explained. After the steps (1) and (2) above, the following steps are performed.
(3) After extracting the β-silicon nitride columnar particles in step (2), pulverizing the unrecovered agglomerated powder to obtain pulverized β-silicon nitride particles;
(4) By mixing β-silicon nitride columnar particles and β-silicon nitride pulverized particles (mixing ratio: 1:9 to 9:1), the average particle diameter D50 is 5 μm or more and 150 μm or less, and the result is determined by SEM image analysis. A step of obtaining composite particles having an aspect ratio of 0.4 or more and 0.7 or less.
　上記（２）の工程で除去した凝集紛を、上記（３）の工程では、粉砕し、例えば、平均粒子径Ｄ５０が１０μｍ以下になるまで行う。粉砕方法を限定するものではなく、一般的な転動ボールミルや、遊星ボールミル、振動ボールミル、ジェットミル等を使用できる。なお、どの程度の平均粒子径Ｄ５０になるまで粉砕するかは用途などにより種々選択できる。ここで得られたβ窒化ケイ素粉砕粒子は、柱状晶以外の形状であり、例えば球状、多面体であり、粒子表面が非常に滑らかである。 The agglomerated powder removed in step (2) above is pulverized in step (3) above, for example, until the average particle diameter D50 becomes 10 μm or less. The pulverization method is not limited, and a general rolling ball mill, planetary ball mill, vibrating ball mill, jet mill, etc. can be used. Note that the average particle diameter D50 to be pulverized can be variously selected depending on the purpose and the like. The β silicon nitride pulverized particles obtained here have a shape other than columnar crystals, such as spherical or polyhedral, and have very smooth particle surfaces.
　上記（４）の工程では、本実施の形態では、上記（２）の工程で得たβ窒化ケイ素柱状粒子と、上記（３）で得たβ窒化ケイ素粉砕粒子とを混合する。このとき、β窒化ケイ素粉砕粒子はβ窒化ケイ素柱状粒子より小さく、β窒化ケイ素柱状粒子とβ窒化ケイ素柱状粒子の間に入り込むなどして充填率を高めることができる。また本実施の形態では、粒子同士が、面接触や点接触以外に面と線との接触も増えるため、熱パスが多くなり、熱伝導性に優れる。 In step (4) above, in this embodiment, the β silicon nitride columnar particles obtained in step (2) above and the ground β silicon nitride particles obtained in step (3) above are mixed. At this time, the β silicon nitride pulverized particles are smaller than the β silicon nitride columnar particles, and can be inserted between the β silicon nitride columnar particles and the β silicon nitride columnar particles to increase the filling rate. In addition, in this embodiment, particles have more surface-to-line contact than surface contact or point contact, which increases the number of heat paths and provides excellent thermal conductivity.
　なお、本実施の形態では、例えば、上記（２）の工程で得たβ窒化ケイ素柱状粒子と、上記（３）の工程で得たβ窒化ケイ素粉砕粒子を、５００℃～８００℃（例えば、６００℃）で大気雰囲気にて熱処理を行うことが好ましい。これは、酸化膜を粒子表面に付けて安定化させ、且つ親水性を持たせるためである。熱処理を行った２種類の粉末を水に入れ撹拌混合後、湿式分級を行う。湿式分級は篩分級や比重分級などがあり、サイクロン分級を行った。この混合作業で柱状粉の混入量を操作し、用途に合わせ特性を出すことが可能となる。例えば、放熱特性に配向性を求める場合は柱状粉の混入量を多くする。 In this embodiment, for example, the β silicon nitride columnar particles obtained in step (2) above and the crushed β silicon nitride particles obtained in step (3) above are heated at 500° C. to 800° C. (for example, It is preferable to perform the heat treatment at a temperature of 600° C. in an air atmosphere. This is because an oxide film is attached to the particle surface to stabilize it and make it hydrophilic. Two types of heat-treated powders are placed in water, stirred and mixed, and then subjected to wet classification. Wet classification includes sieve classification and specific gravity classification, and cyclone classification was used. Through this mixing process, it is possible to control the amount of columnar powder mixed in and create characteristics that suit the application. For example, if orientation is required for heat dissipation properties, the amount of columnar powder mixed is increased.
＜効果＞
　本実施の形態のβ窒化ケイ素柱状粒子は、平均粒子径Ｄ５０及びアスペクト比の調整により、優れた熱伝導性を有している。ＡｌＮと対比すると、β窒化ケイ素柱状粒子、あるいは複合粒子は、ＡｌＮよりも耐水性及び熱伝導性の面で優れている。また、β窒化ケイ素柱状粒子は、大結晶としてのβ窒化ケイ素合成体結晶の解砕により得ることができ、滑らかな平面を有するβ窒化ケイ素柱状粒子、さらには凝集紛の粉砕により得られたβ窒化ケイ素粉砕粒子も粒子形状が滑らかであり、これらを混合した複合粒子は、充填性に優れる。特に、複合粒子には、柱状晶も含まれているため、熱パス的にも有利に作用し、熱伝導性の向上を図ることができる。 <Effect>
The β silicon nitride columnar particles of this embodiment have excellent thermal conductivity by adjusting the average particle diameter D50 and aspect ratio. In contrast to AlN, β silicon nitride columnar particles or composite particles are superior to AlN in terms of water resistance and thermal conductivity. In addition, β silicon nitride columnar particles can be obtained by crushing β silicon nitride composite crystals as large crystals, β silicon nitride columnar particles having smooth planes, and β silicon nitride columnar particles obtained by crushing aggregated powder. The crushed silicon nitride particles also have a smooth particle shape, and composite particles made by mixing these particles have excellent filling properties. In particular, since the composite particles also contain columnar crystals, they have an advantageous effect on the heat path and can improve thermal conductivity.
　また、本実施の形態におけるβ窒化ケイ素柱状粒子あるいは複合粒子は、フィラーとしての用途のみならず、焼結基板向けの種結晶や樹脂補強材として用いることもできる。 Further, the β silicon nitride columnar particles or composite particles in this embodiment can be used not only as a filler but also as a seed crystal or a resin reinforcing material for a sintered substrate.
　以下、本発明の効果を明確にするために実施した実施例により、本発明を詳細に説明する。なお、本発明は、以下の実施例によって何ら限定されるものではない。 Hereinafter, the present invention will be explained in detail with reference to Examples carried out to clarify the effects of the present invention. Note that the present invention is not limited in any way by the following examples.
＜β窒化ケイ素柱状粒子の実験＞
　実施例では、Ｓｉ粉末（粒子径＝５μｍ）に、希釈剤としての窒化ケイ素粉末（粒子径＝１μｍ）を希釈率２０質量％として転動ボールミルで混合し、炭素質の断熱性耐熱容器に原料層厚１００ｍｍになるように充填した後、炭素質の断熱性耐熱材からなる蓋をし、０．５ＭＰａの窒素雰囲気下で合成を行った。合成後は、ハンマークラッシャーにて、目開き１５０μｍの篩を通過するまで粗粉砕を行い（解砕）、さらに、２５μｍスリットのウェッジワイヤ―を通して、平均粒子径Ｄ５０＝５３μｍのβ窒化ケイ素柱状粒子を回収した。Ｄ５０は、レーザ回折粒度分布測定装置（ＨＯＲＩＢＡ製　ＬＡ－９５０）にて測定した。また、Ｄ１０及びＤ９０も測定した。さらに、ＳＥＭ（Ｐｈｅｎｏｍ　Ｐｒｏｘ）により観察を行い、解析ソフト（Ｐａｒｔｉｃｌｅ　Ｍｅｔｒｉｃ）にて、４００個の粒子のアスペクト比（短径／長径）を測定し、その平均値で求めた。 <Experiment on beta silicon nitride columnar particles>
In the example, Si powder (particle size = 5 μm) and silicon nitride powder (particle size = 1 μm) as a diluent were mixed in a rolling ball mill at a dilution rate of 20% by mass, and the raw materials were placed in a carbonaceous heat-insulating heat-resistant container. After filling to a layer thickness of 100 mm, a lid made of a carbonaceous heat-insulating heat-resistant material was placed, and synthesis was performed under a nitrogen atmosphere of 0.5 MPa. After synthesis, coarsely pulverize (crush) with a hammer crusher until it passes through a sieve with an opening of 150 μm, and then pass through a wedge wire with a 25 μm slit to obtain β silicon nitride columnar particles with an average particle size D50 = 53 μm. Recovered. D50 was measured using a laser diffraction particle size distribution analyzer (LA-950 manufactured by HORIBA). In addition, D10 and D90 were also measured. Further, observation was performed using SEM (Phenom Prox), and the aspect ratio (breadth axis/long axis) of 400 particles was measured using analysis software (Particle Metric), and the average value was determined.
　上記における柱状粒子の合成及び測定を３回行い、各回で得た柱状粒子を、それぞれ、柱状粒子１、柱状粒子２、柱状粒子３とした。その実験結果が表１に示されている。 The above synthesis and measurement of columnar particles was performed three times, and the columnar particles obtained each time were designated as columnar particles 1, columnar particles 2, and columnar particles 3, respectively. The experimental results are shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、柱状粒子のＤ５０は、１０μｍ～２００μｍの範囲内であり、２０μｍ～１００μｍの範囲内であることが好ましいとわかった。また、アスペクト比は、０．０５～０．６の範囲内であり、０．１～０．５の範囲内であることが好ましいとわかった。 As shown in Table 1, the D50 of the columnar particles was found to be within the range of 10 μm to 200 μm, preferably within the range of 20 μm to 100 μm. Further, it has been found that the aspect ratio is within the range of 0.05 to 0.6, preferably within the range of 0.1 to 0.5.
＜複合粒子の実験＞
　続いて、β窒化ケイ素柱状粒子を抽出後、未回収の凝集紛をボールミルで粉砕してβ窒化ケイ素粉砕粒子を得て、β窒化ケイ素柱状粒子とβ窒化ケイ素粉砕粒子を混合した後、湿式分級にて平均粒子径Ｄ５０＝５μｍ、１０μｍ、２０μｍの複合粒子を得た。β窒化ケイ素柱状粒子とβ窒化ケイ素粉砕粒子との混合比を、２：８とした。実験では、β窒化ケイ素柱状粒子とβ窒化ケイ素粉砕粒子とを、シリコーンオイル（信越化学工業社製　ＫＦ－９６－２０ＣＳ）に混合した。 <Experiment on composite particles>
Subsequently, after extracting the β silicon nitride columnar particles, the unrecovered agglomerated powder is ground in a ball mill to obtain the β silicon nitride pulverized particles. After mixing the β silicon nitride columnar particles and the β silicon nitride pulverized particles, wet classification is performed. Composite particles having average particle diameters D50 of 5 μm, 10 μm, and 20 μm were obtained. The mixing ratio of the β silicon nitride columnar particles and the β silicon nitride pulverized particles was 2:8. In the experiment, β silicon nitride columnar particles and β silicon nitride pulverized particles were mixed in silicone oil (KF-96-20CS, manufactured by Shin-Etsu Chemical Co., Ltd.).
　実施例１は、平均粒子径Ｄ５０＝５μｍとし、実施例２は、平均粒子径Ｄ５０＝１０μｍとし、実施例３は、平均粒子径Ｄ５０＝２０μｍとした。なお図３Ａ、図３Ｂは、実施例３のＳＥＭ写真及び部分模式図である。そして、各実施例のアスペクト比及び熱伝導率を測定した。「熱伝導率」は、温度波測定法（ａｉ－Ｐｈａｓｅ）で測定した。 Example 1 had an average particle diameter D50 of 5 μm, Example 2 had an average particle diameter D50 of 10 μm, and Example 3 had an average particle diameter D50 of 20 μm. Note that FIGS. 3A and 3B are a SEM photograph and a partial schematic diagram of Example 3. Then, the aspect ratio and thermal conductivity of each example were measured. "Thermal conductivity" was measured by temperature wave measurement method (ai-Phase).
　さらに、比較例１～６を用意した。比較例１～３は、通常合成によるβ窒化ケイ素粒子の粗粒分級品であり、比較例１は、平均粒子径Ｄ５０＝５μｍとし、比較例２は、平均粒子径Ｄ５０＝１０μｍとし、比較例３は、平均粒子径Ｄ５０＝２０μｍとした。図４Ａ、図４Ｂは、比較例３のＳＥＭ写真及び部分模式図である。なお、「通常合成」とは、結晶成長を意図していない合成方法であり、カーボン製の非断熱性坩堝を用い、希釈率を５０ｗｔ％、ガス圧を７００ＫＰａ、原料サイズは実施例と同じとし、原料層厚は４０ｍｍであった。 Additionally, Comparative Examples 1 to 6 were prepared. Comparative Examples 1 to 3 are coarsely classified β silicon nitride particles obtained by conventional synthesis, Comparative Example 1 has an average particle diameter D50 of 5 μm, Comparative Example 2 has an average particle diameter D50 of 10 μm, and In No. 3, the average particle diameter D50 was 20 μm. 4A and 4B are a SEM photograph and a partial schematic diagram of Comparative Example 3. Note that "normal synthesis" is a synthesis method that does not intend crystal growth, and uses a non-insulated crucible made of carbon, the dilution rate is 50 wt%, the gas pressure is 700 KPa, and the raw material size is the same as in the example. , the raw material layer thickness was 40 mm.
　また、比較例４～比較例６は、ＡｌＮ粒子であり、比較例４は、平均粒子径Ｄ５０が５μｍのＡｌＮフィラー（（株）燃焼合成製　ＡＮ－ＨＦ０５ＬＧ－ＨＴＺ）、比較例５は、平均粒子径Ｄ５０が１０μｍのＡｌＮフィラー（（株）燃焼合成製　ＡＮ－ＨＦ１０ＬＧ－ＨＴＺ）、比較例６は、平均粒子径Ｄ５０が２０μｍのＡｌＮフィラー（（株）燃焼合成製　ＡＮ－ＨＦ２０ＬＧ－ＨＴＺ）であった。その実験結果が以下の表２に示されている。 In addition, Comparative Examples 4 to 6 are AlN particles, Comparative Example 4 is an AlN filler with an average particle diameter D50 of 5 μm (AN-HF05LG-HTZ manufactured by Kabuki Gosei Co., Ltd.), and Comparative Example 5 is an AlN filler with an average particle diameter D50 of 5 μm. Comparative Example 6 was an AlN filler with a particle diameter D50 of 10 μm (AN-HF10LG-HTZ, manufactured by Yasushi Gosei Co., Ltd.), and Comparative Example 6 was an AlN filler (AN-HF20LG-HTZ, manufactured by Yasushi Gosei Co., Ltd.) with an average particle diameter D50 of 20 μm. there were. The experimental results are shown in Table 2 below.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２に示すように、実施例１～３は、比較例１～６と同じＤ５０と比較するといずれも高い熱伝導率を得ることができた。また、実施例１～３は、比較例１～６よりもアスペクト比が小さくなっており、実施例１～３が、β窒化ケイ素柱状粒子とβ窒化ケイ素粉砕粒子の複合粒子としての特長も確認できた。 As shown in Table 2, Examples 1 to 3 were all able to obtain high thermal conductivity when compared with the same D50 as Comparative Examples 1 to 6. In addition, Examples 1 to 3 have smaller aspect ratios than Comparative Examples 1 to 6, confirming the characteristics of Examples 1 to 3 as composite particles of β silicon nitride columnar particles and β silicon nitride pulverized particles. did it.
＜充填性に関する実験＞
　次に、表２に示す実施例３と比較例３を用い、充填量と粘度との関係を調べた。その実験結果が表３に示されている。 <Experiments on filling properties>
Next, using Example 3 and Comparative Example 3 shown in Table 2, the relationship between filling amount and viscosity was investigated. The experimental results are shown in Table 3.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表３に示すように粒子の充填率を４６体積％～５８体積％まで変え、各充填率の際の粘度（２５℃）を測定した。また、粘度は、Ｂ型粘度計を用いて２５℃の粘度を測定した。なお、タップ密度を測定すると、実施例では１．００～１．４０（ｇ／ｃｃ）程度であった。 As shown in Table 3, the filling rate of the particles was varied from 46% by volume to 58% by volume, and the viscosity (25°C) at each filling rate was measured. Further, the viscosity was measured at 25° C. using a B-type viscometer. Note that when the tap density was measured, it was about 1.00 to 1.40 (g/cc) in the examples.
　表３に示すように、比較例３では、充填率が５２体積％で充填限界に達したが、実施例３では、５８体積％が充填限界となり、実施例３のほうが比較例３に比べて充填性に優れることがわかった。実施例３では、β窒化ケイ素柱状粒子及びβ窒化ケイ素粉砕粒子がいずれも滑らかな平面（表面の８０％以上を占めることを確認した）を具備した結果、充填性に優れ、また、柱状粒子も含むことで、表２より、熱パス的にも有利に作用し、熱伝導性が向上したことを確認できた。 As shown in Table 3, in Comparative Example 3, the filling rate reached the filling limit at 52% by volume, but in Example 3, the filling limit reached 58% by volume, and Example 3 was better than Comparative Example 3. It was found that the filling properties were excellent. In Example 3, both the β-silicon nitride columnar particles and the β-silicon nitride crushed particles had smooth flat surfaces (it was confirmed that they occupied more than 80% of the surface), and as a result, the filling properties were excellent, and the columnar particles also From Table 2, it was confirmed that the inclusion of the compound had an advantageous effect on the heat path and improved thermal conductivity.
　本発明のβ窒化ケイ素柱状粒子は、優れた耐水性及び熱伝導性を有し、また安価に製造することが可能であり、放熱フィラーのみならず、焼結基板向けの種結晶にも効果的に利用することができる。 The β silicon nitride columnar particles of the present invention have excellent water resistance and thermal conductivity, can be manufactured at low cost, and are effective not only as heat dissipation fillers but also as seed crystals for sintered substrates. It can be used for.
　本出願は、２０２２年４月２７日出願の特願２０２２－０７３０１５に基づく。この内容は全てここに含めておく。
  This application is based on Japanese Patent Application No. 2022-073015 filed on April 27, 2022. All of this content will be included here.

Claims (8)

  1. 　平均粒子径Ｄ５０が、１０μｍ以上２００μｍ以下の柱状粒子であり、
    　ＳＥＭ画像解析によるアスペクト比が、０．０５以上０．６以下である、
    　ことを特徴とするβ窒化ケイ素柱状粒子。     Columnar particles having an average particle diameter D50 of 10 μm or more and 200 μm or less,
    The aspect ratio according to SEM image analysis is 0.05 or more and 0.6 or less,
    β silicon nitride columnar particles characterized by:
  2. 　前記平均粒子径Ｄ５０が、２５μｍ以上１００μｍ以下である、ことを特徴とする請求項１に記載のβ窒化ケイ素柱状粒子。 The beta silicon nitride columnar particles according to claim 1, wherein the average particle diameter D50 is 25 μm or more and 100 μm or less.
  3. 　請求項１に記載のβ窒化ケイ素柱状粒子と、β窒化ケイ素粉砕粒子とを含み、
    　平均粒子径Ｄ５０が、５μｍ以上１５０μｍ以下であり、
    　ＳＥＭ画像解析によるアスペクト比が、０．４以上０．７以下である、
    　ことを特徴とする複合粒子。     comprising the β silicon nitride columnar particles according to claim 1 and the β silicon nitride pulverized particles,
    The average particle diameter D50 is 5 μm or more and 150 μm or less,
    The aspect ratio according to SEM image analysis is 0.4 or more and 0.7 or less,
    Composite particles characterized by:
  4. 　請求項１に記載のβ窒化ケイ素柱状粒子、あるいは、請求項３に記載の複合粒子を焼成してなる、ことを特徴とする放熱用焼結基板。 A sintered substrate for heat dissipation, characterized in that it is formed by firing the β silicon nitride columnar particles according to claim 1 or the composite particles according to claim 3.
  5. 　請求項１に記載のβ窒化ケイ素柱状粒子、あるいは、請求項３に記載の複合粒子を含む、ことを特徴とする樹脂複合物。 A resin composite comprising the β silicon nitride columnar particles according to claim 1 or the composite particles according to claim 3.
  6. 　請求項１に記載のβ窒化ケイ素柱状粒子、あるいは、請求項３に記載の複合粒子を含む、ことを特徴とする無機複合物。 An inorganic composite comprising the β silicon nitride columnar particles according to claim 1 or the composite particles according to claim 3.
  7. 　Ｓｉを含む原料を用いて、窒素雰囲気下にて燃焼合成法により、β窒化ケイ素合成体結晶を合成し、
    　前記β窒化ケイ素合成体結晶を解砕・分級して、平均粒子径Ｄ５０が、１０μｍ以上２００μｍ以下であり、ＳＥＭ画像解析によるアスペクト比が、０．０５以上０．６以下である柱状粒子を得る、
    　ことを特徴とするβ窒化ケイ素柱状粒子の製造方法。     Synthesizing β-silicon nitride composite crystals by a combustion synthesis method in a nitrogen atmosphere using raw materials containing Si,
    The β-silicon nitride composite crystals are crushed and classified to obtain columnar particles having an average particle diameter D50 of 10 μm or more and 200 μm or less, and an aspect ratio of 0.05 or more and 0.6 or less as determined by SEM image analysis. ,
    A method for producing β-silicon nitride columnar particles, characterized by:
  8. 　請求項７に記載のβ窒化ケイ素柱状粒子を抽出した後の凝集紛を粉砕して、β窒化ケイ素粉砕粒子を得た後、
    　前記β窒化ケイ素柱状粒子と前記β窒化ケイ素粉砕粒子とを混合して、
    　平均粒子径Ｄ５０が、５μｍ以上１５０μｍ以下であり、
    　ＳＥＭ画像解析によるアスペクト比が、０．４以上０．７以下である複合粒子を得る、
    　ことを特徴とする複合粒子の製造方法。

          After pulverizing the agglomerated powder after extracting the β-silicon nitride columnar particles according to claim 7 to obtain pulverized β-silicon nitride particles,
    Mixing the β silicon nitride columnar particles and the β silicon nitride pulverized particles,
    The average particle diameter D50 is 5 μm or more and 150 μm or less,
    Obtaining composite particles having an aspect ratio of 0.4 or more and 0.7 or less as determined by SEM image analysis.
    A method for producing composite particles characterized by:
PCT/JP2023/016330 2022-04-27 2023-04-25 COLUMNAR PARTICLES OF β-SILICON NITRIDE, COMPOSITE PARTICLES, SINTERED SUBSTRATE FOR HEAT RADIATION, RESIN COMPOSITE, INORGANIC COMPOSITE, METHOD FOR PRODUCING COLUMNAR PARTICLES OF β-SILICON NITRIDE, AND METHOD FOR PRODUCING COMPOSITE PARTICLES WO2023210649A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022073015 2022-04-27
JP2022-073015 2022-04-27

Publications (1)

Publication Number Publication Date
WO2023210649A1 true WO2023210649A1 (en) 2023-11-02

Family

ID=88519037

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2023/016330 WO2023210649A1 (en) 2022-04-27 2023-04-25 COLUMNAR PARTICLES OF β-SILICON NITRIDE, COMPOSITE PARTICLES, SINTERED SUBSTRATE FOR HEAT RADIATION, RESIN COMPOSITE, INORGANIC COMPOSITE, METHOD FOR PRODUCING COLUMNAR PARTICLES OF β-SILICON NITRIDE, AND METHOD FOR PRODUCING COMPOSITE PARTICLES

Country Status (1)

Country Link
WO (1) WO2023210649A1 (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01182331A (en) * 1988-01-14 1989-07-20 Denki Kagaku Kogyo Kk Filler
JPH0664906A (en) * 1992-08-21 1994-03-08 Denki Kagaku Kogyo Kk Powdery silicon nitride
JPH11268903A (en) * 1998-03-24 1999-10-05 Denki Kagaku Kogyo Kk Silicon nitride-based filler and resin composition for sealing semiconductor
CN101857441A (en) * 2010-06-25 2010-10-13 清华大学 Method for preparing beta-silicon nitride powder
WO2018110565A1 (en) * 2016-12-12 2018-06-21 宇部興産株式会社 Method for producing high-purity silicon nitride powder
WO2018110560A1 (en) * 2016-12-12 2018-06-21 宇部興産株式会社 Silicon nitride powder, release agent for polycrystalline silicon ingot, and method for producing polycrystalline silicon ingot

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01182331A (en) * 1988-01-14 1989-07-20 Denki Kagaku Kogyo Kk Filler
JPH0664906A (en) * 1992-08-21 1994-03-08 Denki Kagaku Kogyo Kk Powdery silicon nitride
JPH11268903A (en) * 1998-03-24 1999-10-05 Denki Kagaku Kogyo Kk Silicon nitride-based filler and resin composition for sealing semiconductor
CN101857441A (en) * 2010-06-25 2010-10-13 清华大学 Method for preparing beta-silicon nitride powder
WO2018110565A1 (en) * 2016-12-12 2018-06-21 宇部興産株式会社 Method for producing high-purity silicon nitride powder
WO2018110560A1 (en) * 2016-12-12 2018-06-21 宇部興産株式会社 Silicon nitride powder, release agent for polycrystalline silicon ingot, and method for producing polycrystalline silicon ingot

Similar Documents

Publication Publication Date Title
JP4750220B2 (en) Hexagonal boron nitride powder and method for producing the same
CN111212811B (en) Boron nitride powder, method for producing same, and heat-dissipating member using same
TW201827383A (en) Boron nitride aggregated grain, method for producing same, and thermally conductive resin composition using same
JP5689985B2 (en) BN Sintered Particles with Recesses, Method for Producing the Same, and Polymer Material
JPWO2020004600A1 (en) Bulked boron nitride particles, boron nitride powder, method for producing boron nitride powder, resin composition, and heat radiating member
JP2016135731A (en) Boron nitride aggregated particle, method for producing boron nitride aggregated particle, resin composition containing boron nitride aggregated particle, and molding
JP6245602B2 (en) Silicon nitride filler, resin composite, insulating substrate, semiconductor encapsulant, method for producing silicon nitride filler
JP2021165228A (en) Aluminum nitride-boron nitride composite agglomerated particle and method for producing the same
JP2007308360A (en) Hexagonal boron nitride powder
JP6500339B2 (en) Heat dissipation sheet, coating liquid for heat dissipation sheet, and power device
CN107663092B (en) Preparation method of AlN powder
WO2023210649A1 (en) COLUMNAR PARTICLES OF β-SILICON NITRIDE, COMPOSITE PARTICLES, SINTERED SUBSTRATE FOR HEAT RADIATION, RESIN COMPOSITE, INORGANIC COMPOSITE, METHOD FOR PRODUCING COLUMNAR PARTICLES OF β-SILICON NITRIDE, AND METHOD FOR PRODUCING COMPOSITE PARTICLES
KR100428948B1 (en) A production method of tungsten nano powder without impurities and its sintered part
JPH083601A (en) Aluminum-aluminum nitride composite material and its production
JP2023098213A (en) calcium titanate powder
WO2023127742A1 (en) Boron nitride particles and heat dissipation sheet
JP4958353B2 (en) Aluminum nitride powder and method for producing the same
JP4203593B2 (en) Method for producing spherical aluminum nitride filler
TWI788146B (en) Preparation method of aluminum nitride fine powder
WO2024048663A1 (en) Aluminum nitride powder and resin composition
WO2023127729A1 (en) Boron nitride particles and heat dissipation sheet
US20230312353A1 (en) Silicon carbide powder and manufacturing method for same
KR102509020B1 (en) SiC Powder For Pressureless Sintering From Wasted Solar Panel And Manufacturing Metholds Thereof
TWI838500B (en) Blocky boron nitride particles, heat conductive resin composition, and heat dissipation member
JPH09183660A (en) High fillability hexagonal boron nitride powder, its production and use thereof

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23796389

Country of ref document: EP

Kind code of ref document: A1