WO2014156866A1 - Corps poreux en nitrure de silicium, procédé de production d'un corps poreux en nitrure de silicium, structure en nid d'abeille et filtre en nid d'abeille - Google Patents

Corps poreux en nitrure de silicium, procédé de production d'un corps poreux en nitrure de silicium, structure en nid d'abeille et filtre en nid d'abeille Download PDF

Info

Publication number
WO2014156866A1
WO2014156866A1 PCT/JP2014/057493 JP2014057493W WO2014156866A1 WO 2014156866 A1 WO2014156866 A1 WO 2014156866A1 JP 2014057493 W JP2014057493 W JP 2014057493W WO 2014156866 A1 WO2014156866 A1 WO 2014156866A1
Authority
WO
WIPO (PCT)
Prior art keywords
silicon nitride
particles
silicon
porous body
degreasing
Prior art date
Application number
PCT/JP2014/057493
Other languages
English (en)
Japanese (ja)
Inventor
山口　宏
宏昭 岡野
理沙 片山
Original Assignee
株式会社クボタ
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 株式会社クボタ filed Critical 株式会社クボタ
Publication of WO2014156866A1 publication Critical patent/WO2014156866A1/fr

Links

Images

Classifications

    • 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
    • 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
    • C04B35/591—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 obtained by reaction sintering
    • 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
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
    • C04B35/638—Removal thereof
    • 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
    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/0006—Honeycomb structures
    • 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
    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/06—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by burning-out added substances by burning natural expanding materials or by sublimating or melting out added substances
    • C04B38/0615—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by burning-out added substances by burning natural expanding materials or by sublimating or melting out added substances the burned-out substance being a monolitic element having approximately the same dimensions as the final article, e.g. a porous polyurethane sheet or a prepreg obtained by bonding together resin particles
    • 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
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00793—Uses not provided for elsewhere in C04B2111/00 as filters or diaphragms
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3217—Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
    • C04B2235/3222—Aluminates other than alumino-silicates, e.g. spinel (MgAl2O4)
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/38—Non-oxide ceramic constituents or additives
    • C04B2235/3817—Carbides
    • C04B2235/3826—Silicon carbides
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/42—Non metallic elements added as constituents or additives, e.g. sulfur, phosphor, selenium or tellurium
    • C04B2235/428—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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/48—Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/60—Aspects relating to the preparation, properties or mechanical treatment of green bodies or pre-forms
    • C04B2235/602—Making the green bodies or pre-forms by moulding
    • C04B2235/6021—Extrusion moulding
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/658—Atmosphere during thermal treatment
    • C04B2235/6583—Oxygen containing atmosphere, e.g. with changing oxygen pressures
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/66—Specific sintering techniques, e.g. centrifugal sintering
    • C04B2235/661—Multi-step sintering
    • C04B2235/662—Annealing after sintering
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/74—Physical characteristics
    • C04B2235/77—Density
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/80—Phases present in the sintered or melt-cast ceramic products other than the main phase
    • 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
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/80—Phases present in the sintered or melt-cast ceramic products other than the main phase
    • C04B2235/85—Intergranular or grain boundary phases

Definitions

  • the present invention relates to a silicon nitride-based porous body used for exhaust gas treatment, a manufacturing method thereof, a honeycomb structure using the same, and a honeycomb filter.
  • Ceramic porous bodies are used in exhaust gas treatment members of internal combustion engines.
  • it is used as a DPF (Diesel Particulate Filter) for collecting and purifying particulate matter contained in exhaust gas.
  • DPF Diesel Particulate Filter
  • As such a porous material cordierite, aluminum titanate, silicon carbide, etc. have already been put into practical use from the viewpoint of heat resistance and thermal shock resistance of the material, and silicon nitride (Si 3 N 4 ) has also been put into practical use. It is being considered.
  • Such a ceramic porous body is first made into a clay that can be extruded by adding a binder material (such as methylcellulose or an organic binder resin) to an inorganic raw material.
  • a binder material such as methylcellulose or an organic binder resin
  • a pore-forming material for adjusting the amount of pores is also added to the clay.
  • the formed clay is extruded to obtain a desired shape, which is dried, degreased and sintered.
  • Degreasing is a process of removing organic components such as a binder substance
  • sintering is a process of baking and solidifying an inorganic raw material.
  • the degreasing step it is generally performed that the degreasing is not completed but all the organic components are removed and a little is left. This is because if the organic component is completely removed, the substance that binds the inorganic raw materials disappears, and the molded product collapses before sintering.
  • Patent Document 1 discloses that silicon carbide (SiC) is formed at the manufacturing stage in a silicon nitride-based porous body manufactured by heat-treating raw materials composed of silicon oxide particles, carbon particles, and metal silicon particles in a nitrogen atmosphere. It is described that it is contained in a porous body. According to Patent Document 1, it is described that silicon carbide is not preferable in the silicon nitride based porous body.
  • Japanese Patent Publication Japanese Patent Laid-Open No. 2001-206775 (published July 31, 2001)”
  • an oxide film (SiO 2 ) on the surface of the silicon nitride particles reacts with magnesia spinel or the like added to the raw material as an auxiliary agent to form glass. Acts as an adhesive to bond the silicon nitride particles together. Therefore, when the oxide film on the surface of the silicon nitride particles changes from SiO 2 to SiO by reacting with the remaining carbon, it does not react with the auxiliary agent, and the amount of glass formed is insufficient. As a result, the bonding between the silicon nitride particles becomes brittle, and the mechanical strength of the porous body is reduced.
  • Patent Document 1 does not use silicon nitride particles as a raw material, and does not describe any of the above problems.
  • an object of the present invention is to provide a silicon nitride-based porous body having excellent mechanical strength and high thermal conductivity, a method for manufacturing the same, a honeycomb structure, and a honeycomb filter.
  • the inventors of the present application focused on effective use of organic substances that must be left in the degreasing process, and conducted intensive studies. As a result, in the state of silicon carbide, which has conventionally been considered unfavorable to be included in the silicon nitride-based porous body, by making it exist within a predetermined amount range, The present inventors have found that it is excellent in mechanical strength and can be increased to thermal conductivity, and have come to carry out the present invention.
  • the silicon nitride based porous material of the present invention is a silicon nitride based porous material in which silicon nitride particles and silicon particles are used as raw materials, and the silicon nitride particles are bonded to each other by glass. It is characterized by being included in the range of 5-22 wt% and having a porosity of 40-70%.
  • carbon which is an organic component that must be left in the degreasing process, is reacted with the silicon particles of the raw material and included as silicon carbide in the silicon nitride-based porous body, so that the remaining organic component is silicon nitride. It does not occur that the amount of glass produced is insufficient due to reaction with SiO 2 which is an oxide film on the surface of the particles, and the mechanical strength of the porous body can be maintained.
  • the silicon carbide particles to be included are in the range of 5 to 22 wt%.
  • Silicon carbide is a substance having higher thermal conductivity than silicon nitride. Therefore, the thermal conductivity of the silicon nitride based porous body mainly composed of silicon nitride can be increased by containing silicon carbide particles.
  • the silicon nitride porous body is made of silicon nitride particles and the silicon nitride particles are bonded to each other by glass, and has excellent mechanical strength and high thermal conductivity while ensuring ease of manufacture. It is possible to obtain a silicon nitride-based porous body having
  • the method for producing a silicon nitride based porous material of the present invention is a method of producing glass by reacting raw material silicon nitride particles, silicon particles, and SiO 2 on the surface of the silicon nitride particles.
  • a mixing step of mixing a binder, an organic binder substance, and a pore former, a molding step of molding the mixture obtained in the mixing step, and a molding obtained in the molding step are mixed in an atmosphere.
  • the silicon While the particles are converted to silicon carbide particles with organic components contained after degreasing, the silicon particles are nitrided to form silicon nitride particles, and then the raw silicon nitride particles and the nitrided silicon nitride particles formed on the respective surfaces of SiO 2 and a sintering aid are reacted to produce glass, and the silicon nitride particles are bonded together by glass.
  • the remaining organic component reacts with the silicon particles in the sintering step.
  • silicon carbide particles are produced.
  • the remaining organic component does not react with SiO 2 that is the oxide film on the surface of the silicon nitride particles to cause a shortage of the amount of glass produced, and the mechanical strength of the porous body can be maintained.
  • the amount of glass produced can be secured, it has been confirmed that when the content of silicon carbide particles exceeds 22 wt%, the mechanical strength of the porous body decreases.
  • the content of the silicon carbide particles is less than 5 wt%, the molded product before sintering is easily collapsed and is difficult to manufacture. Therefore, in the degreasing step, the amount of oxygen to be mixed in the atmosphere is adjusted, and the amount of organic components remaining after degreasing reacts with silicon in the sintering step so that 5 to 22 wt% silicon carbide particles are generated. It is adjusted to. Silicon particles that have not reacted with carbon are nitrided into silicon nitride particles in the sintering process, mixed with the original silicon nitride particles, and bonded with glass.
  • Silicon carbide is a substance having higher thermal conductivity than silicon nitride. Therefore, the thermal conductivity of the silicon nitride based porous body mainly composed of silicon nitride can be increased by containing silicon carbide particles.
  • the present invention there is an effect that it is possible to provide a silicon nitride-based porous body having excellent mechanical strength and high thermal conductivity, a manufacturing method thereof, a honeycomb structure, and a honeycomb filter without hindering the ease of manufacturing. .
  • FIG. 1 is a perspective view showing an overview of a honeycomb filter according to an embodiment of the present invention. It is a schematic cross section of a plane parallel to the axial direction of the honeycomb filter.
  • the silicon nitride based porous body according to the present embodiment can be used, for example, as an exhaust gas processing member of an internal combustion engine. It can be used as an exhaust gas catalyst support for gasoline engines, as an oxidation catalyst support for exhaust gas treatment for diesel engines, or as a DPF (Diesel Particulate Filter) for collecting and purifying particulate matter contained in exhaust gas.
  • a DPF Diesel Particulate Filter
  • the silicon nitride based porous material according to the present embodiment is mainly composed of silicon nitride particles (Si 3 N 4 ), and the silicon nitride particles are bonded to each other by glass existing between them. Further, between silicon nitride particles, silicon carbide particles (SiC) are contained at 5 to 22 wt%, and Al, Mg, and the like as sintering aids that react with SiO 2 on the surface of the silicon nitride particles to produce glass. At least one of the group consisting of Fe, Zr, or rare earth may be included.
  • the silicon nitride based porous material also includes sialon in which a part of silicon and nitrogen of silicon nitride is replaced with aluminum and oxygen, respectively.
  • silicon (Si) particles are included in the raw material together with the silicon nitride particles, and the organic components remaining after the degreasing step are reacted with the silicon particles in the sintering step.
  • silicon carbide particles are produced.
  • the oxide film on the surface of silicon nitride particles (SiO 2) is reacted with sintering aids A sufficient amount of glass can be produced, and the silicon nitride particles can be firmly bonded to each other.
  • Silicon carbide is a substance having higher thermal conductivity than silicon nitride. Therefore, the thermal conductivity of the silicon nitride-based porous body mainly composed of silicon nitride can be increased by positively containing an organic component that must be left in the degreasing step in the form of silicon carbide.
  • the porosity is preferably 40 to 70%. By setting it as such a porosity, it can be functioned stably as DPF.
  • the porosity is in the above range because if the porosity is less than 40%, the performance of collecting the particulate matter cannot be guaranteed and the pressure loss becomes large. On the contrary, if the porosity exceeds 70%, it is used. This is because it is impossible to obtain a strength that can withstand the above.
  • the raw material silicon nitride particles particles having a particle diameter of 60 to 90 ⁇ m are used.
  • the reason why the particle diameter is in such a range is that when the particle diameter is less than 60 ⁇ m, the pressure loss increases, and conversely, when the particle diameter is greater than 90 ⁇ m, the collection performance decreases.
  • the raw material silicon particles those having the same particle size as the silicon nitride particles are used.
  • the silicon particles react with carbon to produce silicon carbide particles, but in the sintering process under a nitrogen atmosphere, the silicon particles also react with nitrogen to produce silicon nitride particles. Therefore, it is preferable that the particle diameter of the silicon particles is equal to that of the silicon nitride particles.
  • the amount of silicon particles is 10 to 50 wt% with respect to the total weight of silicon nitride particles + silicon particles.
  • the amount of silicon is within such a range is that when the amount is less than 10 wt%, the amount of the remaining organic component reacts with carbon and reacts with the oxide film (SiO 2 ) on the surface of the silicon nitride particles. Conversely, if it exceeds 50 wt%, low-speed sintering is required to avoid abnormal heat generation during nitriding in the sintering process, and productivity is reduced.
  • a combination of methylcellulose and water can be used as a binder material (organic binder material) for making the inorganic raw material a clay that can be extruded.
  • organic binder material organic binder material
  • the addition amount is 10 to 20 wt% with respect to the total weight of the silicon nitride particles, the silicon particles, and the pore former.
  • the reason why the amount of addition is in such a range is that when the amount of addition is less than 10 wt%, extrusion molding cannot be performed, and conversely, when it exceeds 20 wt%, it is difficult to degrease the next step.
  • a pore former is added to the raw material, and for example, starch can be used as the pore former.
  • the added amount of the pore former is 20 to 40 wt% with respect to the total weight of the silicon nitride particles, the silicon particles, and the pore former. By setting the addition amount in such a range, the porosity can be stably controlled.
  • the particle size of the pore former is preferably 70 to 100 ⁇ m, which is almost the same as the particle size of silicon.
  • Any sintering aid may be used as long as it generates glass by reacting with SiO 2 on the surface of the silicon nitride particles.
  • SiO 2 silicon nitride particles
  • Al, Mg, Fe, Zr, or rare earth can be used. At this time, some of the silicon nitride particles may be dissolved in the glass.
  • silicon nitride particles, silicon particles, a pore former and a sintering aid are mixed with a binder substance to obtain a mixture (mixing step).
  • extrusion is performed using an extrusion die, and the honeycomb structure or the like is molded into a desired shape (molding process), and then the molded product is dried.
  • the amount of oxygen mixed in the dried molding is adjusted in a nitrogen atmosphere, and the organic matter such as the binder substance and pore former remaining in the degreasing process reacts with the silicon particles in the sintering process. And degreasing so as to produce 5 to 22 wt% of silicon carbide (degreasing step).
  • degreasing step As a guideline of the amount of carbon remaining in the degreasing process, carbon that is an organic substance remaining in the sintering process reacts with silicon particles to produce 5 to 22 wt% silicon carbide particles. %.
  • degreasing is performed in a state where oxygen is added to a nitrogen atmosphere, and at that time, the amount of oxygen (O 2 ) added to nitrogen (N 2 ) is adjusted, whereby carbon that is an organic component to be left is obtained. Adjust the amount.
  • the amount of oxygen added is increased, the amount of carbon that reacts with oxygen and disappears by gasification increases, and the amount of remaining carbon decreases.
  • the amount of oxygen added is reduced, the amount of carbon that reacts with oxygen and disappears by gasification decreases, and the amount of remaining carbon increases. More specifically, it is preferably performed at 200 to 350 ° C. and oxygen of 10% or less.
  • the degreased product is post-reaction sintered in a nitrogen atmosphere. Specifically, silicon particles are nitrided at 1200 to 1400 ° C., and finally fired and sintered at 1700 to 1800 ° C. In the final sintering step, the oxide film (SiO 2 ) on the surface of the silicon nitride particles reacts with the auxiliary agent to generate glass, and the silicon nitride particles are bonded to each other by the glass.
  • FIG. 1 is a perspective view showing an overview of a honeycomb filter according to an embodiment of the present invention.
  • FIG. 2 is a schematic cross-sectional view of a plane parallel to the axial direction of the honeycomb filter.
  • the honeycomb filter 1 has a columnar honeycomb structure 10 made of a silicon nitride based porous body according to the present invention.
  • a plurality of cells 11 extending in one direction are formed inside the cylindrical main body of the honeycomb structure 10.
  • Each cell 11 has a cross-sectional shape that is substantially square in a direction perpendicular to the axial direction (cell extending direction) and is defined by a porous cell wall 12.
  • the porous cell wall 12 serves as a particulate matter (hereinafter, PM) collecting member.
  • Each cell 11 provided in the honeycomb structure 10 is sealed (sealed) by sealing a filler at one end in the axial direction (stretching direction), and a sealing portion 21 is formed. ing.
  • the sealing part 21 is provided with a plurality of cells 11 alternately at both ends in the axial direction of the honeycomb structure 10.
  • the outer peripheral portion of the honeycomb structure 10 is covered with an outer peripheral coating layer 15.
  • the outer periphery covering layer 15 is made of a ceramic layer, and is formed by firing an outer periphery covering material applied to the outer periphery of the honeycomb structure 10.
  • the outer peripheral coating layer 15 is not necessarily required.
  • description of the outer periphery coating layer 15 is abbreviate
  • the honeycomb filter 1 having such a configuration is arranged such that the axial direction, which is also the extending direction of the cells 11, is parallel to the flow of exhaust gas, as shown in FIG.
  • the exhaust gas flows in from a cell (inflow side cell) 11 that is located upstream of the flow and whose cell end is not sealed.
  • the exhaust gas that has flowed into the cell 11 passes through the micropores of the porous cell wall 12 and is located on the downstream side of the flow to the adjacent cell (outflow side cell) 11 where the cell end is not sealed. And move out of it.
  • the PM contained in the exhaust gas is collected in the cell wall 12 when the exhaust gas passes through the fine holes in the cell wall 12.
  • the collected PM is removed from the cell wall 12 by regenerating and heating the honeycomb filter 1, thereby regenerating the honeycomb filter 1.
  • the honeycomb structure 10 is exemplified as a columnar shape in which the cross-sectional shape of the surface perpendicular to the axial direction of the honeycomb filter 1 is circular, but the cross-sectional shape is not particularly limited. For example, it may be oval, square, rectangular, or polygonal.
  • Such a honeycomb structure 10 can be molded in advance into a desired shape by using an extruder. Further, the optimum value of the cross-sectional size of the plane perpendicular to the axial direction of the honeycomb filter 1 is determined by the engine displacement.
  • the cross-sectional shape of the cell 11 is preferably substantially square. However, it is not necessarily limited to this, and other shapes may be used.
  • the thickness of the cell wall 12 is not particularly limited, and may be 0.2 to 0.4 mm, for example. Further, the number of cells in the unit area is not particularly limited, and may be, for example, 200 to 300 cpsi.
  • the thickness of the outer peripheral coating layer 15 is not particularly limited, but is generally set to 0.3 mm to 1.0 mm.
  • honeycomb filter As the material of each part in the honeycomb filter 1, existing conventional materials can be used except for the honeycomb structure 10 using the silicon nitride porous body according to the present invention.
  • ceramic clay such as aluminum oxide (alumina), aluminum titanate, silicon carbide, silicon nitride, cordierite, mullite, apatite, or cement material should be used. Can do. These may be used alone or in combination. Among these, aluminum oxide is particularly preferable from the viewpoint of versatility as a cement material.
  • the outer peripheral coating layer 15 is made of a ceramic layer, and a material obtained by blending inorganic particles such as inorganic balloon, colloidal silica, bentonite, or an inorganic binder with the material of the honeycomb structure 10 described above is used.
  • the honeycomb filter 1 is a so-called integral type in which the honeycomb structure 10 is formed of one porous ceramic fired body.
  • a divided type in which a honeycomb segment body, which is a plurality of porous ceramic fired bodies formed in a prismatic shape, is bonded to each other through a joint portion may be used.
  • the silicon nitride based porous material of the present invention is a silicon nitride based porous material in which silicon nitride particles and silicon particles are used as raw materials, and the silicon nitride particles are bonded together by glass, and the silicon particles are carbonized. It is characterized in that it contains 5 to 22 wt% of silicon carbide particles and has a porosity of 40 to 70%.
  • the method for producing a silicon nitride based porous material of the present invention includes a raw material silicon nitride particle, a silicon particle, a sintering aid that reacts with SiO 2 on the surface of the silicon nitride particle to produce glass, an organic Mixing step of mixing binder material and pore former, molding step of molding the mixture obtained in the mixing step, and adjusting the amount of oxygen mixed in the atmosphere of the molding obtained in the molding step And a degreasing step for degreasing leaving a part of the organic component, and a sintering step for sintering the degreased molding obtained in the degreasing step in a nitrogen atmosphere, and the degreasing step is included after degreasing.
  • the amount of oxygen mixed in the atmosphere is adjusted so that the silicon carbide particles produced by the reaction of the organic component and the silicon particles in the sintering step are 5 to 22 wt% (weight%), and the sintering is performed.
  • the silicon particles are included after degreasing While silicon carbide particles are formed by organic components, the silicon particles are nitrided to form silicon nitride particles, and then SiO 2 and sintering aid on each surface of the raw silicon nitride particles and the nitrided silicon nitride particles formed. It reacts with an agent, produces
  • the degreasing step may be performed at a temperature range of 200 to 350 ° C. and oxygen of 10% or less. According to this, it is possible to easily adjust the remaining amount of the organic component in the degreasing step.
  • the silicon nitride based porous material of the present invention is produced by the method for producing a silicon nitride based porous material of the present invention, and has a porosity of 40 to 70%.
  • the silicon nitride based porous material produced by the production method of the present invention has excellent mechanical strength and high thermal conductivity.
  • the silicon nitride based porous body of the present invention has the above porosity, and can function stably as a DPF.
  • the porosity is less than 40%, the porosity is in the above range, and the performance of collecting the particulate matter cannot be guaranteed, and the pressure loss also increases. Conversely, if the porosity exceeds 70%, it is not possible to obtain a strength that can withstand use.
  • the present invention comprises a honeycomb structure having a plurality of cells extending in one direction formed by the silicon nitride based porous body of the present invention and partitioned by cell walls, and the honeycomb structure,
  • the honeycomb filter in which the end portions on one side in the extending direction of the plurality of cells in the honeycomb structure are alternately sealed by the sealing portions is also included in the category.
  • Extruded goblet was extruded using an extrusion die to form a honeycomb structure of 35 mm ⁇ 35 mm ⁇ 100 mm as a molded product.
  • the honeycomb structure thus formed was dried and then degreased by heating to 300 ° C. in a stream of N 2 + 5% O 2 to remove a part of methylcellulose.
  • the degreased molded product (degreasing molded product) is put in a sintering furnace, fired at a temperature of 1200 to 1400 ° C. in a nitrogen atmosphere to nitride silicon, and finally fired at 1700 ° C. for 6 hours.
  • a sample of Example 1 was obtained.
  • Example 2 using the same raw materials as in Example 1, only the amount of oxygen added to the nitrogen atmosphere in the degreasing process was adjusted, and samples of Examples 2 to 5 and Comparative Examples 1 to 3 were obtained.
  • the compressive strength, thermal conductivity, and porosity of the honeycomb structure of the example manufactured in this manner were measured.
  • the porosity was measured using an Archimedes density meter.
  • the compressive strength was measured by compressing a 35 mm square honeycomb molded body in a direction parallel to the through hole.
  • the thermal conductivity was measured using a hot disk method thermal conductivity measuring device manufactured by Kyoto Electronics Industry Co., Ltd. The sample size was set to 35 mm ⁇ 35 mm ⁇ 10 mmt.
  • Table 1 shows the measurement results.
  • the present invention can be suitably used as an exhaust gas purification filter for collecting particulate matter contained in exhaust gas of a diesel engine.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Filtering Materials (AREA)
  • Ceramic Products (AREA)
  • Porous Artificial Stone Or Porous Ceramic Products (AREA)

Abstract

Selon l'invention, dans une étape de dégraissage, la quantité d'oxygène à mélanger sous une atmosphère est ajustée de façon que la quantité de particules de carbure de silicium qui sont produites par la réaction entre un composant organique et des particules de silicium, le composant comme les particules étant présents après le dégraissage, dans une étape de frittage réalisée après l'étape de dégraissage, soit de 5 à 22 % en poids. Dans l'étape de frittage, un frittage post-réactionnel est mis en œuvre.
PCT/JP2014/057493 2013-03-28 2014-03-19 Corps poreux en nitrure de silicium, procédé de production d'un corps poreux en nitrure de silicium, structure en nid d'abeille et filtre en nid d'abeille WO2014156866A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2013070491A JP5612149B2 (ja) 2013-03-28 2013-03-28 窒化ケイ素系多孔体、窒化ケイ素系多孔体の製造方法、ハニカム構造体およびハニカムフィルタ
JP2013-070491 2013-03-28

Publications (1)

Publication Number Publication Date
WO2014156866A1 true WO2014156866A1 (fr) 2014-10-02

Family

ID=51623845

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2014/057493 WO2014156866A1 (fr) 2013-03-28 2014-03-19 Corps poreux en nitrure de silicium, procédé de production d'un corps poreux en nitrure de silicium, structure en nid d'abeille et filtre en nid d'abeille

Country Status (2)

Country Link
JP (1) JP5612149B2 (fr)
WO (1) WO2014156866A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06116038A (ja) * 1992-09-30 1994-04-26 Mitsubishi Gas Chem Co Inc 窒化ケイ素−炭化ケイ素複合焼結体の製造法
JPH08217568A (ja) * 1995-02-08 1996-08-27 Denki Kagaku Kogyo Kk 多孔質導電性炭化珪素焼結体の製造方法
JP2002201083A (ja) * 2000-12-28 2002-07-16 National Institute Of Advanced Industrial & Technology セラミックス多孔体及びその製造方法
JP2003146763A (ja) * 2001-08-29 2003-05-21 Corning Inc 窒化ケイ素−炭化ケイ素複合体フィルタの製造方法
JP2010235421A (ja) * 2009-03-31 2010-10-21 National Institute Of Advanced Industrial Science & Technology 窒化ケイ素フィルターの製造方法及び窒化ケイ素フィルター

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06116038A (ja) * 1992-09-30 1994-04-26 Mitsubishi Gas Chem Co Inc 窒化ケイ素−炭化ケイ素複合焼結体の製造法
JPH08217568A (ja) * 1995-02-08 1996-08-27 Denki Kagaku Kogyo Kk 多孔質導電性炭化珪素焼結体の製造方法
JP2002201083A (ja) * 2000-12-28 2002-07-16 National Institute Of Advanced Industrial & Technology セラミックス多孔体及びその製造方法
JP2003146763A (ja) * 2001-08-29 2003-05-21 Corning Inc 窒化ケイ素−炭化ケイ素複合体フィルタの製造方法
JP2010235421A (ja) * 2009-03-31 2010-10-21 National Institute Of Advanced Industrial Science & Technology 窒化ケイ素フィルターの製造方法及び窒化ケイ素フィルター

Also Published As

Publication number Publication date
JP5612149B2 (ja) 2014-10-22
JP2014193783A (ja) 2014-10-09

Similar Documents

Publication Publication Date Title
JP6912412B2 (ja) 炭化珪素質多孔体及びその製造方法
WO2006001509A1 (fr) Procédé de production de corps poreux, corps poreux, et corps structurel alvéolaire
JP6654085B2 (ja) 多孔質材料、及び多孔質材料の製造方法並びにハニカム構造体
WO2001079138A1 (fr) Structure en nid d'abeille et son procede de production
JP5095215B2 (ja) 多孔体の製造方法、多孔体及びハニカム構造体
WO2007116665A1 (fr) Element raccord, element raccord d'un segment en nid d'abeille et structure en nid d'abeille ainsi obtenue
WO2003062611A1 (fr) Structure en nid d'abeilles contenant si et son procede de fabrication
WO2009118862A1 (fr) Procédé de production d'une structure en nid d'abeilles
JP5193804B2 (ja) 炭化珪素質多孔体及びその製造方法
JP2004261623A (ja) ハニカム構造体
JP2010516621A (ja) 押出成形した繊維状炭化ケイ素基材およびその製造方法
JP5193805B2 (ja) 炭化珪素質多孔体及びその製造方法
JP5292070B2 (ja) 炭化珪素質多孔体及びその製造方法
JP2020049428A (ja) ハニカムフィルタ
JP4900820B2 (ja) セラミックハニカムフィルタ
JP4465435B2 (ja) セラミックフィルター及びその製造方法
JP2013202532A (ja) ハニカムフィルタ
JP5190878B2 (ja) ハニカム構造体
JP5612149B2 (ja) 窒化ケイ素系多孔体、窒化ケイ素系多孔体の製造方法、ハニカム構造体およびハニカムフィルタ
JP2012045926A (ja) グリーン成形体
JP2015193489A (ja) 窒化ケイ素系多孔体およびその製造方法
JP5053981B2 (ja) 炭化珪素質多孔体及びその製造方法
JP6084497B2 (ja) ハニカムフィルタ
JP2014193782A (ja) 多孔質焼結体、多孔質焼結体の製造方法、ハニカム構造体およびハニカムフィルタ
KR20090048110A (ko) 비대칭 밀봉으로 배압차를 개선한 허니컴 구조체 및 그제조방법

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: 14774356

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 14774356

Country of ref document: EP

Kind code of ref document: A1