Porous material and method for production thereof

• US 20050143255A1
• Filed: 03/27/2003
• Published: 06/30/2005
• Est. Priority Date: 03/29/2002
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Morimoto, Kenji, Inoue, Katsuhiro
• Granted Patent: US 7,473,464 B2
• Time in Patent Office: Days
• US Class Current: 502/178
• CPC Class Codes: B01D 39/2093 Ceramic foam
• CPC Class Codes: B01D 53/94 by catalytic processes
• CPC Class Codes: B01J 35/10 characterised by their surface properties or porosity
• CPC Class Codes: B01J 35/60 characterised by their surface properties or porosity
• CPC Class Codes: B01J 37/0009 Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
• CPC Class Codes: C04B 2111/00793 as filters or diaphragms
• CPC Class Codes: C04B 2235/3201 Alkali metal oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3418 Silicon oxide, silicic acids, or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint glass constituents C04B2235/36
• CPC Class Codes: C04B 2235/3445 Magnesium silicates, e.g. forsterite
• CPC Class Codes: C04B 2235/3481 Alkaline earth metal alumino-silicates other than clay, e.g. cordierite, beryl, micas such as margarite, plagioclase feldspars such as anorthite, zeolites such as chabazite
• CPC Class Codes: C04B 2235/3826 Silicon carbides
• CPC Class Codes: C04B 2235/528 Spheres
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/6021 Extrusion moulding
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/80 Phases present in the sintered or melt-cast ceramic products other than the main phase
• CPC Class Codes: C04B 35/195 Alkaline earth aluminosilicates, e.g. cordierite or anorthite
• CPC Class Codes: C04B 35/565 based on silicon carbide
• CPC Class Codes: C04B 38/0051 : characterised by the pore size, pore shape or kind of porosity
• CPC Class Codes: C04B 38/0054 : the pores being microsized or nanosized
• CPC Class Codes: C04B 38/0074 : expressed as porosity percentage
• CPC Class Codes: F01N 2330/06 : Ceramic, e.g. monoliths
• CPC Class Codes: F01N 3/0222 : the structure being monolithic, e.g. honeycombs
• CPC Class Codes: F01N 3/2828 : Ceramic multi-channel monoliths, e.g. honeycombs
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies
• CPC Class Codes: Y10T 428/24149 : Honeycomb-like
• CPC Class Codes: Y10T 428/249953 : Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/249954 : With chemically effective material or specified gas other than air, N, or carbon dioxide in void-containing component

Abstract

According to the present invention, a porous material is characterized by comprising: a connected structure formed by combining silicon carbide which is an aggregate with cordierite which is a combining material in a state to hold a large number of pores, and having a porosity of 52 to 70% and a median pore diameter of 15 to 30 μm, and is a porous material having a high porosity and a high strength and having a remarkably low possibility of including defective portions such as cuts and the like causing liquid leakage in a case where the material is used as a filter.

Claims

1. A porous material comprising:

a connected structure formed by combining silicon carbide which is an aggregate with cordierite which is a combining material in a state to hold a large number of pores,

characterized in that the material has a porosity of 52 to 70% and a median pore diameter of 15 to 30 μ

m.

2. The porous material according to claim 1, wherein a ratio of a content of silicon carbide to a total content of cordierite and silicon carbide is 5 to 70% by volume.

3. The porous material according to claim 1, wherein a ratio of a volume of pores each having a diameter of 50 μ

m or more to a total volume of pores is 10% by volume or less.

4. The porous material according to claim 1, wherein a median particle diameter of silicon carbide is 10 to 50 μ

m.

5. A method of manufacturing a porous material using silicon carbide which is an aggregate, and a cordierite forming material containing an Al source, an Si source, and an Mg source and forming cordierite by firing,

characterized in that an inorganic micro balloon containing SiO₂ and Al₂O₃ is used as a part or all of the Al source and the Si source.

6. The method of manufacturing the porous material according to claim 5, wherein a total content of the Si source and the Al source contained in the inorganic micro balloon with respect to the whole inorganic micro balloon is 90% by mass or more, when the Si source is converted to SiO₂, and the Al source is converted to Al₂O₃.

7. The method of manufacturing the porous material according to claim 5, wherein a total content of a sodium compound and a potassium compound contained in the inorganic micro balloon with respect to the whole inorganic micro balloon is 2% by mass or less, when the sodium compound is converted to Na₂O, and the potassium compound is converted to K₂O.

8. The method of manufacturing the porous material according to claim 5, wherein a melting point of the inorganic micro balloon is 1400°

C. or more.

9. The method of manufacturing the porous material according to claim 5, wherein Mg(OH)₂ and/or MgCO₃ is used as a part or all of the Mg source.

10. The method of manufacturing the porous material according to claim 5, wherein silicon carbide is spherical, and has a median particle diameter of 10 to 50 μ

m.