695 results about "Ceramic honeycomb" patented technology

A ceramic honeycomb structural body is manufactured by molding silicon carbide raw powders into a honeycomb pillar shape and then firing it to form a sintered body. The silicon carbide raw powders are comprised of about 60 to about 80% by mass of particles of first particle group having one frequency peak in the particle size distribution and a particle size of 1.0 μm to about 100 μm, and about 20 to about 40% by mass of particles of a second particle group having a particle size of about 0.1 μm or more and less than 1.0 μm.

A honeycomb structural body comprises one or plural pillar-shaped porous ceramic members in which many through-holes are arranged side by side in a longitudinal direction through partition walls and either one end portions of these through-holes are sealed. The partition wall forming the structural body has a surface roughness of not less than 10 μm as a maximum roughness Rz defined in JIS B0601-2001 and an average pore size of 5-100 μm in a pore distribution measured by a mercury pressure method, and satisfies the following relationship: A≧90−B / 20 or A≦100−B / 20 when a ratio pores having a pore size of 0.9-1.1 times the average pore size to total pore volume is A (%) and a thickness of the partition wall is B (μm), and there is proposed an effective honeycomb structural body having excellent pressure loss and catching efficiency and a high catalyst reactivity.

A ceramic honeycomb substrate for use in an automotive catalytic converter system which exhibits improved light-off performance by virtue of a high porosity of 45 to 75% while still maintaining a wall thickness of greater than 2.0 mil (0.0020 inch, 0.0508 mm), preferably 2.5 mil (0.0025 in., 0.0635 mm) to 7 mil (0.0070 in., 0.1778 mm), and more preferably 2.5 mil (0.0025 in., 0.0635 mm) to 3 mil (0.0030 in., 0.0762 mm). The median pore size is in the range of 2-10 micrometers, and a coefficient of thermal expansion (CTE) (25-800° C.) of less than 15×10−7 / ° C.

A continuous firing furnace of the present invention comprises: a muffle formed into a cylindrical shape so as to ensure a predetermined space; a plurality of heat generators placed at the peripheral direction from the muffle; and a heat insulating layer formed in a manner so as to enclose said muffle and said heat generators therein, said continuous firing furnace being configured such that a formed body to be fired, which is transported from an inlet side, passes through the inside of said muffle at a predetermined speed in an inert gas atmosphere and, then, is discharged from an outlet so that said formed body is fired, wherein said inert gas flows through: a space between said muffle and said heat insulating layer; and a space inside the muffle, in sequence.

A ceramic honeycomb filter comprising a ceramic honeycomb structure having porous partition walls defining a plurality of flow paths for flowing an exhaust gas through the porous partition walls to remove particulates from the exhaust gas, the predetermined flow paths among the flow paths being sealed at their ends, a catalyst being carried by the porous partition walls, the porous partition walls having a porosity of 60-75% and an average pore diameter of 15-25 mum when measured according to a mercury penetration method, and the maximum of a slope Sn of a cumulative pore volume curve of the porous partition walls relative to a pore diameter obtained at an n-th measurement point being 0.7 or more, the Sb being represented by the following formula (1): Sn=-(Vb-Vn-1) / [log Dn-log (Dn-1)] (1), wherein Dn is a pore diameter (mum) at an n-th measurement point, Dn-1 is a pore diameter (mum) at an (n-1)-th measurement point, Vn is a cumulative pore volume (cm3 / g) at an n-th measurement point, and Vn-1 is a cumulative pore volume (cm3 / g) at an (n-1)-th measurement point.

A porous cordierite ceramic honeycomb article with increased mechanical strength and thermal shock resistance. The porous cordierite ceramic honeycomb article has MA<2220, or MT>2660 wherein MA=3645 (IA)−106 (CTE)+19 (d90)+17 (% porosity), MT=4711 (IT)+116 (CTE)−26 (d90)−28 (% porosity), and a CTE≦9×10−7 / ° C. in at least one direction. A method of manufacturing is also disclosed wherein the inorganic raw material mixture contains talc, an alumina-forming source, a silica-forming source, and 0-18 wt. % of a kaolin or calcined kaolin containing not more than 8 wt. % of a fine kaolin source having a median particle diameter of less than 7 μm, wherein the fired porous ceramic cordierite honeycomb article has a porosity<54% . Alternatively, if greater than 8 wt. % of the fine kaolin source is used, then a slow ramp rate is utilized from 1200° C. to 1300° C. of not more than 20° C. / hr.

A ceramic honeycomb filter comprising pluralities of ceramic honeycomb structures each having large numbers of flow paths partitioned by cell walls, which are bonded in the direction of the flow paths, predetermined flow paths being sealed by plugs, plugs formed at one end of at least one honeycomb structure being bonded to at least part of plugs formed at one end of a honeycomb structure adjacent to the end of this honeycomb structure.

Substantially non-microcracked, porous, cordierite ceramic honeycomb bodies are provided. Although exhibiting moderately high thermal expansion (CTE) between 7×10−7 to 16×10−7 / ° C. (25-800° C.), the honeycomb bodies exhibit relatively high thermal shock parameter (TSP), such as TSR≧525° C. by virtue of a high MOR / E ratio, and / or low Eratio=ERT / E1000° C. and well interconnected porosity, as witnessed by a relatively high pore connectivity factor (PCF). A method of manufacturing the honeycomb ceramic structure is also provided.

Disclosed are ceramic honeycomb articles, which are composed predominately of a crystalline phase cordierite composition. The ceramic honeycomb articles possess a microstructure characterized by a unique combination of relatively high total porosity of less than 54%, and relatively narrow pore size distribution having a d10 pore diameter of not less than 8 μm, a d90 pore diameter of not greater than 35 μm, and a value of df=(d50−d10) / d50 of less than 0.50. The articles exhibit high thermal durability and high filtration efficiency coupled with low pressure drop across the filter. Such ceramic articles are particularly well suited for filtration applications, such as diesel exhaust filters or DPFs. Also disclosed are methods for manufacturing the ceramic articles of the present invention.

The invention relates to a high-performance natural gas vehicle tail-gas clean-up catalyst and preparation method thereof, wherein the catalyst has higher catalytic conversion performance to CO, HC, NOx, especially capable of effectively conversing methane at low temperature. The catalyst comprises a first carrier, a second carrier on the first carrier and active components, characterized in that: the second carrier comprises a molecular sieve modified by the metal oxides and cerium zirconium solid solution; the active components comprise two or three kinds of noble metal platinum, palladium and rhodium. The first carrier is cordierite ceramic honeycomb carrier and the second carrier loads and the cerium, zirconium solid solution loaded with one or more than one noble metal selected from the platinum, palladium and rhodium is used as the first layer load on the cordierite ceramic honeycomb carrier and the molecular sieve modified by the metal oxide and loaded with one or more than one noble metal selected from the platinum, palladium and rhodium is used as the second layer load on the first load.

A catalyst support structure for use as either a NOx catalyst support or as a DPF including (i) a multicellular ceramic body, preferably a monolithic ceramic honeycomb composed e.g., of cordierite or aluminum titanate, and (ii) a hydrophobic coating on at least the exterior surface thereof which results in a ceramic honeycomb exhibiting reduced or low absorption when exposed to both liquid catalytic coating media and aqueous media utilized in the process of applying the catalytic coating. In a preferred embodiment the hydrophobic coating is formed within or on an applied external skin layer provided on the multicellular ceramic body.

A method for producing a ceramic honeycomb filter having large numbers of flow paths partitioned by cell walls, the flow paths having plugs at positions separate from an end surface of the honeycomb filter, comprising the steps of introducing a base-forming material into the flow paths on one end surface side, charging a plug-forming material into flow paths to be provided with plugs from the other end surface side, and sintering it.

Disclosed is a method and apparatus for forming a circumferential skin surrounding a central cellular structure of an extruded honeycomb article. The method and apparatus may be used to produce defect-free skins and / or skins having large thickness and a high degree of particle alignment thereby preferably exhibiting CTE comparable to the extruded webs. These benefits are achieved by providing a die and method wherein a flow, Q, exiting any two active ones of a plurality of peripheral slots forming the skin is substantially equal. Also disclosed is a thick-skinned ceramic article having a thick extruded skin (ts′>5 tw′) with an I-value comparable to the webs.

A ceramic honeycomb structure (1) constituted by cell walls (ribs) (2) forming a composite structure from a plurality of cells (3) being adjacent each other and a honeycomb outer wall (4) surrounding and holding the outermost peripheral cells located at the circumference of the composite structure; said composite structure satisfying the followings: the basic thickness of the cell walls (2) (the basic cell wall thickness) (Tc) is Tc<=0.12 mm, the outer wall thickness (Ts) of the honeycomb structure is Ts >=0.05 mm, and the open frontal area (P) is P>==80%, and there is a relation shown by formula: <paragraph lvl="0"><in-line-formula>1.10<=(Tr1~Tr3-20) / Tc<=3.00 < / in-line-formula>between the basic cell wall thickness (Tc) and each cell wall thickness (Tr1~Tr3-20) of cells existing between an outermost peripheral cell and any cell within a first end cell from a fifth cell to a twentieth cell extending inwardly, taking the outermost peripheral cell as a first staring cell.

A coating material of the present invention is a coating material comprising: cordierite powder as a main component having a tap bulk density of 1.3 g / cm3 or more; and water. The coating material is capable of forming a coated wall (outer wall), for example, on the surface of a porous body formed of a ceramic in such a manner that defects such as generation of cracks, and peeling, and a manufacturing yield is satisfactory are not easily generated.

The invention discloses a manganese oxide molecular sieve-doped monolithic catalyst for decomposing ozone (O3) at room temperature and a preparation method thereof, which relates to the fields of catalysis and environmental protection. The preparation method is characterized in that a ceramic honeycomb monolithic type or porous foam metal carrier is adopted, and the manganese oxide molecular sieve doped with cobalt or titanium is taken as an active component. The manganese oxide molecular sieve doped with the cobalt or titanium is characterized in that: 1) the manganese oxide molecular sieve has Hollandite-typed manganese oxide octahedral molecular sieves (OMS-2) structure, the pore size is about 0.46nm multiplied by 0.46nm; 2) cobalt or titanium ions are introduced on a framework of the Hollandite-typed manganese oxide octahedral molecular sieves to form the manganese oxide molecular sieve doped with cobalt or titanium. An ozone decomposition catalyst is prepared by an oxidation reduction-refluxing method or an oxidation reduction-hydrothermal synthesis method, namely, the solution with manganese salt and cobalt salt or titanium salt is added with a strong oxidizer to synthesize the ozone decomposition catalyst by refluxing at the temperature of 90-200 DEG or hydrothermal process for more than 12 hours. The monolithic catalyst is characterized in that the input of additional energy sources such as light, heat, electricity, and the like, is unnecessary, and the ozone can be stably decomposed into oxygen under the conditions of normal temperature, normal humidity and large air volume.

A ceramic honeycomb structure comprising a ceramic honeycomb body comprising axial grooves on its periphery and cell walls constituting a larger number of flow paths inside the grooves, and a peripheral wall layer covering the grooves, wherein there are stress release portions at least partially in the peripheral wall layer and / or between the peripheral wall layer and the grooves. The thermal expansion coefficient of the peripheral wall layer is preferably smaller than those of the cell walls in a radial direction. The peripheral wall layer is preferably formed on the ceramic honeycomb body formed by removing a peripheral wall from a ceramic green body, before or after firing the ceramic honeycomb body.

Diesel engine exhaust filtration systems, and ceramic honeycomb wall flow exhaust filters for such systems, wherein the filters comprise axially centralized filter sections having a higher heat capacity and / or a higher gas flow resistance than peripheral filter sections disposed radially outwardly thereof, the filters thereby exhibiting increased resistance to thermal damage from filter regeneration over-heating.

The invention relates to a process for coating ceramic honeycomb bodies with a catalyst suspension comprising catalyst components as solids and / or in dissolved form in a carrier liquid. Parallel flow channels run through the honeycomb bodies. The walls of the flow channels have an open pore structure. To coat the channel walls and in particular also the interior surfaces of the pores with the catalyst suspension, the entry and exit end faces of the vertically aligned honeycomb bodies are each brought into contact with a perforated mask, with the perforated masks being arranged so that the open regions of the perforated mask on the one end face are opposite the closed regions of the perforated mask on the other end face and vice versa. The catalyst suspension is then pumped or sucked from below into the honeycomb bodies until it exits at the upper end face. Excess suspension is then removed by blowing-out or sucking-out, the contact with the perforated masks is released and the honeycomb body is calcined to fix the coating.

A process for coating the slurry on the surface of cellular ceramic carrier inclues such steps as arranging the cellular ceramic carrier to a particular working position by automatic fixture, sealing it, delivering the slurry via tube, negative-pressure coating, and positive-pressure scavenge to remove excessive slurry.

A ceramic honeycomb filter comprising a sintered ceramic honeycomb body having porous partition walls defining flow paths, and plugs formed in predetermined flow paths for removing particulate matter from an exhaust gas passing through the porous partition walls, the sintered ceramic honeycomb body being formed by a cordierite-based ceramic material, at least part of the plugs comprising ceramic particles and an amorphous oxide matrix formed from colloidal oxide.