685 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 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 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.

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 (t_s′>5 t_w′) 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.