Ngk Insulators, Inc.

Yukihisa Wada

Takahisa Kaneko

Masayuki Nate

Yasushi Noguchi

Yoshinori Yamamoto

Yumi Toda

Takashi Harada

Shuichi Ichikawa

Kazuhiko Kumazawa

Tomohiro Iida

Jun Fujita

Osamu Horikawa

Aiko Otsuka

Yumi Muroi

Jiro Maeda

Sueharu Jikumaru

Yuji Tasaki

Shinobu Naito

Makoto Osamura

There is disclosed a method of manufacturing a porous ceramic structure, comprising the steps of: preparing a formed structure using a ceramic material containing a pore former and a binder; and drying and firing the formed structure, wherein the process of firing the formed structure comprises the steps of: holding a firing atmosphere temperature in a temperature range of &#x2212;50 to +10&#xb0; C. with respect to a combustion start temperature of the binder from the time when the temperature reaches the combustion start temperature of the binder contained in the porous ceramic structure to be fired to the time when the binder is burnt out. According to this method, ceramic structures having not only a low porosity but also a high porosity can be manufactured without generating any crack during the firing.

Method of manufacturing porous ceramic body

The present invention provides a method for manufacturing a honeycomb structure, the method including steps of: forming, by extrusion, a formed bodyhaving an outer wall, partition walls provided inside the outer wall, and cells each surrounded by the partition walls as well as extending to an axial direction of the body; and drying the formed body. The method for manufacturing the honeycomb structure is characterized in that the forming step includes receiving the formed body on a cradlewhich receives the formed body so that an angle of a faceof the outer wall on the cradlerelative to the horizontal plane is 15 to 35 degrees, a cradle which has a V-shaped cross section with a cut at an apex of the V shape and which receives the formed body so that the angle relative to the horizontal plane is 15 to 45 degrees, or a cradle which receives one face of the formed body and characterized in that the drying step includes drying the formed bodyin a state of being received on the cradlehaving the predetermined angle. The method for manufacturing the honeycomb structure reduces distortion and deformation of the honeycomb structure.

Method for manufacturing honeycomb structure

A method for manufacturing a porous ceramic structure which can produce a high porosity ceramic structure as well as a low porosity ceramic structure without causing cracks at the time of firing. A method for manufacturing a porous ceramic structure comprising molding a raw material which contains a ceramic material as a main component and a pore-forming agent and then drying and firing the obtained molded article. When the molded article is fired, the temperature of a firing environment is raised substantially in synchronization with the temperature of the central portion of the molded article within a temperature range in which at least a portion of the molded article is shrunk by firing.

Method for manufacturing a porous ceramic structure

Respective pieces of the porous honeycomb segments () are stacked while interposing the adhesive layers between respective adhered surfaces (), and are bonded together by performing main pressurization (F, F) on the whole through the porous honeycomb segments () located on an outermost layer after stacking a predetermined number of pieces. Main pressurization force at this time is simultaneously applied to all the honeycomb segments () and does not act as a separating force against any of the honeycomb segments ().

Bonding method of ceramic honeycomb structure

There is disclosed a die for forming a honeycomb structure and a method of manufacturing the honeycomb structure by use of the die, in which variations of cell pitches are suppressed in a central portion and the vicinity of an outer periphery after drying and firing an extruded honeycomb structure, and the honeycomb structure having a uniform cell pitch can be manufactured. A diefor forming a honeycomb structure has a front surface provided with groovy slitsformed between cell blocksand a back surface provided with back holescommunicating with the slits. The diehas a structure in which a pitch P of the adjacent cell blocksis enlarged from a central portion of the front surface toward an outer periphery in a stepwise manner.

Die for forming honeycomb structure and method of manufacturing honeycomb structure

A method of producing a honeycomb structure of the present invention includes the steps of: forming plugged portions by dipping an end face of a honeycomb structure in slurry in a container, and pressing the honeycomb structure against an inner bottom surface of the container to force the slurry into at least some of the cells; and bringing out the honeycomb structure from the container to obtain the honeycomb structure having at least some of the cells being plugged. An air layer is formed between the plugged portions and the inner bottom surface of the container to separate them from each other in advance of bringing out the honeycomb structure having plugged portions from the container.

Method of plugging at least some of the cells of a honeycomb structure

There is disclosed a die cleaning method for removing a forming-material from a die used in forming the forming-material containing a binder, comprising the steps of: removing a part or all of the binder contained in the forming-material from the die; and removing the forming-material from the die, whereby the forming-material in the die can be removed without damaging or deforming the die for use in forming the forming-material containing the binder.

Die cleaning method

A honeycomb structurehas a large number of through-holesdivided by partition wallsand extending in the axial direction, characterized in that the honeycomb structure contains a Si phase having a lattice constant controlled at 0.54302 to 0.54311 nm at room temperature. A process for producing the honeycomb structure, includes a firing step of firing a precursor of honeycomb structure, wherein the precursor contains a Si phase and the firing step is conducted using a furnace material free from any boron-containing compound. A process for producing the honeycomb structure, includes a firing step of firing a precursor of honeycomb structure, wherein a reduction percentage of Si content in Si phase after firing step relative to Si content in Si phase before firing step is suppressed at 10% by mass or less. Having an improved thermal conductivity, the honeycomb structure is superior in thermal shock resistance.

Si-containing honeycomb structure and process for production thereof

There are provided a porous honeycomb structure body capable of satisfying a pressure loss and isostatic strength which are mutually contradictory properties simultaneously and a method for manufacturing the same. In a porous honeycomb structure body having partition walls which contain cordierite as a primary crystal phase and have a porosity of 40 to 75% and an average pore diameter of 10 to 50 &mgr;m, porosity and an average pore diameter in a center portion of the structure body are made larger than porosity and an average pore diameter in a peripheral portion of the structure body.

Porous honeycomb structure body, the use thereof and method for manufacturing the same

A process for producing a ceramic structural body, including the steps of formulating a ceramic body by incorporating 0.2 to 3 wt % of emulsified wax and 2 to 7 wt % of methyl cellulose and plasticizing the resulting mixture for extrusion, and extruding the ceramic body.

Production of ceramic structural bodies

A process for producing a ceramic honeycomb structural body, comprises the steps of placing a green ceramic honeycomb structural body on a ceramic plate, and then firing the green ceramic honeycomb structural body. The green ceramic honeycomb structural body is placed on the ceramic plate in the state that a cell-opened end face contacts the ceramic plate. The ceramic plate is composed mainly of heat-resistive inorganic fibers, and has a bulk density of not less than 1.00 g/cm.sup.3.

Process for producing ceramic honeycomb structural bodies

A drying carrier adapted for carrying honeycomb structures includes a plurality of perforated plates spaced to each other in the longitudinal direction of the drying carrier and made of a material having a conductivity higher than that of the drying carrier. Each of said perforated plates is provided with a convex portion having an upper contacting surface to be contacted with the bottom surface of the honeycomb structure to be carried. The surface area (A) of the upper contacting surface of the convex portion is smaller than the bottom surface area of the honeycomb structure.

Drying carrier adapted for carrying honeycomb structure

A ceramic honeycomb structural body-firing process includes the steps of: formulating a raw material from talc, kaolin and other cordierite-forming materials to give cordierite having a chemical composition of SiO.sub.2 : 42-56% by weight, Al.sub.2 O.sub.3 : 30-45% by weight and MgO: 12-16% by weight as a main component and a crystalline phase mainly composed of cordierite, shaping a honeycomb structural body from the resulting mixture by extrusion, and firing the honeycomb structural body. In the firing step, a heating rate in a temperature range in which the honeycomb structural body is thermally shrunk is set at not less than 20.degree. C./hr but not more than 60.degree. C./hr, the heating rate in a temperature range in which the solid phase reaction of the honeycomb structure body proceeds is set at not less than 80.degree. C./hr but not more than 130.degree. C./hr, and the heating rate in a temperature range in which the liquid phase reaction of the honeycomb structural body proceeds is set at not less than 20.degree. C./hr but not more than 60.degree. C./hr.

Process for firing ceramic honeycomb structural bodies

An excellent method of firing ceramic materials is provided wherein bending or deformation of a supporting plate which supports a green shaped body of the ceramic materials, deformation of the green shaped body caused by its own weight, and cracks and breakage of fired shaped body, during the firing of the shaped body of the ceramic materials, are eliminated. The method comprises mounting a green supporting plate on a fired supporting plate, mounting a green structural body of ceramic raw materials on the green supporting plate, and firing the green structural body on the green supporting plate.

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Nagoya, Japan

Yukihisa Wada