Ngk Insulators, Inc.

Yukari Nakane

Yasushi Noguchi

Takehiko Watanabe

Yukio Miyairi

Toshio Yamada

Naomi Noda

Takeshi Tokunaga

Yukio Mizuno

A process for producing a honeycomb structure includes: a mixing step where forming raw materials including a ceramic raw material are mixed to obtain a forming blended material, a kneading step where the forming blended material is kneaded to obtain kneaded clay, a forming step where the kneaded clay is formed into a honeycomb shape to obtain a honeycomb formed article, and a firing step where the honeycomb formed article is fired to obtain a honeycomb structure. The ceramic raw material is a cordierite forming raw material, and a magnetic powder contained in the kneaded clay is at a ratio of 400 ppm or less with respect to solid content conversion mass of the whole kneaded clay. There is provided a honeycomb structure capable of improving trapping efficiency, in particular, initial trapping efficiency by reducing the number of coarse pores in the partition walls.

Process for producing honeycomb structure

A honeycomb structureof the present invention is provided with porous partition wallsmade of a ceramic material containing cordierite as a main crystal phase and separating and forming a plurality of cellsfunctioning as fluid passages. The partition wallscontain sodium at 0.08 to 0.15 mass % in terms of sodium oxide. A honeycomb structure having a large average pore size can be provided.

Honeycomb structure and method for manufacturing the same

A honeycomb filter including partition walls having a porous partition wall base material and a surface layer provided on only inflow side or both inflow and outflow sides of the partition wall base material, and satisfying the following conditions capable of using as a DPF. The surface layer has a peak pore diameter of from 0.3 &#x3bc;m to 20 &#x3bc;m (exclusive) being equal to or smaller than the average pore diameter of the base material; the porosity of from 60% to 95% (exclusive) when measured by mercury porosimetry being larger than that of the base material; and the thickness Lof from 0.5% to 30% (exclusive) of the partition wall thickness L; and mass per filtration area of from 0.01 mg/cmto 6 mg/cm(exclusive). The base material has an average pore diameter of from 10 &#x3bc;m to 60 &#x3bc;m (exclusive) and a porosity of from 40% to 65% (exclusive).

Honeycomb filter

A process for producing a honeycomb structure by obtaining clay from a cordierite-forming raw material containing an alumina source, a silica source, and a magnesia source; and forming the clay into a honeycomb shape, wherein a material having, in its volume particle size distribution, a 50 volume % particle size (V50) [&#x3bc;m] of 1 to 25 &#x3bc;m is used, as each of alumina source, silica source, and magnesia source; and a material having, in the volume particle size distribution of the whole cordierite-forming raw material, a ratio of 90 volume % particle size (V90) [&#x3bc;m] to 10 volume % particle size (V10) [&#x3bc;m] [a volume particle size distribution ratio (V90/V10)] of 10 or less and a difference (V90&#x2212;V10) between 90 volume % particle size (V90) [&#x3bc;m] and 10 volume % particle size (V10) [&#x3bc;m] of 25 &#x3bc;m or less is used, as the cordierite-forming raw material.

Growing community of inventors

Nagoya, Japan

Yukari Nakane