Cordierite-type ceramic honeycomb structure and its production method

Patent metadata

Field	Value
Publication number	US-9708958-B2
Application number	US-201414896808-A
Country	US
Kind code	B2
Filing date	Sep 24, 2014
Priority date	Sep 24, 2013
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A cordierite-type ceramic honeycomb structure having large numbers of flow paths partitioned by porous cell walls; the cell walls having (a) porosity of more than 65% and 75% or less, (b) in a pore diameter distribution measured by mercury porosimetry, (i) a pore diameter d 10 at a cumulative pore volume corresponding to 10% of the total pore volume being less than 50 μm, a pore diameter (median pore diameter) d 50 at 50% being 18-27 μm, a pore diameter d 90 at 90% being 10 μm or more, and (d 10 −d 90 )/d 50 being 2.3 or less; (ii) σ[=log(d 20 )−log(d 80 )] being 0.25 or less, wherein σ represents the difference between a logarithm of a pore diameter d 20 at a cumulative pore volume corresponding to 20% of the total pore volume and a logarithm of a pore diameter d 80 at a cumulative pore volume corresponding to 80% of the total pore volume; and (iii) the maximum of the inclination S n =−(V n −V n−1 )/[log(d n )−log(d n−1 )] of a curve of a cumulative pore volume to a pore diameter being 3 or more, wherein d n and V n are respectively a pore diameter and a cumulative pore volume at an n-th measurement point, and d n−1 and V n−1 are respectively a pore diameter and a cumulative pore volume at a (n−1)-th measurement point.

First claim

What is claimed is:

1. A ceramic honeycomb structure having a plurality of flow paths partitioned by porous cell walls comprising cordierite,
(a) said cell walls having porosity of more than 65% and 75% or less; and
(b) in a pore diameter distribution measured by mercury porosimetry,
(i) a pore diameter d 10 at a cumulative pore volume (cumulative volume of pores in a range from the maximum pore diameter to a particular pore diameter) corresponding to 10% of the total pore volume being less than 50 μm,
a pore diameter (median pore diameter) d 50 at 50% being 18 μm or more and 27 μm or less,
a pore diameter d 90 at 90% being 10 μm or more, and
(d 10 −d 90 )/d 50 being 2.3 or less;
(ii) σ[=log(d 20 ) −log(d 80 )] being 0.25 or less, wherein σ represents the difference between a logarithm of a pore diameter d 20 at a cumulative pore volume corresponding to 20% of the total pore volume and a logarithm of a pore diameter d 80 at a cumulative pore volume corresponding to 80% of the total pore volume; and
(iii) the maximum of the inclination S n =−(V n −V n−1 )/[log(d n )−log(d n−1 )] of a curve of a cumulative pore volume to a pore diameter being 3 or more, wherein d n and V n are respectively a pore diameter and a cumulative pore volume at an n-th measurement point, and d n−1 and V n−1 are respectively a pore diameter and a cumulative pore volume at a (n−1)-th measurement point.

2. The ceramic honeycomb structure according to claim 1 , wherein pores open on the cell wall surfaces have (i) an opening area ratio of 25-50%, and (ii) an area-based median opening diameter (expressed by equivalent circle diameter) of 25-50 μm.

3. The ceramic honeycomb structure according to claim 1 , wherein the maximum of said S n is 3.5 or more.

4. The ceramic honeycomb structure according to claim 1 , wherein the maximum of said S n is 4.0 or more.

Assignees

• Hitachi Metals Ltd

Inventors

• Okazaki Shunji

Classifications

• B01J35/57

  Honeycombs · CPC title

• C04B20/1055

  with inorganic materials · CPC title

• B01D2046/2437

  Operations & Transport · mapped topic

• C04B38/0074

  expressed as porosity percentage · CPC title

• B28B3/20

  wherein the material is extruded {(extrusion moulding of plastics B29C48/00)} · CPC title