A honeycomb body with a honeycomb structure having an inner zone of a first plurality of walls and an outer zone of a second plurality of walls at least partially surrounding the inner zone. The honeycomb structure has Pi that is greater than Po and MPSi that is greater than MPSo, wherein Pi is an average bulk porosity of the first plurality of walls, Po is an average bulk porosity of the second plurality of walls, MPSi is a median pore size of pores in the first plurality of walls, and MPSo is a median pore size of pores in the second plurality of walls. Various honeycomb structures, honeycomb extrusion apparatus, and co-extrusion methods are disclosed.

The honeycomb structure includes a pillar-shaped honeycomb structure body that includes a porous partition wall. When the thickness (μm) of the partition wall is defined as T.sub.1 and, among pores formed in the partition wall, the value of an average pore diameter (μm) of specific pores whose pore diameters measured by a mercury press-in method are 20 to 100 μm is defined as D.sub.(20 to 100), T.sub.1/D.sub.(20 to 100) that is a value obtained by dividing T.sub.1 by D.sub.(20 to 100) is not less than 2.4, a ratio of a pore volume of the specific pores to an overall pore volume of the partition wall is 5 to 45%, and a ratio of a pore volume of large pores whose pore diameters are not less than 100 μm to the overall pore volume of the partition wall is not more than 5%.

Provided is an exhaust gas purification device that ensures an improved purification performance and a suppressed pressure loss. An exhaust gas purification device of the present disclosure includes a honeycomb substrate and an inflow cell side catalyst layer. disposed on a surface on the inflow cell side in an inflow side region of the partition wall. When a gas permeability coefficient of an inflow side partition wall portion including the inflow side region of the partition wall and the inflow cell side catalyst layer is Ka and a gas permeability coefficient of an outflow side partition wall portion including an outflow side region at least from the predetermined position to an outflow side end of the partition wall is Kb, a ratio Ka/Kb of the gas permeability coefficients is within a range of 0.4 or more and 0.8 or less.

A honeycomb filter includes a pillar-shaped honeycomb structure body having a porous partition wall disposed to surround a plurality of cells and a plugging portion, wherein the partition wall is composed of a material containing cordierite as a main component thereof, porosity of the partition wall measured by a mercury press-in method is 60 to 68%, an average pore diameter of the partition wall measured by a mercury press-in method is 8 to 12 and in a pore diameter distribution which indicates a cumulative pore volume of the partition wall measured by a mercury press-in method, with a pore diameter (μm) on an abscissa axis and a log differential pore volume (cm.sup.3/g) on an ordinate axis, a first peak that includes a maximum value of the log differential pore volume has a pore diameter value of 10 μm or less, the pore diameter value corresponding to a ⅓ value width of the maximum value.

A honeycomb filter includes a pillar-shaped honeycomb structure body having a porous partition wall disposed to surround a plurality of cells and a plugging portion, wherein the partition wall is composed of a material containing cordierite as a main component thereof, porosity of the partition wall measured by a mercury press-in method is 60 to 68%, an average pore diameter of the partition wall measured by a mercury press-in method is 13 to 18 μm, and in a pore diameter distribution indicating a cumulative pore volume of the partition wall measured by a mercury press-in method, with a pore diameter (μm) on an abscissa axis and a log differential pore volume (cm.sup.3/g) on an ordinate axis, a first peak including a maximum value of the log differential pore volume has a pore diameter value of 15 μm or less, the pore diameter value corresponding to a ⅓ value width of the maximum value.

A honeycomb filter includes a pillar-shaped honeycomb structure body having a porous partition wall disposed, surrounding a plurality of cells which serve as fluid through channels extending from a first end face to a second end face; and a plugging portion provided at an open end on the first end face side or the second end face side of each of the cells, wherein the partition wall is composed of a material containing cordierite as a main component thereof, an average pore diameter of the partition wall is 20 to 30 μm, an average equivalent circle diameter of pores existing at a surface of the partition wall and having equivalent circle diameters exceeding 3.0 μm is 18 to 30 μm, and a number per unit area of pores existing at a surface of the partition wall and having equivalent circle diameters exceeding 3.0 μm is 400 per mm.sup.2 or more.

A honeycomb structure, including: a plurality of pillar shaped honeycomb segments, each of the pillar shaped honeycomb segments including a partition wall and a plugged portion; and a joining layer arranged so as to join side surfaces of the pillar shaped honeycomb segments to each other. The honeycomb structure satisfies the following equations (1) to (3):

y≤1000  (1);

y≤717.92x.sup.−0.095  (2); and

y≥462.4x.sup.−0.153  (3),

in which y is a maximum temperature (° C.) at which the use of the honeycomb structure is accepted, and x is a thermal conduction factor represented by the following equation:

thermal conduction factor=(thermal conductivity of the partition wall×thermal conductivity of the joining layer)/(average thickness of the joining layer×porosity of the partition wall).

A honeycomb body having intersecting porous walls which includes first through fourth cells, wherein the cells extend from inlet to outlet face and are plugged to define a repeating structural unit with three inlets and one outlet channel. Repeating structural unit includes a first channel including length L.sub.1, width W.sub.2, and area A.sub.1, a second channel including length L.sub.2, the width W.sub.2, and area A.sub.2, a third channel including the length L.sub.1, width W.sub.1, and area A.sub.3, and a fourth channel including the length L.sub.2, the width W.sub.1, and A.sub.4, wherein the first through third channels are inlets and the fourth channel is a rectangular outlet and at least one of W.sub.1≥W.sub.2 and L.sub.1≠L.sub.2, i.e. W.sub.1≥W.sub.2, or L.sub.1≠L.sub.2, or W.sub.1≥W.sub.2 and L.sub.1≠L.sub.2. Repeating structural unit has a quadrilateral outer perimeter. Particulate filters including the honeycomb body, honeycomb extrusion dies, and methods of manufacturing the honeycomb body are provided.

An inorganic membrane filtration article and methods for making the same. The membrane filtration article includes a sintered flow-through ceramic honeycomb with a plurality of partition walls defining a plurality of open channels from an inlet end of the honeycomb to an outlet end of the honeycomb. The honeycomb is formed from a cordierite composition with low-sodium and/or low-potassium content for enhanced filtration performance.

A filter for the filtration of a fluid, such as a liquid, includes or is composed of a support element made of a porous ceramic material, the element exhibiting a tubular or parallelepipedal shape delimited by an external surface and including, in its internal portion, a set of adjacent channels with axes parallel to one another and separated from one another by walls of the porous inorganic material, in which at least a portion of the channels and/or at least a portion of the external surface are covered with a porous separating membrane layer, wherein the separating membrane layer is made of a material essentially composed of silicon carbide (SiC), and the content by weight of elemental nitrogen of the layer constituting the porous separating membrane layer is between 0.1% and 2%.