A method and extrusion die to form a laminar integral skin of a honeycomb structure is provided. The method includes extruding a ceramic precursor batch through a die with feedholes in entry side and slots in exit face of the die to form the honeycomb structure. In a region on the periphery of the die configured to form the cell matrix, a series of concentric slots around the matrix in the exit face of the die are configured to feed skin onto the matrix. Ring sections between concentric slots are angled away from the center and a mask is disposed on top of the periphery producing a channel for extruded skin to meet and bond to extruded matrix. Optionally, slots in the skin-forming ring sections enhance knitting between laminar skin layers.

A pillar shaped honeycomb structure includes: a porous partition wall that defines a plurality of cells, the cells forming flow paths for a fluid, the cells extending from an inflow end face to an outflow end face; and an outer peripheral wall located at the outermost circumference. The cells include: a plurality of cells A wherein a side of the inflow end face is opened and the outflow end face has a plugged portion; and a plurality of cells B wherein a side of the outflow end face is opened and the inflow end face has a plugged portion, the cells B being arranged alternately with the cells A. One or both of the plugged portion of the cells A and the plugged portions of the cells B contain a magnetic substance and glass.

A ceramic honeycomb filter has (a) cross section areas of intake flow paths being larger than those of discharge flow paths; (b) the intake and discharge flow paths having octagonal cross section shapes with four-fold rotation symmetry each obtained by cutting off four corners from a square; (c) the intake and discharge flow paths being alternately arranged in a first direction and a second direction perpendicular to the first direction, such that their opposing sides are parallel; (d) the opening ratio of the intake flow paths being 45-60%; (e) the number of the flow paths per cm.sup.2 being 30-60; (f) the thickness t1 of a cell wall between an intake flow path and a discharge flow path adjacent to that intake flow path being 0.150-0.260 mm; and (g) the thickness t2 of a cell wall between adjacent intake flow paths meeting 1.175<t2/t1<1.6.

A honeycomb structure has a plurality of cells formed by a plurality of partition walls. The partition walls are formed of a porous material composed predominantly of cordierite. Each partition wall includes surface layer portions having a porosity of 50% or more and an inside portion having a porosity of 50% or more, the surface layer portions being portions ranging respectively from opposite surfaces to a depth corresponding to 25% of the thickness of the partition wall, and the inside portion being the other portion. The surface layer portions and the inside portion both include pores having axial pore widths of less than 30 μm and pores having axial pore widths of 30 μm or more. A mean axial pore width in the surface layer portions is smaller than a mean axial pore width in the inside portion.

Ceramic honeycomb bodies and methods for then manufacture are provided. The ceramic honeycomb body comprises a bulk density of less than 210 g/L, a geometric surface area (GSA) greater than 93 in.sup.−1 (3.66 mm.sup.−1), a mechanical integrity factor (MIF) greater than 0.28%, and a back pressure factor (BPF) greater than 0.4 mm.sup.2.

A honeycomb structure including: a honeycomb structure body having porous partition walls which define a plurality of cells extending from an inflow end face to an outflow end face to form through channels for a fluid, and a first circumferential wall which is disposed in at least a part of a circumference of the partition walls, and a second circumferential wall disposed to surround an outer side of the honeycomb structure body, wherein the honeycomb structure body does not have an interface between the partition walls and the first circumferential wall, and in a face perpendicular to an extending direction of the cells, a maximum thickness of the first circumferential wall is from 0.1 to 0.3 mm.

A ceramic honeycomb structure having a web structure including a plurality of intersecting channel walls forming channels. The ceramic honeycomb structure has a total porosity greater than or equal to about 55%, an average channel wall thickness less than or equal to about 150 μm, a median pore diameter greater than or equal to about 10 μm, a d.sub.f less than or equal to about 0.45, where d.sub.f=(d.sub.50−d.sub.10)/d.sub.50, and a strength (MOR/CFA) greater than or equal to about 900 psi. A method of manufacturing a ceramic honeycomb structure by mixing a ceramic precursor batch composition having a median particle diameter less than or equal to about 10 μm and at least one starch-based pore former having a median particle diameter greater than or equal to about 10 μm. The method also includes forming a mixture of ceramic precursor batch composition and a starch-based pore former into a green ceramic structure having a web structure, and firing the green ceramic structure to yield a ceramic honeycomb structure.

The present disclosure relates to porous ceramic materials and porous ceramic articles, including honeycomb structure bodies and porous ceramic filters comprised of plugged honeycomb bodies. In various embodiments, a particulate filter is disclosed herein, such as suitable as a gasoline particulate filter (GPF) for use with a gasoline engine and treating its exhaust, and/or such as a diesel particulate filter (DPF) suitable for use with a diesel engine and treating its exhaust.

A honeycomb structure (110) includes intersecting porous walls (106). Inlet channels (108i) and outlet channels (108o) are formed by the intersecting porous walls (106), wherein the inlet channels (108i) comprise inlet hydraulic diameters (HDi) and the outlet channels (108o) comprise outlet hydraulic diameters (HDo). The inlet channels (108i) comprise inlet corners (220i) with inlet corner radii (Ri) and the outlet channels (108o) comprise outlet corners (2200) with outlet corner radii (Ro). A centerpost (124) is defined by adjacent opposing inlet corners (220i) of two of the inlet channels (108i) and adjacent opposing outlet corners (2200) of two of the outlet channels (108o). A first diagonal length (D1) is a shortest distance between the opposing outlet corners (220o) of the two outlet channels (108o) and a second diagonal length (D2) is a shortest distance between the opposing inlet corners (220i) of the two inlet channels (108i). The honeycomb structure (110) has certain aspect ratios D1:D2 depending on hydraulic diameter ratios HDi:HDo.

A honeycomb structure including a honeycomb portion having porous partition walls extending from an inflow end face to an outflow end face, an outermost peripheral wall, and a pair of electrode layers on a side surface of the honeycomb portion. Each electrode layer extends in a direction of the cells. One electrode layer is disposed on a side opposite to the other electrode layer across a center of the honeycomb portion in a cross section orthogonal to the extending direction of the cells. The honeycomb structure portion includes first cells opened on the inflow side and plugged on the outflow side, and second cells opened on the outflow side and plugged on the inflow side. A middle of each length of the pair of electrode layers is closer to the outflow side than a middle position of a length of the honeycomb portion in the extending direction of the cells.