A filter comprising a columnar honeycomb structure part, the columnar honeycomb structure part including: a plurality of first cells each extending from a first bottom surface to a second bottom surface of the columnar honeycomb structure part, the first bottom surface being opened and the second bottom surface being plugged for the plurality of first cells; a plurality of second cells each extending from the first bottom surface to the second bottom surface of the columnar honeycomb structure part, the first bottom surface being plugged and the second bottom surface being opened for the plurality of second cells; and porous cordierite partition walls that define the first cells and the second cells, the partition walls having an average pore depth of 1.5 m or more and 3.5 m or less as measured by a laser microscope, and a porosity of from 50 to 60% as measured by a mercury porosimeter.

Disclosed is a honeycomb filter for collecting fine particles that includes a wall portion formed from a base material containing ceria-zirconia composite oxide and an inorganic binder. In a pore diameter distribution in which a pore diameter and a log differential pore volume measured through mercury porosimetry are respectively represented by a horizontal axis and a vertical axis, the wall portion has a peak in a range in which the pore diameter is greater than or equal to 0.01 m and less than 1 m and a peak in a range in which the pore diameter is greater than or equal to 1 m and less than or equal to 50 m.

A honeycomb filter includes a pillar-shaped honeycomb structure body having a porous partition wall surrounding cells each of which has one end plugged by a plugging portion. An open frontal area O (%) of the cells in the honeycomb structure body is 75 to 80%, a porosity P (%) of the partition wall measured by a mercury press-in method is 52 to 58%, an average pore diameter D (m) of the partition wall measured by the mercury press-in method is 6 to 12 m, and a pore volume rate A (%) of pores whose pore diameters are not less than 20 m with respect to an overall pore volume of the partition wall is not more than 13.5%.

A honeycomb filter includes a honeycomb structure body having porous partition walls arranged to surround cells, in a cross section of the honeycomb structure body which is perpendicular to an extending direction of the cells, a value of a porosity of the partition wall in a partitioning region between the inflow cell and the outflow cell is defined as a porosity A, among intersecting portions where partitioning regions of the partition walls between the cells intersect one another, a value of a porosity of the partition wall in an intersecting portion between the two inflow cells is defined as a porosity B, and a value of A/B obtained by dividing the porosity A by the porosity B is from 0.50 to 0.95.

An exhaust gas purification filter that suppresses an increase in pressure loss associated with the formation of a catalyst layer and is excellent in PM burning quality. The exhaust gas purification filter includes a base and a catalyst layer provided on the base. The catalyst layer contains a carrier and a metal catalyst. Large pores having a circle equivalent diameter greater than 5 m occupy, when an area of the catalyst layer is 100% in an electron microscope observation image of a cross section of the catalyst layer, 45% or more of the area.

The present disclosure relates to porous ceramic articles and a method of making the same. The porous ceramic articles have a porosity (P) as a fraction in a range of about 0.3 to about 0.7; a permeability factor PQ>0.025, wherein PQ is (K.sub.bulk)/(P.Math.d.sub.50.sup.2), K.sub.bulk being bulk permeability in Darcy, and d.sub.50 being the mean pore size in micrometers (m); a tortuosity in a range of about 1.8 to 3; and a median pore size diameter d.sub.50 in a range of about 10 m to about 35 m. The porous ceramic articles can have an interconnected bead microstructure comprising beads and bead connections, PQ is directly proportional to bead size, and wherein in a random cross section through the body, the beads appear as globular portions.

A honeycomb filter includes a pillar-shaped honeycomb structure having porous partition walls provided, surrounding a plurality of cells which serve as fluid through channels extending from an inflow end face to an outflow end face, and porous plugging portions provided either at the ends on the inflow end face side or the outflow end face side of the cells, wherein the plugging portions are composed of a porous material, the honeycomb structure has a central region and a circumferential region, and a ratio of an area of the circumferential region with respect to that of the central region ranges from 0.1 to 0.5, porosity of a central plugging portion in the central region, is higher than that of a circumferential plugging portion in the circumferential region, and the porosity of the central plugging portion ranges from 76% to 85%, and that of the circumferential plugging portion from 60% to 75%.

A honeycomb filter includes a pillar-shaped honeycomb structure having porous partition walls placed, surrounding a plurality of cells which serve as fluid through channels extending from an inflow end face to an outflow end face; and porous plugging portions provided either at the ends on the inflow end face side of the cells or at the ends on the outflow end face side of the cells, wherein the plugging portions include plugging portions that have voids therein, and in the plugging portions having the voids, porosity including the voids as pores ranges from 68% to 83%.

A particulate filter, including: a pillar-shaped honeycomb structure portion having a plurality of first cells extending from a first end face to a second end face, the first end face being open and the second end face being plugged, and a plurality of second cells extending from the first end face to the second end face, the first end face being plugged and the second end face being open, in which the first cells and the second cells are alternately arranged adjacent to each other with porous partition walls interposed therebetween; and a low thermal conductive layer covering a part or the whole of an outer peripheral side surface of the pillar-shaped honeycomb structure portion, the thermal conductivity in a thickness direction of the low thermal conductive layer being 0.6 W/(m.Math.K) or less.

A honeycomb filter includes a pillar-shaped honeycomb structure having porous partition walls provided, surrounding a plurality of cells which serve as fluid through channels extending from an inflow end face to an outflow end face, and a porous plugging portion provided either at an end on the inflow end face or the outflow end face of the cells, wherein the plugging portion is composed of a porous material, the honeycomb structure has a central region and a circumferential region, and a ratio of an area of the circumferential region with respect to that of the central region ranges from 0.1 to 0.5, porosity of a central plugging portion in the central region is lower than that of a circumferential plugging portion in the circumferential region, and the porosity of the central plugging portions ranges from 60% to 68%, and that of the circumferential plugging portions ranges from 70% to 85%.