A honeycomb structure includes a honeycomb segment bonded member including; a plurality of prismatic columnar shaped honeycomb segments; and a bonding layer bonding the segments, wherein one honeycomb segment has a bulge on one side face, extending in an axial direction, another honeycomb segment has a recess on one side face, extending in the axial direction, the one honeycomb segment and the another are disposed adjacent and bonded to each other via the bonding layer with the bulge inserted in the recess, length of the bulge is smaller than length of the one side face of the one honeycomb segment, length of the recess is smaller than length of the one side face of the another honeycomb segment, a base part of the bulge is defined with a bent side face, an angle between an imaginary bottom face and the bent side face of the bulge being 60° 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 filter includes a honeycomb structure body having porous partition walls defining a plurality of cells which become through channels for fluid, plugging portions disposed in open ends of the cells, and a protective layer disposed to cover at least the surface of the honeycomb structure body, each of the honeycomb structure body and the plugging portion has a structure constituted of aggregates made of silicon carbide and a bonding material which bonds the aggregates to one another, the protective layer is a layer in which silicon is present as much as 40 mass % or more and oxygen is present as much as 40 mass % or more and a thickness is 0.5 μm or more, and an outer end face of both end faces of the plugging portion has an exposed region in which the protective layer is not disposed.

A honeycomb structure including a plurality of porous honeycomb block bodies bound via joining material layers A. Each of the porous honeycomb block bodies includes a plurality of porous honeycomb segments bound via joining material layers B, each of the porous honeycomb segment includes: partition walls that defines a plurality of cells to form flow paths for a fluid, each of cells extending from an inflow end face that is an end face on a fluid inflow side to an outflow end face that is an end face on a fluid outflow side; and an outer peripheral wall located at the outermost periphery. At least a part of the joining material layers A has higher toughness than that of the joining material layers B.

A thermal shock resistant and asymmetric honeycomb ceramic wall-flow filter includes an inlet honeycomb ceramic surface and an outlet honeycomb ceramic surface. Inlet channels and outlet channels are provided on both the inlet honeycomb ceramic surface and the outlet honeycomb ceramic surface. The inlet channels are in communication with the outlet channels. Outlet ends of the inlet channels and inlet ends of the outlet channels are sealed. An inner diameter of the inlet channel is greater than that of the outlet channel. A cross-section of the inlet channel is a square, or two adjacent edges are connected by two connecting lines, or two adjacent edges are connected by two connecting lines or a circular arc located between the two connecting lines. The filter has good mechanical properties, low back pressure, and excellent thermal shock resistance.

A pillar shaped honeycomb structure including pillar shaped honeycomb segments joined together via joining material layers, wherein each of the pillar shaped honeycomb segment includes: an outer peripheral wall; and a porous partition wall disposed on an inner side of the outer peripheral wall, the partition wall defining a plurality of cells, each of the cells extending from one end face to other end face to form a flow path, and wherein a metal member is embedded in each of the joining material layer.

A honeycomb structure includes honeycomb segments, bonding layers and a circumferential wall. The bonding layers include bottomed-hollow voids which extend toward an internal side in an axial direction from an end face of the honeycomb structure and which are formed at at least one of intersections, and a ratio of a depth of each void in the axial direction to a length of each honeycomb segment in the axial direction is 5% or more.

A honeycomb structure includes a honeycomb segment bonded member including; a plurality of prismatic columnar shaped honeycomb segments; and a bonding layer bonding the segments, wherein one honeycomb segment has a bulge on one side face, extending in an axial direction, another honeycomb segment has a recess on one side face, extending in the axial direction, the one honeycomb segment and the another are disposed adjacent and bonded to each other via the bonding layer with the bulge inserted in the recess, length of the bulge is smaller than length of the one side face of the one honeycomb segment, length of the recess is smaller than length of the one side face of the another honeycomb segment, a base part of the bulge is defined with a bent side face, an angle between an imaginary bottom face and the bent side face of the bulge being 60° 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 plugged honeycomb structure, including: a plurality of honeycomb segments, a bonding layer and a circumferential wall disposed to surround circumference of a honeycomb segment bonded body where the plurality of honeycomb segments are bonded, wherein in the bonding layer, the bonding layer at a part that bonds the honeycomb segments disposed in contact with the circumferential wall is a circumferential bonding layer, and the bonding layer at a part that bonds the honeycomb segment including a center of gravity in a cross section orthogonal to the extending direction of cells of the honeycomb segment bonded body or at a position closest to the center of gravity and another honeycomb segment adjacent to the honeycomb segment is a center bonding layer, and a bonding strength A1 of the circumferential bonding layer is larger than a bonding strength A2 of the center bonding layer.