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 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 honeycomb structure includes a honeycomb structure body having a partition wall which is constituted of a porous body. The porous body includes a refractory aggregate and a bonding material. The porous body constituting includes the bonding material at a mass proportion of 20 to 35 mass %. In an observation of a cross section of the partition wall with an electron microscope, when observing any given ten visual fields meeting a following condition (1), the number of refractory aggregates meeting a following condition (2) is five pieces or more in all of the ten visual fields. Condition (1): a proportion of an area occupied by the bonding material is 30% or more. Condition (2): the refractory aggregate has a particle diameter of 5 μm or more, and 60% or more of an outer circumference of the refractory aggregate is surrounded by the bonding material.

A honeycomb structure includes a honeycomb structure body having a partition wall which is constituted of a porous body. The porous body includes a refractory aggregate and a bonding material. The porous body constituting includes the bonding material at a mass proportion of 20 to 35 mass %. In an observation of a cross section of the partition wall with an electron microscope, when observing any given ten visual fields meeting a following condition (1), the number of refractory aggregates meeting a following condition (2) is five pieces or more in all of the ten visual fields. Condition (1): a proportion of an area occupied by the bonding material is 30% or more. Condition (2): the refractory aggregate has a particle diameter of 5 μm or more, and 60% or more of an outer circumference of the refractory aggregate is surrounded by the bonding material.

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 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 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 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 joining material used for joining side surfaces of a plurality of silicon carbide-based honeycomb segments to each other to produce a silicon carbide-based honeycomb structure. The joining material contains from 0.1 to 50% by mass of processed powder generated in the production of the silicon carbide-based honeycomb segments and/or the silicon carbide-based honeycomb structure. The joining material has an average particle diameter D50 of from 0.5 to 60 μm.