A ceramic body mainly based on BaTiO.sub.3-based crystalline particles in which a part of Ba is substituted with at least one rare earth element and at least one alkaline earth metal element. The ceramic body contains from 1.0 to 8.0% by mass of Ba.sub.6Ti.sub.17O.sub.40 crystalline particles. The BaTiO.sub.3-based crystal particles have a substituted amount of one mol of the Ba with the alkaline earth metal element of 0.01 to 0.10 mol.

An electric heating type support includes: an electrically conductive honeycomb structure including a pillar shaped honeycomb structure portion composed of conductive ceramics, the pillar shaped honeycomb structure portion including: an outer peripheral wall; and porous partition walls disposed on an inner side of the outer peripheral wall, the porous partition walls defining a plurality of cells, each cell penetrating from one end face to other end face to form a flow path; and a pair of metal terminals disposed so as to face each other across a central axis of the pillar shaped honeycomb structure portion, each metal terminal being joined to a surface of the electrically conductive honeycomb structure via a welded portion so as to follow a surface shape of the electrically conductive honeycomb structure.

An electric resistor includes a particle continuous body in which a plurality of conductive particles are connected, and a matrix disposed around the particle continuous body. The particle continuous body has surface-joined portions in which surfaces of the conductive particles are joined to each other. Silicon particles are preferably used as the conductive particles. The average boundary line length of the surface-joined portions is preferably 0.5 μm or more.

An electrical heater and method for heating a catalyst. The heater includes a honeycomb body having intersecting walls forming channels extending along a longitudinal axis. A plurality of electrically resistive paths are included, each including at least a portion of the plurality of intersecting walls and extending a length across the honeycomb body transverse to the longitudinal axis. A positive electrode and a negative electrode are in electrical communication with each other via the resistive paths. The positive electrode and the negative electrode are operatively positioned to generate a respective flow of current through each resistive path. The lengths of at least two of the resistive paths differ from each other. The resistive paths are configured with respect to the at least one positive electrode and the at least one negative electrode such that the current in each of the resistive paths is substantially equal.

A heating element and heating assembly to heat a fluid as part of a heating device. The heating element is formed from a high electrical resistance material such as an FeCrAl based material. The heating device comprises a heating block having a high heating-surface area to volume ratio (HTVR) to achieve a high heating density with a low surface load.

A heater element includes: a honeycomb structure having an outer peripheral wall and partition walls disposed on an inner side of the outer peripheral wall, the partition walls defining a plurality of cells each forming a flow path from a first end face to a second end face, the outer peripheral wall and the partition walls made of a material having a PTC property; and a pair of electrode layers provided on a surface of the outer peripheral wall. The honeycomb structure has a shape having a long axis and a short axis in a cross section orthogonal to a central axis.

A heater element for heating a vehicle interior includes: a honeycomb structure comprising: an outer peripheral wall; and a partition wall disposed on an inner side of the outer peripheral wall, the partition wall defining a plurality of cells each forming a flow path from a first end face to a second end face, the outer peripheral wall and the partition wall comprising a material having a PTC property; and a pair of electrodes provided on the first end face and the second end face. Each of the first end face and the second end face of the honeycomb structure is rectangular. The heater element for heating the vehicle interior further includes a pair of connectors, each of the connectors being connected to the electrode from one short side of each of the first end face and the second end face.

A honeycomb structure including a honeycomb portion having porous partition walls extending from an inflow end face to an outflow end face to define cells forming through channels, an outermost peripheral wall, and a pair of electrode portions disposed on a side surface of the honeycomb portion. The electrode portions are formed in a strip shape extending in a direction of the cells. In a cross section orthogonal to the extending direction, one electrode portion of the pair of electrode portions is disposed on a side opposed to the other electrode portion across a center of the honeycomb structure portion. The honeycomb structure portion includes end regions near the pair of electrode portions and a central region excluding the end regions. An average electric resistivity A of a material forming the end regions is lower than an average electric resistivity B of a material forming the central region.

A method for producing a ceramic honeycomb structure, the honeycomb structure includes: an outer peripheral wall; and partition walls disposed on an inner side of the outer peripheral wall, the partition walls defining a plurality of cells, each of the cells extending from one end face to the other end face to form a flow path, wherein the honeycomb structure includes at least one slit provided on a cross section perpendicular to an axial direction of the honeycomb structure, wherein the method includes the steps of: preparing a honeycomb structure element before forming the slit; and forming the slit by arranging a wire so as to pass from one end face to the other end face in the cell and then cutting the partition walls while moving the honeycomb structure element and/or the wire.

A conductive honeycomb structure that is divided into four equal portions in a flow path direction of cells in the structure to form four regions of A, B, C, and D from a side closer to a first end face, and an average value of electric resistances measured between two points in each of the four regions is represented as R.sub.A, R.sub.B, R.sub.C, and R.sub.D in this order from the side closer to the first end face. A relational expression of R.sub.A≤R.sub.B≤R.sub.C≤R.sub.D (excluding R.sub.A=R.sub.B=R.sub.C=R.sub.D) is satisfied provided that the two points being determined so that a distance between a pair of electrode layers arranged on an outer peripheral side wall of the structure is the longest in the cross section perpendicular to the flow path direction of the cells.