Patent ID: 8518855

Claim:
A honeycomb structure comprising: aluminum titanate; cell walls extending along a longitudinal direction of the honeycomb structure to define cells between the cell walls; pore portions having an average pore diameter of about 10 μm to about 20 μm; and a length of a longest pore portion among the pore portions in a binary image comprising substrate portions and the pore portions being about 8 times or less of the average pore diameter, wherein the binary image is converted from a microscopic image of a cross section of the cell walls in parallel with the longitudinal direction, and wherein the length is measured along a line drawn in a direction perpendicular to a thickness direction of the cell walls, and wherein the honeycomb structure is produced by using a mixture including a pore-forming agent having a particle-distribution index of 1.8-2.0, where the particle-distribution index is calculated as being equal to (D90-D10)/D50, where D90 is a 90% particle diameter, D50 is a 50% particle diameter, and D10 is a 10% particle diameter.