Patent ID: 8481454

Claim:
A honeycomb structure comprising: aluminum titanate; cell walls extending along a longitudinal direction of the honeycomb structure to form a plurality of cells between the cell walls; a porosity from about 40% to about 60%; and in a binary image of substrate portions and pore portions of each of the cell walls, an area ratio (%) of the pore portions to a whole area in a rectangularly-divided image is in a range from (the porosity−about 25%) to (the porosity+about 25%), wherein said binary image is converted from a microscopic image of a cross section of each of the cell walls in parallel with the longitudinal direction, and said rectangularly-divided image is formed by dividing the binary image in a direction parallel to a thickness direction of each of the cell walls at a predetermined width, and wherein the honeycomb structure is produced by using a mixture including a coarse powder of aluminum titanate having a particle-distribution index of 1.5-2.0, and a pore-forming agent having a particle-distribution index of 1.4-1.8, where the particle-distribution indices are 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.