Patent ID: 8691361

Claim:
A ceramic honeycomb structure having a large number of flow paths defined by porous cell walls having porosity of 45-68% and an average pore size of 15-35 μm, said ceramic honeycomb structure having a thermal expansion coefficient of 3 ×10 −7 /° C. to 13 ×10 −7 /° C. between 20° C. and 800° C., and pores meeting the following conditions: the volume of pores having diameters of more than 50 μm being more than 10% and 25% or less of the total pore volume; the volume of pores having diameters of 100 μm or more being 1-8% of the total pore volume; the volume of pores having diameters of less than 10 μm being 3-10% of the total pore volume; and said pores having a pore size distribution deviation σ[=log(D 20 )−log(D 80 )] of 0.45 or less, wherein D 20 represents a pore size (μm) at a pore volume corresponding to 20% of the total pore volume, and D 80 represents a pore size (μm) at a pore volume corresponding to 80% of the total pore volume, in a curve showing the relation between a pore size and a cumulative pore volume obtained by accumulating a pore volume from the maximum pore size to a particular pore size, and D 80 <D 20 .