Patent ID: 7037870

Claim:
A ceramic sintered body comprising from 92 to 99.5% by volume of cordierite and from 0.5 to 8% by volume of mullite based on 100% by weight of a total sum of the contents of the cordierite and the mullite, wherein the crystal phase of said sintered body detected by x-ray diffraction measurements consists only of a cordierite phase and a mullite phase including inevitable impurities, and having a density of 2.48 g/cm 3 or more, wherein the cordierite crystal has a mean particle size of 2 μm or less, and wherein said ceramic sintered body has a thermal expansion coefficient, as measured at 20 to 25° C., of from −0.03 to 0.16 ppm/K and a value, as obtained by dividing a Young's modulus by the density, of 54.7 to 56.5 Gpa/g/cm 3 or more.