Patent ID: 6265334
Filing Date: 2001-07-24
Classification: C04B,H01L

Abstract:
Low thermal expansion ceramics comprising:a cordierite crystal phase; anda crystalline compound phase precipitated in grain boundaries of the cordierite phase comprising (M.sup.1).sub.2 Si.sub.2 O.sub.7 or (M.sup.2)Si2Al.sub.2 O.sub.3, wherein M1 is an element selected from the group consisting of rare earth elements, Ga and In, wherein M2 is an alkaline earth element other than Mg, wherein when the element is a rare earth element, the element is contained in an amount of 1-20% by weight in terms of an oxide thereof, and when the element is Ga, In or an alkaline earth element other than Mg, the element is contained in an amount of 0.5%-10% by weight in terms of an oxide thereof, and wherein the ceramics have a relative density of not less than 95%, a coefficient of thermal expansion of not larger than 1.times.10.sup.-6 /.degree. C. at 10 to 40.degree. C., and a Young's modulus of not less than 130 Gpa.