Glasses, thermally stable high (beta)-cristobalite glass-ceramics and method

Abstract

Thermally stable high (beta)-cristobalite glass-ceramics suitable for making articles such as refractory linings for ovens, furnaces, and the like and which do not undergo transition to the low (alpha)-cristobalite crystal phases upon cooling of the ceramic to ambient temperature. A method for making such stable ceramics by melting a glass of the composition MO. Al.sub.2 O.sub.3.nSiO.sub.2 wherein the Al.sub.2 O.sub.3 MO molar ratio is 1, MO is CaO or a mixture of CaO and MxO where Mx is a cation of the first, second or fourth group of the Periodic Table or iron and n is a positive number of from 8 to 37, and subjecting the glass to a heat schedule sufficient to form a stabilized high (beta)-cristobalite type crystal structure in the resulting glass-ceramic, with or without a portion of low cristobalite and/or feldspar crystals.

Dependencies are inferred from the claim text.