GLASS CERAMIC AND METHOD FOR MANUFACTURE THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a luecite crystal-containing glass ceramic hardly causing the reduction of coefficient of thermal expansion and the emulsification of the glass ceramic during the welding work to a metallic crown. SOLUTION: The luecite crystal-containing glass ceramic contains the luecite crystal and the coefficient of thermal expansion at 50-500 deg.C is (12-17.5)×10-6/ deg.C, and the precipitation of Na.K feldspar crystal is not caused after heating at 850 deg.C for 3 hr.