Patent ID: 7476633
Filing Date: 2009-01-13
Classification: C03C

Abstract:
1. A glass-ceramic material having β-spodumene solid solution as the predominant crystalline phase, a CTE from about 25 to about 700° C. of about 10-30×10 −7 /° C., and a composition, by weight of the total composition, comprising: 55-68% SiO 18-24% Al 3.3-4.1% Li 1.5-4.0% ZnO; 1.5-5.0% MgO; 2-5% TiO 0-2% ZrO 0-5% B 0-8% P 0-2% Na 0-2% K 0-0.1% As 0-0.1% Sb components resulting from effective amount of at least one fining agent, wherein: the total of B the total of MgO and ZnO is at least about 3.5% by weight, the total of Na the total of P the weight ratio of the sum total of Na is less than about 0.5.