Lithium-aluminium-silicate glass with short ceramisation time

摘要

Lithium aluminosilicate glass has a ceramicisation time below 2.5 hours and converts into a transparent glass ceramic with a beta-quartz structure as main crystal phase. It has a cloudiness below 1% according to ASTM D1003 and a neutral color. It has the following composition (wt% of oxide): SnO 2 0 - 0.4; SnO 2 + TiO 2 1.3 = 2.7; ZrO 2 1.3 - 2.5; ZrO 2 + 0.87(TiO 2 + SnO 2); Fe 2O 3 not more than 0.04; Nd 2 O 3 0.005 - 0.4; and CoO 0 - 0.005. Independent claims are included for: (a) glass ceramics produced from the lithium aluminosilicate glass; and (b) transparent glass ceramics produced from the lithium aluminosilicate glass with Nd 2O 3 content below, CoO content below 20 ppm, a thermal expansion coefficient alpha 20/700 of 0 +- 0.5.10 -6>/K, especially 0 +- 0.3.10 -6>/K, light transmission for a 4 mm thick sample above 80% and a tint according to the CIELAB color system below 3.5.