ALKALI-FREE ALUMINOBOROSILICATE GLASS, ITS USE AND PROCESS OF PRODUCTION

摘要

Alkali-free alumino-borosilicate glass contains (in wt.%): 60-65 SiO2, 6.5-9.5 B2O3, 14-21 Al2O3, 1-8 MgO, 1-6 CaO, 1-9 SrO, 0.1-0.35 BaO, 8-16 MgO + CaO + SrO + BaO, 0.1-1.5 ZrO2, 0.1-1 SnO2, 0.1-1 TiO2 and 0.01-1 CeO2. An Independent claim is also included for a process for the production of the alkali-free alumino-borosilicate glass comprising adding 0.2-3 wt.% NH4NO3 to the starting materials, melting, plaining, homogenizing and hot molding. Preferred Composition: Alkali-free alumino-borosilicate glass contains (in wt.%): 60.5-65.0 SiO2, 6.5-9.0 B2O3, 15-20 Al2O3, 1-7 MgO, 1-5 CaO, 2-8 SrO, 0.5-0.3 BaO, 9-15 MgO + CaO + SrO + BaO, 0.2-1 ZrO2, 0.2-0.8 SnO2, 0.1-0.5 TiO2 and 0.01-0.5 CeO2.