Alkali-free alumino:borosilicate glass

摘要

Alkali-free aluminoborosilicate glass has a viscosity of 10<13> dPas at above 700 deg C, a working temperature of less than 1220 deg C and very good chemical resistance, can be produced in a float unit and has the composition (by wt., on oxide basis) 48 to less than 55 (preferably 49-53)% SiO2, 7-15 (preferably 9-13)% B2O3, more than 20 to 26 (preferably more than 20 to 24)% Al2O3, 0-8 (preferably 0-6)% MgO, 4-12 (preferably 6-11)% CaO, 0-2 (preferably 0-1)% BaO, 0-2 (preferably 0-1)% SrO, 1-8 (preferably 2-6)% ZnO, 0-2% ZrO2 and 0.52 (preferably 0.5-1.5)% SnO2.