High specific elasticity moduli aluminosilicate glasses or glass-ceramics, for hard disk substrates, contain boron, alkali and alkaline earth metal, magnesium, phosphorus and titanium oxides

摘要

High specific elasticity moduli aluminosilicate glasses or glass-ceramics, having specified boron, alkali and alkaline earth metal, magnesium, phosphorus and titanium oxide contents, are new Novel glasses or glass-ceramics, with high specific elasticity moduli, have the composition (by wt., on oxide basis) 25-50% SiO2, greater than 5-16% B2O3, 10-17% Al2O3, 0-8% P2O5, 5-15% Li2O, 0-10% Na2O, 0-10% K2O, 10-30% MgO, 0-10% CaO, 0-8% SrO, 0-8% ZnO, 0.1-10% TiO2, 0-8% ZrO2 and optionally usual amounts of refiners, the sum of alkali metal oxides being = 30% and the sum of alkaline earth metal oxides being = 45%.