초록 ▼

A glass composition is disclosed which has a high modulus of elasticity and a low density, i.e., has a high specific modulus. Also disclosed is an inexpensive glass composition which is suitable for use as an information recording medium substrate, for example, because it can be formed easily, is le

A glass composition is disclosed which has a high modulus of elasticity and a low density, i.e., has a high specific modulus. Also disclosed is an inexpensive glass composition which is suitable for use as an information recording medium substrate, for example, because it can be formed easily, is less apt to suffer devitrification, is suitable for mass production, and can be easily made to have high surface smoothness by polishing. The glass compositions comprise, in terms of mol %, 35 to 45% silicon dioxide (SiO2), 15 to 20% aluminum oxide (Al2O3), 3 to 10% lithium oxide (Li2O), 0.1 to 5% sodium oxide (Na2O), 15 to 30% magnesium oxide (MgO), 0 to 10% calcium oxide (CaO), 0 to 4% strontium oxide (SrO), 25 to 35% RO (MgO+CaO+SrO), 2 to 10% titanium dioxide (TiO2), 0.5 to 4% zirconium oxide (ZrO2), 4 to 12% TiO2+ZrO2, and 0 to 4% yttrium oxide (Y2O3).

대표청구항 ▼

1. A glass composition comprising, in terms of mol %,35 to 45% silicon dioxide (SiO2), 15 to 20% aluminum oxide (Al2O3), 3 to 10% lithium oxide (Li2O), 0.1 to 5% sodium oxide (Na2O), 15 to 30% magnesium oxide (MgO), 0 to 10% calcium oxide (CaO), 0 to 4% strontium oxide (SrO), 25 to 35% RO (MgO+CaO+S

1. A glass composition comprising, in terms of mol %,35 to 45% silicon dioxide (SiO2), 15 to 20% aluminum oxide (Al2O3), 3 to 10% lithium oxide (Li2O), 0.1 to 5% sodium oxide (Na2O), 15 to 30% magnesium oxide (MgO), 0 to 10% calcium oxide (CaO), 0 to 4% strontium oxide (SrO), 25 to 35% RO (MgO+CaO+SrO), 2 to 10% titanium dioxide (TiO2), 0.5 to 4% zirconium oxide (ZrO2), 4 to 12% TiO2+ZrO2, and 0 to 4% yttrium oxide (Y2O3).