Alkali-free glass substrate
First Claim
1. An alkali-free glass substrate consisting essentially of, by weight, 58.0-68.0% SiO2, 10.0-25.0% Al2 O3, 3.0-15.0% B2 O3, 0-2.9% MgO, 0-8.0% CaO, 0.1-5.0% BaO, 0.1-10.0% SrO, 0-5.0% ZnO, 5.0-20.0% MgO+CaO+SrO+BaO+ZnO, 0-5.0% ZrO2, and 0-5.0% TiO2, said substrate being essentially free of alkali metal oxide, having a density not exceeding 2.55 g/cm3, and a chemical resistance so that the glass surface does not change after the glass is immersed for 30 minutes in a buffered hydrofluoric acid solution held at 20°
- C., said buffered hydrofluoric acid solution comprising, by weight, 38.7% ammonium fluoride and 1.6% hydrofluoric acid.
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Abstract
In order to provide an alkali-free glass substrate which contains substantially no alkali metal oxide, which has chemical resistance, a high strain point, excellent meltability, and devitrification resistance, the alkali-free glass substrate contains substantially no alkali metal oxide and essentially consists, by weight, of 58.0-68.0% SiO2, 10.0-25.0% Al2 O3, 3.0-15.0% B2 O3, 0-2.9% MgO, 0-8.0% CaO, 0.1-5.0% BaO, 0.1-10.0% SrO, 0-5.0% ZnO, 0-5.0% ZrO2, and 0-5.0% TiO2.
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1 Claim
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1. An alkali-free glass substrate consisting essentially of, by weight, 58.0-68.0% SiO2, 10.0-25.0% Al2 O3, 3.0-15.0% B2 O3, 0-2.9% MgO, 0-8.0% CaO, 0.1-5.0% BaO, 0.1-10.0% SrO, 0-5.0% ZnO, 5.0-20.0% MgO+CaO+SrO+BaO+ZnO, 0-5.0% ZrO2, and 0-5.0% TiO2, said substrate being essentially free of alkali metal oxide, having a density not exceeding 2.55 g/cm3, and a chemical resistance so that the glass surface does not change after the glass is immersed for 30 minutes in a buffered hydrofluoric acid solution held at 20°
- C., said buffered hydrofluoric acid solution comprising, by weight, 38.7% ammonium fluoride and 1.6% hydrofluoric acid.
Specification