Sodium aluminosilicate glass article strengthened by a surface compressive stress layer
Abstract
Abstract IMPROVED GLASS COMPOSITIONS ARE DESCRIBED FOR A SODIUM ALUMINOSILICATE GLASS ARTICLE HAVING A SURFACE COMPRESSIVE STRESS LAYER THAT STRENGTHENS THE ARTICLE. THE SURFACE COMPRESSIVE STRESS LAYER IS CHEMICALLY DEVELOPED BY AN ION EXCHANGE IN WHICH A RELATIVELY LARGE MONOVALENT ION IS INTRODUCED INTO THE SURFACE OF THE GLASS ARTICLE IN EXCHANGE FOR THE SODIUM ION AT A TEMPERATURE BELOW THE STRAIN POINT OF THE GLASS. THE IMPROVED COMPOSITIONS PROVIDE GLASSES HAVING UNUSUAL LIQUIDUS CHARACTERISTICS, AND CONSIST ESSENTIALLY, ON AN OXIDE BASIS IN MOLE PERCENT, OF 5-25% NA2O, 1-5% MGO, AN AMOUNT OF ZRO2 EFFECTIVE TO IMPROVE CHEMCIAL DURABILITY OF THE STRENGTHENED GLASS BUT NOT OVER 3%, AT LEAST 8% AL2O2, THE TOTAL ZRO2 PLUS AL2O2 BEING NOT OVER 13.5% AND THE BALANCE ESSENTIALLY SILICA.
Inventors
- 👤 D Boyd
Bibliographic Details
Claims Analysis
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