Glass-ceramic article and method
Abstract
Abstract THIS INVENTION RELATES TO THE STRENGTHENING OF GLASSCERAMIC ARTICLES IN WHICH THE CRYSTAL CONTENT THEREOF COMPRISES THE PREDOMINANT PART OF THE ARTICLES AND CONTAINING BETA-QUARTZ STUFFED WITH MAGNESIUM IONS AS THE PRIMARY CRYSTAL PHASE. THE STRENGTHENING IS SECURED THROUGH CONSECUTIVE ION EXCHANGE REACTIONS WHEREIN LITHIUM IONS FROM AN EXTERNAL SOURCE ARE FIRST EXCHANGED FOR MAGNESIUM IONS IN THE BETA-QUATRZ WITHIN A SURFACE LAYER ON THE ARTICLE AND THEREAFTER SODIUM AND/OR POTASSIUM IONS FROM AN EXTERNAL SOURCE ARE EXCHANGED FOR THE LITHIUM IONS DIFFUSED INTO THE STRUCTURE OF THE BETA-QUARTZ DURING THE FIRST EXCHANGE. THIS CONSECUTIVE ION EXCHANGE DOES NOT ALTER THE ESSENTIAL STRUCTURAL NATURE OF THE BETA-QUARTZ CRYSTALS BUT DOES CAUSE COMPRESSIVE STRESSES TO BE DEVELOPED IN THE SURFACE LAYER.
Inventors
- 👤 Hermann L Rittler
Bibliographic Details
Claims Analysis
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