Transparent forsterite glass-ceramics
AssigneeCorning Incorporated
InventorGeorge H. Beall
Life of this patent
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Abstract
A glass-ceramic which is substantially and desirably totally transparent, and which contains a predominant crystal phase of forsterite. The glass-ceramic is formed from precursor glasses having the following compositions, in weight percent on an oxide basis: SiO2 30-60; Al2O3 10-25; MgO 13-30; K2O 8-20; TiO2 0-10; and GeO2 0-25. The glass-ceramic may be doped with up to 1 wt. % chromium oxide to impart optical activity thereto.
Claims15
A substantially transparent glass-ceramic based on a predominant crystal phase of forsterite, said glass-ceramic having a composition consisting essentially, in weight percent on an oxide basis, of
- SiO2 30-60 Al2O3 10-25 MgO 13-30 K2O 8-20 TiO2 0-10 GeO2 0-25.
A method of making a substantially transparent glass-ceramic containing a predominant crystal phase of forsterite, the method comprising the steps of:
- a.) melting a batch for a glass having a composition consisting essentially, in weight percent on an oxide basis, of SiO2 30-60;
- Al2O3 10-25;
- MgO 13-30;
- K2O 8-20;
- TiO2 0-10;
- and GeO2 0-25.
- b.) cooling the glass to a temperature at least below the transformation range of the glass;
- c.) exposing the glass to a temperature between about 600-1000° C. for a period of time sufficient to cause the generation of a glass-ceramic which is substantially transparent and which contains a predominant crystal phase of forsterite;
- and,
- d.) cooling the glass-ceramic to room temperature.
Dependencies are inferred from the claim text.