Transparent, colorless titania-free beta-quartz glass-ceramic
AssigneeEurokera
InventorsBruce Gardiner Aitken, Marie Jacqueline Monique Comte, Lothar Wondraczek
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Abstract
The invention relates to a transparent and essentially colorless β-quartz glass-ceramic material which is free of TiO2, As2O3, Sb2O3 and phosphates; articles formed from said glass-ceramic material; lithium aluminosilicate glasses, precursors for said glass-ceramic material; and methods of producing said glass-ceramic material and said articles formed from said glass-ceramic material.
Claims8
An essentially colorless, transparent glass-ceramic material containing a solid solution of β-quartz as a principal crystalline phase, having a composition, expressed in percentages by weight on a basis of oxides, consisting essentially of:
- SiO2
- 66-72
- Al2O3
- 18.3-24
- Li2O
- 22-5
- ZrO2
- 2-5
- SnO2
- >0.4-3
- CeO2
- 0-<1
- WO3 + MoO3
- 0-<1
- CeO2 + WO3 + MoO3
- 0-<1
- Nb2O5
- 0-3
- CeO2 + WO3 + MoO3 + Nb2O5
- 0-3
- MgO
- 0-3
- ZnO
- 0-4
- SrO
- 0-2.5
- BaO
- 0-2.5
- K2O + Na2O
- 0-<1
- Gd2O3 + La2O3 + Ta2O5 + Y2O5
- 0-4
- Nd2O3 + Er2O3
- 0-0.1 and
- Fe2O3
- <0.04;
- wherein, with the exception of inevitable traces, the composition is essentially free of titanium dioxide, arsenic oxide, antimony oxide and phosphates, and the weight percentages of MgO, ZnO, SrO and BaO in the composition are such that (i) MgO+ZnO is in a range of 2.2-4.6, and/or (ii) ZnO+BaO+SrO is in a range of 1-4.
Dependencies are inferred from the claim text.