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US 5,698,019 AGranted
Leucite-containing phosphosilicate glass-ceramic
AssigneeIvoclar AG
InventorsMartin Frank, Marcel Schweiger, Volker Rheinberger, Wolfram Hoeland
Life of this patent
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Abstract
A leucite-containing phosphosilicate glass-ceramic is described which, in addition to a leucite crystalline phase and at least one further crystalline phase, also contains one or more glass phases.
Claims15
A leucite-containing phosphosilicate glass-ceramic comprising a leucite crystalline phase and at least one further crystalline phase and at least one glass phase, and comprising the following components:
- ______________________________________ SiO.sub.2 49.0 to 57.5% by wt. Al.sub.2 O.sub.3 11.4 to 21.0% by wt. P.sub.2 O.sub.5 0.5 to 5.5% by wt. CaO 2.5 to 11.5% by wt. K.sub.2 O 9.0 to 22.5% by wt. Na.sub.2 O 1.0 to 9.5% by wt. Li.sub.2 O 0 to 2.5% by wt. B.sub.2 O.sub.3 0 to 2.0% by wt. TiO.sub.2 0 to 3.0% by wt. ZrO.sub.2 0.8 to 8.5% by wt. CeO.sub.2 0 to 3.0% by wt. F 0.25 to 2.5% by wt. La.sub.2 O.sub.3 0 to 3.0% by wt. ZnO 0 to 3.0% by wt. BaO 0 to 3.0% by wt. MgO 0 to 3.0% by wt. SrO 0 to 3.0% by wt. ______________________________________
A process for the preparation of a glass-ceramic comprising:
- (a) preparing a glass composition comprising:
- 49.0 to 57.5% by wt. SiO.sub.2, 11.4 to 21.0% by wt. Al.sub.2 O.sub.3, 0.5 to 5.5% by wt. P.sub.2 O.sub.5, 2.5 to 11.5% by wt. CaO, 9.0 to 22.5% by wt. K.sub.2 O , 1.0 to 9.5% by wt. Na.sub.2 O, 0 to 2.5% by wt. Li.sub.2 O, 0 to 2.0% by wt. B.sub.2 O.sub.3, 0 to 3.0% by wt. TiO.sub.2, 0.8 to 8.5% by wt. ZrO.sub.2, 0 to 3.0% by wt. CeO.sub.2, 0.25 to 2.5% by wt. F, 0 to 3.0% by wt. La.sub.2 O.sub.3, 0 to 3.0% by wt. ZnO, 0 to 3.0% by wt. BaO, 0 to 3.0% by wt. MgO, and 0 to 3.0% by wt. SrO;
- (b) providing the glass of (a) in the form of a powder or granulate or of a green compact pressed out of powder;
- (c) subjecting the powder of (b) to a heat treatment in the temperature range of from 850.degree. C. to 1200.degree. C. for a period of from 30 minutes to 4 hours;
- and
- (d) forming a glass-ceramic comprising a leucite crystalline phase.
3 more elements
Dependencies are inferred from the claim text.