Glass-ceramic materials, precursor glass thereof and process for making the same

• US 20070004578A1
• Filed: 06/26/2006
• Published: 01/04/2007
• Est. Priority Date: 06/30/2005
• Status: Active Grant

• Current Assignee: Eurokera S.N.C. (Corning Incorporated)
• Original Assignee: Eurokera S.N.C. (Corning Incorporated)
• Inventors: Monique Comte, Marie
• Granted Patent: US 7,465,686 B2
• Time in Patent Office: Days
• US Class Current: 501/4
• CPC Class Codes: C03C 1/004 Refining agents refining C03B5/225
• CPC Class Codes: C03C 10/0009 containing silica as main constituent
• CPC Class Codes: C03C 10/0027 containing SiO2, Al2O3, Li2O as main constituents
• CPC Class Codes: C03C 3/112 containing fluorine

Abstract

The invention relates to: a method of preparing glass-ceramics of β-quartz and/or of β-spodumene; a method of preparing articles made from said glass-ceramics; novel glass-ceramics of β-quartz and/or of β-spodumene; articles made from said novel glass-ceramics; and lithium aluminosilicate glasses, which are precursors of such novel glass-ceramics. The present invention relates to the use, as agent for fining the glass-ceramic glass precursor, of fluorine and at least one oxide of a multivalent element.

Claims

1. A method of preparing a glass-ceramic containing a solid solution of β

-quartz or of β

-spodumene (solid solutions of β

-quartz and β

-spodumene), as main crystalline phase(s), comprising heat-treating a lithium aluminosilicate glass, which is a precursor of such a glass-ceramic, under conditions which ensure its ceramming, characterized in that said glass jointly contains, as fining agent, fluorine and at least one oxide of a multivalent element which is different from arsenic oxide and from antimony oxide.

3. The method according to claim 1, characterized in that said glass or said filler contains, with the exception of inevitable traces, neither arsenic, nor antimony.

4. The method according to claim 1, characterized in that said at least one oxide of a multivalent element is selected from SnO₂, V₂O₅, CeO₂, MnO₂, and Fe₂O₃.

5. The method according to claim 1, characterized in that said fluorine is added in an amount between 0.1 and 2% by weight;

and in that said at least one oxide of a multivalent element is added in an amount between 0.2% and 2% by weight;

SnO₂ not being incorporated at more than 0.7% by weight.

2. A method of preparing an article made from a glass-ceramic containing a solid solution of β

-quartz or of β

-spodumene (solid solutions of β

-quartz and β

-spodumene) as main crystalline phase(s), said method comprising;

melting a lithium aluminosilicate glass or a filler, which is a precursor of such a glass;

said glass or said filler containing an effective and non-excess amount of at least one fining agent;

followed by fining the molten glass obtained;

cooling the molten fined glass obtained, and, simultaneously, shaping it into the shape desired for the article sought after; and

ceramming said shaped glass;

characterized in that said glass or said filler contains, as fining agent, fluorine and at least one oxide of a multivalent element which is different from arsenic oxide and from antimony oxide.

6. A glass-ceramic containing a solid solution of β

-quartz or of β

-spodumene (solid solutions of β

-quartz and β

-spodumene), as main crystalline phase(s), the composition of which, expressed as percentages by weight of oxides, essentially consists of;

7. The glass-ceramic according to claim 6, the composition essentially consisting of:

8. The glass-ceramic according to claim 6, the composition of which essentially consists of:

9. The glass-ceramic according to claim 6, the composition of which contains:

10. The glass-ceramic according to claim 6, the composition of which further contains an effective amount of at least one colorant, advantageously selected from CoO, Cr₂O₃, Fe₂O₃, MnO₂, NiO, V₂O₅, and CeO₂.

11. The glass-ceramic according to claim 6, the composition of which contains, with the exception of inevitable traces, neither arsenic, nor antimony.

12. An article made from a glass-ceramic according to claim 6, which notably consists of a cook-top, a cooking utensil, a microwave oven plate, a fireplace window, a fire-door or fire-window, a pyrolysis- or catalysis-oven window.

13. A lithium aluminosilicate glass, which is a precursor of a glass-ceramic according to claim 6, the composition of which corresponds to that of a glass-ceramic according to claim 6.

14. The lithium aluminosilicate glass according to claim 13, the composition of which contains, with the exception of inevitable traces, neither arsenic, nor antimony.

15. A lithium aluminosilicate glass, which is a precursor of a glass-ceramic according to claim 7, the composition of which corresponds to that of a glass-ceramic according to claim 7.

16. A lithium aluminosilicate glass, which is a precursor of a glass-ceramic according to claim 8, the composition of which corresponds to that of a glass-ceramic according to claim 8.

17. A lithium aluminosilicate glass, which is a precursor of a glass-ceramic according to claim 9, the composition of which corresponds to that of a glass-ceramic according to claim 9.