Beta-quartz glass-ceramics with high zinc content

Patent metadata

Field	Value
Publication number	US-11247935-B2
Application number	US-201816620302-A
Country	US
Kind code	B2
Filing date	Jun 6, 2018
Priority date	Jun 7, 2017
Publication date	Feb 15, 2022
Grant date	Feb 15, 2022

Abstract

The present application provides LAS type transparent glass-ceramics of β-quartz of composition containing a high content of zinc, articles constituted at least in part of said glass-ceramics, glasses precursors of said glass-ceramics (with a low viscosity at high temperature), and also a method of preparing said articles. Said glass-ceramics present a composition, free of arsenic oxide and antimony oxide, except for inevitable traces, expressed as percentages by weight of oxides, containing: 64.5% to 66.5% of SiO2; 19.0% to 20.6% of Al2O3; 3.0% to 3.6% of Li2O; 0 to 1% of MgO; 1.7% to 3.4% of ZnO; 2% to 3% of BaO; 0 to 3% of SrO; 0 to 1% of CaO; 2% to 4% of TiO2; 1% to 2% of ZrO2; 0 to 1% of Na2O; 0 to 1% of K2O; with Na2O+K2O+BaO+SrO+CaO≤6%; optionally up to 2% of at least one fining agent comprising SnO2; and optionally up to 2% of at least one coloring agent.

First claim

The invention claimed is:

1. A transparent glass-ceramic of lithium aluminosilicate containing a solid solution of β-quartz as a main crystalline phase, a composition of which, free of arsenic oxide and antimony oxide, except for inevitable traces, expressed in percentages by weight of oxides, comprises:
64.5% to 66.5% of SiO 2 ;
19.0% to 20.6% of Al 2 O 3 ;
3.0% to 3.6% of Li 2 O;
0 to 1% of MgO;
1.7% to 3.4% of ZnO;
2% to 3% of BaO;
0 to 3% of SrO;
0 to 1% of CaO;
2% to 4% of TiO 2 ;
1% to 2% of ZrO 2 ;
0 to 1% of Na 2 O;
0 to 1% of K 2 O;
greater than 0.02% to 0.1% of Cr 2 O 3 ;
with Na 2 O+K 2 O+BaO+SrO+CaO≤6% and 0.07%≤V 2 O 5 +Fe 2 O 3 +Cr 2 O 3 ≤0.39%; and
optionally up to 2% of at least one fining agent comprising SnO 2 .

2. The glass-ceramic according to claim 1 , wherein the composition comprises 3.1% to 3.5% of Li 2 O.

3. The glass-ceramic according to claim 1 , wherein the composition comprises 1.7% to 2.8% of ZnO.

4. The glass-ceramic according claim 1 , wherein the composition comprises 0.01 to 1% of MgO.

5. The glass-ceramic according to claim 1 , wherein the composition comprises 0.05% to 0.6% of SnO 2 .

6. The glass-ceramic according to claim 1 , wherein the composition further comprises V 2 O 5 as coloring agent, alone or mixed with at least one other coloring agent selected from CoO and Fe 2 O 3 .

7. The glass-ceramic according to claim 1 , having a coefficient of thermal expansion CTE 25-700° C. in the range +/−3·10 −7 K −1 .

8. An article constituted at least in part of a glass-ceramic according to claim 1 .

9. The glass-ceramic of claim 5 , wherein the composition comprises 0.15 to 0.4% of SnO 2 .

10. The glass-ceramic according to claim 1 , wherein the composition comprises:
0.005% to 0.2% of V 2 O 5 ;
0.01% to 0.32% of Fe 2 O 3 ; and
0% to 0.1% of CoO.

11. The glass-ceramic according to claim 1 , wherein the composition comprises:
0.015% to 0.1% of V 2 O 5 ;
0.07% to 0.25% of Fe 2 O 3 ; and
greater than 0.02% to 0.04% of Cr 2 O 3 .

Assignees

• Eurokera

Inventors

• Comte Marie
• Ogier Tiphaine

Classifications

• C03C3/087

  containing calcium oxide, e.g. common sheet or container glass · CPC title

• C03C10/0036

  containing SiO2, Al2O3 and a divalent metal oxide as main constituents · CPC title

• C03C10/0054

  containing PbO, SnO2, B2O3 · CPC title

• C03B27/012

  by heat treatment, e.g. for crystallisation; Heat treatment of glass products before tempering by cooling (C03B27/008, C03B27/016 take precedence) · CPC title

• C03B32/02

  Thermal crystallisation, e.g. for crystallising glass bodies into glass-ceramic articles {(C03B27/012 takes precedence)} · CPC title