White, opaque, β spodumene glass-ceramic articles with inherent damage resistance and methods for making the same

Patent metadata

Field	Value
Publication number	US-10189735-B2
Application number	US-201715668190-A
Country	US
Kind code	B2
Filing date	Aug 3, 2017
Priority date	Jun 30, 2014
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

Crystallizable glasses, glass-ceramics, IXable glass-ceramics, and IX glass-ceramics are disclosed. The glass-ceramics exhibit β-spodumene ss as the predominant crystalline phase. These glasses and glass-ceramics, in mole %, include: 60-75 SiO 2 ; 10-18 Al 2 O 3 ; 5-14 Li 2 O; and 4.5 B 2 O 3 . The glass-ceramics also have a Vickers initiation crack threshold of at least about 25 kgf.

First claim

We claim:

1. A process for making a glass-ceramic comprising:
a) heating a crystallizable glass at a rate in a range from about 1° C./min to about 10° C./min to a nucleation temperature in a range from about 700° C. and 810° C., wherein, in mole %, the crystallizable glass comprises:
i) SiO 2 in a range from about 60 to about 75,
ii) Al 2 O 3 in a range from about 10 to about 18,
iii) Li 2 O in a range from about 5 to about 14, and
iv) B 2 O 3 in a range from about 4.5 to about 20;

b) maintaining the crystallizable glass at the nucleation temperature to produce a nucleated crystallizable glass;
c) heating the nucleated crystallizable glass at a rate in a range from about 1° C./min to about 10° C./min to a crystallization temperature of in a range from about 850° C. and 1200° C.; and
d) maintaining the nucleated crystallizable glass at the crystallization temperature to produce a glass-ceramic having β-spodumene as a predominant crystalline phase, wherein the glass-ceramic comprises a Vickers crack initiation threshold of at least about 25 kgf.

2. The process of claim 1 , further comprising ion exchanging the glass ceramic to form a compressive stress layer.

3. The process of claim 2 , wherein the compressive stress layer has a compressive stress of at least 80 MPa and a depth of layer (DOL) of at least about 2% of an overall thickness of the glass-ceramic.

4. The process of claim 1 , wherein at least about 50% of the B 2 O 3 present in a residual glass comprises three-fold coordination boron cations.

5. The process of claim 1 , wherein the Vickers crack initiation threshold is at least about 30 kgf.

6. The process of claim 1 , wherein the Vickers crack initiation threshold is at least about 35 kgf.

7. The process of claim 1 , wherein the Vickers crack initiation threshold is at least about 40 kgf.

8. The process of claim 1 , wherein the Vickers crack initiation threshold is at least about 45 kgf.

9. The process of claim 1 , wherein a ratio of the mole sum total [Li 2 O+Na 2 O+K 2 O+MgO+ZnO]/moles of [Al 2 O 3 ] in the crystallizable glass is in a range from about 0.8 to about 1.5.

10. The process of claim 1 , further comprising quenching to cool the glass-ceramic after d).

11. The process of claim 10 , comprising quenching once the glass-ceramic is at a temperature in a range from about 800° C. to about 1100° C.

12. The process of claim 1 , wherein the crystallizable glass further comprises:
v) MgO in a range from 0 to about 8,
vi) ZnO in a range from 0 to about 4,
vii) TiO 2 in a range from about 2 to about 5,
viii) Na 2 O in a range from 0 to about 5,
ix) K 2 O in a range from 0 to about 4, and
x) SnO 2 in a range from about 0.05 to about 0.5.

Assignees

• Corning Inc

Inventors

• Beall George Halsey
• Fu Qiang
• Smith Charlene Marie
• Youngman Randall Eugene

Classifications

• C03C21/002

  to perform ion-exchange between alkali ions (C03C21/005 takes precedence) · CPC title

• C03C3/093 Primary

  containing zinc or zirconium · CPC title

• C03C10/0027

  containing SiO2, Al2O3, Li2O as main constituents · CPC title

• C03B32/02 Primary

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

• C03C2204/00

  Glasses, glazes or enamels with special properties · CPC title