GLASSES HAVING IMPROVED TOUGHNESS AND SCRATCH RESISTANCE

• US 20090142568A1
• Filed: 11/25/2008
• Published: 06/04/2009
• Est. Priority Date: 11/29/2007
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Morena, Robert Michael, Ellison, Adam James, Dejneka, Matthew John, Gomez, Sinue
• Granted Patent: US 8,969,226 B2
• Time in Patent Office: Days
• US Class Current: 428/220
• CPC Class Codes: C03C 21/00 Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface
• CPC Class Codes: C03C 2204/00 Glasses, glazes or enamels with special properties
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C03C 3/093 containing zinc or zirconium
• CPC Class Codes: C03C 4/18 for ion-sensitive glass
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

Abstract

A silicate glass that is tough and scratch resistant. The toughness is increased by minimizing the number of non-bridging oxygen atoms in the glass. In one embodiment, the silicate glass is an aluminoborosilicate glass in which −15 mol 1%≦(R₂O+R′O—Al₂O₃—ZrO₂)—B₂O₃≦4 mol %, where R is one of Li, Na, K, Rb, and Cs, and R′ is one of Mg, Ca, Sr, and Ba.

Claims

1. A silicate glass, the silicate glass comprising:

a. at least one of alumina and boron oxide; and

b. at least one of an alkali metal oxide and an alkali earth metal oxide, wherein −

15 mol %≦

(R₂O+R′

O—

Al₂O₃—

ZrO₂)—

B₂O₃≦

4 mol %, where R is one of Li, Na, K, Rb, and Cs, and R′

is one of Mg, Ca, Sr, and Ba.

2. The silicate glass according to claim 1, wherein the silicate glass has a toughness in a range from about 0.7 MPa m^0.5 up to about 1.2 MPa m^0.5.

3. The silicate glass according to claim 2, wherein the silicate glass has a brittleness of less than about 8.5 μ

m<sup>−

0.5</sup>.

4. The silica glass according to claim 1, wherein the silicate glass comprises both alumina and boron oxide.

5. The silicate glass according to claim 1, wherein the silicate glass comprises at least one alkali metal oxide, and wherein the silicate glass is ion exchangeable.

6. The silicate glass according to claim 5, wherein the silicate glass, when ion exchanged, has a surface compressive stress of at least about 200 MPa and a surface compressive layer, the surface compressive layer having a depth of at least about 30 μ

m.

7. The silicate glass according to claim 5, wherein the at least one alkali metal oxide in the silicate glass is ion exchanged with at least one of sodium ions, silver ions, potassium ions, cesium ions, and rubidium ions.

8. The silicate glass according to claim 1, wherein the silicate glass has a liquidus viscosity of at least 100 kpoise.

9. The silicate glass according to claim 8, wherein the silicate glass is substantially free of lithium.

10. The silicate glass according to claim 9, wherein the silicate glass is down-drawable.

11. The silicate glass according to claim 10, wherein the silicate glass is slot drawn or fusion drawn.

12. The silicate glass according to claim 1, wherein the silicate glass forms a cover plate for a mobile electronic device.

13. The silicate glass according to claim 12, wherein the cover plate has a thickness in a range from about 0.3 mm up to about 1.5 mm.

14. The silicate glass according to claim 1, wherein the silicate glass is substantially free of antimony and arsenic oxides.

15. The silicate glass according to claim 1, wherein the silicate glass comprises 62-70 mol. % SiO₂;

0-18 mol % Al₂O₃;

0-10 mol % B₂O₃;

0-15 mol % Li₂O;

0-20 mol % Na₂O;

0-18 mol % K₂O;

0-17 mol % MgO;

0-18 mol % CaO; and

0-5 mol % ZrO₂.

16. The silicate glass according to claim 15, wherein the silicate glass comprises:

64-66 wt. % SiO₂;

8-12 wt. % Al₂O₃;

1-11 wt. % B₂O₃;

0-5 wt. % Li₂O;

6-12 wt. % Na₂O;

1-4 wt % K₂O;

0-4 wt. % MgO;

0-6 mol % CaO; and

0-2 wt. % ZrO₂.

17. The silicate glass according to claim 16, wherein 20 mol %≦

R₂O+R′

O≦

24 mol %.

18. The silicate glass according to claim 16, wherein 16 mol %≦

Al₂O₃+B₂O₃+ZrO₂≦

29 mol %.

19. An aluminoborosilicate glass, the aluminoborosilicate glass having a toughness in a range from about 0.7 MPa m^0.5 up to about 1.2 MPa m^0.5 and brittleness of less than about 8.5 μ

m<sup>−

0.5</sup>.

20. The aluminoborosilicate glass according to claim 19, wherein the aluminoborosilicate glass comprises at least one of alumina and boron oxide;

and at least one of an alkali metal oxide and an alkali earth metal oxide, wherein −

15 mol %≦

(R₂O+R′

O—

Al₂O₃—

ZrO₂)—

B₂O₃≦

3 mol %, where R′

is one of Li, Na, K, Rb, and Cs, and R′

is one of Mg, Ca, Sr, and Ba.

21. The aluminoborosilicate glass according to claim 19, wherein the aluminoborosilicate glass comprises:

64-66 wt. % SiO₂;

8-12 wt. % Al₂O₃;

1-11 wt. % B₂O₃;

0-5 wt. % Li₂O;

6-12 wt. % Na₂O;

1-4 wt % K₂O;

0-4 wt. % MgO;

0-6 mol % CaO; and

0-2 wt. % ZrO₂.

22. The aluminoborosilicate glass according to claim 21, wherein 20 mol %≦

R₂O+R′

O≦

24 mol %.

23. The aluminoborosilicate glass according to claim 21, wherein 16 mol %≦

Al₂O₃+B₂O₃+ZrO₂≦

29 mol %.

24. An aluminoborosilicate glass, the aluminoborosilicate glass comprising a plurality of non-bridging oxygen atoms NBO, wherein the plurality of non-bridging oxygen atoms NBO is given by NBO=R₂O+R′

O—

Al₂O₃—

ZrO₂, wherein R₂₀, R′

O, Al₂O₃, and ZrO₂ are expressed in mol %, wherein R is one of Li, Na, K, Rb, and Cs, and R′

is one of Mg, Ca, Sr, and Ba, and wherein −

15 mol %≦

NBO—

B₂O₃≦

3 mol %.

25. The aluminoborosilicate glass according to claim 24, wherein the aluminoborosilicate glass comprises:

64-66 wt. % SiO₂;

8-12 wt. % Al₂O₃;

1-11 wt. % B₂O₃;

0-5 wt. % Li₂O;

6-12 wt. % Na₂O;

1-4 wt % K₂O;

0-4 wt. % MgO;

0-6 mol % CaO; and

0-2 wt. % ZrO₂, and wherein −

5 mol %≦

(R₂O+R′

O—

Al₂O₃—

ZrO₂)—

B₂O₃≦

4 mol %.