DEEP NON-FRANGIBLE STRESS PROFILES AND METHODS OF MAKING

• US 20160122240A1
• Filed: 11/04/2015
• Published: 05/05/2016
• Est. Priority Date: 11/04/2014
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Oram, Pascale, Roussev, Rostislav Vatchev, Schneider, Vitor Marino, Young, Emily Elizabeth
• Granted Patent: US 10,239,784 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C03C 21/002 to perform ion-exchange between alkali ions C03C21/005 takes precedence
• CPC Class Codes: C03C 3/097 containing phosphorus, niobium or tantalum

Abstract

A non-frangible glass article strengthened by a dual or two-step ion exchange (IOX) process, where the first IOX step leads to a depth of compressive layer FSM_DOL>0.1·t or, in some embodiments, FSM_DOL>0.15·t, where t is the thickness of the glass, is provided. The glass article has a compressive stress CS1 after the first IOX step at the surface of from 100 MPa to 400 MPa or, in some embodiments, from 150 MPa to 300 MPa. The first IOX step is followed by a second IOX step, leading to a “spike” compressive stress CS2 after the second IOX step at the surface of greater than 500 MPa or, in some embodiments, 700 MPa. The width of the spike generated by the second IOX is between 1 μm and 30 μm, or between 8 μm and 15 μm, using the criteria where the magnitude (absolute value) of the slope of the spike is higher than 20 MPa/μm.

Claims

1. A glass article having a thickness t, a center at t/2, and a compressive layer extending from a surface of the glass article to a depth of layer DOL of greater 0.1·

t, where t is the thickness of the glass, the glass article having a maximum compressive stress CS of greater than about 500 MPa at the surface, and a stress profile having a spike region extending from the surface to about 30 μ

m below the surface, the stress profile in the spike region having a slope, the slope having an absolute value of greater than about 20 MPa/μ

m.

2. The glass article of claim 1, wherein the glass is non-frangible.

3. The glass article of claim 1, wherein the compressive layer has a Physical_DOL of greater than 0.8·

t.

4. The glass article of claim 1, wherein the maximum compressive stress CS is greater than about 700 MPa.

5. The glass article of claim 1, wherein the spike region extends from the surface to a depth in a range from about 8 μ

m to about 15 μ

m below the surface.

6. The glass article of claim 1, wherein the thickness t is 0.8 mm, the depth of layer DOL is greater than about 120 μ

m, and the maximum compressive stress is greater than about 700 MPa.

7. The glass of claim 1, wherein the glass article has a tensile region under a physical center tension CT extending from the depth of layer or depth of compression to the center of the glass, wherein the physical center tension CT is greater than |−

1.956×

10<sup>−

16</sup>×

t⁶+1.24274×

10<sup>−

12</sup>×

t⁵−

3.09196×

10<sup>−

9</sup>×

t⁴+3.80391×

10<sup>−

6</sup>×

t³−

2.35207×

10<sup>−

3</sup>×

t²+5.96241×

10<sup>−

1</sup>×

t+36.5994|.

8. The glass article of claim 1, wherein the glass article comprises an alkali aluminosilicate glass.

9. The glass article of claim 8, wherein the alkali aluminosilicate glass comprises at least about 4 mol % P₂O₅ and from 0 mol % to about 5 mol % B₂O₃, wherein 1.3<

[(P₂O₅+R₂O)/M₂O₃]≦

2.3, where M₂O₃=Al₂O₃+B₂O₃, and R₂O is the sum of monovalent cation oxides present in the alkali aluminosilicate glass.

10. The glass article of claim 9, wherein the glass comprises from about 40 mol % to about 70 mol % SiO₂;

from about 11 mol % to about 25 mol % Al₂O₃;

from 0 mol % to about 5 mol % B₂O₃;

from about 4 mol % to about 15 mol % P₂O₅;

from about 13 mol % to about 25 mol % Na₂O; and

from 0 mol % to about 1 mol % K₂O.

11. The glass article of claim 9, wherein 11 mol %≦

M₂O₃≦

30 mol %.

12. The glass article of claim 9, wherein R_xO is the sum of alkali metal oxides, alkaline earth metal oxides, and transition metal monoxides present in the glass, and wherein 13 mol %≦

R_xO≦

30 mol %.

13. The glass article of claim 8, wherein the glass article is lithium-free.

14. A glass article having a thickness t in a range from 0.4 mm to about 1.5 mm, a center at t/2, a compressive layer extending from a surface of the glass article to a depth of layer DOL or depth of compression DOC, and a tensile region under a physical center tension CT extending from the depth of layer or depth of compression to the center, wherein:

a. the physical center tension CT is greater than |−

1.956×

10<sup>−

16</sup>×

t⁶+1.24274×

10<sup>−

12</sup>×

t⁵−

3.09196×

10<sup>−

9</sup>×

t⁴+3.80391×

10<sup>−

6</sup>×

t³−

2.35207×

10<sup>−

3</sup>×

t²+5.96241×

10<sup>−

1</sup>×

t+36.5994|; and

b. the glass article has a total elastic energy normalized per thickness of the glass E_total, wherein (E_total/t(mm))=174.75 J/m²·

mm, wherein the glass article is non-frangible.

15. The glass article of claim 14, wherein the thickness is 0.8 mm, the physical center tension CT is greater than |45 MPa|, and the total elastic energy E_total is less than about 139.8 J/m².

16. The glass article of claim 14, wherein the thickness is 0.5 mm, the physical center tension CT is greater than |63 MPa|, and the total elastic energy E_total is less than 87.4 J/m².

17. A glass article having a thickness t in a range from about 0.4 mm to about 1 mm, a compressive layer extending from a surface of the glass article to a depth of layer DOL or depth of compression DOC, a center at t/2, and a tensile region under a physical center tension CT extending from the depth of layer or depth of compression to the center of the glass, wherein:

a. the physical center tension CT is greater than |−

1.956×

10<sup>−

16</sup>×

t⁶+1.24274×

10<sup>−

12</sup>×

t⁵−

3.09196×

10<sup>−

9</sup>×

t⁴+3.80391×

10<sup>−

6</sup>×

t³−

2.35207×

10<sup>−

3</sup>×

t²+5.96241×

10<sup>−

1</sup>×

t+36.5994|; and

b. the glass article has an elastic energy stored in the interior of the sample in tension of E_interior, wherein (E_interior/t(mm))=30 J/m²·

mm, wherein the glass article is non-frangible.

18. The glass article of claim 17, wherein the thickness is 0.8 mm, the physical center tension CT is greater than |45 MPa| and E_interior is less than about 24 J/m².

19. The glass article of claim 17, wherein the thickness is 0.5 mm, the physical center tension CT is greater than |63 MPa| and E_interior is less than about 18 J/m².

20. A glass article strengthened by a two-step ion exchange process comprising a first ion exchange step and a second ion exchange step, the glass article having a thickness t in a range from about 0.4 mm to about 1 mm, a center at t/2, a compressive layer extending from a surface of the glass article to a depth of layer DOL or a depth of compression DOC, and a tensile region under a physical center tension CT extending from the depth of layer to the center of the glass article, wherein the glass article has a compressive stress CS1 of from 100 MPa to 400 MPa and a depth of layer FMS_DOL greater than 0.1·

t after the first ion exchange step at the surface and after the second ion exchange step a compressive stress CS2 of greater than about than 500 MPa at the surface and a stress profile having a spike region in a range from about the surface to about 30 μ

m, wherein the stress profile in the spike region has a slope has having an absolute value of greater than about 20 MPa/μ

m.

21. The glass article of claim 20, wherein the glass is non-frangible.

22. The glass article of claim 20, wherein 1 the compressive layer has a Physical_DOL of greater than 0.8·

t.

23. The glass article of claim 20, wherein the maximum compressive stress CS is greater than about 700 MPa.

24. The glass article of claim 20, wherein the spike region extends from the surface of the glass to a depth in a range from about 8 μ

m to about 15 μ

m below the surface.

25. The glass article of claim 20, wherein the thickness t is 0.8 mm, the depth of layer DOL is greater than about 120 μ

m, and the maximum compressive stress is greater than about 700 MPa.

26. The glass of claim 20, wherein the glass article has a tensile region under a physical center tension CT extending from the depth of layer or depth of compression to the center of the glass at t/2, wherein the physical center tension CT is greater than |−

1.956×

10<sup>−

16</sup>×

t⁶+1.24274×

10<sup>−

12</sup>×

t⁵−

3.09196×

10<sup>−

9</sup>×

t⁴+3.80391×

10<sup>−

6</sup>×

t³−

2.35207×

10<sup>−

3</sup>×

t²+5.96241×

10<sup>−

1</sup>×

t+36.5994|.

27. The glass article of claim 20, wherein the glass article comprises an alkali aluminosilicate glass.

28. The glass article of claim 27, wherein the alkali aluminosilicate glass comprises at least about 4 mol % P₂O₅ and from 0 mol % to about 5 mol % B₂O₃, wherein 1.3<

[(P₂O₅+R₂O)/M₂O₃]≦

2.3, where M₂O₃=Al₂O₃+B₂O₃, and R₂O is the sum of monovalent cation oxides present in the alkali aluminosilicate glass.

29. The glass article of claim 28, wherein the glass comprises from about 40 mol % to about 70 mol % SiO₂;

from about 11 mol % to about 25 mol % Al₂O₃;

from 0 mol % to about 5 mol % B₂O₃;

from about 4 mol % to about 15 mol % P₂O₅;

from about 13 mol % to about 25 mol % Na₂O; and

from 0 mol % to about 1 mol % K₂O.

30. The glass article of claim 28, wherein 11 mol %≦

M₂O₃≦

30 mol %.

31. The glass article of claim 28, wherein R_xO is the sum of alkali metal oxides, alkaline earth metal oxides, and transition metal monoxides present in the glass, and wherein 13 mol %≦

R_xO≦

30 mol %.

32. The glass article of claim 27, wherein the glass article is lithium-free.

33. A method of strengthening a glass article having a thickness t and a stress profile, the method comprising:

a. ion exchanging the glass article in a first ion exchange bath, the first ion exchange bath comprising a potassium salt and at least 30 wt % of a sodium salt, to form a compressive layer having a compressive stress CS1 at the surface of from about 100 MPa to about 400 MPa, the compressive layer extending from a surface of the glass article to a depth of layer FSM_DOL of greater than 0.1·

t, or depth of compression DOC, and a tensile region under a physical center tension CT extending from the depth of layer or depth of compression to the center of the glass at t/2; and

b. ion exchanging the glass article in a second ion exchange bath, the second ion exchange bath comprising at least 90 wt % of a potassium salt, to form a spike region extending from the surface to a depth of about 30 μ

m below the surface, the spike region having a maximum compressive stress CS of greater than about 500 MPa at the surface, wherein the stress profile in the spike region has a slope, the slope having an absolute value of greater than about 20 MPa/μ

m.

34. The method of claim 33, wherein the glass article in non-frangible after ion exchanging in the second ion exchange bath.

35. The method of claim 33, wherein 1 the compressive layer has a Physical_DOL of greater than 0.8·

t after ion exchanging in the second ion exchange bath.

36. The method of claim 33, wherein the maximum compressive stress CS is greater than about 700 MPa.

37. The method of claim 33, wherein the spike region extends from the surface to a depth in a range from about 8 μ

m to about 15 μ

m below the surface.

38. The method of claim 33, wherein the thickness t is 0.8 mm, the depth of layer DOL is greater than about 120 μ

m, and the maximum compressive stress is greater than about 700 MPa.

39. The method of claim 33, wherein the glass article comprises an alkali aluminosilicate glass.

40. The method of claim 39, wherein the alkali aluminosilicate glass comprises at least about 4 mol % P₂O₅ and from 0 mol % to about 5 mol % B₂O₃, wherein 1.3<

[(P₂O₅+R₂O)/M₂O₃]≦

2.3, where M₂O₃=Al₂O₃+B₂O₃, and R₂O is the sum of monovalent cation oxides present in the alkali aluminosilicate glass.

41. The method of claim 40, wherein the glass comprises from about 40 mol % to about 70 mol % SiO₂;

from about 11 mol % to about 25 mol % Al₂O₃;

from 0 mol % to about 5 mol % B₂O₃;

from about 4 mol % to about 15 mol % P₂O₅;

from about 13 mol % to about 25 mol % Na₂O; and

from 0 mol % to about 1 mol % K₂O.

42. The method of claim 40, wherein 11 mol %≦

M₂O₃≦

30 mol %.

43. The method of claim 40, wherein R_xO is the sum of alkali metal oxides, alkaline earth metal oxides, and transition metal monoxides present in the glass, and wherein 13 mol %≦

R_xO≦

30 mol %.

44. The method of claim 39, wherein the glass article is lithium-free.