STRENGTHENED GLASS WITH DEEP DEPTH OF COMPRESSION

• US 20150368153A1
• Filed: 06/16/2015
• Published: 12/24/2015
• Est. Priority Date: 06/19/2014
• Status: Abandoned Application

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Pesansky, Jonathan David, Reiman, Kevin Barry, Roussev, Rostislav Vatchev
• Application Number:
  US14/740,896
• Publication Number:
  US 20150368153A1
• 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 3/091 containing aluminium
• CPC Class Codes: C03C 3/093 containing zinc or zirconium
• CPC Class Codes: C03C 3/097 containing phosphorus, niobium or tantalum
• CPC Class Codes: Y10T 428/315 Surface modified glass [e.g., tempered, strengthened, etc.]

Abstract

Chemically strengthened glass articles having at least one deep compressive layer extending from a surface of the article to a depth of at least about 45 μm within the article are provided. In one embodiment, the compressive stress profile includes a single linear segment extending from the surface to the depth of compression DOC. Alternatively, the compressive stress profile includes two linear portions: the first portion extending from the surface to a relatively shallow depth and having a steep slope; and a second portion extending from the shallow depth to the depth of compression. Methods of achieving such stress profiles are also described.

Claims

1. A glass article, the glass article having a compressive region having a compressive stress CS_s of at least about 150 MPa at a surface of the glass article, wherein:

a. the compressive region extends from the surface to a depth of compression DOC of at least about 45 μ

m and has a compressive stress profile; and

b. the compressive region has a compressive stress profile having a first portion a extending to a depth d_a of at least about 45 μ

m from the surface and having a slope m_a, wherein 2 MPa/μ

m≦

m_a≦

8 MPa/μ

m, and optionally a second portion a′

extending from the surface to a depth d_a′

of at least about 3 μ

m, wherein 40 MPa/μ

m≦

m_a′

≦

200 MPa/μ

m.

2. The glass article of claim 1, wherein the depth d_a is equal to the depth of compression and first portion a extends from the surface to d_a.

3. The glass article of claim 2, wherein 3 MPa/μ

m≦

m_a≦

6 MPa/μ

m.

4. The glass article of claim 2, wherein the depth of compression DOC is at least about 50 μ

m.

5. The glass article of claim 1, wherein the compressive stress profile includes:

the second portion a′

extending from the surface to a depth d_a′

and the first portion a extending from d_a′

up to the depth d_a

6. The glass article of claim 5, wherein 40 MPa/μ

m≦

m_a′

≦

120 MPa/μ

m.

7. The glass article of claim 1, wherein the glass article has a thickness in a range from about 0.1 mm up to about 1.5 mm.

8. The glass article of claim 7, wherein the thickness is in a range from about 0.1 mm up to about 1.0 mm.

9. The glass article of claim 8, wherein the thickness is in a range from about 0.1 mm up to about 0.5 mm.

10. The glass article of claim 1, wherein the glass article comprises and alkali aluminosilicate glass.

11. The glass article of claim 10, wherein the alkali aluminosilicate glass comprises:

from about 60 mol % to about 70 mol % SiO₂;

from about 6 mol % to about 14 mol % Al₂O₃;

from 0 mol % to about 15 mol % B₂O₃;

from 0 mol % to about 15 mol % Li₂O;

from 0 mol % to about 20 mol % Na₂O;

from 0 mol % to about 10 mol % K₂O;

from 0 mol % to about 8 mol % MgO;

from 0 mol % to about 10 mol % CaO;

from 0 mol % to about 5 mol % ZrO₂;

from 0 mol % to about 1 mol % SnO₂;

from 0 mol % to about 1 mol % CeO₂;

less than about 50 ppm As₂O₃; and

less than about 50 ppm Sb₂O₃;

wherein 12 mol %≦

Li₂O+Na₂O+K₂O≦

20 mol % and 0 mol %≦

MgO+CaO≦

10 mol %.

12. The glass article of claim 10, wherein the alkali aluminosilicate glass comprises:

at least about 50 mol % SiO₂;

at least about 10 mol % R₂O, wherein R₂O comprises Na₂O;

Al₂O₃, wherein −

0.5 mol %≦

Al₂O₃(mol %)—

R₂O(mol %)≦

2 mol %; and

B₂O₃, and wherein B₂O₃(mol %)—

(R₂O(mol %)—

Al₂O₃(mol %))≧

4.5 mol %.

13. The glass article of claim 10, wherein the alkali aluminosilicate glass comprises:

the alkali aluminosilicate glass is ion exchangeable and comprises;

at least about 50 mol % SiO₂;

at least about 10 mol % R₂O, wherein R₂O comprises Na₂O;

Al₂O₃; and

B₂O₃, wherein B₂O₃—

(R₂O—

Al₂O₃)≧

3 mol %.

14. The glass article of claim 10, wherein the alkali aluminosilicate glass comprises at least about 4 mol % P₂O₅ and from 0 mol % to about 4 mol % B₂O₃, and 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.

15. The glass article of claim 10, wherein the alkali aluminosilicate glass further comprises up to about 10 mol % Li₂O.

16. The glass article of claim 1, wherein the compressive stress at the surface is at least about 300 MPa.

17. A glass article, the glass article having a compressive layer having a compressive stress CS_s of at least about 150 MPa at a surface of the glass article, wherein:

a. the compressive layer extends from the surface to a depth of compression DOC of at least about 45 μ

m and has a compressive stress profile; and

b. the compressive stress profile comprises;

a. a first portion a extending from the surface to a depth d_a and having a slope m_a, wherein 3 μ

m≦

d_a≦

8 μ

m and 40 MPa/μ

m≦

m_a≦

200 MPa/μ

m; and

b. a second portion b extending from d_a to up to the depth of compression DOC and having a slope m_b, wherein 2 MPa/μ

m≦

m_b≦

8 MPa/μ

m.

18. The glass article of claim 17, wherein 40 MPa/μ

m≦

m_a≦

120 MPa/μ

m.

19. The glass article of claim 17, wherein 50 MPa/μ

m≦

m_a≦

120 MPa/μ

m.

20. The glass article of claim 17, wherein the glass article has a thickness in a range from about 0.1 mm up to about 1.5 mm.

21. The glass article of claim 20, wherein the thickness is in a range from about 0.1 mm up to about 1.0 mm.

22. The glass article of claim 21, wherein the thickness is in a range from about 0.1 mm up to about 0.5 mm.

23. The glass article of claim 17, wherein the glass article comprises and alkali aluminosilicate glass.

24. The glass article of claim 23, wherein the alkali aluminosilicate glass comprises:

from about 60 mol % to about 70 mol % SiO₂;

from about 6 mol % to about 14 mol % Al₂O₃;

from 0 mol % to about 15 mol % B₂O₃;

from 0 mol % to about 15 mol % Li₂O;

from 0 mol % to about 20 mol % Na₂O;

from 0 mol % to about 10 mol % K₂O;

from 0 mol % to about 8 mol % MgO;

from 0 mol % to about 10 mol % CaO;

from 0 mol % to about 5 mol % ZrO₂;

from 0 mol % to about 1 mol % SnO₂;

from 0 mol % to about 1 mol % CeO₂;

less than about 50 ppm As₂O₃; and

less than about 50 ppm Sb₂O₃;

wherein 12 mol %≦

Li₂O+Na₂O+K₂O≦

20 mol % and 0 mol %≦

MgO+CaO≦

10 mol %.

25. The glass article of claim 23, wherein the alkali aluminosilicate glass comprises:

at least about 50 mol % SiO₂;

at least about 10 mol % R₂O, wherein R₂O comprises Na₂O;

Al₂O₃, wherein −

0.5 mol %≦

Al₂O₃(mol %)—

R₂O(mol %)≦

2 mol %; and

B₂O₃, and wherein B₂O₃(mol %)—

(R₂O(mol %)—

Al₂O₃(mol %))≧

4.5 mol %.

26. The glass article of claim 23, wherein the alkali aluminosilicate glass comprises:

the alkali aluminosilicate glass is ion exchangeable and comprises;

at least about 50 mol % SiO₂;

at least about 10 mol % R₂O, wherein R₂O comprises Na₂O;

Al₂O₃; and

B₂O₃, wherein B₂O₃—

(R₂O—

Al₂O₃)≧

3 mol %.

27. The glass article of claim 23, wherein the alkali aluminosilicate glass comprises at least about 4 mol % P₂O₅ and from 0 mol % to about 4 mol % B₂O₃, and 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.

28. The glass article of claim 23, wherein the alkali aluminosilicate glass further comprises up to about 10 mol % Li₂O.

29. The glass article of claim 17, wherein the compressive stress at the surface is at least about 300 MPa.

30. A glass article, the glass article having a compressive region having a compressive stress CS_s of at least about 150 MPa at a surface of the glass article, wherein:

a. the compressive region extends from the surface to a depth of compression DOC of at least about 45 μ

m and has a compressive stress profile; and

b. the compressive stress profile has a first linear portion a extending from the surface to a depth d_a and a slope m_a, wherein the depth d_a is equal to the depth of compression and 2 MPa/μ

m≦

m_a≦

8 MPa/μ

m.

31. The glass article of claim 30, wherein 3 MPa/μ

m≦

m_a≦

6 MPa/μ

m.

32. The glass article of claim 30, wherein the depth of compression DOC is at least about 50 μ

m.

33. The glass article of claim 30, wherein the glass article has a thickness in a range from about 0.1 mm up to about 1.5 mm.

34. The glass article of claim 33, wherein the thickness is in a range from about 0.1 mm up to about 1.0 mm.

35. The glass article of claim 34, wherein the thickness is in a range from about 0.1 mm up to about 0.5 mm.

36. The glass article of claim 30, wherein the glass article comprises and alkali aluminosilicate glass.

37. The glass article of claim 36, wherein the alkali aluminosilicate glass comprises:

from about 60 mol % to about 70 mol % SiO₂;

from about 6 mol % to about 14 mol % Al₂O₃;

from 0 mol % to about 15 mol % B₂O₃;

from 0 mol % to about 15 mol % Li₂O;

from 0 mol % to about 20 mol % Na₂O;

from 0 mol % to about 10 mol % K₂O;

from 0 mol % to about 8 mol % MgO;

from 0 mol % to about 10 mol % CaO;

from 0 mol % to about 5 mol % ZrO₂;

from 0 mol % to about 1 mol % SnO₂;

from 0 mol % to about 1 mol % CeO₂;

less than about 50 ppm As₂O₃; and

less than about 50 ppm Sb₂O₃;

wherein 12 mol %≦

Li₂O+Na₂O+K₂O≦

20 mol % and 0 mol %≦

MgO+CaO≦

10 mol %.

38. The glass article of claim 36, wherein the alkali aluminosilicate glass comprises:

at least about 50 mol % SiO₂;

at least about 10 mol % R₂O, wherein R₂O comprises Na₂O;

Al₂O₃, wherein −

0.5 mol %≦

Al₂O₃(mol %)—

R₂O(mol %)≦

2 mol %; and

B₂O₃, and wherein B₂O₃(mol %)—

(R₂O(mol %)—

Al₂O₃(mol %))≧

4.5 mol %.

39. The glass article of claim 36, wherein the alkali aluminosilicate glass comprises:

the alkali aluminosilicate glass is ion exchangeable and comprises;

at least about 50 mol % SiO₂;

at least about 10 mol % R₂O, wherein R₂O comprises Na₂O;

Al₂O₃; and

B₂O₃, wherein B₂O₃—

(R₂O—

Al₂O₃)≧

3 mol %.

40. The glass article of claim 36, wherein the alkali aluminosilicate glass comprises at least about 4 mol % P₂O₅ and from 0 mol % to about 4 mol % B₂O₃, and 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 glass article of claim 36, wherein the alkali aluminosilicate glass further comprises up to about 10 mol % Li₂O.

42. The glass article of claim 30, wherein the compressive stress at the surface is at least about 300 MPa.

43. A glass article, the glass article having a compressive region having a compressive stress CS_s of at least about 130 MPa at a surface of the glass article, wherein:

a. the compressive region extends from the surface to a depth of compression DOC of at least about 100 μ

m and has a compressive stress profile; and

b. the compressive stress profile has a first linear portion a extending from the surface to a depth d_a and a slope m_a, wherein the depth d_a is equal to the depth of compression and 0.7 MPa/μ

m≦

m_a≦

2.0 MPa/μ

m.

44. The glass article of claim 43, wherein the depth of compression DOC is at least about 140 μ

m.

45. The glass article of claim 43, wherein the glass article has a thickness in a range from about 0.1 mm up to about 1.5 mm.

46. The glass article of claim 45, wherein the thickness is in a range from about 0.1 mm up to about 1.0 mm.

47. The glass article of claim 46, wherein the thickness is in a range from about 0.1 mm up to about 0.5 mm.

48. The glass article of claim 43, wherein the glass article comprises and alkali aluminosilicate glass.

49. The glass article of claim 48, wherein the alkali aluminosilicate glass comprises:

from about 60 mol % to about 70 mol % SiO₂;

from about 6 mol % to about 14 mol % Al₂O₃;

from 0 mol % to about 15 mol % B₂O₃;

from 0 mol % to about 15 mol % Li₂O;

from 0 mol % to about 20 mol % Na₂O;

from 0 mol % to about 10 mol % K₂O;

from 0 mol % to about 8 mol % MgO;

from 0 mol % to about 10 mol % CaO;

from 0 mol % to about 5 mol % ZrO₂;

from 0 mol % to about 1 mol % SnO₂;

from 0 mol % to about 1 mol % CeO₂;

less than about 50 ppm As₂O₃; and

less than about 50 ppm Sb₂O₃;

wherein 12 mol %≦

Li₂O+Na₂O+K₂O≦

20 mol % and 0 mol %≦

MgO+CaO≦

10 mol %.

50. The glass article of claim 48, wherein the alkali aluminosilicate glass comprises:

at least about 50 mol % SiO₂;

at least about 10 mol % R₂O, wherein R₂O comprises Na₂O;

Al₂O₃, wherein −

0.5 mol %≦

Al₂O₃(mol %)—

R₂O(mol %)≦

2 mol %; and

B₂O₃, and wherein B₂O₃(mol %)—

(R₂O(mol %)—

Al₂O₃(mol %))≧

4.5 mol %.

51. The glass article of claim 48, wherein the alkali aluminosilicate glass comprises:

the alkali aluminosilicate glass is ion exchangeable and comprises;

at least about 50 mol % SiO₂;

at least about 10 mol % R₂O, wherein R₂O comprises Na₂O;

Al₂O₃; and

B₂O₃, wherein B₂O₃—

(R₂O—

Al₂O₃)≧

3 mol %.

52. The glass article of claim 48, wherein the alkali aluminosilicate glass comprises at least about 4 mol % P₂O₅ and from 0 mol % to about 4 mol % B₂O₃, and 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.

53. The glass article of claim 48, wherein the alkali aluminosilicate glass further comprises up to about 10 mol % Li₂O.

54. The glass article of claim 48, wherein the alkali aluminosilicate glass further comprises up to about 0.5 mol % Li₂O.

63. The method of claim 50, wherein the second ion exchange step is conducted for a time of about 10 to about 30 minutes.

55. A method of producing a strengthened glass article having at least one compressive stress layer extending from a surface of the strengthened glass article to a depth of compression DOC of at least about 45 μ

m, the method comprising;

a. conducting a first ion exchange step by immersing an alkali aluminosilicate glass article in a first ion exchange bath at a temperature of greater than 400°

C. for a time sufficient such that the compressive stress layer has a depth of at least 45 μ

m after the first ion exchange step; and

b. conducting a second ion exchange step by immersing the alkali aluminosilicate glass article in a second ion exchange bath different from the first ion exchange bath at a temperature of at least about 350°

C. for a time sufficient to produce the compressive layer having the depth of compression DOC of at least about 45 μ

m.

56. The method of claim 55, wherein the first ion exchange step is conducted for a time of at least 8 hours.

57. The method of claim 55, wherein the first ion exchange bath delivers sodium ions to the alkali aluminosilicate glass article and comprises at least about 30% by weight of a sodium salt with the balance of the ion exchange bath comprising a potassium salt a potassium salt.

58. The method of claim 57, wherein the first ion exchange bath comprises from about 40% to about 60% by weight of the sodium salt.

59. The method of claim 55, wherein the temperature of the first ion exchange step is 440°

C. or greater.

60. The method of claim 55, wherein the strengthened glass article has a compressive stress at the surface of at least 150 MPa after the first ion exchange step.

61. The method of claim 60, wherein the compressive stress at the surface is in a range from about 200 to about 300 MPa after the first ion exchange step.

62. The method of claim 55, wherein the second ion exchange step is conducted for a time of 60 minutes or less.

64. The method of claim 55, wherein the second ion exchange bath comprises at least about 95% by weight of a potassium composition that delivers potassium ions to the alkali aluminosilicate glass article.

65. The method of claim 64, wherein the second ion exchange bath comprises from about 98% to about 99.5% by weight of the potassium composition.

66. The method of claim 64, wherein the second ion exchange bath comprises 0-2% by weight of a sodium composition.

67. The method of claim 55, wherein the temperature of the second ion exchange step is 390°

C. or greater.

68. The method of claim 55, wherein the strengthened glass article has a compressive stress of at least about 700 MPa after the second ion exchange step.

69. The method of claim 68, wherein the compressive stress is in a range from about 700 to about 1000 MPa after the second ion exchange step.

70. The method of claim 69, wherein the compressive stress layer has a depth of compression of at least about 60 μ

m after the first ion exchange step.

71. The method of claim 70, wherein the depth of compression is in a range from about 90 μ

m to about 130 μ

m after the second ion exchange step.

72. The method of claim 55, wherein the first ion exchange step produces a compressive stress profile having a first portion a extending from the surface to a depth d_a and a slope m_a, wherein the depth d_a is equal to the depth of compression and 2 MPa/μ

m≦

m_a≦

8 MPa/μ

m.

73. The method of claim 55, wherein the second ion exchange step produces a compressive stress profile comprising:

a. a first portion a extending from the surface to a depth d_a and having a slope m_a, wherein 3 μ

m≦

d_a≦

8 μ

m and 40 MPa/μ

m≦

m_a≦

200 MPa/μ

m; and

b. a second portion b extending from d_a to up to the depth of compression DOC and having a slope m_b, wherein 2 MPa/μ

m≦

m_b≦

8 MPa/μ

m.