Alkali-doped and alkali-free boroaluminosilicate glass
Alkali-doped boroaluminosilicate glasses are provided. The glasses include the network formers SiO 2 , B 2 O 3 , and Al 2 O 3 . The glass may, in some embodiments, have a Young's modulus of less than about 65 GPa and/or a coefficient of thermal expansion of less than about 40×10 −7 /° C. The glass may be used as a cover glass for electronic devices, a color filter substrate, a thin film transistor substrate, or an outer clad layer for a glass laminate.
1. A glass, the glass comprising: from about 50 mol % to about 70 mol % SiO 2 ; from greater than 6 mol % to 10 mol % Al 2 O 3 ; from 18 mol % to 30 mol % B 2 O 3 ; up to about 5 mol % MgO; up to about 10 mol % CaO; up to about 5 mol % SrO, and 0 mol % BaO, wherein MgO+CaO+SrO≦Al 2 O 3 , and wherein a sum of alkali metal oxide modifiers is less than or equal to about 1 mol %.
2. The glass of claim 1 , wherein the glass has a Young's modulus of less than about 65 GPa.
3. The glass of claim 2 , wherein the Young's modulus is less than 60 GPa.
4. The glass of claim 1 , wherein the glass has a coefficient of thermal expansion of less than about 40×10 −7 /° C.
5. The glass of claim 4 , wherein the coefficient of thermal expansion is less than about 35×10 −7 /° C.
6. The glass of claim 1 , wherein the glass further comprises at least one fining agent.
7. The glass of claim 6 , wherein the at least one fining agent comprises at least one of SnO 2 , CeO 2 , As 2 O 3 , Sb 2 O 5 , Cl − , and F − .
8. The glass of claim 7 , wherein the at least one fining agent comprises at least one of up to about 0.7 mol % SnO 2 , 0.7 mol % CeO 2 , up to about 0.5 mol % As 2 O 3 , and up to about 0.5 mol % Sb 2 O 3 .
9. The glass of claim 1 , wherein the glass comprises a total amount of MgO, CaO, and SrO that is greater than or equal to about 4 mol %.
10. The glass of claim 9 , wherein 4 mol %≦MgO+CaO+SrO≦Al 2 O 3 .
11. The glass of claim 1 , wherein the glass comprises: from about 55 mol % to about 70 mol % SiO 2 ; from greater than 6 mol % to 10 mol % Al 2 O 3 ; from 18 mol % to 30 mol % B 2 O 3 ; up to about 3 mol % MgO; up to about 10 mol % CaO; and up to about 3 mol % SrO.
12. The glass of claim 11 , wherein the glass comprises up to about 0.2 mol % SnO 2 .
13. The glass of claim 1 , wherein the glass forms a clad layer in a glass laminate, the glass laminate comprising a core glass having a coefficient of thermal expansion that is greater than a coefficient of thermal expansion of the clad layer.
14. The glass of claim 13 , wherein the clad layer is under a compressive stress of at least about 40 MPa.
15. The glass of claim 1 , wherein the glass has a liquidus viscosity of least 100 kpoise.
16. The glass of claim 15 , wherein the glass is down-drawable.
17. The glass of claim 1 , wherein the glass comprises up to about 0.5 mol % Fe 2 O 3 and up to about 0.1 mol % ZrO 2 .
18. The glass of claim 1 , wherein the glass is free of alkali metal oxide modifiers.
19. The glass of claim 1 , wherein the glass has a Knoop scratch threshold of at least 15 N.
20. The glass of claim 19 , wherein the glass has a Knoop scratch threshold of at least 20 N.
21. The glass of claim 1 , wherein the glass forms at least a portion of a color filter substrate, a thin film transistor substrate, a cover glass, or a touch interface.
22. A glass comprising SiO 2 , from 18 mol % to 30 mol % B 2 O 3 , from greater than 6 mol % to 10 mol % Al 2 O 3 , and 0 mol % BaO, wherein MgO+CaO+SrO≦Al 2 O 3 , wherein a sum of alkali metal oxide modifiers is less than or equal to about 1 mol % and the glass is substantially free of P 2 O 5 , and wherein the glass has at least one of a Young's modulus of less than 60 GPa and a coefficient of thermal expansion of less than about 40×10 −7 /° C.
23. The glass of claim 22 , wherein the coefficient of thermal expansion is less than about 35×10 −7 /° C.
24. The glass of claim 22 , wherein the glass comprises: from about 50 mol % to about 70 mol % SiO 2 ; from greater than 6 mol % to 10 mol % Al 2 O 3 ; from 18 mol % to 30 mol % B 2 O 3 ; up to about 5 mol % MgO; up to about 10 mol % CaO; and up to about 5 mol % SrO; and wherein the sum of alkali metal oxide modifiers is less than or equal to about 1 mol %.
25. The glass of claim 24 , wherein the glass further comprises at least one fining agent, the fining agent comprising at least one of SnO 2 , CeO 2 , As 2 O 3 , Sb 2 O 5 , Cl − , and F − .
26. The glass of claim 25 , wherein the at least one fining agent comprises at least one of up to about 0.7 mol % SnO 2 , up to about 0.5 mol % As 2 O 3 , and up to about 0.5 mol % Sb 2 O 3 .
27. The glass of claim 22 , wherein the glass comprises a total amount of MgO, CaO, and SrO that is greater than or equal to about 4 mol %.
28. The glass of claim 22 , wherein 4 mol %≦MgO+CaO+SrO≦Al 2 O 3 .
29. The glass of claim 22 , wherein the glass comprises: from about 55 mol % to about 70 mol % SiO 2 ; from greater than 6 mol % to 10 mol % Al 2 O 3 ; from 18 mol % to 30 mol % B 2 O 3 ; up to about 3 mol % MgO; up to about 10 mol % CaO; and up to about 3 mol % SrO and, optionally, at least one fining agent.
30. The glass of claim 29 , wherein the at least one fining agent comprises up to about 0.2 mol % SnO 2 .
31. The glass of claim 29 , wherein 4 mol %≦MgO+CaO+SrO≦Al 2 O 3 .
32. The glass of claim 22 , wherein the glass forms a clad layer in a glass laminate comprising a core glass, wherein the core glass has a coefficient of thermal expansion that is greater than a coefficient of thermal expansion of the clad layer.
33. The glass of claim 32 , wherein the clad layer is under a compressive stress of at least about 40 MPa.
34. The glass of claim 22 , wherein the glass forms at least a portion of a color filter substrate, a thin film transistor substrate, a cover glass, or a touch interface.
35. The glass of claim 22 , wherein the glass has a liquidus viscosity of at least 100 kpoise.
36. The glass of claim 35 , wherein the glass is down-drawable.
37. The glass of claim 22 , wherein the glass has a Knoop scratch threshold of at least 15 N.
38. The glass of claim 37 , wherein the glass has a Knoop scratch threshold of at least 20 N.
39. A glass laminate, the glass laminate comprising a core glass and a clad glass laminated onto an outer surface of the core glass, the clad glass comprising SiO 2 , from 18 mol % to 30 mol % B 2 O 3 , from greater than 6 mol % to 10 mol % Al 2 O 3 , and 0 mol % BaO, wherein MgO+CaO+SrO≦Al 2 O 3 , the clad glass is substantially free of P 2 O 5 , and a sum of alkali metal oxide modifiers in the clad glass is less than or equal to about 1 mol %, and wherein the clad glass has a first coefficient of thermal expansion of less than about 40×10 −7 /° C. and the core glass has a second coefficient of thermal expansion that is greater than the first coefficient of thermal expansion.
40. The glass laminate of claim 39 , wherein the first coefficient of thermal expansion is less than about 35×10 −7 /° C.
41. The glass laminate of claim 39 , wherein the clad glass comprises: from about 50 mol % to about 70 mol % SiO 2 ; from greater than 6 mol % to 10 mol % Al 2 O 3 ; from 18 mol % to 30 mol % B 2 O 3 ; up to about 5 mol % MgO; up to about 10 mol % CaO; up to about 5 mol % SrO; and, optionally, at least one fining agent, wherein the sum of alkali metal oxide modifiers is less than or equal to about 1 mol %.
42. The glass laminate of claim 41 , wherein the at least one fining agent comprises at least one of SnO 2 , CeO 2 , As 2 O 3 , Sb 2 O 5 , Cl − , and F − .
43. The glass laminate of claim 42 , wherein the at least one fining agent comprises at least one of up to about 0.7 mol % SnO 2 , up to about 0.5 mol % As 2 O 3 , and up to about 0.5 mol % Sb 2 O 3 .
44. The glass laminate of claim 39 , the clad glass comprises a total amount of MgO, CaO, and SrO that is greater than or equal to about 4 mol %.
45. The glass laminate of claim 39 , wherein the clad glass comprises: from about 55 mol % to about 70 mol % SiO 2 ; from greater than 6 mol % to 10 mol % Al 2 O 3 ; from 18 mol % to 30 mol % B 2 O 3 ; up to about 3 mol % MgO; up to about 10 mol % CaO; up to about 3 mol % SrO; and, and, optionally, at least one fining agent, wherein the sum of alkali metal oxide modifiers is less than or equal to about 0.5 mol %.
46. The glass laminate of claim 45 , wherein the at least one fining agent comprises about 0.2 mol % SnO 2 .
47. The glass laminate of claim 39 , wherein the clad glass is under a compressive stress of at least about 40 MPa.
48. The glass laminate of claim 39 , wherein the core glass comprises an alkali aluminosilicate glass.
49. The glass laminate of claim 39 , wherein the clad glass is free of alkali metal oxide modifiers.
50. The glass of claim 39 , wherein the clad glass has a Knoop scratch threshold of at least 15 N.
51. The glass of claim 50 , wherein the clad glass has a Knoop scratch threshold of at least 20 N.
52. The glass laminate of claim 39 , wherein the clad glass has a liquidus viscosity of at least about 70 kPoise.
53. A method of making a glass, the method comprising:
a. providing a glass melt, the glass melt comprising from about 50 mol % to about 70 mol % SiO 2 , from 18 mol % to 30 mol % B 2 O 3 , from greater than 6 mol % to 10 mol % Al 2 O 3 , up to about 5 mol % MgO, up to about 10 mol % CaO, up to about 5 mol % SrO, and 0 mol % BaO, wherein MgO+CaO+SrO≦Al 2 O 3 and a sum of alkali metal oxide modifiers in the glass melt is less than or equal to about 1 mol %; and
b. down-drawing the glass melt to form the glass.
54. The method of claim 53 , wherein down-drawing the glass melt comprises fusion-drawing the glass melt.
55. The method of claim 53 , wherein the glass melt is a clad glass melt, and wherein the method further comprises:
a. providing a core glass melt;
b. fusion-drawing the core glass melt to form a core glass; and
c. fusion-drawing the clad glass melt to form a clad layer glass surrounding the core glass, wherein the core glass has a coefficient of thermal expansion that is greater than that of the clad glass.
56. The method of claim 55 , wherein the clad layer is under a compressive stress of at least about 100 MPa.
57. The method of claim 53 , wherein the glass has a coefficient of thermal expansion of less than about 40×10 −7 /° C.
58. The method of claim 57 , wherein the coefficient of thermal expansion is less than about 35×10 −7 /° C.
59. The method of claim 53 , wherein the glass has a Young's modulus of less than about 65 GPa.
60. The method of claim 59 , wherein the Young's modulus is less than 60 GPa.
61. The method of claim 53 , wherein the glass has a liquidus viscosity of at least about 70 kPoise.
62. The method of claim 53 , wherein the glass comprises: at least one fining agent.
63. The method of claim 53 , wherein the glass comprises: from about 55 mol % to about 70 mol % SiO 2 ; from greater than 6 mol % to 10 mol % Al 2 O 3 ; from 18 mol % to 30 mol % B 2 O 3 ; up to about 3 mol % MgO; up to about 10 mol % CaO; up to about 3 mol % SrO; and, optionally, at least one fining agent, wherein the sum of alkali metal oxide modifiers is less than or equal to about 0.5 mol %.
64. The method of claim 62 , wherein the clad glass comprises a total amount of MgO, CaO, and SrO that is greater than or equal to about 4 mol %.
65. The method of claim 53 , wherein the glass is free of alkali metal oxide modifiers.
66. The glass of claim 22 , wherein the glass forms at least a portion of a color filter substrate, a thin film transistor substrate, a cover glass, or a touch interface.