High CTE potassium borosilicate core glasses and glass articles comprising the same
High CTE glass compositions and laminated glass articles formed from the same are described. In one embodiment, a glass composition may include from about 70 mol. % to about 80 mol. % SiO 2 , from about 0 mol. % to about 8 mol. % Al 2 O 3 , and from about 3 mol. % to about 10 mol. % B 2 O 3 as glass formers. The glass composition may further include alkali oxides such as from about 0 mol. % to about 2 mol. % Na 2 O and from about 10 mol. % to about 15 mol. % K 2 O. In addition, the glass composition may include from about 5 mol. % to about 6 mol. % of alkaline earth oxide. The alkaline earth oxide may include at least one of CaO, SrO, and BaO. However, the glass composition may be substantially free from MgO. The glass composition may be used in a laminated glass article, such as a laminated glass article formed by a fusion laminate process.
1. A glass composition comprising:
from about 70 mol. % to about 80 mol. % SiO 2 ;
from 0 mol. % to about 8 mol. % Al 2 O 3 ;
from about 3 mol. % to about 10 mol. % B 2 O 3 ;
from 0 mol. % to about 2 mol. % Na 2 O;
from about 10 mol. % to about 15 mol. % K 2 O; and
from 5 mol. % to 6 mol. % of SrO+BaO
the glass composition comprises a coefficient of thermal expansion greater than or equal to 75×10 −7 /° C. averaged over a temperature range from 20° C. to 300° C.;
the glass composition comprises a liquidus viscosity greater than or equal to 250 kPoise; and
the glass composition is substantially free from MgO and CaO.
2. The glass composition of claim 1 , wherein the glass composition comprises:
from about 73 mol. % to about 77 mol. % SiO 2 ;
from 0 mol. % to about 3 mol. % Al 2 O 3 ;
from about 4 mol. % to about 5 mol. % B 2 O 3 ; and
from about 11.5 mol. % to about 12.5 mol. % K 2 O.
3. The glass composition of claim 1 , wherein the glass comprises:
greater than or equal to about 1.5 mol. % SrO; and
from 0 mol. % to about 2 mol. % BaO.
4. The glass composition of claim 1 , wherein a concentration of Na 2 O is greater than or equal to about 0.1 mol. %.
5. The glass composition of claim 1 , wherein a concentration of K 2 O (mol. %) is greater than a sum of a concentration of B 2 O 3 (mol. %) and a concentration of Al 2 O 3 (mol. %).
6. The glass composition of claim 1 , wherein the glass composition is substantially free of BaO.
7. The glass composition of claim 1 , wherein the glass composition further comprises at least one of SnO 2 , As 2 O 3 , and Sb 2 O 3 as a fining agent.
8. The glass composition of claim 1 , wherein the glass composition is substantially free from heavy metals.
9. The glass composition of claim 1 , wherein the glass composition is free from MgO.
10. The glass composition of claim 1 , wherein the glass composition is free from CaO.
11. A glass article comprising:
a glass core layer disposed between a first glass cladding layer and a second glass cladding layer, wherein the glass core layer is formed from the glass composition of claim 1 .
12. The glass article of claim 11 , wherein the glass comprises:
greater than or equal to about 1.5 mol. % SrO; and
from 0 mol. % to about 2 mol. % BaO.
13. The glass article of claim 11 , wherein the glass core layer comprises:
from about 73 mol. % to about 77 mol. % SiO 2 ;
from 0 mol. % to about 3 mol. % Al 2 O 3 ;
from about 4 mol. % to about 5 mol. % B 2 O 3 ;
from 0 mol. % to about 2 mol. % Na 2 O; and
from about 11.5 mol. % to about 12.5 mol. % K 2 O.
14. The glass article of claim 11 , wherein Na 2 O is present in the glass core layer in a concentration greater than or equal to about 0.1 mol. %.
15. The glass article of claim 11 , wherein a concentration of K 2 O (mol. %) in the glass core layer is greater than a sum of a concentration of B 2 O 3 (mol. %) in the glass core layer and a concentration of Al 2 O 3 (mol. %) in the glass core layer.
16. The glass article of claim 11 , wherein the glass core layer is substantially free of BaO.
17. The glass article of claim 11 , wherein the glass core layer further comprises at least one of SnO 2 , As 2 O 3 , and Sb 2 O 3 as a fining agent.
18. The glass article of claim 11 , wherein:
the glass core layer has an average core coefficient of thermal expansion CTE core ; and
the first glass cladding layer and the second glass cladding layer have an average cladding coefficient of thermal expansion CTE clad which is less than the average core coefficient of thermal expansion CTE core .
19. The glass article of claim 11 , wherein the glass core layer is substantially free from heavy metals.
20. The glass article of claim 11 , wherein a first surface of the glass core layer is directly adjacent the first glass cladding layer, and wherein a second surface of the glass core layer is directly adjacent the second glass cladding layer.
21. The glass article of claim 11 , wherein a diffusive layer is disposed between at least one of the first glass cladding layer or the second glass cladding layer and the glass core layer, and the average coefficient of thermal expansion of the diffusive layer has a value between that of an average core coefficient of thermal expansion of the glass core layer and an average cladding coefficient of thermal expansion of the at least one of the first glass cladding layer or the second glass cladding layer.
22. An electronic device comprising the glass article of claim 11 .
23. An architectural pane comprising the glass article of claim 11 .
24. A vehicle comprising the glass article of claim 11 .
25. An appliance comprising the glass article of claim 11 .