Glass sheet capable of having controlled warping through chemical strengthening
A float glass sheet having a boron- and lithium-free glass composition comprising the following in weight percentage, expressed with respect to the total weight of glass: 65≤SiO 2 ≤78% 5≤Na 2 O≤20% 1≤K 2 O<8% 1≤Al 2 O 3 <6% 2≤CaO<10% 0≤MgO≤8%; K 2 O/(K 2 O+Na 2 O) ratio which is from 0.1 to 0.7; wherein the glass sheet has: 0.01 < ( Na 2 O ) air ( Na 2 O ) tin - 1.03 ≤ 3. The glass sheet may be a chemically-temperable soda-silica type glass composition suitable for mass production that shows reduced or controlled increased warping effect.
1. A float glass sheet comprising the following in weight percentage, expressed with respect to the total weight of glass:
65≤SiO 2 ≤78%;
5≤Na 2 O≤20%;
1≤K 2 O<8%;
1≤Al 2 O 3 <6%;
2≤CaO<10%;
0≤MgO≤8%; and
K 2 O/(K 2 O+Na 2 O) ratio of from 0.1 to 0.7,
wherein the glass sheet has:
0.01
<
(
Na
2
O
)
air
(
Na
2
O
)
tin
-
1.03
≤
3
,
and
wherein the glass sheet is boron- and lithium-free.
2. A float glass sheet according to claim 1 , wherein the composition comprises total iron (expressed in the form of Fe 2 O 3 ) in a content ranging from 0.002 to 1.7% by weight.
3. A float glass sheet according to claim 2 , wherein the composition comprises total iron (expressed in the form of Fe 2 O 3 ) in a content ranging from 0.002 to 0.06% by weight.
4. A float glass sheet according to claim 3 , wherein the composition comprises total iron (expressed in the form of Fe 2 O 3 ) in a content ranging from 0.002 to 0.02% by weight.
5. A float glass sheet according to claim 1 , wherein the composition comprises an alumina content such that 1≤Al 2 O 3 ≤4 wt %.
6. A float glass sheet according to claim 5 , wherein the composition comprises an alumina content such that : 2≤Al 2 O 3 ≤3 wt %.
7. A float glass sheet according to claim 1 , wherein the composition comprises : 5≤CaO<10 wt %.
8. A float glass sheet according to claim 1 , wherein the composition comprises : 1≤K 2 O<6 wt %.
9. A float glass sheet according to claim 1 , wherein the composition comprises a K 2 O/(K 2 O+Na 2 O) ratio of from 0.1 to 0.5.
10. A float glass sheet according to claim 1 , wherein the composition comprises a K 2 O/(K 2 O+Na 2 O) ratio of from 0.2 to 0.5.
11. A float glass sheet according to claim 1 wherein the composition comprises a K 2 O/(K 2 O+Na 2 O) ratio of from 0.2 to 0.4.
12. A float glass sheet according to claim 1 , wherein the glass sheet has:
(
Na
2
O
)
air
(
Na
2
O
)
tin
≤
1.
13. A float glass sheet according to claim 1 , wherein R (CS 465° C. /CS 420° C. ) is from 0.76 to 0.92.
14. A float glass sheet according to claim 1 , wherein the glass sheet has a thickness of less than 1.5 mm.
15. A float glass sheet according to claim 1 , wherein the glass sheet has a thickness of less than 0.7 mm.
16. A float glass sheet according to claim 1 , wherein the float glass sheet is chemically tempered.
17. An electronic device comprising the float glass sheet according to claim 16 .
18. An electronic device comprising the float glass sheet according to claim 1 .
19. A float glass sheet comprising the following in weight percentage, expressed with respect to the total weight of glass:
65≤SiO 2 ≤78%;
5≤Na 2 O≤20%;
1≤K 2 O<8%;
3≤Al 2 O 3 <6%;
2≤CaO<10%;
0≤MgO≤8%; and
K 2 O/(K 2 O+Na 2 O) ratio of from 0.1 to 0.7,
wherein the glass sheet has:
0.02
<
(
Na
2
O
)
air
(
Na
2
O
)
tin
-
1.03
≤
3
,
and
wherein the glass sheet is boron- and lithium-free.