Chemically temperable glass sheet
The invention relates to a 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% 0≤K 2 O≤5% 3<Al 2 O 3 ≤5% 0<CaO<4.5% 5≤MgO≤12%; and comprising the following: 0.88≤[MgO/(MgO+CaO)]<1. The invention corresponds to an easy chemically-temperable soda-silica type glass composition, which is more suited for mass production than aluminosilicate glass, and therefore is available at low cost, and with a base glass/matrix composition that is close to or very similar to compositions already used in existing mass production.
1. A glass sheet having a boron and lithium-free glass composition comprising, in weight percentage, expressed with respect to a total weight of glass:
65≤SiO 2 ≤78%
5≤Na 2 O≤20%
0≤K 2 O≤3%
3<Al 2 O 3 ≤5%
0.12<CaO<1.33% and
4≤MgO≤12%;
wherein: 0.90≤[MgO/MgO+CaO]<0.97.
2. The glass sheet according to claim 1 , wherein the glass composition further 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. The glass sheet according to claim 1 , wherein the glass composition further 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. The glass sheet according to claim 1 , wherein the glass composition further 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. The glass sheet according to claim 1 , wherein 4≤Al 2 O 3 ≤5 wt %.
6. The glass sheet according to claim 1 , wherein 4≤Al 2 O 3 ≤4.5 wt %.
7. The glass sheet according to claim 4 , wherein 4.5≤Al 2 O 3 ≤5 wt %.
8. The glass sheet according to claim 1 , wherein 0≤K 2 O≤4 wt %.
9. The glass sheet according to claim 1 , wherein 0.92≤[MgO/(MgO+CaO)]≤0.97.
10. The glass sheet according to claim 1 , wherein 0.90≤[MgO/(MgO+CaO)]≤0.96.
11. The glass sheet according to claim 1 , which is chemically tempered.
12. The glass sheet according to claim 11 , wherein the glass sheet has a Depth of exchanged layer of greater than 10 microns.
13. The glass sheet according to claim 11 , wherein the glass sheet has a Depth of exchanged layer of greater than 15 microns.
14. The glass sheet according to claim 11 , wherein the glass sheet has a surface compressive stress of from 856 to 888 MPa.
15. An electronic device comprising the glass sheet of claim 1 .
16. A glass sheet having a boron and lithium-free glass composition comprising, in weight percentage, expressed with respect to a total weight of glass:
65≤SiO 2 ≤78%
5≤Na 2 O≤20%
0≤K 2 O<5%
3<Al 2 O 3 ≤5%
0.21<CaO<1.33% and
4≤MgO≤12%;
wherein: 0.90≤[MgO/MgO+CaO]<0.95.
17. The glass sheet according to claim 16 , wherein the glass composition further comprises total iron, expressed in the form of Fe 2 O 3 , in a content ranging from 0.002 to 0.06% by weight.
18. The glass sheet according to claim 16 , wherein 4≤Al 2 O 3 ≤5 wt %.
19. A glass sheet having a boron and lithium-free glass composition comprising, in weight percentage, expressed with respect to a total weight of glass:
65≤SiO 2 ≤78%
5≤Na 2 O≤20%
0≤K 2 O<2%
4<Al 2 O 3 ≤5%
0.19<CaO<1.11% and
6≤MgO≤10%;
wherein: 0.90≤[MgO/MgO+CaO]<0.97.
20. The glass sheet according to claim 9 , wherein 0.90≤[MgO/(MgO+CaO)]≤0.95.