Glass composition for substrates
View Patent ↗A glass composition for substrates having good polishability while securing characteristics for FPD substrates, especially for PDP substrates, from which a glass substrate having excellent polishing workability and productivity can be obtained, is provided. A glass composition for substrates, which is characterized by comprising, as represented by mass % based on oxides, from 55 to 75% of SiO 2 , from 5 to 15% of Al 2 O 3 , from 0 to 4% of MgO, more than 5.5% and at most 12% of CaO, from 5 to 18% of SrO, from 0 to 13% of BaO, from 0.5 to 6% of ZrO 2 , from 0 to 10% of Na 2 O, from 0 to 15% of K 2 O, from 6 to 20% of Na 2 O+K 2 O, from 17 to 25% of MgO+CaO+SrO+BaO, and from 15 to 25% of CaO+SrO, as a glass matrix composition; and having a glass transition point of at least 600° C., an average thermal expansion coefficient of from 75×10 −7 to 90×10 −7 /° C. within a range of from 50 to 350° C., and an abrasion resistance of at least 98.
1. A glass composition, comprising, by mass % based on oxides:
from 55 to 75% of SiO 2 ,
from 5 to 15% of Al 2 O 3 ,
from 0 to 4% of MgO,
more than 5.5% and at most 12% of CaO,
from 5 to 18% of SrO,
from 0 to 13% of BaO,
from 0.5 to 6% of ZrO 2 ,
from 0 to 10% of Na 2 O,
from 0 to 15% of K 2 O,
from 6 to 20% of Na 2 O+K 2 O,
from 17 to 25% of MgO+CaO+SrO+BaO, and
from 15 to 25% of CaO+SrO,
wherein the composition is a glass matrix composition;
the composition is suitable for a substrate; and
the composition has a glass transition point of at least 600° C., an average thermal expansion coefficient of from 75×10 −7 to 90×10 −7 /° C. within a range of from 50 to 350° C., and an abrasion resistance of at least 98.
2. The composition of claim 1 , comprising, by mass % based on oxides:
from 55 to 65% of SiO 2 ,
from 5 to 10% of Al 2 O 3 ,
from 0 to 3.5% of MgO,
from 5.8 to 10% of CaO,
from 8 to 15% of SrO,
from 0 to 10% of BaO,
from 1 to 5% of ZrO 2 ,
from 2 to 10% of Na 2 O,
from 1 to 13% of K 2 O,
from 7 to 17% of Na 2 O+K 2 O,
from 18 to 25% of MgO+CaO+SrO+BaO, and
from 15 to 23% of CaO+SrO,
wherein the composition is a glass matrix composition.
3. The composition of claim 1 , comprising, by mass % based on oxides:
from 55 to 65% of SiO 2 ,
from 8 to 10% of Al 2 O 3 ,
from 0 to 3.5% of MgO,
from 5.8 to 10% of CaO,
from 8 to 15% of SrO,
from 0 to 10% of BaO,
from 1 to 5% of ZrO 2 ,
from 2 to 8% of Na 2 O,
from 1 to 10% of K 2 O,
from 7 to 14% of Na 2 O+K 2 O,
from 18 to 25% of MgO+CaO+SrO+BaO, and
from 15 to 23% of CaO+SrO,
wherein the composition is a glass matrix composition;
the composition further comprises from 0.06 to 0.15% of Fe 2 O 3 as an additive; and
the composition has an yellowing index value b* of at most 4 on a glass surface after a silver paste is applied to the glass surface, baked and removed.
4. The composition of claim 1 , which has a volume resistivity of at least 10 11 Ω·cm at 150° C.
5. The composition of claim 1 , wherein a BaO content is greater than 0.
6. The composition of claim 1 , wherein a BaO content is 0.
7. The composition of claim 1 , wherein a Li 2 O content is 0.
8. The composition of claim 1 , further comprising less than 1.5% B 2 O 3 , by mass % based on oxides.
9. The composition of claim 1 , wherein a content of SO 3 is less than or equal to 0.6% by mass based on oxides.
10. The composition of claim 1 , wherein a total content of SnO 2 , As 2 O 3 , Sb 2 O 3 , P 2 O 5 , F, and Cl is at most 2 mass %.
11. The composition of claim 1 , further comprising La 2 O 3 , TiO 2 , SnO 2 , ZnO, or a combination thereof, in a total content of at most 5 mass %, based on a mass of the glass matrix composition.
12. The composition of claim 1 , further comprising Fe 2 O 3 , CoO, NiO, Nd 2 O 3 , or a combination thereof, in a total amount of at most 3 mass %, based on a mass of the glass matrix composition.