Alkali-free glass
An alkali-free glass includes, in mol % in terms of oxides: SiO 2 : 63-75%; Al 2 O 3 : 10-16%; B 2 O 3 : 0-5%; MgO: 0.1-15%; CaO: 0.1-12%; SrO: 0-8%; and BaO: 0-6%. [MgO]/[CaO] is 1.5 or smaller. A value of Formula (A) is 82.5 or larger. A value of Formula (B) is 690 or larger and 800 or smaller. A value of Formula (C) is 100 or smaller. A value of Formula (D) is 20 or smaller. The alkali-free glass has a Young's modulus of 83 GPa or larger and a surface devitrification viscosity η c of 10 4.2 dPa·s or higher.
1 . An alkali-free glass, comprising, in mol % in terms of oxides:
SiO 2 : 63-75%,
Al 2 O 3 : 10-16%;
B 2 O 3 : 1.5 to 5%;
MgO: 0.1-15%;
CaO: 0.1-12%;
SrO: 0-3%; and
BaO: 0-6%,
wherein:
[MgO]/[CaO] is 1.5 or smaller;
a value of Formula (A) is 82.5 or larger, Formula (A) being 1.131[SiO 2 ]+1.933[Al 2 O 3 ]+0.362[B 2 O 3 ]+2.049[MgO]+1.751[CaO]+1.471[SrO]+1.039[BaO]-48.25;
a value of Formula (B) is in a range of 690 to 800, Formula (B) being 35.59[SiO 2 ]+37.34[Al 2 O 3 ]+24.59[B 2 O 3 ]+31.13[MgO]+31.26[CaO]+30.78[SrO]+31.98[BaO]-2761;
a value of Formula (C) is 100 or smaller, Formula (C) being −9.01[SiO 2 ]+36.36[Al 2 O 3 ]+5.7[B 2 O 3 ]+5.13[MgO]+17.25[CaO]+7.65[SrO]+10.58[BaO];
a value of Formula (D) is 12 or smaller, Formula (D) being −0.731 [SiO 2 ]+1.461[Al 2 O 3 ]−0.157[B 2 O 3 ]+1.904[MgO]+3.36[CaO]+3.411[SrO]+1.723[BaO]+(−3.318[MgO][CaO]−1.675[MgO][SrO]+1.757[MgO][BaO]+4.72[CaO][SrO]+2.094[CaO][BaO]+1.086[SrO][BaO])/([MgO]+[CaO]+[SrO]+[BaO]); and
the alkali-free glass has a Young's modulus of 83 GPa or larger and a surface devitrification viscosity η c of 10 4.2 dPa·s or higher.
2 . The alkali-free glass according to claim 1 , further comprising:
at least one selected from the group consisting of Li 2 O, Na 2 O, and K 2 O in an amount of greater than 0% to 0.2% in total in mole % in terms of oxides.
3 . The alkali-free glass according to claim 1 , further comprising:
F in an amount of greater than 0 mol % to 1.5 mol %.
4 . The alkali-free glass according to claim 1 , further comprising:
SnO 2 in an amount of greater than 0% to 0.5% in mol % in terms of oxides.
5 . The alkali-free glass according to claim 1 , further comprising:
ZrO 2 in an amount of greater than 0% to 0.09% in mol % in terms of oxides.
6 . The alkali-free glass according to claim 1 , wherein a value of Formula (B) is in a range of 1.50 to 5.50, Formula (E) being 4.379[SIO 2 ]+5.043[Al 2 O 3 ]+4.805[B 2 O 3 ]+4.828[MgO]+4.968[CaO]+5.051[SrO]+5.159[BaO]−453.
7 . The alkali-free glass according to claim 1 , wherein the alkali-free glass has a strain point of 690° C. or higher.
8 . The alkali-free glass according to claim 1 , wherein the alkali-free glass has a density of 2.8 g/cm 3 or lower and an average thermal expansion coefficient in 50-350° C. of 30×10 −7 /° C. to 45× 10 −7 /° C.
9 . The alkali-free glass according to claim 1 , wherein the alkali-free glass has a temperature T 2 at which a glass viscosity becomes 10 2 dPa·s of 1800° C. or lower and a temperature T 4 at which the glass viscosity becomes 10 4 dPa·s of 1400° C. or lower.
10 . The alkali-free glass according to claim 1 , wherein the alkali-free glass has an internal devitrification temperature of 1320° C. or lower.
11 . The alkali-free glass according to claim 1 , wherein the alkali-free glass has an internal devitrification viscosity η d of 10 4.4 dPa·s or higher.
12 . The alkali-free glass according to claim 1 , wherein the alkali-free glass has a crystal growth rate of 100 μm/hr or lower.
13 . The alkali-free glass according to claim 1 , wherein the alkali-free glass has a glass β-OH value in a range of 0.01 mm −1 to 0.5 mm −1 .
14 . The alkali-free glass according to claim 1 , wherein the alkali-free glass has an annealing point of 850° C. or lower.
15 . The alkali-free glass according to claim 1 , wherein the alkali-free glass has a compaction of 150 ppm or smaller when being held at 600° C. for 80 min.
16 . The alkali-free glass according to claim 1 , wherein the alkali-free glass has an equivalent cooling rate in a range of 5° C./min to 800° C./min.
17 . The alkali-free glass according to claim 1 , wherein the alkali-free glass has a sludge volume when the glass is subjected to an etching process of 30 ml or smaller.
18 . The alkali-free glass according to claim 1 , wherein the alkali-free glass has a photoelastic constant of 31 nm/MPa/cm or smaller.
19 . A glass plate, comprising:
the alkali-free glass of claim 1 ,
wherein the glass plate has a length of a side of 2400 mm or longer and a thickness of 1.0 mm or smaller.
20 . The glass plate according to claim 19 , wherein the glass plate is obtained by a float process or a fusion process.
21 . An alkali-free glass, comprising, in mol % in terms of oxides:
SiO 2 : 50-80%;
Al 2 O 3 : 8-20%;
Li 2 O+Na 2 O+K 2 O: 0-0.2%;
B 2 O 3 : 1.5 to 5%;
MgO: 0.1-15%:
CaO: 0.1-12%;
SrO: 0-3%;
P 2 O 5 : 0-1%; and
BaO: 3.5 to 6%,
wherein
[MgO]/[CaO] is 1.5 or smaller, and
the alkali-free glass has:
a Young's modulus of 83 GPa or larger;
a strain point of 690° C. or higher;
a temperature T 4 at which a glass viscosity becomes 10 4 dPa·s of 1400° C. or lower;
a temperature T 2 at which the glass viscosity becomes 10 2 dPa·s of 1800° C. or lower;
an internal devitrification temperature of 1320° C. or lower;
an internal devitrification viscosity η d of 10 4.4 dPa·s or higher;
a surface devitrification viscosity η c of 10 4.2 dPa·s or higher;
a crystal growth rate of 100 μm/hr or lower;
a density of 2.8 g/cm 3 or lower;
an average thermal expansion coefficient in 50-350° C. of 30×10 −7 to 45×10 −7 /° C.:
a value of Formula (A) is 82.5 or larger, Formula (A) being 1.131[SiO 2 ]+1.933[Al 2 O 3 ]+0.362[B 2 O 3 ]+2.049[MgO]+1.751[CaO]+1.471[SrO]+1.039[BaO]−48.25; and
a value of Formula (D) is 12 or smaller, Formula (D) being −0.731[SiO 2 ]+1.461[Al 2 O 3 ]−0.157[B 2 O 3 ]+1.904[MgO]+3.36[CaO]+3,411[SrO]+1.723[BaO]+(−3.318[MgO][CaO]−1.675[MgO][SrO]+1.757[MgO][BaO]+4.72[Cao][SrO]+2.094[CaO][BaO]+1.086[SrO][BaO])/([MgO]+[CaO]+[SrO]+[BaO]).
22 . The alkali-free glass according to claim 21 , further comprising:
B 2 O 3 in an amount of 1.5-4% in mol % in terms of oxides.
23 . The alkali-free glass according to claim 21 , further comprising, in mol % in terms of oxides:
CaO: 3-10%; and
SrO: 0.1-3%.
24 . The alkali-free glass according to claim 21 , further comprising, in mol % in terms of oxides:
B 2 O 3 : 1.5-4%;
CaO: 3-10%; and
SrO: 0.1-3%.
25 . The alkali-free glass according to claim 21 , further comprising:
F in an amount of greater than 0 mol % to 1.5 mol %.
26 . The alkali-free glass according to claim 21 , further comprising:
SnO 2 in an amount of greater than 0% to 0.5% in mol % in terms of oxides.
27 . The alkali-free glass according to claim 21 , further comprising:
ZrO 2 in an amount of greater than 0% to 0.09% in mol % in terms of oxides.
28 . The alkali-free glass according to claim 21 , wherein a value of Formula (A) is 85 or larger.
29 . The alkali-free glass according to claim 21 , wherein a value of Formula (B) is in a range of 690 to 800, Formula (B) being 35.59[SiO 2 ]+37.34[Al 2 O 3 ]+24.59[B 2 O 3 ]+31.13[MgO]+31.26[CaO]+30.78[SrO]+31.98[BaO]−2761.
30 . The alkali-free glass according to claim 21 , wherein a value of Formula (C) is 100 or smaller, Formula (C) being −9.01[SiO 2 ]+36.36[Al 2 O 3 ]+5.7[B 2 O 3 ]+5.13[MgO]+17.25[CaO]+7.65[SrO]+10.58[BaO].
31 . The alkali-free glass according to claim 21 , wherein a value of Formula (E) is in a range of 1.50 to 5.50, Formula (E) being 4.379[SiO 2 ]+5.043[Al 2 O 3 ]+4.805[B 2 O;]+4.828[MgO]+4.968[CaO]+5.051[SrO]+5.159[BaO]−453.
32 . The alkali-free glass according to claim 21 , wherein the alkali-free glass has a glass β-OH value in a range of 0.01 mm −1 to 0.5 mm −1 .
33 . The alkali-free glass according to claim 21 , wherein the alkali-free glass has an annealing point of 850° C. or lower.
34 . The alkali-free glass according to claim 21 , wherein the alkali-free glass has a compaction of 150 ppm or smaller when being held at 600° C. for 80 min.
35 . The alkali-free glass according to claim 21 , wherein the alkali-free glass has an equivalent cooling rate in a range of 5° C./min to 800° C./min.
36 . The alkali-free glass according to claim 21 , wherein the alkali-free glass has a sludge volume when the glass is subjected to an etching process of 30 ml or smaller.
37 . The alkali-free glass according to claim 21 , wherein the alkali-free glass has a photoelastic constant of 31 nm/MPa/cm or smaller.
38 . A glass plate, comprising:
the alkali-free glass of claim 21 ,
wherein the glass plate has a length of at least one side of 2400 mm or longer and a thickness of 1.0 mm or smaller.
39 . The glass plate according to claim 38 , wherein the glass plate is obtained by a float process or a fusion process.