US2019367404A1PendingUtilityA1
Glasses having improved ion exchangeability and thermal expansion
Est. expiryFeb 8, 2037(~10.5 yrs left)· nominal 20-yr term from priority
Inventors:Ulrich FotheringhamMichael SchwallUlrich PeuchertMiriam KunzeMartun HovhannisyanHolger Wegener
C03C 4/00C03B 23/0006C03C 3/04C03C 10/0054C03C 3/091C03C 3/093C03C 2203/10C03C 2203/50C03B 17/06
67
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Claims
Abstract
The present invention relates to glasses having a composition made up of base glasses. The glasses have a good chemical toughenability in combination with an advantageous coefficient of thermal expansion. Owing to their composition and the production process, the homogeneity of the properties of the glasses at their surface is high compared to the bulk glass. Furthermore, the fragility of the glasses is low, so that they can be processed to produce very thin glass articles.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A glass, comprising:
A constituent phase
min.
max.
Albite
10 mol %
40 mol %
Reedmergnerite
18 mol %
65 mol %
Potassium reedmergnerite
0 mol %
32 mol %
Grossular
0 mol %
10 mol %
Cordierite
0 mol %
10 mol %
Willemite
0 mol %
15 mol %
Silicon dioxide
0 mol %
50 mol %
Diboron trioxide
0 mol %
15 mol %
Titanium wadeite
0 mol %
24 mol %
Strontium feldspar
0 mol %
20 mol %
Celsian
0 mol %
20 mol %
wherein a coefficient of thermal expansion is calculated according to formulae:
E
pot
_
=
∑
i
=
1
n
c
i
·
∑
j
=
1
m
z
i
,
j
·
E
pot
,
j
∑
i
=
1
n
c
i
·
∑
j
=
1
m
z
i
,
j
,
(
2
)
wherein E pot is an average potential well depth, m is a number of cation types present, E pot,j is a potential well depth for a j-th cation type, and z j,i is a number of cations of the j-th type in an i-th constituent phase; and
CTE
=
(
5.185
(
kJ
Mol
)
E
pot
_
-
27.205
)
ppm
/
K
,
(
3
)
wherein CTE is the thermal coefficient of thermal expansion, such that said coefficient of thermal expansion is between 4.5 ppm/K and 6.5 ppm/K, and wherein a number of degrees of angular freedom per atom is calculated according to a formula:
f
=
∑
i
=
1
n
c
i
·
z
i
·
f
i
∑
i
=
1
n
c
i
·
z
i
,
(
1
)
wherein f is a number of degrees of angular freedom per atom, c i is a mole fraction of the i-th constituent phase, z i is a number of atoms per structural unit in the i-th constituent phase, f i is a number of degrees of angular freedom per atom in the i-th constituent phase, and “n” is a number of constituent phases, such that said number of degrees of angular freedom per atom is not more than 0.24.
2 . The glass according to claim 1 , wherein said glass has a proportion of albite of not more than 35 mol %.
3 . The glass according to claim 1 , wherein said glass has a composition which includes the following constituent phases:
Constituent phase
min.
max.
Albite
15 mol %
35 mol %
Reedmergnerite
18 mol %
45 mol %
Potassium
0 mol %
20 mol %
reedmergnerite
Grossular
1 mol %
9 mol %
Cordierite
0 mol %
10 mol %
Willemite
0 mol %
10 mol %
Silicon dioxide
0 mol %
40 mol %
Diboron trioxide
0 mol %
12 mol %
Titanium wadeite
0 mol %
20 mol %
Strontium feldspar
0 mol %
10 mol %
Celsian
0 mol %
10 mol %
4 . The glass according to claim 1 , wherein said glass has a composition which includes the following constituent phases:
Constituent phase
min.
max.
Albite
15 mol %
25 mol %
Reedmergnerite
30 mol %
40 mol %
Potassium
0 mol %
15 mol %
reedmergnerite
Grossular
1 mol %
8.5 mol %
Cordierite
0 mol %
5 mol %
Willemite
0 mol %
7.5 mol %
Silicon dioxide
0 mol %
40 mol %
Diboron trioxide
0 mol %
10 mol %
Titanium wadeite
0 mol %
18 mol %
Strontium feldspar
0 mol %
5 mol %
Celsian
0 mol %
5 mol %
5 . The glass according to claim 1 , wherein said glass has a composition which includes the following constituent phases:
Constituent phase
min.
max.
Albite
20 mol %
35 mol %
Reedmergnerite
25 mol %
35 mol %
Potassium
1 mol %
15 mol %
reedmergnerite
Grossular
1 mol %
8.5 mol %
Cordierite
0 mol %
5 mol %
Willemite
0 mol %
7.5 mol %
Silicon dioxide
0 mol %
30 mol %
Diboron trioxide
0 mol %
10 mol %
Titanium wadeite
0 mol %
18 mol %
Strontium feldspar
0 mol %
5 mol %
Celsian
0 mol %
5 mol %
6 . The glass according to claim 1 , wherein the glass is free of cordierite, titanium wadeite, strontium feldspar, and celsian.
7 . The glass according to claim 1 , wherein at least one of a proportion of reedmergnerite and a proportion of albite is greater than a proportion of silicon dioxide.
8 . The glass according to claim 1 , wherein the glass further includes a balance of further constituents which does not exceed a proportion of 5 mol %, and said balance does not contain the following oxides: SiO 2 , TiO 2 , B 2 O 3 , Al 2 O 3 , ZnO, MgO, CaO, BaO, SrO, Na 2 O, and K 2 O.
9 . The glass according to claim 8 , wherein said proportion of said balance is not more than 2 mol % of said glass.
10 . The glass according to claim 1 , wherein a sum of the proportions of albite, reedmergnerite and potassium reedmergnerite is at least 50 mol %.
11 . The glass according to claim 1 , wherein a proportion of reedmergnerite is greater than a proportion of potassium reedmergnerite.
12 . The glass according to claim 1 , wherein said coefficient of thermal expansion is at least 5 ppm/K.
13 . The glass according to claim 1 , wherein said number of degrees of angular freedom per atom is less than 0.23.
14 . The glass according to claim 1 , wherein said number of degrees of angular freedom per atom is less than 0.22.
15 . The glass according to claim 1 , wherein the coefficient of thermal expansion calculated according to formulae (2) and (3) in a surface glass corresponds to at least 50% of the coefficient of thermal expansion calculated according to formulae (2) and (3) in a bulk glass.
16 . The glass according to claim 1 , wherein the coefficient of thermal expansion calculated according to formulae (2) and (3) in a surface glass corresponds to not more than 99% of the coefficient of thermal expansion calculated according to formulae (2) and (3) in a bulk glass.
17 . A method for producing a glass, comprising the steps of:
melting a plurality of glass raw materials to produce a glass melt having a composition which includes:
A constituent phase
min.
max.
Albite
10 mol %
40 mol %
Reedmergnerite
18 mol %
65 mol %
Potassium reedmergnerite
0 mol %
32 mol %
Grossular
0 mol %
10 mol %
Cordierite
0 mol %
10 mol %
Willemite
0 mol %
15 mol %
Silicon dioxide
0 mol %
50 mol %
Diboron trioxide
0 mol %
15 mol %
Titanium wadeite
0 mol %
24 mol %
Strontium feldspar
0 mol %
20 mol %
Celsian
0 mol %
20 mol %
wherein a coefficient of thermal expansion is calculated according to formulae:
E
pot
_
=
∑
i
=
1
n
c
i
·
∑
j
=
1
m
z
i
,
j
·
E
pot
,
j
∑
i
=
1
n
c
i
·
∑
j
=
1
m
z
i
,
j
,
(
2
)
wherein E pot is an average potential well depth, m is a number of cation types present, E pot,j is a potential well depth for a j-th cation type, and z j,i is a number of cations of the j-th type in an i-th constituent phase; and
CTE
=
(
5.185
(
kJ
Mol
)
E
pot
_
-
27.205
)
ppm
/
K
,
(
3
)
wherein CTE is the thermal coefficient of thermal expansion, such that said coefficient of thermal expansion is between 4.5 ppm/K and 6.5 ppm/K, and wherein a number of degrees of angular freedom per atom is calculated according to a formula:
f
=
∑
i
=
1
n
c
i
·
z
i
·
f
i
∑
i
=
1
n
c
i
·
z
i
,
(
1
)
wherein f a number of degrees of angular freedom per atom, c i is a mole fraction of the i-th constituent phase, z i is a number of atoms per structural unit in the i-th constituent phase, f i is a number of degrees of angular freedom per atom in the i-th constituent phase, and “n” is a number of constituent phases, such that said number of degrees of angular freedom per atom is not more than 0.24;
moulding a glass article from the glass melt; and
cooling the glass article.
18 . The method according to claim 17 , wherein said glass melt has a proportion of albite of not more than 35 mol %.
19 . The method according to claim 17 , wherein at least one of a proportion of reedmergnerite and a proportion of albite is greater than a proportion of silicon dioxide.
20 . The method according to claim 17 , wherein the glass melt further includes a balance of further constituents which does not exceed a proportion of 5 mol %, and said balance does not contain the following oxides: SiO 2 , TiO 2 , B 2 O 3 , Al 2 O 3 , ZnO, MgO, CaO, BaO, SrO, Na 2 O, and K 2 O.Join the waitlist — get patent alerts
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