Fluorescent glass ceramics and glasses with cerium and tin content
The invention relates to glass ceramics and glasses with cerium and tin content, which comprise the following components: Component wt.-% SiO 2 42.0 to 80.0 Al 2 O 3 0.1 to 42.0 Cerium, calculated as CeO 2 0.5 to 10.0 Tin, calculated as SnO 0.1 to 4.0 and which are suitable in particular for the preparation of dental restorations, the fluorescence properties of which largely correspond to those of natural teeth.
1. Glass ceramic with cerium and tin content, which comprises the following components:
Component
wt.-%
SiO 2
42.0 to 80.0
Al 2 O 3
0.1 to 42.0
Cerium, calculated as CeO 2
0.5 to 10.0
Tin, calculated as SnO
0.1 to 4.0
wherein the molar ratio of cerium, calculated as CeO 2 , to tin, calculated as SnO, lies in the range of from 10:1 to more than 1:1.
2. Glass ceramic according to claim 1 , which comprises 46.0 to 77.0 wt.-% SiO 2 .
3. Glass ceramic according to claim 1 , which comprises 0.3 to 39.0 wt.-% Al 2 O 3 .
4. Glass ceramic according to claim 1 , which comprises 0.7 to 7.5 wt.-% cerium, calculated as CeO 2 .
5. Glass ceramic according to claim 1 , which comprises 0.2 to 3.0 wt.-% tin, calculated as SnO.
6. Glass ceramic according to claim 1 , in which the molar ratio of cerium, calculated as CeO 2 , to tin, calculated as SnO, lies in the range of from 10:1 to 2:1.
7. Glass ceramic according to claim 1 , which comprises 0 to 2.0 wt.-% terbium, calculated as Tb 4 O 7 .
8. Glass ceramic according to claim 1 , which comprises 0 to 18.0 wt.-% Li 2 O.
9. Glass ceramic according to claim 1 , which comprises 0 to 10.0 wt.-% BaO.
10. Glass ceramic according to claim 1 , which comprises at least one of the following components in the specified amounts:
Component
wt.-%
SiO 2
46.0 to 77.0
Al 2 O 3
0.3 to 39.0
Cerium, calculated as CeO 2
0.7 to 7.5
Tin, calculated as SnO
0.2 to 3.0
Terbium, calculated as Tb 4 O 7
0 to 2.0
Li 2 O
0 to 18.0
Me I 2 O
0 to 13.0
Me II O
0 to 22.0
Me III 2 O 3
0 to 10.0
Me IV O 2
0 to 10.0
Me V 2 O 5
0 to 8.0
Me VI O 3
0 to 6.0
Fluorine
0 to 5.0,
wherein
Me I 2 O is selected from Na 2 O, K 2 O, Rb 2 O and/or Cs 2 O,
Me II O is selected from MgO, CaO, SrO and/or ZnO,
Me III 2 O 3 is selected from B 2 O 3 , Y 2 O 3 , La 2 O 3 , Ga 2 O 3 and/or In 2 O 3 ,
Me IV O 2 is selected from ZrO 2 and/or GeO 2 ,
Me V 2 O 5 is selected from P 2 O 5 , V 2 O 5 , Ta 2 O 5 and/or Nb 2 O 5 and
Me VI O 3 is selected from WO 3 and/or MoO 3 .
11. Glass ceramic material, which comprises the glass ceramic with cerium and tin content as defined in claim 1 .
12. Glass ceramic according to claim 1 , wherein the glass ceramic is present in the form of a powder, a granulate, a blank or a dental restoration.
13. A process of producing the glass ceramic according to claim 1 which process comprises melting suitable starting material, wherein the tin is used at least partially in divalent form.
14. Process for the preparation of the glass ceramic according to claim 1 , in which a glass which comprises the following components:
Component
wt.-%
SiO 2
42.0 to 80.0
Al 2 O 3
0.1 to 42.0
B 2 O 3
0 to 5.0
Cerium, calculated as Ce0 2
0.5 to 10.0
Tin, calculated as SnO
0.1 to 4.0
wherein the molar ratio of cerium, calculated as CeO 2 , to tin, calculated as SnO, lies in the range of from 10:1 to more than 1:1,
is subjected to at least one heat treatment at a temperature of from 700 to 950° C.
15. Process according to claim 14 , in which
(a) powder of the glass, optionally after the addition of further components, is pressed to form a powder compact, and
(b) the powder compact is subjected to a heat treatment at a temperature of from 700 to 950° C.,
or
(a′) melt of the glass is shaped to form a glass blank, and
(b′) the glass blank is subjected to a heat treatment at a temperature of from 700 to 900° C.
16. Process for setting the fluorescence of a glass or of a glass ceramic, which process comprises using the glass ceramic according to claim 1 as blending component.
17. The glass ceramic according to claim 1 , wherein the glass ceramic is used as a dental material.
18. Process for the preparation of a dental restoration, which process comprises giving the glass ceramic according to claim 1 the shape of the desired dental restoration by pressing, sintering or machining.