Refractory object and process of forming a glass sheet using the refractory object
A refractory object can include at least approximately 10 wt % Al 2 O 3 and at least approximately 1 wt % SiO 2 . In an embodiment, the refractory object can include an additive. In a particular embodiment, the additive can include TiO 2 , Y 2 O 3 , SrO, BaO, CaO, Ta 2 O 5 , Fe 2 O 3 , ZnO, or MgO. The refractory object can include at least approximately 3 wt % of the additive. In an additional embodiment, the refractory object can include no greater than approximately 8 wt % of the additive. In a further embodiment, the creep rate of the refractory object can be at least approximately 1×10 −6 h −1 . In another embodiment, the creep rate of the refractory object can be no greater than approximately 5×10 −5 h −1 . In an illustrative embodiment, the refractory object can include a glass overflow trough or a forming block.
1. A refractory object comprising:
Al 2 O 3 at a content in a range of 70 wt % Al 2 O 3 to 94 wt % Al 2 O 3 ;
SiO 2 at a content of at least 1.1 wt % and not greater than 7 wt % SiO 2 ; and
an additive at a content of at least 0.2 wt % additive, wherein the additive includes SrO, Ta 2 O 5 , ZnO, or any combination thereof; and
wherein a creep rate of the refractory object is no greater than 1×10 −4 h −1 and an apparent porosity of the refractory object is not greater than 0.5 vol % for a total volume of the refractory object.
2. The refractory object as recited in claim 1 , wherein the creep rate of the refractory object is no greater than 5.0×10 −5 h −1 .
3. The refractory object as recited in claim 2 , wherein the creep rate of the refractory object is at least 1×10 −6 h −1 .
4. The refractory object as recited in claim 1 , wherein the percentage of the theoretical density of the refractory object is no greater than 95%.
5. The refractory object as recited in claim 1 , wherein the percentage of the theoretical density of the refractory object is at least 91%.
6. A refractory object comprising:
Al 2 O 3 at a content in a range of 70 wt % Al 2 O 3 to 94 wt % Al 2 O 3 ;
SiO 2 at a content of at least 1.1 wt % and not greater than 7 wt % SiO 2 ;
an additive at a content of at least 0.2 wt % additive, wherein the additive includes SrO, Ta 2 O 5 , ZnO, or any combination thereof;
an aluminum phase;
a silica phase; and
wherein the silica phase is substantially uniformly dispersed throughout the aluminum phase within a body portion of the refractory object and
an apparent porosity of the refractory object is not greater than 0.5 vol % for a total volume of the refractory object.
7. The refractory object as recited in claim 6 , wherein the refractory object includes no greater than 8 wt % of the additive.
8. The refractory object as recited in claim 7 , wherein the silica phase includes an aluminum silicate, a strontium silicate, or any combination thereof.
9. The refractory object as recited in claim 7 , wherein the refractory object includes no greater than 1 wt % of an alkali metal oxide.
10. The refractory object as recited in claim 6 , wherein at least 16% of the Al 2 O 3 in the refractory object is provided as reactive Al 2 O 3 .
11. The refractory object as recited in claim 10 , wherein no greater than 99% of the Al 2 O 3 in the refractory object is provided as reactive Al 2 O 3 .
12. The refractory object as recited in claim 6 , wherein the refractory object comprises no greater than 0.3 wt % ZrO 2 .
13. The refractory object as recited in claim 12 , wherein the refractory object comprises at least 0.03 wt % ZrO 2 .
14. The refractory object as recited in claim 6 , wherein the refractory object comprises at least 85 wt % Al 2 O 3 .
15. The refractory object as recited in claim 14 , wherein the refractory object includes no greater than 93 wt % Al 2 O 3 .
16. The refractory object as recited in claim 6 , wherein a fracture toughness of the refractory object is at least 2.1 MPa-m 1/2 .