Refractory object and process of forming a glass sheet using the refractory object

Patent metadata

Field	Value
Publication number	US-9902653-B2
Application number	US-201514984539-A
Country	US
Kind code	B2
Filing date	Dec 30, 2015
Priority date	Jan 11, 2012
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

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.

First claim

What is claimed is:

1. A refractory object comprising:
Al 2 O 3 at a content in a range of 10 wt % Al 2 O 3 to 94 wt % Al 2 O 3 ;
SiO 2 at a content of at least 1.1 wt % and no greater than 4 wt % SiO 2 ;
Y 2 O 3 at a content of at least 3 wt % and no greater than 8 wt % Y 2 O 3 .

2. The refractory object as recited in claim 1 , wherein the refractory object includes no greater than 1 wt % of an alkali metal oxide.

3. The refractory object as recited in claim 1 , wherein the refractory object comprises no greater than 0.3 wt % ZrO 2 .

4. The refractory object as recited in claim 1 , wherein the refractory object comprises at least 70 wt % Al 2 O 3 .

5. The refractory object as recited in claim 1 , wherein a fracture toughness of the refractory object is at least 2.1 MPa-m 1/2 .

6. The refractory object as recited in claim 1 , wherein the refractory object further comprises a silica phase.

7. The refractory object as recited in claim 6 , wherein a melting point of the silica phase is at least 1300° C.

8. The refractory object as recited in claim 7 , wherein the melting point of the silica phase is at least a sintering temperature used in forming the refractory object.

9. The refractory object as recited in claim 1 , wherein the refractory object includes a peripheral region disposed between an edge of the refractory object and the body portion and outside of the body portion.

10. The refractory object as recited in claim 1 , wherein the SiO 2 is provided as amorphous SiO 2 , crystalline SiO 2 , or a combination thereof.

11. The refractory object as recited in claim 1 , wherein the apparent porosity of the refractory object is no greater than 0.8 vol %.

12. The refractory object as recited in claim 1 , wherein the percentage of theoretical density of the refractory object is at least 91%.

13. The refractory object of recited claim 1 , wherein the creep rate of the refractory object is no greater than 5.0×10 −5 h −1 .

14. The refractory object as recited in claim 1 , comprising grains having an average size of at least 10 micrometers.

15. The refractory object as recited in claim 1 , comprising grains having an average size no greater than 500 micrometers.

Assignees

• Saint Gobain Ceramics

Inventors

• Citti Olivier
• Fourcade Julien P
• Kazmierczak Andrea L

Classifications

• C04B2235/95

  Products characterised by their size, e.g. microceramics · CPC title

• C04B35/1015 Primary

  containing refractory metal compounds other than those covered by C04B35/103 - C04B35/106 · CPC title

• C04B2235/72

  Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics · CPC title

• C04B2235/3215

  Barium oxides or oxide-forming salts thereof · CPC title

• C04B2235/3236

  Alkaline earth titanates · CPC title