Fused spinel-zirconia grains and refractory product obtained from said grains

Patent metadata

Field	Value
Publication number	US-10479730-B2
Application number	US-201615769272-A
Country	US
Kind code	B2
Filing date	Oct 19, 2016
Priority date	Oct 19, 2015
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

Fused grains, in which the grains include a matrix of the zirconia-spinel eutectic coating inclusions composed essentially of a zirconia phase or of a spinel phase, the grains exhibit the following overall chemical composition, as percentages by weight expressed in the form of oxides: more than 45.0% and less than 95.0% of ZrO 2 , more than 3.0% and less than 40.0% of Al 2 O 3 , more than 1.0% and less than 20.0% of MgO, wherein ZrO 2 , Al 2 O 3 and MgO together represent at least 95.0% of the weight of the grains.

First claim

The invention claimed is:

1. Fused grains, in which:
said grains comprise a matrix of a zirconia-spinel eutectic coating inclusions composed essentially of a zirconia phase or of a spinel phase,
said grains exhibit the following overall chemical composition, as percentages by weight expressed in the form of oxides:
more than 45.0% and less than 95.0% of ZrO 2 ,
more than 3.0% and less than 40.0% of Al 2 O 3 ,
more than 1.0% and less than 20.0% of MgO,

ZrO 2 , Al 2 O 3 and MgO together represent at least 95.0% of the weight of said grains.

2. The fused grains as claimed in claim 1 , the chemical composition of which comprises more than 68% by weight of ZrO 2 .

3. The fused grains as claimed in claim 1 , the chemical composition of which comprises less than 25% by weight of Al 2 O 3 .

4. Fused grains, in which:
said grains comprise a matrix of a zirconia-spinel eutectic coating inclusions composed essentially of a zirconia phase or of a spinel phase,
said grains exhibit the following overall chemical composition, as percentages by weight expressed in the form of oxides:
more than 45.0% and less than 95.0% of ZrO 2 ,
more than 3.0% and less than 40.0% of Al 2 O 3 ,
more than 1.0% and less than 20.0% of MgO,

ZrO 2 , Al 2 O 3 and MgO together represent at least 95.0% of the weight of said grains, and in which the Al 2 O 3 /MgO ratio by weight is between 1.0 and 5.0.

5. The fused grains as claimed in claim 1 , in which ZrO 2 , Al 2 O 3 and MgO together represent more than 98.0% of the weight of said grains.

6. The fused grains as claimed in claim 1 , additionally comprising, on the basis of the oxide, more than 0.2% and less than 4% by weight of Y 2 O 3 .

7. The fused grains as claimed in claim 1 , additionally comprising, on the basis of the oxide, more than 0.2% and less than 4% by weight of CaO.

8. The fused grains as claimed in claim 1 , in which more than 50% of the inclusions essentially composed of zirconium oxide exhibit a greater dimension of less than 500 micrometers.

9. The fused grains as claimed in claim 1 , in which the spinel phase represents between 5% and 50% by weight of said grains.

10. The fused grains as claimed in claim 1 , in which the ZrO 2 -spinel eutectic represents between 10% and 80% by volume of said grains.

11. A refractory ceramic material or product obtained by sintering or consolidation of fused grains, or of a mixture of starting materials comprising fused grains, as claimed in claim 1 .

12. A method comprising manufacturing a refractory material with fused grains, in which:
said grains comprise a matrix of a zirconia-spinel eutectic coating inclusions composed essentially of a zirconia phase or of a spinel phase,
said grains exhibit the following overall chemical composition, as percentages by weight expressed in the form of oxides:
more than 45.0% and less than 95.0% of ZrO 2 ,
more than 3.0% and less than 40.0% of Al 2 0 3 ,
more than 1.0% and less than 20.0% of MgO,

ZrO 2 , Al 2 O 3 and MgO together representing at least 95.0% of the weight of said grains.

13. The method as claimed in claim 12 , wherein the refractory material is a refractory material for metallurgy.

14. The method as claimed in claim 12 , wherein said refractory material is obtained by sintering starting materials comprising said fused grains or consisting of said fused grains.

15. The method as claimed in claim 12 , wherein said refractory material is obtained by consolidation of starting materials comprising said fused grains or consisting of said fused grains.

16. The method as claimed in claim 12 , wherein said refractory material is obtained by sintering or consolidation of starting materials comprising a powder of zirconia and a powder of said fused grains, said powder of zirconia and said powder of fused grains together representing more than 90% by weight of said starting materials.

17. The fused grains as claimed in claim 4 , in which the Al 2 O 3 /MgO ratio by weight is between 1.5 and 3.0.

Assignees

• Saint Gobain Ct Recherches

Inventors

• Raffy Stéphane
• Nahas Nabil

Classifications

• C04B2235/762

  Cubic symmetry, e.g. beta-SiC · CPC title

• C04B35/117 Primary

  Composites · CPC title

• C04B35/18

  rich in aluminium oxide · CPC title

• C04B35/66

  Monolithic refractories or refractory mortars, including those whether or not containing clay {(making or repairing of linings F27D1/16)} · CPC title

• C04B2235/765

  Tetragonal symmetry · CPC title