Beta-alumina-based sintered compact and its production method

Patent metadata

Field	Value
Publication number	US-9735446-B2
Application number	US-201414473363-A
Country	US
Kind code	B2
Filing date	Aug 29, 2014
Priority date	Feb 29, 2012
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

To provide a dense beta-alumina-based sintered compact having a high ionic conductivity as a solid electrolyte by firing at a low temperature to suppress the volatilization of Na 2 O and its production method.
By adding RNbO 3 which is a material having a low melting point to a beta-alumina powder, followed by firing, it is possible to obtain a beta-alumina-based sintered compact having a low firing temperature and containing, as the main component, dense β″ alumina crystals which are free from anomalous grain growth during the firing process.

First claim

What is claimed is:

1. A beta-alumina-based sintered compact, comprising:
a beta-alumina crystalline phase having Na 2 O and Al 2 O 3 as main components; and
an RNbO 3 crystalline phase;
wherein R is at least one element selected from the group consisting of Li, Na, and K.

2. The beta-alumina-based sintered compact according to claim 1 , wherein the beta-alumina crystalline phase comprises a β″ alumina crystalline phase.

3. The beta-alumina-based sintered compact according to claim 1 , wherein R is Na.

4. The beta-alumina-based sintered compact according to claim 1 , comprising NiO as a component.

5. The beta-alumina-based sintered compact according to claim 4 , wherein a chemical composition of the beta-alumina-based sintered compact, based on oxides, is:
from 8 to 15 mass % of Na 2 O;
from 5 to 30 mass % of Nb 2 O 5 ;
from 1 to 10 mass % of NiO; and
a remainder of Al 2 O 3 .

6. A method for producing the beta-alumina-based sintered compact as defined in claim 1 , comprising:
mixing a beta-alumina powder and an RNbO 3 powder; and
molding and firing the mixture;
wherein R is at least one element selected from the group consisting of Li, Na, and K.

7. The method for producing the beta-alumina-based sintered compact according to claim 6 , wherein firing the mixture comprises firing at a temperature of less than 1450° C.

8. The method for producing the beta-alumina-based sintered compact according to claim 6 , wherein the beta-alumina powder comprises β″ alumina.

9. The method for producing the beta-alumina-based sintered compact according to claim 6 , wherein R is Na.

10. The method for producing the beta-alumina-based sintered compact according to claim 6 , wherein the beta-alumina powder comprises NiO.

11. The method for producing the beta-alumina-based sintered compact according to claim 10 , wherein a chemical composition of the beta-alumina-based sintered compact, based on oxides, is
from 8 to 15 mass % of Na 2 O;
from 5 to 30 mass % of Nb 2 O 5 ;
from 1 to 10 mass % of NiO; and
a remainder of Al 2 O 3 .

12. A beta-alumina-based sintered compact, comprising:
as chemical components, based on oxides, Na 2 O and Al 2 O 3 ; and
as a crystalline phase, a beta alumina crystalline phase and an RNbO 3 crystalline phase;
wherein R is at least one element selected from the group consisting of Li, Na, and K.

13. The beta-alumina-based sintered compact according to claim 12 , wherein the beta-alumina crystalline phase comprises a β″ alumina crystalline phase.

14. The beta-alumina-based sintered compact according to claim 12 , wherein R is Na.

15. The beta-alumina-based sintered compact according to claim 12 , comprising NiO.

16. The beta-alumina-based sintered compact according to claim 15 , wherein a chemical composition of the beta-alumina-based sintered compact, based on oxides, is:
from 8 to 15 mass % of Na 2 O,
from 5 to 30 mass % of Nb 2 O 5 ;
from 1 to 10 mass % of NiO; and
a remainder of Al 2 O 3 .

Assignees

• Asahi Glass Co Ltd

Inventors

• Mitsui Akira

Classifications

• C04B2235/3255

  Niobates or tantalates, e.g. silver niobate · CPC title

• C04B2235/5427

  millimeter or submillimeter sized, i.e. larger than 0,1 mm · CPC title

• C04B2235/3251

  Niobium oxides, niobates, tantalum oxides, tantalates, or oxide-forming salts thereof · CPC title

• C04B35/113

  based on beta-aluminium oxide · CPC title

• H01M10/0562 Primary

  Solid materials · CPC title