Oxide ceramic and ceramic electronic component

Patent metadata

Field	Value
Publication number	US-9947460-B2
Application number	US-201615017784-A
Country	US
Kind code	B2
Filing date	Feb 8, 2016
Priority date	Aug 22, 2013
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

An oxide ceramic represented by the general formula [Sr 2−x Ba x Co 2−y (Zn u Ni 1−u ) y Fe 12−z Al z O 22 ]. In the formula, 0.7≤x≤1.3 and 0.8≤z≤1.2. y is 0≤y≤0.8 when 0.5≤u≤1.0 and is 0≤y≤1.6 when 0≤u≤0.5. y is preferably 0.4 or less. Further, a variable inductor as a ceramic electronic component has a component base body formed from the oxide ceramic.

First claim

The invention claimed is:

1. An oxide ceramic comprising:
a ferrite compound containing at least Sr, Ba, Co, and Fe,
wherein the Ba is contained in a form of substitution for some of the Sr, and x is 0.7 to 1.3 when a content of the Ba is expressed as x/2 in molar ratio with respect to a total of the Ba and the Sr,
at least either one element M of Zn and Ni is contained in a form of substitution for some of the Co, and when a content of the element M is expressed as y/2 in molar ratio with respect to a total of the element M and the Co,
y is 0.8 or less when the element M is the Zn and when the element M is combined so that a content of the Zn is equal to or more than a content of the Ni in molar ratio, or
y is 1.6 or less when the element M is the Ni and when the element M is combined so that the content of the Zn is less than the content of the Ni in molar ratio, and

Al is contained in a form of substitution for some of the Fe, and z is 0.8 to 1.2 when a content of the Al is expressed as z/12 in molar ratio with respect to a total of the Al and the Fe.

2. The oxide ceramic according to claim 1 , wherein the oxide ceramic has a hexagonal Y-type crystal structure.

3. The oxide ceramic according to claim 1 , wherein the ferrite compound is represented by a general formula [Sr 2−x Ba x Co 2−y (Zn u Ni 1−u ) y Fe 12−z Al z O 22 ], where 0≤y≤0.8 and 0.5≤u≤1.0.

4. The oxide ceramic according to claim 1 , wherein the ferrite compound is represented by a general formula [Sr 2−x Ba x Co 2−y (Zn u Ni 1−u ) y Fe 12−z Al z O 22 ], where 0≤y≤1.6 and 0≤u<0.5.

5. The oxide ceramic according to claim 2 , wherein the y is 0.4 or less.

6. The oxide ceramic according to claim 3 , wherein the y is 0.4 or less.

7. The oxide ceramic according to claim 4 , wherein the y is 0.4 or less.

8. The oxide ceramic according to claim 5 , wherein the oxide ceramic was heat treated in an air atmosphere.

9. The oxide ceramic according to claim 6 , wherein the oxide ceramic was heat treated in an air atmosphere.

10. The oxide ceramic according to claim 7 , wherein the oxide ceramic was heat treated in an air atmosphere.

11. The oxide ceramic according to claim 1 , wherein the oxide ceramic has a maximum value electromagnetic coupling coefficient in a substantial zero field magnetic field.

12. The oxide ceramic according to claim 1 , wherein the oxide ceramic is structured such that a polarity of electric polarization is reversed when a polarity of a magnetic field is reversed.

13. A ceramic electronic component comprising:
a component base body and
an external electrode on a surface of the component base body,
wherein the component base body is formed from the oxide ceramic according to claim 1 .

14. The ceramic electronic component according to claim 13 , further comprising a coil disposed around the component base body, wherein the coil has an inductance that depends on a magnetic permeability of the component base body.

15. The ceramic electronic component according to claim 14 , further comprising an internal electrode embedded in the component base body.

16. The ceramic electronic component according to claim 13 , further comprising an internal electrode embedded in the component base body.

17. The ceramic electronic component according to claim 13 , wherein the ferrite compound is represented by a general formula [Sr 2−x Ba x Co 2−y (Zn u Ni 1−u ) y Fe 12−z Al z O 22 ], where 0≤y≤0.8 and 0.5≤u≤1.0.

18. The ceramic electronic component according to claim 13 , wherein the ferrite compound is represented by a general formula [Sr 2−x Ba x Co 2−y (Zn u Ni 1−u ) y Fe 12−z Al z O 22 ], where 0≤y≤1.6 and 0≤u<0.5.

19. The ceramic electronic component according to claim 17 , wherein the y is 0.4 or less.

20. The ceramic electronic component according to claim 18 , wherein the y is 0.4 or less.

Assignees

• Murata Manufacturing Co

Inventors

• Hirose Sakyo
• Kimura Tsuyoshi

Classifications

• C04B35/26 Primary

  based on ferrites · CPC title

• C04B2235/3272

  Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite · CPC title

• C04B2235/767

  Hexagonal symmetry, e.g. beta-Si3N4, beta-Sialon, alpha-SiC or hexa-ferrites · CPC title

• H01F1/344

  Ferrites, e.g. having a cubic spinel structure (X2+O)(Y23+O3), e.g. magnetite Fe3O4 · CPC title

• C04B35/2666

  Other ferrites containing nickel, copper or cobalt · CPC title