Dielectric ceramic material

• US 6,995,106 B2
• Filed: 07/15/2002
• Issued: 02/07/2006
• Est. Priority Date: 07/16/2001
• Status: Expired due to Fees

• Current Assignee: NGK Spark PLUG Company Limited
• Original Assignee: NGK Spark PLUG Company Limited
• Inventors: Tosa, Akifumi, Matsumiya, Masahiko, Oba, Takashi, Itakura, Kazuhisa
• Primary Examiner(s): GROUP, KARL E
• Application Number:
  US10/194,941
• Publication Number:
  US 20030109374A1
• Time in Patent Office: 1,303 Days
• Field of Search: 501/135
• US Class Current: 501/135
• CPC Class Codes: C01G 33/006 Compounds containing, besides niobium, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01G 35/006 Compounds containing, besides tantalum, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01G 51/006 Compounds containing, besides cobalt, two or more other elements, with the exception of oxygen or hydrogen cobaltates C01G51/40
• CPC Class Codes: C01G 9/006 Compounds containing, besides zinc, two ore more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01P 2002/52 containing elements as dopants
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/74 by peak-intensities or a ratio thereof only
• CPC Class Codes: C01P 2004/50 Agglomerated particles
• CPC Class Codes: C01P 2006/10 Solid density
• CPC Class Codes: C04B 2235/3201 Alkali metal oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3203 Lithium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3251 Niobium oxides, niobates, tantalum oxides, tantalates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3258 Tungsten oxides, tungstates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3262 Manganese oxides, manganates, rhenium oxides or oxide-forming salts thereof, e.g. MnO
• CPC Class Codes: C04B 2235/3272 Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite
• CPC Class Codes: C04B 2235/3275 Cobalt oxides, cobaltates or cobaltites or oxide forming salts thereof, e.g. bismuth cobaltate, zinc cobaltite
• CPC Class Codes: C04B 2235/3284 Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
• CPC Class Codes: C04B 2235/421 Boron
• CPC Class Codes: C04B 35/495 : based on vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates
• CPC Class Codes: C04B 35/62655 : Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying
• CPC Class Codes: C04B 35/62695 : Granulation or pelletising devices for shaping artificial aggregates from ceramic mixtures B28B1/004
• CPC Class Codes: C04B 35/638 : Removal thereof

Abstract

A dielectric ceramic material is represented by the following compositional formula, (100-a)[Ba_u{(Zn_vCo_1-v)wNb_x}O_δ1]-a[M_yTa_zO_δ2], where M represents at least one species selected from K, Na, and Li. In one method, the dielectric material is produced by mixing raw material powders such that proportions by mol of component metals simultaneously satisfy the relations, 0.5≦a≦25; 0.98≦u≦1.03; 0≦v≦1; 0.274≦w≦0.374; 0.646≦x≦0.696; 0.5≦y≦2.5; and 0.8≦z≦1.2. The method further includes subjecting the resultant mixture to primary pulverization; calcining the resultant powder at 1,100-1,300° C., followed by wet secondary pulverization; drying the resultant paste; granulating; molding the resultant granules to thereby yield a compact; and firing the compact in air advantageously at 1,400-1,600° C.

Claims

1. A dielectric ceramic material comprising:

Ba, Nb, and Ta;

at least Co; and

at least one species selected from the group consisting of K, Na, and Li,

said ceramic material being represented by the compositional formula;

(100-a)[Ba_u{(Zn_vCo_1-v)_wNb_x}O<sub>δ

3</sub>]-a[M_yTa_zO<sub>δ

3</sub>],

where M represents at least one species selected from the group consisting of K, Na, and Li, and the following relations are satisfied simultaneously;

0.5≦

a≦

25;

0.98≦

u≦

1.03;

0.4≦

v≦

0.8 0.274≦

w≦

0.374;

0.646≦

x≦

0.696;

0.5≦

y≦

2.5; and

0.8≦

z≦

1.2.

2. A dielectric ceramic material of claim 1, wherein M is K.

3. A dielectric ceramic material of claim 1, wherein y and z satisfy the following relations:

1.0≦

y≦

2.0and 0.9≦

z≦

1.1.

4. A dielectric ceramic material of claim 1, wherein a satisfies the following relation:

1≦

a≦

10.

5. A dielectric ceramic material represented by the compositional formula:

(100-a)[Ba_u{(Zn_vCo_1-v)_wNb_x}O₃]-a[M_yTa_zO₃], wherein the ceramic material includes Co and wherein M represents at least one species selected from the group consisting of K, Na, and Li, said ceramic material being produced by mixing raw material powders such that proportions by mol of component metals simultaneously satisfy the relations;

0.5≦

a≦

25;

0.98≦

u≦

1.03 0.4≦

v≦

0.8;

0.274≦

w≦

0.374;

0.646≦

x≦

0.696;

0.5≦

y≦

2.5; and

0.8≦

z≦

1.2;

molding the resultant mixture powder, to thereby yield a compact; and

firing the compact to produce a ceramic material having dielectric constant ε

r between 30 and 37.

6. The dielectric ceramic material of claim 5, wherein M is K.

7. The dielectric ceramic material of claim 5, wherein y and z satisfy the following relations:

1.0≦

y≦

2.0 and 0.9≦

z≦

1.1.

8. The dielectric ceramic material of claim 5, wherein a satisfies the following relation:

1≦

a≦

10.

9. A dielectric ceramic material comprising:

Ba, Nb, and Ta;

at least Co;

at least one species selected from the group consisting of K, Na, and Li; and

Mn or W,

wherein Mn and W are contained in amounts of 0.02-3 mass % as reduced to MnO₂ and 0.02-4.5 mass % as reduced to WO₃, respectively, on the basis of 100 parts by mass of the following composition (100-a)[Ba_u{(Zn_vCo_1-v)_wNb_x}O₃]-a[M_yTa_zO₃], wherein M represents at least one species selected from the group consisting of K, Na, and Li, and the following relations are satisfied simultaneously;

0.5≦

a≦

25;

0.98≦

u≦

1.03;

0.4≦

v≦

0.8;

0.274≦

w≦

0.374;

0.646≦

x≦

0.696;

0.5≦

y≦

2.5; and

0.8≦

z≦

1.2, said dielectric ceramic material having a dielectric constant ε

r between 30 and 37.

10. The dielectric ceramic material of claim 9, wherein said ceramic material has a percent maintenance of unloaded quality coefficient as expressed by percentage of unloaded quality coefficient measured at 125°

C. with respect to that measured at 25°

C. of at least 70%.

15. The dielectric material produced by the method of claim 10.

16. The dielectric ceramic material of claim 15, wherein M is K.

11. A method for manufacturing a dielectric ceramic material, said method comprising the steps of:

mixing raw material powders which will comprise the dielectric ceramic material represented by the compositional formula;

(100-a)[Ba_u{(Zn_vCo_1-v)_wNb_x}O₃]-a[M_yTa_zO₃], wherein the material includes Co and wherein M represents at least one species selected from the group consisting of K, Na, and Li, such that proportions by mol of component metals simultaneously satisfy the relations;

0.5≦

a≦

25;

0.98≦

u≦

1.03;

0.4≦

v≦

0.8;

0.274≦

w≦

0.374;

0.646≦

x≦

0.696;

0.5≦

y≦

2.5; and

0.8≦

z≦

1.2;

molding the resultant mixture powder, to thereby yield a compact; and

firing the compact to thus produce a dielectric ceramic material having dielectric constant ε

r between 30 and 37.

12. A method of claim 11, wherein M is K.

14. The method of claim 11, wherein a satisfies the relation:

1≦

a≦

10.

13. The method of 11, wherein y and z satisfy the relations:

1.0≦

y≦

2.0 and 0.9≦

z≦

1.1.

17. The dielectric ceramic material of 15, wherein y and z satisfy the relations:

1.0≦

y≦

2.0 and 0.9≦

z≦

1.1.

18. The dielectric ceramic material of 15, wherein a satisfies the relation:

1≦

a≦

10.