US4767732A
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High dielectric constant ceramic material and method of manufacturing the same
Assignee: Toshiba Corp
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Filing: 1987-08-28
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Granted: 1988-08-30
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Expires: 2007-08-28
Abstract
Abstract To obtain a ceramic material having a high dielectric constant (K=2300 to 7000), a high insulation resistance (CR=4000 to 18000 ohmF), a low temperature dependence (±10%) to (±22, -33%) upon dielectric constant over a wide temperature range (-55 and +125° C.) and a relatively low sintering temperature (1000° C. to 1250° C.), BaTiO 3 powder at least 50 wt % of which is 0.7 to 3 μm in particle size) is mixed with another compound with perovskite structure mainly composed of oxides of Pb, Ba, Sr, Zn, Nb, Mg and Ti before sintering. Further, part of Ti of BaTiO 3 is substitutable with Zr or Sn, and part of Ba of BaTiO 3 is substitutable with Sr, Ca or Ce.
Inventors
- 👤 Osamu Furukawa
- 👤 Seiichi Yoshida
- 👤 Motomasa Imai
- 👤 Mitsuo Harata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:35
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/46; C04B35/462; C04B35/465; C04B35/468; C04B35/4682; C04B35/4684; C04B35/472; H; H01; H01G; H01G4/00; H01G4/002; H01G4/018; H01G4/06; H01G4/08; H01G4/12; H01G4/1209; H01G4/1218; H01G4/1227; H01G4/1254
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
67 words
A high dielectric constant ceramic material, consisting essentially of a composition expressed by the following formula (1-x)(Pb.sub.1-a-b Ba.sub.a Sr.sub.b). {(Zn.sub.1/3 Nb.sub.2/3).sub.1-c-d (Mg.sub.1/3 Nb.sub.2/3).sub.c Ti.sub.d }O.sub.3.xBaTiO.sub.3 where ______________________________________
0 ≦ a ≦ 0.35
0 ≦ b ≦ 0.35
0.01 ≦ a + b ≦ 0.35
0 ≦ c ≦ 0.9
0 < d ≦ 0.5
0 < c + d < 1.0
0.3 ≦ x ≦ 0.65.
______________________________________
Claim 2
Dependent Claim
67 words
A high dielectric constant ceramic material, consisting essentially of a composition expressed by the following formula (1-x)(Pb.sub.1-a-b Ba.sub.a Sr.sub.b). {(Zn.sub.1/3 Nb.sub.2/3).sub.1-c-d (Mg.sub.1/3 Nb.sub.2/3).sub.c Ti.sub.d }O.sub.3.xBaTiO.sub.3 where ______________________________________
0 ≦ a ≦ 0.35
0 ≦ b ≦ 0.35
0.01 ≦ a + b ≦ 0.35
0 ≦ c ≦ 0.9
0 < d ≦ 0.5
0 < c + d < 1.0
0.3 ≦ x ≦ 0.65.
______________________________________
Claim 3
Dependent Claim
33 words
The high dielectric constant ceramic material as set forth in claim 1, wherein at least 50 wt% of the BaTiO 3 has a particle size of 0.7 to 3 μm in particle size.
Claim 4
Dependent Claim
20 words
The high dielectric constant ceramic material as set forth in claim 1, wherein 0.3≦×≦0.5 and 0<c≦0.9 to lower sintering temperature.
Claim 5
Dependent Claim
21 words
The high dielectric constant ceramic material as set forth in claim 1, wherein 0.5≦×≦0.65 to reduce temperature dependence upon dielectric constant.
Claim 6
Dependent Claim
88 words
The high dielectric constant ceramic material as set forth in claim 1, wherein part of the Ti of BaTiO 3 is substituted for by Zr as expressed by the following formula (1-x)(Pb.sub.1-a-b Ba.sub.a Sr.sub.b). {(Zn.sub.1/3 Nb.sub.2/3).sub.1-c-d (Mg.sub.1/3 Nb.sub.2/3).sub.c Ti.sub.d }O.sub.3.xBa(Ti.sub.i-e Zr.sub.e)O.sub.3 where ______________________________________
0 ≦ a ≦ 0.35
0 ≦ b ≦ 0.35
0.01 ≦ a + b ≦ 0.35
0 ≦ c ≦ 0.9
0 < d ≦ 0.5
0 < e ≦ 0.06
0.3 ≦ x ≦ 0.65
0 < c + d < 1.0.
______________________________________
Claim 7
Dependent Claim
20 words
The high dielectric constant ceramic material as set forth in claim 5, wherein 0.3≦×≦0.5 and 0<c≦0.9 to lower sintering temperature.
Claim 8
Dependent Claim
21 words
The high dielectric constant ceramic material as set forth in claim 5, wherein 0.5≦×≦0.65 to reduce temperature dependence upon dielectric constant.
Claim 9
Dependent Claim
25 words
The high dielectric constant ceramic material as set forth in claim 1, wherein part of the Ti of BaTiO 3 is substituted for by Sn.
Claim 10
Dependent Claim
25 words
The high dielectric constant ceramic material as set forth in claim 1, wherein part of the Ba of BaTiO 3 is substituted for by Sr.
Claim 11
Dependent Claim
25 words
The high dielectric constant ceramic material as set forth in claim 1, wherein part of the Ba of BaTiO 3 is substituted for by Ca.
Claim 12
Dependent Claim
25 words
The high dielectric constant ceramic material as set forth in claim 1, wherein part of the Ba of BaTiO 3 is substituted for by Ce.
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