EP0159869A2
Expired / Lapsed
EP
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Ceramic compositoin for dielectric in multilayer capacitors
Assignee: Union Carbide Corp
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Filing: 1985-04-12
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Granted: —
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Expires: 2005-04-12
Abstract
Abstract Lead oxide-base material for multilayer ceramic capacitors are provided having high dielectric constant and insulation resistance over wide temperature range, e.g. 10°C to 85°C. The dielectric composition comprises by weight in the aggregate of one or more of the following oxides: Ge0 2 , Si0 2 , Bi 2 0 3 , CdO, ZnO, Al 2 O 3 , CuO and B 2 0 3 , chemically combined with at least 20% by weight of PbO, to form a sintering aid having a melting point of not higher than 775°C and a resistivity at 25°C of at least 10 13 ohm-cm, said dielectric composition having a total lead oxide content, as PbO, of from 64.32 to 66.20% and having an atomic ratio of Pb to the sum of Nb, Fe and Mg from 0.893 to 0.913 and a weight ratio of MgO to Fe 2 0 3 from 0.34 to 1.3.
Inventors
- 👤 Hyun Duk C/O Goldstar Electric Co. Ltd. Park
- 👤 Arthur English Brown
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 16:38
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/495; C04B35/497; H; H01; H01G; H01G4/00; H01G4/002; H01G4/018; H01G4/06; H01G4/08; H01G4/12; H01G4/1209; H01G4/1254
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
191 words
A lead oxide-base dielectric ceramic material having high dielectric constant and high insulation resistance which is capable of being formed from a mixture of oxide powders by sintering at temperatures in the range of 900 to 1050°C, said ceramic materials comprising by weight, 2.49 to 6.67% Fe 2 O 3 24.18 to 28.14% Nb 2 0 5 2.09 to 3.59% MgO 0.025 to 0.10% Mn0 2 0.20 to 1.50% in the aggregate of one of more of the following oxides: GeO 2 , SiO 2 , Bi 2 O 3 , CdO, ZnO, A1 2 0 3 , CuO and B203, chemically combined with at least 20% by weight of PbO, to form a sintering aid additive having a melting point of not more than 775 0 C, and a resistivity at 25°C of at least 10 13 ohm-cm, said dielectric composition having a total lead oxide content, as PbO of from 64.32 to 66.20% and having an atomic ratio of Pb to the sum of Nb, Fe and Mg of from 0.893 to 0.913 and the weight ratio of MgO to Fe 2 O 3 is from 0.34 to 1.3.
Claim 2
Dependent Claim
191 words
A lead oxide-base dielectric ceramic material having high dielectric constant and high insulation resistance which is capable of being formed from a mixture of oxide powders by sintering at temperatures in the range of 900 to 1050°C, said ceramic materials comprising by weight, 2.49 to 6.67% Fe 2 O 3 24.18 to 28.14% Nb 2 0 5 2.09 to 3.59% MgO 0.025 to 0.10% Mn0 2 0.20 to 1.50% in the aggregate of one of more of the following oxides: GeO 2 , SiO 2 , Bi 2 O 3 , CdO, ZnO, A1 2 0 3 , CuO and B203, chemically combined with at least 20% by weight of PbO, to form a sintering aid additive having a melting point of not more than 775 0 C, and a resistivity at 25°C of at least 10 13 ohm-cm, said dielectric composition having a total lead oxide content, as PbO of from 64.32 to 66.20% and having an atomic ratio of Pb to the sum of Nb, Fe and Mg of from 0.893 to 0.913 and the weight ratio of MgO to Fe 2 O 3 is from 0.34 to 1.3.
Claim 3
Dependent Claim
34 words
A ceramic material in accordance with claim 1, wherein the dielectric constant is at least 10,000 and the insulation resistance is at least 10 12 ohm-cm at 25°C and 10 11 ohm-cm at 85°C.
Claim 4
Dependent Claim
42 words
A ceramic material in accordance with claim 1 or claim 2 which is characterised by a microstructure comprising a predominantly lead perovskite solid solution phase, as determined by X-ray diffraction, surrounding small discrete regions of metal oxide residues of sintering aid additive.
Claim 5
Independent Claim
164 words
A method of forming a lead-oxide based dielectric ceramic material which comprises milling and calcining PbO, Nb 2 O 5 , MgO, MnO 2 and Fe 2 O 3 or precursor salts in air at a temperature of from about 720 to 780°C and sintering the calcined mixture with an oxidic sintering aid material selected from one or more of GeO 2 , SiO 2 , Bi 2 O 3 , CdO, ZnO, Al 2 O 3 , CaO and B 2 O 3 in proportions such as to produce a sintered ceramic material containing the following composition:- 2.49 to 6.67% Fe 2 0 3 24.18 to 28.14% Nb 2 O 5 2.09 to 3.59% MgO 0.025 to 0.10% Mn0 2 64.32 to 66.20% P bO said ceramic material having an atomic ratio of Pb to the sum of Nb, Fe and Mg of from 0.893 to 0.913 and the weight ratio of MgO to Fe 2 O 3 being from 0.34 to 1.3.
Claim 6
Independent Claim
164 words
A method of forming a lead-oxide based dielectric ceramic material which comprises milling and calcining PbO, Nb 2 O 5 , MgO, MnO 2 and Fe 2 O 3 or precursor salts in air at a temperature of from about 720 to 780°C and sintering the calcined mixture with an oxidic sintering aid material selected from one or more of GeO 2 , SiO 2 , Bi 2 O 3 , CdO, ZnO, Al 2 O 3 , CaO and B 2 O 3 in proportions such as to produce a sintered ceramic material containing the following composition:- 2.49 to 6.67% Fe 2 0 3 24.18 to 28.14% Nb 2 O 5 2.09 to 3.59% MgO 0.025 to 0.10% Mn0 2 64.32 to 66.20% P bO said ceramic material having an atomic ratio of Pb to the sum of Nb, Fe and Mg of from 0.893 to 0.913 and the weight ratio of MgO to Fe 2 O 3 being from 0.34 to 1.3.
Claim 7
Dependent Claim
16 words
A method according to claim 4 in which the sintering temperature is from 965 to 1050°C.
Claim 8
Dependent Claim
24 words
A multilayer capacitor which comprises dielectric layers formed from the material claimed in any one of claims 1 to 3 separated by metal electrodes.
Claim 9
Dependent Claim
17 words
A capacitor according to claim 6 wherein the electrodes are formed from silver or an alloy thereof.
References Cited (Backward Citations)
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