EP0200573A2
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EP
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Dielectric ceramic composition with high dielectric constant and flat TC characteristics
Assignee: Tam Ceramics LLC
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Filing: 1986-05-02
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Granted: —
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Expires: 2006-05-02
Abstract
Abstract The present invention provides ceramic compositions for preparing multi-layer capacitors (MLCs) having high dielectric constants between about 3000 and 4700 and stable temperature coefficients (TC) prepared from high purity barium titanate, niobium pentoxide and cobalt oxide.
Inventors
- 👤 Mike S.H Chu
- 👤 Charles E. Hodgkins
- 👤 Terrence C. Dean
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 16:43
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/46; C04B35/462; C04B35/465; C04B35/468; C04B35/4682; C04B35/48; H; H01; H01G; H01G4/00; H01G4/002; H01G4/018; H01G4/06; H01G4/08; H01G4/12; H01G4/1209; H01G4/1218; H01G4/1227
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
43 words
A ceramic composition, comprising: about 97.70 - 98-99 % wt barium titanate; about 0.85 - 1.69% wt of niobium pentoxide; about 0.09 - 1.20% wt of cobalt oxide; and a wt ratio of niobium pentoxide to cobalt oxide of about 3.30 to 18.00.
Claim 2
Dependent Claim
43 words
A ceramic composition, comprising: about 97.70 - 98-99 % wt barium titanate; about 0.85 - 1.69% wt of niobium pentoxide; about 0.09 - 1.20% wt of cobalt oxide; and a wt ratio of niobium pentoxide to cobalt oxide of about 3.30 to 18.00.
Claim 3
Dependent Claim
36 words
The ceramic composition of claim 1, wherein: the barium titanate has a purity of about 99.0%, a BaO/TiO 2 stoichiometric ratio of about 0.950 to 0.995; and an average particle size of about 0.90µm to 1.30µm.
Claim 4
Dependent Claim
47 words
The ceramic composition of claim 2, wherein: the niobium pentoxide has a purity of about 99.0% and a particle size of about 0.5 to 0.9µm; and the cobalt oxide has a purity of about 70% to 74% and a particle size of less than about 1.0 µm.
Claim 5
Dependent Claim
41 words
The ceramic composition of claim 1 wherein: the barium titanate comprises about 98.82 % wt; the niobium pentoxide comprises about 0.98% wt; the cobalt oxide comprises about 0.20% wt; and the niobium pentoxide to cobalt oxide weight ratio is about 4.90.
Claim 6
Dependent Claim
90 words
A ceramic composition for making MLCs having high dielectric constants and TC characteristics that vary no more than about + 15 percent from their reference value at 25°C over a temperature range of -55°C to 125°C, the composition comprising a mixture of: about 97.70 - 98.99 % wt barium titanate; about 0.85 - 1.69 % wt of niobium pentoxide; about 0.09 - 1.20 wt of cobalt oxide; having a weight ratio of niobium pentoxide to cobalt oxide of about 3.30 to 18.00; and the mixture dispersed in a binder composition.
Claim 7
Dependent Claim
90 words
A ceramic composition for making MLCs having high dielectric constants and TC characteristics that vary no more than about + 15 percent from their reference value at 25°C over a temperature range of -55°C to 125°C, the composition comprising a mixture of: about 97.70 - 98.99 % wt barium titanate; about 0.85 - 1.69 % wt of niobium pentoxide; about 0.09 - 1.20 wt of cobalt oxide; having a weight ratio of niobium pentoxide to cobalt oxide of about 3.30 to 18.00; and the mixture dispersed in a binder composition.
Claim 8
Dependent Claim
37 words
The ceramic composition of claim 5, wherein: the barium titanate has a purity greater than about 99.0%, the BaO/TiO 2 stoichiometric ratio is about 0.950 to 0.995, and an average particle size is about 0.90pm to 1.30µm.
Claim 9
Dependent Claim
47 words
The ceramic composition of claim 6, wherein: the niobium pentoxide has a purity of about 99.0% and a particle size of about 0.5 to 0.9µm; and the cobalt oxide has a purity of about 70% to 74% and a particle size of less than about 1.0 µm.
Claim 10
Dependent Claim
40 words
The ceramic composition of claim 5, wherein: the barium titanate comprises about 98.82% wt; the niobium pentoxide comprises about 0.98% wt; the cobalt oxide comprises about 0.20% wt; and the niobium pentoxide to cobalt oxide weight ratio is about 4.90.
Claim 11
Dependent Claim
32 words
A MLC prepared with the composition of any one of claims 1 thru 8 and cofired with at least one metal selected from the group consisting of silver, gold, platinum and palladium.
Claim 12
Independent Claim
90 words
A method for preparing MLCs having dielectric constants between about 3000 and 4700 and stable TC's which comprises the steps of: (a) forming a plurality of dielectric layers from a mixture comprising: about 97-70 - 98.99 % wt barium titanate; about 0.85 - 1.69 % wt of niobium pentoxide; about 0.09 - 1.20 % wt of cobalt oxide; and a wt ratio of niobium pentoxide to cobalt oxide of about 3.30 to 18.00; (b) compressing and firing the mixture; and (c) forming a plurality of electrodes between the dielectric layers.
Claim 13
Independent Claim
90 words
A method for preparing MLCs having dielectric constants between about 3000 and 4700 and stable TC's which comprises the steps of: (a) forming a plurality of dielectric layers from a mixture comprising: about 97-70 - 98.99 % wt barium titanate; about 0.85 - 1.69 % wt of niobium pentoxide; about 0.09 - 1.20 % wt of cobalt oxide; and a wt ratio of niobium pentoxide to cobalt oxide of about 3.30 to 18.00; (b) compressing and firing the mixture; and (c) forming a plurality of electrodes between the dielectric layers.
Claim 14
Dependent Claim
37 words
The method of claim 10, wherein: the barium titanate has a purity of about 99%; a BaO/TiO 2 stoichiometric ratio of about 0.950 to 0.995; and an average particle size of about 0.90 µm to 1.30 µm.
Claim 15
Dependent Claim
46 words
The method of claim 11, wherein: the niobium pentoxide has a purity of about 99.0% and a particle size of about 0.5 to 0.9µm; and the cobalt oxide has a purity of about 70% to 74% and a particle size of less than about 1.0 µm.
Claim 16
Dependent Claim
39 words
The method of claim 10, wherein: the barium titanate comprises about 98.82% wt; the niobium pentoxide comprises about 0.98% wt; the cobalt oxide comprises about 0.20% wt; and the niobium pentoxide to cobalt oxide weight ratio is about 4.90.
References Cited (Backward Citations)
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