Patent US4939108A successfully refreshed from Google Patents.
US4939108A
Expired / Lapsed
US
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Process for producing dielectric ceramic composition with high dielectric constant, low dissipation factor and flat TC characteristics
Assignee: Tam Ceramics LLC
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Filing: 1988-11-02
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Granted: 1990-07-03
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Expires: 2008-11-02
Abstract
Abstract The present invention provides ceramic compositions for preparing multi-layer capacitors, having high dielectric constants between about 4900 and 5400, dissipation factors below about 2.0%, high insulation resistance capacitance products and stable temperature coefficient characteristics, by a process of mixing a major oxide component with one or more precipitated dopant components.
Inventors
- 👤 Terrence C. Dean
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:33
CPC Classifications
B; B32; B32B; B32B18/00; C; C04; C04B; C04B35/00; C04B35/01; C04B35/46; C04B35/462; C04B35/465; C04B35/468; C04B35/4682; C04B2235/00; C04B2235/65; C04B2235/656; C04B2235/6567; C04B2237/00; C04B2237/30; C04B2237/32; C04B2237/34; C04B2237/345; C04B2237/346; C04B2237/50; C04B2237/68; C04B2237/70; C04B2237/704
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
84 words
A method for making dielectric ceramic having dopant particles uniformly dispersed therein comprising: dispersing 1 micron diameter major component particles in a liquid medium; precipitating 0.1 micron diameter particles of a first dopant from a liquid medium containing a precursor of the dopant; dispersing the first dopant particles throughout the major component particles so that the dopant particles are associated with the major component particles; dispersing particles of a second dopant, cobalt oxide, throughout the major component particles; removing the liquid medium; and sintering.
Claim 2
Independent Claim
84 words
A method for making dielectric ceramic having dopant particles uniformly dispersed therein comprising: dispersing 1 micron diameter major component particles in a liquid medium; precipitating 0.1 micron diameter particles of a first dopant from a liquid medium containing a precursor of the dopant; dispersing the first dopant particles throughout the major component particles so that the dopant particles are associated with the major component particles; dispersing particles of a second dopant, cobalt oxide, throughout the major component particles; removing the liquid medium; and sintering.
Claim 3
Dependent Claim
42 words
The method of claim 1 wherein the liquid medium containing the precursor of the first dopant is added to the liquid medium containing the major component particles; and wherein the first dopant is precipitated in the presence of the major component particles.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein the major component is barium titanate and the first dopant is niobium pentoxide.
Claim 5
Independent Claim
75 words
A method for making a ceramic powder having dopant particles uniformly dispersed therein, comprising the steps of: (a) preparing a liquid medium including a first dopant; (b) dispersing major component particles in the liquid medium; (c) precipitating the first dopant from the liquid medium in the presence of the major component particles so that a substantial portion of the dopant particles are uniformly dispersed about the major component particles; and (d) removing the liquid medium.
Claim 6
Independent Claim
75 words
A method for making a ceramic powder having dopant particles uniformly dispersed therein, comprising the steps of: (a) preparing a liquid medium including a first dopant; (b) dispersing major component particles in the liquid medium; (c) precipitating the first dopant from the liquid medium in the presence of the major component particles so that a substantial portion of the dopant particles are uniformly dispersed about the major component particles; and (d) removing the liquid medium.
Claim 7
Dependent Claim
35 words
The method of claim 4 wherein the major component is barium titanate having a particle size of about 1.0 micron and the first dopant is niobium pentoxide having a particle size of about 0.1 microns.
Claim 8
Dependent Claim
17 words
The method of claim 4 further comprising the step of sintering the ceramic powder of step (d).
Claim 9
Dependent Claim
19 words
The method of claim 4 further comprising the step of dispersing a second dopant about the major component particles.
Claim 10
Dependent Claim
50 words
The method of claim 5 wherein barium titanate comprises from about 98.5 to about 98.8 per cent by weight, niobium pentoxide comprises from about 1.0 to about 1.1 per cent by weight, and a second dopant comprising from about 0.2 to about 0.3 per cent by weight of the powder.
Claim 11
Dependent Claim
20 words
The method of claim 7 wherein the second dopant is cobalt oxide having a particle size of about 0.1 microns.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-02 | 1994-01-01 | 1994-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-02 | 1998-01-01 | 1998-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-02 | 2002-01-01 | 2002-07-03 | $7700.00 | Window Closed / Lapsed |