US4318995A
Expired / Lapsed
US
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Method of preparing lightly doped ceramic materials
Assignee: AT&T Inc
•
Filing: 1980-04-25
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Granted: 1982-03-09
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Expires: 2000-04-25
Abstract
Abstract A method of preparing lightly doped ceramic materials which forms a slurry of the ceramic material with additives in solution, precipitates the additives and spray dries the slurry with the additive precipitates is described.
Inventors
- 👤 Warren W. Rhodes
- 👤 Man F. Yan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:10
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/10; H01C7/105; H01C7/108; H01C7/112; C; C04; C04B; C04B35/00; C04B35/01; C04B35/46
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
107 words
A method of preparing ceramic material selected from the group consisting of TiO 2 , ZnO, Al 2 O 3 and BaTiO 3 having at least one additive selected from the group consisting of the elements of Group IIA of the Periodic Table and at least one additive selected from the group consisting of the elements of Group VB of the Periodic Table comprising the steps of forming a slurry of said ceramic material, said slurry further comprising a dispersant said slurry having said at least one Group IIA additive and said Group VB additive in solution; precipitating said additives; spray drying said slurry and precipitated additives.
Claim 2
Independent Claim
107 words
A method of preparing ceramic material selected from the group consisting of TiO 2 , ZnO, Al 2 O 3 and BaTiO 3 having at least one additive selected from the group consisting of the elements of Group IIA of the Periodic Table and at least one additive selected from the group consisting of the elements of Group VB of the Periodic Table comprising the steps of forming a slurry of said ceramic material, said slurry further comprising a dispersant said slurry having said at least one Group IIA additive and said Group VB additive in solution; precipitating said additives; spray drying said slurry and precipitated additives.
Claim 3
Dependent Claim
27 words
A method as recited in claim 1 in which said Group IIA additive and Group VB additives form 10 weight percent or less of said ceramic material.
Claim 4
Dependent Claim
16 words
A method as recited in claim 2 in which said ceramic material is TiO 2 .
Claim 5
Dependent Claim
15 words
A method as recited in claim 3 in which said Group IIA additive is barium.
Claim 6
Dependent Claim
22 words
A method as recited in claim 4 in which said barium additive is present in an amount less than 1.0 mole percent.
Claim 7
Dependent Claim
28 words
A method as recited in claim 5 in which said barium additive is present in an amount greater than 0.15 mole percent and less than 0.3 mole percent.
Claim 8
Dependent Claim
23 words
A method as recited in claim 6 in which said Group VB element is present in an amount less than 5 mole percent.
Claim 9
Dependent Claim
37 words
A method as recited in claim 4 or 7 in which said additive selected from Group VB is niobium, said niobium being present in an amount greater than 0.3 mole percent and less than 0.8 mole percent.
Claim 10
Dependent Claim
13 words
A method as recited in claim 8 comprising the further step of sintering.
Claim 11
Dependent Claim
22 words
A method as recited in claim 9 in which said sintering is at a temperature between 1350 degrees and 1450 degrees C.
Claim 12
Dependent Claim
25 words
A method as recited in claim 10 in which said sintering is in an atmosphere with an oxygen partial pressure greater than 10 -5 atmosphere.
Claim 13
Dependent Claim
17 words
A method as recited in claim 8 in which said additives are barium nitrate and niobium oxalate.
Claim 14
Dependent Claim
22 words
A method as recited in claim 12 in which said precipitating step comprises adding ammonium sulfate and ammonium hydroxide to said slurry.
References Cited (Backward Citations)
GB755860A
Cited
US3528919A
Cited
US3549315A
Cited
GB1282307A
Cited
US3663284A
Cited
US3938064A
Cited
US3983077A
Cited
US4173485A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-03-08 | 1985-09-07 | 1986-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-03-08 | 1989-09-07 | 1990-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-03-08 | 1993-09-07 | 1994-03-09 | $7700.00 | Window Closed / Lapsed |