US4131444A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for increasing the strength and density of lead titanate ceramic bodies
Assignee: United States Department of the Navy
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Filing: 1977-08-25
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Granted: 1978-12-26
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Expires: 1997-08-25
Abstract
Abstract Strengthened and densified ceramic bodies are produced by hot pressing lead titanate powder into a lead titanate ceramic at a pressure from 1000 to 5000 psi and at a temperature from 700 to 1100 DEG C if the atmosphere is reducing or from 700 to 1200 DEG C if the atmosphere is oxidizing and by annealing the lead titanate ceramic at a temperature from 600 to 1100 DEG C in an oxidizing atmosphere for at least four hours.
Inventors
- 👤 Basil E. Walker
- 👤 Robert C. Pohanka
- 👤 Paul L. Smith
- 👤 Roy W. Rice
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:26
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/64; C04B35/645; C04B35/01; C04B35/46; C04B35/462; C04B35/472
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
103 words
A method for producing a lead titanate ceramic from a lead titanate composition susceptible to Curie-point degradation which comprises hot-pressing a lead titanate composition comprising at least 98 weight percent of lead titanate with no other constituent in excess of one weight percent to form a lead titanate ceramic at a pressure from 1000 to 9000 psi and at a temperature from 700° C. to 1100° C. if said lead titanate is in a reducing atmosphere or at a temperature from 700° to 1200° C. if said lead titanate is in an oxidizing atmosphere; and cooling said lead titanate ceramic to room temperature.
Claim 2
Independent Claim
103 words
A method for producing a lead titanate ceramic from a lead titanate composition susceptible to Curie-point degradation which comprises hot-pressing a lead titanate composition comprising at least 98 weight percent of lead titanate with no other constituent in excess of one weight percent to form a lead titanate ceramic at a pressure from 1000 to 9000 psi and at a temperature from 700° C. to 1100° C. if said lead titanate is in a reducing atmosphere or at a temperature from 700° to 1200° C. if said lead titanate is in an oxidizing atmosphere; and cooling said lead titanate ceramic to room temperature.
Claim 3
Dependent Claim
38 words
The method of claim 1 which further comprises annealing said lead titanate ceramic at a temperature from 600° C. to 1100° C. in an oxidizing atmosphere for at least four hours and cooling said ceramic to room temperature.
Claim 4
Dependent Claim
28 words
The method of claim 1 wherein lead titanate is hot-pressed at a temperature from 900° C. to 1000° C. and at a pressure from 2000 to 3000 psi.
Claim 5
Dependent Claim
10 words
The method of claim 3 wherein said atmosphere is reducing.
Claim 6
Dependent Claim
27 words
The method of claim 4 which further comprises annealing said lead titanate ceramic at a temperature from 700° C. to 900° C. for at least 6 hours.
Claim 7
Dependent Claim
14 words
The method of claim 1 wherein said lead titanate consists of essentially lead titanate.
Claim 8
Dependent Claim
15 words
The method of claim 3 wherein said lead titanate composition consists essentially of lead titanate.
Claim 9
Dependent Claim
15 words
The method of claim 4 wherein said lead titanate composition consists essentially of lead titanate.
Claim 10
Dependent Claim
15 words
The method of claim 5 wherein said lead titanate composition consists essentially of lead titanate.
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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) | 1981-12-25 | 1982-06-26 | 1982-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-25 | 1986-06-26 | 1986-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-25 | 1990-06-26 | 1990-12-26 | $7700.00 | Window Closed / Lapsed |