Patent US3901554A successfully refreshed from Google Patents.
US3862829A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of processing ferroelectric devitrifiable glass ceramics
Assignee: United States Department of the Army
•
Filing: 1973-08-14
•
Granted: 1975-01-28
•
Expires: 1993-08-14
Abstract
Abstract The electrical properties of ferroelectric devitrifiable glass ceramics are improved by subjecting the ceramics to inert gas pressures of about 5,000 pounds per square inch to about 50,000 pounds per square inch at temperatures from about 700* C. to about 1,100* C. for about 15 minutes to about 2 hours.
Inventors
- 👤 Ronald J Brandmayr
- 👤 Sam Divita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:40
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0072
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
104 words
Method according to claim 1 wherein the ferroelectric devitrifiable glass ceramic is barium strontium niobate devitrifiable glass ceramic, the temperature is about 775*C., and the inert gas pressure is about 10,000 to about 30,000 pounds per square inch of helium; the devitrified body so obtained being characterized by a dielectric constant of 380, a dielectric strength of up to 3,000 volts per mil, a dissipation factor below 0.25 percent, and a more stable coefficient of dielectric constant under DC stress that is improved from a 20 percent change at 500 volts per mil to only a 14 percent cHange at 500 volts per mil.
Claim 2
Dependent Claim
41 words
Method according to claim 1 wherein the ferroelectric devitrifiable glass ceramic is barium strontium titanate devitrifiable glass ceramic, the temperature is about 900* C., and the inert gas pressure is about 10,000 to about 30,000 pounds per square inch of argon.
Claim 3
Dependent Claim
41 words
Method according to claim 1 wherein the ferroelectric devitrifiable glass ceramic is lead zirconate-lead titanate devitrifiable glass ceramic, the temperature is about 750* C., and the inert gas pressure is about 10,000 to about 30,000 pounds per square inch of argon.
Claim 4
Dependent Claim
33 words
Method according to claim 1 in which the ferroelectric devitrifiable glass ceramic is encapsulated in a stainless steel container back filled with oxygen prior to subjecting the ceramic to the inert gas pressures.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-27 | 1978-07-29 | 1979-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-27 | 1982-07-29 | 1983-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-27 | 1986-07-29 | 1987-01-28 | $7700.00 | Window Closed / Lapsed |