Patent US3878280A successfully refreshed from Google Patents.
US3878280A
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Method for production of transparent yttrium oxide
Assignee: United States Department of the Army
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Filing: 1970-05-05
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Granted: 1975-04-15
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Expires: 1990-05-05
Abstract
Abstract A method for the preparation of transparent yttrium oxide by the vacuum hot pressing of yttrium oxide (Y2O3) powder in a graphite die at temperatures of between 1300* to 1500* C and uniaxial pressures of between 5000 to 7000 psi, for a period of 1 to 2 hours.
Inventors
- 👤 Sunil K Dutta
- 👤 George A Gazza
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:13
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/622; C04B35/64; C04B35/645; C04B35/50; C04B35/505; C04B2235/00; C04B2235/02; C04B2235/30; C04B2235/32; C04B2235/3231; C04B2235/3244; C04B2235/60; C04B2235/608; C04B2235/65; C04B2235/656; C04B2235/6562; C04B2235/6567; C04B2235/70; C04B2235/74; C04B2235/78; C04B2235/785; C04B2235/96; C04B2235/9646; C04B2235/9653
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
90 words
A METHOD FOR THE PRODUCTION OF TRANSPARENT YTTRIUM OXIDE COMPRISING THE STEPS OF: A. SELECTING A YTTRIUM OXIDE POWDER HAVING A PURITY OF 99.90 TO 99.99%, B. COLD COMPRESSING THE YTTRIUM POWDER TO FORM A COMPACT 54-65% OF THEORETICAL DENSITY, C. EVACUATING THE COMPACT AT A TEMPERATURE OF 300*-600*C, D. APPLYING A PEESSURE OF 5000-7000PSI, E. RAISING THE TEMPERATURE TO 1300*-1500*C, F. MAINTAINING THE PRESSURE AND TEMPERATURE FOR A PERIOD OF 1-2 HOURS, SLOWLY COOLING, AND RECOVERING TRANSPARENT YTTIUM OXIDE HAVING AN ULTRAFINE GRAIN SIZE OF LESS THAN 1 MICRON.
Claim 2
Independent Claim
90 words
A METHOD FOR THE PRODUCTION OF TRANSPARENT YTTRIUM OXIDE COMPRISING THE STEPS OF: A. SELECTING A YTTRIUM OXIDE POWDER HAVING A PURITY OF 99.90 TO 99.99%, B. COLD COMPRESSING THE YTTRIUM POWDER TO FORM A COMPACT 54-65% OF THEORETICAL DENSITY, C. EVACUATING THE COMPACT AT A TEMPERATURE OF 300*-600*C, D. APPLYING A PEESSURE OF 5000-7000PSI, E. RAISING THE TEMPERATURE TO 1300*-1500*C, F. MAINTAINING THE PRESSURE AND TEMPERATURE FOR A PERIOD OF 1-2 HOURS, SLOWLY COOLING, AND RECOVERING TRANSPARENT YTTIUM OXIDE HAVING AN ULTRAFINE GRAIN SIZE OF LESS THAN 1 MICRON.
Claim 3
Dependent Claim
22 words
A proceSs in accordance with claim 1 wherein the temperature is raised to 300*-600* C at the rate 5*-6* C per minute.
Claim 4
Dependent Claim
19 words
A process in accordance with claim 1 wherein the yttrium oxide powder is compressed to 45% of theoretical density.
Claim 5
Dependent Claim
18 words
A process in accordance with claim 1 wherein a pressure of 5000 psi is applied after the evacuation.
Claim 6
Dependent Claim
24 words
A process in accordance with claim 4 wherein a temperature of 1400* C is applied after the application of a pressure of 5000 psi.
Claim 7
Dependent Claim
19 words
A process in accordance with claim 1 wherein the yttrium oxide powder is compressed to 65% of theoretical density.
References Cited (Backward Citations)
US3545987A
Cited
US3525597A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-14 | 1978-10-14 | 1979-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-14 | 1982-10-14 | 1983-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-14 | 1986-10-14 | 1987-04-15 | $7700.00 | Window Closed / Lapsed |