US3402993A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Growth of ferrous-free cobalt ferrite single crystals
Assignee: Massachusetts Institute of Technology
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Filing: 1963-11-29
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Granted: 1968-09-24
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Expires: 1983-11-29
Abstract
No abstract record available.
Inventors
- 👤 Ferretti August
- 👤 Kunnmann Walter
- 👤 Wold Aaron
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:56
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/26; C04B35/2666; C30; C30B; C30B11/00; C30B29/00; C30B29/10; C30B29/16; C30B29/22; C30B29/26
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
129 words
A METHOD OF MAKING FERROUS-FREE COBALT FERRITE SINGLE CRYSTALS COMPRISING THE STEPS OF: DECOMPOSING COBALT PYRIDINATE; FUSING AN EQUIMOLAR MIXTURE OF SODIUM CARBONATE AND FERRIC OXIDE IN AN APPROPRIATE FURNACE; COMBINING ONE PART BY WEIGHT OF SAID DECOMPOSED COBALT PYRIDINATE WITH NINETEEN PARTS BY WEIGHT OF SAID FUSED SODIUM CARBONATE AND FERRIC OXIDE IN A PLATINUM CRUCIBLE; HEATING SAID COMBINATION IN AN OXYGEN ATMOSPHERE MAINTAINED AT 165 P.S.I.G. TO A TEMPERATURE OF ABOUT 1600*C.; HOLDING SAID TEMPERATURE FOR A PERIOD OF ABOUT TWO HOURS PERMITTING ALL EXTRANEOUS NUCLEI TO DISSOLVE; COOLING SAID HEATED COMBINATION AT A RATE OF ABOUT 6*C. PER HOUR FOR SIXTEEN HOURS, THAN 10*C. PER HOUR FOR THE NEXT TEN HOURS, AND FINALLY 40*C. PER HOUR UNTIL ROOM TEMPERATURE IS ACHIEVED; AND REMOVING SAID OXYGEN ATMOSPHERE.
Claim 2
Independent Claim
129 words
A METHOD OF MAKING FERROUS-FREE COBALT FERRITE SINGLE CRYSTALS COMPRISING THE STEPS OF: DECOMPOSING COBALT PYRIDINATE; FUSING AN EQUIMOLAR MIXTURE OF SODIUM CARBONATE AND FERRIC OXIDE IN AN APPROPRIATE FURNACE; COMBINING ONE PART BY WEIGHT OF SAID DECOMPOSED COBALT PYRIDINATE WITH NINETEEN PARTS BY WEIGHT OF SAID FUSED SODIUM CARBONATE AND FERRIC OXIDE IN A PLATINUM CRUCIBLE; HEATING SAID COMBINATION IN AN OXYGEN ATMOSPHERE MAINTAINED AT 165 P.S.I.G. TO A TEMPERATURE OF ABOUT 1600*C.; HOLDING SAID TEMPERATURE FOR A PERIOD OF ABOUT TWO HOURS PERMITTING ALL EXTRANEOUS NUCLEI TO DISSOLVE; COOLING SAID HEATED COMBINATION AT A RATE OF ABOUT 6*C. PER HOUR FOR SIXTEEN HOURS, THAN 10*C. PER HOUR FOR THE NEXT TEN HOURS, AND FINALLY 40*C. PER HOUR UNTIL ROOM TEMPERATURE IS ACHIEVED; AND REMOVING SAID OXYGEN ATMOSPHERE.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-09-24 | 1972-03-25 | 1972-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-09-24 | 1976-03-25 | 1976-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-09-24 | 1980-03-25 | 1980-09-24 | $7700.00 | Window Closed / Lapsed |