US3288563A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing a powder for magnetic recording consisting of magnetic iron oxide
Assignee: US Philips Corp
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Filing: 1963-05-03
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Granted: 1966-11-29
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Expires: 1983-05-03
Abstract
No abstract record available.
Inventors
- 👤 Klomp Cornelis Johannes
- 👤 Gerard Williem Van Oosterhout
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 08:00
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70652; G11B5/70663; C; C01; C01G; C01G49/00; C01G49/02; C01G49/06; G11B5/70647
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
92 words
A METHOD OF PRODUCING A POWDER FOR MAGNETIC RECORDING HAVING AN INCREASED SIGNAL-TO-NOISE RATIO COMPRISING THE STEPS OF OXIDIZING A FERROUS COMPOUND RELATIVELY INSOLUBLE IN WATER IN AN ALKALINE LIQUID CONSISTING ESSENTIALLY OF WATER AND HAVING AN (OH)- ION CONCENTRATION OF MORE THAN 0.2 NORMAL BY PASSING AN OXIDIZING GAS THROUGH THE ALKALINE LIQUID CONTAINING THE FERROUS COMPOUND TO FORM CRYSTALLINE FERRIC OXIDE HYDRATE HAVING A CHEMICAL COMPOSITION CORRESPONDING TO THE FORMULA FE2O3.NH2O, IN WHICH 1$N$2, AND CONVERTING SAID FERRIC OXIDE HYDRATE BY REDUCTION AND SUBSEQUENT OXIDATION INTO MAGNETIC IRON OXIDE, Y-FE2O3.
Claim 2
Independent Claim
92 words
A METHOD OF PRODUCING A POWDER FOR MAGNETIC RECORDING HAVING AN INCREASED SIGNAL-TO-NOISE RATIO COMPRISING THE STEPS OF OXIDIZING A FERROUS COMPOUND RELATIVELY INSOLUBLE IN WATER IN AN ALKALINE LIQUID CONSISTING ESSENTIALLY OF WATER AND HAVING AN (OH)- ION CONCENTRATION OF MORE THAN 0.2 NORMAL BY PASSING AN OXIDIZING GAS THROUGH THE ALKALINE LIQUID CONTAINING THE FERROUS COMPOUND TO FORM CRYSTALLINE FERRIC OXIDE HYDRATE HAVING A CHEMICAL COMPOSITION CORRESPONDING TO THE FORMULA FE2O3.NH2O, IN WHICH 1$N$2, AND CONVERTING SAID FERRIC OXIDE HYDRATE BY REDUCTION AND SUBSEQUENT OXIDATION INTO MAGNETIC IRON OXIDE, Y-FE2O3.
References Cited (Backward Citations)
US2560970A
Cited
US3015628A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-11-28 | 1970-05-30 | 1970-11-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-11-28 | 1974-05-30 | 1974-11-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-11-28 | 1978-05-30 | 1978-11-29 | $7700.00 | Window Closed / Lapsed |