US3778373A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Iron containing ferromagnetic chromium oxide
Assignee: Bell and Howell Co
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Filing: 1971-11-08
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Granted: 1973-12-11
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Expires: 1991-11-08
Abstract
Abstract FERROMAGNETIC CHROMIUM OXIDE HAVING AN INTRINSIC COERCIVE FORCE ABOVE 600 OERSTEDS IS PREPARED BY HEATING AN INTIMATE MIXTURE OF CHROMIUM (III) AND IRON (III) COMBINED WITH OXYGEN WITH AN OXIDIZING AGENT. IN PARTICULAR EMBODIMENTS, THE MIXTURE IS OBTAINED BY CO-PRECIPITATION OF THE HYDROXIDES FROM A SOLUTION OF CHROMIUM (III) AND IRON (III) SALTS.
Inventors
- 👤 H Robbins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:08
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70636
Claims Analysis
Total Claims: 0
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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) | 1976-12-10 | 1977-06-11 | 1977-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-10 | 1981-06-11 | 1981-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-10 | 1985-06-11 | 1985-12-11 | $7700.00 | Window Closed / Lapsed |