Patent US3575689A successfully refreshed from Google Patents.
US3575689A
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Method for making ferromagnetic chromium dioxide
Assignee: Panasonic Holdings Corp
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Filing: 1968-07-31
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Granted: 1971-04-20
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Expires: 1988-07-31
Abstract
Abstract FERROMAGNETIC SHROMIUM DIOXIDE IS PREPARED BY MIXING CHROMIUM TRIOXIDE AND NH4+IONS (I.E. AQUEOUS SOLUTION OF AN AMMONIUM COMPOUND OR SUCH COMPOUND PER SE), HEATING THE MIXTURE AT 280-480*C. IN AN AUTOCLAVE, FURNACE-COOLING THE MIXTURE, WASHING AND DRYING. THE WEIGHT RATIO NH4+:CR03 IS FROM 0.01:1.0 TO 0.08:1.0 ADVANTAGEOUSLY 0.01 TO 20.0 ATOMIC PRECENT OF TELLURIUM IS INCORPORATED INTO THE MIXTURE TO BE HEATED.THE OBTAINED FERROMAGNETIC CHROMIUM DIOXIDE HAS HIGH COERCIVE FORCE AND HIGH SATURATION MAGNETIZATION SO THAT IT IS USEFUL E.G. IN MAGNETIC RECORDING TAPE, ETC.
Inventors
- 👤 Toshihiro Mihara
- 👤 Yukio Terada
- 👤 Eiichi Hirota
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:31
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70636; C; C01; C01G; C01G37/00; C01G37/02; C01P; C01P2004/00; C01P2004/60; C01P2004/61; C01P2004/62; C01P2006/00; C01P2006/42
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-19 | 1974-10-19 | 1975-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-19 | 1978-10-19 | 1979-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-19 | 1982-10-19 | 1983-04-20 | $7700.00 | Window Closed / Lapsed |