Patent US3040737A successfully refreshed from Google Patents.
Patent US3081264A successfully refreshed from Google Patents.
US3081264A
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Method of preparing a magnetic recorder powder
Assignee: MATAKE KUROKAWA
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Filing: 1959-03-30
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Granted: 1963-03-12
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Expires: 1979-03-30
Abstract
No abstract record available.
Inventors
- 👤 Nobuoka Soichiro
- 👤 Ando Tokuo
- 👤 Hayama Fumitada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:05
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70652; G11B5/70668; G11B5/70673
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
83 words
THE METHOD OF PREPARING A MAGNETIC RECORDING POWDER WHICH COMPRISES CO-PRECIPITATING COBALT AND IRON HYDROXIDES FROM AN ALKALINE MEDIUM THE MOL RATIO OF COBALT TO IRON, EXPRESSED AS COO TO FE2O3 BEING AT LEAST 0.2% BUT NO MORE THAN 1 TO 1, HEATING THE RESULTING PRECIPITATE, WITH THE MOTHER LIQUOR UNDER THE PRESSURE AT A TEMPERATURE FROM 130 TO 170* C. TO PRODUCE A CRYSTALLINE PRECIPITATE, THEN REDUCING THE RESULTING CRYSTALS IN A REDUCING ATMOSPHERE AT A TEMPERATURE FROM 350 TO 400* C.
Claim 2
Independent Claim
83 words
THE METHOD OF PREPARING A MAGNETIC RECORDING POWDER WHICH COMPRISES CO-PRECIPITATING COBALT AND IRON HYDROXIDES FROM AN ALKALINE MEDIUM THE MOL RATIO OF COBALT TO IRON, EXPRESSED AS COO TO FE2O3 BEING AT LEAST 0.2% BUT NO MORE THAN 1 TO 1, HEATING THE RESULTING PRECIPITATE, WITH THE MOTHER LIQUOR UNDER THE PRESSURE AT A TEMPERATURE FROM 130 TO 170* C. TO PRODUCE A CRYSTALLINE PRECIPITATE, THEN REDUCING THE RESULTING CRYSTALS IN A REDUCING ATMOSPHERE AT A TEMPERATURE FROM 350 TO 400* C.
References Cited (Backward Citations)
US2734033A
Cited
US1997193A
Cited
US2463413A
Cited
US2694656A
Cited
GB717269A
Cited
GB721630A
Cited
GB739069A
Cited
GB752156A
Cited
US2770523A
Cited
FR1154191A
Cited
US2929787A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1966-03-11 | 1966-09-10 | 1967-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1970-03-11 | 1970-09-10 | 1971-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1974-03-11 | 1974-09-10 | 1975-03-12 | $7700.00 | Window Closed / Lapsed |