Patent US2501128A successfully refreshed from Google Patents.
US2501128A
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Method of preparing ferromagnetic powder
Assignee: Magnaflux Corp
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Filing: 1947-04-18
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Granted: 1950-03-21
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Expires: 1967-04-18
Abstract
No abstract record available.
Inventors
- 👤 Robert J Kerr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:39
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/20; H01F1/22; H01F1/24
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
108 words
THE METHOD OF PREPARING A FERROMAGNETIC POWDER HAVING A PERMANENTLY ADHERENT FILM THEREOVER OF BLACK FEO, WHICH COMPRISES MIXING A FERROMAGNETIC POWDER WIH FROM 1/2 TO 3% BY WEIGHT OF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF DRYING AND SEMI-DRYING OILS AND HEATING THE RESULTING MIXTURE IN THE PRESENCE OF AIR TO THAT TEMPERATURE WITHIN THE RANGE OF 475* TO 675*F. AT WHICH FOR THE PARTICULAR MATERIAL SELECTED REACTION OCCURS TO PRODUCE A FILM OF BLACK FEO ON THE SURFACES OF SAID POWDER, THE HEATING BEING CARRIED OUT AT SUCH RATE AS TO INSURE THAT THE OIL SELECTED IS NOT DRIVEN OFF BEFORE THE REACTION IS COMPLETE.
Claim 2
Independent Claim
108 words
THE METHOD OF PREPARING A FERROMAGNETIC POWDER HAVING A PERMANENTLY ADHERENT FILM THEREOVER OF BLACK FEO, WHICH COMPRISES MIXING A FERROMAGNETIC POWDER WIH FROM 1/2 TO 3% BY WEIGHT OF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF DRYING AND SEMI-DRYING OILS AND HEATING THE RESULTING MIXTURE IN THE PRESENCE OF AIR TO THAT TEMPERATURE WITHIN THE RANGE OF 475* TO 675*F. AT WHICH FOR THE PARTICULAR MATERIAL SELECTED REACTION OCCURS TO PRODUCE A FILM OF BLACK FEO ON THE SURFACES OF SAID POWDER, THE HEATING BEING CARRIED OUT AT SUCH RATE AS TO INSURE THAT THE OIL SELECTED IS NOT DRIVEN OFF BEFORE THE REACTION IS COMPLETE.
References Cited (Backward Citations)
US40964A
Cited
US77186A
Cited
US1274952A
Cited
US1362213A
Cited
US1383703A
Cited
US2064771A
Cited
GB463511A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-03-20 | 1953-09-19 | 1954-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-03-20 | 1957-09-19 | 1958-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-03-20 | 1961-09-19 | 1962-03-21 | $7700.00 | Window Closed / Lapsed |