Patent US4474431A successfully refreshed from Google Patents.
Patent US2736708A successfully refreshed from Google Patents.
US2736708A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic compositions
Assignee: Henry L Crowley & Co Inc
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Filing: 1951-06-08
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Granted: 1956-02-28
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Expires: 1971-06-08
Abstract
No abstract record available.
Inventors
- 👤 Henry L Crowley
- 👤 Arthur M Hossenlopp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 11:59
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/26; C04B35/265
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
221 words
IN A METHOD OF PREPARING A MAGNETIC COMPOSITION IN WHICH FERRIC OXIDE, NICKEL OXIDE AND ZINC OXIDE ARE INTIMATELY MIXED TO PRODUCE AN INITIAL OXIDE MIXTURE CONTAINING FROM 50 TO 90% BY WEIGHT OF FERRIC OXIDE AND IN WHICH THE WEIGHT RATIO OF ZINC OXIDE AND NICKEL OXIDE IS BETWEEN ABOUT 2 TO 1 AND ABOUT 1 TO 1, THE OXIDE MIXTURE IS SUBJECTED TO A TWO-STAGE HEAT-TREATMENT FOLLOWED BY GRADUAL COOLING OF THE PRODUCT OF THE SECOND STAGE OF HEAT-TREATMENT AND IN THE COURSE OF THE FIRST HEAT-TREATMENT A PORTION OF THE FERRIC OXIDE IS REDUCED TO FERROUS OXIDE AND AT THE CONCLUSION OF THE FIRST HEAT-TREATMENT THE HEAT-TREATED PRODUCT CONTAINS FERROUS OXIDE AND IS NONMAGNETIC, THE FIRST HEAT-TREATMENT BEING CARRIED OUT AT A TEMPERATURE BETWEEN 800* AND 1200* C. UNDER NON-OXIDIZING CONDITIONS, AND THE SECOND HEAT-TREATMENT BEING CARRIED OUT AT A SOMEWHAT HIGHER TEMPERATURE BETWEEN 1000* AND 1450* C., UNDER NON-OXIDIZING CONDITIONS, THE NON-OXIDIZING CONDITIONS OF AT LEAST ONE OF SAID HEATTREATMENTS BEING REDUCING TO INSURE THE PRESENCE OF FERROUS OXIDE IN THE SECOND HEAT-TREATMENT; THE IMPROVEMENT WHICH COMPRISES INTIMATELY MIXING WITH THE PRODUCT OF THE FIRST HEAT-TREATMENT AN OXIDE OF COBALT IN THE AMOUNT, EXPRESSED AS CO2O3, OF FROM 0.1 TO 50 PARTS BY WEIGHT OF SAID OXIDE OF COBALT PER 100 PARTS BY WEIGHT OF SAID PRODUCT.
Claim 2
Dependent Claim
221 words
IN A METHOD OF PREPARING A MAGNETIC COMPOSITION IN WHICH FERRIC OXIDE, NICKEL OXIDE AND ZINC OXIDE ARE INTIMATELY MIXED TO PRODUCE AN INITIAL OXIDE MIXTURE CONTAINING FROM 50 TO 90% BY WEIGHT OF FERRIC OXIDE AND IN WHICH THE WEIGHT RATIO OF ZINC OXIDE AND NICKEL OXIDE IS BETWEEN ABOUT 2 TO 1 AND ABOUT 1 TO 1, THE OXIDE MIXTURE IS SUBJECTED TO A TWO-STAGE HEAT-TREATMENT FOLLOWED BY GRADUAL COOLING OF THE PRODUCT OF THE SECOND STAGE OF HEAT-TREATMENT AND IN THE COURSE OF THE FIRST HEAT-TREATMENT A PORTION OF THE FERRIC OXIDE IS REDUCED TO FERROUS OXIDE AND AT THE CONCLUSION OF THE FIRST HEAT-TREATMENT THE HEAT-TREATED PRODUCT CONTAINS FERROUS OXIDE AND IS NONMAGNETIC, THE FIRST HEAT-TREATMENT BEING CARRIED OUT AT A TEMPERATURE BETWEEN 800* AND 1200* C. UNDER NON-OXIDIZING CONDITIONS, AND THE SECOND HEAT-TREATMENT BEING CARRIED OUT AT A SOMEWHAT HIGHER TEMPERATURE BETWEEN 1000* AND 1450* C., UNDER NON-OXIDIZING CONDITIONS, THE NON-OXIDIZING CONDITIONS OF AT LEAST ONE OF SAID HEATTREATMENTS BEING REDUCING TO INSURE THE PRESENCE OF FERROUS OXIDE IN THE SECOND HEAT-TREATMENT; THE IMPROVEMENT WHICH COMPRISES INTIMATELY MIXING WITH THE PRODUCT OF THE FIRST HEAT-TREATMENT AN OXIDE OF COBALT IN THE AMOUNT, EXPRESSED AS CO2O3, OF FROM 0.1 TO 50 PARTS BY WEIGHT OF SAID OXIDE OF COBALT PER 100 PARTS BY WEIGHT OF SAID PRODUCT.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-02-27 | 1959-08-29 | 1960-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-02-27 | 1963-08-29 | 1964-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-02-27 | 1967-08-29 | 1968-02-28 | $7700.00 | Window Closed / Lapsed |