US3609084A
Expired / Lapsed
US
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Lithium ferrite composition for magnetic memory elements and manufacturing process thereof
Assignee: FERRITES ELECTRONIQUES COFELEC
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Filing: 1968-05-15
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Granted: 1971-09-28
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Expires: 1988-05-15
Abstract
Abstract A composition comprising by mole percent: Fe2O3: 50 to 80 percent; Li20: 8 to 18 percent, at least one oxide chosen from the following group: MgO, A12O3, CaO, Cr2O3, NiO, CuO, ZnO, CdO: 0 to 10 percent; Mn0: 0 to 40 percent; SiO2 up to 5 percent. The temperature of 1,200* C. is never exceeded in the course of the preparation. The Curie point is above 500* C.
Inventors
- 👤 Norbert Loye
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:32
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/26; C04B35/2691; C04B35/2608; C04B35/2616; C04B35/2625
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
41 words
A sintered lithium ferrite composition as claimed in claim 1, comprising by mole percent: Li2O: 14 percent; Fe2O3: 80 percent; MnO: 4.5 percent; SiO2: 1.5 percent, the sintering temperature being of about 1,175* C., and the sintering atmosphere being pure oxygen.
Claim 2
Dependent Claim
49 words
A sintered lithium ferrite composition as claimed in claim 1, comprising by mole percent: Fe2O3: 76.5 percent; Li2O: 13.5 percent; MnO: 7.3 percent; ZnO: 0.5 percent; SiO2: 2.2 percent; the sintering temperature being of about 1,100* C. and the sintering atmosphere containing 20 percent oxygen and 80 percent nitrogen.
Claim 3
Dependent Claim
109 words
A process for manufacturing sintered ferrite compositions for magnetic cores having rectangular hysteresis cycle comprising the steps of mixing by mole percent: Fe2O3: 50 to 80 percent; Li2O: 8 to to 18 percent; at least one oxide chosen from the group MgO, Al2O3, CaO, Cr2O3, NiO, CuO, ZnO, CdO: 0 to 10 percent; SiO2 one of the specific amounts 1.5 percent and 2.2 percent; MnO: 0 to 40 percent, grinding said mixture in ethyl alcohol, presintering it for 2 hours at a temperature lower than 1,100* C., in atmosphere containing oxygen; grinding in distilled water, pressing and sintering in atmosphere containing oxygen at a temperature not exceeding 1,200* C.
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) | 1974-09-27 | 1975-03-29 | 1975-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-27 | 1979-03-29 | 1979-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-27 | 1983-03-29 | 1983-09-28 | $7700.00 | Window Closed / Lapsed |