US3897355A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making permanent ferrite magnets
Assignee: General Electric Co
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Filing: 1973-04-26
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Granted: 1975-07-29
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Expires: 1993-04-26
Abstract
Abstract A method of making sintered magnetoplumbite ferrite compositions having the formula MFe12O19 wherein M is selected from the group consisting of strontium and barium is provided. The steps comprise forming an aqueous slurry of the ferrite and a liquid phase sintering additive, orienting the ferrite to align the crystals and wet pressing the mixture to form a green compact, sintering the green compact at a temperature of about 1,100*1,300* C. for a sufficient amount of time and magnetizing the sintered ferrite compositions.
Inventors
- 👤 Ronald H Arendt
- 👤 William J Dondalski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:19
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/26; C04B35/2683
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
119 words
IN A METHOD OF MAKING A PERMANENT MAGNET FROM A MAGNETOPLUMBITE FERRITE POWDER HAVING THE FORMULA MFE12 019, WHEREIN M IS SELECTED FROM THE GROUP CONSISTING OF STRONITUM AND BARIUM, IMCLUDING THE STEPS OF ORIENTING THE FERITE POWDER TO ALIGN THE CRYSTALS AND WET PRESSING THE POWDER TO FORM A GREEN COMPACT, SINTERING THE GREEN COMPACT AT A TEMPERATURE OF ABOUT 1100*-1300*C. FOR A SUFFICIENT TIME TO FORM A BODY HAVING A DENSITY OF AT LEAST 90% OF THE THEORETICAL DENSITY AND MAGNETIZING THE SINTERED FERRITE COMPOSITION, THE IMPROVEMENT COMPRISING HOMOGENEOUSLY DISPERSING IN THE FERRITE POWDER 0.5-6.0 PERCENT BY WEIGHT OF A LIQUID PHASE SINTERING ADDITIVE SELECTED FROM THE GROUP CONSISTING OF THE FOLLOWING SYSTEMS: BAO-A12O3-SIO2 BAO-A12/3-B2O3-SIO2 SRO-A12O3-SIO2 SRO-A12O3-B2O3-SIO2
Claim 2
Dependent Claim
119 words
IN A METHOD OF MAKING A PERMANENT MAGNET FROM A MAGNETOPLUMBITE FERRITE POWDER HAVING THE FORMULA MFE12 019, WHEREIN M IS SELECTED FROM THE GROUP CONSISTING OF STRONITUM AND BARIUM, IMCLUDING THE STEPS OF ORIENTING THE FERITE POWDER TO ALIGN THE CRYSTALS AND WET PRESSING THE POWDER TO FORM A GREEN COMPACT, SINTERING THE GREEN COMPACT AT A TEMPERATURE OF ABOUT 1100*-1300*C. FOR A SUFFICIENT TIME TO FORM A BODY HAVING A DENSITY OF AT LEAST 90% OF THE THEORETICAL DENSITY AND MAGNETIZING THE SINTERED FERRITE COMPOSITION, THE IMPROVEMENT COMPRISING HOMOGENEOUSLY DISPERSING IN THE FERRITE POWDER 0.5-6.0 PERCENT BY WEIGHT OF A LIQUID PHASE SINTERING ADDITIVE SELECTED FROM THE GROUP CONSISTING OF THE FOLLOWING SYSTEMS: BAO-A12O3-SIO2 BAO-A12/3-B2O3-SIO2 SRO-A12O3-SIO2 SRO-A12O3-B2O3-SIO2
Claim 3
Dependent Claim
10 words
The method of claim 1, wherein said ferrite is BaFe12O19.
Claim 4
Dependent Claim
10 words
The method of claim 1, wherein said ferrite is SrFe12O19.
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) | 1978-07-28 | 1979-01-27 | 1979-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-28 | 1983-01-27 | 1983-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-28 | 1987-01-27 | 1987-07-29 | $7700.00 | Window Closed / Lapsed |