US3755008A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for enhancing magnetic properties of metal powder by heat treating with salt
Assignee: VISTATECH Corp A CORP OF
•
Filing: 1971-03-24
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Granted: 1973-08-28
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Expires: 1991-03-24
Abstract
Abstract A process for enhancing the magnetic properties of small particulate ferromagnetic powders, e.g. particles below the critical diameter for which an untreated particle''s domainboundary energy equals its magnetostatic energy, the process comprising heat treating said particles. In the more favorable embodiments of the invention, the particles are heated in intimate association with a particulate refractory material which serves as a shield for effectively preventing excessive sintering of the metal particles.
Inventors
- 👤 J Ehrreich
- 👤 A Reti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:16
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/06; H01F1/065; B; B22; B22F; B22F1/00; B22F1/14; B22F1/142
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
14 words
A process as defined in claim 1 wherein said salt dust is water-soluble salt.
Claim 2
Dependent Claim
26 words
A process as defined in claim 1 wherein said heating is carried out for less than one hour at a temperature of about 450*C or below.
Claim 3
Dependent Claim
22 words
A process as defined in claim 1 wherein said heat treating is carried out at a temperature of about 350*C or below.
Claim 4
Dependent Claim
20 words
A process as defined in claim 1 wherein said heating is carried out until the coercive force exceeds 500 oersteds.
Claim 5
Dependent Claim
20 words
A process as defined in claim 1 wherein said heating is carried out until the coercive force exceeds 500 oersteds.
Claim 6
Dependent Claim
16 words
A fine magnetic powder of cobalt and formed according to the process defined by claim 1.
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Cited
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Cited
US3672867A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |