US4141943A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing plastic-bonded (LnCo) magnets
Assignee: UGIMAG RECOMA SA A CORP OF SWITZERLAND
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Filing: 1977-09-21
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Granted: 1979-02-27
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Expires: 1997-09-21
Abstract
Abstract The invention concerns a method of manufacturing plastic - bonded (LnCo) magnets (Ln = lanthanoid = elements 57 - 71 + yttrium), pulverization of the (LnCo) material being followed by alignment of the magnetic powder by a magnetic field, a compression process and curing of the added plastic.
Inventors
- 👤 Jaroslav Houska
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:06
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/047; H01F1/053; H01F1/055; H01F1/0555; H01F1/0558
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
200 words
A method of manufacturing a plastic-bonded LnCo magnet having improved stability at temperatures around 100° C., high energy product, essentially linear demagnetization curves over the second quadrant, and uniform magnetization of the poles, where Ln = elements 57 to 71 and yttrium, which comprises the steps of forming a green body by aligning a powdered magnetic LnCo alloy having a particle size of from 1 to 100 microns in a magnetic field, and then pressing said powder under a pressure of from 1,000 to 10,000 kp/cm 2 ; subjecting said green body to a heat treatment above its Curie temperature up to a maximum of 1150° C. in a protective atmosphere for from 1 to 20 hours, such that the resultant heat-treated body is completely demagnetized; impregnating said resultant heat-treated body with plastic in a vacuum of from about 1 to about 30 Torr. at a temperature of from about 20° to about 80° C.; pressing the resultant impregnated body at a pressure of from 2 to 2,000 kp/cm 2 ; curing the resultant pressed, impregnated body, and machining to final form; and magnetizing said cured body under the influence of a magnetic field to produce said plastic-bonded LnCo magnet.
Claim 2
Independent Claim
200 words
A method of manufacturing a plastic-bonded LnCo magnet having improved stability at temperatures around 100° C., high energy product, essentially linear demagnetization curves over the second quadrant, and uniform magnetization of the poles, where Ln = elements 57 to 71 and yttrium, which comprises the steps of forming a green body by aligning a powdered magnetic LnCo alloy having a particle size of from 1 to 100 microns in a magnetic field, and then pressing said powder under a pressure of from 1,000 to 10,000 kp/cm 2 ; subjecting said green body to a heat treatment above its Curie temperature up to a maximum of 1150° C. in a protective atmosphere for from 1 to 20 hours, such that the resultant heat-treated body is completely demagnetized; impregnating said resultant heat-treated body with plastic in a vacuum of from about 1 to about 30 Torr. at a temperature of from about 20° to about 80° C.; pressing the resultant impregnated body at a pressure of from 2 to 2,000 kp/cm 2 ; curing the resultant pressed, impregnated body, and machining to final form; and magnetizing said cured body under the influence of a magnetic field to produce said plastic-bonded LnCo magnet.
Claim 3
Dependent Claim
12 words
The method of claim 1, in which said particle size is 3-10μ.
Claim 4
Dependent Claim
17 words
The method of claim 1, in which the temperature employed in said heat treatment is 800-950° C.
Claim 5
Dependent Claim
28 words
The method of claim 1, in which said magnetic alloy is LnCo 5 with 35-37% by weight of Ln, of which at least 50% by weight is Sm.
Claim 6
Dependent Claim
23 words
The method of claim 1, in which said magnetic LnCo alloy is Ln(Co 1-y Cu y ) z , where 0<y≦0.3 and 6≦z≦8.5.
Claim 7
Dependent Claim
20 words
The method of claim 1, in which said magnetic alloy is Sm 0 .7 MM 0 .3 Co 5 .
Claim 8
Dependent Claim
13 words
The method of claim 1, in which said plastic is low-viscosity epoxy resin.
Claim 9
Dependent Claim
18 words
The method of claim 1, wherein said plastic-bonded LnCo magnet is a multipolar magnet with closely spaced poles.
Claim 10
Dependent Claim
19 words
The method of claim 1, wherein said protective atmosphere is selected from the group consisting of helium and argon.
Claim 11
Dependent Claim
22 words
The method of claim 1, wherein said powdered magnetic LnCo alloy is aligned in a magnetic field of at least 5 kG.
Claim 12
Dependent Claim
24 words
The method of claim 1, wherein said pressed, impregnated body is cured for from 2 to 4 hours at from 20° to 140° C.
Claim 13
Dependent Claim
20 words
The method of claim 1, wherein said cured body is magnetized in a magnetic field of at least 15 kG.
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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) | 1982-02-26 | 1982-08-28 | 1983-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-26 | 1986-08-28 | 1987-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-26 | 1990-08-28 | 1991-02-27 | $7700.00 | Window Closed / Lapsed |