US4081297A
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RE-Co-Fe-transition metal permanent magnet and method of making it
Assignee: UGIMAG RECOMA SA A CORP OF SWITZERLAND
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Filing: 1976-09-10
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Granted: 1978-03-28
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Expires: 1996-09-10
Abstract
Abstract A permanent magnet consists of a rare earth element (RE) or a mixture thereof, cobalt, iron and a transition metal (TM) selected from the group consisting of chromium, manganese, titanium, tungsten, molybdenum, and mixtures thereof; wherein for each two moles of the rare earth elements there are 14-19 moles of all other elements.
Inventors
- 👤 Hartmut Nagel
- 👤 Roger Perkins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:30
CPC Classifications
C; C22; C22C; C22C19/00; C22C19/07; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/047; H01F1/053; H01F1/055; H01F1/0555; H01F1/0557
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
200 words
A rare earth permanent magnet comprising an alloy consisting essentially of: RE.sub.2 (Co.sub.1-x-y Fe.sub.x TM.sub.y).sub.17+z wherein: Re is at least one rare earth element; Tm is at least one transition element selected from the group consisting of chromium, manganese, titanium, tungsten and molybdenum; -≦ z ≦ 1; 0.5 < (1-x-y) < 1 0.1 ≦ x ≦ 0.225 0.025 ≦ y ≦ 0.1 wherein said rare earth permanent magnet is further characterized by possessing high values of coercive field strength, an ideal demagnetization curve and a remanence of more than 9KG and wherein said rare earth permanent magnet is prepared by the process which comprises mixing together a starting alloy of the composition RE 2 (Co 1-x-y Fe x TM y ) 17+z and 8 to 14 wt.% of a samarium-rich sinter additive compound composed of 50-60 wt.% samarium and 40-50 wt.% of an alloy Co 1-x-y Fe x TM y wherein both said starting alloy and said sinter additive are each in powder form of average grain size 2.0 to 10μm; magnetically aligning the mix; compressing it to a greenling; sintering it to form a magnet; and subjecting said magnet to a heat treatment to 400° C - 600° C.
Claim 2
Dependent Claim
200 words
A rare earth permanent magnet comprising an alloy consisting essentially of: RE.sub.2 (Co.sub.1-x-y Fe.sub.x TM.sub.y).sub.17+z wherein: Re is at least one rare earth element; Tm is at least one transition element selected from the group consisting of chromium, manganese, titanium, tungsten and molybdenum; -≦ z ≦ 1; 0.5 < (1-x-y) < 1 0.1 ≦ x ≦ 0.225 0.025 ≦ y ≦ 0.1 wherein said rare earth permanent magnet is further characterized by possessing high values of coercive field strength, an ideal demagnetization curve and a remanence of more than 9KG and wherein said rare earth permanent magnet is prepared by the process which comprises mixing together a starting alloy of the composition RE 2 (Co 1-x-y Fe x TM y ) 17+z and 8 to 14 wt.% of a samarium-rich sinter additive compound composed of 50-60 wt.% samarium and 40-50 wt.% of an alloy Co 1-x-y Fe x TM y wherein both said starting alloy and said sinter additive are each in powder form of average grain size 2.0 to 10μm; magnetically aligning the mix; compressing it to a greenling; sintering it to form a magnet; and subjecting said magnet to a heat treatment to 400° C - 600° C.
Claim 3
Dependent Claim
34 words
The permanent magnet of claim 1, wherein the rare earth (RE) element is samarium, or a mixture of samarium and a light rare earth element of atomic number 57-62, misch metal or mixtures thereof.
Claim 4
Dependent Claim
23 words
The permanent magnet of claim 1, wherein the average grain size of the material used to prepare the magnet is smaller than 3.0μm.
Claim 5
Dependent Claim
12 words
The permanent magnet of claim 1, which has a predominantly single-phase structure.
Claim 6
Dependent Claim
191 words
A process for preparing a rare earth permanent magnet comprising an alloy consisting essentially of: RE.sub.2 (Co.sub.1-x-y Fe.sub.x TM.sub.y).sub.17+z wherein: Re is at least one rare earth element; Tm is at least one transition element selected from the group consisting of chromium, manganese, titanium, tungsten and molybdenum; -≦ z ≦1; 0.5 < (1-x-y) < 1 0.1 ≦ x ≦ 0.255 0.025 ≦ y ≦ 0.1 wherein said rare earth permanent magnet is further characterized by possessing high values of coercive field strength, an ideal demagnetization curve and a remanence of more than 9KG; which comprises mixing together a starting alloy of the composition RE 2 (Co 1-x-y Fe x TM y ) 17+z and 8 to 14 wt.% of a samarium-rich sinter additive compound composed of 50-60 wt.% samarium and 40-50 wt.% of an alloy Co 1-x-y Fe x TM y wherein both said starting alloy and said sinter additive are each in powder form of average grain size 2.0 to 10μm; magnetically aligning the mix; compressing it to a greenling; sintering it to form a magnet; and subjecting said magnet to a heat treatment to 400° C - 600° C.
Claim 7
Dependent Claim
191 words
A process for preparing a rare earth permanent magnet comprising an alloy consisting essentially of: RE.sub.2 (Co.sub.1-x-y Fe.sub.x TM.sub.y).sub.17+z wherein: Re is at least one rare earth element; Tm is at least one transition element selected from the group consisting of chromium, manganese, titanium, tungsten and molybdenum; -≦ z ≦1; 0.5 < (1-x-y) < 1 0.1 ≦ x ≦ 0.255 0.025 ≦ y ≦ 0.1 wherein said rare earth permanent magnet is further characterized by possessing high values of coercive field strength, an ideal demagnetization curve and a remanence of more than 9KG; which comprises mixing together a starting alloy of the composition RE 2 (Co 1-x-y Fe x TM y ) 17+z and 8 to 14 wt.% of a samarium-rich sinter additive compound composed of 50-60 wt.% samarium and 40-50 wt.% of an alloy Co 1-x-y Fe x TM y wherein both said starting alloy and said sinter additive are each in powder form of average grain size 2.0 to 10μm; magnetically aligning the mix; compressing it to a greenling; sintering it to form a magnet; and subjecting said magnet to a heat treatment to 400° C - 600° C.
Claim 8
Dependent Claim
25 words
The method of claim 5, wherein the starting alloy and the sintering additive are ground to an average grain size of from 2.0 to 5μm.
Claim 9
Dependent Claim
23 words
The method of claim 5, wherein the greenling is sintered in the temperature range of 1110° to 1180° C to form a magnet.
Claim 10
Dependent Claim
24 words
The method of claim 5, wherein the magnet, after the sintering treatment, is homogenization-annealed in the temperature range of from 1000° to 1100° C.
Claim 11
Dependent Claim
22 words
The method of claim 5, wherein the magnet, after the sintering or the homogenization treatment, is tempered at 400° to 600° C.
Claim 12
Dependent Claim
14 words
The method of claim 5, wherein the magnet is magnetized after being heat treated.
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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) | 1981-03-27 | 1981-09-26 | 1982-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-27 | 1985-09-26 | 1986-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-27 | 1989-09-26 | 1990-03-28 | $7700.00 | Window Closed / Lapsed |