US4601875A
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Process for producing magnetic materials
Assignee: Proterial Ltd
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Filing: 1983-09-15
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Granted: 1986-07-22
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Expires: 2003-09-15
Abstract
Abstract Permanent magnetic materials of the Fe-B-R type are produced by: preparing an metallic powder having a mean particle size of 0.3-80 microns and a composition of, by atomic percent, 8-30% R (rare earth elements), 2-28% B, and the balance Fe, compacting, sintering at a temperature of 900-1200 degrees C., and aging at a temperature ranging from 350 degrees C. to the temperature for sintering. Co and additional elements M (Ti, Ni, Bi, V, Nb, Ta, Cr, Mo, W, Mn, Al, Sb, Ge, Sn, Zr, Hf) may be present.
Inventors
- 👤 Hitoshi Yamamoto
- 👤 Masato Sagawa
- 👤 Setsuo Fujimura
- 👤 Yutaka Matsuura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:05
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/047; H01F1/053; H01F1/055; H01F1/057; H01F1/0571; H01F1/0575; H01F1/0577; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49075; Y10T29/49076
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
110 words
A process of producing a permanent magnet of the Fe-B-R type comprising: providing a sintered body having a composition consisting essentially of, by atomic percent, 12-24% R wherein R is at least one element selected from the group consisting of Nd, Pr, La, Ce, Tb, Dy, Ho, Er, Eu, Sm, Gd, Pm, Tm, Yb, Lu and Y and at least 50% of R consists of Nd and/or Pr, 4-24% B, and at least 52% Fe, and heat-treating the sintered body at a temperature ranging from 350 degrees C. to the sintering temperature in a non-oxidizing atmosphere for at least 5 minutes to increase the intrinsic coercivity of the sintered body.
Claim 2
Dependent Claim
110 words
A process of producing a permanent magnet of the Fe-B-R type comprising: providing a sintered body having a composition consisting essentially of, by atomic percent, 12-24% R wherein R is at least one element selected from the group consisting of Nd, Pr, La, Ce, Tb, Dy, Ho, Er, Eu, Sm, Gd, Pm, Tm, Yb, Lu and Y and at least 50% of R consists of Nd and/or Pr, 4-24% B, and at least 52% Fe, and heat-treating the sintered body at a temperature ranging from 350 degrees C. to the sintering temperature in a non-oxidizing atmosphere for at least 5 minutes to increase the intrinsic coercivity of the sintered body.
Claim 3
Dependent Claim
30 words
A process as defined in claim 1, in which Co is substituted for Fe in an amount greater than zero and not exceeding 45 atomic percent of the sintered body.
Claim 4
Dependent Claim
94 words
A process as defined in claim 1, wherein said composition comprises at least one of additional elements M of no more than the values by atomic percent as specified hereinbelow provided that, when two or more elements M are added, the total amount thereof shall be no more than the largest value among said specified values of the elements actually added: 3.5% Ti, 2.0% Ni, 3.0% Bi, 6.5% V, 8.5% Nb, 8.5% Ta, 4.5% Cr, 5.5% Mo, 5.5% W, 4.0% Mn, 5.5% Al, 0.5% Sb, 4.0% Ge, 1.0% Sn, 3.5% Zr, and 3.5% Hf.
Claim 5
Dependent Claim
30 words
A process as defined in claim 3, in which Co is substituted for Fe in an amount greater than zero and not exceeding 45 atomic percent of the sintered body.
Claim 6
Dependent Claim
80 words
A process as defined in any one of claims 1-4, wherein the step of providing said sintered body comprises: preparing a metallic powder having said composition and a mean particle size of 0.3-80 microns, compacting said metallic powder in a magnetic field, and sintering the compacted body at a temperature of 900-1200 degrees C. in a nonoxidizing or reducing atmosphere for at least 5 minutes; and wherein the resultant magnet has a maximum energy product of at least 10 MGOe.
Claim 7
Dependent Claim
96 words
A process as defined in any one of claims 1-4, wherein the step of providing said sintered body comprises: preparing a metallic powder having a mean particle size of 0.3-80 microns and a composition consisting essentially of, by atomic percent, 12-20% R, 5-18% B, and at least 62% Fe, compacting said metallic powder without applying a magnetic field, and sintering the compacted body at a temperature of 900-1200 degrees C. in a nonoxidizing or reducing atmosphere for at least 5 minutes; and wherein the resultant magnet has a maximum energy product of at least 4 MGOe.
Claim 8
Dependent Claim
21 words
A process as defined in any one of claims 1-4, wherein the heat-treating is carried out after cooling following the sintering.
Claim 9
Dependent Claim
20 words
A process as defined in any one of claims 1-4, wherein the heat-treating is carried out immediately following the sintering.
Claim 10
Dependent Claim
26 words
A process as defined in claim 7, wherein the cooling following the sintering is carried out at a cooling rate of 20 degrees C./min or higher.
Claim 11
Dependent Claim
20 words
A process as defined in any one of claims 1-4, wherein heat-treating is carried out at least at one stage.
Claim 12
Dependent Claim
17 words
A process as defined in claim 10, wherein heat-treating is carried out in two or more stages.
Claim 13
Dependent Claim
35 words
A process as defined in any one of claims 1-4, wherein the heat-treating is carried out by cooling the sintered body at a cooling rate of 0.2-20 degrees C./min from 800 to 400 degrees C.
Claim 14
Dependent Claim
30 words
A process as defined in claim 11, wherein heat-treating at a subsequent stage following a preceding stage is carried out at a temperature lower than that of the preceding stage.
Claim 15
Dependent Claim
26 words
A process as defined in claim 11, wherein the heat-treating at the first stage is carried out at a temperature of 800 degrees C. or higher.
Claim 16
Dependent Claim
28 words
A process as defined in claim 13, wherein the heat-treating at a second or further stage is carried out at a temperature of 800 degrees C. or less.
Claim 17
Dependent Claim
23 words
A process as defined in claim 12, wherein said cooling procedure is carried out subsequent to the sintering or any preceding heat-treating stage.
Claim 18
Dependent Claim
22 words
A process as defined in claim 1, wherein the heat-treating is carried out in a vacuum, or a reducing or inert atmosphere.
Claim 19
Dependent Claim
29 words
A process as defined in claims 5 or 6, wherein the nonoxidizing or reducing atmosphere for sintering is comprised of a vacuum, an inert gas or a reducing gas.
Claim 20
Dependent Claim
21 words
A process as defined in claim 5 or 6, wherein the metallic powder is an alloy powder having said respective composition.
Claim 21
Dependent Claim
24 words
A process as defined in claim 5 or 6, wherein the metallic powder is a mixture of alloy powders making up said respective composition.
Claim 22
Dependent Claim
44 words
A process as defined in claim 5 or 6, wherein the metallic powder is a mixture of an alloy or alloys having a Fe-B-R base composition and a powdery metal having a complementary composition making up the respective final composition of said metallic powder.
Claim 23
Dependent Claim
24 words
A process as defined in claim 21, wherein said powdery metal comprises an alloy or alloys of the componental elements of said final composition.
Claim 24
Dependent Claim
19 words
A process as defined in claim 21, wherein said powdery metal comprises a componental elements of said final composition.
Claim 25
Dependent Claim
17 words
A process as defined in claim 9, wherein the cooling rate is 100 degrees C./min or higher.
Claim 26
Dependent Claim
16 words
A process as defined in claim 2 or 4, wherein Co is no more than 35%.
Claim 27
Dependent Claim
16 words
A process as defined in claim 2 or 4, wherein Co is no more than 25%.
Claim 28
Dependent Claim
15 words
A process as defined in claim 2 or 4, wherein Co is 5% or more.
Claim 29
Dependent Claim
29 words
A process as defined in claim 6, wherein R is 12-16% and B is 6-18% and wherein the magnet has a maximum energy product of at least 7 MGOe.
Claim 30
Dependent Claim
30 words
A process as defined in claim 3, wherein the additional element M comprises at least one selected from the group consisting of V, Nb, Ta, Mo, W, Cr and Al.
Claim 31
Dependent Claim
22 words
A process as defined in claim 10, wherein the heat-treating is carried out at a temperature between 450 and 800 degrees C.
Claim 32
Dependent Claim
21 words
A process as defined claim 30, wherein the heat-treating is carried out at a temperature between 500 and 700 degrees C.
Claim 33
Dependent Claim
21 words
A process as defined in claim 10, wherein the heat-treating is carried out approximately under an isothermic condition at each stage.
Claim 34
Dependent Claim
22 words
A process as defined in claim 24, wherein the sintered body is cooled down to temperature of 800 degrees C. or less.
Claim 35
Dependent Claim
13 words
A product which is produced by the process as defined in claim 5.
Claim 36
Dependent Claim
13 words
A product which is produced by the process as defined in claim 6.
Claim 37
Dependent Claim
18 words
A process as defined in any one of claims 1-4, wherein Si does not exceed 5 atomic percent.
Claim 38
Dependent Claim
31 words
A process as defined in claims 1 or 3, wherein at least 50 vol percent of the sintered body is occupied by ferromagnetic FeBR type compound having a tetragonal crystal structure.
Claim 39
Dependent Claim
31 words
A process as defined in claims 2 or 4, wherein at least 50 vol percent of the sintered body is occupied by ferromagnetic FeCoBR type compound having a tetragonal crystal structure.
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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) | 1989-07-21 | 1990-01-20 | 1990-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-21 | 1994-01-20 | 1994-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-21 | 1998-01-20 | 1998-07-22 | $7700.00 | Window Closed / Lapsed |