US5225004A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bulk rapidly solifidied magnetic materials
Assignee: Massachusetts Institute of Technology
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Filing: 1991-04-30
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Granted: 1993-07-06
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Expires: 2011-04-30
Abstract
Abstract Bulk rapidly solidified magnetic materials having a density of greater than 90%, a thickness of at least 250 microns, and preferably a low oxygen content, are produced by a liquid dynamic compaction process which, depending upon the chosen operating conditions, can yield materials ranging from crystalline to partially crystalline to amorphous. The materials so produced are directly useful, i.e. without having to be reduced to a powder and consolidated into a shape, to produce permanent magnets. When the materials are amorphous, they can be directly used as soft magnetic materials and for other purposes
Inventors
- 👤 Robert C. O'Handley
- 👤 Nicholas J. Grant
- 👤 Yutaka Hara
- 👤 Enrique J. Lavernia
- 👤 Tetsuji Harada
- 👤 Teiichi Ando
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:31
CPC Classifications
B; B22; B22F; B22F3/00; B22F3/115; B22F9/00; B22F9/002; B22F9/008; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/047; H01F1/053; H01F1/055; H01F1/057; H01F1/0571; H01F1/0574; H01F1/12; H01F1/14; H01F1/147; H01F1/153; H01F1/15333; H01F1/15341; H01F1/1535; B22F2998/00
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
290 words
A method for producing a bulk permanent magnet having a thickness of at least 250 microns and a density of at least about 90%, which comprises the steps of: (i) melting in a container an alloy capable of exhibiting magnetic properties of the formula: (Fe.sub.1-x T.sub.x).sub.a (Nd.sub.1-y R.sub.y).sub.b (B.sub.1-z M.sub.z).sub.c wherein T is selected from Co, Ni, Cu, Mn, Cr, V, Ti, and any combination thereof; wherein R is selected from Pr, Pm, Sm, Tb, Dy, Ho, Er, Tm, and any combination thereof; wherein M is selected from Si, C, P, and any combination thereof; wherein x is from 0 to 1; y is from 0 to 1; and z is from 0 to 1; and wherein a+b+c=100 atom % and "a" is from about 60 to about 95 atom %; "b" is from about 0 to about 30 atom %; and "c" is from 0 to about 25 atom %; (ii) atomizing the molten alloy to form droplets by directing pressurized jets of an inert gas onto the molten alloy after it passes through a delivery means exiting the container; (iii) depositing the alloy droplets onto a metallic substrate positioned at a distance away from the container opening wherein (a) a majority of the alloy droplets are in a liquid or semi-liquid state when they are deposited onto the substrate, (b) the droplets are rapidly quenched upon contact with the substrate or prior rapidly quenched droplets thereon and (c) the deposition continues until the deposit is at least about 250 microns thick; and (iv) removing the deposit from the substrate and, without forming a powder of the deposit, annealing the deposit at a sufficiently elevated temperature and for a sufficient period of time to produce a bulk permanent magnet.
Claim 2
Independent Claim
290 words
A method for producing a bulk permanent magnet having a thickness of at least 250 microns and a density of at least about 90%, which comprises the steps of: (i) melting in a container an alloy capable of exhibiting magnetic properties of the formula: (Fe.sub.1-x T.sub.x).sub.a (Nd.sub.1-y R.sub.y).sub.b (B.sub.1-z M.sub.z).sub.c wherein T is selected from Co, Ni, Cu, Mn, Cr, V, Ti, and any combination thereof; wherein R is selected from Pr, Pm, Sm, Tb, Dy, Ho, Er, Tm, and any combination thereof; wherein M is selected from Si, C, P, and any combination thereof; wherein x is from 0 to 1; y is from 0 to 1; and z is from 0 to 1; and wherein a+b+c=100 atom % and "a" is from about 60 to about 95 atom %; "b" is from about 0 to about 30 atom %; and "c" is from 0 to about 25 atom %; (ii) atomizing the molten alloy to form droplets by directing pressurized jets of an inert gas onto the molten alloy after it passes through a delivery means exiting the container; (iii) depositing the alloy droplets onto a metallic substrate positioned at a distance away from the container opening wherein (a) a majority of the alloy droplets are in a liquid or semi-liquid state when they are deposited onto the substrate, (b) the droplets are rapidly quenched upon contact with the substrate or prior rapidly quenched droplets thereon and (c) the deposition continues until the deposit is at least about 250 microns thick; and (iv) removing the deposit from the substrate and, without forming a powder of the deposit, annealing the deposit at a sufficiently elevated temperature and for a sufficient period of time to produce a bulk permanent magnet.
Claim 3
Dependent Claim
24 words
The method of claim 1, wherein the alloy is selected from the group consisting of FeNdB, FeBSi, FeNiBSi, CoBSi, CoFeBSi, FeCrBSi, and FeNiCrBSi alloys.
Claim 4
Dependent Claim
15 words
The method of claim 1, wherein the alloy is melted in an inert gas atmosphere.
Claim 5
Dependent Claim
25 words
The method of claim 1, wherein the atomizing inert gas is supplied to the pressurized jets at a pressure of about 100 to 1000 psi.
Claim 6
Dependent Claim
18 words
The method of claim 1, wherein the deposited alloy contains less than about 1,000 parts per million oxygen.
Claim 7
Dependent Claim
11 words
The method of claim 1, wherein the substrate is liquid cooled.
Claim 8
Dependent Claim
14 words
The method of claim 1, wherein the deposited alloy has greater than 20% crystallinity.
Claim 9
Dependent Claim
24 words
The method of claim 7, wherein the droplets are just about to or have begun to solidify at the moment they impact the substrate.
Claim 10
Dependent Claim
35 words
The method of claim 7, wherein the temperature of the top surface of the substrate and the deposit produced thereon is at least about or greater than the crystallization temperature of the alloy being deposited.
Claim 11
Dependent Claim
12 words
The method of claim 1, wherein the deposited alloy is substantially amorphous.
Claim 12
Dependent Claim
19 words
The method of claim 10, wherein substantially all of the droplets are fully liquid upon impact with the substrate.
Claim 13
Dependent Claim
18 words
The method of claim 10, wherein the droplets remain substantially free of crystallites upon impact with the substrate.
Claim 14
Dependent Claim
33 words
The method of claim 10, wherein at the time of impact with the substrate the droplets have been sufficiently undercooled to prevent formation of crystalline nuclei on cooling through their glass transition temperature.
Claim 15
Dependent Claim
22 words
The method of claim 10, wherein the impacted droplets have cooled sufficiently to remain amorphous prior to being impacted with additional droplets.
Claim 16
Dependent Claim
32 words
The method of claim 10, wherein the temperature of the top surface of the substrate and the deposit thereon is maintained at less than the crystallization temperature of the alloy being deposited.
Claim 17
Dependent Claim
57 words
The method of claim 10, wherein the atomizing inert gas pressure is about 100 to about 1,000 psi; the metal alloy mass flow rate is about 0.2 to about 2 kg/min.; the metallic substrate is about 20 to 60 cm from the container opening; the metallic substrate has a quench capacity of greater than about 1000° K./sec.
Claim 18
Dependent Claim
15 words
The method of claim 10, wherein the deposited alloy is at least about 95% amorphous.
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) | 1996-07-05 | 1997-01-04 | 1997-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-07-05 | 2001-01-04 | 2001-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-07-05 | 2005-01-04 | 2005-07-06 | $7700.00 | Window Closed / Lapsed |