Claims
- 1. 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.
- 2. The method of claim 1, wherein the alloy is selected from the group consisting of FeNdB, FeBSi, FeNiBSi, CoBSi, CoFeBSi, FeCrBSi, and FeNiCrBSi alloys.
- 3. The method of claim 1, wherein the alloy is melted in an inert gas atmosphere.
- 4. 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.
- 5. The method of claim 1, wherein the deposited alloy contains less than about 1,000 parts per million oxygen.
- 6. The method of claim 1, wherein the substrate is liquid cooled.
- 7. The method of claim 1, wherein the deposited alloy has greater than 20% crystallinity.
- 8. The method of claim 7, wherein the droplets are just about to or have begun to solidify at the moment they impact the substrate.
- 9. 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.
- 10. The method of claim 1, wherein the deposited alloy is substantially amorphous.
- 11. The method of claim 10, wherein substantially all of the droplets are fully liquid upon impact with the substrate.
- 12. The method of claim 10, wherein the droplets remain substantially free of crystallites upon impact with the substrate.
- 13. 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.
- 14. The method of claim 10, wherein the impacted droplets have cooled sufficiently to remain amorphous prior to being impacted with additional droplets.
- 15. 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.
- 16. 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.degree. K./sec.
- 17. The method of claim 10, wherein the deposited alloy is at least about 95% amorphous.
Parent Case Info
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. Ser. No. 07/629,077, filed Dec. 17, 1990, which is a continuation of U.S. Ser. No. 06/922,730, filed Oct. 24, 1986, now abandoned, which is a continuation of U.S. Ser. No. 06/766,051, filed Aug. 15, 1985, now abandoned.
U.S. GOVERNMENT RIGHTS
The U.S. government has rights in this invention by virtue of U.S. Army Research Office Contract No. DAAG-84-K-0171.
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4496395 |
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4585473 |
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Continuations (2)
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Number |
Date |
Country |
Parent |
922730 |
Oct 1986 |
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Parent |
766051 |
Aug 1985 |
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Continuation in Parts (1)
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Number |
Date |
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629077 |
Dec 1990 |
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