US5009706A
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Rare-earth antisotropic powders and magnets and their manufacturing processes
Assignee: Nippon Steel Corp
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Filing: 1990-07-18
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Granted: 1991-04-23
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Expires: 2010-07-18
Abstract
Abstract Rare-earth alloy anisotropic powders consist of, in atomic percent, over 12 percent and not more than 20 percent of R (R is at least one on neodymium and praseodymium or at least one of them and or more rare-earth elements), not less than 4 percent and not more than 10 percent of boron, not less than 0.05 percent and not more than 5 percent of copper and the rest that consists of iron and unavoidable impurities. Up to 20 percent of the iron contained is replaceable with cobalt. The alloy powders are made up of flat crystal grains having mean thickness h (the shortest measure), d not smaller than 0.01 mu m and not larger than 0.5 mu m and ratio d/h not smaller than 2, where d is the means measure of the grains taken at right angles to the widthwide direction thereof, and the alloy powders are magnetically anisotropic. Each rare-earth alloy anisotropic powder is prepared by melting an R-Fe-B-Cu alloy, putting thin ribbons prepared by quenching the melt or a powder prepared by grinding the thin ribbons in a metal container, hermetically sealing the metal container after replacing its inner atmosphere with a vacuum or an inert gas atmosphere, and rolling the thin ribbons or powder, together with the metal container, at a temperature not lower than 500 DEG C. and not higher than 900 DEG C. Rare-earth alloy anisotropic magnets are made by kneading and forming the rare-earth alloy anisotropic powders with not less than 10 percent and not more than 50 percent by volume of resin or by hot-compressing the rare-earth alloy anisotropic powders.
Inventors
- 👤 Hiroaki Sakamoto
- 👤 Masahiro Fujikura
- 👤 Toshio Mukai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:12
CPC Classifications
C; C22; C22C; C22C29/00; C22C29/14; 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; H01F1/0576
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
140 words
A rare-earth alloy anisotropic powder consisting essentially of, in atomic percent, over 12 percent and not more than 20 percent of R (R is at least one of neodymium and praseodymium or at least one of them and one or more rare-earth elements), not less than 4 percent and not more than 10 percent of boron, not less than 0.05 percent and not more than 5 percent of copper and the rest that consists essentially of iron and unavoidable impurities, the alloy powder being made up of flat crystal grains having mean thickness h (the shortest measure), d not smaller than 0.01 μm and not larger than 0.5 μm and ratio d/h not smaller than 2, d being the mean measure of the grains taken at right angles to the widthwise direction thereof, and the alloy powder being magnetically anisotropic.
Claim 2
Dependent Claim
140 words
A rare-earth alloy anisotropic powder consisting essentially of, in atomic percent, over 12 percent and not more than 20 percent of R (R is at least one of neodymium and praseodymium or at least one of them and one or more rare-earth elements), not less than 4 percent and not more than 10 percent of boron, not less than 0.05 percent and not more than 5 percent of copper and the rest that consists essentially of iron and unavoidable impurities, the alloy powder being made up of flat crystal grains having mean thickness h (the shortest measure), d not smaller than 0.01 μm and not larger than 0.5 μm and ratio d/h not smaller than 2, d being the mean measure of the grains taken at right angles to the widthwise direction thereof, and the alloy powder being magnetically anisotropic.
Claim 3
Dependent Claim
24 words
A rare-earth alloy anisotropic powder according to claim 1, in which up to 20 atomic percent of the iron contained is replaced with cobalt.
Claim 4
Dependent Claim
33 words
A rare-earth alloy anisotropic powder according to claims 1 or 2, in which the residual magnetic flux density in the direction of the axis of easy magnetization is not lower than 9 kG.
Claim 5
Dependent Claim
35 words
A rare-earth alloy anisotropic magnet consisting of a rare-earth alloy anisotropic powder according to claims 1 or 2 and not less than 10 percent and not more than 50 percent, both by volume, of resin.
Claim 6
Dependent Claim
22 words
A rare-earth alloy anisotropic magnet consisting of a hot-compressed product of a rare-earth alloy anisotropic powder according to claims 1 or 2.
Claim 7
Dependent Claim
166 words
A process for preparing a rare-earth alloy anisotropic powder comprising the steps of: melting an alloy consisting essentially of, in atomic percent, over 12 percent and not more than 20 percent of R (R is at least one of neodymium and praseodymium or at least one of them and one or more rare-earth elements), not less than 4 percent and not more than 10 percent of boron, not less than 0.05 percent and not more than 5 percent of copper and the rest that consists essentially of iron and unavoidable impurities; making thin ribbons made up of fine grains by quenching the melted alloy; putting the thin ribbons or a powder obtained by grinding the thin ribbons into a metal container and hermetically sealing the metal container after replacing the inner atmosphere thereof with a vacuum or an inert atmosphere; and rolling the thin ribbons or powder together with the metal container at a temperature not lower than 500° C. and not higher than 900° C.
Claim 8
Dependent Claim
166 words
A process for preparing a rare-earth alloy anisotropic powder comprising the steps of: melting an alloy consisting essentially of, in atomic percent, over 12 percent and not more than 20 percent of R (R is at least one of neodymium and praseodymium or at least one of them and one or more rare-earth elements), not less than 4 percent and not more than 10 percent of boron, not less than 0.05 percent and not more than 5 percent of copper and the rest that consists essentially of iron and unavoidable impurities; making thin ribbons made up of fine grains by quenching the melted alloy; putting the thin ribbons or a powder obtained by grinding the thin ribbons into a metal container and hermetically sealing the metal container after replacing the inner atmosphere thereof with a vacuum or an inert atmosphere; and rolling the thin ribbons or powder together with the metal container at a temperature not lower than 500° C. and not higher than 900° C.
Claim 9
Dependent Claim
28 words
A process for preparing a rare-earth alloy anisotropic powder according to claim 6 in which up to 20 atomic percent of the iron contained is replaced with cobalt.
Claim 10
Dependent Claim
37 words
A process for preparing a rare-earth alloy anisotropic powder according to claims 6 or 7 in which the thin ribbons or powder is preliminarily formed between said steps of making thin ribbons and sealing the metal container.
Claim 11
Dependent Claim
47 words
A process for preparing a rare-earth alloy anisotropic powder according to claims 6 or 7 in which the thin ribbons or powder is preliminarily worked, together with the metal container, at a temperature lower than 800° C. between said steps of sealing the metal container and rolling.
Claim 12
Dependent Claim
37 words
A process for preparing a rare-earth alloy anisotropic powder according to claims 6 or 7 in which the product obtained by rolling the thin ribbons or powder together with the metal container is ground into a powder.
Claim 13
Dependent Claim
37 words
A process for preparing a rare-earth alloy anisotropic powder according to claims 6 or 7 in which the rolled product is heat treated at a temperature not lower than 400° C. and not higher than 800° C.
Claim 14
Dependent Claim
42 words
A process for preparing a rare-earth alloy anisotropic powder according to claims 6 or 7 in which the powder obtained by grinding the rolled product is heat treated at a temperature not lower than 400° C. and not higher than 800° C.
Claim 15
Dependent Claim
194 words
A process for making a rare-earth alloy anisotropic magnet comprising the steps of: melting an alloy consisting of, in atomic percent, over 12 percent and not more than 20 percent of R (R is at least one of neodymium and praseodymium or at least one of them and one or more rare-earth elements), not less than 4 percent and not more than 10 percent of boron, not less than 0.05 percent and not more than 5 percent of copper and the rest that consists of iron and unavoidable impurities; making thin ribbons made up of fine grains by quenching the melted alloy; putting the thin ribbons or a powder obtained by grinding the thin ribbons into a metal container and hermetically sealing the metal container after replacing the inner gas atmosphere thereof with a vacuum or an inert atmosphere; rolling the thin ribbons or powder together with the metal container at a temperature not lower than 500° C. and not higher than 900° C.; and mixing a powder prepared by grinding the rolled product with not less than 10 percent and not more than 50 percent by volume of resin into a desired shape.
Claim 16
Dependent Claim
194 words
A process for making a rare-earth alloy anisotropic magnet comprising the steps of: melting an alloy consisting of, in atomic percent, over 12 percent and not more than 20 percent of R (R is at least one of neodymium and praseodymium or at least one of them and one or more rare-earth elements), not less than 4 percent and not more than 10 percent of boron, not less than 0.05 percent and not more than 5 percent of copper and the rest that consists of iron and unavoidable impurities; making thin ribbons made up of fine grains by quenching the melted alloy; putting the thin ribbons or a powder obtained by grinding the thin ribbons into a metal container and hermetically sealing the metal container after replacing the inner gas atmosphere thereof with a vacuum or an inert atmosphere; rolling the thin ribbons or powder together with the metal container at a temperature not lower than 500° C. and not higher than 900° C.; and mixing a powder prepared by grinding the rolled product with not less than 10 percent and not more than 50 percent by volume of resin into a desired shape.
Claim 17
Dependent Claim
178 words
A process for making a rare-earth alloy anisotropic magnet comprising the steps of: melting an alloy consisting of, in atomic percent, over 12 percent and not more than 20 percent of R (R is at least one of neodymium and praseodymium or at least one of them and one or more rare-earth elements), not less than 4 percent and not more than 10 percent of boron, not less than 0.05 percent and not more than 5 percent of copper and the rest that consists of iron and unavoidable impurities; making thin ribbons made up of fine grains by quenching the melted alloy; putting the thin ribbons or a powder obtained by grinding the thin ribbons into a metal container and hermetically sealing the metal container after replacing the inner gas atmosphere thereof with a vacuum or an inert atmosphere; rolling the thin ribbons or powder together with the metal container at a temperature not lower than 500° C. and not higher than 900° C.; and hot-compressing a powder prepared by grinding the rolled product into a desired shape.
Claim 18
Dependent Claim
178 words
A process for making a rare-earth alloy anisotropic magnet comprising the steps of: melting an alloy consisting of, in atomic percent, over 12 percent and not more than 20 percent of R (R is at least one of neodymium and praseodymium or at least one of them and one or more rare-earth elements), not less than 4 percent and not more than 10 percent of boron, not less than 0.05 percent and not more than 5 percent of copper and the rest that consists of iron and unavoidable impurities; making thin ribbons made up of fine grains by quenching the melted alloy; putting the thin ribbons or a powder obtained by grinding the thin ribbons into a metal container and hermetically sealing the metal container after replacing the inner gas atmosphere thereof with a vacuum or an inert atmosphere; rolling the thin ribbons or powder together with the metal container at a temperature not lower than 500° C. and not higher than 900° C.; and hot-compressing a powder prepared by grinding the rolled product into a desired shape.
Claim 19
Dependent Claim
37 words
A process for preparing a rare-earth alloy anisotropic magnet according to claims 13 or 14 in which the thin ribbons or powder is preliminarily formed between said steps of making thin ribbons and sealing the metal container.
Claim 20
Dependent Claim
47 words
A process for preparing a rare-earth alloy anisotropic magnet according to claims 13 or 14 in which the thin ribbons or powder is preliminarily worked, together with the metal container, at a temperature lower than 800° C. between said steps of sealing the metal container and rolling.
Claim 21
Dependent Claim
37 words
A process for preparing a rare-earth alloy anisotropic magnet according to claims 13 or 14 in which the rolled product is heat treated at a temperature not lower than 400° C. and not higher than 800° C.
Claim 22
Dependent Claim
42 words
A process for preparing a rare-earth alloy anisotropic magnet according to claims 13 or 14 in which the powder obtained by grinding the rolled product is heat treated at a temperature not lower than 400° C. and not higher than 800° C.
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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) | 1994-04-22 | 1994-10-22 | 1995-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-22 | 1998-10-22 | 1999-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-22 | 2002-10-22 | 2003-04-23 | $7700.00 | Window Closed / Lapsed |