US4995905A
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US
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Permanent magnet having improved heat-treatment characteristics and method for producing the same
Assignee: Individual
•
Filing: 1989-05-23
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Granted: 1991-02-26
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Expires: 2009-05-23
Abstract
Abstract When V is added to an Nd--Fe--B sintered magnet so as to modify the minority phase such that B in excess of a stoichiometric composition of R 2 Fe 14 B compound-phase, essentially does not form RFe 4 B 4 -compound minority phases but forms a finely dispersed V--T--B compound minority phase (T is Fe, and in a case containing Co, T is Fe and Co), the coercive force (iHc) is enhanced to 15 kOe or more but becomes very sensitive to heat treatment temperature. This drawback is eliminated by the addition of from 0.01 to 1 at % of Cu.
Inventors
- 👤 Masato Sagawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:35
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
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
132 words
An R--Fe--B magnet comprising 11-18 at % R, wherein R is one or more rare-earth elements excluding Dy, with the proviso that at least 80 at % and up to 100 at % of the total R are Nd, Pr or mixtures thereof; 6-12 at % B, and the balance is Fe and Co such that Co is 0-25 at % and impurities. further comprising V in an amount of from 2 to 6 at % and Cu in an amount of from 0.01 to 1 at %, a V--T--B compound minority phase, wherein T is Fe, Co or mixtures thereof, being finely dispersed in the magnet and the magnet exhibiting a maximum energy product (BH) max of 20 MGOe or more and a coercive force (iHc) of 15 kOe or more.
Claim 2
Dependent Claim
132 words
An R--Fe--B magnet comprising 11-18 at % R, wherein R is one or more rare-earth elements excluding Dy, with the proviso that at least 80 at % and up to 100 at % of the total R are Nd, Pr or mixtures thereof; 6-12 at % B, and the balance is Fe and Co such that Co is 0-25 at % and impurities. further comprising V in an amount of from 2 to 6 at % and Cu in an amount of from 0.01 to 1 at %, a V--T--B compound minority phase, wherein T is Fe, Co or mixtures thereof, being finely dispersed in the magnet and the magnet exhibiting a maximum energy product (BH) max of 20 MGOe or more and a coercive force (iHc) of 15 kOe or more.
Claim 3
Dependent Claim
17 words
An R--Fe--B sintered magnet according to claim 1, further comprising 3 at % or less of aluminum.
Claim 4
Dependent Claim
48 words
An R--Fe--B magnet according to claim 1, further comprising 0-4 at % of one or more of Cr, Mo or W, 0-3 at % of one or more of Nb, Ta, or Ni, and 0-2 at % of one or more of Ti, Zr, Hf, Si or Mn.
Claim 5
Dependent Claim
198 words
An R--Fe--B magnet comprising 11-18 at % R, wherein R is one or more rare-earth elements, with the proviso that at least 80 at % and up to 100 at % of the total R are R 1 , R 2 or mixtures thereof, wherein R 1 is Nd, Pr or mixtures thereof and R 2 is Dy, the content of Dy being 0-4 at % of the magnet; 6-12 at % B, and the balance is Fe and Co such that Co is 0-25 at % or less of the total of Co and Fe and impurities. further comprising V in an amount of from 2 to 6 at % and Cu in an amount of from 0.01 to 1 at %, a V--T--B compound minority phase, wherein T is Fe, Co or mixtures thereof, being finely dispersed in the magnet and the magnet exhibiting a maximum energy product (BH)max of 20 MGOe or more and a coercive force (iHc) greater than or equal to 15+3x kOe, x being the Dy content of the magnet in at %, with the proviso that when 15+3x exceeds 21, the coercive force of the magnet is 21 kOe or more.
Claim 6
Dependent Claim
198 words
An R--Fe--B magnet comprising 11-18 at % R, wherein R is one or more rare-earth elements, with the proviso that at least 80 at % and up to 100 at % of the total R are R 1 , R 2 or mixtures thereof, wherein R 1 is Nd, Pr or mixtures thereof and R 2 is Dy, the content of Dy being 0-4 at % of the magnet; 6-12 at % B, and the balance is Fe and Co such that Co is 0-25 at % or less of the total of Co and Fe and impurities. further comprising V in an amount of from 2 to 6 at % and Cu in an amount of from 0.01 to 1 at %, a V--T--B compound minority phase, wherein T is Fe, Co or mixtures thereof, being finely dispersed in the magnet and the magnet exhibiting a maximum energy product (BH)max of 20 MGOe or more and a coercive force (iHc) greater than or equal to 15+3x kOe, x being the Dy content of the magnet in at %, with the proviso that when 15+3x exceeds 21, the coercive force of the magnet is 21 kOe or more.
Claim 7
Dependent Claim
17 words
An R--Fe--B sintered magnet according to claim 4, further comprising 3 at % or less of aluminum.
Claim 8
Dependent Claim
48 words
An R--Fe--B magnet according to claim 4, further comprising 0-4 at % of one or more of Cr, Mo or W, 0-3 at % of one or more of Nb, Ta, or Ni, and 0-2 at % of one or more of Ti, Zr, Hf, Si or Mn.
Claim 9
Independent Claim
141 words
A method for producing a R--Fe--B sintered magnet, which consists essentially of a structure of an R 2 Fe 14 B compound phase and a V--T--B compound minority phase wherein T is Fe, Co or mixtures thereof, the magnet exhibiting a coercive force (iHc) of 15 kOe or more, comprising a step of providing a starting material comprising 11-18 at % R, wherein R is one or more rare-earth elements excluding Dy, with the proviso that at least 80 at % and up to 100 at % of the total R are Nd, Pr or mixtures thereof; 6-12 at % B, 2-6 at % V and 0.01-1 at % Cu, and the balance is Fe and Co such that Co is 0-25 at % and impurities, a sintering step and a step of subsequently heat treating to produce the sintered magnet.
Claim 10
Independent Claim
141 words
A method for producing a R--Fe--B sintered magnet, which consists essentially of a structure of an R 2 Fe 14 B compound phase and a V--T--B compound minority phase wherein T is Fe, Co or mixtures thereof, the magnet exhibiting a coercive force (iHc) of 15 kOe or more, comprising a step of providing a starting material comprising 11-18 at % R, wherein R is one or more rare-earth elements excluding Dy, with the proviso that at least 80 at % and up to 100 at % of the total R are Nd, Pr or mixtures thereof; 6-12 at % B, 2-6 at % V and 0.01-1 at % Cu, and the balance is Fe and Co such that Co is 0-25 at % and impurities, a sintering step and a step of subsequently heat treating to produce the sintered magnet.
Claim 11
Dependent Claim
19 words
A method according to claim 7, wherein the R--Fe--B magnet further comprises 3 at % or less of aluminum.
Claim 12
Dependent Claim
50 words
A method according to claim 7, wherein the magnet further comprises 0-4 at % of one or more of Cr, Mo or W, 0-3 at % of one or more of Nb, Ta, or Ni, and 0-2 at % of one or more of Ti, Zr, Hf, Si or Mn.
Claim 13
Independent Claim
195 words
A method for producing a R--Fe--B sintered magnet, which consists essentially of a structure of an R 2 Fe 14 B compound phase and a V--T--B compound minority phase wherein T is Fe, Co or mistures thereof, comprising a step of providing a starting material comprising 11-18 at % R, wherein R is one or more rare-earth elements, with the proviso that at least 80 at % and up to 100 at % of the total R are R 1 , R 2 or mixtures thereof, wherein R 1 is Nd, Pr or mixtures thereof and R 2 is Dy, the content of Dy being 0-4 at % of the magnet; 6-12 at % B, 2-6 at % V and 0.01-1 at % Cu, and the balance is Fe and Co such that Co is 0-25 at % and impurities, a sintering step and a step of subsequently heat treating to produce the sintered magnet, the magnet exhibiting a coercive force (iHc) of 15+3x kOe or more, where x is the Dy content in at %, with the proviso that when 15+3x exceeds 21, the coercive force of the magnet is 21 kOe or more.
Claim 14
Independent Claim
195 words
A method for producing a R--Fe--B sintered magnet, which consists essentially of a structure of an R 2 Fe 14 B compound phase and a V--T--B compound minority phase wherein T is Fe, Co or mistures thereof, comprising a step of providing a starting material comprising 11-18 at % R, wherein R is one or more rare-earth elements, with the proviso that at least 80 at % and up to 100 at % of the total R are R 1 , R 2 or mixtures thereof, wherein R 1 is Nd, Pr or mixtures thereof and R 2 is Dy, the content of Dy being 0-4 at % of the magnet; 6-12 at % B, 2-6 at % V and 0.01-1 at % Cu, and the balance is Fe and Co such that Co is 0-25 at % and impurities, a sintering step and a step of subsequently heat treating to produce the sintered magnet, the magnet exhibiting a coercive force (iHc) of 15+3x kOe or more, where x is the Dy content in at %, with the proviso that when 15+3x exceeds 21, the coercive force of the magnet is 21 kOe or more.
Claim 15
Dependent Claim
19 words
A method according to claim 10, wherein the R--Fe--B magnet further comprises 3 at % or less of aluminum.
Claim 16
Dependent Claim
50 words
A method according to claim 10, wherein the magnet further comprises 0-4 at % of one or more of Cr, Mo or W, 0-3 at % of one or more of Nb, Ta, or Ni, and 0-2 at % of one or more of Ti, Zr, Hf, Si, or Mn.
Claim 17
Dependent Claim
48 words
An R--Fe--B magnet according to claim 2, further comprising 0-4 at % of one or more of Cr, Mo or W, 0-3 at % of one or more of Nb, Ta, or Ni, and 0-2 at % of one or more of Ti, Zr, Hf, Si or Mn.
Claim 18
Dependent Claim
48 words
An R--Fe--B magnet according to claim 5, further comprising 0-4 at % of one or more of Cr, Mo or W, 0-3 at % of one or more of Nb, Ta, or Ni, and 0-2 at % of one or more of Ti, Zr, Hf, Si or Mn.
Claim 19
Dependent Claim
50 words
A method according to claim 8, wherein the magnet further comprises 0-4 at % of one or more of Cr, Mo or W, 0-3 at % of one or more of Nb, Ta, or Ni, and 0-2 at % of one or more of Ti, Zr, Hf, Si or Mn.
Claim 20
Dependent Claim
50 words
A method according to claim 11, wherein the magnet further comprises 0-4 at % of one or more of Cr, Mo or W, 0-3 at % of one or more of Nb, Ta, or Ni, and 0-2 at % of one or more of Ti, Zr, Hf, Si or Mn.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-02-25 | 1994-08-27 | 1995-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-25 | 1998-08-27 | 1999-02-26 | $3760.00 | Window Closed / Lapsed |
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