US5000800A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Permanent magnet and method for producing the same
Assignee: Individual
•
Filing: 1989-03-09
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Granted: 1991-03-19
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Expires: 2009-03-09
Abstract
Abstract An Nd-Fe-B sintered magnet which has 0.5 %/°C. or more of temperature-coefficient of coercive force (iHc) and a composition that R=11-18 at % (R is one or more rare-earth elements except for Dy, with the proviso of 80 at % ≦(Nd+Pr)/R≦100 at %), B=6-12 at %, and balance of Fe and Co (with the proviso of Co is 25 at % or less relative to the total of Co and Fe (including 0 % of Co)) and impurities, is improved to have 15 kOe or more of coercive force (iHc) by means of further containing 2-6 at % of V and modifying 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 phase but forms a finely dispersed V-T-B compound minority phase (T is fe, and in a case of containing Co, T is Fe and Co).
Inventors
- 👤 Masato Sagawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 08:12
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: 24
Claim 1
Independent Claim
149 words
An Nd-Fe-B sintered magnet having a temperature coefficient of coercive force iHc of 0.5%/° C. or greater and consisting essentially of 11 to 18 at % R, where R is one or more rare earth elements except for Dy and the total amount of Nd and Pr is at least 80 at % of the total rare earth elements, 6 to 12 at % B, Fe, impurities, and from 2 to 6 at % V, wherein B in excess of a stoichiometric amount for a R 2 Fe 14 B compound-phase in the sintered magnet is essentially in the form of a finely dispersed V-Fe-B compound minority phase, and the sintered magnet is essentially free of a R Fe 4 B 4 compound minority phase, the sintered magnet exhibiting a maximum energy product BH(max) of at least 20 MGOe and a coercive force iHc of at least 15 kOe.
Claim 2
Dependent Claim
149 words
An Nd-Fe-B sintered magnet having a temperature coefficient of coercive force iHc of 0.5%/° C. or greater and consisting essentially of 11 to 18 at % R, where R is one or more rare earth elements except for Dy and the total amount of Nd and Pr is at least 80 at % of the total rare earth elements, 6 to 12 at % B, Fe, impurities, and from 2 to 6 at % V, wherein B in excess of a stoichiometric amount for a R 2 Fe 14 B compound-phase in the sintered magnet is essentially in the form of a finely dispersed V-Fe-B compound minority phase, and the sintered magnet is essentially free of a R Fe 4 B 4 compound minority phase, the sintered magnet exhibiting a maximum energy product BH(max) of at least 20 MGOe and a coercive force iHc of at least 15 kOe.
Claim 3
Dependent Claim
18 words
An Nd-Fe-B sintered magnet according to claim 1, further consisting essentially of up to 3 at % aluminum.
Claim 4
Dependent Claim
104 words
An Nd-Fe-B sintered magnet according to claim 1 or 2, wherein the magnet further consists essentially of at least one of M 1 , M 2 and M 3 , wherein M 1 is up to 4 at % of one or more of elements selected from the group consisting of Cr, Mo and W, M 2 is up to 3 at % of one or more elements selected from the group consisting of Nb, Ta and Ni, and M 3 is up to 2 at % of one or more elements selected from the group consisting of Ti, Zr, Hf, Si and Mn.
Claim 5
Dependent Claim
23 words
An Nd-Fe-B sintered magnet according to claim 1 or 2, having a coercive force iHc at 140° C. of at least 5 kOe.
Claim 6
Dependent Claim
23 words
An Nd-Fe-B sintered magnet according to claim 1 or 2, having a coercive force iHc at 200° C. of at least 5 kOe.
Claim 7
Dependent Claim
164 words
An Nd-Fe-B sintered magnet having a temperature coefficient of coercive force iHc of 0.5%/° C. or greater and consisting essentially of 11 to 18 at % R, where R is one or more rare earth elements, Dy is up to 4 at % of the magnet and the total amount of Nd, Pr and Dy is at least 80 at % of the total rare earth elements; 6 to 12 at % B; Fe, impurities and from 2 to 6 at % V, wherein B in excess of a stoichiometric amount for a R 2 Fe 14 B compound-phase in the sintered magnet is essentially in the form of a finely dispersed V-Fe-B compound minority phase, and the sintered magnet is essentially free of a RFe 4 B 4 compound minority phase. the sintered magnet exhibiting a maximum energy product BH(max) of at least 20 MGOe and a coercive force iHc of 15+3x kOe (where x is the amount of Dy in at %).
Claim 8
Dependent Claim
164 words
An Nd-Fe-B sintered magnet having a temperature coefficient of coercive force iHc of 0.5%/° C. or greater and consisting essentially of 11 to 18 at % R, where R is one or more rare earth elements, Dy is up to 4 at % of the magnet and the total amount of Nd, Pr and Dy is at least 80 at % of the total rare earth elements; 6 to 12 at % B; Fe, impurities and from 2 to 6 at % V, wherein B in excess of a stoichiometric amount for a R 2 Fe 14 B compound-phase in the sintered magnet is essentially in the form of a finely dispersed V-Fe-B compound minority phase, and the sintered magnet is essentially free of a RFe 4 B 4 compound minority phase. the sintered magnet exhibiting a maximum energy product BH(max) of at least 20 MGOe and a coercive force iHc of 15+3x kOe (where x is the amount of Dy in at %).
Claim 9
Dependent Claim
18 words
An Nd-Fe-B sintered magnet according to claim 6, further consisting essentially of up to 3 at % aluminum.
Claim 10
Dependent Claim
104 words
An Nd-Fe-B sintered magnet according to claim 6 or 7, wherein the magnet further consists essentially of at least one of M 1 , M 2 and M 3 , wherein M 1 is up to 4 at % of one or more of elements selected from the group consisting of Cr, Mo and W, M 2 is up to 3 at % of one or more elements selected from the group consisting of Nb, Ta and Ni, and M 3 is up to 2 at % of one or more elements selected from the group consisting of Ti, Zr, Hf, Si and Mn.
Claim 11
Dependent Claim
22 words
An Nd-Fe-B magnet according to claim 6 or 7, having a coercive force iHc of at least 5+2x kOe at 140° C.
Claim 12
Dependent Claim
22 words
An Nd-Fe-B magnet according to claim 6 or 7, having a coercive force iHc of at least 5 kOe at 200° C.
Claim 13
Dependent Claim
172 words
An Nd-Fe-B sintered magnet having a temperature coefficient of coercive force iHc of 0.5%/° C. or greater and comprising 11 to 18 at % R, where R is one or more rare earth elements except for Dy and the total amount of Nd and Pr is at least 80 at % of the total rare earth elements, 6 to 12 at % B, Fe, Co in an amount of up to 25 at % of the total Fe and Co which is effective to enhance the Curie temperature of the magnet, impurities, and from 2 to 6 at % V, wherein B in excess of a stoichiometric amount for a R 2 Fe 14 B compound-phase in the sintered magnet is essentially in the form of a finely dispersed V-(Fe,Co)-B compound minority phase, and the sintered magnet is essentially free of a RFe 4 B 4 compound minority phase, the sintered magnet exhibiting a maximum energy product BH(max) of at least 20 MGOe and coercive force iHc of at least 15 kOe.
Claim 14
Dependent Claim
172 words
An Nd-Fe-B sintered magnet having a temperature coefficient of coercive force iHc of 0.5%/° C. or greater and comprising 11 to 18 at % R, where R is one or more rare earth elements except for Dy and the total amount of Nd and Pr is at least 80 at % of the total rare earth elements, 6 to 12 at % B, Fe, Co in an amount of up to 25 at % of the total Fe and Co which is effective to enhance the Curie temperature of the magnet, impurities, and from 2 to 6 at % V, wherein B in excess of a stoichiometric amount for a R 2 Fe 14 B compound-phase in the sintered magnet is essentially in the form of a finely dispersed V-(Fe,Co)-B compound minority phase, and the sintered magnet is essentially free of a RFe 4 B 4 compound minority phase, the sintered magnet exhibiting a maximum energy product BH(max) of at least 20 MGOe and coercive force iHc of at least 15 kOe.
Claim 15
Dependent Claim
18 words
An Nd-Fe-B sintered magnet according to claim 11, further consisting essentially of up to 3 at % aluminum.
Claim 16
Dependent Claim
104 words
An Nd-Fe-B sintered magnet according to claim 11 or 12, wherein the magnet further consists essentially of at least one of M 1 , M 2 and M 3 , wherein M 1 is up to 4 at % of one or more of elements selected from the group consisting of Cr, Mo and W, M 2 is up to 3 at % of one or more elements selected from the group consisting of Nb, Ta and Ni, and M 3 is up to 2 at % of one or more elements selected from the group consisting of Ti, Zr, Hf, Si and Mn.
Claim 17
Dependent Claim
23 words
An Nd-Fe-B sintered magnet according to claim 11 or 12, having a coercive force iHc at 140° C. of at least 5 kOe.
Claim 18
Dependent Claim
23 words
An Nd-Fe-B sintered magnet according to claim 11 or 12, having a coercive force iHc at 200° C. of at least 5 kOe.
Claim 19
Dependent Claim
190 words
An Nd-Fe-B sintered magnet having a temperature coefficient of coercive force iHc of 0.5%/° C. or greater and comprising 11 to 18 at % R, where R is one or more rare earth elements, Dy is up to 4 at % of the magnet and the total amount of Nd, Pr and Dy is at least 80 at % of the total rare earth elements; 6 to 12 at % B; Fe, Co in an amount of up to 25 at % of the total Fe and Co which is effective to enhance the Curie temperature of the magnet, impurities and from 2 to 6 at % V, wherein B in excess of a stoichiometric amount for a R 2 Fe 14 B compound-phase in the sintered magnet is essentially in the form of a finely dispersed V-(Fe, Co)-B compound minority phase, and the sintered magnet is essentially free of a RFe 4 B 4 compound minority phase, the sintered magnet exhibiting a maximum energy product BH(max) of at least 20 MGOe and a coercive force iHc of 15+3x kOe (where x is the amount of Dy in at %).
Claim 20
Dependent Claim
190 words
An Nd-Fe-B sintered magnet having a temperature coefficient of coercive force iHc of 0.5%/° C. or greater and comprising 11 to 18 at % R, where R is one or more rare earth elements, Dy is up to 4 at % of the magnet and the total amount of Nd, Pr and Dy is at least 80 at % of the total rare earth elements; 6 to 12 at % B; Fe, Co in an amount of up to 25 at % of the total Fe and Co which is effective to enhance the Curie temperature of the magnet, impurities and from 2 to 6 at % V, wherein B in excess of a stoichiometric amount for a R 2 Fe 14 B compound-phase in the sintered magnet is essentially in the form of a finely dispersed V-(Fe, Co)-B compound minority phase, and the sintered magnet is essentially free of a RFe 4 B 4 compound minority phase, the sintered magnet exhibiting a maximum energy product BH(max) of at least 20 MGOe and a coercive force iHc of 15+3x kOe (where x is the amount of Dy in at %).
Claim 21
Dependent Claim
18 words
An Nd-Fe-B sintered magnet according to claim 16, further consisting essentially of up to 3 at % aluminum.
Claim 22
Dependent Claim
104 words
An Nd-Fe-B sintered magnet according to claim 16 or 17, wherein the magnet further consists essentially of at least one of M 1 , M 2 and M 3 , wherein M 1 is up to 4 at % of one or more of elements selected from the group consisting of Cr, Mo and W, M 2 is up to 3 at % of one or more elements selected from the group consisting of Nb, Ta and Ni, and M 3 is up to 2 at % of one or more elements selected from the group consisting of Ti, Zr, Hf, Si and Mn.
Claim 23
Dependent Claim
22 words
An Nd-Fe-B magnet according to claim 16 or 17, having a coercive force iHc of at least 5+2x kOe at 140° C.
Claim 24
Dependent Claim
22 words
An Nd-Fe-B magnet according to claim 16 or 17, having a coercive force iHc of at least 5 kOe at 200° 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) | 1994-03-18 | 1994-09-17 | 1995-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-18 | 1998-09-17 | 1999-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-18 | 2002-09-17 | 2003-03-19 | $7700.00 | Window Closed / Lapsed |