US4793874A
Expired / Lapsed
US
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Permanent magnetic alloy and method of manufacturing the same
Assignee: Toshiba Corp
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Filing: 1987-02-06
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Granted: 1988-12-27
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Expires: 2007-02-06
Abstract
Abstract A permanent magnetic alloy essentially consists of 10 to 40% by weight of R, 0.1 to 8% by weight of boron, 50 to 300 ppm by weight of oxygen and the balance of iron, where R is at least one component selected from the group consisting of yttrium and the rare-earth elements. An alloy having this composition has a high coercive force I H C and a high residual magnetic flux density and therefore has a high maximum energy product.
Inventors
- 👤 Tetsuhiko Mizoguchi
- 👤 Koichiro Inomata
- 👤 Toru Higuchi
- 👤 Isao Sakai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:30
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: 10
Claim 1
Independent Claim
115 words
A method of manufacturing a permanent magnet, comprising the steps of: melting a raw material essentially consisting of 10 to 40% by weight of R, 0.1 to 8% by weight of boron, 50 to 300 ppm by weight of oxygen and the balance of iron, where R is at least one component selected from the group consisting of yttrium and rare-earth elements; casting a melt of the raw material to obtain a block; pulverizing the block to a powder of an average particle size of 2 to 10 μm; compressing the powder while applying a magnetic field; and sintering a resultant compact at a temperature of 1,000° to 1,200° C. for 0.5 to 5 hours.
Claim 2
Independent Claim
115 words
A method of manufacturing a permanent magnet, comprising the steps of: melting a raw material essentially consisting of 10 to 40% by weight of R, 0.1 to 8% by weight of boron, 50 to 300 ppm by weight of oxygen and the balance of iron, where R is at least one component selected from the group consisting of yttrium and rare-earth elements; casting a melt of the raw material to obtain a block; pulverizing the block to a powder of an average particle size of 2 to 10 μm; compressing the powder while applying a magnetic field; and sintering a resultant compact at a temperature of 1,000° to 1,200° C. for 0.5 to 5 hours.
Claim 3
Dependent Claim
42 words
A method according to claim 1, wherein the raw material further includes not more than 20% by weight of at least one element selected from the group consisting of cobalt, chromium, aluminum, titanium, zirconium, hafnium, niobium, tantalum, vanadium, manganese, molybdenum, and tungsten.
Claim 4
Dependent Claim
20 words
A method according to claim 2, wherein the raw material further includes not more than 20% by weight of cobalt.
Claim 5
Dependent Claim
19 words
A method according to claim 3, wherein the raw material further includes 5 to 20% by weight of cobalt.
Claim 6
Dependent Claim
26 words
A method according to claim 1, wherein the raw material further includes not more than 5% by weight of at least one of aluminum and titanium.
Claim 7
Dependent Claim
25 words
A method according to claim 5, wherein the raw material further includes 0.2 to 5% by weight of at least one of aluminum and titanium.
Claim 8
Dependent Claim
35 words
A method according to claim 1, wherein the raw material further includes not more than 5% by weight of cobalt and not more than 5% by weight of at least one of aluminum and titanium.
Claim 9
Dependent Claim
33 words
A method according to claim 1, wherein the raw material further includes 5 to 20% by weight of cobalt and 0.2 to 5% by weight of at least one of aluminum and titanium.
Claim 10
Dependent Claim
25 words
A method according to claim 8, further comprising aging the sintered body at a temperature of 400° to 1,100° C. for 1 to 10 hours.
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) | 1991-12-27 | 1992-06-27 | 1992-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-27 | 1996-06-27 | 1996-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-27 | 2000-06-27 | 2000-12-27 | $7700.00 | Window Closed / Lapsed |