US4760966A
Expired / Lapsed
US
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Method of comminuting rare earth magnet alloys into fine particles
Assignee: United States Department of the Army
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Filing: 1987-08-28
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Granted: 1988-08-02
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Expires: 2007-08-28
Abstract
Abstract Rare earth magnet alloys are comminuted into fine particles at room tempeure up to about 400° C. by placing the alloy into a vessel and pressurizing the vessel, hydriding the alloy, depressurizing the alloy to atmospheric pressure after the absorption of hydrogen and evacuating the vessel so that the absorbed hydrogen is given up leaving microfissures in the alloy, and comminution of the sample.
Inventors
- 👤 Robert D. Finnegan
- 👤 Joseph P. Klimek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:00
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; H01F1/0573; B; B22; B22F; B22F9/00; B22F9/02; B22F9/023
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
75 words
Method of comminuting rare earth magnet alloys into fine particles at room temperature up to about 400° C., said method including the steps of: (A) placing the alloy into a vessel and pressurizing the vessel, (B) hydriding the alloy, (C) depressurizing the alloy to atmospheric pressure after the absorption of hydrogen, and (D) evacuating the vessel so that the absorbed hydrogen is given up leaving microfissures in the alloy, and comminution of the sample alloy.
Claim 2
Dependent Claim
75 words
Method of comminuting rare earth magnet alloys into fine particles at room temperature up to about 400° C., said method including the steps of: (A) placing the alloy into a vessel and pressurizing the vessel, (B) hydriding the alloy, (C) depressurizing the alloy to atmospheric pressure after the absorption of hydrogen, and (D) evacuating the vessel so that the absorbed hydrogen is given up leaving microfissures in the alloy, and comminution of the sample alloy.
Claim 3
Dependent Claim
26 words
Method according to claim 1 wherein about sixty to one hundred cycles of pressurization and pulling of vacuum and of absorbing and desorbing are carried out.
Claim 4
Dependent Claim
19 words
Method according to claim 2 wherein the cycles of absorbing and desorbing are carried out using a microprocessor-controlled system.
Claim 5
Dependent Claim
21 words
Method according to claim 3 wherein 20 percent of the larger particles are reduced to less than 37 microns in size.
Claim 6
Dependent Claim
20 words
Method according to claim 1 wherein the rare earth magnet alloy comminuted is Nd 14 Fe 77 B 8 .
References Cited (Backward Citations)
US4641787A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-02 | 1992-02-01 | 1992-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-02 | 1996-02-01 | 1996-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-02 | 2000-02-01 | 2000-08-02 | $7700.00 | Window Closed / Lapsed |