US5783263A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for forming nanoparticles
Assignee: Carnegie Mellon University
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Filing: 1996-06-05
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Granted: 1998-07-21
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Expires: 2016-06-05
Abstract
Abstract A metal or alloy nanoparticle is provided which exhibits hysteresis at room temperature having a carbon coating. The nanoparticle has a diameter in the range of approximately 0.5 to 50 nm, and may be crystalline or amorphous. The metal, alloy, or metal carbide nanoparticle is formed by preparing graphite rods which are packed with the magnetic metal or alloy or an oxide of the metal or alloy. The packed graphite rods are subjected to a carbon arc discharge to produce soot containing metal, alloy, or metal carbide nanoparticles and non-magnetic species. The soot is subsequently subjected to a magnetic field gradient to separate the metal, alloy, or metal carbide nanoparticles from the non-magnetic species.
Inventors
- 👤 Sara Majetich
- 👤 Michael McHenry
- 👤 Joseph Artman
- 👤 Stuart Staley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 05:06
CPC Classifications
C; C01; C01B; C01B32/00; C01B32/90; C01B32/907; B; B22; B22F; B22F1/00; B22F1/05; B22F1/054; B22F1/16; B22F9/00; B22F9/02; B22F9/14; B22F9/16; B22F9/18; B22F9/20; B82; B82Y; B82Y25/00; B82Y30/00; H; H01; H01F; H01F1/00; H01F1/0036; H01F1/0045; H01F1/0054; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/047; H01F1/053; H01F1/055; H01F1/0551; B22F2999/00; C01P; C01P2002/00; C01P2002/02; C01P2002/70; C01P2004/00; C01P2004/01; C01P2004/04; C01P2004/60; C01P2004/64; C01P2004/80; C01P2006/00; C01P2006/42; C22; C22C; C22C26/00; C22C2026/001; Y; Y10; Y10S; Y10S977/00; Y10S977/70; Y10S977/773; Y10S977/775; Y10S977/832; Y10S977/838; Y10S977/84; Y10S977/89; Y10S977/90
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
79 words
A method for forming a metal or alloy nanoparticle comprising the steps of: a. preparing a graphite rod, said graphite rod being packed with said metal or alloy or an oxide of said metal or alloy; b. subjecting said packed graphite rod to a carbon arc discharge to produce soot containing magnetic metal alloy nanoparticles and non-magnetic species; and c. applying a magnetic field gradient to said soot to separate said magnetic metal alloy nanoparticles from said non-magnetic species.
Claim 2
Independent Claim
79 words
A method for forming a metal or alloy nanoparticle comprising the steps of: a. preparing a graphite rod, said graphite rod being packed with said metal or alloy or an oxide of said metal or alloy; b. subjecting said packed graphite rod to a carbon arc discharge to produce soot containing magnetic metal alloy nanoparticles and non-magnetic species; and c. applying a magnetic field gradient to said soot to separate said magnetic metal alloy nanoparticles from said non-magnetic species.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein said nanoparticle is one of a ferromagnetic and paramagnetic compound.
Claim 4
Dependent Claim
13 words
The method of claim 2 wherein said nanoparticle exhibits hysteresis at room temperature.
Claim 5
Dependent Claim
12 words
The method of claim 3 wherein said metal alloy is samarium cobalt.
Claim 6
Dependent Claim
32 words
The method of claim 4 wherein said samarium cobalt is in the form of at least one of SmCo 5 , Sm 2 Co 7 , and Sm 2 Co 17 .
Claim 7
Dependent Claim
13 words
The method of claim 3 wherein said metal alloy is a manganese-aluminum compound.
Claim 8
Dependent Claim
11 words
The method of claim 6 wherein said manganese-aluminum compound is manganese-aluminum-carbide.
Claim 9
Independent Claim
80 words
A method for separating carbon coated magnetic nanoparticles comprising: forming a mixture of carbon coated magnetic and nonmagnetic nanoparticles by carbon arc discharge; creating a magnetic field gradient having a magnetic force sufficient to suspend the magnetic nanoparticles when the mixture is passed through the magnetic field gradient; passing the mixture through the magnetic field gradient to suspend the magnetic nanoparticles and separate the magnetic nanoparticles from the mixture; and, removing the mixture that passed through the magnetic field gradient.
Claim 10
Independent Claim
80 words
A method for separating carbon coated magnetic nanoparticles comprising: forming a mixture of carbon coated magnetic and nonmagnetic nanoparticles by carbon arc discharge; creating a magnetic field gradient having a magnetic force sufficient to suspend the magnetic nanoparticles when the mixture is passed through the magnetic field gradient; passing the mixture through the magnetic field gradient to suspend the magnetic nanoparticles and separate the magnetic nanoparticles from the mixture; and, removing the mixture that passed through the magnetic field gradient.
Claim 11
Dependent Claim
23 words
The method of claim 8, further comprising: releasing the suspended magnetic nanoparticles from the magnetic field gradient; and, collecting the released magnetic nanoparticles.
Claim 12
Dependent Claim
29 words
The method of claim 9, further comprising repeating said method of claim 8 with the magnetic nanoparticles that were suspended and released from the magnetic field gradient and collected.
Claim 13
Dependent Claim
44 words
The method of claim 8, wherein: said creating a magnetic field gradient comprises positioning a pair of strong magnets near a separator to create a magnetic field gradient within the separator; and, said step of passing further comprises passing the mixture through the separator.
Claim 14
Dependent Claim
19 words
The method of claim 11, further comprising separating the magnets and the separator to release the suspended magnetic nanoparticles.
Claim 15
Dependent Claim
33 words
The method of claim 8, wherein the magnetic nanoparticles have a magnetic moment, and said method further comprises varying the magnetic field gradient to segregate the magnetic nanoparticles according to the magnetic moment.
Claim 16
Dependent Claim
31 words
The method of claim 8, wherein said passing comprises dropping the mixture such that a gravitational force will act on the mixture and pass the mixture through the magnetic field gradient.
Claim 17
Dependent Claim
14 words
The method of claim 8, wherein said magnetic nanoparticles exhibit hysteresis at room temperature.
Claim 18
Independent Claim
106 words
A method of producing separated carbon-coated magnetic nanoparticles, comprising the steps of: subjecting a magnetic metal, alloy or an oxide of a magnetic metal or alloy to a carbon coating process to form a mixture of carbon coated magnetic nanoparticles and nonmagnetic material; creating a magnetic field gradient having a magnetic force sufficient to suspend the carbon coated magnetic nanoparticles when the mixture is passed through the magnetic field gradient; passing the mixture through the magnetic field gradient to suspend the carbon coated magnetic nanoparticles and separate the carbon coated magnetic nanoparticles from the mixture; and, removing the mixture that passed through the magnetic field gradient.
Claim 19
Independent Claim
106 words
A method of producing separated carbon-coated magnetic nanoparticles, comprising the steps of: subjecting a magnetic metal, alloy or an oxide of a magnetic metal or alloy to a carbon coating process to form a mixture of carbon coated magnetic nanoparticles and nonmagnetic material; creating a magnetic field gradient having a magnetic force sufficient to suspend the carbon coated magnetic nanoparticles when the mixture is passed through the magnetic field gradient; passing the mixture through the magnetic field gradient to suspend the carbon coated magnetic nanoparticles and separate the carbon coated magnetic nanoparticles from the mixture; and, removing the mixture that passed through the magnetic field gradient.
Claim 20
Dependent Claim
36 words
The method of claim 16, wherein said step of subjecting further comprises the step of grinding the mixture to form a fine powder prior to said step of passing the mixture through the magnetic gradient field.
Claim 21
Dependent Claim
55 words
The method of claim 16, wherein the suspended carbon coated magnetic nanoparticles contain an amount of fullerenes, and said method further comprises the steps of: releasing the suspended carbon coated magnetic nanoparticles from the magnetic field gradient; collecting the released carbon coated magnetic nanoparticles; and, extracting the fullerenes from the collected carbon coated magnetic nanoparticles.
Claim 22
Dependent Claim
22 words
The method of claim 16, wherein the carbon coated magnetic nanoparticles are selected from the group consisting of paramagnetic and ferromagnetic compounds.
Claim 23
Dependent Claim
21 words
The method of claim 19, wherein the carbon coated magnetic nanoparticles are selected from the group consisting of the transition metals.
Claim 24
Dependent Claim
24 words
The method of claim 20, wherein the carbon coated magnetic nanoparticles are selected from the group consisting of iron, cobalt, nickel, and manganese bismuth.
Claim 25
Dependent Claim
14 words
The method of claim 21, wherein the carbon coated magnetic nanoparticles are samarium cobalt.
Claim 26
Dependent Claim
26 words
The method of claim 22, wherein samarium cobalt is of the form SmCo 5 , Sm 2 Co 7 , and Sm 2 Co 17 .
Claim 27
Dependent Claim
14 words
The method of claim 19, wherein the carbon coated magnetic nanoparticles are manganese-aluminum compounds.
Claim 28
Dependent Claim
11 words
The method of claim 24, wherein the manganese-aluminum compounds are manganese-aluminum-carbides.
Claim 29
Dependent Claim
28 words
The method of claim 19, wherein the carbon coated magnetic nanoparticles are selected from the group consisting of the rare earth metals except for lanthanum, lutetium and promethium.
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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) | 2001-07-20 | 2002-01-19 | 2002-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-07-20 | 2006-01-19 | 2006-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-07-20 | 2010-01-19 | 2010-07-21 | $7700.00 | Window Closed / Lapsed |