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IRON-BASED SUPERCONDUCTING PERMANENT MAGNET AND METHOD OF MANUFACTURE

Foreign code F180009584
File No. K04404WO
Posted date Nov 7, 2018
Country WIPO
International application number 2016US025648
International publication number WO 2016161336
Date of international filing Apr 1, 2016
Date of international publication Oct 6, 2016
Priority data
  • 201562141659 (Apr 1, 2015) US
Title IRON-BASED SUPERCONDUCTING PERMANENT MAGNET AND METHOD OF MANUFACTURE
Abstract The present invention provides for polycrystalline superconducting permanent magnets which are synthesized of doped superconducting (AE) Fe2As2 compounds, where AE denotes an alkaline earth metal, such as Ba, Sr, Mg or Ca. The superconducting permanent magnets of the present invention can be magnetized in their superconducting state by induced currents, resulting in trapped magnetization that scales with the size of the bulk material. The magnitude of the trapped field has been demonstrated to be over 1 T and is predicted to be over 10 T if the technology is scaled, which is much higher than the capabilities of permanent magnets and other superconducting polycrystalline bulks currently known in the art.
Outline of related art and contending technology BACKGROUND OF THE INVENTION
Permanent magnets are only capable of generating magnetic fields of up to approximately 1 Tesla, thereby rendering them inadequate for applications that rely on higher magnetic fields, such as generators, motors, flywheels, magnetic levitation, magnetic resonance imaging (MRI) and research magnets. The generation of magnetic fields above 1 Tesla requires the use of electromagnets, which greatly increases the implementation cost of these technologies.
Since the discovery of iron-based superconductors in 2008, a tremendous amount of research has been focused on the synthesis and study of these superconductors. Much of the research has been driven by reports of properties that are very appealing for applications, including low anisotropy (around 1-2), high upper critical fields (HC2) (in excess of 90 T) and intrinsic critical current densities (above 1 MAcm-2 (0 T, 4.2 K)). Unfortunately, soon after their discovery the grain boundaries in these iron-based superconductor materials were observed to block current, similar to rare-earth barium cuprate (REBCO) materials such as YBa2Cu3O7-x (YBCO), but to a somewhat lesser extent. Remarkably, fine-grain, randomly oriented K-doped BaFe2As2 (Ba122) has been synthesized with global critical current density around 10 kAcnv2 (4.2 K, 10 T) and textured tapes of K-doped Ba122 and SrFe2As2 (Sr122) have now been produced that raise Jc by another order of magnitude.
While mechanically reinforced superconducting REBCO (Gd-Ba-Cu-O) materials are known in the art that produce record levels of trapped magnetic fields (up to 17.6 Tesla), these magnetically reinforced superconducting materials are limited in size (radius < 50mm) because grain boundaries in the material block current flow, forcing samples of the material to be grown as single crystals to eliminate the grain boundaries. In contrast the superconductor, MgEfe is not subject to intrinsic current blocking and as such, can be manufactured as large diameter polycrystalline bulks to trap magnetic fields. However, the trapped magnetic field of MgEfc has been shown to be limited to around 3T, which is inadequate for high magnetic field applications. Accordingly, what is needed in the art is a superconducting material having geometric versatility and improved magnetic field trapping of high magnetic fields at lower temperatures.
Scope of claims [claim1]
1. A superconducting permanent magnet comprising an Fe-based polycrystal.
[claim2]
2. The superconducting permanent magnet of claim 1 , wherein the magnet exhibits a magnetic field greater than about 1 T at a temperature of less than about 40K.
[claim3]
3. The superconducting permanent magnet of claim 1 , wherein the polycrystal comprises a square lattice of Fe forming a layered structure.
[claim4]
4. The superconducting permanent magnet of claim 1 , wherein the polycrystal may further comprise one or more of anion elements, including As, P, S, Se, Te, F or O.
[claim5]
5. The superconducting permanent magnet of claim 1 , wherein a crystalline grain of the polycrystal is smaller than about 10 μm.
[claim6]
6. The superconducting permanent magnet of claim 1 , wherein the polycrystal may include an untextured polycrystalline compound.
[claim7]
7. The superconducting permanent magnet of claim 1 , wherein the polycrystal may include a textured polycrystalline compound.
[claim8]
8. The superconducting permanent magnet of claim 1 , wherein a magnetic field is distributed spatially and temporally substantially homogeneously within a defined area of the permanent magnet.
[claim9]
9. The superconducting permanent magnet of claim 1 , wherein the polycrystal comprises a polycrystalline compound exhibiting a Vickers hardness of greater than about 1 GPa.
[claim10]
10. The superconducting permanent magnet of claim 1 , wherein the polycrystal comprises a polycrystalline compound exhibiting a fracture toughness of greaterthan about 1 MPa m05
.
[claim11]
11. The superconducting permanent magnet of claim 1 , wherein the magnet is characterized in that in a planar surface perpendicular to magnetic field lines, the shortest distance from a center of the magnetic field lines to an edge of the planar surface is within a range of about 1 mm to a about 10,000 mm.
[claim12]
12. The superconducting permanent magnet of claim 1 , wherein the permanent magnet forms a composite with a conducting material or an insulating material.
[claim13]
13. A superconducting permanent magnet comprising an Fe-based polycrystal, the magnet exhibiting a magnetic field greater than about 1 T at a temperature of less than about 40 K, the polycrystal of the magnet further comprising:
a square lattice of Fe forming a layered structure;
one or more of anion elements, including As, P, S, Se, Te, F or O; and wherein a crystalline grain of the polycrystal is smaller than about 10 μm.
[claim14]
14. A method of manufacturing a superconducting permanent magnet comprising an Fe- based polycrystal, the method comprising:
preparing an Fe-based powder;
pressing the Fe-based powder into a first container;
heat-treating the Fe-based powder in a second container to provide an Fe-based polycrystal; and
magnetizing the Fe-based polycrystal to provide a superconducting permanent magnet comprising an Fe-based polycrystal at a temperature of less than about 40K.
[claim15]
15. The method of claim 14, wherein the first container and the second container are the same containers.
[claim16]
16. The method of claim 14, wherein the first container and the second container are different containers.
[claim17]
17. The method of claim 14, wherein magnetizing the Fe-based polycrystalline to provide an a superconducting permanent magnet comprising an Fe-based polycrystal further comprises, magnetizing the Fe-based polycrystal using a magnetic field, a pulsed magnetic field, an electric field or an electromagnetic field.
[claim18]
18. The method of claim 14, wherein the Fe-based polycrystal comprises a square lattice of Fe forming a layered structure.
[claim19]
19. The method of claim 14, wherein the Fe-based polycrystal may further comprise one or more of anion elements, including As, P, S, Se, Te, F or O.
[claim20]
20. The method of claim 14, wherein the Fe-based polycrystal may further comprise a crystalline grain smaller than about 10 μιη.
  • Applicant
  • ※All designated countries except for US in the data before July 2012
  • THE FLORIDA STATE UNIVERSITY RESEARCH FOUNDATION, INC.
  • JAPANESE SCIENCE AND TECHNOLOGY AGENCY
  • Inventor
  • WEISS, Jeremy
  • YAMAMOTO, Akiyasu
  • HELLSTROM, Eric
IPC(International Patent Classification)
Specified countries National States: AE AG AL AM AO AT AU AZ BA BB BG BH BN BR BW BY BZ CA CH CL CN CO CR CU CZ DE DK DM DO DZ EC EE EG ES FI GB GD GE GH GM GT HN HR HU ID IL IN IR IS JP KE KG KN KP KR KZ LA LC LK LR LS LU LY MA MD ME MG MK MN MW MX MY MZ NA NG NI NO NZ OM PA PE PG PH PL PT QA RO RS RU RW SA SC SD SE SG SK SL SM ST SV SY TH TJ TM TN TR TT TZ UA UG US UZ VC VN ZA ZM ZW
ARIPO: BW GH GM KE LR LS MW MZ NA RW SD SL SZ TZ UG ZM ZW
EAPO: AM AZ BY KG KZ RU TJ TM
EPO: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
OAPI: BF BJ CF CG CI CM GA GN GQ GW KM ML MR NE SN ST TD TG
Reference ( R and D project ) PRESTO New Materials Science and Element Strategy AREA
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