Treatment In A Magnetic Field Patents (Class 148/103)
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Patent number: 4975411Abstract: A ceramic superconductor is made by consolidating a plurality of metals and a chalcogen and applying a magnetic field during the consolidation operation.Type: GrantFiled: May 19, 1987Date of Patent: December 4, 1990Assignee: Fonar CorporationInventors: Gordon T. Danby, Charles E. Brukl, Lawrence A. Minkoff
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Patent number: 4968347Abstract: A high energy rare earth-ferromagnetic metal permanent magnet is disclosed which is characterized by improved intrinsic coercivity and is made by forming a particulate mixture of a permanent magnet alloy comprising one or more rare earth elements and one or more ferromagnetic metals and forming a second particulate mixture of a sintering alloy consisting essentially of 92-98 wt. % of one or more rare earth elements selected from the class consisting of Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures of two or more of such rare earth elements, and 2-8 wt. % of one or more alloying metals selected from the class consisting of Al, Nb, Zr, V, Ta, Mo, and mixtures of two or more of such metals. The permanent magnet alloy particles and sintering aid alloy are mixed together and magnetically oriented by immersing the mixture in an axially aligned magnetic field while cold pressing the mixture.Type: GrantFiled: November 22, 1988Date of Patent: November 6, 1990Assignee: The United States of America as represented by the United States Department of EnergyInventors: Ramamoorthy Ramesh, Gareth Thomas
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Patent number: 4954186Abstract: Permanent magnets are prepared by a method comprising mixing a particular rare earth-iron-boron alloy with particulate aluminum, aligning the magnetic domains of the mixture, compacting the aligned mixture to form a shape, and sintering the compacted shape.Type: GrantFiled: April 4, 1988Date of Patent: September 4, 1990Assignee: Union Oil Company of CaliforniaInventor: Mohammad H. Ghandehari
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Patent number: 4950335Abstract: A process and apparatus for producing articles for magnetic use consisting of a metal alloy in the form of a continuous strip (3) from which the articles (33) are cut out, the alloy being subjected to a heat treatment comprising at least one annealing operation carried out in the presence of a magnetic field. The annealing operation is divided into at least two successive phases, respectively a first, initiating phase in the presence of a magnetic field, carried out on the alloy in the form of a continuous strip (3) as it unwinds, and a second phase of ageing carried out on the separated articles (33) obtained from the strip (3) which has undergone the first phase. The invention enables the production of articles, in particular, for the electrotechnical industry.Type: GrantFiled: May 25, 1988Date of Patent: August 21, 1990Assignee: Imphy S. A.Inventor: Georges Couderchon
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Patent number: 4919732Abstract: New Iron-Neodymium-Boron base alloys containing hafnium diboride, zirconium diboride and titanium diboride are disclosed. The alloys are subjected to rapid solidification processing technique which produces cooling rates between 10.sup.5 to 10.sup.7 .degree.C.second. The as-quenched filament, ribbon or particulate, powder etc. consists predominantly of a single amorphous phase. The amorphous powder is heat treated above the crystallization temperature into microcrystalline powder which is subsequently ground into ultrafine particles with average size less than 5 microns by attritor or hammer mill. The ultrafine powder particles are simultaneously aligned and cold compacted by the combined action of an applied magnetic field and uniaxial pressure. The green compacts containing particles with mostly aligned grains with their easy magnetization axes parallel to the applied field direction are sintered into bulk forms.Type: GrantFiled: July 25, 1988Date of Patent: April 24, 1990Assignee: Kubota Ltd.Inventors: Choong-Jin Yang, Ranjan Ray
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Patent number: 4920326Abstract: A method of magnetizing high energy rare earth alloy magnets by applying a magnetic field while heating the magnetic alloy.Type: GrantFiled: January 26, 1989Date of Patent: April 24, 1990Assignee: Eastman Kodak CompanyInventor: Ashok K. Agarwala
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Patent number: 4913745Abstract: A method is disclosed for producing a rare earth metal-transition metal-boron (R-T-B) bonded magnet with a magnetic anisotropy. R-T-B alloy ribbons and/or ribbon-like flakes containing R.sub.2 T.sub.14 B fine crystals are prepared with a thickness of 20-1,000 .mu.m by rapidly-quenching method. The ribbons and/or flakes are crushed and ground into a magnetic powder of particle sizes smaller than the value of the ribbon thickness. The magnetic powder is mixed with binder agent and formed into desired bulk-shape body in an aligning magnetic field to produce the bonded magnet with the magnetic anisotropy. In order to improve the magnetic properties, the ribbons and/or flakes can be heat-treated at a temperature of 650.degree.-950.degree. C. The magnetic powder can also be teat-treated at a temperature of 500.degree.-700.degree. C.Type: GrantFiled: March 22, 1988Date of Patent: April 3, 1990Assignee: Tokin CorporationInventor: Tadakuni Sato
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Patent number: 4911882Abstract: The present invention relates to the preparation of permanent magnet materials of the Iron-Boron-Rare Earth type.Type: GrantFiled: February 8, 1989Date of Patent: March 27, 1990Assignee: SPS Technologies, Inc.Inventor: Frank S. Greenwald
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Patent number: 4902357Abstract: This invention concerns a heat treatment method for rare earth type permanent magnets which are primarily of the Nd-Fe-B type. With regard to these permanent magnets, which oxidize rather easily in the air, the alloy is crushed, and either compression formed in a magnetic a non-magnetic field, sintered at 900.degree. to 1,200.degree. C., and then machined into the shape desired, and then solution treated in an atmosphere of oxygen and/or nitrogen at a temperature of 900.degree. to 1,200.degree. C., and then aged at 300.degree. to 900.degree. C. in order that an oxide and/or nitride protective layer of 0.001 to 10 .mu. be formed on the surface of the permanent magnet to prevent corrosion and in order to relieve machining strain.Type: GrantFiled: April 26, 1988Date of Patent: February 20, 1990Assignee: Namiki Precision Jewel Co., Ltd.Inventor: Nobuo Imaizumi
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Patent number: 4894097Abstract: In production of rare earth type magnet, addition of Nd to Fe-Gd-metalloid base containing 2 or more of B, Si, and P, combined with solidification of molten alloy by abrupt cooling assures large coercive force and high susceptibility of the product.Type: GrantFiled: December 31, 1987Date of Patent: January 16, 1990Assignee: Yamaha CorporationInventors: Kenzaburou Iijima, Masayuki Takamura, Takeo Sata
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Patent number: 4888068Abstract: A process for manufacturing a rare earth-iron-boron alloy permanent magnet by, after sintering, keeping the sintered alloy at temperatures of 750.degree.-1000.degree. C. for 0.2-5 hours, slowly cooling it at a cooling rate of 0.3.degree.-5.degree. C./min. to temperatures between room temperature and 600.degree. C.; annealing it at temperatures of 550.degree.-700.degree. C. for 0.2-3 hours, and rapidly cooling it at a cooling rate of 20.degree.-400.degree. C./min. The permanent magnet contains a matrix, a B-rich phase and a Nd-rich phase. In grain boundaries of the matrix phases covered by bcc phases, thin, fine plates of the bcc phases projecting into the matrix phases are once increased by the first heat treatment and slow cooling and then eliminated by the annealing.Type: GrantFiled: October 4, 1985Date of Patent: December 19, 1989Assignee: Hitachi Metals, Ltd.Inventors: Masaaki Tokunaga, Minoru Endoh, Noriaki Meguro, Shigeho Tanigawa
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Patent number: 4881986Abstract: In a method for producing a rare earth metal-iron-boron (R-Fe-B) anisotropic sintered magnet from R-Fe-B alloy ribbon-like flakes, each flake is formed with a thickness of about 20-500 .mu.m and contains R.sub.2 Fe.sub.14 B crystal grains dispersed in the flake with an average grain size of 10 .mu.m or less. The flakes are ground into a powder having an average particle size less than the thickness value of the flake. The powder is magnetically aligned and compacted into a compact body which is then sintered. Thus, the anisotropic sintered magnet is obtained with a high energy product and a high anti-corrosion property. The ribbon-like flakes are prepared by the continuous splat-quenching method. Alternatively, the flakes can be prepared by spraying the molten R-Fe-B alloy in a form of particles and cooling the particles on a cooling plate into flat small pieces.Type: GrantFiled: November 25, 1987Date of Patent: November 21, 1989Assignee: Tokin CorporationInventors: Tadakuni Sato, Yuichi Tachiya
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Patent number: 4881985Abstract: A method to produce rare earth (RE), iron, boron type anisotropic permanently magnetic material includes forming magnetically isotropic coarse powder particles of melt-spun alloy with a very fine grain RE.sub.2 FE.sub.14 B phase. The particles are mixed with inert particles of a size and of a weight percentage of the mixture to separate the powder particles for preventing hot work bonding therebetween. The mixture is hot pressed to cause the magnetically isotropic particles to be compressed in a direction parallel to the press direction so as to strain the particles to cause crystallites to be oriented along a crystallographically preferred magnetic axis resulting in particles of anisotropic permanently magnetic material.Type: GrantFiled: August 5, 1988Date of Patent: November 21, 1989Assignee: General Motors CorporationInventors: Earl G. Brewer, Robert W. Lee, John J. Croat
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Patent number: 4878958Abstract: Permanent magnets are prepared by a method comprising mixing a particulate rare earth-iron-boron alloy with particulate aluminum, aligning the magnetic domains of the mixture, compacting the align mixture to form a shape, and sintering the compacted shape.Type: GrantFiled: April 4, 1988Date of Patent: November 7, 1989Assignee: Union Oil Company of CaliforniaInventor: Mohammad H. Ghandehari
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Patent number: 4875946Abstract: A heat-treatment process for producing rare earth-cobalt permanent magnets having relatively high and reproducible magnetic properties wherein one or more controlled cooling rates are applied in temperatures ranging from a sintering temperature and the isothermal annealing temperature. The controlled cooling rates are preferably divided into two steps. In the first step, the cooling rate is preferably greater than 10.degree. C./min. In the second step, the cooling rate is preferably less than 10.degree. C./min. and is ideally in the range of 2.degree.-4.degree. C./min. By the heat-treatment process of this invention, a permanent magnet having a high intrinsic coercivity of more than 20 kOe, a maximum energy product of greater than 19 MGOe, and a coercivity of greater than 8.1 kOe can be reproducibly obtained.Type: GrantFiled: February 2, 1988Date of Patent: October 24, 1989Assignee: Industrial Technology Research InstituteInventors: Shiang-Jiun Heh, Swe-Kai Chen, Fu-Teh Jin, Li-Kou Chen
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Patent number: 4857118Abstract: Permanent magnets are manufactured by grinding a magnetic phase having the composition RE.sub.2 (Fe, Co).sub.14 B with a non-magnetic phase, orienting it magnetically, densifying and then sintering it. The non-magnetic phase may be a hydride of either a rare earth metal or alloy thereof. The second phase must have a melting point lower than the magnetic phase.Type: GrantFiled: October 9, 1987Date of Patent: August 15, 1989Assignee: U.S. Philips CorporationInventors: Reinoud Van Mens, Gijsbertus W. Turk
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Patent number: 4854979Abstract: An anisotropic magnetic material formed from iron, boron and a rare-earth metal is prepared by the rapid solidification of an alloy melt of the desired composition and subsequently treated to generate magnetic anisotropy. The materials attain comparatively higher coercivity field strengths. A preliminary alloy is first prepared with the material components and cobalt is added to the alloy in such an amount that the crystallization temperature of the corresponding amorphous material system is below the Curie temperature of the crystallizing SE.sub.2 (Fe, Co).sub.14 B- phase. An intermediate product with amorphous structure is then developed from the melt of the preliminary alloy using a rapid solidification technique. Thereafter, a crystallization of the intermediate product is performed using a heat treatment at a temperature that is above the crystallization temperature but below the Curie Temperature in the presence of an external d-c magnetic field to generate the magnetic anisotropy.Type: GrantFiled: March 18, 1988Date of Patent: August 8, 1989Assignee: Siemens AktiengesellschaftInventor: Joachim Wecker
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Patent number: 4853045Abstract: In a known method of manufacturing a sintered rare earth transition metal and boron magnet body, e.g. of Nd--Fe--B, the cast alloy is comminuted by hydrogen decrepitation in an atmosphere of pure hydrogen before further comminution, pressing in a magnetic alignment field, sintering and magnetization. The use of pure hydrogen introduces a serious risk of explosion. In the improved method the hydrogen is provided mixed with a chemically non-reactive gas, suitably nitrogen, suitably in a proportion in the range 5 percent to 30 percent by volume of hydrogen, to form an explosion suppressant atmosphere in the decrepitation vessel 1. Sole FIGURE.Type: GrantFiled: February 24, 1988Date of Patent: August 1, 1989Assignee: U.S. Philips CorporationInventor: Ewoud Rozendaal
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Patent number: 4834812Abstract: Permanent magnets are prepared by a method comprising mixing a particulate rare earth-iron-boron alloy with a particulate additive metal powder, compacting the aligned mixture to form a shape, and heating the compacted shape at a temperature at least 150.degree. C. less than the sintering temperature of a rare earth-iron-boron alloy and usually in the range from about 700.degree. C. to less than 850.degree. C.Type: GrantFiled: November 2, 1987Date of Patent: May 30, 1989Assignee: Union Oil Company of CaliforniaInventor: Mohammad H. Ghandehari
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Patent number: 4826546Abstract: A process for producing permanent magnet materials, which comprises the steps of:forming an alloy powder having a mean particle size of 0.3-80 microns and composed of, in atomic percentage, 8-30% R (provided that R is at least one of rare earth elements including Y), 2-28% B, and the balance being Fe and inevitable impurities,sintering the formed body at a temperature of 900.degree.-1200.degree. C.,subjecting the sintered body to a primary heat treatment at a temperature of 750.degree.-1000.degree. C.,then cooling the resultant body to a temperature of no higher than 680.degree. C. at a cooling rate of 3.degree.-2000.degree. C./min, andfurther subjecting the thus cooled body to a secondary heat treatment at a temperature of 480.degree.-700.degree. C.35 MGOe, 40 MGOe or higher energy product can be obtained with specific compositions.Type: GrantFiled: August 13, 1987Date of Patent: May 2, 1989Assignee: Sumitomo Special Metal Co., Ltd.Inventors: Hitoshi Yamamoto, Masato Sagawa, Setsuo Fujimura, Yutaka Matsuura
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Patent number: 4818305Abstract: In the production of press molded articles, such as permanent magnets made from anisotropic powder materials, a more nearly uniform distribution of the particles is obtained by the forming of a preliminary series of articles, each being only a fraction of the length of the final product, after which the preliminary articles are combined under lengthwise pressure in a mold. Pressure may be applied as each preliminary article is added in the mold and the final article may be sintered or a plastic binder may be added and cured by heating.Type: GrantFiled: May 9, 1984Date of Patent: April 4, 1989Assignee: Magnetfabrik Bonn GmbHInventor: Erich Steingroever
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Patent number: 4818304Abstract: This invention comprises a method of increasing the magnetostrictive response of rare earth-iron (RFe) magnetostrictive alloy rods by a thermal-magnetic treatment. The rod is heated to a temperature above its Curie temperature, viz. from 400.degree. to 600.degree. C.; and, while the rod is at that temperature, a magnetic field is directionally applied and maintained while the rod is cooled, at least below its Curie temperature.Type: GrantFiled: October 20, 1987Date of Patent: April 4, 1989Assignee: Iowa State University Research Foundation, Inc.Inventors: John D. Verhoeven, O. Dale McMasters, Edwin D. Gibson, Jerome E. Ostenson, Douglas K. Finnemore
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Patent number: 4801340Abstract: A method for manufacturing a permanent magnet using alloys of the formula R(T.sub.1-y M.sub.y).sub.z, wherein R denotes one or two species of rare earth metals, including Y, T denotes transition metals, principally Fe or Fe and Co, M denotes metalloid elements, principally B, and wherein 0.02<y<0.15, and 5<z<9), to obtain permanent magnets with high orientation properties through the formation of 50-1000 .mu.m crude grains by spraying the alloys in a hot melt state using an inert gas atomization process, forming grains of less than 30 .mu.m by a mechanical pulverizing process after crystal texture in the crude grains has grown to over 30 .mu.m granules by a heat-treatment of the crude grains in a vacuum or in an inert atmosphere below 1000.degree. C., whereupon the grain powder is compression molded and heat treated at 500.degree.-900.degree. C. under a magnetic field to yield a compacted powder permanent magnet.Type: GrantFiled: June 11, 1987Date of Patent: January 31, 1989Assignee: Namiki Precision Jewel Co., Ltd.Inventors: Nobuyuki Inoue, Katsumi Takahashi, Nobuo Imaizumi
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Patent number: 4793874Abstract: 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 .sub.I H.sub.C and a high residual magnetic flux density and therefore has a high maximum energy product.Type: GrantFiled: February 6, 1987Date of Patent: December 27, 1988Assignee: Kabushiki Kaisha ToshibaInventors: Tetsuhiko Mizoguchi, Koichiro Inomata, Toru Higuchi, Isao Sakai
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Patent number: 4782994Abstract: An apparatus for the in-line annealing of amorphous strip includes feed rolls for substantially continuously feeding the strip during annealing. The strip is first fed into a nip of cooperating heated pressure rolls. The heated pressure rolls rapidly heat the strip to an annealing temperature at a rate of substantially 10.sup.2 -10.sup.4 .degree.C./second while also subjecting the strip to localized plastic deformation. Where multiple ribbons are being fed simultaneously through the heating pressure rolls, bonding occurs to produce a composite strip. The strip is fed from the pressure rolls through an in-line annealer immediately downstream from the pressure rolls. During annealing, the strip is continuously fed and maintained under tension by operation of a winding roll. The strip is annealed at a temperature of between 420.degree.-510.degree. C. for 0.01-10.0 minutes.Type: GrantFiled: July 24, 1987Date of Patent: November 8, 1988Assignee: Electric Power Research Institute, Inc.Inventors: Derek Raybould, Dulari L. Sawhney, Anthony J. Esposito
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Patent number: 4778541Abstract: Directional solidification of Bi and Mn compositions to produce magnetic single domain size MnBi particles with aligned morphologies.Type: GrantFiled: November 20, 1987Date of Patent: October 18, 1988Assignee: Grumman Aerospace CorporationInventors: Ronald G. Pirich, David J. Larson, Jr.
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Patent number: 4776902Abstract: Compositions for the production of rare earth-ferromagnetic-metal permanent magnets comprise mixtures of rare earth-ferromagnetic metal alloy powder and a lesser amount of a powdered second-phase sintering aid, wherein there is added up to about 2 percent by weight of a particulate refractory oxide, carbide, or nitride additive. Permanent magnets are prepared by mixing the components, aligning the mixture in a magnetic field, pressing and sintering. The refractory material inhibits grain growth in the second phase during sintering, improving the magnetic properties of the major phase.Type: GrantFiled: April 28, 1986Date of Patent: October 11, 1988Assignee: Union Oil Company of CaliforniaInventor: Mohammad H. Ghandehari
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Patent number: 4762574Abstract: Permanent magnets are prepared by a method comprising mixing a particulate rare earth-iron-boron alloy with a particulate rare earth oxide, aligning the magnetic domains of the mixture, compacting the aligned mixture to form a shape, and sintering the compacted shape.Type: GrantFiled: June 14, 1985Date of Patent: August 9, 1988Assignee: Union Oil Company of CaliforniaInventor: Mohammad H. Ghandehari
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Patent number: 4743311Abstract: A metal part, which may be an amorphous metal, is formed from an intermediate product comprised of at least two alloy components in powder form which have been compacted and optionally deformed such as by hammering or extrusion. The intermediate part is transformed into the metal part by a diffusion reaction. The intermediate product is produced by milling the at least two starting alloy components to form a mixture powder of particles having a predominantly layer-like structure comprising the starting alloy components. At least one of the starting alloy components is magnetic. After milling, the produced mixture powder is subjected to a magnetic field which aligns the still mobile powder particles. Thereafter, the final compacting and possible deformation takes place.Type: GrantFiled: August 8, 1986Date of Patent: May 10, 1988Assignee: Siemens AktiengesellschaftInventors: Ludwig Schultz, Karl Wohlleben
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Patent number: 4734131Abstract: A permanent-magnet material having a composition represented by the following formula;R(Co.sub.1-X-Y-.alpha.-.beta. Fe.sub.X Cu.sub.Y M.sub..alpha. M'.sub.62)A(wherein X, Y, .alpha., .beta., and A respectively represent the following numbers:0.01.ltoreq.X, 0.02.ltoreq.Y.ltoreq.0.25, 0.001.ltoreq..alpha..ltoreq.0.15,0.0001.ltoreq..beta..ltoreq.0.001, and 6.0.ltoreq.A.ltoreq.8.3,providing that the amount of Fe to be added should be less than 15% by weight, based on the total amount of the composition, and R, M, and M' respectively represent the following constituents:R: At least one element selected from the group of rare earth elements,M: At least one element selected from the group consisting of Ti, Zr, Hf, Nb, V, and Ta, andM': B or B+Si),is disclosed.Type: GrantFiled: July 21, 1987Date of Patent: March 29, 1988Assignee: Kabushiki Kaisha ToshibaInventors: Tomohisa Arai, Naoyuki Sori, Seiki Sato, Nobuo Uchida
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Patent number: 4723994Abstract: A method of forming a magnetic material. The magnetic material is a solid mass of grains, and has magnetic parameters characterized by: (1) a maximum magnetic energy product, (BH).sub.max, greater than 15 megagaussoersteds; and (2) a remanence greater than 9 kilogauss. The magnetic material is prepared by a two step solidification, heat treatment process. The solidification process is carried out by: (a) providing a molten precursor alloy; (b) atomizing the molten alloy through nozzle means to form individual droplets of the molten alloy; and (c) quenching the droplets of the molten alloy to form solid particles of the alloy. The solid particles have a morphology characterized as being one or more of (i) amorphous; (ii) microcrystalline; or (iii) polycrystalline. The grains within the solid have, at this stage of the process, an average grain characteristic dimension less than that of the heat treated magnetic material.Type: GrantFiled: October 17, 1986Date of Patent: February 9, 1988Assignee: Ovonic Synthetic Materials Company, Inc.Inventors: Stanford R. Ovshinsky, Hellmut Fritzsche, Julius J. Harwood, Alan M. Kadin, John E. Keem
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Patent number: 4715904Abstract: In production of a permanent magnet by forming a roll of an elongated magnetic metal strap, a strap made from a spinodal decomposition type magnetic alloy is subjected, at least before formation into a roll, to age-hardening under concurrent magnetization in order to obtain a magnet having significant radial magnetic anisotropy well suited for use in sound systems such as loudspeakers.Type: GrantFiled: February 24, 1984Date of Patent: December 29, 1987Assignee: Nippon Gakki Seizo Kabushiki KaishaInventors: Kenzaburo Iijima, Yoshinori Hayashi
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Patent number: 4715891Abstract: A method of forming a magnetic material. The magnetic material is a solid mass of grains, and has magnetic parameters characterized by : (1) a maximum magnetic energy product, (BH).sub.max, greater than 15 megagaussoersteds; and (2) a remanence greater than 9 kilogauss. The magnetic material is prepared by a two step solidification, heat treatment process. The solidification process is carried out by controlled vaporization of precursor elements of the alloy into an inert atmosphere, with subsequent controlled vapor phase condensation. This may be accomplished by vaporizing a precursor type alloy in a plasma torch, such as an argon torch, a hydrogen torch, or other electro-arc torch to form a particulate fine grain alloy. The resulting product of this alternative method is a particulate fine grain alloy. The solid particles have a morphology characterized as being one or more of (i) amorphous; (ii) microcrystalline; or (iii) polycrystalline.Type: GrantFiled: October 17, 1986Date of Patent: December 29, 1987Assignee: Ovonic Synthetic Materials Company, Inc.Inventors: Stanford R. Ovshinsky, Stephen J. Hudgens, David D. Allred, Gregory DeMaggio
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Patent number: 4684406Abstract: Permanent magnet materials of the Fe-B-R type are produced by:preparing a metallic powder having a mean particle size of 0.3-80 microns and a composition of 8-30 at % R, 2-28 at % B, and the balance Fe,compacting, andsintering, at a temperature of 900-1200 degrees C. Co up to 50 at % may be present. Additional elements M (Ti, Ni, Bi, V, Nb, Ta, Cr, Mo, W, Mn, Al, Sb, Ge, Sn, Zr, Hf) may be present. The process is applicable for anisotropic and isotropic magnet materials.Type: GrantFiled: June 30, 1986Date of Patent: August 4, 1987Assignee: Sumitomo Special Metals Co., Ltd.Inventors: Yutaka Matsuura, Masato Sagawa, Setsuo Fujimura
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Patent number: 4678634Abstract: Method of preparing an anisotropic permanent magnet by a powder metallurgical technique, in which, the step of orientation of anisotropically magnetic particles during shaping by compression to give a green body prior to sintering, the magnetic field is applied pulse-wise to the mass of magnetic particles and an impacting compressive force is applied to the thus oriented particles in the direction parallel to the magnetic field during the period in which a pulse of the pulse-wise magnetic field is sustained. This method ensures a much higher degree of particle orientation than in the conventional static-field method by virtue of the possibility of obtaining a much stronger magnetic field without problems which otherwise are unavoidable. The principle of the method is applicable to the preparation of a cylindrical or annular permanent magnet magnetizable in a plurality of radial directions.Type: GrantFiled: April 14, 1986Date of Patent: July 7, 1987Assignee: Shin-Etsu Chemical Co., Ltd.Inventors: Yoshio Tawara, Ken Ohashi
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Patent number: 4649248Abstract: An annealing furnace for annealing magnetic cores therein. Each magnetic core is placed on a tray on which the core is transferred on rollers through the furnace along with a conductive magnetizing conductor or shaft positioned inside the core and a current source for supplying a current to the conductive magnetizing shaft. After the tray, core and current source pass through the furnace, the annealed core is removed from the tray, and the tray and current source are returned to the furnace entrance for reuse with another core.Type: GrantFiled: June 4, 1985Date of Patent: March 10, 1987Assignee: Allied CorporationInventors: Hiroshi Yamaguchi, Teruaki Tanaka, Masatake Hirai, Tadashi Kohketsu, Masahiro Matsumoto, Kenji Kawate
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Patent number: 4628809Abstract: Apparatus and method for forming radial orientation rare earth-transition metal magnets in continuous arc rings by hot isostatic pressing. A method includes the steps of compacting rare earth-transition metal powders having a particle size up to 40 microns into radially oriented rings in a mold provided with a radially aligning field, stacking a plurality of compacted radially oriented rings within an annular cavity within a sealed, evacuated canister to form a cylinder of a predetermined height, subjecting the canister to temperatures in the range of 900.degree. to 1150.degree. C. under a gas pressure of 15 kpsi to densify the compacts, and cooling the canister and the compacts to room temperature.Type: GrantFiled: August 5, 1985Date of Patent: December 16, 1986Assignee: The Charles Stark Draper LaboratoryInventors: Dilip K. Das, Kaplesh Kumar, Ernest C. Wettstein
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Patent number: 4604147Abstract: An alloy is proposed for use in making permanent magnets. The alloy has the following composition by weight:______________________________________ Chromium 22.5 to 25.5% Cobalt 15.0 to 17.5% Molybdenum 2.0 to 4.0% Silicon 0.1 to 0.8% Oxygen less than 0.10% Effective carbon less than 0.06% Remainder iron and unavoidable impurities, ______________________________________where effective carbon is defined as carbon content plus 0.86 times nitrogen content.In a method of manufacturing permanent magnets, a workpiece is made of the alloy, for example by suction or extrusion casting, and the workpiece is subjected to a heat treatment comprising:(a) a homogenizing annealing for 15 minutes to 3 hours at 1230.degree. C. to 1280.degree. C., followed by quenching in water or oil; and(b) a thermo-magnetic treatment for 10 to 30 minutes at 720.degree. C. to 740.degree. C., followed by the application for 10 to 120 minutes in a preferred axial direction of a magnetic field of 80 to 240 kA/m at a temperature of 630.degree. C.Type: GrantFiled: September 17, 1984Date of Patent: August 5, 1986Assignee: Thyssen Edelstahlwerke AGInventors: Helmut Brandis, Wolfgang Spyra
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Patent number: 4564400Abstract: A method for producing magnets from powdered magnetic alloy, and magnets having improved remanence and good coercive force; the method comprises aligning a particle charge of magnet alloy within a container, which aligning may be achieved by use of a pulsating magnetic field; consolidating the charge after alignment to a density in excess of 95% of theoretical density by cold or hot isostatic pressing, or a combination thereof.Type: GrantFiled: March 8, 1984Date of Patent: January 14, 1986Assignee: Crucible Materials CorporationInventors: Kalatur S. V. L. Narasimhan, Charles D. Preusch
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Patent number: 4558077Abstract: Novel epoxy compositions and a method of using them to make bonded rare earth-iron alloy magnets have been developed. The epoxy resins are polyglycidyl ethers of polyphenol alkanes that have high glass transition temperatures. The epoxy resin is provided in the form of a powder containing a suitable amount of a latent imidazole curing agent. The powder is mixed with rare earth-iron alloy particles, the mixture is compacted, and the resultant compact is heated to melt the powder and activate the curing agent. The alloy particles in the resultant magnet body are exceptionally resistant to flux loss upon aging.Type: GrantFiled: March 8, 1984Date of Patent: December 10, 1985Assignee: General Motors CorporationInventor: Richard K. Gray
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Patent number: 4544421Abstract: A method of field annealing a thin-film electromagnetic read/write head formed of magnetic-field-responsive material having a known Curie temperature. Such a head also includes an electric coil for operatively exciting the head. The method includes the steps of heating the head to a temperature less than the Curie temperature, and then cooling the head while applying electric current to the coil sufficient to induce magnetic flux in the head. The foregoing steps, properly applied, align the magnetic-field-responsive structure, such as magnetic domains in a soft magnetic material, in the direction of operative flux flow in the head.Type: GrantFiled: October 11, 1983Date of Patent: October 1, 1985Assignee: Ferix CorporationInventor: Gilbert D. Springer
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Patent number: 4537850Abstract: A method and apparatus for rejuvenating magnetic toner used in certain electrostatic copying machines. The used toner is placed in a container which is inserted in an air coil which is energized to produce a magnetic field which remagnetizes the toner. The coil is provided by mounting a hollow non-magnetic tube in a case and winding this tube with wire. A timing circuit energized by a momentary switch determines the length of time a magnetic field is applied to the toner being recycled.Type: GrantFiled: August 30, 1983Date of Patent: August 27, 1985Inventor: Wilfred Smeiman
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Patent number: 4536233Abstract: A permanent magnet formed from a powdered alloy ingot of samarium (Sm) and cobalt (Co), copper (Cu), and iron (Fe) and at least one element selected from the group consisting of zirconium (Zr), titanium (Ti), hafnium (Hf), tantalum (Ta), niobium (Nb), and vanadium (V), formed predominantly of Sm.sub.2 Co.sub.17 crystals and having at least 50 volume percent columnar crystals in the macrostructure is provided. The alloy ingots having increased columnar crystals are prepared by melting the alloy composition at a temperature at least about 320.degree. C. above the melting point of the composition and casting the ingot at a casting speed faster than about 5.0 sec/kg of alloy.Type: GrantFiled: November 30, 1983Date of Patent: August 20, 1985Assignee: Kabushiki Kaisha Suwa SeikoshaInventors: Itaru Okonogi, Tatsuya Shimoda
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Patent number: 4533407Abstract: Apparatus and method for forming radial orientation rare earth-transition metal magnets in continuous arc rings by hot isostatic pressing. A method includes the steps of compacting rare earth-transition metal powders having a particle size up to 40 microns into radially oriented rings in a mold provided with a radially aligning field, stacking a plurality of compacted radially oriented rings within an annular cavity within a sealed, evacuated cannister to form a cylinder of a predetermined height, subjecting the cannister to temperatures in the range of 900.degree. to 1150.degree. C. under a gas pressure of 15 kpsi to densify the compacts, and cooling the cannister and the compacts to room temperature.Type: GrantFiled: March 30, 1981Date of Patent: August 6, 1985Assignee: The Charles Stark Draper Laboratory, Inc.Inventors: Dilip K. Das, Kaplesh Kumar, Ernest C. Wettstein
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Patent number: 4533408Abstract: A method of preparing alloy of a transition metal and lanthanide comprising the steps of alloying a transition metal, boron, at least one lower-weight lanthanide having none or few stable compounds with iron, optionally one or more higher-weight lanthanides, a glass former, and optionally the pseudo lanthanide, yttrium; forming an amorphous or nearly amorphous metastable microstructure in the alloy; and heating the amorphous alloy to form a polycrystalline, multiphase, fine-grain single-domain structure.Type: GrantFiled: September 6, 1983Date of Patent: August 6, 1985Inventor: Norman C. Koon
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Patent number: 4515880Abstract: Method of developing latent magnetic images obtained by reflex thermomagnetic recording. A reflex imaging member is magnetized and a latent magnetic image formed thereon by thermoremanent exposure. The imaging member is developed by contacting it with magnetizable toner particles which have been subjected to a high intensity magnetizing field such that the toner particles retain a residual internal magnetic field after removal of the magnetizing field.Type: GrantFiled: September 24, 1980Date of Patent: May 7, 1985Assignee: Xerox CorporationInventor: Stephen L. Gaudioso
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Patent number: 4497672Abstract: The permanet magnet composed of a rare earth element, e.g. samarium, and cobalt together with iron, copper and some other additive elements and prepared according to the inventive method has a high coercive force and excellent squareness of the magnetic hysteresis loop despite the relatively low content of copper which has been considered to be indispensable for obtaining a high coercive force. The characteristic feature of the inventive method consists in the aging treatment of the sintered body of the alloy powder of a specified composition undertaken in two or more steps, each being carried out by continuously cooling the sintered body within a specified temperature range at a specified cooling velocity.Type: GrantFiled: April 4, 1983Date of Patent: February 5, 1985Assignee: Shin-Etsu Chemical Co., Ltd.Inventors: Yoshio Tawara, Ken Ohashi
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Patent number: 4459248Abstract: A temperature sensitive element comprises fine grain powders which consist of a spin reorientation type ferromagnetic material having a transition temperature range, below which transition temperature range the easy direction of magnetization of the spin reorientation type ferromagnetic material is predetermined in one crystallographic direction thereof and above which transition temperature range the easy direction of magnetization is a predetermined other direction perpendicular to the predetermined one crystallographic direction. The temperature sensitive element is produced by compacting the fine grain powders at a temperature higher than the transition temperature range. According to the present invention, it is possible to use a polycrystalline rare earth cobalt alloy material in the field where low Curie point ferrite has been used or where bimetals have been used for a thermal valve or a temperature controlling device.Type: GrantFiled: March 5, 1982Date of Patent: July 10, 1984Assignee: Fujitsu LimitedInventors: Masato Sagawa, Wataru Yamagishi
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Patent number: 4437908Abstract: A method of treating a preshaped magnetic material wherein a mechanical vibration and/or a high-energy beam are applied to the material held in a magnetic field.Type: GrantFiled: October 10, 1980Date of Patent: March 20, 1984Assignee: Inoue-Japax Research IncorporatedInventor: Kiyoshi Inoue
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Patent number: RE31317Abstract: Permanent magnetic alloys comprising 11.5-12.5% rare earth components of which 6.3-12% is samarium and 0.5-6.2% is yttrium; 0.2-2.5% hafnium, .[.19.5-26.5%.]. .Iadd.10.5-26.5% .Iaddend.iron, 7-10.5% copper, and 52-70.7% cobalt, the ranges of the components being in atomic ratios. The alloys are prepared by obtaining 1-50 .mu.m. powders of the components, compacting the powder after mangetic field orientation sintering the compacted powders at 1160.degree.-1220.degree. for 1-10 hours, cooling the sintered body at a rate of at least 1.degree. C./second until the temperature is about 900.degree. C., and then annealing the body at 750.degree.-900.degree. C.Type: GrantFiled: November 24, 1980Date of Patent: July 19, 1983Assignee: Namiki Precision Jewel Co., Ltd.Inventors: Nobuo Imaizumi, Kazuo Wakana