Treatment In A Magnetic Field Patents (Class 148/103)
  • Patent number: 7314530
    Abstract: A press machine 10 includes a die 12 with a through hole 12a that defines a cavity, a first press surface 14a and a second press surface 16a for pressing a magnetic powder 18 loaded in the cavity, and magnetic field generating means for applying an aligning magnetic field to the magnetic powder 18 in the cavity. At least one of the first and second press surfaces 14a and 16a has a region made of a material having a Vickers hardness that is higher than 200 but equal to or lower than 450. In pressing the powder under the aligning magnetic field, the press machine 10 minimizes the disturbance in the orientation of the powder.
    Type: Grant
    Filed: October 1, 2002
    Date of Patent: January 1, 2008
    Assignee: Neomax Co., Ltd.
    Inventors: Tsutomu Harada, Takashi Tajiri, Shuichi Okuyama
  • Patent number: 7302867
    Abstract: A magnetic transducer element is formed by rotating an integral region of a shaft about an axis in the presence of a magnetic source. An annulus of magnetization results in having its magnetization in the axial direction. The exterior magnetic field emanated by the annulus exhibits respective axial magnetic profiles of its axially and radially directed components which have an axial shift under torque. The direction of profile shift depends on the rotational direction of the shaft while magnetization proceeds. A pair of regions exhibiting opposite shift directions provide signals in which torque-dependent shift is separated from axial displacements of the shaft. An annulus of magnetization may be non-uniform with angle about the shaft axis. Measures to prevent eddy currents generated in the rotting region of the shaft under magnetization are disclosed as we “sweet spots” for sensor placement to mitigate non-uniformity effects.
    Type: Grant
    Filed: September 24, 2004
    Date of Patent: December 4, 2007
    Assignee: Abas, Inc.
    Inventor: Lutz Axel May
  • Patent number: 7255752
    Abstract: A method for manufacturing an R-T-B system rare earth permanent magnet that is a sintered body comprising a main phase consisting of an R2T14B phase (wherein R represents one or more rare earth elements (providing that the rare earth elements include Y), and T represents one or more transition metal elements essentially containing Fe, or Fe and Co), and a grain boundary phase containing a higher amount of R than the above main phase, wherein a product that is rich in Zr exists in the above R2T14B phase, the above manufacturing method comprising the steps of: preparing an R-T-B alloy containing as a main component the R2T14B phase and also containing Zr, and an R-T alloy containing R and T as main components, wherein the amount of R is higher than that of the above R-T-B alloy; obtaining a mixture of the R-T-B alloy powder and the R-T alloy powder; preparing a compacted body with a certain form from the above mixture; and sintering the above compacted body, wherein, in the above sintering step, the above produ
    Type: Grant
    Filed: March 11, 2004
    Date of Patent: August 14, 2007
    Assignee: TDK Corporation
    Inventors: Chikara Ishizaka, Gouichi Nishizawa, Tetsuya Hidaka, Akira Fukuno, Nobuya Uchida
  • Patent number: 7255751
    Abstract: When an R-T-B system rare earth permanent magnet is obtained by a mixing method to obtain a sintered body with a composition consisting essentially of 25% to 35% by weight of R (wherein R represents one or more rare earth elements, providing that the rare earth elements include Y), 0.5% to 4.5% by weight of B, 0.02% to 0.6% by weight of Al and/or Cu, 0.03% to 0.25% by weight of Zr, 4% or less by weight (excluding 0) of Co, and the balance substantially being Fe, wherein a coefficient of variation (CV) showing the dispersion of Zr is 130 or lower, Zr is contained in a low R alloy. This sintered body enables to inhibit the grain growth, while keeping the decrease of magnetic properties to a minimum, and to improve the suitable sintering temperature range.
    Type: Grant
    Filed: September 29, 2003
    Date of Patent: August 14, 2007
    Assignee: TDK Corporation
    Inventors: Gouichi Nishizawa, Chikara Ishizaka, Tetsuya Hidaka, Akira Fukuno
  • Patent number: 7244318
    Abstract: A blended powder including a first powder containing an R2T14B phase as a main phase, and a second powder containing an R2T17 phase at 25 wt % or more of the whole is prepared. Herein, R is at least one element selected from the group consisting of all rare-earth elements and Y (yttrium), T is at least one element selected from the group consisting of all transition elements, and Q is at least one element selected from the group consisting of B (boron) and C (carbon). The blended powder is sintered, so as to manufacture a permanent magnet having a structure in which a rare-earth element included in the second powder is concentrated in a grain surgace region of a main phase.
    Type: Grant
    Filed: January 22, 2002
    Date of Patent: July 17, 2007
    Assignee: Neomax Co., Ltd.
    Inventors: Takao Sekino, Yuji Kaneko
  • Patent number: 7232495
    Abstract: The method of the present invention includes a step of preparing a rare earth magnet 22 disposed for forming a cylinder 22a, a first magnetizing step of applying a first external magnetic field H1 to the rare earth magnet 22, thereby forming a first region R1 magnetized from an inner side to an outer side of the cylinder 22a and a second region R2 magnetized from the outer side to the inner side, and a second magnetizing step of applying a second external magnetic field H2 so that an external magnetic field component forming an angle of more than 0° and less than 50° with a direction of the external magnetic field component applied in the first magnetizing step to a boundary between the first region R1 and the second region R2.
    Type: Grant
    Filed: July 29, 2002
    Date of Patent: June 19, 2007
    Assignee: Neomax Co., Ltd.
    Inventors: Eiji Sakaguchi, Hitoshi Morimoto
  • Patent number: 7211157
    Abstract: A rare-earth alloy ingot is produced by melting an alloy composed of 20–30 wt % of a rare-earth constituent which is Sm alone or at least 50 wt % Sm in combination with at least one other rare-earth element, 10–45 wt % of Fe, 1–10 wt % of Cu and 0.5–5 wt % of Zr, with the balance being Co, and quenching the molten alloy in a strip casting process. The strip-cast alloy ingot has a content of 1–200 ?m size equiaxed crystal grains of at least 20 vol % and a thickness of 0.05–3 mm. Rare-earth sintered magnets made from such alloys exhibit excellent magnetic properties and can be manufactured under a broad optimal temperature range during sintering and solution treatment.
    Type: Grant
    Filed: June 10, 2004
    Date of Patent: May 1, 2007
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Kazuaki Sakaki, Koji Sato, Takahiro Hashimoto, Hajime Nakamura, Takehisa Minowa
  • Patent number: 7207102
    Abstract: Methods are provided for forming a plurality of permanent magnets with two different north-south magnetic pole alignments for use in microelectromechanical (MEM) devices. These methods are based on initially magnetizing the permanent magnets all in the same direction, and then utilizing a combination of heating and a magnetic field to switch the polarity of a portion of the permanent magnets while not switching the remaining permanent magnets. The permanent magnets, in some instances, can all have the same rare-earth composition (e.g. NdFeB) or can be formed of two different rare-earth materials (e.g. NdFeB and SmCo). The methods can be used to form a plurality of permanent magnets side-by-side on or within a substrate with an alternating polarity, or to form a two-dimensional array of permanent magnets in which the polarity of every other row of the array is alternated.
    Type: Grant
    Filed: April 1, 2004
    Date of Patent: April 24, 2007
    Assignee: Sandia Corporation
    Inventors: Alexander W. Roesler, Todd R. Christenson
  • Patent number: 7204891
    Abstract: Rare earth magnet scrap and/or sludge is remelted for reuse. Once a rare earth-free magnet-constituent metal feed is loaded in a melting furnace and heated into a melt, a rare earth-containing metal feed and the rare earth magnet scrap and/or sludge are added to the melt, a particulate flux of an alkali metal, alkaline earth metal or rare earth metal halide and having an average particle size of 1–50 ?m, preferably wrapped in a metal foil, is added to the melt, and the resulting mixture is melted, from which an alloy ingot is obtained. The valuable elements in the scrap and/or sludge can be recycled. Better separation between the slag and the molten metal ensures that the ingot is obtained from the melt in a high yield.
    Type: Grant
    Filed: August 31, 2005
    Date of Patent: April 17, 2007
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Koichi Hirota, Takehisa Minowa
  • Patent number: 7201809
    Abstract: A radially anisotropic ring magnet endowed with good magnetic characteristics and having throughout the magnet an angle of 80 to 100° between a center axis thereof and a radial anisotropy imparting direction is manufactured by a pressing operation.
    Type: Grant
    Filed: August 27, 2003
    Date of Patent: April 10, 2007
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Koji Sato, Mitsuo Kawabata, Takehisa Minowa
  • Patent number: 7166171
    Abstract: Disclosed is a longitudinal magnetic field compacting method and device for manufacturing a neodymium (Nd) based rare earth magnet in the shape of a butterfly for use in VCM of HDD or DVD, a disk or coin for use in coreless motors, and a block for use in linear motors, characterized in that a longitudinal compacting process is performed under a pulse magnetic field for orientation of rare earth powders in the direction of an applied magnetic field. Further, a compacted body of the rare earth powders has the same shape as end products, thus no additional processing cost, thereby lowering manufacturing costs. In addition, the rare earth powders can be subjected to an aligning process and a longitudinal compacting process at the same time under the high pulse magnetic field of 50–70 kOe, whereby the resulting rare earth magnet can have excellent magnetic properties of 42–50 MGOe.
    Type: Grant
    Filed: July 16, 2003
    Date of Patent: January 23, 2007
    Assignee: Jahwa Electronics Co., Ltd.
    Inventor: Dong-Hwan Kim
  • Patent number: 7063752
    Abstract: A method for refining the grain size of alloys which undergo ferromagnetic to paramagnetic phase transformation and an alloy produced therefrom. By subjecting the alloy to a timed application of a strong magnetic field, the temperature of phase boundaries can be shifted enabling phase transformations at lower temperatures.
    Type: Grant
    Filed: December 9, 2002
    Date of Patent: June 20, 2006
    Assignee: ExxonMobil Research and Engineering Co.
    Inventors: Jayoung Koo, Shiun Ling, Michael John Luton, Hans Thomann, Narasimha-Rao Venkata Bangaru
  • Patent number: 7056393
    Abstract: A method of making a sintered body for a rare earth magnet includes the steps of (a) preparing a first coarse powder by coarsely pulverizing a rare earth alloy sintered body by a hydrogen pulverization process, (b) preparing a first fine powder by finely pulverizing the first coarse powder, (c) preparing a second fine powder by pulverizing an alloy block of a rare earth alloy material, and (d) sintering a mixed powder including the first and second fine powders. The first and second fine powders each includes a main phase represented by (LR1-xHRx)2T14A, where T is Fe and/or at least one non-Fe transition metal element; A is boron and/or carbon; LR is at least one light rare earth element; HR is at least one heavy rare earth element; and 0?x<1.
    Type: Grant
    Filed: May 28, 2002
    Date of Patent: June 6, 2006
    Assignee: Neomax, Co., Ltd.
    Inventors: Koki Tokuhara, Hitoshi Morimoto
  • Patent number: 7037465
    Abstract: A powder compacting method includes the steps of: providing a powder material; loading the powder material into a cavity; uniaxially pressing the powder material, which has been loaded into the cavity, between two opposed press surfaces, thereby obtaining a compact, wherein at least one of the two press surfaces is deformed elastically under a compacting pressure when contacting with the powder material in the cavity; and unloading the compact from the cavity. According to this powder compacting method, even when the powder material has a non-uniform fill density distribution, a compact with a uniform density distribution can be obtained at a high productivity.
    Type: Grant
    Filed: November 5, 2001
    Date of Patent: May 2, 2006
    Assignee: Neomax Co., Ltd.
    Inventor: Atsushi Ogawa
  • Patent number: 7014811
    Abstract: A method for producing rare earth sintered magnets includes the steps of pressing and compacting an alloy powder for the rare earth sintered magnets, thereby preparing a plurality of green compacts, arranging the green compacts on a receiving plane in a direction in which a projection area of each of the green compacts onto the receiving plane is not maximized, and heating the green compacts, thereby sintering the green compacts and obtaining a plurality of sintered bodies.
    Type: Grant
    Filed: June 25, 2002
    Date of Patent: March 21, 2006
    Assignee: Neomax Co., Ltd.
    Inventors: Daisuke Harimoto, Yuji Kaneko, Akira Nakamura
  • Patent number: 7004228
    Abstract: To make a raw alloy, consisting mostly of amorphous structure, highly productively and at a reduced cost for a nanocomposite magnet, a molten alloy represented by Fe100-x-y-zRxQyMz (where R is at least one element selected from Pr, Nd, Dy and Tb; Q is B and/or C; M is at least one element selected from Co, Al, Si, Ti, V, Cr, Mn, Ni, Cu, Ga, Zr, Nb, Mo, Ag, Pt, Au and Pb; and 1 at %?x<6 at %, 15 at %?y?30 at % and 0 at %?z?7 at %) is prepared. This molten alloy is rapidly cooled by a strip casting process in which the alloy is fed onto a chill roller, rotating at a peripheral velocity of 3 m/s to less than 20 m/s, at a feeding rate per unit contact width of 0.2 kg/min/cm to 5.2 kg/min/cm. In this manner, an alloy including at least 60 volume percent of amorphous phase can be obtained.
    Type: Grant
    Filed: September 25, 2001
    Date of Patent: February 28, 2006
    Assignees: Santoku Corporation, Neomax Co., Ltd.
    Inventors: Ryo Murakami, Hirokazu Kanekiyo, Satoshi Hirosawa
  • Patent number: 6991686
    Abstract: To provide a method for producing a magnetostrictive material of excellent magnetostrictive characteristics. The method for producing a magnetostrictive material, wherein a mixture composed of Starting Materials A, B and C is sintered, where A is represented by Formula 1 (TbxDy1-x)Ty (T is at least one metallic element selected from the group consisting of Fe, Ni and Co, 0.35<x?0.50 and 1.70?y?2.00), B is represented by Formula 2 DytT1-t (0.37?t?1.00), and C contains T, to produce a magnetostrictive material represented by Formula 3 (TbvDy1-v)Tw (0.27?v<0.50, and 1.70?w?2.00), wherein oxygen content is set at 500 to 3,000 ppm for Starting Material A and at 2,000 to 7,000 ppm for Starting Material B.
    Type: Grant
    Filed: January 25, 2005
    Date of Patent: January 31, 2006
    Assignee: TDK Corporation
    Inventors: Seigo Tokoro, Teruo Mori
  • Patent number: 6984270
    Abstract: A radial anisotropic sintered magnet formed into a cylindrical shape includes a portion oriented in directions tilted at an angle of 30° or more from radial directions, the portion being contained in the magnet at a volume ratio in a range of 2% or more and 50% or less, and a portion oriented in radial directions or in directions tilted at an angle less than 30° from radial directions, the portion being the rest of the total volume of the magnet. The radial anisotropic sintered magnet has excellent magnet characteristics without occurrence of cracks in the steps of sintering and cooling for aging, even if the magnet has a shape of a small ratio between an inner diameter and an outer diameter.
    Type: Grant
    Filed: October 31, 2002
    Date of Patent: January 10, 2006
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Koji Sato, Mitsuo Kawabata, Takehisa Minowa
  • Patent number: 6984271
    Abstract: A rare earth magnet to be used in a motor. The rare earth magnet comprises rare earth magnet particles. Additionally, a rare earth oxide is present among the rare earth magnet particles, the rare earth oxide being represented by the following general formula (I): R2xR?2(1?x)O3??(I) where each of R and R? is one element selected from the group consisting of yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu), and 0<x<1.
    Type: Grant
    Filed: March 26, 2004
    Date of Patent: January 10, 2006
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Tetsurou Tayu, Takae Ono, legal representative, Makoto Kano, Munekatsu Shimada, Yoshio Kawashita, Takeshi Yamauchi, Hideaki Ono, deceased
  • Patent number: 6982010
    Abstract: The present invention relates to a high performance rare earth-iron giant magnetostrictive material of the formula (Tbx1Dyx2Smx3Hox4Rx5)(Sy1Py2Fe1-y1-y2-y3Ty3)Q obtained by using an industry grade pure iron, instead of physically pure iron such as electrolyzed pure iron or hydrogen reduced pure iron, as iron source. The invention relates also to a method of preparing the giant magnetostrictive material.
    Type: Grant
    Filed: October 31, 2002
    Date of Patent: January 3, 2006
    Assignee: Materitek Co. Ltd.
    Inventor: Zheng Liu
  • Patent number: 6863742
    Abstract: A bulk anisotropic rare earth permanent magnet consists essentially of R, Fe or Fe and Co, and N, wherein R is selected from rare earth elements inclusive of Y and contains Sm as a main component, and has a primary phase of Th2Zn17 type rhombohedral crystal structure, a density of at least 90% of the true density, and unidirectionally oriented C-axis. By electric conduction hot pressing of SmFeN base powder under rapid heating and rapid cooling conditions, the powder can be worked into the anisotropic bulk magnet without decomposing the 2-17 phase.
    Type: Grant
    Filed: March 14, 2002
    Date of Patent: March 8, 2005
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventor: Ken Ohashi
  • Patent number: 6764607
    Abstract: A powder for forming a R—Fe—B bonded magnet, wherein an R compound, such as an R oxide, an R carbide, an R nitride or an R hydride, which is contained in a raw material powder such as a super rapidly cooled powder or a hydrogen treated powder (HDDR powder) and reacts with water vapor to change into R(OH)3, has been converted to a R hydroxide R(OH)3 being stable in the air by subjecting the raw material powder to a heat treatment in an atmosphere of a pressured water vapor. The powder for forming an R—Fe—B bonded magnet is free from the generation of a white powder in the surface of or inside a bonded magnet formed from the powder and accordingly, is free from the occurrence or cracking, chipping, swelling or the like in the bonded magnet caused by volume expansion of a white powder.
    Type: Grant
    Filed: April 2, 2002
    Date of Patent: July 20, 2004
    Assignee: Sumitomo Special Metals Co., Ltd.
    Inventor: Takashi Ikegami
  • Patent number: 6746545
    Abstract: An R—Fe—B permanent magnet wherein R is Nd or a combination of Nd with a rare earth element is prepared by casting an R—Fe—B alloy, crushing the alloy in an oxygen-free atmosphere of argon, nitrogen or vacuum, effecting comminution, compaction, sintering, aging, and cutting and/or polishing the magnet to give a finished surface. The magnet is then heat treated in an argon, nitrogen or low-pressure vacuum atmosphere having a limited oxygen partial pressure, obtaining a highly oil resistant sintered permanent magnet having corrosion resistance and hydrogen barrier property even in a high pressure hot environment of refrigerant and/or lubricant as encountered in compressors.
    Type: Grant
    Filed: May 30, 2001
    Date of Patent: June 8, 2004
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Kazuo Tamura, Masanobu Shimao, Ryuji Hamada, Takehisa Minowa
  • Patent number: 6741440
    Abstract: A magnetization method and apparatus is described as utilizing a pair of mechanically counter-vibrated permanent magnets having mutually facing unlike magnetic poles, and wherein a ferromagnetic article, or article containing ferromagnetic elements in close-set array, is placed for subjection to pulsed magnetizing flux between the pair of counter-vibrated magnets. Uses of the invention include making magnets and modifying the current drain property of a multi-plate nickel-metal hydride battery.
    Type: Grant
    Filed: February 27, 2001
    Date of Patent: May 25, 2004
    Inventor: Robert Neville O'Brien
  • Patent number: 6669788
    Abstract: A Fe—B—R type permanent magnetic, consisting of: 13-19 atomic % R, where R consists essentially of a mixture of rare earth elements Nd and/or Pr, and Ce, where Ce is between 0.2 and 5.0 wt. % of R; 4-20 atomic % B, and the balance comprising Fe. In a preferred aspect, R comprises 15-16 atomic % B; of which Ce is approximately 0.5% and the remaining rare earths Pr and Nd are in a ratio of 3:1. A process of producing a Fe—B—R permanent magnet as described above, and a Fe—B—R magnetic material made by such process.
    Type: Grant
    Filed: May 21, 2001
    Date of Patent: December 30, 2003
    Assignees: General Electric Company, Batou Iron and Steel (Group) Co. LTD
    Inventors: Chen Pei Xin, Wang Biao, Ni De Zhen, Mark Gilbert Benz, Juliana C. Shei
  • Patent number: 6653548
    Abstract: A cuboid p-type and an n-type thermoelectric conversion material having a composite of an alloy powder for a rare earth magnet and a bismuth-based thermoelectric conversion material that has been rendered a p-type semiconductor or an n-type semiconductor by the addition of the required dopant, are arranged alternately with a material with low thermal conductivity and high electrical resistivity interposed between them. The low- and the high-temperature sides of these thermoelectric conversion materials are connected with wires, a magnetic field is applied in the x axis direction, a temperature gradient ∇T is imparted in the z axis direction a p-n junction is created, and thermoelectromotive force is extracted from the connection end in a plane in the y axis direction. There is a marked increase in the Seebeck coefficient even though no magnetic field is applied externally.
    Type: Grant
    Filed: October 10, 2001
    Date of Patent: November 25, 2003
    Assignee: Sumitomo Special Metals Co., Ltd.
    Inventor: Osamu Yamashita
  • Patent number: 6602352
    Abstract: A method and apparatus for manufacturing a rare earth magnet is disclosed. In a first step, a compact is produced by compacting rare earth alloy powder in a predetermined space in an orienting magnetic field. Next, a demagnetizing process is performed for the compact, and the compact is ejected from the predetermined space. Then, a additional demagnetizing process is performed for magnetic powder adhering to a surface of the compact by applying an magnetic field to the compact after the compact is ejected.
    Type: Grant
    Filed: June 27, 2001
    Date of Patent: August 5, 2003
    Assignee: Sumitomo Special Metals Co., Ltd.
    Inventors: Shuhei Okumura, Akira Nakamura
  • Patent number: 6594124
    Abstract: An improved stabilization scheme for a GMR read head is described. Two important changes relative to prior art designs have been introduced. Instead of biasing by means of a permanent magnet or through exchange coupling with an antiferromagnetic layer, the magnetostatic field emanating from a nearby, but not contiguous, layer is used. Additionally, to obtain optimum stability with this scheme the bias, instead of running parallel to the easy axis of the free layer, is canted away from it towards the direction of the demagnetizing field of the pinned layer. A process for the manufacture of the structure is also described.
    Type: Grant
    Filed: November 6, 2001
    Date of Patent: July 15, 2003
    Assignee: Headway Technologies, Inc.
    Inventors: You Feng Zheng, Kochan Ju, Simon Liao
  • Patent number: 6589366
    Abstract: Method of making an active magnetic refrigerant represented by Gd5(SixGe1−x)4 alloy for 0≦x≦1.0 comprising placing amounts of the commercially pure Gd, Si, and Ge charge components in a crucible, heating the charge contents under subambient pressure to a melting temperature of the alloy for a time sufficient to homogenize the alloy and oxidize carbon with oxygen present in the Gd charge component to reduce carbon, rapidly solidifying the alloy in the crucible, and heat treating the solidified alloy at a temperature below the melting temperature for a time effective to homogenize a microstructure of the solidified material, and then cooling sufficiently fast to prevent the eutectoid decomposition and improve magnetocaloric and/or the magnetostrictive and/or the magnetoresistive properties thereof.
    Type: Grant
    Filed: February 23, 2001
    Date of Patent: July 8, 2003
    Assignee: Iowa State University Research Foundation, Inc.
    Inventors: Karl A. Gschneidner, Jr., Alexandra O. Pecharsky, Vitalij K. Pecharsky
  • Publication number: 20020153061
    Abstract: A method for producing a compact of rare earth alloy powder of the present invention includes: a powder-filling step of filling rare earth allow powder in a cavity formed by inserting a lower punch into a through hall of a die of a powder compacting machine; and a compression step of pressing the rare earth alloy powder while applying a magnetic field, the steps being repeated a plurality of times. When the (n+1)th (n is an integer equal to or more than 1) stage compression step is to be carried out, the top surface of a compact produced in the n-th stage compression step is placed at a position above the bottom surface of a magnetic portion of a die.
    Type: Application
    Filed: June 11, 2002
    Publication date: October 24, 2002
    Applicant: SUMITOMO SPECIAL METALS CO., LTD.
    Inventors: Tsutomu Harada, Hitoshi Morimoto, Atsuo Tanaka
  • Publication number: 20020129872
    Abstract: A bulk anisotropic rare earth permanent magnet consists essentially of R, Fe or Fe and Co, and N, wherein R is selected from rare earth elements inclusive of Y and contains Sm as a main component, and has a primary phase of Th2Zn17 type rhombohedral crystal structure, a density of at least 90% of the true density, and unidirectionally oriented C-axis. By electric conduction hot pressing of SmFeN base powder under rapid heating and rapid cooling conditions, the powder can be worked into the anisotropic bulk magnet without decomposing the 2-17 phase.
    Type: Application
    Filed: March 14, 2002
    Publication date: September 19, 2002
    Inventor: Ken Ohashi
  • Patent number: 6375759
    Abstract: A new class of processes for fabrication of precision miniature rare earth permanent magnets is disclosed. Such magnets typically have sizes in the range 0.1 to 10 millimeters, and dimensional tolerances as small as one micron. Very large magnetic fields can be produced by such magnets, lending to their potential application in MEMS and related electromechanical applications, and in miniature millimeter-wave vacuum tubes. This abstract contains simplifications, and is supplied only for purposes of searching, not to limit or alter the scope or meaning of any claims herein.
    Type: Grant
    Filed: November 30, 1999
    Date of Patent: April 23, 2002
    Assignee: Sandia Corporation
    Inventors: Todd R. Christenson, Terry J. Garino, Eugene L. Venturini
  • Patent number: 6368551
    Abstract: The method for preparation of sintered permanent magnets according to the present invention comprises the steps of: mixing fully fine powder of a crystalline mother alloy for permanent magnet containing a rare-earth element, Fe and B as the essential components with fine powder of zinc oxide, compaction molding the resulted mixture in the presence of a magnetic field, sintering the compacted mixture in vacuum to cause generation of oxygen and metallic zinc by thermal decomposition of the zinc oxide; segregation of a part of metallic component in the mother alloy at the boundary and inside of the mother alloy crystal; formation of amorphous metallic oxide by forced oxidation of the segregated metal with the generated oxygen; crystallization of the amorphous metallic oxide; formation of an epitaxial junction between the crystallized metallic oxide and the mother alloy crystal; and evaporation of the metallic zinc into the vacuum, and quenching the sintered compact.
    Type: Grant
    Filed: August 16, 2000
    Date of Patent: April 9, 2002
    Assignee: Sanei Kasei Co., Ltd.
    Inventors: Shigenobu Sekine, Yuko Kawasaki, Yoshiki Kuwabara, Hiroji Sato, Minoru Narita, Kazushi Suzuki, Koichi Tono, Keiji Okada, Kenji Sakaguchi, Mitsuhisa Hirata
  • Publication number: 20020036031
    Abstract: A sintered rare earth magnet consisting essentially of 20-30% by weight of R (wherein R is Sm or a mixture of Sm and another rare earth element), 10-45% by weight of Fe, 1-10% by weight of Cu, 0.5-5% by weight of Zr, and the balance of Co has on its surface a composite layer containing Sm2O3 and/or CoFe2O4 in Co or Co and Fe. The magnet is resistant to hydrogen embrittlement.
    Type: Application
    Filed: July 30, 2001
    Publication date: March 28, 2002
    Applicant: Shin-Etsu Chemical Co., Ltd.
    Inventors: Kazuaki Sakaki, Masanobu Shimao, Hajime Nakamura, Takehisa Minowa
  • Patent number: 6361738
    Abstract: The method of producing an R—Fe—B magnet of the present invention is characterized in that R—Fe—B alloy fine powder is molded in a magnetic field and sintered using a lubricant for molding magnets containing specific components, individually or as a mixture, of specific amounts of methyl caproate and/or methyl caprylate, which provide high crystal orientation, and lubricant comprising depolymerized polymer for improving molded article strength, or a lubricant for molding magnets wherein Ti coupling agent that improves crystal orientation is added to this lubricant for molding magnets. Each particle of the fine powder has a high degree of crystal orientation in the direction of the magnetic field, and molded article strength is markedly improved, leading to improved mass-productivity and yield. Moreover, the above-mentioned lubricants do not react with this magnet powder during sintering and are emitted as a gas.
    Type: Grant
    Filed: March 28, 2000
    Date of Patent: March 26, 2002
    Assignee: Sumitomo Special Metals Co., Ltd.
    Inventors: Yuji Kaneko, Junichiro Baba, Kazuo Tanaka, Shizuo Mori
  • Publication number: 20020029823
    Abstract: A method of preparing a magnetostrictive material, including the steps of:
    Type: Application
    Filed: December 21, 2000
    Publication date: March 14, 2002
    Inventors: Hideki Minagawa, Takeshi Okutani, Hideaki Nagai, Takashi Tsurue, Yoshinori Nakata, Keiji Kamada
  • Patent number: 6214288
    Abstract: An improvement is proposed in the powder metallurgical method for the preparation of a rare earth-based permanent magnet comprising the steps of compression-molding a magnet alloy powder into a powder compact and sintering the powder compact into a sintered magnet body. The improvement, which has an effect of increasing the density of the sintered body and consequently increased magnetic properties of the magnet product, comprises conducting the sintering heat treatment in two steps consisting of a first partial sintering treatment in vacuum or under a subatmospheric pressure of an inert gas immediately followed by a second partial sintering treatment under a normal to superatmospheric pressure of, for example, up to 20 atmospheres.
    Type: Grant
    Filed: December 8, 1999
    Date of Patent: April 10, 2001
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Matou Kusunoki, Takehisa Minowa
  • Patent number: 6187259
    Abstract: The object of the present invention is to provide rare-earth system sintered magnets such as R—Fe—B system or R—Co system having excellent magnetic properties, unique configuration of a small size, thin wall thickness and intricate geometry. With the method for preparing the present invention, a granulation of alloy powders can be achieved easily, a chemical reaction between rare-earth system and binder substances can be suppressed, so that the residual oxygen and carbon levels in the sintered products can be reduced. Moreover, by this production method, the flowability and lubricant capability during the forming process can be improved. The dimension accuracy and productivity are also enhanced. A certain type of binder is added to rare-earth alloy powders and kneaded into a slurry state. The slurry is then formed into granulated powders by spray-dryer equipment. The thus granulated powders are molded, and sintered through a powder metallurgy technique.
    Type: Grant
    Filed: March 19, 1997
    Date of Patent: February 13, 2001
    Assignee: Sumitomo Special Metals Co., Ltd.
    Inventors: Osamu Yamashita, Yoshihisa Kishimoto, Wataru Takahashi, Nobushige Hiraishi, Yoshiyuki Hashimasa, Masakazu Ohkita
  • Patent number: 6162364
    Abstract: A method and system for diamagnetic manipulation of an object in a surrounding medium in a low gravity environment is provided. The system can be used in various applications such as containerless materials processing, protein crystal growth, and particulate filtering. If the application requires directional manipulation of the object, at least one magnet or electromagnet is required. The object is repulsed by the magnet if the object is more strongly diamagnetic than the surrounding medium. If the object is less diamagnetic than the surrounding medium, however, then the object is effectively attracted to the magnet. For an application that requires suspension of the object, two oppositely polarized magnets are used to generate an appropriate magnetic field gradient to suspend the object in a location where opposing field vectors generated by the two magnets cancel each other out, producing a net field strength of zero.
    Type: Grant
    Filed: June 16, 1998
    Date of Patent: December 19, 2000
    Assignee: The Boeing Company
    Inventors: Brian J. Tillotson, Larry P. Torre, Janice D. Houston
  • Patent number: 6159308
    Abstract: A method of producing an R--Fe--B-based, sintered permanent magnet, wherein R is at least one rare earth element including Y, having a small oxygen content. A coarse alloy powder prepared by a reductive diffusion method is milled and recovered into a solvent to form a slurry. The slurry is wet-compacted to form a green body which is then sintered after removing the solvent. The milling, recovering, wet-compacting, solvent-removing and sintering steps are carried out while preventing the powder, slurry and green body from being brought into contact with air to minimize the oxygen content in the final sintered permanent magnet. The sintered permanent magnet produced has a high density and a high magnetic properties due to a low oxygen content.
    Type: Grant
    Filed: December 11, 1998
    Date of Patent: December 12, 2000
    Assignee: Hitachi Metals, Ltd.
    Inventors: Kimio Uchida, Masahiro Takahashi
  • Patent number: 6149861
    Abstract: It is an object of the present invention to provide a method for manufacturing a raw material alloy powder that can be utilized effectively in the regeneration of surplus or defective R--Fe--B type sintered magnets while leaving the main phase crystal grains alone, and a method for manufacturing an R--Fe--B type magnet. Surplus or defective R--Fe--B type sintered magnets are pulverized, acid washed, and dried, after which this product is subjected to a calcium reduction treatment and washed to remove the calcium component, which allows a raw material alloy powder composed of an Nd.sub.2 Fe.sub.14 B main phase system, which contributes the most to magnet characteristics, to be regenerated efficiently. An alloy powder for compositional adjustment that improves sintering and adjusts the composition is added to this main phase system raw material alloy powder to produce a sintered magnet, which facilitates the manufacture of a sintered magnet with superior magnet characteristics.
    Type: Grant
    Filed: April 6, 2000
    Date of Patent: November 21, 2000
    Assignee: Sumitomo Special Metals Co., Ltd.
    Inventors: Yuji Kaneko, Yasuhide Sasakawa, Katsuya Kase, Takashi Hashikawa, Kaname Takeya
  • Patent number: 6123781
    Abstract: A method of controlling magnetic characteristics of a spin valve effect MR element and a method of controlling magnetic characteristics of a magnetic head with the MR element include a step of supplying direct current with a gradually increasing value to the MR element so as to generate magnetic field in a desired direction and to generate joule heat, the generated magnetic field and the generated joule heat being applied to the MR element, and a step of controlling a magnetization direction caused by exchange coupling in the MR element based upon the applied magnetic field and the applied joule heat.
    Type: Grant
    Filed: February 23, 1998
    Date of Patent: September 26, 2000
    Assignee: TDK Corporation
    Inventor: Kouji Shimazawa
  • Patent number: 6120620
    Abstract: A permanent magnet having substantially stable magnetic properties is disclosed having as the active magnetic component a sintered product of compacted particulate iron-boron-rare earth intermetallic material, said sintered product having pores which are substantially non-interconnecting, a density of at least 87 percent of theoretical and a composition consisting essentially of in atomic percent about 13 to about 19 percent rare earth elements, about 4 to about 20 percent boron and about 61 to about 83 percent of iron with or without impurities; where the rare earth content is greater than 50 percent praseodymium with an effective amount of a light rare earth selected from the group consisting of cerium, lanthanum, yttrium and mixtures thereof, and balance neodymium.
    Type: Grant
    Filed: February 12, 1999
    Date of Patent: September 19, 2000
    Assignee: General Electric Company
    Inventors: Mark Gilbert Benz, Juliana Ching Shei
  • Patent number: 6112042
    Abstract: A developing roller is made up of a magnet member and a sleeve surrounding the magnet member. A sophisticated magnetic characteristic including a repulsive pole can be easily formed on the surface of the sleeve. The repulsive pole causes a developer to be sharply released from the surface of the sleeve. A developing device including the developing roller is also disclosed.
    Type: Grant
    Filed: November 3, 1999
    Date of Patent: August 29, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Tsuyoshi Imamura, Makoto Nakamura, Kyota Koetuka, Kenji Narita, Kenichi Ishiguro
  • Patent number: 6080352
    Abstract: A brushless permanent-magnet direct current motor has a permanent magnet which is magnetized to create an offset angle between detent and mutual torques for providing sufficient starting torque for all relative orientations between the stator and the rotor of the motor. This is accomplished by providing a permanent magnet in which the global magnetization of the magnet has been disrupted by the application of a local magnetic field to a portion of the magnet, thereby to provide a magnetic anomaly in the global magnetization. Also, a method of magnetization of the magnet is described.
    Type: Grant
    Filed: March 31, 1997
    Date of Patent: June 27, 2000
    Assignee: Seagate Technologies, Inc.
    Inventors: John C. Dunfield, Gunter K. Heine, Marcel Jufer, Kamran Oveyssi
  • Patent number: 6080245
    Abstract: A rare earth permanent magnet consisting essentially, by weight, of 27.0-31.0 % of at least one rare earth element including Y, 0.5-2.0 % of B, 0.02-0.15 % of N, 0.25 % or less of O, 0.15 % or less of C, at least one optional element selected from the group consisting of 0.1-2.0 % of Nb, 0.02-2.0 % of Al, 0.3-5.0 % of Co, 0.01-0.5 % of Ga and 0.01-1.0 % of Cu, and a balance of Fe, and a production method thereof. The contents of rare earth element, oxygen, carbon and oxygen in the magnet are regulated within the specific ranges.
    Type: Grant
    Filed: October 2, 1998
    Date of Patent: June 27, 2000
    Assignee: Hitachi Metals, Ltd.
    Inventors: Kimio Uchida, Masahiro Takahashi, Fumitake Taniguchi
  • Patent number: 6001193
    Abstract: A method of producing a hard magnetic alloy compact at low cost, in which an alloy that contains not less than 50% by weight of an amorphous phase and exhibits hard magnetism in a crystallized state is solidified and molded at around its crystallization temperature under applied pressure by utilizing the softening phenomenon occurring during a crystallization process. The resulting compact has high hard magnetic characteristics and can be applied as permanent magnet members such as in motors, actuators, and speakers.
    Type: Grant
    Filed: March 25, 1997
    Date of Patent: December 14, 1999
    Assignees: Alps Electric Co., Ltd., Akihisa Inoue, Tsuyoshi Masumoto
    Inventors: Akinori Kojima, Takao Mizushima, Akihiro Makino, Akihisa Inoue, Tsuyoshi Masumoto
  • Patent number: 5997804
    Abstract: A rare earth permanent magnet consisting essentially, by weight, of 27.0-31.0% of at least one rare earth element including Y, 0.5-2.0% of B, 0.02-0.15% of N, 0.25% or less of O, 0.15% or less of C, at least one optional element selected from the group consisting of 0.1-2.0% of Nb, 0.02-2.0% of Al, 0.3-5.0% of Co, 0.01-0.5% of Ga and 0.01-1.0% of Cu, and a balance of Fe, and a production method thereof. The contents of rare earth element, oxygen, carbon and oxygen in the magnet are regulated within the specific ranges.
    Type: Grant
    Filed: May 21, 1997
    Date of Patent: December 7, 1999
    Assignee: Hitachi Metals Ltd.
    Inventors: Kimio Uchida, Masahiro Takahashi, Fumitake Taniguchi
  • Patent number: 5976271
    Abstract: Provided by the invention is a method for the preparation of a magnetically anisotropic permanent magnet mainly consisting of crystallites of the Nd.sub.2 Fe.sub.14 B phase. The method comprises the steps of:(a) preparing an amorphous alloy of neodymium, iron and boron in molar fractions corresponding to the Nd.sub.2 Fe.sub.14 B phase or a nanocomposite of the Nd.sub.2 Fe.sub.14 B/Fe.sub.3 B or Nd.sub.2 Fe.sub.14 B/Fe system, for example, by the melt-spun method; and (b) subjecting the amorphous alloy of neodymium, iron and boron to a heat treatment in a magnetic field of at least 3 T (tesla) at a temperature in the range from 550 to 800.degree. C. for a length of time in the range from 1.times.10.sup.2 to 1.times.10.sup.4 seconds in an atmosphere of a non-reactive gas or vacuum.
    Type: Grant
    Filed: April 6, 1998
    Date of Patent: November 2, 1999
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Tadao Nomura, Masaru Ito, Ken Ohashi
  • Patent number: 5841348
    Abstract: A resonator for use in a marker, with a bias element which produces a bias field, in a magnetomechanical electronic article surveillance system is composed of an amorphous magnetostrictive alloy containing iron, cobalt, nickel, silicon and boron in quantities for giving the resonator a quality Q which is between about 100 and 600. The amorphous magnetostrictive alloy is annealed in a transverse magnetic field for giving it a B-H loop which is linear up to about 8 Oe and an anisotropy field strength of at least 10 Oe. When the resonator is excited to resonate by a signal emitted by the transmitter in the surveillance system, it produces a signal at a mechanical resonant frequency which can be detected by the receiver of the detection system. Due to the resonator having a quality Q in the above range, the signal produced by the resonator in a first detector window, beginning approximately 0.
    Type: Grant
    Filed: July 9, 1997
    Date of Patent: November 24, 1998
    Assignee: Vacuumschmelze GmbH
    Inventor: Giselher Herzer