Heat Treatment Patents (Class 148/121)
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Patent number: 6302972Abstract: An inventive material alloy for a nanocomposite magnet is represented by a general formula Fe100−x−yRxBy, Fe100−x−y−zRxByCoz, Fe100−x−y−uRxByMu or Fe100−x−y−z−uRxByCozMu. R is a rare-earth element. 90 atomic percent or more of R is Pr and/or Nd, while equal to or larger than 0 atomic percent and less than 10 atomic percent of R is another lanthanoid and/or Y. M is at least one element selected from the group consisting of Al, Si, Ti, V, Cr, Mn, Ni, Cu, Ga, Zr, Nb, Mo, Hf, Ta, W, Pt, Pb, Au and Ag. The molar fractions x, y, z and u meet the inequalities of 2≦x≦6, 16≦y≦20, 0.2≦z≦7 and 0.01≦u≦7, respectively. The alloy includes a metastable phase Z represented by at least one of a plurality of Bragg reflection peaks observable by X-ray diffraction analysis. The at least one peak corresponds to a lattice spacing of 0.179 nm±0.005 nm.Type: GrantFiled: December 6, 1999Date of Patent: October 16, 2001Assignee: Sumitomo Special Metals Co., LTDInventors: Satoshi Hirosawa, Hirokazu Kanekiyo, Yasutaka Shigemoto
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Patent number: 6302970Abstract: A manufacturing method of a thin-film magnetic head with a spin valve effect MR read sensor includes a temperature-annealing step of firmly fixing the direction of the pinned magnetization in the spin valve effect MR sensor. The temperature-annealing step is executed by a plurality of times.Type: GrantFiled: December 18, 1998Date of Patent: October 16, 2001Assignee: TDK CorporationInventors: Koji Shimazawa, Manabu Ohta, Tetsuro Sasaki
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Patent number: 6255005Abstract: Provided is a composite magnetic member made of a single material combining a ferromagnetic portion and a non-magnetic portion in which the ferromagnetic portion has better soft magnetism than conventional members and the non-magnetic portion has the same stable characteristic as conventional members. A method of producing the ferromagnetic portion of the member and a method of forming the non-magnetic portion are also provided. The composite magnetic member is made of an Fe—Cr—C-base alloy steel containing 0.1 to 5.0 weight % Al and has a ferromagnetic portion with a maximum magnetic permeability of not less than 400 and a non-magnetic portion with a magnetic permeability of not more than 2. In this member the number of carbides with a grain size of not less than 0.1 &mgr;m is regulated to not more than 50 in an area of 100 &mgr;m2 and the proportion of the number of carbides with a grain size of not less than 1.0 &mgr;m to the number of all carbides is controlled to not less than 15%.Type: GrantFiled: July 22, 1999Date of Patent: July 3, 2001Assignee: Hitachi Metals, Ltd.Inventors: Shin-ichiro Yokoyama, Tsutomu Inui, Hideya Yamada
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Patent number: 6245441Abstract: This is a composite magnetic member excellent in corrosion resistance having a chemical composition consisting essentially, by weight, of 0.30 to 0.80% C, more than 16.0% but not more than 25.0% Cr, 0.1 to 4.0% Ni, 0.1 to 0.06% N, at least one kind not more than 2.0% in total selected from the group consisting of Si, Mn and Al, and the balance Fe and impurities, and having a ferromagnetic portion and a non-magnetic portion.Type: GrantFiled: June 18, 1999Date of Patent: June 12, 2001Assignees: Hitachi Metals, Ltd., Denso CorporationInventors: Shin-ichiro Yokoyama, Tsutomu Inui, Yoshihiro Tanimura
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Patent number: 6190463Abstract: A process for prooducing an Fe—Co based magnetic alloy having not only good magnetic properties but also excellent mechanical characteristics is provided which includes a first step of heating an Fe—Co based magnetic alloy material having a Co content which is in a range of 30% by weight≦Co≦65% by weight to convert the metallographic structure thereof into a &ggr; single-phase structure, a second step of gradually cooling the material to an a single-phase range at a cooling rate C1 set in a range of 20 K°/hr≦C1≦0.5 K°/sec, and a third step of subjecting the material to a magnetic softening treatment.Type: GrantFiled: December 1, 1998Date of Patent: February 20, 2001Assignee: Honda Giken Kogyo Kabushiki kaishaInventors: Hitoshi Itami, Nagatsugu Mukaibo, Tetsuya Kondo
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Patent number: 6190465Abstract: Soft magnetic alloy of the iron-nickel type, the chemical composition of which comprises, by weight: 40%≦Ni+Co≦65%; 0%≦Co≦7%; 2%≦Cr≦5%; 1%≦Ti≦3%; 0%≦Al≦0.5%; 0%≦Mn+Si≦2%; optionally, up to 3% Mo, 2% W, 2% V, 1.5% Nb, 1% Ta and 3% Cu, the sum of the Cr, Mo, W, V, Nb, Ta and Cu contents being less than 7% and the sum of the Mo, W, V, Nb, Ta and Cu contents being less than 4%; the balance being iron and impurities, such as carbon, sulfur and phosphorus, resulting from the smelting process, the chemical composition furthermore satisfying the relationships: Cr<5−0.015×(Ni+Co−52.5)2, if: Ni+Co≦52.5; Cr<5−0.040×(Ni+Co−52.5)2, if: Ni+Co≧52.5; the alloy having a saturation induction Bs of greater than 0.9 tesla, a coercive field of less than 10 A/m, an electrical resistivity p of greater than 60 &mgr;&OHgr;.cm and a hardness of greater than 200 HV. Process for manufacturing the alloy and uses.Type: GrantFiled: July 2, 1998Date of Patent: February 20, 2001Assignee: Imphy Ugine PrecisionInventors: Lucien Coutu, Laurent Chaput, Thierry Waeckerle
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Patent number: 6183568Abstract: A soft magnetic thin micro-crystalline film of FeaBbNc (at %) wherein B is at least one of Zr, Hf, Ti, Nb, Ta, V, Mo and W, and 0<b≦20 and 0<c≦22 except the range of b≦7.5 and c≦5, shows low coercivity Hc of 80-400 Am−1 (1-5 Oe) which is stable upon heating at elevated temperature for glass bonding. This film is produced by crystallizing an amorphous alloy film of the similar composition at 350-650° C. to a crystal grain size up to 30 nm to provide uniaxial anisotropy and increased magnetic permeability at higher frequency. It can also provide low magnetostriction around &lgr;s=0. Composite magnetic head is made using this thin film. Diffusion preventive SiO2 layer disposed between ferrite core and this thin film in the magnetic head prevents an interdiffusion layer and suppress beat in the output signal.Type: GrantFiled: January 6, 1994Date of Patent: February 6, 2001Assignee: Fuji Photo Film Co., Ltd.Inventors: Kanji Nakanishi, Osamu Shimizu, Satoshi Yoshida, Masaaki Katayama, Tatsuya Isomura
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Patent number: 6176943Abstract: A magnetostrictive wire element made of amorphous ferromagnetic material is tailored for installation within a sensor by treatment which includes annealment by heating while a stress condition is imposed thereon, and applying a DC electric current thereto during said annealment to produce a cylindrical magnetic field relative to the wire element establishing spiral magnetic anistropy during cooldown after said heating.Type: GrantFiled: January 28, 1999Date of Patent: January 23, 2001Assignee: The United States of America as represented by the Secretary of the NavyInventors: Marilyn Wun-Fogle, James B. Restorff, Arthur E. Clark
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Patent number: 6176944Abstract: The present invention provides a high purity cobalt sputter target having a single phase h.c.p. structure and a magnetic permeability less than the intrinsic magnetic permeability of the material. Substantially pure cobalt is cast and slowly cooled, such as at a rate of 15° C./min. Or less, to form a cast target of single phase h.c.p. crystallographic structure. This cast target is hot worked at a temperature of at least about 1000° C. to impart a strain of about 65% or greater into the cobalt material, followed by a slow, controlled cooling to room temperature, such as at a rate of 15° C./min. or less, to maintain the single phase h.c.p. crystallographic structure. The cooled target is then cold worked at substantially room temperature to impart a strain of about 5-20%. The sputter target of the present invention processed by this method has a magnetic permeability of less than about 9, grain sizes in the size range of about 70-160 &mgr;m, and average grain size of about 130 &mgr;m.Type: GrantFiled: November 1, 1999Date of Patent: January 23, 2001Assignee: Praxair S.T. Technology, Inc.Inventors: Alfred Snowman, Holger Koenigsmann, Andre Desert, Thomas J. Hunt
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Patent number: 6171410Abstract: A hard magnetic alloy in accordance with the present invention is composed of at least element T selected from the group consisting of Fe, Co and Ni, at least one rare earth element R, and boron (B). The hard magnetic alloy has an absolute value of the temperature coefficient of magnetization of 0.15%/° C. or less and a coercive force of 1 kOe, when being used in a shape causing a permeance factor of 2 or more. A hard magnetic alloy compact in accordance with the present invention has a texture, in which at least a part or all of the texture comprises an amorphous phase or fine crystalline phase having an average crystal grain size of 100 nm or less, is subjected to crystallization or grain growth under stress, such that a mixed phase composed of a soft magnetic or semi-hard magnetic phase and a hard magnetic phase is formed in the texture, and anisotropy is imparted to the crystal axis of the hard magnetic phase.Type: GrantFiled: February 20, 1998Date of Patent: January 9, 2001Assignee: Alps Electric Co. Ltd.Inventors: Akinori Kojima, Akihiro Makino, Takashi Hatanai, Yutaka Yamamoto, Akihisa Inoue
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Patent number: 6143094Abstract: A method of stress inducing transformation from the austenite phase to the martensite phase by conducting cold working on material of austenite stainless steel in the temperature range from the point Ms to the point Md. The above cold working is a biaxial tensing. An intermediately formed hollow body is made, which includes a ferromagnetic portion and a non-magnetic portion contracting inward. Then, the intermediately formed body is subjected to a stress removing process in which residual tensile stress is removed from an intermediately formed body. In the stress removing process, it is preferable that a punch is press-fitted into the intermediately formed body so as to expand a non-magnetic portion and then the intermediately formed body is drawn with ironing while the punch is inserted so that the residual tensile stress can be changed into the residual compressive stress in the non-magnetic portion.Type: GrantFiled: April 18, 1997Date of Patent: November 7, 2000Assignee: Denso CorporationInventors: Satoshi Sugiyama, Yoshihiro Tanimura, Masaki Shimizu, Yoshitada Katayama, Hidehito Kito, Suehisa Sugisaka
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Patent number: 6139648Abstract: Magnetostrictive material such as Terfenol-D undergoes annealing treatment y heating for a limited period of time to an elevated temperature below the melting point, followed by cooling to a preferred magnetic state in which a compressive stress generated and applied during treatment is retained in the treated material as a built-in prestress.Type: GrantFiled: February 19, 1999Date of Patent: October 31, 2000Assignee: The United States of America as represented by the Secretary of the NavyInventors: Marilyn Wun-Fogle, James B. Restorff, Arthur E. Clark
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Patent number: 6137412Abstract: A marker for employment in a magnetic merchandise monitoring system is composed of one or more oblong, ductile, magnetostrictive strips composed of amorphous ferromagnetic material. These strips experience a change in resonant frequency due to a change of a pre-magnetization field and are excited to longitudinal, mechanical resonant oscillation at the resonant frequency f.sub.r due to an alternating magnetic field, whereby the mechanical stresses resulting from the resonant oscillations cause a change in magnetization of the strips and, thus, a detectable change of the alternating magnetic field. The material of which the strips are composed exhibits a flat B-H loop that proceeds optimally linearly into the range of saturation; further, the strips exhibit a magnetic anisotropy transverse to the longitudinal strip direction, whereby the anisotropy field strength is greater than the pre-magnetization field strength.Type: GrantFiled: June 21, 1999Date of Patent: October 24, 2000Assignee: Vacuumschmelze GmbHInventor: Giselher Herzer
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Patent number: 6123781Abstract: 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: GrantFiled: February 23, 1998Date of Patent: September 26, 2000Assignee: TDK CorporationInventor: Kouji Shimazawa
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Patent number: 6123780Abstract: A method for manufacturing a spin valve GMR head is describe in which a fixed magnetic layer of the head may maintain magnetization in a desired orientation. In one aspect of the invention, the method comprises steps of: forming a magnetic film including at least a free magnetic layer, a non-magnetic metallic layer, a fixed magnetic layer, and a magnetic domain control layer; subjecting the magnetic film to a first heat treatment under a magnetic field to enhance magnetic anisotropy of the free magnetic layer; and subjecting the magnetic film to a second heat treatment under a magnetic field and at a higher temperature than the maximum temperature applied in the processes that precede the second heat treatment, to fix the magnetization in the fixed magnetic layer.Type: GrantFiled: January 14, 1998Date of Patent: September 26, 2000Assignee: Fujitsu LimitedInventors: Hitoshi Kanai, Kenichi Aoshima, Kenichiro Yamada, Mitsumasa Okada, Eiji Shimizu, Junichi Kane
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Patent number: 6120617Abstract: For manufacturing a pulse generator wherein a voltage pulse dependent on the change in magnetic field can be achieved by sudden magnetic reversal (Barkhausen skip) given an applied magnetic field, an iron alloy is employed for one of the materials of the composite member, the additional alloy constituents of this iron alloy being selected such that a structural conversion with volume change respectively occurs at different temperatures. For producing the stressed condition, a thermal treatment is then implemented, which includes heating above the upper transition temperature and a cooling below the lower transition temperature. As a result, substantially greater stresses between the materials of the composite member arise, causing a pulse behavior significantly improved in comparison to known pulse generators of the type capable of recognizing constant or alternating magnetic fields.Type: GrantFiled: April 7, 1994Date of Patent: September 19, 2000Assignee: Vacuumschmelze GmbHInventors: Gernot Hausch, Christian Radeloff, Gerd Rauscher
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Patent number: 6083325Abstract: A method for making a Fe-based soft magnetic alloy where an alloy melt is injected onto a moving cooling unit to form an amorphous alloy ribbon. The alloy melt contains Fe as a main component, B and at least one metallic element M selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo and W, the composition of the alloy melt being selected such that the resulting amorphous alloy ribbon is characterized by a first crystallization temperature at which fine grain bcc Fe crystallites precipitate, and a second crystallization temperature at which a compound phase containing Fe--B and/or Fe--M precipitates. The amorphous alloy ribbon is then annealed at a temperature which is higher that the first crystallization temperature and less than the second crystallization temperature for an annealing time in the range of 0 minutes to 20 minutes.Type: GrantFiled: July 11, 1997Date of Patent: July 4, 2000Assignee: Alps Electric Co., Ltd.Inventors: Teruo Bitoh, Yasuo Hayakawa, Takashi Hatanai, Akihiro Makino, Akihisa Inoue, Tsuyoshi Masumoto
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Patent number: 6057766Abstract: A magnetostrictive element for use in a magneto-mechanical marker has a resonant frequency characteristic that is at a minimum at a bias field level corresponding to the operating point of the magnetomechanical marker. The magnetostrictive element has a magnetomechanical coupling factor k in the range 0.28 to 0.4 at the operating point. The magnetostrictive element is formed by applying cross-field annealing to an iron-rich amorphous metal alloy ribbon (45 to 82 percent iron) which includes a total of from 2 to 17 percent of one or more of Mn, Mo, Nb, Cr, Hf, Zr, Ta, V. Cobalt, nickel, boron, silicon and/or carbon may also be included. The metal alloy may include one early transition element selected from the group consisting of Zr, Hf and Ta, and also a second early transition element selected from the group consisting of Mn, Mo, Nb, Cr, and V.Type: GrantFiled: October 2, 1998Date of Patent: May 2, 2000Assignee: Sensormatic Electronics CorporationInventors: Robert C. O'Handley, Wing K. Ho, Ming-Ren Lian, Nen-Chin Liu
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Patent number: 6053989Abstract: The present invention provides an amorphous or amorphous/microcrystalline metal alloy comprising Fe.sub.a Cr.sub.b V.sub.c P.sub.d Si.sub.e C.sub.f M.sub.g X.sub.h wherein M is selected from the group consisting of Cu, Ni, and mixtures thereof; X is selected from the group consisting of Mo, W, and mixtures thereof; a is about 66 to about 80; b is about 0.5 to about 5.0; c is about 0.5 to about 5.0; d is about 7.0 to about 13.0; e is about 0.2 to about 3.0; f is about 4.5 to about 8.0; g is about 0.1 to about 0.9; h is about 0.1 to about 3.0; and a, b, c, d, e, f, g, and h represent atomic percent where the total is nominally equal to 100 atomic percent. Such metal alloys have desirable magnetic properties such as high saturation induction, low coercivity and high normal permeability. Significantly cost-effective methods of producing such alloys using by-product ferrophosphorus from phosphorus production and impure sources of alloying elements are also provided.Type: GrantFiled: February 12, 1998Date of Patent: April 25, 2000Assignee: FMC CorporationInventors: Michael Orillion, Johan Pfeiffer, Yulig K. Kovneristy
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Patent number: 6007643Abstract: A magnetoresistive head in which an antiferromagnetic material having superior corrosion resistance is used is disclosed. In the magnetoresistive head, a pair of anti-ferromagnetic layers 24a and 24b are formed while contacting with a soft magnetic layer 23, and the antiferromagnetic layers 24a and 24b are made of a PdMn film.Type: GrantFiled: August 29, 1997Date of Patent: December 28, 1999Assignee: Fujitsu LimitedInventors: Hitoshi Kishi, Kazuo Kobayashi, Atsushi Tanaka, Yasuhiro Kitade, Yuko Miyake, Mitsuru Otagiri
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Patent number: 5976715Abstract: The invention is embodied in a soft magnetic thin film article comprising an iron--chromium-nitrogen (Fe--Cr--N) based alloy and methods for making such article. The soft magnetic thin film article is formed using an iron--chromium--nitrogen based alloy with tantalum in one embodiment and with at least one of the elements titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), molybdenum (Mo), niobium (Nb) or tungsten (W) in another embodiment. The article is formed such that the alloy has a relatively high saturation magnetization (e.g., greater than approximately 15 kG) and a relatively low coercivity (e.g., less than approximately 2.0 oersteds) in an as-deposited condition or, alternatively, with a very low temperature treatment (e.g., below approximately 150.degree. C.). The inventive films are suitable for use in electromagnetic devices, for example, in microtransformer cores, inductor cores and in magnetic read-write heads.Type: GrantFiled: November 6, 1997Date of Patent: November 2, 1999Assignee: Lucent Techologies Inc.Inventors: Li-Han Chen, Sungho Jin, Wei Zhu, Robert Bruce van Dover
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Patent number: 5976271Abstract: 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: GrantFiled: April 6, 1998Date of Patent: November 2, 1999Assignee: Shin-Etsu Chemical Co., Ltd.Inventors: Tadao Nomura, Masaru Ito, Ken Ohashi
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Patent number: 5935347Abstract: The present invention provides an Fe-base soft magnetic alloy and a laminated magnetic core formed by using the alloy which contains Fe as a main component and at least one element M and B selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo and W, in which at least 50% of the crystalline structure comprises fine crystalline grains having an average crystal grain size of 30 nm or less and a body-centered cubic structure, and the fracture strain at 300.degree. C. or less is 1. The ratios of the components Fe, and elements M and B are 75 to 93 atomic %, 4 to 9 atomic % and 0.5 to 18 atomic %, respectively. The alloy may contain other additive elements such as Cr, Ru, Hr, Ir, Si, Al, Ge, Ga and the like.Type: GrantFiled: November 29, 1996Date of Patent: August 10, 1999Assignee: Alps Electric Co., Ltd.Inventors: Kiyonori Suzuki, Akihiro Makino, Shoji Yoshida, Katsuaki Hangai, Tsuyoshi Masumoto, Akihisa Inoue
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Patent number: 5935722Abstract: A laminated composite structure of alternating metal powder layers, and layers formed of an inorganic bonding media powder, and a method for manufacturing same are discosed. The method includes the steps of assembling in a cavity alternating layers of a metal powder and an inorganic bonding media of a ceramic, glass, and glass-ceramic. Heat, with or without pressure, is applied to the alternating layers until the particles of the metal powder are sintered together and bonded into the laminated composite structure by the layers of sintered inorganic bonding media to form a strong composite structure. The method finds particular application in the manufacture of high performance magnets wherein the metal powder is a magnetic alloy powder.Type: GrantFiled: September 3, 1997Date of Patent: August 10, 1999Assignee: Lockheed Martin Energy Research CorporationInventors: Arthur J. Moorhead, Hyoun-Ee Kim
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Patent number: 5932032Abstract: A process by which solid magnet bodies can be efficiently produced from mrials with soft magnetic properties using the die casting process is disclosed. The process is characterized in that an alloy comprising the alloy constituents of the soft magnetic material in addition to one or more elements lowering the melting point is used as a starting material, and in that the additional elements are at least partially extracted from the magnet bodies that are produced from this alloy by the die casting method subsequently by a heat treatment in a reactive atmosphere. The process is applicable for the production of soft magnetic magnet bodies for relays, transformers, magnet valves, actuators, and other electromagnetic products.Type: GrantFiled: October 16, 1997Date of Patent: August 3, 1999Assignee: Institut fuer Festkoerper-und Werkstofforschung Dresden e.V.Inventor: Stefan Roth
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Patent number: 5922143Abstract: Process for manufacturing at least one magnetic core made of an iron-based soft magnetic alloy having a nanocrystalline structure, wherein an amorphous ribbon is manufactured from the magnetic alloy, the annealing temperature Tm which, in the case of the ribbon, leads to maximum magnetic permeability, is determined, at least one core blank is manufactured from the ribbon and at least one core blank is subjected to at least one annealing operation, said annealing being carried out at a temperature T of between Tm+10.degree. C. and Tm+50.degree. C. for a temperature hold time t of between 0.1 and 10 hours so as to cause nanocrystals to form.Type: GrantFiled: October 27, 1997Date of Patent: July 13, 1999Assignee: MecagisInventors: Philippe Verin, Georges Couderchon
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Patent number: 5916459Abstract: A method is disclosed for equalizing the electrical resistance of two or more magnetoresistor sensor elements positioned on a permanent magnet in a sensor assembly. The method may utilize a laser to reduce the magnetic field of the portion of the permanent magnet underlying the sensor with the higher electrical resistance.Type: GrantFiled: August 28, 1997Date of Patent: June 29, 1999Assignee: General Motors CorporationInventors: Thaddeus Schroeder, Thomas Arthur Perry, Martin Stephen Meyer, Bruno Patrice Bernard Lequesne
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Patent number: 5911840Abstract: Process for manufacturing a magnetic component made of an iron-based soft magnetic alloy having a nanocrystalline structure, the chemical composition of which is, in at. %, Fe.gtoreq.60%, 0.1%.ltoreq.Cu.ltoreq.3%, 0%.ltoreq.B.ltoreq.25%, 0%.ltoreq.Si.ltoreq.30%, and at least one element selected from niobium, tungsten, tantalum, zirconium, hafnium, titanium and molybdenum with contents of between 0.1% and 30%, the balance being impurities resulting from the smelting, the composition furthermore satisfying the relationship 5%.ltoreq.Si+B.ltoreq.30%, according to which an amorphous ribbon is manufactured from the magnetic alloy, a blank for a magnetic component is manufactured from the ribbon and the magnetic component is subjected to a crystallization heat treatment comprising at least one annealing step at a temperature of between 500.degree. C. and 600.degree. C. for a temperature hold time of between 0.Type: GrantFiled: December 11, 1997Date of Patent: June 15, 1999Assignee: MecagisInventors: Georges Couderchon, Philippe Verin
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Patent number: 5882436Abstract: The inventive material exhibits giant magnetoresistance upon application of an external magnetic field at room temperature. The hysteresis is minimal. The inventive material has a magnetic phase formed by eutectic decomposition. The bulk material comprises a plurality of regions characterized by a) the presence of magnetic lamellae wherein the lamellae are separated by a distance smaller than the mean free path of the conduction electrons, and b) a matrix composition having nonmagnetic properties that is interposed between the lamellae within the regions. The inventive, rapidly quenched, eutectic alloys form microstructure lamellae having antiparallel antiferromagnetic coupling and give rise to GMR properties. The inventive materials made according to the inventive process yielded commercially acceptable quantities and timeframes. Annealing destroyed the microstructure lamellae and the GMR effect. Noneutectic alloys did not exhibit the antiparallel microstructure lamellae and did not possess GMR properties.Type: GrantFiled: November 25, 1997Date of Patent: March 16, 1999Assignee: The Regents of the University of CaliforniaInventors: Johannes J. Bernardi, Gareth Thomas, Andreas R. Huetten
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Patent number: 5841212Abstract: Disclosed is a permanent magnetic field type rotating machine. The rotor core is made of a single chemical composition material comprising ferromagnetic and nonmagnetic zones. The nonmagnetic zones consists of a remolten and solidified metal structure and of a merely heated and cooled metal structure, and are present at portions of the rotor core where leakage flux is produced.Type: GrantFiled: April 8, 1997Date of Patent: November 24, 1998Assignee: Hitachi Metals, Ltd.Inventors: Masahiro Mita, Takashi Sasaki
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Patent number: 5837068Abstract: A bulk magnetoresistance effect material of a composition represented by the general formula: T.sub.100-A M.sub.A (wherein T is at least one element selected between Cu and Au; M is at least one element selected from the group consisting of Co, Fe, and Ni; and A is in the range: 1.ltoreq.A.ltoreq.50 by atomic percent) is prepared by casting a molten mixture of the above composition, and subjecting the resulting casting to homogenization and further to heat treatment. The bulk magnetoresistance effect material is high in the rate of change in the electrical resistance thereof, i.e., shows a large magnetoresistive effect and can be obtained in such bulk form in arbitrary shapes adaptable for various uses. Using the material, various types of magnetoresistive elements are obtained.Type: GrantFiled: January 6, 1997Date of Patent: November 17, 1998Assignee: Kazuaki Fukamichi and YKK CorporationInventors: Kazuaki Fukamichi, Noriyuki Kataoka, Yutaka Shimada, Hideki Takeda
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Patent number: 5821000Abstract: A composite magnetic member formed of a single material having a ferromagnetic section with high soft magnetism and a non-magnetic or the like section with sufficiently low magnetic (feebly magnetized or non-magnetic) and sufficient low MS temperature and a process for producing the member are provided. A composite magnetic member made of a single material of martensitic stainless steel including Ni having two sections of a ferromagnetic section having maximum permeability not less than 200 and coercive force not more than 2000 A/m and a feebly magnetized section having permeability not more than 2 and MS temperature not more than -30.degree. C.Type: GrantFiled: December 6, 1996Date of Patent: October 13, 1998Assignee: Hitachi Metals, Ltd. and Denso CorporationInventors: Tsutomu Inui, Jun Sunakawa, Masaki Shimizu, Keizo Takeuchi, Shinya Sugiura
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Patent number: 5803992Abstract: A method of making a permanent magnet wherein 1) a melt is formed having a base alloy composition comprising RE, Fe and/or Co, and B (where RE is one or more rare earth elements) and 2) TR (where TR is a transition metal selected from at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Al) and at least one of C and N are provided in the base alloy composition melt in substantially stoichiometric amounts to form a thermodynamically stable compound (e.g. TR carbide, nitride or carbonitride). The melt is rapidly solidified in a manner to form particulates having a substantially amorphous (metallic glass) structure and a dispersion of primary TRC, TRN and/or TRC/N precipitates. The amorphous particulates are heated above the crystallization temperature of the base alloy composition to nucleate and grow a hard magnetic phase to an optimum grain size and to form secondary TRC, TRN and/or TRC/N precipitates dispersed at grain boundaries.Type: GrantFiled: November 29, 1995Date of Patent: September 8, 1998Assignee: Iowa State University Research Foundation, Inc.Inventors: R. William McCallum, Daniel J. Branagan
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Patent number: 5801630Abstract: A harmonic-type EAS marker includes a wire segment formed of cobalt alloy. To form the wire segment, the cobalt alloy is cast as an amorphous wire, die-drawn to a smaller diameter, and then annealed with application of longitudinal tension. The annealed wire is cut to produce wire segments which have a magnetic hysteresis loop with a large Barkhausen discontinuity at a lower threshold level than has previously been achieved.Type: GrantFiled: November 8, 1996Date of Patent: September 1, 1998Assignee: Sensormatic Electronics CorporationInventors: Wing K. Ho, Jiro Yamasaki
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Patent number: 5786762Abstract: A magnetostrictive element for use in a magnetomechanical article surveillance marker formed by first annealing an amorphous metal alloy, such alloy comprising iron and cobalt with the proportion of cobalt being in the range of about 5 to about 45 atomic percent, in the presence of a saturating magnetic field and then second annealing the alloy in the absence of the saturating magnetic field.Type: GrantFiled: October 22, 1996Date of Patent: July 28, 1998Assignee: Sensormatic Electronics CorporationInventor: Nen-Chin Liu
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Patent number: 5783145Abstract: An iron-nickel alloy, the chemical composition of which includes by weight:30%.ltoreq.Ni+Co.ltoreq.85%;0%.ltoreq.Co+Cu+Mn.ltoreq.10%;0%.ltoreq.Mo+W+Cr.ltoreq.4%;0%.ltoreq.V+Si.ltoreq.2%;0%.ltoreq.Nb+Ta.ltoreq.1%;0.003%.ltoreq.C.ltoreq.0.05% 0.003%.ltoreq.Ti.ltoreq.0.15%;0.003%.ltoreq.Ti+Zr+Hf.ltoreq.0.15%;0.001%<S+Se+Te<0.015%;and the remainder, iron and impurities resulting from production; in addition, the chemical composition satisfies the relationship:0.ltoreq.Nb+Ta+Ti+Al.ltoreq.1%.A cold-rolled strip with a cubic texture and its uses.Type: GrantFiled: February 27, 1997Date of Patent: July 21, 1998Assignee: Imphy S.A.Inventors: Lucien Coutu, Pierre Louis Reydet
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Patent number: 5769965Abstract: A method for treating soft magnetic parts by annealing and producing a wear guard layer, in which the soft magnetic parts are either successively annealed and provided with a wear guard layer in a reaction chamber of a treatment apparatus, or the annealing and production of a wear guard layer are done simultaneously in the reaction chamber. This avoids intermediate transportation and temporary storage as well as contamination of the parts and reduces the costs of the method. The method is especially suitable for treating soft magnetic parts of electromagnetic fuel injection valves.Type: GrantFiled: April 19, 1996Date of Patent: June 23, 1998Assignee: Robert Bosch GmbHInventors: Dieter Liedtke, Juergen Graner, Norbert Keim, Joerg Illing
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Patent number: 5716460Abstract: Methods for preparing magnetic strips are provided in which the strips are manufactured to a thickness of less than about 0.005 inches and are made of a iron-based alloy having a manganese content of from about 8 to about 18 weight percent. The thin strips can be prepared by annealing the alloy, then cold rolling the alloy to reduce its thickness by at least about 40% to produce an initial strip, thermally treating the initial strip between about 400.degree. C. and its austenitizing temperature, cold rolling the initial strip to reduce its thickness by at least 75% to below about 0.005 inches, and thermally treating this strip at a temperature of at least 525.degree. C. for a period of time between about 0.1 and about 3 minutes. The strips are particularly useful in electronic article surveillance systems.Type: GrantFiled: May 8, 1996Date of Patent: February 10, 1998Assignee: The Arnold Engineering CompanyInventors: Neil R. Manning, Richard L. Anderson
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Patent number: 5685921Abstract: A process for preparing a duplex ferromagnetic alloy article is disclosed. The process includes the step of providing an elongated intermediate form of a ferromagnetic alloy having a substantially fully martensitic structure. The martensitic intermediate form undergoes an aging heat treatment under conditions of temperature and time that are selected to cause controlled precipitation of austenite in the martensitic alloy. The aged article is then cold-worked to a final cross-sectional dimension, preferably in a single reduction step, to provide an anisotropic structure and a coercivity, H.sub.c, of at least 30 Oe.Type: GrantFiled: January 31, 1996Date of Patent: November 11, 1997Assignee: CRS Holdings, Inc.Inventor: Bradford A. Dulmaine
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Patent number: 5684459Abstract: A longitudinal curvature in an amorphous metal alloy ribbon is reduced by heat-treatment. While the heat-treatment occurs, the alloy ribbon is bent "backwards" against the longitudinal curvature, to reduce the amount of heat-treatment required. The process is carried out continuously by transporting the alloy ribbon from reel to reel, while wrapping the ribbon around a heated roller. Using a discrete strip cut from the alloy ribbon subjected to the curvature-reducing process, a magnetomechanical EAS marker is constructed that has a relatively low profile, while retaining desired magnetic properties.Type: GrantFiled: October 2, 1995Date of Patent: November 4, 1997Assignee: Sensormatic Electronics CorporationInventors: Nen-chin Liu, Larry Speciale
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Patent number: 5676767Abstract: A magnetostrictive element for use in a magnetomechanical electronic article surveillance marker is formed by annealing a continuous ribbon of an amorphous metal alloy. The alloy ribbon is transported from reel to reel through an oven in which a transverse saturating magnetic field is applied to the ribbon. The annealed ribbon is cut into discrete strips which are suitable for use as magnetostrictive elements.Type: GrantFiled: April 12, 1995Date of Patent: October 14, 1997Assignee: Sensormatic Electronics CorporationInventors: Nen-Chin Liu, Larry Speciale
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Patent number: 5676768Abstract: A ring-type magnetic head is of a structure in which a metallic magnetic film is sandwiched between two substrates, and the metallic magnetic film has a saturation magnetic field not less than 50 A/m in all directions parallel to a film plane thereof. Where the metallic magnetic film is a Co-containing magnetically soft film having a crystallization temperature Tx greater than the Curie temperature Tc, the metallic magnetic film is subjected to a first heat treatment at a temperature not less than Tc and a second heat treatment at a temperature Ta of Tc-180.degree. C..ltoreq.Ta.ltoreq.Tc-30.degree. C. in the absence of any applied magnetic field. Where the metallic magnetic film is a Co-containing magnetically soft film having a crystallization temperature Tx less than the Curie temperature Tc, the metallic magnetic film is subjected to a first heat treatment at a temperature not greater than Tx while a rotating magnetic field is being applied thereto and a second heat treatment at a temperature Ta of Tx-200.Type: GrantFiled: October 3, 1994Date of Patent: October 14, 1997Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Shunsaku Muraoka, Akinaga Natsui, Yasuhiro Nakatani
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Patent number: 5676771Abstract: A non-oriented silicon steel sheet having a low core loss contains Si in an amount of about 2.5-5.0 wt % and S restricted to about 0.003 wt % or less and inclusions; the volume ratio of those inclusions having a particle size of about 4 .mu.m or higher to the total volume of inclusions is about 5-60%, and the volume ratio of inclusions having a particle size less than about 1 .mu.m to the total volume of inclusions is about 1-15%; when the sheet contains Mn in an amount of about 0.4-1.5%, and the volume ratio of particles less than 1 .mu.m is about 1-5%, the silicon steel sheet also has a low rotation core loss.The method of manufacturing comprises controlling the change of a cooling speed to about 5.degree. C./s.sup.2 or less in the cooling process of such steel sheet in a finish annealing.Type: GrantFiled: September 5, 1996Date of Patent: October 14, 1997Assignee: Kawasaki Steel CorporationInventors: Koji Yano, Atsuhito Honda, Takashi Obara, Minoru Takashima
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Patent number: 5675886Abstract: A torque sensor including a magnetostrictive alloy ribbon having plural rows of plural hole groups arranged longitudinally in the direction at a required angle to the shaft, and the magnetostrictive alloy ribbon is glued to the surface of the shaft, and means for detecting magnetic change are arranged around the magnetostrictive alloy ribbon in order to detect torque.Type: GrantFiled: September 5, 1996Date of Patent: October 14, 1997Assignee: Matsushita Electric Industrial Co. Ltd.Inventors: Hiroyuki Hase, Rihito Shoji
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Patent number: 5611871Abstract: A method for producing a nanocrystalline alloy wherein an amorphous alloy is heat-treated by keeping the temperature at a first heat treatment temperature higher than the crystallization temperature of the amorphous alloy for 0 to less than 5 minutes, and is cooled to room temperature at a cooling rate of 20.degree. C./min or more at least until the temperature falls to 400.degree. C. The amorphous alloy subjected to the first heat treatment may be further heat-treated at a second heat treatment temperature not higher than 500.degree. C. and lower than the first heat treatment temperature while applying a magnetic field. The nanocrystalline alloy produced by the method of the invention has a extremely high specific initial permeability as compared with the conventional nanocrystalline alloy, and is suitable for use in magnetic core of transformers, choke coils, etc.Type: GrantFiled: July 19, 1995Date of Patent: March 18, 1997Assignee: Hitachi Metals, Ltd.Inventors: Yoshihito Yoshizawa, Yoshio Bizen, Shin Nakajima, Shunsuke Arakawa
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Patent number: 5547520Abstract: The present invention provides a method for manufacturing a wear resistant igh permeability alloy consisting by weight of 60-90% Ni, 0.5-14% Nb, 0.0003-0.3% N and O in total (excluding 0% of N or O), and a remainder of Fe. The alloy has more than 3000 of effective permeability at 1 KHz, more than 4000 G of a saturated flux density and a recrystallization texture of {110}<112>+{311}<112>.Type: GrantFiled: January 31, 1995Date of Patent: August 20, 1996Assignee: The Foundation: The Research Institute of Electric and Magnetic AlloysInventors: Yuetsu Murakami, Katashi Masumoto
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Patent number: 5538565Abstract: A rare earth iron permanent magnet including at least one rare earth element, iron and boron as primary ingredients. The magnet can have an average grain diameter of less than or equal to about 150 .mu.m and a carbon content of less than or equal to about 400 ppm and an oxygen content of less than or equal to about 1000 ppm. The permanent magnet is prepared by casting a molten alloy. In one embodiment, the cast body is heat treated at a temperature of greater than or equal to about 250.degree. C. Alternatively, the material can be cast and hot worked at a temperature of greater than or equal to about 500.degree. C. Finally, the material can be cast, hot worked at a temperature of greater than or equal to about 500.degree. C. and then heat treated at a temperature of greater than or equal to about 250.degree. C. The magnets provided in accordance with the invention are relatively inexpensive to produce an have excellent performance characteristics.Type: GrantFiled: June 24, 1993Date of Patent: July 23, 1996Assignee: Seiko Epson CorporationInventors: Koji Akioka, Osamu Kobayashi, Tatsuya Shimoda, Toshiyuki Ishibashi, Ryuichi Ozaki
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Patent number: 5534080Abstract: A method of producing a Mn-Al thin film with excellent magnetic properties for magnetic recording medium use. The method includes magnetron sputtering to form a selective composition of Mn-Al .epsilon.-phase thin film on a low temperature substrate, then applying a heat treatment under the controlled conditions for a desirable temperature and time period, thereby to transform the .epsilon.-phase film to a .tau.-phase film with high value of saturation magnetization and coercivity.Type: GrantFiled: June 1, 1995Date of Patent: July 9, 1996Assignee: National Science Council of Republic of ChinaInventors: Po C. Kuo, Jin H. Huang, Shang C. Chen
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Patent number: 5527399Abstract: Methods for preparing magnetic strips are provided in which the strips are manufactured to a thickness of less than about 0.005 inches and are made of a ferrous alloy having a carbon content of from about 0.4 to about 1.2 weight percent. The strips can be prepared by first manufacturing an alloy having a carbon content below about 0.5 weight percent to the desired thickness and then subjecting the strip to a carburizing step to raise the carbon content in the strip. The strips can also be prepared by controlling the chemistry of the initial alloy and controlling the processing of that alloy until the desired thickness and requisite magnetic properties are obtained. The strips are particularly useful in EAS systems.Type: GrantFiled: February 27, 1995Date of Patent: June 18, 1996Assignee: The Arnold Engineering CompanyInventors: Neil R. Manning, Richard L. Anderson
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Patent number: 5525164Abstract: A Ni--Fe magnetic alloy consists essentially of:77 to 80 wt. % Ni, 3.5 to 5 wt. % Mo, 1.5 to 3 wt. % Cu, 0.1 to 1.1 wt. % Mn, 0.1 wt. % or less Cr, 0.003 wt. % or less S, 0.01 wt. % or less P, 0.005 wt. % or less O, 0.003 wt. % or less N, 0.02 wt. % or less C, 0.001 to 0.05 wt. % Al, 1 wt. % or less Si, 2.6-6 of the weight ratio of Ca to S, (Ca/S), and the balance being Fe and inevitable impurities, satisfies an equation of 3.2.ltoreq.(2.02.times.[Ni]-11.13.times.[Mo]-1.25.times.[Cu]-5.03.times.[M n])/(2.13.times.[Fe]).ltoreq.3.8; and has a Mo segregation ratio defined by a seregration equation satisfying 5% or less, the seregration equation being .vertline.(Mo content in a segregation region-Mo average content)/(Mo average content).vertline..times.100%.A method for producing a magnetic Ni--Fe alloy comprises the steps of: a first heating step of heating an alloy ingot to 1200.degree. to 1300.degree. C. for 10 to 30 hrs; slabbing the heated ingot at a finishing temperature of 950.degree. C.Type: GrantFiled: March 8, 1995Date of Patent: June 11, 1996Assignee: NKK CorporationInventors: Tadashi Inoue, Kiyoshi Tsuru, Shinichi Okimoto, Naokazu Yamamura, Tetsuo Yamamoto, Hirohisa Haiji